JP2005042045A - Polyester resin composition and molded product produced by molding the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition having enhanced heat resistance by the crystallization of a polylactic acid and excellent in handling during the molding process such that heat resistance of the polylactic acid is substantially enhanced by achieving the crystallization of the polylactic acid and the stabilization of the crystallinity and handling in the production of a molded product is improved by increasing the crystallization speed to shorten the removal time of the product from the mold during the molding process or the like and to provide a molded product. <P>SOLUTION: The resin composition is a polyester resin composition comprising 100 pts.mass polyester (AB) composed of 50-90 mass% biodegradable polyester resin (A) and 50-10 mass% polybutylene terephthalate resin (B) and 0.01-20 pts.mass (meth)acrylic ester compound (C). Additionally, the resin composition includes a polyester resin composition further comprising a phyllosilicate (D) blended into the above-described resin composition. The molded product includes a molded product produced by molding each of these polyester resin composition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a resin composition comprising a biodegradable polyester resin and a polybutylene terephthalate resin, and a molded article formed by molding the resin composition, and a petroleum-based product excellent in mechanical strength, heat resistance, and moldability. The present invention relates to a resin composition having a low dependence on the resin and a molded body molded using the same.

  In general, resins such as polypropylene (PP), ABS, polyamide (PA6, PA66), polyester (PET, PBT), and polycarbonate (PC) are used as raw materials for molding. However, moldings made from such resins are excellent in moldability and mechanical strength. However, when they are discarded, they increase the amount of dust and are hardly decomposed in the natural environment. However, it remains in the ground semipermanently. These resins are petroleum-based resins using petroleum as a starting material, and have a large environmental load during production.

On the other hand, in recent years, biodegradable polyester resins such as polylactic acid have attracted attention from the viewpoint of environmental conservation (for example, Patent Documents 1 and 2). Among the biodegradable resins, polylactic acid is one of the resins with the highest heat resistance, and can be mass-produced, so the cost is low and the utility is high. Furthermore, polylactic acid can be produced using plants such as corn and sweet potato as raw materials, and can contribute to saving depleted resources such as oil.
Japanese Patent Laid-Open No. 04-220456 Japanese Patent Laid-Open No. 08-193165

  However, even polylactic acid having high heat resistance among biodegradable resins did not have heat resistance enough to withstand actual use as compared with ABS, polyester and the like. Normally, heat resistance at a temperature of 50 to 70 ° C. is required indoors, and in vehicles such as cars, a temperature of 90 ° C. Considering safety during use, durability to an atmospheric temperature of 100 ° C. is realistic. It was necessary. By the way, in general, polylactic acid is a crystalline resin but has a low crystallization rate, and a normal molded product does not have high crystallinity, and therefore heat resistance is around 60 ° C. In order to improve heat resistance, (1) a crystal nucleating agent is added to polylactic acid to increase the crystallinity of polylactic acid. (2) Reinforcement is achieved by filling with inorganic filler and glass fiber. Has problems such as a long molding cycle and difficulty in stabilizing crystallinity, and has not been put into practical use. In addition, in (2), the apparent rigidity is increased by filling with a high specific gravity filler, and as a result, the heat resistance of the matrix polylactic acid itself is not increased, although some improvement in heat resistance is confirmed. The heat resistance level is insufficient.

  The present invention is intended to solve the above-described problems, and aims to improve the heat resistance of polylactic acid by crystallization of polylactic acid and stabilization of crystallinity. In addition, by increasing the crystallization speed, it is possible to shorten the take-out time of the product at the time of molding, etc., improving the handling on the production side, improving the heat resistance by crystallization of polylactic acid, and excellent at the time of molding It is in providing a resin composition and a molded object.

  As a result of intensive research to solve the above problems, the present inventors have found that a resin composition in which a biodegradable polyester resin and a polybutylene terephthalate resin are mixed in a specific range has heat resistance and handling during molding. As a result, the present invention has been found.

That is, the gist of the present invention is as follows.
(1) Biodegradable polyester resin (A) 50 to 90% by mass and polybutylene terephthalate resin (B) 50 to 10% by mass of polyester (AB) 100 parts by mass and (meth) acrylic acid ester compound (C ) A polyester resin composition containing 0.01 to 20 parts by mass.
(2) The polyester resin composition according to (1), further comprising 0.1 to 20 parts by mass of a layered silicate (D) per 100 parts by mass of the mixed polyester (AB).
(3) The polyester resin composition as described in (1) or (2) above, wherein the biodegradable polyester resin (A) is polylactic acid.
(4) A molded article obtained by molding the polyester resin composition according to any one of (1) to (3).

