JP6302201B2 - Resin composition and use thereof - Google Patents

Description

  The present invention relates to a resin composition and a molded product formed by using the resin composition.

When manufacturing automotive interior materials such as instrument panels, door panels, seat backs, pillars, steering wheels, and large, complex sheet-shaped resin moldings, the molding surface of the heated mold is thermoplastic. A so-called powder slush molding method is widely practiced in which resin powder is adhered and melted and then cooled to take out a resin molded product.
In the powder slush molding method, in order to reduce the weight of the obtained thermoplastic resin molding, there is a method in which a thermoplastic resin is blended with a pyrolytic foaming agent (see Patent Document 1). However, many fine holes (so-called pinholes) are generated on the surface by the foaming gas generated by the decomposition of the foaming agent. For this reason, it was difficult to use for a product with high designability. Also, it is difficult to control the size of the bubbles due to the foaming gas. As a result, the physical properties of the obtained molded product are affected, which is a problem.

  On the other hand, if thermally expandable microspheres are used as the foaming component instead of the pyrolytic foaming agent, closed cells can be introduced into the resulting molded product. Furthermore, by adjusting the heating temperature at the time of molding, it is possible to easily control the size of bubbles and the specific gravity of the molded product, and therefore, application to a powder slush molding method has been proposed (see Patent Document 2). However, the obtained molded product was inferior in surface properties. That is, not only the surface of the molded product in contact with the mold but also the back surface of the molded product was inferior in surface properties. Therefore, not only the appearance of the surface of the molded product is not good, but also the back surface is inferior in surface properties, so there is a problem that it is difficult to sufficiently bond other members to the back surface. Improvement in surface properties has been desired.

International Publication No. 2009/084175 JP 11-322998 A

  An object of the present invention is to provide a resin composition that is excellent in surface properties on both the front and back surfaces by powder slush molding, and can obtain a lightweight molded product.

As a result of intensive studies for solving the above problems, the present inventors have obtained the knowledge that the above problems can be solved by using, for example, hollow particles having a specific true specific gravity, and reached the present invention. did.
The resin composition of the present invention is a resin composition used in powder slush molding, and includes thermoplastic resin powder and hollow particles whose outer shell portion is made of a thermoplastic resin, and the true specific gravity of the hollow particles is 0.00. The average particle size is 0.8 to 60 μm, and the hollow particles are 1 to 20 parts by weight with respect to 100 parts by weight of the thermoplastic resin powder.

The true specific gravity of the hollow particles is preferably 0.02 to 0.15 g / cc. It is preferable that fine particles adhere to the outer surface of the outer shell portion.
The method for producing a molded product of the present invention is obtained by powder slush molding the above resin composition. This molded article may have a true specific gravity of 1.1 g / cc or less.

The resin composition of the present invention can obtain a molded product having excellent surface properties on both the front and back surfaces by powder slush molding.
The molded product of the present invention is excellent in surface properties on both the front surface and the back surface.

It is an example of sectional drawing of the hollow particle (microparticle-adhered hollow particle) which microparticles | fine-particles adhered to the outer surface. It is explanatory drawing of the outline | summary of powder slush molding.

(Resin composition)
The resin composition of the present invention is a resin composition used in powder slush molding, and essentially comprises a thermoplastic resin powder and hollow particles. This resin composition may further contain other components other than the thermoplastic resin powder and the hollow particles.
Hereinafter, each component which comprises a resin composition is demonstrated.

(Thermoplastic resin powder)
The thermoplastic resin powder is a powder made of a thermoplastic resin having such a property that it can be molded by heating, that is, has a property of causing plastic deformation when heated and reversibly curing when cooled.
The thermoplastic resin constituting the thermoplastic resin powder is not particularly limited. For example, polyolefin resin (PO), polyvinyl chloride resin (PVC), polystyrene resin (PS), polyurethane resin (PU). , Acrylic resins, polyamide resins, polyester resins, thermoplastic elastomers (TPE), and other resins. These thermoplastic resins may be used alone or in combination of two or more.

Examples of the polyolefin resin (PO) include ethylene, propylene, 1-butene, 4-methyl-1-pentene, 3-methyl-1-butene, 1-pentene, 1-hexene, 1-octene and 1-decene. , A polymer obtained by homopolymerization or copolymerization of olefins such as 1-dodecene, 1-hexadecene, 1-octadecene and 1-eicosene and diolefins such as butadiene and isoprene (this polymer contains an unsaturated bond) And may be a hydrogenated polymer)); monomers such as the above olefins and / or diolefins and vinyl acetate, acrylic acid, acrylic ester, methacrylic acid, methacrylic ester, vinyl alcohol, maleic acid, etc. And a copolymer thereof.
Examples of the polyvinyl chloride resin (PVC) include polyvinyl chloride, chlorinated polyvinyl chloride, polyvinylidene chloride, vinyl chloride / vinyl acetate copolymer, vinyl chloride / ethylene copolymer, vinyl chloride / ethylene / acetic acid. A vinyl copolymer etc. can be mentioned.

