JP2011157538A - Resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition which can reduce an environmental load and is excellent in moldability, heat resistance and shock resistance while maintaining bending properties. <P>SOLUTION: The resin composition contains polylactic acid resin (A) and 5-sulfoisophthalic acid dimethyl metal salt (B), wherein the content of the polylactic acid resin (A) in the resin composition is 70 mass% or more and the content of the 5-sulfoisophthalic acid dimethyl metal salt (B) in the resin composition is 0.1 to 10 mass%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is capable of reducing an environmental load, maintains a bending characteristic, and is excellent in moldability, heat resistance and impact resistance, and a molded body formed by molding the resin composition It is about.

  Generally, as a raw material for molding, polypropylene resin (PP), acrylonitrile-butadiene-styrene resin (ABS resin), polyamide resin such as nylon 6 and nylon 66, polyester resin such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate resin, etc. Resin is used. A molded body produced from such a resin is excellent in mechanical strength such as moldability, impact resistance and bending characteristics. However, when it is discarded, there is a problem that the amount of waste is increased and it is hardly decomposed in the natural environment, so that it remains semi-permanently even if it is buried.

  On the other hand, in recent years, biodegradable polyester resins such as polylactic acid have attracted attention from the viewpoint of environmental conservation. Among the biodegradable polyester resins, polylactic acid, polyethylene succinate, polybutylene succinate and the like are low in cost and highly useful because they can be mass-produced. Among them, polylactic acid can already be produced from plants such as corn and sweet potato, and even if incinerated after use, it is neutral as a carbon balance considering the carbon dioxide absorbed during the growth of these plants. Therefore, in particular, it is a resin with a low load on the global environment.

  Polylactic acid is applicable to a wide range of applications because heat resistance is improved by sufficiently proceeding with crystallization. However, polylactic acid alone has a very slow crystallization rate. Therefore, for the purpose of improving the crystallization rate, addition of various crystallizing agents to polylactic acid, crosslinking of polylactic acid, and the like have been studied.

  As a technique for adding a crystal nucleating agent to promote crystallization of polylactic acid, it is known to add a carboxylic acid amide or ester having a specific molecular structure (Patent Document 1). As a technique for adding a crystal nucleating agent to promote crystallization of polylactic acid, it is known to add tricyclohexyltrimesic acid amide (Patent Document 2). Furthermore, it is known that ethylene bis-12-hydroxystearic acid amide is added as a technique for adding a crystal nucleating agent in order to promote crystallization of polylactic acid (Patent Document 3).

  As a technique for crosslinking polylactic acid in order to promote crystallization of polylactic acid, it is known to add a (meth) acrylic acid ester compound to polylactic acid (Patent Document 4). Moreover, compounding an isocyanate compound with polylactic acid is disclosed as a method of crosslinking polylactic acid in order to promote crystallization of polylactic acid (Patent Document 5).

  However, as described above, even if the crystal nucleating agent is added to polylactic acid or the polylactic acid is subjected to a crosslinking treatment, the effect of improving the crystallization rate is still insufficient. Therefore, when obtaining a molded body, for example, when it is subjected to injection molding, the molding cycle becomes long, so that the moldability is inferior compared to a molded body using a conventional resin. Moreover, it did not achieve heat resistance and impact resistance that could withstand practical use.

International Publication No. 2006/13797 Pamphlet JP 2006-328163 A JP 2003-226801 A JP 2003-128901 A Japanese Patent Laid-Open No. 2002-3709

  The present invention is intended to solve the above-mentioned problems, can reduce the environmental load, and maintains a bending characteristic while being excellent in moldability, heat resistance and impact resistance. Is intended to provide. Furthermore, it aims at providing the molded object which consists of this resin composition.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a resin composition containing a polylactic acid resin and dimethyl metal salt of 5-sulfoisophthalic acid. The invention has been reached.

That is, the gist of the present invention is as follows.
(1) A resin composition containing a polylactic acid resin (A) and a 5-sulfoisophthalic acid dimethyl metal salt (B), wherein the content of the polylactic acid resin (A) in the resin composition is 70% by mass or more The resin composition is characterized in that the content of dimethyl 5-sulfoisophthalate metal salt (B) in the resin composition is 0.1 to 10% by mass.
(2) The resin composition according to (1), wherein the polylactic acid resin (A) has a D-form content of 1.0 mol% or less, or 99.0 mol% or more.
(3) The resin composition of (1) or (2), wherein the polylactic acid resin (A) is crosslinked.
(4) Of the silane compounds (E) in which the polylactic acid resin (A) has two or more functional groups selected from (meth) acrylic acid ester compounds (D), alkoxy groups, acrylic groups, methacrylic groups, and vinyl groups At least any one compound is contained, The resin composition in any one of (1)-(3) characterized by the above-mentioned.
(5) The plasticizer (F) is contained in the resin composition, and the content of the plasticizer (F) in the resin composition is 0.1 to 15% by mass (1) The resin composition in any one of-(4).
(6) The plasticizer (F) is an aliphatic polyvalent carboxylic acid ester derivative, an aliphatic polyhydric alcohol ester derivative, an aliphatic oxyester derivative, an aliphatic polyether derivative, or an aliphatic polyether polyvalent carboxylic acid ester derivative. (5) Resin composition characterized by being at least one selected.
(7) The resin composition contains at least one reactive compound (G) selected from a carbodiimide compound, an epoxy compound, and an oxazoline compound, and the content of the reactive compound (G) in the resin composition is It is 0.1-10 mass%, The resin composition in any one of (1)-(6) characterized by the above-mentioned.
(8) A molded product obtained by molding the resin composition according to any one of (1) to (7).

  According to the present invention, it is possible to provide a polylactic acid-based resin composition having both moldability, heat resistance and impact resistance while maintaining bending characteristics, and having a low environmental load. By using this polylactic acid-based resin composition for a housing of an electrical product or the like, the use range of a polylactic acid resin, which is a low environmental load material, can be greatly expanded, and the industrial utility value is extremely high.

Hereinafter, the present invention will be described in detail.
The resin composition of the present invention contains a polylactic acid resin (A) and a 5-sulfoisophthalic acid dimethyl metal salt (B).

As the polylactic acid resin (A), poly (L-lactic acid), poly (D-lactic acid), and a mixture or copolymer thereof can be used.
In order to improve the moldability and the heat resistance of the resulting molded body, the polylactic acid resin (A) has a D-form content of 1.0 mol% or less, or a D-form content of 99, among others. It is preferably 0.0 mol% or more, more preferably 0.1 to 0.6 mol%, or even more preferably 99.4 to 99.9 mol%. When a polylactic acid resin having a D-form content outside this range is used, the resulting molded article has a low crystallinity and tends to be inferior in heat resistance and moldability.

  In the present invention, the D-form content of the polylactic acid resin (A) is a ratio (mol%) occupied by D-lactic acid units in the total lactic acid units constituting the polylactic acid resin. Therefore, for example, in the case of a polylactic acid resin having a D-form content of 1.0 mol%, the proportion of D-lactic acid units in the polylactic acid resin is 1.0 mol%, and the proportion of L-lactic acid units Is 99.0 mol%.