According to the present invention, a resin composition having excellent mechanical properties, heat resistance, and moldability and low dependence on petroleum products is provided. This resin composition can be applied to various molded articles, and since a biodegradable resin derived from a natural product is used, it can contribute to saving of depleted resources such as petroleum.

  Hereinafter, the present invention will be described in detail.

  The polyester resin composition of the present invention contains 50 to 90% by mass of the biodegradable polyester resin (A) and polyester (AB) composed of 50 to 10% by mass of the polybutylene terephthalate resin (B). Polyester (A) / polybutylene terephthalate (B) = 60-80% by mass / 40-20% by mass. When the blending amount of the polybutylene terephthalate resin (B) exceeds 50% by mass, it is difficult to say that it can contribute to saving of depleted resources such as petroleum because the ratio of petroleum-based raw materials is larger than that of raw materials derived from natural products. Further, when the blending amount of the biodegradable polyester resin exceeds 90% by mass and the blending amount of the polybutylene terephthalate resin is less than 10% by mass, sufficient heat resistance and moldability cannot be obtained.

  Examples of the biodegradable polyester resin of the present invention include poly (L-lactic acid), poly (D-lactic acid), polyglycolic acid, polycaprolactone, polybutylene succinate, and polyethylene succinate. Of these, poly (L-lactic acid), poly (D-lactic acid), and mixtures or copolymers thereof can be used from the viewpoints of heat resistance and moldability. From the viewpoint of biodegradability, poly (L-lactic acid) can be used. -Lactic acid) is preferred.

  Further, the melting point of polylactic acid mainly composed of poly (L-lactic acid) varies depending on the optical purity. However, in the present invention, the melting point is 160 ° C. or higher in consideration of the mechanical properties and heat resistance of the molded product. It is preferable that In order to obtain a melting point of 160 ° C. or higher in polylactic acid mainly composed of poly (L-lactic acid), the ratio of the D-lactic acid component may be less than about 3 mol%.

  The melt flow rate of the biodegradable polyester resin at 190 ° C. and a load of 21.2 N is 0.1 to 50 g / 10 minutes, preferably 0.2 to 20 g / 10 minutes, more preferably 0.5 to 10 g / 10 minutes. is there. When the melt flow rate exceeds 50 g / 10 min, the melt viscosity is too low, and the mechanical properties and heat resistance of the molded product are inferior. When the melt flow rate is less than 0.1 g / 10 min, the load during the molding process becomes too high and the operability may be lowered.

  The biodegradable polyester resin is usually produced by a known melt polymerization method or by further using a solid phase polymerization method. As a method for adjusting the melt flow rate of the biodegradable polyester resin to a predetermined range, when the melt flow rate is too large, a small amount of chain extender, for example, a diisocyanate compound, a bisoxazoline compound, an epoxy compound, an acid The method of increasing the molecular weight of resin using an anhydride etc. is mentioned. On the contrary, when the melt flow rate is too small, a method of mixing with a biodegradable polyester resin or a low molecular weight compound having a large melt flow rate can be mentioned.

  The polybutylene terephthalate resin (B) in the present invention is a thermoplastic polyester resin comprising a terephthalic acid component and a 1,4-butanediol component.

  In the polybutylene terephthalate resin (B), isophthalic acid, orthophthalic acid, chlorophthalic acid, nitrophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2 as long as the effects of the present invention are not impaired. , 7-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, methyl terephthalic acid, 4,4′-biphenyl dicarboxylic acid, 2,2′-biphenyl dicarboxylic acid, 4,4′-biphenyl ether dicarboxylic acid, 4,4 Aromatics such as' -diphenylmethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 4,4'-diphenylisopropylidenedicarboxylic acid, 1,2-bis (4-carboxyphenoxy) ethane, 5-sodium sulfoisophthalic acid, etc. Dicarboxylic acid, oxalic acid, succinic acid, adipic acid Suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, octadecanedicarboxylic acid, dimer acid, maleic acid, aliphatic dicarboxylic acid such as fumaric acid, alicyclic dicarboxylic acid such as 1,4-cyclohexanedicarboxylic acid, etc. are copolymerized May be.

  As diol components, ethylene glycol, propylene glycol, 1,3-butanediol, diethylene glycol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10- Aliphatic diols such as decanediol, alicyclic diols such as 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, bisphenols such as bisphenol A and bisphenol S, or their An aromatic diol such as an ethylene oxide adduct, hydroquinone, or resorcinol may be copolymerized.

  Furthermore, polybutylene terephthalate resin (B) includes p-hydroxybenzoic acid, p- (2-hydroxyethoxy) benzoic acid, hydroxycarboxylic acids such as 6-hydroxycaproic acid, δ-valerolactone, γ-butyrolactone, A lactone compound such as ε-caprolactone may be copolymerized. Moreover, an organic phosphorus compound may be copolymerized in order to impart flame retardancy.

