WO2015060029A1

WO2015060029A1 - Polylactic acid-containing thermoplastic resin composition and molded product thereof

Info

Publication number: WO2015060029A1
Application number: PCT/JP2014/073735
Authority: WO
Inventors: 川口　英一郎; 恭之広本
Original assignee: ユーエムジー・エービーエス株式会社
Priority date: 2013-10-22
Filing date: 2014-09-09
Publication date: 2015-04-30
Also published as: JP5737359B2; CN105452377A; CN105452377B; JP2015081282A

Abstract

A polylactic acid-containing thermoplastic resin composition which enables the production of a molded article that can be molded in a practically satisfactory molding cycle and has excellent mechanical properties including impact resistance, excellent heat resistance, excellent weld appearance and the like. The polylactic acid-containing thermoplastic resin composition comprises: 100 parts by weight of a polylactic acid-containing thermoplastic resin component which comprises 50 to 95 parts by weight of a polylactic acid resin (A) and 5 to 50 parts by weight of a rubber-reinforced resin (B); 0.1 to 3 parts by weight of a nucleating agent (C); 1 to 15 parts by weight of a filler (D); and 0.03 to 3 parts by weight of a dispersant (E). The rubber-reinforced resin (B) comprises 30 to 100% by weight of a rubber-containing graft copolymer (b-1) and 0 to 70% by weight of a hard (co)polymer (b-2).

Description

Polylactic acid-based thermoplastic resin composition and molded article thereof

The present invention relates to a polylactic acid-based thermoplastic resin composition capable of providing a molded article having a short molding cycle and excellent mechanical properties such as impact resistance, heat resistance, and appearance, and the polylactic acid-based thermoplastic resin composition It is related with the molded article formed by shape | molding.

上昇 Increase in the concentration of carbon dioxide in the atmosphere has been pointed out as a cause of global warming, and the need to regulate carbon dioxide emissions on a global scale has been advocated. As carbon neutral, the effective use of plant resources that absorb and fix carbon dioxide is attracting attention.

Also in plastics, plastics using biomass were developed from those based on conventional petroleum. Initially, these attracted attention as biodegradable resins, but recently their significance has been reviewed as plant-based plastics.

Practical use of polylactic acid resin (PLA) is expected as plant-based plastic. Plastics consisting only of polylactic acid resin are inferior in impact strength compared to existing petroleum plastics and have a long molding cycle.

It is known to blend a rubbery polymer in order to improve the impact strength of polylactic acid resin plastics.

Patent Document 1 (Japanese Patent Application Laid-Open No. 2002-37987) describes a method using a thermoplastic elastomer. Patent Document 2 (Japanese Patent Application Laid-Open No. 2005-226054) describes a method of blending a modified conjugated diene polymer. Patent Document 3 (Japanese Patent Laid-Open No. 2009-256403) describes a method of blending a block copolymer of styrene and a methacrylic acid ester. These have the effect of improving impact strength. However, the modification is performed in a state where the mold temperature is low and polylactic acid is in an amorphous state, and none of them is sufficiently improved in heat resistance as compared with existing general-purpose plastics.

In Patent Document 4 (Japanese Patent Laid-Open No. 2005-162867) and Patent Document 5 (Japanese Patent Laid-Open No. 2005-272679), polylactic acid is crystallized and heat resistance is improved by adding a crystal nucleating agent. Is described. However, although the crystallization is promoted by the addition of the crystal nucleating agent, the crystallization time may be prolonged, and the impact strength and the like are not improved.

Patent Document 6 (Japanese Patent Laid-Open No. 2008-246554) discloses molding by a heat and cool method in which the mold temperature is raised and lowered rapidly after molding. However, this is a special molding method, which requires a long molding time and is not a general production method.

JP 2002-37987 A JP 2005-226054 A JP 2009-256403 A JP 2005-162867 A JP 2005-272679 A JP 2008-246554 A

The present invention provides a polylactic acid-based thermoplastic resin composition that can be molded with a practically sufficient molding cycle, and that can provide a molded product having excellent mechanical properties such as impact resistance, heat resistance, and weld appearance. And it aims at providing the molded article formed by shape | molding this polylactic acid-type thermoplastic resin composition.

As a result of diligent efforts to verify and improve the prior art, the present inventors crystallized polylactic acid resin in a short time to impart heat resistance, and even when polylactic acid is crystallized, it has high impact resistance and the like. The present inventors have found a resin composition that is kept in a state and excellent in appearance of a molded product, and has reached the present invention.

The gist of the present invention is that 100 parts by weight of a polylactic acid-based thermoplastic resin component containing 50 to 95 parts by weight of a polylactic acid resin (A) and 5 to 50 parts by weight of a rubber-reinforced resin (B) (however, polylactic acid resin ( A) and rubber-reinforced resin (B) in total 100 parts by weight)) 0.1 to 3 parts by weight of nucleating agent (C), 1 to 15 parts by weight of filler (D), and dispersant (E) A polylactic acid-based thermoplastic resin composition containing 0.03 to 3 parts by weight, wherein the rubber-reinforced resin (B) is a rubber-containing graft copolymer (b-1) 30 to 100 A polylactic acid-based thermoplastic resin composition characterized by comprising 0 to 70% by weight of a rigid (co) polymer (b-2) by weight.

It is preferable to use two or more types of dispersant (E) in combination.

The filler (D) is more preferably not in the shape of needles, and the shape of the fillers in the shape of needles is preferably 7 parts by weight or less with respect to 100 parts by weight of the polylactic acid-based thermoplastic resin component.

Another gist of the present invention resides in a molded article formed by molding the polylactic acid-based thermoplastic resin composition of the present invention.

