JPH0867783A - Polypropylene resin composition - Google Patents

Abstract

PURPOSE: To obtain a polypropylene resin compsn. excellent in stiffness, heat resistance, and impact strength. CONSTITUTION: This resin compsn. comprises 50-90 pts.wt. polypropylene resin and 10-40 pts.wt. ethylene-α-olefin copolymer whose total ethylene content is 55wt.% or higher, the ratio of the ethylene content of xylene soluble component at 25 deg.C to the total ethylene content of the copolymer is 0.90 or higher, and the component having a mol.wt. by GPC of 10,000 or lower accounts for 10wt.% or lower of the copolymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has high rigidity, high heat resistance,
The present invention relates to a polypropylene resin composition having excellent impact resistance.

[0002]

2. Description of the Related Art Isotactic crystalline polypropylene (hereinafter abbreviated as PP) is excellent in rigidity, surface gloss and heat resistance, but is inferior in low temperature impact resistance required for industrial materials. have. As a method of improving impact resistance, a method of adding an amorphous rubber-like substance by blending or multistage polymerization is widely used. However, these modifications have a drawback that the original characteristics of polypropylene such as rigidity, surface hardness and heat resistance are lowered. In particular, the heat resistance sharply decreases as the amount of rubber component added increases.

Many attempts have been made to use fillers such as talc and glass fiber for the purpose of improving the impact resistance of PP materials containing rubber. However, no satisfactory material has been obtained. Therefore, in order to improve the impact resistance while maintaining the heat resistance, it is desirable to develop the impact resistance with the least amount of rubber. Known means for achieving this include reinforcing the interface between the matrix PP and the rubber and finely dispersing the rubber. As a reinforcement of the interface, one using a graft reaction is also proposed (Lohse et.al., Macromolecule
s, 24, 561 (1991)), but satisfactory results have not been obtained due to generation of gel, decrease in MFR, etc. Fine dispersion has been proposed as another means for improving impact resistance with a smaller amount of rubber. Wu (Wu, Polymer, 26,1855 (1
985)), in a system in which rubber (EPDM) is dispersed in nylon, impact resistance is governed by the distance between rubber dispersed particles. It has been shown that this is also true for the PP / ethylene propylene rubber (EPR) system (Akiyoshi et.a.
L., Polymer Preprints, 39, 3699 (1990)). In order to reduce the distance between the particle walls with the same amount of rubber, it is necessary to finely disperse the rubber. In order to achieve fine dispersion in the PP / EPR system, E, which is compatible with PP and has a relatively low ethylene content, is used.
It seems that blending PR is effective, but it is considered that a part of the rubber component dissolves in the PP phase, and the heat resistance deteriorates as described above.

The most effective method for achieving fine dispersion is to obtain a so-called block copolymer by a multistage polymerization method in which a rubber component is polymerized after PP. However, even with this method, what is particularly satisfactory in heat resistance has not been obtained. In order to obtain a highly heat resistant block copolymer by multistage polymerization, a titanium-based catalyst is generally used. The rubber component of a polymer obtained by using a conventional titanium-based catalyst contains a large amount of those lower than CE represented by the average value (so-called composition distribution is wide), and the molecular weight distribution is sufficiently narrow. Since it is not present, it is considered that the heat resistance is deteriorated as a result of a part of the rubber component being dissolved in the PP phase.

[0005]

The object of the present invention is to prevent the dissolution of the rubber component in the PP phase and at the same time achieve fine dispersion, resulting in high rigidity and high heat resistance while maintaining resistance. It is intended to provide a polypropylene resin composition having excellent impact properties.

[0006]

The object of the present invention comprises 50 to 90 parts by weight of a polypropylene resin and 10 to 40 parts by weight of an ethylene-α-olefin copolymer.
-The ethylene content of the olefin copolymer is 55 wt% or more, and the xylene-soluble component C at 25 ° C relative to the ethylene content (CE) of the ethylene-α-olefin copolymer is C
This is achieved by a polypropylene-based resin composition in which the ratio of E is 0.90 or more and the content of the component having a molecular weight of 10,000 or less determined by GPC of the ethylene-α-olefin copolymer is 10 wt% or less.

