JP6209953B2 - Polypropylene resin composition for forming inflation film and method for producing film - Google Patents

Description

  The present invention relates to a polypropylene resin composition for forming an inflation film and a method for producing the film. More specifically, the present invention relates to a method for producing an inflation film that improves the molding stability during inflation molding and enables film molding with excellent transparency. The present invention relates to a polypropylene resin composition and a method for producing an inflation film.

Conventionally, polypropylene resins are widely used particularly in the food packaging field because they are excellent in tensile strength, rigidity, transparency and the like, and are excellent in food hygiene such as non-toxicity and odorlessness. Usually, when a polypropylene resin is used in the packaging field, it is often used in the form of a film.
The film production method includes a T-die molding method, a water-cooled inflation method, an air-cooled inflation method, a tenter-type biaxial stretching method, a tubular-type biaxial stretching method, etc. It is appropriately selected. Among these, the inflation method represented by water-cooled inflation and air-cooled inflation is capable of producing films with simple equipment, and is also suitable for the production of many types of small lots, and is formed at a relatively low temperature. Since it can, it has the characteristic which is excellent also in low odor property. In particular, the air-cooled inflation method has features that the workability is good because the equipment is simple and the width of the film can be easily changed only by adjusting the blow ratio.

However, in inflation molding, in the process of forming a cylindrical molten resin film using an annular die and cooling to form a film, an unstable state such as shaking of the cylindrical resin film (so-called bubbles) is likely to occur. .
In order to solve this problem, for example, in Patent Document 1, 10% by weight of free-end branched polypropylene having a branching index (g ′) of 0.33 prepared by high-energy ionizing radiation is blended with linear polypropylene. A method is disclosed. For example, Patent Document 2 discloses a method for producing a film by air-cooled inflation molding in which a high melt tension polypropylene resin satisfying a specific melt tension (MT) and MFR relationship is blended with a polyolefin resin. For example, Patent Document 3 discloses a method for producing a film by air-cooled inflation molding in which a high melt tension polypropylene resin satisfying a specific melt tension (MT) and MFR relationship is blended with a polypropylene resin.
However, although these methods disclose that the transparency is improved as compared with the case where a high melt tension polypropylene resin is not blended, in some cases, the transparency may be deteriorated.

In the inflation molding, for example, in Patent Document 4, (A) a polymerization is performed using a metallocene catalyst, the MFR is 1 to 20 g / min, and the melting peak temperature (Tm) is 110 ° C. to 135 ° C. , 95-99.9% by weight of a propylene / α-olefin random copolymer having a ratio (Mw / Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of 1.5 to 3.5, and (B) An air-cooled inflation molded polypropylene film comprising a polypropylene resin composition containing 0.1 to 5% by weight of a nucleating agent and having a haze of 5% or less is disclosed.
Moreover, in patent document 5, it superposes | polymerizes using a metallocene catalyst, MFR is 1-20 g / min, melting peak temperature (Tm) is 110 to 135 degreeC, a weight average molecular weight (Mw) and a number average molecular weight (Mn). An air-cooled inflation molded polypropylene film comprising an isotactic propylene / α-olefin random copolymer having a ratio (Mw / Mn) of 1.5 to 3.5 and having a haze of 10% or less It is disclosed.

However, in these methods, although the transparency is good, in some cases, an unstable state such as a bubble shaking during inflation molding may occur.
Therefore, there has been a strong demand for a method for improving stability during inflation molding while maintaining high transparency.

Japanese Patent Laid-Open No. 62-121704 JP 2000-119451 A JP 2003-64193 A JP 2004-182967 A JP 2004-315625 A

  In view of the above problems, an object of the present invention is to use a polypropylene-based resin composition that can hardly produce an unstable state during molding and can easily produce a polypropylene film having high transparency by an inflation method. The object is to provide a method for producing an inflation film.

As a result of intensive studies to solve the above problems, the inventor of the present invention is surprising by combining a specific polypropylene resin (X) having a specific long chain branched structure and a specific propylene resin (Y). Furthermore, the inventors have found that the molding stability at the time of inflation molding is excellent while maintaining high transparency, and have completed the present invention.
The present invention provides the following polypropylene resin composition for forming an inflation film and a method for producing the film.

[1] 1 to 30% by weight of a polypropylene resin (X) having a branched structure that satisfies the following characteristics (i) to (iii), and does not correspond to the polypropylene resin (X), and (a) A polypropylene resin composition for forming an inflation film, comprising 70 to 99% by weight of a propylene resin (Y) satisfying the above characteristics.
(I) MFR is 0.1-30 g / 10min.
(Ii) The branching index g ′ when the absolute molecular weight Mabs is 1 million is 0.55 or more and less than 1.00.
(Iii) Melt tension (MT) (unit: g) is
log (MT) ≧ −0.9 × log (MFR) +0.7 or MT ≧ 15
Satisfy one of the following.
(A) MFR is 0.1-20 g / 10min.

[2] The polypropylene resin composition for forming an inflation film according to the above [1], wherein the propylene resin (Y) is a propylene / α-olefin copolymer having a melting point of 110 to 155 ° C.
[3] The polypropylene resin composition for forming an inflation film according to the above [1] or [2], wherein the propylene resin (Y) is a propylene / ethylene copolymer polymerized using a metallocene catalyst. object.
[4] A method for producing a film, comprising using the polypropylene resin composition for forming an inflation film according to any one of [1] to [3] above, and molding a film by an inflation method.
[5] The method for producing a film according to [4], wherein the inflation method is an air-cooled inflation method.

  The polypropylene resin composition for forming an inflation film of the present invention is excellent in molding stability in film formation by an inflation method, and the obtained film is excellent in transparency.

  Hereinafter, embodiments of the present invention will be described in detail.

The polypropylene resin composition for forming an inflation film of the present invention comprises 1 to 30% by weight of a polypropylene resin (X) having a branched structure that satisfies the following characteristics (i) to (vi), and the polypropylene resin ( It is characterized by comprising 70 to 99% by weight of a propylene resin (Y) that does not fall under X) and satisfies the following characteristics (a).
(I) MFR is 0.1-30 g / 10min.
(Ii) The branching index g ′ when the absolute molecular weight Mabs is 1 million is 0.55 or more and less than 1.00.
(Iii) Melt tension (MT) (unit: g) is
log (MT) ≧ −0.9 × log (MFR) +0.7 or MT ≧ 15
Satisfy one of the following.
(A) MFR is 0.1-20 g / 10min.

[Polypropylene resin (X)]
The polypropylene resin (X) used in the present invention is a polypropylene resin having a branched structure, and satisfies the characteristics (i) to (iii) above.
Each of the above characteristics and a method for producing the polypropylene resin (X) will be specifically described below.

Characteristic (i): MFR
The melt flow rate (MFR) of the polypropylene resin (X) used in the present invention needs to be in the range of 0.1 to 30 g / 10 minutes, preferably 0.3 to 20.0 g / 10 minutes, More preferably, it is 0.5-10.0 g / 10min. Below this range, fluidity is insufficient, causing problems such as excessive load on the extruder when forming a film by the inflation method.On the other hand, if it exceeds, the properties as a high melt tension material are poor due to insufficient tension. Become unsuitable.
The method for controlling the MFR value is well known and can be easily adjusted by adjusting the temperature and pressure, which are the polymerization conditions for the polypropylene resin (X), or by controlling the amount of hydrogen added to the chain transfer agent such as hydrogen during polymerization. Adjustments can be made.

  In the present invention, the MFR of the propylene-based resin is JIS K7210: 1999 “Method of plastic-thermoplastic melt mass flow rate (MFR) and test method for melt volume flow rate (MVR)”, condition M (230 ° C, 2.16 kg load), and the unit is g / 10 minutes.

Characteristic (ii): Branch index g ′
As a direct index that the polypropylene resin (X) used in the present invention has long chain branching, a branching index g ^′ can be mentioned. g ′ is given by the ratio of the intrinsic viscosity [η] lin of the linear polymer having the same molecular weight as the intrinsic viscosity [η] br of the polymer having a long chain branched structure, that is, [η] br / [η] lin. When a long chain branched structure is present, the value is smaller than 1.
The definition is described in, for example, “Developments in Polymer Characterization-4” (JV Dawkins ed. Applied Science Publishers, 1983), and is an index known to those skilled in the art.

The branching index g ′ can be obtained as a function of the absolute molecular weight Mabs by using, for example, a GPC equipped with a light scatterometer and a viscometer as described below.
The polypropylene resin (X) used in the present invention has a g ′ of 0.55 or more and less than 1.00, preferably 0.55 or more and 0.98 when the absolute molecular weight Mabs determined by light scattering is 1,000,000. Hereinafter, it is more preferably 0.75 or more and 0.96 or less, and further preferably 0.78 or more and 0.95 or less.
The polypropylene resin (X) used in the present invention is preferably considered to have a comb-shaped chain as a molecular structure. When the branching index g ′ is less than 0.55, the main chain is few and the side chain is small. In such a case, the melt tension may not be improved, a gel may be formed, or the transparency may be deteriorated. On the other hand, when the branching index g ′ is 1.00, this means that there is no long chain branching, the melt tension tends to be insufficient, and the molding stability during film molding by inflation molding is not improved. .

The lower limit of g ′ is preferably the above value for the following reason.
According to the document “Encyclopedia of Polymer Science and Engineering vol. 2” (John Wiley & Sons 1985 p. 485), the g ′ value of the comb polymer is represented by the following formula.

Here, g is a branching index defined by the rotation radius ratio of the polymer, and ε is a constant determined by the shape of the branched chain and the solvent. According to Table 3 of 487, a value of about 0.7 to 1.0 is reported for the comb chain in a good solvent. λ is the ratio of the main chain in the comb chain, and p is the average number of branches. According to this equation, the number of branches is extremely large for a comb chain, that is, p is infinite, and g ′ = g ^ε = λ ^ε , which is not less than the value of λ ^ε. In general, there will be a lower limit.

On the other hand, the formula of a conventionally known random branched chain that is considered to occur in the case of electron beam irradiation or peroxide modification is given by the formula (19) on page 485 in the same document. In the chain, as the number of branch points increases, the g ′ and g values monotonously decrease, especially without the lower limit. That is, in the present invention, the fact that the g ′ value has a lower limit means that the polypropylene resin (X) having a long-chain branched structure used in the present invention has a structure close to a comb chain. This makes the distinction from random branched chains generated by conventional electron beam irradiation or peroxide modification more clear.
Further, in a branched polymer having a structure close to a comb chain in which g ′ is in the above range, the degree of decrease in melt tension when kneading is repeated is small, and in the process of industrially producing a film, for example, When the end material generated by cutting the portion is subjected to molding again as a recycled material, the decrease in physical properties and moldability is reduced.

A specific method for calculating the branching index g ′ is as follows.
Waters Alliance GPCV2000 is used as a GPC apparatus equipped with a differential refractometer (RI) and a viscosity detector (Viscometer). As the light scattering detector, a DAWN-E manufactured by Wyatt Technology, a multi-angle laser light scattering detector (MALLS) is used. The detectors are connected in the order of MALLS, RI, and Viscometer. The mobile phase solvent is 1,2,4-trichlorobenzene (an antioxidant “Irganox 1076” manufactured by BASF Japan Ltd. is added at a concentration of 0.5 mg / mL).
The flow rate is 1 mL / min, and two columns of Tosoh Corporation GMHHR-H (S) HT are connected and used. The temperature of the column, sample injection section, and each detector is 140 ° C. The sample concentration is 1 mg / mL and the injection volume (sample loop volume) is 0.2175 mL.

In order to obtain the absolute molecular weight (Mabs) obtained from MALLS, the mean square inertia radius (Rg), and the intrinsic viscosity ([η]) obtained from Viscometer, data processing software ASTRA (version 4.73.04) attached to MALLS is used. The calculation is performed with reference to the following documents.
1. "Developments in Polymer Characterization-4" (JV Dawkins ed. Applied Science Publishers, 1983. Chapter 1.)
2. Polymer, 45, 6495-6505 (2004).
3. Macromolecules, 33, 2424-2436 (2000).
4). Macromolecules, 33, 6945-6925 (2000).

The branching index g ′ is a ratio of the intrinsic viscosity ([η] br) obtained by measuring a sample with the above Viscometer and the intrinsic viscosity ([η] lin) obtained separately by measuring a linear polymer ([[ η] br / [η] lin).
When a long-chain branched structure is introduced into a polymer molecule, the radius of inertia becomes smaller than that of a linear polymer molecule having the same molecular weight. Since the intrinsic viscosity becomes smaller as the radius of inertia becomes smaller, the intrinsic viscosity ([η] br) of the branched polymer with respect to the intrinsic viscosity ([η] lin) of the linear polymer having the same molecular weight as the long chain branched structure is introduced. ) Ratio ([η] br / [η] lin) becomes smaller.
Therefore, when the branch index (g ′ = [η] br / [η] lin) is a value smaller than 1, it means that a branch is introduced.
Here, as a linear polymer for obtaining [η] lin, a commercially available homopolypropylene (Novatech PP (registered trademark), grade name: FY6 manufactured by Nippon Polypro Co., Ltd.) is used. Since it is known as the Mark-Houwink-Sakurada equation that the logarithm of [η] lin of a linear polymer has a linear relationship with the logarithm of molecular weight, [η] lin is on the low molecular weight side or the high molecular weight side, A numerical value can be obtained by extrapolating as appropriate.

  In order to make the branching index g ′ 0.55 or more and less than 1.00, it is achieved by introducing a large number of long chain branches, selection of preferred metallocene catalysts described later, combinations thereof, and their ratios, and prepolymerization. It becomes possible by controlling the conditions and polymerizing.

Characteristic (iii): Melt tension (MT)
Furthermore, the polypropylene resin (X) used in the present invention has the following relational expression between melt tension (MT) and MFR:
log (MT) ≧ −0.9 × log (MFR) +0.7
Or MT ≧ 15
You need to meet one of the following:

  Here, MT is Capillograph 1B manufactured by Toyo Seiki Seisakusho Co., Ltd. Capillary: 2.0 mm in diameter, 40 mm in length, cylinder diameter: 9.55 mm, cylinder extrusion speed: 20 mm / min, take-off speed: 4. The melt tension when measured under the conditions of 0 m / min and temperature: 230 ° C. is expressed in grams. However, when the MT of the polypropylene resin (X) is extremely high, the resin may break at a take-up speed of 4.0 m / min. In such a case, the take-up speed is lowered and the take-off speed is reduced. Let MT be the tension at the highest possible speed. The measurement conditions and units of MFR are as described above.