The polylactic acid-based thermoplastic resin composition of the present invention is excellent in the surface appearance of a molded product obtained by molding it. This molded article has a good balance of mechanical strength such as impact strength, rigidity, and heat resistance, and has a short molding cycle. Therefore, this composition is suitable for use as various cases and structural members.

The polylactic acid-based thermoplastic resin composition of the present invention can contribute to the reduction of environmental burden by expanding the use of polylactic acid resin, which is a plant-based resin, and promoting the practice of the philosophy of carbon neutral.

Hereinafter, embodiments of the present invention will be described in detail.

In this specification, “(co) polymerization” means both “polymerization” and “copolymerization”. “(Meth) acryl” means both “acryl” and “methacryl”.

Weight average molecular weight (Mw) of polylactic acid resin (A), weight average molecular weight (Mw) of hard (co) polymer (b-2), and acetone-soluble content of rubber-containing graft copolymer (b-1) The weight average molecular weight (Mw) of each is measured by dissolving in tetrahydrofuran (THF) with gel permeation chromatography (GPC) and converted to polystyrene (PS).

[Polylactic acid thermoplastic resin component]
The polylactic acid-based thermoplastic resin component is composed of a polylactic acid resin (A) and a rubber-reinforced resin (B). The rubber-reinforced resin (B) may be composed only of the rubber-containing graft copolymer (b-1). The rubber-containing graft copolymer (b-1) and the hard (co) polymer (b- 2).

{Polylactic acid resin (A)}
The polylactic acid resin (A) can be obtained by known means such as a method of directly dehydrating condensation polymerization of lactic acid or a method of ring-opening polymerization of lactide.

There are three types of optical isomers in polylactic acid resin: L-form, D-form, and DL-form. Some of the commercially available polylactic acid resins have a purity of L form close to 100%. However, the polylactic acid resin (A) used in the present invention has an optical purity of L form or D form from the viewpoint of crystallization. Is preferably 98% or more. The polylactic acid resin (A) may be a copolymer containing other copolymer components.

Other copolymer components contained in the polylactic acid resin (A) include ethylene glycol, propylene glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanedimethano Glycol compounds such as benzene, neopentyl glycol, glycerin, pentaerythritol, bisphenol A, polyethylene glycol, polypropylene glycol, polytetramethylene glycol; oxalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid , Malonic acid, glutaric acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4 Dicarboxylic acids such as 4'-diphenyl ether dicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium isophthalic acid; hydroxy such as glycolic acid, hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxybenzoic acid Carboxylic acid; lactones such as caprolactone, valerolactone, propiolactone, undecalactone, 1,5-oxepan-2-one and the like. The content of the copolymer component is usually preferably 30 mol% or less, more preferably 10 mol% or less, based on all monomer components in the polylactic acid resin (A).

The molecular weight and molecular weight distribution of the polylactic acid resin (A) are not particularly limited as long as it can be practically processed. The weight average molecular weight of the polylactic acid resin (A) is usually 10,000 or more, preferably 50,000 or more, and more preferably 100,000 or more. The upper limit of the weight average molecular weight of the polylactic acid resin (A) is not particularly limited, but is usually 400,000 or less.

The molecular weight of the polylactic acid resin (A) can be measured by GPC (solvent THF) as described above. When the polylactic acid resin (A) is in the form of pellets, it may be difficult to dissolve in THF. In that case, after dissolving in chloroform, the polymer component is precipitated using methanol and the polymer component is dried. Can be dissolved in THF and the molecular weight of the soluble component can be measured. It can also be dissolved by heating, if necessary.

The blending amount of the polylactic acid resin (A) in the polylactic acid-based thermoplastic resin component is such that the polylactic acid resin (A) and rubber-reinforced resin (B ) And 50 to 95 parts by weight, preferably 60 to 95 parts by weight, more preferably 70 to 85 parts by weight. If the blending amount of the polylactic acid resin (A) is less than this range, the object of the present invention for effectively using the polylactic acid resin cannot be achieved, and if more, the polylactic acid-based thermoplastic resin having excellent impact resistance. A molded product cannot be obtained.

Polylactic acid resin (A) may be used alone or in combination of two or more.

Specific examples of the polylactic acid resin (A) include “NATUREWORKS” manufactured by Nature Works and “Levoda” manufactured by China Marine Biomaterials Company.

{Rubber reinforced resin (B)}
The rubber-reinforced resin (B) is composed of 30 to 100% by weight of a rubber-containing graft copolymer (b-1) obtained by graft polymerization of a hard (co) polymer to a rubbery polymer, and a hard (co) polymer (b-2). ) 0 to 70% by weight (total of 100% by weight of (b-1) and (b-2)).

<Rubber-containing graft copolymer (b-1)>
The rubber-containing graft copolymer (b-1) is a rubber-based polymer such as vinyl cyanide monomer, aromatic vinyl monomer, (meth) acrylic acid ester monomer, etc. It is obtained by graft polymerization of at least one kind of body, and generally has a structure in which a hard (co) polymer is graft-polymerized on a rubbery polymer expressed by ABS, ASA, AES, MBS or the like.

The rubbery polymer forming the rubber-containing graft copolymer (b-1) is preferably a butadiene rubber such as polybutadiene, styrene / butadiene copolymer, acrylate ester / butadiene copolymer, or styrene / isoprene. Conjugated diene rubbers such as copolymers; Acrylic rubbers such as polybutyl acrylate; Olefin rubbers such as ethylene / propylene copolymers; Silicone rubbers such as polyorganosiloxane; Polybutadiene is particularly preferable from the viewpoint. These rubbery polymers can be used singly or in combination of two or more.

