JPH06107897A - Polypropylene resin composition for coated - Google Patents

Abstract

PURPOSE:To improve the resistances to heat, weather and yellowing by incorpo rating specific antioxidants and light stabilizer in a composition comprising a crystalline ethylene-propylene block copolymer, an elastomer and an inorganic filler. CONSTITUTION:The composition is prepared by incorporating 0.03-0.20 pts.wt. organophosphorus antioxidant, 0.05-0.30 pts.wt. hindered phenol antioxidant which contains no nitrogen atom and has a molecular weight of 500 or more, 0.05-0.40 pts.wt. nitrogenous hindered phenol antioxidant and 0.05-0.50 pts.wt. hindered amine light stabilizer having no N-H bond in 100 pts.wt. composition comprising 45-75wt.% crystalline ethylene-propylene block copolymer, 20-35wt.% elastomer and 5-15wt.% inorganic filler.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin composition which can be preferably used for various large automobile parts such as instrument panels, bumpers, linings, armrests, etc., especially for painted bumpers.

[0002]

2. Description of the Related Art Polypropylene-based resins have excellent mechanical strength, are inexpensive, and can relatively easily manufacture large-sized molded articles by injection molding. Therefore, in recent years, they have been widely used in automobile bumpers in place of polyurethane. Has become. Conventionally, unpainted products or all-painted products have been generally used for automobile bumpers, but in recent years, part of the bumpers has become unpainted due to design requirements. For this reason, polypropylene resins for bumpers have been required to have good weather resistance as well as good adhesion to coating films. Not only this, it has been required that the coating film does not discolor even when the bumper is exposed to light, heat, moisture or the like.

In the coating of bumpers, in order to reduce the cost and improve the productivity, a method in which the bumper after injection molding is washed with a halogen-based organic solvent, plasma-treated, and then coated is widely used. Has become.
However, if the bumper washed with the organic solvent is immediately subjected to the plasma treatment, the vapor of the organic solvent remaining on the bumper surface evaporates, which impedes the generation of plasma, so that there is a problem that the effective plasma treatment cannot be performed. Therefore, the bumper washed with a halogen-based organic solvent is dried in advance in a high temperature atmosphere to remove the surface organic solvent.

[0004]

In general, polypropylene resins are blended with antioxidants such as hindered phenols and light stabilizers such as hindered amines in order to improve weather resistance and light stability. Therefore, when the bumper formed of polypropylene resin is exposed to a high temperature atmosphere, these antioxidants and light stabilizers sometimes exude to the surface.

Then, these hindered phenolic antioxidants may be converted into quinoline, which may cause yellowing of the painted surface of the bumper. Further, there is a problem that the hindered amine light stabilizer on the surface deactivates the plasma ions and the bumper surface is not effectively modified. An object of the present invention is to solve such a problem in the conventional polypropylene resin bumper.

[0006]

The present invention provides a composition comprising a crystalline ethylene / propylene block copolymer, an elastomer, and an inorganic filler, which comprises (a) an organic phosphorus antioxidant and (b) a nitrogen atom. A high molecular weight hindered phenolic antioxidant not containing, (c) a hindered phenolic antioxidant containing a nitrogen atom, and (d) a specific amount of a hindered amine light stabilizer having no NH bond. And a polypropylene resin composition obtained by the method.

In the composition of the present invention, the organophosphorus antioxidant prevents the ethylene / propylene block copolymer and the thermoplastic elastomer from deteriorating at the time of melting and raising the MFR, whereby during injection molding. Suppress the generation of flow marks. In the composition of the present invention,
A hindered phenolic antioxidant containing nitrogen atoms,
It is used in combination with a high molecular weight hindered phenolic antioxidant containing no nitrogen atom for the following reason. That is, the hindered phenolic antioxidant containing a nitrogen atom has excellent antioxidative ability and hardly yellows due to light, heat, moisture, etc., but when used alone, it has sufficient heat resistance and weather resistance. The improvement effect cannot be obtained. On the other hand, the hindered phenol-based antioxidant containing no nitrogen atom is excellent in the effect of improving heat resistance and weather resistance, but has a drawback that it is easily yellowed by light, heat, moisture or the like. Therefore, by combining both hindered phenolic antioxidants, a sufficient effect of improving heat resistance and weather resistance is obtained, and yellowing resistance is improved.

