JP2015151461A - Method for manufacturing micro-foam molded article, and micro-foam molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a lightweight micro-foam molded article having uniform micro-foam cells and high impact strength, and to provide a micro-foam molded article.SOLUTION: The method for manufacturing a micro-foam molded article includes the steps of: (1) kneading a resin (A) that forms a sea phase containing polycarbonate and a resin (B) that forms an island phase containing at least one selected from polyester, polyolefin, and polyamide, to prepare a resin composition having a sea-island structure; (2) melt-kneading the resin composition in an injection molding machine to disperse the resin (B) that forms the island phase, as particles having a number average particle diameter of 10 μm or less, into the resin (A) that forms the sea phase; (3) injecting a supercritical gas into the resin composition in a melt state; and (4) injection molding the resin composition with the supercritical gas injected thereto to form micro-foam cells in the island phase in the molded article.

Description

  The present invention relates to a method for producing a fine foam molded article and a fine foam molded article, and more specifically, a method for producing a fine foam molded article having fine and uniform foam cells, and a fine foam molded article produced by the production method. About.

  As a material for automobiles and OA equipment, a molded body using polycarbonate, which is generally excellent in strength, is frequently used. For the purpose of reducing the cost by reducing the weight of the molded body and reducing the amount of material used, a technique for producing a molded body having foam cells inside the molded body by injection molding is known. However, if the polycarbonate single resin is foamed, coarse foam cells are formed inside the molded body. When a coarse foam cell is formed, when the molded body receives an impact, the coarse foam cell is the starting point and the molded body is damaged, and sufficient strength cannot be obtained.

  For this reason, it is required to disperse the foamed cells present in the molded body finely and uniformly, and as a means for this, a method of adding an inorganic filler which is the starting point of the foamed cells to the resin is generally known. However, when the inorganic filler is added, the mass of the molded body becomes heavy, and the effect of reducing the weight, which is the original purpose, is diminished.

  A method has been proposed in which polycarbonate and polylactic acid are mixed and a supercritical gas is combined to achieve both strength and light weight (for example, see Patent Document 1). However, this method is aimed at improving the strength of polylactic acid by alloying with polycarbonate, but a significant reduction in strength due to weight reduction by forming foam cells in the alloy material is inevitable.

  In addition, a method of obtaining a foam by dispersing another thermoplastic resin impregnated with a supercritical gas in a thermoplastic resin has been proposed (for example, see Patent Document 2). However, in this method, molding is performed at a temperature equal to or lower than the melting temperature of the thermoplastic resin impregnated with the supercritical gas. Therefore, with the kneading ability of a normal injection molding machine, the thermoplastic resin impregnated with the supercritical gas is the other. Difficult to uniformly disperse in thermoplastic resin. Therefore, the inside of the molded body has a structure in which foamed cells are gathered locally, resulting in a decrease in strength. In addition, there is a problem that the variation in physical properties for each molding shot becomes large.

JP 2007-161853 A JP 2010-254930 A

  The present invention has been made in view of the above-described problems and circumstances, and a solution to the problem is a method for producing a fine foam molded article having fine and uniform foam cells, light weight and high impact strength, and a fine foam molded article. Is to provide.

  In order to solve the above problems, the present inventor has a sea-island structure composed of a continuous phase that forms a sea phase and an independent phase that forms an island phase in the process of examining the cause of the above-described problem, and the like. A fine foam molded article having fine foam cells formed in a molten resin composition in which a resin that forms an island phase is dispersed in advance as fine particulate matter in a resin that forms a sea phase.・ By injecting the supercritical gas into the resin composition while kneading and then making it by injection molding, a fine foam molded body with fine and uniform foam cells, light weight and high impact strength can be obtained. The present invention has been found.

  That is, the said subject which concerns on this invention is solved by the following means.

1. A method for producing a microfoamed molded article having a sea-island structure comprising a continuous phase forming a sea phase and an independent phase forming an island phase, and having micro-foamed cells formed inside the island phase, the sea phase When the resin (A) that forms the resin contains polycarbonate and the content of the polycarbonate is 100 parts by mass, the resin (B) that forms the island phase is at least one selected from polyester, polyolefin, and polyamide. The manufacturing method of the fine foaming molding characterized by containing in the range of 10-60 mass parts, and forming through at least following process (1)-(4).
(1) Step of preparing a resin composition having a sea-island structure by kneading the resin (A) forming the sea phase and the resin (B) forming the island phase (2) Injection molding the resin composition Step of melting and kneading in a machine to disperse the resin (B) forming the island phase in the resin (A) forming the sea phase as a particulate matter having a number average particle size of 10 μm or less (3) Molten state A step of injecting a supercritical gas into the resin composition (4) a step of forming a fine foam cell inside the island phase in the molded body by injection molding the resin composition into which the supercritical gas has been injected. 2. 2. The method for producing a finely foamed molded article according to item 1, wherein the resin (B) forming the island phase contains polyester.

  3. 3. The method for producing a fine foam molded article according to item 1 or 2, wherein the supercritical gas is nitrogen gas.

4). A micro-foamed molded article having a sea-island structure composed of a continuous phase forming a sea phase and an independent phase forming an island phase, and having micro-foamed cells formed inside the island phase, and forming the sea phase When the resin (A) contains a polycarbonate and the content of the polycarbonate is 100 parts by mass, the resin (B) forming the island phase is 10 to 60 at least one selected from polyester, polyolefin and polyamide. A fine foam molded article, which is contained within the range of part by mass and formed through at least the following steps (1) to (4).
(1) Step of preparing a resin composition having a sea-island structure by kneading the resin (A) forming the sea phase and the resin (B) forming the island phase (2) Injection molding the resin composition Step of melting and kneading in a machine to disperse the resin (B) forming the island phase in the resin (A) forming the sea phase as a particulate matter having a number average particle size of 10 μm or less (3) Molten state A step of injecting a supercritical gas into the resin composition (4) a step of forming a fine foam cell inside the island phase in the molded body by injection molding the resin composition into which the supercritical gas has been injected. 5. The fine foam molded article according to item 4, wherein the resin (B) forming the island phase contains polyester.

  6). 6. The microfoamed molded article according to item 4 or 5, wherein the supercritical gas is nitrogen gas.

  By the above-mentioned means of the present invention, it is possible to provide a method for producing a fine foam molded article having fine and uniform foam cells, light weight and high impact strength, and a fine foam molded article.

  The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

  The present invention relates to a resin composition having a sea-island structure in which a crystalline resin selected from polyester, polyolefin, and polyamide forms an island phase in a polycarbonate that forms a sea phase. It is the manufacturing method of the fine foaming molding manufactured by shaping | molding. Here, the resin (B) that forms the island phase becomes the starting point of foaming, so that fine foam cells can be formed inside the island phase. That is, in the injection molding machine, the resin (B) that forms the island phase is dispersed as particulate matter in the resin (A) that forms the sea phase. The critical gas is dissolved. The resin (B) that forms this island phase is a crystalline resin and is dispersed in a molten state, but is crystallized in the process of being cooled in the mold and simultaneously decompressed in the mold. This crystal is considered to be the starting point of foaming, and the supercritical gas dissolved in the resin that forms the island phase foams as a gas, thereby forming fine foam cells inside the island phase. .

  That is, the supercritical gas is dissolved in both the sea phase and the island phase resin, but in the state immediately after being injected into the mold, the crystalline resin that forms the island phase melts and becomes more soluble than the sea phase. Is in a low viscosity state. Therefore, it is considered that the island phase is easier to foam than the sea phase. In the process of cooling the resin composition in the mold, crystallization of the resin in the island phase begins, and since this crystal nucleus serves as the starting point of foaming, more fine foam cells are formed in the island phase. It is thought that.

  Therefore, it is considered that the cell diameter of the foamed cells formed inside the island phase can be controlled small by dispersing the resin (B) forming the island phase as a particulate matter having a number average of 10 μm or less.

  The phrase “foamed cells are formed inside the island phase” means that the foamed cells are formed as bubbles in the resin that forms the island phase.

