JPH10101892A - Resin composition - Google Patents

Abstract

[PROBLEMS] To provide a resin composition having excellent impact resistance and coating properties, and enabling a molded article in which a decrease in impact strength due to coating is suppressed. SOLUTION: Component (A): a polyphenylene-based polymer having a propylene-ethylene block copolymer, component (B): ethylene-phenylene copolymer, component (C): triblock copolymer, component (D): And talc, and the component (A) polyolefin polymer has an MFR of 5 to 100 g / 1.
At 0 minutes, the intrinsic viscosity of the xylene-extracted component at 140 ° C. in tecarin at 2.0 ° C. is 2.0 to 5.0 g / dl, and the component (B) ethylene-propylene copolymer is:
The propylene content is 30 to 60% by weight, the MFR is 0.5 to 10 g / 10 min, and the component (C) is a copolymer of MFC having a MFR of more than 40 g / 10 min and 200 g / 10 min or less. The critical energy release rate between the union and the 100 ° C. xylene-insoluble component of the component (A) polyolefin polymer is at least 20 J / m ² , and the content of component (C) relative to the sum of components (A) to (D) The proportion is 2 to 10% by weight, the component (D) talc has an average particle size of 5 μm or less, and the content of the talc to the total of the components (A) to (D) is 5 to 25% by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition which is excellent in impact resistance and coating properties and enables a molded article having a small decrease in impact strength even when coated. The present invention relates to a resin composition suitable as a material for parts and the like.

[0002]

2. Description of the Related Art As a technique for improving the impact resistance of materials for automobile bumpers and interior / exterior parts, propylene-based polymers such as propylene homopolymer, propylene-ethylene block copolymer, and propylene random copolymer have been used. Ethylene-propylene copolymer (JP-B-60-3420), ethylene-α-olefin copolymer (JP-A-4-372637,
JP-A-5-331348, JP-A-6-192500, JP-A-Hei.
JP-A-6-192506) and blending of a hydrogenated product of a block copolymer of styrene and a diene (JP-A-7-53842) are reported.

[0003] In order to impart paintability to the above composition, a method of adding an EPR having an extremely low molecular weight is generally used. In addition, a method of adding a polyolefin modified with a compound having a polar group (JP-A-6-57838), particularly a method of adding a polyolefin modified with a compound having an unsaturated hydroxyl group (JP-A-5-39383) JP-A-3-157168, JP-A-5-117458, and JP-A-5-320442 have proposed a method of adding an oligomer having a polar group at the terminal.

[0004]

However, in order to exhibit sufficient paintability, it is necessary to add a large amount of an extremely low molecular weight EPR or a chemically modified compound in the material formed by the above method. In addition, mechanical properties such as impact resistance tend to be greatly reduced. In particular, the coating has a drawback that the impact resistance, particularly the DuPont impact strength, is reduced. The present invention has been made in order to solve such problems, and provides a resin composition which has excellent impact resistance and coating properties, and enables a molded article in which a decrease in impact strength due to coating is suppressed. It is intended to do so.

[0005]

The resin composition of the present invention comprises:
Component (A): a polypropylene polymer having a propylene-ethylene block copolymer, component (B): ethylene-propylene rubber, component (C): triblock copolymer, and component (D): talc The polypropylene polymer having the component (A) propylene-ethylene block copolymer has a melt flow rate of 5 to 100 g / 10 minutes measured at 230 ° C. under a load of 2.16 kg. Yes,
The intrinsic viscosity of the xylene-extracted component at 20 ° C in decalin at 140 ° C is 2.0 to 5.0 g / dl, and the component (B) ethylene-propylene rubber has a propylene content of 30%.
The melt flow rate is 0.5 to 10 g / 10 minutes measured at a load of 2.16 kg at 230.degree. C. and a component (C) triblock copolymer at 230.degree. The melt flow rate measured under the condition of a load of 2.16 kg is 40 g / 10
And the phase angle of the flat interface between the triblock copolymer and the xylene-insoluble component at 100 ° C. of the polypropylene polymer of the component (A) is -2.
The critical energy release rate at 20 ° C. to −12 ° is 20 J / m ² or more, and the content of the component (C) with respect to the sum of the components (A) to (D) is 2 to 10% by weight; D) The talc has an average particle size of 5 μm or less, and has a content of 5 to 25% by weight based on the total amount of the components (A) to (D).

