JP2012131905A - Thermoplastic resin composition, and molding comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition excellent in flexibility, impact resistance, heat resistance and durability, and having little dependency on petroleum-based products; and to provide a molding obtained by using the same.SOLUTION: The thermoplastic resin composition comprises a polylactic acid-based resin having a weight-average molecular weight of ≥150,000 and a styrenic resin, wherein the mass ratio of polylactic acid-based resin to the styrenic resin is 90/10 to 10/90.

Description

  The present invention relates to a thermoplastic resin composition that is excellent in impact resistance, bending properties, heat resistance, and durability, and has a low dependence on petroleum-based products, and a molded body using the thermoplastic resin composition. is there.

  Generally, raw materials for molding include polypropylene resin, polystyrene resin, acrylonitrile / butadiene / styrene resin, polyamide resin such as nylon 6 and nylon 66, polyester resin such as polyethylene terephthalate and polybutylene terephthalate, and resin such as polycarbonate resin Is used.

  Since the molded body manufactured from such resin is excellent in moldability and mechanical strength, it is used for various applications. However, when it is discarded, there is a problem that the amount of garbage is increased and it is hardly decomposed in a natural environment, so that even if it is buried, it remains in the ground semipermanently. In addition, since these resins are generally made from underground petroleum resources, when incinerated, they will carry underground carbon to the surface and the atmosphere as carbon dioxide, resulting in global warming problems and resource depletion. It leads to problems and the environmental impact is high.

  On the other hand, in recent years, from the viewpoint of environmental conservation, resins using plant-derived raw materials such as polylactic acid resins have attracted attention. Among these, the polylactic acid resin is one of the resins having the highest heat resistance, and can be mass-produced. Therefore, the cost is low, and the polylactic acid resin is highly useful because it is easily decomposed in a natural environment. Polylactic acid resins can be produced using plants such as corn and sweet potato as raw materials. Since these raw material plants fix atmospheric carbon, even when polylactic acid resins are incinerated, The balance of carbon in the atmosphere is plus or minus zero, and the environmental impact is lower than that of petroleum-derived resins.

  However, even if it is a polylactic acid resin with high heat resistance among resins produced from plant-derived raw materials, it has sufficient heat resistance to withstand actual use compared to polystyrene resin, acrylonitrile / butadiene / styrene resin, etc. It may not be said that it has. In addition, polylactic acid resin has low impact strength, and compared with acrylonitrile, butadiene, styrene resin, polypropylene resin, and impact-resistant polystyrene resin, the strength when dropping the resulting product is low, so acrylonitrile butadiene・ It was difficult to use as an alternative to styrene resin or impact-resistant polystyrene resin.

  In order to improve the drawbacks of such polylactic acid-based resins, it has been proposed to mix petroleum-derived resins having excellent mechanical properties or to make alloys. Even such a mixture or alloy can save depleted resources and can reduce the balance of carbon dioxide emissions due to incineration as compared with a resin made only of petroleum resin-derived raw materials.

  For example, Patent Document 1 describes an alloy of a polylactic acid resin and a polycarbonate resin. However, in the case of Patent Document 1, a large amount of energy is required for the production of the polycarbonate resin. Therefore, compared to polylactic acid resins, polyolefin resins, polystyrene resins, acrylonitrile / butadiene / styrene resins, and impact-resistant polystyrene resins, the usage rate of petroleum energy may be higher. There was a case that I could not say.

  Patent Document 2 describes an alloy of a polylactic acid resin and impact-resistant polystyrene. Further, Patent Document 3 describes a polylactic acid resin and a resin having a glass transition temperature higher than that of the polylactic acid resin (for example, acrylonitrile / butadiene / styrene resin, acrylonitrile / styrene resin, acrylonitrile styrene acrylate, styrene elastomer). Each alloy is disclosed. However, the alloys disclosed in Patent Documents 2 and 3 may not have sufficient impact resistance, strength, and heat resistance when the content of the polylactic acid resin is large.

  Patent Document 4 discloses an alloy of a styrene-modified polylactic acid resin and a styrene resin. However, even in Patent Document 4, heat resistance may be insufficient. Furthermore, it is difficult to improve the impact resistance unless the content ratio of the polylactic acid resin is lowered, and there is a problem that the burden on the environment increases.

JP 2007-56246 A JP 2005-264086 A JP-A-2005-060637 JP 2009-079196

  The present invention is intended to solve the above-mentioned problems, and is excellent in impact resistance, bending characteristics, heat resistance and durability, and is environmentally friendly thermoplastic even if the content of polylactic acid resin is large. It aims at providing a resin composition. Furthermore, an object of this invention is to provide the molded object obtained from this thermoplastic resin composition.

  As a result of intensive studies to solve the above problems, the present inventors have found that a resin composition containing a polylactic acid resin having a specific weight average molecular weight and a polystyrene resin is excellent in impact resistance and bending properties. The present invention has been found.

That is, the gist of the present invention is as follows.
(1) A polylactic acid resin having a weight average molecular weight of 150,000 or more and a styrene resin are contained, and the mass ratio of the polylactic acid resin to the styrene resin is polylactic acid resin / styrene resin = 95 / 5-40. / 60 thermoplastic resin composition characterized by the above-mentioned.
(2) The thermoplastic resin composition according to (1), wherein the polylactic acid resin is a crosslinked polylactic acid resin.
(3) The crosslinked polylactic acid resin is 0.01 to 10 parts by mass of peroxide, 100 parts by mass of polylactic acid resin, (meth) acrylate compound and / or alkoxy group, acrylic group, methacrylic group. The thermoplastic resin composition according to (2), which is obtained by blending 0.01 to 5 parts by mass of a silane compound having two or more functional groups selected from a group and a vinyl group.
(4) The thermoplastic resin composition according to any one of (1) to (3), wherein the styrene-based resin is an acrylonitrile / styrene copolymer and / or an acrylonitrile / butadiene / styrene copolymer.
(5) Containing 0.1 to 10 parts by mass of at least one compound selected from a carbodiimide compound, an epoxy compound and an oxazoline compound with respect to 100 parts by mass of the total amount of the polylactic acid resin and the styrene resin. The thermoplastic resin composition according to any one of (1) to (4).
(6) A molded article obtained by molding the thermoplastic resin composition according to any one of (1) to (5).

  Since the thermoplastic resin composition of the present invention contains a polylactic acid resin having a weight average molecular weight of a specific value or more and a styrene resin, it has excellent impact resistance even if the content of the polylactic acid resin is large. And bending properties (bending strength, bending elastic modulus, bending breaking strain). Furthermore, it becomes what has the outstanding heat resistance by making polylactic acid-type resin into crosslinked polylactic acid-type resin. Furthermore, the thermoplastic resin composition of the present invention also has improved durability by containing at least one compound selected from a carbodiimide compound, an epoxy compound and an oxazoline compound.