Examples of the polystyrene resin (PS) include polystyrene, styrene / ethylene copolymer, styrene / propylene copolymer, styrene / ethylene / propylene copolymer, styrene / isoprene copolymer, styrene / butadiene copolymer, Styrene / isoprene / butadiene copolymer, styrene / maleic acid derivative copolymer, styrene / acrylonitrile copolymer, acrylonitrile / butadiene / styrene copolymer, acrylonitrile / acrylic ester / styrene copolymer, methyl methacrylate / butadiene / Styrene copolymer and the like (when this polymer contains an unsaturated bond, it may be a hydrogenated polymer).
Polyurethane resin (PU) can be obtained by a known method, for example, a method of polymerizing an organic diisocyanate and a dihydroxy compound. This polymerization may be performed in the presence of a dispersant, a solvent or the like.

Examples of the organic diisocyanate include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, xylene diisocyanate, cyclohexane diisocyanate, toluidine diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, Examples thereof include p-phenylene diisocyanate, m-phenylene diisocyanate, 1,5-naphthylene diisocyanate and the like. These organic diisocyanates may be used alone or in combination of two or more.
Examples of the dihydroxy compound include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 2,3-butylene glycol, 1,4-butanediol, and 2,2′-dimethyl-1,3-propane. Examples include diol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, polyester diol, polyether diol, and polycarbonate diol. These dihydroxy compounds may be used alone or in combination of two or more.

Although it does not specifically limit as acrylic resin, For example, the (co) polymer obtained by superposing | polymerizing acrylic monomers, such as (meth) acrylic acid and (meth) acrylic acid ester, is mentioned. As the (meth) acrylic acid ester, a (meth) acrylic acid alkyl ester or a (meth) acrylic acid-substituted alkyl ester is preferable from the viewpoint of processability and flexibility.
Although there is no limitation in particular as an alkyl group of (meth) acrylic-acid alkylester, For example, a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, n-pentyl group, n-hexyl Group, cyclohexyl group, 2-ethylhexyl group, isobornyl group, stearyl group and the like.

The substituted alkyl group of (meth) acrylic acid-substituted alkyl is not particularly limited. For example, an alkyl group substituted with a hydroxyl group such as 2-hydroxyethyl group or 2-hydroxypropyl group; an epoxy group such as glycidyl group is substituted. Alkyl groups substituted with amino groups such as 2-aminoethyl group; trifluoromethylmethyl group, 2-trifluoromethylethyl group, 2-perfluoroethylethyl group, 2-perfluoroethyl-2-par Fluorobutylethyl group, 2-perfluoroethyl group, perfluoromethyl group, diperfluoromethylmethyl group, 2-perfluoromethyl-2-perfluoroethylmethyl group, 2-perfluorohexylethyl group, 2-perfluoro Halo such as decylethyl group, 2-perfluorohexadecylethyl group, etc. Emissions atom (preferably fluorine atom) can be exemplified an alkyl group which has been substituted.
The acrylic resin may be a polymer obtained by copolymerizing an acrylic monomer that is a raw material of the resin specifically exemplified above and other monomers (unsaturated bond is present in this polymer). If included, it may be a hydrogenated polymer). Such other monomers include styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, acrylonitrile, methacrylonitrile, butadiene, isoprene, vinyl chloride, vinylidene chloride, perfluoroethylene, perfluoro. Propylene, vinylidene fluoride, vinyltrimethoxysilane, vinyltriethoxysilane, maleic anhydride, maleic acid, monoalkyl and dialkyl esters of maleic acid, fumaric acid, monoalkyl esters of fumaric acid, vinyl acetate, vinyl propionate, Vinyl pivalate, vinyl benzoate, vinyl cinnamate, maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide, dodecylmaleimide, Stearyl maleimide, phenyl maleimide and cyclohexyl maleimide.

The polyamide resin is a crystalline resin that forms a main chain by repeating acid amide bonds (—CONH—). For example, 6-nylon, 66-nylon, 6,10-nylon, 6,12-nylon, 11- Examples thereof include modified nylons such as nylon, 12-nylon, 46-nylon, MXD-nylon, 6-T nylon and the like.
Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polycyclohexylene dimethylene terephthalate, and the like.

Examples of the thermoplastic elastomer (TPE) include urethane (TPU), vinyl chloride, olefin (TPO), styrene (TPS), fluorine, polyamide, and polyester thermoplastic elastomers. .
Examples of other resins include polyoxymethylene, polycarbonate, and modified polyphenylene ether.

These thermoplastic resins may be partially crosslinked by a known method of dynamically heat-treating in the presence of an organic peroxide or the like. Examples of the organic peroxide used for partial crosslinking include benzoyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, 2,5-dimethyl-2, Examples include 5-di (t-butylperoxy) hexane, dicumyl peroxide, t-butylhydroxyperoxide, and the like. Further, a crosslinking aid for promoting crosslinking may be used in combination with the organic peroxide, such as triallyl cyanurate, triallyl isocyanurate, trimethylolpropane trimethacrylate, 1,2-polybutadiene, divinylbenzene and the like. be able to.
When the thermoplastic resin is a copolymer, the structure may be any of a random structure, a block structure, a graft structure, etc., or a mixture thereof.

