JPH03252437A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition having excellent heat-resistance, impact resistance, scratch resistance and surface-peeling resistance and suitable as a bumper by compounding a propylene-ethylene block copolymer, an ethylene- propylene copolymer rubber, a rubber having high hardness, an amorphous nylon and a modified PP at specific ratios. CONSTITUTION:The objective composition contains (A) 50-89wt.% (preferably 55-75wt.%) of a propylene-ethylene block copolymer (preferably having a melt flow rate of 3-30g/10min), (B) 2-25wt.% (preferably 5-15wt.%) of an ethylene- propylene copolymer rubber (preferably having an ethylene content of 50-85% and a melt flow rate of 0.2-10g/10min), (C) 2-25wt.% (preferably 4-15wt.%) of a rubber having high hardness (e.g. ethylene-butene copolymer rubber), (D) 2-20wt.% (preferably 2.5-12.5wt.%) of an amorphous nylon (preferably having a Tg of 120-190 deg.C) and (E) 5-500 pts.wt., preferably 10-200 pts.wt. (based on 100 pts.wt. of the component D) of a modified PP.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermoplastic resin composition suitable for parts of automobiles, etc., which has particularly excellent heat resistance, impact resistance, scratch resistance, and surface peeling resistance. , relates to a thermoplastic resin composition suitable for bumpers.

[Prior Art and Problems to be Solved by the Invention] Polypropylene has been widely used in automobile parts since it is inexpensive and has excellent mechanical strength and other physical properties. This polypropylene has excellent heat resistance and rigidity, but has the disadvantage of poor impact resistance. Therefore, in order to improve the impact resistance of polypropylene, rubber-like substances such as polyisobutylene, polybutadiene, non-quality ethylene-propylene copolymer rubber (EPR), and polyethylene are generally mixed. However, the various materials mentioned above are softer and have lower softening points than polypropylene, so
There is a problem in that the inherent properties of polypropylene, such as rigidity and hardness, are reduced.

On the other hand, attempts have been made to improve the impact resistance of polyolefins by adding and mixing polyamides and the like to polyolefins such as polypropylene.

However, since polyolefin and polyamide are not compatible, there is a problem in that a mixture thereof has an extremely low mechanical strength.

Therefore, various proposals have been made to make polypropylene and polyamide compatible and to improve impact resistance to 1 without impairing the rigidity and hardness, which are the original characteristics of polypropylene.

JP-A-59-149940 discloses a propylene polymer (
A) 4 C1 to 98 parts by weight, polyamide (B) 60
to 2 parts by weight and <A) + (B) = 100
Ethylene-α with X-ray crystallinity O to 50% and ethylene content 40 to 93 mol% based on weight parts
- 1 to 50 parts by weight of an olefin copolymer (modified ethylene-olefin copolymer in which c000 parts by weight is graft-modified with 0.01 to 5 parts by weight of a graft monomer selected from unsaturated carboxylic acids or derivatives thereof)) Discloses a propylene polymer characterized by comprising:

However, in this propylene polymer, since the polyamide phase is not sufficiently finely and stably dispersed, there are problems in that surface peeling is likely to occur and the fluidity and gloss of the composition are reduced.

Further, JP-A-60-110740 discloses that propylene polymer (A) 95 to 5 parts by weight, polyamide ω) 5 to 9 parts by weight,
5 parts by weight and (A) + (B) = 100 parts by weight, a propylene-based olefin copolymer (01(10 A modified propylene lead olefin copolymer obtained by graft-modifying 0.01 to 5 parts by weight of a graft monomer selected from unsaturated carboxylic acids or derivatives thereof (D) to 80 parts by weight. A propylene polymer is disclosed.

This polymer has improved impact resistance, composition fluidity, and reduced gloss. However, the polyamide phase is still not sufficiently finely and stably dispersed, and there is a problem that surface peeling is likely to occur.

Furthermore, JP-A No. 63-61040 states that (a) <i)
hexamethylene diamine and/or hexamethylene diamine which may be alkyl-substituted, (ii) bis(4-amino-cyclohexyl)-methane homologues substituted at positions adjacent to the amino group, and (t)terephthalic acid; /
20 to 99.99% by weight of an amorphous copolyamide consisting of isophthalic acid, which may be substituted by other aromatic or aliphatic dicarboxylic acids, and 0.01 to 80% by weight of a modified copolyolefin. A thermoplastically deformable impact resistant polyamide alloy is disclosed.

