JPH09157491A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition excellent in mechanical strength such as shock resistance, hardness, rigidity, moldability, heat resistance and resistance to metallic hazard. SOLUTION: This resin composition comprises 100 pts.wt. of the resin components with a melt flow rate(MFR) of 15-40g/10min and containing (A) 50-75 pts.wt. of a propylene-ethylene block copolymer containing (i) 5-20wt.% of a polypropylene-ethylene copolymer (having an intrinsic viscosity of 3-5dl/g and an ethylene content of 30-50wt.% in the copolymerization part) (ii) 95-80wt.% of a propylene homopolymer satisfying the formula: ΔHm >=24.5+1.583log MFR where ΔHm is the heat of fusion, (B) 25-50 pts.wt. of talc with an average particle size of <=5μm, (C) 0.01-2 pts.wt. per 100 pts.wt. of the resin components (A and B), of an antioxidant and (D) 0.01-2 pts.wt. of a metal deactivator.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition, and particularly to mechanical strength such as impact resistance, hardness and rigidity,
The present invention relates to a thermoplastic resin composition having excellent moldability, heat resistance, metal damage resistance and the like.

[0002]

BACKGROUND OF THE INVENTION Polypropylene is widely used in various fields because it is lightweight and has excellent mechanical strength and the like. However, since it is inferior in impact resistance, various rubbers such as an ethylene-propylene copolymer rubber (EPR) and an inorganic filler such as talc are added to a propylene-ethylene block copolymer for the purpose of improving the impact resistance. A polypropylene resin composition has been proposed.

Japanese Unexamined Patent Publication (Kokai) No. 1-149845 discloses that (a) a boiling xylene-soluble component having an ethylene content of 20 to 60% by weight.
~ 12% by weight, the total ethylene content of the polymer is 1 to 7
% By weight and melt flow rate of 15 to 50 g / 10
Minutes propylene-ethylene block copolymer 59-74
% By weight, and (b) the propylene content is 20 to 60% by weight, and the Mooney viscosity ML _{1 + 4} (100 ° C.) is 100 to 150.
35% to 20% by weight of ethylene-propylene copolymer rubber, and (c) 3 to 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. Disclosed is a resin composition characterized by the following.

This resin composition contains fine talc having an average particle size of 1.0 μm or less as talc.
Fine talc easily forms agglomerates, and when agglomerates are formed, the balance of mechanical strength such as hardness, rigidity, and impact resistance at low temperature becomes poor. Further, when the specific surface area of talc is increased by using fine talc, the talc trapping effect (adsorptivity) is enhanced, and therefore, there is a problem that talc adsorbs various additives. Therefore, it has been attempted to improve the dispersibility of fine talc and suppress the adsorption of additives by subjecting talc to a surface treatment with an aminosilane-based treatment agent or a titanate-based treatment agent. However, there is a problem that it does not have a sufficient effect.

When polypropylene resin is used for automobile parts such as fan shroud, timing belt cover and heater case, heat resistance is required in addition to mechanical strength such as impact resistance. For this reason, a method of adding glass fibers is known, but the mold releasability of the molded product from the mold and the surface smoothness are deteriorated, and it is disadvantageous in terms of cost and recyclability. For example, the glass fiber in the polypropylene-based resin composition molded by re-kneading the polypropylene-based resin composition to which the glass fiber is added is easily broken in the manufacturing process, and sufficient mechanical strength cannot be obtained.

Further, in recent years, in order to cope with the improvement of production efficiency and the increase in size and thickness of molded products, it is desired that the resin material has high fluidity and excellent moldability.

Accordingly, the object of the present invention is to provide impact resistance,
It is an object of the present invention to provide a thermoplastic resin composition having excellent mechanical strength such as hardness and rigidity, moldability, heat resistance, and metal damage resistance.

