JP5443063B2 - Polypropylene resin composition and molded article for automobile interior parts - Google Patents

Description

  The present invention relates to a polypropylene-based resin composition that has excellent antistatic properties and can be molded into an automotive interior part that does not cause white turbidity due to bleed-out from the inside of the product in a use environment under a hot weather in summer. The present invention relates to a molded body for automobile interior parts obtained from a product.

  In recent years, polypropylene resin compositions have been widely used as materials for automobile interior parts. A molded product formed by injection molding of the resin composition can be supplied at a low cost and at a low cost, and the molded product can be provided with rigidity, heat resistance, and resistance by a material composition by blending other resins, elastomers, inorganic fillers, and the like. It is extremely useful because it can impart impact properties. An antistatic agent is often added to prevent dust from adsorbing to interior parts due to static electricity, but the temperature inside the car is locally about 80 to 90 ° C or higher under conditions such as under the hot summer heat. May rise. Even if the temperature does not rise to 90 ° C., there is a problem that white turbidity due to bleeding out of the antistatic agent on the surface of the molded article in a temperature environment of 50 to 70 ° C. becomes noticeable and visually deteriorates the appearance. there were. For example, Japanese Patent Application Laid-Open No. 11-349778 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2003-82169 (Patent Document 2) propose that a specific antistatic agent is blended. Although it has been shown that it can be suppressed, white turbidity is conspicuous in a temperature environment of 50 to 70 ° C. that is 10 to 20 ° C. lower than the melting point (70 to 80 ° C.) of the antistatic agent used therein, leading to the solution of the problem Not in.

JP 11-349778 A JP 2003-82169 A

  The present invention provides a polypropylene resin composition that is excellent in antistatic properties and that does not cause white turbidity due to bleed-out from the inside of the product even in the use environment under the hot weather in summer, and a composition thereof. An object of the present invention is to provide a molded body for automobile interior parts.

The present inventors have solved the above problems by developing a polypropylene resin composition containing a specific amount of stearyl diethanolamine monostearate as an antistatic agent.
That is, this invention provides the following polypropylene resin composition and the molded object for motor vehicle interior parts.

1. A polypropylene-based polymer as a main component, containing 0.2 to 1.5% by mass of stearyl diethanolamine monostearate based on the total amount of the composition, and melt flow rate (MFR) (JIS K-7210: temperature 230 ° C., A polypropylene resin composition having a load of 2.16 Kgf) of 5 to 150 g / 10 min.
2. 2. The polypropylene resin composition according to item 1 above, which contains up to 40% by mass of another polymer in addition to the polypropylene polymer.
3. 3. The polypropylene resin composition according to item 2, wherein the other polymer is selected from polyethylene and a copolymer of ethylene and α-olefin.
4). Furthermore, the polypropylene resin composition in any one of the preceding clauses 1-3 which contains an inorganic filler to 30 mass%.
5. The molded object for automotive interior parts obtained by injection-molding the resin composition in any one of the preceding clauses 1-4.
6). 6. The molded body for automotive interior parts according to item 5 above, wherein the molded body for automotive interior parts is an instrument panel, package tray, rear tray, pillar garnish, door trim or console box.

  The automotive interior parts obtained by molding the polypropylene resin composition of the present invention have excellent antistatic properties, and can be used to bleed out the antistatic agent from inside the product even under long-term weather conditions in midsummer. The resulting white turbidity does not occur, a good appearance can be maintained, and it is suitable as an automobile interior member.

Hereinafter, the present invention will be described in detail.
(A) Polypropylene resin In the polypropylene resin composition of the present invention, a polypropylene polymer having a melt flow rate (MFR) of 5 to 150 g / 10 min is used as the main component of the resin.
The polypropylene polymer used in the present invention may have a melt flow rate (MFR) of 5 to 150 g / 10 minutes measured at a temperature of 230 ° C. and a load of 2.16 Kgf according to JIS K-7210.

  The polypropylene polymer used as the main component of the resin in the present invention may be a propylene homopolymer, a block copolymer, or a random copolymer, or a combination of two or more of these. As the copolymer of these block copolymers and random copolymers, α-olefins other than propylene such as ethylene, butene-1, pentene-1, and hexene-1 are used. Of these, ethylene and butene- 1 is preferred.

In the present invention, only the above polypropylene-based polymer may be used, but other polymers may be used together with these polypropylene-based polymers. Other polymers include polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-pentene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, propylene-butene copolymer. , Propylene-hexene copolymers, propylene-octene copolymers, butene-hexene copolymers, butene-octene copolymers, α-olefin copolymers such as hexene-octene copolymers, and the like.
The blending amount of the other polymer is usually up to 40% by mass, preferably up to 30% by mass.