The polypropylene resin used in the present invention is mainly composed of isotactic polypropylene (abbreviated as homo PP) or propylene in a small amount (usually 1
It is a random copolymer of α-olefin such as ethylene and butene-1 (0 wt% or less), but homo PP is preferable from the viewpoint of rigidity and heat resistance.

In the present invention, the ethylene-α-olefin copolymer has an ethylene content (CE) of 55 wt.
% Or more, preferably 60 wt% or more, and more preferably 65 wt% or more. The ratio of CE of the xylene solubles at 25 ° C to the ethylene content (CE) is 0.9.
It is 0 or more (soluble matter CE / polymer CE> 0.9), preferably 0.95 or more. Further, a component having a molecular weight of 10,000 or less determined by GPC of 10 wt% or less, preferably 5 wt% or less is used as a rubber component, and the ethylene-α-olefin copolymer has a number average particle diameter of 2
It is desirable to disperse in homo PP when the particle size is not more than μm.

As such an ethylene-α-olefin copolymer, any of titanium-based, vanadium-based and metallocene-based copolymers may be used. Particularly, those copolymerized with a metallocene-based catalyst are the above-mentioned copolymers. Desirable to get. Since the copolymer obtained by the conventional titanium-based catalyst has a wide composition distribution and the molecular weight distribution is not narrow enough, even if the ethylene content (CE) of the copolymer is 55 wt% or more, a part thereof is dissolved in the PP phase. As a result, heat resistance deteriorates. The ethylene content (CE) of the copolymer is 55 wt% or less, or the ratio of CE of the xylene-soluble component at 25 ° C. to the ethylene content (CE) is less than 0.90, or the molecular weight determined by GPC of 10, If the content of 000 or less is more than 10 wt%, the rigidity and heat resistance deteriorate.

The metallocene catalyst referred to herein is a catalyst system represented by Kaminsky catalyst (metallocene / methylaluminoxane) widely known as a homogeneous catalyst for olefin polymerization. A method for producing an ethylene-α-olefin copolymer is described in, for example, JP-A-58-193.
Japanese Patent Publication No. 09 discloses a method for producing ethylene and a copolymer of ethylene and another α-olefin using biscyclopentadienyl zirconium dichloride and linear or cyclic methylaluminoxane as catalysts. Also,
In the polymerization of propylene, it has been known that stereospecific polymerization is possible (JP-A-58-19309).
JP-A-2-76887).

As a method for obtaining the polypropylene resin and the rubber component of the present polymer, there are blending and multistage polymerization. When the blending method is used, the catalyst system that gives the polypropylene resin may be either a metallocene or a titanium system (magnesium-supporting type, TiCl ₃ type), but a highly stereoregular one is preferable. Further, if necessary, those having a broadened molecular weight distribution by blending, multistage polymerization or the like may be used. Catalytic systems that give the above-mentioned rubber components include titanium-based, metallocene-based, and vanadium-based catalysts, but the metallocene-based catalysts are preferable for the above reasons. The blending may be carried out using either a single-screw or twin-screw extruder, but it is preferable to use a twin-screw extruder with sufficient kneading. As a catalyst when using multi-stage polymerization, there are titanium-based, metallocene-based, and vanadium-based catalysts,
Preferably, the metallocene system should be used.

In the present invention, in order to enhance the effects of the invention, it is preferable to use a dispersion accelerator. Conventionally, a method of using a dispersion accelerator such as SBR is used to achieve fine dispersion. However, usually these additions significantly deteriorate the heat resistance. In the present invention, these dispersion accelerators may be used, but the dispersion accelerator effective for the purpose of the present invention has [η] of 2.0 or more, preferably 4.0 or more and a propylene content of 50 wt. % Or more, preferably 60 wt% or more of ethylene-propylene copolymer or block copolymer of olefinic block copolymer containing hydrogenated butadiene block.
It is desirable to use 10 to 10 wt%. When the [η] of the ethylene-propylene copolymer is less than 2.0, rigidity and heat resistance are deteriorated, and if the propylene content is less than the values shown above, there is no effect as a dispersion accelerator. The amount of dispersion promoter is 1w
At t% or less, the effect is not exhibited. When it is 10 wt% or more, heat resistance is deteriorated. More preferably, 2-5w
t%.