  In the present invention, the D-form content of the polylactic acid resin (A) is all methyl ester of L-lactic acid and D-lactic acid obtained by decomposing the polylactic acid resin (A), as described later in Examples. And is calculated by a method of analyzing the methyl ester of L-lactic acid and the methyl ester of D-lactic acid with a gas chromatography analyzer.

  Moreover, it is preferable that the melt flow rate (MFR) in 190 degreeC and load 21.2N of a polylactic acid resin (A) is 0.1-50 g / 10min, and it is 0.2-20 g / 10min especially. It is preferably 0.5 to 10 g / 10 min. If the MFR exceeds 50 g / 10 min, the melt viscosity is too low, and the mechanical properties and heat resistance when formed into a molded product may be inferior. Further, when the MFR is less than 0.1 g / 10 minutes, the load at the time of the molding process becomes high, so that the operability may be lowered. In addition, said MFR is the value measured by JISK7210 (test condition D).

  Further, as a method for controlling the MFR of the polylactic acid resin (A) within a predetermined range, when the MFR is too large, a small amount of chain extender, for example, a diisocyanate compound, a bisoxazoline compound, an epoxy compound, an acid anhydride, etc. And a method of increasing the molecular weight of the resin. Conversely, when the MFR is too small, a method of mixing with a polyester resin or a low molecular weight compound having a larger MFR can be mentioned.

The polylactic acid resin (A) is produced by a known melt polymerization method or by further using a solid phase polymerization method.
In the polylactic acid resin (A), monomers other than main constituent components may be copolymerized. Examples of the copolymerizable monomer include terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and 1,5 as acid components. -Naphthalenedicarboxylic acid, methyl terephthalic acid, 4,4'-biphenyl dicarboxylic acid, 2,2'-biphenyl dicarboxylic acid, 4,4'-biphenyl ether dicarboxylic acid, 4,4-diphenylmethane dicarboxylic acid, 4,4'- Aromatic dicarboxylic acids such as diphenylsulfone dicarboxylic acid and 4,4'-diphenylisopropylidenedicarboxylic acid; adipic acid, sebacic acid, oxalic acid, malonic acid, succinic acid, azelaic acid, undecanedioic acid, dodecanedioic acid, aikosan diacid Saturated aliphatic dicarboxylic acids such as acids and hydrogenated dimer acids; Unsaturated aliphatic dicarboxylic acids such as malic acid, maleic acid, itaconic acid, mesaconic acid, citraconic acid, and dimer acid and their anhydrides; 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2 -Cycloaliphatic dicarboxylic acid, 2,5-norbornene dicarboxylic acid, and alicyclic dicarboxylic acids such as tetrahydrophthalic acid.

  Examples of the copolymerizable monomer include ethylene glycol, propylene glycol, 1,3-butanediol, diethylene glycol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1,8 as diol components. Aliphatic diols such as octanediol and 1,10-decanediol; alicyclic diols such as 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol and 1,2-cyclohexanedimethanol, bisphenol A and bisphenol Bisphenols such as S or their ethylene oxide adducts; and aromatic diols such as hydroquinone and resorcinol.

  Furthermore, as copolymerizable monomers, hydroxycarboxylic acids such as p-hydroxybenzoic acid, p- (2-hydroxyethoxy) benzoic acid, 6-hydroxycaproic acid, 3-hydroxybutyric acid, and 3-hydroxyvaleric acid; -Lactone compounds such as valerolactone, γ-butyrolactone, and ε-caprolactone. Moreover, an organic phosphorus compound may be copolymerized in order to impart flame retardancy.

  The content of the polylactic acid resin (A) in the resin composition of the present invention needs to be 70% by mass or more, preferably 80% by mass or more, and more preferably 90% by mass or more. It is preferable. When the content of the polylactic acid resin (A) is less than 70% by mass, the effect of reducing the environmental load is poor, which is not preferable. The upper limit of the content of the polylactic acid resin (A) in the resin composition is 99.9% by mass in consideration of the content of other compounds such as 5-sulfoisophthalic acid dimethyl metal salt (B) described later. It is preferably at most 99% by mass, more preferably at most 98% by mass.

  The resin composition of the present invention contains 5-sulfoisophthalic acid dimethyl metal salt (B) as a crystal nucleating agent for the purpose of promoting crystallization of the polylactic acid resin (A) and improving impact resistance. It is necessary to. That is, in the present invention, by combining the polylactic acid resin (A) and a specific crystal nucleating agent, that is, dimethyl metal salt of 5-sulfoisophthalic acid (B), the impact resistance of the resin composition is improved and crystallization is performed. It is possible to express remarkable effects such as improvement of heat resistance by promotion and improvement of moldability.

  The content of 5-sulfoisophthalic acid dimethyl metal salt (B) needs to be 0.1 to 10% by mass in the resin composition of the present invention, preferably 1 to 10% by mass, more preferably 2 to 8% by mass. When the content is less than 0.1% by mass, the effect of improving heat resistance by promoting crystallization, the effect of improving moldability, and the effect of improving impact resistance are poor. On the other hand, if it exceeds 10% by mass, the effect as a crystal nucleating agent is saturated and not only economically disadvantageous, but also heat resistance may be lowered. Moreover, since the residue after biodegradation increases, it is not preferable also from an environmental viewpoint.

  Examples of the 5-sulfoisophthalic acid dimethyl metal salt (B) include dimethylbarium 5-sulfoisophthalate, dimethylpotassium 5-sulfoisophthalate, dimethylmagnesium 5-sulfoisophthalate, and dimethylsodium 5-sulfoisophthalate. Of these, dimethylbarium 5-sulfoisophthalate and dimethylpotassium 5-sulfoisophthalate are preferable from the viewpoint of molding cycle and impact resistance.

  In the present invention, in order to promote crystallization of the polylactic acid resin (A) and improve moldability and heat resistance, it is preferable to crosslink the polylactic acid resin (A) to obtain a crosslinked polylactic acid. Specifically, the polylactic acid resin (A) is a silane compound (E) having two or more functional groups selected from a (meth) acrylic acid ester compound (D), an alkoxy group, an acrylic group, a methacryl group, and a vinyl group. Among these, it is preferable to contain at least one of the compounds.

  As a method for obtaining such a crosslinked polylactic acid resin (A), the polylactic acid resin (A) is selected from (meth) acrylic acid ester compounds (D), alkoxy groups, acrylic groups, methacrylic groups, and vinyl groups. At least one compound of silane compound (E) having two or more functional groups (hereinafter sometimes simply referred to as “silane compound (E)”) is blended, and peroxide (C) is further added. A blending method is preferred. When a crosslinking agent other than the peroxide (C), the (meth) acrylic acid ester compound (D) and the silane compound (E) is used, the crosslinking efficiency is insufficient, so that the polylactic acid resin (A) In some cases, the effect of promoting crystallization cannot be fully expressed.