[0008]

Means for Solving the Problems As a result of intensive studies in view of the above objects, the proportion and intrinsic viscosity of the propylene-ethylene copolymerized portion and the ethylene content of the propylene-ethylene copolymerized portion are within a predetermined range, and To produce a propylene-ethylene block copolymer, and to add talc, an antioxidant and a metal deactivator to it so that a predetermined relationship is established between the heat of fusion of the propylene homopolymer part and the melt flow rate. It was found that the thermoplastic resin composition excellent in mechanical strength such as impact resistance, hardness and rigidity, moldability, heat resistance, metal damage resistance and the like can be obtained, and the present invention was conceived.

That is, the thermoplastic resin composition of the present invention has (a) a melt flow rate (MFR) of 15 to 40 g / 10 minutes, and (i) a propylene-ethylene copolymerized portion (having an intrinsic viscosity of 3). At 5 dl / g, the ethylene content of the copolymerized portion is 30 to 50% by weight.) 5 to 20% by weight, and (ii) the heat of fusion (ΔH _m ) and MFR are ΔH _m
Propylene-ethylene block copolymer 50 to 7 containing 95 to 80% by weight of a propylene homopolymer portion satisfying the relational expression ≧ 24.5 + 1.583 log MFR.
(C) 0.01 to 2 parts by weight of an antioxidant, and (d) metal And 0.01 to 2 parts by weight of an inactivating agent.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below. [1] Each component of the thermoplastic resin composition (1) Resin component (a) Propylene-ethylene block copolymer The propylene-ethylene block copolymer used in the present invention is preferably one synthesized by multistage polymerization.

In the multi-stage polymerization, propylene is first polymerized in the presence of a Ziegler catalyst or the like to form a crystalline propylene homopolymer part (which may contain a small amount of comonomer component), and ethylene + Switching to propylene produces a propylene-ethylene copolymerization moiety.

The propylene-ethylene block copolymer synthesized by the above multistage polymerization is substantially composed of a crystalline homopolypropylene portion, a propylene-ethylene copolymer portion and a small amount of a crystalline homopolyethylene portion. , Each part may exist as a single polymer, or each part may be in a bonded state. The above parts are basically composed of propylene and / or ethylene, but other α-
It may contain a small amount of an olefin or a diene monomer.

With respect to the content of each of the above parts, the crystalline homopolypropylene part is 80 to 95% by weight, preferably 85 to 90% by weight, with the sum of + being 100% by weight.
And the propylene-ethylene copolymerization portion is 5 to 20% by weight, preferably 10 to 15% by weight. Even if it contains a crystalline homopolyethylene portion, its content is 3% by weight or less. When the propylene-ethylene copolymerized portion is less than 5% by weight (when the crystalline homopolypropylene portion exceeds 95% by weight), the effect of improving mechanical strength and the like cannot be seen. On the other hand, when the propylene-ethylene copolymerized portion exceeds 20% by weight (when the crystalline homopolypropylene portion is less than 80% by weight), the rigidity and impact resistance decrease. The content of the propylene-ethylene copolymerized portion is determined by measuring the proportion of the soluble portion in cold xylene.

Regarding the above-mentioned crystalline homopolymer part,
It is necessary that the heat of fusion (ΔH _m ) and the MFR satisfy the relational expression ΔH _m ≧ 24.5 + 1.583 log MFR. ΔH _m <24.
In the case of 5 + 1.583 log MFR, rigidity and heat resistance are low.

The content of ethylene in the propylene-ethylene copolymerized portion is 30 to 50% by weight, preferably 35 to 50% by weight.
50% by weight. If the ethylene content is less than 30% by weight or exceeds 50% by weight, the ductility is particularly insufficient.
The intrinsic viscosity [η] of the propylene-ethylene copolymerized portion is 3
-5 dl / g, preferably 4-5 dl / g. When the intrinsic viscosity [η] is less than 3 dl / g, the effect of improving the impact resistance is insufficient, while when it exceeds 5 dl / g, the rigidity and the impact resistance decrease.