  The polybutylene terephthalate resin (B) includes other polyester resins such as polyethylene terephthalate, polycyclohexylenedimethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate / terephthalate, polybutylene isophthalate / terephthalate, poly Polyethylene terephthalate / cyclohexylene dimethylene terephthalate, cyclohexylene dimethylene isophthalate / terephthalate, poly (p-hydroxybenzoic acid / ethylene terephthalate), polytetramethylene terephthalate composed of plant-derived raw material 1,3-propanediol, etc. It may be mixed.

In addition, thermoplastic elastomers such as styrene elastomers, olefin elastomers, urethane elastomers, and polyester elastomers can be used for the purpose of improving impact resistance. Elastomers are preferred.

  The intrinsic viscosity of the polybutylene terephthalate resin (B) is preferably 0.50 dl / g or more, and more preferably 0.70 to 1.20 dl / g. When the intrinsic viscosity is less than 0.50 dl / g, the mechanical strength when formed into a molded product is lowered. On the other hand, when the relative viscosity exceeds 1.20 dl / g, the moldability is lowered, which is not preferable.

  The melting point of the polybutylene terephthalate resin (B) is preferably 230 ° C. or less in the mixing with the biodegradable polyester resin (A), and the polybutylene terephthalate resin having a melting point of 190 to 225 ° C. has a kneading processing temperature. And a good mixture can be obtained.

  The polyester resin composition of the present invention needs to further contain a (meth) acrylic acid ester compound (C) in addition to the above (A) and (B). By this component, the polyester resin component is cross-linked, and mechanical strength and heat resistance are improved, and dimensional stability is also improved. The (meth) acrylic acid ester compound has high reactivity with the biodegradable resin, it is difficult for the monomer to remain, its toxicity is relatively low, and the resin is less colored, so there are two or more (meth) acrylic compounds in the molecule. Compounds having a group or having one or more (meth) acryl groups and one or more glycidyl groups or vinyl groups are preferred. Specific compounds include glycidyl methacrylate, glycidyl acrylate, glycerol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, allyloxy polyethylene glycol monoacrylate, allyloxy polyethylene glycol monomethacrylate, polyethylene glycol dimethacrylate, polyethylene glycol. Diacrylate, polypropylene glycol dimethacrylate, polypropylene glycol diacrylate, polytetramethylene glycol dimethacrylate, and these alkylene glycols may be copolymers of alkylenes of various lengths, but also butanediol methacrylate, butanediol acrylate, etc. Can be mentioned.

  The compounding amount of the (meth) acrylic ester compound (C) is 0.01 to 20 parts by mass with respect to 100 parts by mass of the mixed polyester (AB) of the polyester resin (A) and the polyester resin (B). Preferably it is 0.05-10 mass parts, More preferably, it is 0.1-5 mass parts.

  In blending the (meth) acrylic acid ester compound (C), it is preferable to use a peroxide in combination because the crosslinking reaction is promoted. Specific examples of peroxides include benzoyl peroxide, bis (butylperoxy) trimethylcyclohexane, bis (butylperoxy) cyclododecane, butylbis (butylperoxy) valerate, dicumyl peroxide, butylperoxybenzoate, dibutyl Examples thereof include peroxide, bis (butylperoxy) diisopropylbenzene, dimethyldi (butylperoxy) hexane, dimethyldi (butylperoxy) hexyne, and butylperoxycumene. As for the compounding quantity of a peroxide, 0.1-20 mass parts is preferable with respect to 100 mass parts of mixed polyester (AB), More preferably, it is 0.1-10 mass parts. Although it can be used even if it exceeds 20 parts by mass, it is disadvantageous in terms of cost. In addition, since such a peroxide decomposes | disassembles at the time of mixing with resin, even if it is used at the time of a mixing | blending, it may not be contained in the obtained resin composition.

  As a means for blending the (meth) acrylic acid ester compound (C) into the mixed polyester (AB), a method of melt kneading using a general extruder can be mentioned. In order to improve the kneading state, it is preferable to use a twin screw extruder. The kneading temperature is preferably in the range of (melting point of biodegradable polyester resin (A) + 5 ° C.) to (melting point of biodegradable polyester resin (A) + 100 ° C.), and the kneading time is preferably 20 seconds to 30 minutes. If the temperature is lower or shorter than this range, kneading or reaction becomes insufficient, and if the temperature is higher or longer, the resin may be decomposed or colored. At the time of blending, a (meth) acrylic acid ester compound or a method of supplying it using a dry blend or a powder feeder if solid is preferable, and in the case of a liquid, using a pressurizing pump, The method of injecting from is preferable. A peroxide can be blended in the same manner.

