JP2015042735A - Polylactic acid-based resin composition and molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polylactic acid-based resin composition which is excellent in heat resistance, impact resistance and humidity-and-heat durability although being a resin composition using a polylactic acid resin.SOLUTION: A polylactic acid-based resin composition comprises a polylactic acid resin (A) having a content of the D body of 0-2.0 mol% or 98.0-100 mol% and a polycarbonate resin (B), in a mass ratio of the polylactic acid resin (A) to the polycarbonate resin (B) of 20/80 to 80/20, and tin oxide (C), in a ratio of 0.005-10 pts.mass to 100 pts.mass of the total of the polylactic acid resin (A) and the polycarbonate resin (B).

Description

  The present invention relates to a polylactic acid-based resin composition containing a polylactic acid resin and a polycarbonate resin whose D-form content satisfies a specific range as main components and containing tin oxide, and a molded body comprising the resin composition. is there.

  In recent years, aliphatic polyesters having features such as biodegradability and plant origin are attracting attention from the viewpoint of reducing environmental impact. Among aliphatic polyesters, polylactic acid resin is notable for its low mechanical cost because it has excellent mechanical properties and can be mass-produced using starch and corn as raw materials. Furthermore, the polylactic acid resin foam foamed with a foaming agent is a cushioning material and packaging material similar to conventional foamed moldings derived from petroleum raw materials, taking advantage of its light weight, cushioning properties, sound deadening properties, heat insulation properties, etc. It can also be used for silencer and building materials.

  However, the polylactic acid resin has a drawback of low hydrolysis resistance and durability during long-term use. This tendency is particularly remarkable under high temperature and high humidity. The hydrolysis reaction of the polylactic acid resin proceeds using the carboxyl group at the end of the molecular chain as a catalyst, and particularly at high temperatures and high humidity, it proceeds at an accelerated rate. For this reason, when a molded product made of a single polylactic acid resin is used for a long period of time, degradation due to hydrolysis, a decrease in strength, a decrease in molecular weight, and the like occur, and there is a problem that it cannot be used practically.

  For this reason, it has come to be thought that it is difficult to spread single use of a polylactic acid resin. On the other hand, even if it is a mixture with other non-degradable resins, the use of polylactic acid resin reduces the use of petroleum-derived resins, which is favorable for the environment because it can contribute to the saving of petroleum resources. The idea of “and” has been infiltrated.

  Then, examination which combines the resin excellent in heat resistance and impact resistance, such as polycarbonate resin, and aliphatic polyester resin is made | formed. Patent Document 1 discloses a resin composition comprising a polylactic acid resin and an aromatic polycarbonate resin. In terms of heat resistance and impact resistance, this resin composition is improved to a practical level as compared with the case where a polylactic acid resin is used alone.

  Patent Document 2 describes a resin composition in which an impact modifier such as a core-shell type graft polymer is blended with a resin composition composed of a polycarbonate resin and a polylactic acid resin. The impact property could be improved.

  However, in both resin compositions, the disadvantage that the polylactic acid resin has low hydrolysis resistance and durability during long-term use (hereinafter sometimes referred to as wet heat durability) has not been solved. For this reason, the wet heat durability of the resin composition itself is low, and it is difficult to use it under high temperature and high humidity, and there is a problem that the application is limited.

JP-A-7-109413 JP-A-2005-48067

  The present invention solves the above-mentioned problems, and is a resin composition using a polylactic acid resin, yet has heat resistance, impact resistance, hydrolysis resistance and durability during long-term use (hereinafter referred to as wet heat durability). It is a technical problem to provide a polylactic acid-based resin composition excellent in (sometimes referred to as property).

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems. That is, the gist of the present invention is as follows.
(1) A resin composition comprising a polylactic acid resin (A) and a polycarbonate resin (B) having a D-form content of 0 to 2.0 mol% or 98.0 to 100 mol%. The mass ratio of the polylactic acid resin (A) and the polycarbonate resin (B) is 20/80 to 80/20, and tin oxide (C) is added to the polylactic acid resin (A) and the polycarbonate resin (B). A polylactic acid resin composition comprising 0.005 to 10 parts by mass with respect to 100 parts by mass.
(2) Further, 0.1 to 20 parts by mass of the methyl methacrylate copolymer (D) is contained with respect to 100 parts by mass in total of the polylactic acid resin (A) and the polycarbonate resin (B) ( 1) The polylactic acid resin composition according to the above.
(3) Furthermore, the impact resistance improver (G) is contained, and the impact resistance improver (G) is 0.5 to 100 parts by mass with respect to 100 parts by mass in total of the polylactic acid resin (A) and the polycarbonate resin (B). The polylactic acid resin composition according to (1) or (2), which contains 10 parts by mass.
(4) The polylactic acid resin (A) has a D-form content of 0 to 0.6 mol%, or 99.4 to 100 mol%, according to any one of (1) to (3) Polylactic acid resin composition.
(5) A molded product comprising the polylactic acid resin composition according to any one of (1) to (4).

In the present invention, since the polylactic acid resin (A) having a D-form content in a specific range is used, the stereoregularity is improved, so that the crystal performance is improved, and the heat resistance and moldability are remarkably improved. It can be a composition. Furthermore, the resin composition of this invention can improve the crystal performance of a polylactic acid resin (A) more by containing tin oxide (C), and can also improve wet heat durability.
Thus, by improving the crystal performance and wet heat durability of the polylactic acid resin (A), the crystal performance and wet heat durability of the polylactic acid resin composition of the present invention are further improved. Further, the wet heat durability is further improved.
In addition, by containing a specific amount of the polycarbonate resin (B), the resin composition of the present invention has improved heat resistance and impact resistance.

Furthermore, the impact resistance of the polylactic acid-based resin composition can be improved by containing the impact resistance improver (G), and the impact resistance is remarkably improved by using it together with tin oxide (C). Can be improved.
Therefore, the polylactic acid resin composition of the present invention can be suitably used for various molded product applications such as electrical and electronic equipment parts and miscellaneous molded products. And since the polylactic acid-type resin composition of this invention uses the resin derived from a natural product, it can contribute to the saving of depletion resources, such as petroleum, and its industrial utility value is very high.

Hereinafter, the present invention will be described in detail. The polylactic acid resin composition of the present invention contains a polylactic acid resin (A), a polycarbonate resin (B), and tin oxide (C).
First, the polylactic acid resin (A) will be described. The polylactic acid resin (A) needs to have a D-form content of 0 to 2.0 mol% or a D-form content of 98.0 to 100 mol%. Especially, it is 0-1.5 mol or it is preferable that it is 98.5-100 mol%, Furthermore, it is 0-1.0 mol%, or 99.0-100 mol% It is preferably 0 to 0.6 mol%, or most preferably 99.4 to 100 mol%.
When the D-form content is within this range, the crystallinity is excellent. That is, not only the crystallization speed is high and the moldability is excellent, but also the crystallization is sufficiently easy to proceed, so that a molded body excellent in heat resistance can be obtained.

Moreover, it becomes what is further excellent in crystallinity by containing the tin oxide (C) mentioned later. And about wet heat durability, it is an effect which improves mainly by containing tin oxide (C) mentioned below, but by using polylactic acid resin (A) whose D body content is this range, The wet heat durability is further improved. When the polylactic acid resin has a D-form content outside this range, it is difficult to sufficiently improve both crystallinity and wet heat durability even when tin oxide (C) is contained.
Thus, since tin oxide (C) has a high effect of improving the performance of the polylactic acid resin (A), it may be mainly contained in the polylactic acid resin (A) in the resin composition. It is preferable.

