JP2844290B2 - Method for producing polypropylene and molded article - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to polypropylene having a high melt tension. More specifically, a method for producing a polypropylene having a high melt tension, which has a high melt tension and a high crystallization temperature, is excellent in rigidity and moldability, and which can be used again as a molded article, then re-melted and recycled. Related to molded products.

[0002]

2. Description of the Related Art Crystalline polypropylene has mechanical properties,
It is widely used in various molding fields because it has excellent chemical resistance and is very useful in balance with economic efficiency. However, since the melt tension is low and the crystallization temperature is low, moldability such as hollow molding, foam molding, and extrusion molding is poor.

As a method for increasing the melt tension and crystallization temperature of crystalline polypropylene, a method of reacting an organic peroxide and a crosslinking assistant with crystalline polypropylene in a molten state (JP-A-59-93711, JP-A-61-
No. 152754), however, there is a problem that the modified polypropylene obtained by using the crosslinking aid has an odor remaining. In addition, the melt tension is not sufficiently improved, and if the amount of the organic peroxide and the crosslinking aid is increased to increase the melt tension, a gel will be generated. It was impossible to do that.

On the other hand, Japanese Patent Application Laid-Open No. 2-298536 discloses that a polypropylene having a free-end long-chain branch and containing no gel is prepared by reacting a semi-crystalline polypropylene with a peroxide having a low decomposition temperature in the absence of oxygen. Although a method for obtaining the polypropylene has been disclosed, improvement in the melt tension of the obtained polypropylene has been insufficient.

[0005]

As described above, the polypropylene obtained by the method of the prior application has insufficient melting tension and crystallization temperature, has an odor, and contains a gel. After using it as a molded product,
There was a problem that it was impossible to re-melt and use it for recycling.

[0006] The present inventors have solved the problems of the above-mentioned known inventions and have intensively studied a polypropylene suitable for hollow molding, foam molding, extrusion molding and the like, and a method for producing the same. As a result, a specific organic peroxide is reacted with polypropylene under specific conditions, and further melt-kneaded to obtain a polypropylene having a specific structure and properties. It has been found that the problem can be solved, and the technical content thereof has already been disclosed in Japanese Patent Application No. 4-339873. As a result of further research, the present inventors have found that when a polypropylene composition containing a specific amount of high-viscosity polypropylene is used as the polypropylene used in the reaction, the melt tension is further remarkably improved. The present invention has been made based on the above.

As is apparent from the above description, it is an object of the present invention to provide a material having extremely high melt tension and crystallization temperature, excellent rigidity and moldability, and after being used as a molded article, remelted and recycled. process for producing a polypropylene and its is also possible, to provide a further molded article formed using the polypropylene.

[0008]

The present invention provides the following (1).
And (2). (1) Under an inert gas atmosphere, a linear crystalline polypropylene (PP1) is reacted with di-2-ethylhexyl peroxydicarbonate, and then melt-kneaded, whereby the branching index is substantially 1 And (A) the melt tension (MS) at 230 ° C. and the intrinsic viscosity [η] measured in tetralin at 135 ° C. are: log (MS)> 4.24 × log [η] −0.685, and (B) a differential scanning calorimeter (DS)
Crystallization temperature (Tc) and melting point (Tm) measured by C)
Satisfies the relationship of (Tc)> 0.784 × (Tm) −4.00, and (C) a method of producing polypropylene (PP2) having a boiling xylene extraction residual ratio of 1% by weight or less. Te, linear crystalline polypropylene (P
As P1), an intrinsic viscosity [η] of 1 to 50% by weight of a crystalline polypropylene (PP3) having an intrinsic viscosity [η] of 2.5 to 10 dl / g measured in tetralin at 135 ° C. Is 1.0 to 4.0 dl
/ G, using a crystalline polypropylene composition (PP4).

(2) A crystalline polypropylene (P) having an intrinsic viscosity [η] of 2.5 to 10 dl / g measured in tetralin at 135 ° C. in an inert gas atmosphere.
A crystalline polypropylene composition (PP4) containing 1 to 50% by weight of P3) and having an intrinsic viscosity [η] of 1.0 to 4.0 dl / g as di-2-ethylhexyl peroxydicarbonate Is a linear crystalline polypropylene having a branching index of substantially 1, obtained by a method of melt-kneading after the reaction, and (A)
Melt tension (MS) at 230 ° C and 1 in tetralin
The intrinsic viscosity [η] measured at 35 ° C. is expressed as log (MS)> 4.24 × log [η] −0.685, and (B) a differential scanning calorimeter (DS)
Crystallization temperature (Tc) and melting point (Tm) measured by C)
Satisfies the relationship of (Tc)> 0.784 × (Tm) −4.00, and (C) polypropylene having a boiling xylene extraction residual ratio of 1% by weight or less .

The configuration of the present invention will be described below in detail. The polypropylene of the present invention contains not only propylene homopolymer but also 10 units of olefin polymer units other than propylene.
It also includes a propylene-olefin random copolymer containing less than about 10% by weight, and the description of polypropylene is used in this sense hereinafter.