  As a preferable method when the (meth) acrylate compound and the peroxide are used in combination, a method in which the (meth) acrylate compound and / or the peroxide is dissolved or dispersed in a medium and injected into a kneader. As a result, the operability can be remarkably improved. That is, during the melt kneading of the mixed polyester resin component and the peroxide, a solution or dispersion of the (meth) acrylic acid ester compound is injected, or during the melt kneading of the polyester resin, the (meth) acrylic acid ester A solution or dispersion of a compound and a peroxide can be injected and melt kneaded.

  As a medium for dissolving or dispersing the (meth) acrylic ester compound and / or peroxide, a general one is used, and is not particularly limited, but a plasticizer excellent in compatibility with the polyester resin composition of the present invention. Is preferred. For example, one or more selected from aliphatic polycarboxylic acid ester derivatives, aliphatic polyhydric alcohol ester derivatives, aliphatic oxyester derivatives, aliphatic polyether derivatives, aliphatic polyether polycarboxylic acid ester derivatives, etc. Examples include plasticizers. Specific examples of the compound include dimethyl adipate, dibutyl adipate, triethylene glycol diacetate, methyl acetyl ricinoleate, acetyl tributyl citric acid, polyethylene glycol, and dibutyl diglycol succinate. As a usage-amount of a plasticizer, 30 mass parts or less are preferable with respect to 100 mass parts of mixed polyester resin (AB), and 0.1-20 mass parts is still more preferable. When the reactivity of the crosslinking agent is low, it is not necessary to use the plasticizer, but when the reactivity is high, it is preferable to use 0.1 parts by mass or more. In addition, since this medium may volatilize at the time of mixing with resin, even if it uses it at the time of manufacture, this medium may not be contained in the obtained resin composition.

  By including the layered silicate (D) in the polyester resin composition of the present invention, mechanical strength and heat resistance can be further improved. It is preferable that the compounding quantity shall be 0.1-20 mass parts with respect to 100 mass parts of mixed polyester resin (AB), More preferably, it is 0.2-10 mass parts. Specific examples of the layered silicate include smectite, vermiculite, and swellable fluorine mica. Examples of smectites include montmorillonite, beidellite, hectorite, and saponite. Examples of swellable fluorine mica include Na-type fluorine tetrasilicon mica, Na-type teniolite, Li-type teniolite, etc. In addition to the above, aluminum and magnesium such as kanemite, macatite, magadiite, and kenyaite are not included. Layered silicates can also be used. These layered silicates may be natural products or synthetic products. The synthetic product may be produced by any method such as a melting method, an intercalation method, or a hydrothermal method. These layered silicates may be used alone or in combination of two or more types having different mineral types, production areas, production methods, particle sizes and the like.

  The layered silicate is preferably pretreated with an organic cation. Examples of the organic cation include ammonium ions generated by protonation of primary to tertiary amines, onium ions such as quaternary ammonium ions and phosphonium ions. Examples of the primary amine include octylamine, dodecylamine, octadecylamine and the like. Examples of secondary amines include dioctylamine, methyloctadecylamine, and dioctadecylamine. Examples of the tertiary amine include trioctylamine, dimethyldodecylamine, didodecylmonomethylamine and the like. Examples of quaternary ammonium ions include tetraethylammonium, octadecyltrimethylammonium, dimethyldioctadecylammonium, dihydroxyethylmethyloctadecylammonium, methyldodecylbis (polyethyleneglycol) ammonium, methyldiethyl (polypropyleneglycol) ammonium and the like. Furthermore, examples of the phosphonium ion include tetraethylphosphonium, tetrabutylphosphonium, hexadecyltributylphosphonium, tetrakis (hydroxymethyl) phosphonium, 2-hydroxyethyltriphenylphosphonium, and the like. Of these, treatment with ammonium ions having one or more hydroxyl groups in the molecule, such as dihydroxyethyl methyl octadecyl ammonium, methyl dodecyl bis (polyethylene glycol) ammonium, methyl diethyl (polypropylene glycol) ammonium, 2-hydroxyethyl triphenylphosphonium, etc. The layered silicate is particularly preferable because it has a high affinity with a polyester resin, particularly a biodegradable polyester resin, and the dispersibility of the layered silicate is improved. These cations may be used alone or in combination of two or more.

  In addition, as a method of treating the layered silicate with the organic cation, first, the layered silicate is dispersed in water or alcohol, and the organic cation is added in the form of a salt to the layered silicate, thereby stirring the layered silicate. Examples of the method include ion-exchange of salt inorganic ions with organic onium ions, followed by filtration, washing, and drying.