Moreover, the thermoplastic resin used for the thermoplastic resin powder may further contain other components blended in the resin composition described below.
The average particle diameter of the thermoplastic resin powder is not particularly limited, but is preferably 1 to 2000 μm, more preferably 5 to 1000 μm, still more preferably 10 to 700 μm, particularly preferably 30 to 500 μm, and most preferably 50 to 300 μm. When the average particle size of the thermoplastic resin powder is less than 1 μm, not only the workability is deteriorated due to dust generation but also the powder is likely to be blocked, and the molding may be difficult. On the other hand, when the average particle diameter of the thermoplastic resin powder exceeds 2000 μm, it becomes difficult to uniformly adhere to the mold surface used for molding, and as a result, the surface properties of the surface and the back surface of the resulting molded product May decrease.

The method for preparing the thermoplastic resin powder is not particularly limited. For example, a method of obtaining a powder from a thermoplastic resin production plant; a method of obtaining a powder by pulverizing a pelletized thermoplastic resin; Examples thereof include a method in which several kinds of thermoplastic resins and the like are melt-kneaded with a kneader to form pellets, and then the resulting thermoplastic resin pellets are pulverized to form powder.
In particular, as a method for preparing the thermoplastic resin powder from the pellets of the thermoplastic resin, for example, the pellets of the thermoplastic resin are frozen at −50 to −100 ° C. with liquid nitrogen, dry ice or the like and mechanically processed by a pulverizer. A freezing and pulverizing method in which the pellets of thermoplastic resin are pulverized mechanically by a pulverizer at room temperature while removing frictional heat with a large amount of air flow or without cooling means; Examples thereof include a chemical pulverization method in which a pellet of a thermoplastic resin is dissolved in a solvent at a high temperature and cooled and precipitated by using a difference in solubility depending on temperature, or precipitated by adding a poor solvent to the solution.

(Hollow particles)
Hollow particles are a component that reduces the weight of a molded product obtained by powder slush molding of the resin composition of the present invention. By containing hollow particles in the resin composition of the present invention, the surface property is excellent on both the front surface and the back surface of the molded product, the texture (surface pattern) transferability is good, and the molded product is excellent in design. Also, since the hollow particles are already light, they can be easily adjusted to the specific gravity intended for the molded product.
The hollow particles, which are composed of an outer shell portion and a hollow portion surrounded by the outer shell portion, are (substantially) spherical and have a hollow portion corresponding to a large cavity inside. If the shape of the hollow particles is exemplified by familiar articles, a soft tennis ball can be mentioned.

The average particle diameter of the hollow particles is not particularly limited because it can be designed freely according to the use, but is preferably 0.01 to 1000 μm, more preferably 0.1 to 800 μm, and still more preferably 0.8 to 200 μm. Further, the coefficient of variation CV of the particle size distribution of the hollow particles is not particularly limited, but is preferably 30% or less, and more preferably 25% or less.
The true specific gravity of the hollow particles is not particularly limited, but is usually 0.02 to 0.3 g / cc, preferably 0.03 to 0.25 g / cc, more preferably 0.04 to 0.20 g / cc, Preferably it is 0.05-0.15 g / cc, Most preferably, it is 0.06-0.10 g / cc. When the true specific gravity of the hollow particles is less than 0.02 g / cc, the surface properties of both the surface and the back surface of the obtained molded product are deteriorated, the molded product becomes brittle, and the mechanical properties may be reduced. . On the other hand, if the true specific gravity of the hollow particles exceeds 0.3 g / cc, the molded product may not be sufficiently lightened. Therefore, it is necessary to increase the amount of hollow particles blended in the resin composition, which may be disadvantageous economically.

Although there is no limitation in particular about the kind of hollow particle, The particle | grains in which the outer shell part is comprised from an inorganic component, the particle | grains in which the outer shell part is comprised from a thermoplastic resin, etc. can be mentioned. Hereinafter, in order to avoid confusion with the “thermoplastic resin” of the thermoplastic resin powder described above, the thermoplastic resin constituting the outer shell portion may be referred to as “thermoplastic resin A”.
Examples of the particles composed of inorganic components include glass balloons, shirasu balloons, fly ash, silica balloons and the like. On the other hand, as the particles composed of the thermoplastic resin A, heat-expandable microspheres composed of an outer shell composed of the thermoplastic resin A and a foaming agent encapsulated therein and vaporized by heating are expanded. And particles obtained from the above.

The hollow particles obtained by heating and expanding the heat-expandable microspheres mentioned in the latter are not particularly limited, and there are methods for heating and expanding the heat-expandable microspheres described below. Examples of the heating expansion method include a dry heating expansion method and a wet heating expansion method. The temperature for heat expansion is preferably 80 to 350 ° C.
As shown in FIG. 1, the hollow particles (1) may be composed of fine particles (4 and 5) attached to the outer surface of the outer shell (2). There is.