In this resin composition, component (C)
Is a hydrogenated product of a styrene-butadiene-styrene triblock copolymer or a styrene-isoprene-styrene triblock copolymer, and preferably has a styrene content of 12 to 35% by weight.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. [Component (A): Polypropylene Polymer] The polypropylene polymer in the present invention needs to contain at least a propylene-ethylene block copolymer in its component. The propylene-based polymer in the present invention may be the propylene-ethylene block copolymer alone, but in addition to the propylene-ethylene block copolymer, a random copolymer or a propylene homopolymer (Homopolypropylene) can also be used in combination.

The comonomer of the random copolymer includes:
Ethylene, butene-1, hexene-1, octene-1,
Alpha-olefins other than propylene, such as 4-methylpentene-1, are preferred, and ethylene is particularly preferred.

In a block copolymer using ethylene as an α-olefin, ie, a propylene-ethylene block copolymer, an ethylene-propylene component in the molecule is dispersed in homopolypropylene, and the rubber component has a high impact resistance. Contributes to the development of sex.

The melt flow rate of the polypropylene polymer (according to JIS K7210 condition 14, hereinafter referred to as MFR) is preferably from 5 to 100 g / 10 minutes, and more preferably from 15 to 50 g / 10 minutes. When the MFR is less than 5 g / 10 minutes, the resulting resin composition has poor fluidity, deteriorates moldability, and particularly generates flow marks. On the other hand, if the MFR exceeds 100 g / 10 minutes, there arises a problem that the impact resistance and coatability of the resin composition are reduced. The polypropylene polymer is MFR
By melting and kneading (bisbreak) a compound having a low MFR (for example, MFR of 0.5 g / 10 min) in the presence of an organic peroxide, a compound having an MFR within the above range can be used.

The polypropylene polymer preferably has a xylene extractable component at 20 ° C. of 15 to 60% by weight. More preferably, it is 25 to 50% by weight. This component corresponds to the rubber component. The proportion of the xylene extractable component at 20 ° C. of the polypropylene polymer is
If the amount is less than 15% by weight, a large amount of a rubber component must be additionally added in order to develop impact resistance, so that there are problems such as an increase in cost and poor dispersion. On the other hand, if it exceeds 60% by weight, mutual adhesion tends to occur during the production of the polypropylene-based polymer, which is likely to cause trouble.

The propylene content in the xylene-extracted component of the polypropylene-based polymer at 20 ° C. is 40%.
Preferably it is 6060% by weight. More preferably, the content is 45 to 58% by weight. If the propylene content in the xylene-extracted component is less than 40% by weight, the resulting resin composition hardly exhibits impact resistance, and if it exceeds 60% by weight, heat resistance and surface hardness decrease.

Further, the polypropylene-based polymer is heated at 20 ° C.
The intrinsic viscosity of the xylene-extracted component in decalin at 140 ° C. is preferably 2.0 to 5.0 g / dl. More preferably, it is 2.0 to 3.5 g / dl. If the intrinsic viscosity of the component is less than 2.0 g / dl, the resulting resin composition does not exhibit impact resistance. On the other hand, if it exceeds 5.0 g / dl, there is a problem that not only the coatability of the obtained resin composition is inferior, but also poor dispersion is likely to occur and the impact resistance is lowered.

Further, the content of the polypropylene-based polymer with respect to the total of the components (A) to (D) constituting the resin composition of the present invention is preferably 55 to 85% by weight.
Further, the content is preferably 60 to 80% by weight. If the content is less than 55% by weight, as a result, the amount of added rubber increases, leading to an increase in cost. On the other hand, if it exceeds 85% by weight, the coatability of the obtained resin composition tends to be poor.