  When layered silicate is used, a compatibilizing agent may be used in order to improve dispersibility in the polyester resin. The addition amount is preferably 0.01 to 10 parts by mass, more preferably 0.02 to 5 parts by mass with respect to 100 parts by mass of the mixed polyester resin (AB). If it exceeds 10 parts by mass, the heat resistance and mechanical strength of the biodegradable polyester resin composition may be lowered. As the compatibilizing agent, compounds such as polyalkylene oxide, aliphatic polyester, polyhydric alcohol ester, polyhydric carboxylic acid ester having affinity with both polyester resin, especially biodegradable polyester resin and layered silicate are used. It is done. Examples of polyalkylene oxides include polyethylene glycol, polypropylene glycol, polybutylene glycol, and copolymers thereof, one or two of the terminal hydroxyl groups may be alkoxy-capped, and may be monocarboxylic acid or dicarboxylic acid. It may be esterified with an acid. Examples of aliphatic polyesters include polylactic acid, polyglycolic acid, poly (3-hydroxybutyric acid), poly (3-hydroxyvaleric acid), poly (3-hydroxycaproic acid) and other polyhydroxycarboxylic acids, poly (ε -Caprolactone), poly (ω-hydroxyalkanoate) represented by poly (δ-valerolactone), poly (ethylene succinate), poly (butylene succinate), poly (butylene succinate-co-butylene adipate), etc. And aliphatic polyesters composed of a diol and a dicarboxylic acid represented by In these aliphatic polyesters, the terminal carboxyl group may be esterified with an alcohol or may be hydroxyl-substituted with a diol. Examples of the polyhydric alcohol ester include glycerin esters such as monoglyceride, diglyceride and triglyceride which are esters of glycerin and fatty acid, pentaerythritol ester and the like. Examples of polyvalent carboxylic acid esters include citric acid esters such as tributyl citrate and tributyl citrate.

  The compatibilizing agent preferably has a boiling point of 250 ° C. or higher. When the boiling point is less than 250 ° C., gas generation during molding and bleeding out from the obtained molded product may occur. The number average molecular weight is preferably in the range of 200 to 50,000, more preferably 500 to 20,000. When the molecular weight is less than 200, gas generation during molding and bleed out from the resulting molded product are likely to occur, and the mechanical strength and heat resistance of the molded product may be impaired. When the molecular weight exceeds 50,000, the effect of improving the dispersibility of the layered silicate tends to be small.

  As a method for adding a compatibilizing agent, a method of impregnating the above compound directly into a layered silicate in advance, a method of mixing the above compound in the presence of water or an organic solvent, and then removing water or the organic solvent by filtration or the like, a polyester resin And a method of adding together with a layered silicate at the time of synthesizing a polyester resin, etc., but prior to mixing with the polyester, a method of mixing the layered silicate in advance Is preferably used.

  When a layered silicate is added to the polyester resin composition of the present invention, a preferable dispersion state thereof is a complete delamination type in which each layer of the layered silicate is separated one by one, or an interlayer insertion in which resin molecules are inserted between layers. There are types, or a mixture of these types. Quantitatively, it is preferable that the average thickness of the single layer or laminated layer of a layered silicate observed with a transmission electron microscope is 1 to 100 nm, more preferably 1 to 50 nm, and still more preferably 1 to 20 nm. Alternatively, the interlayer distance of the layered silicate observed by X-ray diffraction is preferably 2.5 nm or more, more preferably 3 nm or more, still more preferably 4 nm or more, and most preferably a peak derived from the interlayer distance. Is not observed. Examples of the method for controlling the dispersibility of the layered silicate include, in the kneading method, change of kneading conditions, use of the compatibilizer described above, introduction of polar groups into the resin, and the like. In general, when a layered silicate is added during polymerization of polyester, dispersibility can be further improved.

  In the polyester resin composition of the present invention, glass fibers may be used in addition to the layered silicate for the purpose of improving mechanical strength and heat resistance. It is preferable that the compounding quantity shall be 1-50 mass parts with respect to 100 mass parts of mixed polyester resin (AB), 1-20 mass parts is more preferable, and 1-10 mass parts is further more preferable. The glass fiber may be subjected to a surface treatment in order to improve adhesion with the resin. As an addition method, it can be added from a hopper or in the middle of kneading using a side feeder in an extruder. Moreover, it can also use by diluting with a base resin at the time of shaping | molding by carrying out a masterbatch process of glass fiber.

