JPH0598128A - Resin composition for automobile - Google Patents

Abstract

PURPOSE:To obtain the subject composition excellent in paintability, moldability, etc., by compounding a multi-stage polymerized propylene-ethylene block copolymer with specific amounts of an ethylene-propylene copolymer rubber, an ethylene-butene copolymer rubber and talc. CONSTITUTION:The objective composition is produced by compounding (A) 40-60wt.% of a propylene-ethylene block copolymer produced by multi-stage polymerization, (B) 10-20wt.% of an ethylene-propylene copolymer rubber, (C) 10-20wt.% of an ethylene-butene copolymer rubber and (D) 15-30wt.% of talc having an average particle diameter of <=1.5mum. The sum of the components B and C is 20-30wt.% and the component A contains 4-10wt.% (based on 100wt.% of the component A) of propylene-ethylene random copolymer part (having an intrinsic viscosity of >=4.0dl/g and an ethylene content of 30-70wt.%) and a propylene homopolymer part having an intrinsic viscosity of 0.9-1.2dl/g. The ratio of the intrinsic viscosity of the homopolymer part to that of the resin component other than the homopolymer part is 0.1-2.5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for automobiles, which is particularly excellent in paintability and moldability and has a good balance of impact resistance, mechanical strength, heat distortion resistance, brittle temperature, hardness, etc. The present invention also relates to an automotive resin composition having a small molding shrinkage ratio and a small linear expansion coefficient.

[0002]

2. Description of the Related Art Polypropylene is widely used in various fields because it is lightweight and excellent in mechanical strength and the like. However, since it is inferior in impact resistance, various rubbers such as ethylene-propylene copolymer rubber (EPR) and other inorganic fillers such as talc are added to the propylene-ethylene block copolymer for the purpose of improving the impact resistance. Polypropylene resins have been proposed.

Japanese Unexamined Patent Publication No. 61-12742 discloses (a) ethylene content 2
~ 3 wt%, melt flow rate 40-45 g / 10 min propylene-ethylene block copolymer 62-57 wt%, (b)
Ethylene content 70-80% by weight, Mooney viscosity ML _{1 + 4} (100
° C) 55-58 ethylene-propylene copolymer rubber 26-28
% By weight, (c) density 0.955 to 0.960 g / cm ³ , high density polyethylene 2 to 3% by weight, melt flow rate 18 to 22 g / 10 min, (d) average particle size 1.8 to 2.2 μm, specific surface area 36000 to 42
000 cm ² / g of talc 10-12% by weight, melt flow rate 13-18 g / 10 min, density 0.950-0.980 g / cm ³ ,
Flexural modulus 11500 to 14000 kg / cm ² , linear expansion coefficient between 20 and 80 ° C 7 × 10 ^-5 to 10 × 10 ^-5 cm / cm / ° C and JIS-Z8741
Disclosed is a resin composition having a surface gloss of 55% or more measured by a 60 ° -60 ° method.

JP-A-1-149845 discloses that (a) 5 to 12% by weight of a boiling xylene-soluble component having an ethylene content of 20 to 60% by weight and an ethylene content of the whole polymer of 1 to 7% by weight. And 59-74% by weight of propylene-ethylene block copolymer having a melt flow rate of 15-50 g / 10 min, and (b) propylene content of 20-60% by weight and Mooney viscosity ML _{1 + 4} (100 ° C).
100-150 ethylene-propylene copolymer rubber 35
Disclosed is -20% by weight, and (c) 3-6% by weight of talc having a specific surface area of 30,000 cm ² / g or more and an average particle size of 0.5 to 2.0 µm. is doing.

However, JP-A-61-2742 and JP-A-61-12742
Each of the resin compositions of 1-149845 easily causes thermal deformation, and when used in a bumper, for example, the bumper easily deforms due to a difference in linear expansion coefficient between the bumper and a vehicle body when placed in a high temperature environment. Therefore, there is a problem that the appearance may be impaired.