The term “adhesion” as used herein may be simply the state (4) in which the fine particle fillers (4 and 5) are adsorbed on the outer surface of the outer shell (2) of the fine particle-adhered hollow particles (1). This means that the thermoplastic resin constituting the outer shell in the vicinity may be melted by heating, and the fine particle filler may sink into the outer surface of the outer shell of the fine particle-attached hollow particle and be fixed (5). The particle shape of the fine particle filler may be indefinite or spherical. In the fine particle-adhered hollow particles, workability (handling) during use is improved.
The average particle diameter of the fine particles adhering to the outer surface is preferably 1/4 to 1/10 of the average particle diameter of the hollow particles.

The average particle diameter of the fine particles is preferably 0.001 to 30 μm, more preferably 0.005 to 25 μm, and particularly preferably 0.01 to 20 μm. Within this range, the mixability with the thermally expandable microspheres is good when producing hollow particles. The average particle diameter of the fine particles referred to here is the particle diameter of the particles measured by a laser diffraction method. If the particle size of the fine particles is on the order of micron, it indicates primary particles, but nano-order fine particles are often agglomerated and act as aggregates in the order of micron, so the aggregated secondary particles are regarded as one unit. The average particle size was calculated.
Various particles can be used as the fine particles, and any of inorganic materials and organic materials may be used. Examples of the shape of the fine particles include a spherical shape, a needle shape, and a plate shape.

The fine particles are not particularly limited, but when the fine particles are organic, for example, metal soaps such as magnesium stearate, calcium stearate, zinc stearate, barium stearate, lithium stearate; polyethylene wax, lauric acid amide, myristic acid Synthetic waxes such as amide, palmitic acid amide, stearic acid amide, and hardened castor oil; and organic fillers such as polyacrylamide, polyimide, nylon, polymethyl methacrylate, polyethylene, and polytetrafluoroethylene. When the fine particles are inorganic, for example, talc, mica, bentonite, sericite, carbon black, molybdenum disulfide, tungsten disulfide, fluorinated graphite, calcium fluoride, boron nitride, etc .; others, silica, alumina, mica, colloidal Inorganic fillers such as calcium carbonate, heavy calcium carbonate, surface-treated calcium carbonate, calcium hydroxide, calcium phosphate, magnesium hydroxide, magnesium phosphate, barium sulfate, titanium dioxide, zinc oxide, ceramic beads, glass beads, crystal beads Is mentioned.
The true specific gravity of the fine particle-attached hollow particles is not particularly limited, but is usually 0.02 to 0.3 g / cc, preferably 0.03 to 0.25 g / cc, more preferably 0.04 to 0.20 g / cc. cc, more preferably 0.05 to 0.15 g / cc, particularly preferably 0.06 to 0.10 g / cc. When the true specific gravity of the fine particle-attached hollow particles is less than 0.02 g / cc, the durability may be insufficient. On the other hand, if the true specific gravity of the fine particle-adhered hollow particles is greater than 0.3 g / cc, the effect of lowering the specific gravity is reduced, so when preparing the composition using the fine particle-adhered hollow particles, the amount added is increased, May be uneconomical.

The fine particle-attached hollow particles can be obtained, for example, by heating and expanding fine particle-attached thermally expandable microspheres. As a method for producing fine particle-attached hollow particles, a step of mixing thermally expandable microspheres and fine particles (mixing step), and heating the mixture obtained in the mixing step to a temperature above the softening point, the heat A production method including a step (attachment step) of inflating the expandable microspheres and attaching fine particles to the outer surface of the obtained hollow particles is preferable.
The thermally expandable microsphere is composed of an outer shell made of the thermoplastic resin A and a foaming agent that is encapsulated in the shell and vaporizes when heated, and the thermally expandable microsphere is thermally expandable as a whole microsphere ( The property that the whole microsphere expands by heating). In the following description, the inclusion substance and the foaming agent may be used synonymously.

The average particle size of the heat-expandable microspheres is not particularly limited, but is preferably 1 to 100 μm, more preferably 3 to 80 μm, still more preferably 7 to 60 μm, and particularly preferably 10 to 50 μm. When the average particle diameter is smaller than 1 μm, the expansion performance of the thermally expandable microspheres is lowered, and the weight reduction effect may be lowered. On the other hand, when the average particle diameter is larger than 100 μm, the average diameter of closed cells due to the hollow particles is increased, and the surface property may be deteriorated on both the front surface and the back surface of the molded product.
The foaming agent constituting the thermally expandable microsphere is not particularly limited as long as it is a substance that is vaporized by heating. Examples of the blowing agent include propane, (iso) butane, (iso) pentane, (iso) hexane, (iso) heptane, (iso) octane, (iso) nonane, (iso) decane, (iso) undecane, ( Hydrocarbons having 3 to 13 carbon atoms such as iso) dodecane and (iso) tridecane; hydrocarbons having 13 to 20 carbon atoms such as (iso) hexadecane and (iso) eicosane; pseudocumene, petroleum ether, initial boiling point 150 Hydrocarbons such as petroleum fractions such as normal paraffin and isoparaffin having a distillation range of ˜260 ° C. and / or a distillation range of 70 to 360 ° C .; their halides; fluorine-containing compounds such as hydrofluoroethers; tetraalkylsilanes; The compound etc. which decompose | disassemble and produce | generate a gas can be mentioned. These foaming agents may be used alone or in combination of two or more. The foaming agent may be linear, branched or alicyclic, and is preferably aliphatic.