However, this impact-resistant polyamide alloy has a relatively high embrittlement temperature, cannot exhibit sufficient impact resistance at low temperatures, and has insufficient mechanical strength such as flexural modulus.

Therefore, in view of the above-mentioned problems, the object of the present invention is to provide a polypropylene with good heat resistance, impact resistance, etc., sufficient surface hardness, finely and uniformly dispersed polyamide in polypropylene, and no surface peeling. An object of the present invention is to provide a thermoplastic resin composition.

[Means to solve the problem]

As a result of intensive research in view of the above problems, the present inventors have discovered that propylene-ethylene block copolymer, an appropriate amount of ethylene-propylene copolymer rubber (EPR), high hardness rubber,
A composition made by adding high-density polyethylene, amorphous nylon, and an appropriate amount of modified polypropylene to the amorphous nylon has fine amorphous nylon particles in the base resin matrix. It was discovered that it is uniformly dispersed, suppresses the peeling phenomenon at the interface with the resin matrix, and can thereby improve the impact resistance of the resin, while maintaining the heat resistance, hardness, etc. unique to polypropylene. , came up with the present invention.

That is, the thermoplastic resin composition of the present invention contains (a) 50 to 89% by weight of propylene-ethylene block copolymer, (b) 2 to 25% by weight of ethylene-propylene copolymer rubber, and (c) high Contains 2-25% by weight of hardness rubber, (6) 2-20% by weight of amorphous nylon, and (e) 5-500 parts by weight of modified polypropylene based on 100 parts by weight of the amorphous nylon. It is characterized by

The present invention will be explained in detail below.

The propylene-ethylene block copolymer (a) used in the present invention usually has an ethylene content of 3 to 20% by weight. If the ethylene content is less than 3% by weight, the impact resistance will be poor, and if it exceeds 20% by weight, the composition will have insufficient mechanical properties such as flexural modulus. The preferred ethylene content range is 4 to 15% by weight. Such a propylene-ethylene block copolymer can be obtained, for example, by first polymerizing propylene to form a polypropylene portion, then supplying ethylene for copolymerization, and repeating this operation once or twice or more.

In addition, the melt flow rate (MFR) of the propylene-ethylene block copolymer is 1 to 50 g/10 minutes (
230° C., 2.16 kg load).

If the VFR is less than Ig/10 minutes, flow marks etc. are likely to occur during molding and the surface appearance will deteriorate.

On the other hand, if the MFR exceeds 50 g/10 minutes, the impact resistance of the composition decreases. A more preferable range of MFH is 3 to 30 g.
/10 minutes.

The fE ratio of the above propylene-ethylene block copolymer is as follows: propylene-ethylene block copolymer + ethylene-propylene copolymer rubber (EPR) + high hardness rubber + high density polyethylene + amorphous polymer ((a )+(
b)+(c)+(d) (the same applies hereinafter) is taken as 100% by weight, from 50 to 89% by weight, preferably from 55 to 75% by weight. If the blending ratio of the propylene-ethylene copolymer is less than 50% by weight, the mechanical strength of the composition will be insufficient, and if it exceeds 89% by weight, impact resistance will decrease.

In the present invention, (b) ethylene-propylene copolymer rubber (EPR) is for improving impact resistance,
The ethylene content is 50 to 85% by weight, and the melt flow rate (230°C, 2.16 kg load) is 0.2 to 1
.

g710 minutes is preferable.

If the ethylene content in the ethylene-propylene copolymer rubber (BPR) is less than 50% by weight, the impact resistance of the composition will decrease, and if it exceeds 85% by weight, the heat deformation resistance of the composition will decrease. do. A more preferable range of ethylene content is 55 to 80% by weight.

Furthermore, if the melt flow rate of the ethylene-propylene copolymer rubber is less than 0.2 g/10 minutes, the moldability will decrease, and if it is greater than Log/10 minutes, the impact resistance of the composition will decrease. A more preferable melt flow rate range is 0.5 to 5 g/10 minutes.