This rubbery polymer can be polymerized from a monomer. The rubbery polymer may have a core / shell structure, for example, a structure in which polybutadiene is used as a core and acrylic acid ester is used as a shell.

The gel content of the rubbery polymer is preferably 50 to 99% by weight, more preferably 60 to 95% by weight, and particularly preferably 70 to 85% by weight. When the gel content is within this range, the properties of the resulting polylactic acid-based thermoplastic resin composition, particularly the impact strength, can be improved.

In order to measure the gel content of the rubbery polymer, the weighed rubbery polymer was dissolved in a suitable solvent at room temperature (23 ° C.) over 20 hours, and then fractionated with a 100 mesh wire mesh, The insoluble matter remaining on the wire mesh is dried at 60 ° C. for 24 hours and then weighed. The ratio (% by weight) of the insoluble matter with respect to the rubber polymer before fractionation is determined and used as the gel content of the rubber polymer. The solvent used for dissolving the rubber polymer is preferably toluene for polybutadiene and acetone for polybutyl acrylate.

The particle size of the rubbery polymer is preferably 0.1 to 1 μm, more preferably 0.2 to 0.5 μm, but is not limited thereto. The average particle diameter of the rubbery polymer can be measured by an optical method before graft polymerization. After the graft polymerization, the average particle diameter can be calculated using a transmission electron microscope (TEM) after dyeing the rubber polymer with a dyeing agent.

The rubber-containing graft copolymer (b-1) is preferably obtained by graft polymerization of 60 to 20% by weight of the graft-polymerizable monomer component in the presence of 40 to 80% by weight of the above rubbery polymer. (However, the total of the rubbery polymer and the monomer mixture is 100% by weight). When the rubber polymer is at least the above lower limit, the resulting polylactic acid-based thermoplastic resin molded article has good impact resistance. When the rubbery polymer is not more than the above upper limit value, it is possible to prevent the impact resistance and fluidity from being lowered.

The monomer component that can be graft-polymerized to the rubbery polymer is preferably a vinyl cyanide monomer, an aromatic vinyl monomer, a methacrylic acid ester monomer, an acrylic acid ester monomer, One or more maleimide compounds.

The vinyl cyanide monomer is preferably acrylonitrile, methacrylonitrile or the like, and acrylonitrile is particularly preferable.

The aromatic vinyl monomer is preferably styrene, α-methylstyrene, p-methylstyrene, bromostyrene, etc., and particularly preferably styrene or α-methylstyrene.

The methacrylic acid ester monomer is preferably methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and derivatives thereof, and methyl methacrylate is particularly preferable.

The acrylic acid ester monomer is preferably methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and derivatives thereof, and methyl acrylate is particularly preferable.

The maleimide compound is preferably N-phenylmaleimide, N-cyclohexylmaleimide or the like.

These monomer components may include a monomer modified with a functional group. Examples of such a monomer include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, and fumaric acid. These may be used alone or in combination of two or more. The proportion of the monomer modified with a functional group is preferably 30% by weight or less, particularly preferably 10% by weight or less, based on 100% by weight of the total monomer components.

The monomer component to be grafted to the rubbery polymer of the rubber-containing graft copolymer (b-1) is, in particular, a combination of a vinyl cyanide monomer and an aromatic vinyl monomer among the above monomers. A combination of a methacrylic acid ester monomer and an acrylic acid ester monomer is preferable.

From the viewpoint of further improving the impact resistance of the resulting polylactic acid-based thermoplastic resin molded article, in the combination of vinyl cyanide monomer and aromatic vinyl monomer, the vinyl cyanide monomer is preferably It is acrylonitrile and the aromatic vinyl monomer is preferably styrene. The weight composition ratio of the vinyl cyanide monomer and the aromatic vinyl monomer is preferably in the range of 20/80 to 35/65, more preferably 25/75 to 30/70. By being in this range, dispersibility and thermal stability are improved.

From the point that the impact resistance of the resulting polylactic acid-based thermoplastic resin molded article can be further improved, the weld appearance can be improved, and the cooling time can be shortened. In this combination, the methacrylic ester monomer is preferably methyl methacrylate, and the acrylate monomer is preferably methyl acrylate. The weight composition ratio of the methacrylic ester monomer to the acrylate ester monomer is preferably 100/0 to 50/50, more preferably in the range of 99/1 to 80/20. By being in this range, the cooling time can be shortened while maintaining the weld appearance, and the moldability becomes good.

When the rubber-reinforced resin (B) comprises only the rubber-containing graft copolymer (b-1) and the rubber-containing graft copolymer (b-1) contains a (meth) acrylic resin component, the rubber-containing graft The monomer component grafted to the rubbery polymer of the copolymer (b-1) preferably contains a (meth) acrylate monomer.

The weight average molecular weight of the acetone-soluble component of the rubber-containing graft copolymer (b-1) is preferably 50,000 to 600,000, more preferably 50,000 to 550,000, still more preferably 100,000 to 450,000. When the weight-average molecular weight of the acetone-soluble component of the rubber-containing graft copolymer (b-1) is at least the above lower limit, the resulting polylactic acid-based thermoplastic resin molded article has sufficient impact resistance. . When the weight average molecular weight of the acetone-soluble component of the rubber-containing graft copolymer (b-1) is not more than the above upper limit, the processability of the polylactic acid-based thermoplastic resin composition becomes good. The acetone-soluble component corresponds to a polymer product of a monomer that is not graft-polymerized to the rubbery polymer that is generated when the monomer is graft-polymerized to the rubbery polymer.