Further, in the system composed of the propylene-ethylene block copolymer, the ethylene-propylene copolymer rubber (and high-density polyethylene) and talc as described above, the propylene-ethylene block copolymer and the ethylene-polymer are generally used. By adjusting the ratio of ethylene and propylene in the propylene copolymer rubber, the molecular weight, etc., a composition having fluidity suitable for each application is obtained. However, in the method as described above, all the physical properties such as coatability, moldability, rigidity, ductility, heat distortion resistance, embrittlement temperature, and hardness are at a good level as a resin for automobiles, a so-called well-balanced composition. There is a problem that it is difficult to make things.

Therefore, as a result of various investigations by the present inventors on resin compositions used for interior materials, exterior materials, etc. of automobiles,
As the propylene-ethylene block copolymer, one obtained by multistage polymerization is used, and ethylene-
It has been found that those using two types of rubber components, a propylene copolymer rubber and an ethylene-butene copolymer rubber, have good physical properties. Furthermore, the present inventors have found that even in the system of the above resin component, the component constitution of the multi-stage polymerized propylene-ethylene block copolymer is variously changed, and the propylene homopolymer portion in the composition and other resin components are It has been found that the characteristics of the obtained composition are significantly changed by specifying the ratio of the intrinsic viscosity of.

Therefore, an object of the present invention is that the coating properties and moldability are excellent, and the balance of impact resistance, mechanical strength, heat distortion resistance, embrittlement temperature, hardness, etc. is good, and the molding shrinkage ratio and the linear shrinkage are excellent. An object of the present invention is to provide an automotive resin composition having a low expansion coefficient.

[0009]

In view of the above problems, the present inventors have found that a multi-stage polymerized propylene-ethylene block copolymer, an ethylene-propylene copolymer rubber, an ethylene-butene copolymer rubber, and talc are used. As a result of diligent research on how the component constitution of the multi-stage polymerized propylene-ethylene block copolymer affects various physical properties of the composition containing the respective propylene-ethylene random copolymer portion. Amount, the intrinsic viscosity of the propylene homopolymer portion, the intrinsic viscosity of the propylene-ethylene random copolymer portion, and the ethylene content in the propylene-ethylene random copolymer portion are multistage polymerized so as to be within a predetermined range. To produce a propylene-ethylene block copolymer with an appropriate amount of ethylene-propylene copolymer system Rubber and an ethylene-butene copolymer rubber are blended, and the intrinsic viscosity of the propylene homopolymer portion in the composition and the ratio of the intrinsic viscosity of the other resin components are specified as a resin for automobiles, particularly The present invention has been found out that it is suitable as a resin for interiors and hard exteriors.

That is, the resin composition for automobiles of the present invention comprises (a) 40 to 60% by weight of a propylene-ethylene block copolymer obtained by multistage polymerization, and (b) an ethylene-propylene copolymer rubber 10 to 20. Wt% and (c) ethylene-
10 to 20% by weight of butene copolymer rubber, and (d) more than 15% by weight and 30% by weight or less of talc, and (b) +
A resin composition for automobiles, wherein the total of (c) is 20 to 30% by weight, wherein the propylene-ethylene block copolymer is 4 to 10% by weight per 100% by weight of the propylene-ethylene random copolymer. Part (the intrinsic viscosity is 4.0 dl / g or more, the ethylene content in the propylene-ethylene random copolymer part is 30 to 70% by weight) and the intrinsic viscosity is 0.9
Containing ~ 1.2 dl / g propylene homopolymer part,
The ratio (A / B) of the intrinsic viscosity (A) of the propylene homopolymer portion and the intrinsic viscosity (B) of the resin component other than the propylene homopolymer portion is within a range of 0.1 to 2.5. ..

The present invention is described in detail below. In the present invention, (a) propylene-ethylene block copolymer,
It is synthesized by multistage polymerization.

The propylene-ethylene block copolymer synthesized by the above multi-stage polymerization is composed of a substantially crystalline homopolypropylene portion, a propylene-ethylene random copolymer portion, and a small amount of a polyethylene portion in some cases. And each part may exist as a single polymer, or may be in a state where each part is bonded. The above-mentioned parts are basically composed of propylene and / or ethylene, but may contain a small amount of other α-olefin, diene-based monomer or the like.