The polypropylene (PP2) obtained by the method of the present invention is a linear crystalline polypropylene having a branching index of substantially 1, and the branching index indicates the degree of long-chain branching. Is defined by the following equation. Branching degree index (g) = [η] Br / [η] Lin Here, [η] Br is the intrinsic viscosity of the branched polypropylene, and in this specification, is the measured value [η] Obs of the polypropylene of the present invention. Also, [η] Lin in the present specification,
In the method for producing the polypropylene of the present invention described below, the above [η] obtained by the same method as the linear crystalline polypropylene obtained by a known method used as a raw material
This is the intrinsic viscosity of a linear crystalline polypropylene having the same weight average molecular weight as the Obs sample. The above ratio of the intrinsic viscosity indicates the degree of branching of the non-linear polymer, and is less than 1 when a long-chain branch is present.

The intrinsic viscosity was measured at 135 ° C. on a sample dissolved in tetralin. Also,
Weight average molecular weight (Mw) and number average molecular weight (Mn)
By American Laboratory, Ma by MLMcConnell
y, 63-75 (1978), ie, low angle laser light scattering photometry.

The polypropylene (PP) obtained by the present invention
2) has a branching degree index of substantially 1 according to the above definition and measuring method, and does not have a long-chain branched structure. In addition, being substantially 1 means that even if there is a long-chain branch, it is below the detection limit by the above method, and the range of statistical error when the same sample is repeatedly measured by the above method. It includes the meaning of 1 including. Therefore, a practical value is about 0.95 to 1.05.
Since the degree of branching index is substantially 1, except for the characteristic properties of the polypropylene of the present invention described below, it has the same properties as the conventionally known linear polypropylene, so that the conventionally known linear It has a feature that the molding method and apparatus used for polypropylene can be used as they are.

Further, the polypropylene (PP2) obtained by the present invention has the following three essential requirements. That is, (A) the melt tension (MS) at 230 ° C. and the intrinsic viscosity [η] measured in tetralin at 135 ° C. are represented by log (MS)> 4.24 × log [η] −0.685. And (B) Differential scanning calorimeter (DS)
Crystallization temperature (Tc) and melting point (Tm) measured by C)
And (Tc)> 0.784 × (Tm) −4.00, and (C) the boiling xylene extraction residual ratio further satisfies 1% by weight or less.

As described above, the melt tension of polypropylene required to achieve the object of the present invention is, as described above, the melt tension (MS) at 230 ° C. and the intrinsic viscosity [η] measured at 135 ° C. in tetralin. log (MS)> 4.24
log [η] −0.685, more preferably log (MS)> 4.24 log [η] −0.47
It is necessary that the relationship shown by 0 be satisfied.

Here, the melt tension at 230 ° C. (M
S) uses a melt tension tester type 2 manufactured by Toyo Seiki Seisaku-Sho, Ltd. to convert polypropylene into 230
℃, melted polypropylene 2.095mm in diameter
From the nozzle at a speed of 20 mm / min into the air at 23 ° C. to form a strand.
The tension of the filamentous polypropylene at the time of drawing at a rate of / minute was measured and defined as a melt tension (MS).

The crystallization temperature of polypropylene required to achieve the object of the present invention is, as described above, a crystallization temperature (Tc) and a melting point (Tm) measured by a differential scanning calorimeter (DSC). Is (Tc)> 0.784 ×
The relationship represented by (Tm) −4.00, more preferably the relationship represented by (Tc)> 0.784 × (Tm) −3.00, must be satisfied. If this relationship is not satisfied, the crystallization is slow and the good moldability characteristics of the polypropylene obtained in the present invention are lost.

The crystallization temperature (Tc) and the melting point (Tm) of the polypropylene were raised from room temperature to 230 ° C. from room temperature by 30 ° C./min using a DSC7 differential scanning calorimeter manufactured by Perkin Elmer. After holding at the same temperature for 10 minutes,
The temperature was lowered to -20 ° C at -20 ° C / min, and
After holding for 20 minutes, the temperature showing the maximum peak at the time of melting under a heating condition of 20 ° C./min was defined as a melting point (Tm). Further, after the melting point peak appeared, the temperature was continuously raised to 230 ° C. under the same conditions, and the temperature was maintained at the same temperature for 10 minutes.
The temperature was lowered to 50 ° C., and from 150 ° C., the temperature at which the maximum peak was reached during crystallization while the temperature was lowered at −5 ° C./min was defined as the crystallization temperature (Tc).

The polypropylene obtained by the present invention must have a boiling xylene extraction residual ratio of 1% by weight or less, more preferably 0.6% by weight or less, as described above. If the extraction residual ratio is large, the moldability deteriorates, and it becomes extremely difficult to re-melt and recycle after use as a molded article.