  As described above, the thermoplastic resin composition of the present invention has a low dependence on petroleum products, has excellent characteristics, and can be suitably used for various applications. Then, by molding the thermoplastic resin composition of the present invention, it is possible to obtain molded bodies such as electric and electronic equipment parts and miscellaneous goods. Since the molded body obtained from the thermoplastic resin composition of the present invention uses a lot of natural-derived resins, it can contribute to the saving of depleted resources such as petroleum, and has an extremely high industrial utility value.

Hereinafter, the present invention will be described in detail.
The thermoplastic resin composition of the present invention (hereinafter sometimes simply referred to as “resin composition”) contains a polylactic acid resin having a weight average molecular weight of 150,000 or more and a styrene resin.

  The polylactic acid resin used in the present invention is mainly composed of poly (L-lactic acid), poly (D-lactic acid), or a polylactic acid resin such as a mixture or copolymer thereof. Furthermore, polyglycolic acid, polycaprolactone, polybutylene succinate, polyethylene succinate, polybutylene adipate terephthalate, polybutylene succinate terephthalate and the like may be mixed as other components. From the viewpoint of saving petroleum resources, plant-derived raw materials are good, and in particular, poly (L-lactic acid), poly (D-lactic acid), and mixtures or copolymers thereof are used in terms of heat resistance and moldability. Is desirable. From the viewpoint of biodegradability, it is preferable that poly (L-lactic acid) is the main component.

  The melting point of polylactic acid mainly composed of poly (L-lactic acid) varies depending on the ratio of the D-lactic acid component. In the present invention, however, the melting point is 160 ° C. in consideration of the mechanical properties and heat resistance of the obtained molded product. The above is preferable. In the polylactic acid mainly composed of poly (L-lactic acid), in order to make the melting point 160 ° C. or higher, the ratio of the D-lactic acid component is preferably less than 3 mol%, and less than 1 mol%. It is more preferable.

  The weight average molecular weight of the polylactic acid-based resin needs to be 150,000 or more, and is preferably 160000 or more. When the weight average molecular weight is less than 150,000, the effects of the present invention such as improvement in impact resistance and bending properties are not exhibited. In the present invention, the weight average molecular weight is a value determined in terms of standard polystyrene at 40 ° C. using a gel permeation chromatography (GPC) apparatus equipped with a differential refractive index detector and tetrahydrofuran as an eluent. If the sample is difficult to dissolve in tetrahydrofuran, prepare the sample by adding tetrahydrofuran after dissolving in a small amount of chloroform.

In addition, although the upper limit of the weight average molecular weight of polylactic acid-type resin is not specifically limited, It is preferable to set it as less than 300000 from the point of the fluidity | liquidity at the time of shaping | molding.
Simply increasing the weight average molecular weight of the polylactic acid resin does not improve the impact resistance and bending properties. This is apparent from data shown in Comparative Examples 1 and 4 described later. That is, when only a polylactic acid resin having a weight average molecular weight of 150,000 or more is used without using a styrene resin, impact resistance and bending characteristics are not improved. The present invention has been found to be a resin composition having improved impact resistance and bending properties only when a resin composition containing a polylactic acid resin having a weight average molecular weight of 150,000 or more and a styrene resin is used. It is.

  In the present invention, excellent bending characteristics means that the value of bending rupture strain is large, and the bending strength and bending elastic modulus do not necessarily have to be high, and the value of bending rupture strain is large. It is preferable to take such numerical values.

  Furthermore, the polylactic acid resin in the present invention preferably has a melt flow rate (value according to JIS K-7210 (test condition 4)) at 190 ° C. and a load of 21.2 N of 0.1 to 50 g / 10 min. 0.2 to 20 g / 10 min is more preferable, and 0.5 to 10 g / 10 min is more preferable. When the melt flow rate exceeds 50 g / 10 min, the melt viscosity is too low and the molded article 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 becomes too high, and the operability may be lowered.

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

Moreover, in this invention, in order to accelerate | stimulate crystallization of polylactic acid-type resin and to improve heat resistance, it is preferable to bridge | crosslink polylactic acid-type resin to make crosslinked polylactic acid-type resin.
As a method of crosslinking the polylactic acid resin, a peroxide and a (meth) acrylic acid ester compound and / or a functional group selected from an alkoxy group, an acrylic group, a methacryl group, and a vinyl group are added to the polylactic acid resin. A method of blending at least one silane compound (hereinafter sometimes simply referred to as “silane compound”) is preferred. That is, as a preferable method for crosslinking the polylactic acid-based resin, when using a peroxide and a (meth) acrylic acid ester compound, when using a peroxide and a silane compound, the peroxide and the (meth) acrylic acid ester compound A silane compound may be used.

  When a crosslinking agent other than a peroxide, a (meth) acrylic acid ester compound and / or a silane compound is used, the polylactic acid resin has insufficient crosslinking efficiency, so that the effect of improving heat resistance is sufficiently exhibited. It may not be possible.

  The peroxide is blended for the purpose of promoting crystallization and improving heat resistance by crosslinking the polylactic acid resin. Furthermore, by using in combination with a (meth) acrylic acid ester compound and / or a silane compound, crosslinking of the polylactic acid resin can be promoted, and the heat resistance can be further improved.

  Specific examples of peroxides include benzoyl peroxide, bis (butylperoxy) trimethylcyclohexane, bis (butylperoxy) cyclododecane, butylbis (butylperoxy) valerate, dicumyl peroxide, butylperoxybenzoate, dibutyl Examples thereof include peroxide, bis (butylperoxy) diisopropylbenzene, dimethyldi (butylperoxy) hexane, dimethyldi (butylperoxy) hexyne, and butylperoxycumene. Of these, dibutyl peroxide is preferable from the viewpoint of crosslinking efficiency.

  As for the compounding quantity of a peroxide, 0.01-10 mass parts is preferable with respect to 100 mass parts of polylactic acid-type resin, More preferably, it is 0.05-5 mass parts. Although it can be used even if it exceeds 10 parts by mass, the crosslinking effect may be saturated and may not be economical. On the other hand, if it is less than 0.01 parts by mass, the crosslinking effect may be poor. In addition, since a peroxide decomposes | disassembles and is consumed when mixing with a polylactic acid-type resin, even if it mix | blends, it may not remain | survive in the obtained resin composition.

