JP5485564B2 - Method for producing aromatic polycarbonate resin composition - Google Patents

Description

The present invention relates to a method for producing a thermoplastic resin composition. Specifically, a thermoplastic resin composed of an aromatic polycarbonate resin and an aromatic polyester resin, which is suitable for injection molding, particularly gas injection injection molding, contains a rubber polymer, an organic phosphate compound, a lubricant, an inorganic filler, and the like. The present invention relates to a method for producing a thermoplastic resin composition that can be molded in a stable molding cycle and gives a molded product having sufficient practical strength and good surface appearance.

A thermoplastic resin composition comprising an aromatic polycarbonate resin and an aromatic polyester resin has excellent moldability, mechanical properties, chemical resistance, and dimensional stability, and is therefore widely used in various industrial fields. Yes. In particular, in the fields of automobile exteriors and interior parts, their excellent surface design and light weight have been evaluated and are being widely used.

In recent years, in the automotive field and the electric / electronic field, a gas injection injection molding method that gives a hollow molded product has attracted attention for the purpose of reducing the cost by reducing the weight and shortening the molding cycle and applying it to a large molded product. In the automotive field where weight reduction is particularly demanding, the interest in gas injection injection molding is particularly high.

It is well known that a thermoplastic resin composition composed of an aromatic polycarbonate resin and an aromatic polyester resin is used for a general injection molding method or a gas injection injection molding method, and various resin compositions suitable for this are proposed. (See Patent Documents 1 to 4). However, conventionally proposed resin compositions have insufficient moldability and surface design, and may have poor impact resistance. In addition, depending on the resin composition, melt plasticization is unstable, and as a result, the hollow stability may be lost or silver streaks may occur on the surface.

JP-A-5-222283 Japanese Patent Laid-Open No. 7-149948 JP 2008-231440 A Japanese Patent Laid-Open No. 2003-12912

In view of the above-mentioned problems of the prior art, the object of the present invention is excellent in mechanical strength such as tensile strength and impact strength, excellent in heat resistance, chemical resistance and paintability, and stable in the molding cycle during injection molding. It is an object of the present invention to provide a resin composition for injection molding which has excellent properties and at the same time has excellent gas injection properties.

As a result of the study, the present inventors have made an injection molding in which a thermoplastic polymer comprising an aromatic polycarbonate resin and an aromatic polyester resin contains a rubbery polymer, an organic phosphate compound, a lubricant, and, if desired, an inorganic filler. In the production of the resin composition for use, it has been found that the above-mentioned object can be achieved by first melt-kneading components other than the lubricant into pellets and attaching the lubricant thereto.

The present invention has been achieved based on this finding, and the gist thereof is from 5 to 95% by mass of the aromatic polycarbonate resin (A1) and 95 to 5% by mass (total 100% by mass) of the aromatic polyester resin (A2). 70 to 99.5 parts by mass of the thermoplastic resin (A), 30 to 0.5 parts by mass of the rubber polymer (B) (100 parts by mass in total of (A) and (B)), and (A) and (B) A mixture containing 0.02 to 1 part by mass of an organic phosphate compound (C) and 0 to 60 parts by mass of an inorganic filler (D) is melt-kneaded to form 100 pellets with respect to a total of 100 parts by mass, It is a manufacturing method of the resin composition for injection molding which mixes 100 mass parts of this pellet and 0.01-0.1 mass part of lubricant (E), and makes a lubricant adhere to a pellet, Comprising: Injection molding is gas injection molding. Yes, and the pellets and lubricants During mixing or after resides in a manufacturing method of an injection molding resin composition characterized by exposing to a temperature comprised a lubricant in a molten state. Another gist of the present invention resides in a production method for producing a hollow molded article using this resin composition by a gas injection injection molding method.

The resin composition for injection molding obtained by the production method according to the present invention is excellent in mechanical strength such as low temperature impact resistance, tensile strength, bending strength, heat resistance, chemical resistance, surface design, Excellent cycle stability and gas injection properties, giving molded products that can be used in a wide range of environments from low to high temperatures, including electrical / electronic / OA equipment parts, automotive parts, precision machine parts, medical equipment parts, miscellaneous goods, etc. Can be used in the field of Especially, it is suitable for manufacture of the exterior member for motor vehicles, making use of the outstanding low temperature impact resistance, heat resistance, chemical resistance, surface design property, and gas injection property.

The present invention will be described in detail below.
As is well known, the aromatic polycarbonate resin (A1) is produced by an interfacial polymerization method in which an aromatic dihydroxy compound is reacted with phosgene or a transesterification method in which it is reacted with a carbonic acid diester. Can also be used. In the transesterification method, the terminal OH group concentration may be adjusted by reacting the terminal blocking agent, but those subjected to this treatment can also be used.

As the raw material aromatic dihydroxy compound, 2,2-bis (4-hydroxyphenyl) propane (= bisphenol A) is mainly used, but as is well known, other aromatic dihydroxy compounds such as tetramethylbisphenol A are used. Bis (4-hydroxyphenyl) -P-diisopropylbenzene, hydroquinone, resorcinol, 4,4′-dihydroxydiphenyl, and the like can also be used. In addition, in order to impart flame retardancy to the resulting resin, a compound in which tetraalkylphosphonium sulfonate is bonded to the above aromatic dihydroxy compound, a polymer or oligomer having a siloxane structure and having a phenolic OH group at both ends are used. It can also be used together.

In the present invention, a polycarbonate resin derived from 2,2-bis (4-hydroxyphenyl) propane, which is usually easily available on the market, is used, but other polycarbonate resins such as 2,2-bis (4-hydroxy) are used. Copolymeric polycarbonate resins derived from (phenyl) propane and other aromatic dihydroxy compounds can also be used. Two or more polycarbonate resins may be used in combination.

In the present invention, as the aromatic polycarbonate resin (A1), those having a viscosity average molecular weight (Mv) of 14,000 to 30,000 are usually used. If the viscosity average molecular weight is too low, the mechanical strength of the resin composition is remarkably reduced. Conversely, if the viscosity average molecular weight is too high, the fluidity is remarkably reduced. The viscosity average molecular weight is preferably 15000 to 29000, and most preferably 16000 to 28000. The viscosity average molecular weight is calculated based on the solution viscosity measured at a temperature of 25 ° C. using methylene chloride as a solvent.