  The peroxide (C) is blended for the purpose of promoting crystallization of the resin composition. When used in combination with the (meth) acrylic acid ester compound (D) or the silane compound (E), the polylactic acid resin (A) and the (meth) acrylic acid ester compound (D) or the silane compound (E) The reaction can be promoted, and the moldability and heat resistance can be further improved.

In addition, since the peroxide (C) is decomposed and consumed during mixing with the resin, it may not remain in the obtained resin composition even when added during melt kneading.
Specific examples of the peroxide (C) include, for example, benzoyl peroxide, bis (butylperoxy) trimethylcyclohexane, bis (butylperoxy) cyclododecane, butylbis (butylperoxy) valerate, dicumyl peroxide, butyl Examples include peroxybenzoate, dibutyl peroxide, bis (butylperoxy) diisopropylbenzene, dimethyldi (butylperoxy) hexane, dimethyldi (butylperoxy) hexyne, and butylperoxycumene. These may be used alone or in combination of two or more. Can be used. Among these, di-t-butyl peroxide is preferable from the viewpoint of crosslinking efficiency.

  The compounding amount of the peroxide (C) is preferably 0.01 to 5 parts by mass and more preferably 0.05 to 3 parts by mass with respect to 100 parts by mass of the polylactic acid resin. If the blending amount is less than 0.01 parts by mass, the target moldability and heat resistance may not be obtained, and the impact resistance may decrease. On the other hand, if the blending amount exceeds 5 parts by mass, the operability during kneading may be reduced.

  The (meth) acrylic acid ester compound (D) is blended for the purpose of promoting crystallization of the resin composition. Since the (meth) acrylic acid ester compound (D) has high reactivity with the polylactic acid resin, the monomer hardly remains, the toxicity is small, and the coloring of the resin is small, two or more (meth) in the molecule. Compounds having an acrylic group or having one or more (meth) acrylic groups and one or more glycidyl groups or vinyl groups are preferred.

  Specific examples of (meth) acrylic acid ester compounds include glycidyl methacrylate, glycidyl acrylate, glycerol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, allyloxy polyethylene glycol monoacrylate, allyloxy (poly) ethylene glycol monomethacrylate. , (Poly) ethylene glycol dimethacrylate, (poly) ethylene glycol diacrylate, (poly) propylene glycol dimethacrylate, (poly) propylene glycol diacrylate, (poly) tetramethylene glycol dimethacrylate, or these alkylene glycol moieties Copolymers of alkylenes of various lengths, butanediol methacrylate, butanediol active Rate, and the like. Among the above, (poly) ethylene glycol dimethacrylate is particularly preferable from the viewpoints of crystallization promoting effect and heat resistance.

  The amount of the (meth) acrylic acid ester compound (D) is preferably 0.01 to 5 parts by mass and more preferably 0.05 to 3 parts by mass with respect to 100 parts by mass of the polylactic acid resin. preferable. If the blending amount is less than 0.01 parts by mass, the target moldability and heat resistance cannot be obtained, and if it exceeds 5 parts by mass, the operability during kneading may decrease.

  The silane compound (E) is blended for the purpose of promoting the crystallization of the resin composition, and is represented by the following formula (I).

式（Ｉ）中、Ｒ_１〜Ｒ_４の少なくとも２つ以上は、アルコキシ基、アクリル基、メタクリル基、ビニル基から選ばれる官能基を表す。残りは、アルコキシ基、ビニル基、アクリル基、メタアクリル基以外を表し、例えば水素、アルキル基、エポキシ基が挙げられる。

In formula (I), at least two of R _{1 to} R ₄ represent a functional group selected from an alkoxy group, an acrylic group, a methacryl group, and a vinyl group. The rest represents other than alkoxy groups, vinyl groups, acrylic groups, and methacrylic groups, and examples thereof include hydrogen, alkyl groups, and epoxy groups.

  Examples of the alkoxy group include a methoxy group and an ethoxy group. Examples of the vinyl group include a vinyl group and a p-styryl group. Examples of the acrylic group include a 3-methacryloxypropyl group and a 3-acryloxypropyl group. Examples of the alkyl group include a methyl group and an ethyl group. Examples of the epoxy group include a 3-glycidoxypropyl group and a 2- (3,4-epoxycyclohexyl) group.

  Specific examples of such silane compounds (E) and examples of trade names include tetramethoxysilane (trade name “TSL8114” manufactured by GE Toshiba Silicone, trade name “KBM-04” manufactured by Shin-Etsu Chemical Co., Ltd.), tetra Ethoxysilane (trade name “TSL8124” manufactured by GE Toshiba Silicone, product name “KBE-04” manufactured by Shin-Etsu Chemical Co., Ltd.), methyltrimethoxysilane (trade name “TSL8113” manufactured by GE Toshiba Silicone, Inc., product manufactured by Shin-Etsu Chemical Co., Ltd.) Name “KBM-13”), methyltriethoxysilane (trade name “TSL8123” manufactured by GE Toshiba Silicone, trade name “KBE-13” manufactured by Shin-Etsu Chemical Co., Ltd.), dimethyldimethoxysilane (trade name “GE Toshiba Silicone”) TSL8112 "), dimethyldiethoxysilane (GE Toshiba Silicone product name" SL8122 ", trade name" KBE-22 "manufactured by Shin-Etsu Chemical Co., Ltd.), methyldimethoxysilane (trade name" TSL8117 "manufactured by GE Toshiba Silicone), methyldiethoxysilane (trade name" TSL8127 "manufactured by GE Toshiba Silicone), Phenyltrimethoxysilane (trade name “TSL8173” manufactured by GE Toshiba Silicone), phenyltriethoxysilane (trade name “TSL8178” manufactured by GE Toshiba Silicone, product name “KBE-103” manufactured by Shin-Etsu Chemical Co., Ltd.), diphenyldimethoxysilane (Trade name “TSL8172” manufactured by GE Toshiba Silicone), diphenyldiethoxysilane (trade name “TSL8177” manufactured by GE Toshiba Silicone), hexyltrimethoxysilane (trade name “KBM-3063” manufactured by Shin-Etsu Chemical Co., Ltd.), decyl Trimethoxyshi Run (trade name “KBM-3103C” manufactured by Shin-Etsu Chemical Co., Ltd.), 3-glycidoxypropyldimethoxysilane (trade name “TSL-8355” manufactured by GE Toshiba Silicone), 3-glycidoxypropyltrimethoxysilane (GE) Product name “TSL-8350” manufactured by Toshiba Silicone Corp., product name “KBM-403” manufactured by Shin-Etsu Chemical Co., Ltd.), dimethylvinylmethoxysilane (product name “TSL8317” manufactured by GE Toshiba Silicone Corp.), methylvinyldimethoxysilane (GE Toshiba) Silicone product name “TSL8315”), methylvinyldiethoxysilane (GE Toshiba Silicone product name “TSL8316”), dimethylvinylethoxysilane (GE Toshiba Silicone product name “TSL8318”), vinyltrimethoxysilane ( Product name manufactured by Shin-Etsu Chemical Co., Ltd. KBM-1003 "), vinyltriethoxysilane (trade name" TSL8311 "manufactured by GE Toshiba Silicone, trade name" KBE-1003 "manufactured by Shin-Etsu Chemical Co., Ltd.), 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (Trade name “KBM-303” manufactured by Shin-Etsu Chemical Co., Ltd.), 3-glycidoxypropylmethyldiethoxysilane (trade name “KBE-402” manufactured by Shin-Etsu Chemical Co., Ltd.), p-styryltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.) Product name “KBM-1403”), 3-methacryloxypropylmethyldimethoxysilane (GE Toshiba Silicone product name “TSL8375”, Shin-Etsu Chemical Co., Ltd. product name “KBM-502”), 3-methacryloxypropyl Trimethoxysilane (trade name “TSL8370” manufactured by GE Toshiba Silicones Co., Ltd.) Shin-Etsu Chemical Co., Ltd., trade name “KBM-503”), 3-methacryloxypropylmethyldiethoxysilane (Shin-Etsu Chemical Co., Ltd., trade name “KBE-502”), 3-methacryloxypropyltriethoxysilane (Shin-Etsu Chemical) Product name “KBE-503”), 3-acryloxypropyltrimethoxysilane (trade name “KBM-5103” manufactured by Shin-Etsu Chemical Co., Ltd.), 3-acryloxypropylmethyldimethoxysilane (trade name manufactured by Shin-Etsu Chemical Co., Ltd.) “KBM-5102”) and the like.

