JP2009173735A - Method for producing thermoplastic resin composition, thermoplastic resin composition and molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polylactic acid-containing thermoplastic resin composition having an excellent balance of hydrolysis resistance, heat resistance and impact resistance.
A method for producing a thermoplastic resin composition (E) according to the present invention comprises:
A resin (C) having a melt mass flow rate (MFR: 190 ° C., 2.16 kg load) of 3 to 30 g / 10 minutes of polylactic acid (A) 40 to 90% by weight and modified polyphenylene ether (B) 60 to 10% by weight ) 100 parts by weight,
The polylactic acid crosslinking agent (D) is mixed with 0.1 to 8 parts by weight.
[Selection figure] None

Description

  The present invention relates to a method for producing a thermoplastic resin composition containing polylactic acid, the composition, and a molded article formed by molding the composition. More specifically, the present invention relates to a method for producing a polylactic acid-containing thermoplastic resin composition having an excellent balance of hydrolysis resistance, heat resistance and impact resistance.

  In general, various molded products made of thermoplastic resin are synthesized using raw fossil resources such as crude oil as raw materials. From the viewpoint of controlling the use of embedded fossil resources, recently, they have been synthesized using plant-derived raw materials. There is a strong demand for the use of thermoplastic resins.

  Thermoplastic resins synthesized using plant-derived raw materials absorb carbon dioxide during the growth process of plants, so that the concentration of carbon dioxide in the environment does not increase even when incinerated at the time of disposal, for example. Also have. For this reason, thermoplastic resins synthesized using plant-derived raw materials can reduce the amount of carbon dioxide generated in addition to reducing the use of buried fossil resources, thereby solving environmental problems such as prevention of global warming. Expected to get.

Polylactic acid is known as a thermoplastic resin synthesized using such plant-derived raw materials. Since polylactic acid has a high melting point, can be melt-molded, and has biodegradability, it is particularly expected as a thermoplastic resin synthesized using plant-derived raw materials.
However, since polylactic acid has insufficient heat resistance, further improvement is desired. Polylactic acid is a resin having excellent impact resistance, but the impact resistance may be significantly impaired by mixing with other resins. Furthermore, there is a problem in hydrolysis resistance such that the strength deteriorates due to hydrolysis in a wet environment. Thus, since polylactic acid is insufficient in heat resistance, impact resistance, and hydrolysis resistance, the fields where it can be practically used are limited.

 In order to improve heat resistance, for example, Patent Document 1 discloses a biodegradable resin composition containing polylactic acid and an amorphous resin having a glass transition temperature higher than that of the polylactic acid. In Patent Document 1, polystyrene, ABS resin, polycarbonate, and the like are used in the examples as the amorphous resin, but modified polyphenylene ether is also exemplified as a usable resin. According to Patent Document 1, it is described that a molded product maintaining strength and heat resistance can be obtained by blending an amorphous resin having a high glass transition temperature with polylactic acid.

 As described in Patent Document 1, the heat resistance of the polylactic acid-containing resin composition is improved to some extent by adding an amorphous resin having a high glass transition temperature. However, in the development of various uses, improvement of hydrolysis resistance is desired.

 In Patent Document 2, the hydrolysis resistance of the biodegradable resin composition is improved to some extent by adding an epoxy compound having at least two epoxy groups in the molecule and a molecular weight of 300 or more. However, the impact resistance and heat resistance have not been studied.

  Patent Document 3 discloses a lactic acid resin composition using polylactic acid in which at least a part of the carboxyl group ends are blocked with a carbodiimide compound, and Patent Document 4 discloses an aromatic polyester resin and a polylactic acid resin. The point that the thermoplastic resin which mix | blends contains a carbodiimide compound as a compatibilizing agent is disclosed. However, they have insufficient impact resistance improvement and are not sufficiently excellent in the balance between hydrolysis resistance, heat resistance and impact resistance.

JP 2005-60637 A Japanese Patent Application Laid-Open No. 2004-10893 JP 2007-154002 A JP 2007-224290 A

 This invention is made | formed in view of such an actual condition, and it aims at providing the manufacturing method of the polylactic acid containing thermoplastic resin composition excellent in the balance of hydrolysis resistance, heat resistance, and impact resistance.