In the present invention, as the aromatic polycarbonate resin (A1), not only a virgin product but also a product regenerated from a used product, a so-called material recycled product can be used. For example, optical recording media such as optical disks, light guide plates, automobile window glass and automobile headlamp lenses, vehicle transparent members such as windshields, containers such as water bottles, spectacle lenses, soundproof walls, glass windows, and building materials such as corrugated plates It is possible to use those reproduced from the above. Moreover, what was regenerated from defective products, sprues, runners, etc. at the time of molding can also be used.

As the aromatic polyester resin (A2), a thermoplastic polyester resin obtained by subjecting an aromatic dicarboxylic acid as a main acid component to a polycondensation reaction with an alcohol mainly containing an aliphatic glycol is used. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and diphenyldicarboxylic acid. The aliphatic glycols include α, ω-alkylene glycols having 2 to 10 carbon atoms such as ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol and the like. , Neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and the like. Furthermore, bisphenol A polyoxyethylene glycol, polyoxytetramethylene glycol, and the like are also included.

As is well known, an aromatic polyester resin can be copolymerized with a hydroxycarboxylic acid such as parahydroxybenzoic acid, a carboxylic acid other than an aromatic dicarboxylic acid, or an alcohol other than an aliphatic diol. Any copolymer resin can also be used. However, such copolymerization component is preferably a small amount, and 80% by mass or more, more preferably 90% by mass or more of the aromatic polyester resin is preferably a component from aromatic dicarboxylic acid and aliphatic diol. . The aromatic dicarboxylic acid and the aliphatic diol each preferably occupy 80 mol% or more, more preferably 90 mol% or more, with one compound.

Specific examples of the polyester resin include polybutylene terephthalate, polybutylene naphthalate, polycyclohexanedimethanol terephthalate, polyethylene terephthalate, and polyethylene naphthalate. These may contain a copolymerization component. Of these, polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) are preferably used in the present invention, and it is also preferable to use both in combination. When used in combination, the ratio is preferably PET: PBT = 1: 1 to 1: 8 (mass ratio).

As the polymerization catalyst for the polyethylene terephthalate resin, germanium compounds, antimony compounds, tin compounds, titanium compounds and the like are known. In the present invention, it is preferable to use a polymer obtained by polymerizing a germanium compound as a catalyst. When using what was polymerized with another catalyst, there exists a tendency for the thermal stability and recyclability of the aromatic polycarbonate resin composition finally obtained to fall. Germanium compounds used as catalysts include germanium oxides such as germanium dioxide, germanium alkoxides such as germanium tetraethoxide, germanium tetraisopropoxide, germanium hydroxide and its alkali metal salts, germanium glycolate, germanium chloride, germanium acetate, etc. Is mentioned. These may be used alone or in combination of two or more. Among these, it is preferable to use germanium dioxide from the viewpoints of solvent resistance and thermal stability of the obtained polyethylene terephthalate resin.

It is preferable to use a germanium catalyst so that it may become 15 ppm-40 ppm as a germanium atom in the polyethylene terephthalate resin to produce | generate. If it is less than 15 ppm, the polymerization reaction proceeds slowly, and if it exceeds 40 ppm, a side reaction may occur due to the germanium compound remaining in the resin.

As the polybutylene terephthalate resin, a polymer obtained by polymerizing a titanium compound as a main catalyst and a Group 1 metal compound or Group 2 metal compound as a cocatalyst is preferably used. Examples of the titanium compound include inorganic titanium compounds such as titanium oxide and titanium tetrachloride; titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate and tetrabutyl titanate; titanium phenolates such as tetraphenyl titanate and the like. . Of these, titanium alcoholates are preferably used. Most preferred are tetraalkyl titanates, especially tetrabutyl titanate.

The titanium compound is preferably used in the resulting polybutylene terephthalate resin so as to be 20 to 50 ppm, particularly 30 to 40 ppm in terms of titanium atoms. If the amount of the titanium compound used is too large, the color tone and hydrolysis resistance of the resulting polybutylene terephthalate resin may decrease, or solution haze and foreign matter increase may occur due to deactivation of the titanium catalyst. Conversely, if the amount is too small, the polymerizability of the polybutylene terephthalate resin is lowered.

As the aromatic polyester resin (A2), one having an intrinsic viscosity of 0.4 to 2.0 measured at 30 ° C. in a mixed solvent of phenol and tetrachloroethane (mass ratio = 50/50) is usually used. If a material having an intrinsic viscosity of less than 0.4 is used, the mechanical strength of the resin composition is inferior. Conversely, if it has a viscosity exceeding 2.0, the moldability tends to decrease. The preferred intrinsic viscosity of the aromatic polyester resin is 0.6 to 1.2.

The compounding ratio of the aromatic polyester resin (A2) and the aromatic polycarbonate resin (A1) is 5 to 95% by mass of the aromatic polycarbonate resin and 95 to 5% by mass (100% by mass in total) of the aromatic polyester. When the blending amount of the aromatic polyester resin (A2) is less than 5% by mass, the chemical resistance of the resin composition is insufficient, and when it exceeds 95% by mass, the heat resistance and impact resistance may be lowered. A preferable blending ratio of the two is 51 to 90% by mass of the aromatic polycarbonate resin (A1) and 49 to 10% by mass of the aromatic polyester resin (A2), that is, a composition containing a large amount of the polycarbonate resin. Especially, aromatic polycarbonate resin 60-80 mass% and aromatic polyester resin 40-20 mass% are preferable.

As the rubber polymer (B) used in the present invention, those generally used for improving impact resistance by blending with a polyester resin or polycarbonate resin may be used. For example, so-called rubber or rubber obtained by graft polymerization of a compound that reacts with rubber is used. The glass transition temperature of the rubber polymer (B) is preferably 0 ° C. or lower, particularly preferably −20 ° C. or lower.