Schematic diagram of a cross section of a resin composition having a sea-island structure Schematic diagram of the cross-section of a fine foam molded article with fine foam cells formed

The method for producing a micro-foamed molded article of the present invention has a sea-island structure composed of a continuous phase that forms a sea phase and an independent phase that forms an island phase, and a micro-foam having a micro-foam cell formed inside the island phase. In the method for producing a molded body, when the resin (A) forming the sea phase contains polycarbonate and the content of the polycarbonate is 100 parts by mass, the resin (B) forming the island phase is: It contains at least one selected from polyester, polyolefin and polyamide in the range of 10 to 60 parts by mass, and is formed through at least the following steps (1) to (4).
(1) Step of preparing a resin composition having a sea-island structure by kneading the resin (A) forming the sea phase and the resin (B) forming the island phase (2) Injection molding the resin composition Step of melting and kneading in a machine to disperse the resin (B) forming the island phase in the resin (A) forming the sea phase as a particulate matter having a number average particle size of 10 μm or less (3) Molten state A step of injecting a supercritical gas into the resin composition (4) a step of forming a fine foam cell inside the island phase in the molded body by injection molding the resin composition into which the supercritical gas has been injected. This feature is a technical feature common to the inventions according to claims 1 to 6.

  As an embodiment of the present invention, it is preferable that the resin (B) forming the island phase is a production method containing polyester from the viewpoint of manifesting the effects of the present invention. When the resin (B) forming the island phase is a resin containing polyester, the polyester is easily dispersed in the form of fine particles in the polycarbonate, and fine foam cells can be formed during injection molding.

  Moreover, it is preferable that the supercritical gas is a production method in which nitrogen gas is used. When the supercritical gas is nitrogen gas, fine foam cells can be formed.

The fine foam molded article of the present invention is a fine foam molded article having a sea island structure composed of a continuous phase forming a sea phase and an independent phase forming an island phase, and having fine foam cells formed inside the island phase. When the resin (A) forming the sea phase contains polycarbonate and the content of the polycarbonate is 100 parts by mass, the resin (B) forming the island phase is made of polyester, polyolefin and polyamide. It contains at least one selected within a range of 10 to 60 parts by mass, and is formed through at least the following steps (1) to (4).
(1) Step of preparing a resin composition having a sea-island structure by kneading the resin (A) forming the sea phase and the resin (B) forming the island phase (2) Injection molding the resin composition Step of melting and kneading in a machine to disperse the resin (B) forming the island phase in the resin (A) forming the sea phase as a particulate matter having a number average particle size of 10 μm or less (3) Molten state A step of injecting a supercritical gas into the resin composition (4) a step of forming a fine foam cell inside the island phase in the molded body by injection molding the resin composition into which the supercritical gas has been injected. Moreover, it is preferable that the resin (B) which forms the said island phase contains polyester from a viewpoint of the effect expression of this invention. When the resin (B) forming the island phase is a resin containing polyester, the polyester is easily dispersed in the form of fine particles in the polycarbonate, and fine foam cells can be formed during injection molding.

  The supercritical gas is preferably nitrogen gas. When the supercritical gas is nitrogen gas, fine foam cells can be formed.

  Hereinafter, the constituent elements of the present invention, and modes and modes for carrying out the present invention will be described in detail. In the present application, “to” is used in the sense of including the numerical values described before and after the lower limit value and the upper limit value.

≪Fine foam molding≫
The fine foam molded article of the present invention is a fine foam molded article having a sea island structure composed of a continuous phase forming a sea phase and an independent phase forming an island phase, and having fine foam cells formed inside the island phase. When the resin (A) forming the sea phase contains polycarbonate and the content of the polycarbonate is 100 parts by mass, the resin (B) forming the island phase is made of polyester, polyolefin and polyamide. It contains at least one selected within a range of 10 to 60 parts by mass, and is formed through at least the following steps (1) to (4).
(1) Step of preparing a resin composition having a sea-island structure by kneading the resin (A) forming the sea phase and the resin (B) forming the island phase (2) Injection molding the resin composition Step of melting and kneading in a machine to disperse the resin (B) forming the island phase in the resin (A) forming the sea phase as a particulate matter having a number average particle size of 10 μm or less (3) Molten state A step of injecting a supercritical gas into the resin composition (4) a step of forming a fine foam cell inside the island phase in the molded body by injection molding the resin composition into which the supercritical gas has been injected. FIG. 1 is a schematic view of a cross section of a resin composition having a sea-island structure according to the present invention. Here, A represents the resin (A) constituting the sea phase, B represents the resin (B) constituting the island phase, and these have a sea-island structure. FIG. 2 is a schematic diagram of a cross-section of a fine foam molded article in which fine foam cells are formed, and shows that the fine foam cells C are formed in the resin (B) forming the B island phase. .

<Resin composition>
In the resin composition according to the present invention, the resin (A) that forms the sea phase contains polycarbonate, and when the content of the polycarbonate is 100 parts by mass, the resin (B) that forms the island phase is polyester. , Containing at least one selected from polyolefin and polyamide within a range of 10 to 60 parts by mass, and in the resin (A) forming the sea phase, the resin (B) forming the island phase, It is a resin composition having a sea-island structure dispersed as particulate matter. By performing injection molding using this resin composition, a fine foam molded article having fine foam cells formed inside the island phase can be produced.

  In the present invention, the sea-island structure means an island-like phase (resin (B that forms an island phase) having a closed interface (boundary between phases) in a continuous phase of the resin (A) that forms the sea phase. )). That is, the sea-island structure means that when a plurality of (for example, two) resin components that are incompatible with each other are mixed, the higher order structure of the mixture is already in the phase (sea) in which one of the resin components is continuous. A structure in which one resin is scattered in the form of islands or particles. That is, it means a structure formed by one resin being a continuous phase (sea) and the other being an island-like independent phase (dispersed phase).

<Resin forming the sea phase (A)>
The resin (A) forming the sea phase according to the present invention contains polycarbonate.

(Polycarbonate)
The polycarbonate used in the present invention is an aliphatic or aromatic polycarbonate, and the aromatic polycarbonate is an aromatic homo- or co-polymer obtained by reacting an aromatic dihydric phenol compound with phosgene or carbonic acid diester. Examples thereof include aromatic polycarbonates such as polycarbonates, and those having a glass transition temperature measured by a differential calorimeter in the range of 100 to 155 ° C are preferably used.

  Examples of the aromatic dihydric phenol compound include 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, and bis (4- Hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxy-3,5-diphenyl) butane, 2 , 2-bis (4-hydroxy-3,5-diethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-diethylphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane and 1-phenyl-1,1-bis (4-hydroxyphenyl) ethane or the like can be used, and these can be used alone or as a mixture. Moreover, you may contain one or more compounds, such as a hindered phenol type, sulfur type, and phosphorus antioxidant.

<Resin forming the island phase (B)>
In the present invention, the resin (B) forming the island phase contains at least one resin selected from polyester, polyolefin and polyamide. These resins are preferably crystalline resins, which can be present as fine crystal nuclei in the polycarbonate, and these fine crystal nuclei become the starting point of foaming during injection molding. Thus, a fine and uniform foam cell can be formed.

(polyester)
The polyester used in the present invention is a high molecular weight thermoplastic resin having an ester bond in the main chain, and is preferably a crystalline polyester. Specifically, a polycondensate of an acid component having a carboxylic acid or an ester derivative thereof as a main component and a diol component, a polycondensate of a hydroxycarboxylic acid or an ester derivative thereof, an acid component having a carboxylic acid or an ester derivative thereof as a main component And a polycondensate obtained from a cyclic ether compound or a ring-opening polymer of a cyclic ester compound.

  As carboxylic acid components, terephthalic acid, isophthalic acid, orthophthalic acid, chlorophthalic acid, nitrophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,5-naphthalene Dicarboxylic acid, methyl terephthalic acid, 4,4'-biphenyldicarboxylic acid, 2,2'-biphenyldicarboxylic acid, 4,4'-diphenylether dicarboxylic acid, 4,4'-diphenylmethanecarboxylic acid, 4,4'-diphenylsulfone Aromatic dicarboxylic acids such as dicarboxylic acid, 4,4′-diphenylisopropylidenedicarboxylic acid, 1,2-bis (4-carboxyphenoxy) -ethane, 5-sodium sulfoisophthalic acid, oxalic acid, succinic acid, adipic acid, Suberic acid, azelaic acid, sebacic acid, Decanedione acid, octadecane dicarboxylic acid, dimer acid, and alicyclic dicarboxylic acids such as aliphatic dicarboxylic acids and 1,4-cyclohexane dicarboxylic acid such as maleic acid and fumaric acid.

