JP4797288B2 - Polypropylene resin composition and method for producing T-die film - Google Patents

Description

【００５０】
【発明の効果】
以上、詳述したように本発明によれば、高速でのＴダイフィルム製膜時においても得られるフィルムの透明性、外観およびＭＤ方向の引裂強度のバランスに優れるフィルムが得られるポリプロピレン系樹脂およびそれからなるフィルム、並びに高速でのＴダイフィルム製膜時においても透明性、外観およびＭＤ方向の引裂強度のバランスに優れるＴダイフィルムの製造方法が提供される。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polypropylene resin composition for forming a high-speed T-die film and a method for producing a T-die film.
[0002]
[Prior art]
Polypropylene films are widely used in packaging fields such as food packaging and fiber packaging because of their excellent optical properties, mechanical properties, and packaging suitability. In recent years, high-speed film forming machines have been accelerated to improve film productivity, but in this case, deterioration of film cooling efficiency and increase in orientation in the MD direction (longitudinal direction during film formation) occur. As a result, the transparency and appearance of the resulting film deteriorated, and the tear strength in the MD direction has deteriorated.
[0003]
[Problems to be solved by the invention]
For example, a polypropylene resin having a relatively wide molecular weight distribution and a large die swell ratio has a small deterioration in transparency and appearance of a film obtained even when the film is formed at high speed, but the tear strength in the MD direction is deteriorated. On the other hand, a polypropylene resin having a relatively narrow molecular weight distribution and a small die swell ratio has little deterioration in the tear strength in the MD direction of the film obtained even during high-speed film formation, but the transparency deteriorates on the film surface. The appearance of the film deteriorates due to adhesion of touch roll marks. Under such circumstances, the problem to be solved by the present invention is a high-speed T-die film from which a film excellent in the balance of transparency, appearance and tear strength in the MD direction can be obtained at the time of forming a high-speed T-die film. An object of the present invention is to provide a method for producing a T-die film that is excellent in the balance of transparency, appearance, and tear strength in the MD direction when forming a polypropylene resin for film formation and a T-die film at high speed.
[0004]
[Means for Solving the Problems]
The present invention is a polypropylene resin composition for processing a T-die film at a film forming speed of 130 to 1000 m / min, and the molecular weight distribution measured for the T-die film obtained by forming the T-die film is A polypropylene resin composition having a die swell ratio of 4.28 or less and a die swell ratio of 1.28 or more, and a polypropylene resin composition for processing a T-die film at a film forming speed of 130 to 1000 m / min, A polypropylene resin composition comprising 100 parts by weight of a propylene polymer resin (A) having a ratio of less than 1.70 and 0.01 to 45 parts by weight of a propylene polymer resin (B) having a die swell ratio of 1.80 or more. is there. The present invention also relates to a method for producing a T-die film that uses these polypropylene resin compositions and processes a T-die film at a film forming speed of 130 to 1000 m / min.
Hereinafter, the present invention will be described in more detail.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The polypropylene resin composition of the present invention is a polypropylene resin composition having a molecular weight distribution of 4.2 or less and a die swell ratio of 1.28 or more measured using a T die film obtained by forming the T die film as a sample. It is a resin composition, and is excellent in the balance of transparency, appearance, and tear strength in the MD direction of the obtained film when forming a T-die film at high speed. The molecular weight distribution is preferably 1.0 to 4.0, and the die swell ratio is preferably 1.30 to 2.00.
As the die swell ratio here, the diameter of the cross section of the extrudate at the time of melt flow rate (MFR) measurement according to the method of condition 14 of JIS K7210 is measured, and a value determined from the following equation is adopted.
Die swell ratio = Extrudate cross section diameter / Orifice diameter
However, the cross section of the extrudate means a cross section perpendicular to the extruding direction of the extrudate, and when the cross section is not a true circle, the average value of the maximum value and the minimum value of the diameter of the cross section is the cross section of the extrudate. The diameter of
The molecular weight distribution referred to here is G. P. C. The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by (gel permeation chromatography) is employed.