The blending ratio of ethylene-propylene copolymer rubber (Japan PR) in the composition of the present invention is (a) + (b)
+ (c) + (company) as 100% by weight, 2 to 25
% by weight, preferably 5-15% by weight. Above EPR
If the blending ratio is less than 2% by weight, impact resistance will be insufficient. Moreover, if it exceeds 25% by weight, the surface appearance will be poor, which is not preferable.

In the present invention, (c) high hardness rubber is ethylene-
Butene copolymer rubber (EBR), styrene-ethylene
Butylene-styrene block copolymer (SEes>
, and histyrene-ethylene/propylene-styrene block copolymer (SBPS).

What is ethylene-butene copolymer rubber (BBR)?
The block copolymer has a butene-1 content of 10 to 40% by weight, and a block copolymer having a butene-1 content of 15 to 30% by weight is particularly preferable.

The melt flow rate (190°C, 2.16 kg load) of the above ethylene-butene copolymer rubber is 0.5 to 20 g.
710 minutes is preferred. In addition, in the present invention, ethylene-
The butene copolymer rubber is not limited to one consisting only of ethylene and butene, but one containing other resin components of about 10 mol % can also be used.

Styrene-ethylene/butylene-styrene block copolymer (SEBS) is a block copolymer in which a styrene part and an ethylene/butylene part form blocks, and the weight ratio of styrene/ethylene/butylene is 10.
/90 to 70 /30. If this ratio is less than 10/90, the strength will be insufficient, and if it exceeds 70/30, it will become brittle. The preferred styrene/ethylene/butylene weight ratio is 20/80 to 50,150. Also, styrene
The weight average molecular weight of the ethylene-butylene-styrene block copolymer is 10,000 to 1,000,000, and if it is less than 10,000, the mechanical strength is insufficient, and if it exceeds 1,000,000, the dispersion in the composition will deteriorate. . Note that the styrene portion is not limited to one consisting only of styrene, but may be one consisting of substituted styrene such as methylstyrene.

Styrene-ethylene/butylene-styrene block copolymers are disclosed in U.S. Pat.
It can be produced by the method described in No. 8.432. That is, by hydrogenating a styrene-butadiene-styrene triblock copolymer at a temperature of 25 to 175° C. in the presence of a catalyst prepared by reducing a cobalt or nickel alkoxide with an alkyl aluminum compound, the butadiene moiety is hydrogenated. is selectively hydrogenated, resulting in a structure corresponding to a copolymer of ethylene and butene-1. In addition, in the present invention, styrene-ethylene/butylene-
The styrene block copolymer is not limited to the above-mentioned method, but any method produced can be used.

Styrene-ethylene/propylene-styrene block copolymer (SEPS) is a block copolymer in which a styrene part and an ethylene/propylene part form a block, and the weight ratio of styrene/ethylene/propylene is 15/85 or more. It is 70/30. This is 15/
If it is less than 85, the mechanical strength is insufficient, and 70/30
It becomes brittle when it exceeds. The preferred weight ratio of styrene/ethylene/propylene is 20/80 to 50,150. In addition, the weight average molecular weight of the styrene-ethylene propylene-styrene block copolymer is 10,000 to 1,000,000. If it is less than 10,000, the mechanical strength is insufficient, and if it exceeds 1,000,000, the dispersibility in the composition is poor. Getting worse. Note that the styrene portion is not limited to one consisting only of styrene, but may be one consisting of substituted styrene such as methylstyrene.

Styrene-ethylene propylene-styrene block copolymers can generally be prepared by first forming a styrene-isoprene-styrene triblock copolymer and then hydrogenating the unsaturated bonds of the isoprene.

The styrene-isoprene block copolymer is preferably prepared under conventional anionic living polymerization conditions, and its hydrogenation is preferably carried out using a hydrogenation catalyst such as a nickel catalyst supported on diatomaceous earth. However, in the present invention, the present invention is not limited to this, and a ethylene/propylene/styrene block copolymer prepared by any other method may also be used.

The blending ratio of the above-mentioned high hardness rubber in the composition of the present invention is (a) + (b) + (c) + (d) 1
00% by weight, 2 to 25% by weight, preferably 4 to 1% by weight
It is 5% by weight.

If the blending ratio of the high hardness rubber is less than 2% by weight, the surface hardness and scratch resistance of the composition will not be sufficiently improved. Moreover, if it exceeds 25% by weight, the surface appearance will be poor, which is not preferable.