This rule is an index for the polypropylene-based resin (X) having a branched structure to have a sufficient melt tension to improve molding stability when a film is formed by an inflation method. Since it has a correlation with MFR, it is described by a relational expression with MFR.
Thus, the method of defining the melt tension MT by the relational expression with MFR is a normal method for those skilled in the art. The following relational expression has been proposed.
log (MS)> − 0.61 × log (MFR) +0.82
(Here, MS is synonymous with MT.)
Japanese Unexamined Patent Application Publication No. 2003-64193 proposes the following relational expression as a definition of polypropylene having a high melt tension.
11.32 × MFR ^−0.7854 ≦ MT
Furthermore, Japanese Patent Laid-Open No. 2003-94504 proposes the following relational expression as a definition of polypropylene having a high melt tension.
MT ≧ 7.52 × MFR ^−0.576

In the present invention, the polypropylene resin (X) having a branched structure is represented by the relational formula:
log (MT) ≧ −0.9 × log (MFR) +0.7 or MT ≧ 15
If either of these is satisfied, it can be said that the resin has a sufficiently high melt tension, and is useful for film formation by the inflation method.
The polypropylene resin (X) has the following relational expression:
log (MT) ≧ −0.9 × log (MFR) +0.9 or MT ≧ 15
It is more preferable to satisfy | fill, and it is still more preferable to satisfy | fill the following relational expressions.
log (MT) ≧ −0.9 × log (MFR) +1.1 or MT ≧ 15

  Although it is not necessary to provide the upper limit value of MT in particular, when MT exceeds 40 g, the take-up speed is remarkably slowed by the measurement method described above, and measurement becomes difficult. In such a case, since it is considered that the spreadability of the resin is also deteriorated, it is preferably 40 g or less, more preferably 35 g or less, and most preferably 30 g or less.

  In order to satisfy the relational expression of MT and MFR described above, the long chain branching amount of the polypropylene resin (X) may be increased to increase the melt tension. Selection of a preferable metallocene catalyst described later and a combination thereof, It is possible by introducing a lot of long chain branches by controlling the amount ratio and prepolymerization conditions.

[Other characteristics of polypropylene resin (X) having a branched structure]
Characteristic (iv): 25 ° C. Paraxylene soluble component amount (CXS)
The polypropylene resin (X) used in the present invention has high stereoregularity, and it is preferable that there are few low crystalline components that cause stickiness and bleed-out when it becomes a film product. This low crystalline component is evaluated by the amount of xylene soluble component (CXS) at 25 ° C., and it is preferably less than 5.0% by weight, more preferably 3%, based on the total amount of the polypropylene resin (X). 0.0% by weight or less, more preferably 1.0% by weight or less, and particularly preferably 0.5% by weight or less. The lower limit is not particularly limited, but is usually 0.01% by weight or more, preferably 0.03% by weight or more.

The details of the method for measuring CXS are as follows.
A 2 g sample is dissolved in 300 ml of p-xylene (containing 0.5 mg / ml BHT) at 130 ° C. to make a solution, and then left at 25 ° C. for 12 hours. Thereafter, the precipitated polymer is filtered off, p-xylene is evaporated from the filtrate, and further dried under reduced pressure at 100 ° C. for 12 hours to recover room temperature xylene soluble components. The ratio (% by weight) of the weight of the recovered component to the charged sample weight is defined as CXS.

  In order to make CXS less than 5% by weight, it can be produced by using a metallocene catalyst, as will be described later. It is necessary that the reaction conditions are not extremely high and that the amount ratio of the organoaluminum compound to the metallocene complex is not increased too much.

Characteristic (v): mm fraction of three chain of propylene units by ¹³ C-NMR The polypropylene resin (X) used in the present invention is characterized by high stereoregularity. Stereoregularity of the ^height 13 that can be evaluated by ^{C-NMR, 13 C-NMR} mm fraction of the propylene unit triad sequences obtained by it is preferably 95% or more.
As for the mm fraction, the upper limit of the ratio of three propylene unit chains in which the direction of methyl branching in each propylene unit is the same in any three propylene unit chains composed of head-to-tail bonds in the polymer chain is 100%. This mm fraction is a value indicating that the steric structure of the methyl group in the polypropylene molecular chain is controlled isotactically, and the higher the value, the higher the degree of control. If the mm fraction is smaller than this value (95%), the mechanical properties tend to decrease.
Accordingly, the mm fraction of the polypropylene resin (X) is preferably 95% or more, more preferably 96% or more, and still more preferably 97% or more.

In addition, the detail of the measuring method of mm fraction of the propylene unit 3 chain | strand by ¹³ C-NMR is as follows.
A sample of 375 mg is completely dissolved in 2.5 ml of deuterated 1,1,2,2-tetrachloroethane in an NMR sample tube (10φ), and then measured at 125 ° C. by a proton complete decoupling method. The chemical shift sets the central peak of the three peaks of deuterated 1,1,2,2-tetrachloroethane to 74.2 ppm. The chemical shift of other carbon peaks is based on this.
Flip angle: 90 degrees Pulse interval: 10 seconds Resonance frequency: 100 MHz or more Integration frequency: 10,000 times or more Observation range: -20 ppm to 179 ppm
Number of data points: 32768

The analysis of the mm fraction is performed using the measured ¹³ C-NMR spectrum.
The spectrum is assigned with reference to Macromolecules, (1975) 8, 687 and Polymer, 30, 1350 (1989).
Note that a more specific method for determining the mm fraction is described in detail in paragraphs [0053] to [0065] of Japanese Patent Laid-Open No. 2009-275207, and the present invention is performed according to this method. .

  The mm fraction can be 95% or more by using a polymerization catalyst that achieves a highly crystalline polymer, and by using a preferred metallocene catalyst described later for polymerization.

Characteristic (vi): Molecular weight distribution by GPC In addition, it is preferable that the polypropylene resin (X) has a relatively wide molecular weight distribution, and the molecular weight distribution (Mw / Mn) obtained by gel permeation chromatography (GPC) (here, , Mw is preferably a weight average molecular weight and Mn is a number average molecular weight) of 3.0 to 10.0. The molecular weight distribution (Mw / Mn) of the polypropylene resin (X) is more preferably 3.5 to 8.0, and still more preferably 4.0 to 6.0.
Furthermore, it is preferable that Mz / Mw (where Mz is the Z average molecular weight) is 2.5 or more and 10.0 or less as a parameter that more significantly represents the width of the molecular weight distribution. A more preferable range of Mz / Mw is 2.8 to 8.0, and more preferably 3.0 to 6.0.
As the molecular weight distribution is wider, the molding processability is improved, but those having Mw / Mn and Mz / Mw in such ranges are particularly excellent in molding stability during film molding by the inflation method.

The definitions of Mn, Mw and Mz are described in “Basics of Polymer Chemistry” (edited by Polymer Society, Tokyo Kagaku Dojin, 1978) and can be calculated from molecular weight distribution curves by GPC.
And the specific measuring method of GPC is as follows.
Apparatus: Waters GPC (ALC / GPC 150C)
Detector: MIRAN 1A IR detector (measurement wavelength: 3.42 μm) manufactured by FOXBORO Column: AD806M / S (three) manufactured by Showa Denko KK
Mobile phase solvent: orthodichlorobenzene (ODCB)
Measurement temperature: 140 ° C
Flow rate: 1.0 ml / min
Injection volume: 0.2ml
Sample preparation: Prepare a 1 mg / mL solution using ODCB (containing 0.5 mg / mL BHT) and dissolve at 140 ° C. for about 1 hour.

Conversion from the retention capacity obtained by GPC measurement to the molecular weight is performed using a calibration curve prepared in advance by standard polystyrene (PS). The standard polystyrenes used are all the following brands manufactured by Tosoh Corporation.
F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000
A calibration curve is created by injecting 0.2 mL of a solution dissolved in ODCB (containing 0.5 mg / mL BHT) so that each is 0.5 mg / mL. The calibration curve uses a cubic equation obtained by approximation by the least square method.
In addition, the following numerical value is used for the viscosity formula [η] = K × M ^α used for conversion to molecular weight.
PS: K = 1.38 × 10 ⁻⁴ , α = 0.7
PP: K = 1.03 × 10 ⁻⁴ , α = 0.78

  In order to set Mw / Mn to 3.0 or more and 10.0 or less and Mz / Mw to 2.5 or more and 10.0 or less, the temperature and pressure conditions of propylene polymerization are changed, or as the most general technique Can be easily adjusted by a method in which a chain transfer agent such as hydrogen is added during propylene polymerization. Furthermore, when using 2 or more types of the metallocene catalyst mentioned later and a catalyst, it can control by changing the quantity ratio.

Characteristics (vii): As a further additional feature of the polypropylene-based resin having a branched structure according to the degree of strain hardening present invention (X), the strain hardening degree in measurement of extensional viscosity at a strain rate of 0.1s ^-1 (.lambda.max ( 0.1)) is 6.0 or more.
The strain hardening degree (λmax (0.1)) is an index representing the strength at the time of melting, and when this value is large, there is an effect of improving the melt tension. As a result, when the film is formed by the inflation method, the forming stability is easily improved. The strain hardening degree of the polypropylene resin (X) is preferably 6.0 or more, and more preferably 8.0 or more. The upper limit is not particularly defined, but if the value is extremely large, orientation crystallization by strain hardening may be promoted at the time of film forming, for example, there is a concern that the film becomes brittle or transparency and glossiness deteriorate. .

Details of the calculation method of λmax (0.1) are as follows.
The elongational viscosity at a temperature of 180 ° C. and a strain rate = 0.1 s ⁻¹ is plotted on a logarithmic graph with the horizontal axis representing time t (seconds) and the vertical axis representing elongational viscosity ηE (Pa · seconds). On the log-log graph, the viscosity immediately before strain hardening is approximated by a straight line.
Specifically, first, the slope at each time when the extensional viscosity is plotted against time is obtained. In this case, considering that the measurement data of the extensional viscosity is discrete, various averaging methods are used. Is used. For example, there is a method of obtaining the slope of adjacent data and taking a moving average of several surrounding points.
The elongational viscosity is a simple increasing function in the low strain region, gradually approaches a constant value, and if there is no strain hardening, it matches the Trought viscosity after a sufficient time. In particular, the extensional viscosity starts to increase with time from a strain amount (= strain rate × time) of about 1. That is, the slope tends to decrease with time in the low strain region, but tends to increase from about 1 strain, and there is an inflection point on the curve when the extensional viscosity is plotted against time. . Therefore, a point where the slope of each time obtained above takes the minimum value in the range of the distortion amount of about 0.1 to 2.5 is obtained, and a tangent line is drawn at the point, and the straight line has a distortion amount of 4.0. Extrapolate until The maximum value (ηmax) of the extensional viscosity ηE until the strain amount becomes 4.0 is obtained, and the viscosity on the approximate straight line up to that time is ηlin. ηmax / ηlin is defined as λmax (0.1).

Characteristic (viii): Melting point The melting point of the polypropylene resin (X) used in the present invention is preferably 110 to 170 ° C, more preferably 115 ° C or more, and further preferably 120 ° C or more, and more preferably It is 165 ° C. or lower, and further 160 ° C. or lower. When the melting point is lower than 110 ° C., the cooling and solidification becomes too slow during inflation molding, which adversely affects the molding stability, and those having a melting point exceeding 170 ° C. are substantially difficult to produce.
The melting point was determined by using differential operation calorimetry (DSC), once the temperature was raised to 200 ° C. and the thermal history was erased, then the temperature was lowered to 40 ° C. at a temperature lowering rate of 10 ° C./min, and the temperature rising rate was again It is set as the temperature of the endothermic peak top when measured at 10 ° C./min.

[Method for producing polypropylene-based resin (X) having a branched structure]
The polypropylene-based resin (X) having a branched structure is not particularly limited as long as the above-described properties (i) to (iii) are satisfied, but as described above, a low low crystalline component amount, A preferable production method for satisfying all conditions of high stereoregularity, relatively wide molecular weight distribution, range of branching index g ^′ , and high melt tension is a method using a macromer copolymerization method using a combination of metallocene catalysts. is there. As an example of such a method, for example, a method disclosed in Japanese Patent Application Laid-Open No. 2009-57542 can be given.
This method produces a polypropylene having a long-chain branched structure using a catalyst in which a catalyst component having a specific structure having macromer-producing ability and a catalyst component having a specific structure having high molecular weight and macromer copolymerization ability are combined. According to this, industrially effective methods such as bulk polymerization and gas phase polymerization, particularly single-stage polymerization under practical pressure-temperature conditions, and using hydrogen as a molecular weight regulator. It is possible to produce a polypropylene resin having a long-chain branched structure having the desired physical properties.

In the past, it was necessary to increase the branching efficiency by lowering the crystallinity by using a polypropylene component having a low stereoregularity. However, in the above method, a polypropylene component having a sufficiently high stereoregularity is required. The above (iv) and (v) relating to the high stereoregularity and the low amount of low crystalline component, which can be introduced into the side chain by a simple method and are preferable as the polypropylene resin (X) used in the present invention. ) Is preferable.
Further, by using the above-mentioned method, the molecular weight distribution can be broadened by using two kinds of catalysts having greatly different polymerization characteristics, and the above (ii) necessary for the polypropylene resin (X) having a branched structure used in the present invention. It is possible and preferable to satisfy the characteristics of (iii) and (iii), and also the desirable characteristics of (vi) and (vii).

Therefore, a preferable method for producing a polypropylene resin (X) having a branched structure used in the present invention will be described in detail below.
As a preferred method for producing the polypropylene resin (X) having a branched structure, a method for producing a propylene polymer using the following catalyst components (A), (B) and (C) as a propylene polymerization catalyst can be mentioned.
(A): at least one from component [A-1], which is a compound represented by the following general formula (a1),
A transition metal compound belonging to Group 4 of the periodic table of at least one kind from Component [A-2], which is a compound represented by General Formula (a2) described later.
(B): Ion exchange layered silicate (C): Organoaluminum compound

Hereinafter, the catalyst components (A), (B), and (C) will be described in detail.
(1) Catalyst component (A)
(I) Component [A-1]: Compound represented by the following general formula (a1)

[In General Formula (a1), R ¹¹ and R ¹² each independently represent a heterocyclic group containing nitrogen, oxygen or sulfur having 4 to 16 carbon atoms. R ¹³ and R ¹⁴ each independently contain halogen, silicon, oxygen, sulfur, nitrogen, boron, phosphorus, or a plurality of heteroelements selected from these, having 6 to 16 carbon atoms An aryl group, a heterocyclic group containing 6 to 16 carbon atoms, nitrogen, oxygen or sulfur. X ¹¹ and Y ¹¹ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing hydrocarbon group having 1 to 20 carbon atoms, or a halogenated group having 1 to 20 carbon atoms. Represents a hydrocarbon group, an oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, an amino group, or a nitrogen-containing hydrocarbon group having 1 to 20 carbon atoms, Q ¹¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms, It represents a silylene group or a germylene group which may have a hydrocarbon group having 1 to 20 carbon atoms. ]

The heterocyclic group containing nitrogen, oxygen or sulfur having 4 to 16 carbon atoms of R ¹¹ and R ¹² is preferably a 2-furyl group, a substituted 2-furyl group, a substituted 2-thienyl group, It is a substituted 2-furfuryl group, and more preferably a substituted 2-furyl group.
Moreover, as a substituted 2-furyl group, a substituted 2-thienyl group, and a substituted 2-furfuryl group, an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, and a propyl group, Examples include halogen atoms such as fluorine atom and chlorine atom, alkoxy groups having 1 to 6 carbon atoms such as methoxy group and ethoxy group, and trialkylsilyl groups. Of these, a methyl group and a trimethylsilyl group are preferable, and a methyl group is particularly preferable.
Further, R ¹¹ and R ¹² are particularly preferably a 2- (5-methyl) -furyl group. R ¹¹ and R ¹² are preferably the same as each other.