[0006]
Such a polypropylene resin composition can be obtained, for example, by blending a propylene polymer resin having a small die swell ratio and a propylene polymer resin having a large die swell ratio. More specifically, the polypropylene resin composition is more preferably 100 parts by weight of a propylene polymer resin (A) having a die swell ratio of less than 1.70 and a propylene polymer resin (B) of 0.01 having a die swell ratio of 1.80 or more. It is said polypropylene resin composition which consists of -45 weight part.
[0007]
The second polypropylene resin composition of the present invention comprises a propylene polymer resin (A) of 100 parts by weight with a die swell ratio of less than 1.70 and a propylene polymer resin (B) of 0.01 with a die swell ratio of 1.80 or more. It is a polypropylene resin composition comprising ˜45 parts by weight, and is excellent in the balance of transparency, appearance, and tear strength in the MD direction of the obtained film when a T-die film is formed at high speed.
[0008]
When the die swell ratio of the propylene polymer resin (A) is in the above range, the tear strength in the MD direction of the film obtained at the time of T-die film formation at high speed is excellent, which is preferable. The die swell ratio of the propylene polymer resin (A) is preferably 1.00 to 1.60, more preferably 1.05 to 1.50, and even more preferably 1.10 to 1.35. .
[0009]
On the other hand, when the die swell ratio of the propylene polymer resin (B) is in the above range, the transparency and appearance of the film obtained at the time of T-die film formation at high speed are excellent, which is preferable. The die swell ratio of the propylene polymer resin (B) is more preferably 1.80 to 3.00, and still more preferably 2.00 to 3.00.
[0010]
When the amount of the propylene polymer resin (B) is in the above range, the tear strength, transparency and appearance in the MD direction of the film obtained at the time of T-die film formation at high speed are excellent and preferable. The amount of the propylene polymer resin (B) is preferably 0.01 to 30 parts by weight, more preferably 0.10 to 20 parts by weight with respect to 100 parts by weight of the propylene polymer resin (A). More preferably, it is 0.20 to 15 parts by weight.
[0011]
The propylene polymer resin (A) is a propylene homopolymer resin, or a copolymer resin of propylene and an α-olefin having 2 to 12 carbon atoms other than propylene and the like that does not lose crystallinity, and those A plurality of resins selected from the above are preferable. Examples of the α-olefin include ethylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene and the like. The copolymerization is performed for the purpose of controlling flexibility and impact resistance, and the content of the repeating unit derived from a monomer other than propylene is 10% by weight or less in the case of ethylene and 4 to 12 carbon atoms. In the case of the α-olefin, 30% by weight or less is preferable. Among these, from a homopolymer resin of propylene, a random copolymer resin of propylene and ethylene having a repeating unit content derived from ethylene of 10% by weight or less, an α-olefin having 4 to 12 carbon atoms Random copolymer resin of propylene and α-olefin having 4 to 12 carbon atoms, wherein the content of repeating units derived is 30% by weight or less, and the content of repeating units derived from ethylene is 10% by weight or less A ternary random copolymer resin of propylene, ethylene, and an α-olefin having 4 to 12 carbon atoms, wherein the content of repeating units derived from the α-olefin having 4 to 12 carbon atoms is 30% by weight or less Or, a block copolymer resin of propylene and ethylene is more preferably used. In this case, 1-butene is particularly preferable as the α-olefin.
[0012]
The method for producing the propylene polymer resin (A) is not particularly limited, and examples thereof include a gas phase polymerization method and a solvent polymerization method, and the gas phase polymerization method is particularly preferable. As the catalyst used for the polymerization, various known catalysts can be used. Preferably, the catalyst is obtained by using a multisite catalyst obtained by using a solid catalyst component containing a titanium atom, a magnesium atom and a halogen atom, or a metallocene complex. Single site catalyst.
[0013]
As the propylene polymer resin (B), various known propylene polymer resins can be used. For example, a non-linear propylene polymer resin having strain-hardening elongational viscosity or a wide range produced by multistage polymerization. Examples include propylene polymer resins having a molecular weight distribution.
[0014]
As the propylene polymer resin (B), the following propylene polymer (C) is preferably used.