The present invention that solves this problem includes the following matters as a gist.
(1) Melt mass flow rate (MFR: 190 ° C., 2.16 kg load) consists of 40 to 90% by weight of polylactic acid (A) of 3 to 30 g / 10 minutes and 60 to 10% by weight of modified polyphenylene ether (B). 100 parts by weight of resin (C);
A method for producing a thermoplastic resin composition (E), comprising mixing 0.1 to 8 parts by weight of a polylactic acid crosslinking agent (D).
(2) The modified polyphenylene ether (B) is
Styrene-modified polyphenylene ether (Bs) having a melt mass flow rate (MFR: 250 ° C., 10 kg load) of 1 to 10 g / 10 min and / or a melt mass flow rate (MFR: 250 ° C., 10 kg load) of 1 to 30 g / 10 min It is an olefin-modified polyphenylene ether (Bo),
The manufacturing method of the thermoplastic resin composition as described in said (1).
(3) The polylactic acid crosslinking agent (D) is a carbodiimide compound.
The manufacturing method of the thermoplastic resin composition as described in said (1) or (2).
(4) Further, 5 to 100 parts by weight of a fibrous filler having an aspect ratio of 5 or more is mixed.
The manufacturing method of the thermoplastic resin composition in any one of said (1)-(3).
(5) A thermoplastic resin composition obtained by the method for producing a thermoplastic resin composition according to any one of (1) to (4).
(6) A molded product obtained by molding the thermoplastic resin composition according to (5).

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the polylactic acid containing thermoplastic resin composition excellent in the balance of hydrolysis resistance, heat resistance, and impact resistance is provided.

  Hereinafter, the manufacturing method of the thermoplastic resin composition of the present invention, the composition, and a molded product obtained by molding the composition will be described.

Components of Thermoplastic Resin Composition The method for producing the thermoplastic resin composition (E) of the present invention comprises a polylactic acid crosslinking agent (D) and a resin (C) comprising polylactic acid (A) and modified polyphenylene ether (B). It is characterized by mixing.

The blending amount of the polylactic acid (A) in the resin (C) is 40 to 90% by weight, preferably 40 to 80% by weight, more preferably 40 to 70% by weight, particularly preferably 40 to 60% by weight. The blending amount of the polyphenylene ether (B) is 60 to 10% by weight, preferably 60 to 20% by weight, more preferably 60 to 30% by weight, and particularly preferably 60 to 40% by weight. If the amount of the modified polyphenylene ether is too small, the heat resistance, impact resistance and hydrolyzability may be inferior. On the other hand, if the amount of the modified polyphenylene ether is too large, the advantages of using polylactic acid (such as the effect of reducing the environmental load) are reduced, and the processability is reduced (the processing temperature is increased and the fluidity during molding is reduced). May be difficult to mold) and the rigidity may deteriorate.
The compounding quantity of polylactic acid crosslinking agent (D) is 0.1-8 weight part with respect to 100 weight part of said resin (C), Preferably it is 0.3-5 weight part, More preferably, it is 0.5-4 weight. Parts, particularly preferably 1 to 3 parts by weight. If the amount of the polylactic acid crosslinking agent is too small, the heat resistance, impact resistance, and hydrolyzability may be inferior. On the other hand, when the compounding amount of the polylactic acid crosslinking agent is too large, the processability may be lowered (the processing temperature becomes higher, the fluidity at the time of molding is lowered and it becomes difficult to mold), or the rigidity may be deteriorated.
First, the polylactic acid (A), the modified polyphenylene ether (B) and the polylactic acid crosslinking agent (D) used in the present invention will be described more specifically.

Polylactic acid (A)
Examples of the polylactic acid (A) used in the present invention include a lactic acid homopolymer which is a homopolymer of lactic acid, a lactic acid copolymer obtained by copolymerizing lactic acid and another compound, and a blend polymer obtained by blending these. It is done.

