JPH09268240A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic resin composition that contains at least a plurality of propylene polymers, etc., which have specific physical properties, has excellent moldability and well-balanced mechanical properties in particular with excellent ductility, and is used for automobile parts. SOLUTION: This thermoplastic resin composition comprises (A) 10-50wt.% of (i) a propylene homopolymer having a melt flow rate (hereinafter abbreviated to MFR) of 2-30g/10min and an isotactic pentad fraction of 90-95%, and/or (ii) an ethylene-propylene random copolymer having an MFR of 2-30g/10min and 0.1-1wt.% of ethylene content, (B) 10-50wt.% of propylene homopolymer having an MFR of 50-1000g/10min, (C) 10-30wt.% of a styrene-based block copolymer elastomer which has an MFR of 0.5-40g/10min and polystyrene content of 10-30wt.% and is shown by formula I or II (PS is a polyethylene block; PEB is a polyethylene-butene block; (m)>=1), and (D) 10-40wt.% of talc having average particle size of 5μm or less.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to at least two specific aspects.
The present invention relates to a thermoplastic resin composition containing a propylene polymer, a styrene-based block copolymer elastomer and talc, and having particularly excellent injection moldability and good mechanical properties.

[0002]

2. Description of the Related Art Polypropylene is widely used in various fields because of its low density and good mechanical properties and moldability. However, since it is inferior in impact resistance and heat resistance, the ethylene-propylene block copolymer obtained by the multi-stage polymerization for the purpose of improving it has a rubber component such as ethylene-propylene copolymer rubber or ethylene-butene copolymer rubber. Various polypropylene-based resin compositions to which an inorganic filler such as talc and talc are added have been proposed.

For example, JP-A-1-149845 discloses that
(A) containing 5 to 12% by weight of a boiling xylene-soluble component having an ethylene content of 20 to 60% by weight, having an ethylene content of 1 to 7% by weight, and a melt flow rate of 15 to 15%;
Propylene-ethylene block copolymer 59 to 74% by weight, and (b) propylene content is 2 to 50 g / 10 min.
0-60% by weight and Mooney viscosity ML _{1 + 4} (100
C) of 35 to 20% by weight of an ethylene-propylene copolymer rubber having a specific surface area of 30000
Disclosed is a resin composition containing 3 to 6% by weight of talc having a mean particle size of 0.5 to 2.0 μm at a density of at least cm ² / g.

[0004]

In order to improve the impact resistance of conventional polypropylene, the content of the ethylene-propylene copolymer portion of the ethylene-propylene block copolymer as the polypropylene component was increased, Increasing the amount of a rubber component such as an ethylene-propylene copolymer rubber or an ethylene-butene copolymer rubber added later to the components causes a problem that the fluidity is deteriorated. Further, the addition of a large amount of a rubber component causes a problem that heat resistance and surface hardness are reduced.

[0005] On the other hand, in order to improve the production efficiency, the size and thickness of molded articles have been further developed, and there has been an increasing demand that molding materials have to have higher performance. In order to respond to such demands, it is essential to further increase the fluidity and performance of the molding material.However, in the case of a conventional composite material of an ethylene-propylene block copolymer and a polyolefin-based elastomer, this is not the case. There was a limit in improving physical properties.

Therefore, an object of the present invention is to provide a thermoplastic resin composition having excellent moldability and good mechanical properties, especially ductility.

[0007]

Means for Solving the Problems As a result of intensive research to solve the above problems, the present inventors have found that at least two propylene polymers having specific physical properties and a specific styrene block copolymer elastomer have specific physical properties. It was found that the problem of the present invention can be solved by blending and talc having a specific particle size, and the present invention has been completed.