The graft ratio of the rubber-containing graft copolymer (b-1) ((acetone insoluble matter weight / rubber polymer weight-1) × 100) is preferably 15 to 120% by weight, and preferably 20 to 85% by weight. It is more preferable that When the graft ratio of the rubber-containing graft copolymer (b-1) is at least the above lower limit, the dispersibility and impact strength of the rubber-like polymer are improved. When the graft ratio of the rubber-containing graft copolymer (b-1) is not more than the above upper limit value, the impact resistance strength and moldability are improved. The grafted copolymer may have a structure occluded not only inside but also inside the rubbery polymer.

Graft polymerization can be performed by emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization, and may be a method combining these polymerization methods.

As the rubber-containing graft copolymer (b-1), two or more kinds of rubber-containing graft copolymers having different polymerization methods and component compositions may be mixed and used.

<Hard (co) polymer (b-2)>
The monomer component used in the hard (co) polymer (b-2) is preferably one or more of the monomers introduced in the rubber-containing graft copolymer (b-1). is there. For example, aromatic vinyl monomers, vinyl cyanide monomers and (meth) acrylic acid ester monomers, and other monomers copolymerizable with these monomers used as necessary The body can be used. The ratio of the monomer component forming the hard (co) polymer (b-2), other monomers that can be copolymerized, etc. are described in the rubber-containing graft copolymer (b-1). Can be used within the range described in.

The weight average molecular weight (Mw) of the hard (co) polymer (b-2) is preferably 30,000 to 300,000, more preferably 50,000 to 250,000. When the weight average molecular weight of the hard copolymer (b-2) is at least the above lower limit, the resulting molded article has good impact resistance, and when it is below the above upper limit, the moldability is good. Become.

The rubber-reinforced resin (B) may be only the rubber-containing graft copolymer (b-1), and contains the rubber-containing graft copolymer (b-1) and the hard (co) polymer (b-2). It may be. By blending the hard (co) polymer (b-2), characteristics such as heat resistance and fluidity can be improved. The amount of the hard (co) polymer (b-2) is the sum of the rubber-containing graft copolymer (b-1) and the hard (co) polymer (b-2), which are the rubber-reinforced resin (B). When it exceeds 70% by weight with respect to 100% by weight, the rubber content in the rubber-reinforced resin (B) is reduced, so that the impact strength is lowered. Therefore, the blending amount of the hard (co) polymer (b-2) is such that the rubber-containing graft copolymer (b-1) and the hard (co) polymer (b-2) of the rubber-reinforced resin (B) 0 to 70% by weight, preferably 0 to 50% by weight, and more preferably 0 to 30% by weight in a total of 100% by weight.

When the hard (co) polymer (b-2) is blended, the weight average molecular weight of the acetone-soluble component of the rubber-containing graft copolymer (b-1) and the hard (co) polymer (b-2) Is 50,000 to 600,000, particularly 50,000 to 550,000, especially 100,000 to 450,000 as shown in the explanation of the rubber-containing graft copolymer (b-1). Is preferred. When the weight average molecular weight of the acetone-soluble component is not less than the above lower limit, the resulting polylactic acid-based thermoplastic resin molded article has good impact resistance, and if it is not more than the above-described upper limit, the polylactic acid-based thermoplastic resin composition Good formability of the product.

As the hard (co) polymer (b-2), one kind may be used alone, or two or more kinds having different compositions and molecular weights may be mixed and used.

<Rubber content>
The rubber content in the rubber-reinforced resin (B), that is, the rubber-containing graft copolymer (b-1) or the rubber-containing graft copolymer (b-1) and the hard (co) polymer (b-2) The content of the rubbery polymer in the mixture is preferably 5 to 80% by weight, particularly preferably 10 to 70% by weight. When the content of the rubbery polymer in the rubber reinforced resin (B) is not less than the above lower limit value, sufficient impact resistance can be obtained. If the rubber-reinforced polymer (B) has an excessive amount of the rubbery polymer, the impact strength may be lowered. The content of the rubbery polymer in the rubber reinforced resin (B) can be measured by using an infrared spectrometer.

<(Meth) acrylic resin component>
As a monomer component used in the rubber-containing graft copolymer (b-1) and / or the hard (co) polymer (b-2) of the rubber-reinforced resin (B), a (meth) acrylic resin component is included. You may go out. By including the (meth) acrylic resin component in the rubber reinforced resin (B), effects such as improvement in impact resistance and reduction in cooling time are further improved.

(Meth) acrylic resin component refers to (meth) acrylonitrile, among the above-mentioned monomer components exemplified as the monomer component grafted to the rubbery polymer of the rubber-containing graft copolymer (b-1). And (meth) acrylic acid ester monomers. The (meth) acrylic resin component is preferably a (meth) acrylic acid ester monomer.

The content of the (meth) acrylic resin component in the rubber-reinforced resin (B) is preferably 5 to 70% by weight, more preferably 10 to 50% by weight, and particularly preferably 15 to 40% by weight. When the (meth) acrylic resin component content in the rubber reinforced resin (B) is not less than the above lower limit, the impact resistance, moldability, and cooling time shortening effect by blending the rubber reinforced resin (B) is improved. Can be fully exhibited. When the content of the (meth) acrylic resin component in the rubber reinforced resin (B) is not more than the above upper limit value, it is possible to prevent a decrease in impact resistance and moldability.

The (meth) acrylic resin component contains at least a methacrylic acid ester as a monomer component constituting the (meth) acrylic resin component. Preferably, a polymerization component of a methacrylic acid ester monomer such as methyl methacrylate, or a methacrylic acid ester monomer and an acrylic acid ester monomer such as methyl acrylate and / or other copolymerizable monomers. It is a copolymerization component with a monomer. In the case of a (meth) acrylic resin component containing methacrylic acid ester or methacrylic acid ester and acrylic acid ester as a (co) polymerization component, the weight ratio of each monomer of methacrylic acid ester and acrylic acid ester is preferably 100 / 0 to 50/50, more preferably 99/1 to 80/20. When the methacrylic acid ester is not less than the above lower limit, the resulting polylactic acid-based thermoplastic resin composition has good thermal stability and heat resistance.