  Examples of the hydroxycarboxylic acid component include p-hydroxybenzoic acid, p- (hydroxyethoxybenzoic acid, 6-hydroxy-2-naphthoic acid, 4′-hydroxy-biphenyl-4-carboxylic acid and the like, and lactic acid. And aliphatic hydroxycarboxylic acids such as glycolic acid.

  Examples of the diol component include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,2-dimethylpropanediol, neopentyl glycol, 1,5-pentanediol, and 1,6-hexanediol. 1,8-octanediol, 1,10-decanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol , Octamethylene glycol, diethylene glycol, dipropylene glycol, hydroquinone, resorcinol, bisphenol A and 2,2-bis (2'-hydroxyethoxyphenyl) propane.

  Examples of the cyclic ether compound include ethylene oxide and propylene oxide. Examples of the cyclic ester compound include δ-valerolactone, β-propyllactone, γ-butyrolactone, and ε-caprolactone.

  Specific preferred thermoplastic polyesters include polyethylene terephthalate, polybutylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polyethylene terephthalate, polybutylene isophthalate, polybutylene terephthalate, Examples include polycyclohexylene dimethylene isophthalate, polycyclohexylene dimethylene terephthalate, p-hydroxybenzoic acid polyethylene terephthalate, and polylactic acid resin.

(Polyolefin)
The polyolefin used in the present invention is a homopolymer of an α-olefin such as ethylene, propylene, butene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, heptene-1 and octene-1. , Random or block-like inter-copolymers, and random, block or graft copolymers of these α-olefins with other unsaturated monomers, where other unsaturated Examples of monomers include acrylic acid, methacrylic acid, maleic acid, itaconic acid, methyl acrylate, ethyl acrylate, methyl methacrylate, maleic anhydride, glycidyl methacrylic acid, arylmaleimide, and alkylmaleimide. Saturated organic acids and their derivatives, or vinyl esters such as vinyl acetate and vinyl butyrate, Alternatively, aromatic vinyl compounds such as styrene and methylstyrene, vinylsilanes such as vinyltrimethylmethoxysilane and methacryloyloxypropyltrimethoxysilane, or non-conjugated dienes such as dicyclopentadiene and 4-ethylidene-2-norbornene are used. In the case of copolymerization, the α-olefin and other monomers are not limited to two types, and may be composed of a plurality of types. In the present invention, the polyolefin is preferably a crystalline polyolefin.

(polyamide)
The polyamide used in the present invention is a thermoplastic resin having an amide bond starting from an amino acid, lactam or diamine and a dicarboxylic acid. Examples of amino acids include 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and paraaminomethylbenzoic acid, and examples of lactam include ε-caprolactam and ω-laurolactam. In the present invention, the polyamide is preferably a crystalline polyamide.

  Examples of the diamine include tetramethylene diamine, hexamethylene diamine, undecamethylene diamine, dodecamethylene diamine, 2,2,4-trimethylhexamethylene diamine, 2,4,4-trimethylhexamethylene diamine, 5-methylnonamethylene diamine, 2,4-dimethyloctamethylenediamine, metaxylylenediamine, paraxylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 3, 8-bis (aminomethyl) tricyclodecane, bis (4-aminocyclohexyl) methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminopropyl) ) Piperazine and a Such as Bruno ethyl piperazine, and the like.

  Examples of dicarboxylic acids include adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5 -Sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid and diglycolic acid.

  In the resin composition according to the present invention, when the resin (A) constituting the sea phase contains polycarbonate and the content of the polycarbonate is 100 parts by mass, the resin (B) constituting the island phase is 10-60. It is contained within the range of part by mass. Preferably, it exists in the range of 10-40 mass parts. If the amount of the resin (B) forming the island phase is less than 10 parts by mass, the distance between the island phase and the island phase becomes wide, and the foamed cell becomes enormous when foaming. If the amount of the resin (B) forming the island phase is more than 60 parts by mass, the resin that becomes the island phase is unevenly distributed, and the foamed cells grow in the unevenly distributed large island phase, and a uniform foamed cell cannot be obtained. Moreover, in this invention, you may contain thermoplastic resins other than a polycarbonate as resin (A) which comprises a sea phase.

  In the resin composition, the resin (B) forming the island phase dispersed in the resin (A) forming the sea phase is preferably dispersed as a particulate matter having a number average particle size of 10 μm or less. In the resin composition, if the number average particle diameter of the resin (B) forming the island phase is 10 μm or less, the resin (B) forming the island phase when melted and kneaded in the injection molding machine is ensured. Therefore, the foamed cells can be made finer and uniform when formed into a molded body. Further, the resin (B) forming the island phase is more preferably dispersed with a particle diameter of a number average particle diameter of 5 μm or less.

(Compatibilizer)
In the present invention, a compatibilizer (C) may be further added. The compatibilizing agent (C) in the present invention promotes compatibilization with a resin (A) that forms a sea phase mainly composed of polycarbonate, a resin (B) that forms an island phase, and other thermoplastic resins. It has an action of finely dispersing the component (A) and the component (B). In addition, by compatibilizing the interface between the sea phase and the island phase, it has the effect of increasing impact strength when formed into a molded body.

  Examples of such a compatibilizer (C) include an inorganic filler, a polymer compound grafted or copolymerized with a glycidyl compound or an acid anhydride, a polymer compound containing an acrylic resin or a styrene resin unit by grafting, and an organometallic compound. And may be used alone or in combination of two or more.

  Moreover, the compounding amount of the compatibilizer is preferably 1 to 50 parts by mass, more preferably 3 with respect to 100 parts by mass of the total amount of the resin (A) forming the sea phase and the resin (B) forming the island phase. It is -40 mass parts, Most preferably, it is 4-30 mass parts, and the effect as a compatibilizing agent can be exhibited as it is in this range.

(Flame retardants)
In the present invention, a flame retardant (D) may be further added. The flame retardant to be used (D) is not particularly limited as long as it is a substance added for the purpose of imparting flame retardancy to the resin. Specifically, brominated flame retardants, phosphorus flame retardants, Nitrogen compound-based flame retardants, silicone-based flame retardants, and other inorganic flame retardants can be used, and at least one of these can be selected and used.

  Specific examples of the brominated flame retardant used in the present invention include decabromodiphenyl oxide, octabromodiphenyl oxide, tetrabromodiphenyl oxide, tetrabromophthalic anhydride, hexabromocyclododecane, bis (2,4,6-tribromo). Phenoxy) ethane, ethylenebistetrabromophthalimide, hexabromobenzene, 1,1-sulfonyl [3,5-dibromo-4- (2,3-dibromopropoxy)] benzene, polydibromophenylene oxide, tetrabromobisphenol-S, Tris (2,3-dibromopropyl-1) isocyanurate, tribromophenol, tribromophenyl allyl ether, tribromoneopentyl alcohol, brominated polystyrene, brominated polyethylene, tetrabromobis Enol-A, tetrabromobisphenol-A derivative, tetrabromobisphenol-A-epoxy oligomer or polymer, tetrabromobisphenol-A-carbonate oligomer or polymer, brominated epoxy resin such as brominated phenol novolac epoxy, tetrabromobisphenol-A -Bis (2-hydroxydiethyl ether), tetrabromobisphenol-A-bis (2,3-dibromopropyl ether), tetrabromobisphenol-A-bis (allyl ether), tetrabromocyclooctane, ethylenebispentabromodiphenyl, Tris (tribromoneopentyl) phosphate, poly (pentabromobenzylpolyacrylate), octabromotrimethylphenylindane, dibromoneopenti Glycol, pentabromobenzyl polyacrylate, dibromo cresyl glycidyl ether, and N, N'ethylene - bis - such as tetrabromo phthalic imide. Of these, tetrabromobisphenol-A-epoxy oligomer, tetrabromobisphenol-A-carbonate oligomer and brominated epoxy resin are preferred.

  The phosphorus-based flame retardant used in the present invention is not particularly limited, and a generally used phosphorus-based flame retardant can be used. Typically, an organic phosphorus compound such as a phosphate ester or a polyphosphate, Red phosphorus is mentioned.