Specific examples of the rubber polymer (B) include, for example, polybutadiene, polyisoprene, diene copolymers (styrene / butadiene copolymer, acrylonitrile / butadiene copolymer, acrylic / butadiene rubber, etc.), ethylene and carbon. Copolymers with α-olefins of several or more (ethylene / propylene copolymers, ethylene / butene copolymers, ethylene / octene copolymers, etc.), copolymers of ethylene and unsaturated carboxylic acid esters (ethylene・ Methyl methacrylate copolymers, ethylene / butyl acrylate copolymers, etc., copolymers of ethylene and aliphatic vinyl compounds, terpolymers of ethylene, propylene and non-conjugated dienes, acrylic rubber (polybutyl acrylate, poly ( 2-ethylhexyl acrylate), butyl acrylate, 2-ethyl Sill acrylate copolymers), silicone rubber (a polyorganosiloxane rubber, a polyorganosiloxane rubber and a polyalkyl (meth) IPN type composite rubber consisting of acrylate rubber), and the like. These may be used alone or in combination of two or more. In the present specification, (meth) acrylate means acrylate and methacrylate, and (meth) acrylic acid means acrylic acid and methacrylic acid.

Another example of the rubber polymer (B) is a copolymer obtained by graft polymerization of a monomer component to the above rubber polymer. Examples of this monomer include aromatic vinyl compounds, vinyl cyanide compounds, (meth) acrylic acid ester compounds, (meth) acrylic acid compounds, and the like. In addition, epoxy group-containing (meth) acrylic acid ester compounds such as glycidyl (meth) acrylate; maleimide compounds such as maleimide, N-methylmaleimide and N-phenylmaleimide; α, β- such as maleic acid, phthalic acid and itaconic acid Examples thereof also include unsaturated carboxylic acid compounds and anhydrides thereof (for example, maleic anhydride). These monomers can be used alone or in combination of two or more.

The rubber polymer (B) is preferably of the core / shell type graft copolymer type from the viewpoint of improving the impact resistance of the resin composition. Above all, rubber selected from butadiene component-containing rubber, butyl acrylate component-containing rubber and silicone rubber is used as a core layer, and a monomer selected from acrylic acid ester, methacrylic acid ester and aromatic vinyl compound is grafted around it. A core / shell type graft copolymer comprising a shell layer formed in this manner is particularly preferred.

Examples of core / shell type graft copolymers include methyl methacrylate-butadiene-styrene polymer (MBS), methyl methacrylate-acrylonitrile-butadiene-styrene polymer (MABS), methyl methacrylate-butadiene polymer (MB), methyl Methacrylate-acrylic rubber polymer (MA), methyl methacrylate-acrylic rubber-styrene polymer (MAS), methyl methacrylate-acrylic-butadiene rubber copolymer, methyl methacrylate-acrylic-butadiene rubber-styrene copolymer, methyl methacrylate- (Acrylic / silicone IPN (interpenetrating polymer network) rubber) polymer and the like. These rubbery polymers may be used alone or in combination of two or more.

The compounding amount of the rubber polymer (B) is 70 to 99.5 parts by mass of the thermoplastic resin (A), 30 to 0.5 parts by mass of the rubber polymer, preferably 75 to 99 parts by mass of the thermoplastic resin, and rubber. 25 to 1 part by mass (total 100 parts by mass) of the conductive polymer. When the blending amount of the rubber polymer (B) is less than 0.5 parts by mass, the effect of improving the impact resistance is small, and when it exceeds 40 parts by mass, the heat resistance and rigidity may be lowered. The compounding amount of the rubber polymer (B) is most preferably 98 to 80 parts by mass of the thermoplastic resin (A) and 2 to 20 parts by mass (100 parts by mass in total) of the rubber polymer (B).

  The organic phosphate ester compound (component C) used in the present invention has a partial structure in which 1 to 3 alkoxy groups or aryloxy groups are bonded to a phosphorus atom. In addition, a substituent may further be bonded to these alkoxy groups and aryloxy groups. Preferably, an organic phosphate compound represented by any one of the following general formulas (1) to (5) is used. Two or more organic phosphate compounds may be used in combination.

In General Formula (1), R ^{1 to} R ⁴ each independently represents an alkyl group or an aryl group. M represents an alkaline earth metal or zinc.

In the general formula (2), R ⁵ represents an alkyl group or an aryl group, and M represents an alkaline earth metal or zinc.

In general formula (3), R < ⁶ > -R < ¹¹ > represents an alkyl group or an aryl group each independently. M ′ represents a metal atom that becomes a trivalent metal ion.

In general formula (4), R < ¹² > -R < ¹⁴ > represents an alkyl group or an aryl group each independently. M ′ represents a metal atom to be a trivalent metal ion, and two M ′ may be the same or different.

In the general formula (5), R ¹⁵ represents an alkyl group or an aryl group. n represents an integer of 0 to 2. When n is 0 or 1, two R ¹⁵ may be the same or different.

In general formulas (1) to (5), R ^{1 to} R ¹⁵ are usually an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms. From the viewpoints of residence heat stability, chemical resistance, and heat and humidity resistance, an alkyl group having 2 to 25 carbon atoms is preferable, and an alkyl group having 6 to 23 carbon atoms is most preferable. Examples of the alkyl group include octyl group, 2-ethylhexyl group, isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group, hexadecyl group, octadecyl group and the like. Further, M in the general formulas (1) and (2) is preferably zinc, and M ′ in the general formulas (3) and (4) is preferably aluminum.

  As the organic phosphate compound, the organic phosphate compound represented by the general formula (1) and the organic phosphorus represented by the general formula (2) from the viewpoint of further improving the thermal stability and heat and humidity resistance. It is preferable to use a mixture of acid ester compounds. Further, from the viewpoint of improving the residence heat stability, it is also preferable to use an organic phosphate compound represented by the general formula (5) in combination with these mixtures. The organophosphate esterified compound represented by the general formula (1) and the organophosphate ester compound represented by the general formula (2) are mixed at a mass ratio of 10/90 to 90/10. preferable. More preferably, it is 20 / 80-60 / 40, Especially preferably, it is 30 / 70-50 / 50.

  Specific examples of the organic phosphate compound include a bis (distearyl acid phosphate) zinc salt as the compound of the general formula (1), a monostearyl acid phosphate zinc salt as the compound of the general formula (2), and the general formula (3). The compound of the formula (4) is a tris (distearyl acid phosphate) aluminum salt, the compound of the general formula (4) is a salt of one monostearyl acid phosphate and two monostearyl acid phosphate aluminum salts, Examples of the compound 5) include monostearyl acid phosphate and distearyl acid phosphate. These may be used alone or as a mixture. Examples of commercially available products include “LBT-1830” and “LBT-1813” manufactured by Sakai Chemical Industry, “JP-518Zn” manufactured by Johoku Chemical Industry, and “Adeka Stub AX-71” manufactured by Asahi Denka Kogyo.