That is, the thermoplastic resin composition of the present invention has (A) (1) a melt low rate of 2 to 30 g / 10.
Minute and isotactic pentad fraction 90-95
% Propylene homopolymer and / or (2) 10-50 wt% ethylene-propylene random copolymer having a melt flow rate of 2-30 g / 10 min and an ethylene content of 0.1-1 wt%, ) 10 to 50% by weight of propylene homopolymer having a melt flow rate of 50 to 1000 g / 10 minutes, and (C) a melt flow rate of 0.5 to 40 g / 10 minutes and a polystyrene portion content of 10 to 30% by weight. And has the following formula (I) or (II):

[0009]

Embedded image

[0010]

Embedded image (In the above formulas (I) and (II), PS is a polystyrene block, PEB is a polyethylene-butene block, and m ≧ 1) 10 to 30% by weight of a styrene block copolymer elastomer, (D) 10-40% by weight of talc having an average particle size of 5 μm or less
And

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic resin composition of the present invention is
This will be described in detail below.

[1] Composition Component (A) (1) Propylene Homopolymer The (A) (1) propylene homopolymer used in the present invention is a homopolymer of propylene, but a small amount in the polymer. (About 1% by weight or less) propylene and α-olefin, such as ethylene, butene-1, pentene-1,
4-methyl-pentene-1, hexene-1, heptene-
It may contain a crystalline random copolymer or a block copolymer with 1, 1, octene-1, etc.

The (A) (1) propylene homopolymer used in the present invention has a melt flow rate (230 ° C.,
Measured with a load of 2.16 kg, hereinafter referred to as MFR) is 2 to 3
It is 0 g / 10 minutes, preferably 2 to 20 g / 10 minutes.
If the MFR is less than 2 g / 10 minutes, the fluidity of the composition will be insufficient, while if it exceeds 30 g / 10 minutes, the ductility will be reduced.

The isotactic pentad fraction (IPF) is 90 to 95%, preferably 92 to 95%.
It is. When the isotactic pentad fraction (IPF) is less than 90%, the crystallinity of the propylene homopolymer is insufficient, and the rigidity, heat distortion temperature, etc. are insufficient, which is not preferable.
On the other hand, if it exceeds 95%, the ductility is particularly insufficient, which is not preferable.

By the way, the isotactic pentad fraction (IPF) is defined by A. Zambelli et al., Macromolecules, 6 ,
925 (1973), the isotactic fraction in the pentad unit in the polypropylene molecular chain measured using nuclear magnetic resonance spectrum with isotopic carbon ( ¹³ C-NMR), It is a fraction of propylene monomer units in which five monomer units are continuously isotactically bonded. However, regarding the attribution of peaks, Macromolecules (Macromolecules),
8 , 687 (1975). Specifically, the isotactic pentad unit is measured with the intensity fraction of the mmmm peak in all the absorption peaks in the methyl carbon region of the ¹³ C-NMR spectrum. The isotactic pentad fraction (hereinafter referred to as IPF) was measured for n-heptane insoluble matter according to the above method.

(A) (2) Ethylene-propylene random copolymer (A) (2) The ethylene-propylene random copolymer used in the present invention has an MFR of 2 to 30 g / 10.
Min, preferably 2 to 20 g / 10 min. MFR is 2
If it is less than 10 minutes, the fluidity of the composition will be insufficient, while 30
If it exceeds g / 10 minutes, the ductility is insufficient.

Further, if the ethylene content is less than 0.1% by weight, the ductility is insufficient, while if it exceeds 1% by weight, the rigidity and heat distortion temperature are insufficient, which is also unfavorable. Homopolymer and (A)
The ethylene-propylene random copolymer (2) may be used in combination.

(B) Propylene Homopolymer The (B) propylene homopolymer used in the present invention has an MFR of 50 to 1000 g / 10 min, preferably 1
It is from 00 to 600 g / 10 minutes. MFR is 50g / 10
If it is less than minutes, the fluidity of the composition is insufficient, while 1000 g /
If it exceeds 10 minutes, the ductility and the mechanical strength decrease, which is not preferable. The IPF of this propylene homopolymer
Is preferably 95% or more, more preferably 97% or more from the viewpoint of maintaining high crystallinity and rigidity and heat resistance.

Each propylene polymer as described above can be produced by various methods. Among them, as a preferable method, for example, in the presence of a stereoregular catalyst, a known slurry polymerization method, a solution polymerization method, a liquid phase polymerization method using an olefin monomer as a medium, or a gas phase polymerization method can be used for production. it can.