  Specific examples of the phosphoric acid ester in the above organic phosphorus compounds include trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri (2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl. Phosphate, tris (isopropylphenyl) phosphate, tris (phenylphenyl) phosphate, trinaphthyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, diphenyl (2-ethylhexyl) phosphate, di (isopropylphenyl) phenyl phosphate, monoisodecyl Phosphate, 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acetate Phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, melamine phosphate, dimelamine phosphate, melamine pyrophosphate, triphenylphosphine oxide, tricresylphosphine oxide, diphenyl methanephosphonate, phenylphosphonic acid Examples include condensed phosphate esters such as diethyl, resorcinol polyphenyl phosphate, resorcinol poly (di-2,6-xylyl) phosphate, bisphenol A polycresyl phosphate, hydroquinone poly (2,6-xylyl) phosphate and condensates thereof. be able to. Examples of commercially available condensed phosphate esters include PX-200, PX-201, PX-202, CR-733S, CR-741, and CR747 manufactured by Daihachi Chemical Co., Ltd.

  Moreover, the phosphate and polyphosphate which consist of a salt with phosphoric acid, polyphosphoric acid, a periodic table group IA-IVB group metal, ammonia, an aliphatic amine, and an aromatic amine can also be mentioned. As typical salts of polyphosphates, lithium salts, sodium salts, calcium salts, barium salts, iron (II) salts, iron (III) salts, aluminum salts, etc. as metal salts, methylamine salts as aliphatic amine salts, Examples include ethylamine salts, diethylamine salts, triethylamine salts, ethylenediamine salts, piperazine salts, and examples of aromatic amine salts include pyridine salts, triazine salts, melamine salts, and ammonium salts.

  In addition to the above, halogen-containing phosphate esters such as trischloroethyl phosphate, trisdichloropropyl phosphate and tris (β-chloropropyl) phosphate), and a structure in which a phosphorus atom and a nitrogen atom are connected by a double bond. Examples thereof include phosphazene compounds and phosphoric ester amides.

  The red phosphorus is preferably not only untreated red phosphorus but also red phosphorus treated with one or more compound films selected from the group consisting of thermosetting resin films, metal hydroxide films, and metal plating films. Can be used. The thermosetting resin of the thermosetting resin film is not particularly limited as long as it is a resin capable of coating red phosphorus. For example, phenol-formalin resin, urea-formalin resin, melamine-formalin resin, alkyd resin Etc. The metal hydroxide coating is not particularly limited as long as it can coat red phosphorus, and examples thereof include aluminum hydroxide, magnesium hydroxide, zinc hydroxide, and titanium hydroxide. . The metal of the metal plating film is not particularly limited as long as it can coat red phosphorus, and examples thereof include Fe, Ni, Co, Cu, Zn, Mn, Ti, Zr, Al, and alloys thereof. Further, these coatings may be used in combination of two or more, or may be laminated in two or more.

  Examples of the nitrogen compound-based flame retardant used in the present invention include aliphatic amine compounds, aromatic amine compounds, nitrogen-containing heterocyclic compounds, cyanide compounds, aliphatic amides, aromatic amides, urea and thiourea. . In addition, nitrogen-containing phosphorus flame retardants such as ammonium polyphosphate as exemplified in the above phosphorus flame retardant are not included in the nitrogen compound flame retardant referred to herein. Examples of the aliphatic amine include ethylamine, butylamine, diethylamine, ethylenediamine, butylenediamine, triethylenetetramine, 1,2-diaminocyclohexane and 1,2-diaminocyclooctane. Examples of the aromatic amine include aniline and phenylenediamine. Examples of the nitrogen-containing heterocyclic compound include uric acid, adenine, guanine, 2,6-diaminopurine, 2,4,6-triaminopyridine, and a triazine compound. Examples of the cyan compound include dicyandiamide. Examples of the aliphatic amide include N, N-dimethylacetamide. Examples of aromatic amides include N, N-diphenylacetamide.

  The triazine compounds exemplified above are nitrogen-containing heterocyclic compounds having a triazine skeleton, and are triazine, melamine, benzoguanamine, methylguanamine, cyanuric acid, melamine cyanurate, melamine isocyanurate, trimethyltriazine, triphenyltriazine, amelin, and amelide. And thiocyanuric acid, diaminomercaptotriazine, diaminomethyltriazine, diaminophenyltriazine and diaminoisopropoxytriazine.

  As melamine cyanurate or melamine isocyanurate, an adduct of cyanuric acid or isocyanuric acid and a triazine compound is preferable, usually an addition having a composition of 1 to 1 (molar ratio), optionally 1 to 2 (molar ratio). You can list things. Although it is produced by a known method, for example, a mixture of melamine and cyanuric acid or isocyanuric acid is made into a water slurry and mixed well to form both salts into fine particles, and then the slurry is filtered and dried. Later it is generally obtained in powder form. The salt does not need to be completely pure, and some unreacted melamine, cyanuric acid or isocyanuric acid may remain. Moreover, the average particle diameter before blending with the resin is preferably 0.01 to 100 μm, more preferably 1 to 80 μm from the viewpoint of flame retardancy, mechanical strength, and surface property of the molded body.

  Of the nitrogen compound-based flame retardants, nitrogen-containing heterocyclic compounds are preferable, among which triazine compounds are preferable, and melamine cyanurate is more preferable.

  When the dispersibility of the nitrogen compound flame retardant is poor, a dispersant such as tris (β-hydroxyethyl) isocyanurate or a known surface treatment agent such as polyvinyl alcohol or metal oxide may be used in combination. Good.

Examples of the silicone flame retardant used in the present invention include silicone resins and silicone oils. Examples of the silicone resin include a resin having a three-dimensional network structure formed by combining structural units of SiO ₂ , RSiO _3/2 , R ₂ SiO, and R ₃ SiO _1/2 . Here, R represents an alkyl group such as a methyl group, an ethyl group or a propyl group, an aromatic group such as a phenyl group or a benzyl group, or a substituent containing a vinyl group in the above substituent. In the silicone oil, polydimethylsiloxane, and at least one methyl group in the side chain or terminal of polydimethylsiloxane is a hydrogen element, an alkyl group, a cyclohexyl group, a phenyl group, a benzyl group, an amino group, an epoxy group, or a polyether group. A modified polysiloxane modified with at least one group selected from carboxy group, mercapto group, chloroalkyl group, alkyl higher alcohol ester group, alcohol group, aralkyl group, vinyl group, or trifluoromethyl group, or a mixture thereof. Can be mentioned.

  Other inorganic flame retardants used in the present invention include magnesium hydroxide, aluminum hydroxide, antimony trioxide, antimony pentoxide, sodium antimonate, zinc hydroxystannate, zinc stannate, metastannic acid, tin oxide, oxidation Metal of tin salt, zinc sulfate, zinc oxide, ferrous oxide, ferric oxide, stannous oxide, stannic oxide, zinc borate, calcium borate, ammonium borate, ammonium octamolybdate, tungstic acid Examples thereof include salts, complex oxide acids of tungsten and metalloid, ammonium sulfamate, graphite, and swellable graphite. Of these, aluminum hydroxide, zinc borate and swellable graphite are preferred.

  The flame retardant (D) may be used alone or in combination of two or more. In addition, when using aluminum hydroxide, it is preferable to melt-mix and use it at the kneading | mixing temperature of 210 degrees C or less.

  Among the flame retardants (D), at least one selected from a phosphorus-based flame retardant containing no halogen, a nitrogen compound-based flame retardant, a silicone-based flame retardant, and other inorganic flame retardants, or a combination of two or more. It is preferable to use it. In the above, when two or more flame retardants are used in combination, it is preferable to use a phosphorus-based flame retardant together with another flame retardant. The nitrogen compound-based flame retardant used in combination with the phosphorus-based flame retardant is preferably a nitrogen-containing heterocyclic compound, more preferably a triazine compound, and further preferably melamine cyanurate. Moreover, as a silicone type flame retardant used together with a phosphorus type flame retardant, a silicone resin is preferable. Moreover, as other inorganic flame retardants used in combination with phosphorus flame retardants, aluminum hydroxide, zinc borate and swellable graphite are preferable. The blending ratio with the phosphorus-based flame retardant can be combined with any amount, and the amount of the phosphorus-based flame retardant in 100% by mass of the flame retardant is particularly preferably 5% by mass or more, and 5 to 95% by mass. It is more preferable that

  The blending amount of the flame retardant (D) is 1 to 50 parts by mass with respect to 100 parts by mass of the total amount of the resin (A) forming the sea phase and the resin (B) forming the island phase, and further 2 -45 mass parts is preferable, Especially preferably, it is 3-40 mass parts, and sufficient flame-retarding effect is acquired as it is in this range.