Carbon atoms 6 to 16 of the R ¹³ and R ^14, halogen, silicon, oxygen, sulfur, nitrogen, boron, phosphorus, or may contain a plurality of hetero elements selected from these, the aryl group In the range of 6 to 16 carbon atoms, one or more hydrocarbon group having 1 to 6 carbon atoms, silicon-containing hydrocarbon group having 1 to 6 carbon atoms, 1 to 6 carbon atoms on the aryl cyclic skeleton It may have a halogen-containing hydrocarbon group as a substituent.

At least one of R ¹³ and R ¹⁴ is preferably a phenyl group, a 4-methylphenyl group, a 4-i-propylphenyl group, a 4-t-butylphenyl group, a 4-trimethylsilylphenyl group, or 2,3-dimethyl. A phenyl group, 3,5-di-t-butylphenyl group, 4-phenyl-phenyl group, chlorophenyl group, naphthyl group, or phenanthryl group, more preferably a phenyl group, 4-i-propylphenyl group, 4- t-butylphenyl group, 4-trimethylsilylphenyl group, 4-chlorophenyl group. R ¹³ and R ¹⁴ are preferably the same as each other.

In the general formula (a1), X ¹¹ and Y ¹¹ are auxiliary ligands, and react with the co-catalyst of the catalyst component (B) to generate an active metallocene having olefin polymerization ability. Therefore, as long as this object is achieved, X ¹¹ and Y ¹¹ are not limited in the type of ligand, and are independently a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms. A C1-C20 silicon-containing hydrocarbon group, a C1-C20 halogenated hydrocarbon group, a C1-C20 oxygen-containing hydrocarbon group, an amino group, or a C1-C20 nitrogen-containing hydrocarbon Indicates a group.

In the general formula (a1), Q ¹¹ is a silylene that may have a divalent hydrocarbon group having 1 to 20 carbon atoms and a hydrocarbon group having 1 to 20 carbon atoms that connects two five-membered rings. Represents either a group or a germylene group. When two hydrocarbon groups are present on the silylene group or the germylene group, they may be bonded to each other to form a ring structure.
Specific examples of Q ¹¹ include alkylene groups such as methylene, methylmethylene, dimethylmethylene and 1,2-ethylene; arylalkylene groups such as diphenylmethylene; silylene groups; methylsilylene, dimethylsilylene, diethylsilylene, di ( n-propyl) silylene, di (i-propyl) silylene, alkylsilylene groups such as di (cyclohexyl) silylene, (alkyl) (aryl) silylene groups such as methyl (phenyl) silylene; arylsilylene groups such as diphenylsilylene; tetra An alkyl oligosilylene group such as methyldisilylene; a germylene group; an alkylgermylene group in which the silicon of the above-mentioned divalent hydrocarbon group having 1 to 20 carbon atoms is replaced with germanium; (alkyl) (aryl) germylene Group; arylgermylene group And so on. In these, the silylene group which has a C1-C20 hydrocarbon group, or the germylene group which has a C1-C20 hydrocarbon group is preferable, and an alkylsilylene group and an alkylgermylene group are especially preferable.

Of the compounds represented by the general formula (a1), preferred compounds are specifically exemplified below.
However, in the following, only representative exemplary compounds are described avoiding many complicated examples, and the present invention is not construed as being limited to these compounds.

  Dichloro [1,1′-dimethylsilylenebis {2- (2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (2-thienyl) -4-phenyl -Indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-diphenylsilylenebis {2 -(5-Methyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylgermylenebis {2- (5-methyl-2-furyl) -4-phenyl-indenyl} ] Hafnium, dichloro [1,1′-dimethylgermylenebis {2- (5-methyl-2-thienyl) -4-phenyl-indenyl}] hafniu , Dichloro [1,1′-dimethylsilylenebis {2- (5-t-butyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5 -Trimethylsilyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-phenyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (4,5-dimethyl-2-furyl) -4-phenyl-indenyl}] hafnium dichloride, dichloro [1,1′-dimethylsilylenebis {2- (2- Benzofuryl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-) Ryl) -4- (4-methylphenyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-ipropylphenyl)- Indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-trimethylsilylphenyl) -indenyl}] hafnium, dichloro [1,1′-dimethyl Silylenebis {2- (2-furfuryl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-chlorophenyl) -Indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-fluorophenyl) ) -Indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-trifluoromethylphenyl) -indenyl}] hafnium, dichloro [1, 1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-tert-butylphenyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (2 -Furyl) -4- (1-naphthyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (2-furyl) -4- (2-naphthyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (2-furyl) -4- (2-phenanthryl) -indenyl}] hafnium, dichloro [1,1′-dimethyl Rylenebis {2- (2-furyl) -4- (9-phenanthryl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (1 -Naphthyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (2-naphthyl) -indenyl}] hafnium, dichloro [1,1 '-Dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (2-phenanthryl) -indenyl}] hafnium, dichloro [1,1'-dimethylsilylenebis {2- (5-methyl-2 -Furyl) -4- (9-phenanthryl) -indenyl}] hafnium, dichloro [1,1'-dimethylsilylenebis {2- (5-t-butyl-2-furyl)- -(1-naphthyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-t-butyl-2-furyl) -4- (2-naphthyl) -indenyl}] hafnium, Dichloro [1,1′-dimethylsilylenebis {2- (5-t-butyl-2-furyl) -4- (2-phenanthryl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2 -(5-t-butyl-2-furyl) -4- (9-phenanthryl) -indenyl}] hafnium and the like.

  Of these, more preferred are dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylene. Bis {2- (5-methyl-2-furyl) -4- (4-methylphenyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-ipropylphenyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-trimethylsilylphenyl) -indenyl} ] Hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-chlorophenyl) -indenyl}] hafni Dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (2-naphthyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2 -(5-Methyl-2-furyl) -4- (4-t-butylphenyl) -indenyl}] hafnium.

  Particularly preferred is dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4-phenyl-indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis { 2- (5-Methyl-2-furyl) -4- (4-ipropylphenyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl)- 4- (4-Trimethylsilylphenyl) -indenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-t-butylphenyl) -indenyl} ] Hafnium.

(Ii) Component [A-2]: Compound represented by general formula (a2)

[In General Formula (a2), R ²¹ and R ²² are each independently a hydrocarbon group having 1 to 6 carbon atoms, and R ²³ and R ²⁴ are each independently halogen, silicon, oxygen, It is a C6-C16 aryl group which may contain sulfur, nitrogen, boron, phosphorus, or a plurality of heteroelements selected from these. X ²¹ and Y ²¹ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing hydrocarbon group having 1 to 20 carbon atoms, or a halogenated hydrocarbon having 1 to 20 carbon atoms. Group, an oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, an amino group, or a nitrogen-containing hydrocarbon group having 1 to 20 carbon atoms, Q ²¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms, carbon number It represents a silylene group or a germylene group which may have 1 to 20 hydrocarbon groups. M ²¹ is zirconium or hafnium. ]

R ²¹ and R ²² are each independently a hydrocarbon group having 1 to 6 carbon atoms, preferably an alkyl group, and more preferably an alkyl group having 1 to 4 carbon atoms. Specific examples include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, n-pentyl, i-pentyl, n-hexyl, and preferably methyl. , Ethyl, n-propyl.

In addition, R ²³ and R ²⁴ each independently contain a halogen having 6 to 16 carbon atoms, preferably 6 to 12 carbon atoms, silicon, or a plurality of hetero elements selected from these. It is a good aryl group. Preferable examples include phenyl, 3-chlorophenyl, 4-chlorophenyl, 3-fluorophenyl, 4-fluorophenyl, 4-methylphenyl, 4-i-propylphenyl, 4-t-butylphenyl, 4-trimethylsilylphenyl, 4 -(2-fluoro-4-biphenylyl), 4- (2-chloro-4-biphenylyl), 1-naphthyl, 2-naphthyl, 4-chloro-2-naphthyl, 3-methyl-4-trimethylsilylphenyl, 3, Examples include 5-dimethyl-4-t-butylphenyl, 3,5-dimethyl-4-trimethylsilylphenyl, 3,5-dichloro-4-trimethylsilylphenyl, and the like.

Further, the X ²¹ and Y ²¹ are auxiliary ligands, it reacts with the cocatalyst of the catalyst component (B) to form an active metallocene having olefin polymerizability. Therefore, as long as this object is achieved, X ²¹ and Y ²¹ are not limited in the type of ligand, and are independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, C1-C20 silicon-containing hydrocarbon group, C1-C20 halogenated hydrocarbon group, C1-C20 oxygen-containing hydrocarbon group, amino group, or C1-C20 nitrogen-containing hydrocarbon group Indicates.

Q ²¹ is a binding group that bridges two conjugated five-membered ring ligands, and has a divalent hydrocarbon group having 1 to 20 carbon atoms and a hydrocarbon group having 1 to 20 carbon atoms. A silylene group or a germylene group having a hydrocarbon group having 1 to 20 carbon atoms, preferably a substituted silylene group or a substituted germylene group. The substituent bonded to silicon and germanium is preferably a hydrocarbon group having 1 to 12 carbon atoms, and two substituents may be linked.

Specific examples of Q ²¹ include methylene, dimethylmethylene, ethylene-1,2-diyl, dimethylsilylene, diethylsilylene, diphenylsilylene, methylphenylsilylene, 9-silafluorene-9,9-diyl, dimethylsilylene, Examples include diethylsilylene, diphenylsilylene, methylphenylsilylene, 9-silafluorene-9,9-diyl, dimethylgermylene, diethylgermylene, diphenylgermylene, methylphenylgermylene, and the like.

Further, M ²¹ is zirconium or hafnium, preferably hafnium.

As a non-limiting example of the metallocene compound represented by the general formula (a2), the following can be preferably exemplified.
However, the following describes only typical exemplary compounds while avoiding many complicated examples, and the present invention is not construed as being limited to these compounds, and various ligands and cross-linking groups are described. It is obvious that an auxiliary ligand can be used arbitrarily. In the following, a compound in which the central metal is hafnium is described, but a compound replacing zirconium is also treated as disclosed in this specification.

  Dichloro {1,1′-dimethylsilylenebis (2-methyl-4-phenyl-4-hydroazurenyl)} hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4 -Hydroazulenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-t-butylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis { 2-methyl-4- (4-trimethylsilylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (3-chloro-4-t-butylphenyl)- 4-hydroazulenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- ( -Methyl-4-t-butylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (3-chloro-4-trimethylsilylphenyl) -4-hydroazurenyl} ] Hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (3-methyl-4-trimethylsilylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2 -Methyl-4- (1-naphthyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (2-naphthyl) -4-hydroazurenyl}] hafnium, dichloro [ 1,1′-dimethylsilylenebis {2-methyl-4- (4-chloro-2-naphthyl)- -Hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (2-fluoro-4-biphenylyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-Methyl-4- (2-chloro-4-biphenylyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (9-phenanthryl) -4-hydroazurenyl] }] Hafnium, dichloro [1,1′-dimethylsilylenebis {2-ethyl-4- (4-chlorophenyl) -4-hydroazulenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-n-propyl -4- (3-Chloro-4-trimethylsilylphenyl) -4-hydroazurenyl}] huff Nitrogen, dichloro [1,1′-dimethylsilylenebis {2-ethyl-4- (3-chloro-4-tert-butylphenyl) -4-hydroazulenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis { 2-ethyl-4- (3-methyl-4-trimethylsilylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylgermylenebis {2-methyl-4- (2-fluoro-4-biphenylyl) ) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylgermylenebis {2-methyl-4- (4-t-butylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′- (9-silafluorene-9,9-diyl) bis {2-ethyl-4- (4-chlorophenyl) -4-hydroazurenyl}] Funium, dichloro [1,1′-dimethylsilylenebis {2-ethyl-4- (4-chloro-2-naphthyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-ethyl -4- (2-fluoro-4-biphenylyl) -4-hydroazulenyl}] hafnium, dichloro [1,1 ′-(9-silafluorene-9,9-diyl) bis {2-ethyl-4- (3 5-dichloro-4-trimethylsilylphenyl) -4-hydroazurenyl}] hafnium and the like.

  Of these, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2- Methyl-4- (3-chloro-4-trimethylsilylphenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-ethyl-4- (2-fluoro-4-biphenylyl) -4 -Hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-ethyl-4- (4-chloro-2-naphthyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-Ethyl-4- (3-methyl-4-trimethylsilylphenyl) -4-hydroazurenyl}] ha Dichloro, [1,1 ′-(9-silafluorene-9,9-diyl) bis {2-ethyl-4- (3,5-dichloro-4-trimethylsilylphenyl) -4-hydroazurenyl}] hafnium, is there.

  Particularly preferably, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-ethyl -4- (2-Fluoro-4-biphenylyl) -4-hydroazurenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-ethyl-4- (3-methyl-4-trimethylsilylphenyl) -4- Hydroazurenyl}] hafnium, dichloro [1,1 ′-(9-silafluorene-9,9-diyl) bis {2-ethyl-4- (3,5-dichloro-4-trimethylsilylphenyl) -4-hydroazurenyl}] Hafnium.