Examples of the propylene homopolymer portion include a propylene homopolymer or a propylene copolymer containing a small amount of a comomer component. Examples of the comonomer component include other α-olefins such as ethylene, butene-1, octene-1, and diene-based monomers.

The intrinsic viscosity [η] _H of the propylene homopolymer part is 0.9 to 1.2 dl / g. Intrinsic viscosity 0.9dl / g
If it is less than 1.2, the ductility is insufficient, and if it exceeds 1.2 dl / g, the fluidity of the composition is insufficient.

The propylene-ethylene random copolymer portion is a low crystalline portion and has a content of ethylene of
30 to 70% by weight. If the ethylene content is less than 30% or more than 70% by weight, ductility is particularly insufficient.
Further, the propylene-ethylene random copolymer may contain a small amount of a comonomer component. Examples of the comonomer component include other α-olefins such as ethylene, butene-1, octene-1, and diene-based monomers. Intrinsic viscosity of the propylene homopolymer part [η]
_CXS is 4.0dl / g or more. If the intrinsic viscosity is less than 4.0 dl / g, the impact resistance is not sufficiently improved. The preferred intrinsic viscosity is 4 to 10 dl / g.

The content of ethylene in the whole propylene-ethylene block copolymer is 2 to 10% by weight, preferably 2 to 5% by weight. Regarding the content of the crystalline propylene homopolymer part and the propylene-ethylene random copolymer part, the total of + is 100% by weight, and the propylene homopolymer part is
90 to 96% by weight, and the propylene-ethylene random copolymer portion is 4 to 10% by weight. If it is out of the above range, the balance of physical properties is deteriorated. Even if it contains an ethylene homopolymer part, it is about 5% by weight or less.

In the multistage polymerization as described above, propylene is first polymerized in the presence of a Ziegler catalyst or the like to form a crystalline propylene homopolymer portion (which may contain a small amount of comonomer component), and At the stage, ethylene + propylene is switched to produce a random copolymer part.

Melt flow rate (MFR, 230 ° C., 2. of the above multistage polymerized propylene-ethylene block copolymer)
16 kg load) is preferably 40 to 120 g / 10 minutes, especially 60 to 10
0 g / 10 minutes is preferred. If the MFR value is less than 40 g / 10 min, the moldability of the obtained composition, particularly the injection moldability, will deteriorate.
Further, if it exceeds 120 g / 10 minutes, the mechanical strength is lowered, which is not preferable.

In the present invention, the ethylene-propylene copolymer rubber (b) includes ethylene-propylene copolymer rubber (EPR), and an ethylene-propylene-diene copolymer rubber (EPR) obtained by copolymerizing this with a diene compound. EPDM). The ethylene-propylene copolymer rubber is
The ethylene content is preferably 50 to 90 mol%, and the propylene content is preferably 50 to 10 mol%. More preferable ranges are 70 to 80 mol% for ethylene and 30 to 20 mol% for propylene. In the case of ethylene-propylene-diene copolymer rubber (EPDM), examples of the diene compound include ethylidene norbornene, dicyclopentadiene and 1,4-hexadiene.

The melt flow rate (MFR, 230 ° C., 2.16 kg load) of such ethylene-propylene copolymer rubber is preferably 0.5 to 20 g / 10 minutes, more preferably 0.5 to 10 g / 10 minutes. is there.

In the present invention, (c) ethylene-butene copolymer rubber (EBR) means that the ethylene content is 70 to 90.
Mol%, butene-1 content is a block copolymer of 30 to 10 mol%, particularly ethylene content of 75 to 85 mol%,
The butene-1 content is preferably 15 to 25 mol%. EBR may be copolymerized in a small amount with other α-olefins such as hexene-1 and octene-1 other than ethylene and butene-1, and diene compounds such as ethylidene norbornene and dicyclopentadiene.

EBR melt index (MI, 190
C., 2.16 kg load) is preferably 1 to 30 g / 10 minutes, more preferably 1 to 20 g / 10 minutes.