  In the present invention, the D-form content of the polylactic acid resin (A) is a ratio (mol%) occupied by the D lactic acid unit in the total lactic acid units constituting the polylactic acid resin (A). Therefore, for example, in the case of a polylactic acid resin (A) having a D-form content of 1.0 mol%, the polylactic acid resin (A) has a proportion of 1.0 mol% of D lactic acid units, and L lactic acid The proportion of units is 99.0 mol%.

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

The polylactic acid resin (A) preferably has a weight average molecular weight of 30,000 to 500,000, more preferably 50,000 to 300,000, and even more preferably 70,000 to 200,000.
When the weight average molecular weight is 500,000 or more, not only the compatibility with the polycarbonate resin is lowered, but also the extrusion is difficult because the viscosity is too high. On the other hand, when the weight average molecular weight is less than 30,000, it is difficult to obtain a resin composition exhibiting physical properties that can withstand practical use.

  In consideration of the moldability of the resin composition of the present invention, the polylactic acid resin (A) has a melt flow rate (measured at 190 ° C. under a load of 2.16 kg) of 0.1 to 50 g / 10 min. Among them, 0.2 to 40 g / 10 min is preferable, and 1 to 30 g / 10 min is most preferable. When the melt flow rate exceeds 50 g / 10 min, the melt viscosity is too low and the operability is poor, and the obtained molded product tends to be inferior in mechanical properties. When the melt flow rate is less than 0.1 g / 10 minutes, the load during the molding process becomes too high and the operability may be lowered.

  As polylactic acid resin (A) used for this invention, polylactic acid resin of the range which D body content prescribes | regulates by this invention among various commercially available polylactic acid resins can be used. In addition, among lactides, which are cyclic dimers of lactic acid, L-lactide having a sufficiently low D-form content or D-lactide having a sufficiently low L-form content is used as a raw material, and a known melt polymerization method is used. Alternatively, those produced by further using a solid phase polymerization method can be used.

  Moreover, the polylactic acid resin (A) of the present invention may have a crosslinked structure introduced therein. As a method for introducing a crosslinked structure, it is preferable to employ a method of blending a (meth) acrylic acid ester compound and a peroxide.

  Next, the polycarbonate resin (B) will be described. The polycarbonate resin (B) contains a bisphenol residue unit and a carbonate residue unit.

  Examples of bisphenols include 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, and 2,2-bis (3,5-dimethyl- 4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) Decane, 1,4-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclododecane, 4,4'-dihydroxydiphenyl ether, 4,4'-dithiodiphenol, 4,4 ' -Dihydroxy-3,3'-dichlorodiphenyl ether, 4,4'-dihydroxy-2,5-dihydroxydi Phenyl ether, and the like. In addition, diphenols described in US Pat. Nos. 2,999,835, 3,028,365, 3,334,154 and 4,131,575 can be used. These may be used alone or in combination of two or more.

  Examples of the precursor for introducing the carbonate residue unit include phosgene and diphenyl carbonate.

  The polycarbonate resin used in the present invention preferably has an intrinsic viscosity in the range of 0.30 to 0.64. If it exceeds 0.64, the melt viscosity of the resin composition becomes high, and kneading extrusion and injection molding tend to be difficult. If it is below 0.30, the impact strength of the resulting molded product tends to be insufficient.

  The mass ratio of the polylactic acid resin (A) and the polycarbonate resin (B) is 20/80 to 80/20, preferably 30/70 to 70/30, and more preferably 40/60 to 60/40. It is more preferable.

  By blending a specific amount of polylactic acid resin (A) and polycarbonate resin (B), a structure (so-called sea-island structure) in which polycarbonate resin (B) is dispersed like islands in polylactic acid resin (A) (sea) Can be obtained. The sea-island structure contributes to the improvement of impact resistance, and the molded article obtained can have good heat resistance and durability.

  When the proportion of the polylactic acid resin (A) is less than this range, the proportion of the plant-derived resin is too small to make an environment-friendly resin composition. On the other hand, when the proportion of the polylactic acid resin (A) is larger than this range, the proportion of the polycarbonate resin (B) is decreased, so that the resin composition is poor in heat resistance and impact resistance.

  The polylactic acid resin composition of the present invention preferably contains a methyl methacrylate copolymer (D). The methyl methacrylate copolymer (D) has an effect of improving the compatibility of the polylactic acid resin (A) and the polycarbonate resin (B). By improving the compatibility, the impact resistance of the resin composition is improved. It will be better.

  The methyl methacrylate copolymer (D) is a copolymer of methyl methacrylate and (meth) acrylic acid ester. That is, the methyl methacrylate copolymer (D) is a monomer mixture composed of methyl methacrylate and an acrylate ester, or a monomer composed of methyl methacrylate and a methacrylate ester excluding methyl methacrylate. It is a copolymer obtained by copolymerizing a mixture.

  As an acrylic ester, what has a C1-C18 alkyl group is preferable. The alkyl group of the acrylate ester may be linear or branched, and may be a cyclic alkyl group. Specifically, examples of the acrylate ester having a linear alkyl group include methyl acrylate, ethyl acrylate, n-butyl acrylate, lauryl acrylate, stearyl acrylate, and the like. Examples of the acrylate ester having a branched alkyl group include 2-ethylhexyl acrylate. Examples of the acrylate ester having a cyclic alkyl group include cyclohexyl acrylate. If the alkyl group has more than 18 carbon atoms, the monomer polymerizability may decrease and copolymerization may be difficult.

  As a methacrylic acid ester except methyl methacrylate, what has a C2-C18 alkyl group is preferable. The alkyl group of the methacrylic acid ester may be linear or branched, and may be a cyclic alkyl group. Specifically, examples of the methacrylic acid ester having a linear alkyl group include ethyl methacrylate, n-butyl methacrylate, lauryl methacrylate, stearyl methacrylate, tridecyl methacrylate and the like. Examples of the methacrylic acid ester having a branched alkyl group include i-butyl methacrylate, t-butyl methacrylate, and 2-ethylhexyl methacrylate. Examples of the methacrylic acid ester having a cyclic alkyl group include cyclohexyl methacrylate. If the alkyl group has more than 18 carbon atoms, the monomer polymerizability may decrease and copolymerization may be difficult.

  The methyl methacrylate copolymer (D) may be copolymerized with other types of monomers as long as the characteristics are not significantly impaired. Other types of monomers include aromatic alkenyl compounds such as styrene, α-methylstyrene, chlorostyrene and vinyltoluene; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; vinyl esters such as vinyl acetate; maleic anhydride And dicarboxylic acid anhydrides such as divinylbenzene and allyl methacrylate. In the present invention, these may be used alone or in combination of two or more according to the purpose.

  In the resin composition of the present invention, the content of the methyl methacrylate copolymer (D) is 0.1 to 20 mass with respect to a total of 100 mass parts of the polylactic acid resin (A) and the polycarbonate resin (B). Parts, preferably 1 to 10 parts by mass. When the content of the methyl methacrylate copolymer (D) is less than 0.1 parts by mass, the effect of improving the compatibility between the polylactic acid resin (A) and the polycarbonate resin (B) is poor, and the fusion impact resistance The improvement effect becomes insufficient. On the other hand, when the content of the methyl methacrylate copolymer (D) exceeds 20 parts by mass, the heat resistance is lowered.

  In the polylactic acid-based resin composition of the present invention, as long as the effect is not impaired, the resin component other than the polylactic acid resin (A), the polycarbonate resin (B), and the methyl methacrylate-based copolymer (D) Other resins may be contained. Examples thereof include polyamide, polyolefin polyester, polystyrene, AS (acrylonitrile-styrene) resin, ABS (acrylonitrile-butadiene-styrene) resin, poly (acrylic acid), poly (acrylic acid ester), polyethylene naphthalate, and the like.