Further, a hindered amine-based light stabilizer having no NH bond is used as the light stabilizer, but since this hindered amine-based light stabilizer hardly deactivates plasma ions, a bumper is formed by plasma treatment. The surface is effectively modified and excellent coating adhesion is obtained. The ratio of each component of the polypropylene resin composition of the present invention is as follows.

The proportion of each component of the crystalline ethylene / propylene block copolymer, elastomer and inorganic filler is such that the proportion of the crystalline ethylene / propylene block copolymer is 45 to 75% by weight, particularly preferably 50 to 70. % By weight, proportion of elastomer 20-35% by weight, particularly preferably 23-32% by weight, proportion of inorganic filler 5-15.
%, Particularly preferably 7 to 15% by weight.
However, the total amount of these components is 100% by weight.

When the proportion of the crystalline ethylene / propylene block copolymer is less than 45% by weight, only a polypropylene resin composition having low fluidity can be obtained, which makes it difficult to form a large molded article such as a bumper. On the other hand, if it exceeds 75% by weight, a molded product having a good balance of rigidity and impact resistance cannot be obtained. When the proportion of the elastomer is less than 20% by weight, only a molded product having insufficient impact resistance can be obtained, which is not suitable for bumpers. On the other hand, if it exceeds 35% by weight, a molded article having sufficient rigidity as a bumper cannot be obtained.

Even when the proportion of the inorganic filler is less than 5% by weight, a molded article having sufficient rigidity as a bumper cannot be obtained. On the other hand, if it exceeds 15% by weight, a bumper having sufficient impact resistance cannot be obtained. Next, the compounding ratio of the antioxidant and the hindered amine light stabilizer will be described.

The addition amount of the organic phosphorus antioxidant is 0.03 to
0.20 parts by weight, particularly preferably 0.03 to 0.10 parts by weight. And the addition amount of the high molecular weight hindered phenolic antioxidant containing no nitrogen atom is 0.0
5 to 0.30 parts by weight, particularly preferably 0.05 to 0.2
The amount of the nitrogen atom-containing hindered phenol-based antioxidant added is in the range of 0.05 to 0.40.
Parts by weight, particularly preferably 0.10 to 0.35 parts by weight. Furthermore, the range of the addition amount of the hindered amine light stabilizer having no NH bond is 0.05 to 0.50 parts by weight,
It is particularly preferably 0.20 to 0.40 parts by weight. However, the addition amount of these antioxidants and light stabilizers is a ratio with respect to the total amount of the crystalline ethylene / propylene block copolymer, the elastomer, and the inorganic filler as 100 parts by weight.

When the amount of the organic phosphorus antioxidant added is less than 0.03 parts by weight, the polypropylene resin deteriorates during melting and the MFR increases significantly, so that flow marks are likely to occur during bumper molding. Become. On the other hand, when the amount is more than 0.20 parts by weight, the exudation is severe and the adhesion between the coating film and the bumper deteriorates. Addition amount of high molecular weight hindered phenolic antioxidant containing no nitrogen atom is 0.05
When the amount is less than the weight part, the polypropylene resin is oxidatively deteriorated when melted, which is not preferable. On the other hand, if the addition amount is more than 0.30 parts by weight, yellowing of the bumper coated surface is likely to occur.

When the amount of the hindered phenolic antioxidant containing a nitrogen atom is less than 0.05 parts by weight, sufficient weather resistance cannot be ensured, and when it is more than 0.4 parts by weight, the coating film is There is a problem that the adhesion of the bumper cannot be secured. The ratio of the addition amount of the nitrogen atom-containing hindered phenolic antioxidant to the addition amount of the high molecular weight hindered phenolic antioxidant containing no nitrogen atom is:
The range of 1: 1 to 1: 3 (weight ratio) is preferable.

When the added amount of the hindered amine light stabilizer having no NH bond is less than 0.05 parts by weight, a bumper having sufficient weather resistance cannot be obtained. Hereinafter, each component of the polypropylene resin composition of the present invention will be described in detail. The crystalline ethylene / propylene copolymer has an ethylene content of 2 to 6% by weight and an MFR (melt flow rate) of 15 to 50 g.
/ 10 minutes, particularly preferably in the range of 17 to 40 g / 10 minutes.