(Plasticizer)
In the present invention, a plasticizer (E) can be further blended. As the plasticizer, known ones generally used as resin plasticizers can be used without particular limitation. For example, polyester plasticizer, glycerin And plasticizers, polycarboxylic acid ester plasticizers, polyalkylene glycol plasticizers, and epoxy plasticizers.

  Specific examples of the polyester plasticizer include acid components such as adipic acid, sebacic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, rosin, propylene glycol, 1,3-butanediol, 1,4 Examples thereof include polyesters composed of diol components such as butanediol, 1,6-hexanediol, ethylene glycol and diethylene glycol, and polyesters composed of hydroxycarboxylic acids such as polycaprolactone. These polyesters may be end-capped with a monofunctional carboxylic acid or monofunctional alcohol, or may be end-capped with an epoxy compound or the like.

  Specific examples of the glycerin plasticizer include glycerin monoacetomonolaurate, glycerin diacetomonolaurate, glycerin monoacetomonostearate, glycerin diacetomonooleate, and glycerin monoacetomonomontanate.

  Specific examples of polycarboxylic acid plasticizers include phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, diheptyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, and trimellitic acid. Trimellitic acid esters such as tributyl, trioctyl trimellitic acid, trihexyl trimellitic acid, diisodecyl adipate, n-octyl-n-decyl adipate, methyl diglycol butyl diglycol adipate, benzyl methyl diglycol adipate, adipic acid Adipic acid esters such as benzylbutyl diglycol, citrate esters such as triethyl acetylcitrate and tributyl acetylcitrate, azelaic acid esters such as di-2-ethylhexyl azelate, sebacin Dibutyl, and sebacic acid esters such as di-2-ethylhexyl sebacate and the like.

  Specific examples of the polyalkylene glycol plasticizer include polyethylene glycol, polypropylene glycol, poly (ethylene oxide / propylene oxide) block and random copolymer, polytetramethylene glycol, ethylene oxide addition polymer of bisphenols, and propylene of bisphenols. Examples thereof include polyalkylene glycols such as oxide addition polymers and tetrahydrofuran addition polymers of bisphenols and end-capped compounds such as terminal epoxy-modified compounds, terminal ester-modified compounds, and terminal ether-modified compounds.

  The epoxy plasticizer generally refers to an epoxy triglyceride composed of an alkyl epoxy stearate and soybean oil, but there are also so-called epoxy resins mainly made of bisphenol A and epichlorohydrin. Can be used.

  Specific examples of other plasticizers include benzoic acid esters of aliphatic polyols such as neopentyl glycol dibenzoate, diethylene glycol dibenzoate and triethylene glycol di-2-ethylbutyrate, fatty acid amides such as stearamide, oleic acid Aliphatic carboxylic acid esters such as butyl, methyl acetylricinoleate, and oxyacid esters such as butyl acetylricinoleate, pentaerythritol, polyacrylic acid esters, paraffins, orthoterphenyl, methoterterphenyl and paraorthoterphenyl And aromatic compounds.

(Crystal nucleating agent)
In the present invention, a crystal nucleating agent can be further blended. Examples of the crystal nucleating agent include known inorganic nucleating agents such as nitrides, organic nucleating agents such as organic carboxylic acid metal salts, sorbitols, and high nucleating agents. Examples thereof include molecular nucleating agents, and only one kind may be used or two or more kinds may be used in combination. In the present invention, the plasticizer and the crystal nucleating agent may each be used alone, but it is preferable from the viewpoint of moldability to use both in combination.

(Coloring agent)
In the present invention, carbon black, titanium oxide, bengara, ultramarine blue, calcined yellow, and further toning a resin to various colors by blending one or more pigments and dyes of various colors, weather resistance (light), It is also possible to improve the electrical conductivity, and the blending amount of the pigment or dye is 0. 0 parts by mass with respect to 100 parts by mass of the total amount of the resin (A) forming the sea phase and the resin (B) forming the island phase. It is 01-10 mass parts, Preferably it is 0.02-9 mass parts, More preferably, it is 0.03-8 mass parts.

Examples of the carbon black include, but are not limited to, channel black, furnace black, acetylene black, anthracene black, oil smoke, pine smoke, and graphite, and an average particle diameter of 500 nm or less, dibutyl phthalate oil absorption the amount 50~400cm 3 ^/ 100g carbon black is preferably used, aluminum oxide treatment agent, silicon oxide, zinc oxide, zirconium oxide, polyol, or may be treated with a silane coupling agent.

  Further, as the titanium oxide, titanium oxide having a crystal form such as a rutile form or anatase form and having an average particle size of 5 μm or less is preferably used, and aluminum oxide, silicon oxide, zinc oxide, zirconium oxide, It may be treated with a polyol or a silane coupling agent. In addition, the above-described carbon black, titanium oxide, and various color pigments and dyes may be blended with various thermoplastic resins or melt-blended in order to improve dispersibility with the resin composition of the present invention and to improve handling during production. It may be used as a blended mixed material.

(Stabilizer)
For the resin composition of the present invention, a stabilizer (hindered phenol-based antioxidant, phosphorus-based antioxidant, amine-based antioxidant, sulfur-based antioxidant, as long as the object of the present invention is not impaired. Light-resisting agent, UV absorber, copper damage inhibitor, etc.), mold release agent (fatty acid, fatty acid metal salt, oxy fatty acid, fatty acid ester, aliphatic partially saponified ester, paraffin, low molecular weight polyolefin, fatty acid amide, alkylene bis fatty acid Amide, aliphatic ketone, fatty acid lower alcohol ester, fatty acid polyhydric alcohol ester, fatty acid polyglycol ester, and modified silicone), or hydrolysis inhibitor (epoxy compound, carbodiimide compound, oxazoline compound, and isocinurate compound) as necessary Can be added.

(Inorganic filler)
Other fillers, other types of polymers, and the like can be added to the resin composition according to the present invention as long as the effects of the present invention are not impaired. These may be added at any time. As the filler, known materials generally used as fillers for resins are used, and the strength, rigidity, heat resistance, dimensional stability and the like of the polyester resin composition of the present invention can be improved. For example, glass fiber, carbon fiber, potassium titanate whisker, zinc oxide whisker, aluminum borate whisker, aramid fiber, alumina fiber, silicon carbide fiber, ceramic fiber, asbestos fiber, gypsum fiber, metal fiber, wollastonite, zeolite, Sericite, kaolin, mica, talc, clay, pyrophyllite, asbestos, aluminosilicate, alumina, silicon oxide, magnesium oxide, zirconium oxide, titanium oxide, iron oxide, calcium carbonate, magnesium carbonate, dolomite, calcium sulfate, barium sulfate , Magnesium hydroxide, calcium hydroxide, aluminum hydroxide, glass beads, ceramic beads, boron nitride, silicon carbide, and silica. These may be hollow, and two or more of these fillers may be used. Further, these fillers may be used after being treated with a coupling agent such as an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound, or an epoxy compound. In order to effectively reinforce the polyester resin composition of the present invention, glass fibers and carbon fibers can be added among the fillers.

≪Method for producing fine foam molded article≫
The method for producing a micro-foamed molded article of the present invention has a sea-island structure composed of a continuous phase that forms a sea phase and an independent phase that forms an island phase, and a micro-foam having a micro-foam cell formed inside the island phase. In the method for producing a molded body, when the resin (A) forming the sea phase contains polycarbonate and the content of the polycarbonate is 100 parts by mass, the resin (B) forming the island phase is: It contains at least one selected from polyester, polyolefin and polyamide in the range of 10 to 60 parts by mass, and is formed through at least the following steps (1) to (4).
(1) Step of preparing a resin composition having a sea-island structure by kneading the resin (A) forming the sea phase and the resin (B) forming the island phase (2) Injection molding the resin composition Step of melting and kneading in a machine to disperse the resin (B) forming the island phase in the resin (A) forming the sea phase as a particulate matter having a number average particle size of 10 μm or less (3) Molten state A step of injecting a supercritical gas into the resin composition (4) a step of forming a fine foam cell inside the island phase in the molded body by injection molding the resin composition into which the supercritical gas has been injected. Next, the manufacturing method and injection molding method of the resin composition will be described.

