JPH11181222A - Inorganic filler-reinforced polyolefinic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inorganic filler-reinforced polyolefinic resin composition having excellent rigidity, heat resistance, impact strength, moldability, weatherability and long-term heat resistance with hardly generating a glass fogging phenomenon. SOLUTION: This inorganic filler-reinforced polyolefinic resin composition is composed of following components A to E. (A): 95-50 wt.% of an ethylene.propylene block copolymer comprising a propylene homopolymer part having >=0.906 g/cm<3> density and <=14×10<4> weight-average molecular weight (Mw) and an ethylene.propylene random copolymer part having >=45×10<4> Mw and <=20 wt.% content in the block copolymer. (B): 5-50 wt.% of an inorganic filler, (C): a non-alkaline metal salt of a fatty acid having >=600 Mw and >=110 deg.C melting point in an amount of 0.1-5 pts.wt. to 100 pts.wt. of the component B, (D): an N-methyl type hindered amine-based stabilizer in an amount of 0.01-1 pt.wt. to total 100 pts.wt. of the components A and B, (E): a hindered phenolic antioxidant having >=110 deg.C melting point in an amount of 0.01-1 pt.wt. to total 100 pts.wt. of the components A and B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an inorganic filler reinforced polyolefin resin composition having excellent injection moldability, high mechanical strength and high impact strength, excellent weather resistance and long-term heat resistance, and extremely low occurrence of glass haze. It is about things.

[0002]

2. Description of the Related Art Conventionally, polyolefin resins have been widely used as materials for industrial parts because of their excellent mechanical properties, electrical and chemical stability, and easy moldability. Further, a composition to which an inorganic filler, particularly talc is added in order to enhance the rigidity and heat resistance of these polyolefin resins is also known. For automotive parts, sunlight,
For parts that are exposed to high temperatures for a long time from light irradiation, such as the stability to light (light resistance and weather resistance) of a lamp light source, etc.
Stability of parts exposed to high temperatures for a long time due to radiation and conduction (long term thermal stability), stability of parts exposed to high temperatures while contacting other metal parts such as aluminum, copper, brass (copper resistant) Harmful properties) are required. For these reasons, various additives are generally added to enhance the stability performance of each.However, in many parts, for example, the exterior material has weather resistance and long-term heat resistance, and the interior material has light resistance. Long-term heat resistance and glass haze are required, case materials are required to have long-term heat resistance and copper damage resistance, and lamps are required to have light resistance, long-term heat resistance and glass haze, respectively. Usually, multiple stability is required at the same time.

On the other hand, when the above-mentioned stability is imparted to an inorganic filler-reinforced polyolefin resin, the inorganic filler and these additives have a large antagonistic action, and sufficient stability cannot be imparted. It is considered that the cause is that various additives are collected due to the adsorptivity of the inorganic filler, and the dispersion in the polyolefin resin is hindered. For this reason, it is conceivable to perform surface treatment on the inorganic filler with an aminosilane-based treatment agent or a titanate-based treatment agent to suppress the adsorption of additives, but this increases the cost and does not always provide a sufficient effect.

Further, a lubricant such as a fatty acid or a fatty acid amide can be added to suppress the adsorption of the additive to the inorganic filler. However, when a lubricating material is blended, it has an effect of accelerating the bleed-out of itself or an additive, and thus often deteriorates mold contamination and glass haze. The glass haze phenomenon means that various additives, lubricants, antistatic agents, etc., from plastic products such as instrument panels, high-mount stop lamp housings, and synthetic fabrics, are exposed to high temperatures and vaporized, causing the windshield or rear glass, etc. Is a phenomenon that adheres, solidifies, and fogs on a transparent surface such as glass. The glass haze phenomenon is a serious problem, especially for products such as interiors and lighting fixtures. To prevent this, measures such as reducing the amount of various additives have been taken. It was inevitable.