  Among these, a silane compound (E) having one functional group selected from an acryl group, a methacryl group, and a vinyl group and having three alkoxy groups is preferable in terms of improving the crystallization speed. Specific examples of such silane compounds and examples of trade names include vinyltrimethoxysilane (trade name “KBM-1003” manufactured by Shin-Etsu Chemical Co., Ltd.), vinyltriethoxysilane (trade name “TSL8311” manufactured by GE Toshiba Silicone Co., Ltd.). , Shin-Etsu Chemical Co., Ltd., trade name “KBE-1003”), p-styryltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., trade name “KBM-1403”), 3-methacryloxypropyltrimethoxysilane (GE manufactured by Toshiba Silicone Co., Ltd.) Trade name “TSL8370”, trade name “KBM-503” manufactured by Shin-Etsu Chemical Co., Ltd.), 3-methacryloxypropyltriethoxysilane (trade name “KBE-503” manufactured by Shin-Etsu Chemical Co., Ltd.), 3-acryloxypropyltri Methoxysilane (trade name “KBM-5103” manufactured by Shin-Etsu Chemical Co., Ltd.) .

  It is preferable that the compounding quantity of a silane compound (E) is 0.01-5 mass parts with respect to 100 mass parts of polylactic acid resin, More preferably, it is 0.05-3 mass parts. If the blending amount is less than 0.01 parts by mass, the target moldability and heat resistance may not be obtained. On the other hand, if it exceeds 5 parts by mass, the operability during kneading may be reduced.

  The peroxide (C), the (meth) acrylic acid ester compound (D) and the silane compound (E) may be used alone, but from the viewpoint of promoting crystallization, two or more kinds are used in combination. It is preferable. Among them, [peroxide (C) and (meth) acrylic ester compound (D)], [peroxide (C) and silane compound (E)], [peroxide (C) and (meth) acrylic. More preferably, the acid ester compound (D) and the silane compound (E)] are used in combination. As a crosslinking agent, the peroxide (C), the (meth) acrylic acid ester compound (D), and the silane compound (E) are used in such a combination to shorten the molding cycle of the polylactic acid resin (A), By reducing the burrs, it is possible to improve the formability and to obtain a remarkable effect that heat resistance can be improved.

  When two or more peroxides (C), (meth) acrylic acid ester compounds (D), and silane compounds (E) are used in combination, the total amount is 0. 0 parts by mass relative to 100 parts by mass of the polylactic acid resin. It is preferable that it is 02-8 mass parts, More preferably, it is 0.1-3.5 mass parts. If the total blending amount is less than 0.02 parts by mass, the above effects may not be obtained. On the other hand, if it exceeds 8 parts by mass, the operability during kneading may be reduced.

  The resin composition of the present invention preferably contains a plasticizer (F). Although it does not specifically limit as a plasticizer (F), The thing excellent in compatibility with a polylactic acid resin (A) is preferable. For example, at least one 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. Is mentioned. By using such a plasticizer (F), moldability and heat resistance can be improved.

  Specific examples of the plasticizer (F) include glycerol diacetomonolaurate, glycerol diacetomonocaprate, polyglycerol acetate, polyglycerol fatty acid ester, medium chain fatty acid triceride, dimethyl adipate, dibutyl adipate, and triethylene glycol diester. Examples include acetate, methyl acetyl ricinoleate, acetyl tributyl citrate, polyethylene glycol, dibutyl diglycol succinate, bis (butyl diglycol) adipate, bis (methyl diglycol) adipate, and adipic acid ester.

  Specific examples of the names of plasticizers (F) include the product names “PL-102”, “PL-109”, “PL-320”, “PL-710”, “Actor series (M-1, M) manufactured by Riken Vitamin Co., Ltd. -2, M-3, M-4, M-107FR) "; Taoka Chemical Co., Ltd. trade name" ATBC "; Daihachi Chemical Co., Ltd. trade names" DAIFATTY-101 "" BXA "" MXA "; Taiyo Chemical Co., Ltd. The trade name “Tirabazole Series (VR-01, VR-05, VR-10P, VR-10P Rev. 1, VR-623)” and the like may be mentioned.

  The content of the plasticizer (F) in the resin composition of the present invention is preferably 0.1 to 15% by mass, and more preferably 1 to 15% by mass. If the content is less than 0.1% by mass, the effect of improving moldability and heat resistance may be poor. On the other hand, when it exceeds 15 mass%, heat resistance may fall and a plasticizer (F) may bleed out on the surface.

  Furthermore, the resin composition of the present invention preferably contains a reactive compound. By including a compound having reactivity, the durability of the resin composition can be improved and the heat resistance can be stably maintained for a long period of time. In the present invention, the reactive compound is at least one reactive compound (G) selected from a carbodiimide compound, an epoxy compound, and an oxazoline compound [hereinafter sometimes referred to as a reactive compound (G)]. Is preferred.

  Various compounds can be used as the carbodiimide compound, and there are no particular limitations as long as it has one or more carbodiimide groups in the molecule. Examples of the carbodiimide compound include aliphatic monocarbodiimide, aliphatic polycarbodiimide, alicyclic monocarbodiimide, alicyclic polycarbodiimide, aromatic monocarbodiimide, aromatic polycarbodiimide, and the like. Furthermore, you may have various heterocyclic rings or various functional groups in a molecule | numerator.