The elastomer is preferably one whose main chain consists essentially of saturated bonds. Specifically, ethylene / propylene rubber (EPM), ethylene / butene copolymer (EBM), ethylene / α-olefin copolymer such as ethylene / propylene / diene terpolymer (EPDM), and hydrogenation Styrene-butadiene copolymer (SE
BS) and hydrogenated styrene-isoprene copolymer (SIB
S) and the like are preferably used.

As the inorganic filler, talc, mica, calcium carbonate, calcium oxide, calcium hydroxide, magnesium carbonate, magnesium hydroxide, magnesium oxide, magnesium sulfate, aluminum hydroxide, barium sulfate, glass powder, glass fiber, clay , Dolomite,
Mica, silica, alumina, potassium titanate whiskers, wollastenite, fibrous magnesium oxysulfate and the like are preferable. Of these inorganic fillers, those having an average particle diameter (spherical or tabular) or average fiber diameter (acicular or fibrous) of 5 μm or less are preferable.

The following are preferable as the antioxidant and the light stabilizer. Examples of the organic phosphorus antioxidant include tris (2,4-di-t-butylphenyl) phosphite, tris (monononylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (monononylphenyl) ) A mixture of phosphite and tris (dinonylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) 4,4'-biphenylenediphosphinic acid and the like are used.

As the high molecular weight hindered phenol containing no nitrogen atom, one having a molecular weight of 500 or more is used. Specifically, octadecyl-3- (3,5-di-t-butyl-4)
-Hydroxyphenyl) propionate, pentaerythyl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] 3,9-bis [1,1-dimethyl-2- (β- ( Three
-T-butyl-4-hydroxy-5-methylphenyl)
Propionyloxy) ethyl] -2,4,8,10-tetraoxaspiro (5,5) undecane, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] , 1,6-hexanediol-bis [3- (3,5-
Di-t-butyl-4-hydroxydiphenyl) propionate] and the like are preferable.

The hindered phenol type antioxidant containing a nitrogen atom is a triazine type, specifically, 1,3,5-tris (3,5-di-t-butyl-4).
-Hydroxybenzyl) -5-triazine-2,4,6
-(1H, 3H, 5H) trione, 2,4-bis- (n-octylthio) -6- [4-
Hydroxy-3,5-di-t-butylanilino) -1,
3,5-triazine, 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid, and the like are used.

Examples of the hindered amine light stabilizer having no N--H bond include dimethyl-1- (2-hydroxyethyl) -succinate.
4-hydroxy-2,2,6,6, -tetramethylpiperidine polycondensate, 1,2,3,4-butanetetracarboxylic acid-1,
2,2,6,6-Pentamethyl-4-piperidinol tridecyl alcohol condensate, 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1 , 2, 2,
6,6-Pentamethyl-4-piperidyl), 1,2,3,4-butanetetracarboxylic acid-tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl), bis (1,2,2) , 6,6-Pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3,5-di-t-butyl-4-
Hydroxyphenyl) propionyloxy] ethyl]-
4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine, and the like are particularly preferable.

Further, in the polypropylene resin composition of the present invention, ditridecyl-3,3'-thiodipropionate, 2-mercaptobenzimidazole, dilauryl-3,3'-thiodipropionate, dimyristyl-3, An organic sulfur-based antioxidant such as 3'-thiodipropionate, dilauryl-3,3'-thiodipropionate, pentaerythritol-tetrakis (β-laurylthiopropionate) or the like may be added. However, the blending amount of the organic sulfur-based antioxidant is preferably 0.05 parts by weight or less based on 100 parts by weight of the total amount of the crystalline ethylene / propylene block copolymer, the elastomer and the inorganic filler.

[0023]

