JP5397993B2 - Thermoplastic resin composition and molded body - Google Patents

Description

  The present invention relates to a thermoplastic resin composition and a molded body obtained by molding the thermoplastic resin composition.

  Thermoplastic resins are widely used in various applications as materials having excellent properties such as mechanical properties, heat resistance, and moldability, but most of the raw materials are components derived from petroleum. However, in recent years, due to growing social interest in global environmental and resource issues, non-petroleum-derived components such as renewable plant-derived components are used as raw materials for thermoplastic resins in place of conventional petroleum-derived components. It is hoped to do. Attempts have been made to utilize polylactic acid polymers obtained by polymerizing lactic acid produced from corn or the like, which is one of such non-petroleum-derived components. Attempts have been made to improve the flexibility, durability, and heat resistance of polylactic acid polymers in order to form polylactic acid polymers into soft films and sheets and use them as packaging materials for foods and the like. .

  As a method for imparting flexibility to the polylactic acid polymer, for example, an attempt has been made to add a plasticizer having a plasticizing effect to the polylactic acid polymer. However, a molded article of a polylactic acid polymer obtained by adding such a plasticizer is deteriorated in molding appearance and flexibility over time due to crystallization of the polylactic acid polymer or bleeding out of the plasticizer. Have problems such as poor heat resistance. In addition, although an attempt has been made to use an amorphous polylactic acid polymer as a further improvement, although crystallization of the polylactic acid polymer can be suppressed, bleedout of the plasticizer cannot be suppressed. There is a problem that the molding appearance and flexibility decrease with time.

  In order to solve the above problems, for example, Patent Document 1 proposes a thermoplastic resin composition containing a polylactic acid polymer and a (meth) acrylate polymer having a mass average molecular weight of 30,000 or less. However, this method cannot be said to have sufficient flexibility, durability, and heat resistance of the obtained molded product.

JP 2003-286401 A

  An object of the present invention is to provide a thermoplastic resin composition having excellent moldability, which provides a molded article having excellent flexibility, durability, and heat resistance.

The present invention, hydroxycarboxylic acid polymer (A) and obtained by polymerizing a monomer component (b) containing methyl acrylated preparative (b1) more than 90 wt%, the glass transition temperature of at 60 ° C. or less And a thermoplastic resin composition containing an acrylate polymer (B) having a mass average molecular weight of 300,000 to 1,000,000.

  Moreover, this invention is a molded object obtained by shape | molding the said thermoplastic resin composition.

  According to the present invention, the thermoplastic resin composition is excellent in moldability, and the resulting molded article is excellent in flexibility, durability, and heat resistance. Therefore, it can be used as a resin material for various applications. In particular, by forming into a film or sheet, it can be suitably used for industrial and food packaging materials.

  As the hydroxycarboxylic acid polymer (A) of the present invention, a known hydroxycarboxylic acid polymer can be used, and examples thereof include a polylactic acid polymer.

  The polylactic acid polymer is obtained by polymerizing the monomer component (a) containing lactic acid (a1) as a main component. Examples of lactic acid include D-lactic acid and L-lactic acid. These lactic acids (a1) may be used individually by 1 type, and may use 2 or more types together.

The monomer component (a) may contain another copolymerizable monomer (a2) in addition to lactic acid (a1) as long as the performance as a polylactic acid polymer is not impaired. Examples of the other monomer (a2) include aliphatic hydroxycarboxylic acid, aliphatic diol, and aliphatic dicarboxylic acid. These other monomers (a2) may be used individually by 1 type, and may use 2 or more types together.
Examples of the form of copolymerization include random copolymerization, block copolymerization, and graft copolymerization.

  The composition of the monomer component (a) is 50% by mass or more of lactic acid (a1) and 50% by mass or less of the other monomer (a2) in 100% by mass of the total monomer component (a). More preferably, the lactic acid (a1) is 70% by mass or more, and the other monomer (a2) is 30% by mass or less, and the lactic acid (a1) is 90% by mass or more. More preferably, a2) is 10% by mass or less.