Polylactic acid has processability to such an extent that it can be injection-molded, and its melt mass flow rate (MFR: 190 ° C., 2.16 kg load) is 3 to 30 g / 10 minutes, preferably 5 to 20 g / 10 minutes. is there. If the MFR of polylactic acid is too low, processability may be reduced and miscibility with modified polyphenylene ether may be reduced. On the other hand, when the MFR of polylactic acid is too high, the hydrolysis resistance, heat resistance, and impact resistance of the resulting resin composition are lowered. The configuration weight ratio W _{L /} W _D of the L- lactic acid unit and D- lactic acid unit in the polylactic acid is not particularly limited, from the viewpoint that it is possible to increase the melting point, L- lactic acid, D- lactic acid It is preferable that any one of these units is contained in an amount of 75% by weight or more, and more preferably 90% by weight or more. In the present invention, those containing L-lactic acid units are preferably 75% by weight or more, particularly 90% by weight or more.

  The lactic acid copolymer is obtained by copolymerizing a lactic acid monomer or another component copolymerizable with lactide that can be synthesized from the lactic acid monomer together with the lactic acid monomer. Examples of such other copolymerizable components include compounds having two or more functional groups capable of forming ester bonds, such as dicarboxylic acids, polyhydric alcohols, hydroxycarboxylic acids, lactones, and the like. Examples include various polyesters and various polyethers as constituent components.

  The production method of polylactic acid is not particularly limited and can be produced by a conventionally known method. For example, it can be produced by the following method.

  First, a concentrated and refined product of lactic acid is produced from sugarcane, corn, and potatoes as raw materials. Specifically, a crude sugar solution is collected by squeezing sugarcane or the like as a raw material, and the obtained crude sugar solution is concentrated. And fermented microbial cells are put into the concentrated crude sugar solution and fermented to produce crude lactic acid. Next, the fermented cells are removed from the crude lactic acid solution and concentrated. Finally, the concentrated solution obtained is concentrated again by evaporation purification to obtain a concentrated and purified product (liquid) of lactic acid.

Next, the concentrated and purified product of lactic acid obtained above is polymerized to obtain polylactic acid.
Specifically, first, the lactic acid concentrate / refined product is further concentrated, and then an oligomer is produced by a dehydration condensation reaction. Next, the obtained oligomer is reacted to obtain a crude lactide, and the obtained crude lactide is melt-crystallized to purify the lactide. And polylactic acid can be obtained by ring-opening-polymerizing the obtained lactide.

  When polylactic acid is used as a lactic acid copolymer, other oligomers that can be copolymerized with the lactic acid monomer when generating an oligomer from a lactic acid monomer, when generating a crude lactide from an oligomer, or when ring-opening polymerization of a lactide are performed. What is necessary is just to add an ingredient suitably.

Modified polyphenylene ether (B)
The modified polyphenylene ether (B) is a general term for a synthetic resin polymer alloy belonging to a thermoplastic resin mainly composed of polyphenylene ether (PPE) having an aromatic polyether structure. In the present invention, styrene-modified polyphenylene ether (Bs) and / or olefin-modified polyphenylene ether (Bo) are particularly preferably used.
The modified polyphenylene ether (B) used in the present invention has processability to such an extent that it can be injection-molded, and its melt mass flow rate (MFR: 250 ° C., 10 kg load) is 1 in the case of styrene-modified polyphenylene ether (Bs). -10 g / 10 min, preferably 3-7 g / 10 min. In the case of olefin-modified polyphenylene ether (Bo), it is 1 to 30 g / 10 minutes, preferably 15 to 27 g / 10 minutes.

In the case of styrene-modified polyphenylene ether, if the MFR is too low, the processability may be reduced, and the miscibility with polylactic acid may be reduced. On the other hand, when the MFR of the styrene-modified polyphenylene ether is too high, the heat resistance and hydrolysis resistance of the resulting resin composition are lowered.
In the case of an olefin-modified polyphenylene ether, if the MFR is too low, processability and miscibility with polylactic acid may be reduced. On the other hand, if the MFR of the olefin-modified polyphenylene ether is too high, the heat resistance is greatly lowered, and it becomes difficult to balance the hydrolysis resistance.