The organic phosphate compound is blended in an amount of 0.02 to 1 part by mass with respect to 100 parts by mass in total of the thermoplastic resin (A) and the rubber polymer (B). If the blending amount is small, the impact resistance, residence heat stability and chemical resistance of the resin composition cannot be secured sufficiently. On the other hand, when the blending amount is too large, mold contamination occurs when the resin composition is injection-molded, and the impact strength of the molded product also decreases. The compounding amount of the organic phosphate is preferably 0.05 parts by mass or more, particularly preferably 0.1 parts by mass or more with respect to a total of 100 parts by mass of (A) and (B), and the upper limit is 0.5. It is preferable that it is a mass part, especially 0.3 mass part.

As the lubricant (E), organic lubricants generally used in thermoplastic resin compositions can be used. Usually, those selected from the group consisting of fatty acids, fatty acid metal salts, fatty acid esters, so-called waxes, aliphatic hydrocarbon compounds and polysiloxane silicone oils are used.

  Examples of the fatty acid include saturated or unsaturated aliphatic monovalent to trivalent carboxylic acids. Fatty acids also include alicyclic carboxylic acids. Usually, it is preferable to use a monovalent or divalent fatty acid having 6 to 36 carbon atoms. Specific examples of fatty acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, mellicic acid, tetrariacontanoic acid, montanic acid, adipic acid, azelaic acid Etc. Of these, saturated monovalent fatty acids are preferred.

  Examples of the fatty acid constituting the fatty acid ester include the same fatty acids as described above. Examples of the alcohol include saturated or unsaturated monovalent or polyhydric alcohols. These alcohols may have a substituent such as a fluorine atom or an aryl group. Among these, a monovalent or polyvalent saturated alcohol having 30 or less carbon atoms is preferable, and an aliphatic saturated monohydric alcohol or polyhydric alcohol having 30 or less carbon atoms is more preferable. Here, aliphatic includes alicyclic compounds. Examples of preferred alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, dipentaerythritol and the like. Can be mentioned.

  Specific examples of fatty acid esters include beeswax (mixture based on myricyl palmitate), stearyl stearate, behenyl behenate, stearyl behenate, glycerin monopalmitate, glycerin monostearate, glycerin distearate, Examples thereof include glycerin tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, pentaerythritol tetrastearate and the like. Examples of fatty acid metal salts include salts of the above fatty acids with alkaline earth metals, zinc, lead, tin and the like.

As the aliphatic hydrocarbon, those having a number average molecular weight of 200 to 15000 are usually used, and liquid paraffin, paraffin wax, micro wax, polyethylene wax, Fischer-Tropsch wax, α-olefin oligomer having 3 to 12 carbon atoms, and the like are used. Can be mentioned. Here, as the aliphatic hydrocarbon, alicyclic hydrocarbon is also included. Moreover, these hydrocarbon compounds may be partially oxidized. Among these, paraffin wax, polyethylene wax, or a partial oxide of polyethylene wax is preferable, and paraffin wax and polyethylene wax are more preferable. The number average molecular weight is preferably 200 to 5,000. These aliphatic hydrocarbons may be a single substance, or may be a mixture of various constituent components and molecular weights, as long as the main component is within the above range.

  Examples of the polysiloxane silicone oil include dimethyl silicone oil, phenylmethyl silicone oil, diphenyl silicone oil, and fluorinated alkyl silicone. Two or more of these may be used in combination.

  The lubricant is blended in an amount of 0.01 to 0.5 parts by mass with respect to 100 parts by mass in total of the thermoplastic resin (A) and the rubber polymer (B). When the content of the lubricant is less than 0.01 parts by mass, the measurement stability and the release property may not be sufficient. Preferably, 0.02 parts by mass or more of the lubricant is blended. On the other hand, when the blending amount exceeds 0.5 parts by mass, there are problems such as slipping on the screw and poor biting property or mold contamination when producing a molded product by injection molding. From these points, the blending amount of the lubricant is preferably 0.2 parts by mass or less, particularly preferably 0.1 parts by mass or less.

In the present invention, the lubricant is not melt-kneaded together with the thermoplastic resin (A) or the like, but first contains the thermoplastic resin (A), the rubbery polymer (B), the organic phosphate compound (C) and optionally. The inorganic filler (D) to be melted is mixed to produce pellets, and the pellets and lubricant are mixed to adhere the lubricant to the surface of the pellets. Thereby, static electricity on the surface of the pellet is reduced, and the pellets can be prevented from aggregating. As a result, at the time of injection molding, pellets are smoothly supplied to the plasticizing zone of the molding machine, and sticking of the pellets to the screw surface can be prevented, so that the measurement stability is improved.

The lubricant is preferably attached so that the static electricity on the surface of the pellet is -0.5 kv or more, particularly -0.3 kv or more. Static electricity can be adjusted by the amount of lubricant and the state of adhesion. In order to bring static electricity to a desired value with a small amount of lubricant, it is considered that the lubricant is preferably attached to the surface of the pellet in the form of a film. In order to make it adhere in a film form, the pellets may be mixed with the pellets at a temperature equal to or higher than the temperature at which the lubricant melts or in the molten state. As another method, after mixing the lubricant in powder form, there is a method in which the pellets to which the lubricant has adhered are exposed to a temperature higher than the temperature at which the lubricant melts. For these reasons, it is preferable that the temperature at which the lubricant becomes a molten state (melting point or dropping point) is 160 ° C. or lower.

  The thermoplastic resin composition of the present invention preferably contains an inorganic filler (D) for the purpose of improving strength and rigidity. The shape of the inorganic filler is arbitrary such as a needle shape, a plate shape, a granular shape or an amorphous shape. Specific examples of inorganic fillers include glass fillers such as glass fibers (chopped strands), short glass fibers (milled fibers), glass flakes, and glass beads; carbon fillers such as carbon fibers, carbon short fibers, carbon nanotubes, and graphite. ; Whisker such as potassium titanate and aluminum borate; Silicate compounds such as talc, mica, wollastonite, kaolinite, zonotolite, sepiolite, attabargite, montmorillonite, bentonite, smectite; silica, alumina, calcium carbonate, etc. . Among these, talc, mica, wollastonite, and kaolinite are preferable for the purpose of obtaining good surface design. Two or more of these may be used in combination.

