JP5014908B2 - Crystalline polylactic acid resin composition and molded article comprising the same - Google Patents

Description

  The present invention relates to a resin composition containing a polylactic acid resin having improved rigidity, impact resistance and moldability.

  Generally, as a raw material for molding, polypropylene resin (PP), acrylonitrile-butadiene-styrene resin (ABS), polyamide resin (PA6, PA66 etc.), polyester resin (PET, PBT etc.), polycarbonate resin (PC) etc. in use. Molded articles made from such resins are excellent in moldability and mechanical strength, but when discarded, they increase the amount of dust and are hardly decomposed in the natural environment. It remains in the ground semipermanently.

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

  Polylactic acid is improved in heat resistance by sufficiently progressing crystallization, and can be applied to a wide range of uses. However, polylactic acid alone is very slow in crystallization. Therefore, in order to improve the crystallization rate, various crystal nucleating agents have been added to polylactic acid and polylactic acid has been crosslinked.

  That is, as a technique for adding a crystal nucleating agent in order to promote crystallization of the polylactic acid, it is possible to add a carboxylic acid amide or ester having a specific molecular structure to Patent Document 1 and tricyclohexyl to Patent Document 2. Addition of trimesic acid amide, and Patent Document 3 disclose addition of ethylenebis-12-hydroxystearic acid amide.

  Further, as a technique for crosslinking polylactic acid in order to promote crystallization of polylactic acid, for example, Patent Document 4 includes blending a methacrylic acid ester compound, and Patent Document 5 includes an isocyanate compound. Each compounding is disclosed.

However, even when these crystal nucleating agents are added to polylactic acid or subjected to a crosslinking treatment, in order to obtain a practically sufficient crystallization rate, the mold temperature is set to 90 to 120. It had to be set to ° C.
For this reason, even when the crystallization of polylactic acid has progressed sufficiently, its rigidity is low at the time of extrusion and removal of the molded product, so it is necessary to set the molding cycle particularly long. The productivity of was inevitably low as compared with the case of conventional resin moldings. This has been a great hindrance to the widespread use of polylactic acid resins and molded articles thereof.
Further, since the mold temperature is set to 90 to 120 ° C., the temperature difference between the mold temperature and room temperature becomes large, and as a result, the shrinkage rate of the polylactic acid molded body has to be increased. Therefore, there are limits to the application of polylactic acid molded products to applications that require high dimensional accuracy, and it is not possible to use molds for existing resins, making it impossible to share molds. there were.

On the other hand, by using polylactic acid having high optical purity, crystallization can be promoted and heat resistance can be improved. For example, Patent Document 6 describes that among the total lactic acid components, 95% or more of the L isomer or 95% or more of the D isomer is preferable for improving heat resistance.
However, for example, in the injection molding of polylactic acid resin, polylactic acid having an L-form of 98 to 99% is usually used, and polylactic acid having an L-form content in this range, the above-described crystal nucleating agent, etc. Even in combination, the mold temperature had to be set to 90 to 120 ° C. when molding. That is, when a mold having a lower temperature is used, the polylactic acid crystallization rate is remarkably low, and a polylactic acid molded article having sufficient heat resistance cannot be obtained in a practically available injection molding cycle.

In recent years, products such as housings and housing parts for electronic and electrical equipment such as home appliances, personal computers, mobile phones, fixed telephones, office automation equipment, and housing parts have been increasingly required to be compact and thin. In Japan, thinning is progressing. Therefore, in addition to impact resistance, the molding material must have high rigidity to reduce the amount of deflection when a load is applied. In order to meet these demands, recently, a material in which glass fiber is blended with polyamide resin to impart high rigidity in addition to impact resistance has begun to be used.
However, using polylactic acid having biodegradability, it has not been possible to obtain a molded article excellent in rigidity and impact resistance in addition to the heat resistance and moldability as described above.
International Publication No. 2006/13797 Pamphlet JP 2006-328163 A JP 2003-226801 A JP 2003-128901 A Japanese Patent Laid-Open No. 2002-3709 JP 2007-051274 A

  Accordingly, an object of the present invention is a thin wall that can be used for applications such as home appliances such as air conditioners, TVs, and vacuum cleaners, portable information terminals such as mobile phones, personal computers, OA equipment, and parts and casings of electrical and electronic equipment. It is an object of the present invention to provide an environmentally friendly thermoplastic resin composition that has excellent rigidity, impact resistance, heat resistance, and moldability and can be used for a molded product.

  As a result of intensive studies to solve the above problems, the present inventors have used a polylactic acid resin having a low or high D-form content, a crystal nucleating agent and a glass fiber having a flat cross-sectional shape. A crystalline polylactic acid resin composition obtained by blending, or a polylactic acid resin having a low or high D-form content, an acrylate compound, and a peroxide are melt-kneaded and the cross-sectional shape is flat The present inventors have found that the above-mentioned problems can be solved by a crystalline polylactic acid resin composition obtained by blending glass fibers that are, and have reached the present invention.