The encapsulating rate of the foaming agent encapsulated in the heat-expandable microspheres is not particularly limited, but is preferably 1 to 60% by weight, more preferably 3 to 50% by weight, based on the weight of the heat-expandable microspheres. Preferably it is 8 to 40 weight%, Most preferably, it is 10 to 30 weight%.
The thermoplastic resin A constituting the outer shell of the thermally expandable microsphere is a (suspension) polymerizable component including a monomer component which is a (radical) polymerizable monomer having one polymerizable double bond. It is a copolymer obtained by polymerization.

The polymerizable component is a component that becomes a copolymer that is the thermoplastic resin A that forms an outer shell by polymerization. The polymerizable component is a component which essentially includes a monomer component and may contain a crosslinking agent.
The monomer component is not particularly limited. For example, nitrile monomers such as acrylonitrile, methacrylonitrile, fumaronitrile, and maleonitrile; vinyl halide monomers such as vinyl chloride; halogenated compounds such as vinylidene chloride Vinylidene monomers; vinyl ester monomers such as vinyl acetate, vinyl propionate and vinyl butyrate; unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid and cinnamic acid, and maleic acid Unsaturated dicarboxylic acids such as itaconic acid, fumaric acid, citraconic acid, chloromaleic acid, anhydrides of unsaturated dicarboxylic acids, monomethyl maleate, monoethyl maleate, monobutyl maleate, monomethyl fumarate, monoethyl fumarate, Monomethyl itaconate, monoethyl itaconate, itaconate Carboxyl group-containing monomers such as unsaturated dicarboxylic acid monoesters such as butyl; methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl ( (Meth) acrylates such as (meth) acrylate, stearyl (meth) acrylate, phenyl (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate and 2-hydroxyethyl (meth) acrylate (Meth) acrylamide monomers such as acrylamide, substituted acrylamide, methacrylamide and substituted methacrylamide; maleimide monomers such as N-phenylmaleimide and N-cyclohexylmaleimide; Styrene monomers such as α-methylstyrene; ethylene unsaturated monoolefin monomers such as ethylene, propylene and isobutylene; vinyl ether monomers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl Examples thereof include vinyl ketone monomers such as methyl ketone; N-vinyl monomers such as N-vinyl carbazole and N-vinyl pyrrolidone; vinyl naphthalene salts and the like. In the carboxyl group-containing monomer, some or all of the carboxyl groups may be neutralized during polymerization or after polymerization. Acrylic acid or methacrylic acid may be collectively referred to as (meth) acrylic acid, and (meth) acryl means acrylic or methacrylic.

Among the nitrile monomers, acrylonitrile and / or methacrylonitrile are preferable.
Among the carboxyl group-containing monomers, acrylic acid, methacrylic acid, maleic acid, maleic anhydride and itaconic acid are preferable, acrylic acid and methacrylic acid are more preferable, and methacrylic acid is particularly preferable because of high heat resistance.

The monomer components include nitrile monomers, carboxyl group-containing monomers, (meth) acrylic acid ester monomers, styrene monomers, vinyl ester monomers, acrylamide monomers, and halogens. It is preferable to further include at least one selected from vinylidene chloride monomers.
Although it does not specifically limit as a crosslinking agent, For example, aromatic divinyl compounds, such as divinylbenzene; Allyl methacrylate, triacryl formal, triallyl isocyanate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1 , 4-butanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, PEG # 200 di (meth) acrylate, PEG # 600 di (meth) acrylate, trimethylolpropane trimethacrylate, pentaerythrul Examples include di (meth) acrylate compounds such as tall tri (meth) acrylate, dipentaerythritol hexaacrylate, and 2-butyl-2-ethyl-1,3-propanediol diacrylate. These crosslinking agents may be used alone or in combination of two or more.
The amount of the crosslinking agent is not particularly limited, but is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 1 part by weight, and particularly preferably 0. More than 2 parts by weight and less than 1 part by weight. The amount of the crosslinking agent may be less than 0.01 parts by weight with respect to 100 parts by weight of the monomer component.