[Component (B): Ethylene-propylene rubber] The ethylene-propylene rubber used in the present invention preferably has a propylene content of 30 to 60% by weight. When the propylene content is less than 30% by weight, there is a problem that low-temperature impact resistance is not exhibited. On the other hand, 6
If it exceeds 0% by weight, heat resistance and surface hardness will decrease.

Further, the ethylene-propylene rubber may contain 230
The MFR at 0 ° C is preferably 0.5 to 10 g / 10 minutes.
Further, 0.7 to 8 g / 10 minutes is preferable. If the MFR is less than 0.5 g / 10 minutes, poor dispersion is caused, the surface appearance of the molded product is deteriorated, and the mechanical performance is also reduced. On the other hand, 10
If it exceeds g / 10 minutes, there is a problem that impact resistance is not exhibited. Further, when the molded product is taken out, the surface of the molded product is easily peeled.

The components (A) to (D) of the resin composition of the present invention
The content of the ethylene-propylene rubber relative to the sum of
Preferably it is 5 to 20% by weight. If the content is less than 5% by weight, impact resistance and paintability will be reduced. On the other hand, if it exceeds 20% by weight, the cost increases. The ethylene-propylene rubber can be produced using a Ti-based catalyst, a V-based catalyst, and a metallocene-based catalyst.

[Component (C): Triblock copolymer] The triblock copolymer used in the present invention has an effect of improving the DuPont impact strength after coating. The MFR of the triblock copolymer measured at 230 ° C. under a load of 2.16 kg is preferably more than 40 g / 10 min and 200 g / 10 min or less. Further, the MFR is preferably more than 50 g / 10 minutes and 180 g / 10 minutes or less. If the MFR is 40 g / 10 minutes or less, the decrease in DuPont impact strength after painting is severe. Meanwhile, 20
If it exceeds 0 g / 10 minutes, there is a problem that impact resistance, tensile elongation and the like are reduced.

Further, the phase angle of the flat interface between the triblock copolymer and the xylene-insoluble component at 100 ° C. of the polypropylene polymer of the component (A) is -2 ° to -12 °.
Energy release rate at the time of (hereinafter referred to as Gc)
Is preferably 20 J / m ² or more. If Gc is less than 20 J / m ² , there is a problem that the resulting resin composition has reduced impact resistance and the like.

Further, the content of the triblock copolymer with respect to the components (A) to (D) constituting the resin composition of the present invention is preferably 2 to 10% by weight. Furthermore, 2
~ 5% by weight is preferred. If the content of the triblock copolymer in the resin composition is less than 2% by weight, there is a problem that the DuPont impact strength after coating is greatly reduced.
On the other hand, if it exceeds 10% by weight, the resin composition becomes expensive, and there is a problem that improvement of various physical properties cannot be expected for the cost.

Further, the triblock copolymer is a hydrogenated product of a styrene-butadiene-styrene triblock copolymer (hereinafter referred to as SEBS), and preferably has a styrene content of 12 to 35% by weight. . In this case, if the styrene content is less than 12% by weight, there is a problem that impact resistance and heat resistance are reduced. On the other hand, if it exceeds 35% by weight, there is a problem that impact resistance is reduced.
It is also preferable that the triblock copolymer is a hydrogenated product of a styrene-isoprene-styrene triblock copolymer (hereinafter referred to as SEPS), and the styrene content is 12 to 35% by weight. In this case, if the styrene content is less than 12% by weight, there is a problem that impact resistance and heat resistance are reduced. On the other hand, if it exceeds 35% by weight, there is a problem that impact resistance is reduced.