[0005]

Accordingly, the present invention is excellent in mechanical performance such as rigidity, heat resistance and impact strength, excellent in moldability such as injection molding, and further excellent in weather resistance and long-term heat resistance. Another object of the present invention is to provide an inorganic filler-reinforced polyolefin-based resin composition suitable for automobile interior materials and lamp housing materials, which is extremely low in occurrence of a glass haze phenomenon.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above problems, and as a result, have found that a resin having a specific property
The present invention has been completed based on the finding that the above object can be achieved by blending a specific amount of an additive having a specific property. That is, the inorganic filler-reinforced polyolefin-based resin composition of the present invention is characterized by comprising the following components (A) to (E). Component (A): a propylene homopolymer portion having a density of 0.906 g / cm ³ or more and a molecular weight of less than 140,000, a weight average molecular weight of 450,000 or more, and a proportion occupying 20% by weight in the block copolymer Ethylene / propylene block copolymer comprising less than ethylene / propylene random copolymerized portion 95 to 50% by weight Component (B): 5 to 50% by weight of inorganic filler Component (C): Weight average molecular weight of 600 or more, melting point Is a non-alkali metal salt of a fatty acid having a temperature of 110 ° C. or higher. 0.1 to 5 parts by weight based on 100 parts by weight of inorganic filler Component (D): N-methyl hindered amine stabilizer Total of component (A) and component (B) 0.01 to 1 part by weight per 100 parts by weight Component (E): hindered phenolic antioxidant having a melting point of 110 ° C. or more Total 100 parts by weight of component (A) and component (B) 0.01 to 1 part by weight for

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION

[I] Inorganic filler reinforced polyolefin resin composition (1) Constituent (A) Ethylene / propylene block copolymer [Component (A)] Component (A) constituting the inorganic filler reinforced polyolefin resin composition of the present invention. The ethylene-propylene block copolymer has a density of 0.906 g / cm ³ or more,
It is preferably 0.965 to 0.909 g / cm ³ , particularly preferably 0.907 to 0.908 g / cm ³ , and the weight average molecular weight is less than 140,000, preferably 90,000 to 135,000, particularly preferably 100,000 to 100,000. A propylene homopolymer portion of 130,000 and a weight average molecular weight of 450,000 or more, preferably 470,000 to 1,200,000, particularly preferably 500,000 to 1.1 million, and a proportion of less than 20% by weight in the block copolymer, preferably Is an ethylene / propylene block copolymer comprising 5 to 18% by weight, particularly preferably 7 to 15% by weight, of an ethylene / propylene random copolymerized portion. If the density of the propylene homopolymer portion is less than the above range, the strength, rigidity and heat resistance are lowered, and a disadvantage arises in that the decrease in strength, rigidity and heat resistance associated with the copolymer portion cannot be covered. On the other hand, when the weight average molecular weight exceeds the above range, the fluidity of the inorganic filler-reinforced polyolefin-based resin composition is low, resulting in a drawback that the moldability is deteriorated. Further, when the weight average molecular weight of the ethylene / propylene random copolymer portion is less than the above range, there is a disadvantage that the effect of improving impact strength is poor. On the other hand, if the proportion in the block copolymer exceeds the above range, there is a disadvantage that the strength, rigidity and heat resistance are significantly reduced.

(B) Inorganic Filler [Component (B)] As the inorganic filler of the component (B) constituting the inorganic filler-reinforced polyolefin resin composition of the present invention, a plate-like inorganic filler and other forms of inorganic filler are mainly used. There are inorganic fillers, and specific examples of the plate-like inorganic filler include, for example, alumina, aluminum hydroxide, kaolin clay, iron oxide, sericite, molybdenum disulfide, barite (barium sulfate), vermiculite, Examples include talc, mica, glass flake, and the like. In addition, as other forms of inorganic filler, specifically, for example, calcium silicate, magnesium oxide, amorphous, cubic or spindle-shaped, fibrous calcium carbonate, gypsum, carbon black, titanium oxide, quartz, etc. Can be mentioned. One of these inorganic fillers may be used alone, or two or more thereof may be used in combination. Among these inorganic fillers, plate-like inorganic fillers are preferable, and talc, mica, glass flake, and the like are particularly preferable. As the plate-like form of these suitable plate-like inorganic fillers, the average value of the aspect ratio showing the ratio of the length to the thickness in either the vertical or horizontal direction is preferably 3 or more, particularly preferably 4 or more.
That is all. Among them, talc having an average particle diameter of 1 to 10 μm and a particle size distribution of substantially 25 μm or less as a whole, and 95% or more of 15 μm or less and 80% or more of 10 μm or less and 5 to 50% of 5 μm or less is preferable.