The MFR of such a propylene-ethylene block copolymer is 15 to 40 g / 10 minutes, preferably 20 to 40 g / 10 minutes. MFR value is 15g / 1
If it is less than 0 minutes, the moldability of the obtained composition, particularly injection moldability, will be lowered, and if it exceeds 40 g / 10 minutes, the mechanical strength will be lowered.

(B) Talc The talc used in the present invention has an average particle size of 5 μm or less, preferably 1 to 5 μm as measured by a laser diffraction / scattering method. If the average particle size of talc exceeds 5 μm, the specific surface area cannot be sufficiently increased, and the rigidity and impact resistance of the composition decrease.

From the viewpoint of improving mechanical strength, heat resistance and weather resistance, it is preferable to use talc surface-treated with modified silicone. As the modified silicone for treating talc, a modified silicone obtained by adding a silazane compound to an organopolysiloxane (typically, polydimethylsiloxane or the like) is preferable. Examples of the silazane compound include silazane, disilazane, trisilazane, hexacyclosilazane and the like. The addition amount of the silazane compound is 1 for the whole modified silicone.
The amount of 00% by weight is preferably 0.1 to 5% by weight, particularly preferably 1 to 3% by weight.

The surface treatment of talc with the above modified silicone is carried out by blending 0.1 to 5 parts by weight, especially 0.2 to 1 part by weight of modified silicone with 100 parts by weight of talc and mechanically using a Henschel mixer or the like. It can be performed by mixing.

Although the reason why such an effect is obtained is not always clear, the surface of talc is treated with a modified silicone such as a silazane compound to prepare a resin component (propylene-ethylene block copolymer alone or ethylene-propylene block copolymer). It is considered that this is because the dispersibility of talc in the copolymer rubber and the ethylene-butene copolymer rubber) is improved and the adsorbability of various additives to talc is significantly reduced.

(C) Other components In addition to the above-mentioned propylene-ethylene block copolymer and talc, an ethylene-propylene copolymer rubber and an ethylene-butene copolymer rubber can be added. By using these copolymer rubbers together, impact resistance and the like can be further improved. The MFR of the ethylene-propylene copolymer rubber (EPR) is 0.5 to 20 g / 10.
Minutes are preferable, and 3 to 20 g / 10 minutes are more preferable. M
When FR is less than 0.5 g / 10 minutes, moldability is lowered, and when FR exceeds 20 g / 10 minutes, mechanical strength is lowered. Further, from the viewpoint of handling property, productivity, etc., the content of ethylene is 50 to 90 mol%, the content of propylene is 50.
It is preferably from 10 to 10 mol%.

Ethylene-butene copolymer rubber (EBR)
The MFR of 0.2 to 30 g / 10 min is preferable, and the MFR of 0.
It is more preferably 5 to 10 g / 10 minutes. MFR is 0.2g
If it is less than / 10 minutes, the moldability is lowered, while 30 g /
If it exceeds 10 minutes, the mechanical strength will decrease. Further, from the viewpoint of handling property, productivity, etc., the ethylene content is 70-
Those having a content of 90 mol% and a butene-1 content of 30 to 10 mol% are preferable. The ethylene-butene copolymer rubber contains, in addition to ethylene and butene-1, a small amount of other α-olefins such as hexene-1 and octene-1 and diene compounds such as ethylidene norbornene and dicyclopentadiene. Good.

(D) Blending Ratio of Resin Component The blending ratio of the resin component is 50 to 75 parts by weight, preferably 60 parts by weight of the propylene-ethylene block copolymer.
To 70 parts by weight, talc is 50 to 25 parts by weight, preferably 40 to 30 parts by weight. If the blending amount of the propylene-ethylene block copolymer is less than 50 parts by weight (the blending amount of talc exceeds 50 parts by weight), the impact resistance is low, while if it exceeds 75 parts by weight (the blending amount of talc is 25
If it is less than 1 part by weight), the rigidity and heat resistance are deteriorated.