Propylene polymer (C): a step of producing a crystalline propylene polymer portion (a) having an intrinsic viscosity of 5.0 dl / g or more and a crystalline propylene polymer portion (b) having an intrinsic viscosity of less than 3.0 dl / g The proportion of the crystalline propylene polymer portion (a) in the whole resin is 0.05 to 35% by weight, and the intrinsic viscosity of the whole resin is less than 3.0 dl / g. And a propylene polymer having a molecular weight distribution of less than 10.
As a specific production method of the propylene polymer (C), for example, (a) is polymerized in the first stage, and then (b) is polymerized in the same polymerization tank as (a) is polymerized in the second stage. A batch polymerization method for polymerization and two or more polymerization tanks are arranged in series, and as a first stage (a), the product after polymerization is transferred to the next polymerization tank, and in the polymerization tank as a second stage ( Examples thereof include a continuous polymerization method for polymerizing b). In the case of the continuous polymerization method, the polymerization tanks in the first stage and the second stage may be one tank or two or more tanks.
[0015]
The intrinsic viscosity of the crystalline propylene polymer portion (a) is 5.0 dl / g or more, preferably 6.0 dl / g or more. Within this range, the transparency and appearance improvement effect of the film made of the polypropylene resin composition of the present invention are preferably increased. The intrinsic viscosity of (a) is preferably as high as possible, but the upper limit is not particularly limited, but is usually less than 15.0 dl / g. The intrinsic viscosity of (a) is more preferably 6.0 to 13.0 dl / g, and further preferably 7.0 to 11.0 dl / g.
[0016]
The proportion of the crystalline propylene polymer portion (a) in the propylene polymer (C) is 0.05 to 35% by weight, preferably 0.1 to 25% by weight, more preferably 0.3 to 18% by weight. It is. If it is in this range, the die swell ratio when used as a composition is easily set in a suitable range, which is preferable.
[0017]
The intrinsic viscosity of the crystalline propylene polymer portion (b) is less than 3.0 dl / g, preferably 2.0 dl / g or less. Within this range, the polypropylene resin composition of the present invention is excellent in fluidity and processability and is preferred. The intrinsic viscosity of (b) is preferably as low as possible, but the lower limit is not particularly limited, but is usually 0.5 dl / g or more.
The intrinsic viscosity of (b) is more preferably 0.8 to 2.0 dl / g, still more preferably 1.0 to 1.8 dl / g.
[0018]
The intrinsic viscosity of (b) can be set within the above range by appropriately setting the production conditions of (b). In the case of propylene polymer (C) composed of (a) and (b), the intrinsic viscosity of the finally obtained propylene polymer (C) [η ]_C And the intrinsic viscosity [η] of (a)_a And the intrinsic viscosity [η] of (b) from the content ratio (% by weight) in (C) of each of (a) and (b) according to the following formula 1._b Ask for.
[Η]_b   = ([Η]_C × 100- [η]_a × W_a ) ÷ W_b       [Formula 1]
[Η]_C : Intrinsic viscosity (dl / g) of propylene polymer (C)
[Η]_a : Intrinsic viscosity (dl / g) of crystalline propylene polymer part (a)
W_a   : Content (% by weight) of crystalline propylene polymer portion (a)
W_b   : Content (% by weight) of crystalline propylene polymer part (b)
[0019]
The intrinsic viscosity of the entire propylene polymer (C) is less than 3.0 dl / g. Within this range, the polypropylene resin composition of the present invention is excellent in fluidity and processability and is preferred. The intrinsic viscosity of the (C) is preferably as low as possible, but the lower limit is not particularly limited, but is usually 1.0 dl / g or more. The intrinsic viscosity of (C) is more preferably 1.0 dl / g or more and less than 3.0 dl / g, and further preferably 1.2 dl / g or more and less than 2.8 dl / g.
[0020]
The overall molecular weight distribution of the propylene polymer (C) is less than 10. It is excellent in the tear strength of MD direction of the film obtained at the time of T-die film formation at high speed in this range, and it is preferable. The molecular weight distribution is preferably 4-8. In addition, molecular weight distribution as used in this invention is evaluated by ratio (Mw / Mn) of a weight average molecular weight (Mw) and a number average molecular weight (Mn).
[0021]
Further, from the viewpoint of the melt strength of the propylene polymer (C), the intrinsic viscosity [η] of the (a)_a (Dl / g) and content W_a More preferably, (% by weight) satisfies the following formula 2.