  In addition, the total content of the polylactic acid resin (A) and the polycarbonate resin (B) in the polylactic acid resin composition of the present invention is preferably 60% by mass or more, more preferably 70% by mass or more, It is preferable that it is 80 mass% or more.

And the polylactic acid-type resin composition of this invention contains a tin oxide (C) further. Examples of tin oxide (C) used in the present invention include SnO (stannous oxide), SnO ₂ (stannic oxide), SnO _{3 and the} like. Among them, it is preferable to use SnO ₂ because it is relatively easy to obtain. Tin oxide (C) may be in a crystalline state or an amorphous state. Tin oxide (C) improves the crystallinity and wet heat durability of polylactic acid resin (A) by containing a specific amount in the polylactic acid resin (A) having a D-form content in a specific range as described above. be able to.

  The content of tin oxide (C) needs to be 0.005 to 10 parts by mass with respect to a total of 100 parts by mass of the polylactic acid resin (A) and the polycarbonate resin (B). It is preferably ˜5 parts by mass, more preferably 0.02 to 3 parts by mass. When the content of tin oxide (C) is less than 0.005 parts by mass, it is difficult to improve the crystallinity and wet heat durability of the polylactic acid resin (A). On the other hand, when the amount exceeds 10 parts by mass, the specific gravity of the resin composition increases, the use is restricted, and the surface of the resulting molded article is inferior in quality such as a glare sensation.

  The average particle diameter of tin oxide (C) is preferably 1 μm to 10 μm, more preferably 2 μm to 5 μm. If the average particle size is less than 1 μm, the polylactic acid resin is easily decomposed because it easily absorbs moisture, and the dispersibility deteriorates because it tends to aggregate, which is not preferable. On the other hand, when the average particle diameter exceeds 10 μm, the surface area becomes small, so that the effect of improving the crystallinity and wet heat durability as described above is poor, which is not preferable.

  For the tin oxide (C), it is preferable to use particles formed only of tin oxide, but metal oxides other than tin oxide, or particles having a metal or polymer surface coated with tin oxide are also used. be able to. Alternatively, particles made of tin oxide (C) doped with an element such as indium or antimony may be used. Even when such tin oxide (C) is used, the content of only tin oxide satisfies the above range.

  As a method for measuring the content of tin oxide (C) in the polylactic acid resin composition of the present invention, a method for measuring the amount of tin in the resin composition by inductively coupled plasma (ICP) measurement, a resin composition Examples thereof include a method of dissolving a substance in a solvent or the like to remove the resin, and a method of performing X-ray analysis on the remaining inorganic component and a method of measuring with an Auger microprobe.

The polylactic acid resin composition of the present invention preferably further contains an impact resistance improver (G). In the present invention, by using the impact resistance improver (G) together with tin oxide (C), the impact resistance is remarkably improved.
The impact resistance improver (G) is preferably at least one of the core-shell type graft copolymer (G1) and the (meth) acrylic acid ester polymer (G2).

First, the core-shell type graft copolymer (G1) will be described.
The core-shell type graft copolymer (G1) is composed of a core layer and a shell layer covering the core layer, and adjacent layers are composed of different polymers. Each of the core layer and the shell layer may have a plurality of layers. The core-shell type graft copolymer (G1) is preferably obtained by graft polymerization of the shell layer component in the presence of the core layer component.

  In the present invention, the core-shell type graft copolymer (G1) is preferably selected from butadiene rubber, acrylic rubber, and silicone rubber from the viewpoint of improving impact resistance.

The butadiene rubber forming the core layer component is a polymer composed of only 1,3-butadiene monomer, or 1,3-butadiene monomer and at least one vinyl copolymer copolymerizable therewith. A polymer comprising a monomer.
The content of the one or more vinyl monomers in the butadiene rubber is preferably 50% by mass or less, and more preferably 30% by mass or less.

  Examples of vinyl monomers copolymerizable with 1,3-butadiene monomer include aromatic vinyl compounds such as styrene and α-methylstyrene, alkyl methacrylates such as methyl methacrylate and ethyl methacrylate, ethyl acrylate, n -Alkyl acrylates such as butyl acrylate, unsaturated nitriles such as acrylonitrile and methacrylonitrile, vinyl ethers such as methyl vinyl ether and butyl vinyl ether, vinyl halides such as vinyl chloride and vinyl bromide, vinylidene chloride and vinylidene bromide Examples thereof include vinyl monomers having a glycidyl group such as vinylidene halide, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and ethylene glycol glycidyl ether.

  In addition to the above, aromatic polyfunctional vinyl compounds such as divinylbenzene and divinyltoluene, polyhydric alcohols such as ethylene glycol dimethacrylate and 1,3-butanediol diacrylate, trimethacrylates, triacrylates, acrylics Crosslinkable monomers (crosslinking agents) such as carboxylic acid allyl esters such as allyl acid and allyl methacrylate, diallyl compounds such as diallyl phthalate and diallyl sebacate, and triallyl compounds such as triallyl triazine can be used. These can be used alone or in admixture of two or more.

The acrylic rubber forming the core layer component preferably contains 50 to 100% by mass of the main structural unit acrylate, and more preferably 70 to 100% by mass. In the acrylic rubber, the other component than the acrylic ester is preferably a vinyl monomer copolymerizable with the acrylic ester.
Examples of the acrylic acid ester constituting the acrylic rubber include an acrylic acid alkyl ester having an alkyl group having 2 to 8 carbon atoms, and examples thereof include ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and the like.

  Examples of vinyl monomers copolymerizable with acrylic esters include aromatic vinyl compounds such as styrene and α-methylstyrene, alkyl methacrylates such as methyl methacrylate and ethyl methacrylate, and unsaturated groups such as acrylonitrile and methacrylonitrile. Vinyl ethers such as nitrile, methyl vinyl ether and butyl vinyl ether, vinyl halides such as vinyl chloride and vinyl bromide, vinylidene halides such as vinylidene chloride and vinylidene bromide, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, ethylene glycol glycidyl ether, etc. And vinyl monomers having a glycidyl group.

The silicone rubber forming the core layer component is a rubber containing polyorganosiloxane which is a linear polymer having an organosiloxane bond unit of several thousand or more, and includes polyorganosiloxane and alkyl (meth) acrylate rubber. Including silicone-acrylic rubber.
The rubber may be produced by any method, but the emulsion polymerization method is optimal.

  The structure of the polyorganosiloxane is not particularly limited but is preferably a polyorganosiloxane containing a vinyl polymerizable functional group. Examples of the dimethylsiloxane used in the production of the polyorganosiloxane include a dimethylsiloxane-based cyclic body having a 3-membered ring or more, and a 3- to 7-membered ring is preferable. Specific examples include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and the like. These may be used alone or in combination of two or more.

  In the present invention, the shell layer component constituting the core-shell type graft copolymer (G1) is an unsaturated carboxylic acid alkyl ester unit, a glycidyl group-containing vinyl unit, an aliphatic vinyl unit, an aromatic vinyl unit, cyanide. It is preferably formed of a polymer containing a vinyl-based unit, a maleimide-based unit, an unsaturated dicarboxylic acid-based unit, an unsaturated dicarboxylic anhydride-based unit, and / or other vinyl-based units. Among them, a polymer containing an unsaturated carboxylic acid alkyl ester unit, a glycidyl group-containing vinyl unit and / or an unsaturated dicarboxylic acid anhydride unit is preferable, and a polymer containing an unsaturated carboxylic acid alkyl ester unit is preferable. Is more preferable.