(2) Catalyst component (B)
The catalyst component (B) preferably used for producing the polypropylene resin (X) is an ion-exchange layered silicate.
(I) Types of ion-exchanged layered silicates Ion-exchanged layered silicates (hereinafter sometimes simply referred to as silicates) are surfaces formed by ionic bonds or the like that are parallel to each other with a binding force. A silicate compound having a stacked crystal structure and containing exchangeable ions. Most silicates are mainly produced as a main component of clay minerals in nature, and therefore often contain impurities (quartz, cristobalite, etc.) other than ion-exchanged layered silicates. Good. Depending on the type, amount, particle size, crystallinity, and dispersion state of these impurities, it may be preferable to pure silicate, and such a complex is also included in the catalyst component (B).
The silicate to be used is not limited to a natural product, and may be an artificial synthetic product or may contain them.

Specific examples of the silicate include the following layered silicates described in Haruo Shiramizu “Clay Mineralogy” Asakura Shoten (1995).
That is, montmorillonite, sauconite, beidellite, nontronite, saponite, hectorite, stemite and other smectites, vermiculite and other vermiculites, mica, illite, sericite and sea chlorite and other mica, attapulgite, sepiolite and palygorskite , Bentonite, pyrophyllite, talc, chlorite group, etc.
The silicate is preferably a silicate in which the main component silicate has a 2: 1 type structure, more preferably a smectite group, and particularly preferably montmorillonite. The type of interlayer cation is not particularly limited, but a silicate containing an alkali metal or an alkaline earth metal as a main component of the interlayer cation is preferable from the viewpoint of being relatively easy and inexpensive to obtain as an industrial raw material.

(Ii) Chemical treatment of ion-exchangeable layered silicate The ion-exchangeable layered silicate of the catalyst component (B) can be used as it is without any particular treatment, but it is preferable to perform chemical treatment. Here, the chemical treatment of the ion-exchange layered silicate can be any of a surface treatment for removing impurities adhering to the surface and a treatment that affects the structure of the clay. Specifically, , Acid treatment, alkali treatment, salt treatment, organic matter treatment and the like.

<Acid treatment>:
In addition to removing impurities on the surface, the acid treatment can elute some or all of cations such as Al, Fe, Mg, etc. in the crystal structure.
The acid used in the acid treatment is preferably selected from hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid and oxalic acid.
Two or more salts (described in the next section) and acid may be used for the treatment. The treatment conditions with salts and acids are not particularly limited. Usually, the salt and acid concentrations are 0.1 to 50% by weight, the treatment temperature is room temperature to boiling point, and the treatment time is 5 minutes to 24 hours. It is preferable to carry out the process under the condition of selecting and eluting at least a part of the substance constituting at least one compound selected from the group consisting of ion-exchangeable layered silicates. In addition, salts and acids are generally used in an aqueous solution.
In addition, you may use what combined the following acids and salts as a processing agent. Moreover, the combination of these acids and salts may be sufficient.

<Salt treatment>:
Cations that are preferably 40% or more, more preferably 60% or more, of the exchangeable Group 1 metal cations contained in the ion-exchange layered silicate before being treated with salts, dissociated from the salts shown below. It is preferable to perform ion exchange.
The salt used in the salt treatment for the purpose of ion exchange is a group consisting of a cation containing at least one atom selected from the group consisting of group 1 to 14 atoms, a halogen atom, an inorganic acid, and an organic acid. A compound comprising at least one anion selected from the group consisting of at least one anion selected from the group consisting of group 2 to 14 atoms, Cl, Br, I, F, PO ₄ , SO ₄ , NO ₃ , CO ₃ , C ₂ O ₄ , ClO ₄ , OOCCH ₃ , CH ₃ COCHCOCH ₃ , OCl ₂ , O (NO ₃ ) ₂ , O (ClO ₄ ) ₂ , O (SO ₄ ) At least one anion selected from the group consisting of OH, O ₂ Cl ₂ , OCl ₃ , OOCH, OOCCH ₂ CH ₃ , C ₂ H ₄ O ₄ and C ₅ H ₅ O ₇ Is a compound consisting of

Preferred examples of such _{salts, LiF, LiCl, LiBr, LiI} , Li 2 SO 4, Li (CH 3 COO), LiCO 3, Li (C 6 H 5 O 7), LiCHO 2, LiC 2 O ₄ , LiClO ₄ , Li ₃ PO ₄ , CaCl ₂ , CaSO ₄ , CaC ₂ O ₄ , Ca (NO ₃ ) ₂ , Ca ₃ (C ₆ H ₅ O ₇ ) ₂ , MgCl ₂ , MgBr ₂ , MgSO ₄ , Mg (PO ₄ ) ₂ , Mg (ClO ₄ ) ₂ , MgC ₂ O ₄ , Mg (NO ₃ ) ₂ , Mg (OOCCH ₃ ) ₂ , MgC ₄ H ₄ O _{4 and the} like.

Further, Ti (OOCCH ₃ ) ₄ , Ti (CO ₃ ) ₂ , Ti (NO ₃ ) ₄ , Ti (SO ₄ ) ₂ , TiF ₄ , TiCl ₄ , Zr (OOCCH ₃ ) ₄ , Zr (CO ₃ ) ₂ , Zr (NO ₃ ) ₄ , Zr (SO ₄ ) ₂ , ZrF ₄ , ZrCl ₄ , ZrOCl ₂ , ZrO (NO ₃ ) ₂ , ZrO (ClO ₄ ) ₂ , ZrO (SO ₄ ), HF (OOCCH ₃ ) ₄ , HF (CO ₃ ) ₂ , HF (NO ₃ ) ₄ , HF (SO ₄ ) ₂ , HFOCl ₂ , HFF ₄ , HFCl ₄ , V (CH ₃ COCHCOCH ₃ ) ₃ , VOSO ₄ , VOCl ₃ , VCl ₃ , VCl ₄ , VBr _{3 and the} like.

Also, Cr (CH ₃ COCHCOCH ₃ ) ₃ , Cr (OOCCH ₃ ) ₂ OH, Cr (NO ₃ ) ₃ , Cr (ClO ₄ ) ₃ , CrPO ₄ , Cr ₂ (SO ₄ ) ₃ , CrO ₂ Cl ₂ , CrF _{3, CrCl 3, CrBr 3,} CrI 3, Mn (OOCCH 3) 2, Mn (CH 3 COCHCOCH 3) 2, MnCO 3, Mn (NO 3) 2, MnO, Mn (ClO 4) 2, MnF 2, MnCl ₂ , Fe (OOCCH ₃ ) ₂ , Fe (CH ₃ COCHCOCH ₃ ) ₃ , FeCO ₃ , Fe (NO ₃ ) ₃ , Fe (ClO ₄ ) ₃ , FePO ₄ , FeSO ₄ , Fe ₂ (SO ₄ ) ₃ , FeF ₃ FeCl ₃ , FeC ₆ H ₅ O _{7 and the} like.

In addition, Co (OOCCH ₃ ) ₂ , Co (CH ₃ COCHCOCH ₃ ) ₃ , CoCO ₃ , Co (NO ₃ ) ₂ , CoC ₂ O ₄ , Co (ClO ₄ ) ₂ , Co ₃ (PO ₄ ) ₂ , CoSO ₄ , CoF ₂ , CoCl ₂ , NiCO ₃ , Ni (NO ₃ ) ₂ , NiC ₂ O ₄ , Ni (ClO ₄ ) ₂ , NiSO ₄ , NiCl ₂ , NiBr _{2 and the} like.
Furthermore, Zn (OOCCH ₃ ) ₂ , Zn (CH ₃ COCHCOCH ₃ ) ₂ , ZnCO ₃ , Zn (NO ₃ ) ₂ , Zn (ClO ₄ ) ₂ , Zn ₃ (PO ₄ ) ₂ , ZnSO ₄ , ZnF ₂ , ZnCl ₂ , AlF ₃ , AlCl ₃ , AlBr ₃ , AlI ₃ , Al ₂ (SO ₄ ) ₃ , Al ₂ (C ₂ O ₄ ) ₃ , Al (CH ₃ COCHCOCH ₃ ) ₃ , Al (NO ₃ ) ₃ , AlPO ₄ , GeCl ₄ , GeBr ₄ , GeI _{4 and the} like.

<Alkali treatment>:
In addition to acid and salt treatment, the following alkali treatment or organic matter treatment may be performed as necessary. Examples of the treating agent used in the alkali treatment include LiOH, NaOH, KOH, Mg (OH) ₂ , Ca (OH) ₂ , Sr (OH) ₂ , Ba (OH) _{2 and the} like.

<Organic treatment>:
Examples of the organic treatment agent used for the organic treatment include trimethylammonium, triethylammonium, N, N-dimethylanilinium, triphenylphosphonium, and the like.
Examples of the anion constituting the organic treatment agent include hexafluorophosphate, tetrafluoroborate, and tetraphenylborate other than the anion exemplified as the anion constituting the salt treatment agent. However, it is not limited to these.

Moreover, these processing agents may be used independently and may be used in combination of 2 or more types. These combinations may be used in combination for the treatment agent added at the start of the treatment, or may be used in combination for the treatment agent added during the treatment. Further, the chemical treatment can be performed a plurality of times using the same or different treatment agents.
These ion-exchange layered silicates usually contain adsorbed water and interlayer water. In the present invention, it is preferable to remove these adsorbed water and interlayer water and use them as the catalyst component (B).

  The heat treatment method of the ion-exchange layered silicate adsorbed water and interlayer water is not particularly limited, but it is necessary to select conditions so that interlayer water does not remain and structural destruction does not occur. The heating time is 0.5 hour or longer, preferably 1 hour or longer. At that time, the water content of the catalyst component (B) after the removal is 3% by weight or less when the water content when dehydrating for 2 hours under the conditions of a temperature of 200 ° C. and a pressure of 1 mmHg is 0% by weight, It is preferably 1% by weight or less.

  As described above, particularly preferable as the catalyst component (B) is an ion-exchange layered silicate having a water content of 3% by weight or less, which is obtained by performing a salt treatment and / or an acid treatment.

  The ion-exchange layered silicate can be treated with a catalyst component (C) of an organoaluminum compound, which will be described later, before formation of a catalyst or use as a catalyst, which is preferable. Although there is no restriction | limiting in the usage-amount of the catalyst component (C) with respect to 1g of ion-exchange layered silicate, Usually, 20 mmol or less, Preferably it is 0.5 mmol or more and 10 mmol or less. There is no limitation on the processing temperature and time, and the processing temperature is usually from 0 ° C. to 70 ° C., and the processing time is from 10 minutes to 3 hours. It is also possible and preferable to wash after the treatment. As the solvent, the same hydrocarbon solvent as that used in the prepolymerization or slurry polymerization described later is used.

The catalyst component (B) is preferably spherical particles having an average particle size of 5 μm or more. If the particle shape is spherical, a natural product or a commercially available product may be used as it is, or a particle whose particle shape and particle size are controlled by granulation, sizing, fractionation, or the like may be used.
Examples of the granulation method used here include a stirring granulation method and a spray granulation method, but commercially available products can also be used.
Moreover, you may use organic substance, an inorganic solvent, inorganic salt, and various binders in the case of granulation.
The spherical particles obtained as described above desirably have a compressive fracture strength of 0.2 MPa or more, particularly preferably 0.5 MPa or more, in order to suppress crushing and generation of fine powder in the polymerization process. In the case of such particle strength, the effect of improving the particle properties is effectively exhibited especially when prepolymerization is performed.

(3) Catalyst component (C)
The catalyst component (C) is an organoaluminum compound. Organic aluminum compounds used as the catalyst component (C) has the general ^{_{formula: (AlR 31 q Z 3-}} q) a compound represented by _p is suitable.
In the present invention, it goes without saying that the compounds represented by this formula can be used alone, in combination of two or more, or in combination. In this formula, R ³¹ represents a hydrocarbon group having 1 to 20 carbon atoms, and Z represents a halogen, hydrogen, an alkoxy group or an amino group. q represents an integer of 1 to 3, and p represents an integer of 1 to 2, respectively.
R ³¹ is preferably an alkyl group, and Z is a chlorine atom when it is halogen, a C 1-8 alkoxy group when it is an alkoxy group, and a carbon atom number 1 when it is an amino group. An amino group of ˜8 is preferred.

Specific examples of the organoaluminum compound include trimethylaluminum, triethylaluminum, trinormalpropylaluminum, trinormalbutylaluminum, triisobutylaluminum, trinormalhexylaluminum, trinormaloctylaluminum, trinormaldecylaluminum, diethylaluminum chloride, diethylaluminum. Examples thereof include sesquichloride, diethylaluminum hydride, diethylaluminum ethoxide, diethylaluminum dimethylamide, diisobutylaluminum hydride, and diisobutylaluminum chloride.
Of these, trialkylaluminum and alkylaluminum hydride having p = 1 and q = 3 are preferable. More preferably, it is trialkylaluminum in which R ³¹ is an alkyl group having 1 to 8 carbon atoms.

(4) Catalyst formation / preliminary polymerization In the catalyst, the above catalyst components (A) to (C) are contacted in the (preliminary) polymerization tank simultaneously or continuously, or once or multiple times. Can be formed.
The contact of each component is usually carried out in an aliphatic hydrocarbon or aromatic hydrocarbon solvent. Although contact temperature is not specifically limited, It is preferable to carry out between -20 degreeC-150 degreeC. As the contact order, any desired combination can be used, but particularly preferable ones for each component are as follows.
When the catalyst component (C) is used, the catalyst component (A), the catalyst component (B), or the catalyst component (A) and the catalyst are brought into contact before the catalyst component (A) and the catalyst component (B) are brought into contact with each other. Contacting catalyst component (C) with both components (B), or contacting catalyst component (C) with catalyst component (A) and catalyst component (B), or catalyst component Although it is possible to contact the catalyst component (C) after contacting the catalyst component (B) with (A), preferably, before contacting the catalyst component (A) with the catalyst component (B), This is a method of contacting any one with the catalyst component (C).
Moreover, after contacting each component, it is possible to wash with an aliphatic hydrocarbon or an aromatic hydrocarbon solvent.

The amount of catalyst components (A), (B), and (C) used is arbitrary. For example, the amount of the catalyst component (A) used relative to the catalyst component (B) is preferably in the range of 0.1 μmol to 1,000 μmol, particularly preferably 0.5 μmol to 500 μmol, relative to 1 g of the catalyst component (B). The amount of the catalyst component (C) relative to the catalyst component (A) is preferably a transition metal molar ratio of 0.01 to 5 × 10 ⁶ , particularly preferably within a range of 0.1 to 1 × 10 ^4. preferable.