  The (meth) acrylic acid ester compound is used in combination with a peroxide, thereby promoting the crosslinking of the polylactic acid resin and the crystallization of the resin composition and contributing to the improvement of heat resistance.

  (Meth) acrylic acid ester compounds are highly reactive with polylactic acid-based resins, hardly leave monomers, are less toxic, and have less coloring of the resin. Compounds having a 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 these, (poly) ethylene glycol dimethacrylate is preferable from the viewpoint of crystallization promoting effect and heat resistance.

  The amount of the (meth) acrylic acid ester compound is preferably 0.01 to 5 parts by mass, more preferably 0.02 to 3 parts by mass, and still more preferably 100 parts by mass of the polylactic acid resin. 0.05 to 1 part by mass. When the blending amount is less than 0.01 parts by mass, the effect of promoting crosslinking is poor. On the other hand, if the blending amount exceeds 5 parts by mass, the operability during kneading may be reduced.

The silane compound is used in combination with a peroxide to promote cross-linking of the polylactic acid resin and contribute to improvement of heat resistance.
The silane compound is represented by the following formula (I).

式（１）中、Ｒ１〜Ｒ４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、あるいはこれらの官能基を有する置換基を表す。残りは、アルコキシ基、ビニル基、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。アルコキシ基としては、例えば、メトキシ基、エトキシ基が挙げられる。ビニル基を有する置換基としては、例えばビニル基、ｐ−スチリル基が挙げられる。アクリル基を有する置換基としては、例えば３−メタクリロキシプロピル基、３−アクリロキシプロピル基などが挙げられる。アルキル基としては例えばメチル基、エチル基が挙げられる。エポキシ基を有する置換基としては、例えば３−グリシドキシプロピル基、２−（３，４―エポキシシクロヘキシル）基などが挙げられる。

In Formula (1), at least two of R1 to R4 represent a functional group selected from an alkoxy group, an acrylic group, a methacryl group, and a vinyl group, or a substituent having these functional groups. The rest represents other than an alkoxy group, a vinyl group, and an acrylic group, and examples thereof include hydrogen, an alkyl group, and an epoxy group. Examples of the alkoxy group include a methoxy group and an ethoxy group. Examples of the substituent having a vinyl group include a vinyl group and a p-styryl group. Examples of the substituent having an 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 substituent having an epoxy group include a 3-glycidoxypropyl group and a 2- (3,4-epoxycyclohexyl) group.

  Detailed examples of such silane compounds and examples of trade names include tetramethoxysilane (GE Toshiba Silicone TSL8114, Shin-Etsu Chemical KBM-04), tetraethoxysilane (GE Toshiba Silicone TSL8124, Shin-Etsu). Chemical industry KBE-04), methyltrimethoxysilane (GE Toshiba Silicone TSL8113, Shin-Etsu Chemical KBM-13), methyltriethoxysilane (GE Toshiba Silicone TSL813, Shin-Etsu Chemical KBE- 13), dimethyldimethoxysilane (GE Toshiba Silicone TSL8112), dimethyldiethoxysilane (GE Toshiba Silicone TSL8122, Shin-Etsu Chemical KBE-22), methyldimethoxysilane (GE Toshiba Silicone TSL8117), methyl Ethoxysilane (GE Toshiba Silicone TSL8127), phenyltrimethoxysilane (GE Toshiba Silicone TSL8173), phenyltriethoxysilane (GE Toshiba Silicone TSL8178, Shin-Etsu Chemical KBE-103), diphenyldimethoxysilane ( GE Toshiba Silicone TSL8172), diphenyldiethoxysilane (GE Toshiba Silicone TSL8177), hexyltrimethoxysilane (Shin-Etsu Chemical KBM-3063), decyltrimethoxysilane (Shin-Etsu Chemical KBM-3103C) 3-glycidoxypropyldimethoxymethylsilane (GE Toshiba Silicone TSL-8355), 3-glycidoxypropyltrimethoxysilane (GE Toshiba Silicone TSL-8350, Shin Chemical Industry KBM-403), dimethylvinylmethoxysilane (GE Toshiba Silicone TSL8317), methylvinyldimethoxysilane (GE Toshiba Silicone TSL8315), methylvinyldiethoxysilane (GE Toshiba Silicone TSL8316), dimethyl Vinylethoxysilane (GE Toshiba Silicone TSL8318), vinyltrimethoxysilane (Shin-Etsu Chemical KBM-1003), vinyltriethoxysilane (GE Toshiba Silicone TSL8311, Shin-Etsu Chemical KBE-1003), 2 -(3,4-epoxycyclohexyl) ethyltrimethoxysilane (KBE-303, Shin-Etsu Chemical Co., Ltd.), 3-glycidoxypropylmethyldiethoxysilane (KBE-402, Shin-Etsu Chemical Co., Ltd.), p-styryl Rimethoxysilane (KBM-1403 manufactured by Shin-Etsu Chemical Co., Ltd.), 3-methacryloxypropylmethyldimethoxysilane (TSL8375 manufactured by GE Toshiba Silicone, KBM-502 manufactured by Shin-Etsu Chemical Co., Ltd.), 3-methacryloxypropyltrimethoxysilane (GE) TSL8370 manufactured by Toshiba Silicone, KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd., 3-methacryloxypropylmethyldiethoxysilane (KBE-502 manufactured by Shin-Etsu Chemical Co., Ltd.), 3-methacryloxypropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) KBE-503), 3-acryloxypropyltrimethoxysilane (KBM-5103 manufactured by Shin-Etsu Chemical Co., Ltd.), 3-acryloxypropylmethyldimethoxysilane (KBM-5102 manufactured by Shin-Etsu Chemical Co., Ltd.), and the like.

  Among these, a silane compound 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 and trade names of such silane compounds include vinyltrimethoxysilane (KBE-1003 manufactured by Shin-Etsu Chemical Co., Ltd.), vinyltriethoxysilane (GE Toshiba Silicone Co., Ltd. TSL8311, Shin-Etsu Chemical Co., Ltd. KBE- 1003), p-styryltrimethoxysilane (KBM-1403 manufactured by Shin-Etsu Chemical Co., Ltd.), 3-methacryloxypropyltrimethoxysilane (TSL8370 manufactured by GE Toshiba Silicone Co., Ltd., KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.), 3-methacryloxy Examples thereof include propyltriethoxysilane (KBE-503 manufactured by Shin-Etsu Chemical Co., Ltd.), 3-acryloxypropyltrimethoxysilane (KBM-5103 manufactured by Shin-Etsu Chemical Co., Ltd.), and the like.