(C) Non-alkali metal salt [Component (C)] The non-alkali metal salt of the component (C) constituting the inorganic filler-reinforced polyolefin resin composition of the present invention preferably has a weight average molecular weight of 600 or more, and more preferably Is 630-90
0, particularly preferably 650 to 850, melting point of 110 ° C. or higher, preferably 115 to 240 ° C., particularly preferably 12
It is a non-alkali metal salt of a fatty acid at 0 to 230 ° C. Specifically, for example, aluminum stearate (molecular weight:
610, melting point: 145 ° C), calcium stearate (molecular weight: 606, melting point: 148 ° C), zinc stearate (molecular weight: 631, melting point: 117 ° C), aluminum oleate (molecular weight: 606, melting point: 135 ° C), behen Calcium acid (molecular weight: 718, melting point: 142 ° C.),
Magnesium behenate (molecular weight 702, melting point: 115
° C), zinc behenate (molecular weight: 743, melting point: 115)
° C), calcium 1,2-vidroxiestearate (molecular weight: 638, melting point: 142 ° C), magnesium 1,2-vidroxiestearate (molecular weight: 622, melting point: 2)
22 ° C.), zinc 1,2-vidroxcystearate (molecular weight: 663, melting point: 145 ° C.) and the like.

If the weight-average molecular weight of the non-alkali metal salt is less than the above range, the diffusion rate in the product is high, bleeding out to the product surface is liable to occur, and volatilization is easy. This causes a disadvantage. Further, if the melting point is less than the above range, the temperature becomes lower than the maximum temperature of the use environment, and it is easily vaporized and volatilized. In addition, there is a disadvantage that the glass is solidified and adhered and the glass haze phenomenon is deteriorated. . Considering the maximum temperature of the environment in the automobile and the test standards of each company, the melting point is preferably 110 ° C. or more.

(D) N-methyl hindered amine stabilizer [Component (D)] The N-methyl hindered amine stabilizer of component (D) constituting the inorganic filler-reinforced polyolefin resin composition of the present invention includes: Specifically, for example, Adekastag LA-52 (manufactured by Asahi Denka Kogyo KK): Tetrakis (1,
2,2,6,6-pentamethyl-4-piperidyl)-
1,2,3,4-butanetetracarboxylate, ADK STAG LA-62 (manufactured by Asahi Denka Kogyo): bis (1,
2,2,6,6-pentamethyl-4-piperidyl) di (tridecyl) -1,2,3,4-butanetetracarboxylate, CHIMASSORB 199FL (manufactured by Ciba Specialty Chemicals): N, N'- Bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] chloro-1,3,5-
Triazine condensates and the like can be mentioned. In the stabilizers other than the N-methyl hindered amine-based stabilizer, for example, the adsorption to the inorganic filler is less than that of the N-H hindered amine-based stabilizer, the weather resistance is excellent, and the long-term heat resistance is high. . For this reason, the total amount of various additives can be reduced, which leads to suppression of glass haze. Further, since it has a large molecular weight and low volatility as compared with the NH type hindered amine-based stabilizer, the glass haze phenomenon is less likely to occur.