The Yamabe crystalline nylon used in the present invention includes:
For example, an amorphous polyamide disclosed in JP-A No. 63-61040 can be mentioned.

This amorphous nylon consists of (A) hexamethylene diamine and/or alkyl-substituted hexamethylene diamine, (B
) A bis(4-amino-cyclohexyl)-methane derivative having a substituent adjacent to the amino group, (0) isophthalic acid or other aromatic or aliphatic dicarboxylic acid, and (D) terephthalic acid in the following blending ratios. It is made by containing.

(A>Hexamethylenediamine and/or its alkyl-substituted derivative: 48-20 mol% ■) Bis(4-amino-cyclohexyl)-methane derivative = 2-30 mol% (c) Isophthalic acid or other aromatic or Aliphatic dicarboxylic acid:
50 to 40 mol% ■) Terephthalic acid: 0 to 10 mol% Among the above constituent substances, (A) alkyl-substituted derivatives of hexamethylene diamine include N, N'-dimethylhexamethylene diamine, N, N "-dibenzoylhexamethylene diamine and the like.

(B) Bis(4) substituted at the position adjacent to the amino group
-Amino-cyclohexyl)-methane derivatives include:
For example, bis(4-amino-3-methyl-5-ethylcyclohexyl)-methane, bis(4-amino-3,5-diethylcyclohexyl)-methane, bis(4-amino-
3-Methyl-5-isopropylcyclohexyl)-methane, bis(4-amino-3,5-diisopropylcyclohexyl)-methane, bis(4-amino-3,5-dimethylcyclohexyl)-methane, bis(4-amino- 3
-Methylcyclohexyl)-methane, bis(4-amino-3-ethylmethylcyclohexyl)-methane, bis(
Examples include alkyl-sensitive diamines such as 4-amino-3-isopropylcyclohexyl)-methane or mixtures thereof;
The - group may be substituted by ethylene, propylene, isopropylene or butylene.

(c) Examples of aromatic or aliphatic dicarboxylic acids other than isophthalic acid include aromatic dicarboxylic acids such as orthophthalic acid, aliphatic dicarboxylic acids such as sinuic acid, malonic acid, succinic acid, and dodecanedicarboxylic acid.

Furthermore, amorphous nylon as mentioned above has a glass transition point (T
g) is preferably 120 to 190°C.

The blending ratio of the amorphous nylon in the composition of the present invention is (a) + (b) + (c) + (d) 1
00% by weight, 2 to 20% by weight, preferably 2.5% by weight
~12.5% by weight. If the blending ratio of the above-mentioned amorphous nylon is less than 2% by weight, the effect of modifying polypropylene will be small, and no improvement in impact resistance will be observed;
If it exceeds this, it becomes difficult for the amorphous nylon to exist as a fine and uniform phase, and surface peeling is likely to occur.

Note that the smaller the dispersed particles of polyamide in the resin composition, the better the impact resistance. The average dispersed particle size of the polyamide is preferably 2 μm or less.

Furthermore, the (e) modified polypropylene used in the present invention is a polypropylene copolymerized with an unsaturated monomer having a carboxyl group or an epoxy group.

Examples of unsaturated monomers having a carboxyl group include unsaturated carboxylic acids or their anhydrides, such as monocarboxylic acids such as acrylic acid and methacrylic acid, dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid, and maleic anhydride. , itaconic anhydride, endic acid anhydride (himic anhydride), and other dicarboxylic acid anhydrides, with dicarboxylic acids and their anhydrides being particularly preferred. Examples of the unsaturated monomer having an epoxy group include glycidyl methacrylate and glycidyl acrylate.

Polypropylene modified with an unsaturated carboxylic acid or its anhydride, or polypropylene modified with an epoxy group, includes polypropylene homopoly, 7-
However, random or block copolymers with other α-olefins containing a propylene component of 50 mol % or more, preferably 80 mol % or more can also be used. Comonomers copolymerized with propylene include ethylene and other α-olefins, with ethylene being particularly preferred.

Note that polypropylene is not limited to homopolymers, but also includes copolymers.

The unsaturated carboxylic acid or its anhydride or the epoxy group-containing modified polypropylene may be a block copolymer, a graft copolymer, a random copolymer, or an alternating copolymer.