As the catalyst system for obtaining the ethylene-based copolymer used as the dispersion accelerator, any of titanium-based (magnesium-supported system, TiCl ₃ -based), metallocene-based and vanadium-based catalysts may be used. Any dispersion accelerator can be added after kneading in an extruder, but among the dispersion accelerators, the ethylene-based copolymer can also be added by multistage polymerization.

In the polypropylene resin composition of the present invention, if necessary, all additives such as a thermal oxidation stabilizer, a nucleating agent, a light stabilizer, an antistatic agent, a lubricant, etc., which are added to ordinary polypropylene, Also, radical initiators such as peroxides and modifiers such as unsaturated carboxylic acids can be used. Further, various polyethylene, polybutene, olefinic copolymers such as ethylene-butene copolymers, talc, calcium carbonate, lithium carbonate, mica, glass fibers and other inorganic fillers can be mixed and used. In particular, in order to improve rigidity and heat resistance, it is desirable to use a nucleating agent and a filler.

[0015]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto. Various physical properties were measured by the following methods. (1) [η] (Intrinsic Viscosity) Measurement It was measured at 135 ° C. using a dilute solution dissolved in tetralin. (2) Molecular weight distribution measurement Shodex was added to a Waters 150C type GPC device.
Two AT-80M / S columns were connected in series and used. 1,2,4-Trichlorobenzene containing 0.01% of BHT was used as a solvent, the sample was dissolved, and then filtered through a sintered metal filter of 0.5 μm, and measured at 140 ° C. The obtained chromatogram was calibrated using standard polystyrene. The molecular weight was calculated as polypropylene using the universal method. The weight fraction of each molecular weight was determined from the relationship between the obtained molecular weight and the elution amount. (3) Xylene-soluble component The xylene-soluble component as referred to herein means a part which is completely dissolved in ortho-xylene at 130 ° C and then cooled at 25 ° C. (4) Ethylene content Measured by ¹³ C-NMR (400 MHz). (5) Measured by MFR JIS K-7210. (6) Izod impact strength It was performed using a notched test piece according to ASTM D256. (7) Flexural modulus It was measured according to JIS K-7207. (8) Measured according to HDT JIS K-7207. (9) Average Dispersion Particle Size The TOSPIX-U (trade name) manufactured by Toshiba was used as an image processing apparatus, and the average particle size was obtained from an actual image obtained from an electron microscope.

Reference Example 1 [Homo PPno Polymerization] Preparation of solid catalyst component Under a nitrogen atmosphere, anhydrous magnesium chloride 47.6 g (50
0 mmol), 259 ml decane and 2-ethylhex
234 ml (1.5 mol) of silalcohol at 130 ° C
After heating reaction for 2 hours to form a uniform solution,
11.1 g (75 mmol) of phthalic anhydride was added to
Stir and mix at 130 ° C for an additional 1 hour to remove phthalic anhydride.
Was dissolved in the homogeneous solution. Bring the resulting homogeneous solution to room temperature.
After cooling, titanium tetrachloride 2.0 kept at -20 ° C
The whole volume was dropped into 1 (18 mol) over 1 hour.
After completion of the dripping, the temperature of the mixed solution was increased to 110 ° C over 4 hours.
When the temperature rises and reaches 110 ° C, diisobutyl phthalate
Add 26.8 ml (125 mmol) of chill for 2 hours
The reaction was carried out at 110 ° C. with stirring. After completion of the reaction, hot filtration
A solid component was collected, and then the reaction mixture was charged with titanium tetrachloride.
After suspending 2.0 l (18 mol), 2 at 110 ° C
Allowed to react for hours. After the reaction was completed, the solid was filtered again while hot.
Collect the components and use 2.0 l of decane at 110 ° C 7 times at room temperature.
It was washed 3 times with 2.0 l of hexane. Prepolymerization In an autoclave with an internal volume of 3 l under a nitrogen atmosphere,
500 ml of n-heptane, triethylaluminum 6.
0 g (0.053 mol), t-butyl trimethoxy
Orchid 3.1 g (0.017 mol), and obtained above
100 g of solid catalyst component was added and the temperature range was from 0 to 5 ° C.
And stirred for 5 minutes. Next, 10 g of solid component per 1 g of
Autoclave propylene to polymerize ropylene
It was fed in and prepolymerized for 1 hour in the temperature range of 0 to 5 ° C.
The obtained prepolymerized catalyst was treated with 500 ml of n-heptane three times.
It was washed and used in the following polymerization. Polymerization of propylene Autoclave with a stirrer and an internal volume of 60 l under a nitrogen atmosphere
Polymerization was carried out as follows using one machine. Those above
Prepolymerization catalyst component 2.0 g prepared by the method, triethyl
Aluminum 11.4 g (100 mmol), t-butyl
5.9 g (33 mmol) of rutrimethyloxysilane
Then 18 kg of propylene and the MFR of the polymer was 3
Supply hydrogen to 0 and polymerize at 70 ° C for 30 minutes.
went. Target polypropylene by purging unreacted gas
Got

