JP2011246558A - Polylactic acid resin composition, molded article, desktop mobile phone holder, internal chassis part for mobile phone, electronic equipment housing, and internal part for electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polylactic acid resin composition enabling water resistance and mechanical strength of a molded article thereof to be enhanced with good balance and enabling weld to be suppressed during being molded.SOLUTION: The polylactic acid resin composition comprises: (A) a polylactic acid; (B) a PMMA resin having a notched Charpy impact value stipulated by JIS K7111 of ≥5 kJ/m; and (C) an ABS resin having a proportion of styrene units of ≤70 mass%, a proportion of butadiene units of 10-16 mass% and an average particle diameter of ≤0.8 μm.

Description

  The present invention relates to a polylactic acid resin composition, and a molded product obtained by molding the polylactic acid resin composition, a desktop holder for a mobile phone, an internal chassis component for a mobile phone, a casing for an electronic device, and an internal component for an electronic device About.

  With the recent increase in interest in global environmental problems, development of plastic materials that are biodegradable without being excessively dependent on petroleum resources is desired. One of such plastic material candidates is polylactic acid.

  Since polylactic acid is easily hydrolyzed, there is a problem with the water resistance of the molded product, and it is required to provide the molded product with water resistance that can be put to practical use. In addition, polylactic acid is generally a hard and brittle material, and it has been practically necessary to improve the rigidity of the polylactic acid molded article, that is, to improve the mechanical strength such as tensile strength and tensile elastic modulus. Thus, conventionally, various measures for solving such problems have been studied.

  For example, in Patent Document 1, in order to increase the water resistance of a molded product and increase the mechanical strength, an ethylene-glycidyl methacrylate copolymer acrylonitrile-styrene copolymer, a graft copolymer, and a thermoplastic resin are converted into polylactic acid. It has been proposed to add carbodiimide after chemically blending with a representative aliphatic polyester resin and then chemically bonding. Patent Document 2 proposes adding a rubber component containing an epoxy group and a fibrillated fluororesin to a polylactic acid resin composition for improving the impact resistance of a molded product.

  Patent Document 3 discloses that the impact resistance of a molded product is improved by adding a multilayer structure polymer to polylactic acid.

JP 2007-145937 A JP 2008-291107 A JP 2009-263526 A

  However, even in the conventional improvement measures, the water resistance of the molded product is not always sufficient in practice. Also, a polylactic acid resin composition in which the water resistance and mechanical strength of the molded article are improved in a balanced manner has not been realized.

  Furthermore, the polylactic acid resin compositions disclosed in these documents have a problem that welds are likely to occur during molding, and it is difficult to improve the appearance of the molded product. It is a major obstacle to expansion.

  The present invention has been made in view of the above points, and provides a polylactic acid resin composition that can improve the water resistance and mechanical strength of a molded product in a well-balanced manner and can suppress welds during molding. The purpose is to provide.

  Another object of the present invention is to provide a molded body formed from the polylactic acid resin composition, a desktop holder for a mobile phone, an internal chassis component for a mobile phone, a casing for an electronic device, and an internal component for an electronic device. .

The polylactic acid resin composition according to the first invention contains the following components (A) to (C);
(A) polylactic acid;
(B) A PMMA resin having a notched Charpy impact value specified in JIS K7111 of 5 kJ / m ² or more;
(C) ABS resin having a styrene unit ratio of 72% by mass or less and a butadiene unit ratio of 10 to 16% by mass.

The polylactic acid resin composition according to the first invention may further contain the following component (D);
(D) A carbodiimide compound.

The polylactic acid resin composition according to the first invention may further contain the following component (E);
(E) 2,2-methylenebis- (4-methyl-6-tert-butylphenol), octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propanoate, bis (3-tert-butyl) Antioxidants selected from -4-hydroxy-5-methyl-phenyl) dicyclopentadiene.

  In the first invention, the component (A) may contain at least one selected from poly-L-lactic acid and stereocomplex polylactic acid.

  In the first invention, the content of the component (A) is in the range of 20 to 45 mass%, the content of the component (B) is in the range of 2 to 17 mass%, and the content of the component (C) is It may be 45% by mass or more.

The polylactic acid resin composition according to the first invention may further contain the following component (F);
(F) A compound that promotes crystallization of polylactic acid.

  The molded product according to the second invention is formed from the polylactic acid resin composition according to the first invention.

  The desktop holder for a mobile phone according to the third invention is formed from the polylactic acid resin composition according to the first invention.

  The internal chassis component of the mobile phone according to the fourth invention is formed from the polylactic acid resin composition according to the first invention.

  The casing for electronic equipment according to the fifth invention is formed from the polylactic acid resin composition according to the first invention.

  The internal part for electronic devices which concerns on 6th invention is formed from the polylactic acid resin composition which concerns on 1st invention.

  According to the present invention, the water resistance and mechanical strength of a molded product formed from the polylactic acid resin composition can be improved in a well-balanced manner, and the weld appearance during molding can be suppressed to improve the appearance of the molded product.

The polylactic acid resin composition according to this embodiment contains the following components (A) to (C).
(A) polylactic acid;
(B) A PMMA resin having a notched Charpy impact value defined by JIS K7111 of 5 kJ / m ² or more.
(C) ABS resin having a styrene unit ratio of 70% by mass or less, a butadiene unit ratio of 10 to 16% by mass, and an average particle size of 0.8 μm or less.

  For this reason, the water resistance and mechanical strength of the molded product obtained by molding this polylactic acid resin composition are improved in a well-balanced manner, and in particular, by containing the component (C), welding during molding can be suppressed. And the appearance of the molded product is improved. Below, the detail of the component contained in a polylactic acid resin composition is demonstrated.

[(A) component]
Examples of the component (A) (polylactic acid) include a homopolymer of lactic acid and a copolymer of lactic acid and a hydroxycarboxylic acid other than lactic acid. Polylactic acid can be obtained, for example, by fermenting starch obtained from plants such as corn to obtain lactic acid, and then polymerizing the lactic acid by chemical synthesis.

  Examples of lactic acid include L-lactic acid, D-lactic acid, and a lactone that is a dimer of lactic acid.

  Examples of hydroxycarboxylic acids other than lactic acid that can be copolymerized with lactic acid include glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxypentanoic acid, and hydroxycaproic acid. These hydroxycarboxylic acids can be used alone or in combination of two or more.

  The component (A) preferably contains at least one of poly-L-lactic acid, which is a polymer of L-lactic acid, and stereocomplex polylactic acid. In particular, the component (A) is preferably composed only of stereocomplex polylactic acid, or is composed only of poly-L-lactic acid and stereocomplex polylactic acid.

  Stereocomplex-type polylactic acid is a mixture of poly-L-lactic acid and poly-D-lactic acid, which are optical isomers, and a stereocomplex crystal is produced by pairing them (Macromolecules 1987, 20, 904-906). This stereocomplex-type polylactic acid is a crystalline resin having a remarkably higher melting point than poly-L-lactic acid, and can be expected to have characteristics significantly superior to poly-L-lactic acid.

  Poly-L-lactic acid and poly-D-lactic acid are substantially composed of an L-lactic acid unit and a D-lactic acid unit represented by the following [Chemical Formula 1], respectively.

  The poly-L-lactic acid constituting the stereocomplex type polylactic acid is preferably composed of 90 to 100 mol%, more preferably 95 to 100 mol%, still more preferably 99 to 100 mol% of L-lactic acid units. Examples of other units include D-lactic acid units and units other than lactic acid. The D-lactic acid unit and the units other than lactic acid are preferably 0 to 10 mol%, more preferably 0 to 5 mol%, and still more preferably 0 to 1 mol%.

  The poly-D-lactic acid constituting the stereocomplex type polylactic acid is preferably composed of 90 to 100 mol%, more preferably 95 to 100 mol%, still more preferably 99 to 100 mol% of D-lactic acid units. Examples of other units include L-lactic acid units and units other than lactic acid. L-lactic acid units and units other than lactic acid are 0 to 10 mol%, preferably 0 to 5 mol%, more preferably 0 to 1 mol%.

  Units other than lactic acid include units derived from dicarboxylic acids, polyhydric alcohols, hydroxycarboxylic acids, lactones and the like having functional groups capable of forming two or more ester bonds, and various polyesters and various polyesters composed of these various components. Examples are units derived from ether, various polycarbonates and the like.

  Examples of the dicarboxylic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, terephthalic acid, and isophthalic acid. Polyhydric alcohols include ethylene glycol, propylene glycol, propanediol, butanediol, pentanediol, hexanediol, octanediol, glycerin, sorbitan, neopentyl glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol And aliphatic polyhydric alcohols such as those obtained by adding ethylene oxide to bisphenol. Examples of the hydroxycarboxylic acid include glycolic acid, hydroxybutyric acid, 4-hydroxybenzoic acid and the like. Examples of the lactone include glycolide, ε-caprolactone glycolide, ε-caprolactone, β-propiolactone, δ-butyrolactone, β- or γ-butyrolactone, pivalolactone, δ-valerolactone, and the like.

  Stereocomplex polylactic acid is a mixture of poly-L-lactic acid and poly-D-lactic acid, and can form stereocomplex crystals. The weight average molecular weight of poly-L-lactic acid is preferably 150,000 to 210,000. The weight average molecular weight of poly-D-lactic acid is preferably 130,000 to 160,000. Thus, by making a difference in the weight average molecular weight, it becomes easy to form a stereo complex, and it becomes easier to form a stereo complex having a higher molecular weight.

  Poly-L-lactic acid and poly-D-lactic acid constituting the stereocomplex type polylactic acid can be produced by a known method. For example, L- or D-lactide can be produced by heating and ring-opening polymerization in the presence of a metal polymerization catalyst. Moreover, after crystallizing low molecular weight polylactic acid containing a metal polymerization catalyst, it can be produced by solid phase polymerization by heating under reduced pressure or in an inert gas stream. Further, it can be produced by a direct polymerization method in which lactic acid is subjected to dehydration condensation in the presence / absence of an organic solvent.

  The polymerization reaction can be carried out in a conventionally known reaction vessel. For example, a vertical reactor or a horizontal reactor equipped with a stirring blade for high viscosity, such as a helical ribbon blade, can be used alone or in parallel. Moreover, any of a batch type, a continuous type, a semibatch type may be sufficient, and these may be combined.

  Alcohol may be used as a polymerization initiator. The alcohol is preferably non-volatile without inhibiting the polymerization of polylactic acid. For example, decanol, dodecanol, tetradecanol, hexadecanol, octadecanol and the like can be suitably used.