Specific examples of the copolymer of methyl methacrylate and methyl acrylate include commercially available “Parapet G” manufactured by Kuraray Co., Ltd., “Acrypet VH”, “Acrypet MD” manufactured by Mitsubishi Rayon Co., Ltd., etc. It is. By incorporating these into the polylactic acid-based thermoplastic resin composition of the present invention as a hard (co) polymer (b-2), the rubber-reinforced resin (B) contains a (meth) acrylic resin component. Can do.

[Nucleating agent (C)]
The blending amount of the nucleating agent (C) in the polylactic acid-based thermoplastic resin composition is 100 parts by weight in total of the polylactic acid resin (A) and the rubber-reinforced resin (B) in terms of improving impact resistance and heat resistance. The amount is 0.1 to 3 parts by weight, preferably 0.5 to 2.5 parts by weight, more preferably 0.5 to 2 parts by weight. If the blending amount of the nucleating agent (C) is less than this range, the polylactic acid resin cannot be rapidly crystallized. If the blending amount of the nucleating agent (C) is larger than this range, a polylactic acid-based thermoplastic resin molded article having excellent impact resistance cannot be obtained.

The nucleating agent (C) is preferably a metal salt of a sulfonated compound such as an organic carboxylic acid metal salt such as sodium benzoate, a phenylphosphonic acid metal salt, a rosin acid metal salt, a phosphoric acid ester metal salt, or a phenylsulfonic acid metal salt. , Organic nucleating agents such as carboxylic acid amides, but not limited thereto.
A nucleating agent (C) may be used individually by 1 type, and 2 or more types may be mixed and used for it.

[Filler (D)]
The blending amount of the filler (D) in the polylactic acid-based thermoplastic resin composition is 100 in total from the polylactic acid resin (A) and the rubber-reinforced resin (B) in terms of impact resistance, heat resistance improvement and moldability. The amount is 1 to 15 parts by weight, preferably 3 to 15 parts by weight, and more preferably 5 to 10 parts by weight with respect to parts by weight. If the blending amount of the filler (D) is less than this range, the cooling time during molding may be longer. If the blending amount of the filler (D) is larger than this range, a polylactic acid-based thermoplastic resin molded article excellent in impact resistance and appearance cannot be obtained. Particularly preferred filler (D) is granular.

When the needle-like or plate-like filler (D) is contained, the content thereof is preferably 7 parts by weight or less with respect to 100 parts by weight of the total of the polylactic acid resin (A) and the rubber-reinforced resin (B). . When the blending amount of the needle-like filler (D) is large, the strength at the weld may be lowered or the appearance may be deteriorated. Therefore, the needle-like filler (D) is preferably a polylactic acid resin (A). And 7 parts by weight or less based on 100 parts by weight in total of the rubber-reinforced resin (B).
“Needle” refers to a so-called long shape including “fiber” and “bar”.

The filler (D) is preferably one or more of inorganic fillers such as carbon fiber, glass fiber, talc, wollastonite, calcium carbonate, and silica. Organic fillers such as plant-derived fibers such as kenaf and bamboo fibers may be used. One or more inorganic fillers and one or more organic fillers may be mixed and used.

If the size of the filler (D) is excessively large, the moldability, fluidity and appearance may be impaired. If excessively small, the impact resistance, heat resistance and molding cycle of the filler (D) are reduced. There is a possibility that the improvement effect cannot be obtained. The size of the filler (D) is preferably in the following range depending on its shape.

Granular filler: The average particle diameter is 0.8 to 1.8 μm. The average particle diameter is a value of the median diameter of D50.
Needle-like filler: fiber length of 30 to 200 μm, fiber diameter of 3 to 10 μm. The fiber length is a value of the length of the long side portion observed by SEM, and the fiber diameter is an average value of the long diameter of the cross section.
Plate-like filler: average particle diameter of 3 to 10 μm, aspect ratio of 0.5 to 4. The average particle diameter and the median diameter of D50.

[Dispersant (E)]
The blending amount of the dispersant (E) in the polylactic acid-based thermoplastic resin composition is such that the polylactic acid resin (A) and the rubber-reinforced resin (B) are in terms of impact resistance, heat resistance improvement, moldability, and appearance. The total amount is 0.03 to 3 parts by weight, preferably 0.1 to 3 parts by weight, more preferably 0.1 to 2 parts by weight. If the blending amount of the dispersant (E) is less than this range, the cooling time during molding may become longer. When the blending amount of the dispersant (E) is larger than this range, a polylactic acid-based thermoplastic resin molded article having excellent heat resistance cannot be obtained.

The dispersant (E) that can be used is preferably glycerin fatty acid ester, polyglycerin fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, ethylene glycol fatty acid ester, polyethylene glycol dibenzoate, caprylic acid monoglyceride diacetate, Esters such as montanic acid ester, amide compounds such as ethylene bis fatty acid amide, ethylene bis stearic acid amide, higher fatty acid polyamide, zinc stearate, magnesium stearate, lithium stearate, calcium stearate, zinc phosphate, magnesium phosphate, Examples thereof include, but are not limited to, metal salts such as lithium phosphate and calcium phosphate, and plant-derived oils such as hydrogenated castor oil. The dispersant (E) is particularly preferably glycerin fatty acid ester or calcium phosphate.