An example of the production method is, for example, titanium trichloride,
A combination of a transition metal compound catalyst component such as titanium tetrachloride or a catalyst component obtained by supporting them on a carrier mainly containing magnesium halide such as magnesium chloride and an organoaluminum compound such as triethylaluminum or diethylaluminum chloride. A propylene homopolymer is obtained by polymerizing propylene alone using a catalyst system. Further, ethylene as a comonomer is added to propylene, and the ethylene content in the copolymer is 0.1 to 1
An ethylene-propylene random copolymer is obtained by introducing and copolymerizing it so that the weight percentage becomes.

Further, the propylene homopolymers (A), (1) and (B) are reactors obtained by homomultistage polymerization of propylene so as to satisfy the respective MFR, IPF and blending ratio in the above-mentioned polymerization method. It can also be produced by blending.

Further, the propylene homopolymer or ethylene-propylene random copolymer obtained by the above-mentioned polymerization method is heat-treated in the presence of a treating agent such as an organic peroxide or a sulfur compound to obtain a desired MFR. Those adjusted to the value of (molecular weight degradation) can also be used. Especially,
The propylene homopolymer (B) is preferably one in which MFR is prepared by the method of reducing the above-mentioned molecular weight in order to reduce the loss due to the polymerization method and to improve the productivity as well as the mechanical properties. The heat treatment may be carried out, for example, by melt-kneading the propylene homopolymer in the presence of a treating agent such as an organic peroxide at 180 to 300 ° C. for 1 to 10 minutes in an extruder.

Here, usable organic peroxides are t-butyl hydroperoxide, dicumyl peroxide, di-t-butyl peroxide, benzoyl peroxide, and 2,5-dimethyl-2,5-dioxide. (T
-Butylperoxy) hexane, 2,5-dimethyl-
2,5-di (t-butylperoxy) hexyne-3, methylethylketone peroxide, and the like are mentioned, and among these, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and 2,5-dimethyl-2,5-di (t-butylperoxy) hexane are included. 5-dimethyl-2,5
-Di- (t-butylperoxy) hexyne-3 is preferred. Examples of sulfur compounds include trilauryl trithiophosphite and tristearyl trithiophosphite. These degrading agents are the desired M
Although it is used according to FR, it is usually preferably used in a proportion of 0.001 to 2 parts by weight with respect to 100 parts by weight of the propylene homopolymer, and may be used in the form of a masterbatch. (C) Styrenic Block Copolymer Elastomer The (B) styrene block copolymer elastomer used in the present invention has the following structural formula (I) or structural formula (II). ([Chemical 1] and [Chemical 2]
The same).

[0024]

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[0025]

[Chemical 6] (In the above formulas (I) and (II), PS is a polystyrene block, PEB is a polyethylene-butene block, and m ≧ 1) Such a styrene block copolymer is a monovinyl-substituted aromatic carbon It is a hydrogenated product of a block copolymer of hydrogen, preferably styrene, and a conjugated diene hydrocarbon, preferably 1.3-butadiene.

In the present invention, in particular, a block copolymer of a styrene polymer block and a 1.3-butadiene elastomer block is hydrogenated to produce a hydrogenated block copolymer. As described above, such a hydrogenated block copolymer has two or more blocks of a PS block and a PEB block, preferably a PS block and a PB block.
Those having 3 or more blocks of EB block and PS block are preferable as the physical properties used in the present invention.

The hydrogenated block copolymer is a styrene-ethylene-butene block copolymer elastomer (hereinafter also referred to as SEBS) or styrene-
It is also called an ethylene-butene copolymer elastomer (hereinafter also referred to as SEB). The hydrogenation amount of this SEBS or SEB is 90 mol% or more, and preferably one having no unsaturated bond is preferable from the viewpoint of weather resistance, recyclability and the like. Moreover, the MFR of the (C) styrene block copolymer elastomer is 0.5 to 40 g / 1.
It is 0 minutes, preferably 0.5 to 30 g / 10 minutes. MF
When R is less than 0.5, the fluidity is insufficient, the moldability is deteriorated, and the impact resistance is also insufficient. On the other hand, MFR is 40g / 1
If it exceeds 0 minutes, ductility and impact resistance become insufficient, which is not preferable.