These triblock copolymers can be produced by a commonly used anion living polymerization method. This involves sequentially polymerizing styrene, butadiene, and styrene to produce a triblock copolymer, followed by hydrogenation, and first producing a styrene-butadiene diblock copolymer, followed by a coupling agent. And then hydrogenating the triblock copolymer using a butadiene,
There is a method in which styrene is sequentially polymerized and then hydrogenated. In either case, a diblock copolymer, a homopolymer, or the like is produced, but the content thereof must be less than 10% by weight of the entire triblock copolymer. If the content of the diblock copolymer or homopolymer exceeds 10% by weight, there is a problem that rigidity is reduced.

[Component (D): Talc] The average particle size of talc used in the present invention is preferably 5 μm or less.
If the average particle size exceeds 5 μm, there is a problem that impact resistance, tensile elongation and the like are reduced. Further, the content of talc to the total of components (A) to (D) constituting the resin composition of the present invention is desirably 5 to 25% by weight. If it is out of this range, it is difficult to satisfy the elastic modulus, impact resistance, and the like suitable for automotive materials.

[Gc measurement method] In the present invention, Gc is a critical energy release rate of cracks existing at a flat interface between a triblock copolymer and a xylene-insoluble component of a propylene-ethylene block copolymer at 100 ° C. Is defined by In order to measure Gc, an asymmetric double cantilever beam method (hereinafter referred to as an ADCB method) is referred to: “Costantino-Creton, Dissertation, Cornell University,
1992). This is to allow cracks to grow along the interface. Conventional peel tests do not allow cracks to grow along the interface. For this reason, the crack penetrates into the softer material (that is, in the triblock copolymer), and the Gc at the interface cannot be measured accurately.

A parameter that determines the crack growth direction is a phase angle Ψ defined by the following equation. Ψ = tan ⁻¹ (K _II / K _I ) Here, K _I and K _II are stress intensity factors corresponding to mode I (tensile) and mode II (in-plane shear), respectively. Ψ depends on the geometry of the ADCB method, the elastic modulus of each material, Poisson's ratio, and crack length. Actually, evaluation is made by the boundary element method (BEM method) and the finite element method (FEM method).

In the present invention, it is necessary to measure Gc when Ψ is in the range of −2 ° to −12 °. Here, when the crack proceeds in the direction of the thin beam, Ψ is defined to be negative. If Ψ is smaller than -12 °, cracks at the interface penetrate into a thin beam, and there is a problem that Gc at the interface cannot be measured accurately. On the other hand, if Ψ is −2 ° to 0 °, crack growth at the interface is unstable, and there is a problem that Gc at the interface cannot be measured accurately as before. Furthermore, if Ψ exceeds 0 °, cracks will penetrate into the triblock copolymer and exactly
There is a problem that c cannot be measured.

In producing the resin composition of the present invention,
Uses additives such as heat, oxygen and light stabilizers, flame retardants, fillers, colorants, lubricants, plasticizers, and antistatic agents that are widely used in the synthetic resin and synthetic rubber fields. May be added within a range that does not essentially impair the properties of the resin composition of the present invention.

For example, examples of the antioxidant include the following. Dibutylhydroxytoluene, alkylated phenol, 4,4′-thiobis- (6-t-butyl-3-methylphenol), 4,4′-butylidenebis- (6-t-butyl-3-methylphenol), 2,
2'-methylenebis- (4-methyl-6-t-butylphenol), 2,2'-methylenebis- (4-ethyl-
6-t-butylphenol), 2,6-di-t-butyl-
4-ethylphenol, 1,1,3-tris- (2-methyl-4-hydroxy-5-t-butylphenyl) butane, n-octadecyl-3- (4-hydroxy-3,5
-Di-t-butylphenyl) propionate, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, dilaurylthiodipropionate, distearylthiodipropionate, Dimyristylylthiopropionate. Hindered phenol-based compounds include triethylene glycol-bis [3- (3-t-butyl-
5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5
-Di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6-
(4-hydroxy-3,5-di-t-butylanilino)
-1,3,5-triazine, pentaerythryl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylenebis [3- (3 5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate], N, N'-hexamethylenebis (3,
5-di-tert-butyl-4-hydroxy-hydrocinnamamide), 3,5-tert-butyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6 -Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris-
(3,5-di-t-butyl-4-hydroxybenzyl)
-Isocyanurate, octylated diphenylamine,
There is 2,4-bis [(octylthio) methyl] -o-cresol. Examples of the hydrazine type include N, N'-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine. In addition, phenolic antioxidants, phosphite antioxidants,
Thioether antioxidants, heavy metal deactivators and the like can be applied.