The proportion of the component [A-1] (compound represented by the general formula (a1)) and the component [A-2] (compound represented by the general formula (a2)) is polypropylene resin (X) The molar ratio of the transition metal of [A-1] to the total amount of the components [A-1] and [A-2] is preferably 0.30 or more, 0 .99 or less.
By changing this ratio, it is possible to adjust the balance between melt physical properties and catalyst activity. That is, from the component [A-1], a low molecular weight terminal vinyl macromer is produced, and from the component [A-2], a high molecular weight body obtained by copolymerizing a part of the macromer is produced. Therefore, by changing the ratio of the component [A-1], the average molecular weight, molecular weight distribution, bias of the molecular weight distribution toward the high molecular weight side, very high molecular weight component, branch (amount, length, Distribution) can be controlled, whereby the melt properties such as branching index g ′ and melt tension can be controlled.

In order to produce the polypropylene resin (X), the molar ratio is preferably 0.30 or more, more preferably 0.40 or more, and further preferably 0.5 or more. The upper limit is preferably 0.99 or less, and preferably 0.95 or less, and more preferably 0.90 or less in order to efficiently obtain a polypropylene resin (X) with high catalytic activity. Range.
In addition, by using component [A-1] within the above range, it is possible to adjust the balance between the average molecular weight and the catalytic activity with respect to the amount of hydrogen.

  The catalyst is preferably subjected to a prepolymerization treatment which consists of contacting it with an olefin and polymerizing it in a small amount. By performing the prepolymerization treatment, gel formation can be prevented when the main polymerization is performed. The reason is considered to be that long-chain branches can be uniformly distributed among the polymer particles when the main polymerization is performed, and the melt physical properties can be improved thereby.

The olefin used in the prepolymerization is not particularly limited, but propylene, ethylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-butene, vinylcycloalkane, Styrene and the like can be exemplified. The olefin feed method may be any method such as a feed method for maintaining the olefin at a constant rate or a constant pressure in the reaction tank, a combination thereof, or a stepwise change.
The temperature and time of the prepolymerization are not particularly limited, but are preferably in the range of −20 ° C. to 100 ° C. and 5 minutes to 24 hours, respectively. The amount of prepolymerization is preferably 0.01 to 100, more preferably 0.1 to 50 in terms of a weight ratio with respect to the catalyst component (B). Moreover, a catalyst component (C) can also be added or added at the time of prepolymerization. It is also possible to wash after the prepolymerization.

  In addition, a method of coexisting a polymer such as polyethylene or polypropylene, or a solid of an inorganic oxide such as silica or titania, at the time of contacting or after contacting each of the above components is also possible.

(5) Use of Catalyst / Propylene Polymerization Any polymerization mode can be used as long as the olefin polymerization catalyst including the catalyst component (A), the catalyst component (B), and the catalyst component (C) is in efficient contact with the monomer. Can be adopted.
Specifically, a slurry method using an inert solvent, a so-called bulk method using a propylene as a solvent without using an inert solvent as a solvent, a solution polymerization method, or a monomer without using a liquid solvent substantially. A gas phase method can be used. Moreover, the method of performing continuous polymerization and batch type polymerization is also applied. In addition to single-stage polymerization, it is possible to carry out multistage polymerization of two or more stages.
In the case of slurry polymerization, a saturated aliphatic or aromatic hydrocarbon such as hexane, heptane, pentane, cyclohexane, benzene, toluene, or the like is used alone or as a polymerization solvent.

The polymerization temperature is usually 0 ° C. or higher and 150 ° C. or lower. In particular, when bulk polymerization is used, the temperature is preferably 40 ° C or higher, more preferably 50 ° C or higher. The upper limit is preferably 80 ° C. or lower, and more preferably 75 ° C. or lower.
Furthermore, when using vapor phase polymerization, 40 degreeC or more is preferable, More preferably, it is 50 degreeC or more. The upper limit is preferably 100 ° C. or lower, more preferably 90 ° C. or lower.
The polymerization pressure is preferably 1.0 MPa or more and 5.0 MPa or less. In particular, when bulk polymerization is used, the pressure is preferably 1.5 MPa or more, more preferably 2.0 MPa or more. The upper limit is preferably 4.0 MPa or less, more preferably 3.5 MPa or less.

Furthermore, when using vapor phase polymerization, 1.5 MPa or more is preferable, and 1.7 MPa or more is more preferable. Further, the upper limit is preferably 2.5 MPa or less, and more preferably 2.3 MPa or less.
Furthermore, as a molecular weight regulator and for the activity improvement effect, hydrogen is supplementarily in a molar ratio with respect to propylene, preferably in the range of 1.0 × 10 ⁻⁶ or more and 1.0 × 10 ⁻² or less. Can be used.

Also, by changing the amount of hydrogen used, in addition to the average molecular weight of the polymer to be produced, the molecular weight distribution, the deviation of the molecular weight distribution toward the high molecular weight side, very high molecular weight components, branching (amount, length, Distribution) can be controlled, whereby the melt physical properties characterizing polypropylene having a long chain branching structure such as MFR, branching index, and melt tension can be controlled.
Therefore, hydrogen should be used at a molar ratio to propylene of 1.0 × 10 ⁻⁶ or more, preferably 1.0 × 10 ⁻⁵ or more, more preferably 1.0 × 10 ⁻⁴ or more. Is good. The upper limit is 1.0 × 10 ⁻² or less, preferably 0.9 × 10 ⁻² or less, and more preferably 0.8 × 10 ⁻² or less.

In addition to the propylene monomer, copolymerization using an α-olefin comonomer having 2 to 20 carbon atoms excluding propylene, for example, ethylene and / or 1-butene as a comonomer may be performed depending on the application.
Therefore, in order to obtain a polypropylene resin (X) used in the present invention having a good balance between catalytic activity and melt properties, ethylene and / or 1-butene is used in an amount of 15 mol% or less based on propylene. More preferably, it is 10 mol% or less, More preferably, it is 7 mol% or less.

  When propylene is polymerized using the catalyst and polymerization method exemplified here, one end of the polymer is mainly propenyl from the active species derived from the catalyst component [A-1] by a special chain transfer reaction generally called β-methyl elimination. The structure is shown and so-called macromers are produced. This macromer can generate a higher molecular weight and is taken into the active species derived from the catalyst component [A-2] having a better copolymerization property, and it is considered that the macromer copolymerization proceeds. Therefore, it is considered that a comb chain is mainly used as a branched structure of a polypropylene resin having a long chain branched structure.

[Propylene Resin (Y): Polypropylene, Propylene Random Copolymer]
The propylene resin (Y) blended with the polypropylene resin (X) having the branched structure described above does not correspond to the polypropylene resin (X) and has an MFR of 0.1 to 20 g / 10 min. System resin is used.
When another resin is used instead of the propylene resin (Y), for example, when an ethylene-α-olefin copolymer is used, the compatibility with the polypropylene resin (X) is inferior. Problems such as insufficient transparency arise.

The propylene-based resin (Y) may be a homopolymer of polypropylene, a copolymer of propylene and ethylene and / or an α-olefin having 4 to 20 carbon atoms, or a plurality thereof. Although a so-called block copolymer may be included, a propylene-α-olefin random copolymer is preferable from the viewpoint of transparency, and a propylene-ethylene random copolymer is more preferable.
When propylene-type resin (Y) is a propylene-ethylene random copolymer, ethylene content E (Y) becomes like this. Preferably it is 0.1-6.0 weight%, More preferably, it is 0.5-5. 0% by weight. If the ethylene content exceeds 6.0% by weight, the crystallinity decreases, so the melting point becomes too low, and cooling solidification becomes too slow during inflation molding, which may adversely affect molding stability. When the propylene resin (Y) is a mixture of a plurality of components including a propylene-ethylene random copolymer, if the ethylene content of one of the components is less than 6.0% by weight, the propylene resin Since the melting point of (Y) does not become too low, there is no problem even if the ethylene content of other components exceeds 6.0% by weight.

The melt flow rate (MFR (Y)) of the propylene-based resin (Y) is 0.1 to 20 g / 10 minutes, preferably 0.5 to 20 g / 10 minutes, more preferably 0.5 to 10 g / minute. It is. When MFR is smaller than 0.1 g / 10 min, the molding processability and melt fluidity are inferior. On the other hand, when MFR is larger than 20 g / 10 min, the bubble stability at the time of forming an inflation film is impaired. As a result, film formation itself becomes difficult.
The melt flow rate (MFR (Y)) is measured at 230 ° C. and a load of 2.16 kg according to JIS K7210.

The melting point of the propylene-based resin (Y) is preferably 110 to 155 ° C, more preferably 115 ° C or more, further 120 ° C or more, and more preferably 150 ° C or less, and further 145 ° C or less. is there. When the melting point is lower than 110 ° C., the cooling and solidification becomes too slow at the time of inflation molding, which adversely affects the molding stability. When the melting point exceeds 155 ° C., the transparency tends to deteriorate particularly during the air-cooled inflation molding. Therefore, it is not preferable.
The melting point was determined by using differential operation calorimetry (DSC), once the temperature was raised to 200 ° C. and the thermal history was erased, then the temperature was lowered to 40 ° C. at a temperature lowering rate of 10 ° C./min, and the temperature rising rate was again It is set as the temperature of the endothermic peak top when measured at 10 ° C./min.

  The propylene-based resin (Y) preferably has a ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) in GPC measurement of 2 to 10. When Mw / Mn is larger than 10, the low molecular weight component increases, which is not preferable because it adversely affects the gloss of the film surface or deteriorates the blocking performance.

The relationship between MT and MFR of the propylene-based resin (Y) used in the present invention is not particularly limited, but it does not have to be of a so-called high melt tension, and therefore is different from polypropylene-based resin (X). It is not necessary to have a branched structure, and it is preferable to use a resin that satisfies the following formulas (1) and (2), which are the relational expressions of the following melt tension (MT) and MFR.
log (MT) <− 0.9 × log (MFR) +0.7 Formula (1)
−0.9 × log (MFR) + 0.2 ≦ log (MT) Formula (2)

Here, the measurement conditions and units of MT and MFR are as described above.
When the propylene-based resin (Y) does not satisfy the relationship of the above formula (1), the melt tension of the entire polypropylene-based resin composition for forming an inflation film of the present invention is too high, and when performing film molding by the inflation method, Oriented crystallization may be accelerated, and as a result, for example, the film may become brittle or the transparency may deteriorate.
In addition, when the propylene resin (Y) does not satisfy the above formula (2), the melt tension of the entire polypropylene resin composition for forming an inflation film of the present invention becomes too low, and the molding stability may deteriorate. is there.

  Although what was obtained by the well-known method can be used for propylene-type resin (Y), what was obtained by especially the superposition | polymerization using a metallocene catalyst is preferable. The metallocene catalyst uses a narrower molecular weight distribution, the crystallinity distribution is narrower, and the amount of low crystalline components produced is less than the Ziegler-Natta catalyst. In addition to being excellent, the film obtained is particularly excellent in transparency when air-cooled inflation molding is performed.

  The metallocene catalyst includes (i) a transition metal compound belonging to Group 4 of the periodic table (so-called metallocene compound) containing a ligand having a cyclopentadienyl skeleton, and (ii) a stable ionic state by reacting with the metallocene compound. It is a catalyst comprising an activatable cocatalyst and, if necessary, (iii) an organoaluminum compound, and any known catalyst can be used. The metallocene compound is preferably a bridged metallocene compound capable of stereoregular polymerization of propylene, and more preferably a bridged metallocene compound capable of isoregular polymerization of propylene.

  Examples of (i) metallocene compounds include JP-A-60-35007, JP-A-63-130314, JP-A-63-295607, JP-A-1-275609, JP-A-2-41303, and JP-A-2-41303. JP-A-2-131488, JP-A-2-76887, JP-A-3-163888, JP-A-4-30087, JP-A-4-21694, JP-A-5-43616, JP-A-5-209913, JP-A-6 No. 239914, JP-A-7-504934, JP-A-8-85708, etc. can be preferably used.

  More specifically, methylene bis (2-methylindenyl) zirconium dichloride, ethylenebis (2-methylindenyl) zirconium dichloride, ethylene 1,2- (4-phenylindenyl) (2-methyl-4-phenyl) -4H-azulenyl) zirconium dichloride, isopropylidene (cyclopentadienyl) (fluorenyl) zirconium dichloride, isopropylidene (4-methylcyclopentadienyl) (3-t-butylindenyl) zirconium dichloride, dimethylsilylene (2- Methyl-4-t-butyl-cyclopentadienyl) (3′-t-butyl-5′-methyl-cyclopentadienyl) zirconium dichloride, dimethylsilylenebis (indenyl) zirconium dichloride, dimethylsilylenebis (4,5 6,7-tetrahydroindenyl) zirconium dichloride, dimethylsilylene bis [1- (2-methyl-4-phenylindenyl)] zirconium dichloride, dimethylsilylene bis [1- (2-ethyl-4-phenylindenyl)] Zirconium dichloride, dimethylsilylenebis [4- (1-phenyl-3-methylindenyl)] zirconium dichloride, dimethylsilylene (fluorenyl) t-butylamidozirconium dichloride, methylphenylsilylenebis [1- (2-methyl-4, (1-naphthyl) -indenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-methyl-4,5-benzoindenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-methyl-4-phenyl-) 4H-azuleni ] Zirconium dichloride, dimethylsilylenebis [1- (2-ethyl-4- (4-chlorophenyl) -4H-azulenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-ethyl-4-naphthyl-4H-azurenyl) ] Zirconium dichloride, diphenylsilylene bis [1- (2-methyl-4- (4-chlorophenyl) -4H-azulenyl)] zirconium dichloride, dimethylsilylene bis [1- (2-ethyl-4- (3-fluorobiphenyl) Ryl) -4H-azurenyl)] zirconium dichloride, dimethylgermylenebis [1- (2-ethyl-4- (4-chlorophenyl) -4H-azurenyl)] zirconium dichloride, dimethylgermylenebis [1- (2-ethyl) -4-phenylindenyl)] zirconium di Zirconium compounds such as chloride can be exemplified.

In the above, compounds in which zirconium is replaced with titanium or hafnium can be used similarly. It is also preferable to use a mixture of a zirconium compound and a hafnium compound. In addition, the chloride can be replaced with other halogen compounds, hydrocarbon groups such as methyl, isobutyl and benzyl, amide groups such as dimethylamide and diethylamide, alkoxide groups such as methoxy group and phenoxy group, hydride groups and the like.
Of these, metallocene compounds obtained by crosslinking an indenyl group or an azulenyl group with silicon or a germyl group are particularly preferable.

The metallocene compound may be used by being supported on an inorganic or organic compound carrier. The carrier is preferably an inorganic or organic porous compound. Specifically, ion-exchange layered silicate, zeolite, SiO ₂ , Al ₂ O ₃ , silica alumina, MgO, ZrO ₂ , TiO ₂ , B Examples include inorganic compounds such as ₂ O ₃ , CaO, ZnO, BaO, and ThO ₂ , organic compounds composed of porous polyolefin, styrene / divinylbenzene copolymer, olefin / acrylic acid copolymer, and the like, or a mixture thereof. It is done.