Reference Example 2 [Rubber component 1 (EPR polymerized with metallocene catalyst)] 6 L of dehydrated toluene was charged into a 6 L autoclave, and a methylalumoxane toluene solution (molecular weight: 1026) manufactured by Tosoh Akzo Co., Ltd. was used as Al atom at 380 mmol. In addition, 30 ml of a toluene solution containing 1.9 × 10 ^-2 mmol / ml of ethylenebis (indenyl) zirconium chloride (Et (Ind) ₂ ZrCl ₂ ) was added, and the mixture was stirred at room temperature for 10 minutes. After cooling the temperature of the autoclave to 2 ° C., an ethylene / propylene (molar ratio 7/3) mixed gas was introduced into the autoclave using a mass flow meter, and polymerization was carried out at this temperature for 1 hour. After the polymerization, the contents were put into a large amount of methanol-hydrochloric acid to separate the produced -propylene copolymer, and the solvent was removed from the polymer at 50 ° C under reduced pressure. Yield is 1
It was 50 g. The ethylene content (CE) of the obtained ethylene copolymer was 70 wt%, based on the CE of the copolymer,
The CE ratio of the xylene-soluble component at 25 ° C. is 0.98,
2w for components with molecular weight less than 10,000 determined by GPC
It was t%.

Reference Example 3 [Rubber component 2 (EPR)] Preparation of solid catalyst component Under a nitrogen atmosphere, anhydrous magnesium chloride 47.6 g (50
0 mmol), 259 ml decane and 2-ethylhex
234 ml (1.5 mol) of silalcohol at 130 ° C
After heating reaction for 2 hours to form a uniform solution,
11.1 g (75 mmol) of phthalic anhydride was added to
Stir and mix at 130 ° C for an additional 1 hour to remove phthalic anhydride.
Was dissolved in the homogeneous solution. Bring the resulting homogeneous solution to room temperature.
After cooling, titanium tetrachloride 2.0 kept at -20 ° C
The whole volume was dropped into 1 (18 mol) over 1 hour.
After completion of the dripping, the temperature of the mixed solution was increased to 110 ° C over 4 hours.
When the temperature rises and reaches 110 ° C, diisobutyl phthalate
Add 26.8 ml (125 mmol) of chill for 2 hours
The reaction was carried out at 110 ° C. with stirring. After completion of the reaction, hot filtration
A solid component was collected, and then the reaction mixture was charged with titanium tetrachloride.
After suspending 2.0 l (18 mol), 2 at 110 ° C
Allowed to react for hours. After the reaction was completed, the solid was filtered again while hot.
Collect the components and use 2.0 l of decane at 110 ° C 7 times at room temperature.
It was washed 3 times with 2.0 l of hexane. Adjustment of TiCl ₄ [C ₆ H ₄ (COO ・ i-C ₄ H ₉ ) ₂ ]
Made Hexane containing 19 g (100 mmol) of titanium tetrachloride
27.8 g of diisobutyl phthalate (1
(00 mmol) was added dropwise for about 30 minutes while maintaining 0 ° C.
It was After completion of the dropping, the temperature was raised to 40 ° C. and the reaction was performed for 30 minutes.
After the reaction was completed, the solid component was collected and mixed with 500 ml of hexane.
It was washed twice to obtain the desired product.TiCl ₄ [C ₆ H ₄ (COO · i-C ₄ H ₉ ) ₂ ] By
Treatment of 40 g of the solid catalyst obtained above in 600 ml of toluene
Suspend at 25 ° C TiCl_Four [C₆ H_Four (COO ・ i-