  It is preferable that the compounding quantity of a silane compound is 0.01-5 mass parts with respect to 100 mass parts of polylactic acid-type resin, More preferably, it is 0.02-3 mass parts, More preferably, it is 0.05-1. Part by mass. Although it can be used even if it exceeds 5 parts by mass, not only the crosslinking effect is saturated but also it may not be economical. On the other hand, if it is less than 0.01 parts by mass, the effect of promoting crosslinking is poor, and the effect of addition may not be recognized.

  In addition, in this invention, in order to bridge | crosslink polylactic acid-type resin, you may use combining 3 types, a peroxide, a (meth) acrylic acid ester compound, and a silane compound. In such a case, the total amount of the (meth) acrylic acid ester compound and the silane compound is preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of the polylactic acid resin. 02-3 mass parts is more preferable, and it is still more preferable that it is 0.05-1 mass part. When the total of the three types exceeds 5 parts by mass, the crosslinking effect is saturated and it may not be economical. On the other hand, when the total of the three types is less than 0.01 parts by mass, the effect of promoting crosslinking is poor, and the effect of addition may not be recognized.

  As a method for preparing a crosslinked polylactic acid-based resin, a peroxide and a (meth) acrylic acid ester compound and / or a silane compound are blended into a polylactic acid-based resin and melted using a general extruder. The method of kneading can be mentioned. In order to improve the kneading state, it is preferable to use a twin screw extruder. The kneading temperature is preferably in the range of (melting point of polylactic acid resin + 5) ° C. to (melting point of polylactic acid resin + 100) ° C., and the kneading time is preferably 20 seconds to 30 minutes. If the temperature is lower or shorter than this range, kneading or reaction becomes insufficient, and if the temperature is higher or longer, the resin may be decomposed or colored. In blending, when the (meth) acrylic acid ester compound and / or silane compound is in a solid state, a method of supplying it using a dry blend or a powder feeder is preferable. In the case of a liquid state, a pressure pump is used. A method of directly injecting into the barrel of the extruder is preferable.

  When the peroxide, (meth) acrylic acid ester compound and / or silane compound are injected into the extruder, the peroxide and (meth) acrylic acid ester compound and / or silane compound are dissolved or dispersed in the medium. Then, a method of injecting into a kneader is preferable. According to this method, operability can be remarkably improved. For example, during the melt-kneading of the polylactic acid-based resin and the peroxide, a solution or dispersion of a (meth) acrylic acid ester compound and / or a silane compound is injected, or during the melt-kneading of the polylactic acid-based resin, It can be melt-kneaded by injecting a solution or dispersion of a peroxide and a (meth) acrylic ester compound and / or a silane compound.

  Alternatively, when a (meth) acrylic acid ester and / or a silane compound is added to the polylactic acid resin, it may be added from the top feeder together with the polylactic acid resin and the styrene resin described later, or the polylactic acid resin After the (meth) acrylic acid ester and / or silane compound is added to the resin, a styrenic resin may be further added.

From the viewpoint of crosslinking efficiency, the mass ratio of the peroxide to the medium is preferably peroxide: medium = 1: 3 to 10, and more preferably 1: 5.
As a medium for dissolving or dispersing the peroxide and the (meth) acrylic acid ester compound and / or the silane compound, a general medium is used and is not particularly limited, but is excellent in compatibility with the polylactic acid resin. Plasticizers are preferred. Examples of the plasticizer include aliphatic polyvalent carboxylic acid ester derivatives, aliphatic polyhydric alcohol ester derivatives, aliphatic oxyester derivatives, aliphatic polyether derivatives, aliphatic polyether polyvalent carboxylic acid ester derivatives, and the like. .

  Plasticizers include glycerin diacetomonolaurate, glycerin diacetomonocaprate, polyglycerin acetate, polyglycerin fatty acid ester, medium chain triglyceride, dimethyl adipate, dibutyl adipate, triethylene glycol diacetate, methyl acetylricinoleate, acetyl Examples include tributyl citric acid, polyethylene glycol, dibutyl diglycol succinate, bis (butyl diglycol) adipate, bis (methyl diglycol) adipate, and the like. These may be used alone or in combination of two or more.

  Commercially available products can be suitably used as the plasticizer, and specific examples of the product names include PL-012, PL-019, PL-320, PL-710, Actor series (M- 1, M-2, M-3, M-4, M-107FR); manufactured by Taoka Chemical Co., Ltd., ATBC; manufactured by Daihachi Chemical Co., Ltd., BXA, MXA; manufactured by Taiyo Kagaku Co., Ltd., VR-01, VR-05 VR-10P, VR-10P modified 1, VR-623, and the like.

  When using a plasticizer, it is preferable that the compounding quantity is 30 mass parts or less with respect to 100 mass parts of polylactic acid-type resin, More preferably, it is 0.1-20 mass parts. When it exceeds 30 mass parts, heat resistance may fall or bleed-out may generate | occur | produce. When the reactivity of the crosslinking agent is low, it is not necessary to use a plasticizer. However, when the reactivity is high, use of 0.1 part by mass or more is preferable because it promotes crystallization of the polylactic acid resin. In addition, since this medium may volatilize at the time of mixing with resin, even if it uses it at the time of manufacture, this medium may not be contained in the obtained thermoplastic resin composition.

  The styrenic resin used in the present invention is a resin obtained by polymerizing a styrenic monomer with at least one copolymerizable vinyl monomer and / or rubbery polymer. is there. The styrene resin can be used as a resin composition having improved impact resistance and bending characteristics (particularly bending fracture strain) when used together with a polylactic acid resin having a weight average molecular weight of 150,000 or more. is there.

  Examples of the styrene monomer used for the component of the styrene resin include styrene, α-methyl styrene, o-methyl styrene, p-methyl styrene, vinyl xylene, ethyl styrene, dimethyl styrene, p-tert-butyl styrene, Examples thereof include styrene derivatives such as vinyl naphthalene, methoxystyrene, monobromostyrene, dibromostyrene, fluorostyrene, and tribromostyrene. Of these, styrene is particularly preferable from the viewpoint of heat resistance. These can be used alone or in combination of two or more.

  Other vinyl monomers copolymerizable with the styrenic monomer include vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, aryl esters of acrylic acid such as phenyl acrylate and benzyl acrylate, methyl acrylate, and ethyl acrylate. Alkyl esters of acrylic acid such as propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, cyclohexyl acrylate, dodecyl acrylate, aryl methacrylates such as phenyl methacrylate, benzyl methacrylate, methyl methacrylate, ethyl Methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate Maleic monomers such as acrylate, alkyl methacrylates such as 2-ethylhexyl methacrylate, octyl methacrylate, cyclohexyl methacrylate, dodecyl methacrylate, etc., epoxy group-containing methacrylates such as glycidyl methacrylate, maleimide, N-methylmaleimide, N-phenylmaleimide, etc. Body, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, phthalic acid, itaconic acid and other α, β-unsaturated carboxylic acids and their anhydrides. Of these, acrylonitrile is preferable from the viewpoint of excellent appearance when formed into a molded product.