  In the solid phase polymerization method, a relatively low molecular weight lactic acid polyester obtained by the above-described ring-opening polymerization method or lactic acid direct polymerization method is used as a prepolymer. It can be said that the prepolymer is preferably crystallized in advance in the temperature range of the glass transition temperature (Tg) or higher and lower than the melting point (Tm) from the viewpoint of preventing fusion. The crystallized prepolymer is filled in a fixed vertical or horizontal reaction vessel, or a reaction vessel (rotary kiln, etc.) where the vessel itself rotates like a tumbler or kiln, and the prepolymer glass transition temperature (Tg) or higher. Heated to a temperature range below the melting point (Tm). There is no problem even if the polymerization temperature is raised stepwise as the polymerization proceeds. In addition, for the purpose of efficiently removing water generated during solid phase polymerization, a method of reducing the pressure inside the reaction vessels or circulating a heated inert gas stream is also preferably used.

  The ratio of poly-L-lactic acid to poly-D-lactic acid in the stereocomplex type polylactic acid is preferably in the range of 90:10 to 10:90 by mass ratio, and in the range of 75:25 to 25:75. It is more preferable if it is in the range of 60:40 to 40:60, and it is more preferable that this ratio is closer to 50:50.

  The weight average molecular weight of the stereocomplex type polylactic acid is preferably in the range of 100,000 to 500,000, more preferably in the range of 100,000 to 300,000. This weight average molecular weight is a standard polystyrene equivalent weight average molecular weight determined by gel permeation chromatography using chloroform as a solvent (mobile phase).

  The stereocomplex polylactic acid is preferably composed of poly-L-lactic acid and poly-D-lactic acid to form a stereocomplex crystal. The content of stereocomplex crystals is preferably 80 to 100%, more preferably 95 to 100%. The stereocomplex polylactic acid referred to in the present invention is preferably 80% or more, more preferably 90% or more of the melting peak at 195 ° C. or higher in the melting peak in the temperature rising process in the differential scanning calorimeter (DSC) measurement. More preferably, it is 95% or more. The melting point is in the range of 195 to 250 ° C, more preferably in the range of 200 to 220 ° C. The melting enthalpy is 20 J / g or more, preferably 30 J / g or more. Specifically, in the differential scanning calorimeter (DSC) measurement, the ratio of the melting peak at 195 ° C. or higher in the melting peak in the temperature rising process is 90% or higher, and the melting point is in the range of 195 to 250 ° C. It is preferable that the melting enthalpy is 20 J / g or more.

  The stereocomplex type polylactic acid preferably has a stereogenicity of 90% or more, more preferably 100%. The degree of stereo (S) can be determined by the following equation by comparing the enthalpies of melting point in DSC measurement.

S = [(ΔHms / ΔHms ⁰ ) / (ΔHmh / ΔHmh ⁰ + ΔHms / ΔHms ⁰ )]
(However, ΔHms ⁰ = 203.4 J / g, ΔHmh ⁰ = 142 J / g, ΔHms is the melting enthalpy of melting of the stereocomplex, and ΔHmh is the melting enthalpy of the homocrystal.)
Stereocomplex-type polylactic acid can be obtained by mixing poly-L-lactic acid and poly-D-lactic acid together at a predetermined mass ratio. Mixing can be performed in the presence of a solvent. The solvent is not particularly limited as long as it dissolves poly-L-lactic acid and poly-D-lactic acid. For example, chloroform, methylene chloride, dichloroethane, tetrachloroethane, phenol, tetrahydrofuran, N-methylpyrrolidone, N, N-dimethylformamide, butyrolactone, trioxane, hexafluoroisopropanol and the like can be used. Only one kind of these solvents can be used, and a plurality of kinds of solvents can be used in combination.

  In addition, stereocomplex polylactic acid can be obtained by mixing poly-L-lactic acid and poly-D-lactic acid in the absence of a solvent. In this case, for example, a method of melt-kneading poly-L-lactic acid and poly-D-lactic acid, or melting one of poly-L-lactic acid and poly-D-lactic acid and then adding the other to knead The method to do can be adopted.

  Further, as a stereocomplex polylactic acid, a stereoblock polylactic acid having a structure in which a poly-L-lactic acid segment and a poly-D-lactic acid segment are bonded can also be suitably used. Stereoblock polylactic acid is a block polymer in which a poly-L-lactic acid segment and a poly-D-lactic acid segment are bonded in the molecule. Such a block polymer is, for example, a method of producing by sequential ring-opening polymerization or a method of polymerizing poly-L-lactic acid and poly-D-lactic acid and then binding them with a chain exchange reaction or a chain extender. The above-mentioned basic methods such as a method of polymerizing poly-L-lactic acid and poly-D-lactic acid, blending and then solid-phase polymerizing to extend the chain, a method of producing from racemic lactide using a stereoselective ring-opening polymerization catalyst, etc. Any block copolymer having a structure can be used regardless of the production method. However, it is more preferable from the viewpoint of ease of production to use a high-melting stereoblock polymer obtained by sequential ring-opening polymerization and a polymer obtained by a solid phase polymerization method.

  It is preferable to add a specific additive to the stereocomplex type polylactic acid in order to improve the degree of stereoification. As such an additive, a metal phosphate represented by the following [Chemical Formula 2] is given as a preferred example.

In the formula, R ⁵ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. R ^{6 to} R ⁹ each independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and an octyl group.

M ¹ represents an alkali metal atom, an alkaline earth metal atom, a zinc atom or an aluminum atom. Examples of M ¹ include Na, K, Al, Mg, and Ca. In particular, K, Na, and Al can be preferably used. n represents 0 when M ¹ is an alkali metal atom, an alkaline earth metal atom, or a zinc atom, and represents 1 or 2 when M ¹ is an aluminum atom.

  These metal phosphates are preferably used in a mass ratio of 10 ppm to 2%, more preferably 50 ppm to 0.5%, still more preferably 100 ppm to 0.3% with respect to the stereocomplex type polylactic acid. . If the amount is too small, the effect of improving the degree of stereoization is small.

  Moreover, in order to improve the heat resistance of the polylactic acid resin composition, it is preferable to further add calcium silicate. As calcium silicate, what contains a hexagonal crystal can be used, for example, and the one where the particle diameter is low is preferable. For example, when the average primary particle diameter is in the range of 0.2 to 0.05 μm, the polylactic acid resin composition is appropriately dispersed, so that the heat resistance of the polylactic acid resin composition is good. Further, the addition amount is preferably in the range of 0.01 to 1% by mass, more preferably in the range of 0.05 to 0.5% by mass, based on the polylactic acid resin composition. If the amount is too large, the appearance tends to deteriorate, and if the amount is too small, no particular effect is exhibited, which is not preferable.

  Moreover, it is preferable that the carboxyl end group density | concentration of stereocomplex type polylactic acid with respect to a polylactic acid resin composition is 15 eq / ton or less. When it is within this range, a composition having good melt stability and wet heat durability can be obtained. In the case of 15 eq / ton or less, specifically, any of the known methods for reducing the carboxyl end group concentration in the polyester can be employed. For example, addition of a terminal blocking agent, specifically, oxazoline Ester, amidation with alcohol or amine without addition of condensing agents such as monocarbodiimides, dicarbodiimides, polycarbodiimides, or without end-capping agents or condensing agents. You can also.

  When the component (A) contains poly-L-lactic acid, as poly-L-lactic acid, poly-L-lactic acid used for the production of the stereocomplex polylactic acid can be used, and a commercially available product can be used. A thing can be used suitably. When stereocomplex polylactic acid and poly-L-lactic acid are used in combination, the content of poly-L-lactic acid is preferably 30% by mass or less based on the total amount of polylactic acid resin. When this content exceeds 30% by mass, there is a possibility that the improvement of the rigidity of the molded product due to the inclusion of the stereocomplex type polylactic acid cannot be sufficiently achieved. The molecular weight of the poly-L-lactic acid is not particularly limited, but the weight average molecular weight is preferably 10,000 or more, more preferably 30,000 or more from the viewpoint of physical and thermal characteristics.

The content of the component (A) in the polylactic acid resin composition is preferably in the range of 25 to 45% by mass. When the content is 25% by mass or more, the mechanical strength of a molded product formed from the polylactic acid resin composition can be sufficiently improved. Furthermore, the content of the component (A) in the polylactic acid resin composition can be sufficiently increased to sufficiently reduce the amount of petroleum resources used, and can greatly contribute to the reduction of CO ₂ emissions. In addition, it becomes possible to receive the biomass plastic identification display by Japan Bioplastics Association because the (A) component which is a biomass component is 25 mass% or more. Moreover, the fall of the water resistance of the molded article by hydrolysis of polylactic acid resin is suppressed because content of (A) component is 45 mass% or less.

[Component (B)]
Part or all of the polymethyl methacrylate resin (PMMA resin) as the component (B) may be a polymethyl methacrylate resin elastomer (PMMA resin elastomer).

As described above, the component (B) needs to have a notched Charpy impact value specified in JIS K7111 of 5 kJ / m ² or more. This notched Charpy impact value is particularly preferably 5.3 kJ / m ² or more. The upper limit of the Charpy impact value with a notch is not particularly limited.

  Examples of such PMMA resins include Sumipex HT03Y and Sumipex HT01X manufactured by Sumitomo Chemical Co., Ltd., and Sumipex HT01X is particularly preferable.

  This component (B) inhibits crystallization of polylactic acid after molding of the polylactic acid resin composition. For this reason, the dimensional stability of the molded product under high temperature conditions is improved, and the impact resistance of the molded product is further improved. Furthermore, this component (B) improves the heat resistance of the molded product.

  The content of the component (B) in the polylactic acid resin composition is preferably in the range of 2 to 17% by mass. When the content is 2% by mass or more, the dimensional stability, impact resistance, and heat resistance of the molded product are particularly improved. When the content is 17% by mass or less, the polylactic acid resin composition has high fluidity. Is maintained.

[Component (C)]
The proportion of styrene units in the ABS resin (acrylonitrile / butadiene / styrene copolymer resin) contained in the component (C) is 72% by mass or less, and the proportion of butadiene units is 10 to 16% by mass.

  The lower limit of the ratio of the styrene unit is not particularly limited, but is preferably 30% by mass or more. Particularly, when the ABS resin is substantially composed of only an acrylonitrile unit, a butadiene unit and a styrene unit, it is 60% by mass or more. Preferably there is.

  The ratio of the acrylonitrile unit in the ABS resin is, for example, in the range of 1.5 to 30% by mass. When the ABS resin is substantially composed of only the acrylonitrile unit, the butadiene unit and the styrene unit, for example, 15 to 30% by mass. Range.

The ABS resin may contain units other than acrylonitrile units, butadiene units, and styrene units, and may contain, for example, methyl methacrylate units. The proportion of methyl methacrylate units in the ABS resin is, for example, 60% by mass or less.
ABS resin The ratio of acrylonitrile unit, styrene unit, butadiene unit, methyl methacrylate unit, etc. in the ABS resin is based on the NMR measurement result of the ABS resin, and the gradient polymer elution chromatography (GPEC) of the ABS resin. Derived based on the measurement result.