W_a ≧ 400 × EXP (−0.6 × [η]_a [Formula 2]
W_a Is within the range of the above formula, it is preferable that the die swell ratio in the composition is easily in a suitable range.
[0022]
The (a) and (b) are each a crystalline propylene polymer portion having an isotactic polypropylene crystal structure, and a propylene homopolymer or an amount of ethylene and / or propylene so as not to lose crystallinity. Alternatively, a copolymer with a comonomer such as an α-olefin having 4 to 12 carbon atoms is preferable. Examples of the α-olefin include 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene and the like. For example, in the case of ethylene, the content of repeating units derived from ethylene in the copolymer is usually 10% by weight or less, such as 1-butene. In the case of the α-olefin, the content of the repeating unit derived from the α-olefin in the copolymer is usually 30% by weight or less.
[0023]
In addition to the above, (b) can also be exemplified by a polymer in which an amorphous ethylene / α-olefin copolymer is dispersed in a crystalline propylene polymer resin (A). .
Particularly preferably as (a) and (b), a homopolymer of propylene, a random copolymer of propylene and ethylene each having a content of repeating units derived from ethylene of 10% by weight or less, carbon It is derived from a random copolymer of propylene having a repeating unit derived from an α-olefin having 4 to 12 atoms and 30% by weight or less and an α-olefin having 4 to 12 carbon atoms, or ethylene. Propylene and ethylene having a repeating unit content of not more than 10% by weight and a repeating unit content of not more than 30% by weight derived from an α-olefin having 4 to 12 carbon atoms and α- having 4 to 12 carbon atoms It is a ternary random copolymer with olefin. In these cases, 1-butene is most preferable as the α-olefin.
As the (a) showing particularly excellent performance with respect to flexibility and impact resistance, a random copolymer of propylene and ethylene in which the amount of repeating units derived from ethylene is 1 to 10% by weight is used.
[0024]
The (a) and (b) may be the same composition or different. Further, (a) and (b) may be combined in a block manner. Further, a combination of (a) and (b) in a block form and the other (a) and (b) may coexist.
[0025]
The propylene polymer (C) is produced using various known catalysts, and as such a catalyst, a multisite catalyst obtained using a solid catalyst component containing a titanium atom, a magnesium atom and a halogen atom, Or the single site catalyst etc. which are obtained using a metallocene complex etc. are mentioned. The propylene polymer (C) is preferably produced by using a multi-site catalyst obtained by using a solid catalyst component containing a titanium atom, a magnesium atom and a halogen atom, and more preferably, JP-A-11-228629. Manufactured by the described method.
[0026]
In order to further improve the physical properties of the polypropylene resin composition of the present invention, 2,6-di-t-butyl-p-cresol (BHT), tetrakis [methylene-3- (3 , 5-di-t-butyl-4-hydroxyphenyl) propionate] methane (IRGANOX 1010) and n-octadecyl-3- (4′-hydroxy-3,5′-di-t-butylphenyl) propionate (IRGANOX 1076) ) And phenolic stabilizers typified by bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite and tris (2,4-di-t-butylphenyl) phosphite System stabilizers, lubricants represented by higher fatty acid amides and higher fatty acid esters, fatty acid greases having 8 to 22 carbon atoms Antistatic agent such as serine ester, sorbitan acid ester and polyethylene glycol ester, anti-blocking agent represented by silica, calcium carbonate, talc, etc., ethylene-α-olefin copolymer, low density polyethylene, high density polyethylene, etc. A polyethylene resin or the like may be added.
[0027]
Processability improvers, stabilizers, lubricants, anti-blocking agents, etc. to be blended according to various purposes may be subjected to film processing after melt-kneading with the polypropylene resin composition of the present invention in advance, or individually. Either dry blending or one or more master batches may be used for film processing after dry blending, and any method may be used.
[0028]
The polypropylene-based resin composition of the present invention is a polypropylene-based resin composition for forming a T-die film at a high speed, and is excellent in the balance of transparency, appearance and tear strength in the MD direction of the obtained film, and improved productivity. It is possible to improve film properties. That is, the polypropylene resin composition of the present invention is a polypropylene resin composition for forming a T-die film at a film forming speed of 130 to 1000 m / min, and the film forming speed is more preferably 150 to 700 m / min. More preferably, it is 170-500 m / min, Most preferably, it is 220-400 m / min.