The content of the polystyrene part constituting the (C) styrene block copolymer elastomer is
It is 10 to 30% by weight, preferably 15 to 30% by weight. When the content of the polystyrene portion is less than 10% by weight, the impact resistance is deteriorated. On the other hand, when the content is more than 30% by weight, stretching becomes insufficient, which is not preferable.

The (C) styrene block copolymer elastomer can be used in combination of two or more kinds as long as the contents of MFR and polystyrene portion are within the above ranges. (D) Talc The (D) talc used in the present invention has an average particle size of 5 μm measured by a laser diffraction / scattering particle size distribution analyzer.
m or less. If the average particle size of talc exceeds 5 μm, it is not preferable because rigidity and dimensional stability are insufficient. Further, talc is preferably subjected to a surface treatment with a modified silicone, a titanate-based coupling agent, or the like because the rigidity and heat resistance of the composition can be further improved.

The thermoplastic resin composition of the present invention may be added in a total amount of 100 parts by weight of the above-mentioned respective components (A), (B), (C) and (D) depending on its application such as interior and exterior materials for automobiles. On the other hand, it is preferable to add about 0.05 to 2 parts by weight each of an antioxidant, a heat stabilizer and a light stabilizer. If the amount of each component is less than 0.05 parts by weight, the respective effects are not sufficient, while if it exceeds 2 parts by weight, not only there is no further effect but also the physical properties of the composition are deteriorated, which is not preferable.

As the antioxidant used in that case,
Examples include phenol type and phosphorus type. Examples of phenol-based compounds include tetrakis [methylene-3
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate] methane, 2,6-di-t-butyl-4
-Methyl-phenol, tris (3,5-di-t-butyl-4-hydroxyphenyl) isocyanurate and the like.

As the phosphorus-based compound, for example, tris (2,4-di-t-butylphenyl) phosphite,
4,4'-butylidene-bis (3-methyl-6-t-butylphenyl-di-tridecyl) phosphite, 1,
1,3-tris (2-methyl-4-ditridecyl-phosphite-5-t-butyl) and the like.

Further, examples of the heat stabilizer include sulfur compounds such as distearyl thiopropionate and dilauryl thiopropionate.

Further, examples of the light stabilizer include bis (2,2,6,6-tetramethyl-4-piperziridine).
Sebacate, dimethyl-1 (2-hydroxyethyl)-
Condensation product of 4-hydroxyl-2,2,6,6-tetramethylpiperidine and succinic acid, poly [{6- (1,1,
3,3-Tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2 , 6,6-Tetramethyl-4-piperidyl)
Imino}], N, N'-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N-
(1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate and the like. The thermoplastic resin of the present invention has other additives such as a release agent for the purpose of modifying the thermoplastic resin.
An antistatic agent, a plasticizer, a flame retardant, a lubricant, a copper damage inhibitor, an organic or inorganic pigment and its dispersant, etc. can be added.

The above-mentioned various additives and pigments are generally added at the time of mixing the respective components, but a high-concentration masterbatch may be prepared in advance and blended after injection molding.

[2] Mixing ratio The mixing ratio of the various components as described above is 10 to 50% by weight, preferably (A) (1) propylene homopolymer and / or (2) ethylene-propylene random copolymer. Is 10 to 40% by weight, and (B) propylene homopolymer is 10 to 50% by weight, preferably 20 to 50% by weight.
And (C) the styrene block copolymer elastomer is 10 to 30% by weight, preferably 10 to 25% by weight, and the (D) talc is 10 to 40% by weight, preferably 1
0 to 30% by weight.