That is, the gist of the present invention is as follows.
(1) 95 to 50 parts by mass of a polylactic acid resin (A) having a D-form content of 0.6% or less or 99.4% or more, and 0.03 to 5 parts by mass of a crystal nucleating agent (B) And a crystalline polylactic acid resin composition containing 20 to 40 parts by mass of a glass fiber (C) having a major axis / minor axis of 1.5 to 10 in a fiber cross section , wherein the crystal nucleating agent (B) is: N, N ′, N ″ -tricyclohexyltrimesic acid amide, N, N′-ethylenebis (12-hydroxystearic acid) amide, octanedicarboxylic acid dibenzoylhydrazide, and 5-sulfoisophthalic acid dimethyl metal salt 1 or more types of crystalline polylactic acid resin composition characterized by the above-mentioned .
(2) 95 to 50 parts by mass of a polylactic acid resin (A) having a D-form content of 0.6% or less or 99.4% or more, and a (meth) acrylic acid ester compound (D) 0.01 ~ 20 parts by mass and 0.02 to 20 parts by mass of peroxide (E) are melt-kneaded, and the crystal nucleating agent (B) is 0 with respect to 95 to 50 parts by mass of the polylactic acid resin (A). and .03～5 parts by weight a crystalline polylactic acid resin composition major axis / minor axis contains 20 to 40 parts by weight of glass fiber (C) 1.5 to 10 of the fiber cross section, crystal The nucleating agent (B) contains N, N ′, N ″ -tricyclohexyltrimesic acid amide, N, N′-ethylenebis (12-hydroxystearic acid) amide, octanedicarboxylic acid dibenzoylhydrazide, and 5-sulfoisophthalate. One or more selected from acid dimethyl metal salts Crystalline polylactic acid resin composition, characterized by.
(3) It contains 0.1 to 10 parts by mass of one or more reactive compounds (F) selected from a carbodiimide compound, an epoxy compound, and an oxazoline compound with respect to 100 parts by mass of the polylactic acid resin (A). The crystalline polylactic acid resin composition according to any one of (1) to (2).
(4) A molded product obtained by molding the crystalline polylactic acid resin composition according to any one of (1) to (3).
(5) A thin molded article obtained by injection molding the crystalline polylactic acid resin composition according to any one of (1) to (3).

  According to the present invention, even when molded as a thin molded product, it exhibits excellent rigidity, impact resistance, and heat resistance, and the molding cycle is set by setting the mold temperature at the time of injection molding lower than before. It is possible to provide an environmentally friendly thermoplastic resin composition that is shortened and has improved workability. Accordingly, it is suitable for use in home appliances such as air conditioners, televisions, and vacuum cleaners, portable information terminals such as mobile phones, personal computers, parts of electrical / electronic devices such as OA devices, and cases. Moreover, by using this resin composition for the above-mentioned products and the like, the range of use of polylactic acid, which is a low environmental load material, can be greatly expanded, and the industrial utility value is extremely high.

Hereinafter, the present invention will be described in detail.
The crystalline polylactic acid resin composition of the present invention comprises (1) a composition containing a polylactic acid resin (A), a crystal nucleating agent (B) and glass fibers (C), and (2) a polylactic acid resin (A). And (poly) acrylic acid ester compound (D) and peroxide (E) are melt-kneaded and contain a crystal nucleating agent (B) and glass fibers (C).

The polylactic acid resin (A) constituting the resin composition of the present invention is required to have a D-form content of 0.6% or less or a D-form content of 99.4% or more. . When a polylactic acid resin having a D-form content outside this range is used, if the mold temperature during molding is set lower than 90 to 120 ° C., a molded article having heat resistance cannot be obtained. The D-form content is preferably 0.3% or less, or preferably 99.7% or more.
In the present invention, when a polylactic acid resin (A) having a D-form content of 0.6% or less is used, a polylactic acid resin having a D-form content of less than 0.08% is obtained or produced. In the present invention, a polylactic acid resin having a D-form content of less than 0.08% can also be used. Similarly, when using a polylactic acid resin (A) having a D-form content of 99.4% or more, obtaining or producing a polylactic acid resin having a D-form content exceeding 99.92% In the present invention, a polylactic acid resin having a D-form content exceeding 99.92% can also be used.

  In the present invention, the D-form content of the polylactic acid resin (A) is a ratio (%) occupied by the D lactic acid unit in the total lactic acid units constituting the polylactic acid resin (A). Therefore, for example, in the case of a polylactic acid resin (A) having a D-form content of 0.6%, the polylactic acid resin (A) has a D-lactic acid unit occupying a ratio of 0.6%, and an L-lactic acid unit is included. The share is 99.4%.

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

As polylactic acid resin (A) used for this invention, polylactic acid resin of the range which D body content prescribes | regulates by this invention among various commercially available polylactic acid resins can be used.
Moreover, as a polylactic acid resin (A), among lactide which is a cyclic dimer of lactic acid, L-lactide having a sufficiently low D-form content or D-lactide having a sufficiently low L-form content is used as a raw material. The produced one can also be used.
Furthermore, in this invention, you may combine 2 or more types of polylactic acid resin as a polylactic acid resin (A). In this case, a polylactic acid resin having a D-form content outside the range specified in the present invention, for example, a polylactic acid resin having a D-form content exceeding 0.6% may be used in combination. And the polylactic acid resin (A) obtained by combining the polylactic acid resin satisfying the D-form content specified in the present invention, the D-form content may be 0.6% or less. Similarly, as a polylactic acid resin constituting the polylactic acid resin (A), a polylactic acid resin having a D-form content of less than 99.4% may be used in combination. In the polylactic acid resin (A) obtained in combination, The D body content should just be 99.4% or more.