EXAMPLES The present invention will be described in more detail below with reference to examples. The antioxidants, light stabilizers, crystalline ethylene / propylene resin used in the examples and comparative examples,
The abbreviations of the thermoplastic elastomer and the inorganic filler are as follows. [Antioxidant] Organic phosphorus antioxidant AO-1 ... Tris (2,4-di-t-butylphenyl)
Phosphite hindered phenolic antioxidant (high molecular weight without nitrogen atom) AO-2 ... Octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate (molecular weight 530. 9), AO-3 ... Pentaerythrityl-tetrakis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate] (molecular weight 1177.77), hindered phenolic antioxidant (containing nitrogen atom) AO-4 ... 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) -5-triazine-2,
4,6- (1H, 3H, 5H) trione, AO-5 ... 1,3,5-tris (4-t-butyl-3-)
(Hydroxy-2,6-dimethylbenzyl) isocyanuric acid, hindered phenolic antioxidant (no nitrogen atom and low molecular weight) AO-6 ... 2,6-di-t-butyl-4-methylphenol ( Molecular weight 220) Hindered amine light stabilizer HALS-1 ... 1,2,3,4-butanetetracarboxylic acid-1,2,2,6,6-pentamethyl-4-piperidinol tridecyl alcohol condensate, HALS- 2 ... Bis- (2,2,6,6, -tetramethyl-4-piperidinyl) sebacate Organic sulfur antioxidant SO-1 ... Ditridecyl-3,3'-thiodipropionate, [Crystalline ethylene propylene Copolymer] PP-1 ... Ethylene-containing 4.5% by weight, MER30
A crystalline ethylene / propylene copolymer having a composition of g / 10 minutes, AO-1 (organic phosphorus antioxidant) ... 0.05 parts by weight AO-3 (hindered phenol antioxidant) ...
Containing 03 parts by weight as an antioxidant PP-2 ... A crystalline ethylene / propylene copolymer similar to PP-1, containing only AO-3 as an antioxidant [ Elastomer] EPR ... Ethylene / propylene copolymer rubber having a propylene content of 25% by weight and a Mooney viscosity (M
L _{1 + 4} , 100 ° C.) of 20, EBR ... Ethylene / butene copolymer rubber,
Butene-1 content is 15% by weight, MFR (230 ° C) is 6
g / 10 minutes [Inorganic filler] F-1 ... Talc having an average particle diameter of 2.5 µ F-2 ... Light calcium carbonate having an average particle diameter of 0.07 µ In Examples and Comparative Examples, the polypropylene resin composition was used. The MFR, flexural modulus, Izod impact strength, appearance of the molded product, and adhesion of the coating film when applied to the molded product were measured under the following conditions.

[MFR] A polypropylene resin composition pellet was used and measured according to ASTM D-1238. [Flexural Modulus, Izod Impact Strength] Pellets of a polypropylene resin composition were injection molded under the conditions of a resin temperature of 220 ° C and a mold temperature of 50 ° C to obtain a test piece. The flexural modulus of this test piece was measured according to ASTM D790, and the Izod impact strength was determined by ASTM D.
According to 256, it measured at -30 degreeC.

[Appearance of Molded Product] A polypropylene resin composition was injection-molded to form a 140 mm × 360 mm × 3 mm flat plate test piece. It was visually observed whether or not a flow mark was generated on this test piece. When the flow mark occurs more than 20% of the flow area of the molded product x, when the flow mark occurs but the generated area is less than 20% of the flow area of the molded product △, the flow mark occurs When it was not seen, it was marked as ○.

[Adhesion between molded product and coating film, and yellowing resistance] A polypropylene resin composition was injection molded to obtain 50
The plate-shaped test piece of mm × 90 mm × 2 mm was used. The surface of the test piece was cleaned by exposing the test piece to saturated steam of 1,1,1-trichloroethane for 30 seconds. Then, it was placed in an oven set at 90 ° C. for 10 minutes, dried, and plasma-treated. The conditions of the plasma treatment were as follows.

Degree of vacuum 1.0 torr Microwave output 0.05 kw Processing time 0.3 seconds Gas flow rate 600 cc / min Processing gas Air For the test piece after plasma processing, acryl according to the following order (1) → (7) -Coated with melamine pearl mica. As paints, R320, R331, and R341 manufactured by Nippon Bee Chemical Co., Ltd. are used. R320 is used as a color base and R331 is used as a mica base.
And R341 was used for clearing.

(1) Color base coating, film thickness 15μ (2) After setting for 5 minutes, dried at 120 ° C. for 20 minutes (3) Mica base coating, film thickness 15μ (4) Flash for 3 minutes (5) Clear coating, film thickness 25μ (6) After setting for 5 minutes, bake coating at 120 ° C for 20 minutes (7) Leave at room temperature for 48 hours After immersing the test piece coated with acrylic-melamine pearl mica in water at 40 ° C for 240 hours, the coating film is a cutter knife Then, cuts were made in a grid pattern and divided into 100 1 mm square sections. Cellotape (registered trademark) was adhered from above, this cellotape (registered trademark) was peeled off, and the number of sections where the paint was peeled off was counted to evaluate the adhesion of the coating film.