When the ethylene-propylene copolymer rubber and the ethylene-butene copolymer rubber are blended, the propylene-ethylene block copolymer is 35 to 72.5 parts by weight, and the ethylene-propylene copolymer rubber and The ethylene-butene copolymer rubber is preferably 2.5 to 15 parts by weight and the talc is preferably 25 to 50 parts by weight. The weight ratio of the ethylene-propylene copolymer rubber and the ethylene-butene copolymer rubber is preferably 1/99 to 99/1. A more preferred range is 46 to 67 parts by weight of propylene-ethylene block copolymer, 3 to 14 parts by weight of ethylene-propylene copolymer rubber and ethylene-butene copolymer rubber, and 30 to 4 of talc.
0 parts by weight.

(2) Additives The additives used in the present invention are an antioxidant and a metal deactivator.

(A) Antioxidant The antioxidant used in the present invention is a phenol-based, phosphorus-based and / or sulfur-based antioxidant, which acts as a heat stabilizer. As a phenolic antioxidant,
Pentaerythrityl-tetrakis- [methylene-3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate], 3,9-bis {2- [3- (3-t
-Butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,
4,8,10-tetraoxapyro [5,5] undecane, 1,3,5-tris (2,6-dimethyl-3-hydroxy-4-t-butylbenzyl) isocyanurate,
1,3,5-Tris (3,5-di-t-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, 1,3,5-tris (3,5-di-t-butyl) -4
-Hydroxybenzyl) isocyanurate, bis (3,3
Examples thereof include ethyl 5-di-t-butyl-4-hydroxybenzylphosphonate). Among commercially available phenolic antioxidants, the trade name is “IRGANOX 10”.
10 "and" Irganox 3114 "(manufactured by Ciba Geigy) and the like are preferable.

Examples of the phosphorus-based antioxidants include phosphorus-based stabilizers such as alkyl phosphite, alkylallyl phosphite, allyl phosphite, alkyl phosphonite, and allyl phosphonite. (2,4-di-t-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, tetrakis (2,4-di-t-butylphenyl)-
4,4'-biphenylene phosphonite, bis (2,4
-Di-t-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-diphosphite,
Examples thereof include 1,1,3-tris (2-methyl-4-ditridecylphosphite-5-t-butylphenyl) butane.

As the sulfur type antioxidant, distearyl-3,3'-thiodipropionate, pentaerythritol-tetrakis (3-laurylthiopropionate), dilauryl-3,3'-thiodipropionate. ,
Examples thereof include dimyristyl-3,3'-thiodipropionate, ditridecyl-3,3'-thiodipropionate, and dilauryl thiodipropionate.

Among these antioxidants, pentaerythrityl-tetrakis- [methylene-3- (3,5-di-
t-butyl-4-hydroxyphenyl) propionate], tris (2,4-di-t-butylphenyl) phosphite, distearyl-3,3'-thiodipropionate, pentaerythritol-tetrakis (3-lauryl) Thiopropionate) and dilauryl-3,3'-thiodipropionate are preferred. These can be used alone or in combination of two or more.

The blending amount of the above-mentioned antioxidant is the resin component 1
It is 0.01 to 2 parts by weight, preferably 0.03 to 1 part by weight, relative to 00 parts by weight. The antioxidant content is 0.
If it is less than 01 parts by weight, the antioxidant effect is not sufficient, and 2
Even if it exceeds the weight part, the improvement of the corresponding effect is not seen.

(B) Metal Deactivator The metal deactivator used in the present invention has, for example, resistance to copper damage, and is decamethylenedicarboxylic acid disalicyloyl hydrazide, 2,2′-oxamide-bis. -[Ethyl-
3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N'-bis [3- (3,5-
Di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and the like. Among these, N,
N'-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine is preferred.