In the present invention, (d) talc is generally used as a filler / reinforcing agent for resins and the like. However, in the present invention, it is preferable to use talc having an average particle diameter of 1.5 μm or less. If the average particle size of talc exceeds 1.5 μm, mechanical strength such as flexural modulus and dimensional stability decrease, which is not preferable. Here, the average particle size is the particle size when the particle size distribution curve obtained by the integrating sieve intersects the 50% line.

The mixing ratio of various components as described above is
(a) The multi-stage polymerized propylene-ethylene block copolymer
40-60 wt%, preferably 45-55 wt%, (b) ethylene-propylene copolymer rubber 10-20 wt%, preferably 12-17 wt%, (c) ethylene-butene The polymer rubber is 10 to 20% by weight, preferably 10 to 15% by weight, and (d) talc is more than 15% by weight and 30% by weight or less, preferably 20 to 30% by weight.

(A) The elongation of the resulting composition when the multistage polymerized propylene-ethylene block copolymer is less than 40% by weight,
Hardness and the like tend to decrease, and when it exceeds 60% by weight, impact resistance decreases.

(B) When the ethylene-propylene copolymer rubber is less than 10% by weight, tensile properties such as tensile elongation at break and impact strength are lowered, and when it exceeds 20% by weight, mechanical properties such as hardness and flexural modulus are decreased. Strength is reduced.

(C) When the ethylene-butene copolymer rubber is less than 10% by weight, the hardness is lowered, and when it exceeds 20% by weight,
Mechanical strength such as flexural modulus decreases.

Further, (d) if the content of talc is 15% by weight or less, mechanical properties such as flexural modulus and heat distortion resistance are not sufficient, and if it exceeds 30% by weight, impact resistance, tensile elongation, etc. Ductility is reduced.

However, in the present invention, the component (b) and
Regarding the component (c), the total composition is 100% by weight,
The total of them ((b) + (c)) is 20 to 30% by weight. When (b) + (c) is less than 20% by weight, tensile properties such as tensile elongation at break and impact strength are lowered, and when it exceeds 30% by weight, flexural modulus, hardness, heat distortion resistance and various physical properties are balanced. Becomes worse.

Further, the composition of the present invention has an intrinsic viscosity (A) of the propylene homopolymer portion in the composition,
The ratio (B / A) of the intrinsic viscosity (B) to other resin components is 0.1.
Must be in the range of ~ 2.5. If the ratio of the intrinsic viscosity is out of the above range, the molding shrinkage rate and the linear expansion rate of the injection-molded product increase, and the dimensional stability deteriorates. In particular, it is not possible to obtain a product having good dimensional stability, such as a molding shrinkage ratio of 6/1000 or less and a linear expansion coefficient of 7 × 10 ^-5 ° C ^-1 or less, which is required for a large-sized molded product.

For the separation of the propylene homopolymer part, for example, the composition is dissolved in boiling xylene, talc is separated as an insoluble part, and after cooling, the propylene homopolymer part and the ethylene homopolymer part are separated as an insoluble part. The insoluble portion may be reheated to 100 ° C. to remove the ethylene homopolymer portion, and this may be performed.

The automotive resin composition of the present invention may also contain other additives such as a heat stabilizer for the purpose of modifying the resin composition.
Antioxidant, light stabilizer, flame retardant, plasticizer, antistatic agent,
A release agent, a foaming agent, etc. can be added.

The composition of the present invention is a single-screw extruder,
It can be obtained by melt-kneading at 150 to 300 ° C, preferably 190 to 250 ° C using an extruder such as a twin-screw extruder.