<Method for producing resin composition>
(Kneading method)
The resin composition having a sea-island structure according to the present invention includes a resin (A) that forms a sea phase, a resin (B) that forms an island phase, and, if necessary, a compatibilizer (C) and a flame retardant (D). In addition, each component of the plasticizer (E) can be obtained by kneading with a melt kneader such as a twin screw extruder excellent in kneadability.

  As the kneader, a general uniaxial or biaxial kneader can be used. Among these, a twin-screw extrusion kneader is preferable, and as such a kneader, twin-screw extrusion kneaders “KTX-30” and “KTX-46” manufactured by Kobe Steel, Ltd., manufactured by Toshiba Machine Co., Ltd. Twin screw extrusion kneaders “TEM-26SS” and “TEM-48SS” and “PCM-30” and “PCM-115” manufactured by Ikegai Co., Ltd. can be used.

  As kneading conditions, the cylinder (barrel) temperature and screw rotation speed of the kneader are appropriately adjusted according to the thermal characteristics such as the softening point of the resin (A) forming the sea phase and the resin (B) forming the island phase. By doing so, a desired dispersed resin composition can be obtained.

  In the present invention, the number average particle diameter of the resin (B) forming the island phase dispersed as particulates in the resin (A) that forms the sea phase when melted and kneaded in an injection molding machine is 10 μm or less. In order to do so, it is preferable to make the particulate material 10 μm or less at the stage of producing the resin composition. The number average particle diameter of the resin (B) that forms the island phase dispersed as particulates in the resin (A) that forms the sea phase when melted and kneaded in the injection molding machine is the supercritical gas It can be substituted by measuring the number average particle diameter of the island phase of the unfoamed molded article by injection molding without using.

≪Injection molding≫
The fine foam molded article of the present invention can be produced by injection molding, and more specifically, can be produced by fine injection foam molding (MuCell).

<Fine injection foam molding>
Micro-injection foaming is a process that involves dissolving a large amount of supercritical gas such as nitrogen or carbon dioxide, which is a foaming agent, in a molten molding material resin in a cylinder of a molding machine under high pressure, and then starting the material in a mold. This is a molding method in which a large number of fine bubbles are generated by rapidly reducing the pressure by injecting a resin.

  That is, the fine injection foam molding is a method for realizing the above-described fine foam molding in the injection molding process. The supercritical fluid generator pressurizes a gas that is a foaming agent to form a supercritical fluid (supercritical gas) and sends it out at a constant flow rate. The delivered fluid is adjusted to a pressure corresponding to the pressure in the cylinder of the molding machine and injected into the molding machine for a predetermined time. Specially designed cylinders and screws disperse the supercritical fluid as fine droplets in the molten resin, and subsequent mixing forms a single-phase solution with dissolved gases.

  When the injected single phase melt (raw material resin) passes through the nozzle of the molding machine or the valve gate of the mold, a large number of bubbles are generated and grow due to a rapid pressure drop. The bubbles stop growing when the resin pressure in the mold increases, or stop growing as the resin cools and solidifies.

<Supercritical gas>
The supercritical gas is a state of a substance having both gas fluidity and liquid solubility, and has high gas diffusivity and liquid solubility, and can be highly dissolved and highly dispersed in the molten resin. When the molten resin is injected into the mold, the pressure of the resin is rapidly reduced and the gas dissolved in the molten resin becomes supersaturated and rapidly becomes bubbles starting from the crystal nucleus.

  In the present invention, the supercritical gas specifically includes carbon dioxide and nitrogen. In the present invention, nitrogen is preferable because finer foam cells can be formed.

  This supercritical gas is injected into the cylinder of the injection molding machine by applying pressure from the injector.

<Molding conditions>
As a method for producing a fine foam molded article, any method may be used that includes a step of allowing a supercritical gas to permeate a resin composition that is a molding material (a step of making it compatible) and a step of degassing the molding material that has penetrated the gas. The method described in, for example, U.S. Pat. No. 4,473,665 and U.S. Pat. No. 5,158,986 can be used, and a desired fine foam molded article can be obtained by the following method. It can be manufactured efficiently.

  In a preferred production method, first, a supercritical gas is infiltrated into the resin composition. The gas used in this case is not particularly limited as long as it can be dissolved in the resin composition and is inert, and carbon dioxide or nitrogen is preferable, and more preferably, from the viewpoint of safety, cost, and the like. Nitrogen. Alternatively, carbon dioxide and nitrogen may be used in combination. This critical gas is infiltrated and compatible with 0.1 to 20 parts by mass, preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the resin composition. If the amount of supercritical gas is less than 0.1 parts by mass, homogeneous foamed cells are not formed, and the foaming ratio is not so high. On the other hand, when the amount exceeds 20 parts by mass, the appearance of the surface of the fine foamed molded product is deteriorated, and it is difficult to obtain a beautiful surface appearance, and this causes the generation of coarse foamed cells.

  In the present invention, the supercritical gas is preferably permeated into the molten resin composition in a molding machine cylinder during a metering process (also referred to as plasticization / metering process). Examples thereof include a method of injecting the inert gas in the state directly or under pressure or reduced pressure, a method of injecting the inert gas in the liquid state with a plunger pump or the like.

  Here, the metering step is a step of metering the molding resin necessary for the next molding shot by rotating the screw in the cylinder in the injection molding. When supercritical gas is allowed to permeate into the resin composition, the gas pressure must be maintained above the critical pressure of the gas to be permeated, at least until the introduction step into the mold is completed, and the permeation rate is further improved. For this purpose, it is preferably 15 MPa or more, particularly preferably 20 MPa or more.

  Next, the resin composition impregnated with the supercritical gas in this way is injected and filled into a mold and foamed. That is, by injecting and filling the molten resin from the cylinder into the mold, the resin is decompressed and the gas dissolved in the supersaturated state in the resin is foamed to form fine foam cells. If the supercritical state cannot be maintained before the resin composition impregnated with the supercritical gas is injected and filled into the mold, foaming is difficult and silver streaks are caused.

  After the resin composition impregnated with the supercritical gas is filled in the mold, the pressure in the mold is rapidly decreased while at least a part of the resin composition in the mold is in a molten state. A large number of foam nuclei are formed, and foam cells grow around them to obtain a high-transfer, high-gloss fine foam molded article having uniform foam cells. As a method of rapidly lowering the pressure in the mold, (1) the mold clamping pressure is relaxed, (2) the mold before filling the molding material impregnated with the supercritical gas is filled with 1 An inert gas of about ˜20 MPa is filled, and immediately after the molding material is introduced, the inert gas is removed. (3) The mold temperature is rapidly lowered. (4) The resin material in the mold is a mold. For example, the surface layer in contact with the mold forms a skin layer, and a part or all of the mold is retracted while the inside is in a molten state.

  Among these, it is particularly preferable to perform the operation (4). In the operation of (4), the average foamed cell diameter tends to be somewhat larger by retreating the mold at the above timing (core back), but the foamed cell diameter distribution is reduced, especially in the vicinity of the gate. As a result, the variation in the diameter of the foamed cell at the end of the molded body is reduced. What is necessary is just to select the ratio which reverse | retreats a metal mold | die according to the foaming ratio required. The expansion ratio is usually about 1.1 to 3 times. As a mechanism for retracting the mold, a known injection molding or injection compression molding mold unit can be used. Here, the core back uses a mold having a variable cavity volume. When filling the foamable molten resin, the cavity volume is reduced and the cavity volume is increased after filling. This is a method for promoting the generation and expansion of bubbles.

<Foamed cell>
In the present invention, as described above, the molten resin composition is injected and filled into a mold, and the resin is decompressed, whereby the gas dissolved in the resin is foamed to form fine foam cells. To do. At this time, the resin (B) forming the island phase becomes the starting point of foaming. Therefore, in order to make the particle diameter of the fine foam cell fine and uniform, when the resin (B) that forms the island phase that is the starting point of foaming is melted and kneaded in the injection molding machine, the number average particle It is necessary to be dispersed in the form of particles having a diameter of 10 μm or less.