  In the present invention, the polylactic acid resin (A) has a melt flow rate (for example, a value according to JIS standard K-7210 (test condition 4)) at 190 ° C. and a load of 21.2 N of 0.1 to 50 g / 10 minutes. It is preferably 0.2 to 20 g / 10 minutes, and more preferably 0.5 to 10 g / 10 minutes. When the melt flow rate exceeds 50 g / 10 min, the melt viscosity is too low, and the mechanical properties and heat resistance of the molded product may be inferior. On the other hand, when the melt flow rate is less than 0.1 g / 10 minutes, the load at the time of molding increases, and the operability may be lowered.

  The polylactic acid resin (A) is 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 (A) to a predetermined range, when the melt flow rate is too large, a small amount of chain extender, for example, a diisocyanate compound, a bisoxazoline compound, an epoxy compound, The method of increasing the molecular weight of resin using an acid anhydride etc. is mentioned. 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.

The resin composition of the present invention contains a crystal nucleating agent (B) for the purpose of promoting crystallization of the polylactic acid resin (A).
The compound used as the crystal nucleating agent is not particularly limited, and various compounds can be used. Examples of commercially available crystal nucleating agents include WX-1 manufactured by Kawaken Fine Chemical Co., Ltd., TF-1 manufactured by Shin Nippon Rika Co., Ltd., T-1287N manufactured by Adeka Co., Ltd., and master batch KX238B manufactured by Toyota. Specific compounds are selected from organic amide compounds, organic hydrazide compounds, carboxylic acid ester compounds, organic sulfonates, phthalocyanine compounds, melamine compounds, and organic phosphonates in terms of their crystallization promoting effects. It is preferable to use one or more selected from the above.

As the organic amide compound, compounds represented by the following general formulas (1) and (2) are preferable, and as the organic hydrazide compound, a compound represented by the general formula (3) is preferable.
R ^1- (CONH-R ² ) _a (1)
[Wherein, R ¹ represents a saturated or unsaturated aliphatic chain having 2 to 30 carbon atoms, a saturated or unsaturated aliphatic ring, or an aromatic ring. R ² represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms or a cycloalkenyl group, a phenyl group, a naphthyl group, an anthryl group, or the formula (a) Represents a group represented by any one of (d), and one or more hydrogen atoms may be substituted with a hydroxyl group. a represents an integer of 2 to 6. ]
[Wherein R ³ represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, a phenyl group, or a halogen atom. Represents an atom. l represents an integer of 1 to 5. ]
[Wherein, R ⁴ represents a linear or branched alkylene group having 1 to ⁴ carbon atoms. R ⁵ has the same meaning as R ³ described above. m represents an integer of 0 to 5. ]
[Wherein, R ⁶ has the same meaning as R ³ described above. n represents an integer of 1 to 5. ]
[Wherein, R ⁷ has the same meaning as R ⁴ above, and R ⁸ has the same meaning as R ³ above. o represents an integer of 0-6. ]
_{^{R 9 - (NHCO-R 10}} ) f (2)
[Wherein R ⁹ represents a saturated or unsaturated fatty chain having 2 to 30 carbon atoms, an unsaturated alicyclic ring, or an aromatic ring. R ¹⁰ has the same meaning as R ² described above. f represents an integer of 2-6. ]
_{^{R 11 - (CONHNHCO-R 12}} ) h (3)
[Wherein R ¹¹ represents a saturated or unsaturated fatty chain having 2 to 30 carbon atoms, an unsaturated alicyclic ring, or an aromatic ring. R ¹² has the same meaning as R ² described above. h represents an integer of 2 to 6. ]

  Specific compounds represented by the general formulas (1) to (3) include, for example, hexamethylene bis-9, 10-dihydroxy stearic acid bisamide, p-xylylene bis-9, 10 dihydroxy stearic 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, - diaminonaphthalene, ethylene bis-stearic acid amide, N, N'-ethylenebis (12-hydroxystearic acid) amide, octane dicarboxylic acid dibenzoyl hydrazide and the like.

  Of these, N, N ′, N ″ -tricyclohexyltrimesic acid amide, N, N′-ethylenebis (12-hydroxystearic acid) amide, octanedicarboxylic acid are preferred in view of dispersibility in the resin and heat resistance. Dibenzoyl hydrazide is preferable, and N, N ′, N ″ -tricyclohexyltrimesic acid amide and N, N′-ethylenebis (12-hydroxystearic acid) amide are particularly preferable.

  Various compounds can be used as the carboxylic acid ester-based compound, and for example, aliphatic bishydroxycarboxylic acid esters are preferable.