[0029]
The method for producing a T-die film of the present invention is a method for producing a T-die film that is processed using a polypropylene resin composition of the present invention at a film-forming speed of 130 to 1000 m / min. More preferably, it is 150-700 m / min as a speed | rate, More preferably, it is 170-500 m / min, Most preferably, it is 220-400 m / min.
[0030]
The T-die film processing apparatus used in the T-die film manufacturing method of the present invention is not particularly limited, and examples thereof include a known T-die film processing apparatus and a known extrusion laminating apparatus, preferably a T-die film. It is a processing device.
As preferable film forming conditions in the manufacturing method of the T-die film of the present invention, conditions of a resin temperature of 190 to 300 ° C. and a cooling roll temperature of 20 to 50 ° C. can be applied.
[0031]
The T-die film obtained in the present invention is a T-die film made of the above polypropylene resin composition, and may be a single layer film or a multilayer film including at least one layer made of the polypropylene resin composition. Good.
Although the use which uses this film is not specifically limited, For example, it can be used for food packaging uses, such as bread and vegetables, clothing packaging uses, such as a shirt, and industrial parts packaging use. The film is made of a cellophane, paper, woven fabric, paperboard, aluminum foil, polyamide resin such as nylon 6 or nylon 66, polyester such as polyethylene terephthalate or polybutylene terephthalate by a known technique such as a lamination method such as dry lamination or sand lamination. It can also be used as a film laminated on a substrate such as resin or stretched polypropylene.
[0032]
【Example】
EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited at all by these examples.
The evaluation method is as follows.
[0033]
(1) Intrinsic viscosity of polymer (unit: dl / g)
The measurement was performed in 135 ° C. tetralin using an Ubbelohde viscometer. In addition, the intrinsic viscosity of the crystalline propylene polymer portion (b) in Reference Example 1 below is determined from the crystalline propylene polymer portion (a) and the intrinsic viscosity of the entire polymer, using the calculation formula described in the specification. It was.
[0034]
(2) Melt flow rate (MFR)
It measured at 230 degreeC according to the method of the condition 14 (Condition Number 14) of JISK7210. (Unit: g / 10 minutes)
[0035]
(3) Die swell ratio (SR)
The diameter of the cross section of the extrudate at the time of melt flow rate (MFR) measurement according to the method of condition 14 of JIS K7210 was measured and determined from the following equation.
Die swell ratio = Extrudate cross section diameter / Orifice diameter
However, the cross section of the extrudate means a cross section perpendicular to the extruding direction of the extrudate, and when the cross section is not a true circle, the average value of the maximum and minimum values of the diameter of the cross section is calculated as the cross section of the extrudate. The diameter.
[0036]
(4) Molecular weight and molecular weight distribution
G. P. C. (Gel permeation chromatography) was measured under the following conditions. The molecular weight distribution was evaluated by the ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn).
Model: 150CV type (Millipore Waters);
Column: Shodex M / S 80;
Measurement temperature: 145 ° C;
Solvent: orthodichlorobenzene;
Sample concentration: 5 mg / 8 mL;
A calibration curve was prepared using standard polystyrene.
[0037]
(5) Haze (transparency)
It measured according to JIS K7105.
[0038]
(6) Elmendorf tear strength (unit: kN / m)
The film was measured in the MD direction according to JIS Z1702.
[0039]
(7) Film appearance
Visual evaluation was performed about the presence or absence of the touch roll trace on the obtained film surface. The evaluation was carried out with a case where the touch roll mark was attached as x and a case where the touch roll mark was not attached as ◯.
[0040]
  The polymers used in Examples and Comparative Examples are as follows.