(Other ingredients)
The other components are components that are appropriately blended in the resin composition together with the thermoplastic resin powder and the hollow particles. Examples of other components include plasticizers (softeners), flame retardants, antioxidants, colorants, fillers, mold release agents, antistatic agents, crystal nucleating agents, and the like.
Examples of plasticizers (softeners) include petroleum oils such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, and petroleum jelly; coal tars such as coal tar and coal tar pitch; castor oil, linseed oil, Fatty oils such as rapeseed oil, soybean oil, coconut oil; waxes such as tall oil, beeswax, carnauba wax, lanolin, fatty acids such as ricinoleic acid, palmitic acid, stearic acid or metal salts thereof; petroleum resin, coumarone indene resin Synthetic polymers such as atactic polypropylene; diallyl phthalate, allyl acrylate, triallyl theaterate, diallyl maleate, dichloroallyl maleate, diallyl itaconate, diallyl sebacate, diallyl adipate, diallyl malonate, diallyl glycolate , Triallylic aconitic acid, Triaryl acid, triallyl citrate, allyl methacrylate, diallyl fumarate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, cyclohexyl methacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, butane 1,4 diol di Ester plasticizers such as methacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, trimethylolpropane propylene oxide adduct triacrylate, dimethylaminoethyl methacrylate, 1,3-butylene glycol dimethacrylate; as other plasticizers, Low molecular weight polyethylene, low molecular weight polypropylene, low molecular weight Polystyrene, oligoester acrylate, liquid rubber, dicyclopentadiene resins, petroleum resins, polyhydroxy polyolefin, polybutene-1, microcrystalline wax, liquid polybutadiene or its modified product or hydrogenated product, liquid Thiokol, and the like.

Examples of the flame retardant include tetrabromoethane, octabromodiphenyl oxide, decabromodiphenyl oxide, hexabromocyclododecane, tribromoneopentyl alcohol, hexabromobenzene, decabromodiphenylethane, tris (tribromophenoxy) S triazine, Tris (2,3-dibromopropyl) isocyanurate, bis (tribromophenoxy) ethane, ethylenebis (tetrabromophthalimide), tetrabromobisphenol A halide, tetrabromobisphenol A carbonate oligomer, tetrabromobisphenol S, tris- ( 2,3-dibromopropyl-1-) isocyanurate, halogenated epoxy resin, antimony silico oxide, tris (chloroethyl) phosphine , Tris (dibromophenyl) phosphate, tris (tribromoneopentyl) phosphate, diethyl-N, N-bis (2-hydroxyethyl) aminomethyl phosphate, halogenated phosphate, chlorinated paraffin, chlorinated polyethylene, Chlorocyclopentadecanone, tetrabromobisphenol A, tetrabromophthalic anhydride, dibromoneopentyl alcohol, tribromophenol, pentabromobenzyl polyacrylate, chlorendic acid, dibromocresyl glycidyl ether, dibromophenyl glycidyl ether, chlorendic anhydride, tetra Halogen flame retardants such as chlorophthalic anhydride; triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate , Xylenyl diphenyl phosphate, resorcinol-bis- (diphenyl phosphate), 2-ethylhexyl diphenyl phosphate, dimethylmethyl phosphate, triallyl phosphate and the like, and its condensate, ammonium phosphate and its condensate, diethyl N, N-bis ( Phosphorus flame retardants such as 2-hydroxyethyl) aminomethylphosphonate; magnesium hydroxide, aluminum hydroxide, zinc borate, barium borate, kaolin clay, calcium carbonate, alumite, basic magnesium carbonate, calcium hydroxide, hydro Examples include inorganic flame retardants such as talcite, red phosphorus, guanidine compounds, melamine compounds, antimony trioxide, antimony pentoxide, sodium antimonate, and silicone resins.
Examples of the filler include silica, alumina, zinc oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, ferrite oxides, calcium hydroxide, aluminum hydroxide, basic magnesium carbonate, etc. Hydroxides, calcium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, dosonite, hydrotalcite and other carbonates, calcium sulfate, barium sulfate, gypsum fiber sulfates, calcium silicate, talc, clay, mica, montmorillonite , Activated clay, sepiolite, imogolite, sericite, glass fiber, glass beads, silicates, nitrides such as aluminum nitride, boron nitride, silicon nitride, carbon black, graphite, carbon fiber, carbonized balloon, charcoal powder, etc. Fillers: acrylic rubber, acrylic Nitrile / butadiene rubber, isoprene rubber, urethane rubber, liquid rubber, ethylene / propylene rubber, ethylene / propylene / diene rubber, SBR rubber, NBR rubber, chlorosulfonated polyethylene, chloroprene rubber, silicone rubber, polysulfide rubber, Examples thereof include synthetic rubbers such as butadiene rubber, butyl rubber, fluororubber, styrene / butadiene rubber, natural rubber, nylon powder, fluororesin powder, wood filler, leather powder, pulp, rubber powder, and other organic fillers.