  The average particle size of the ABS resin is not particularly limited, but is, for example, in the range of 0.3 to 0.9 μm. This average particle diameter is a volume average particle diameter measured by a laser diffraction scattering method with a laser diffraction / scattering particle size analyzer (such as Microtrack MT3000II series manufactured by Nikkiso Co., Ltd.).

  The method for synthesizing the ABS resin is not particularly limited, but it is preferably produced by an emulsion polymerization method or a bulk polymerization method.

  By using such an ABS resin, weld during molding of the polylactic acid resin composition is suppressed, and the appearance of the molded product is improved. Further, by using such an ABS resin, the color developability when the molded product is colored is excellent.

  The content of the component (C) in the polylactic acid resin composition is preferably 45% by mass or more, and particularly preferably in the range of 45 to 78% by mass.

  Furthermore, the content of the component (C) is preferably 50% by volume or more, particularly preferably in the range of 50 to 80% by volume, with respect to the total amount of the resin components in the polylactic acid resin composition. The resin component in the polylactic acid resin composition refers to the component (A), the component (B), the component (C), and a thermoplastic resin other than these (component (G) described later).

  Within the above range, the moldability of the polylactic acid resin composition is particularly excellent, and the occurrence of welds is remarkably suppressed.

[(D) component]
The polylactic acid resin composition may contain a component (D) (carbodiimide compound). (D) As a compound contained in a component, a polycarbodiimide compound, a monocarbodiimide compound, etc. are mentioned. When the component (D) is used, the component (D) reacts with part or all of the carboxyl group terminals of the polylactic acid resin to block the water, thereby further improving the water resistance of the molded product. improves. For this reason, the durability of the molded product in a high temperature and high humidity environment is further improved.

  Examples of the polycarbodiimide compound include poly (4,4′-diphenylmethanecarbodiimide), poly (4,4′-dicyclohexylmethanecarbodiimide), poly (1,3,5-triisopropylbenzene) polycarbodiimide, and poly (1,3 , 5-triisopropylbenzene and 1,5-diisopropylbenzene) polycarbodiimide. Examples of the monocarbodiimide compound include N, N′-di-2,6-diisopropylphenylcarbodiimide.

  As the polycarbodiimide compound and the monocarbodiimide compound, commercially available products can be used as appropriate. Specific examples thereof include trade name Carbodilite LA-1 (poly (4,4′-dicyclohexylmethanecarbodiimide)) manufactured by Nisshinbo Industries, Ltd.

  When (D) component is used, it is preferable that content of (D) component in a polylactic acid resin composition exists in the range of 0.1-5 mass%. If the content is less than 0.1% by mass, the improvement in durability is not expected so much, and if it exceeds 5% by mass, the mechanical strength of the molded product tends to decrease.

  When the component (D) is used, when the polylactic acid and only the component (D) are mixed in advance during the preparation of the polylactic acid resin composition to prepare a master batch, the component (D) is used. The said effect | action is exhibited effectively.

[(E) component]
The polylactic acid resin composition may contain the following component (E).
(E) 2,2-methylenebis- (4-methyl-6-tert-butylphenol), octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propanoate, bis (3-tert-butyl) Antioxidants selected from -4-hydroxy-5-methyl-phenyl) dicyclopentadiene.

  When these antioxidants are used, the molding stability of the polylactic acid resin composition is improved, and contamination of the mold surface during molding is suppressed.

  When the component (E) is used, the content of the component (E) in the polylactic acid resin composition is preferably in the range of 100 to 500 ppm on a mass basis. Within this range, the improvement in molding stability of the polylactic acid resin composition as described above and the suppression of dirt on the mold surface at the time of molding remarkably appear.

[(F) component]
The polylactic acid resin composition may contain a component (F) (a compound that promotes crystallization of polylactic acid). Examples of the compound contained in the component (F) include a polylactic acid nucleating agent (crystal nucleating agent).

  When the polylactic acid resin composition contains the component (F), crystallization of the polylactic acid is promoted by the component (F) at the time of molding the polylactic acid resin composition, so that the dimension of the molded product under high temperature conditions is stabilized. Improves. In addition, the crystallization of polylactic acid during molding is promoted, so that the retention time in the mold is shortened and the crystallization of polylactic acid is sufficiently advanced to give the molded article high heat resistance and elastic modulus. be able to.

  An example of a nucleating agent is talc. Talc also contributes to an improvement in the tensile modulus of the molded product. As talc, a commercially available appropriate one can be used. The average particle diameter of the talc is usually preferably in the range of 0.1 to 12 μm. The average particle diameter is more preferably 0.5 μm or more, and further preferably 10 μm or less. This average particle diameter is a value measured by a laser diffraction / scattering method using a laser diffraction / scattering particle size analyzer (such as Microtrack MT3000II series manufactured by Nikkiso Co., Ltd.).

  The content of talc in the polylactic acid resin composition is preferably in the range of 1 to 30% by mass. When the content is less than 1% by mass, the tensile elastic modulus of the molded product is not sufficiently improved. Also, if this content exceeds 30%, it becomes difficult to form a pellet, for example, part of the talc will not bite into the screw during the kneading of the polylactic acid resin composition. It will decline. The content of talc is preferably in the range of 1 to 15% by mass, more preferably in the range of 3 to 8% by mass. When the content is 8% by mass or less, the occurrence of welds is sufficiently suppressed even when a molded product having a complicated shape is obtained, and when the content is 3% by mass or more, the addition of talc. The effect by is particularly remarkable.

  Zinc phosphinate may be used as a nucleating agent. Examples of zinc phosphinate include zinc phenylphosphinate and zinc diphenylphosphinate. The phenyl group in the zinc phenylphosphinate or zinc diphenylphosphinate may have a substituent. Examples of the substituent include an alkyl group having 1 to 10 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, and a t-butyl group, and methoxycarbonyl. Group, an alkoxycarbonyl group having 1 to 10 carbon atoms, such as an ethoxycarbonyl group. Specific examples of such zinc phosphinate include phenylphosphinic acid, 4-methylphenylphosphinic acid, 4-ethylphenylphosphinic acid, 4-n-propylphenylphosphinic acid, 4-i-propylphenylphosphinic acid, 4- n-butylphenylphosphinic acid, 4-i-butylphenylphosphinic acid, 4-t-butylphenylphosphinic acid, 3,5-dimethoxycarbonylphenylphosphinic acid, 3,5-diethoxycarbonylphenylphosphinic acid, 2,5- Dimethoxycarbonylphenylphosphinic acid, 2,5-diethoxycarbonylphenylphosphinic acid, etc., diphenylphosphinic acid, di-4-methylphenylphosphinic acid, di-4-ethylphenylphosphinic acid, di-4-t-butylphenylphosphine Acid, di-3,5- Methoxycarbonylphenyl phosphinic acid, di-3,5-di-ethoxycarbonyl phenyl phosphinic acid and the like.

  In order for zinc phosphinate to act effectively as a nucleating agent, the average particle size is preferably in the range of 0.1 to 3 μm. The average particle diameter is a value measured by the laser diffraction scattering method as described above.

  Zinc phosphinate contributes to an improvement in the tensile modulus of the molded product. The content of zinc phosphinate is preferably 0.5% by mass or more. When the content is less than 0.5% by mass, the tensile modulus of the molded product cannot be improved. Moreover, the upper limit of content of zinc phosphinate is not particularly limited. However, if this content exceeds 3% by mass, the effect of improving the tensile modulus of the molded product is saturated, and there is no practical meaning, so this content may be 3% by mass or less. preferable.

  As the nucleating agent other than the talc and polyphosphinic acid, a nucleating agent that dissolves in the polylactic acid resin in the polylactic acid resin composition may be used. Dissolving in a polylactic acid resin means that it becomes transparent when the polylactic acid resin and the nucleating agent are kneaded at a temperature equal to or higher than the melting point. When such a nucleating agent is used, the water resistance of the molded product is further improved. As such a nucleating agent, a commercially available appropriate agent is used, for example, N, N ′, N ″ -tricyclohexyltrimesic acid amide (product number TF1 manufactured by Shin Nippon Chemical Co., Ltd.) or the like is used.

  Although content of the nucleating agent melt | dissolved in the polylactic acid resin in a polylactic acid resin composition is adjusted suitably, it is preferable that it is the range of 0.5-3 mass%. When the content is 0.5% by mass or more, the hydrolysis resistance is particularly improved. However, when the content exceeds 3% by mass, the effect of improving the hydrolysis resistance is saturated.

  In the polylactic acid resin composition, a nucleating agent that does not dissolve in the polylactic acid resin in the polylactic acid resin composition may be contained as a nucleating agent other than the above. “Not dissolved in polylactic acid resin” means that it becomes opaque when they are kneaded at a temperature equal to or higher than the melting point of the polylactic acid resin and the nucleating agent. When such a nucleating agent is used, the water resistance of the molded product is further improved. As such a nucleating agent, an appropriate one that is commercially available is used, for example, product number LAK401 manufactured by Takemoto Yushi Co., Ltd. is used.

  Moreover, as a nucleating agent, KX238B manufactured by Toyota (a master batch containing 10% polylactic acid-based crystal nucleating agent), N, N′-ethylenebis (12-hydroxystearic acid) amide (WX-1 manufactured by Kawaken Fine Chemical Co., Ltd.) Further, dimethyl sodium 5-sulfoisophthalate (manufactured by Tokyo Chemical Industry Co., Ltd.), dibenzoyl hydrazide octanedicarboxylic acid (T-1287N manufactured by Adeka Corporation), etc. may be used.

  The content of the nucleating agent that does not dissolve in the polylactic acid resin in the polylactic acid resin composition is appropriately adjusted, but is preferably in the range of 0.5 to 3% by mass. When the content is 0.5% by mass or more, the hydrolysis resistance is particularly improved. However, when the content exceeds 3% by mass, the effect of improving the hydrolysis resistance is saturated.

  In order to improve the dispersibility of the nucleating agent that does not dissolve in the polylactic acid resin in the polylactic acid resin composition, the nucleating agent is mixed (preliminarily mixed) with an appropriate inorganic filler in advance and then other components. It is preferable that a polylactic acid resin composition is prepared by mixing with. In this case, the inorganic filler serves as a dusting agent, and aggregation of fine nucleating agents is suppressed. As this inorganic filler, talc which is also a nucleating agent is particularly preferable. The amount of the inorganic filler used for the premixing is preferably in the range of 100 to 200% by mass with respect to the nucleating agent not dissolved in the polylactic acid resin, and the average particle size of the inorganic filler is polylactic acid. It is preferably in the range of 1 to 2 times the average particle size of the nucleating agent that does not dissolve in the resin.