PP-1: manufactured by Sumitomo Chemical Co., Ltd., propylene homopolymer resin, trade name Noblene Y101, lot number FAZ356, MFR = 10, SR = 1.69, molecular weight distribution (Mw / Mn) = 6.8;
PP-2: manufactured by Sumitomo Chemical Co., Ltd., propylene homopolymer resin, trade name Noblene Y101, lot number FAH468, MFR = 13, SR = 1.25, molecular weight distribution (Mw / Mn) = 3.9;
PP-3: propylene homopolymer obtained in Reference Example 1 below, MFR = 12, SR = 2.35, molecular weight distribution (Mw / Mn) = 8.0, weight average molecular weight (Mw) = 3.4 × 10^Five;
[0041]
[Reference Example 1] (PP-3: Production of propylene homopolymer)
[1] (Synthesis of solid catalyst component)
After replacing a 200 liter SUS reaction vessel equipped with a stirrer with nitrogen, 80 liters of hexane, 6.55 moles of tetrabutoxytitanium, 2.8 moles of diisobutyl phthalate, and 98.9 moles of tetraethoxysilane were added to obtain a uniform solution. did. Next, 51 liters of a diisobutyl ether solution of butyl magnesium chloride having a concentration of 2.1 mol / liter was gradually added dropwise over 5 hours while maintaining the temperature in the reaction vessel at 5 ° C. After completion of the dropwise addition, the mixture was further stirred at room temperature for 1 hour, then solid-liquid separation was performed at room temperature, and washing with 70 liters of toluene was repeated three times.
Next, after adding toluene so that the slurry concentration becomes 0.6 kg / liter, a mixed solution of 8.9 mol of n-butyl ether and 274 mol of titanium tetrachloride is added, and 20.8 mol of phthalic acid chloride is further added. The mixture was stirred at 110 ° C. for 3 hours. Thereafter, solid-liquid separation was performed, and washing with 90 liters of toluene was performed twice at 95 ° C.
Next, after adjusting the slurry concentration to 0.6 kg / liter, 3.13 mol of diisobutyl phthalate, 8.9 mol of n-butyl ether and 137 mol of titanium tetrachloride were added, and the mixture was stirred at 105 ° C. for 1 hour. Then, after solid-liquid separation at the same temperature, washing with 90 liters of toluene was performed twice at 95 ° C.
Next, after adjusting the slurry concentration to 0.6 kg / liter, 8.9 mol of n-butyl ether and 137 mol of titanium tetrachloride were added, and the mixture was stirred at 95 ° C. for 1 hour. Thereafter, solid-liquid separation was performed at the same temperature, and washing with 90 liters of toluene was performed three times at the same temperature.
Next, after adjusting the slurry concentration to 0.6 kg / liter, 8.9 mol of n-butyl ether and 137 mol of titanium tetrachloride were added, and the mixture was stirred at 95 ° C. for 1 hour. Thereafter, the solid and liquid were separated at the same temperature and washed with 90 liters of toluene three times at the same temperature, and further washed with 90 liters of hexane three times and then dried under reduced pressure to obtain 11.0 kg of a solid catalyst component. .
The solid catalyst component contains 1.9% by weight of titanium atom, 20% by weight of magnesium atom, 8.6% by weight of phthalate ester, 0.05% by weight of ethoxy group, and 0.21% by weight of butoxy group. It had a good particle property.
[0042]
[2] (Preactivation of solid catalyst component)
Made of SUS with an internal volume of 3 liters, fully dehydrated and degassed in an autoclave with a stirrer 1.5 liters of n-hexane, 37.5 mmol of triethylaluminum, 3.75 mmol of t-butyl-n-propyldimethoxysilane, the above 15 g of the solid catalyst component obtained in [1] was added, and 15 g of propylene was continuously supplied over 30 minutes while maintaining the temperature in the tank at 5 to 15 ° C., and preactivation was performed.
[0043]
[3] (Polymerization of crystalline propylene polymer part (a))
In a polymerization tank made of SUS with an internal volume of 300 liters, a polymerization temperature of 60 ° C. and a polymerization pressure of 27 kg / cm² While supplying liquid propylene at 57 kg / h so as to maintain G, triethylaluminum 1.3 mmol / h, t-butyl-n-propyldimethoxysilane 0.13 mmol / h and the same as [2] above. A preactivated solid catalyst component of 0.51 g / h was continuously fed, and propylene polymerization was carried out in the substantial absence of hydrogen to obtain a 2.0 kg / h polymer. The amount of the polymer produced at this time was 3920 g per gram of the solid catalyst component, and as a result of sampling and analyzing a part thereof, the intrinsic viscosity was 7.7 dl / g. The obtained polymer was continuously transferred to the second tank as it was.