(E) Hindered phenolic antioxidant [Component (E)] The hindered phenolic antioxidant of the component (E) constituting the inorganic filler reinforced polyolefin resin composition of the present invention has a melting point. The temperature is desirably 110 ° C. or higher. The melting point is easier to evaporate than the maximum temperature of the use environment, and it is easy to solidify and adhere to the glass surface. Considering the maximum temperature of the environment in the car and the test standards of each company, the melting point is 110
It is preferable that the temperature is not lower than ° C. Specific examples of such a hindered phenol-based antioxidant include, for example, pentaerythrityl-tetrakis [3- (3,5-di-t
-Butyl-4-hydroxyphenyl) propionate:
IRGANOX 1010FP (manufactured by Ciba-Geigy),
Melting point 117-120 ° C, N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide): IRGANOX 1098 (manufactured by Ciba Specialty Chemicals) Melting point 156-161 ° C ,
1,3,5-trimethyl-2,4,6-tris (3,5
-Di-t-butyl-4-hydroxybenzyl) benzene: IRGANOX 1330 (manufactured by Ciba Specialty Chemicals), melting point 240-245 ° C, Tris-
(3,5-di-t-butyl-4-hydroxybenzyl)
-Isocyanurate]: IRGANOX 3114 (manufactured by Ciba Specialty Chemical Co., Ltd.), melting point 218-22
3 ° C, 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate: CYANOX 1790 (manufactured by Scitech) Melting point 155 to 159 ° C, (2,2′- Methylenebis [4-methyl-6-t-butylphenol]): CYANOX
2246 (manufactured by Scitech) Melting point 125 to 128 ° C,
3,9-bis [2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) -propionyloxy]
-1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane: Sumilizer
GA-80 (manufactured by Sumitomo Chemical Co., Ltd.).

Among the stabilizers other than the above-mentioned hindered phenolic antioxidants, for example, the use of a thioether-based antioxidant alone has an antagonistic effect with the hindered amine-based light stabilizer and tends to lower the weather resistance. Furthermore, since it has a low melting point, it is easy to volatilize, which has an adverse effect on glass haze. However, it is very effective for improving long-term heat resistance, and is economical. Therefore, thioether-based antioxidants having a high molecular weight (preferably having a molecular weight of 1,000
Is added only to the necessary minimum amount (preferably less than 0.1 part by weight), and it is preferable to use it together with the above hindered phenolic antioxidant. Such thioether-based antioxidants include, for example, 2-[[2,4,8,10-
Tetrakis (1,1-dimethylethyl) dibenzo [d,
f] [1,3,2] dioxaphosphepin-6-yl] oxy] -N, N'-bis [2-[[2,4,8,
10-tetrakis (1,1-dimethylethyl) dibenzo [d, f] [, 3,2] dioxaphosphepin-6
Yl] oxy] -ethyl] ethanamine: IRGAFOS
12 (manufactured by Ciba Specialty Chemicals), molecular weight 1465, melting point 205 ° C, pentaerythritol-tetrakis (3-lauryl-thiopropionate): Seanox 412S (manufactured by Cipro Kasei), molecular weight 1,162, melting point 49-52 ° C, etc. Can be mentioned.

(F) Other Additives (Optional Components) In addition to the above essential components, other additives can be blended as long as the effects of the present invention are not significantly impaired. As other additives, for example, a lubricant, a nucleating agent, a neutralizing agent,
Surfactants, processing stabilizers, ultraviolet absorbers, heat resistance improvers, weather resistance improvers, antistatic agents, metal deactivators, flame retardants, flame retardants, dispersants, colorants, flow improvers, metal corrosion Inhibitors, fungicides, phenol-based, sulfur-based, phosphorus-based antioxidants, benzophenone-based and benzotriazole-based weathering deterioration inhibitors, foaming agents, crosslinking agents, and the like can also be added.

(2) Compounding ratio The propylene / ethylene block copolymer of the component (A) is 95 to 50% by weight, preferably 90 to 60% by weight, particularly preferably 85 to 65% by weight, and the component (B) The inorganic filler of 5) is preferably 5 to 50% by weight, preferably 10 to 40% by weight, particularly preferably 15 to 35% by weight.
0.1 to 5 parts by weight, preferably 0.2 to 0 parts by weight
To 3 parts by weight, particularly preferably 0.5 to 1.5 parts by weight, and the N-methyl hindered amine-based stabilizer of the component (D) is based on 100 parts by weight of the total of the components (A) and (B). 0.01 to 1 part by weight, and the hindered phenolic antioxidant of the component (E) is preferably 0.01 to 1 part by weight based on 100 parts by weight of the total of the component (A) and the component (B). Is 0.02 to 0.5 part by weight, particularly preferably 0.05 to 0.5 part by weight.
It is blended in a proportion of 0.25 parts by weight.