C_Four H₉ )₂ ] 10.3 g (22 mmol) for 1 hour
I responded. After completion of the reaction, 200 ml of titanium tetrachloride (1.
(8 mol) was added, and the mixture was reacted at 110 ° C. for 2 hours. Anti
After completion of the reaction, collect the solid components by hot filtration and then
Toluene 600ml, titanium tetrachloride 200m
1 (1.8 mol) was suspended, and the suspension was allowed to stand at 110 for 2 hours.
I responded. After the reaction was completed, the solid components were collected by hot filtration again.
Then, take 1.0 liter of toluene at 110 ° C 7 times and wash at room temperature
Washed 3 times with 1.0 l of sun. Prepolymerization In an autoclave with an internal volume of 3 l under a nitrogen atmosphere,
500 ml of n-heptane, triethylaluminum 6.
0 g (0.053 mol), t-butyl trimethoxy
Orchid 3.1 g (0.017 mol), and obtained above
100 g of solid catalyst component was added and the temperature range was from 0 to 5 ° C.
And stirred for 5 minutes. Next, 10 g of solid component per 1 g of
Autoclave propylene to polymerize ropylene
It was fed in and prepolymerized for 1 hour in the temperature range of 0 to 5 ° C.
The obtained prepolymerized catalyst was treated with 500 ml of n-heptane three times.
It was washed and used in the following polymerization.Polymerization of ethylene-propylene copolymer Autoclave with a stirrer with an internal volume of 6.0 l under nitrogen atmosphere
Propylene 1344 g (32 mol) and hydrogen
1.54 mol% (300 kg / cm² ) Preparation 60 ℃
The temperature was raised to. N-hexa prepared in a pre-contact device
30 ml, triethylaluminum 400 molpp
m, dicyclopentylmethoxysilane 60 molppm
After contacting the mixture for 5 minutes, the above solid catalyst is further charged.
Contacted for minutes. Next, using a catalyst adding device,
Press the contact catalyst with ethylene and press
Pressure 10.4kg / cm² (15mol%) at 60 ° C
Polymerized for 30 minutes. Unreacted gas is purged and the target EP
R was obtained. The CE of the obtained copolymer was 56 wt%, E
Of the EPR component relative to the ethylene content (CE) of the PR component
The xylene solubles CE ratio at 25 ° C is 0.97, GP
Ingredients having a molecular weight of 10,000 or less determined by C are 4 wt%
Met.

Reference Example 4 [Rubber component 4 (EPR)] Polymerization of ethylene-propylene copolymer Using the same catalyst as the homo PP of Reference Example 1, as follows:
Polymerized. Under a nitrogen atmosphere, the internal volume was 6.0 liters with a stirrer.
Propylene 1344g (32mo
l), 1.54 mol% of hydrogen (300 kg / cm² )
The temperature was raised to 60 ° C. Prepared in the pre-contact device
N-hexane 30 ml, triethylaluminum 40
0 molppm, dicyclopentylmethoxysilane 60
After contacting with molppm for 5 minutes, the solid contact
The medium was charged and contacted for 5 minutes. Next, using a catalyst addition device
Press-fit the above pre-contact catalyst with ethylene.
And ethylene partial pressure 10.4 kg / cm² (15 mol
%) At 60 ° C. for 30 minutes. Unreacted gas
The desired EPR was obtained. EPR of the obtained copolymer
The ethylene content (CE) of the component is 55wt%,
The ratio of CE of the xylene-soluble component of the EPR component at 25 ° C is
0.85, 10,000 or less of the molecular weight determined by GPC
The component was 12 wt%.