  As the carbodiimide compound, a carbodiimide compound having an isocyanate group in the molecule and a carbodiimide compound having no isocyanate group in the molecule can be used without distinction.

  As a carbodiimide skeleton of the carbodiimide compound, N, N′-di-o-triylcarbodiimide, N, N′-dioctyldecylcarbodiimide, N, N′-di-2,6-dimethylphenylcarbodiimide, N-triyl-N '-Cyclohexylcarbodiimide, N-triyl-N'-phenylcarbodiimide, N, N'-di-p-nitrophenylcarbodiimide, N, N'-di-p-hydroxyphenylcarbodiimide, N, N'-di-cyclohexylcarbodiimide N, N′-di-cyclohexylcarbodiimide, N, N′-di-p-triylcarbodiimide, p-phenylene-bis-di-o-triylcarbodiimide, 4,4′-dicyclohexylmethanecarbodiimide, tetra Methylxylylene carbodiimide, N, N′-dimethyl Le phenyl carbodiimide, N, etc. N'- di-2,6-diisopropylphenyl carbodiimide, include many carbodiimide skeleton.

  Specific examples of the carbodiimide compound include many compounds. Examples of the alicyclic monocarbodiimide include dicyclohexylcarbodiimide. Examples of the alicyclic polycarbodiimide include polycarbodiimide derived from 4,4'-dicyclohexylmethane diisocyanate. Examples of the aromatic monocarbodiimide include N, N′-diphenylcarbodiimide, N, N′-di-2,6-diisopropylphenylcarbodiimide, and the like. Examples of the aromatic polycarbodiimide include polycarbodiimide derived from phenylene-p-diisocyanate, polycarbodiimide derived from 1,3,5-triisopropyl-phenylene-2,4-diisocyanate, and the like. Said carbodiimide compound can be used individually or in combination of 2 or more types.

In polycarbodiimide, both ends of the molecule or any part in the molecule may have a functional group such as an isocyanate group or are different from other sites such as branched molecular chains. It may have a molecular structure.
It does not specifically limit as a method of manufacturing a carbodiimide compound, Many methods, such as the method of manufacturing an isocyanate compound as a raw material, are mentioned.

As the epoxy compound, for example, an epoxy compound containing bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether or the like is most preferable.
As the oxazoline compound, an oxazoline compound containing 2-isopropenyl-2-oxazoline is most preferable.

  The content of the reactive compound (G) in the resin composition of the present invention (the total content when a plurality of compounds are used) is preferably 0.1 to 10% by mass, and preferably 0.5 to 5%. More preferably, it is mass%. If the content is less than 0.1% by mass, the intended durability (moisture heat resistance) may not be obtained. On the other hand, if the content exceeds 10% by mass, the heat resistance is lowered, it is not economically preferable, and the color tone may be greatly impaired.

  The melt flow rate (value according to JIS K-7210 (test condition 4)) at 190 ° C. and a load of 21.2 N of the resin composition of the present invention is preferably 0.1 to 30 g / 10 min. More preferably, it is 2 to 20 g / 10 minutes, and further preferably 0.5 to 10 g / 10 minutes. When the melt flow rate exceeds 30 g / 10 min, the melt viscosity is too low, and the obtained molded product may have poor mechanical properties and heat resistance. On the other hand, when the melt flow rate is less than 0.1 g / 10 minutes, the load during the molding process is increased, which is not preferable because the operability is lowered and the cost is increased.

  As a method for controlling the MFR of the resin composition within a predetermined range, when the MFR is too large, a small amount of chain extender such as a diisocyanate compound, a bisoxazoline compound, an epoxy compound, an acid anhydride or the like is used. A method for increasing the molecular weight is mentioned. Conversely, when the MFR is too small, a method of mixing with a polyester resin or a low molecular weight compound having a larger MFR can be mentioned.

  The method for producing the resin composition of the present invention is not particularly limited as long as each component is uniformly dissolved or dispersed. For example, after uniformly dry blending using a tumbler or Henschel mixer, melt kneading and extrusion may be performed, followed by cooling, cutting, and drying steps to form pellets. In melt kneading, a general kneader such as a single screw extruder, a twin screw extruder, a roll kneader, or a Brabender can be used.

  When mixing polylactic acid resin (A) with 5-sulfoisophthalic acid dimethyl metal salt (B), plasticizer (F) and reactive compound (G), or when making crosslinked polylactic acid resin (A) The means for melt-kneading the polylactic acid resin with the peroxide (C), the (meth) acrylic ester compound (D), the silane compound (E), etc. is not particularly limited. For example, a uniaxial or biaxial extruder The method of melt-kneading using can be mentioned. Among these, it is preferable to use a twin screw extruder in order to improve the kneading state. The kneading temperature is preferably {[melting point of polylactic acid resin (A)] + 5} ° C. to {[melting point of polylactic acid resin (A)] + 100} ° C. When the temperature is lower than this range, kneading and reaction become insufficient. On the other hand, when the temperature is higher than this range, the resin may be decomposed or colored. The kneading time is preferably 20 seconds to 30 minutes. If the time is shorter than this time, the kneading or reaction becomes insufficient. On the other hand, if it is longer than this time, the resin may be decomposed or colored.

  When a plasticizer (F) is further added to the resin composition containing the polylactic acid resin (A) and 5-sulfoisophthalic acid dimethyl metal salt (B), the polylactic acid resin (A), 5-sulfoisophthalate It is preferable to supply the acid dimethyl metal salt (B) and the plasticizer (F) simultaneously from the top feeder of the extruder so that they are sufficiently compatible or dispersed.

In order to make polylactic acid resin (A) into cross-linked polylactic acid, when compounding peroxide (C) with polylactic acid resin, it is preferable to mix when polylactic acid resin is in a molten state, and therefore an extruder It is preferable to supply from the middle of the barrel. As a preferable method in the case of supplying the peroxide (C) from the middle of the barrel, from the viewpoint of significantly improving the operability, there is a method in which the peroxide (C) is dissolved or dispersed in a medium and injected into a kneader. Can be mentioned. The medium for dissolving or dispersing the peroxide (C) is not particularly limited, and a general medium can be used. Among them, a plasticizer excellent in compatibility with the polylactic acid resin (A) is preferable, and if the peroxide (C) is dissolved or uniformly dispersed, the same plasticizer (F) as described above is used. You may use different things. Two or more plasticizers may be used in combination.
From the viewpoint of crosslinking efficiency, the mass ratio of the peroxide (C) and the medium is preferably [peroxide (C)] :( medium) = 1: 3 to 1:10. 7 is more preferable.

  When the polylactic acid resin (A) is cross-linked polylactic acid, when the (meth) acrylic acid ester (D) or the silane compound (E) is added to the polylactic acid resin, the polylactic acid resin and dimethyl 5-sulfoisophthalate Along with the metal salt (B), it may be added from the top feeder, or after polylactic acid resin is blended with (meth) acrylic acid ester (D) or silane compound (E) to obtain polylactic acid resin (A) Further, dimethyl metal 5-sulfoisophthalate (B) may be added.