  As the organic sulfonate, various compounds such as sulfoisophthalate can be used, and among them, dimethyl metal salt of 5-sulfoisophthalic acid is preferable from the viewpoint of the effect of promoting crystallization. Furthermore, barium salt, calcium salt, strontium salt, potassium salt, rubidium salt, sodium salt and the like are preferable.

Although various compounds can be used as the phthalocyanine compound, it is preferable to use a transition metal complex, and among them, copper phthalocyanine is preferable from the viewpoint of the effect of promoting crystallization.
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 phosphonate, phenylphosphonate is preferable from the viewpoint of the crystallization promoting effect. Of these, zinc phenylphosphonate is particularly preferred.
As the crystal nucleating agent (B), these can be used alone or in combination of two or more. Note that various inorganic crystal nucleating agents may be used in combination with these organic crystal nucleating agents (B).

  In this invention, the compounding quantity of a crystal nucleating agent (B) needs to be 0.03-5 mass parts with respect to polylactic acid resin (A) 95-50 mass parts, and 0.1-4 mass Part. If the content of the crystal nucleating agent (B) is less than 0.03 parts by mass, the effect of blending is poor. On the other hand, when the content exceeds 5 parts by mass, the effect as a crystal nucleating agent is saturated, which is not only economically disadvantageous, but also increases the residue after biodegradation, which is not preferable in terms of environment.

The resin composition of this invention mix | blends glass fiber (C) for the purpose of improving the rigidity and impact resistance of a molded object. The ratio (major axis / minor axis of the fiber cross section) of the major axis of the fiber cross section and the minor axis of the fiber cross section in the glass fiber (C) needs to be 1.5 to 10, and is 2.0 to 6.0. Preferably there is. If this ratio is less than 1.5, the effect of improving impact resistance is small, and it is difficult to produce glass fibers having this ratio exceeding 10.
The glass fiber (C) used in the present invention has a fiber cross section having a major axis / minor axis of 1.5 to 10, so that the cross section is a flat shape. Specific examples of the flat cross sectional shape include a gourd shape, eyebrows A shape, an ellipse shape, an ellipse shape, a rectangle, or a shape similar to these is mentioned.
Moreover, it is preferable that the long diameter of the fiber cross section in glass fiber (C) is 10-50 micrometers, It is more preferable that it is 15-40 micrometers, It is further more preferable that it is 20-35 micrometers.
Furthermore, the ratio of the average fiber length and the average fiber diameter (aspect ratio) of the glass fiber (C) is preferably 2 to 200, more preferably 2.5 to 150, and 3 to 120. Is more preferable. When the aspect ratio is less than 2, the effect of improving the mechanical strength is small. On the other hand, when the aspect ratio exceeds 200, the anisotropy is increased and the appearance of the molded product is deteriorated. In addition, the average fiber diameter of the glass fiber which has a flat cross section means the number average fiber diameter when converting a flat cross section shape into the perfect circle of the same area.
The composition of the glass fiber (C) used in the present invention may be the same as that of a general glass fiber such as E glass, and any composition can be used as long as it can be made into a glass fiber. There is no particular limitation.

In this invention, the compounding quantity of glass fiber (C) needs to be 20-40 mass parts with respect to polylactic acid resin (A) 95-50 mass parts. When the blending amount of the glass fiber (C) is less than 20 parts by mass, the effect of imparting rigidity and impact resistance to the molded body cannot be sufficiently exhibited, and particularly in a thin-walled molded product, While formability is inferior, heat resistance cannot be imparted thereto. On the other hand, if the blending amount exceeds 40 parts by mass, the appearance of the molded product is deteriorated, and the production of the resin composition is difficult.

  In the present invention, as a method for promoting the crystallization of the polylactic acid resin (A), in addition to the method of blending the crystal nucleating agent (B) with the polylactic acid resin (A) as described above, the polylactic acid resin (A) Can be cross-linked by the (meth) acrylic acid ester compound (D) and the peroxide (E). Further, the crystal nucleating agent (B) may be blended with a crosslinked polylactic acid resin obtained by crosslinking the polylactic acid resin (A) with a (meth) acrylic acid ester compound (D) and a peroxide (E). .

In the present invention, the (meth) acrylic acid ester compound (D) is blended for the purpose of promoting crystallization of the resin composition and improving heat resistance, as described above.
Specific compounds include two or more (meth) acrylic molecules in the molecule because of high reactivity with the polylactic acid resin (A), less monomer, less toxicity, and less resin coloring. 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 the (meth) acrylic ester compound (C) 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 alkylenes thereof Copolymers of alkylenes with various glycol lengths, butanediol methacrylate, butanediol Acrylate, and the like.

  The addition amount of the (meth) acrylic acid ester compound (D) needs to be 0.01 to 20 parts by mass with respect to 100 parts by mass of the polylactic acid resin (A), and 0.05 to 1 part by mass. It is preferable that If the addition amount is less than 0.01 parts by mass, the desired heat resistance cannot be obtained, and if the addition amount exceeds 20 parts by mass, the operability during kneading decreases.