In addition, when manufacturing these polypropylene-based resins, or in each process from the production of polypropylene-based resins to the production of molded products for automobile interior parts, depending on the purpose of use, as long as the effects of the present invention are not significantly impaired. Styrene graft polymers of poly-4-methyl-1-pentene, polystyrene, polybutadiene or polyisoprene and copolymer elastomers obtained by hydrogenation of these, polymers such as polyester, polyamide, polycarbonate, etc. Also good.
The amount of these high molecular weight polymers is usually up to 5% by mass, preferably up to 3% by mass.

(B) Antistatic agent The present inventors have investigated various surfactants having a lipophilic part and a hydrophilic part as a molecular structure dispersed in a polypropylene resin composition and having an antistatic action. Stearyl diethanolamine monostearate (hereinafter referred to as an antistatic agent according to the present invention) is 0.2 to 1.5% by mass, preferably 0.2 to 1.0% by mass, and more preferably 0.2 to 0. Automobile interior that does not cause white turbidity due to bleed-out inside the product when used in a car environment under the hot summer sun when the polypropylene resin composition containing 5% by mass is excellent in antistatic properties and is used as a molded product Confirmed to give parts.

  When the blending amount of the antistatic agent according to the present invention in the polypropylene resin composition is less than 0.2% by mass, the antistatic effect is not sufficiently exhibited, and the blending amount exceeds 1.5% by mass. In this case, bleeding out of the antistatic agent occurs, and the effect of the present invention is not recognized.

(C) Inorganic filler The polypropylene resin composition of the present invention may contain an inorganic filler for the purpose of improving rigidity and heat resistance. Examples of the inorganic filler include talc, mica, calcium carbonate, glass fiber, silica, calcium silicate, magnesium sulfate, barium sulfate, and potassium titanate. Among these, talc, mica, calcium carbonate, and glass fiber are preferable from the viewpoint of moldability, rigidity-impact resistance, and talc is particularly preferable.
The content of the inorganic filler in the polypropylene resin composition of the present invention is preferably up to 30% by mass and more preferably up to 25% by mass in the polypropylene resin composition.

(D) Other components The polypropylene resin composition of the present invention is within the range that does not significantly impair the effects of the present invention, in addition to the polypropylene polymer, other polymers or elastomers, antistatic agents, and inorganic fillers. Depending on the purpose of use, additives such as heat, oxygen, and light stabilizers, weathering agents, crystal nucleating agents, lubricants, flame retardants, and plasticizers, which are widely used in the field of synthetic resins and synthetic rubbers, are added. May be.
In the present invention, a pigment may be further blended with a polypropylene resin in which these stabilizers or various additives are blended.

Stabilizers for heat and oxygen include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, etc.
Examples of weathering agents for preventing deterioration by light include amine compounds, triazole compounds, benzophenone compounds, benzoate compounds, nickel compounds, salicylic acid compounds,
Examples of the crystal nucleating agent include sorbitol-based, phosphorus-based, rosin-based, organophosphate metal salt, carboxylic acid metal salt, and the like.
Examples of lubricants include fatty acid amides, higher alcohols, polyethylene waxes,
Examples of flame retardants include phosphate, melamine, phosphorus, halogen, and non-halogen compounds,
Examples of the plasticizer include phthalate-based, fatty acid-based, adipate-based, trimellitate-based, epoxy-based, and polyester-based compounds.

  Examples of the pigment include inorganic pigments and organic pigments. As for the inorganic pigment, the coloring portion is an inorganic substance, and the element is composed of a single element, and oxides such as Zn, Pb, Ti, Sb, Cd, Fe, As, Mg, Al, Co, Cr, sulfide, sulfate, etc. Is mentioned. The organic pigment has an organic compound in the coloring portion, and examples thereof include azo pigments, polyazo pigments, acetylene pigments, copper phthalocyanine pigments, dioxane pigments, and quinacridone pigments. For the purpose of improving the dispersibility of the pigment in polypropylene, a dispersion aid (including fatty acid metal salts, naphthenic acid metal salts, surfactants, silicone oil, lecithin and the like) may be used.

  When the polypropylene resin composition of the present invention is formed into a molded body, it can be produced by blending the main component polypropylene polymer with the antistatic agent according to the present invention by a conventional method. You may mix | blend a polymer, an inorganic filler, a pigment, and another additive. For example, powder-type and pellet-type polypropylene polymers and other polymers are blended with the antistatic agent according to the present invention, and if necessary, inorganic fillers, pigments and other additives, and are mixed with a Henschel mixer, a tumbler mixer, etc. After mixing, the mixture is melt-kneaded and pelletized with a uniaxial or biaxial kneading extruder. The pellets thus obtained are processed into a molded body using an injection molding machine. If the MFR of the polypropylene-based resin composition is less than 5 g / 10 minutes, the moldability in injection molding is poor, and it is not suitable as an automotive interior part application. Moreover, when exceeding 150 g / 10min, it is inferior to impact resistance and is not suitable as a use for automobile interior parts.