If the content of (A) (1) propylene homopolymer and / or (2) ethylene-propylene random copolymer is less than 10% by weight, the ductility of the obtained composition is lowered.
On the other hand, when it exceeds 50% by weight, rigidity, heat resistance and the like are deteriorated.
If the propylene homopolymer (B) is less than 10% by weight, the rigidity, heat resistance, hardness, etc. of the composition are likely to decrease, while if it exceeds 50% by weight, the strength, ductility, etc. are decreased.
(C) Styrene-based block copolymer elastomer is 10
If it is less than 30% by weight, impact resistance tends to decrease, while if it exceeds 30% by weight, strength, rigidity, heat resistance, hardness and the like decrease.

Further, if the (D) talc is less than 10% by weight, the rigidity and heat resistance are lowered, while if it exceeds 40% by weight, the ductility is lowered.

[3] Manufacturing Method The thermoplastic resin composition of the present invention is preliminarily dry-blended with the above-mentioned various components and then supplied to a single-screw extruder, a twin-screw extruder, a Banbury mixer, a kneader, etc. ~ 30
It can be produced by melt-kneading at 0 ° C, preferably 190 to 210 ° C.

[0040]

EXAMPLES Examples and comparative examples will be shown below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. The following resins, talc and additives were used as raw materials.

[1] Propylene homopolymer (HPP),
Ethylene-propylene random copolymer (RPP) and ethylene-propylene block copolymer (BPP) Table 1 Physical properties HPP-1 HPP-2 HPP-3 HPP-4 HPP-5 MFR ⁽¹⁾ 2 20 20 160 200 IPF ⁽²⁾ 94.9 94.8 97.7 97.5 97.8 Cv ⁽³⁾ 0 0 0 0 0 C ₂ ^{= (4)} 0 0 0 0 0 Table 1 (continued) Physical Properties HPP-6 HPP-7 HPP-8 RPP-1 RPP- 2 BPP MFR ⁽¹⁾ 300 600 160 3 5 85 IPF ⁽²⁾ 97.5 98.0 98.0--97.0 Cv ⁽³⁾ 0 0 0--9 C ₂ ⁽⁴⁾ 0 0 0 0.4 0.6 3.2 (Note) (1) MFR: Measured according to ASTM D1238 at 230 ° C and 2.16 kg load (unit: g / 10 minutes). (2) IPF: Isotactic pentad fraction (unit:%) measured using ¹³ C-NMR. (3) Cv: Content of the copolymer portion (room temperature xylene-soluble portion) in the propylene polymer (unit is% by weight). (4) C _2: Ethylene content in the propylene polymer (unit weight%).

Further, as the HPP-4 to HPP-7, the organic peroxide [2,5-dimethyl-2,5-di (t-butylperoxy) hexane] is preferably added to the HPP-3 prepared by the polymerization method. Added so that the MFR of
The molecular weight was lowered by melt extrusion reaction at ℃, and each MFR was prepared. In addition, RPP-1, RP
P-2, HPP-1, HPP-2, HPP-8 and B
PP is based on a polymerization method.

[2] SEBS and other elastomers Table 2 Physical Properties SEBS-1 SEBS-2 SEPS ⁽¹⁾ EPR ⁽²⁾ MFR ⁽³⁾ 2 8 0.5 0.8 PS ⁽⁴⁾ 29 13 13-
(Note) (1) SEPS: styrene-ethylene-propylene styrene block copolymer elastomer. (2) EPR: ethylene-propylene copolymer rubber (ethylene content 77% by weight). (3) MFR: 230 ° C according to ASTM D1238,
2. Measured under a load of 16 kg (unit: g / 10 minutes). (4) PS: Content of polystyrene portion in SEBS and SEPS (unit: weight%)

[3] Talc Talc: [Fuji Talc Co., Ltd., LMS300, average particle size 1.2 μm]

[4] Additive (1) Antioxidant-1: [Ciba-Geigy KK, Irganox 1010] (2) Antioxidant-2: [Asahi Denka KK, Mark 2112] (3) Heat stabilizer: [Sumitomo Chemical Co., Ltd., Sumilizer TPS] (4) Light stabilizer: [Ciba Geigy Co., Chimassorb 944]

Examples 1 to 7 and Comparative Examples 1 to 8 The above raw materials were blended in the proportions shown in Table 3, and in this case, 100 parts by weight of each blend was added with antioxidants-1 and 2, and heat stability. Each 0.2 parts by weight of the stabilizer and the light stabilizer are dry-blended with a super mixer and then charged into a twin-screw extruder (PCM-45 manufactured by Ikegai, L / D = 32) at 200 ° C. and a rotation speed of 200 rpm. Were melt-kneaded and extruded under the conditions of to obtain pellets.