In the present invention, the peroxide (E) is blended for the purpose of promoting the reaction between the (meth) acrylic ester compound (D) and the polylactic acid resin (A) and improving the heat resistance. is there.
Specific examples of the peroxide (E) include benzoyl peroxide, bis (butylperoxy) trimethylcyclohexane, bis (butylperoxy) cyclododecane, butylbis (butylperoxy) valerate, dicumyl peroxide, butylperoxy Examples thereof include benzoate, dibutyl peroxide, bis (butylperoxy) diisopropylbenzene, dimethyldi (butylperoxy) hexane, dimethyldi (butylperoxy) hexyne, and butylperoxycumene.

  The added amount of the peroxide (E) is required to be 0.02 to 20 parts by mass, and 0.1 to 10 parts by mass with respect to 100 parts by mass of the polylactic acid resin (A). preferable. If the addition amount is less than 0.02 parts by mass, the intended effect cannot be obtained, and if the addition amount exceeds 20 parts by mass, the operability during kneading may decrease.

  Polylactic acid resin (A), crystal nucleating agent (B) and glass fiber (C) are mixed, or polylactic acid resin (A), (meth) acrylic acid ester compound (D) and peroxide (E) There is no particular limitation on the means for melt-kneading, and further mixing the crystal nucleating agent (B), the glass fiber (C), and the reactive compound (F) to be described later, but a uniaxial or biaxial extruder is used. And a method of melt kneading. 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 (A) + 5 ° C.) to (melting point of polylactic acid resin (A) + 100 ° C.), and the kneading time is preferably from 20 seconds to 30 minutes. When the temperature is lower than this range or for a short time, kneading or reaction becomes insufficient. On the other hand, when the temperature is high or for a long time, the resin may be decomposed or colored.

In the present invention, the resin composition preferably contains a reactive compound (F). By containing the reactive compound (F), the durability of the resin composition can be improved, and the flame retardancy and heat resistance can be stably maintained for a long period of time.
In the present invention, the reactive compound (F) is at least one selected from carbodiimide compounds, epoxy compounds, and oxazoline compounds.

As the carbodiimide compound, various compounds can be used and are not particularly limited as long as they have one or more carbodiimide groups in the molecule. For example, aliphatic monocarbodiimide, aliphatic polycarbodiimide, alicyclic mono Any substance in this range such as carbodiimide, alicyclic polycarbodiimide, aromatic monocarbodiimide, or aromatic polycarbodiimide can be used. Furthermore, you may have various heterocyclic rings or various functional groups in a molecule | numerator.
It does not specifically limit as a method of manufacturing a carbodiimide compound, Many methods, such as the method of manufacturing an isocyanate compound as a raw material, are mentioned.
As the 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 the 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-p-triylcarbodiimide, p-phenylene-bis-di-o-triylcarbodiimide, 4,4'-dicyclohexylmethanecarbodiimide, tetramethylxylylenecarbodiimide, N, N-dimethylphenylcarbodiimide , N, N′-di-2, - diisopropyl phenyl carbodiimide, include many carbodiimide skeleton.

Specific examples of the carbodiimide compound include many compounds. Examples of the alicyclic monocarbodiimide of the above classification include dicyclohexyl carbodiimide, and examples of the alicyclic polycarbodiimide of the above classification include 4 , 4'-dicyclohexylmethane diisocyanate and the like, and the aromatic monocarbodiimide of the above classification includes N, N'-diphenylcarbodiimide, N, N'-di-2,6-diisopropylphenyl. Examples of the aromatic polycarbodiimide of the above classification include polycarbodiimide derived from phenylene-p-diisocyanate and polycarbodiimide derived from 1,3,5-triisopropyl-phenylene-2,4-diisocyanate. Such as soil and the like.
In polycarbodiimide, both ends of the molecule or any part of the molecule has a functional structure such as an isocyanate group or a molecular structure different from other parts such as branched molecular chains. It doesn't matter.

  The addition amount of the reactive compound (F) is preferably 0.1 to 10 parts by mass and more preferably 0.2 to 5 parts by mass with respect to 100 parts by mass of the polylactic acid resin (A). . If the addition amount is less than 0.1 parts by mass, the intended durability may not be obtained, and if the addition amount exceeds 20 parts by mass, the heat resistance is lowered and is not economically preferable. The color tone may be greatly impaired.

  In the resin composition of the present invention, the pigment, heat stabilizer, antioxidant, inorganic filler, vegetable fiber, reinforcing fiber, weathering agent, plasticizer, lubricant, mold release agent, as long as the properties are not significantly impaired. An antistatic agent, an impact resistance agent, a compatibilizing agent and the like can be blended.