[Molded body for automotive interior parts]
The molded body for automobile interior parts of the present invention can be produced by injection molding the above polypropylene resin composition.
The molding temperature is generally 150 to 350 ° C, preferably 170 to 250 ° C. When the molding temperature exceeds 350 ° C., it causes deterioration of the resin composition and molding defects, and when it is lower than 150 ° C., appearance defects and molding defects occur. About mold temperature, it is preferable to carry out in the range of 10-60 degreeC. When the mold temperature exceeds 60 ° C., the surface finish of the molded body is excellent and a molded body having excellent rigidity can be obtained, but the molding cycle becomes long and the productivity is lowered. Conversely, if the mold temperature is set to a temperature lower than 10 ° C., warpage, shrinkage, etc. become prominent, and it becomes difficult to obtain a satisfactory molded product, and mold corrosion tends to occur because it tends to cause condensation on the mold. Cause it. It is not suitable from the viewpoint of energy costs related to cooling.

  Parts for automobile interior parts obtained by molding the polypropylene resin composition of the present invention have the effect of preventing bleed-out of the antistatic agent even when exposed to high temperatures such as under hot weather in summer. For example, it is applied to molded parts for automobile interior parts that are generally manufactured by injection molding using polypropylene resin compositions such as instrument panels for passenger cars, package trays, rear trays, pillar garnishes, door trims, console boxes, etc. The effects of the present invention can be achieved.

  Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these examples.

Examples 1-14 and Comparative Examples 1-4:
[Polypropylene resin composition components]
In Examples and Comparative Examples, the following PP-1 to PP-12 were used as polypropylene resin composition components. In addition, the measurement of the melt flow rate (MFR) of each polypropylene resin composition was performed according to JIS K-7210, and was measured by 230 degreeC and the load 2.16Kgf.

PP-1: 2% by mass of an inorganic pigment (mixture of carbon black 30% by mass, titanium white 20% by mass, magnesium stearate 50% by mass) with respect to a homotype polypropylene (manufactured by Sun Allomer, PM900A) of MFR 30 g / 10 min. Mixed resin composition.

PP-2: MFR 30 g / 10 min, block type crystalline ethylene-propylene copolymer having a rubber component content of 20% by mass (manufactured by Sun Allomer, PM970A), inorganic pigment (carbon black 30% by mass, titanium white 20 A resin composition in which 2% by mass is mixed).

PP-3: MFR 43 g / 10 min, block type crystalline ethylene-propylene copolymer having a rubber component content of 22% by mass (manufactured by Sun Allomer, PMA80X), organic pigment (copper phthalocyanine blue 50% by mass, stearic acid) (Mixture of 50% by mass of magnesium) 3% by mass of a resin composition.

PP-4: A resin composition in which 10% by mass of MFR 2 g / 10 min ethylene-butene copolymer (Mitsui Chemicals, A-1050S) is mixed with PP-1.

PP-5: A resin composition obtained by mixing 30% by mass of an ethylene-butene copolymer (Mitsui Chemicals, A-1050S) with an MFR of 2 g / 10 min with PP-1.

PP-6: A resin composition in which 30% by mass of an ethylene-octene copolymer (manufactured by Dow Chemical Co., Ltd., ENGAGE 8200) of MFR 10 g / 10 min is mixed with PP-1.

PP-7: A resin composition in which 10% by mass of talc (Hayashi Kasei Co., Ltd., 5000S) is mixed with PP-5.

PP-8: A resin composition in which 30% by mass of talc (manufactured by Hayashi Kasei Co., Ltd., 5000S) is mixed with PP-5.

PP-9: A resin composition obtained by mixing 10% by mass of talc (manufactured by Hayashi Kasei Co., Ltd., 5000S) with PP-6.

PP-10: A resin composition obtained by mixing 30% by mass of talc (manufactured by Hayashi Kasei Co., Ltd., 5000S) with PP-6.

PP-11: MFR 7 g / 10 min, block type crystalline ethylene-propylene copolymer having a rubber component content of 21.5 mass% (manufactured by Sun Allomer, PM671A), inorganic pigment (carbon black 30 mass%, titanium) A mixture of 20% by weight of white and 50% by weight of magnesium stearate) 2% by weight.