[0044]
[4] (Polymerization of crystalline propylene polymer part (b))
Internal volume 1m^Three In a fluidized bed reactor with a stirrer (second tank) at a polymerization temperature of 80 ° C. and a polymerization pressure of 18 kg / cm.² G, catalyst-containing polymer and triethylaluminum 60 mmol / h, t-butyl-n-propyl transferred from the first tank while supplying propylene and hydrogen so as to maintain a hydrogen concentration of 8 vol% in the gas phase Propylene polymerization was continuously continued while feeding 6 mmol / h of dimethoxysilane to obtain 18.2 kg / h of polymer. The intrinsic viscosity of this polymer was 1.9 dl / g.
From the above results, the polymer production amount during the polymerization of (b) is 31760 g per gram of the solid catalyst component, the polymerization weight ratio of the first tank and the second tank is 11:89, and the limit of (b) The viscosity was determined to be 1.2 dl / g.
[0045]
[5] (Polymerization of polymer)
With respect to 100 parts by weight of this polymer powder, 0.1 part by weight of calcium stearate, 0.05 part by weight of trade name Irganox 1010 (manufactured by Ciba Geigy), 0.2 part by weight of trade name Sumilizer BHT (manufactured by Sumitomo Chemical Co., Ltd.) Part is added and melt-kneaded at 230 ° C., and the weight average molecular weight (Mw) is 3.4 × 10.^Five A propylene homopolymer pellet having a molecular weight distribution (Mw / Mn) of 8.0, an MFR of 12 g / 10 min, and a die swell ratio (SR) of 2.35 was obtained.
[0046]
[Example 1]
A composition obtained by pellet-blending 11 parts by weight of PP-3 with respect to 100 parts by weight of PP-2 was melt-kneaded with two 65 mmφ extruders and 90 mmφ extruders at a resin temperature of 230 to 260 ° C. It was introduced into a feed block type T die (die width 1250 mm, lip opening 0.8 mm) heated to 0 ° C. and melt extruded. The melt-extruded film was cooled and solidified with a cooling roll that was adjusted to 40 ° C. and rotated at 300 m / min to obtain a single-layer unstretched film having a thickness of 20 μm. The evaluation results are summarized in Table 1.
[0047]
[Comparative Example 1]
PP-1 was melt-kneaded with two 65 mmφ extruders and 90 mmφ extruders at a resin temperature of 230 to 260 ° C., and the temperature was raised to 225 ° C. Feed block type T die (die width 1250 mm, lip opening) 0.8 mm) and melt extrusion was performed. The melt-extruded film was cooled and solidified with a cooling roll that was adjusted to 40 ° C. and rotated at 300 m / min to obtain a single-layer unstretched film having a thickness of 20 μm. The evaluation results are summarized in Table 1.
[0048]
[Comparative Example 2]
PP-2 was melt-kneaded with two 65 mmφ and 90 mmφ extruders at a resin temperature of 230 to 260 ° C., and the temperature was raised to 225 ° C. Feed block type T die (die width 1250 mm, lip opening) 0.8 mm) and melt extrusion was performed. The melt-extruded film was cooled and solidified with a cooling roll that was adjusted to 40 ° C. and rotated at 300 m / min to obtain a single-layer unstretched film having a thickness of 20 μm. The evaluation results are summarized in Table 1.
[0049]
[Table 1]

[0050]
【The invention's effect】
As described above in detail, according to the present invention, a polypropylene-based resin from which a film excellent in the balance of transparency, appearance and tear strength in the MD direction can be obtained even when a T-die film is formed at high speed, and A film comprising the same and a method for producing a T-die film excellent in the balance of transparency, appearance, and tear strength in the MD direction even when a T-die film is formed at a high speed are provided.

Claims (1)

100 parts by weight of a propylene polymer resin (A) having a die swell ratio of 1.00 to 1.60 and 0.01 to 45 of a propylene polymer resin (B) having a die swell ratio of 1.80 to 3.00 A process for producing a T-die film, characterized in that a T-die film is processed at a film forming speed of 130 to 300 m / min using a polypropylene resin composition containing parts by weight.