  The rubbery polymer copolymerizable with the styrenic monomer includes polybutadiene, polyisoprene, styrene / butadiene random copolymer and block copolymer; acrylonitrile / butadiene copolymer; alkyl acrylate ester or methacrylic ester. Copolymer of acid alkyl ester and butadiene; diene copolymer such as butadiene / isoprene copolymer; ethylene / propylene random copolymer and block copolymer; ethylene / butene random copolymer and block copolymer Copolymers of ethylene and α-olefins such as; ethylene / methacrylate copolymers; copolymers of ethylene and unsaturated carboxylic esters such as ethylene / butyl acrylate copolymers; ethylene / vinyl acetate copolymers, etc. Of ethylene and aliphatic vinyl Polymer; Ethylene, propylene and non-conjugated diene terpolymer such as ethylene / propylene / hexadiene copolymer; Acrylic rubber such as polybutyl acrylate; Polyorganosiloxane rubber component and polyalkyl (meth) acrylate rubber component are separated Examples thereof include a composite rubber (hereinafter, sometimes referred to as IPN type rubber) having a structure intertwined so as not to be able to be performed. Among these, acrylonitrile / butadiene copolymer is preferable from the viewpoint of excellent bending characteristics.

  Specific examples of such styrene resins include, for example, polystyrene, styrene / butadiene / styrene copolymer (SBS), hydrogenated styrene / butadiene / styrene copolymer (hydrogenated SBS), hydrogenated styrene / isoprene, Styrene copolymer (SEPS), high impact polystyrene resin (HIPS), acrylonitrile / styrene copolymer (AS), acrylonitrile / butadiene / styrene copolymer (ABS), methyl methacrylate / butadiene / styrene copolymer (MBS) , Methyl methacrylate / acrylonitrile / butadiene / styrene copolymer (MABS), acrylonitrile / acrylic rubber / styrene copolymer (AAS), acrylonitrile / ethylene propylene rubber / styrene copolymer (AES), styrene / IPN rubber copolymer Resin coalesced, and the like. Among these, AS and ABS are preferable from the viewpoint of impact resistance, bending characteristics, and heat resistance. These styrene resins are used alone or in combination.

As the styrenic resin, those produced by a known polymerization method may be used, or commercially available products may be used.
In the thermoplastic resin composition of the present invention, the mass ratio of the polylactic acid resin and the styrene resin (polylactic acid resin / styrene resin) needs to be 95/5 to 40/60. It is preferably 10-60 / 40, more preferably 90 / 10-75 / 25. If the proportion of the styrene resin is less than the above range, the resulting thermoplastic resin composition will have insufficient impact resistance. On the other hand, when the ratio of the styrene resin is too much than the above range, the ratio of the polylactic acid resin is decreased, so that a thermoplastic resin composition having a small effect of reducing the environmental load is obtained.

  The thermoplastic resin composition of the present invention preferably contains a crystal nucleating agent for the purpose of further promoting crystallization. Examples of the crystal nucleating agent include organic amide compounds, organic hydrazide compounds, organic sulfonates, phthalocyanine compounds, melamine compounds, and organic phosphonates.

  Examples of organic amide compounds and organic hydrazide compounds include ethylene bisoleic acid amide, methylene bisacrylic acid amide, ethylene bisacrylic acid amide, hexamethylene bis-9, 10-dihydroxystearic acid bisamide, p-xylylene bis-9, 10 dihydroxystearin. Acid amide, decanedicarboxylic acid dibenzoylhydrazide, hexanedicarboxylic acid dibenzoylhydrazide, 1,4-cyclohexanedicarboxylic acid dicyclohexylamide, 2,6-naphthalenedicarboxylic acid dianilide, N, N ′, N ″ -tricyclohexyltrimesic acid amide , Trimesic acid tris (t-butylamide), 1,4-cyclohexanedicarboxylic acid dianilide, 2,6-naphthalenedicarboxylic acid dicyclohexylamide, N, N'-dibenzoyl- 1,4-diaminocyclohexane, N, N′-dicyclohexanecarbonyl-1,5-diaminonaphthalene, ethylenebisstearic acid amide, N, N′-ethylenebis (12-hydroxystearic acid) amide, dibenzoyl octanedicarboxylate Among them, N, N ′, N ″ -tricyclohexyltrimesic acid amide, N, N′-ethylenebis (12-hydroxystearic acid) are preferable in view of dispersibility in the resin and heat resistance. Amides and octanedicarboxylic acid dibenzoyl hydrazides are preferred.

  Various organic sulfonates such as sulfoisophthalate can be used. Of these, dimethyl metal salt of 5-sulfoisophthalic acid is preferable from the viewpoint of the effect of promoting crystallization. Further, barium salt, calcium salt, strontium salt, potassium salt, rubidium salt, sodium salt and the like of dimethyl 5-sulfoisophthalate are preferable, and dimethyl potassium 5-sulfoisophthalate and dimethylbarium 5-sulfoisophthalate are particularly preferable.

  Various phthalocyanine compounds can be used. Especially, it is preferable to use a transition metal complex from the point of the crystallization promotion effect, and copper phthalocyanine is especially preferable. Various compounds can be used as the melamine compound, but melamine cyanurate is preferably used from the viewpoint of the crystallization promoting effect. As the organic phosphonic acid compound, phenylphosphonate is preferred from the viewpoint of the crystallization promoting effect. Of these, zinc phenylphosphonate is particularly preferred from the viewpoint of the effect of promoting crystallization.

  These crystal nucleating agents can be used alone or in combination of two or more. In addition, various inorganic crystal nucleating agents may be used in combination with such an organic crystal nucleating agent.

  The content of the crystal nucleating agent is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the total amount of the polylactic acid resin and the styrene resin. is there. If it is less than 0.1 part by mass, the crystallization promoting effect may be poor. On the other hand, if it exceeds 10 parts by mass, the effect as a crystal nucleating agent is saturated, which is not only economically disadvantageous, but also heat resistance is reduced, and the residue after biodegradation is increased, so it is also environmentally friendly. It may not be preferable.