As the ultraviolet absorber, for example, 2-
(2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy -3 ', 5'-di-t
-Butylphenyl) -5-chlorobenzotriazole,
2-hydroxy-4-n-octoxybenzophenone,
Phenyl salicylate, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3 , 5-di-t
-Butyl-2-hydroxyphenyl) benzotriazole, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2-
(3,5-di-t-butyl-2-hydroxyphenyl)
-5-chlorobenzotriazole, 2- (3,5-di-
There are t-amyl-2-hydroxyphenyl) benzotriazole, 2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole, hydroxyphenylbenzotriazole derivatives and the like. Also, dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-
2,2,6,6-tetramethylpiperidine polycondensate, 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, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonic acid Bis (1,2,2,6,6-pentamethyl-
4-piperidyl), 2,4-di-t-butylphenyl-
3,5-butyl-4-hydroxybenzoate and the like.

The following can be used as the flame retardant, for example. Polybromodiphenyl oxide, tetrabromobisphenol A, brominated epoxy hexabromocyclododecane, ethylene bistetrabromophthalimide, brominated polystyrene dechlorane, brominated polycarbonate, polyphosphonate compound, halogenated polyphosphonate, triazine, red phosphorus, Tricresyl phosphate, triphenyl phosphate, crediphenyl phosphate, triallyl phosphate, trixylyl phosphate, trialkyl phosphate, trischloroethyl phosphate, trischloropropyl phosphate, tris (dichloropropyl phosphate), antimony trioxide, aluminum hydroxide, water An example is magnesium oxide. Further, silicone oil, stearic acid, calcium stearate, barium stearate, aluminum stearate, zinc stearate, magnesium stearate, carbon black, titanium dioxide, silica, mica, montmorillonite and the like may be added.

In addition to these additives, inorganic fillers may be added. Examples of the inorganic filler include fibrous materials such as barium titanate whiskers, calcium carbonate whiskers, magnesium sulfate whiskers, boron-based whiskers, carbon fibers and glass fibers, and particulate materials such as calcium carbonate and magnesium carbonate.

[Production Method] The resin composition of the present invention is produced by uniformly mixing the above-mentioned components, additives and the like. There is no particular limitation on the mixing method, and a method generally used in the field of synthetic resins may be applied. As a mixing method, a method of dry blending using a commonly used mixer such as a Henschel mixer, a tumbler, and a ribbon mixer, and a mixer such as an open roll, an extrusion mixer, a kneader, and a Banbury are used. And mixing while melting.

Of these methods, in order to obtain a more uniform resin composition, two or more of these mixing methods may be used in combination. For example, after dry-blending in advance, the mixture is melt-mixed. Even when dry blending is used in combination, or when one or two or more types of melt-mixing methods are used in combination, a pelletized product must be produced using a pelletizer before producing a molded product by a molding method described below. Is particularly preferred.

Of the above mixing methods, whether melt-mixing or molding by the molding method described below,
It must be carried out at a temperature at which the resin used melts. However, when carried out at a high temperature, the resin is thermally decomposed and degraded.
Performed at ~ 260 ° C.

The resin composition of the present invention may be formed into a desired shape by using an injection molding method, an extrusion molding method, a compression molding method, a hollow molding method, etc., which are generally performed in the field of synthetic resins. Alternatively, after forming into a sheet using an extruder, the sheet may be formed into a desired shape by a secondary processing method such as a vacuum forming method or a pressure forming method.

[0036]

The present invention will be described below in detail with reference to examples. Table 1
Various (A) polypropylene polymers shown in (1) to (4), (B)
A resin composition was produced using ethylene-propylene rubber, (C) a triblock copolymer, and (D) talc.