The content of unsaturated carboxylic acid or its anhydride in the modified polypropylene is preferably within the range of 0.01 to 10% by weight. Specifically, when modified with maleic anhydride, The content of maleic anhydride is 0.1 to 3% by weight, more preferably 0.2 to 2% by weight, and when using maleic anhydride, the content is 0.1 to 3% by weight. % by weight, preferably 0.2 to 2% by weight. If the amount of modification by maleic anhydride and himic anhydride is less than the above lower limit, the addition of modified polypropylene will not have a sufficient effect on improving the compatibility between amorphous nylon and polypropylene, and if it exceeds the upper limit, polypropylene The compatibility of is reduced.

The content of Epoquine groups in the modified polypropylene is 0.
The amount is preferably 0.01 to 10% by weight. If the content of Epoquine groups is less than 0.01% by weight, the addition of modified polypropylene will not have a sufficient effect on improving the compatibility between amorphous nylon and polypropylene, and if it exceeds 10% by weight, the compatibility with polypropylene will increase. decreases.

The melt flow rate of the modified polypropylene as described above is within the range of 1 to 1000 g/10 minutes.

Modified polypropylene can be produced by either a solution method or a melt-kneading method. In the case of the melt mixing method, a polyolefin, an unsaturated carboxylic acid (or acid anhydride) for modification, an unsaturated monomer having an epoxy group, and a catalyst are charged into an extruder or twin-screw kneader, and heated to a temperature of 150 to 250°C. Knead while heating and melting. In addition, in the case of the solution method,
Dissolve the above starting material in an organic solvent such as xylene, and
It is carried out at a temperature of 140° C. with stirring. In either case, ordinary radical polymerization catalysts can be used as catalysts, such as benzoyl peroxide, lauroyl peroxide, di-tert-butyl peroxide, acetyl peroxide, tert-butyl peroxybenzoic acid, dicumyl peroxide, Peroxides such as peroxybenzoic acid, peroxyacetic acid, tert-butylperoxypivalate, 2,5-dimethyl-2,5-ditertiary-butylperoxyhexine, and diazo compounds such as azobisisobutyroni) etc. are preferred. The amount of the catalyst added is about 1 to 100 parts by weight per 100 parts by weight of the modifying unsaturated carboxylic acid or its anhydride or epoxy group.

In the resin composition of the present invention, the content of modified polypropylene is 5 to 5 parts by weight based on 100 parts by weight of amorphous nylon.
00 parts by weight, preferably 10 to 200 parts by weight. If the content of the modified polypropylene is less than 5 parts by weight, the compatibility between the polypropylene and the amorphous nylon will not improve, and the peeling phenomenon between them cannot be suppressed. Moreover, if it exceeds 500 parts by weight, mechanical strength and weather resistance will decrease.

In addition to the above-mentioned components (a) to (e), the thermoplastic resin composition of the present invention contains (f) high-density polyethylene for the purpose of further improving the rigidity, hardness, and impact resistance of the composition. May contain. In the present invention, the high density polyethylene preferably has a density of 0.93 to 0.97 g/ci and a melt index (old) (190° C., 2.16 kg load) of 1 to 30 g/10 min. If the MI of high-density polyethylene is less than Ig/10 minutes, moldability is poor and flow marks are likely to occur. Also MI is 30g
If the time is longer than /10 minutes, the impact resistance of the composition at low temperatures will decrease. A more preferable MI range is 1 to 15 g/
It's 10 minutes.

The blending ratio of high density polyethylene in the composition of the present invention is (a) + (b) + (c) + (d) +
The content of (f) is 25% by weight or less, preferably 10 to 20% by weight, based on 100% by weight. If the blending ratio of the high-density polyethylene is more than 25% by weight, the surface properties of the molded product will deteriorate.

In addition, when the thermoplastic resin composition of the present invention contains high-density polyethylene, the content 1 of the above-mentioned (a) to (e) is such that (a) the propylene-ethylene block copolymer is 50 to 50%
89% by weight, ethylene-propylene copolymer rubber (
εPR) is 2 to 25% by weight, and (c) high hardness rubber is 2 to 2% by weight.
5% by weight, (d) 2 to 20% by weight of amorphous nylon, (
e) It is preferable that the amount of modified polypropylene is 5 to 500 parts by weight based on 100 parts by weight of the amorphous nylon.