The boiling xylene extraction residual ratio was determined by placing 1 g of polypropylene in a 200-mesh wire net using a Soxhlet extractor, extracting with 200 ml of p-xylene with boiling xylene for 6 hours, and drying and weighing the extracted residue. It was calculated as (weight of extraction residue / weight before extraction) × 100%.

Next, a detailed method for producing the above-mentioned polypropylene (PP2) obtained by the present invention will be described.
As the crystalline polypropylene (PP1) used in the method for producing polypropylene according to the present invention, crystalline polypropylene having an intrinsic viscosity [η] of 2.5 to 10 dl / g measured at 135 ° C. in tetralin from the viewpoint of improving the melt tension. It is necessary to use a crystalline polypropylene composition (PP4) containing 1 to 50% by weight of (PP3) and having an overall intrinsic viscosity [η] of 1.0 to 4.0 dl / g. If the intrinsic viscosity of the crystalline polypropylene (PP3) is less than 2.5 dl / g, the effect of improving the melt tension is low, and if it is more than 10 dl / g, a gel is generated in the obtained polypropylene, which is outside the scope of the present invention. The ratio of the high-viscosity crystalline polypropylene (PP3) to the entire crystalline polypropylene composition (PP4) obtained by mixing one or more types of crystalline polypropylene (PP5) with the high-viscosity crystalline polypropylene (PP3) is 1 If the content is less than 50% by weight, the effect of improving the melt tension is low, and if it exceeds 50% by weight, a gel is generated in the obtained polypropylene or the processability deteriorates. Further, the intrinsic viscosity of the crystalline polypropylene composition (PP4) as a whole is 1.0 dl /
If it is smaller than g, the impact strength of the obtained polypropylene is low, and if it is larger than 4.0 dl / g, the obtained polypropylene becomes poor in processability.

The stereoregularity of the crystalline polypropylene (PP1) used in the method for producing polypropylene of the present invention is not particularly limited. However, in order for the obtained polypropylene (PP2) to have high rigidity, a certain degree or more is required. It is desirable to have stereoregularity. That is, when a propylene homopolymer is used as the crystalline polypropylene (PP1), the stereoregularity (II) represented by an extraction residual ratio (% by weight) after extraction in boiling n-heptane for 6 hours.
80% or more, preferably 90% or more, particularly preferably 95% or more of crystalline polypropylene. When a propylene-olefin random copolymer is used, the stereoregularity (II) is 20% or more, preferably 30%.
% Or more of crystalline polypropylene is used. The polypropylene (PP2) obtained by the production method of the present invention is a crystalline polypropylene composition (PP) used as a raw material.
If a polypropylene (PP2) having higher rigidity than that of 4) but particularly high rigidity is desired, the stereoregularity defined above can be adjusted to a crystalline polypropylene composition (PP2).
4) It is preferable to fall within the above range as a whole.

The method for producing the polypropylene composition (PP4) containing the crystalline polypropylene (PP3) having a specific intrinsic viscosity used in the above-mentioned method of the present invention is not particularly limited, and various known methods can be used. . For example, a known method, that is, a titanium catalyst component (a solid composition containing titanium trichloride as a component, or a solid composition in which titanium tetrachloride is supported on a carrier such as a magnesium compound such as magnesium chloride, silica, or a polymer) is used. An electron donor component having a combination of an organoaluminum compound and, in some cases, any of oxygen, nitrogen, phosphorus, and sulfur atoms, such as ethers, esters, and an organosilicon compound having a Si—O—C bond Using a so-called Ziegler-Natta catalyst in which propylene is polymerized in an inert solvent, bulk polymerization using propylene itself as a solvent, and propylene gas as the main component, further using a so-called Ziegler-Natta catalyst There is a gas phase polymerization performed in the gas phase. Further, crystalline polypropylene (PP3) having an intrinsic viscosity [η] of 2.5 to 10 dl / g, which is obtained by a known method in which these are combined, is separately manufactured in the same manner as at least one kind of different intrinsic viscosity. a method of mixing a crystalline polypropylene (PP5), intrinsic viscosity at any one step in how to manufacture by polymerizing a different crystalline polypropylene having an intrinsic viscosity in multiple stages [eta] is 2.5~10d
A method is possible by including a step of polymerizing 1 / g of crystalline polypropylene (PP3).

Further, the crystalline polypropylene (PP3) having an intrinsic viscosity [η] of 2.5 to 10 dl / g constituting the crystalline polypropylene composition (PP4) used in the method for producing polypropylene of the present invention and having a different intrinsic viscosity. The one or more crystalline polypropylenes (PP5) include not only propylene homopolymers but also olefins other than propylene, for example, ethylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1 and the like. Linear monoolefins, branched monoolefins such as 4-methylpentene-1 and 2-methylpentene-1, and random copolymers of styrene and propylene with propylene can also be used. When a copolymer is used, the olefin other than propylene is not limited to one type, and two or more olefins may be included. Specifically, a propylene-ethylene copolymer,
Propylene-butene-1 copolymer, propylene-hexene-1 copolymer, propylene-octene-1 copolymer,
Examples thereof include propylene-4-methylpentene-1 copolymer, propylene-ethylene-butene-1 copolymer, and propylene-ethylene-4-methylpentene-1 copolymer. At this time, it is necessary that the content of olefin polymer units other than propylene in the copolymer is 10% by weight or less. 1
If it exceeds 0% by weight, a gel is easily generated in the obtained polypropylene, which is outside the scope of the present invention.