  In the resin composition of the present invention, as long as the properties are not impaired, pigments, heat stabilizers, antioxidants, inorganic fillers, plant fibers, reinforcing fibers, weathering agents, lubricants, mold release agents, antistatic agents, Additives other than the above-mentioned crystal nucleating agent, such as an impact resistance agent and a compatibilizing agent, can be added.

Examples of the pigment include titanium and carbon black.
Examples of heat stabilizers and antioxidants include hindered phenols, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and the like.

  Examples of the inorganic filler include talc, mica, calcium carbonate, zinc carbonate, wollastonite, alumina, magnesia, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, carbon black, Examples include zinc oxide, antimony trioxide, zeolite, hydrotalcite, metal fiber, metal whisker, ceramic whisker, potassium titanate, boron nitride, graphite, carbon fiber, and layered silicate. Especially, the gas barrier property of a resin composition can be improved by mix | blending layered silicate.

Examples of plant fibers include kenaf fibers, bamboo fibers, jute fibers, and other cellulosic fibers.
Examples of reinforcing fibers include organic reinforcing fibers such as aramid fibers, polyarylate fibers, and liquid crystal polymer fibers.

Examples of weathering agents include benzotriazole and benzoxazinone.
As the lubricant, various carboxylic acid compounds can be used, and among them, various fatty acid metal salts, particularly magnesium stearate and calcium stearate are preferable.

As the mold release agent, various carboxylic acid compounds, particularly, various fatty acid esters, various fatty acid amides, and the like are preferably used.
It does not specifically limit as an impact-resistant agent, Various things, such as a (meth) acrylic ester-type impact-resistant agent which has a core-shell type structure, can be used. A commercially available impact-resistant agent can also be suitably used, and examples thereof include “Metablene Series” manufactured by Mitsubishi Rayon Co., Ltd.

  Although it does not specifically limit as a compatibilizing agent, For example, the graft copolymer which has an olefin type copolymer resin in a principal chain is mentioned. Specific examples include poly (ethylene / glycidyl methacrylate) -polymethyl methacrylate graft copolymer, poly (ethylene / glycidyl methacrylate) -poly (acrylonitrile / styrene) graft copolymer, and the like. As the compatibilizing agent, commercially available products can also be suitably used, and examples thereof include “Modiper Series” manufactured by NOF Corporation.

The method for mixing the above-mentioned additives into the resin composition of the present invention is not particularly limited.
A resin other than the polylactic acid resin (A) can be mixed with the resin composition of the present invention to make an alloy.

  The resin to be alloyed with the resin composition of the present invention is not particularly limited. For example, polyolefin, polyester, polyamide, polycarbonate, polystyrene, poly (methyl) methacrylate, poly (acrylonitrile-butadiene-styrene) copolymer, Examples thereof include liquid crystal polymers and polyacetals.

Examples of the polyolefin include polyethylene and polypropylene.
Examples of the polyamide include polyamide 6, polyamide 66, polyamide 610, polyamide 11, polyamide 12, and polyamide 6T.

  Examples of polyester include various aromatic polyesters and various aliphatic polyesters. Specific examples of the aromatic polyester include polyethylene terephthalate, polybutylene terephthalate, polyarylate, and polybutylene adipate terephthalate. Specific examples of the aliphatic polyester include polybutylene succinate, poly (butylene succinate-lactic acid) copolymer, and polyhydroxybutyric acid.

  Other polyester compounds include polycyclohexylene dimethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate terephthalate, polybutylene isophthalate terephthalate, polyethylene terephthalate / cyclohexylene dimethylene terephthalate, cyclohexene. Examples thereof include xylene dimethylene isophthalate choterephthalate, copolyester composed of p-hydroxybenzoic acid residue and ethylene terephthalate residue, polytrimethylene terephthalate composed of 1,3-propanediol which is a plant-derived raw material.

The method of mixing these resins with the resin composition of the present invention is not particularly limited.
The resin composition of the present invention can be produced by various methods such as injection molding, blow molding, extrusion molding, inflation molding, injection blow molding, foam sheet molding, and vacuum molding, pressure molding, vacuum pressure molding and the like after sheet processing. It can be set as a molded body. That is, a molded body formed by injection molding, or a film or sheet formed by extrusion molding, a molded body formed by processing these films or sheets, or a hollow body formed by blow molding, and from this hollow body It can be set as the molded object etc. which are processed. Among the above, it is particularly 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 also be employed.

  If an example of the injection molding conditions suitable for the resin composition of this invention is given, it will be preferable that the cylinder temperature shall be more than melting | fusing point or flow start temperature of a resin composition, for example, 170-250 degreeC, and it shall be 170-230 degreeC. It is more preferable. The mold temperature is suitably (melting point of the resin composition−40) ° C. or lower. If the molding temperature is too lower than the above-mentioned range of the cylinder temperature or the mold temperature, a short circuit may occur in the molded product, which may cause the operability to become unstable or easily fall into an overload. On the other hand, if the molding temperature is too high exceeding the above-mentioned cylinder temperature or mold temperature range, the resin composition will decompose, causing problems such as reduction in the strength of the resulting molded product or coloring. It is easy to do and may not be preferable.

  The resin composition of the present invention can further improve heat resistance by promoting crystallization during molding. As a method of promoting crystallization, for example, there is a method of promoting crystallization in a mold at the time of injection molding. In that case, the glass transition temperature of the resin composition or higher (melting point −40 of the resin composition) A method in which the molded body is held for a certain period of time in a mold kept at a temperature of 0 ° C. or lower and then taken out from the mold is suitable. Further, even if the molded body is taken out from the mold without taking such a method, the molded body is heat-treated at a temperature not lower than the glass transition temperature of the resin composition and not higher than (melting point of the resin composition −40) ° C. By doing so, crystallization can be promoted.

  Specific examples of the molded body using the resin composition of the present invention include personal computer casing parts and casings, mobile phone casing parts and casings, other OA equipment casing parts, and resin parts for electrical appliances such as connectors. ; Resin parts for automobiles such as bumpers, instrument panels, console boxes, garnishes, door trims, ceilings, floors, panels around engines, agricultural materials such as containers and cultivation containers, and resin parts for agricultural machinery; Resin parts for marine products such as food containers; dishes and food containers such as dishes, cups, spoons; medical resin parts such as syringes and infusion containers; houses, civil engineering, and drainage materials, fences, storage boxes, construction switchboards, etc. Resin parts for building materials; Resin parts for greening materials such as flowerbed bricks and flower pots; Resin parts for leisure and miscellaneous goods such as cooler boxes, fan fans and toys; Balls Down, ruler, stationery for the resin parts such as clips and the like.

  Among them, the resin composition of the present invention is particularly useful in parts that require bending characteristics, moldability, heat resistance and impact resistance.