Next, the obtained pellets were injected into an injection molding machine (TOSHIBA MACHINE IS-90B / cylinder temperature 210 ° C.,
A test piece for measuring physical properties was obtained by injection molding with a mold (50 ° C.). The following tests were carried out on the test pieces thus obtained, and the results are shown in Table 4.

Table 3 Composition (wt%) Example 1 Example 2 Example 3 Example 4 Example 5 Type of PP RPP-1 RPP-2 HPP-1 HPP-2 HPP-2 / HPP-5 / HPP -5 / HPP-5 / HPP-4 / HPP-4 Compounding amount 10/48 10/48 10/48 10/48 20/38 SEBS type SEBS-1 SEBS-1 SEBS-1 SEBS-1 SEBS-1 / SEBS -2 / SEBS-2 / SEBS-2 / SEBS-2 compounded amount 11/11 11/11 11/11 22 11/11 compounded amount of talc 20 20 20 20 20 Table 3 (continued) Composition (wt%) Implementation Example 6 Example 7 PP type HPP-2 HPP-2 / HPP-6 / HPP-8 compounding amount 26/32 10/48 SEBS type SEBS-1 SEBS-1 / SEBS-2 compounding amount 11/11 22 Talc 20 20 Table 3 (continued) Composition (wt%) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Types of PP HPP-3 HPP-3 HPP-3 HPP-3 HPP-4 / HPP-4 / HPP-4 / HPP-6 / HPP-7 Compounding amount 10/48 20/38 26/32 33/25 57 SEBS type SEBS-1 SEBS-1 SEBS-1 SEBS-1 SEBS-1 / SEBS -2 / SEBS-2 / SEBS-2 Compounding amount 22 11/11 11/11 11/11 23 Talc compounding amount 20 20 20 20 20 Table 3 (continued) Composition (wt%) Comparative Example 6 Comparative Example 7 Comparative Example 8 Type of PP BPP RPP-1 RPP-1 compounded amount 62 57 57 SEBS type SEBS-1 SEPS EPR compounded amount 18 23 23 Talc compounded amount 20 20 20