The form of the crystalline polypropylene composition (PP4) used in the present invention is not particularly limited, and may be in the form of powder, pellet, film, sheet or the like. For this reason, a powder in a state immediately after the completion of the polymerization step obtained by the above-described various methods and before pelletization, or a mixture of the powders is a preferable embodiment. The average particle size of the powder is about 50 μm to 5 mm. In terms of reaction efficiency, it is preferable that the particle size is small,
Since the larger the particle size is preferable from the viewpoint of powder fluidity,
It is preferable to use one having a particle size appropriate for the purpose.

In the present invention, di-2-ethylhexyl peroxydicarbonate reacted with the crystalline polypropylene composition (PP4) has a decomposition temperature of 92 ° C. when the half-life is 1 minute, and a half-life of 1 hour. Decomposition temperature at 60
It is an organic peroxide showing ° C. The use of similar percarbonates having similar decomposition temperatures does not achieve the objects of the present invention, as will be apparent from the examples below.

At the time of addition and mixing with the crystalline polypropylene composition (PP4), toluene, xylene, isoparaffin, octane,
It is convenient to use those diluted in an inert solvent represented by a hydrocarbon solvent such as decane. The concentration of di-2-ethylhexyl peroxydicarbonate in the solvent is 10 to 9
About 0% by weight is used.

The reaction between the crystalline polypropylene composition (PP4) and di-2-ethylhexyl peroxydicarbonate in the method of the present invention is carried out in a reaction vessel under an inert gas atmosphere such as nitrogen or argon. Di-2-ethylhexyl peroxydicarbonate is added to the composition (PP4) and mixed. The temperature at this time is desirably 40 ° C. or less and 0 ° C. or more. In addition, it is desirable to stir so as to sufficiently mix. The amount of addition is 1 to 100 g of the crystalline polypropylene composition (PP4).
10 mmol is desirable, and especially 2 to 10 mmol is desirable. If the amount used is small, the effect of the modification is insufficient, and if it is too large, not only the effect cannot be expected to be improved, but also an odor remains or the polypropylene becomes unstable with a long term deterioration.

The mixed crystalline polypropylene composition (PP4) and di-2-ethylhexyl peroxydicarbonate are subsequently mixed in an inert gas atmosphere in a reaction vessel, if necessary, under stirring conditions. 150
The reaction is carried out at a temperature of 75 ° C., preferably 75 to 140 ° C. for 5 minutes to 5 hours, preferably 10 minutes to 3 hours.

After the reaction, the reaction product is taken out of the reaction vessel and further melt-kneaded to obtain the polypropylene (PP2) which is the object of the present invention.
Is obtained. For the melt kneading, a known melt kneading method is used. For example, using a single-screw extruder, a twin-screw extruder, an extruder combining these and a gear pump, a Brabender, a Banbury mixer, or the like, at a temperature equal to or higher than the melting point of polypropylene for about 10 seconds to 1 hour, preferably 20 seconds to 30 hours. Melt and knead for about a minute. By melt-kneading, the crystallization temperature is significantly increased, and the characteristics of polypropylene (PP2) according to the method of the present invention appear. The crystallization temperature in the powder before the melt-kneading is the same as that before the reaction or only slightly increased.

After the melt-kneading, it is usually cut into granules to form pellets, which are used for various molded products. However, they can be processed immediately after the melt-kneading to obtain molded products. In addition,
After washing with an inert solvent if necessary in a powder state before melt-kneading, it is also possible to dry and then melt-knead.

When melt-kneading, an antioxidant, an ultraviolet absorber, an antistatic agent, a nucleating agent, a lubricant, a flame retardant, an antiblocking agent, a coloring agent,
Various additives such as inorganic or organic fillers can be blended.

The polypropylene (PP2) of the present invention can be obtained by the above-mentioned method. However, after the completion of the reaction and before the melt-kneading, the reaction product is continuously obtained under an inert gas atmosphere and, if necessary, under stirring conditions. Post-heating at 100 to 150 ° C. is a desirable embodiment of the present invention.
Processing time is 10 minutes to 2 hours, preferably 15 minutes to 1 hour.
Time is appropriate. By the post-heating treatment, the reaction efficiency is increased, the odor of the obtained polypropylene is further reduced, and a stabilized polypropylene with little change over time is obtained.

The polypropylene (PP2) which is the object of the present invention is obtained by the above-mentioned method, and the polypropylene must have the above-mentioned characteristics. Unless these characteristics are satisfied, the object of the present invention cannot be achieved.