Reference Example 5 [Dispersion Promoter 1 (Ethylene-Propylene Copolymer)] Polymerization was carried out as follows using the same catalyst as the homo PP of Reference Example 1. Under a nitrogen atmosphere, 1344 g (32 mol) of propylene in an autoclave with an internal volume of 6.0 l and a stirrer,
Hydrogen was charged at 0.67 mol% (130 kg / cm ² ) and the temperature was raised to 60 ° C. N- prepared in the pre-contact device
Hexane 30 ml, triethylaluminum 400 mo
1 ppm, dicyclopentylmethoxysilane 60 mol
After contacting with ppm for 5 minutes, the above solid catalyst was further charged and contacted for 5 minutes. Next, the above pre-contact catalyst was press-fitted with ethylene using a catalyst adding device, and the ethylene partial pressure was 5.2 kg / cm ² (7.0 mol%).
Polymerization was carried out at 0 ° C for 30 minutes. Unreacted gas was purged to obtain the desired EPR. The value of [η] of the obtained EPR is 4.
1. The propylene content was 65 wt%.

Examples 1 and 2 In addition to the rubber component 1 of Reference Example 2 and homo PP of Reference Example 1, 0.08 part by weight of BHT, which is a commercially available stabilizer, and Irganox 10 were used.
0.05 to 10 parts by weight, calcium stearate 0.0
1 part by weight and 0.4 parts by weight of APBB as a nucleating agent were added, and the mixture was melt-kneaded at 200 ° C. using a twin-screw extruder (KTX-37). A test piece was prepared using the obtained composition, and the physical properties were measured. The results are shown in Table 1.

Example 3 Rubber component 1 of Reference Example 2 and dispersion accelerator 1 of Reference Example 5 (6w
t%), 0.08 part by weight of BHT, which is a commercially available stabilizer,
A twin-screw extruder (KTX) was added with 0.05 parts by weight of Irganox 1010 and 0.01 parts by weight of calcium stearate.
-37) was melt-kneaded at 200 ° C. to prepare a masterbatch. The obtained masterbatch, Reference Example 1
Homo-PP and APBB as a nucleating agent were melt-kneaded using the same twin-screw extruder. A test piece was prepared using the obtained composition, and the physical properties were measured. The results are shown in Table 1.

Examples 4 and 5 Rubber component 1 and dispersion accelerator 2 of Reference Example 2 (E6100P:
A triblock copolymer manufactured by Japan Synthetic Rubber Co., Ltd. (5 wt% in Example 4 and 3 wt% in Example 5), 0.08 part by weight of a commercially available stabilizer BHT, and 0.05 part by weight of Irganox 1010. , 0.01 parts by weight of calcium stearate was added to 200 using a twin-screw extruder (KTX-37).
The mixture was melt-kneaded at 0 ° C to prepare a masterbatch. The obtained masterbatch, homo PP of Reference Example 1, A as a nucleating agent
PBB was melt-kneaded using the same twin-screw extruder. A test piece was prepared using the obtained composition, and the physical properties were measured. The results are shown in Table 1.

Example 6 Into the rubber component 2 of Reference Example 3 and the homo PP of Reference Example 1, 0.08 part by weight of a commercially available stabilizer BHT, and Irganox 10 were used.
0.05 to 10 parts by weight, calcium stearate 0.0
1 part by weight and 0.4 parts by weight of APBB as a nucleating agent were added, and the mixture was melt-kneaded at 200 ° C. using a twin-screw extruder (KTX-37). A test piece was prepared using the obtained composition, and the physical properties were measured. The results are shown in Table 1.