<Method for Measuring Number Average Particle Size of Resin (B) Forming Island Phase>
Evaluation device: Scanning electron microscope “JSM-7401F” (manufactured by JEOL Ltd.)
Evaluation sample: (section thickness 100 to 200 nm)
Acceleration voltage: 30 kV
Magnification: 5000 times (Measurement sample preparation method and identification method for particle size of island phase)
[Method of preparing sample for measuring particle size of island phase]
Using a microtome “Ultra Cut E” (manufactured by Finetech Co., Ltd.) equipped with diamond teeth, a flaky sample having a thickness of 100 to 200 nm is cut out from an unfoamed molded body.

[Identification method]
The resin component in the molded body is identified based on the following criteria.

-Observed dark: Polyester, polyolefin, polyamide-Observed bright: Polycarbonate resin (Measurement of number average particle size of island phase)
Evaluation device: Image processing analysis device “LUZEX (registered trademark) AP” (manufactured by Nireco Corporation)
〔Measuring method〕
The particle diameters of 50 island phases are measured from the transmission microscope image.

  The number average particle diameter of the island phase is calculated as the average value of the horizontal ferret diameter. Here, the horizontal ferret diameter refers to the length of a side parallel to the x-axis of the circumscribed rectangle when the scanning electron microscope image is binarized.

<Method for measuring the number average cell diameter of foamed cells>
Evaluation device: Laser microscope “VK9510” (manufactured by Keyence Corporation)
Evaluation sample: Foam molded body Magnification: 200 times [Method for preparing cell diameter measurement sample]
JIS K7110 (1999) notched specimen-shaped foamed molded product is cooled with liquid nitrogen. The cooled unfoamed molded product is set in a universal impact tester (manufactured by Yasuda Seiki Seisakusho) and destroyed with a hammer. The obtained debris is used as a sample for cross-sectional observation.

(Measurement of number average cell diameter of foamed cells)
Evaluation device: Image processing analysis device “LUZEX (registered trademark) AP” (manufactured by Nireco Corporation)
〔Measuring method〕
50 cell diameters are measured from a 200-fold image of the laser microscope.

  The cell diameter of the foam cell is calculated as an average value of the horizontal ferret diameter. Here, the horizontal ferret diameter refers to the length of a side parallel to the x axis of the circumscribed rectangle when the laser microscope image is binarized.

<Use of the fine foam molded article of the present invention>
The polyester resin composition of the present invention can be molded into a desired shape by injection molding, and can be suitably used particularly for automobile parts, electronic / electric parts, office equipment for office use and the like.

  Examples of automotive parts include alternator terminals, alternator connectors, IC regulators, light meter potentiometer bases, air intake nozzle snorkels, intake manifolds, air flow meters, air pumps, fuel pumps, engine coolant joints, thermostat housings, carburetors Main body, carburetor spacer, engine mount, ignition hobbin, ignition case, clutch bobbin, sensor housing, idle speed control valve, vacuum switching valve, ECU housing, vacuum pump case, inhibitor switch, rotation sensor, acceleration sensor, distributor cap, Coil base, ABS actuator Case, radiator tank top and bottom, cooling fan, fan shroud, engine cover, cylinder head cover, oil cap, oil pan, oil filter, fuel cap, fuel strainer, distributor cap, vapor canister housing, air cleaner housing, timing belt Covers, brake booster parts, various cases, various tubes for fuel / exhaust / intake systems, various tanks, various hoses for fuel / exhaust / intake systems, various clips, various valves such as exhaust gas valves, various Pipe, exhaust gas sensor, cooling water sensor, oil temperature sensor, brake pad wear sensor, brake pad wear sensor, throttle position sensor, crankshaft port Sensor, air conditioner thermostat base, air conditioner panel switch board, heating hot air flow control valve, brush holder for radiator motor, water pump impeller, turbine vane, wiper motor related parts, step motor rotor, brake piston, solenoid bobbin, engine oil Filter, Ignition case, Torque control lever, Starter switch, Starter relay, Safety belt parts, Door lock housing, Door lock parts such as door lock protector, Register blade, Washer lever, Wind regulator handle, Wind regulator handle knob, Passing Light lever, distributor, sun visor bracket, motor housing , Roof rail, fender, garnish, bumper, door mirror stay, horn terminal, window washer nozzle, spoiler, hood louver, wheel cover, wheel cap, grill apron cover frame, lamp reflector, lamp socket, lamp housing, lamp bezel, door handle And various connectors such as wire harness connectors, SMJ connectors, PCB connectors, door grommet connectors, and fuse connectors.

  Examples of electronic / electrical components include connectors, coils, various sensors, LED lamps, sockets, resistors, relay cases, small switches, coil bobbins, capacitors, variable capacitor cases, optical pickups, oscillators, various terminal boards, and transformers. Instrument, plug, printed circuit board, tuner, speaker, microphone, headphones, small motor, magnetic head base, power module, semiconductor, liquid crystal, FDD carriage, FDD chassis, motor brush holder, parabolic antenna, computer-related parts, generator, electric motor , Transformers, current transformers, voltage regulators, rectifiers, inverters, relays, power contacts, switches, circuit breakers, knife switches, other pole rods, electrical parts cabinets, VTR parts, TV parts, irons, hair dryers, Cooked rice Parts, microwave oven parts, acoustic parts, audio equipment parts such as audio / laser disc (registered trademark) / compact disc / DVD, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, word processor parts, office computer parts, telephone -Related parts, mobile phone-related parts, facsimile-related parts, copying machine-related parts, cleaning jigs, motor parts, lighters, typewriter-related parts, microscopes, binoculars, cameras, watches and other optical equipment / precision machine-related parts, etc. Is mentioned.

  Examples of office equipment for office use include copiers, printer exterior parts, developer parts, toner container parts, paper feeder parts, and image forming unit parts.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
The materials used in the following examples and comparative examples are as follows.

(1) PC1: Polycarbonate “Taflon A-1900” (manufactured by Idemitsu Kosan Co., Ltd.)
(2) PC2: Polycarbonate “Iupilon H-2000” (Mitsubishi Engineering Plastics Co., Ltd.)
(3) Polyester 1: Polyester “Dianite MA521H-D25” (manufactured by Mitsubishi Rayon Co., Ltd.)
(4) Polyester 2: Polyester “Toraycon 4210X10” (manufactured by Toray Industries, Inc.)
(5) Polyolefin: “Prime Polypro J704UG” (manufactured by Prime Polymer Co., Ltd.)
(6) Polyamide: “Amilan CM3001” (manufactured by Toray Industries, Inc.)
(7) ABS: ABS resin “Toyolac 700-314” (manufactured by Toray Industries, Inc.)
(8) PS: Polystyrene “Toyostyrene GPMW2C” (manufactured by Toyo Styrene Co., Ltd.)
(9) Filler: Talc “MICRO ACE P-6” (manufactured by Nippon Talc Co., Ltd.)

<Preparation of Resin Composition 1>
100 parts by mass of polycarbonate “Taflon A-1900” (manufactured by Idemitsu Kosan Co., Ltd.) and 30 parts by mass of polyester “Dianite MA521 H-D25” (manufactured by Mitsubishi Rayon Co., Ltd.) were premixed using a double cone mixer. The mixture was melted and kneaded in a twin-screw extrusion kneader “KTX-30” (manufactured by Kobe Steel). Melting and kneading conditions were performed at a cylinder temperature of 260 ° C. and a screw rotation speed of 250 rpm.

  The molten resin composition obtained as described above was cooled and solidified, and chopped using a pelletizer to obtain a pellet-shaped resin composition 1 suitable as a resin material used in injection molding. .

<Preparation of Resin Compositions 2-15>
In the production of the resin composition 1, the resin composition (A), the resin (B) that constitutes the island phase, and the kneading conditions as described in Table 1 are the same as in the resin composition 2 15 was produced.

<Preparation of unfoamed molded body 1>
After the resin composition 1 produced as described above was dried at 80 ° C. for 4 hours, an injection molding machine “J140AD-110H Mucell specification” (manufactured by Nippon Steel Works) was used for JIS K7110 (1999). A test piece of an unfoamed molded body 1 having an equivalent shape (length 80 mm × width 10 mm × thickness 4 mm) for impact test, weight reduction rate measurement, and island phase number average particle size measurement was obtained. The molding conditions were a cylinder temperature (molding temperature) of 260 ° C., a mold temperature of 50 ° C., an injection molding speed of 30 mm / sec, and a holding pressure of 80 MPa.