[0034]

The resin composition for automobiles of the present invention contains a predetermined amount of a multi-stage polymerized propylene-ethylene block copolymer, an ethylene-propylene copolymer rubber, an ethylene-butene copolymer rubber, and talc. In the composition comprising, as a multi-stage polymerized propylene-ethylene block copolymer, a propylene homopolymer part, a propylene-ethylene random copolymer part, and an ethylene homopolymer part are contained in a specific ratio, and a propylene homopolymer part is contained. And the intrinsic viscosity of the ethylene homopolymer part,
The intrinsic viscosity of the propylene-ethylene random copolymer portion and the ethylene content of the propylene-ethylene random copolymer portion within a predetermined range are used, and the intrinsic viscosity of the propylene homopolymer portion in the composition is further used. A resin having a ratio of the intrinsic viscosity of the other resin component to the intrinsic viscosity within a predetermined range is used. Such an automotive resin composition of the present invention is excellent in paintability and moldability, and has a good balance of impact resistance, mechanical strength, heat distortion resistance, embrittlement temperature, hardness, etc. The molding shrinkage rate and linear expansion rate of the product are also small.

Although the reason why such an effect is obtained is not always clear, the multi-stage polymerized propylene-ethylene block copolymer has good compatibility with the olefin elastomer, and the ethylene-propylene copolymer is added thereto. The combined use of two types of rubbers, a system rubber and an ethylene-butene copolymer rubber, can improve hardness and flexibility without lowering impact resistance, tensile properties, etc., and further multi-stage polymerized propylene-ethylene. By making the block copolymer of the component constitution of the present invention, and specifying the ratio of the intrinsic viscosity of the propylene homopolymer portion and the other resin component in the composition, and controlling the dispersion structure of each component, Moldability, heat distortion resistance, embrittlement temperature, improved hardness and dimensional stability of molded products are obtained. Furthermore, by containing talc, mechanical strength is improved. Etc. are further improved, the balance of various physical properties are believed to be due to a suitable automotive interiors, and as a rigid covering material with.

[0036]

The present invention will be described in more detail by the following examples. The following resins and talc were used as raw materials. [1] Two-stage polymerized propylene-ethylene block copolymer Various two-stage polymerized propylene-ethylene block copolymers having the properties shown in Table 1 were prepared. Table 1 MFR ⁽¹⁾ [η] _H ⁽²⁾ [η] _CXS ⁽³⁾ Cv ⁽⁴⁾ Gv ⁽⁵⁾ Species (g / 10 min) (dl / g) (dl / g) (% by weight ) ) (Wt%) BPP-1 60.0 1.0 4.6 8.0 50 BPP-2 70.0 0.9 5.1 8.0 50 BPP-3 60.0 1.1 4.0 6.0 50 BPP-4 70.0 1.0 4.5 6.0 50 BPP-5 60.0 1.2 4.4 5.0 50 BPP-6 70.0 1.0 4.8 5.0 50 BPP-7 70.0 1.2 4.0 13.0 60 BPP-8 40.0 1.2 2.7 13.0 50 Note) (1) MFR: Measured by ASTM D1238 at 230 ° C under 2.16kg load. (2) [η] _H : Intrinsic viscosity of homo moieties (propylene homopolymer moieties and ethylene homopolymer moieties) in a propylene-ethylene block copolymer. (3) [η] _CXS : Intrinsic viscosity of the copolymerized portion (propylene-ethylene random copolymer portion) in the propylene-ethylene block copolymer. (4) Cv: Content of the copolymerized portion (propylene-ethylene random copolymer portion) in the propylene-ethylene block copolymer. (5) Gv: Content of ethylene in the propylene-ethylene random copolymer portion. [2] Ethylene-propylene copolymer rubber EPR-1: [melt flow rate (MFR, 230 ° C, 2.16
kg load) 0.8 g / 10 min, hardness (JIS A) = 74] EPR-2: [Melt flow rate (MFR, 230 ° C, 2.16)
kg load) 4g / 10 minutes, hardness (JIS A) = 73] EPR-3: [Intrinsic viscosity [η] (decalin 135 ° C) 2.5
dl / g, propylene content 23% by weight] [3] Ethylene-butene copolymer rubber EBR-1: [melt index (MI, 190 ° C, 2.16
kg load) 3.5 g / 10 minutes, hardness (JIS A) = 85] EBR-2: [melt index (MI, 190 ° C, 2.16
kg load) 20 g / 10 minutes, hardness (JIS A) = 89] EBR-3: [Intrinsic viscosity [η] (decalin 135 ° C) 2.0
dl / g, butene-1 content 20% by weight] [4] Talc: [Fuji Talc Co., Ltd. LMS300, average particle size]
1.25 μm]