The crystallinity of the polylactic acid-based polymer is not particularly limited, and may be crystalline or amorphous. The crystallinity can be confirmed with a polarizing microscope or the like.
Examples of the crystalline polylactic acid polymer include poly L-lactic acid (PLLA) which is a polymer of L-lactic acid. As an amorphous polylactic acid-type polymer, poly DL-lactic acid (PDLLA) which is a copolymer of D-lactic acid and L-lactic acid is mentioned, for example.

  As the polylactic acid polymer, a commercially available polylactic acid polymer may be used. Examples of commercially available crystalline polylactic acid-based polymers include “Lacia H-100” (trade name, manufactured by Mitsui Chemicals, Inc.). Examples of commercially available amorphous polylactic acid polymers include “Lacia H-280” (trade name, manufactured by Mitsui Chemicals) and “4060D” (trade name, manufactured by Nature Works). These polylactic acid-type polymers may be used individually by 1 type, and may use 2 or more types together.

The (meth) acrylate polymer (B) of the present invention has a glass transition temperature of 60 ° C. or lower, preferably from −40 to 60 ° C., and more preferably from −20 to 40 ° C.
When the glass transition temperature of the (meth) acrylate polymer (B) is −40 ° C. or higher, the resulting molded article is excellent in durability and heat resistance. Moreover, it is excellent in the softness | flexibility of the molded object obtained as the glass transition temperature of a (meth) acrylate type polymer (B) is 60 degrees C or less.
In the case of a homopolymer, the glass transition temperature of the (meth) acrylate polymer (B) is based on a numerical value described in a polymer handbook (4th edition, published by John Wiley & Sons Inc.). In the case of a copolymer, it is calculated using the numerical values described in the polymer handbook (4th edition, published by John Wiley & Sons Inc.) and the formula of FOX.
In the present invention, “(meth) acrylate” means “acrylate” or “methacrylate”.

In order to obtain the (meth) acrylate polymer (B) of the present invention, a monomer component (b) having (meth) acrylate (b1) as a main component, the glass transition temperature of the homopolymer is 60 ° C. or lower. ) May be polymerized.
Examples of (meth) acrylate (b1) include methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, cyclohexyl acrylate, benzyl acrylate, phenyl acrylate, and dimethylaminoethyl. Acrylate such as acrylate, cyanoethyl acrylate, cyanobutyl acrylate, 2,2,2-trifluoroethyl acrylate, heptadecafluorodecyl acrylate; n-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, benzyl methacrylate, dimethylaminoethyl Methacrylate, cyanoethyl methacrylate, cyanobutyl methacrylate, 2,2,2-trifluoroethyl Methacrylate, methacrylates such as heptadecafluorodecyl methacrylate. These (meth) acrylates (b1) may be used alone or in combination of two or more.
Among these (meth) acrylates (b1), acrylate is preferable, methyl acrylate, ethyl acrylate, and n-butyl acrylate are more preferable, and methyl acrylate is still more preferable from the viewpoint of flexibility of the obtained molded body.

  The monomer component (b) is another monomer that can be copolymerized in addition to the (meth) acrylate (b1) in the range where the glass transition temperature of the (meth) acrylate polymer (B) is 60 ° C. or lower. (B2) may be included. Examples of the other monomer (b2) include (meth) acrylates in which the glass transition temperature of homopolymers such as methyl methacrylate exceeds 60 ° C .; aromatic vinyl monomers such as styrene and α-methylstyrene; acrylonitrile, etc. Vinyl cyanide monomers; Epoxy group-containing monomers such as glycidyl methacrylate; Acid anhydride group-containing monomers such as maleic anhydride; Diene monomers such as butadiene; Ethylene, propylene, 1-hexene, etc. Examples include olefinic monomers. These other monomers (b2) may be used individually by 1 type, and may use 2 or more types together.

  The composition of the monomer component (b) is 50% by mass of (meth) acrylate (b1) and 50% by mass of the other monomer (b2) in 100% by mass of the total monomer component (b). The (meth) acrylate (b1) is preferably 70% by mass or more, the other monomer (b2) is more preferably 30% by mass or less, and the (meth) acrylate (b1) is 90% by mass. % Of the other monomer (b2) is more preferably 10% by mass or less.