  As long as the properties of the polyester resin composition of the present invention are not significantly impaired, pigments, heat stabilizers, antioxidants, weathering agents, flame retardants, plasticizers, lubricants, mold release agents, antistatic agents, fillers, A crystal nucleus material or the like can be added. Examples of heat stabilizers and antioxidants include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, and alkali metal halides. As the flame retardant, a halogen-based flame retardant, a phosphorus-based flame retardant, and an inorganic flame retardant can be used. However, in consideration of the environment, it is desirable to use a non-halogen flame retardant. Non-halogen flame retardants include phosphorus flame retardants, hydrated metal compounds (aluminum hydroxide and magnesium hydroxide), N-containing compounds (melamine and guanidine), and inorganic compounds (borate and Mo compounds). It is done. Inorganic fillers include talc, calcium carbonate, zinc carbonate, wollastonite, silica, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, carbon black, Examples thereof include zinc oxide, antimony trioxide, zeolite, hydrotalcite, metal fiber, metal whisker, ceramic whisker, potassium titanate, boron nitride, graphite, and carbon fiber. Examples of the organic filler include naturally occurring polymers such as starch, cellulose fine particles, wood flour, okara, fir shell, bran, and modified products thereof. Examples of the inorganic crystal core material include talc and kaolin. Examples of the organic crystal core material include a sorbitol compound, benzoic acid and a metal salt of the compound, a phosphate metal salt, and a rosin compound. In addition, the method of mixing these with the polyester resin composition of this invention is not specifically limited.

  The polyester resin composition of the present invention can be formed into various molded products by molding methods such as injection molding, blow molding, extrusion molding, inflation molding, and vacuum molding, pressure molding, and vacuum / pressure molding after sheet processing. In particular, it is preferable to adopt an injection molding method, and in addition to a general injection molding method, gas injection molding, injection press molding, and the like can be employed. As an example of injection molding conditions suitable for the resin composition of the present invention, the cylinder temperature is equal to or higher than Tm (the maximum value of the polyester resin (A) or (B)) or the flow start temperature of the polyester resin composition, preferably 190. It is appropriate that the temperature is in the range of -280 ° C, more preferably 210-270 ° C, and the mold temperature is (Tm-20 ° C) or less of the polyester resin composition. If the molding temperature is too low, the operability will become unstable, such as short-circuiting in the molded product, and it will easily fall into an overload. Conversely, if the molding temperature is too high, the polyester resin composition will decompose and the resulting molded product will Problems such as reduction in strength and coloring are likely to occur.

  The polyester resin composition of the present invention can enhance its heat resistance by promoting crystallization. As a method for this, for example, there is a method of promoting crystallization by cooling in a mold at the time of injection molding. In that case, the mold temperature is set to (Tg + 20 ° C.) or more of the polyester resin composition ( (Tm−20 ° C.) or less, and after maintaining for a predetermined time, it is preferable to cool to Tg or less. Further, as a method for promoting crystallization after molding, it is preferable to directly heat the sample at Tg or more and (Tm−20 ° C.) or less after cooling to Tg or less.

  Specific examples of molded articles using the polyester resin composition of the present invention include resin parts for electrical appliances such as PCs, mobile phones, and other office equipment housings, bumpers, instrument panels, console boxes, garnishes, door trims, ceilings. And resin parts for automobiles such as panels around the floor and engine. Moreover, it can also be set as a film, a sheet | seat, a hollow molded product, etc.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited only to an Example. The measuring method used for evaluation of the resin composition of an Example and a comparative example is as follows.
(1) Melt flow rate (MFR):
According to JIS standard K-7210 (test condition 4), it measured at 190 degreeC and the load 21.2N.
(2) Intrinsic viscosity (IV):
Measurement was performed at a temperature of 20 ° C. using a phenol / 1,1,2,2-tetrachloroethane mixed solvent (mass ratio 6/4).
(3) Formability:
An ASTM test dumbbell piece (thickness 3mmt) is molded with an injection molding machine at a cylinder temperature of 220 ° C and a mold temperature of 105 ° C, and can be easily removed without deformation when taken out from the mold. Was good, and those that deformed were considered bad. The molding cycle at this time was set to 250 seconds at the longest, and if the molded product could not be solidified or extracted without taking a longer time, the moldability was regarded as poor.
(4) Molding cycle:
During molding, when the molded product was extracted from the mold, the shortest time during which the molded product could be extracted without deformation was measured. The cycle was up to 250 seconds at the longest, and those that could not be solidified or removed from the molded product even if it took more time were not allowed.
(5) Thermal deformation temperature:
According to ASTM standard D-648, the heat distortion temperature was measured at a load of 0.45 MPa.
(6) Impact strength:
According to ASTM standard D-256, Izod impact strength was measured using a test piece with a notch (V-shaped cut).
(7) Flexural modulus:
In accordance with ASTM standard D-790, a load was applied at a deformation rate of 1 mm / min, and the flexural modulus was measured.