  (Ii) As a co-catalyst that can be activated to a stable ionic state by reacting with a metallocene compound, an organoaluminum oxy compound (for example, an aluminoxane compound), an ion-exchange layered silicate, a Lewis acid, a boron-containing compound, an ionic compound Preferred examples include fluorine-containing organic compounds.

  (Iii) Examples of organoaluminum compounds include trialkylaluminum such as triethylaluminum, triisopropylaluminum, triisobutylaluminum, dialkylaluminum halide, alkylaluminum sesquihalide, alkylaluminum dihalide, alkylaluminum hydride, organoaluminum alkoxide. Preferably mentioned.

The production method of the propylene-based resin (Y) is not particularly limited, and can be produced by any of the conventionally known slurry polymerization method, bulk polymerization method, gas phase polymerization method, and the like. It is also possible to produce a polypropylene and a propylene random copolymer using a polymerization method.
Commercially available products include, for example, trade names “Novatech PP”, “Wintech”, “Newcon”, “Wellnex”, ExxonMobil trade names “Vista Max”, and Dow Chemical trade names. “Versify” and the like can be exemplified, and can be appropriately selected from these product groups and used alone or in combination.

[Proportion of polypropylene resin (X) and propylene resin (Y)]
The proportion of the polypropylene resin (X) and the propylene resin (Y) in the polypropylene resin composition for forming an inflation film of the present invention is based on a total of 100% by weight of (X) and (Y). (X) 1 to 30% by weight and propylene resin (Y) 70 to 99% by weight. By setting it as such a range, it can be set as the resin composition for inflation film shaping | molding which is excellent in the shaping | molding stability at the time of the film shaping | molding by an inflation method, and is excellent in transparency.
The preferred composition range is 2 to 30% by weight of component (X), 70 to 98% by weight of component (Y), and the more preferred range is 5 to 20% by weight of component (X) and 80 to 95% by weight of component (Y). %, Particularly preferred ranges are 5-15% by weight of component (X) and 85-95% by weight of component (Y).

[Other ingredients]
The polypropylene resin composition for forming an inflation film of the present invention is a resin composition containing the above-described polypropylene resin (X) and propylene resin (Y) as essential components, but does not impair the purpose of the present invention. Various other components such as other resins or additives can be added and used.

(1) Additive Additives such as an antioxidant that can be added to the propylene resin can be appropriately added to the polypropylene resin composition for forming an inflation film of the present invention as long as the effects of the present invention are not hindered.
Specifically, 2,6-di-t-butyl-p-cresol (BHT), tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane (BASF Japan) And trade name “IRGANOX 1010”) and n-octadecyl-3- (4′-hydroxy-3,5′-di-t-butylphenyl) propionate (trade name “IRGANOX 1076” manufactured by BASF Japan). Phenol stabilizers such as bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite and tris (2,4-di-t-butylphenyl) phosphite , Lubricants typified by higher fatty acid amides and higher fatty acid esters, glycerol esters and fatty acids of fatty acids having 8 to 22 carbon atoms Antistatic agents such as tannic acid esters and polyethylene glycol esters, sorbitol nucleating agents (for example, trade name “Gelol MD” manufactured by Shin Nippon Rika Co., Ltd.), aromatic phosphate esters (for example, trade name “NA- manufactured by ADEKA”) 21 ”), trade name“ Millad ”series manufactured by Milliken, brand name“ Hyperform ”produced by Milliken, nucleating agent represented by talc, high-density polyethylene, etc., blocking represented by silica, calcium carbonate, talc, etc. You may add the molecular weight modifier represented by an inhibitor, an organic peroxide, etc.

(2) Other polymers In addition, the polypropylene resin composition for forming an inflation film of the present invention is modified such as an elastomer and an alicyclic hydrocarbon resin that can be added to a propylene resin as long as the effects of the present invention are not hindered. Agents can be added as appropriate. The amount of the other polymer is not particularly limited as long as the effect of the present invention is not hindered, but is usually 100 parts by weight or less with respect to 100 parts by weight of the polypropylene resin composition for forming an inflation film of the present invention. .

  Specifically, an ethylene-α-olefin copolymer, for example, a low density polyethylene, a linear low density polyethylene, a high density polyethylene, a polyethylene resin represented by an ethylene elastomer, propylene and a carbon number of 4 to 12 Examples thereof include binary random copolymer resins with α-olefins and ternary random copolymer resins with propylene, ethylene and α-olefins having 4 to 12 carbon atoms. In addition, alicyclic hydrocarbon resins represented by petroleum resins, terpene resins, rosin resins, coumarone indene resins, and hydrogenated derivatives thereof may be added.

  Further, a styrene-based elastomer can be added, and the styrene-based elastomer can be appropriately selected from commercially available ones. For example, as a hydrogenated product of a styrene-butadiene block copolymer, Kraton “Clayton G” from Polymer Japan Co., Ltd., “Tough Tech” from Asahi Kasei Chemicals, Inc., “Septon” from Kuraray Co., Ltd. as a hydrogenated product of styrene-isoprene block copolymer. As a hydrogenated product of styrene-vinylated polyisoprene block copolymer, Kuraray Co., Ltd. under the trade name “Hibler”, and as a hydrogenated product of styrene-butadiene random copolymer, “Dynalon” from JSR Co., Ltd. It is sold under the product name, and it is used by appropriately selecting from these product groups. It may be.

[Production Method of Polypropylene Resin Composition]
The polypropylene resin composition for forming an inflation film of the present invention comprises the above-mentioned polypropylene resin (X) and the propylene resin (Y) and, if necessary, other additives and / or elastomers, a Henschel mixer, After mixing with a V blender, ribbon blender, tumbler blender or the like, it is obtained by a method of kneading with a kneader such as a single screw extruder, a multi-screw extruder, a kneader, or a Banbury mixer. As another form, the polypropylene resin (X) and the propylene resin (Y) are individually mixed with additives and / or elastomers using a Henschel mixer, V blender, ribbon blender, tumbler blender, etc. It can also be obtained as a pellet mixture obtained by kneading and pelletizing a kneader such as a single screw extruder, multi-screw extruder, kneader, Banbury mixer, etc. with a Henschel mixer, V blender, ribbon blender, tumbler blender, etc. . When an elastomer or other additive is used as an optional component, it can be added when obtaining the pellet mixture.

[Film forming method]
The method for film-forming the polypropylene resin composition for forming an inflation film of the present invention is an inflation method, preferably an air-cooled inflation method.
In a preferred embodiment of the air-cooled inflation method, the polypropylene resin composition for forming an inflation film of the present invention is melted by an extruder with an annular die, extruded into a tube shape, and air supplied from a blower or the like is melted from an air-cooling ring. This is a method in which the tube is blown onto a tube and cooled and solidified, and then folded with a pinch roll through a guide plate and taken up with a take-up machine. A molding machine, a cooling ring, a blower, a guide plate, a pinch roll, a film take-up machine, and the like that can be used in this molding method may be apparatuses widely used in the market, and no special ones are required.

  The conditions for molding the film by the air-cooled inflation method are not particularly limited, but the die diameter is usually φ50 mm to φ500 mm, the die lip width is usually 0.8 mm to 4.0 mm, and the molding temperature is usually 170 to 250 ° C., preferably 170 to 220 ° C., and the molding speed is usually 5 to 100 m / min, preferably 10 to 50 m / min.

  In addition, in the case of forming a multilayer film, the film is formed by an inflation method having a plurality of extruders and a co-extrusion multilayer annular die so that the polypropylene resin composition for forming an inflation film is disposed on at least one surface layer. It is a manufacturing method to obtain, Preferably it is the method used for the air cooling inflation method.

A preferred embodiment of the air-cooled inflation method for forming a multilayer film is a polypropylene-based resin composition for forming an inflation film of the present invention and a propylene-based resin or a resin constituting an ethylene-based resin layer by a plurality of extruders with a co-extrusion multilayer annular die. This is a method of melting and extruding into a tube shape, blowing air supplied from a blower or the like from an air-cooling ring to the melting tube to cool and solidify, folding it with a pinch roll through a guide plate, and taking it out with a take-up machine.
A molding machine, a cooling ring, a blower, a guide plate, a pinch roll, a film take-up machine, and the like that can be used at this time may be apparatuses widely used in the market, and no special ones are required. The conditions for forming the film by the air-cooled inflation method are not particularly limited, but the die diameter is usually φ50 mm to φ500 mm, the die lip width is usually 0.8 mm to 4.0 mm, and the molding temperature is usually 170 to 250 ° C., preferably 170 to 220 ° C., and the molding speed is usually 5 to 100 m / min, preferably 10 to 50 m / min.

  In the air-cooled inflation method, the tubular film can be formed by air cooling from the outside and / or the inside. The tube film blowing film forming method can employ any direction such as an upward method, a horizontal method, or a downward method, and the film forming method using the upward direction is particularly suitable for the polypropylene film for forming an inflation film of the present invention. Suitable for the composition.

  Examples of the inflation method other than the air-cooled inflation method include a water-cooled inflation method and a tubular biaxial stretching method, and these methods can be applied to produce a film.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
In addition, the polypropylene-type resin composition used in the Example and the comparative example, its component, the film formation stability by the inflation method, and various physical properties of the film were measured and evaluated according to the following evaluation methods.

[Physical properties of each propylene resin]
(1) Melt flow rate (MFR, unit: g / 10 minutes):
Measured in accordance with JIS K7210: 1999, Method A, Condition M (230 ° C., 2.16 kg load).
(2) 25 ° C. paraxylene soluble component amount (CXS, unit: wt%):
Measurement was performed according to the method described above.
(3) mm fraction (unit:%):
Using a superconducting nuclear magnetic resonance apparatus GSX-400 (400 MHz) manufactured by JEOL Ltd. and FT-NMR, as described above, measurement was performed by the method described in paragraphs [0053] to [0065] of JP-A-2009-275207. .

(4) Molecular weight distributions Mw / Mn and Mz / Mn:
It was determined by GPC measurement according to the method described above.
(5) Branch index g ′ when the absolute molecular weight Mabs is 1 million:
As described above, it was determined by GPC equipped with a differential refractometer (RI), a viscosity detector (Viscometer), and a light scattering detector (MALLS) as detectors.

(6) Melt tension MT (unit: grams):
It measured on the following conditions using the Toyo Seiki Seisakusho Capillograph.
・ Capillary: Diameter 2.0mm, length 40mm
・ Cylinder diameter: 9.55mm
・ Cylinder extrusion speed: 20 mm / min ・ Pickup speed: 4.0 m / min ・ Temperature: 230 ° C.
When the MT is extremely high, the resin may break at a take-up speed of 4.0 m / min. In such a case, the take-up speed is lowered and the tension at the highest speed at which the take-up can be taken is MT. And

(7) Degree of strain hardening λmax:
The extensional viscosity measurement was performed under the following conditions.
・ Device: Ares manufactured by Rheometrics
・ Jig: EXTENSIONAL VISUALITY FIXTURE, manufactured by TA Instruments
・ Measurement temperature: 180 ℃
-Strain rate: 0.1 / sec
-Preparation of test piece: A sheet of 18 mm x 10 mm and a thickness of 0.7 mm is formed by press molding.
The details of the method for calculating the strain hardening degree λmax (0.1) in the measurement of the extensional viscosity at a strain rate of 0.1 s ⁻¹ are as described above.

(8) Melting point (Tm, unit: ° C):
Using a differential operating calorimeter (DSC), once the temperature was raised to 200 ° C. and the heat history was erased, the temperature was lowered to 40 ° C. at a rate of 10 ° C./min, and again the temperature rising rate was 10 ° C./min. The temperature at the top of the endothermic peak was measured as the melting point (Tm).

[Shaping stability of film molding by inflation method]
Air-cooled inflation molding machine As an air-cooled inflation molding machine, a single-screw extruder with a screw diameter of 40 mm (hereinafter referred to as Ex1) for the outer layer, a single-screw extruder with a screw diameter of 40 mm (hereinafter referred to as Ex2) for the inner layer, and a screw for intermediate layer A three-layer air-cooled inflation molding machine equipped with a single-screw extruder (hereinafter referred to as Ex3) having a diameter of 50 mm, an HA300 type air ring manufactured by Plako Corporation, and a spiral type three-layer die having a diameter of 200 mm and a lip of 2 mm was used.

-Stability of film molding The polypropylene resin composition is charged into each of the Ex1, Ex2 and Ex3 extruders of the air-cooled inflation molding machine, the extruder temperature is 220 ° C, the die temperature is 230 ° C, and the total discharge amount is 30 kg / Extrusion is performed under the conditions of h, and an air-cooled inflation film having a substantially single layer structure is formed under conditions of a film folding width of 500 mm (blow ratio of 1.6) and a take-off speed of 40 m / min, and a thickness meter (manufactured by Mitutoyo Corporation). The film thickness was measured by Model ID-S112). Note that the blower memory is 30 Hz (the larger the value, the greater the amount of cooling air supplied from the air ring), and the guide roll was not used.
The bubble shaking state during molding under the above conditions was comparatively evaluated according to the following criteria.
○: The bubble hardly shakes.
Δ: Bubble slightly shakes.
X: The bubble shakes greatly.

[Measurement of film properties]
(1) Haze [Unit:%]:
The obtained film was conditioned for 24 hours or more in an atmosphere of 23 ° C. and 50% RH, and then measured with a haze meter in accordance with JIS K7136: 2000.
The smaller the value obtained, the better the transparency.
(2) Gross [Unit:%]:
The resulting film was conditioned for 24 hours or more in an atmosphere of 23 ° C. and 50% RH, and then measured at an incident angle of 20 ° in accordance with ASTM D2457-1970.

[Resin used]
<Polypropylene resin (X)>
As the polypropylene resin (X) used in Examples and Comparative Examples, pellets (X1) produced using the polypropylene resins (X-1) to (X-5) produced in Production Examples 1 to 5 described later. ~ (X6) was used.

[Production Example 1 (Production of polypropylene resin X-1)]
<Synthesis example 1 of catalyst component (A)>
rac-dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-i-propylphenyl) indenyl}] hafnium (component [A-1] (complex 1) Synthesis):
(I) Synthesis of 4- (4-i-propylphenyl) indene To a 500 ml glass reaction vessel, 15 g (91 mmol) of 4-i-propylphenylboronic acid and 200 ml of dimethoxyethane (DME) were added, and 90 g of cesium carbonate ( 0.28 mol) and 100 ml of water were added, 13 g (67 mmol) of 4-bromoindene and 5 g (4 mmol) of tetrakistriphenylphosphinopalladium were added in this order, and the mixture was heated at 80 ° C. for 6 hours.
After allowing to cool, the reaction solution was poured into 500 ml of distilled water, transferred to a separatory funnel, and extracted with diisopropyl ether. The ether layer was washed with saturated brine and dried over sodium sulfate. Sodium sulfate was filtered, the solvent was distilled off under reduced pressure, and the residue was purified by a silica gel column to obtain 15.4 g (yield 99%) of 4- (4-i-propylphenyl) indene as a colorless liquid.