As a polymerization method for obtaining the (meth) acrylate polymer (B) of the present invention, a known polymerization method may be used. Examples of the polymerization method include a radical polymerization method, an anionic polymerization method, a cationic polymerization method, and a transition metal catalyst polymerization method.
As a polymerization system for obtaining the (meth) acrylate polymer (B) of the present invention, a known polymerization system may be used. Examples of the polymerization system include bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization.
The polymerization form for obtaining the (meth) acrylate polymer (B) of the present invention may be any of batch type, semi-batch type and continuous type.

The polymerization temperature for obtaining the (meth) acrylate polymer (B) of the present invention is 0 to 150 ° C., although it depends on the type of the monomer component (b), the polymerization initiator, and the polymerization system. Is preferable, and it is preferable that it is 50-90 degreeC.
The polymerization time for obtaining the (meth) acrylate polymer (B) of the present invention is usually 1 to 10 hours, although it depends on the type of the monomer component (b) and the polymerization initiator and the polymerization system. .
The polymerization atmosphere for obtaining the (meth) acrylate polymer (B) of the present invention is not particularly limited, but is preferably a nitrogen atmosphere from the viewpoint of polymerization efficiency.

  In the polymerization for obtaining the (meth) acrylate polymer (B) of the present invention, a polymerization aid such as a polymerization initiator, a dispersant, a dispersion aid, an emulsifier, and a chain transfer agent is added as necessary. Also good.

Examples of the polymerization initiator include t-butyl hydroperoxide, cumene hydroperoxide, lauroyl peroxide, benzoyl peroxide, di-t-butyl peroxide, di-t-amyl peroxide, and di-t-hexyl peroxide. Organic peroxides such as oxide, t-butylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxybenzoate, diisopropylperoxycarbonate; potassium persulfate, Persulfates such as ammonium persulfate; azo compounds such as azobisisobutyronitrile and azobis-2,4-dimethylvaleronitrile; redox initiators in combination with the above organic peroxides or the above persulfates and reducing agents Is mentioned. These polymerization initiators may be used alone or in combination of two or more.
Among these polymerization initiators, from the viewpoint of polymerization efficiency, t-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide, t-butyl peroxy-2-ethylhexanoate, potassium persulfate, ammonium persulfate, Azobisisobutyronitrile and azobis-2,4-dimethylvaleronitrile are preferred.

Examples of the dispersant include polyvinyl alcohol, sodium polyacrylate, and polyethylene oxide. These dispersing agents may be used individually by 1 type, and may use 2 or more types together.
Examples of the dispersion aid include sodium sulfate, sodium carbonate, hydrogen peroxide, and boric acid. These dispersing aids may be used alone or in combination of two or more.

  Known emulsifiers can be used as the emulsifier, and examples thereof include an anionic emulsifier, a cationic emulsifier, and a nonionic emulsifier. These emulsifiers may be used individually by 1 type, and may use 2 or more types together.

  Examples of the chain transfer agent include octyl mercaptan and dodecyl mercaptan. These chain transfer agents may be used individually by 1 type, and may use 2 or more types together.

The (meth) acrylate polymer (B) of the present invention has a mass average molecular weight of 100,000 or more, preferably 100,000 to 5,000,000, more preferably 200,000 to 2,000,000, and 300,000. More preferably, it is ˜1 million.
When the weight average molecular weight of the (meth) acrylate polymer (B) is 100,000 or more, the resulting molded article is excellent in heat resistance. Moreover, it is excellent in the moldability of a thermoplastic resin composition as the mass average molecular weight of a (meth) acrylate type polymer (B) is 5 million or less.

  The thermoplastic resin composition of the present invention contains a hydroxycarboxylic acid polymer (A) and a (meth) acrylate polymer (B).