[(G) component]
The component (G) (thermoplastic resin not contained in each of the above components) may include various thermoplastic resins. (G) The preferable component which may be contained in a component is demonstrated.

((G1) Polycarbonate resin)
The polylactic acid resin composition may contain a polycarbonate resin as at least a part of the component (G). In this case, the water resistance of the molded product is further improved. A commercially available product is appropriately used as the polycarbonate resin. The content of the polycarbonate resin in the polylactic acid resin composition is preferably in the range of 1 to 20% by mass. If the content is less than 1% by mass, the improvement of hydrolysis resistance of the molded product is not expected so much. If the content exceeds 20% by mass, the ratio of the polylactic acid resin to the whole resin component is decreased, and polylactic acid There is a possibility that biodegradability, which is a characteristic of the resin, is lowered.

  Examples of the polycarbonate resin include aromatic polycarbonate resins obtained by reacting a dihydric phenol and a carbonate precursor. Examples of the reaction method include an interfacial polycondensation method, a melt transesterification method, a solid phase transesterification method of a carbonate prepolymer, and a ring-opening polymerization method of a cyclic carbonate compound.

  Representative examples of dihydric phenols include hydroquinone, resorcinol, 4,4'-biphenol, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol) A), 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 2,2-bis (4-hydroxyphenyl) pentane, 4,4 '-(P-phenylenediisopropylidene) diphenol, 4,4'-(m-phenylenediisopropylidene) diph 1,1-bis (4-hydroxyphenyl) -4-isopropylcyclohexane, bis (4-hydroxyphenyl) oxide, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfoxide, bis (4- Hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) ester, bis (4-hydroxy-3-methylphenyl) sulfide, 9,9-bis (4-hydroxyphenyl) fluorene, 9 , 9-bis (4-hydroxy-3-methylphenyl) fluorene. A preferred dihydric phenol is bis (4-hydroxyphenyl) alkane, and bisphenol A (BPA) is particularly preferred because it can improve the toughness of the molded product.

  Examples of the carbonate precursor include carbonyl halide, carbonic acid diester, and haloformate. Specific examples include phosgene, diphenyl carbonate, and dihaloformate of dihydric phenol.

  When producing aromatic polycarbonate resin from dihydric phenol and carbonate precursor by interfacial polymerization method, use catalyst, terminal terminator, antioxidant to prevent oxidation of dihydric phenol as necessary. May be.

  The component (G1) includes a branched polycarbonate resin copolymerized with a trifunctional or higher polyfunctional aromatic compound, and a polyester carbonate resin copolymerized with an aromatic or aliphatic (including alicyclic) difunctional carboxylic acid. Further, a copolymer polycarbonate resin copolymerized with a bifunctional alcohol (including alicyclic), a polyester carbonate resin copolymerized with the bifunctional carboxylic acid and the bifunctional alcohol, and the like may be included. Further, the component (G1) may contain two or more kinds of polycarbonate resins.

  The branched polycarbonate resin increases the melt tension of the polylactic acid resin composition, and the molding processability in extrusion molding, foam molding, blow molding and the like is improved based on this characteristic. As a result, a molded product having better dimensional accuracy can be obtained. Examples of the trifunctional or higher polyfunctional aromatic compound used for obtaining the branched polycarbonate resin include 4,6-dimethyl-2,4,6-tris (4-hydroxydiphenyl) heptene-2, 2,4, 6-trimethyl-2,4,6-tris (4-hydroxyphenyl) heptane, 1,3,5-tris (4-hydroxyphenyl) benzene, 1,1,1-tris (4-hydroxyphenyl) ethane, , 1,1-tris (3,5-dimethyl-4-hydroxyphenyl) ethane, 2,6-bis (2-hydroxy-5-methylbenzyl) -4-methylphenol, 4- {4- [1,1 A preferred example is trisphenol such as -bis (4-hydroxyphenyl) ethyl] benzene} -α, α-dimethylbenzylphenol. Other polyfunctional aromatic compounds include phloroglucin, phloroglucide, tetra (4-hydroxyphenyl) methane, bis (2,4-dihydroxyphenyl) ketone, 1,4-bis (4,4-dihydroxytriphenylmethyl) Examples include benzene, trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, and acid chlorides thereof. Of these, 1,1,1-tris (4-hydroxyphenyl) ethane and 1,1,1-tris (3,5-dimethyl-4-hydroxyphenyl) ethane are preferable, and 1,1,1-tris (4 -Hydroxyphenyl) ethane is preferred.

The structural unit derived from the polyfunctional aromatic compound in the branched polycarbonate resin is 0 in a total of 100 mol% of the structural unit derived from the dihydric phenol and the structural unit derived from the polyfunctional aromatic compound. 0.03 to 1 mol%, preferably 0.07 to 0.7 mol%, particularly preferably 0.1 to 0.4 mol%. The branched structural unit is not only derived from a polyfunctional aromatic compound, but also derived from a side reaction during a melt transesterification reaction without using a polyfunctional aromatic compound. Also good. The ratio of the branched structure can be calculated by ¹ H-NMR measurement.

  On the other hand, the aliphatic bifunctional carboxylic acid is preferably α, ω-dicarboxylic acid, and specific examples thereof include sebacic acid (decanedioic acid), dodecanedioic acid, tetradecanedioic acid, octadecanedioic acid, icosane diacid. Examples thereof include linear saturated aliphatic dicarboxylic acids such as acids and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. As the bifunctional alcohol, an alicyclic diol is suitable, and examples thereof include cyclohexanedimethanol, cyclohexanediol, and tricyclodecane dimethanol. Further, a polycarbonate-polyorganosiloxane copolymer obtained by copolymerizing polyorganosiloxane units can also be used.

  The component (G1) may contain two or more kinds of polycarbonates having different dihydric phenol components, polycarbonates containing branched components, various polyester carbonates, polycarbonate-polyorganosiloxane copolymers, and the like. Further, two or more kinds of polycarbonates having different production methods, polycarbonates having different end stoppers, and the like may be contained.

  Reaction methods such as interfacial polymerization, molten transesterification, solid phase transesterification of carbonate prepolymers, and ring-opening polymerization of cyclic carbonate compounds, which are polycarbonate resin production methods, are well known in various documents and patent publications. It is the method that has been.

  The component (G1) may contain not only virgin raw materials but also polycarbonate resins regenerated from used products, so-called material-recycled aromatic polycarbonates. Used products include soundproof walls, glass windows, translucent roofing materials, various glazing materials such as automobile sunroofs, transparent members such as windshields and automobile headlamp lenses, containers such as water bottles, optical recording media, etc. Is preferred. These do not contain a large amount of additives or other resins, and the desired quality is easily obtained stably. In particular, an automotive headlamp lens, an optical recording medium, and the like are preferred as preferred embodiments because they satisfy the more preferable conditions of the viscosity average molecular weight described below. In addition, said virgin raw material is a raw material which is not yet used in the market after the manufacture.

The viscosity average molecular weight of the component (G1) is preferably 1 × 10 ^{4 to} 5 × 10 ⁴ , more preferably 1.4 × 10 ^{4 to} 3 × 10 ⁴ , and still more preferably 1.8 × 10 ^{4 to} 2.5. × 10 ⁴ When the viscosity average molecular weight is in the range of 1.8 × 10 ^{4 to} 2.5 × 10 ⁴ , the polylactic acid resin composition is particularly excellent in both good fluidity and impact resistance of the molded product. Most preferably, the viscosity average molecular weight is in the range of 1.9 × 10 ^{4 to} 2.4 × 10 ⁴ . In addition, this viscosity average molecular weight should just be satisfied as the whole (G1) component, and the whole (G1) component containing 2 or more types of components from which molecular weight differs includes what satisfy | fills this range.

In calculating the viscosity average molecular weight, first, the specific viscosity calculated by the following formula (a) is the Ostwald viscosity for a sample solution prepared by dissolving 0.7 g of the component (G1) at 20 ° C. in 100 ml of methylene chloride. Obtained from the measurement result by the meter. Next, the viscosity average molecular weight M is determined from the specific viscosity obtained using the following formulas (b) to (d).
Specific viscosity (η _SP ) = (t−t ₀ ) / t (a)
[T ₀ is methylene chloride falling seconds, t is sample solution falling seconds]
η _SP /c=[η]+0.45×[η] ² c (where [η] is the intrinsic viscosity) (b)
[Η] = 1.23 × 10 ⁻⁴ M ^0.83 (c)
c = 0.7 (d)
((G2) Core shell rubber)
The component (G) may contain a core shell rubber. The core-shell rubber is a multi-layer polymer having an innermost layer (core layer) made of a polymer and one or more layers (shell layers) made of a polymer different from the core layer covering the core layer. It is.

  The polylactic acid resin composition may contain only one kind of core-shell rubber, or may contain two or more kinds. When the polylactic acid resin composition contains core-shell rubber, the total content is preferably in the range of 3 to 12% by mass.

  An example of the core-shell rubber is Si-containing core-shell rubber. The core-shell rubber containing Si preferably contains at least one of a polyorganosiloxane-containing graft copolymer whose core layer is made of a polymer containing Si and an epoxy-modified silicone / acrylic rubber. In particular, a polyorganosiloxane-containing graft copolymer is preferably contained.

  When the polylactic acid resin composition contains a core-shell rubber containing Si, the content is preferably in the range of 3 to 12% by mass. Within this range, the molded article formed from the polylactic acid resin composition has excellent impact resistance and heat resistance.

  Examples of the core-shell rubber containing Si include polyorganosiloxane-containing graft copolymers and epoxy-modified silicone / acrylic rubber.

  When the polylactic acid resin composition contains a polyorganosiloxane-containing graft copolymer, the flame retardancy and impact resistance of the molded product are particularly improved. When the polylactic acid resin composition contains a polyorganosiloxane-containing graft copolymer, the content is preferably in the range of 3 to 12% by mass.

The polyorganosiloxane-containing graft copolymer is obtained from the following components (X) to (Z);
(X) polyorganosiloxane particles;
(Y) a first vinyl monomer;
(Z) A second vinyl monomer.

(Y) component consists only of the following (Y-1) component, or consists of the following (Y-1) component and (Y-2) component, and contains these components in the following ratio;
(Y-1) 100 to 50% by mass of a polyfunctional monomer;
(Y-2) 0-50 mass% of other copolymerizable monomers.

  In the presence of 40 to 90 parts by mass of the (X) component, the polyorganosiloxane-containing graft copolymer polymerizes 0.5 to 10 parts by mass of the (Y) component, and further 5 to 50 parts by mass of the (Z) component. It is obtained by polymerizing. The amount of each component is a value when the total amount of the components (X) to (Z) is 100 parts by mass.