  As the unsaturated carboxylic acid alkyl ester unit constituting the polymer of the shell layer component, (meth) acrylic acid alkyl ester is preferably used. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, (meth) acrylic N-hexyl acid, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, stearyl (meth) acrylate, octadecyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, ( Chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2,3,4,5,6 (meth) acrylic acid -Pentahydroxyhexyl, 2,3,4,5-tetrahydroxypentyl (meth) acrylate, amino acid acrylate Examples include ethyl, propylaminoethyl acrylate, dimethylaminoethyl methacrylate, ethylaminopropyl methacrylate, phenylaminoethyl methacrylate, cyclohexylaminoethyl methacrylate, etc., from the viewpoint that the effect of improving dispersibility in the resin is great. , Methyl (meth) acrylate and n-butyl (meth) acrylate are preferably used. These units can be used alone or in combination of two or more.

  The glycidyl group-containing vinyl-based unit constituting the polymer of the shell layer component is not particularly limited, and is glycidyl (meth) acrylate, glycidyl itaconate, diglycidyl itaconate, allyl glycidyl ether, styrene-4-glycidyl. Ether, 4-glycidyl styrene and the like are mentioned, and glycidyl (meth) acrylate is preferably used from the viewpoint that the effect of improving impact resistance is great. These units can be used alone or in combination of two or more.

  Examples of the aliphatic vinyl units constituting the polymer of the shell layer component include ethylene, propylene, and butadiene. Examples of aromatic vinyl units include styrene, α-methylstyrene, 1-vinylnaphthalene, 4-methylstyrene, 4-propylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4 -(Phenylbutyl) styrene, halogenated styrene, etc. are mentioned. Examples of the vinyl cyanide unit include acrylonitrile, methacrylonitrile, ethacrylonitrile and the like. The maleimide units include maleimide, N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N- (p-bromophenyl) maleimide, N- And (chlorophenyl) maleimide. Examples of unsaturated dicarboxylic acid units include maleic acid, maleic acid monoethyl ester, itaconic acid, and phthalic acid.

  Other vinyl units constituting the polymer of the shell layer component include acrylamide, methacrylamide, N-methylacrylamide, butoxymethylacrylamide, N-propylmethacrylamide, N-vinyldiethylamine, N-acetylvinylamine, allylamine, Examples include methallylamine, N-methylallylamine, p-aminostyrene, 2-isopropenyl-oxazoline, 2-vinyl-oxazoline, 2-acryloyl-oxazoline, and 2-styryl-oxazoline. These units can be used alone or in combination of two or more.

  Among the core-shell type graft copolymers (G1) obtained by combining the core layer and the shell layer as described above, the following three core-shell type graft copolymers (G1-1) to (G1-3) are impact resistant. The effect of improving the property is excellent, and (G1-1) described below is particularly preferable.

The core-shell type graft copolymer (G1-1) is a composite polymer in which the core layer is composed of an acrylic component and a silicone component, and the shell layer is a heavy polymer having an unsaturated carboxylic acid alkyl ester unit or a vinyl unit. Among them, a polymer containing methyl (meth) acrylate or a glycidyl group-containing vinyl-based unit is preferable.
Examples of commercially available core-shell type graft copolymers (G1-1) include Metablene S-2001, Metabrene S-2006, and Metabrene S-2200 manufactured by Mitsubishi Rayon Co., Ltd.

The core-shell type graft copolymer (G1-2) is a polymer in which the core layer is a butadiene-based rubber and the shell layer has an unsaturated carboxylic acid alkyl ester-based unit. Among them, the core layer is preferably a methyl methacrylate / butadiene copolymer rubber, and the shell layer is preferably a polymer having a methyl (meth) acrylate unit.
Commercially available products of the core-shell type graft copolymer (G1-2) include Metablene C-223A manufactured by Mitsubishi Rayon Co., Ltd., Kaneace B-564 manufactured by Kaneka Co., Ltd. and Paraloid BPM-520 manufactured by Rohm and Haas Co.

The core-shell type graft copolymer (G1-3) is made of a polymer in which the core layer contains an acrylic rubber and the shell layer contains an unsaturated carboxylic acid alkyl ester unit. In particular, the shell layer grafts one or more unsaturated carboxylic acid alkyl ester units, particularly methyl (meth) acrylate, onto the core layer acrylic rubber in the presence of the core layer acrylic rubber. It is preferable that it is obtained by polymerizing.
Examples of commercially available core-shell type graft copolymers (G1-3) include Rohm and Haas Paraloid BPM-500, Paraloid BPM-515, Mitsubishi Rayon Metabrene W-450A, and Metabrene W-600A.

  Next, the (meth) acrylic acid ester polymer (G2) will be described. As a monomer which comprises a (meth) acrylic acid ester polymer, acrylic acid and its ester, methacrylic acid and its ester are mentioned, for example. These monomers may be used independently and may be used in combination of 2 or more type. Examples of the copolymer include a block copolymer, a random copolymer, a graft copolymer, or a combination thereof.

Specific examples of (meth) acrylic acid and its esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl (meth) acrylate. , Isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, neopentyl (meth) acrylate, ethylhexyl (meth) acrylate, isodecyl acrylate, lauryl (meth) acrylate , Tridecyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, methoxyethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, (meth ) Chloroethyl acrylate, Trifluoro (meth) acrylate Ethyl, (meth) heptadecafluorooctyl acrylate, isobornyl (meth) acrylate, and (meth) adamantyl acrylate and (meth) tricycloalkyl Desi sulfonyl acrylate. Further, monomers such as substituted styrene such as styrene, α-methylstyrene, t-butylstyrene and chlorostyrene may be copolymerized.
What is necessary is just to produce a (meth) acrylic acid ester-type copolymer using a well-known method.

As a 1st preferable aspect of a (meth) acrylic acid ester polymer (G2), the ultrahigh molecular weight (meth) acrylic acid ester polymer whose weight average molecular weight is 500,000 or more and less than 10 million is mentioned. By using an ultra high molecular weight (meth) acrylic acid ester polymer having a weight average molecular weight in the above range, impact resistance is remarkably improved and flexibility is improved. If the weight average molecular weight is less than 500,000, the effect of improving impact resistance and flexibility cannot be obtained sufficiently. On the other hand, when the weight average molecular weight exceeds 10,000,000, the compatibility of the resulting resin composition is impaired, or the melt viscosity becomes too high and it becomes difficult to handle.
The weight average molecular weight of such a (meth) acrylic acid ester polymer is more preferably 800,000 to 8 million, and still more preferably 1 million to 5 million.

  Examples of commercially available products of the (meth) acrylic acid ester polymer (G2) of the first preferred embodiment include, for example, the Metabrene P series manufactured by Mitsubishi Rayon Co., the PARALOID K series manufactured by Rohm and Haas, and the Kaneka Corporation. Kane Ace PA series.

A second preferred embodiment of the (meth) acrylate polymer (G2) includes a block copolymer of methyl methacrylate and n-butyl acrylate (hereinafter referred to as block copolymer P). . By using this block copolymer P, impact resistance is remarkably improved, and flexibility and impact resistance against falling ball impact and falling weight impact are also improved.
Since the effect of improving the flexibility and impact resistance is sufficiently obtained, the proportion of the n-butyl acrylate monomer in the monomer constituting the block copolymer P is preferably 60% by mass or more, 75 mass% or more is more preferable.
The block copolymer P has a molecular chain composed of a hard block composed of 1 to 5 methyl methacrylate units and a soft block composed of 1 to 5 n-butyl acrylate units. Is preferred.

  The hard block composed of methyl methacrylate units in the molecular chain of the block copolymer P contributes to good compatibility with the polylactic acid resin (A) and the polycarbonate resin (B). The soft block composed of n-butyl acrylate units in the molecular chain of the block copolymer P contributes to improvement in flexibility and impact resistance.

  As a commercial item of the block copolymer P of the 2nd preferable aspect of the (meth) acrylic acid ester type polymer (G2), for example, a trade name “Clarity LA2140e” (containing n-butyl acrylate) manufactured by Kuraray The amount is 77% by mass), and the trade name “Clarity LA2250” manufactured by Kuraray Co., Ltd. (the content of n-butyl acrylate is 67% by mass).