In particular, [a) 55 to 75% by weight of propylene-ethylene block copolymer, (b) 5 to 15% by weight of ethylene-propylene copolymer rubber (εPR), and (c) 4 to 15% by weight of high hardness rubber. %, (6) amorphous nylon is 2.5 to 1
2.5% by weight, (e) modified polypropylene 10-20%
Preferably, it is 0 parts by weight.

The thermoplastic resin composition of the present invention has the above composition, but inorganic fillers, carbon black, etc. may be added to improve mechanical strength, heat resistance, etc. At this time, it is preferable that the blending ratio of the resin composition of the present invention is 50% or more in terms of volume ratio at 23°C. When the content of additives such as inorganic fillers and carbon black exceeds 50% by volume, moldability decreases, making it difficult to manufacture molded products, and the mechanical strength also decreases.

The resin composition of the present invention may also contain other additives for the purpose of modification, such as heat stabilizers, light stabilizers, flame retardants, plasticizers, antistatic agents, mold release agents, blowing agents, and nucleating agents. etc. can be added.

The thermoplastic resin composition of the present invention can be produced by mixing the components described above and dynamically heat-treating, that is, melt-kneading. As the kneading device, conventionally known ones can be used, such as an open type mixing roll, a closed type Banbury mixer 1 extruder (including twin screws), and a kneader 1 continuous mixer. Kneading at 180-280℃
at a temperature of 200 to 250 °C, preferably 200 to 250 °C.
It may be carried out for 5 to 10 minutes, preferably 1 to 5 minutes.

[For production]

The thermoplastic resin composition of the present invention comprises (a) 50 to 89% by weight of propylene-ethylene block copolymer, (b) 2 to 25% by weight of ethylene-propylene copolymer rubber, and (c)
) 2 to 25% by weight of high hardness rubber, (d) 2 to 20% by weight of amorphous nylon, and (e) 5 to 500 parts by weight of modified polypropylene based on 100 parts by weight of the amorphous nylon. Because of this, it has a good balance of heat resistance, impact resistance, scratch resistance, etc., has high surface hardness, and does not cause surface peeling.

The reason why such an effect is obtained is not necessarily clear, but by blending each of the above components in the above range, amorphous nylon has a fine average particle size (2 This is thought to be due to the uniform distribution of the particles.

〔Example〕

The present invention will be explained in more detail by the following specific examples.

In each of the Examples and Comparative Examples, the following resins were used as raw material resins.

[1] Polypropylene BPP: Propylene-ethylene block copolymer [melt flow rate (MFR, 230°C, 2.16 kg
Load) 9g/10 minutes, ethylene content 5% by weight] [21 Ethylene-propylene copolymer rubber EPR: [Melt flow rate (MFR, 230°C, 2.16kg
load) 0.7 g/10 min, propylene content 27% by weight] [3] High hardness rubber ■ Ethylene-butene copolymer EBR: [Melt flow rate (MFR, 190°C,
2.16kg load) 3.5g/10 minutes, 1-butene content 20% by weight, density 0.88g/cm] Styrene-ethylene butylene-styrene block copolymer 5EBS:C melt flow rate (MFR, 230t
, 2.16 kg load) 3.4 g/10 min, styrene content 30% by weight, density 0.91 g/cnf] ■ Styrene-ethylene propylene-styrene block copolymer (I) SEPS (I): C melt Flow rate (MFR, 2
00℃, 10kg load) Ig/10 minutes, styrene content 15% by weight] ■Styrene-ethylene/propylene-styrene block copolymer 5EPS■: [Melt Flowray) (MF [l
, 200°C, lokg load > 0.1/10 min, styrene content 50% by weight] [4] Amorphous nylon^mNy: (melt viscosity 1450Pa -S (270t
, 12.6 kg load), Tg 142 °C [5] Modified polypropylene CMPP: (Melt flow rate (MFR, 230t,
2.16 kg load) 80 g/10 min, maleic anhydride content 0.3% by weight] [6 high density polyethylene HDPE: [melt index (Ml, 190 °C,
2.16kg load) 5g/10 minutes, density 0.958g/
c++f] Examples 1 to 6 and Comparative Examples 1 to 8 Propylene-ethylene block copolymer shown in Table 1, ethylene-propylene copolymer rubber (EPR>), high hardness rubber, amorphous nylon, Modified polypropylene and high-density polyethylene were mixed in a two-axis directional kneader (45 mm
φ, L/D 28), and melt-kneaded at 210° C., 20 rpm, and a discharge rate of 39 kg/hr to form a melt (L/−).