PP-12: MFR 110 g / 10 min, rubber component content 18.5% by mass of block type crystalline ethylene-propylene copolymer (Sun Allomer, PMD81M), inorganic pigment (carbon black 30% by mass, titanium A mixture of 20% by weight of white and 50% by weight of magnesium stearate) 2% by weight.

[Antistatic agent]
In Examples 1 to 14 and Comparative Examples 3 to 4, stearyl diethanolamine monostearate (manufactured by Kao Corporation, Electro Stripper TS-6B) was used as an antistatic agent.
In Comparative Examples 1 and 2, glycerin monostearate (manufactured by Kao Corporation, Electro Stripper TS-5) was used as an antistatic agent.

[Sample preparation]
An antistatic agent composed of stearyldiethanolamine monostearate was added in an amount shown in Table 1 to 100 parts by mass of the polypropylene-based resins of PP-1 to PP-12, and dry blended. The obtained mixture was extruded using a KTX-30 same-direction twin screw extruder manufactured by Kobe Steel Co., Ltd. at an extrusion set temperature of 180 ° C. and an extrusion screw rotation speed of 300 rpm, to produce pellets. Furthermore, using this pellet, a 130 × 130 × 2 mmt flat plate was injection-molded under the conditions of a cylinder setting temperature of 220 ° C. and a mold setting temperature of 40 ° C. using a FANUC α100C injection molding machine to obtain a test piece. The test pieces were stored for 24 hours or more in a room controlled at a temperature of 23 ± 2 ° C. and a relative temperature of 50 ± 5%, and then subjected to the test.

[Evaluation of antistatic properties]
After storing the test piece in a room controlled at a temperature of 23 ± 2 ° C. and a relative temperature of 50 ± 5% for one week or more, a voltage of 1000 V was applied for 1 minute with an electric resistance measuring instrument (Hewlett Packard 4329A High Resistance Meter), After turning off the applied voltage, the surface resistivity was measured. The measurement results are shown in Table 1.

[Bleed evaluation]
The test piece was placed in an oven set at 60 ° C. for 200 hours and taken out, and then the appearance was visually observed and evaluated according to the following criteria.
○: Bleed is not observed visually.
Δ: Bleed is observed visually.
X: Bleed is easily observed visually and cannot be used practically.
Table 1 shows the observation results of the bleeding property of each test piece.

  A molded body obtained by injection molding a resin composition obtained by blending PP-1 in an amount of 0.2% by mass with an antistatic agent composed of stearyl diethanolamine monostearate with respect to 100% by mass (Example) As for 1), the result of the bleed test was good.

  It was obtained by injection-molding a resin composition obtained by changing the blending ratio of the antistatic agent composed of stearyl diethanolamine monostearate and the type of polypropylene resin in Example 1 with respect to Example 1. Also about the molded object (Examples 2-14), the bleed test result was favorable in all cases.

  In contrast to Example 1, Comparative Example 1 using an antistatic agent made of glycerin monostearate instead of stearyl diethanolamine monostearate had a poor bleed test result. Further, in Comparative Example 2, glycerin monostearate was halved, but although the result of the bleed test was improved from x to Δ, the surface resistivity increased and the antistatic effect deteriorated.

  Compared to Example 1, an antistatic agent comprising stearyl diethanolamine monostearate had a poor bleed test result in Comparative Example 3 exceeding 1.5% by mass of the claimed range, and was reduced to 0.2% by mass of the claimed range. In Comparative Example 4 which is not satisfied, the surface specific resistance was increased and the antistatic effect was deteriorated.

Claims (5)

A polypropylene resin composition for automotive interior parts that contains only stearyl diethanolamine monostearate as an antistatic agent, comprising a polypropylene polymer as a main component, and stearyl diethanolamine monostearate in an amount of 0. Polypropylene resin composition for automotive interior parts containing 2 to 1.5 mass% and having a melt flow rate (MFR) (measured at JIS K-7210: temperature 230 ° C., load 2.16 Kgf) of 5 to 150 g / 10 min. object.   The automobile interior according to claim 1, comprising, in addition to the polypropylene polymer, up to 40% by mass of one or more polymers selected from polyethylene and a copolymer of ethylene and α-olefin as another polymer. Polypropylene resin composition for parts.   Furthermore, the polypropylene-type resin composition for motor vehicle interior components of Claim 1 or 2 containing an inorganic filler to 30 mass%.   The molded object for automotive interior parts obtained by injection-molding the resin composition in any one of Claims 1-3.   The molded body for automotive interior parts according to claim 4, wherein the molded body for automotive interior parts is an instrument panel, a package tray, a rear tray, a pillar garnish, a door trim or a console box.