Table 4Physical property Example 1 Example 2 Example 3 Example 4 Example 5 MFR⁽¹⁾ 31 32 30 32 30 Tensile yield strength⁽²⁾ 240 238 239 237 236 Tensile elongation at break⁽³⁾ 600 600 600 600 600 Flexural modulus^(Four) 23500 23400 23600 23500 23500 Bending strength^(Five) 352 350 351 350 350 Izod Impact strength⁽⁶⁾ @ 23 ℃ 42 43 42 40 42 @ -30 ℃ 4.4 4.5 4.3 4.3 4.5 Heat distortion temperature⁽⁷⁾ 76 76 77 77 78 Rockwell hardness⁽⁸⁾ 76 76 76 76 76 Brittle temperature⁽⁹⁾ -20 -22 -21 -20 -22 Table 4 (continued)Physical property Example 6 Example 7 Comparative Example 1 Comparative Example 2 Comparative Example 3 MFR⁽¹⁾ 33 35 32 30 33 Tensile yield strength⁽²⁾ 235 236 237 236 235 Tensile elongation at break⁽³⁾ 600 600 500 500 500 Flexural modulus^(Four) 24000 23500 23500 23500 24000 Bending strength^(Five) 351 350 350 350 351 Izod Impact strength⁽⁶⁾ @ 23 ℃ 40 40 40 42 40 @ -30 ℃ 4.2 4.5 4.3 4.5 4.2 Heat distortion temperature⁽⁷⁾ 77 77 77 78 77 Rockwell hardness⁽⁸⁾ 76 76 76 76 76 Brittle temperature⁽⁹⁾ -21 -20 -20 -22 -21 Table 4 (continued)Physical property Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 MFR⁽¹⁾ 31 33 33 33 35 Tensile yield strength⁽²⁾ 235 231 230 220 220 Tensile breaking elongation⁽³⁾ 500 100 600 30 40 Flexural modulus^(Four) 23500 23900 23400 23100 23300 Bending strength^(Five) 350 366 348 344 335 Izod Impact strength⁽⁶⁾ @ 23 ℃ 41 21 26 10 12 @ -30 ℃ 4.4 3.9 3.0 3.0 2.4 Heat distortion temperature⁽⁷⁾ 77 77 74 72 73 Rockwell hardness⁽⁸⁾ 76 79 76 73 71 Brittle temperature⁽⁹⁾ -20 -15 -10 -3 -1 (Note) (1) MFR: Measured by ASTM D1238 at 230 ° C and 2.16 kg load (unit: g / 10 minutes). (2) Tensile yield strength: measured by ASTM D638 (unit: kgf / cm^Two ). (3) Tensile rupture elongation: measured by ASTM D638 (unit:%). (4) Flexural modulus: measured by ASTM D790 (unit: kgf / cm^Two ). (5) Bending strength: measured by ASTM D790 (unit: kgf / cm^Two ). (6) Izod impact strength: Measured at 23 ° C and -30 ° C according to ASTM D256 (unit: kgf · cm · cm). (7) Heat distortion temperature (HDT): 18.6 kgf / cm according to ASTM D648 ^Two Measured at (unit: ° C). (8) Rockwell hardness: measured by ASTM D785 (scale is R). (9) Brittleness temperature: measured by ASTM D746 (unit: ° C).

As is clear from Table 4, the compositions of Examples 1 to 7 have MFR values which are excellent in fluidity, and mechanical properties have a good balance particularly excellent in ductility. On the other hand, the compositions of Comparative Examples have a good balance of mechanical properties even though they have good fluidity. In particular, 2 specified in the present invention
The use of one propylene polymer other than the combined use of one type of propylene polymer, the one using a styrene-based elastomer such as SEPS or the one using an olefin-based elastomer such as EPR has poor ductility, while the one having good ductility has impact resistance. Properties, brittleness temperature, etc. are insufficient.

[0051]

Industrial Applicability The thermoplastic resin composition of the present invention has a good balance of excellent moldability and excellent ductility among mechanical properties. Therefore, the range of injection molding conditions can be widened, which facilitates the molding of thin and large-sized products.

Therefore, it is useful in products obtained by injection molding of industrial materials such as interior / exterior materials for automobile parts and home electric appliance parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Fujita 3-1, Chidori-cho, Kawasaki-ku, Kanagawa Prefecture Tonen Kagaku Co., Ltd. Technology Development Center

Claims (2)

[Claims] 1. The melt flow rate of (A) (1) is 2 to
Propylene homopolymer having 30 g / 10 minutes and isotactic pentad fraction of 90 to 95% and / or (2) melt flow rate of 2 to 30 g / 10 minutes and ethylene content of 0.1 to 1% by weight. Ethylene-propylene random copolymer of 10 to 50% by weight, (B) a melt flow rate of 50 to 1000 g / 10 min, a propylene homopolymer of 10 to 50% by weight, and (C) a melt flow rate of 0.5. ˜40 g / 10 min and the content of polystyrene part is 10˜30 wt%, and the following formula (I) or (II): Embedded image (In the above formulas (I) and (II), PS is a polystyrene block, PEB is a polyethylene-butene block, and m ≧ 1) 10 to 30 wt% of a styrene block copolymer elastomer , (D) 10-40% by weight of talc having an average particle size of 5 μm or less
A thermoplastic resin composition containing: 2. The thermoplastic resin composition according to claim 1, wherein the (B) melt flow rate is 50 to 100.
A thermoplastic resin composition in which a propylene homopolymer of 0 g / 10 min is a homopropylene polymer obtained by a polymerization method and subjected to a molecular weight reduction treatment.