Hereinafter, the present invention will be described more specifically with reference to examples. The measuring methods used for the evaluation of the resin compositions of Examples and Comparative Examples are as follows.
(1) D-form content of polylactic acid resin (A) 0.3 g of the obtained resin composition was weighed, added to 6 mL of 1N potassium hydroxide / methanol solution, and sufficiently stirred at 65 ° C. Subsequently, 450 μL of sulfuric acid was added and stirred at 65 ° C. to decompose polylactic acid, and 5 mL was measured as a sample. To this sample, 3 mL of pure water and 13 mL of methylene chloride were mixed and shaken. After stationary separation, about 1.5 mL of the lower organic layer was collected, filtered through a HPLC disk filter having a pore size of 0.45 μm, and then subjected to gas chromatography measurement using HP-6890 Series GC system manufactured by Hewlett Packard. The ratio (%) of the peak area of D-lactic acid methyl ester to the total peak area of lactic acid methyl ester was calculated, and this was defined as the D-form content (mol%) of the polylactic acid resin (A).

(2) Polylactic acid resin (A), melt flow rate (MFR) of resin composition Measured according to JIS K 7210 (test conditions D) at 190 ° C. and a load of 21.1 N.
(3) Bending strength The bending strength was measured according to ISO178 using the obtained test piece. In the present invention, a material having a bending strength of 90 MPa or more can be practically used.

(4) Bending elastic modulus Using the obtained test piece, the bending elastic modulus was measured according to ISO178. In the present invention, a material having a flexural modulus of 3.1 GPa or more can be practically used.

(5) Impact resistance Charpy impact strength measured according to ISO 179-1 was used using the obtained test piece. In the present invention, those having a Charpy impact strength of 3.5 kJ / m ² or more are assumed to withstand practical use.

(6) Heat resistance Using the obtained test piece, the deflection temperature under load measured at a load of 0.45 MPa was used according to ISO75-1. In the present invention, those having a deflection temperature under load of 95 ° C. or more are assumed to be practically usable.

(7) Formability (molding cycle)
Using the obtained pellets (after vacuum drying at 70 ° C. for 24 hours), an ISO dumbbell-shaped test piece was molded with an injection molding machine (trade name “IS-80G” manufactured by Toshiba Machine Co., Ltd.). The resin composition was melted at a molding temperature of 190 ° C. and filled into a mold having a mold temperature of 85 ° C. When the resin composition is injected into the mold, the total of the injection time and the time when pressure is applied after injection is 30 seconds, and then the molded body can be fixed to the mold or taken out without resistance, The total time (molding cycle) (seconds) with the time required to release the mold without any deformation due to the protruding pin was measured and evaluated according to the following criteria.
A: Required time is 60 seconds or less.
○: The required time is longer than 60 seconds and not longer than 80 seconds.
X: The required time exceeds 80 seconds.
In the present invention, those having a value of ◯ or more are assumed to be practically usable.

(8) Durability (Bending strength retention)
Two test pieces obtained were prepared, and one was measured for bending strength by the same method as in (3) above. The other was subjected to a wet heat treatment by exposure for 500 hours in an environment of a temperature of 60 ° C. and a humidity of 95 ° C. RH, and the bending strength (bending strength after the wet heat treatment) was measured again by the same method as (3) above. The bending strength retention was calculated from the following formula.
(Bending strength retention) (Unit:%) = (Bending strength after wet heat treatment) / (Bending strength before wet heat treatment) × 100
Evaluation was made according to the following criteria.
A: Bending strength retention is 85% or more.
○: Bending strength retention is 60% or more and less than 85%.
X: Bending strength retention is less than 60%.
In the present invention, a material having a bending strength retention rate of 60% or more (evaluation is ◯ or more) can be practically used.

Moreover, the various raw materials used for the Example and the comparative example are as follows.
(1) Polylactic acid resin, manufactured by Cargill Dow, trade name “Nature Works 3001D” (MFR: 10 g / 10 min, melting point: 168 ° C., D-form content: 1.4 mol%) (hereinafter referred to as “3001D”) May be)
・ Product name “S-12” (manufactured by Toyota Motor Corporation) (MFR: 8 g / 10 min, melting point: 178 ° C., D-form content: 0.1 mol%) (hereinafter sometimes referred to as “S-12”)
・ Product name “S-06” (manufactured by Toyota Motor Corporation) (MFR: 4 g / 10 min, melting point: 176 ° C., D-form content: 0.2 mol%) (hereinafter sometimes referred to as “S-06”)
・ Product name “A-1” (manufactured by Toyota Motor Corporation) (MFR: 2 g / 10 min, melting point: 172 ° C., D-form content: 0.6 mol%) (hereinafter sometimes referred to as “A-1”)
(2) 5-sulfoisophthalic acid dimethyl metal salt (B)
(B-1): Dimethyl barium 5-sulfoisophthalate (manufactured by Takemoto Yushi Co., Ltd., trade name “LAK-403”)
-(B-2): Dimethyl potassium 5-sulfoisophthalate (manufactured by Takemoto Yushi Co., Ltd., trade name "LAK-301")
(3) Crystal nucleating agent other than dimethyl metal salt of 5-sulfoisophthalic acid (B) (B-3): Octanedicarboxylic acid dibenzoylhydrazide (trade name “T-1287A” manufactured by Adeka)
-(B-4): Zinc phenylphosphonate (manufactured by Nissan Chemical Co., Ltd., trade name "Eco Promote NP")
(4) Peroxide (C)
Di-t-butyl peroxide (manufactured by NOF Corporation, “Perbutyl D”) (hereinafter sometimes referred to as “PBD”)
(5) (Meth) acrylic acid ester compound (D)
・ Ethylene glycol dimethacrylate (manufactured by NOF Corporation, trade name “Blemmer PDE-50”) (hereinafter sometimes referred to as “PDE”)
(6) Silane compound (E)
Vinyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM-1003”) (hereinafter sometimes referred to as “BM”)
(7) Plasticizer (F)
・ (F-1) Adipic acid ester (manufactured by Daihachi Chemical Co., Ltd., trade name “DAIFATTY-101”)
・ (F-2) Medium-chain fatty acid triglyceride (Riken Vitamin Co., Ltd., trade name “Actor M-1”)
(8) Reactive compound (G)
(G-1) Carbodiimide compound (Matsumoto Yushi Co., Ltd., trade name “EN-160”)
(G-2) Carbodiimide compound (Nisshinbo Co., Ltd., trade name “LA-1”)
(Preparation of cross-linked polylactic acid [polylactic acid resin (A)])
Using a twin screw extruder (trade name “TEM37BS type” manufactured by Toshiba Machine Co., Ltd.), as shown in Table 1, the polylactic acid resin is supplied at a base supply port with different types and ratios, and kneaded. From the middle, a solution in which PBD, BM, PDE, and DAIFACTY-101 are mixed at the rate shown in Table 1 is injected, and melted while venting is effective under conditions of barrel temperature 190 ° C., screw rotation speed 180 rpm, and discharge rate 15 kg / h. Extrusion was performed. The molten resin discharged from the tip of the extruder is taken up in a strand shape, passed through a vat filled with cooling water, cooled, and then cut into a pellet shape to obtain a polylactic acid resin (A) (M) which is a crosslinked polylactic acid resin. -1) to (M-16) pellets were obtained.