The polypropylene (PP2) obtained by the method of the present invention thus obtained has an extremely high melt tension and crystallization temperature, is excellent in rigidity and moldability, and is remelted after being used as a molded article. Since it can be recycled, it is particularly suitable for hollow molding, foam molding, and extrusion molding.
-Various containers such as hollow containers by die forming, thermoforming, etc.
It can be used for various molded products such as films, sheets, pipes and fibers.

[0036]

The reaction mechanism for obtaining polypropylene in the process of the present invention is not known at present,
It is thought that radicals generated from 2-ethylhexyl peroxydicarbonate have caused some interaction with polypropylene. In particular, since the change in the polypropylene portion having a high intrinsic viscosity [η] of 2.5 to 10 dl / g has a greater effect on the entire polypropylene than the change in the other polypropylene portions having a low intrinsic viscosity, the overall It is presumed to exhibit the melting behavior and the crystallization behavior characteristic of the polypropylene according to the method of the present invention, which are not found in the polypropylene known as "."

[0037]

Next, the present invention will be described specifically with reference to examples. Definitions of terms used in Examples and Comparative Examples and measurement methods are as follows. (1) Intrinsic viscosity: [η], measured by the method described above.
(Unit: dl / g) (2) Weight average molecular weight: (Mw), measured by the method described above. (3) Branching degree index: (g), measured by the method described above. (4) Melt tension: (MS) was measured by the method described above. (Unit: gf) (5) Melting point: (Tm) was measured by the method described above.
(Unit: ° C.) (6) Crystallization temperature: (Tc), measured by the method described above. (Unit: ° C) (7) Rigidity: A JIS-type test piece is prepared from a polypropylene pellet at a molten resin temperature of 230 ° C and a mold temperature of 50 ° C using an injection molding machine, and the humidity of the test piece is set to 50%.
%, At room temperature of 23 ° C. for 72 hours.
The flexural modulus was measured according to 7230. (Unit: k
gf / cm ² )

Example 1 Using a catalyst obtained by combining a titanium trichloride composition obtained by the method described in Example 1 in JP-B-59-28573, diethylaluminum chloride, and diethylene glycol dimethyl ether as a third component,
Using three continuous slurry polymerization reactors connected in series, while maintaining different hydrogen concentrations in the gas phase in each polymerization reactor, the intrinsic viscosity of the polymer [η Is 1.00 dl / g, and the intrinsic viscosity of the polymer formed in the second-stage polymerization in the second-stage polymerization vessel is 50% by weight based on the total polymerization amount. [Η] is 1.50 dl / g, and the amount of polymerization in the second stage is 30% by weight based on the total amount of polymerization.
The intrinsic viscosity [η] of the polymer formed in the second stage polymerization is 3.6.
Propylene is continuously multistage polymerized in n-hexane so that the intrinsic viscosity [η] is 1.68 dl / g, so that the polymerization amount in the third stage is 20% by weight based on the total polymerization amount.
g, stereoregularity (II): 96%, average particle size: 140 μm
m of propylene homopolymer powder was obtained, and was used as it was as a polypropylene composition (PP4) used in the method of the present invention. Subsequently, the polypropylene composition (PP4) 10k
g was placed in a reactor equipped with a stirrer and purged with nitrogen. Then, the operation of evacuating the reactor and supplying nitrogen gas to atmospheric pressure was repeated 10 times, and then di-2-ethylhexyl having a concentration of 70% by weight in toluene solution at 25 ° C. under a nitrogen gas atmosphere with stirring. Peroxydicarbonate 0.3
5 mol was added and mixed. Subsequently, the temperature in the reactor was reduced to 1
The temperature was raised to 20 ° C., and the reaction was performed at the same temperature for 30 minutes. After the elapse of the reaction time, the temperature in the reactor was further increased to 135 ° C.
Post-treatment was performed at the same temperature for 30 minutes. After the post-treatment, the reactor was cooled to room temperature, and then opened to obtain polypropylene. When the melting point (Tm) and the crystallization temperature (Tc) of the polypropylene were measured, each was 161.7 ° C.
117.5 ° C. Subsequently, tetrakis [methylene-] was added to 100 parts by weight of the obtained polypropylene.
3- (3'-5'-di-tert-butyl-4'-hydroxyphenyl) propionate] 0.1 part by weight of methane and 0.1 part by weight of calcium stearate are mixed, and the mixture is extruded with a screw diameter of 40 mm. 2 using a granulator
Granulation was performed at 30 ° C. to obtain polypropylene (PP2) according to the method of the present invention as pellets. Various physical properties of the pellet were measured.

Examples 2 and 3 In Example 1, when obtaining the polypropylene composition (PP4) used in the reaction, propylene was slurry-polymerized in two stages by using two continuous slurry polymerizers connected in series. Using the obtained polypropylene, a polypropylene pellet (PP2) was obtained in the same manner as in Example 1 except that the intrinsic viscosity of the polypropylene and the reaction conditions and post-treatment conditions were changed as shown in the table. .