Examples of heat stabilizers and antioxidants include hindered phenols, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and the like.
Examples of inorganic fillers include talc, mica, calcium carbonate, zinc carbonate, wollastonite, alumina, magnesia, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, and carbon black. Zinc oxide, antimony trioxide, zeolite, hydrotalcite, metal fiber, metal whisker, ceramic whisker, potassium titanate, boron nitride, graphite, carbon fiber, layered silicate, etc. are exemplified. 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 the plasticizer include one or more plasticizers selected from aliphatic ester derivatives or aliphatic polyether derivatives. Specific examples of the compound include glycerin diacetomonocaprate and glycerin diacetomonolaurate. By blending the plasticizer, the dispersion of the crystal nucleating agent (B) into the polylactic acid resin (A) can be promoted.
As the lubricant, various carboxylic acid compounds can be used, and among them, various fatty acid metal salts, particularly magnesium stearate, calcium stearate and the like are preferable.
As the release agent, various carboxylic acid compounds, among them, various fatty acid esters, various fatty acid amides, and the like are preferably used.
The impact resistance agent is not particularly limited, and various materials such as a (meth) acrylic acid ester impact resistance agent having a core-shell structure can be used. Specific commercial products include, for example, Mitsubishi Rayon's Metabrene series.
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, For example, as a specific compound, poly (ethylene / glycidyl methacrylate) -polymethyl is mentioned, for example. Examples thereof include a methacrylate graft copolymer and a poly (ethylene / glycidyl methacrylate) -poly (acrylonitrile / styrene) graft copolymer. Specific examples of commercially available products include, for example, Nippon Oil & Fats Modiper Series.

Moreover, it is also possible to mix | blend resin other than polylactic acid resin (A) with the resin composition of this invention, and to make an alloy with polylactic acid resin (A).
Although it does not specifically limit as resin used as the alloy partner material of polylactic acid resin (A), For example, polyolefin, polyester, polyamide, polycarbonate, polystyrene, polymethyl (meth) acrylate, poly (acrylonitrile-butadiene-styrene) copolymer , Liquid crystal polymer, polyacetal and the like.
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 the 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 poly (butylene succinate). (Nate-lactic acid) copolymer, polyhydroxybutyric acid and the like.
Other polyesters include polycyclohexylene dimethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate terephthalate, polybutylene isophthalate terephthalate, polyethylene terephthalate / cyclohexylene dimethylene terephthalate, cyclohexyl. Examples include 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, and the like.

  The method for mixing these with the polylactic acid resin composition of the present invention is not particularly limited.

  The resin composition of the present invention can be molded into various molded products by molding methods such as injection molding, blow molding, extrusion molding, inflation molding, inbro, foamed sheet molding, and vacuum molding, pressure molding, and vacuum / pressure molding after sheet processing. It can be. That is, a molded body formed by injection molding, or a film or sheet formed by extrusion molding, a molded body processed from these films or sheets, or a hollow body formed by blow molding, and the hollow body It can be set as the molded object etc. which are processed from.

  In the present invention, 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 be employed. As an example of injection molding conditions suitable for the resin composition of the present invention, the cylinder temperature is equal to or higher than the melting point or flow start temperature of the resin composition, preferably 170 to 250 ° C, optimally in the range of 170 to 230 ° C, Further, it is appropriate that the mold temperature is not higher than (melting point−40 ° C.) of the resin composition. If the cylinder temperature is too low, the operability becomes unstable or overloading occurs, such as a short circuit in the molded product. Conversely, if the molding temperature is too high, the resin composition decomposes and the resulting molded product Problems such as reduction in strength and coloration are likely to occur, and both may be undesirable.

  The heat resistance of the resin composition of the present invention can be further improved by promoting crystallization during molding. As a method for this purpose, for example, there is a method of promoting crystallization in a mold at the time of injection molding, and in that case, the glass transition temperature of the resin composition is maintained above (melting point−40 ° C.). A method in which the molded product is held for a certain period of time in the mold and then removed from the mold is preferable. Moreover, even if it is a molded article taken out from the mold without taking such a method, crystallization can be promoted by heat treatment again at a glass transition temperature or higher and (melting point −40 ° C.) or lower. it can.

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.
In addition, the resin composition of the present invention can be formed into an extrusion-molded product such as a film, a sheet or a pipe, or a hollow molded product. Examples include many agricultural multi-films, construction sheets, various blow molded bottles, and the like.

  The resin composition of the present invention is particularly suitable for molding a thin-walled molded product among the molded products as described above. The thin-walled molded product is a resin molded product used for, for example, home appliances, parts of electric / electronic devices, and casings, and the average thickness is usually 2.0 mm or less, preferably 1.0 mm or less. A resin molded product having a flat plate portion at least in part.