(Ii) Synthesis of 2-bromo-4- (4-i-propylphenyl) indene In a 500 ml glass reaction vessel, 15.4 g (67 mmol) of 4- (4-i-propylphenyl) indene, 7.2 ml of distilled water DMSO: 200 ml was added, and 17 g (93 mmol) of N-bromosuccinimide was gradually added thereto. The mixture was stirred at room temperature for 2 hours, poured into 500 ml of ice water, and extracted three times with 100 ml of toluene. The toluene layer was washed with saturated brine, 2 g (11 mmol) of p-toluenesulfonic acid was added, and the mixture was heated to reflux for 3 hours while removing moisture. The reaction mixture was allowed to cool, washed with saturated brine, and dried over sodium sulfate. Sodium sulfate was filtered, the solvent was distilled off under reduced pressure, and the residue was purified with a silica gel column to obtain 19.8 g (yield 96%) of 2-bromo-4- (4-i-propylphenyl) indene as a yellow liquid. .

(Iii) Synthesis of 2- (2-methyl-5-furyl) -4- (4-i-propylphenyl) indene In a 500 ml glass reaction vessel, 6.7 g (82 ml mol) of 2-methylfuran, DME: 100 ml And cooled to -70 ° C in a dry ice-methanol bath. To this, 51 ml (81 mmol) of a 1.59 mol / L n-butyllithium-n-hexane solution was added dropwise and stirred as it was for 3 hours. The solution was cooled to −70 ° C., and a solution of 20 ml (87 mmol) of triisopropyl borate and 50 ml of DME was added dropwise thereto. After dropping, the mixture was stirred overnight while gradually returning to room temperature.
After the reaction solution was hydrolyzed with 50 ml of distilled water, a solution of 223 g of potassium carbonate and 100 ml of water and 19.8 mg (63 mmol) of 2-bromo-4- (4-i-propylphenyl) indene were added in this order, and the mixture was heated at 80 ° C. The mixture was heated and reacted for 3 hours while removing low-boiling components.
After allowing to cool, the reaction solution was poured into 300 ml of distilled water, transferred to a separatory funnel and extracted three times with diisopropyl ether. The ether layer was washed with saturated brine and dried over sodium sulfate. Sodium sulfate was filtered off, the solvent was distilled off under reduced pressure, and the residue was purified with a silica gel column to give 19.6 g of 2- (2-methyl-5-furyl) -4- (4-i-propylphenyl) indene colorless liquid Yield 99%).

(Iv) Synthesis of dimethylbis (2- (2-methyl-5-furyl) -4- (4-i-propylphenyl) indenyl) silane In a 500 ml glass reaction vessel, 2- (2-methyl-5- Furyl) -4- (4-i-propylphenyl) indene (9.1 g, 29 mmol) and THF (200 ml) were added, and the mixture was cooled to -70 ° C in a dry ice-methanol bath. To this, 17 ml (28 mmol) of a 1.66 mol / L n-butyllithium-hexane solution was dropped, and the mixture was stirred as it was for 3 hours. The mixture was cooled to −70 ° C., 0.1 ml (2 mmol) of 1-methylimidazole and 1.8 g (14 mmol) of dimethyldichlorosilane were sequentially added, and the mixture was stirred overnight while gradually returning to room temperature.
Distilled water was added to the reaction solution, transferred to a separatory funnel and washed with brine until neutral, and sodium sulfate was added to dry the reaction solution. Sodium sulfate was filtered, the solvent was distilled off under reduced pressure, and the residue was purified with a silica gel column, and dimethylbis (2- (2-methyl-5-furyl) -4- (4-i-propylphenyl) indenyl) silane pale 8.6 g (88% yield) of a yellow solid was obtained.

(V) Synthesis of dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-i-propylphenyl) indenyl}] hafnium In a 500 ml glass reaction vessel, 8.6 g (13 mmol) of dimethylbis (2- (2-methyl-5-furyl) -4- (4-i-propylphenyl) indenyl) silane and 300 ml of diethyl ether were added, and -70 ° C. in a dry ice-methanol bath. Until cooled. Thereto was added dropwise 15 ml (25 mmol) of a 1.66 mol / L n-butyllithium-n-hexane solution, and the mixture was stirred for 3 hours. The solvent of the reaction solution was distilled off under reduced pressure, 400 ml of toluene and 40 ml of diethyl ether were added, and the solution was cooled to −70 ° C. in a dry ice-methanol bath. Thereto was added 4.0 g (13 mmol) of hafnium tetrachloride. Thereafter, the mixture was stirred overnight while gradually returning to room temperature.
The solvent was distilled off under reduced pressure, recrystallized with dichloromethane-hexane, and dichloro [1,1′-dimethylsilylenebis {2- (5-methyl-2-furyl) -4- (4-i-propylphenyl) indenyl]. }] 7.6 g (yield 65%) of a hafnium racemate as yellow crystals was obtained.

The identified value by ^{1 H-NMR} of the obtained racemates are described below.
¹ H-NMR (C6D6) identification result:
Racemate: δ 0.95 (s, 6H), δ 1.10 (d, 12H), δ 2.08 (s, 6H), δ 2.67 (m, 2H), δ 5.80 (d, 2H), δ6. 37 (d, 2H), δ 6.74 (dd, 2H), δ 7.07 (d, 2H), δ 7.13 (d, 4H), δ 7.28 (s, 2H), δ 7.30 (d, 2H) ), Δ 7.83 (d, 4H).

<Synthesis example 2 of catalyst component (A)>
rac-dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4-hydroazurenyl}] hafnium (synthesis of component [A-2] (complex 2)):
The synthesis of rac-dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4-hydroazurenyl}] hafnium is carried out according to the method described in Example 1 of JP-A-11-240909. It carried out like.

<Catalyst synthesis example 1>
(I) Chemical treatment of ion-exchanged layered silicate In a separable flask, 96% sulfuric acid (668 g) was added to 2,264 g of distilled water, and then montmorillonite (made by Mizusawa Chemical Co., Ltd., trade name Benclay SL: average) as layered silicate 4 L) was added. The slurry was heated at 90 ° C. for 210 minutes. The reaction slurry was filtered after adding 4,000 g of distilled water to obtain 810 g of a cake-like solid.
Next, 432 g of lithium sulfate and 1,924 g of distilled water were added to the separable flask to make a lithium sulfate aqueous solution. The slurry was reacted at room temperature for 120 minutes. 4 L of distilled water was added to this slurry, followed by filtration, further washing with distilled water to pH 5-6, and filtration. As a result, 760 g of a cake-like solid was obtained.
The obtained solid was preliminarily dried overnight at 100 ° C. under a nitrogen stream, and then coarse particles of 53 μm or more were removed and further dried at 200 ° C. for 2 hours under reduced pressure to obtain 220 g of chemically treated montmorillonite.
The composition of this chemically treated montmorillonite is Al: 6.45 wt%, Si: 38.30 wt%, Mg: 0.98 wt%, Fe: 1.88 wt%, Li: 0.16 wt%, Al / Si = 0.175 [mol / mol].

(Ii) Catalyst preparation and prepolymerization In a three-necked flask (volume: 1 L), 20 g of the chemically treated montmorillonite obtained above was added, and heptane (132 mL) was added to form a slurry, which was triisobutylaluminum (25 mmol: concentration) 143 mg / mL heptane solution (68.0 mL) was added, and the mixture was stirred for 1 hour, washed with heptane until the residual liquid ratio became 1/100, and heptane was added so that the total volume became 100 mL.
In another flask (volume: 200 mL), complex 1 of the catalyst component [A-1] prepared in Synthesis Example 1 of the catalyst component (A), rac-dichloro [1,1′-dimethylsilylenebis { 2- (5-methyl-2-furyl) -4- (4-i-propylphenyl) indenyl}] hafnium (210 μmol) was dissolved in toluene (42 mL) (solution 1), and another flask (volume 200 mL) was added. ), The catalyst component [A-2] complex 2 prepared in Synthesis Example 2 of the catalyst component (A), rac-dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4) -Chlorophenyl) -4-hydroazurenyl}] hafnium (90 μmol) was dissolved in toluene (18 mL) (solution 2).

Triisobutylaluminum (0.84 mmol: 1.2 mL of a heptane solution with a concentration of 143 mg / mL) was added to a 1 L flask containing the previously chemically treated montmorillonite, and then the above solution 1 was added and stirred at room temperature for 20 minutes. Thereafter, triisobutylaluminum (0.36 mmol: 0.50 mL of a heptane solution having a concentration of 143 mg / mL) was added, and then the above solution 2 was added and stirred at room temperature for 1 hour.
Thereafter, 338 mL of heptane was added, and this slurry was introduced into a 1 L autoclave.
After the internal temperature of the autoclave was set to 40 ° C., propylene was fed at a rate of 10 g / hour, and prepolymerization was performed while maintaining the temperature at 40 ° C. for 4 hours. Thereafter, propylene feed was stopped and residual polymerization was carried out for 1 hour. After removing the supernatant of the resulting catalyst slurry by decantation, triisobutylaluminum (12 mmol: 17.0 mL of a heptane solution having a concentration of 143 mg / mL) was added to the remaining portion and stirred for 5 minutes.
This solid was dried under reduced pressure for 1 hour to obtain 56.4 g of a dry prepolymerized catalyst. The prepolymerization ratio (value obtained by dividing the amount of prepolymerized polymer by the amount of solid catalyst) was 1.82.
Hereinafter, this is referred to as “preliminary polymerization catalyst 1”.

<Polymerization>
After sufficiently replacing the inside of the stirring autoclave having an internal volume of 200 liters with propylene, 45 kg of sufficiently dehydrated liquefied propylene was introduced. Hydrogen 7.3NL (0.65 g) and triisobutylaluminum (0.12 mol: 0.47 L of a heptane solution with a concentration of 50 g / L) were added thereto, and the internal temperature was raised to 70 ° C. Next, 2.4 g of the prepolymerized catalyst 1 (by weight excluding the prepolymerized polymer) was injected with argon to initiate polymerization, and the internal temperature was maintained at 70 ° C. After 2 hours, 100 ml of ethanol was injected, purged of unreacted propylene, and the inside of the autoclave was purged with nitrogen to terminate the polymerization.
The obtained polymer was dried for 1 hour under a nitrogen stream at 90 ° C. to obtain 18.2 kg of a propylene polymer (hereinafter referred to as “polypropylene resin X-1”).
The catalytic activity was 7600 (g-PP / g-cat).

[Production Example 2 (Production of polypropylene resin X-2)]
<Polymerization>
After sufficiently replacing the inside of the stirring autoclave having an internal volume of 200 liters with propylene, 45 kg of sufficiently dehydrated liquefied propylene was introduced. Hydrogen 9.2NL (0.82 g) and triisobutylaluminum (0.12 mol: 0.47 L of a heptane solution with a concentration of 50 g / L) were added thereto, and the internal temperature was raised to 70 ° C.
Next, 2.1 g (by weight excluding the prepolymerized polymer) of the prepolymerized catalyst 1 used in Production Example 1 was injected with argon to initiate polymerization, and the internal temperature was maintained at 70 ° C. After 2 hours, 100 ml of ethanol was injected, purged of unreacted propylene, and the inside of the autoclave was purged with nitrogen to terminate the polymerization.
The obtained polymer was dried at 90 ° C. under a nitrogen stream for 1 hour to obtain 18.8 kg of a propylene polymer (hereinafter referred to as “polypropylene resin X-2”).
The catalytic activity was 9000 g PP / g catalyst.

[Production Example 3 (Production of polypropylene resin X-3)]
<Polymerization>
After sufficiently replacing the inside of the stirring autoclave having an internal volume of 200 liters with propylene, 45 kg of sufficiently dehydrated liquefied propylene was introduced. To this, 7.0 NL (0.63 g) of hydrogen and 0.54 kg of ethylene were added, and triisobutylaluminum (0.12 mol: 0.47 L of a heptane solution having a concentration of 50 g / L) was added. The temperature was raised to ° C.
Next, 1.9 g of the prepolymerized catalyst 1 (by weight excluding the prepolymerized polymer) was injected with argon to initiate polymerization, and the internal temperature was maintained at 70 ° C. After 2 hours, 100 ml of ethanol was injected under pressure, unreacted monomers were purged, and the autoclave was purged with nitrogen to terminate the polymerization.
The obtained polymer was dried at 90 ° C. under a nitrogen stream for 1 hour to obtain 22.3 kg of a polymer (hereinafter referred to as “polypropylene resin X-3”).
The catalytic activity was 11700 g PP / g catalyst. The ethylene content in the polymer was 0.92 wt%.

[Production Example 4 (Production of polypropylene resin X-4)]
<Polymerization>
After sufficiently replacing the inside of the stirring autoclave having an internal volume of 200 liters with propylene, 45 kg of sufficiently dehydrated liquefied propylene was introduced. To this was added 6.0 NL (0.54 g) of hydrogen and 2.27 kg of ethylene, and triisobutylaluminum (0.12 mol: 0.47 L of a heptane solution having a concentration of 50 g / L) was added. The temperature was raised to.
Next, 0.76 g of the prepolymerized catalyst 1 (by weight excluding the prepolymerized polymer) was injected with argon to initiate polymerization, and the internal temperature was maintained at 65 ° C. After 2 hours, 100 ml of ethanol was injected under pressure, unreacted monomers were purged, and the autoclave was purged with nitrogen to terminate the polymerization.
The obtained polymer was dried at 90 ° C. under a nitrogen stream for 1 hour to obtain 18.9 kg of a polymer (hereinafter referred to as “polypropylene resin X-4”).
The catalytic activity was 24900 g PP / g catalyst. The ethylene content in the polymer was 2.87 wt%.