As the dispersant (E), one type may be used alone, or two or more types may be mixed and used. From the viewpoint of shortening the cooling time, two or more dispersants (E) are preferably used. More preferably, the dispersant (E) is at least one metal salt and at least one other dispersant. Since the cooling time is shortened and the weld appearance is excellent, the dispersant (E) is a combination of glycerin fatty acid ester and calcium phosphate.

When one or more metal salts and one or more other dispersants are used in combination, the proportion of the metal salt in the total amount of the dispersant (E) is 5 to 50% by weight, particularly from the viewpoint of hydrolysis resistance. 7 to 35% by weight.

[Other ingredients]
The polylactic acid-based thermoplastic resin composition includes the above-mentioned polylactic acid resin (A), rubber-reinforced resin (B), that is, a rubber-containing graft copolymer (b-1) and a hard (co) compounded as necessary. In addition to the polymer (b-2), the nucleating agent (C), the filler (D), and the dispersing agent (E), various additives and other resins may be contained. Various additives include antioxidants, UV absorbers, lubricants, plasticizers, stabilizers, mold release agents, antistatic agents, colorants (pigments, dyes, etc.), flame retardants (halogen flame retardants, phosphorus flame retardants) 1 type or 2 or more types, such as a flame retardant, an antimony compound, etc.), an anti-drip agent, an antibacterial agent, an antifungal agent, a silicone oil, a coupling agent, an anti-hydrolysis agent.

Other resins include rubber-reinforced styrene resins such as HIPS resin, ASA resin, AES resin, AS resin, polystyrene resin, polycarbonate resin, nylon resin, methacrylic resin, polyvinyl chloride resin, polybutylene terephthalate resin, polyethylene terephthalate resin , Polyphenylene ether resin, polyethylene resin, polyethylene naphthalate resin, polypropylene resin, polypropylene terephthalate resin, polyphenylene sulfide resin, polyacetal resin, polyimide resin, phenol resin, melamine resin, silicone resin, unsaturated polyester resin, epoxy resin, etc. . A blend of two or more of these may be used. The resin modified with a compatibilizer or a functional group may be used.

The content of the above-mentioned other resins in the polylactic acid-based thermoplastic resin composition of the present invention is preferably from 100 parts by weight of the polylactic acid-based thermoplastic resin component in terms of effective use of the polylactic acid resin (A). 50 parts by weight or less, particularly preferably 30 parts by weight or less.

[Production and molding of polylactic acid-based thermoplastic resin composition]
For pelletizing the polylactic acid-based thermoplastic resin composition of the present invention, a twin screw extruder, a Banbury mixer, a heating roll, or the like can be used, but is not limited thereto. Of these, melt kneading with a twin screw extruder is preferred. Resins and other additives can be blended by side feed or the like.

The polylactic acid-based thermoplastic resin composition of the present invention is molded into various molded products by a normal molding method such as injection molding, blow molding, sheet molding, or vacuum molding. The molding method of the polylactic acid-based thermoplastic resin composition is particularly preferably an injection molding method.

The molded product of the polylactic acid-based thermoplastic resin composition of the present invention includes housing components for white goods such as refrigerators and washing machines, housings for mobile phones, home appliances such as charging stands, floor boards in the trunk, tire covers, floors Although it can use suitably for motor vehicles relations, such as a box, it is not limited to these.

When preparing each component of the polylactic acid-based thermoplastic resin composition of the present invention, or when mixing, kneading, or molding these components, the resin waste, etc., is crushed as it is or in some cases. It can be subjected to a melt regeneration process. In this case, it can be recovered during molding, but it can also be recovered separately and used as a raw material in the above-described pellet manufacturing process.

Hereinafter, the present invention will be described more specifically with reference to synthesis examples, examples, and comparative examples. The present invention is not limited to the following examples unless it exceeds the gist.
Hereinafter, “part” means “part by weight”.

The weight average molecular weight was measured by a standard PS (polystyrene) conversion method using Tosoh Co., Ltd. product: GPC (gel permeation chromatography, solvent; THF).
The average particle diameter of the rubber polymer was determined by a dynamic light scattering method using Nikkiso Co., Ltd .: Microtrac Model: 9230UPA.
The weight composition ratio of the monomer was determined using FT-IR manufactured by Horiba, Ltd.

[Polylactic acid resin (A)]
Polylactic acid resin (a-1): Polylactic acid resin (L-form / D-form = 98/2 (weight ratio), weight average molecular weight = 140,000, melting point = 171 ° C.)

[Rubber reinforced resin (B)]
{Rubber-containing graft copolymer (b-1)}
<Synthesis Example 1: Production of rubber-containing graft copolymer (b-1-1)>
A rubber-containing graft copolymer was synthesized by the emulsion polymerization method with the following composition.

[Combination]
Styrene (ST): 25 parts Acrylonitrile (AN): 10 parts Polybutadiene latex: 65 parts (as solids)
Disproportionated potassium rosinate: 1 part Potassium hydroxide: 0.03 part Tertiary decyl mercaptan (t-DM): 0.04 part Cumene hydroperoxide: 0.3 part Ferrous sulfate: 0.007 part Pyrroline Sodium acid: 0.1 part Crystal glucose: 0.3 part Distilled water: 190 parts

An autoclave is charged with distilled water, disproportionated potassium rosinate, potassium hydroxide and polybutadiene latex (gel content 80% by weight, average particle size 0.3 μm), heated to 60 ° C., ferrous sulfate, sodium pyrophosphate Crystalline glucose was added. While maintaining at 60 ° C., ST, AN, t-DM and cumene hydroperoxide were continuously added over 2 hours. Thereafter, the temperature was raised to 70 ° C. and maintained for 1 hour to complete the reaction. An antioxidant was added to the ABS latex obtained by such a reaction, then coagulated with sulfuric acid, sufficiently washed with water, and dried to obtain an ABS graft copolymer (b-1-1).