  Component (X) has a toluene insoluble content (a toluene insoluble content when 0.5 g of (X) component is immersed in 80 ml of toluene at room temperature for 24 hours) of 95% by mass or less, further 50% by mass or less, particularly 20% by mass. % Or less is preferable for improving the flame retardancy and impact resistance of the molded product.

  Specific examples of the component (X) include polydimethylsiloxane particles, polymethylphenylsiloxane particles, dimethylsiloxane-diphenylsiloxane copolymer particles, and the like. These may be used alone or in combination of two or more.

  Part or all of the component (X) may be modified polyorganosiloxane particles containing a polymer other than polyorganosiloxane. Specific examples of the polymer other than polyorganosiloxane include polybutyl acrylate, butyl acrylate-styrene copolymer, and the like. The content of the polymer other than the polyorganosiloxane in the component (X) is preferably low, and the content is particularly preferably 5% by mass or less. In particular, it is preferable for the component (X) to be particles composed essentially of polyorganosiloxane in order to improve the flame retardancy of the molded product.

  The average particle diameter of the component (X) is not particularly limited, but the number average particle diameter obtained from light scattering or electron microscope observation is preferably 0.008 to 0.6 μm, preferably 0.01 to 0.2 μm. It is more preferable if it is 0.01 to 0.15 μm. If the number average particle size is too small, production is difficult. Conversely, if the number average particle size is too large, the flame retardancy of the molded product may not be sufficiently improved. In order to improve the appearance of the molded product, it is preferable that the variation coefficient (100 × standard deviation / number average particle size (%)) of the particle size distribution of the component (X) is in the range of 10 to 100%. More preferably, it is ˜60%.

  (X) Monomers of organosiloxane; homopolymerization of bifunctional silane compound; copolymerization of organosiloxane and bifunctional silane compound; organosiloxane and vinyl polymerizable group-containing silane Copolymerization with a compound; copolymerization of a bifunctional silane compound and a vinyl-based polymerizable group-containing silane compound; organosiloxane, bifunctional silane compound and vinyl-based polymerizable group-containing silane compound, or further, these compounds and trifunctional or more And the like, and the like.

  Among the above compounds, the organosiloxane or the bifunctional silane compound is a component constituting the main skeleton of the polyorganosiloxane chain.

  Examples of the organosiloxane include hexamethylcyclotrisiloxane (a), octamethylcyclotetrasiloxane (b), decamethylcyclopentasiloxane (c), dodecamethylcyclohexasiloxane (d), and tetradecamethylcycloheptasiloxane (e). , Hexadecamethylcyclooctasiloxane (f) and the like.

  Difunctional silane compounds include diethoxydimethylsilane, dimethoxydimethylsilane, diphenyldimethoxysilane, diphenyldiethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, heptadecafluorodecylmethyldimethoxysilane , Trifluoropropylmethyldimethoxysilane, octadecylmethyldimethoxysilane and the like.

  In particular, from the viewpoint of improving economic efficiency and flame retardancy of molded products, (b) component, a mixture of components (a) to (e), or (a) to (a) in the monomer used for the production of component (X) (F) It is preferable that the ratio of the mixture of a component is 70-100 mass%, and it is still more preferable that it is 80-100 mass%. It is preferable that diphenyldimethoxysilane, diphenyldiethoxysilane, etc. occupy 0-30 mass%, and it is still more preferable that the remaining part occupies 0-20 mass%.

  A vinyl-based polymerizable group-containing silane compound is a component for copolymerizing with an organosiloxane, a bifunctional silane compound, a tri- or higher functional silane compound, etc., and introducing a vinyl-based polymerizable group into the side chain or terminal of the copolymer. It is. This vinyl-based polymerizable group acts as a graft active site when chemically bonding to a vinyl-based (co) polymer formed from the (Y) component or the (Z) component described later. Furthermore, this vinyl polymerizable group-containing silane compound can form a crosslink by causing a radical reaction between graft active sites in the presence of a radical polymerization initiator. That is, the vinyl polymerizable group-containing silane compound can also function as a crosslinking agent. As the radical polymerization initiator, the same ones that can be used in graft polymerization described later can be used. Even if the vinyl polymerizable group-containing silane compound is allowed to function as a cross-linking agent, a part of the silane compound remains as a graft active point, so that grafting is possible.

  Specific examples of the vinyl polymerizable group-containing silane compound include γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane, and γ-methacryloyloxypropyldiethoxymethylsilane. (Meth) acryloyloxy group-containing silane compounds such as γ-acryloyloxypropyldimethoxymethylsilane and γ-acryloyloxypropyltrimethoxysilane; vinylphenyl groups such as p-vinylphenyldimethoxymethylsilane and p-vinylphenyltrimethoxysilane -Containing silane compounds; vinyl group-containing silane compounds such as vinylmethyldimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane; mercaptopropylto Silane, and mercapto group-containing silane compounds such as mercaptopropyl dimethoxymethyl silane, and the like.

  Among these, at least one selected from a (meth) acryloyloxy group-containing silane compound, a vinyl group-containing silane compound, and a mercapto group-containing silane compound is preferable from the viewpoint of economy. In addition, when the said vinyl polymerizable group containing silane compound is a trialkoxysilane type | mold, it also has a role of the silane compound more than trifunctional shown below.

  A trifunctional or higher functional silane compound is copolymerized with the organosiloxane, bifunctional silane compound, vinyl polymerizable group-containing silane compound, etc. to introduce a cross-linked structure into the polyorganosiloxane, and the component (X) is a rubber. Elasticity can be imparted. That is, a trifunctional or higher functional silane compound is used as a crosslinking agent for polyorganosiloxane.

  Examples of the trifunctional or higher functional silane compounds include tetraethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, trifluoropropyltrimethyl. Examples thereof include tetrafunctional and trifunctional alkoxysilane compounds such as methoxysilane and octadecyltrimethoxysilane. Among these, it is preferable to use at least one of tetraethoxysilane and methyltriethoxysilane from the viewpoint of high crosslinking efficiency.

  The proportion of the organosiloxane, bifunctional silane compound, vinyl polymerizable group-containing silane compound, and trifunctional or higher functional silane compound used during polymerization is appropriately determined. In particular, the ratio of the total amount of the organosiloxane and the bifunctional silane compound is preferably 50 to 99.9% by mass, and more preferably 60 to 99.5% by mass. In addition, it is preferable that the ratio of organosiloxane and a bifunctional silane compound is 100 / 0-0 / 100 by weight ratio, and if it is 100 / 0-70 / 30, it is still more preferable. The proportion of the vinyl polymerizable group-containing silane compound is preferably 0 to 40% by mass, and more preferably 0.5 to 30% by mass. The proportion of the trifunctional or higher functional silane compound is preferably 0 to 50% by mass, and more preferably 0 to 39% by mass. It is preferable to use at least one of the vinyl-based polymerizable group-containing silane compound and the trifunctional or higher functional silane compound, and particularly the ratio of at least one of the vinyl-based polymerizable group-containing silane compound and the trifunctional or higher functional silane compound is It is preferable to set it as 0.1% or more.

  When the proportion of the organosiloxane and the bifunctional silane compound used is too small, the molded product tends to become brittle. On the other hand, if the amount is too large, the amount of the vinyl polymerizable group-containing silane compound and the tri- or higher functional silane compound is too small, and the effect of using these tends to be difficult to be expressed.

  Further, if the ratio of the vinyl polymerizable group-containing silane compound or the trifunctional or higher functional silane compound is too small, the flame retardancy of the molded product may not be sufficiently improved. On the other hand, if it is too much, the molded product tends to be brittle.

  The component (X) is preferably produced by emulsion polymerization of the above monomer. Emulsion polymerization can be performed, for example, by emulsifying and dispersing the monomer and water in water by mechanical shearing in the presence of an emulsifier to bring them into an acidic state. In this case, when emulsion droplets of several μm or more are prepared by mechanical shearing, the average particle size of the component (X) obtained after polymerization is controlled in the range of 0.02 to 0.6 μm depending on the amount of the emulsifier used. be able to. In addition, the coefficient of variation (100 × standard deviation / average particle size) (%) of the particle size distribution of the component (X) can be controlled in the range of 20 to 70%.

  Moreover, when manufacturing (X) component with a narrow particle diameter distribution at 0.1 micrometer or less, it is preferable to superpose | polymerize in multiple steps. For example, 1 to 20% of an emulsion comprising emulsion droplets of several μm or more obtained by emulsifying the monomer, water and emulsifier by mechanical shearing was first obtained by emulsion polymerization in an acidic state (X) Polymerize by adding the remaining emulsion in the presence of the ingredients as seeds. The component (X) thus obtained can be controlled to have an average particle size of 0.02 to 0.1 μm and a variation coefficient of particle size distribution of 10 to 60% depending on the amount of the emulsifier. A more preferable method is that, in the multistage polymerization, instead of the seed of the component (X), a vinyl monomer (for example, styrene, butyl acrylate, methyl methacrylate, etc.) used at the time of graft polymerization described later is obtained by a usual emulsion polymerization method. The same multistage polymerization is carried out using a vinyl (co) polymer formed by (co) polymerization. In this case, the average particle size of the resulting polyorganosiloxane (modified polyorganosiloxane) particles can be controlled to 0.008 to 0.1 μm and the coefficient of variation in particle size distribution to 10 to 50% depending on the amount of emulsifier. The emulsified droplets of several μm or more can be prepared by using a high-speed stirrer such as a homomixer.

  In the emulsion polymerization, an emulsifier that does not lose emulsification ability under an acidic state is used. Specific examples include alkylbenzene sulfonic acid, sodium alkylbenzene sulfonate, alkyl sulfonic acid, sodium alkyl sulfonate, sodium (di) alkyl sulfosuccinate, sodium polyoxyethylene nonylphenyl ether sulfonate, sodium alkyl sulfate, and the like. These may be used alone or in combination of two or more. In particular, it is preferable to use at least one selected from alkylbenzene sulfonic acid, sodium alkylbenzene sulfonate, alkyl sulfonic acid, sodium alkyl sulfonate, and sodium (di) alkyl sulfosuccinate since the emulsion stability is relatively high. Furthermore, alkylbenzenesulfonic acid and alkylsulfonic acid are particularly preferable because they also act as a polymerization catalyst for the monomer.

  The acidic state of the reaction system is achieved by adding an inorganic acid such as sulfuric acid or hydrochloric acid or an organic acid such as alkylbenzene sulfonic acid, alkyl sulfonic acid, or trifluoroacetic acid to the reaction system. The pH of the reaction system is preferably adjusted to 1 to 3, more preferably 1.0 to 2.5 in consideration of corrosion inhibition of production equipment and achievement of an appropriate polymerization rate. The heating for the polymerization is preferably 60 to 120 ° C., more preferably 70 to 100 ° C. in order to achieve an appropriate polymerization rate.