 The modified polyphenylene ether is not particularly limited, and commercially available products can also be used. Preferred modified polyphenylene ethers include a polyphenylene ether polymer represented by the following chemical formula 1 and a graft copolymer of a styrene monomer. Polyphenylene ether, a block copolymer obtained by oxidative polymerization of a phenolic monomer represented by the following chemical formula 2 and a styrene monomer in the presence of a catalyst such as an amine complex of copper (II), and polystyrene. Alternatively, styrene-modified polyphenylene ether, olefin-modified polyphenylene ether, and the like obtained as a result of blending with polyolefin or the like are exemplified, and olefin-modified polyphenylene ether is particularly preferable.

 The modified polyphenylene ether may be used alone or in combination. When the styrene-modified polyphenylene ether and the olefin-modified polyphenylene ether are used in combination, the olefin-modified polyphenylene ether is preferably 50 to 200 parts by weight, more preferably 60 to 150 parts by weight with respect to 100 parts by weight of the styrene-modified polyphenylene ether. Parts, particularly preferably 80 to 120 parts by weight.

（Ｒ¹ 、Ｒ² は炭素数が１〜４のアルキル基又はハロゲン原子を示し、ｎは重合度を示す。）

(R ¹ and R ² represent an alkyl group having 1 to 4 carbon atoms or a halogen atom, and n represents the degree of polymerization.)

 Examples of the polyphenylene ether represented by the above chemical formula 1 include poly (2,6-dimethylphenylene-1,4-ether), poly (2,6-diethylphenylene-1,4-ether), poly (2, 6-dichlorophenylene-1,4-ether), poly (2,6-dibromophenylene-1,4-ether), poly (2-methyl-6-ethylphenylene-1,4-ether), poly (2- Chloro-6-methylphenylene-1,4-ether), poly (2-methyl-6-isopropylphenylene-1,4-ether), poly (2,6-di-n-propylphenylene-1,4-ether) ), Poly (2-bromo-6-methylphenylene-1,4-ether), poly (2-chloro-6-bromophenylene-1,4-ether), poly (2-chloro-6-ether) Rufeniren 1,4 ether) and the like, which may be used in combination be used alone, also the degree of polymerization n is suitably used those 10 to 5000.

（Ｒ³ 、Ｒ⁴ は炭素数が１〜４のアルキル基又はハロゲン原子を示す。）

(R ³ and R ⁴ represent an alkyl group having 1 to 4 carbon atoms or a halogen atom.)

 Examples of the phenolic monomer represented by Chemical Formula 2 include 2,6-dimethylphenol, 2,6-diethylphenol, 2,6-dichlorophenol, 2,6-dibromophenol, and 2-methyl-6-ethyl. Phenol, 2-chloro-6-methylphenol, 2-methyl-6-isopropylphenol, 2,6-di-n-propylphenol, 2-bromo-6-methylphenol, 2-chloro-6-bromophenol, 2 -Chloro-6-ethylphenol etc. are mentioned, These may be used independently or may be used together.

 Examples of the styrene monomer that is graft copolymerized with polyphenylene ether or block copolymerized with a phenol monomer include styrene; α-methylstyrene, 2,4-dimethylstyrene, p-methylstyrene, ethylstyrene, pt -Alkylated styrene such as butylstyrene; halogenated styrene such as monochlorostyrene and dichlorostyrene.

Styrene-modified polyphenylene ether (Bs)
The styrene-modified polyphenylene ether (Bs) is preferably a styrene-modified polyphenylene ether having a phenylene ether component of 40 to 85% by weight and a styrene component of 60 to 15% by weight, and a phenylene ether component of 40 to 80% by weight and A styrene-modified polyphenylene ether having a styrene component of 60 to 20% by weight is more preferable, and a styrene-modified polyphenylene ether having a phenylene ether component of 50 to 75% by weight and a styrene component of 50 to 25% by weight is particularly preferable.

 If the amount of the phenylene ether component in the modified polyphenylene ether such as styrene-modified polyphenylene ether is small, the heat resistance of the resulting resin composition may be lowered. On the other hand, when there are many phenylene ether components, there exists a possibility that a moldability may fall.