Further, this test piece was put in a heating tank at 90 ° C. for 240 hours and examined for yellowing of the coating film to evaluate yellowing resistance. Regarding the degree of yellowing of the coating film before and after heating, Suga Test Instruments Co., Ltd. color computer SM-4
The color tone b value was measured using to obtain Δb. [Weather Resistance of Molded Article] Furthermore, the weather resistance of the test piece not coated was evaluated using a sunshine weather meter. The weather resistance is evaluated by the black panel temperature of 83 ° C.
Was performed under the conditions described above, and the weather resistance was evaluated by the length of time until cracks can be confirmed at a magnification of 50 times.

In order to ensure the appearance quality as a bumper, there is no flow mark (marked with a circle), there is no paint peeling (100/100), and yellowing resistance is Δ.
It is necessary that b is 1.40 or less and that it has weather resistance of 2000 hours or more. [Example 1] (1) PP-1 (containing AO-1 and AO-3) ... 63 wt% (2) EPM ... 27 wt% (3) F-1 ... 10 wt% and the above (1) ) To (3) with respect to 100 parts by weight in total, (a) a high molecular weight hindered phenolic antioxidant having no nitrogen atom AO-2 ... 0.1 parts by weight (b) a hindered substance having a nitrogen atom Phenol type antioxidant AO-4 ...... 0.2 parts by weight (c) Hindered amine light stabilizer HALS-1 ...... 0.3 parts by weight (d) Pigment carbon black ...... 0.1 parts by weight (e) Lubricant Magnesium stearate ... 0.2 parts by weight was blended, kneaded with a Henschel mixer, melted and kneaded with a twin-screw extruder set at 230 ° C., and then pelletized,
Pellets of the polypropylene resin composition were obtained.

The pellets were molded into test pieces, and the appearance, the adhesion to the coating film, and the weather resistance were measured according to the methods described above. The results are shown in Table 1. [Example 2] As a high molecular weight hindered phenolic antioxidant having no nitrogen atom, A was used instead of AO-2.
A polypropylene resin composition was obtained in the same manner as in Example 1 except that O-3 was used. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured.
The results are shown in Table 1.

Example 3 As a hindered phenolic antioxidant having a nitrogen atom, A was used instead of AO-4.
A polypropylene resin composition was obtained in the same manner as in Example 1 except that O-5 was used. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured.
The results are shown in Table 1.

Example 4 Organic Sulfur Antioxidant SO-
A polypropylene resin composition was obtained in the same manner as in Example 1 except that 1 was added. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured. The results are shown in Table 1. Example 5 A polypropylene resin composition was obtained in the same manner as in Example 1 except that the inorganic filler F-2 was added. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured. The results are shown in Table 1.

Example 6 A polypropylene resin composition was obtained in the same manner as in Example 1 except that EBM was used in combination with EPM as the thermoplastic elastomer. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured. The results are shown in Table 1.

[0035]

[Table 1]

Comparative Example 1 A crystalline ethylene / propylene block copolymer containing no organophosphorus antioxidant P
A polypropylene-based resin composition was obtained in the same manner as in Example 1 except that P-2 was used. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured. The results are shown in Table 2.

Comparative Example 2 Organic Phosphorus Antioxidant AO-1
A polypropylene resin composition was obtained in the same manner as in Comparative Example 1 except that the ratio was 0.40 part by weight. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured. The results are shown in Table 2. [Comparative Example 3] "AO-6" having a molecular weight of 220 and containing no nitrogen as a hindered phenol antioxidant fixing agent
A polypropylene-based resin composition was obtained in the same manner as in Example 1 except that was added. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured. The results are shown in Table 2.

Comparative Example 4 A polypropylene resin composition was obtained in the same manner as in Example 1 except that HALS-2 was used instead of HALS-1 as the hindered amine light stabilizer. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured. The results are shown in Table 2.