Hereinafter, the present invention will be described more specifically with reference to examples. The measurement methods used for evaluation of the raw materials or the resin compositions of Examples and Comparative Examples are as follows.
(1) D-form content:
About 0.3 g of the polylactic acid resin (A) or the resin composition is added to 6 mL of 1N potassium hydroxide / methanol solution, and after sufficiently stirring at 65 ° C., 450 μL of sulfuric acid is added and stirred at 65 ° C., Polylactic acid was decomposed. 5 mL of this sample, 3 mL of pure water, and 13 mL of methylene chloride were mixed and shaken. After stationary separation, about 1.5 mL of the lower organic layer was collected, filtered through an HPLC disk filter having a pore size of 0.45 μm, and then subjected to GC measurement using HP-6890 Series GC system manufactured by Hewlett Packard. The ratio (%) of the peak area of D-lactic acid methyl ester in the total peak area of lactate methyl ester was calculated, and this was used as the D-form content (%).
(2) Melt flow rate (MFR):
The polylactic acid resin (A) or resin composition was measured at 190 ° C. according to JIS K7210.
(3) Molding cycle:
When a flat molded product with a thickness of 0.8 mm, width 50 mm, and length 85 mm is molded under predetermined molding conditions in an injection molding machine, the shortest required time (injection time + pressure holding time + cooling time) that the molded product can be taken out without deformation ) As the molding cycle. In addition, when the molding cycle exceeds 80 seconds, not only the molding workability is remarkably deteriorated, but also the influence of deterioration of the molten resin staying in the cylinder becomes large, and it is difficult to mold practically. Was 80 seconds.
(4) Thermal deformation temperature:
An ISO compliant test piece is molded under a predetermined molding condition in an injection molding machine, the thermal deformation temperature is measured with a load of 1.8 MPa according to ISO 75, and the thermal deformation temperature exceeds 100 ° C. The evaluation was made with ○ as ° C, 70-80 ° C as Δ, and less than 70 ° C as X.
(5) Flexural modulus:
An ISO-compliant test piece was molded under predetermined molding conditions in an injection molding machine and measured according to ISO178.
(6) Charpy impact value:
An ISO-compliant test piece was molded under predetermined molding conditions in an injection molding machine and measured according to ISO 179.
(7) Durability:
The molded ISO test piece is exposed to a high-temperature and high-humidity environment of 50 ° C. and 50% RH for 72 hours, and the bending strength is measured according to ISO 178. When it was -95%, it evaluated as (circle), 50-80%, (triangle | delta), and 50% or less evaluated as x.

Various raw materials used in Examples and Comparative Examples are as follows.
(1) Polylactic acid resin (A)
S-06: manufactured by Toyota, D body content = 0.2%, MFR = 4
・ S-09: Made by the same company, D-form content = 0.1%, MFR = 6
S-12: manufactured by the same company, D-form content = 0.1%, MFR = 8
S-17: manufactured by the same company, D-form content = 0.1%, MFR = 11
A-1: Made by the same company, D-form content = 0.6%, MFR = 2
TE-4000: manufactured by Unitika Ltd., D-form content = 1.4%, MFR = 10
Synthesis example 1:
2,000 g of L-lactide having a D-form content of 0.08% and 1.4 g of hexanediol are placed in a glass polymerization tube, heated and melted in a nitrogen stream, 0.4 g of dioctyltin is added, and 180 g is stirred. The reaction was carried out at 1 ° C. for 1 hour. After 30 minutes, 5 hPa, and then the produced poly L-
Lactic acid resin was dispensed. When the obtained poly L-lactic acid resin was measured by the above-described measurement method, the D-form content was 0.08% and the MFR was 15.

(2) Crystal nucleating agent (B)
・ Toyota KX238B (Polylactic acid based crystal nucleating agent containing 10% masterbatch)
N, N'-ethylenebis (12-hydroxystearic acid) amide: WX-1 manufactured by Kawaken Fine Chemical Co., Ltd.
N, N ′, N ″ -tricyclohexyltrimesic acid amide: TF-1 manufactured by Shin Nippon Rika Co., Ltd.
-Dimethyl sodium 5-sulfoisophthalate: manufactured by Tokyo Chemical Industry Co., Ltd.-Octanedicarboxylic acid dibenzoyl hydrazide: T-1287N manufactured by Adeka Company

(3) Glass fiber CSG 3PA-830S manufactured by Nitto Boseki Co., Ltd. (Fiber cross-section major axis = 28 μm, fiber cross-section minor axis = 7 μm, fiber cross-section major axis / minor axis = 4, cross-sectional shape = elliptical, aspect ratio = 100)
-CSG 3PA-820S manufactured by Nittobo Co., Ltd. (major axis of fiber section = 28 μm, minor axis of fiber section = 7 μm, major axis / minor axis of fiber section = 4, sectional shape = elliptical, aspect ratio = 100)
CSH 3PA-850 manufactured by Nitto Boseki Co., Ltd. (Fiber cross-section major axis = 20 μm, fiber cross-section minor axis = 10 μm, fiber cross-section major axis / minor axis = 2, cross-sectional profile = eyebrows, aspect ratio = 100)
・ 03JAFT592 manufactured by Owens Corning (Circular section chopped glass fiber, fiber diameter = 10 μm)

(4) (Meth) acrylic acid ester compound (D)
・ Ethylene glycol dimethacrylate: Bremer PDE-50 manufactured by NOF Corporation
(5) Peroxide (E)
・ Di-t-butyl peroxide: Perbutyl D manufactured by NOF Corporation
(6) Reactive compound (F)
・ Isocyanate-modified carbodiimide: LA-1 manufactured by Nisshinbo Co., Ltd. (isocyanate group content: 1 to 3%)
Carbodiimide: EN-160 manufactured by Matsumoto Yushi Seiyaku Co., Ltd.
(7) Crosslinking agent / hexamethylene diisocyanate (hereinafter referred to as HMDI)