Moreover, the various raw materials used for the Example and the comparative example are as follows.
・ Polylactic acid (PLA):
NatureWorks 4030D by Cargill Dow; MFR = 3.0, melting point 166 ° C.
-Polybutylene terephthalate (PBT):
Mitsubishi Engineering Plastics 5010R5; IV = 0.85, melting point 225 ° C.
・ Polyethylene terephthalate (PET)
Unita MA-2101; IV = 0.64, melting point 255 ° C.
-Layered silicate (MEE):
Swellable synthetic fluorinated mica substituted with dihydroxyethylmethyldodecylammonium salt (Somasif MEE manufactured by Corp Chemical)
Methacrylic acid ester compound (PEGDM):
Polyethylene glycol dimethacrylate (Nippon Yushi)
・ Peroxide (DBPO):
Di-t-butyl peroxide (manufactured by NOF Corporation)
・ Plasticizer (ATBC):
Acetyltributylcitric acid / polyester elastomer (ELAS)
Hytrel 4057 (manufactured by Toray DuPont)
・ Glass fiber (GF)
GF-T187H (Nippon Electric Glass Co., Ltd.)
Example 1 (resin composition A)
Using a twin-screw extruder (Ikegai PCM-30, die diameter: 4 mm × 3 holes, extrusion head temperature: 250 ° C., die outlet temperature: 240 ° C.), 70 parts by mass of PLA and 30 parts by mass of PBT were supplied, and melt-kneaded extrusion At that time, a solution in which 1.0 part by mass of PEGDM and 1.0 part by mass of DBPO were dissolved in 2.5 parts by mass of ATBC was injected from the middle of the kneader using a pump. Then, the discharged resin was cut into pellets to obtain a resin composition A.
Example 2 (resin composition B)
The composition of the solution injected from the middle of the kneader was changed to 0.5 parts by mass of PEGDM, 0.5 parts by mass of DBPO, and 1.25 parts by mass of ATBC. Obtained.
Example 3 (resin composition C)
A resin composition C was obtained by performing the same operation as in Example 1 except that the composition of the solution poured from the middle of the kneader was 4.0 parts by mass of PEGDM, 4.0 parts by mass of DBPO, and 10 parts by mass of ATBC. .
Example 4 (resin composition D)
Resin composition D was obtained in the same manner as in Example 1 except that 1.0 part by mass of MEE was supplied together with 70 parts by mass of PLA and 30 parts by mass of PBT.
Example 5 (resin composition E)
Resin composition E was obtained in the same manner as in Example 1 except that, in addition to 70 parts by mass of PLA and 30 parts by mass of PBT, 4.0 parts by mass of MEE was supplied.
Example 6 (resin composition F)
Except that PLA was 50 parts by mass and PBT was 50 parts by mass, melt-kneading extrusion was performed in the same manner as in Example 1 to obtain a resin composition F.
Example 7 (resin composition G)
Except that PLA was 90 parts by mass and PBT was 10 parts by mass, melt-kneading extrusion was performed in the same manner as in Example 1 to obtain a resin composition G.
Example 8 (resin composition H)
Except for supplying 70 parts by mass of PLA and 30 parts by mass of PBT and further 10 parts by mass of ELAS, melt kneading extrusion was performed in the same manner as in Example 1 to obtain a resin composition H.
Example 9 (resin composition I)
Except for supplying 70 parts by mass of PLA and 30 parts by mass of PBT, and further supplying 5 parts by mass of ELAS and 5 parts by mass of GF, melt-kneading extrusion was performed in the same manner as in Example 1 to obtain a resin composition I.

  The evaluation results of Examples 1 to 9 are summarized in Table 1.

比較例１（樹脂組成物Ｊ）
二軸押出機（池貝製ＰＣＭ−３０、ダイス直径；４ｍｍ×３孔、押出ヘッド温度；２６０℃、ダイ出口温度；２４０℃）を用い、ＰＬＡ７０質量部、ＰＢＴ３０質量部を供給した。溶融混練押出した後、ペレット状に加工し、樹脂組成物Ｊを得た。
比較例２（樹脂組成物Ｋ）
ＰＬＡとＰＢＴのほかに、さらにＭＥＥ１質量部を用いた以外は比較例１と同様の操作を行って樹脂組成物Ｋを得た。
比較例３（樹脂組成物Ｌ）
原料としてＰＬＡを９５質量部、ＰＢＴを５質量部を用い、混練機途中からポンプを用いてＰＥＧＤＭを１．０質量部、ＤＢＰＯ１．０質量部、ＡＴＢＣ２．５質量部供給した以外は、比較例１と同様に溶融混練押出しを行い、樹脂組成物Ｌを得た。
比較例４（樹脂組成物Ｍ）
ＰＬＡを４０質量部、ＰＢＴを６０質量部、ＭＥＥ１質量部を用いた以外は、比較例１と同様に溶融混練押出しを行い、樹脂組成物Ｍを得た。
比較例５（樹脂組成物Ｎ）
原料として使用するＰＬＡを７０質量部、ＰＢＴに代えて、ＰＥＴを３０質量部供給した他は、実施例１と同様の操作を行って、樹脂組成物Ｎを得た。