Comparative Example 5 AO-2, which is a hindered phenolic antioxidant containing a nitrogen atom, was used in the same amount as that of AO-4, which is a high molecular weight hindered phenolic antioxidant containing no nitrogen atom. Except that the amount was increased to 35 parts by weight.
A polypropylene resin composition was obtained in the same manner as in Example 1. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured. The results are shown in Table 2.

Comparative Example 6 A polypropylene resin composition was obtained in the same manner as in Example 1 except that 0.25 part by weight of AO-2 was used as the hindered phenol antioxidant. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured. The results are shown in Table 2.

Comparative Example 7 A polypropylene resin composition was obtained in the same manner as in Example 1 except that 0.2 part by weight of AO-3 alone was used as the hindered phenol antioxidant. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured. The results are shown in Table 2.

[Comparative Example 8] A polypropylene resin composition was obtained in the same manner as in Comparative Example 7 except that the proportion of AO-3 was changed to 0.25 part by weight. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured. The results are shown in Table 2. [Comparative Example 9] As the hindered phenolic antioxidant, 0.1 part by weight of AO-2, which is a high molecular weight hindered phenolic antioxidant containing no nitrogen atom, was used.
Was used in an amount of 0.2 parts by weight, and a hindered phenol-based antioxidant containing a nitrogen atom was not used. Other than this, Example 1
A polypropylene resin composition was obtained in the same manner as. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured. The results are shown in Table 2.

Comparative Example 10 Organic Sulfur Antioxidant SO
Example 1 except that the addition amount of -1 was increased to 0.2 parts by weight.
A polypropylene resin composition was obtained in the same manner as. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured. The results are shown in Table 2. [Comparative Example 11] Crystalline ethylene propylene block copolymer was increased to 80% by weight, and elastomer was added at 20% by weight.
A polypropylene resin composition was obtained in the same manner as in Example 1 except that the amount was reduced to 1. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured. The results are shown in Table 2.

Comparative Example 12 73% by weight of PP-1 and E
A polypropylene resin composition was obtained in the same manner as in Example 1 except that PM was 27% by weight and no inorganic filler was added. This was molded into a test piece, and the appearance, adhesion with a coating film, and weather resistance were measured. The results are shown in Table 2.

[0045]

[Table 2]

[0046]

EFFECT OF THE INVENTION The polypropylene resin composition of the present invention does not cause yellowing of the coated surface of the bumper even when it is molded and coated on a bumper or the like. Further, since the hindered amine light stabilizer on the surface does not react with plasma ions during the plasma treatment, the bumper surface is effectively modified and the adhesion to the coating film becomes good.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location // (C08L 53/00 23:00 9:00) (72) Inventor Ryomasa Hamada Sakai Osaka 3-1-1 Shinmachi, Chikko, Ube Kosan Co., Ltd. Sakai Plant Sakai Engineering Section (72) Inventor Kenji Kawazu 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd. (72) Inventor Shizuo Miyazaki Toyota City, Aichi Prefecture Town No. 1 Toyota Motor Corporation

Claims (2)

[Claims] 1. A crystalline organoethylene / propylene block copolymer 45 to 75% by weight, an elastomer 20 to 35% by weight, and an inorganic filler 5 to 15% by weight per 100 parts by weight of a composition. 0.03 to 0.20 parts by weight (b) Hindered phenolic antioxidant containing no nitrogen atom and having a molecular weight of 500 or more: 0.05 to 0.3
0 parts by weight (c) Hindered phenolic antioxidant containing nitrogen atom ...... 0.05 to 0.40 parts by weight (d) Hindered amine light stabilizer having no NH bond ...... 0.05 to 0 A polypropylene resin composition containing 50 parts by weight. 2. A crystalline organoethylene / propylene block copolymer 45 to 75% by weight, elastomer (20 to 35% by weight), and inorganic filler (5 to 15% by weight) relative to 100 parts by weight of the composition (a) organophosphorus. 0.03 to 0.20 parts by weight (b) Hindered phenolic antioxidant containing no nitrogen atom and having a molecular weight of 500 or more: 0.05 to 0.3
0 parts by weight (c) Hindered phenolic antioxidant containing nitrogen atom ...... 0.05 to 0.40 parts by weight (d) Hindered amine light stabilizer having no NH bond ...... 0.05 to 0 .50 parts by weight (e) Organic sulfur-based antioxidant: A polypropylene-based resin composition containing 0.10 parts by weight or less.