The amount of the metal deactivator blended is 0.01 to 2 parts by weight, preferably 0.05 to 1 part by weight, based on 100 parts by weight of the resin component. If the compounding amount of the metal deactivator is less than 0.01 part by weight, the metal damage resistance is not sufficient,
Further, even if the amount exceeds 2 parts by weight, the corresponding effect is not improved.

[2] Other Components In addition to the thermoplastic resin composition of the present invention, other additives such as a nucleating agent, a flame retardant, a plasticizer, an antistatic agent, and a release agent may be added for the purpose of modifying the thermoplastic resin composition. Agents, foaming agents, coloring agents, pigments and the like can be added.

[3] Method for producing thermoplastic resin composition In the thermoplastic resin composition of the present invention, the above components are mixed using a Henschel mixer, a super mixer, a ribbon blender, etc., and a single screw extruder, a twin screw extruder, It can be obtained by melt-kneading in a temperature range of 180 to 300 ° C. with a Banbury mixer, a kneader or the like. Further, a masterbatch in which talc, an antioxidant, a heat stabilizer, a metal deactivator and other additives are added at a high concentration may be prepared in advance and blended in a propylene-ethylene block copolymer or the like.

[0035]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. Examples 1-7 and Comparative Examples 1-6 1. Raw material (1) Propylene-ethylene block copolymer (BPP) Properties of BPP BPP1 BPP2 BPP3 BPP4 BPP5 MFR (g / 10min) 34 30 20 27 30 Copolymerized portion ⁽¹⁾ ratio (% by weight) ⁽²⁾ 11 12 10 15 21 ethylene content (wt%) 42 50 40 38 50 intrinsic viscosity (dl / g) 5 3 3.5 4.5 7 homopolypropylene moiety heat of fusion (cal / g) measured value ^{_{(△ H m) (3)}} 27.0 26.5 26.8 28.1 28.0 Calculated value (△ H _m ′) ⁽⁴⁾ 26.9 26.8 26.6 26.8 26.8 Note (1): Ethylene-propylene copolymer part (2): Propylene-ethylene copolymer part and crystalline homopolypropylene part It is the content of the propylene-ethylene copolymerized portion when it is 100% by weight, and refers to the proportion of the cold xylene-soluble portion. (3): Measured by DSC (manufactured by Perkin Elma) (temperature rising rate: 20 ° C / min). (4): Calculated by ΔH _m ′ = 24.5 + 1.583log MFR.

(2) Propylene homopolymer (HPP) -MFR (g / 10min): 40-Heat of fusion (cal / g) Measured value (ΔH _m ): 29.1 Calculated value (ΔH _m ′): 27.0

[0037] (3) Talc Talc Average particle size ^{(μm) (1) Ta-} 1 3.6 Ta-2 4.2 Ta-3 5.0 Ta-4 12.0 Ta-5 (2) 3.6 Note (1): by a laser diffraction scattering method Measurement. (2): Surface-treated talc obtained by masterbatching 100 parts by weight of talc with 1 part by weight of silazane-modified polysiloxane and crystalline homopolypropylene (MFR = 40 g / 10 min) in a weight ratio of 3: 1.

(4) Additives ・ Ph-AO: Phenol type antioxidant (Irganox 10
10, Ciba Geigy) ・ P-AO: Phosphorus antioxidant (Mark2112, Asahi Denka Co., Ltd.) ・ MD: Metal deactivator (MD1024, Ciba Geigy)

2. Kneading and molding method The above raw materials were blended in the proportions shown in Table 1, dry-blended using a super mixer, and then a twin-screw extruder (PCM-45 manufactured by Ikegai Corp.) at 230 ° C. and 200 rp.
The mixture was melt-kneaded at a screw rotation speed of m and extruded to obtain pellets. The obtained pellets were injection-molded by an injection molding machine at a resin temperature of 230 ° C., an injection pressure of 750 kg / cm ² and a mold temperature of 50 ° C. to prepare test pieces.