Olefin-modified polyphenylene ether (Bo)
Polyolefins that are melt-kneaded and blended with polyphenylene ether include, for example, high-density polyethylene, ultra-high molecular weight high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene with a density of less than 0.90, and isotactic. Copolymers of two or more compounds selected from polypropylene, ethylene, propylene, other α-olefins, unsaturated carboxylic acids or derivatives thereof, such as ethylene / butene-1 copolymer elastomers, ethylene- (meta ) Acrylic acid copolymer, methylene- (meth) acrylic acid ester copolymer, propylene / ethylene (random, block) copolymer resin, propylene / 1-hexene copolymer, propylene / 4-methyl-1-pentene Copolymer and poly (4-methyl-1-pente) ), It can be exemplified Poriputen -1 like, which can be used in combination of two or more not only one kind.

 The olefin-modified polyphenylene ether (Bo) is preferably an olefin-modified polyphenylene ether having a phenylene ether component of 50 to 97% by weight and an olefin component of 50 to 3% by weight, and a phenylene ether component of 55 to 90% by weight and An olefin-modified polyphenylene ether having an olefin component of 45 to 10% by weight is more preferable, and an olefin-modified polyphenylene ether having a phenylene ether component of 65 to 90% by weight and an olefin component of 35 to 10% by weight is particularly preferable.

Polylactic acid crosslinking agent (D)
The polylactic acid crosslinking agent (D) refers to a compound that reacts with a carboxyl group or a hydroxyl group contained in polylactic acid to give a crosslinked structure.
Examples of the polylactic acid crosslinking agent (D) include carbodiimide compounds, polyisocyanate compounds, polyisocyanurate compounds, polyepoxide compounds, oxazoline compounds, and oxazine compounds. Among these, carbodiimide compounds are preferably used. These can be used alone or in combination of two or more.

 Examples of the carbodiimide compound include 4,4'-dicyclohexylmethane carbodiimide, tetramethylxylylene carbodiimide, N, N-dimethylphenyl carbodiimide, N, N'-di-2,6-diisopropylphenyl carbodiimide, and the like.

 Examples of polyisocyanate compounds include phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, dimethyldiphenylmethane diisocyanate, triphenylmethane triisocyanate, naphthalene diisocyanate, polymethylene polyphenyl polyisocyanate tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate. Examples include methylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, hydrogenated xylene diisocyanate, and 1,4-diisocyanate cyclohexane.

 Examples of the polyisocyanurate compound include the isocyanurate forms of the above compounds.

 Examples of the polyepoxide compound include a homopolymer of glycidyl acrylate or glycidyl methacrylate, or one or more (meth) acrylic acid esters selected from methyl methacrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, and butyl methacrylate. Copolymers with monomers, epoxidized oils and fats (eg, epoxidized soybean oil, epoxidized linseed oil, etc.), epoxidized fatty acid esters (eg, epoxidized butyl stearate, epoxidized octyl stearate, epoxidized stearic acid) Ethyl hexyl), epoxidized aliphatic polyethers (eg, sorbitol polyglycidyl ether, novolac glycidyl ether, pentaerythritol polyglycy) Ether, etc.), and the like.

 Examples of the oxazoline compound include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2- Examples include isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like.

  Examples of the oxazine compound include 2,2′-bis (2-oxazine), 4-furan-2-ylmethylene-2-phenyl-4H-oxazyl-5-one, 1,4-bis (4,5-dihydro -2-oxazyl) benzene, 1,3-bis (4,5-dihydro-2-oxazyl) benzene, 2,3-bis (4-isopropenyl-2-oxazin-2-yl) butane, 2,2 ′ -Bis-4-benzyl-2-oxazine, 2,6-bis (isopropyl-2-oxazin-2-yl) pyridine, 2,2'-isopropylidenebis (4-tert-butyl-2-oxazine), 2 2,2'-isopropylidenebis (4-phenyl-2-oxazine), 2,2'-methylenebis (4-tert-butyl-2-oxazine), 2,2'-methylenebis (4-phenyl-2-oxa Down), and the like.

Other compounding agents In addition, the thermoplastic resin composition of the present invention includes a hybrid filler (of a filler obtained by high-speed stirring of two or more fillers in a dry manner within a range not impairing the effects of the present invention. ), Fillers such as calcium carbonate, glass fiber, wollastonite; anti-aging agents; lubricants; dusting agents; acid absorbents, etc. Preferably, it is a fibrous filler having an aspect ratio of 5 or more, more preferably a fibrous filler having an aspect ratio of 5 to 1000.