  In addition to the (meth) acrylic acid ester compound added when the polylactic acid resin is crosslinked, the thermoplastic resin composition of the present invention enhances the compatibility between the polylactic acid resin and the styrene resin to improve impact resistance. For the purpose of improving, it is preferable to blend an acrylic resin other than the (meth) acrylic acid ester compound. Examples of such acrylic resins include (meth) acrylic copolymers, copolymers of styrene monomers and (meth) acrylic monomers, and the like. Among these, a (meth) acrylic copolymer is preferable because compatibility can be remarkably improved and mechanical properties and heat resistance can be improved.

  The (meth) acrylic copolymer is obtained by polymerizing a (meth) acrylic monomer alone or by copolymerizing two or more (meth) acrylic monomers. Examples of (meth) acrylic monomers include alkyl groups (including cycloalkyl groups) such as methyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and isobornyl methacrylate. Examples thereof include (meth) acrylic acid alkyl ester monomers having 1 to 18 carbon atoms, (meth) acrylic acid aryl ester monomers such as phenyl methacrylate, and (meth) acrylic acid aralkyl ester monomers such as benzyl methacrylate. . Of these, ethyl methacrylate and methyl acrylate are preferred.

  The copolymer of a styrene monomer and a (meth) acrylic monomer is obtained by copolymerizing a styrene monomer and a monomer constituting the (meth) acrylic copolymer. Examples of styrenic monomers include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, vinylnaphthalene, methoxystyrene, Examples thereof include styrene derivatives of monobromostyrene, dibromostyrene, fluorostyrene, and tribromostyrene. Of these, styrene, α-methylstyrene and the like are preferable. These may be used alone or in combination of two or more.

  As content in the thermoplastic resin of such an acrylic resin, it is preferable that it is 0.1-10 mass parts with respect to 100 mass parts of total amounts of a polylactic acid-type resin and a styrene resin, More preferably, 0.5 to 5 parts by mass. If it is less than 0.1 parts by mass, the impact resistance improving effect may be poor. On the other hand, if it exceeds 10 parts by mass, the impact resistance may be reduced.

  The thermoplastic resin composition of the present invention is sometimes referred to as a reactive compound (hereinafter referred to as “reactive compound”) for the purpose of improving durability and maintaining heat resistance stably for a long period of time. ) Is preferably contained. In the present invention, the reactive compound is at least one selected from a carbodiimide compound, an epoxy compound, and an oxazoline compound.

  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. Among them, from the viewpoint of durability, N, N′-di-2,6-diisopropylphenylcarbodiimide, 1,3,5-triisopropyl-phenylene-2,4-diisocyanate, poly (4,4′- Dicyclohexylmethanecarbodiimide) is preferred. 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.
Although it does not specifically limit as an epoxy compound, For example, the epoxy compound containing bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolak glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, etc. is preferable.

Although it does not specifically limit as an oxazoline compound, For example, the oxazoline compound containing 2-isopropenyl-2-oxazoline is the most preferable.
As content in the thermoplastic resin of such a reactive compound, it is preferable that it is 0.1-10 mass parts with respect to 100 mass parts of total amounts of a polylactic acid-type resin and a styrene resin, and is 0.00. It is more preferably 5 to 5 parts by mass. If the content is less than 0.1 parts by mass, the intended durability (moisture heat resistance) improvement effect may be poor. On the other hand, when the content exceeds 10 parts by mass, it is not economically preferable, heat resistance may be lowered, and color tone may be greatly impaired.

  The means for further mixing the reactive compound with the resin composition containing the polylactic acid-based resin and the styrene-based resin is not particularly limited, and examples thereof include a method of melt-kneading using a uniaxial or biaxial extruder. be able to. In order to improve the kneading state, it is preferable to use a twin screw extruder. The kneading temperature is preferably {[melting point of polylactic acid resin] +5} ° C. to {[melting point of polylactic acid resin] +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 the time is longer than this time, the resin may be decomposed or colored.

  The thermoplastic resin composition of the present invention includes pigments, heat stabilizers, antioxidants, inorganic fillers, plant fibers, reinforcing fibers, weathering agents, lubricants, mold release agents, and antistatic materials, as long as the properties are not impaired. Additives such as additives, plasticizers, impact agents other than the above crystal nucleating agents, and compatibilizers can be contained.

  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. 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. In addition, it does not specifically limit as a method of mixing said additive with the resin composition of this invention.

  When using the thermoplastic resin composition of this invention, you may use as a resin composition which further mix | blended resin other than a polylactic acid-type resin and a styrene resin. Examples of such a resin include, but are not limited to, polyolefins, polyesters, polyamides, polycarbonates, poly (methyl) methacrylates, poly (acrylonitrile / butadiene / styrene) copolymers, 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 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. In addition, the method of mix | blending (mixing) these resin with the thermoplastic resin composition of this invention is not specifically limited.

  Next, the manufacturing method of the thermoplastic resin composition of this invention is demonstrated. Examples of the production method include a method in which raw materials are mixed with a Henschel mixer, supplied to an extruder, melt kneaded, and pelletized. In addition, when mixing a powder and a pellet collectively, it may be difficult to disperse | distribute uniformly within a Henschel mixer. In such a case, there is a method in which a viscous liquid additive is added as a blend oil in a small amount to be uniformly dispersed. As such a liquid additive, anything may be used as long as it does not impair the properties of the thermoplastic resin composition of the present invention, but from the environmental viewpoint, an additive derived from biomass is preferable. For example, biomass-derived glycerol fatty acid esters and polyglycerol fatty acid esters are desirable.

  The thermoplastic resin composition of the present invention is produced by injection molding, blow molding, extrusion molding, inflation molding, injection blow molding, foamed sheet molding, and molding methods such as vacuum molding, pressure molding, and vacuum / pressure molding after sheet processing. Various molded bodies can be obtained. That is, as a molded body formed by molding the thermoplastic resin of the present invention, a molded body formed by injection molding, or a film, a sheet formed by extrusion molding, and a molded body formed by processing these films or sheets. Alternatively, a hollow body formed by blow molding, a molded body processed from the hollow body, and the like can be given. 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 for obtaining the molded object 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, for example, 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 thermoplastic resin composition is decomposed, and the strength of the resulting molded product is reduced or colored. Are likely to occur and both are not preferred.

  The thermoplastic 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 thermoplastic resin composition or higher (the thermoplastic resin composition It is preferable to hold the molded body for a certain period of time in a mold kept at a melting point of −40) ° C. or lower and then remove it from the mold. Moreover, even if it is the molded object taken out from the metal mold | die without taking such a method, this molded object is more than the glass transition temperature of a thermoplastic resin composition, (melting | fusing point-40 of thermoplastic resin composition) Crystallization can be promoted by heat treatment at a temperature not higher than ° C.