The composition of the thermoplastic resin composition of the present invention is hydroxycarboxylic acid polymer (A) 1 in a total of 100% by mass of hydroxycarboxylic acid polymer (A) and (meth) acrylate polymer (B). It is preferable that it is -99 mass%, (meth) acrylate type polymer (B) 1-99 mass%, hydroxycarboxylic acid type polymer (A) 10-80 mass%, (meth) acrylate type polymer (B 20) to 90% by mass, more preferably 20 to 60% by mass of the hydroxycarboxylic acid polymer (A), and 40 to 80% by mass of the (meth) acrylate polymer (B).
When the hydroxycarboxylic acid polymer (A) is 1% by mass or more, the resulting molded article is excellent in durability and heat resistance. Further, when the hydroxycarboxylic acid polymer (A) is 99% by mass or less, the resulting molded article is excellent in flexibility.
When the (meth) acrylate polymer (B) is 1% by mass or more, the resulting molded article is excellent in flexibility. Moreover, it is excellent in durability and heat resistance of the molded object obtained as a (meth) acrylate type polymer (B) is 99 mass% or less.

  The thermoplastic resin composition of the present invention is optionally added with other thermoplastic resins, flexibility-imparting agents, antioxidants, light stabilizers, flame retardants, etc .; glass fiber, carbon fiber, talc, carbonic acid Fillers such as calcium, kenaf and bacterial cellulose; may contain pigments.

Other thermoplastic resins include, for example, acrylic resins such as polymethyl methacrylate and methyl methacrylate-acrylate copolymers; polystyrene, high impact polystyrene, acrylonitrile-styrene copolymers, acrylonitrile-butadiene-styrene copolymers. , Styrene resins such as styrene-butadiene copolymer, hydrogenated styrene-butadiene copolymer; polypropylene, low density polyethylene, linear low density polyethylene, high density polyethylene, ethylene-propylene copolymer, cyclic olefin-containing polymer Olefin resins such as coalescence; Aromatic polyester such as polyethylene terephthalate, polytrimethylene glycol terephthalate, polybutylene terephthalate; Aliphatic poly, such as polycaprolactone, polybutylene succinate Ester; polycarbonates; cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose esters such as cellulose acetate butyrate. These other thermoplastic resins may be used individually by 1 type, and may use 2 or more types together.
The content of other thermoplastic resins is preferably 50% by mass or less in 100% by mass of the total thermoplastic resin composition.

  Examples of the flexibility-imparting agent include polyhydric alcohol plasticizers, polybasic acid ester plasticizers, polyester plasticizers, phosphate ester plasticizers, epoxy plasticizers, fatty acid plasticizers, and sulfonic acid plasticizers. Agents. These flexibility-imparting agents may be used alone or in combination of two or more.

Examples of the polyhydric alcohol plasticizer include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1, 4-butanediol, pentanediol, hexanediol, neopentyl glycol, polyethylene glycol, polypropylene glycol, poly (ethylene oxide-propylene oxide) block copolymer or random copolymer, polytetramethylene glycol, bisphenol, glycerin, diglycerin, Multivalent such as polyglycerol, erythritol, xylitol, mannitol, sorbitol, trimethylene propanol, pentaerythritol, dipentaerythritol Lucol: Triethylene glycol di- (2-ethylbutyrate), triethylene glycol di- (2-ethylhexoate), dibutylmethylene bis-thioglycolate, glycerol monoacetate, glycerol diacetate, glycerol triacetate, glycerol tri Butyrate, glycerin tripropionate, glycerin diacetomonocaprate, glycerin monoacetomonolaurate, glycerin diacetomonooleate, glycerin monoricinoleate triacetate, glycerin monoacetomonomontanate, diglycerin tetraacetate, polyglycerin monolaurate acetate Polyhydric alcohol derivatives such as ethylene oxide addition polymers, alkylene oxide addition polymers such as propylene oxide addition polymers, etc.
A commercially available polyhydric alcohol plasticizer may be used as the polyhydric alcohol plasticizer. Examples of commercially available polyhydric alcohol plasticizers include “Riquemar PL-019” (trade name, manufactured by Riken Vitamin Co., Ltd.) and “Riquemar PL-710” (trade name, manufactured by Riken Vitamin Co., Ltd.). Can be mentioned.