  Content of an inorganic filler is 0-60 mass parts with respect to a total of 100 mass parts of a thermoplastic resin (A) and a rubber-like polymer (B). In order to express the effect of the inorganic filler, at least 1 part by mass should be contained. When the content of the inorganic filler is less than 1 part by mass, the reinforcing effect may not be sufficient. Moreover, when it exceeds 60 mass parts, an external appearance and impact resistance may be inferior, and fluidity | liquidity may not be enough. The content of the inorganic filler is preferably 3 to 50 parts by mass, particularly preferably 5 to 30 parts by mass.

From the viewpoint of thermal stability when the inorganic filler is contained in the resin composition, a granular material having an average particle diameter of 0.01 to 100 μm granulated with a binder is preferable. The average particle diameter is more preferably 0.05 to 50 μm, and further preferably 0.1 to 25 μm. If the average particle size is too small, the reinforcing effect tends to be insufficient. Conversely, if the average particle size is too large, the product appearance tends to be adversely affected, and the impact resistance may be insufficient. The most preferable average particle diameter of the inorganic filler is 0.2 to 15 μm, particularly 0.3 to 10 μm. Note the average particle size of the inorganic filler in the present invention refers to a D ₅₀ measured by a liquid phase precipitation method using X-ray transmission. As an apparatus capable of performing such measurement, a Sedigraph particle size analyzer (“Model 5100” manufactured by Micromeritics Instruments) can be mentioned.

Silica compounds such as wollastonite, talc, mica, zonotolite, sepiolite, attabargite, kaolinite; composites such as potassium titanate, titanium oxide, alumina oxide, zinc oxide Oxides; carbonate compounds such as calcium carbonate; sulfate compounds such as barium sulfate and calcium sulfate; carbon-based fillers such as graphite and carbon black; silica; glass-based fillers such as glass flakes and glass beads; aluminum borate and the like These may be used alone or in combination of two or more.

  Among these, from the viewpoint of the balance of rigidity, fluidity, impact resistance, and product appearance, those in which silicate compounds such as wollastonite, talc, mica, zonotlite, sepiolite, attabalgite, kaolinite are granulated are preferable, It is particularly preferable to use granular talc.

Talc is a hydrous magnesium silicate having a layered structure, the chemical formula is represented by _{4SiO 2 · 3MgO · H 2 O} , the normal SiO ₂ 58 to 66 wt%, the MgO 28 to 35 wt%, of _{H 2} O About 5% by mass is contained. As other minor components, Fe ₂ O ₃ is 0.03 to 1.2% by mass, Al ₂ O ₃ is 0.05 to 1.5% by mass, CaO is 0.05 to 1.2% by mass, and K ₂ O is 0.2 wt% or less, Na ₂ O are contained below 0.2 wt%, a specific gravity of about 2.7.

  The average particle diameter of the raw material for granular talc is preferably 0.1 to 10 μm, more preferably 0.3 to 8 μm, and particularly preferably 0.7 to 5 μm. When the average particle size is 0.1 μm or more, the thermal stability of the resin composition tends to be further improved, and when the average particle size is less than 10 μm, the appearance and rigidity of the molded product of the resin composition are further improved. Tend to.

  Moreover, it is preferable that the granular talc is surface-treated in order to improve the affinity with the thermoplastic resin (A). Specific examples of the surface treatment agent include alcohols such as trimethylolethane, trimethylolpropane, and pentaerythritol, alkanolamines such as triethylamine, organosilicone compounds such as organopolysiloxane, higher fatty acids such as stearic acid, Fatty acid metal salts such as calcium stearate and magnesium stearate, polyethylene wax, hydrocarbon lubricants such as liquid paraffin, basic amino acids such as lysine and arginine, polyglycerin and their derivatives, silane coupling agents, titanate couplings And at least one selected from coupling agents such as an agent and an aluminum-based coupling agent.

  The bulk density of the granular talc is 0.4 to 1.5 g / ml, more preferably 0.5 to 1.3 g / ml, and particularly preferably 0.6 to 1.1 g / ml. When the bulk density is 0.4 g / ml or more, the thermal stability and impact resistance of the resin composition tend to be further improved. On the other hand, when the bulk density is less than 1.5 g / ml, the resin composition There is a tendency that the appearance and impact resistance of the molded product are further improved.

Here, the bulk density is a value obtained by the following method.
(1) Place the granular talc on a sieve with an aperture of 1.4 mm, and pass through the sieve while sweeping lightly with a brush.
(2) The granular talc passed through the sieve is put into a receiver attached to the bulk density measuring device specified in JIS K5101 until it reaches a heap.
(3) Scrap off the granular talc that is piled up from the inlet of the receiver with a spatula, measure the weight of the granular talc in the receiver, and calculate the bulk density using the following equation.
Bulk density (g / ml) = weight of granular talc in the receiver (g) / capacity of receiver (ml)

  As the granular talc, in general, a resin composition having a mesh ratio of 55% by mass or more is used because the thermal stability of the resin composition tends to be further improved. It is preferable to use a sieve having a ratio of 60% by mass or more, more preferably 70% by mass or more. Most preferably, the sieve is 90% by mass or more.

Here, the particle size of the granular talc is a value determined by the following method in accordance with JIS Z8801.
(1) Place the granular talc on a sieve having an opening of 2 mm, and pass the sieve while sweeping lightly with a brush.
(2) Put the granular talc passed through a sieve into a 200 ml beaker, and use a sample reducer (for example, sample reducer “13056 6” manufactured by Yoshida Seisakusho (groove width 6 mm)) to about 30 ml. Reduce until
(3) The above-mentioned granular talc is sieved using a sieve having an opening of 500 μm, the weight not passing through the 500 μm sieve is obtained, and the ratio from the total amount is obtained. In addition, sieving is performed for 10 minutes at a vibration frequency of 120 times / second using a vibration sieve (for example, “Electromagnetic Vibrating Sieve M-100 Model” manufactured by Tsutsui Chemical Co., Ltd.).