[Production Example 5 (Production of polypropylene resin X-5)]
<Polymerization>
After sufficiently replacing the inside of the stirring autoclave having an internal volume of 200 liters with propylene, 45 kg of sufficiently dehydrated liquefied propylene was introduced. To this was added 2.8 NL (0.25 g) of hydrogen and 2.27 kg of ethylene, and triisobutylaluminum (0.12 mol: 0.47 L of a heptane solution having a concentration of 50 g / L) was added. The temperature was raised to.
Next, 0.82 g of the prepolymerized catalyst 1 (by weight excluding the prepolymerized polymer) was injected with argon to initiate polymerization, and the internal temperature was maintained at 65 ° C. After 2 hours, 100 ml of ethanol was injected under pressure, unreacted monomers were purged, and the autoclave was purged with nitrogen to terminate the polymerization.
The obtained polymer was dried at 90 ° C. under a nitrogen stream for 1 hour to obtain 16.8 kg of a polymer (hereinafter referred to as “polypropylene resin X-5”).
The catalytic activity was 20500 g PP / g catalyst. The ethylene content in the polymer was 2.86 wt%.

[Production of Pellets (X1) to (X2) of Polypropylene Resin X-1 to X-2]
Tetrakis [methylene-3- (3 ′, 5 ′), which is a phenolic antioxidant, with respect to 100 parts by weight of the polypropylene resins (X-1) to (X-2) produced in Production Examples 1 and 2 above. -Di-t-butyl-4′-hydroxyphenyl) propionate] methane (trade name “IRGANOX1010”, manufactured by BASF Japan Ltd.) 0.125 parts by weight, Tris (2,4) as a phosphite antioxidant -Di-t-butylphenyl) phosphite (trade name “IRGAFOS 168”, manufactured by BASF Japan Ltd.) 0.125 parts by weight, and using a high-speed stirring mixer (Henschel mixer, trade name) at room temperature After mixing for 3 minutes, the mixture was melt-kneaded with a twin-screw extruder to obtain polypropylene resin (X) pellets (X1) to (X2).
For the twin screw extruder, KZW-25 manufactured by Technobel was used, the screw rotation speed was 400 RPM, and the kneading temperature was 80, 160, 210, 230 from the bottom of the hopper (hereinafter, the same temperature up to the die outlet). did.

[Production of polypropylene resin pellets (X3)]
Tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] with respect to 100 parts by weight of the polypropylene resin (X-1) produced in Production Example 1 above. 0.125 parts by weight of methane (“IRGANOX1010”), 0.125 parts by weight of tris (2,4-di-t-butylphenyl) phosphite (“IRGAFOS 168), di (2-t-butyl) which is a peroxide Peroxyisopropyl) benzene (trade name “Perbutyl P-40”, manufactured by NOF Corporation) 0.035 parts by weight is blended and mixed at room temperature for 3 minutes using a high-speed agitating mixer (Henschel mixer, trade name). After that, melt-kneading was performed with a twin-screw extruder to obtain polypropylene resin (X) pellets (X3).
For the twin-screw extruder, KZW-25 manufactured by Technobel was used in the same manner as the production of the pellets (X1) to (X2), the screw rotation speed was 400 RPM, and the kneading temperature was 80, 160 from the bottom of the hopper. 210 and 230 (hereinafter, the same temperature up to the die outlet) was set to ° C.

[Production of Pellets (X4) to (X6) of Polypropylene Resin X-3 to X-5]
Tetrakis [methylene-3- (3 ′, 5 ′), which is a phenolic antioxidant, with respect to 100 parts by weight of the polypropylene resins (X-3) to (X-5) produced in Production Examples 3 to 5 above. -Di-t-butyl-4′-hydroxyphenyl) propionate] methane (trade name “IRGANOX1010”, manufactured by BASF Japan Ltd.) 0.125 parts by weight, Tris (2,4) as a phosphite antioxidant -Di-t-butylphenyl) phosphite (trade name "IRGAFOS 168", manufactured by BASF Japan Ltd.) 0.125 parts by weight, and using a high-speed stirring mixer (Henschel mixer, trade name) at room temperature After mixing for 3 minutes, the mixture was melt-kneaded with a twin-screw extruder to obtain polypropylene resin (X) pellets (X4) to (X6).
For the twin screw extruder, KZW-25 manufactured by Technobel was used, the screw rotation speed was 400 RPM, and the kneading temperature was 80, 160, 210, 230 from the bottom of the hopper (hereinafter, the same temperature up to the die outlet). did.

These pellets (X1) to (X6) were subjected to various evaluations described above.
The evaluation results are shown in Table 1.

Moreover, the following commercially available polypropylene resin Z1 and Z2 were used as what does not correspond to polypropylene resin (X).
Z1; manufactured by Basel, trade name “PF814” (high melt tension polypropylene by electron beam irradiation)
Z2; manufactured by Nippon Polypro Co., Ltd., trade name “NOVATEC (registered trademark) FY6H” (propylene homopolymer with Ziegler-Natta catalyst)
The characteristics of Z1 and Z2 are shown in Table 1.

<Propylene-based resin (Y)>
The following commercially available propylene / ethylene random copolymers (Y1) to (Y2) were used as the propylene resin (Y).
Y1; manufactured by Nippon Polypro Co., Ltd., trade name “Wintech (registered trademark) WFX4TA” (propylene / ethylene random copolymer with metallocene catalyst, MFR = 7 g / 10 min, Tm = 125 ° C., MT = 0.3 g, Mw / Mn = 2.5)
Y2: manufactured by Nippon Polypro Co., Ltd., trade name “Wintech (registered trademark) WFW5T” (propylene / ethylene random copolymer with metallocene catalyst, MFR = 3.5 g / 10 min, Tm = 143 ° C., MT = 0. 7 g, Mw / Mn = 2.8)

[Example 1]
A pellet mixture composed of 2.5% by weight of the pellet (X1) obtained in the above production example as the polypropylene resin (X) and 97.5% by weight of (Y1) as the propylene resin (Y) was obtained using a twin screw extruder. Polypropylene resin composition for forming an inflation film by melting and mixing, taking out the molten resin extruded from the strand die while cooling and solidifying in a cooling water tank, and cutting the strand into a diameter of about 3 mm and a length of about 2 mm using a strand cutter Product pellets were obtained.
The twin-screw extruder used was KZW-25 manufactured by Technobel, the screw rotation speed was 400 RPM, the discharge rate was 20 kg / h, and the kneading temperature was 80, 160, 210, 230 from the bottom of the hopper to the die outlet. Same temperature) ° C setting.
Using the obtained polypropylene-based resin composition pellet for forming an inflation film, film formation was performed by the method described above.
Table 2 shows the physical property evaluation results of the obtained film.

[Example 2]
A film was prepared in the same manner as in Example 1 except that the pellet (X1) of the polypropylene resin (X) was 5% by weight and the pellet (Y1) of the propylene resin (Y) was 95% by weight. Molding was performed.
Table 2 shows the physical property evaluation results of the obtained film.

[Example 3]
A film was prepared in the same manner as in Example 1, except that the pellet (X1) of polypropylene resin (X) was changed to 10% by weight and the pellet (Y1) of propylene resin (Y) was changed to 90% by weight. Molding was performed.
Table 2 shows the physical property evaluation results of the obtained film.

[Comparative Example 1]
Using only the propylene-based resin (Y) pellets (Y1), film formation was performed by the method described above.
The evaluation results are shown in Table 2.
Since the polypropylene resin (X) according to the present invention was not added, the bubbles were greatly shaken and the film forming stability was poor.

[Comparative Example 2]
In Example 3, film formation was performed in the same manner as in Example 3 except that Z1 was used instead of the pellet (X1) of the polypropylene resin (X).
Table 2 shows the physical property evaluation results of the obtained film.
Since polypropylene resins other than the polypropylene resin (X) according to the present invention were added, the film forming stability was excellent, but the transparency was greatly deteriorated.

[Comparative Example 3]
In Example 3, film forming was performed in the same manner as in Example 3 except that Z2 was used instead of the polypropylene resin (X) pellet (X1).
Table 2 shows the physical property evaluation results of the obtained film.
Since a polypropylene resin other than the polypropylene resin (X) according to the present invention was added, the bubbles were greatly shaken and the film forming stability was poor.

[Comparative Example 4]
In film formation of Comparative Example 2, film formation was performed in the same manner as in Comparative Example 2, except that the take-up speed was changed from 40 m / min to 18.5 m / min.
Table 2 shows the physical property evaluation results of the obtained film.
Since polypropylene resins other than the polypropylene resin (X) according to the present invention were added, the transparency of the film was greatly deteriorated.

[Reference Example 1]
In film formation of Comparative Example 1, film formation was performed in the same manner as Comparative Example 1 except that the take-up speed was changed from 40 m / min to 18.5 m / min.
Table 2 shows the physical property evaluation results of the obtained film.
Since the take-up speed of the film was low, the molding stability was excellent and the transparency of the film was good even without adding the polypropylene resin (X) according to the present invention.

[Example 4]
In Example 3, film forming was performed in the same manner as in Example 3 except that (X2) was used instead of the pellet (X1) of the polypropylene resin (X).
Table 3 shows the physical property evaluation results of the obtained film.

[Example 5]
In Example 3, film forming was performed in the same manner as in Example 3 except that (X3) was used instead of the polypropylene resin (X) pellet (X1).
Table 3 shows the physical property evaluation results of the obtained film.

[Example 6]
In Example 3, film forming was performed in the same manner as in Example 3 except that (Y2) was used instead of the pellet (Y1) of the propylene-based resin (Y).
Table 3 shows the physical property evaluation results of the obtained film.

[Example 7]
In the air-cooled inflation molding machine described above, the propylene resin (Y1) was used for Ex1 for the outer layer and Ex2 for the inner layer, and the polypropylene resin composition pellets for molding an inflation film used in Example 3 for Ex3 for the intermediate layer (X1: 10% by weight, Y1: 90% by weight), extruder temperature 220 ° C., die temperature 230 ° C., Ex1 discharge rate 7.5 kg / h, Ex2 discharge rate 7.5 kg / h, Ex3 discharge Extrusion was performed under the condition that the amount was 15 kg / h, and an air-cooled blown film having two layers and three layers was formed under conditions of a film folding width of 500 mm (blowing ratio of 1.6) and a take-off speed of 40 m / min.
The blower memory was 30 Hz (the larger the value, the greater the amount of cooling air supplied from the air ring), and no guide roll was used.
Table 4 shows the physical property evaluation results of the obtained film.

[Example 8]
In Example 7, it was carried out except that the polypropylene resin composition pellets for forming an inflation film used in Example 4 (X2: 10% by weight, Y1: 90% by weight) were added to Ex3 of the air-cooled inflation molding machine. A film was formed in the same manner as in Example 7.
Table 4 shows the physical property evaluation results of the obtained film.

[Example 9]
In Example 7, except that the polypropylene resin composition pellets (X3: 10% by weight, Y1: 90% by weight) used in Example 5 were added to Ex3 of the air-cooled inflation molding machine. A film was formed in the same manner as in Example 7.
Table 4 shows the physical property evaluation results of the obtained film.

[Example 10]
In Example 7, film forming was performed in the same manner as in Example 7 except that the take-up speed was 18.5 m / min.
Table 4 shows the physical property evaluation results of the obtained film.

[Example 11]
In the film formation of Example 3, film formation was performed in the same manner as in Example 3 except that the take-up speed was changed from 40 m / min to 18.5 m / min.
Table 5 shows the physical property evaluation results of the obtained film.

[Example 12]
In film formation of Example 4, film formation was performed in the same manner as in Example 4 except that the take-up speed was changed from 40 m / min to 18.5 m / min.
Table 5 shows the physical property evaluation results of the obtained film.

[Example 13]
In film formation of Example 5, film formation was performed in the same manner as in Example 5 except that the take-up speed was changed from 40 m / min to 18.5 m / min.
Table 5 shows the physical property evaluation results of the obtained film.

[Example 14]
In Example 2, film molding was performed in the same manner as in Example 2 except that (X4) was used instead of the pellet (X1) of the polypropylene resin (X).
Table 5 shows the physical property evaluation results of the obtained film.

[Example 15]
In Example 3, film forming was performed in the same manner as in Example 3 except that (X4) was used instead of the pellet (X1) of the polypropylene resin (X).
Table 5 shows the physical property evaluation results of the obtained film.

[Example 16]
In the film formation of Example 15, film formation was performed in the same manner as in Example 15 except that the take-up speed was changed from 40 m / min to 18.5 m / min.
Table 5 shows the physical property evaluation results of the obtained film.

[Example 17]
In Example 3, film molding was performed in the same manner as in Example 3 except that (X5) was used instead of the pellet (X1) of the polypropylene resin (X).
Table 5 shows the physical property evaluation results of the obtained film.

[Example 18]
In the film forming of Example 17, film forming was performed in the same manner as in Example 17 except that the take-up speed was changed from 40 m / min to 18.5 m / min.
Table 5 shows the physical property evaluation results of the obtained film.

[Example 19]
In Example 3, film forming was performed in the same manner as in Example 3 except that (X6) was used instead of the pellet (X1) of the polypropylene resin (X).
Table 5 shows the physical property evaluation results of the obtained film.

[Example 20]
In the film formation of Example 19, film formation was performed in the same manner as in Example 19 except that the take-up speed was changed from 40 m / min to 18.5 m / min.
Table 5 shows the physical property evaluation results of the obtained film.

  As is apparent from the physical property evaluation results of the films of Tables 2 to 5, the polypropylene resin compositions for forming the inflation film of Examples 1 to 20 were excellent in molding stability and obtained in the film molding by the inflation method. The film is excellent in transparency.

  The polypropylene-based resin composition for forming an inflation film of the present invention is excellent in molding stability in film formation by an inflation method, and the obtained film is excellent in transparency. Industrial applicability is very high.

Claims (5)

1 to 30% by weight of a polypropylene resin (X) having a branched structure that satisfies the following characteristics (i) to (iii), and does not correspond to the polypropylene resin (X), and has the following characteristics (a) propylene resin (Y) 70 to 99 wt% Tona is, inflation film molding polypropylene resin composition which is characterized by not blended foaming agent satisfying.
(I) MFR is 0.1-30 g / 10min.
(Ii) The branching index g ′ when the absolute molecular weight Mabs is 1 million is 0.55 or more and less than 1.00.
(Iii) Melt tension (MT) (unit: g) is
log (MT) ≧ −0.9 × log (MFR) +0.7 or MT ≧ 15
Satisfy one of the following.
(A) MFR is 0.1-20 g / 10min.   The polypropylene resin composition for forming an inflation film according to claim 1, wherein the propylene resin (Y) is a propylene / α-olefin copolymer having a melting point of 110 to 155 ° C.   The polypropylene-based resin composition for forming an inflation film according to claim 1 or 2, wherein the propylene resin (Y) is a propylene / ethylene copolymer polymerized using a metallocene catalyst.   A method for producing a film, comprising using the polypropylene resin composition for forming an inflation film according to any one of claims 1 to 3 to form a film by an inflation method.   The film production method according to claim 4, wherein the inflation method is an air-cooled inflation method.