  In an acidic state, the Si—O—Si bond forming the polyorganosiloxane skeleton is in an equilibrium state of cleavage and generation, and this equilibrium changes with temperature. For this reason, in order to stabilize the polyorganosiloxane chain, it is preferable to neutralize the reaction system by adding an alkaline aqueous solution such as sodium hydroxide, potassium hydroxide or sodium carbonate. Further, the equilibrium becomes closer to the production side as the temperature becomes lower, and a product having a high molecular weight or a high degree of crosslinking is easily obtained. For this reason, in order to obtain a product having a high molecular weight or a high degree of crosslinking, the polymerization of the monomer is allowed to proceed at 60 ° C. or higher, and then the reaction system is cooled to room temperature or lower and maintained for about 5 to 100 hours before neutralization. It is preferable to do.

  The component (X) obtained in this way is, for example, an organosiloxane or a bifunctional silane compound, and when a vinyl-based polymerizable group-containing silane compound is added and polymerized, they are usually randomly copolymerized. Thus, a polymer having a vinyl polymerizable group is obtained. In addition, when a trifunctional or higher functional silane compound is copolymerized, it has a crosslinked network structure. In addition, when the vinyl polymerizable groups are cross-linked by radical reaction with a radical polymerization initiator as used at the time of graft polymerization, which will be described later, it has a cross-linked structure in which the vinyl polymerizable groups are chemically bonded. The unreacted vinyl polymerizable group remains.

  (Y) component consists of (Y-1) component, or consists of (Y-1) component and (Y-2) component. The (Y-1) component is a polyfunctional monomer containing two or more polymerizable unsaturated bonds in the molecule, and the ratio in the (Y) component is 100 to 50% by mass. (Y-2) component is vinyl monomers other than (Y-1) component, and the ratio in (Y) component is 0-50 mass%. Use of the component (Y) contributes to improvement of flame retardancy and impact resistance of the molded product.

  The ratio of the component (Y-1) in the component (Y) is 50% by mass or more, and the ratio of the component (Y-2) in the component (Y) is 50% by mass or less. Impact properties are further improved. The ratio of the (Y-1) component in the (Y) component is particularly preferably 100 to 80% by mass, and more preferably 100 to 90% by mass. The proportion of the component (Y-2) in the component (Y) is particularly preferably 0 to 20% by mass, and more preferably 0 to 10% by mass.

  Examples of the component (Y-1) include allyl methacrylate, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, and divinylbenzene. These may be used alone or in combination of two or more. Among these, the use of allyl methacrylate is particularly preferred from the viewpoint of economy and effects.

  As component (Y-2), aromatic vinyl monomers such as styrene, α-methylstyrene, paramethylstyrene and parabutylstyrene; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; acrylic acid Methyl, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, glycidyl acrylate, hydroxyethyl acrylate, hydroxybutyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, lauryl methacrylate (Meth) acrylic acid ester monomers such as glycidyl methacrylate and hydroxyethyl methacrylate; carboxyl group-containing vinyl monomers such as itaconic acid, (meth) acrylic acid, fumaric acid and maleic acid . These may be used alone or in combination of two or more.

  The component (Z) ensures compatibility between the polyorganosiloxane-containing graft copolymer and the components (A) and (H), and contributes to improving the dispersibility of the polyorganosiloxane-containing graft copolymer.

  As (Z) component, the same thing as said (Y-2) component, such as methyl methacrylate, butyl methacrylate, styrene, acrylonitrile, can be used. These may be used alone or in combination of two or more.

The solubility parameter of the component (Z) is preferably 9.15 to 10.15 [(cal / cm ³ ) ^1/2 ], and 9.17 to 10.10 [(cal / cm ³ ) ^1/2 ], More preferably 9.20 to 10.05 [(cal / cm ³ ) ^1/2 ]. By setting the solubility parameter within the above range, the flame retardancy of the molded product can be further improved. The solubility parameter is a value calculated by using the group parameter of Small in the group contribution method described in “Polymer Handbook”, 1999, 4th edition, pages 682 to 685, published by John Wiley & Son, Inc.).

  In the presence of 40 to 90 parts by mass of the (X) component, the polyorganosiloxane-containing graft copolymer polymerizes 0.5 to 10 parts by mass of the (Y) component, and further 5 to 50 parts by mass of the (Z) component. It is obtained by polymerizing. The amount of each component is a value when the total amount of the components (X) to (Z) is 100 parts by mass. In particular, the proportion of the component (X) is preferably 60 to 80 parts by mass, and more preferably 60 to 75 parts by mass. The proportion of the component (Y) is preferably 1 to 5 parts by mass, and more preferably 2 to 4 parts by mass. The proportion of component (Z) is preferably 15 to 39 parts by mass, more preferably 21 to 38 parts by mass.

  When the proportion of the component (X) is too small or too large, the flame retarding effect of the molded product is low. When the component (Y) is too small, the flame retardancy effect and impact resistance improving effect of the molded product are lowered, and when it is too much, the impact resistance improving effect of the molded product is lowered. (Z) When there are too few components and there are too many components, the flame-retardant effect of a molded article will become low.

  The polyorganosiloxane-containing graft copolymer can be produced by a known seed emulsion polymerization. For example, radical polymerization of the (Y) component can be performed in the latex of the (X) component, and further, radical polymerization of the (Z) component can be performed. Both the component (Y) and the component (Z) may be polymerized in one stage or may be polymerized in two or more stages.

  In the radical polymerization, an appropriate method such as a method of causing the reaction to proceed by thermally decomposing a radical polymerization initiator or a reaction in a redox system using a reducing agent can be employed. The reaction temperature during the polymerization is preferably 30 to 120 ° C.

  As radical polymerization initiators, cumene hydroperoxide, t-butyl hydroperoxide, benzoyl peroxide, t-butyl peroxyisopropyl carbonate, di-t-butyl peroxide, t-butyl peroxide are used because of their high reactivity. It is preferable to use organic peroxides such as oxylaurate, lauroyl peroxide, succinic acid peroxide, cyclohexanenon peroxide, and acetylacetone peroxide; inorganic peroxides such as potassium persulfate and ammonium persulfate. The amount of the radical polymerization initiator used is 0.005 to 20 parts, further 0.01 to 10 parts, particularly 0.03 to 5 parts, with respect to 100 parts of the (Y) component or the (Z) component. Preferably there is.

  On the other hand, as the reducing agent used in the redox system, ferrous sulfate / glucose / sodium pyrophosphate, ferrous sulfate / dextrose / sodium pyrophosphate, ferrous sulfate / sodium formaldehyde sulfoxylate / ethylenediamine acetate, etc. And the like.

  A chain transfer agent may be used in the radical polymerization. Specific examples of the chain transfer agent include t-dodecyl mercaptan, n-octyl mercaptan, n-tetradecyl mercaptan, n-hexyl mercaptan and the like. When the chain transfer agent is used, the amount used is preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of the component (Y) or the component (Z).

  In the polymerization, when the (X) component contains a vinyl polymerizable group, the (Y) component reacts with the vinyl polymerizable group of the (X) component when polymerized by the radical polymerization initiator. A graft is formed. When there is no vinyl polymerizable group in the component (X), a specific radical initiator such as t-butyl peroxylaurate is used to extract hydrogen from an organic group such as a methyl group bonded to a silicon atom. The radical (Y) is polymerized by the radicals formed to form a graft. Further, when the (Z) component is polymerized by the radical polymerization initiator, it not only reacts with the (X) component in the same manner as the (Y) component, but also exists in the polymer formed by the (Y) component. The graft by the (Z) component is formed by reacting with the saturated bond.

  The polyorganosiloxane-containing graft copolymer obtained by emulsion polymerization or the like may be used by separating the polymer from the latex, or may be used as it is. Examples of the method for separating the polymer include a usual method, for example, a method of coagulating, separating, washing, dehydrating and drying the latex by adding a metal salt such as calcium chloride, magnesium chloride, magnesium sulfate to the latex. . A spray drying method can also be used.

  In the polymerization of the (Y) component and the (Z) component in the presence of the (X) component, the portion corresponding to the branch of the graft copolymer (here, the polymer of the (Y) component and the (Z) component) A so-called free polymer obtained by polymerizing only the branch component alone without grafting to the trunk component (component (X) here) is also produced as a by-product, and obtained as a mixture of the polyorganosiloxane-containing graft copolymer and the free polymer. . Both of these are referred to as a polyorganosiloxane-containing graft copolymer.

  In the polyorganosiloxane-containing graft copolymer, the (Y) component is grafted to the (X) component, and the (Z) component is also grafted to the polymer formed by the (Y) component as well as the (X) component. Due to the structure, the amount of free polymer is reduced. Acetone insoluble content of this polyorganosiloxane-containing graft copolymer (acetone insoluble content when 1 g of polyorganosiloxane-containing graft copolymer is immersed in 80 ml of acetone at room temperature for 48 hours) is 80% or more, and more than 85% It is preferable for improving the flame retardancy of the molded product.

  Such polyorganosiloxane-containing graft copolymers are available as commercial products, and examples thereof include trade names Kane Ace MR01 and Kane Ace MR02 manufactured by Kaneka Corporation.

  When the polylactic acid resin composition contains an epoxy-modified silicone / acrylic rubber, the content is preferably in the range of 3 to 12% by mass.

  As the epoxy-modified silicone / acrylic rubber, a polymer of alkyl acrylate, silyl group-terminated polyether, and glycidyl group-containing vinyl compound can be used. This epoxy-modified silicone / acrylic rubber is a composite of a copolymer of an alkyl acrylate and a silyl group-terminated polyether (silicone acrylic composite rubber) and a polymer of a glycidyl group-containing vinyl compound such as glycidyl methacrylate. May be. In this case, all or part of the copolymer of alkyl acrylate and silyl group-terminated polyether and the polymer of the glycidyl group-containing vinyl compound may be copolymerized.

  The core layer of the epoxy-modified silicone / acrylic rubber is composed of a copolymer of an alkyl acrylate and a silyl group-terminated polyether, and the shell layer is composed of a polymer of a glycidyl group-containing vinyl compound. The multilayer structure polymer can be obtained, for example, by adding a glycidyl group-containing vinyl compound to a latex of a copolymer of an alkyl acrylate and a silyl group-terminated polyether and graft polymerization.

  The structural formula of a typical example of a copolymer (silicone acrylic composite rubber) of an alkyl acrylate and a silyl group-terminated polyether is shown in [Chemical Formula 3] below. The left part of this structural formula is an alkyl acrylate unit derived from an alkyl acrylate, and the right part is a silyl group-terminated polyether unit derived from a silyl group-terminated polyether.