3. Physical property measurement Physical property measurement of each test piece was performed by the following methods. The results are shown in Table 1 below. (1) MFR (g / 10 minutes): Measured according to ASTM D1238 at 230 ° C and a load of 2.16 kg. (2) Tensile strength (kg / cm ² ): Measured at room temperature according to ASTM D638. (3) Tensile elongation at break (%): Measured at room temperature according to ASTM D638. (4) Flexural modulus (kg / cm ² ): Measured at room temperature according to ASTM D790. (5) Flexural strength (kg / cm ² ): Measured at room temperature according to ASTM D790. (6) Izod impact strength (kgcm / cm): Measured at 23 ° C with a notch using a 3.2 mm thick test piece according to ASTM D256. (7) Heat distortion temperature (℃): 18.6kg / cm ^{2 according} to ASTM D648
The pressure was measured. (8) Rockwell hardness (scale R): Measured by ASTM D785. (9) Copper damage resistance: A test piece sandwiched between two thin copper plates and fixed with a clip was held in a gear oven at 150 ° C for 1000 hours, and examined for changes in appearance (discoloration and cracks) (○ ・・
・ No change was observed at all, × ... Change was observed).

Table 1 Example 1 Example 2 Example 3 Example 4 Composition Resin component BPP or HPP type BPP1 BPP3 BPP4 BPP1 Compounding amount (wt%) 70 70 70 70 Talc type Ta-3 Ta-3 Ta-3 Ta -5 Compounding amount (wt%) 30 30 30 30 Additive (parts by weight) Ph-AO 0.1 0.1 0.1 0.1 P-AO 0.1 0.1 0.1 0.1 MD 0.3 0.3 0.3 0.3 Characteristic of composition MFR (g / 10min) 33 15 25 36 Tensile strength (kg / cm ² ) 310 310 285 350 Tensile elongation at break (%) 30 30 50 80 Flexural modulus (kg / cm ² ) 32100 32000 31000 34000 Bending strength (kg / cm ² ) 480 480 480 500 Izod impact strength ⁽¹⁾ 3.5 3.8 5.5 3.8 Heat distortion temperature (℃) 93 93 90 96 Rockwell hardness (R) 92 93 90 92 Copper damage resistance ○ ○ ○ ○ Note (1): Unit: kg ・ cm / cm

Table 1 (continued) Example 5 Example 6 Example 7 Composition Resin component BPP or HPP type BPP1 BPP1 BPP4 compounding amount (wt%) 70 70 60 Talc type Ta-1 Ta-2 Ta-3 compounding amount ( % By weight) 30 30 40 Additives (parts by weight) Ph-AO 0.1 0.1 0.1 P-AO 0.1 0.1 0.1 MD 0.3 0.3 0.3 Properties of composition MFR (g / 10 min) 33 33 30 Tensile strength (kg / cm ² ) 350 310 330 Tensile elongation at break (%) 70 30 30 Flexural modulus (kg / cm ² ) 33 800 32000 38200 Bending strength (kg / cm ² ) 500 480 490 Izod impact strength ⁽¹⁾ 3.9 3.5 3.2 Thermal deformation temperature (° C) ) 95 92 98 Rockwell hardness (R) 92 92 93 Copper damage resistance ○ ○ ○

Table 1 (continued) Comparative Example 1 Comparative Example 2 Comparative Example 3 Composition Resin component BPP or HPP type BPP2 BPP5 HPP compounding amount (wt%) 70 70 70 Talc type Ta-3 Ta-3 Ta-3 compounding amount ( %) 30 30 30 Additives (parts by weight) Ph-AO 0.1 0.1 0.1 P-AO 0.1 0.1 0.1 MD 0.3 ─ 0.3 Composition characteristics MFR (g / 10 min) 30 28 40 Tensile strength (kg / cm ² ) 290 250 400 Tensile elongation at break (%) 35 30 4.4 Flexural modulus (kg / cm ² ) 22700 22000 40000 Bending strength (kg / cm ² ) 480 390 660 Izod impact strength ⁽¹⁾ 5.6 4.5 2.4 Heat distortion temperature (℃) ) 78 75 99 Rockwell hardness (R) 91 88 90 Copper damage resistance ○ × ○