If the amount of the ethylene / propylene block copolymer of the component (A) is less than the above range, the impact strength is remarkably reduced. On the other hand, if the amount exceeds the above range, the rigidity and heat resistance are insufficient. Disadvantages occur. If the amount of the inorganic filler of the component (B) is less than the above range, the reinforcing effect is poor and sufficient mechanical strength, rigidity and heat resistance cannot be obtained. There is a disadvantage in that the reinforcing effect reaches saturation and conversely decreases. If the amount of the non-alkali metal salt of the fatty acid as the component (C) is less than the above range, the adsorption of various additives to the inorganic filler cannot be sufficiently suppressed,
The drawback is that sufficient stability cannot be obtained.On the other hand, if it exceeds the above range, bleed out of the non-alkali metal salt of the fatty acid itself to the product surface and bleed out of various stabilizers will worsen the glass haze phenomenon. There is a drawback of doing so. If the amount of the N-methyl hindered amine-based stabilizer of the component (D) is less than the above range, the effect of improving the weather resistance cannot be obtained. On the other hand, if the amount exceeds the above range, the glass haze phenomenon occurs. Disadvantageously worsens. Further, if the amount of the hindered phenolic antioxidant of the component (E) is less than the above range, sufficient heat stability cannot be obtained. On the other hand, if the amount exceeds the above range, a glass haze phenomenon may occur. The disadvantage of worsening occurs.

(3) Production of Resin Composition (A) Kneading The inorganic filler-reinforced polyolefin resin composition of the present invention comprises the above-mentioned components in a conventional extruder, Banbury mixer, roll, Brabender plastograph, kneader It is manufactured by kneading at a set temperature of 180 to 250 ° C. using a Brabender or the like, and among these, it is preferable to manufacture using an extruder, particularly a twin-screw extruder. (B) Molding The molding method of the inorganic filler-reinforced polyolefin-based resin composition of the present invention is not particularly limited, and injection molding, extrusion molding, and hollow molding are possible. In view of this, the injection molding method is most suitable.

[II] Applications Since it is a material capable of exhibiting the above-mentioned performance, it can be processed into various molded products such as automobile parts, home electric appliance parts, OA equipment parts, and housing building material parts. Parts applications, such as instrument panels, door trims,
It is preferably used for automotive interior parts such as pillar trims and console boxes, and lamp housing materials such as head lamp housings, rear lamp housings, and high mount stop lamp housings.

[0019]

The present invention will be described more specifically with reference to the following examples and comparative examples. [I] Evaluation method Evaluation in Examples and Comparative Examples was performed by the following methods. MFR : MFR conformed to JIS-K7210. Flexural modulus : The flexural modulus was in accordance with JIS-K7203. Izod (IZOD) impact strength : Izod (IZO
D) Impact strength was in accordance with JIS-K7110. Formability : The moldability when forming a 120 × 120 × 2 mm flat plate was determined based on the following criteria. A: It has high fluidity and can be molded under ordinary molding conditions for polypropylene resin. B: Although the fluidity is low, it can be molded under the molding conditions of a polypropylene resin having a high temperature and a high pressure. C: Low fluidity, molding cannot be performed under high-temperature, high-pressure conditions, stable injection molding conditions are narrow, and unstable.

Weather resistance : The weather resistance test was carried out by using an accelerated test (black panel temperature: 83 ° C., 1,500 hours) using a sunshine carbon arc tester (manufactured by Suga Test Machine).
The surface appearance was observed at a magnification of 50 times, and the state of deterioration was determined based on the following criteria. A: There is no discoloration, no fading, and no crack. B: Discoloration, fading, or cracks are slightly observed. C: Discoloration, fading or cracks clearly occur and are visually observed. The interior material is required to have a weather resistance A level. Heat resistance : In the long-term heat resistance test, a 150 ° C. heating acceleration test was performed using a gear oven tester (manufactured by Toyo Seiki), and the time until embrittlement was measured. (Target: 500 hours or more) Glass haze : The glass haze test was performed by using a fogging tester (manufactured by Suga Test Instruments) to punch a disc having a diameter of 80 mm from a flat plate of 120 × 120 × 2 mm, and use this as a sample. Measure at 3. After heating and standing for 20 hours at an atmosphere temperature of 130 ° C. and a glass surface temperature of 40 ° C., the haze value of the glass surface was measured based on JIS-K7105. The haze value is required to be 5 or less for interior materials and lamps.