  A structural example of a typical example of a glycidyl group-containing vinyl compound is shown in [Chemical Formula 4] below.

  Specific examples of the alkyl acrylate include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, and methacrylate. 2-ethylhexyl acrylate; cyclohexyl methacrylate, stearyl methacrylate, octadecyl methacrylate, phenyl methacrylate, benzyl methacrylate, chloromethyl methacrylate, 2-chloroethyl methacrylate, 2-hydroxy methacrylate Ethyl; 3-hydroxypropyl methacrylate, 2,3,4,5,6-pentahydroxyhexyl methacrylate, 2,3,4,5-tetrahydroxypentyl methacrylate, aminoethyl acrylate, propyl acrylate Aminoethyl; Acrylic acid dimethylaminoethyl methacrylate ethyl aminopropyl, and the like phenyl methacrylate aminoethyl or cyclohexyl aminoethyl methacrylate. These compounds can be used alone or in combination of two or more.

  As the silyl group-terminated polyether, a polyether such as polyethylene or polypropylene having a silyl group at the terminal is used. Specific examples of the silyl group include halogens such as alkylsilyl groups such as methylsilyl group, ethylsilyl group, propylsilyl group, and butylsilyl group, 3-chloropropylsilyl group, and 3,3,3-trifluoropropylsilyl group. Alkylsilyl groups such as alkylsilyl groups, vinylsilyl groups, allylsilyl groups, butenylsilyl groups, arylsilyl groups such as phenylsilyl groups, tolylsilyl groups, naphthylsilyl groups, cycloalkylsilyl groups such as cyclopentylsilyl groups, cyclohexylsilyl groups, benzyl Examples thereof include aryl-alkylsilyl groups such as silyl group and phenethylsilyl group. Such silyl group-terminated polyethers may be used alone or in combination of two or more.

  Examples of the glycidyl group-containing vinyl compound include glycidyl methacrylate, glycidyl itaconate, diglycidyl itaconate, allyl glycidyl ether, styrene-4-glycidyl ether, and 4-glycidyl styrene. These compounds can be used alone or in combination of two or more.

  As such an epoxy-modified silicone / acrylic rubber, commercially available products can be appropriately used. As a specific example, there can be mentioned a trade name Metabrene S2200 manufactured by Mitsubishi Rayon Co., Ltd., which is a core-shell structure containing glycidyl methacrylate in the shell.

  The polylactic acid resin composition may contain core-shell rubber other than Si-containing core-shell rubber, that is, core-shell rubber not containing Si. Examples of the core-shell rubber not containing Si include an unsaturated carboxylic acid alkyl ester-diene rubber-aromatic vinyl graft copolymer.

  By incorporating an unsaturated carboxylic acid alkyl ester-diene rubber-aromatic vinyl graft copolymer into the polylactic acid resin composition, a part of the function of the core-shell rubber containing Si is unsaturated carboxylic acid alkyl ester-diene. It can be replaced with a rubber-aromatic vinyl graft copolymer. In this case, the cost is advantageous.

  The unsaturated carboxylic acid alkyl ester used to obtain the unsaturated carboxylic acid alkyl ester-diene rubber-aromatic vinyl graft copolymer includes methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate. Etc. Examples of the diene rubber component include rubbers having a glass transition point of 10 ° C. or less, such as polybutadiene, styrene-butadiene copolymer, and acrylonitrile-butadiene. Examples of the aromatic vinyl include nuclei substituted styrene such as styrene, α-methylstyrene and p-methylstyrene. These unsaturated carboxylic acid alkyl esters, diene rubbers, and aromatic vinyls can be used alone or in combination of two or more.

  A representative example of the unsaturated carboxylic acid alkyl ester-diene rubber-aromatic vinyl graft copolymer is a methyl methacrylate-butadiene-styrene copolymer (MBS resin). The methyl methacrylate-butadiene-styrene copolymer is preferably a multilayer structure polymer including a core layer composed of a butadiene / styrene polymer and a shell layer composed of a methyl methacrylate polymer.

  The structural formula of the butadiene / styrene polymer is shown in the following [Chemical Formula 5]. The left part of this structural formula is a butadiene unit derived from butadiene, and the right part is a styrene unit derived from styrene.

  The structural formula of the methacrylic polymer constituting the shell layer is shown in the following [Chemical Formula 6].

  Examples of the method for producing the unsaturated carboxylic acid alkyl ester-diene rubber-aromatic vinyl graft copolymer include various methods such as bulk polymerization, suspension polymerization, and emulsion polymerization. In particular, the emulsion polymerization method is suitable. The core-shell type graft rubber-like elastic body thus obtained preferably contains 50% by mass or more of the diene rubber component.

  As such a methyl methacrylate-butadiene-styrene copolymer, a commercially available product can be appropriately used. Preferred examples thereof include trade names Metabrene C-223A, Metabrene C-323A, Metabrene C-215A, Metabrene C-201A, Metabrene C-202, Metabrene C-102, and Metabrene C-140A manufactured by Mitsubishi Rayon Co., Ltd. , Metabrene C-132, etc., trade name Kane Ace M-600 manufactured by Kaneka Co., Ltd., trade name Paraloid EXL-2638 manufactured by Rohm and Haas Co., Ltd. and the like.

((G3) Copolymer having glycidyl group)
The polylactic acid resin composition contains at least one copolymer selected from an acrylic polymer having a glycidyl group and an acrylic-styrene copolymer having a glycidyl group as at least a part of the component (G). May be. In this case, the fluidity of the polylactic acid resin composition can be further improved, and the impact resistance value of the molded product can be further improved. The total content of the acrylic polymer having a glycidyl group and the acrylic-styrene copolymer having a glycidyl group in the polylactic acid resin composition is preferably in the range of 1 to 5% by mass. If this content is too large, the viscosity may increase, or conversely, it may act as a plasticizer.

  As the acrylic polymer having a glycidyl group, a copolymer of (meth) acrylic acid ester monomers having a glycidyl group, a (meth) acrylic acid ester monomer having a glycidyl group and a (meth) acrylic acid ester Copolymers of monomers, copolymers of acrylate monomers having glycidyl groups, copolymers of acrylate monomers having glycidyl groups and acrylate monomers, having glycidyl groups Examples include a copolymer of a (meth) acrylic acid ester monomer and an acrylic acid ester monomer, a copolymer of an acrylic acid ester monomer having a glycidyl group and a (meth) acrylic acid ester monomer, and the like.

  Examples of the acryl-styrene copolymer having a glycidyl group include a copolymer of a styrene monomer and a (meth) acrylate monomer having a glycidyl group, and an acrylate monomer having a styrene monomer and a glycidyl group. And a copolymer of a monomer. Specific examples of the acryl-styrene copolymer having a glycidyl group include ARUFON UG-4000 series manufactured by Toagosei Co., Ltd.

  The production method of the acrylic polymer having a glycidyl group and the acrylic-styrene copolymer having a glycidyl group is not particularly limited. For example, a method of polymerizing an acrylic ester monomer having a glycidyl group; a method of copolymerizing an acrylic ester monomer having a glycidyl group with styrene; a method of polymerizing a monomer such as acrylic acid having no glycidyl group; an acrylic acid having no glycidyl group Examples thereof include a method of copolymerizing a monomer such as styrene with styrene and then adding an alcohol having a glycidyl group to a carboxyl group of an acrylic acid unit by a condensation reaction. Examples of the acrylic monomer having a glycidyl group include glycidyl methacrylate and glycidyl acrylate.

(Other thermoplastic resins)
The component (G) may contain various thermoplastic resins other than those described above. For example, in a polylactic acid resin composition, polyethylene terephthalate resin (PET resin), polybutylene terephthalate resin (PBT resin), cyclohexanedimethanol copolymerized polyethylene terephthalate resin (so-called PET-G resin), polyethylene naphthalate resin, polybutylene Aromatic polyester resins such as phthalate resins; polymethyl methacrylate resins (PMMA resins); cyclic polyolefin resins; polycaprolactone resins; thermoplastic fluororesins represented by polyvinylidene fluoride resins; polyethylene resins and ethylene- (α-olefin) Polymer resin, polypropylene resin, propylene- (α-olefin) copolymer resin and the like can be contained. The polylactic acid resin composition may contain only one kind of resin as described above, or may contain two or more kinds. Such various thermoplastic resins can further improve the impact resistance of the molded product. The content of these thermoplastic resins is preferably in the range of 3 to 12% by mass with respect to the polylactic acid resin composition.

[Other ingredients]
The polylactic acid resin composition may contain crystal nucleating agents, stabilizers, pigments, dyes, reinforcing agents (mica, clay, glass fiber, etc.), colorants, ultraviolet absorbers, antioxidants, lubricants, if necessary. You may contain well-known additives, such as a mold release agent, a plasticizer, an antistatic agent, and an inorganic and organic type antibacterial agent. These components may be added at the time of kneading the polylactic acid resin composition, or may be added at the time of molding or the like.

[Production of polylactic acid resin composition and molded product]
The polylactic acid resin composition is prepared by mixing and kneading the above components. The polylactic acid resin composition may be formed into pellets as necessary. In the mixing and kneading, for example, a twin screw extruder, a Banbury mixer, a heating roll, or the like is used. In particular, melt kneading with a twin screw extruder is preferred. In mixing and kneading, a resin and other additives may be blended by side feed or the like, if necessary.

  Various molded articles are obtained by molding the polylactic acid resin composition by an appropriate molding method such as injection molding, blow molding, sheet molding, or vacuum molding.

  Since the molded product thus obtained has high hydrolysis resistance and excellent rigidity, it can be used in a wide range of fields such as the home appliance field, building materials, and sanitary field that are expected to be used for a long period of time.

  For example, since this polylactic acid resin composition has a short molding cycle and has molding processability and characteristics equivalent to those of conventional ABS resins, it can be used for casings for electronic devices such as exteriors of desktop holders for mobile phones, and for mobile phones. It is suitably used for producing internal parts for electronic equipment such as internal chassis parts.

[Production example]
To 100 parts by weight of D-lactide (manufactured by Musashino Chemical Laboratory, Inc., optical purity 99% or more), 0.006 part by weight of octylate and 0.37 part by weight of octadecyl alcohol are added. The reaction was carried out at 190 ° C. for 2 hours in a connected reactor, after which 0.01 parts by weight of a transesterification inhibitor (dihexylphosphonoethyl acetate DHPA) was added, and the remaining lactide was removed by reducing the pressure, To obtain poly-D-lactic acid. The obtained poly-D-lactic acid had a weight average molecular weight of 130,000, a glass transition point (Tg) of 60 ° C., and a melting point of 170 ° C.