 These compounding agents such as fillers do not necessarily have to be blended, but the blending amount when blending is about 5 to 50 parts by weight with respect to a total of 100 parts by weight of polylactic acid and modified polyphenylene ether, and the aspect ratio is In the case of 5 or more fibrous fillers, the amount is 5 to 100 parts by weight.

  Moreover, you may mix | blend resin and rubber other than polylactic acid and modified polyphenylene ether in the thermoplastic resin composition of this invention in the range which does not impair the effect of this invention. Examples of such resins and rubbers include acrylic copolymer rubbers; polyethers such as polyethylene oxide and polyethylene glycol; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyacrylonitrile; styrene-acrylonitrile copolymers; It is done. These may not necessarily be blended, but the blending amount when blending is about 0.1 to 50 parts by weight with respect to 100 parts by weight of the total of polylactic acid and modified polyphenylene ether.

Method for Producing Thermoplastic Resin Composition The method for producing the thermoplastic resin composition (E) of the present invention comprises a resin (C) comprising the above polylactic acid (A) and a modified polyphenylene ether (B), and a polylactic acid crosslinked product. The agent (D) is kneaded or dispersed or dissolved in a solvent and then mixed. Moreover, you may add a fibrous filler as needed. Thereafter, the thermoplastic resin composition is obtained by removing the solvent. In the present invention, it is particularly preferable to produce by kneading.
The method of kneading the polylactic acid, the modified polyphenylene ether, the polylactic acid crosslinking agent, and the fibrous filler is not particularly limited, but the polylactic acid and the modified polyphenylene ether are pelletized in advance, and the polylactic acid and the modified form in the pellet state A method of kneading polyphenylene ether, polylactic acid crosslinking agent and fibrous filler with a kneader while applying shear at 170 to 300 ° C., particularly 180 to 250 ° C. is preferable. Although it does not specifically limit as a kneading machine, Batch type kneaders, such as a Brabender and a lab plast mill; Continuous type kneading machines, such as a single screw extruder and a twin screw extruder;

  When kneading using these kneaders, the above-mentioned polylactic acid and modified polyphenylene ether, polylactic acid crosslinking agent and fibrous filler are mixed in advance using a dry mixer such as a tumbler mixer. You may throw into a kneading machine in this state. Moreover, when using a continuous kneader, you may employ | adopt the method of supplying these continuously from a separate supply machine.

Molded Article The molded article of the present invention can be obtained by molding the thermoplastic resin composition of the present invention produced as described above. The method for molding the thermoplastic resin composition of the present invention is not particularly limited, and methods such as extrusion molding, injection molding, transfer molding, compression molding, calendar molding, blow molding, etc., are used in the same manner as ordinary thermoplastic resins. Can be mentioned. The molding temperature is preferably 150 to 300 ° C, more preferably 170 to 270 ° C.

  The molded product of the present invention thus obtained has an excellent balance of heat resistance, impact resistance and hydrolysis resistance, and has excellent molding stability. Therefore, it can be used for various applications, and specifically, it is suitably used as parts for electric / electronic devices, automobile parts, building material parts, various containers, trays, daily miscellaneous goods and the like.

The present invention will be specifically described below with reference to examples and comparative examples. [Part] and [%] in these examples are based on weight unless otherwise specified. However, the present invention is not limited only to these examples. Each characteristic was evaluated by the following method.

Melt mass flow rate (MFR)
The melt mass flow rate (MFR) of the resin component was measured according to JIS K 7210. Specifically, the polylactic acid was measured at a measurement temperature of 190 ° C. and a load of 2.16 kg, and the modified polyphenylene ether was measured at a measurement temperature of 250 ° C. and a load of 10 kg.