[II] Raw Materials The following raw materials were used in Examples and Comparative Examples. Component (A): ethylene / propylene block copolymer

[0022]

[Table 1]

Component (B): Inorganic filler Talc: Crown talc, a polypropylene resin having an average particle size of 6 μm (centrifugal sedimentation method) Component (C): Non-alkali metal salt of fatty acid

[0024]

[Table 2]

Component (D): N-methyl hindered amine stabilizer UV-1: N-methyl hindered amine stabilizer Adekastag LA-52 (manufactured by Asahi Denka Kogyo KK) UV-2: NH hindered amine stability Agent Tin
uvin622LD (manufactured by Ciba Specialty Chemicals) Component (E): hindered phenolic antioxidant AO-1: IRGANOX 1010FP (manufactured by Ciba Specialty Chemicals), melting point 117-120 ° C., AO-2: IRGANOX 3114 (Ciba) AO-3: IRGANOX 1076 (manufactured by Ciba Specialty Chemicals), melting point 50-53 ° C, melting point 218-223 ° C,

Thioether antioxidant AS-1: IRGAFOS12 (manufactured by Ciba Specialty Chemicals), molecular weight 1465, melting point 205 ° C., AS-2: Seanox 412S (manufactured by Cipro Kasei)
Molecular weight 1,162 Melting point 49-52 ° C AS-3: Sumilizer TPS (manufactured by Sumitomo Chemical Co., Ltd.) Molecular weight 683 Melting point 61-64 ° C

[III] Experimental Examples Examples 1 to 9 and Comparative Examples 1 to 13 The above-mentioned raw materials were blended in the proportions shown in Tables 3 to 6 and melt-kneaded. evaluated. The results are shown in Tables 3 to 6. The kneading is performed by a twin-screw kneader, and the ethylene-propylene block copolymer and the talc and necessary additives which are weighed and mixed from the hopper are charged and uniformly kneaded, and then extruded into strands.
After cooling, it was cut into pellets. Injection molding is JIS
A test piece and a 120 × 120 × 2 mm flat plate were formed and used for each evaluation.

[0028]

[Table 3]

[0029]

[Table 4]

[0030]

[Table 5]

[0031]

[Table 6]

[0032]

The inorganic filler-reinforced polyolefin-based resin composition of the present invention has excellent mechanical strength such as rigidity, heat resistance and impact strength, and excellent moldability such as injection molding.
Furthermore, since it has excellent weather resistance and long-term heat resistance and has extremely low occurrence of the glass haze phenomenon, it can be processed into various molded products such as automobile parts, home electric appliance parts, OA equipment parts, and housing building material parts. Among them, it can be used for automotive parts applications, for example, automotive interior parts such as instrument panels, door trims, pillar trims, console boxes, etc., and lamp housing materials such as head lamp housings, rear lamp housings, and high mount stop lamp housings. It is a very industrially useful material.

Claims (2)

[Claims] 1. An inorganic filler-reinforced polyolefin resin composition comprising the following components (A) to (E). Component (A: a propylene homopolymer portion having a density of 0.906 g / cm ³ or more and a weight average molecular weight of less than 140,000, a weight average molecular weight of 450,000 or more, and a proportion of less than 20% by weight in the block copolymer 95 to 50% by weight of an ethylene / propylene block copolymer composed of an ethylene / propylene random copolymerized component and Component (B): 5 to 50% by weight of an inorganic filler Component (C): a weight average molecular weight of 600 or more and a melting point of 110 ° C Non-alkali metal salt of the above fatty acid 0.1 to 5 parts by weight based on 100 parts by weight of inorganic filler Component (D): N-methyl hindered amine stabilizer 100 parts by weight in total of component (A) and component (B) Component (E): hindered phenolic antioxidant having a melting point of 110 ° C. or more, total of component (A) and component (B) 100 0.01 to 1 part by weight relative to the quantity unit 2. The antioxidant according to claim 1, wherein the hindered phenol-based antioxidant and a thioether-based antioxidant are used in combination, and the thioether-based antioxidant has a molecular weight of 1,000 or more. Inorganic filler reinforced polyolefin resin composition.