Comparative Example 1 In Example 1, the polypropylene composition (PP4) used for the reaction was granulated in the same manner as in Example 1 without reacting di-2-ethylhexylperoxydicarbonate with the pellets. Obtained.

Comparative Example 2 In Example 1, when the propylene homopolymer used as a raw material was obtained, the intrinsic viscosity [η] of the polymer formed in the first stage by changing the hydrogen concentration was 1.50 dl / g, The intrinsic viscosity [η] of the polymer formed in the second-stage polymerization is 1.82 dl /
g, and propylene is continuously multi-stage polymerized in n-hexane so that the intrinsic viscosity [η] of the polymer formed in the third stage polymerization becomes 1.92 dl / g. Was 1.68 dl / g to obtain a propylene homopolymer powder. Di-2 was prepared in the same manner as in Example 1 except that 10 kg of the polypropylene was used as a raw material polypropylene.
-After reacting with ethylhexyl peroxydicarbonate, granulation was performed to obtain polypropylene pellets.

Comparative Example 3 In Example 1, when obtaining a propylene homopolymer used as a raw material, propylene was polymerized using one polymerization vessel without multi-step polymerization, and the amount of hydrogen was changed. Propylene was slurry polymerized in the same manner as in Example 1 except that the intrinsic viscosity [η] was 1.68 dl /
g of propylene homopolymer powder was obtained. After reacting with di-2-ethylhexyl peroxydicarbonate in the same manner as in Example 1 except that 10 kg of the polypropylene was used as a raw material polypropylene, the mixture was granulated to obtain polypropylene pellets.

Examples 1 to 3 and Comparative Examples 1 to 3
Table 1 shows the conditions and results.

[0044]

[Table 1]

Example 4 Using a catalyst obtained by combining magnesium chloride-supported titanium catalyst component and triethylaluminum obtained by the method described in Example 1 in JP-A-62-104812, and diisopropyldimethoxysilane as a third component. Therefore, two continuous gas-phase polymerization reactors connected in series are used, and while maintaining different hydrogen concentrations in the gas phase in each polymerization reactor, the polymer inherent in the first-stage polymerization reactor is maintained. The viscosity [η] is 4.10 dl / g, the polymerization amount in the first stage is 30% by weight based on the total polymerization amount, and the weight generated in the second stage polymerization in the second stage polymerization vessel. Propylene is continuously subjected to two-stage gas phase polymerization so that the intrinsic viscosity [η] of the coalesce is 0.76 dl / g and the polymerization amount in the second stage is 70% by weight based on the total polymerization amount. [Η] is 1.76 dl /
g, stereoregularity (II): 98%, average particle size: 780 μm
m of propylene homopolymer powder was obtained. 10 kg of the propylene homopolymer was added to a polypropylene composition (PP
Except for using as 4), a polypropylene pellet (PP2) was obtained in the same manner as in Example 1.

Comparative Example 4 In Example 4, the propylene homopolymer (PP4) used in the reaction was granulated in the same manner as in Example 4 without reacting di-2-ethylhexylperoxydicarbonate with pellets. I got

Comparative Example 5 In the same manner as in Example 4, except that a single polymerization reactor was used and the amount of hydrogen was adjusted, propylene was vapor-phased in the same manner as in Example 4, except that the polypropylene used as a raw material was obtained. By polymerization, a propylene homopolymer powder having an intrinsic viscosity [η] of 1.76 dl / g was obtained. The polypropylene 1
Example 4 except that 0 kg was used as the raw material polypropylene
After reacting with di-2-ethylhexyl peroxydicarbonate in the same manner as described above, the mixture was granulated to obtain polypropylene pellets.

Comparative Example 6 In Example 4, the decomposition temperature when the half-life was 1 minute was 85 ° C. and the decomposition temperature when the half-life was 1 hour in place of di-2-ethylhexylperoxydicarbonate. Is 57
The reaction was carried out in the same manner as in Example 4 except that di-3-methoxybutyl peroxydicarbonate, which was at
Post-processing was performed.

Comparative Example 7 In Example 4, the decomposition temperature when the half-life was 1 minute was 93 ° C. and the decomposition temperature when the half-life was 1 hour in place of di-2-ethylhexylperoxydicarbonate. Is 61
The reaction and post-treatment were carried out in the same manner as in Example 4 except that diisopropyl peroxydicarbonate at a temperature of ° C was used.

Comparative Example 8 In Example 4, the decomposition temperature when the half-life was 1 minute was 112 ° C. and the decomposition temperature when the half-life was 1 hour in place of di-2-ethylhexylperoxydicarbonate. Is 7
The reaction and post-treatment were carried out in the same manner as in Example 4 except that t-butyl peroxypivalate at 3 ° C was used.

Table 2 shows the conditions and results of Example 4 and Comparative Examples 4 to 8 described above.