In consideration of the effect of imparting impact resistance to the resin composition, the content of the impact resistance improver (G) in the polylactic acid resin composition of the present invention is such that the polylactic acid resin (A) and the polycarbonate resin (B). 0.5 to 10 parts by mass is preferable, 1 to 9 parts by mass is more preferable, and 3 to 8 parts by mass is particularly preferable.
When the content of the impact resistance improver (G) is less than 0.5 parts by mass, sufficient impact resistance cannot be imparted to the resin composition. On the other hand, when the content of the impact resistance improver (G) exceeds 10 parts by mass, the impact resistance improving effect is saturated and the crystallinity of the resin composition is lowered.

  And it is preferable that the carbodiimide compound contains in the polylactic acid-type resin composition of this invention. Although it is known that when a carbodiimide compound is added to a polylactic acid resin, the wet heat durability of the polylactic acid resin is improved, in the present invention, the polylactic acid resin (A) having a D-form content in a specific range, tin oxide By using together with (C), the wet heat durability is remarkably improved.

  Various compounds can be used as the carbodiimide compound. As specific compounds, N, N′-di-2,6-diisopropylphenylcarbodiimide, N, N′-di-o-tolylcarbodiimide, N, N′-diphenylcarbodiimide, N, N′-dioctyldecylcarbodiimide, N, N'-di-2,6-dimethylphenylcarbodiimide, N-tolyl-N'-cyclohexylcarbodiimide, N, N'-di-2,6-di-tert-butylphenylcarbodiimide, N-tolyl-N ' -Phenylcarbodiimide, N, N'-di-p-nitrophenylcarbodiimide, N, N'-di-p-aminophenylcarbodiimide, N, N'-di-p-hydroxyphenylcarbodiimide, N, N'-di- Cyclohexylcarbodiimide, N, N'-di-p-tolylcarbodiimide, p-phenylene-bis-di-o-to Carbodiimide, p-phenylene-bis-dicyclohexylcarbodiimide, hexamethylene-bis-dicyclohexylcarbodiimide, ethylene-bis-diphenylcarbodiimide, N, N'-benzylcarbodiimide, N-octadecyl-N'-phenylcarbodiimide, N-benzyl-N '-Phenylcarbodiimide, N-octadecyl-N'-tolylcarbodiimide, N-cyclohexyl-N'-tolylcarbodiimide, N-phenyl-N'-tolylcarbodiimide, N-benzyl-N'-tolylcarbodiimide, N, N'- Di-o-ethylphenylcarbodiimide, N, N'-di-p-ethylphenylcarbodiimide, N, N'-di-o-isopropylphenylcarbodiimide, N, N'-di-p-isopropylphenylcarbodiimide Diimide, N, N'-di-o-isobutylphenylcarbodiimide, N, N'-di-p-isobutylphenylcarbodiimide, N, N'-di-2,6-diethylphenylcarbodiimide, N, N'-di- 2-ethyl-6-isopropylphenylcarbodiimide, N, N'-di-2-isobutyl-6-isopropylphenylcarbodiimide, N, N'-di-2,4,6-trimethylphenylcarbodiimide, N, N'-di -2,4,6-triisopropylphenylcarbodiimide, N, N'-di-2,4,6-triisobutylphenylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, di- β-naphthylcarbodi De, and the like di -t- butyl carbodiimide

  And as what is marketed among these compounds, for example, monocarbodiimide having one carbodiimide group in the same molecule such as EN-160 manufactured by Matsumoto Yushi Seiyaku Co., Ltd. Examples thereof include polycarbodiimide having two or more carbodiimide groups in the same molecule, such as EN-180 manufactured by Matsumoto Yushi Seiyaku Co., Ltd., Stavacsol P manufactured by Rhein Chemie, and Carbodilite LA-1 manufactured by Nisshinbo Industries, Ltd.

  Among these, monocarbodiimide is highly effective in improving the wet heat durability of the polylactic acid resin when used in combination with stannic oxide, and it is particularly preferable to use N, N′-di-2,6-diisopropylphenylcarbodiimide. Examples of such commercially available monocarbodiimide include EN160 manufactured by Matsumoto Yushi Seiyaku Co., Ltd. and Stavacsol I manufactured by Rhein Chemie.

  The content of the carbodiimide compound is preferably 0.1 to 10 parts by mass with respect to a total of 100 parts by mass of the polylactic acid resin (A) and the polycarbonate resin (B). Especially, it is preferable that it is 0.3-8.0 mass parts, and it is more preferable that it is 0.5-5.0 mass%. When the content of the carbodiimide compound is less than 0.1 parts by mass, it is difficult to obtain the effect of improving the wet heat durability as described above. On the other hand, when the content of the carbodiimide compound exceeds 10 parts by mass, not only the effect is saturated but also other physical properties such as strength reduction are adversely affected.

  Since the polylactic acid resin composition of the present invention uses a polylactic acid resin (A) having a D-form content in a specific range, the crystallinity is sufficiently improved without adding a crystal nucleating agent. Is. However, a crystal nucleating agent may be contained for the purpose of further improving crystallinity (mainly crystallization speed).

  Specific compounds that can be used as the crystal nucleating agent are selected from organic amide compounds, organic hydrazide compounds, carboxylic acid ester compounds, organic sulfonates, phthalocyanine compounds, melamine compounds, and organic phosphonates. It is preferable to use one or more. Among these, organic sulfonates, organic amide compounds, and organic phosphonates are preferable from the viewpoint of crystallization speed.

  As the organic sulfonate, various compounds such as sulfoisophthalate can be used, and among them, dimethyl metal salt of 5-sulfoisophthalic acid is preferable from the viewpoint of the effect of promoting crystallization. Furthermore, barium salt, calcium salt, strontium salt, potassium salt, rubidium salt, sodium salt and the like are preferable. Examples of commercially available products include LAK403 manufactured by Takemoto Yushi Co., Ltd.

  Various kinds of organic amide compounds can be used. Among these, N, N ′, N ″ -tricyclohexyltrimesic acid amide, N, N ′ are preferred from the viewpoint of dispersibility in the resin and heat resistance. -Ethylene bis (12-hydroxystearic acid) amide is preferable, and examples of commercially available products include AS-AT-530SF manufactured by Ito Oil Co., Ltd.

As the organic phosphonate, phenyl phosphonate is preferred from the viewpoint of the effect of promoting crystallization. The metal salt of phenylphosphonic acid is a metal salt of phenylphosphonic acid having a phenyl group which may have a substituent and a phosphone group (—PO (OH) ₂ ), and the substituent of the phenyl group includes carbon. Examples thereof include an alkyl group having 1 to 10 carbon atoms and an alkoxycarbonyl group having 1 to 10 carbon atoms in the alkoxy group. Specific examples of phenylphosphonic acid include unsubstituted phenylphosphonic acid, methylphenylphosphonic acid, ethylphenylphosphonic acid, propylphenylphosphonic acid, butylphenylphosphonic acid, dimethoxycarbonylphenylphosphonic acid, and diethoxycarbonylphenylphosphonic acid. And unsubstituted phenylphosphonic acid is preferred. Of these, zinc phenylphosphonate is particularly preferable.

  Examples of the metal salt of phenylphosphonic acid include salts of lithium, sodium, magnesium, aluminum, potassium, calcium, barium, copper, zinc, iron, cobalt, nickel, etc. Among these metal salts, a zinc salt is selected. It is preferable. Examples of commercially available products include Eco Promote (zinc phenylphosphonate) manufactured by Nissan Chemical Co., Ltd.