Example 1
50 parts by mass of S-12 as polylactic acid resin (A), 20 parts by mass of KX238B (containing 10% of crystal nucleating agent) as crystal nucleating agent (B) (amount of crystal nucleating agent: 2 parts by mass), glass fiber (C ) Using 30 parts by mass of CSG 3PA-830S as a dry blend and supplying them from the root supply port of a twin screw extruder (TEM37BS manufactured by Toshiba Machine Co., Ltd.), and (meth) acrylic acid from the middle of the kneader A solution in which 0.1 part by mass of the ester compound (D) and 0.2 part by mass of the peroxide (E) are mixed is injected, and the vent is formed under the conditions of a barrel temperature of 180 ° C., a screw speed of 200 rpm, and a discharge of 15 kg / h. Extrusion was carried out with effect.
The obtained pellets were vacuum dried at 70 ° C. for 24 hours, and then the surface temperature of the mold was adjusted to 80 ° C. using an IS-80G injection molding machine manufactured by Toshiba Machine Co., Ltd. ) Was produced. During the preparation of the test piece, the molding cycle was measured. Then, the produced test piece was used for various measurements. A part of the test piece was exposed to a high temperature and high humidity environment of 50 ° C. and 50% RH for 100 hours, and the bending properties were measured.

Examples 2 to 21 and Comparative Examples 1 to 10
Resin composition in the same manner as in Example 1 except that polylactic acid resin, crystal nucleating agent, glass fiber, (meth) acrylic acid ester compound, peroxide, or presence / absence, type and amount of reactive compound were changed. Product pellets were obtained.
After drying the obtained pellets, a test piece for general physical property measurement (ISO type) was produced by injection molding, and at the same time, the molding cycle was measured. The produced test piece was used for various measurements.

  The evaluation results of Examples 1 to 23 and Comparative Examples 1 to 7 are collectively shown in Tables 1 and 2.

As is clear from Tables 1 and 2, in Examples 1 to 21, resin compositions excellent in rigidity, impact resistance and heat resistance were obtained, and moldability was also good.
In Examples 7 and 8, since the carbodiimide compound was blended as a reactive compound, excellent durability was obtained.
In Example 3, the compounding amount of the crystal nucleating agent was particularly high at 5 parts by mass, but no significant effect on moldability was found compared to other examples.
In Comparative Examples 1 to 4, glass fiber is not blended, or even if blended, the amount thereof is small, so both are inferior in rigidity and impact resistance, and inferior in heat resistance and moldability. It was.
In Comparative Example 5, since the amount of glass fiber was large, the operation during kneading was hindered, and the resin composition could not be sampled.
In Comparative Examples 6 and 7, since the cross section of the glass fiber used was not the shape defined in the present invention, the impact resistance was inferior and the moldability was slightly inferior.
In Comparative Example 8, the crystal nucleating agent did not satisfy the prescribed amount. In Comparative Example 2, the crystal nucleating agent, the (meth) acrylic acid ester compound, and the peroxide were not blended. As a result, the moldability was inferior.
In Comparative Examples 1, 9, and 10, since the D-form content of the polylactic acid resin exceeded the specified amount, the results were all inferior in heat resistance and moldability.

Claims (5)

95 to 50 parts by mass of polylactic acid resin (A) having a D-form content of 0.6% or less or 99.4% or more, 0.03 to 5 parts by mass of crystal nucleating agent (B), and fibers A crystalline polylactic acid resin composition containing 20 to 40 parts by mass of a glass fiber (C) having a major axis / minor axis of 1.5 to 10 in cross section , wherein the crystal nucleating agent (B) is N, N One or more selected from ', N "-tricyclohexyltrimesic acid amide, N, N'-ethylenebis (12-hydroxystearic acid) amide, octanedicarboxylic acid dibenzoyl hydrazide, and dimethyl metal salt of 5-sulfoisophthalic acid crystalline polylactic acid resin composition, characterized in that it. 95 to 50 parts by mass of polylactic acid resin (A) having a D-form content of 0.6% or less or 99.4% or more, and 0.01 to 20 masses of (meth) acrylic ester compound (D) And 0.02 to 20 parts by mass of peroxide (E) are melt-kneaded, and the crystal nucleating agent (B) is added to 0.03 to 95 to 50 parts by mass of the polylactic acid resin (A). and 5 parts by weight, a crystalline polylactic acid resin composition major axis / minor axis contains 20 to 40 parts by weight of glass fiber (C) 1.5 to 10 of the fiber cross section, the crystal nucleating agent ( B) is N, N ′, N ″ -tricyclohexyltrimesic acid amide, N, N′-ethylenebis (12-hydroxystearic acid) amide, octanedicarboxylic acid dibenzoylhydrazide, and dimethyl metal 5-sulfoisophthalate it is at least one selected from a salt Crystalline polylactic acid resin composition characterized. It contains 0.1 to 10 parts by mass of one or more reactive compounds (F) selected from carbodiimide compounds, epoxy compounds and oxazoline compounds with respect to 100 parts by mass of the polylactic acid resin (A). crystalline polylactic acid resin composition according to any one of claims 1-2. The molded object formed by shape | molding the crystalline polylactic acid resin composition in any one of Claims 1-3 . A thin-walled molded article obtained by injection molding the crystalline polylactic acid resin composition according to any one of claims 1 to 3 .