Next, the obtained pellet was molded into test pieces for measuring various physical properties as described later using an 8-ounce injection molding machine manufactured by Toshiba ■ at an injection temperature of 210°C.

Flexural modulus, thermal deformation temperature, Rockwell hardness, Izod impact strength, and embrittlement temperature were measured for these test pieces.

The results are shown in Table 1.

For comparison, a composition that did not contain at least one of high-density polyethylene, high-hardness rubber, and ethylene-propylene copolymer rubber and a composition that contained too much high-hardness rubber were pelletized in the same manner, and then various It was molded into a test piece for measuring physical properties. The flexural modulus, thermal deformation temperature, Rockwell hardness, Izod impact strength, and embrittlement temperature were measured on these test pieces in the same manner as in Example 1.

The results are also shown in Table 1.

(1) Measured in accordance with JS K7203.

(2) Measured in accordance with JS K7207.

(3) Measured in accordance with JS K7202.

(4) Measured in accordance with JS K7110.

(5) Measured in accordance with Js K7216.

As is clear from Table 1, the thermoplastic resin composition of the present invention had good flexural modulus, thermal distortion temperature, Rockwell hardness, and Izod impact strength, and also had a sufficiently low embrittlement temperature. On the other hand, the composition of Comparative Example 1, which did not contain high hardness rubber, had a small Rockwell hardness.
The compositions of Comparative Examples 2 to 7 have low Izot impact strength values, and the composition of Comparative Example 8, which contains too much high hardness rubber, has low values of flexural modulus, heat distortion temperature, and Rockwell hardness. It was low.

〔Effect of the invention〕

As detailed above, the thermoplastic resin composition of the present invention has excellent mechanical properties such as heat resistance and impact resistance, and has sufficient surface hardness, so it has good scratch resistance. It is.

Since the composition of the present invention as described in item 2 has the above-mentioned properties, it is suitable for automobile parts, particularly for automotive parts.

applicant representative person Tonen Petrochemical Co., Ltd. Toyota Motor Corporation

Claims (9)

[Claims] (1) (a) Propylene-ethylene block copolymer 5
(b) 2-25% by weight of ethylene-propylene copolymer rubber; (c) 2-25% by weight of high-hardness rubber; (d) 2-20% by weight of amorphous nylon. , (e) 5 to 100 parts by weight of the amorphous nylon
A thermoplastic resin composition comprising 500 parts by weight of modified polypropylene. (2) In the thermoplastic resin composition according to claim 1,
The thermoplastic resin composition contains 25% of high density polyethylene.
1. A thermoplastic resin composition, characterized in that it contains not more than % by weight. (3) The thermoplastic resin composition according to claim 1 or 2, wherein the propylene-ethylene block copolymer contains 3 to 20% by weight of ethylene. (4) The thermoplastic resin composition according to any one of claims 1 to 3, wherein the modified polypropylene is polypropylene modified with an unsaturated carboxylic acid or an anhydride thereof. thing. (5) The thermoplastic resin composition according to any one of claims 1 to 4, wherein the modified polypropylene has a melt flow rate of 1 to 1000 g/10 minutes. (6) The thermoplastic resin composition according to any one of claims 1 to 5, wherein the propylene-ethylene block copolymer has a melt flow rate of 1 to 50 g/10 minutes. Composition. (7) The thermoplastic resin composition according to any one of claims 1 to 7, wherein the ethylene content of the ethylene-propylene copolymer rubber is 50 to 85% by weight, and the melt flow rate is 0.2 to 85% by weight. A thermoplastic resin composition characterized in that the yield is 10 g/10 minutes. (8) The thermoplastic resin composition according to any one of claims 1 to 7, wherein the high-density polyethylene has a melt index of 1 to 30 g/10 minutes and a density of 0.93.
A thermoplastic resin composition characterized in that it has a weight of 0.97 g/cm^3. (9) The thermoplastic resin composition according to any one of claims 1 to 8, wherein the amorphous nylon has a glass transition point of 120 to 190°C.