[0052]

[Table 2]

Example 5 Using the same catalyst as in Example 4, in the first stage, the intrinsic viscosity [η] of the polymer was 3.37 dl / g in the bulk polymerization. Random copolymerization of propylene and ethylene was carried out such that the content of ethylene unit became 35% by weight and the content of ethylene unit became 0.2% by weight. Subsequently, the intrinsic viscosity [η] of the polymer formed in the second-stage polymerization by gas-phase polymerization in the same polymerization vessel is 0.80 dl / g, and the amount of the second-stage polymerization is 65% by weight based on the total amount of polymerization. In addition, random copolymerization of propylene and ethylene was performed so that the ethylene unit content was 0.2% by weight. The intrinsic viscosity [η] thus obtained is 1.70 dl / g, and the ethylene unit content is 0.
A polypropylene pellet was obtained in the same manner as in Example 4 except that 10 kg of a propylene-ethylene random copolymer powder having an average particle diameter of 740 µm was used as a polypropylene composition (PP4) at 2% by weight.

Comparative Example 9 In Example 5, propylene-ethylene random copolymer (PP4) used as a raw material was reacted without reacting di-2-ethylhexyl peroxydicarbonate.
Granulation was performed as in Example 5 to obtain pellets.

Comparative Example 10 In Example 5, when obtaining the polypropylene composition (PP4) used as a raw material, bulk polymerization was carried out in one step without performing polymerization in multiple steps, and the amount of ethylene and the amount of hydrogen were changed. The copolymerization of propylene and ethylene was carried out in the same manner as in Example 5 except that was adjusted. The same procedure as in Example 5 was carried out except that 10 kg of a propylene-ethylene random copolymer powder having an intrinsic viscosity [η] of 1.70 dl / g and an ethylene unit content of 0.2% by weight was used as the starting polypropylene. After reacting with di-2-ethylhexyl peroxydicarbonate, the mixture was granulated to obtain polypropylene pellets.

Example 6 Using the same catalyst as in Example 4, a batch type slurry polymerization reactor was used to copolymerize propylene, ethylene and butene-1 in n-hexane to reduce the ethylene unit content. 3.2% by weight, butene-1 unit content is 2.
A propylene-ethylene-butene-1 random copolymer powder having 5% by weight and an intrinsic viscosity [η] of 3.52 dl / g was obtained. By the same polymerization method, the ethylene unit content was 3.2% by weight, butene-1 unit content was 2.5% by weight,
Thus, two types of propylene-ethylene-butene-1 random copolymer powder having an intrinsic viscosity [η] of 2.21 dl / g and an intrinsic viscosity [η] of 1.50 dl / g were separately obtained. Among the copolymers thus obtained, 0.5 kg of a copolymer having an intrinsic viscosity [η] of 3.52 dl / g, and 1.5 kg of a copolymer having an intrinsic viscosity [η] of 2.21 dl / g
g, and 8 kg of a copolymer having an intrinsic viscosity [η] of 1.50 dl / g were mixed with a polypropylene composition (PP
A polypropylene pellet (PP2) was obtained in the same manner as in Example 4 except that the pellet was used as 4) and the reaction conditions and post-treatment conditions were changed as shown in Table 3.

Comparative Example 11 In Example 6, di-2-ethylhexyl peroxydicarbonate was not reacted with the propylene-ethylene-butene-1 random copolymer mixture (PP4) used as a raw material, and Granulate in the same way as
A pellet was obtained.

Comparative Example 12 By the same polymerization method as in Example 6, the ethylene unit content was 3.2% by weight, butene-1 unit content was 2.5% by weight, and the intrinsic viscosity [η] was 1 .71 dl / g of a propylene-ethylene-butene-1 random copolymer powder was obtained. The copolymer is used as a polypropylene composition (PP
Except for using in place of 4), a polypropylene pellet was obtained in the same manner as in Example 6.

Examples 5 and 6 and Comparative Examples 9 to 12
Table 3 shows the conditions and results.

[0060]

[Table 3]

Example 7 In the same manner as in Example 1, the starting polypropylene composition (PP
4) was reacted with di-2-ethylhexyl peroxydicarbonate, and 100 parts by weight of polypropylene powder was added to tetrakis [methylene-3- (3′-5′-di-
t-butyl-4'-hydroxyphenyl) propionate] methane 0.1 part by weight, calcium stearate 0.1 part by weight.
One part by weight and 0.1 part by weight of talc as a foam nucleating agent were mixed, and the mixture was supplied to a single screw extruder set to a screw diameter of 65 mm and an extruder temperature of 230 ° C. Then, 22 parts by weight of 1,1,2,2-tetrafluorodichloroethane was injected as a foaming agent in the middle of the extruder. Using a nozzle-shaped mold with a diameter of 5 mm attached to the extruder,
Extrusion foam molding was performed at a mold temperature of 155 ° C. The surface of the obtained foam was smooth, and there were no abnormal air bubbles and uniform air bubbles.