<Preparation of unfoamed molded bodies 2-15>
Resin compositions 2 to 15 were used, and the non-foamed molded body 2 to 15 were prepared in the same manner as the unfoamed molded body 1 except that the molding conditions were set forth in Table 2. It used for evaluation of the weight reduction rate and the number average particle diameter of an island phase.

About the unfoamed molded objects 1-15 produced as mentioned above, the sea island state was observed.
≪Evaluation method≫
<Observation of sea island state>
As an alternative to the measurement of the number average particle size of the island phase in the molten and kneaded state in the injection molding machine of the resin compositions 1 to 15, the unfoamed molded products 1 to 15 were sliced with a microtome, and the scanning transmission electron microscope “JSM” The number average particle size of the island phase was measured as described above using “-7401F” (manufactured by JEOL Ltd.). The results are shown in Table 3.

(Evaluation criteria)
◎: Sea island structure, number average particle size of island phase is 5μm or less ○: Sea island structure, number average particle size of island phase is larger than 5μm, 10μm or less △: Sea island structure The number average particle size of the island phase is larger than 10 μm. ×: No sea island structure

<Preparation of fine foam molded article 1>
Using the same molding conditions and the same mold as the production of the unfoamed molded product, nitrogen in a supercritical state is 0.3% by mass with respect to the resin mass in the molding machine cylinder during the injection molding weighing process, and the injection pressure is 17 MPa. Injected. Molding was performed at a cylinder temperature of 260 ° C., a mold temperature of 50 ° C., an injection speed of 30 mm / sec, and a holding pressure of 0 MPa to produce a fine foam molded body 1.

<Preparation of fine foamed molded products 2-16>
In the production of the fine foam injection-molded body 1, fine foam molded bodies 2 to 16 were produced in the same manner except that the resin composition, supercritical gas and molding conditions were as shown in Table 4.

The fine foam molded bodies 1 to 16 produced as described above were evaluated as follows.
≪Evaluation method≫
<Observation of foaming state>
The number average cell diameter of the foamed cells was measured as described above using the laser microscope “VK9510” (manufactured by Keyence Co., Ltd.) as the foamed state of the fine foamed molded products 1-16.

(Evaluation criteria)
A: The number average cell diameter of the foamed cells is 5 μm or less. ○: The number average cell diameter of the foamed cells is larger than 5 μm and not more than 10 μm. Δ: The number average cell diameter of the foamed cells is larger than 10 μm and not more than 20 μm. Diameter greater than 20μm <Impact strength test>
The non-foamed molded products 1-15 produced using the fine foamed molded products 1-16 and the resin compositions 1-15 corresponding thereto were subjected to an impact strength test having a shape according to JIS K7110 (1999).

(Shock test method)
Evaluation device: Universal impact testing machine (manufactured by Yasuda Seiki Seisakusho)
Test piece shape: JIS K7110 Test piece with notch Test method: Izod Weight: 5.5J
The impact strength was measured as described above, and the impact strength reduction rate was determined by the following equation (1).

Formula (1):
[Impact Strength Reduction Rate] (%) = {([Impact Strength of Unfoamed Molded Product] − [Impact Strength of Fine Foamed Molded Product]) / [Impact Strength of Unfoamed Molded Product]} × 100
(Evaluation criteria)
◎: Impact strength reduction rate 10% or less ○: Impact strength reduction rate> 10% to 50% or less △: Impact strength reduction rate> 50% to 90% or less ×: Impact strength reduction rate> 90% <weight reduction>
About the unfoamed molded products 1-15 produced using the fine foamed molded products 1-16 and the resin compositions 1-15 corresponding thereto, the mass of one shot of the molded product is measured, and the weight is reduced by the following formula (2). The conversion rate was calculated.

Formula (2):
[Weight reduction ratio] (%) = {([1 shot mass of unfoamed molded article] − [1 shot mass of fine foamed molded article]) / [1 shot mass of unfoamed molded article]} × 100
(Evaluation criteria)
A: Lightening rate 10% or more B: Mildness rate 5% or more and less than 10% Δ: Lightening rate 3% or more and less than 5% ×: Lightening rate 3% or less The evaluation results described above are shown in Table 5.

  From the above results, the fine foam molded articles 1 to 9 of the present invention were superior in impact strength, weight reduction ratio and foamed state as compared with the molded articles 10 to 16 of the comparative examples. On the other hand, the molded body of the comparative example was inferior in any of the evaluation items.

  That is, the fine foamed molded article 10 did not add the resin (B) that forms the island phase, so the sea-island structure was not formed, foaming was not sufficient, and the impact strength was poor.

  Since the fine foamed molded article 11 used ABS resin as the resin (B) for forming the island phase, there was no generation start point of the fine foamed cells, the fine foamed cells became large, and the impact strength was inferior.

  The micro-foamed molded body 12 is obtained by adding PS as the resin (B) forming the island phase, but there is no origin of the micro-foamed cells, the micro-foamed cells become large, and the impact strength is inferior. .

  Since the amount of polyester, which is the resin (B) that forms the island phase, is small, the fine foam molded body 13 has a small foaming origin and therefore has a large fine foam cell and a low impact strength.

  The fine foam molded body 14 has a large amount of polyester added as the resin (B) forming the island phase, and therefore has many foaming origins. When the fine foam cells are bonded to each other, large foam cells are generated, resulting in impact strength. Was inferior.

  The fine foam molded body 15 uses talc as a filler instead of the resin (B) that forms the island phase, but the foamed state is good, but the weight reduction was not sufficient due to the filler. .

  Since the number average particle diameter of the island phase of the non-foamed molded body exceeded 10 μm, the microfoamed molded body 16 had a large microfoamed cell diameter.

A Resin that forms the sea phase (A)
B Resin that forms island phase (B)
C Fine foam cell

Claims (6)

A method for producing a microfoamed molded article having a sea-island structure comprising a continuous phase forming a sea phase and an independent phase forming an island phase, and having micro-foamed cells formed inside the island phase, the sea phase When the resin (A) that forms the resin contains polycarbonate and the content of the polycarbonate is 100 parts by mass, the resin (B) that forms the island phase is at least one selected from polyester, polyolefin, and polyamide. The manufacturing method of the fine foaming molding characterized by containing in the range of 10-60 mass parts, and forming through at least following process (1)-(4).
(1) Step of preparing a resin composition having a sea-island structure by kneading the resin (A) forming the sea phase and the resin (B) forming the island phase (2) Injection molding the resin composition Step of melting and kneading in a machine to disperse the resin (B) forming the island phase in the resin (A) forming the sea phase as a particulate matter having a number average particle size of 10 μm or less (3) Molten state A step of injecting a supercritical gas into the resin composition (4) a step of forming a fine foam cell inside the island phase in the molded body by injection molding the resin composition into which the supercritical gas has been injected.   The method for producing a fine foam molded article according to claim 1, wherein the resin (B) forming the island phase contains polyester.   The method for producing a fine foam molded article according to claim 1 or 2, wherein the supercritical gas is nitrogen gas. A micro-foamed molded article having a sea-island structure composed of a continuous phase forming a sea phase and an independent phase forming an island phase, and having micro-foamed cells formed inside the island phase, and forming the sea phase When the resin (A) contains a polycarbonate and the content of the polycarbonate is 100 parts by mass, the resin (B) forming the island phase is 10 to 60 at least one selected from polyester, polyolefin and polyamide. A fine foam molded article, which is contained within the range of part by mass and formed through at least the following steps (1) to (4).
(1) Step of preparing a resin composition having a sea-island structure by kneading the resin (A) forming the sea phase and the resin (B) forming the island phase (2) Injection molding the resin composition Step of melting and kneading in a machine to disperse the resin (B) forming the island phase in the resin (A) forming the sea phase as a particulate matter having a number average particle size of 10 μm or less (3) Molten state A step of injecting a supercritical gas into the resin composition (4) a step of forming a fine foam cell inside the island phase in the molded body by injection molding the resin composition into which the supercritical gas has been injected.   The fine foam molded article according to claim 4, wherein the resin (B) forming the island phase contains polyester.   6. The fine foam molded article according to claim 4, wherein the supercritical gas is nitrogen gas.

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