Comparative Example 1 (resin composition J)
Using a twin screw extruder (Ikegai PCM-30, die diameter: 4 mm × 3 holes, extrusion head temperature: 260 ° C., die outlet temperature: 240 ° C.), 70 parts by mass of PLA and 30 parts by mass of PBT were supplied. After melt-kneading extrusion, it was processed into pellets to obtain a resin composition J.
Comparative Example 2 (resin composition K)
In addition to PLA and PBT, the same operation as in Comparative Example 1 was carried out except that 1 part by mass of MEE was used to obtain a resin composition K.
Comparative Example 3 (resin composition L)
Comparative Example, except that 95 parts by mass of PLA and 5 parts by mass of PBT were used as raw materials, and 1.0 part by mass of PEGDM, 1.0 part by mass of DBPO, and 2.5 parts by mass of ATBC were supplied from the middle of the kneader using a pump. In the same manner as in Example 1, melt-kneading extrusion was performed to obtain a resin composition L.
Comparative Example 4 (resin composition M)
Except that 40 parts by mass of PLA, 60 parts by mass of PBT, and 1 part by mass of MEE were used, melt-kneading extrusion was performed in the same manner as in Comparative Example 1 to obtain a resin composition M.
Comparative Example 5 (Resin Composition N)
Resin composition N was obtained in the same manner as in Example 1 except that 70 parts by mass of PLA used as a raw material and 30 parts by mass of PET were supplied instead of PBT.

  The results of Comparative Examples 1 to 5 are shown in Table 1.

  Resin compositions A to N obtained in Examples 1 to 9 and Comparative Examples 1 to 5 were molded using an injection molding machine (IS-80G type manufactured by Toshiba Machine) to obtain various test pieces. At this time, it was melted at a cylinder set temperature of 220 ° C., filled in a mold of 105 ° C. with an injection pressure of 100 MPa and an injection time of 20 seconds, and cooled for 60 seconds. However, Comparative Example 1 was molded at a mold temperature of 20 ° C. because it could not be molded at a mold temperature of 105 ° C. even with a cooling cycle of 250 seconds. For Comparative Example 5, the cylinder temperature was 250 ° C.

  Moreover, about resin composition AI obtained in Examples 1-9, the housing | casing for personal computers was produced using said same molding conditions. The obtained casing was not a problem in practical use.

  In each of Examples 1 to 9, a polylactic acid / polybutylene terephthalate resin composition excellent in moldability, shortening the molding cycle, and excellent in heat resistance, impact strength, flexural modulus and the like was obtained. Since it is mainly composed of a lactic acid component, it can be said that the composition has a high contribution to the environment.

  On the other hand, in Comparative Example 1, since the (meth) acrylic acid ester compound was not used, the impact strength was insufficient in terms of moldability, molding cycle, and heat resistance. Moreover, although the comparative example 2 is a case where layered silicate is mix | blended with the composition of the comparative example 1, although the moldability was improved, the molding cycle and heat resistance were inadequate. In Comparative Example 3, the moldability was good because of the large amount of polylactic acid, but the molding cycle was very long, and the heat resistance was insufficient. In Comparative Example 4, both processability and heat resistance were good, but since the proportion of polylactic acid is 50% by mass or less of the resin component, it is difficult to say that the material has a sufficiently high contribution to the environment. In Comparative Example 5, PET was used instead of PBT, but the heat resistance was slightly improved, but the moldability was inferior, the molding cycle was long, and the physical properties were insufficient.

Claims (4)

100 parts by mass of polyester (AB) comprising 50 to 90% by mass of biodegradable polyester resin (A) and 50 to 10% by mass of polybutylene terephthalate resin (B), and (meth) acrylic ester compound (C) 0. The polyester resin composition containing 01-20 mass parts. The polyester resin composition according to claim 1, further comprising 0.1 to 20 parts by mass of a layered silicate (D) per 100 parts by mass of the polyester (AB). The polyester resin composition according to claim 1 or 2, wherein the biodegradable polyester resin (A) is polylactic acid. The molded object formed by shape | molding the polyester resin composition in any one of Claims 1-3.