Examples 1 to 7 and Comparative Examples 1 to 9 Multi-stage polymerized propylene-ethylene block copolymers (BPP-1 to BPP-8) and ethylene-propylene copolymer rubber (EPR) at the compounding ratios shown in Table 2. -1, EPR-2 or EPR-3), ethylene-butene copolymer rubber (EBR-1, EBR-2 or EBR-3)
And talc were dry-blended with a super mixer, then charged into a twin-screw extruder and kneaded at 190 to 250 ° C. and a screw rotation speed of 200 rpm to obtain pellets.

Next, the obtained pellets were molded by an injection molding machine at an injection temperature of 210 ° C. and an injection pressure of 600 kg / cm ² into a test piece for measuring physical properties described later.

For the test piece thus obtained,
The ratio of the intrinsic viscosities of the propylene homopolymer portion and the other resin components in the composition was measured. The results are shown in Table 2. In addition, melt flow rate, tensile elongation at break, flexural modulus, Izod impact strength, heat deformation temperature, Rockwell hardness, embrittlement temperature, molding shrinkage and linear expansion were measured.
The results are shown in Table 3.

Table 2 Composition (parts by weight) Example 1 Example 2 Example 3 Example 4 Example 5 Type of BPP BPP-1 BPP-1 BPP-2 BPP-3 BPP-4 Compounding amount 47.2 50.6 50.6 54.6 52.8 EPR-1 12.5 13.4 13.4 13.7 15.5 EBR-1 10.3 11 11 11.7 11.7 Talc 30 25 25 20 20 Intrinsic viscosity ratio [η] _B / [η] _A ⁽¹⁾ 2.1 2.1 2.3 1.8 2.0

Table 2 (continued) Composition (parts by weight) Example 6 Example 7 Comparative Example 1 Comparative Example 2 Comparative Example 3 Types of BPP BPP-5 BPP-6 BPP-1 BPP-2 BPP-3 Blend Quantity 52.2 52.2 56.6 57.3 48 EPR-1 − − 21.1 6.7 12 EPR-2 16.1 16.1 − − − EBR-1 11.7 − 12.3 11.0 20 EBR-2- 11.7 − − − Talc 20 20 10 25 20 Intrinsic viscosity ratio [η] _B / [η] _A ⁽¹⁾ 1.4 1.5 ^{* * *} Note) *: Not measured.

Table 2 (continued) Composition (parts by weight) Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Types of BPP BPP-4 BPP-5 BPP-6 BPP-7 BPP -8 BPP-2 compounding amount 55.4 60.3 55.1 50.2 50.2 57.8 EPR-1 − − − − − − EPR-2 22.3 8 21 9.5 9.5 − EPR-3 − − − − − 13.3 EBR-1 12.3 11.7 − − − − EBR -2- − 3.9 10.3 10.3 − EBR-3 − − − − − 8.9 Talc 10 20 20 30 30 20 Intrinsic viscosity ratio [η] _B / [η] _A ^{(1) * * * * *} 2.9 Note) *: Measurement I didn't.

(1) Ratio of intrinsic viscosities of propylene homopolymer part and other resin components: 100% of the composition obtained by removing the inorganic filler (talc) from the cold xylene-insoluble part of the composition.
The ethylene homopolymer part was removed by heating to ℃, the remainder was made into the propylene homopolymer part, and the viscosity of the other resin components and the 135 ° C decalin solution was measured,
The ratio was calculated. The intrinsic viscosity of the propylene homopolymer portion was [η] _A , and the intrinsic viscosity of the other resin components was [η] _B.