  This poly-D-lactic acid and poly-L-lactic acid (4042D manufactured by Nature Works, optical purity of 95% or more, melting point 150 ° C., weight average molecular weight 210,000) and a twin screw extruder of 32 mm diameter (manufactured by Coperion) , ZSK 32) was used for melt-kneading under conditions of a cylinder temperature of 200 ° C. to 250 ° C. and a rotation speed of 200 rpm to obtain stereocomplex polylactic acid. The resulting stereocomplex polylactic acid had a melting point of 213 ° C. and a stereogenicity of 100%.

[Examples 1 to 29, Comparative Examples 1 to 5]
For each Example and Comparative Example, the components shown in Tables 1 and 2 were used, and the resin components were dried in advance, and then these components were mixed with a tumbler for 10 minutes. The obtained mixture was extruded with a twin-screw extruder under conditions of a die vicinity temperature of 190 ° C. and an inlet vicinity temperature of 200 ° C. to obtain a strand. In addition, about the compounding quantity of antioxidant among the compounding quantities of the components shown in Tables 1 and 2, the ratio (ppm) based on mass with respect to the total quantity of all components is shown. Tables 1 and 2 also show the volume ratio (% by volume) with respect to the total of the resin components (polylactic acid, ABS resin, PMMA, core shell rubber, and polycarbonate resin) with respect to the blending amount of the ABS resin.

  The strand was quickly cooled in a cooling tank and then cut with a cutter to obtain a pellet-shaped resin composition having a length of 2 to 4 mm.

  The resin composition was dried by heating at 120 ° C. for 4 hours in a dehumidifying dryer, and then a 100-ton injection molding machine and an ISO-compliant test piece mold (color plate, 60 mm × 60 mm × 2 mm, 2 The cylinder temperature was set to 230 ° C. near the head and 220 ° C. near the material inlet, and the mold temperature was set to 110 ° C., and injection molding was performed to obtain a molded product.

  However, when polylactic acid C is used, in the above method, the temperature near the die and the temperature near the inlet in the twin-screw extruder are set to 225 ° C., and the cylinder temperature is 230 ° C. near the head at the time of injection molding, near the material inlet. At 230 ° C.

  For Examples 13 and 14, before mixing all the raw material components, a carbodiimide compound was first mixed with polylactic acid to prepare a master batch having a carbodiimide compound content of 10 mass%.

[Processability evaluation]
The melt flow index of the molded product obtained in each example and comparative example was measured according to ISO 1133 under conditions of a temperature of 220 ° C. and a load of 10 kg.

[Molding cycle evaluation]
For each example and comparative example, a single-point gate mold was used during the injection molding of the resin composition, and the dimensions of the molded product were 60 mm × 60 mm × 1 mm. In this case, after the injection of the resin composition into the mold, the holding time (cooling time) required until the molded product can be taken out from the mold without deformation is measured, and this is measured in the molding cycle. It was used as an index.

[Appearance evaluation]
For each example and comparative example, a two-point gate mold was used during the injection molding of the resin composition, and the dimensions of the molded product were 60 mm × 60 mm × 1 mm. In this case, the presence or absence of welds at the center of the molded product was confirmed. In each example and comparative example, 100 samples were tested, and the number of samples in which weld was recognized was evaluated.

[Thermal stability]
In each Example, in order to obtain a molded product, injection molding was continuously performed for 200 shots. In this case, the number of molded products in which dirt was observed on the surface was confirmed, and this was used as an index of thermal stability.

[Color development evaluation]
In each example, carbon black (carbon black MA600B manufactured by Mitsubishi Chemical Corporation) was blended at a rate of 1 part by mass with respect to 100 parts by mass of the total amount of raw material components shown in Tables 1 and 2 when the resin composition was prepared. did.

The resin composition containing the carbon black was molded by an injection molding machine to obtain a molded product having a size of 90 mm × 150 mm × 3 mm. The L ^* value of the surface of the molded product was measured using a spectrophotometer (Murakami Color Research Laboratory).

As a result, the case where the L ^* value was 10 or less was evaluated as ◯, the case where the L ^* value was 11 to 15 was evaluated as Δ, and the case where 16 or less was evaluated as ×.

[Impact resistance evaluation]
The notched Charpy impact value of the molded product obtained in each example was measured according to ISO 179.

[Heat resistance evaluation]
The deflection temperature under load of the molded product in each example was measured according to ISO 75-1 and 75-2. The measurement load was 0.45 MPa.

[Durability evaluation]
After the molded product obtained in each example was exposed to an atmosphere of 60 ° C. and 95% RH, the tensile strength of the molded product was measured according to ISO 179. By performing this test with varying exposure times, the shortest exposure time at which the tensile strength of the molded article after exposure reaches 90% or less of the tensile strength of the molded article before exposure is identified and this is determined as the durability. It was used as an index.

[Dimensional stability evaluation]
The molded product obtained in each example was subjected to a treatment for 48 hours in an atmosphere at 80 ° C., and then the dimensional change of the molded product was measured. From the dimension (a) of the molded product before the treatment and the dimension (b) of the molded product after the treatment, the molding shrinkage rate was calculated by the following formula.

{(B−a) / b} × 100 (%)
[Evaluation results]
The results of the above evaluation tests are shown in Tables 1 and 2 below together with the blending compositions in each Example and Comparative Example.

Details of each component shown in Tables 1 and 2 are as follows.
Polylactic acid A: Poly-L-lactic acid resin (product number Ingeo 3001D manufactured by Nature Works).
Polylactic acid B: Poly-L-lactic acid resin (product number Ingeo 4032D manufactured by Nature Works).
Polylactic acid C: Stereocomplex polylactic acid obtained in the production example.
ABS resin A: acrylonitrile unit ratio 15.4% by mass, styrene unit ratio 71.2% by mass, butylene unit ratio 13.4% by mass, synthetic product by bulk polymerization, average particle size 0.40 μm.
ABS resin B: acrylonitrile unit ratio 20.2% by mass, styrene unit ratio 65.8% by mass, butylene unit ratio 14.0% by mass, synthetic product by bulk polymerization, average particle size 0.86 μm.
ABS resin C: acrylonitrile unit ratio 22.8% by mass, styrene unit ratio 62.2% by mass, butylene unit ratio 15.0% by mass, synthetic product by emulsion polymerization, average particle size 0.40 μm.
ABS resin D: acrylonitrile unit ratio 20.5% by mass, styrene unit ratio 69.0% by mass, butylene unit ratio 10.5% by mass, synthetic product by bulk polymerization, average particle size 0.46 μm.
ABS resin E: acrylonitrile unit ratio 2.0 mass%, styrene unit ratio 34.5 mass%, butylene unit ratio 13.5 mass%, methyl methacrylate unit ratio 50.0 mass%, transparent synthetic product by bulk polymerization, Average particle size 0.40 μm.
ABS resin F: acrylonitrile unit ratio 25.0% by mass, styrene unit ratio 62.3% by mass, butylene unit ratio 12.7% by mass, transparent synthetic product by emulsion polymerization, average particle size 0.3 μm and 0.8 μm Mixture of.
ABS resin G: Acrylonitrile unit ratio 23.4% by mass, styrene unit ratio 56.6% by mass, butylene unit ratio 20.0% by mass, synthetic product by emulsion polymerization, mixture of average particle diameters 0.3 μm and 0.8 μm .
PMMA (High Impact): Charpy impact value with notch 5.6 kJ / m ² specified by Sumitomo Chemical Co., Ltd., trade name Sumipex HT01X, JIS K7111.
PMMA (standard): Sumitomo Chemical Co., Ltd., trade name Sumipex MG-SS, Charpy impact value with notch as defined in JIS K7111, 1.3 kJ / m ² .
Carbodiimide compound: trade name Carbodilite LA-1 manufactured by Nisshinbo Chemical Co., Ltd.
Antioxidant A: AO-2246 (2,2-methylenebis- (4-methyl-6-tert-butylphenol)).
Antioxidant B: trade name Irganox 1076 (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propanoate octadecyl) manufactured by Ciba Geigy.
Antioxidant C: Trade name Wingstay-L (bis (3-t-butyl-4-hydroxy-5-methyl-phenyl) dicyclopentadiene) manufactured by Eriochem.
Core shell rubber A: a trade name of METABRENE S2200 manufactured by Mitsubishi Rayon Co., Ltd., a composite of glycidyl methacrylate and silicone acrylic composite rubber.
-Core shell rubber B: Trade name Metabrene C223A manufactured by Mitsubishi Rayon Co., Ltd., methyl methacrylate / butadiene / styrene copolymer rubber.
Polycarbonate resin: Trade name Iupilon H4000 manufactured by Mitsubishi Engineering Plastics Co., Ltd.
-Talc: Trade name Talc micron white manufactured by Hayashi Kasei Co., Ltd., average particle size 2.8 μm.
Zinc phosphinate: Zinc phenylphosphinate (trade name Eco Promote NP, average particle size 1.5 μm, manufactured by Nissan Chemical Industries, Ltd.).

Claims (11)

A polylactic acid resin composition containing the following components (A) to (C);
(A) polylactic acid;
(B) A PMMA resin having a notched Charpy impact value specified in JIS K7111 of 5 kJ / m ² or more;
(C) ABS resin having a styrene unit ratio of 72% by mass or less and a butadiene unit ratio of 10 to 16% by mass. Furthermore, the polylactic acid resin composition of Claim 1 containing the following (D) component;
(D) A carbodiimide compound. Furthermore, the polylactic acid resin composition of Claim 1 or 2 containing the following (E) component;
(E) 2,2-methylenebis- (4-methyl-6-tert-butylphenol), octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propanoate, bis (3-tert-butyl) Antioxidants selected from -4-hydroxy-5-methyl-phenyl) dicyclopentadiene.   The polylactic acid resin composition according to any one of claims 1 to 3, wherein the component (A) contains at least one selected from poly-L-lactic acid and stereocomplex polylactic acid.   The content of the component (A) is in the range of 20 to 45 mass%, the content of the component (B) is in the range of 2 to 17 mass%, and the content of the component (C) is 45 mass% or more. Item 5. The polylactic acid resin composition according to any one of Items 1 to 4. Furthermore, the polylactic acid resin composition as described in any one of Claims 1 thru | or 5 containing the following (F) component;
(F) A compound that promotes crystallization of polylactic acid.   A molded article formed from the polylactic acid resin composition according to any one of claims 1 to 6.   A desktop holder for a mobile phone formed from the polylactic acid resin composition according to any one of claims 1 to 6.   An internal chassis component of a mobile phone formed from the polylactic acid resin composition according to any one of claims 1 to 6.   The housing | casing for electronic devices formed from the polylactic acid resin composition as described in any one of Claims 1 thru | or 6.   The internal component for electronic devices formed from the polylactic acid resin composition as described in any one of Claims 1 thru | or 6.