  In the polylactic acid resin composition of the present invention, the content of the crystal nucleating agent as described above is 0.03 to 5 parts by mass with respect to 100 parts by mass in total of the polylactic acid resin (A) and the polycarbonate resin (B). In particular, 0.1 to 4 parts by mass is more preferable, and 0.5 to 3 parts by mass is most preferable. When the content of the crystal nucleating agent is less than 0.03 parts by mass, the effect of improving the crystallinity of the polylactic acid resin (A) is poor. On the other hand, when the content exceeds 5 parts by mass, the effect as a crystal nucleating agent is saturated, which is not only economically disadvantageous, but also increases the residue after biodegradation, which is not preferable in terms of environment.

  In the polylactic acid resin composition of the present invention, a plasticizer, a heat stabilizer, an antioxidant, a filler, a pigment, a weathering agent, a flame retardant, a lubricant, a mold release agent, as long as the effects of the present invention are not impaired. Additives such as antistatic agents can be added.

  As the plasticizer, polyester plasticizers, glycerin plasticizers, polycarboxylic acid ester plasticizers, phosphate ester plasticizers, polyalkylene glycol plasticizers, epoxy plasticizers, and the like can be used.

Examples of heat stabilizers and antioxidants include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and vitamin E.
Examples of the filler include inorganic fillers and organic fillers. Inorganic fillers include talc, zinc carbonate, wollastonite, silica, aluminum oxide, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, carbon black, zinc oxide , Antimony trioxide, zeolite, metal fiber, metal whisker, ceramic whisker, potassium titanate, boron nitride, graphite, glass fiber, carbon fiber and the like. Examples of the organic filler include naturally occurring polymers such as starch, cellulose fine particles, wood flour, okara, fir shell, bran, kenaf, and modified products thereof.

As the flame retardant, a halogen-based flame retardant, a phosphorus-based flame retardant, and an inorganic flame retardant can be used. However, in consideration of the environment, it is desirable to use a non-halogen flame retardant. Non-halogen flame retardants include phosphorus flame retardants, hydrated metal compounds (aluminum hydroxide and magnesium hydroxide), N-containing compounds (melamine and guanidine), and inorganic compounds (borate and Mo compounds). It is done.
As the lubricant, various carboxylic acid compounds can be used, and among them, various fatty acid metal salts, particularly magnesium stearate, calcium stearate and the like are preferable.
As the release agent, various carboxylic acid compounds, among them, various fatty acid esters, various fatty acid amides, and the like are preferably used.

  Next, the manufacturing method of the polylactic acid-type resin composition of this invention is demonstrated. The polylactic acid-type resin composition of this invention can be obtained by supplying each component which comprises a resin composition in an extruder, and melt-kneading. However, tin oxide (C) and additives used as necessary (impact resistance improver (G), carbodiimide compound and crystal nucleating agent) are preferably contained in the polylactic acid resin (A). It is preferable to employ a method of adding at the polymerization of the polylactic acid resin (A), a method of adding tin oxide (C) or an additive used as necessary to the polylactic acid resin (A) and melt-kneading.

  In addition, in the case of the method of adding at the time of polymerization of the polylactic acid resin (A), a vertical reactor or a horizontal reactor equipped with a helical ribbon blade, a high-viscosity stirring blade or the like is used as a reaction vessel for performing melt ring-opening polymerization. Can be used alone or in parallel. In addition, the reaction vessel may be a continuous type, a batch type or a semi-batch type, or a combination thereof.

  In the case of the method of adding to the polylactic acid resin (A) by melt-kneading, after dry-blending with the polylactic acid resin (A) in advance, a method of supplying to a general kneader or molding machine, The method of adding from the middle of melt-kneading using a feeder is mentioned.

  In melt kneading, a general kneader such as a single screw extruder, a twin screw extruder, a roll kneader, or a Brabender can be used. From the viewpoint of improving mixing uniformity and dispersibility, it is preferable to use a twin screw extruder.

  Next, the molded article of the present invention is molded using the polylactic acid resin composition of the present invention as described above. Especially, it is preferable that it is a molded object shape | molded using only the polylactic acid-type resin composition of this invention.

  Examples of the molded body of the present invention include those obtained by using the polylactic acid resin composition of the present invention and various molded bodies by known molding methods such as injection molding, blow molding, and extrusion molding. Since the polylactic acid-based resin composition of the present invention has a high crystallization rate, it is possible to shorten the molding cycle when obtaining a molded body, and is excellent in molding processability.

As an injection molding method, in addition to a general injection molding method, gas injection molding, injection press molding, or the like can be adopted. In the present invention, as an example of suitable injection molding conditions, the cylinder temperature is equal to or higher than the melting point (Tm) or flow start temperature of the polylactic acid resin, preferably in the range of 180 to 230 ° C, and optimally in the range of 190 to 220 ° C. It is. If the cylinder temperature is too low, it tends to cause molding failure or overload of the device due to a decrease in fluidity of the resin. On the other hand, if the cylinder temperature is too high, the polylactic acid resin is decomposed, and problems such as a decrease in strength of the molded product and coloring may occur.
In the present invention, the mold temperature at the time of injection molding is preferably (Tg-10) ° C. or lower when the temperature is set to Tg (glass transition temperature) or lower of the resin composition. Moreover, in order to accelerate | stimulate crystallization for the purpose of the rigidity of a resin composition, and heat resistance improvement, it can also be Tg or more and (Tm-30) degreeC or less.

  Examples of the blow molding method include a direct blow method in which molding is performed directly from raw material chips, an injection blow molding method in which blow molding is performed after a preformed body (bottom parison) is first molded by injection molding, and a stretch blow molding method. Etc. In addition, any of a hot parison method in which blow molding is continuously performed after forming the preform, and a cold parison method in which the preform is cooled and taken out and then heated again to perform blow molding can be employed.

  As the extrusion molding method, a T-die method, a round die method, or the like can be applied. The extrusion molding temperature must be equal to or higher than the melting point or flow start temperature of the raw polylactic acid resin, and is preferably in the range of 180 to 230 ° C, more preferably 190 to 220 ° C. If the molding temperature is too low, there are problems that the operation becomes unstable and that overload tends to occur. On the other hand, if the molding temperature is too high, the polylactic acid resin is decomposed, and problems such as a decrease in strength and coloration of the extruded molded product occur.

  And a sheet | seat, a pipe, etc. can be produced by extrusion molding. Specific applications of the sheet or pipe obtained by the extrusion method include: deep drawing raw sheet, batch-type foam original sheet, credit cards and other cards, underlays, clear files, straws, agriculture / horticulture Hard pipes for use. In addition, the sheet can be further subjected to deep drawing such as vacuum forming, pressure forming and vacuum / pressure forming to produce food containers, agricultural / horticultural containers, blister pack containers and press-through pack containers. it can.

  The molded article of the present invention obtained by the molding method as described above has excellent heat resistance, moldability, wet heat durability and the like possessed by the polylactic acid resin composition of the present invention. It can be used suitably. Specific examples of automotive parts include bumper members, instrument panels, trims, torque control levers, safety belt parts, register blades, washer levers, window regulator handles, window regulator handle knobs, passing light levers, sun visor brackets, Console box, trunk cover, spare tire cover, ceiling material, floor material, inner plate, seat material, door panel, door board, steering wheel, rearview mirror housing, air duct panel, wind molding fastener, speed cable liner, sun visor bracket, Headrest rod holders, various motor housings, various plates, various panels, etc.

  In addition, it can be suitably used for applications such as office equipment that requires these performances, housings for home appliances, and various parts. Specific examples of office equipment include a front cover, a rear cover, a paper feed tray, a paper discharge tray, a platen, an interior cover, and a toner cartridge in a casing of a printer, a copying machine, a fax machine, and the like. In addition, it can be suitably used for various applications that require wet heat durability, such as electrical / electronic parts, medical care, food, household / office supplies, office automation equipment, building material-related parts, and furniture parts.