(A) Seven kinds of propylene-ethylene copolymers shown in Table 1 were used as the polypropylene-based polymer.

[Table 1] In Table 1, MFR was measured according to JIS K7210 condition 14. CE / P is the amount of xylene extracted from the propylene-ethylene block copolymer, Fp is the propylene content measured by NMR, and [η] E / P (dl / g) is the limit of the xylene extracted component. Viscosity.

[0038]

[Table 2] Fp is the propylene content measured by NMR.

[0039]

[Table 3]

In Table 3, the types of the triblock copolymer are as follows:
The hydrogenated product of the styrene-butadiene-styrene triblock copolymer was abbreviated as SEBS, and the hydrogenated product of the styrene-isoprene-styrene triblock copolymer was abbreviated as SEPS.
The styrene content (% by weight) measured by NMR was
Indicated by s. Further, 100% of the triblock copolymer and (A) propylene-ethylene block copolymer shown in Table 3 were used.
The critical energy release rate (Gc (J / m ² )) of a flat interface with a xylene-insoluble component at 0 ° C. is described in JP-A-7-286088.
And the asymmetric double cantilever beam method described in JP-A-7-292175. That is, the xylene-insoluble components at 100 ° C. of the triblock copolymer and the propylene-ethylene block copolymer are each press-molded to form a sheet having a thickness of about 1 mm, and they are superimposed and pressed at 200 ° C. for 10 minutes. It was thermocompression bonded with a machine. Thereafter, a crack was formed in the interface with a razor blade having a thickness of 0.25 mm, and the critical energy release rate was measured by the ADCB method. At this time, the thickness ratio of both beams was calculated and set by the boundary element method so that Ψ became −7 °. Gc
The values are shown in Table 6.

[0041]

[Table 4] The particle size of the component (D) talc was measured using a laser sedimentation method.

Each of the components shown in Tables 1 to 4 was blended according to the formulation shown in Table 5, dry-blended for 3 minutes using a Henschel mixer, and then coaxially twin-screw extruder (diameter 30 mm) set at 210 ° C. To produce a pellet of the resin composition. The pellets of each of the obtained resin compositions were molded using an injection molding machine set at 210 ° C., and test specimens for measuring the following physical properties were prepared and tested. Table 6 shows the test results. In Table 5, the content of each component used is shown in% by weight based on the entire resin composition.

The test method of each physical property is as follows. (1) Flexural Modulus (FM) Test A test piece produced by injection molding was measured at 23 ° C. in accordance with ASTM D790. Crosshead speed is 30
mm / min. (2) IZOD Impact Strength Test In accordance with ASTM D256, a test piece produced by injection molding was measured at −30 ° C. with a notch.

(3) Paintability test (cross-cut peelability evaluation test) A flat plate (80 mm × 240 mm ×
3 mm) was washed with ion-exchanged water, dried, coated with a chlorinated polypropylene primer of 10 μm, and dried at 80 ° C. for 30 minutes. Thereafter, a two-part urethane paint was applied at 30 μm and baked at 80 ° C. for 30 minutes. Then, cuts at 2 mm intervals intersecting at an angle of 90 ° were made in the coating film surface, and 100 grids were made. Next, a cellophane adhesive tape was strongly adhered thereon, and the adhesive tape was quickly peeled off. In Table 6, も の indicates that there was no peeling of the coating film, △ indicates that the coating film was partially peeled, and X indicates that more than half of the coating film on the grid crossed. (4) DuPont impact strength test A test piece for measuring DuPont impact strength by injection molding (1)
A 30 mm × 130 mm × 3 mm flat plate) was prepared, and the impact strength of the test piece before and after coating was determined as AS
Performed at -30 ° C according to TM D3029. The unit is kgfcm
It is. For painting, use chlorinated polypropylene primer
After applying 10 μm and drying at 80 ° C. for 30 minutes, a two-part urethane paint was applied at 30 μm and baked at 80 ° C. for 30 minutes.