<Synthesis Example 2: Production of rubber-containing graft copolymer (b-1-2)>
In the raw material blend of Synthesis Example 1, 50 parts (as a solid content) of polybutadiene (average particle size 0.3 μm) having a gel content of 97% by weight as a rubbery polymer and 37 parts of styrene (ST) as a monomer Graft polymerization was carried out in the same manner as in Synthesis Example 1 except that acrylonitrile (AN) and 13 parts of acrylonitrile (AN) were reacted to obtain an ABS graft copolymer (b-1-2).

<Synthesis Example 3: Production of rubber-containing graft copolymer (b-1-3)>
In the raw material formulation of Synthesis Example 1, 60 parts (as solid content) of polybutyl acrylate (gel content 65% by weight, average particle size 0.34 μm) was used as the rubbery polymer, and methyl methacrylate ( Graft copolymerization was carried out in the same manner as in Synthesis Example 1 except that 36 parts of MMA and 4 parts of methyl acrylate (MA) were reacted to obtain a graft copolymer (b-1-3).

The measurement results of the rubber content, the weight composition ratio of the monomer, the graft ratio, and the weight average molecular weight of the acetone-soluble component of the rubber-containing graft copolymer produced in Synthesis Examples 1, 2, and 3 are as follows. there were.
Rubber-containing graft copolymer (b-1-1):
Rubber content = 66.2 wt%
AN / ST = 28/72
Graft ratio = 40% by weight
Weight average molecular weight (Mw) = 154,000
Rubber-containing graft copolymer (b-1-2):
Rubber content = 52.4% by weight
AN / ST = 26/74
Graft ratio = 57% by weight
Weight average molecular weight (Mw) = 145,000
Rubber-containing graft copolymer (b-1-3):
Rubber content = 62.3 wt%
MMA / MA = 90/10
Graft ratio = 35% by weight
Weight average molecular weight (Mw) = 70,000

{Hard (co) polymer (b-2)}
<Synthesis Example 4: Production of Rigid Copolymer (b-2-1)>
A hard copolymer was synthesized by a suspension polymerization method as follows.
120 parts water, 0.002 parts sodium alkylbenzenesulfonate, 0.5 parts polyvinyl alcohol, 0.3 parts azoisobutylnitrile, 0.5 parts t-DM, 25 parts acrylonitrile (AN), styrene A monomer mixture consisting of 25 parts (ST) and 50 parts methyl methacrylate (MMA) was charged. The mixture was heated while sequentially adding a part of styrene, and the temperature was raised from 60 ° C. to 120 ° C. in 5 hours. Furthermore, after reacting at 120 ° C. for 4 hours, the polymer was taken out to obtain a hard copolymer (b-2-1).

<Synthesis Example 5: Production of hard (co) polymer (b-2-2)>
Using a monomer mixture consisting of 25 parts of acrylonitrile (AN) and 75 parts of styrene (ST), polymerization was carried out in the same manner as in Synthesis Example 4 except that a part of styrene was sequentially added to obtain a hard copolymer. (B-2-2) was obtained.

The measurement results of the weight composition ratio and weight average molecular weight (Mw) of the monomers of the hard copolymer produced in Synthesis Examples 4 and 5 were as follows.
Rigid copolymer (b-2-1):
AN / ST / MMA = 23/28/49
Weight average molecular weight (Mw) = 113,000
Rigid copolymer (b-2-2):
AN / ST = 25/75
Weight average molecular weight (Mw) = 150,000

[Other additives]
The following were used for the nucleating agent (C), filler (D), and dispersing agent (E).

{Nuclear agent (C)}
Nucleating agent (c-1): “Eco Promote PPA-ZN” (Zinc Phenylsulfonate (II)) manufactured by Nissan Chemical Co., Ltd.

{Filler (D)}
Filler (d-1): “TP-A25” manufactured by Fuji Talc Kogyo Co., Ltd. (talc (plate), average particle diameter 5 μm, plate aspect ratio 2.0)
Filler (d-2): “NYGLOS8” manufactured by Sakai Kogyo Co., Ltd. (wollastonite (needle shape), fiber length 136 μm, fiber diameter 8 μm)
Filler (d-3): “NS-1000” manufactured by Nitto Flour Chemical Co., Ltd. (calcium carbonate (granular), average particle size 1.2 μm)

{Dispersant (E)}
Dispersant (e-1): “VR-02” (glycerin fatty acid ester surfactant) manufactured by Taiyo Kagaku Co., Ltd.
Dispersant (e-2): “Rikaflow LA-100” (polyethylene glycol dibenzoate) manufactured by Shin Nippon Rika Co., Ltd.
Dispersant (e-3): “HAP-08NP” (calcium phosphate) manufactured by Maruo Calcium Co., Ltd.

[Production and evaluation of polylactic acid-based thermoplastic resin composition pellets]
The above components were mixed in the mixing ratios shown in Tables 1 and 2, and further mixed with 0.3 parts of “Carbodilite HMV-8CA” manufactured by Nisshinbo Co., Ltd. as a stabilizer, and then mixed at 200 to 240 ° C. with 2 parts. Pellets of a polylactic acid-based thermoplastic resin composition were prepared by melt mixing with a shaft extruder (“TEX-30α” manufactured by Nippon Steel Works) and pelletizing.