  As the molded article of the present invention, other than the above, dishes such as dishes, bowls, bowls, chopsticks, spoons, forks, knives; fluid containers; container caps; rulers, writing instruments, clear cases, CD cases, etc. Office supplies; daily necessaries such as kitchen corners, trash cans, washbasins, toothbrushes, combs, hangers, etc .; agricultural and horticultural materials such as flower pots and nursery pots; various toys such as plastic models.

Hereinafter, the present invention will be described more specifically with reference to examples. The measurement and evaluation of various characteristic values in the examples were performed as follows.
(1) D-form content of polylactic acid resin 0.3 g of the obtained resin composition was weighed, added to 6 mL of 1N potassium hydroxide / methanol solution, and sufficiently stirred at 65 ° C. Subsequently, 450 μL of sulfuric acid was added and stirred at 65 ° C. to decompose polylactic acid, and 5 mL was measured as a sample.
To this sample, 3 mL of pure water and 13 mL of methylene chloride were mixed and shaken. After stationary separation, about 1.5 mL of the lower organic layer was collected, filtered through a HPLC disk filter having a pore size of 0.45 μm, and then subjected to gas chromatography measurement using HP-6890 Series GC system manufactured by Hewlett Packard. The ratio (%) of the peak area of D-lactic acid methyl ester to the total peak area of lactic acid methyl ester was calculated, and this was defined as the D-form content (mol%) of the polylactic acid resin (A).
(2) Melt flow rate (MFR) of polylactic acid resin
According to JIS K-7210, it measured with the load of 190 degreeC and 21.2N.
(3) Weight average molecular weight of polylactic acid resin Using a gel permeation chromatography (GPC) apparatus (manufactured by Shimadzu Corporation) equipped with a differential refractive index detector, tetrahydrofuran or chloroform is used as an eluent and obtained in terms of standard polystyrene. It was.

(4) Content of tin oxide The obtained polylactic acid resin composition was determined by quantifying the tin content by a calibration curve method quantitative analysis method using an ICP analyzer. Sample preparation was performed by microwave wet digestion.
(5) Thermal deformation temperature (heat resistance)
Using the obtained test piece, the heat distortion temperature (DTUL) was measured at a load of 0.45 MPa in accordance with ISO 75-1 or 2.
(6) Molding cycle (crystallization speed)
The time from when the resin composition is injected into the mold (filling, holding pressure) and cooling, when the test piece is obtained, until the molded body can be taken out without being fixed to the mold. (Time counted from the time of injection: second) or time until the molded body can be removed from the mold without resistance (time counted from the time of injection: second) was defined as a molding cycle. The upper limit molding cycle at that time was 180 seconds.

(7) Bending strength retention (wet heat durability)
Wet heat durability 1: Using the obtained test piece, the load at a deformation rate of 2 mm / min was applied according to ISO 178, and the bending break strength was measured (the bending break strength before the wet heat treatment). After the test piece of the resin composition to which no carbodiimide compound was added was exposed to a high temperature and high humidity environment of 60 ° C. and 95% RH for 300 hours, the bending fracture strength of the test piece was measured in the same manner as described above (wet Bending fracture strength after heat treatment). And based on the following formula | equation, the bending fracture strength retention was computed.
Bending strength retention (%) = [(Bending strength after wet heat treatment) / (Bending strength before wet heat treatment)] × 100
Wet heat durability 2: For a test piece of a resin composition to which a carbodiimide compound was added, after being exposed to a high temperature and high humidity environment of 60 ° C. and 95% RH for 3000 hours, the bending fracture strength of the test piece was set in the same manner as described above. Measured (the bending rupture strength after wet heat treatment). And based on the following formula | equation, the bending fracture strength retention was computed.
Bending strength retention (%) = [(Bending strength after wet heat treatment) / (Bending strength before wet heat treatment)] × 100
(8) Impact resistance The obtained polylactic acid resin composition was set to a cylinder temperature of 160 to 200 ° C. and a mold temperature of 100 ° C. using an injection molding machine (manufactured by Nissei Plastic Co., Ltd., NEX-110 type). , A test piece with a V-shaped notch (size; length × width × thickness: 80 mm × 10 mm × 4 mm) was obtained. And according to ISO 179-1, Charpy impact strength was measured using the obtained test piece.

Various raw materials used in Examples and Comparative Examples are as follows.
[Polylactic acid resin]
A-1: D-form content = 0.1 mol%, weight average molecular weight 130,000, MFR = 8 (manufactured by Toyota Motor Corporation; S-12)
A-2: D-form content = 1.4 mol%, weight average molecular weight 130,000, MFR = 10 (manufactured by Unitika Ltd .; TE-4000)
X-1: D-form content = 4.0 mol%, weight average molecular weight 160,000, MFR = 4 (manufactured by Nature Works; 4042D)
[Polycarbonate resin]
B-1: Weight average molecular weight 64,000 (manufactured by Sumitomo Dow, Caliber 200-13)

[Tin compounds]
C-1: stannic oxide (IV) (manufactured by Showa Kako)
Y-1: Tin powder (Kishida Chemical Co., Ltd.)
Y-2: stannous chloride (Ishizu Pharmaceutical)
[Methyl methacrylate copolymer]
D-1: Modiper A4200 (manufactured by NOF Corporation)

[Crystal nucleating agent]
E-1: 5-sulfoisophthalic acid dimethyl barium salt (LAK403, Takemoto Yushi Co., Ltd.)
[Carbodiimide compound]
F-1: N, N′-di-2,6-diisopropylphenylcarbodiimide (manufactured by Matsumoto Yushi Seiyaku Co., Ltd .; EN160)

[Impact resistance improver]
G-1: Core-shell type graft copolymer (core layer component: acrylic rubber, shell layer component: (meth) methyl acrylate polymer) (Rohm and Haas Co., Ltd .; Paraloid BPM-515)
G-2: Core-shell type graft copolymer (core layer component: silicone / acrylic rubber, shell layer component: polymer having a glycidyl group-containing vinyl unit) (Mitsubishi Rayon Co., Ltd .; Metabrene S-2200)
G-3: Core-shell type graft copolymer (core layer component: butadiene rubber, shell layer component: (meth) methyl acrylate polymer) (manufactured by Kaneka Corporation; Kane Ace B-564)
G-4: (meth) acrylic acid ester copolymer of ultra high molecular weight (manufactured by Mitsubishi Rayon Co., Ltd .; Methbrene P-531, weight average molecular weight 4.5 million)
G-5: Methyl methacrylate / n-butyl acrylate copolymer (manufactured by Kuraray Co., Ltd .; Clarity LA2140e, content of n-butyl acrylate 77 mass%)

Example 1
Polylactic acid resin (A-1), polycarbonate resin (B-1), and tin oxide (C-1) were used in amounts shown in Table 1, and these were dry blended to produce a twin screw extruder (TEM26SS type manufactured by Toshiba Machine Co., Ltd.). The melt was kneaded under the conditions of a barrel temperature of 190 ° C., a screw rotation speed of 150 rpm, and a discharge rate of 15 kg / h. After melt-kneading, a strand is extruded from a 0.4 mm diameter × 3 hole die, cut into a pellet, and is heated at a temperature of 60 ° C. with a vacuum dryer (trade name “Vacuum Dryer DP83” manufactured by Yamato Kagaku Co., Ltd.). The polylactic acid resin composition was obtained by drying for 48 hours.
The obtained polylactic acid-based resin composition is measured for general physical properties in accordance with ISO by setting the cylinder temperature to 160 to 200 ° C. and the mold temperature to 100 ° C. by using an injection molding machine (Nex-110 type, manufactured by Nissei Plastic Co., Ltd.). Test pieces (size; length × width × thickness: 80 mm × 10 mm × 4 mm) were prepared.