The binder used when producing granular talc is highly granulated with raw material talc, is colorless or white, is an inert and stable substance, and has the physical properties of a molded product produced from a resin composition. Any material that does not decrease can be used, and examples thereof include clay minerals such as bentonite that exhibit high caking properties under wet conditions, colloidal silica, gypsum, water-soluble polymers, waxes, higher fatty acids, and resin powders. Of these, clay minerals and water-soluble polymers are preferable, and water-soluble polymers are more preferable from the viewpoint of thermal stability, impact resistance, and rigidity of the resin composition.

Examples of the water-soluble polymer include polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, sodium polyacrylate, sodium alginate, agar, and polysaccharides (celluloses such as methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropulosecellulose, sodium carboxymethylcellulose) Derivatives and starch), proteins (gelatin, glue, etc.) and the like.
Among these, polysaccharides and proteins having high caking properties and high adsorptivity with talc are more preferable, among which sodium carboxymethylcellulose (hereinafter sometimes abbreviated as “CMC”) and gelatin are more preferable. CMC is particularly preferable.

  CMC is, for example, natural pulp made into alkali cellulose with sodium hydroxide and etherified with monochloroacetic acid. Production methods include a solvent method and an aqueous medium method. The properties of CMC vary depending on the degree of polymerization and the degree of etherification in units of anhydrous glycol. The preferred CMC used in the present invention is an average polymerization degree of 100 to 500, an etherification degree of 0.5 to 1.7, and a 1% aqueous solution viscosity (25 ° C., type B) from the viewpoint of solubility in water and aqueous solution viscosity. Viscometer) is in the range of 10 to 500 mPa · sec, and those outside these ranges may cause problems in terms of granulation.

  The binder content in the granular talc is preferably 0.01 to 5% by mass, more preferably 0.05 to 3.5% by mass, and particularly preferably 0.1 to 2% in 100% by mass of the granular talc. % By mass. When the binder content is 0.01% by mass or more, the granular talc is difficult to collapse during handling, and when the binder content is less than 5% by mass, the granular talc is disintegrated and dispersed in the resin composition. Tends to be more favorable, and the appearance and impact resistance of the molded product of the resin composition tend to be further improved.

In the production of granular talc, the kneadability between talc and binder is increased, plasticity is imparted to the kneaded product at the time of granule production, facilitating the production, reducing the wear of the granulator, and the granular product It is preferable to add a wetting agent in order to adjust the hardness. Usually, a lubricant is added to talc and a binder, and if necessary, a dispersant and other additives are added to obtain a mixture while stirring with a mixer such as a Henschel mixer or a super mixer.
This mixture is kneaded with a single-screw or twin-screw extruder, etc., extruded into strands, cut and granulated, and dried using a fluid dryer or band heater to produce granular talc. To do.

  The shape of the granular talc is not particularly limited, such as a rod shape, a columnar shape, a needle shape, a spherical shape, a granular shape, a flake shape, and an indeterminate shape, and various shapes can be produced depending on molding conditions and sizing conditions. For example, when producing rod-shaped or cylindrical particles, the shaft diameter can be appropriately set by changing the size of the screen opening of the screen-type extruder, and after shaping, the particles can be sized and cut to the desired shaft length. it can. If it is in the range of said bulk density and a particle size, there will be no restriction | limiting in particular also in the magnitude | size.

  Examples of the lubricant include water and organic solvents, but water is preferable from the viewpoint of cost and workability, and alcohols may be mixed with water. It is possible to dissolve or suspend the binder in water, which is a wetting agent. Additives required for granules, such as dispersants, surfactants, and various synthetic resin additives The uniformity can be further improved by dissolving or suspending the dye or pigment. Further, when water is used as the lubricant, it is preferable to dry the moisture contained using a fluid dryer or the like so that the moisture content is 1% or less, and more preferably 0.3% or less. 80-150 degreeC is suitable for drying temperature, Preferably it is 80-110 degreeC.

In the present invention, when the dispersant is contained in the granular talc in an amount of 0.05 to 2.0% by mass, preferably 0.1 to 0.5% by mass, the granular talc is disintegrated in the resin composition molded product. In some cases, dispersibility is improved. Dispersants used may be generally known, for example, alcohols, alkanolamines, organic silicone compounds, higher fatty acids, fatty acid metal salts, hydrocarbon lubricants, basic amino acids, polyglycerols and their derivatives as described above. Can be mentioned.
Furthermore, the granular talc may contain various additives in addition to the dispersant, as long as the characteristics of the present invention are not impaired. Such additives include various antioxidants such as hindered phenols, various heat stabilizers such as phosphites, various ultraviolet absorbers such as benzotriazoles, benzophenones, and triazines, silicones, and metal salts. Various flame retardants such as olefins, various release agents such as olefin waxes and fatty acid esters, antibacterial and antifungal agents such as phenols, anionic, cationic and nonionic antistatic agents, colorants, talc Other fillers, light stabilizers, plasticizers, foaming agents, anti-dripping agents, and the like. Further, the organophosphate compound (C) can be contained in granular talc and contained in the resin composition. In addition, these various additives include, in addition to the granular talc, a thermoplastic polymer (A), a rubber polymer (B), an organic phosphate compound (C), an inorganic filler (D), and the like. You may mix | blend independently, when melt-kneading and manufacturing a pellet.

    Since the resin composition of the present invention has excellent impact resistance, chemical resistance, high cycle performance, dimensional stability, and fluidity, interior parts such as vehicles and aircraft, exterior parts, electric / electronic / Suitable for a wide range of applications such as OA equipment parts, mobile phones, machine parts, building materials, recreational goods and miscellaneous goods.

  Specifically, for example, there are outer handles, door mirror sticks, fenders, garnishes, bumpers, roof rails, wiper arms, etc. as automotive exterior parts, and inner handles, center console, instrument panel, assist grip, seats as automotive interior parts. Examples include belt stoppers.

  Rail vehicle parts include table arms, suspension hands, and assist grips. Electric parts include shaver frames, dryers, refrigerator handles and pullers, microwave oven doors, portable MD system handles, and headphone arms. And a housing for an electric screwdriver. Examples of building material parts include door handles, crescents, and French droppings.