（実施例１）
二軸押出機（東芝機械社製 商品名「ＴＥＭ３７ＢＳ型」）を用い、ポリ乳酸樹脂（Ａ）として３００１Ｄを用い、５−スルホイソフタル酸ジメチル金属塩（Ｂ）として（Ｂ−１）を用い、３００１Ｄ９９．９質量部、（Ｂ−１）０．１質量部をドライブレンドして、押出機の根元供給口から供給し、バレル温度１９０℃、スクリュー回転数２００ｒｐｍ、吐出量１５ｋｇ／ｈの条件で、ベントを効かせながら溶融押出を実施した。押出機先端から吐出された溶融樹脂をストランド状に引き取り、冷却水を満たしたバットを通過させて冷却した後、ペレット状にカッティングして、樹脂組成物のペレットを得た。得られたペレットを、７０℃にて２４時間真空乾燥した。

Example 1
Using a twin screw extruder (trade name “TEM37BS type” manufactured by Toshiba Machine Co., Ltd.), using 3001D as the polylactic acid resin (A) and using (B-1) as the 5-sulfoisophthalic acid dimethyl metal salt (B), 3001D99.9 parts by mass, 0.1 parts by mass of (B-1) are dry blended, supplied from the root supply port of the extruder, under conditions of barrel temperature 190 ° C., screw rotation speed 200 rpm, discharge rate 15 kg / h Then, melt extrusion was performed while venting was applied. The molten resin discharged from the extruder tip was taken up in a strand shape, passed through a vat filled with cooling water, cooled, and then cut into a pellet shape to obtain a resin composition pellet. The obtained pellets were vacuum dried at 70 ° C. for 24 hours.

  Then, using an injection molding machine (trade name “IS-80G type” manufactured by Toshiba Machine Co., Ltd.), the resin composition is melted at a molding temperature of 190 ° C., and the mold surface temperature is adjusted to 85 ° C. A test piece was prepared. The evaluation results are shown in Table 2.

(Examples 2-6, Comparative Examples 1-4)
3001D blending amount, 5-sulfoisophthalic acid dimethyl metal salt (B), the type of crystal nucleating agent other than 5-sulfoisophthalic acid dimethyl metal salt (B), and their blending amounts are changed, each content is Except having changed so that it might become the value shown in Table 2 and Table 3, it carried out similarly to Example 1, and obtained the pellet of the resin composition. The resin composition pellets were injection molded in the same manner as in Example 1 to prepare test pieces. The evaluation results of the examples are shown in Table 2, and the evaluation results of the comparative examples are shown in Table 3.

(Examples 7 to 29, Comparative Example 5)
Crystal nucleating agents and plasticizers other than (M-1) to (M-16), 5-sulfoisophthalic acid dimethyl metal salt (B), 5-sulfoisophthalic acid dimethyl metal salt (B) as polylactic acid resin (A) (F), the presence / absence of reactive compound (G), the type and the blending amount thereof are changed (that is, the respective contents are changed to the values shown in Table 2, Table 3 and Table 4), and these Were dry blended and supplied from the root supply port of the extruder, and melt extrusion was carried out while venting was performed under the conditions of a barrel temperature of 190 ° C., a screw rotation speed of 200 rpm, and a discharge rate of 15 kg / h. The molten resin discharged from the extruder tip was taken up in a strand shape, passed through a vat filled with cooling water, cooled, and then cut into a pellet shape to obtain a resin composition pellet.

  The obtained pellets were vacuum dried at 70 ° C. for 24 hours, and then injection-molded in the same manner as in Example 1 to prepare test pieces. The evaluation results of the examples are shown in Tables 2 and 4, and the evaluation results of the comparative examples are shown in Table 3.

実施例１〜２９で得られた樹脂組成物は、曲げ特性、耐熱性、成形性、耐衝撃性および耐久性に優れるものであった。

The resin compositions obtained in Examples 1 to 29 were excellent in bending characteristics, heat resistance, moldability, impact resistance and durability.

Examples 7 to 29 using the crosslinked polylactic acid resin (A) were particularly excellent in moldability and heat resistance.
Examples 7 to 18 and Examples 21 to 29 using the plasticizer (F) were particularly excellent in moldability and heat resistance.

Examples 13 to 18 and Examples 25 to 29 using the reactive compound (G) were particularly excellent in durability.
Examples 25 to 29 in which the D-form content of the polylactic acid resin (A) was 1.0 mol% or less were particularly excellent in moldability and heat resistance.

  In Comparative Example 1, since the dimethyl metal salt of 5-sulfoisophthalic acid (B) was not used, the molding cycle was lengthened, and the impact resistance, moldability, and heat resistance were inferior.

In Comparative Example 2, the content of 5-sulfoisophthalic acid dimethyl metal salt (B) was excessive, and thus heat resistance was poor.
In Comparative Examples 3 and 4, since a crystal nucleating agent other than dimethyl metal 5-sulfoisophthalate (B) was used, the impact resistance was poor.

  In Comparative Example 5, the content of 5-sulfoisophthalic acid dimethyl metal salt (B) was too low, and therefore the impact resistance was poor.

Claims (8)

  A resin composition comprising a polylactic acid resin (A) and a 5-sulfoisophthalic acid dimethyl metal salt (B), wherein the content of the polylactic acid resin (A) in the resin composition is 70% by mass or more. Content of 5-sulfoisophthalic acid dimethyl metal salt (B) in the product is 0.1 to 10% by mass.   2. The resin composition according to claim 1, wherein the polylactic acid resin (A) has a D-form content of 1.0 mol% or less or 99.0 mol% or more.   The resin composition according to claim 1 or 2, wherein the polylactic acid resin (A) is crosslinked.   The polylactic acid resin (A) is at least one of a (meth) acrylic acid ester compound (D), a silane compound (E) having two or more functional groups selected from an alkoxy group, an acrylic group, a methacryl group, and a vinyl group One resin is contained, The resin composition in any one of Claims 1-3 characterized by the above-mentioned.   The plasticizer (F) is contained in the resin composition, and the content of the plasticizer (F) in the resin composition is 0.1 to 15% by mass. The resin composition in any one.   The plasticizer (F) is at least selected from an aliphatic polyvalent carboxylic acid ester derivative, an aliphatic polyhydric alcohol ester derivative, an aliphatic oxyester derivative, an aliphatic polyether derivative, and an aliphatic polyether polyvalent carboxylic acid ester derivative. It is 1 type, The resin composition of Claim 5 characterized by the above-mentioned.   The resin composition contains at least one reactive compound (G) selected from a carbodiimide compound, an epoxy compound, and an oxazoline compound, and the content of the reactive compound (G) in the resin composition is 0.1. It is 10 mass%, The resin composition in any one of Claims 1-6 characterized by the above-mentioned.   The molded object formed by shape | molding the resin composition in any one of Claims 1-7.