Table 1 (continued) Comparative Example 4 Comparative Example 5 Comparative Example 6 Composition Resin component BPP or HPP type HPP BPP1 BPP1 compounding amount (wt%) 60 70 80 Talc type Ta-3 Ta-4 Ta-3 compounding amount ( 40 30 20 Additive (parts by weight) Ph-AO 0.1 0.1 0.1 P-AO 0.1 0.1 0.1 MD 0.3 0.3 0.3 Characteristic of composition MFR (g / 10 min) 38 34 34 Tensile strength (kg / cm ² ) 400 280 320 Tensile elongation at break (%) 3.2 30 150 Flexural modulus (kg / cm ² ) 45400 28000 25600 Bending strength (kg / cm ² ) 650 440 480 Izod impact strength ⁽¹⁾ 1.8 2.9 4.5 Heat distortion temperature (℃) ) 108 89 80 Rockwell hardness (R) ─ 90 92 Copper damage resistance ○ ○ ○

As is clear from Table 1, the thermoplastic resin compositions of Examples 1 to 7 are excellent in impact resistance, mechanical strength such as hardness and rigidity, heat resistance and copper damage resistance. Examples 1-3
And as is clear from Comparative Example 1, the heat of fusion (ΔH _m )
As the crystallinity decreases and the crystallinity decreases, the rigidity and heat resistance decrease. Propylene-from Examples 1-3 and Comparative Example 2
When the proportion of the ethylene copolymerized portion exceeds 20% by weight and the intrinsic viscosity of the propylene-ethylene copolymerized portion exceeds 5,
It can be seen that the mechanical strength and heat resistance decrease. Further, as is clear from Examples 1 to 7 and Comparative Examples 3 and 4, the impact resistance is low when the propylene homopolymer is used. Further, from Example 1 and Comparative Examples 5 and 6, impact resistance, rigidity and the like are deteriorated when the average particle diameter of talc exceeds 12 μm, and when the blending amount of talc is less than 25% by weight, heat resistance and rigidity are reduced. It turns out that is low.

[0046]

As described in detail above, the thermoplastic resin composition of the present invention has a propylene-ethylene copolymerized portion (intrinsic viscosity of 3 to 5 dl / g and an ethylene content of the copolymerized portion of 30 to 50). % By weight) and the heat of fusion (ΔH _m ).
And MFR, the propylene-ethylene block copolymer containing a propylene homopolymer portion satisfying a predetermined relationship, talc, an antioxidant, and a metal deactivator are contained. , Mechanical strength such as rigidity,
It has excellent moldability, heat resistance, and metal damage resistance.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yuji Fujita 3-1-1 Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Tonen Chemical Co., Ltd. Technical Development Center (72) Shinya Kawamura 1-cho, Toyota-cho, Aichi Prefecture Toyota Automobile Co., Ltd.

Claims (1)

[Claims] 1. A (a) having a melt flow rate (MFR) of 15 to 40 g / 10 minutes, and (i) a propylene-ethylene copolymerized portion (intrinsic viscosity of 3 to 5 dl / g). The ethylene content is 30 to 50% by weight.) 5
~ 20% by weight, and (ii) the propylene homopolymer portion 95 in which the heat of fusion (ΔH _m ) and the MFR satisfy the relational expression ΔH _m ≧ 24.5 + 1.583 log MFR 95
100 parts by weight of a resin component consisting of 50 to 75 parts by weight of a propylene-ethylene block copolymer containing 80% by weight, and (b) 25 to 50 parts by weight of talc having an average particle size of 5 μm or less, (c ) A thermoplastic resin composition comprising 0.01 to 2 parts by weight of an antioxidant and (d) 0.01 to 2 parts by weight of a metal deactivator.