The resin substrate of the present invention is preferably used particularly for vehicle / aircraft outer or inner handle applications because of its excellent appearance and productivity.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. The raw materials used in Examples and Comparative Examples are as follows.

Polycarbonate resin Aromatic polycarbonate resin (1): Bisphenol A type aromatic polycarbonate produced by an interfacial polymerization method. Iupilon E-2000, viscosity average molecular weight 28000 manufactured by Mitsubishi Engineering Plastics.

Polyester resin Polybutylene terephthalate resin (1): NOVADURAN 5020 manufactured by Mitsubishi Engineering Plastics Co., Ltd., intrinsic viscosity 1.20 dl / g.
Polybutylene terephthalate resin (2): NOVADURAN 5008 manufactured by Mitsubishi Engineering Plastics Co., Ltd., intrinsic viscosity 0.85 dl / g.
Polyethylene terephthalate resin (1): Novapex GG500 (germanium atom content 28 ppm, intrinsic viscosity 0.76 dl / g) manufactured by Mitsubishi Chemical Corporation.
In addition, the intrinsic viscosity of each polyester resin described above is a value measured at 30 ° C. in a 1: 1 (weight ratio) mixed solution of phenol and tetrachloroethane.

  Rubber polymer: Core / shell type graft copolymer comprising polybutadiene (core) / alkyl acrylate / alkyl methacrylate copolymer (shell) EXL2603 manufactured by Rohm and Haas Japan.

Organophosphate compound (1): Chemical formula O = P (OH) _n (OC ₁₈ H ₃₇ ) _3-n (mixture of n = 1 and 2) ADK STAB AX-71 manufactured by Asahi Denka Kogyo Co., Ltd.
Organophosphate compound (2): Mixture of zinc salt of distearyl acid phosphate and zinc salt of monostearyl acid phosphate (weight ratio 33/67). JP-518Zn made by Johoku Chemical Industry.

Thermal stabilizer: Tris (2,4-di-tert-butylphenyl) phosphite Adeka Stub AS2112 manufactured by Asahi Denka Kogyo Co., Ltd.
Granular talc: “MTB-12” manufactured by Matsumura Sangyo Co., Ltd., talc average particle size of 1.8 μm, bulk density of 0.74 g / ml, particle size / aperture of 500 μm, 98% by weight, particle shape / columnar shape, Average shaft diameter 1.2mm, average shaft length 1.5mm, binder type / CMC

Lubricant (1): Pentaerythritol tetrastearate Cognis Oleochemicals Japan Roxyol VPG861 Melting point 64 ° C
Lubricant (2): Pentaerythritol distearate Unistar H-476DP, melting point 53 ° C., manufactured by Nippon Oil & Fats Co., Ltd.
Lubricant (3): Polyethylene wax Clariant Japan Co., Ltd. Lycowax PE-520 Drop point 117-122 ° C
Lubricant (4): Calcium stearate, Nippon Oil & Fats Co., mp 145-160 ° C

Reference Examples 1-6 and Examples 1-3
<Preparation of resin composition>
After uniformly mixing components other than the lubricant shown in Table 1 and Table 3 with a tumbler-mixer in the ratio shown in the table, a twin screw extruder (“TEX30XCT” manufactured by Nippon Steel Works, L / D = 42, Using a barrel number 12), pellets of the resin composition were prepared by supplying the mixture from the barrel 1 to the extruder at a cylinder temperature of 280 ° C. and a screw rotation speed of 250 rpm, followed by melt kneading. The obtained pellets and lubricant were put into a tumbler and stirred for about 20 minutes to obtain a resin composition in which the lubricant adhered to the surface of the pellets.

<Measurement of pellet static electricity>
The pellets having the lubricant adhered thereon were dried at 120 ° C. for 5 hours or more and then put into a molding machine hopper, and the static electricity of the pellets was measured using KDS-0102 manufactured by Kasuga Electric Co., Ltd. The measurement was performed at a distance of 10 cm from the pellet. The results are shown in Tables 1 and 3.

<Preparation of test piece by injection molding ( Reference Examples 1 to 6 )>
After drying the resin composition pellets obtained above at 120 ° C. for 5 hours or longer, the AZ-7000 type injection molding machine manufactured by Nissei Plastic Industry has a handshake part at the center and parts attached to the vehicle body at both ends. A mold for molding an outer handle for automobiles (2 pieces) was attached, and 20 shots were continuously molded under the conditions of a cylinder temperature of 280 ° C., a mold temperature of 80 ° C., and a molding cycle of 60 seconds.

<Production of test pieces by gas injection injection molding (Examples 1 to 3 )>
After the pellets of the resin composition obtained above are dried at 120 ° C. for 5 hours or longer, a handshake part is provided in the center part of the AZ-7000 type injection molding machine manufactured by Nissei Plastic Industry, and attachment parts to the vehicle body are provided at both ends. Attach outer car molds for automobiles (two take, have gas injection nozzles at both ends), cylinder temperature 280 ° C, mold temperature 60 ° C, filling time 7 seconds, gas injection delay 8 seconds, gas pressure 30 shots were continuously molded under the conditions of 10 MPa, gas holding time of 35 seconds, and molding cycle of 83 seconds.

<Appearance inspection of handle (visual)>
The appearance of the automobile outer handle obtained above was evaluated in the following four stages. The results are shown in Tables 1 and 3.
0: No silver 1: Low (Silver is recognized in either one of the vehicle mounting parts 2: Medium (Silver is recognized in both of the vehicle mounting parts)
3: Large (approved for the entire handle)

<Screw noise>
Screw squeal at the time of molding the outer handle for automobiles was evaluated according to the following four levels. The results are shown in Tables 1 and 3.
0: None 1: Small 2: Medium 3: Large

<Dispersion of measurement average time and measurement time>
The measurement average time and the measurement time variation (maximum measurement time-minimum measurement time) during molding of the outer handle for automobiles were evaluated. The results are shown in Tables 1 and 3.