  Specific examples of the molded body of the present invention include personal computer casing parts and casings, mobile phone casing parts and casings, other OA equipment casing parts, resin parts for electrical appliances such as connectors; bumpers, instrument panels , Console boxes, garnishes, door trims, ceilings, floors, plastic parts for automobiles such as panels around engines, agricultural materials such as containers and cultivation containers, and plastic parts for agricultural machinery; marine products such as floats and processed fishery products containers Resin parts for use; dishes, food containers such as dishes, cups, and spoons; medical resin parts such as syringes and infusion containers; resin parts for housing, civil engineering, and building materials such as drain materials, fences, storage boxes, and distribution boards for construction; Resin parts for greening materials such as flowerbed bricks and flowerpots; Resin parts for leisure and miscellaneous goods such as cooler boxes, fan fans, toys; ballpoint pens, rulers, clicks Stationery resin parts, etc. and the like.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.
The measuring methods used for the evaluation of the resin compositions of Examples and Comparative Examples are as follows.
(1) MFR
According to JIS K 7210 (test condition D), the measurement was performed at 190 ° C. and a load of 21.1 N.
(2) Bending characteristics and bending strength Bending strength was measured according to ISO178 using the obtained test piece. In the present invention, a material having a bending strength of 70 MPa or more can be practically used.
-Flexural modulus The flexural modulus was measured according to ISO178 using the obtained test piece. In the present invention, a material having a flexural modulus of 3.0 GPa or more can be practically used.
-Bending fracture strain The bending fracture strain was measured according to ISO178 using the obtained test piece. In the present invention, those having a bending fracture strain of 5.0% or more are assumed to be practically usable.
(3) Impact resistance Charpy impact strength measured according to ISO 179-1 was used using the obtained test piece. In the present invention, a material having a Charpy impact strength of 5.0 kJ / m ² or more can be practically used.
(4) Heat resistance Using the obtained test piece, the deflection temperature under load measured with a load of 0.45 MPa was used according to ISO75-1. In the present invention, those having a deflection temperature under load of 90 ° C. or more are assumed to be practically usable.
(5) Durability (Bending strength retention)
Two test pieces obtained were prepared, and one was measured for bending strength (bending strength before wet heat treatment) by the same method as in (2) above. The other was subjected to 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 then the bending strength (bending strength after the wet heat treatment) was measured by the same method as in (2) above. The bending strength retention was calculated from the following formula.
(Bending strength retention) (%) = [(Bending strength after wet heat treatment) / (Bending strength before wet heat treatment)] × 100
And it evaluated on the following references | standards.
A: Bending strength retention is 95% or more.
○: Bending strength retention is 85% or more and less than 95%.
Δ: 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 of 85% 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 (A)
・ (A-1)
Product name “Nature Works 4032D” manufactured by Cargill Dow (weight average molecular weight 160000, MFR: 3 g / 10 min, melting point: 168 ° C., D-form content: 1.4 mol%)
・ (A-2)
Product name “Nature Works 3001D” manufactured by Cargill Dow (weight average molecular weight 100,000, MFR: 10 g / 10 min, melting point: 168 ° C., D-form content: 1.4 mol%)
・ (A-3)
Product name “Nature Works 4042D” manufactured by Cargill Dow (weight average molecular weight 165000, MFR: 3 g / 10 min, melting point: 168 ° C., D-form content: 4.0 mol%)
(2) Styrenic resin (B)
・ (B-1)
ABS resin (trade name “Bulksum TM30” manufactured by UMG ABS)
・ (B-2)
ABS resin (Daicel Polymer Co., Ltd., trade name “Cebian 466MD”)
(3) Peroxide (C)
・ (C-1)
Di-t-butyl peroxide (Nippon Yushi Co., Ltd., trade name "Perbutyl D")
(4) (Meth) acrylic acid ester compound (D)
・ (D-1)
Ethylene glycol dimethacrylate (Nippon Yushi Co., Ltd., trade name “Blemmer PDE-50”)
(5) Silane compound (E)
・ (E-1)
Vinyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., trade name “KBM-1003”)
(6) Acrylic resin (F)
・ (F-1)
Copolymer of ethyl methacrylate and methyl acrylate (manufactured by Mitsubishi Rayon Co., Ltd., trade name “Acrypet VH-001”)
・ (F-2)
Copolymer of ethyl methacrylate and methyl acrylate (manufactured by Mitsubishi Rayon Co., Ltd., trade name “Acrypet MD-001”)
(7) Crystal nucleating agent (G)
・ (G-1)
Dimethyl barium 5-sulfoisophthalate (manufactured by Takemoto Yushi Co., Ltd., trade name “LAK-403”)
・ (G-2)
5-Dimethyl potassium sulfoisophthalate (manufactured by Takemoto Yushi Co., Ltd., trade name “LAK-301”)
(8) Reactive compound (H)
・ (H-1)
Carbodiimide compound (N, N′-di-2,6-diisopropylphenylcarbodiimide) (manufactured by Matsumoto Yushi Co., Ltd., trade name “EN-160”)
・ (H-2)
Carbodiimide compound [poly (4,4′-dicyclohexylmethanecarbodiimide)] (Nisshinbo Co., Ltd., trade name “LA-1”)
(9) Plasticizer / polyglycerin fatty acid ester (manufactured by Taiyo Kagaku Co., Ltd., trade name “Tirabazole VR-01”) (hereinafter sometimes referred to as “VR-01”)
Medium-chain fatty acid triglyceride (Riken Vitamin Co., Ltd., trade name “Actor M-1”) (hereinafter sometimes referred to as “M-1”)
(Preparation of cross-linked polylactic acid resin)
Using a twin-screw extruder (trade name “TEM37BS type” manufactured by Toshiba Machine Co., Ltd.), (A-1) is supplied from the base supply port of the extruder at the ratio shown in Table 1, and shown in Table 1 from the middle of kneading. A solution in which (C-1), (D-1), (E-1), and (M-1) are mixed at a ratio is injected, and the barrel temperature is 190 ° C., the screw speed is 180 rpm, and the discharge rate is 15 kg / h. Then, melt extrusion was performed while venting was effective. 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 pellets to form crosslinked polylactic acid resins (A-4) to (A- 11) 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、ポリ乳酸系樹脂として、８５質量部の（Ａ−１）、スチレン系樹脂として、１５質量部の（Ｂ−１）、可塑剤として０．５質量部のＶＲ−０１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。

Example 1
Using a twin screw extruder (trade name “TEM37BS type” manufactured by Toshiba Machine Co., Ltd.), as a polylactic acid resin, 85 parts by mass of (A-1), as a styrene resin, 15 parts by mass of (B-1), 0.5 parts by mass of VR-01 as a plasticizer is dry blended and supplied from the root supply port of the extruder, and the vent is effective 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. Melt extrusion was carried out. 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 “EC-100 type” manufactured by Toshiba Machine Co., Ltd.), an ISO-compliant test piece was produced in a molding cycle of 50 seconds while adjusting the mold surface temperature to 90 ° C.