Izod impact strength (impact resistance)
The Izod impact strength (impact resistance) of the thermoplastic resin composition was measured according to JIS K 7110.
First, a molded article for evaluation for measuring Izod impact strength was manufactured. Specifically, the thermoplastic resin composition is press-molded at a pressure of 12.0 MPa and a temperature of 200 ° C. for 10 minutes using a metal frame having a thickness of 3 mm × 100 mm × 170 mm to obtain a plate-shaped molded product. It was.

   Next, a test piece having a width of 12.7 mm, a length of 64 mm, and a thickness of 3 mm was cut out from the obtained molded product, and a notch having a depth of 2.54 mm (A notch for No. 2 test piece) was formed at the center in the longitudinal direction. Attached to one side. Then, the test piece is fixed to the sample support base of the dedicated test machine specified in JIS K 7110, and one side having the notch is struck with a hammer. Impact strength was determined.

Deflection temperature under load (DTUL)
The deflection temperature under load (DTUL) was determined by cutting out a test piece having a width of 12.7 mm, a length of 170 mm, and a thickness of 3 mm from the molded product obtained above, and in accordance with JIS K 7191-2, the distance between fulcrums of 64 mm, 0 Measured at loads of .45 MPa and 1.80 MPa.

Flexural properties (bending strength, flexural modulus)
Bending properties (bending strength, flexural modulus) were determined by cutting a test piece having a width of 12.7 mm, a length of 80 mm, and a thickness of 3 mm from the molded product obtained above, and the distance between fulcrums according to JIS K 7171. The measurement was performed at 60 mm and a test speed of 2 mm / min.

Hydrolysis resistance (bending strength retention)
Hydrolysis resistance (bending strength retention) was obtained by cutting out a test piece having a width of 12.7 mm, a length of 80 mm, and a thickness of 3 mm from the molded product obtained above, and in an atmosphere of 80 ° C. × 90% RH for 100 hours. The test piece was taken out and the condition was adjusted by leaving it in an atmosphere of 23 ° C. × 50% RH for 24 hours. The bending strength was 60 mm between fulcrums and the test speed was 2 mm / min in accordance with JIS K 7171. Measured with Hydrolysis resistance (bending strength retention) was determined from the obtained bending strength and the following formula.
Hydrolysis resistance (Bending strength retention) = [(Bending strength after 80 ° C. × 90% RH) / (Initial bending strength)] × 100

Moreover, the component used for manufacture of the thermoplastic resin composition by an Example and a comparative example is shown below.
(A) Polylactic acid (manufactured by Toyota Motor Corporation, eco-plastic U'z, product number: S-17)
MFR (190 ° C., 2.16 kg load) = 11.2 g / 10 min

(B) Modified polyphenylene ether (Bs) Styrene-modified polyphenylene ether (manufactured by Asahi Kasei Chemicals Corporation, Zylon, product number: 500H)
MFR (250 ° C., 10 kg load) = 3.9 g / 10 min (Bo) Olefin-modified polyphenylene ether (SABIC Innovative Plastics Japan Co., Ltd., Noryl PPX, product number: 7115)
MFR (250 ° C. × 10 kg load): 26.8 g / 10 min)

(D) Polylactic acid crosslinking agent (D1) Carbodiimide (Nisshinbo Co., Ltd., Carbodilite, product number: LA-1)
(D2) Oxazoline copolymer (Nippon Shokubai Co., Ltd., Epocros, product number: PRS1005)
(D3) Epoxidized soybean oil (ADEKA Corporation, Adeka Sizer, product number: O-130S)

(F) Filler (F1) Glass fiber (manufactured by Owens Corning Japan, product number: CS JA FT689, φ10 μm, fiber length 3 mm)

Example 1
30 parts by weight of olefin-modified polyphenylene ether (Bo) and 1 part by weight of a polylactic acid crosslinking agent (D1) were dry-mixed by a tumbler mixer with respect to 70 parts by weight of polylactic acid (A) to obtain a pellet mixture. Then, the obtained pellet mixture is put into a feeder (pellet feeder) and supplied to a twin-screw extruder having a barrel inner diameter of 40 mm (BT-40 type manufactured by Plastic Engineering Laboratory Co., Ltd.), thereby forming a thermoplastic resin composition. Article pellets were made. Specifically, in the barrel, the mixture is heated and melted and kneaded at 200 to 220 ° C., and the melt and kneaded material is discharged in the form of strands from a die provided at the tip of the twin screw extruder, and the water tank The pellets were prepared by cooling and solidifying, and cutting the strand-like discharge with a pelletizer.