The obtained resin pellets were molded at 200 to 220 ° C. with a 2 ounce injection molding machine (manufactured by Toshiba Corporation). The molded article thus obtained was measured for impact resistance (Charpy impact strength), bending strength, bending elastic modulus, and heat resistance (load deflection temperature) by the following methods.
Charpy impact strength (KJ / m): ISO 179 (normal temperature)
Bending strength (MPa): ISO 178 (normal temperature)
Flexural modulus (MPa): ISO 178 (normal temperature)
Deflection temperature under load (° C): ISO 75 (measurement load 0.45 MPa)

When the obtained resin pellet was molded at 200 to 220 ° C. with a 2 ounce injection molding machine (manufactured by Toshiba Corporation), the time until the ISO tensile test piece was taken out was defined as the cooling time.
Two types of tensile test pieces were formed: a one-point gate test piece and a two-point gate test piece. The weld appearance was visually confirmed with a two-point gate test piece and evaluated according to the following criteria.
◎: Very good appearance without welds ○: Very little weld and good appearance ×: Welded, poor appearance Tensile measurement is a test piece of one-point gate and two-point gate test at ISO 527 (room temperature) The test was performed on the piece, and the tensile strength of the test piece of the two-point gate / the tensile strength of the test piece of the one-point gate × 100 = weld strength retention was calculated.

[Examples and Comparative Examples]
The results of Examples 1 to 10 and Comparative Examples 1 to 7 are shown in Tables 1 and 2.

[Discussion]
Tables 1 and 2 show the following.
The polylactic acid-based thermoplastic resin compositions of Examples 1 to 10 that satisfy the requirements of the claims of the present invention have a short molding cycle and are excellent in mechanical properties such as impact resistance, heat resistance, and weld strength. Can be obtained. In particular, a system to which two or more kinds of dispersants are added has a short molding cycle and is excellent in weld strength and weld appearance.
In contrast, the polylactic acid resin alone of Comparative Example 1 has a long cooling time and low impact strength and heat resistance. In Comparative Example 2, since the nucleating agent and the dispersing agent are not included, the cooling time is long and other physical properties are inferior, which is not practical. In Comparative Examples 3 and 4 containing no dispersant, although the cooling time is shortened, the weld strength is lowered and the weld appearance is also poor. In Comparative Example 5 containing no filler, the cooling time is long, and actual molding is not sufficient. Even in the case where the dispersant is added, the weld strength and the weld appearance are inferior in Comparative Example 6 in which the number of added parts is larger than the range of the present invention. In Comparative Example 7 in which the blending amount of the polylactic acid resin is small, the crystallinity is low due to the small amount of polylactic acid, the cooling time is long, and the weld appearance and weld strength retention are also poor.

The molded product formed by molding the polylactic acid-based thermoplastic resin composition of the present invention has a short molding cycle, good color development, good weld appearance, and excellent balance of mechanical strength such as impact resistance and heat resistance. . A molded product formed by molding the polylactic acid-based thermoplastic resin composition of the present invention is a material suitable for use as various cases and structural members. The molded product formed by molding the polylactic acid-based thermoplastic resin composition of the present invention can be used for various applications according to market needs, and has an extremely high industrial utility and environmental load. It is also effective in reducing

Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application No. 2013-219345 filed on October 22, 2013, which is incorporated by reference in its entirety.

Claims

100 parts by weight of a polylactic acid-based thermoplastic resin component,
Nucleating agent (C) 0.1-3 parts by weight,
1 to 15 parts by weight of filler (D) and 0.03 to 3 parts by weight of dispersant (E),
A polylactic acid-based thermoplastic resin composition comprising
100 parts by weight of the polylactic acid-based thermoplastic resin component comprises 50 to 95 parts by weight of the polylactic acid resin (A) and 5 to 50 parts by weight of the rubber-reinforced resin (B) (provided that the polylactic acid resin (A) and 100 parts by weight in total with the rubber reinforced resin (B)),
The rubber-reinforced resin (B) is composed of 30 to 100% by weight of a rubber-containing graft copolymer (b-1) and 0 to 70% by weight of a hard (co) polymer (b-2) (provided that the rubber contains A total of 100% by weight of the graft copolymer (b-1) and the hard (co) polymer (b-2)) a polylactic acid-based thermoplastic resin composition.
In Claim 1, the polylactic acid-type thermoplastic resin composition formed by mix | blending 2 or more types of said dispersing agents (E).
2. The polylactic acid-based thermoplastic resin composition according to claim 1, wherein the amount of acicular filler is 7 parts by weight or less in 1 to 15 parts by weight of the filler (D).
2. The rubber-containing graft copolymer (b-1) according to claim 1, wherein 60 to 20% by weight of a graft-polymerizable monomer component is graft-polymerized in the presence of 40 to 80% by weight of a rubbery polymer. A polylactic acid-based thermoplastic resin composition (however, the total of the rubbery polymer and the monomer mixture is 100% by weight).
5. The rubbery polymer according to claim 4, wherein the rubbery polymer is a polybutadiene rubber and / or an acrylic rubber, and the monomer component is a vinyl cyanide monomer and an aromatic vinyl monomer, or A polylactic acid thermoplastic resin composition which is a methacrylic acid ester monomer and an acrylic acid ester monomer.
The (meth) acrylic resin according to claim 1, wherein the rubber-reinforced resin (B) is a monomer component of the rubber-containing graft copolymer (b-1) and / or the hard (co) polymer (b-2). A polylactic acid-based thermoplastic resin composition containing 5 to 70% by weight of components.
The polylactic acid-based thermoplastic resin according to claim 2, wherein the dispersant (E) includes a metal salt and a dispersant other than the metal salt, and the proportion of the metal salt in the dispersant (E) is 5 to 50% by weight. Composition.
A molded product formed by molding the polylactic acid-based thermoplastic resin composition according to any one of claims 1 to 7.