[0045]

[Table 5]

[0046]

[Table 6]

From the results shown in Table 6, all of the resin compositions of the examples were excellent in coatability without peeling of the coating film.
It can be seen that a molded article with little decrease in DuPont impact strength can be obtained even after painting. On the other hand, when the (A) polypropylene polymer having a low [η] E / P of 1.6 dl / g is used, IZOD is deteriorated (Comparative Example 1). When the (A) polypropylene-based polymer having a high [η] E / P of 5.5 dl / g is used, IZOD, paintability and DuPont impact strength after painting are deteriorated (Comparative Example 2). When the MFR was extremely low, the performance was satisfied, but the appearance of the molded product was extremely poor (Comparative Example 3). On the other hand, if the MFR is too large, the IZOD and the DuPont impact strength after coating deteriorate (Comparative Example 4).

In Comparative Examples 5 to 8 in which the ethylene-propylene rubber was changed, Comparative Example 5 having a low MFR was Comparative Example 6 having a low coatability and a DuPont impact strength after coating and a high MFR.
Then, IZOD and DuPont impact strength after coating decrease. Furthermore, if the propylene content is lower than the proper range, IZ
OD, paintability, and DuPont impact strength after painting decrease (Comparative Example 7). On the other hand, when it is high, the rigidity decreases (Comparative Example 8).

The MF of the triblock copolymer used is
When R is low, the decrease in DuPont impact strength after coating is large (Comparative Example 9). Also, if the MFR is too high, IZOD will be inferior,
The decrease in DuPont impact strength after painting is large (Comparative Example 1)
0). Furthermore, if SEBS with small Gc is used, IZOD,
The decrease in DuPont impact strength after painting is large (Comparative Example 1)
1). If SEBS is not used, paintability and DuPo after painting
The decrease in nt impact strength is large (Comparative Example 12). In addition, when the particle size of talc is large, IZOD and DuPont impact strength decrease (Comparative Example 13).

[0050]

EFFECT OF THE INVENTION According to the resin composition of the present invention, it is possible to obtain a molded article having a high coating property and a high impact strength, in which the coating film is hardly peeled off, and in which the DuPont impact strength is small even when the coating is applied. It can be used in a wide range of fields such as interior and exterior parts of automobiles such as bumpers and parts for home appliances.

Claims (3)

[Claims] 1. A component (A): a polypropylene polymer having a propylene-ethylene block copolymer, a component (B): an ethylene-propylene rubber, a component (C): a triblock copolymer, and a component. (D): The propylene polymer containing talc and the component (A) propylene-ethylene block copolymer has a melt flow rate of 5 to 5 measured at 230 ° C. under a load of 2.16 kg. 100
g / 10 minutes, 140 ° C of xylene extract at 20 ° C
The intrinsic viscosity in decalin is 2.0 to 5.0 g / dl, and the component (B) ethylene-propylene rubber has a propylene content of 30 to 60% by weight and a load of 2.16 kg at 230 ° C. Melt flow rate measured at 0.5 to 10 g / 10
The melt flow rate of the component (C) triblock copolymer measured at 230 ° C. under a load of 2.16 kg is 40 g / min.
The phase angle of the flat interface between the triblock copolymer and the xylene-insoluble component of the component (A) at 100 ° C.
The critical energy release rate at -2 ° to -12 ° is 20 J / m ² or more, and the component (C) with respect to the sum of the components (A) to (D)
Talc has an average particle size of 5 μm or less,
A resin composition, wherein the content ratio of the components (A) to (D) is 5 to 25% by weight based on the total amount. 2. The component (C) is a hydrogenated styrene-butadiene-styrene triblock copolymer,
The resin composition according to claim 1, wherein the content of styrene is 12 to 35% by weight. 3. The component (C) is a hydrogenated styrene-isoprene-styrene triblock copolymer,
The resin composition according to claim 1, wherein the content of styrene is 12 to 35% by weight.