(Examples 2 to 22),
Resin in the same manner as in Example 1 except that the types and blending amounts of the polylactic acid resin, styrene resin, acrylic resin, crystal nucleating agent, and reactive compound were changed as shown in Table 2 and Table 3. A pellet of the composition was obtained.

And the obtained pellet was injection-molded similarly to Example 1, and the test piece was produced.
(Examples 23 to 31)
Resin in the same manner as in Example 1 except that cross-linked polylactic acid resins (A-4) to (A-11) were used as polylactic acid resins instead of (A-1) as shown in Table 3. A pellet of the composition was obtained.
And the obtained pellet was injection-molded similarly to Example 1, and the test piece was produced.
Comparative Examples 1-12
The resin composition was changed in the same manner as in Example 1 except that the types and amounts of the polylactic acid resin, styrene resin, acrylic resin, crystal nucleating agent, and reactive compound were changed as shown in Table 4. Pellets were obtained.

And the obtained pellet was injection-molded similarly to Example 1, and the test piece was produced.
The evaluation result of the test piece which consists of a resin composition obtained in Examples 1-31 and Comparative Examples 1-12 is shown to Tables 2-4.

表２〜３より明らかなように、実施例１〜３４で得られた熱可塑性樹脂組成物は、曲げ破断歪が１０％を超えるものであって、曲げ特性に優れ、耐衝撃性、耐熱性、耐久性にも優れるものであった。

As is apparent from Tables 2 and 3, the thermoplastic resin compositions obtained in Examples 1 to 34 have a bending fracture strain of more than 10%, have excellent bending properties, impact resistance, and heat resistance. It was also excellent in durability.

The thermoplastic resin compositions of Examples 23 to 31 using a crosslinked polylactic acid resin were excellent in heat resistance.
The thermoplastic resin compositions of Examples 1 to 22 and 31 using a crystal nucleating agent were excellent in heat resistance.

Among these, the thermoplastic resin composition of Example 31 in which a crosslinked polylactic acid-based resin was used and a crystal nucleating agent was used resulted in particularly excellent heat resistance.
The thermoplastic resin compositions of Examples 2-31 using a reactive compound were particularly excellent in durability as compared with Example 1 in which no reactive compound was used.

  The thermoplastic resin compositions of Examples 3 to 31 using an acrylic resin were particularly excellent in impact resistance as compared with the thermoplastic resin composition of Example 2 containing no acrylic resin.

  For the thermoplastic resin compositions of Comparative Examples 1, 3, and 4, a polylactic acid resin having a weight average molecular weight in the range specified in the present invention was used, but no styrene resin was used. Therefore, the obtained thermoplastic resin composition has a low bending fracture strain, inferior bending properties, and inferior impact resistance.

  For the thermoplastic resin composition of Comparative Example 2, a polylactic acid resin having a weight average molecular weight of 100,000 was lower than the range defined in the present invention, and no styrene resin was used. Therefore, the bending fracture strain is low, the bending properties are inferior, and the impact resistance is also inferior.

  In the thermoplastic resin compositions of Comparative Examples 5 and 7, a polylactic acid resin having a weight average molecular weight in the range specified in the present invention was used, but no styrene resin was used. Therefore, the obtained thermoplastic resin composition has a low bending fracture strain and is inferior in bending properties, and although an acrylic resin is used, it is inferior in impact resistance.

  For the thermoplastic resin composition of Comparative Example 6, a polylactic acid resin having a weight average molecular weight of 100,000 was lower than the range defined in the present invention, and no styrene resin was used. Therefore, the bending fracture strain is low and the bending properties are inferior, and the acrylic resin is used, but the impact resistance is also inferior.

  As the thermoplastic resin composition of Comparative Example 8, a polylactic acid resin having a weight average molecular weight in the range specified in the present invention was used, but the content of the styrene resin was too small. Therefore, the bending fracture strain is low and the bending properties are inferior, and the acrylic resin is used, but the impact resistance is also inferior.

  The thermoplastic resin composition of Comparative Example 9 had an excessive content of polylactic acid resin. Therefore, the values of bending strength and bending elastic modulus are low, the heat resistance is inferior, and the load on the environment is large.

  For the thermoplastic resin composition of Comparative Example 10, only a styrene resin was used without using a polylactic acid resin. Therefore, the values of bending strength and bending elastic modulus are low, the heat resistance is inferior, and the load on the environment is large.

  As the thermoplastic resin compositions of Comparative Examples 11 and 12, a polylactic acid resin having a molecular weight smaller than the weight average molecular weight defined in the present invention was used. Therefore, the bending fracture strain is low and the bending properties are inferior, and the acrylic resin is used, but the impact resistance is also inferior.

Claims (6)

  A polylactic acid resin having a weight average molecular weight of 150,000 or more and a styrene resin are contained, and the mass ratio of the polylactic acid resin to the styrene resin is polylactic acid resin / styrene resin = 95/5 to 40/60. A thermoplastic resin composition characterized in that it is present.   The thermoplastic resin composition according to claim 1, wherein the polylactic acid resin is a crosslinked polylactic acid resin.   The crosslinked polylactic acid-based resin is composed of 0.01 to 10 parts by weight of peroxide, 100 parts by weight of polylactic acid-based resin, (meth) acrylic acid ester compound and / or alkoxy group, acrylic group, methacrylic group, vinyl. The thermoplastic resin composition according to claim 2, wherein the thermoplastic resin composition is obtained by blending 0.01 to 5 parts by mass of a silane compound having two or more functional groups selected from a group.   The thermoplastic resin composition according to any one of claims 1 to 3, wherein the styrenic resin is an acrylonitrile / styrene copolymer and / or an acrylonitrile / butadiene / styrene copolymer.   Characterized by containing 0.1 to 10 parts by mass of at least one compound selected from a carbodiimide compound, an epoxy compound and an oxazoline compound with respect to 100 parts by mass of the total amount of the polylactic acid resin and the styrene resin. The thermoplastic resin composition according to any one of claims 1 to 4. The molded object formed by shape | molding the thermoplastic resin composition in any one of Claims 1-5.