Examples of the polybasic acid ester plasticizer include adipic acid esters such as di-n-butyl adipate, diisobutyl adipate, di- (2-ethylhexyl) adipate, diisooctyl adipate, diisodecyl adipate, octyldecyl adipate, and dicapryl adipate. Dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, diamyl phthalate, dihexyl phthalate, butyl octyl phthalate, butyl isodecyl phthalate, butyl lauryl phthalate, di- (2-ethylhexyl) phthalate, di-n-octyl phthalate, di 2-octyl phthalate, dilauryl phthalate, diheptyl phthalate, diisooctyl phthalate, octyl decyl phthalate, n-octyl-n-de Phthalic acid esters such as ruphthalate, diisodecyl phthalate, ditridecyl phthalate, ethylhexyl decyl phthalate, dicyclohexyl phthalate; maleic acid esters such as di-n-butyl maleate, dimethyl maleate, diethyl maleate, di- (2-ethylhexyl) maleate, dinonyl maleate Fumarate esters such as dibutyl fumarate and di- (2-ethylhexyl) fumarate; tri- (2-ethylhexyl) trimellitate, triisodecyl trimellitate, n-octyl, n-decyl trimellitate, triisooctyltri And trimellitic acid esters such as melitrate and diisooctyl monoisodecyl trimellitate.
As the polybasic acid ester plasticizer, a commercially available polybasic acid ester plasticizer may be used. As the polybasic acid ester plasticizer, for example, “MXA” (trade name, manufactured by Daihachi Chemical Industry Co., Ltd.), “BXA” (trade name, manufactured by Daihachi Chemical Industry Co., Ltd.), “DAIFATTY-101” "(Trade name, manufactured by Daihachi Chemical Industry Co., Ltd.)," PX-844 "(trade name, manufactured by Adeka Co., Ltd.).

  Examples of the polyester plasticizer include dicarboxylic acids such as adipic acid, sebacic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, propylene glycol, 1,3-butanediol, 1,4-butanediol, Examples thereof include polyesters that are reactive products with diols such as 1,6-hexanediol, ethylene glycol, and diethylene glycol; and polyesters that are reaction products of hydroxycarboxylic acids such as polycaprolactone.

  Examples of the phosphate ester plasticizer include triethyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, trioctyl phosphate, triphenyl phosphate, diphenyl-2-ethylhexyl phosphate, trixylyl phosphate, and phosphoric acid. Examples include tricresyl.

  Examples of the epoxy plasticizer include butyl epoxy stearate, epoxy monoester, octyl epoxy stearate, epoxidized butyl oleate, and di- (2-ethylhexyl) -4,5-epoxycyclohexane-1,2-carboxylate. Epoxidized semi-drying oil, epoxidized triglyceride, epoxy butyl stearate, epoxy octyl stearate, epoxy decyl stearate, epoxidized soybean oil, epoxidized linseed oil, methyl epoxy hydrostearate, glyceryl tri (epoxy acetoxy systemate) And isooctyl epoxy stearate.

  Examples of the fatty acid plasticizer include methyl oleate, butyl oleate, methoxy ethyl oleate, glyceryl mono oleate, diethylene glycol mono oleate, methyl acetyl ricinoleate, butyl acetyl ricinolate, glyceryl mono ricinoleate, diethylene glycol mono ricinoleate, glyceryl tri ( Acetylricinolate), alkylacetylricinolate, n-butyl stearate, glyceryl monostearate, diethylene glycol distearate, diethylene glycol monolaurate.

  Examples of the sulfonic acid plasticizer include benzenesulfone butyramide, o-toluenesulfonamide, p-toluenesulfonamide, N-ethyl-p-toluenesulfonamide, o-tolueneethylsulfonamide, p-tolueneethylsulfonamide. , N-cyclohexyl-p-toluenesulfonamide.

  As a mixing method of the thermoplastic resin composition of the present invention, a known mixing method can be used. For example, melt blending with a desktop small kneading and molding machine, a batch kneader, a single-screw or multi-screw extruder, etc. A method is mentioned.