  Then, by using the obtained pellet-shaped thermoplastic resin composition, a molded article for evaluation was produced under the above-described conditions, and each evaluation of Izod impact strength, load deflection temperature, and bending characteristics was performed. The results are shown in Table 1.

Examples 2-9 and Comparative Examples 1-11
When adjusting the thermoplastic resin, the thermoplastic resin composition was adjusted and evaluated in the same manner as in Example 1 except that each component and its blending amount were changed as shown in Table 1 or Table 2. Went. The results are shown in Tables 1 and 2. However, the filler (F) is not melted during the heat melting and kneading.

  From Table 1 and Table 2, the following points can be confirmed.

Hydrolysis resistance As defined in the present invention, polylactic acid crosslinking agent (D) with respect to 100 parts by weight of resin (C) comprising 40 to 90% by weight of polylactic acid (A) and 60 to 10% by weight of polyphenylene ether (B) The thermoplastic resin compositions (Examples 1 to 9) in which 0.8 to 8 parts by weight are blended are compared to the thermoplastic resin compositions (Comparative Examples 1 to 11) that are not blended ratios defined in the present invention. Bending strength retention is high and hydrolysis resistance is excellent.

Heat Resistance and Impact Resistance Examples 1 to 9 have higher Izod impact strength and higher deflection temperature under load than Comparative Examples 1, 6 and 7. As a result, even when the thermoplastic resin not containing the modified polyphenylene ether and the polylactic acid crosslinking agent (Comparative Example 1) or the modified polyphenylene ether and the polylactic acid crosslinking agent is contained, the heat exceeding the range specified in the present invention is exceeded. Compared to the plastic resin (Comparative Examples 6 and 7), the thermoplastic resin defined in the present invention is superior in heat resistance and impact resistance.

Examples 5 and 8
The thermoplastic resin using olefin-modified polyphenylene ether as the modified polyphenylene ether (Example 5) is higher in bending strength retention and Izod impact strength than the thermoplastic resin composition using styrene-modified polyphenylene ether (Example 8). In addition, the deflection temperature under load is high, and it is excellent in hydrolysis resistance, heat resistance and impact resistance.

Examples 5-7
When the carbodiimide (D1), the oxazoline copolymer (D2), and the epoxidized soybean oil (D3) are respectively compared as the polylactic acid crosslinking agent, the bending strength retention rate and the deflection temperature under load are compared with the carbodiimide (D1) , An oxazoline copolymer (D2), and an epoxidized soybean oil (D3) in this order, and the hydrolysis resistance and heat resistance are also excellent in this order.

Claims (6)

Resin (C) having a melt mass flow rate (MFR: 190 ° C., 2.16 kg load) of 3 to 30 g / 10 minutes of polylactic acid (A) 40 to 90% by weight and modified polyphenylene ether (B) 60 to 10% by weight ) 100 parts by weight,
A method for producing a thermoplastic resin composition (E), comprising mixing 0.1 to 8 parts by weight of a polylactic acid crosslinking agent (D). The modified polyphenylene ether (B) is
Styrene-modified polyphenylene ether (Bs) having a melt mass flow rate (MFR: 250 ° C., 10 kg load) of 1 to 10 g / 10 min and / or a melt mass flow rate (MFR: 250 ° C., 10 kg load) of 1 to 30 g / 10 min It is an olefin-modified polyphenylene ether (Bo),
The manufacturing method of the thermoplastic resin composition of Claim 1. The polylactic acid crosslinking agent (D) is a carbodiimide compound.
The manufacturing method of the thermoplastic resin composition of Claim 1 or 2. Furthermore, 5 to 100 parts by weight of a fibrous filler having an aspect ratio of 5 or more is mixed,
The manufacturing method of the thermoplastic resin composition in any one of Claims 1-3.   The thermoplastic resin composition obtained by the manufacturing method of the thermoplastic resin composition in any one of Claims 1-4.   A molded article formed by molding the thermoplastic resin composition according to claim 5.