<Measurement of impact resistance (Charpy impact strength with notch)>
The resin composition obtained above was dried at 120 ° C. for 5 hours or more, and then using a FANUC “α100iA type” injection molding machine, the cylinder temperature was 280 ° C., the mold temperature was 80 ° C., and the molding cycle was 40 seconds. Then, an ISO tensile test piece (thickness: 4.0 mm) was injection molded. In accordance with ISO 179, a notched test piece having a thickness of 4.0 mm is produced from this test piece, and the notched Charpy impact strength (unit: KJ / m ² ) is measured at 23 ° C. and −30 ° C. did. The results are shown in Table 1.

<Coating test>
A urethane resin paint (manufactured by Kansai Paint Co., Ltd., Retan PG80 White) was applied to the test piece obtained above with a coating film thickness of 50 μm, followed by curing at 80 ° C. for 30 minutes. Next, 11 cuts each having a width of 1 mm were placed with a cutter knife, making 100 squares each having a size of 2 mm × 2 mm, and a cellophane adhesive tape (manufactured by Nichiban Co., Ltd., Celote Tape (registered trademark) CT). -18) was stretched over the squares and then pulled apart, and the completely remaining squares (residual squares) were measured (goblin eye test). The results are shown in Table 1.

Comparative Examples 1-10
<Preparation of resin composition>
After the components shown in Table 2 and Table 3 were uniformly mixed with a tumbler-mixer at the ratio shown in the table, a twin-screw extruder (“TEX30XCT” manufactured by Nippon Steel Works, L / D = 42, barrel number 12) Was used, and was supplied to the extruder from the barrel 1 at a cylinder temperature of 280 ° C. and a screw rotation speed of 250 rpm, and melt kneaded to prepare pellets of the resin composition.

<Molding>
Using this pellet, the outer molding was performed by the same injection molding method as in Reference Examples 1 to 6 (Comparative Examples 1 to 8), or by the same gas injection injection molding method as in Examples 1 to 3 (Comparative Examples 9 to 10). A handle and an ISO tensile test piece were prepared and evaluated. The results are shown in Table 2 and Table 3.

Claims (13)

70-99.5 parts by mass of a thermoplastic resin (A) composed of 5-95% by mass of an aromatic polycarbonate resin (A1) and 95-5% by mass (total of 100% by mass) of an aromatic polyester resin (A2), rubbery 30 to 0.5 parts by mass of the polymer (B) (100 parts by mass in total of (A) and (B)), and 100 parts by mass of (A) and (B) in the organophosphate compound ( C) A mixture containing 0.02 to 1 part by mass and inorganic filler (D) 0 to 60 parts by mass was melt-kneaded into pellets, and 100 parts by mass of the pellets and lubricant (E) 0.01 to 0.5 It is a method for producing a resin composition for injection molding, in which a mass part is mixed and a lubricant is adhered to pellets,
A method for producing a resin composition for injection molding, wherein the injection molding is gas injection molding and the lubricant is exposed to a temperature at which it is in a molten state during or after mixing the pellet and the lubricant.   The thermoplastic resin (A) is composed of 51 to 95% by mass of an aromatic polycarbonate resin (A1) and 49 to 5% by mass (total 100% by mass) of an aromatic polyester resin (A2). The manufacturing method of the resin composition for injection molding of Claim 1. 80 to 98 parts by mass of a thermoplastic resin (A) composed of 60 to 80% by mass of an aromatic polycarbonate resin (A1) and 40 to 20% by mass (total of 100% by mass) of an aromatic polyester resin (A2), a rubber polymer (B) 20 to 2 parts by mass (100 parts by mass in total of (A) and (B)), and 100 parts by mass of (A) and (B) in the organic phosphate ester compound (C) 0. A mixture containing 05 to 0.3 parts by mass and an inorganic filler (D) 0 to 60 parts by mass is melt-kneaded to form pellets, and 100 parts by mass of the pellets and lubricant (E) 0.01 to 0.1 parts by mass. A method for producing a resin composition for injection molding, wherein the lubricant is adhered to the pellets by mixing the
A method for producing a resin composition for injection molding, wherein the injection molding is gas injection molding and the lubricant is exposed to a temperature at which it is in a molten state during or after mixing the pellet and the lubricant. The resin composition for injection molding according to any one of claims 1 to 3 , wherein the aromatic polyester resin (A2) is selected from the group consisting of a polyethylene terephthalate resin and a polybutylene terephthalate resin. Production method. Aromatic polyester resin (A2) is a polyethylene terephthalate resin and polybutylene terephthalate resin 1: 1 to 1: 8 claims 1, characterized in that is a mixture (mass ratio) to one of the 3 The manufacturing method of the resin composition for injection molding of description. The method for producing a resin composition for injection molding according to any one of claims 1 to 5 , wherein the rubber polymer (B) is a core / shell type graft polymer. The organic phosphate compound (C) is selected from the group consisting of a phosphate ester having a partial structure in which an alkoxy group or an aryloxy group is bonded to a phosphorus atom, and a metal salt thereof. The manufacturing method of the resin composition for injection molding in any one of 1 thru | or 6 . The method for producing a resin composition for injection molding according to any one of claims 1 to 6 , wherein the organic phosphate compound is represented by the following general formula (1) or (2).

(Wherein R ¹ to R ⁴ each independently represents an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms. M is selected from the group consisting of alkaline earth metals and zinc). Represents a divalent metal.)

(In the formula, R ⁵ represents an alkyl group or an aryl group, and M represents an alkaline earth metal or zinc.) The inorganic filler (D) is granular talc obtained by granulating talc having an average particle size of 0.1 to 10 µm so that a bulk density is 0.4 to 1.5 g / ml. The manufacturing method of the resin composition for injection molding in any one of 1 thru | or 8 . The method for producing a resin composition for injection molding according to any one of claims 1 to 9 , wherein the lubricant (E) is melted at 160 ° C to be in a fluid state. Lubricant (E) is selected from the group consisting of polyethylene waxes, fatty acids, of the injection molding resin composition according to any one of 10 claims 1, characterized in that a member selected from the group consisting of fatty acid metal salts and fatty acid esters Production method. The method for producing a resin composition for injection molding according to any one of claims 1 to 11 , wherein the lubricant is adhered to the pellet so that the surface static electricity of the pellet is -0.5 kv or more. A molded article having a hollow portion produced by a gas injection injection molding method using the resin composition for injection molding obtained by the production method according to any one of claims 1 to 12. Manufacturing method.