Third physical property Example 1 Example 2 Example 3 Example 4 Example 5 M F R (g / 10 min) ⁽¹⁾ 14 15 16 16 16 Tensile elongation at break (%) ⁽²⁾ 90 110 110 120 110 Flexural modulus (kgf / cm ² ) ⁽³⁾ 21500 19700 19700 19200 19300 Izod impact strength (kgf-cm / cm, notched) ⁽⁴⁾ 23 ℃ 29 32 34 32 34 -30 ℃ 4.5 4.8 4.8 3.8 3.8 Heat distortion temperature (℃) ⁽⁵⁾ 132 130 130 130 129 Rockwell hardness (R) ⁽⁶⁾ 57 55 55 57 56 Embrittlement temperature (℃) ⁽⁷⁾ -8 -12 -14 -12 -16 Mold shrinkage ⁽⁸⁾ (× 1/1000) 3.8 4.3 4.4 5.5 5.4 Linear expansion ⁽⁹⁾ (× 10 ^-5 ℃ ^-1 ) 5.0 5.4 5.5 6.3 6.1

Table 3 (continued) Physical Properties Example 6 Example 7 Comparative Example 1 Comparative Example 2 Comparative Example 3 M FR (g / 10 min) ⁽¹⁾ 15 15 16 19 12 Tensile elongation at break (%) ) ⁽²⁾ 130 100 150 40 120 Flexural modulus (kgf / cm ² ) ⁽³⁾ 19000 19000 15900 21800 17500 Izod impact strength (kgf-cm / cm, notched) ⁽⁴⁾ 23 ℃ 26 29 36 25 36 − 30 ℃ 3.0 3.0 4.0 3.1 4.2 Heat distortion temperature (℃) ⁽⁵⁾ 128 128 123 132 115 Rockwell hardness (R) ⁽⁶⁾ 56 56 48 59 48 Embrittlement temperature (℃) ⁽⁷⁾ -15 -16 -15 -3-16 Molding shrinkage ⁽⁸⁾ (× 1/1000) 5.6 5.4 5.7 6.7 5.1 Linear expansion ⁽⁹⁾ (× 10 ^-5 ℃ ^-1 ) 6.4 6.2 6.3 6.3 5.8

Table 3 (continued) Physical Properties Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 M FR (g / 10 min) ⁽¹⁾ 17 18 16 19 15 13 Tensile Rupture Elongation (%) ⁽²⁾ 110 50 60 30 40 400 Flexural modulus (kgf / cm ² ) ⁽³⁾ 16000 19500 19500 22000 22000 19000 Izod impact strength (kgf-cm / cm, notched) ⁽⁴⁾ 23 ° C 34 24 26 29 34 31 −30 ℃ 3.0 2.8 2.8 3.0 3.0 3.8 Heat distortion temperature (℃) ⁽⁵⁾ 121 130 129 131 131 130 Rockwell hardness (R) ⁽⁶⁾ 50 57 49 54 53 56 Brittle temperature (℃ ) ⁽⁷⁾ −13 −2 −12 0 +4 −10 Molding shrinkage rate ⁽⁸⁾ (× 1/1000) 5.9 7.5 5.6 4.2 4.2 7.2 Linear expansion rate ⁽⁹⁾ (× 10 ⁻⁵ ℃ ⁻¹ ) 6.5 7.2 6.3 5.2 4.9 7.1

(1) MFR: 230 ° C., 216 according to ASTM D1238
Measured under 0 g load. (2) Tensile elongation at break: Measured according to ASTM D638. (3) Flexural modulus: measured by ASTM D790. (4) Izod impact strength: Measured with ASTM D256 using a 3.2 mm thick test piece with a notch. (5) Heat distortion temperature: Measured by ASTM D648 at a pressure of 4.6 kg / cm ² . (6) Rockwell hardness: measured by ASTM D785. (7) Brittle temperature: measured by ASTM D746. (8) Molding shrinkage ratio: 350 mm × 100 mm × 3 mm sheet was molded, and then left in a constant temperature room at 20 ° C. for 24 hours, and the shrinkage ratio was measured in the width direction (TD) and the longitudinal direction (MD), I took the average value. (9) Linear expansion coefficient: For a sheet similar to the molding contraction rate, −
Dimensional stability in the temperature range of 30 to 80 ° C
D) and the longitudinal direction (MD) were measured, and the average value was taken.