  The molded article of the present invention is obtained by molding the thermoplastic resin composition of the present invention. A known molding method can be used as the molding method, and examples thereof include extrusion molding, injection molding, press molding, inflation molding, and calendar molding.

  Since the molded article of the present invention is excellent in flexibility, durability and heat resistance, it can be used as a resin material for various applications. In particular, by forming into a film or sheet, it can be suitably used for industrial and food packaging materials.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.
In the examples, “parts” and “%” indicate “parts by mass” and “% by mass”, respectively.

(1) Molecular Weight The mass average molecular weight of the (meth) acrylate polymer (B) was measured using gel permeation chromatography (model name “GPC150C”, manufactured by Waters). Polymethyl methacrylate was used as the standard and chloroform was used as the mobile phase.

(2) Blended state The thermoplastic resin composition is melt-kneaded at a barrel temperature of 200 ° C. using a desktop small kneader (model name “CS-183”, manufactured by Custom Scientific Instruments), and a thermoplastic resin is obtained. A mass of the composition was obtained. The obtained lump was visually observed, and the blended state of the thermoplastic resin composition was determined by the following index.
○: The raw material was not separated, and an integrated lump was obtained.
X: Some raw materials remained separated, and an integrated lump was not obtained.

(3) Formability The thermoplastic resin composition was heated at a plate temperature of 180 ° C. and a gauge pressure of 30 kg / cm ² using a heating press panel (manufactured by Oji Machinery Co., Ltd., maximum load 37 t, maximum operating pressure 210 kg / cm ² ). The film was molded under the above conditions to obtain a film molded body (thickness: 100 μm). The obtained film was visually observed, and the moldability of the thermoplastic resin composition was determined by the following index.
(Double-circle): The film was transparent and the defect was not confirmed.
○: The film was transparent, and undulation was confirmed, but it was not problematic in use.
X: The film was opaque, and defects such as waving, shrinking, bending, bending, cracking, and cracking were confirmed.

(4) Flexibility The thermoplastic resin composition is molded using a desktop compact kneading and molding machine (model name “CS-183”, manufactured by Custom Scientific Instruments) under the condition of a barrel temperature of 200 ° C., and a molded body ( A short side 10 mm, a long side 20 mm, and a thickness 2 mm) were obtained. The durometer D hardness of the obtained molded body was measured in accordance with JIS K7215, and the flexibility of the molded body was determined by the following index.
A: The durometer D hardness of the molded body was less than 70.
(Circle): Durometer D hardness of the molded object was 70 or more and 80 or less.
X: The durometer D hardness of the molded body exceeded 80.

(5) Durability The thermoplastic resin composition was heated at a plate temperature of 180 ° C. and a gauge pressure of 30 kg / cm ² using a heating press panel (manufactured by Oji Machinery Co., Ltd., maximum load 37 t, maximum operating pressure 210 kg / cm ² ). The film was molded under these conditions to obtain a film molded body (3 cm on a side, 50 μm thick). After the obtained film was held in an oven at 80 ° C. for 10 days, the film was visually observed, and the durability of the molded product was determined by the following index.
○: Whitening was not observed and the sample was transparent, and no precipitate was confirmed.
(Triangle | delta): Although whitening was seen, the deposit was not confirmed.
X: Whitening was seen and the deposit was confirmed.

(6) Heat resistance The thermoplastic resin composition was heated at a plate temperature of 180 ° C. and a gauge pressure of 30 kg / cm ² using a heating press panel (manufactured by Oji Machinery Co., Ltd., maximum load 37 t, maximum operating pressure 210 kg / cm ² ). The film was molded under the above conditions to obtain a film molded body (width 4 mm, thickness 100 μm). Using the thermomechanical analyzer (model name “TMA / SS6100”, manufactured by Seiko Instruments Inc.), the obtained film was heated from 25 ° C. under the conditions of tensile mode, distance between chucks of 10 mm, and tensile stress of 2 mN. While increasing the temperature at 5 ° C./min, the temperature at which the rate of change in the distance between chucks reached 3% was measured, and the heat resistance of the molded product was determined by the following index.
A: The temperature at which the rate of change in the distance between chucks reached 3% exceeded 70 ° C.
A: The temperature at which the change rate of the distance between chucks reached 3% was 60 ° C. or higher and 70 ° C. or lower.
Δ: The temperature at which the rate of change in the distance between chucks reached 3% was 50 ° C. or higher and lower than 60 ° C.
X: The temperature at which the rate of change in the distance between chucks reached 3% was less than 50 ° C.