Examples of the antioxidant include phenol-based, phosphorus-based, amine-based, sulfur-based antioxidants, weathering stabilizers, and the like.
These other components may be appropriately blended in the resin composition together with the thermoplastic resin powder and the hollow particles, or may be contained in the thermoplastic resin powder in advance.
(Combination ratio of each component of the resin composition)

The mixing ratio of the hollow particles is usually 1 to 20 parts by weight, preferably 3 to 18 parts by weight, more preferably 5 to 16 parts by weight, and further preferably 7 to 14 parts by weight with respect to 100 parts by weight of the thermoplastic resin powder. Parts, particularly preferably 9 to 12 parts by weight. When the mixing ratio of the hollow particles is less than 1 part by weight with respect to 100 parts by weight of the thermoplastic resin powder, the molded product cannot be sufficiently reduced in weight. On the other hand, when the blending ratio of the hollow particles exceeds 20 parts by weight with respect to 100 parts by weight of the thermoplastic resin powder, not only the surface properties of both the front and back surfaces of the obtained molded product are deteriorated, but also the molded product. Becomes brittle and mechanical properties deteriorate.
The mixing ratio of other components is not particularly limited, but is preferably 0.1 to 200 parts by weight, more preferably 1 to 150 parts by weight, still more preferably 3 to 100 parts by weight, and particularly preferably 5 to 50 parts by weight. Parts, most preferably 10 to 30 parts by weight. When the blending ratio of the other components is less than 0.1 parts by weight with respect to 100 parts by weight of the thermoplastic resin powder, the effect of blending the other components cannot be sufficiently obtained. On the other hand, when the blending ratio of the other components exceeds 200 parts by weight with respect to 100 parts by weight of the thermoplastic resin powder, the surface properties are deteriorated on both the front surface and the back surface, the original properties of the thermoplastic resin are lost, and molding is performed. The physical properties of the physical properties may deteriorate.

The method for producing the resin composition is not particularly limited as long as other components are appropriately mixed together with the thermoplastic resin powder and the hollow particles.
As a method for producing the resin composition, for example, there is a method (dry blend method) in which a thermoplastic resin powder and hollow particles are mixed using a gas such as air as a medium. In this method, for example, the thermoplastic resin powder and the hollow particles are mixed using a stirrer such as a tumbler mixer, a Henschel mixer, or a V-type blender.
As another method for producing the resin composition, first, in the process of preparing the thermoplastic resin powder, the hollow particles are supplied to the pulverizer together with the thermoplastic resin pellets, and the pellets are pulverized to produce the thermoplastic resin powder. At the same time, a method of dry blending with hollow particles can be exemplified. When other components are blended, they may be added simultaneously with dry blending. When the other components are liquid, they may be added by spraying.

(Molded product)
The molded product of the present invention is obtained by powder slush molding of the resin composition described above.
The true specific gravity of the molded product is not particularly limited, but is preferably 1.1 g / cc or less, more preferably 0.4 to 1.0 g / cc, still more preferably 0.5 to 0.95 g / cc, particularly Preferably it is 0.6-0.90 g / cc, Most preferably, it is 0.7-0.85 g / cc. If the true specific gravity of the molded product exceeds 1.1 g / cc, the light weight effect may not be sufficient. On the other hand, when the true specific gravity of the molded product is small, the surface properties are lowered on both the front surface and the back surface of the molded product, and the mechanical properties may be significantly lowered.

  Although there is no limitation in particular about the manufacturing method of a molded object, if powder slush molding is performed using a resin composition, there will be no limitation in particular. As a method for producing a molded product, first, as shown in FIG. 2A, the resin composition (12) is sprayed on the inner surface of a preheated mold (11), and melted and adhered to the inner surface of the mold. Let Next, as shown in (B), an amount of the resin composition necessary for molding is adhered to the inner surface of the mold by rotating the mold or the like, and an excessive amount of the resin composition is removed from the inner surface of the mold. remove. Next, the mold is heated to form a uniform film by heating the mold with hot air, infrared rays, radiant heat, or the like using a heating furnace, and the mold is formed as shown in (C). A molded product (13) is obtained by cooling and taking out from the mold. The surface of the obtained molded product may be smooth or may have an uneven pattern. In powder slush molding, a molded product having a multilayer structure can be obtained by repeating molding several times without removing the obtained molded product from the mold.

  Examples of the use of the molded product of the present invention include automotive interior skin materials such as instrument panels, glove inboxes, steering wheel covers, and airbag storage covers, chair armrests, carpets, bags, shoes, and other designs. Furniture, furniture for which cushioning properties are required, and skin materials for miscellaneous goods.

The present invention is described in detail in the following examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, “parts” means “parts by weight” and “%” means “% by weight”.
About the molding manufactured by the following example and the comparative example, the physical property was measured and evaluated in the way shown below. Examples 1 and 4 are used as reference examples.

[Measurement of specific gravity of molded product]
The specific gravity of the molded product was measured by a liquid immersion method using a precision specific gravity meter AX200 (manufactured by Shimadzu Corporation).

[Surface properties of molded products]
The surface properties of the surface (surface that was in contact with the mold; the surface of the mold) and the back surface (surface that was not in contact with the mold; back surface) of the molded product were visually evaluated according to the following evaluation criteria.
(Surface property of mold surface)
○: There is no pinhole or the like, and the design is maintained.
X: Pinholes are generated, and a decrease in designability is observed due to a wrinkle flow or the like.
(Surface property on the back)
○: There are no pinholes and the surface is smooth.
X: Pinhole is generated and not smooth.