Examples 2-22, Comparative Examples 1-16
Except that various types and ratios of polylactic acid resin, polycarbonate resin, tin compound, methyl methacrylate copolymer, crystal nucleating agent and carbodiimide compound were changed as shown in Tables 1 to 3, the same as in Example 1. A polylactic acid resin composition was obtained.
The obtained polylactic acid-based resin composition was injection-molded in the same manner as in Example 1 to prepare a test piece for measuring general physical properties (size; length × width × thickness: 80 mm × 10 mm × 4 mm) in conformity with ISO. .

Example 23
A glass tube was charged with L-lactide and tin oxide (C-1) and heated to 150 ° C. in a nitrogen atmosphere. When the contents were melted, stirring was started, the internal temperature was further raised to 190 ° C. and polymerization (melt polymerization) was performed for 2 hours, and then the polymerization reaction product was taken out. The obtained polymerization reaction product is vacuum-dried at 130 ° C. for 30 hours to remove lactide remaining in the polymerization reaction product, and a polylactic acid resin composition containing tin oxide (C-1) in the polylactic acid resin. Got. The polylactic acid resin had a D-form content of 0.2 mol%, a weight average molecular weight of 115,000, and an MFR of 15.
Then, polycarbonate resin (B-1) was added to this polylactic acid resin composition, and in the same manner as in Example 1, melt-kneaded with a twin screw extruder, and the polylactic acid resin composition having the composition shown in Table 1 Got.
The obtained polylactic acid-based resin composition was injection-molded in the same manner as in Example 1 to produce ISO-compliant general physical property measurement test pieces (size: length × width × thickness: 80 mm × 10 mm × 4 mm). The sample was subjected to various measurements.

  Tables 1 to 3 show the compositions of the polylactic acid resin compositions obtained in Examples 1 to 23 and Comparative Examples 1 to 16.

Examples 24-41, Comparative Examples 17-31
The polylactic acid resin composition was the same as in Example 1 except that the types and ratios of the polylactic acid resin, polycarbonate resin, tin compound, methyl methacrylate copolymer and impact modifier were changed as shown in Table 4. I got a thing.
And the obtained polylactic acid-type resin composition was injection-molded similarly to Example 1, and the test piece (size; length x width x thickness: 80 mm x 10 mm x 4 mm) based on an ISO compliant general physical property measurement was carried out. Produced.

  Table 4 shows the compositions of the polylactic acid resin compositions obtained in Examples 24-41 and Comparative Examples 17-31.

As is clear from Tables 1 and 3, the polylactic acid resin compositions obtained in Examples 1 to 23 have a short molding cycle when obtaining molded articles, and the obtained molded articles are subjected to thermal deformation. The temperature was high and the heat resistance was excellent. Further, the obtained molded body had a high bending rupture strength retention rate, excellent wet heat durability, and excellent impact resistance. Among them, the smaller the D-form content of the polylactic acid resin (A), the shorter the molding cycle, and the more excellent the heat resistance could be obtained.
The polylactic acid-based resin compositions of Examples 15 to 19 and 23 were a combination of tin oxide (B) and an organic crystal nucleating agent. For this reason, crystallinity improved more and the shaping | molding cycle became shorter. Moreover, the obtained molded body was more excellent in heat resistance, and also had a high bending rupture strength retention and improved wet heat durability.
The polylactic acid resin compositions of Examples 20 to 22 were a combination of tin oxide (B), an organic crystal nucleating agent, and a carbodiimide compound. For this reason, the wet heat durability was greatly improved by these synergistic effects, and the obtained molded product had a high bending rupture strength retention after high temperature and high humidity treatment for 3000 hours.
Moreover, since the polylactic acid-type resin composition of Examples 24-41 was a thing which used the tin oxide and the impact resistance improving agent together clearly from Table 4, the molded object obtained from this resin composition was obtained. The impact resistance is greatly improved by the synergistic effect of the impact modifier and tin oxide.

  On the other hand, since the polylactic acid-based resin compositions of Comparative Examples 1, 3, 11 to 14 did not contain tin oxide (C), the crystal performance and wet heat durability of the polylactic acid resin could not be improved. The molding cycle was long, and the resulting molded product was inferior in both heat resistance and wet heat durability. Although the polylactic acid-based resin composition of Comparative Example 2 contained a crystal nucleating agent, tin oxide (C) was not contained, so the wet heat durability of the polylactic acid resin could not be improved. The obtained molded product was inferior in wet heat durability. Since the polylactic acid resin composition of Comparative Example 4 used tin powder as the tin compound, the crystal performance and wet heat durability of the polylactic acid resin could not be improved, and the obtained molded product had heat resistance and wet heat. The durability was inferior. Since the polylactic acid resin composition of Comparative Example 5 used stannous chloride as the tin compound, the resin was greatly decomposed during kneading and molding, and a molded product could not be obtained. Since the polylactic acid-based resin composition of Comparative Example 6 contained too much tin oxide, the dispersibility deteriorated, and the resulting molded article had a poor appearance such as a rough surface. Since the polylactic acid-based resin composition of Comparative Example 7 contained too much polylactic acid resin, the obtained molded product was inferior in wet heat durability.

  Since the polylactic acid-based resin compositions of Comparative Examples 8 to 10 used a polylactic acid resin having a D-form content outside the predetermined range, the crystal performance was inferior, the molding cycle was long, and the obtained molded article Was inferior in heat resistance and wet heat durability. The polylactic acid-based resin composition of Comparative Example 15 contained a carbodiimide compound and a crystal nucleating agent. However, since tin oxide (C) was not contained, the crystal performance of the polylactic acid resin was insufficiently improved. In addition, the obtained molded product was inferior in wet heat durability. The polylactic acid-based resin composition of Comparative Example 16 contained a carbodiimide compound and a crystal nucleating agent. However, the polylactic acid resin was inferior in crystal performance because the D-form content was outside the predetermined range. In addition, the molding cycle was long, and the obtained molded product was inferior in both heat resistance and wet heat durability.

The polylactic acid-based resin compositions of Comparative Examples 17 to 31 contained an appropriate amount of an impact resistance improver, but did not contain tin oxide, so the effect of improving impact resistance was not sufficient, and crystals The forming speed was slow, the molding cycle was long, and the resulting molded article was inferior in impact resistance and heat resistance.

Claims (5)

A resin composition comprising a polylactic acid resin (A) having a D-form content of 0 to 2.0 mol%, or 98.0 to 100 mol%, and a polycarbonate resin (B), The mass ratio of the polylactic acid resin (A) to the polycarbonate resin (B) is 20/80 to 80/20, and the tin oxide (C) is added in a total of 100 parts by mass of the polylactic acid resin (A) and the polycarbonate resin (B). The polylactic acid-type resin composition characterized by containing 0.005-10 mass parts with respect to this. Furthermore, the methyl methacrylate copolymer (D) is added in an amount of 0.1 to 100 parts by mass in total of the polylactic acid resin (A) and the polycarbonate resin (B).
The polylactic acid-based resin composition according to claim 1, comprising 20 parts by mass. Furthermore, the impact resistance improver (G) is contained, and the impact resistance improver (G) is 0.5 to 10 parts by mass with respect to 100 parts by mass in total of the polylactic acid resin (A) and the polycarbonate resin (B). The polylactic acid-type resin composition of Claim 1 or 2 containing. The polylactic acid resin composition according to any one of claims 1 to 3, wherein the polylactic acid resin (A) has a D-form content of 0 to 0.6 mol% or 99.4 to 100 mol%. object. A molded article comprising the polylactic acid resin composition according to claim 1.