[Production Example 1]
A mixture composed of 100 parts of methyl acrylate and 0.3 part of azobisisobutyronitrile was charged into a reaction vessel, heated at 60 ° C. for 4 hours, and then heated at 80 ° C. for 2 hours to obtain a (meth) acrylate polymer. (B1) was obtained.
The weight average molecular weight of the (meth) acrylate polymer (B1) was 500,000.
The glass transition temperature of polymethyl acrylate is 10 ° C. according to the polymer handbook (4th edition, published by John Wiley & Sons Inc.).

[Examples 1 to 3]
Using the (meth) acrylate polymer (B1) obtained in Production Example 1, blended with the composition shown in Table 1, and using a tabletop compact kneader (model name “CS-183”, manufactured by Custom Scientific Instruments). Then, melt kneading was performed under a barrel temperature condition of 200 ° C. to obtain a thermoplastic resin composition. Each evaluation of a thermoplastic resin composition and a molded object was performed using the obtained thermoplastic resin composition.
In addition, poly DL-lactic acid “Lacia H-280” (trade name, manufactured by Mitsui Chemicals, Inc., mass average molecular weight 170,000) was used as the hydroxycarboxylic acid polymer (A).

[Comparative Examples 1-4]
Poly DL-lactic acid “Lacia H-280” (trade name, manufactured by Mitsui Chemicals, Inc., mass average molecular weight 170,000) as the hydroxycarboxylic acid polymer (A), and Aldrich as the (meth) acrylate polymer (B2) As the methyl acrylate polymer (mass average molecular weight 50,000) manufactured by the company, the methyl acrylate polymer (mass average molecular weight 10000) manufactured by Soken Chemical Industry Co., Ltd. was used as the (meth) acrylate polymer (B3). It mix | blended with the composition shown to the above and obtained the thermoplastic resin composition. Each evaluation of a thermoplastic resin composition and a molded object was performed using the obtained thermoplastic resin composition.

  Table 1 shows the results of each evaluation using the thermoplastic resin compositions obtained in Examples 1 to 3 and Comparative Examples 1 to 4.

In Examples 1 to 3 using the (meth) acrylate polymer (B1) of the present invention, the thermoplastic resin composition is excellent in blending state and moldability, and the molded body is excellent in flexibility, durability and heat resistance. It was. On the other hand, in Comparative Examples 1 and 3 using (meth) acrylate polymers (B2) and (B3) whose mass average molecular weight is outside the range of the present invention, the molded product is inferior in the blended state of the thermoplastic resin composition. Could not get. In Comparative Examples 2 and 4 in which the composition of the thermoplastic resin composition was changed, the blended state and moldability of the thermoplastic resin composition were improved, but the flexibility of the molded article was poor. In addition, since the evaluation of durability and heat resistance in this example is a criterion for a molded article having flexibility, it was not applicable to a molded article having poor flexibility, and the measurement was abandoned.

  The thermoplastic resin composition of the present invention is excellent in moldability and is excellent in flexibility, durability and heat resistance of the resulting molded product, and therefore can be used as a resin material for various applications. In particular, by forming into a film or sheet, it can be suitably used for industrial and food packaging materials.

Claims (2)

Hydroxycarboxylic acid polymer (A) and obtained methyl acrylated preparative (b1) by polymerizing a monomer component (b) containing over 90 wt%, the glass transition temperature is at 60 ° C. or less, the weight average A thermoplastic resin composition comprising an acrylate polymer (B) having a molecular weight of 300,000 to 1,000,000.   A molded article obtained by molding the thermoplastic resin composition according to claim 1.