Example 1
(Preparation of resin composition)
100 parts of polyethylene-based thermoplastic resin powder (pulverized product of PE DNDV0405R manufactured by Dow Chemical Co., average particle size 150 μm; resin 1 in Table 1), glass balloon 1 (manufactured by Sumitomo 3M, trade name Glass Bubbles, true specific gravity 0) (2 g / cc, average particle size 60 μm) was dry mixed with a Henschel mixer to prepare a resin composition.
(Powder slush molding)
100 parts of the obtained resin composition was added to a mold preheated to 200 ° C., brought into contact for 15 seconds, and then rotated left and right 5 times each. The excess resin composition that did not adhere to the mold was removed, and then the mold was heated at 270 ° C. for 30 seconds to obtain a molded product. The specific gravity of the obtained molded product was measured, and the surface property was also evaluated. The results are shown in Table 1.

[Examples 2 to 8 and Comparative Examples 1 to 4]
A resin composition was prepared in the same manner as in Example 1 except that the types of thermoplastic resin powder and hollow particles and the blending amounts thereof were changed as shown in Table 1 in Example 1, and powder slush molding was performed. To obtain a molded product. The physical properties of the obtained molded product were evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Resin 1: Polyethylene thermoplastic resin powder manufactured by Dow Chemical Company (pulverized product of PE DNDV0405R, average particle size 150 μm)
Resin 2: Polypropylene thermoplastic resin powder manufactured by Mitsui Chemicals Co., Ltd. (milled product of Miralastomer 6030N, average particle size 300 μm)
Resin 3: Urethane thermoplastic resin powder manufactured by DIC BAYER POLYMER (Pandex T1180 pulverized product, average particle size 100 μm)
Glass balloon 1: Glass balloon made by Sumitomo 3M (K20, true specific gravity 0.2 g / cc, average particle diameter 60 μm)
Glass balloon 2: Glass balloon manufactured by Sumitomo 3M (S60HS, true specific gravity 0.6 g / cc, average particle diameter 30 μm)
Microparticle-attached hollow particles 1: Matsumoto Yushi Seiyaku Co., Ltd. microparticle-attached hollow particles (Matsumoto Microsphere MFL-81GCA, true specific gravity 0.25 g / cc, average particle diameter 30 μm)
Fine particle-attached hollow particle 2: Fine particle-attached hollow particle manufactured by Matsumoto Yushi Seiyaku Co., Ltd. (Matsumoto Microsphere MFL-HD60CA, true specific gravity 0.12 g / cc, average particle diameter 60 μm)
Hollow particles 1: Hollow particles manufactured by Matsumoto Yushi Seiyaku Co., Ltd. (Matsumoto Microsphere FK-40DEH, true specific gravity 0.045 g / cc, average particle diameter 40 μm)
Hollow particles 2: Hollow particles manufactured by Matsumoto Yushi Seiyaku Co., Ltd. (Matsumoto Microsphere F-80DE, true specific gravity 0.024 g / cc, average particle diameter 60 μm)
Hollow particles 3: Hollow particles manufactured by Matsumoto Yushi Seiyaku Co., Ltd. (Matsumoto Microsphere F-80SDE, true specific gravity 0.030 g / cc, average particle diameter 30 μm)
Hollow particles 4: those obtained by foaming thermally expandable microspheres (Matsumoto Microsphere F-82D) manufactured by Matsumoto Yushi Seiyaku Co., Ltd. (true specific gravity 0.015 g / cc, average particle diameter 100 μm)

  From Table 1, in Examples 1-8, the surface property was excellent in both the surface and the back surface of the molded product obtained by powder slush molding, and a lightweight molded product could be obtained. However, in Comparative Examples 1 and 2, although a lightweight molded product was obtained, the surface properties of both the front surface and the back surface were not satisfied. In Comparative Example 1, the molded product was fragile. In Comparative Examples 3 and 4, although the surface property was satisfactory, the molded product was not lightweight.

DESCRIPTION OF SYMBOLS 1 Hollow particle 2 Outer shell part 3 Hollow part 4 Fine particle (adsorbed state)
5 Fine particles (indented and fixed state)
11 Mold 12 Resin composition 13 Molded product

Claims (5)

A resin composition used in powder slush molding,
Including hollow particles of thermoplastic resin powder and outer shell portion made of thermoplastic resin ,
The true specific gravity of the hollow particles is 0.02 to 0.30 g / cc, the average particle size is 0.8 to 60 μm,
The hollow particles are 1 to 20 parts by weight with respect to 100 parts by weight of the thermoplastic resin powder.
Resin composition. The resin composition of Claim 1 whose true specific gravity of the said hollow particle is 0.02-0.15 g / cc . The resin composition according to claim 1 or 2 , wherein fine particles adhere to the outer surface of the outer shell portion. The manufacturing method of a molded object formed by carrying out the powder slush molding of the resin composition in any one of Claims 1-3 . The method for producing a molded product according to claim 4 , wherein the true specific gravity is 1.1 g / cc or less.

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