Comparative Example 13 In Example 7, a polypropylene composition (PP4) used as a raw material in obtaining the polypropylene powder was used instead of the polypropylene powder obtained by reacting di-2-ethylhexyl peroxydicarbonate. Extrusion foaming was carried out in the same manner except that the foam was used as it was, and the foam obtained was poor in appearance due to outgassing and had large cavities, and was unsatisfactory that could not be used. Was.

Example 8 A propylene-ethylene random copolymer pellet (PP2) obtained in the same manner as in Example 5 was extruded at 260 ° C. using an extruder with a T-die and a screw diameter of 65 mm. Sheeting was performed to obtain a sheet having a thickness of 0.5 mm. Next, in order to modelly evaluate the heat vacuum formability of the sheet, the sheet was fixed to a 40 cm square frame,
It was placed in a constant temperature room at 210 ° C. and the behavior was observed. The center of the sheet began to hang down due to the heating, and when the sheet hanged down by 33 mm, the hang was stopped and, conversely, the hang down was raised. Sixteen seconds after the suspension of the drooping, the sheet began to droop again, and thereafter only drooped. The amount of droop was small and the time until the start of re-droop was as long as 16 seconds, indicating that the sheet was extremely excellent in heat vacuum formability.

Comparative Example 14 In Example 8, the propylene-ethylene random copolymer pellet (PP2) obtained by the method of the present invention was replaced with
A sheet was obtained in the same manner except that pellets of the propylene-ethylene random copolymer obtained in the same manner as in Comparative Example 10 were used. When the heating behavior of the sheet was observed in the same manner as in Example 8, the suspension stopped for 40 m.
m, and the time until the start of re-drooping was as short as 8 seconds, and the heating vacuum formability was inferior to Example 8 above.

Example 9 In order to recycle the molded article of the present invention, many test pieces for measuring the flexural modulus were prepared in the same manner as in Example 1.
A polypropylene composition comprising 10% by weight of a pulverized test piece obtained by subjecting the injection molded test piece to a pulverizer and 90% by weight of a polypropylene pellet obtained in the same manner as in Example 1 was directly blown with a screw diameter of 65 mm. Using a molding machine, at a molding temperature of 230 ° C, a mold temperature of 20 ° C, a kerosene tank with an inner volume of 100 l was hollow-molded.
As for the parison, a uniform hollow molded product without unevenness in thickness was obtained without drawdown.

Comparative Example 15 In Example 9, except that the polypropylene pellets obtained in the same manner as in Comparative Example 2 were used as the polypropylene, hollow molding was performed in the same manner as in Example 8, and the parison was drawn down. This resulted in a non-uniform hollow molded product with uneven thickness.

[0067]

As is clear from the above-described embodiment,
The polypropylene of the present invention has an extremely high melt tension and crystallization temperature, is excellent in rigidity and moldability, and can be used in a wide range of applications limited by conventional polypropylene.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // C08L 23:00

Claims (2)

(57) [Claims] 1. A method in which a linear crystalline polypropylene (PP1) is reacted with di-2-ethylhexyl peroxydicarbonate in an inert gas atmosphere, and then melt-kneaded, whereby a branching index is substantially increased. And (A) the melt tension (MS) at 230 ° C. and the intrinsic viscosity [η] measured in tetralin at 135 ° C. are expressed as log (MS)> (B) The crystallization temperature (Tc) and the melting point (Tm) measured by a differential scanning calorimeter (DSC) are as follows: (Tc) > satisfy the relationship represented by 0.784 × (Tm) -4.00, met method for producing a (C) polypropylene boiling xylene extraction residual rate of 1 wt% or less, (PP2)
As linear crystalline polypropylene (PP1),
An intrinsic viscosity [η] of 1 to 50% by weight of a crystalline polypropylene (PP3) having an intrinsic viscosity [η] of 2.5 to 10 dl / g in tetralin measured at 135 ° C. is 1. A method for producing polypropylene, comprising using a crystalline polypropylene composition (PP4) of 0 to 4.0 dl / g. 2. An intrinsic viscosity [η] measured at 135 ° C. in tetralin in an inert gas atmosphere is 2.
5 to 10 dl / g of crystalline polypropylene (PP
(3) is added to a crystalline polypropylene composition (PP4) having an intrinsic viscosity [η] of 1.0 to 4.0 dl / g as a whole, containing 1 to 50% by weight of di-2-ethylhexyl peroxydicarbonate. Is a linear crystalline polypropylene having a branching index of substantially 1, obtained by a method of melt-kneading after reacting, and (A) a melt tension (MS) at 230 ° C. and tetralin And the intrinsic viscosity [η] measured at 135 ° C. in the following equation: log (MS)> 4.24 × log [η] −0.685; and (B) differential scanning calorimeter (DSC) The crystallization temperature (Tc) and the melting point (Tm) measured by the above satisfy the relationship of (Tc)> 0.784 × (Tm) −4.00, and (C) the boiling xylene extraction residual ratio is 1 wt. % Or less Down.