As is clear from Table 3, the resin composition for automobiles of the present invention has moldability (MFR value), tensile elongation at break, flexural modulus, Izod impact strength, heat distortion temperature, Rockwell hardness. The values of the embrittlement temperature, the molding shrinkage rate and the linear expansion coefficient were all at good levels, and the heat distortion resistance was particularly good. On the other hand, the compositions of the respective comparative examples have significantly deteriorated at least one of the above various physical properties.

Further, the paintability of the composition of each example was evaluated. The paintability is evaluated by washing the molded product with trichloroethane vapor, applying the primer and urethane-based top paint according to the standard paint specifications, and performing the primary adhesion (goggles test) and the hot water resistance test (40 ° C × 40 ° C). After 240 hours of immersion), a goggles test was performed to determine the adhesion and the presence or absence of blisters. The composition of the present invention had good coating performance such as adhesion of coating film and water resistance.

【The invention's effect】

As described in detail above, the resin composition for automobiles of the present invention comprises a multistage polymerized propylene-ethylene block copolymer, an ethylene-propylene copolymer type rubber,
In a composition containing ethylene-butene copolymer rubber and talc in predetermined amounts, respectively, as a multi-stage polymerized propylene-ethylene block copolymer, a propylene homopolymer portion, a propylene-ethylene random copolymer portion, It contains an ethylene homopolymer part in a specific ratio, the intrinsic viscosity of the propylene homopolymer part and the ethylene homopolymer part, the intrinsic viscosity of the propylene-ethylene random copolymer part, and the propylene-ethylene random copolymer part The ethylene content is used within a predetermined range, and since the ratio of the intrinsic viscosity of the propylene homopolymer portion in the composition and the other resin components is within a predetermined range, the paintability and moldability are improved. Excellent, impact resistance, ductility, mechanical strength, heat distortion resistance,
The embrittlement temperature and hardness are well balanced, and the molding shrinkage and linear expansion are small.

The composition of the present invention is suitable for interior and exterior materials of automobiles such as trims, side moldings, side garnishes and spoilers.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C08L 23:16 23:08) (72) Inventor Kunio Iwanami No.3 Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture No. 1 Tonen Kagaku Co., Ltd. Technology Development Center (72) Inventor Kichisho Kitano 3-1, Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Tonen Kagaku Co. Ltd. Technology Development Center (72) Inventor Hisayuki Iwai Toyota City, Aichi Prefecture Toyota Town No. 1 Toyota Motor Co., Ltd. (72) Inventor Takesumi Nishio No. 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Car No. 1 (72) Inventor Takao Nomura 1 Toyota Town, Aichi Prefecture Toyota Motor Vehicle Within the corporation

Claims (3)

[Claims] 1. A propylene-ethylene block copolymer obtained by multi-stage polymerization (40-60% by weight), and (b) an ethylene-propylene copolymer rubber (10-20% by weight).
And (c) ethylene-butene copolymer rubber 10 to 20% by weight, and (d) talc more than 15% by weight and 30% by weight or less,
A resin composition for automobiles, wherein the sum of (b) + (c) is 20 to 30% by weight, wherein the propylene-ethylene block copolymer is 4 to 10% by weight per 100% by weight of propylene. -Ethylene random copolymer part (
4.0 dl / g or more, the ethylene content in the propylene-ethylene random copolymer portion is 30 to 70% by weight) and the intrinsic viscosity is 0.9 to 1.2 dl / g containing a propylene homopolymer portion, and A motor vehicle characterized in that the ratio (A / B) of the intrinsic viscosity (A) of the propylene homopolymer portion and the intrinsic viscosity (B) of the resin component other than the propylene homopolymer portion is in the range of 0.1 to 2.5. Resin composition. 2. The automobile resin composition according to claim 1, wherein the talc has an average particle diameter of 1.5 μm or less. 3. The automotive resin composition according to claim 1 or 2, wherein the propylene-ethylene block copolymer has a melt flow rate of 40 to 120 g / 10 minutes. object.