Example 7 Homo PP of Reference Example 1 and Rubber Component 1 similar to Examples 1-5
And dispersion accelerator 2 (E6100P: triblock copolymer manufactured by Japan Synthetic Rubber Co., Ltd.) (15 wt%), and 0.08 part by weight of BHT, which is a commercially available stabilizer, and Irganox 1010.
0.05 part by weight and 0.01 part by weight of calcium stearate were added, and the amount was adjusted to 20 using a twin-screw extruder (KTX-37).
The mixture was melt-kneaded at 0 ° C. to prepare a masterbatch. The obtained masterbatch, homo PP, and APBB as a nucleating agent were melt-kneaded using the same twin-screw extruder. A test piece was prepared using the obtained composition, and the physical properties were measured. The results are shown in Table 1.

[0026]

[Table 1]

Example 8 As in Examples 1 and 2, the rubber component 1 was used and the nucleating agent (APB
Table 2 shows an example of using 15 wt% of talc instead of B).

Examples 9 and 10 Table 2 shows an example in which the rubber component 1 and the dispersion accelerator 1 were used in the same manner as in Example 3 and 15 wt% of talc was used instead of the nucleating agent (APBB).

Examples 11 and 12 Table 2 shows an example in which the rubber component 1 and the dispersion accelerator 2 were used in the same manner as in Examples 4 and 5, and 15 wt% of talc was used instead of the nucleating agent (APBB).

Comparative Examples 1 and 2 In homo-PP of Reference Example 1 and rubber component 3 (EP1: EPR manufactured by Japan Synthetic Rubber Co., ethylene content 51 wt%), 0.08 part by weight of a commercially available stabilizer BHT, and Irganox 10 were used.
0.05 to 10 parts by weight, calcium stearate 0.0
1 part by weight and 0.4 parts by weight of APBB as a nucleating agent were added, and the mixture was melt-kneaded at 200 ° C. using a twin-screw extruder (KTX-37). A test piece was prepared using the obtained composition, and the physical properties were measured. The results are shown in Table 1 together with the examples.

Comparative Example 3 The rubber component 4 of Reference Example 4 was added to the commercially available stabilizer BHT0.
08 parts by weight, 0.05 parts by weight of Irganox 1010, 0.01 parts by weight of calcium stearate, and 0.4 parts by weight of APBB as a nucleating agent were added to the twin-screw extruder (KTX-3).
7) was used and melt-kneaded at 200 ° C. A test piece was prepared using the obtained composition, and the physical properties were measured. The results are shown in Table 1 together with the examples.

Comparative Example 4 An example in which the same rubber component 4 as in Comparative Example 3 was used and 15 wt% of talc was used instead of the nucleating agent (APBB) is shown in Table 2 together with Examples.

[0033]

[Table 2]

[0034]

EFFECTS OF THE INVENTION The polypropylene resin of the present invention achieves fine dispersion as well as suppression of dissolution of the rubber component into the PP phase, and as a result, impact resistance while maintaining high rigidity and high heat resistance. Is also excellent.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigenobu Miyake, Oita City, Oita Prefecture, No. 2 Nakasu, Showa Denko K.K.

Claims (4)

[Claims] 1. A polypropylene resin of 50 to 90 parts by weight,
10 to 40 parts by weight of the ethylene-α-olefin copolymer, the ethylene content of the ethylene-α-olefin copolymer is 55 wt% or more, and the ethylene content of the ethylene-α-olefin copolymer (CE) is 25%. Xylene solubles CE ratio of 0.90 or more, ethylene-
The molecular weight of 1 determined by GPC of α-olefin copolymer
A polypropylene-based resin composition containing 10% by weight or less of 50,000 or less components. 2. The polypropylene-based resin composition according to claim 1, wherein the ethylene-α-olefin copolymer dispersed in the polypropylene resin has a number average particle diameter of 2 μm or less. 3. The polypropylene resin composition according to claim 1, wherein a metallocene catalyst is used as a polymerization catalyst for the ethylene-α-olefin copolymer. 4. An ethylene-propylene copolymer having an [η] of 2.0 or more and a propylene content of 50 wt% or more, or an olefinic block copolymer containing a block of hydrogenated butadiene, as the dispersion accelerator. The propylene-based resin composition according to claim 1, which is used in an amount of 1 to 10 wt%.