WO2013186883A1

WO2013186883A1 - Poly(lactic acid) resin composition, method for producing molded article, molded article, and holder for electronic device

Info

Publication number: WO2013186883A1
Application number: PCT/JP2012/065147
Authority: WO
Inventors: 千尋竹内; 山本　広志; 斉藤　英一郎
Original assignee: パナソニック株式会社
Priority date: 2012-06-13
Filing date: 2012-06-13
Publication date: 2013-12-19
Also published as: CN104364319A

Abstract

Provided is a poly(lactic acid) resin composition that contains a poly(lactic acid) and can be formed into a molded article in which appearance defects are suppressed and which has a high molded article productivity and high durability. This poly(lactic acid) resin composition contains a poly(lactic acid) and a thermoplastic resin other than the poly(lactic acid). The proportion of the poly(lactic acid) in the poly(lactic acid) resin composition is 4 to 15 mass % inclusive. The degree of dispersion of the poly(lactic acid) is 4.0 or lower.

Description

Polylactic acid resin composition, method for producing molded product, molded product, and holder for electronic device

The present invention relates to a polylactic acid resin composition, a method for producing a molded article using the polylactic acid resin composition, a molded article formed from the polylactic acid resin composition, and an electronic device formed from the polylactic acid resin composition. For holders.

In recent years, an increase in the concentration of carbon dioxide in the atmosphere has been pointed out as a cause of global warming, and the need for carbon dioxide emission regulations on a global scale has been advocated. Causes of carbon dioxide generation include respiration of organisms, rot and fermentation by bacteria, etc., but the amount of carbon dioxide generated by combustion of substances derived from petroleum resources is large, and it is due to carbon dioxide in the current atmosphere It is no exaggeration to say that the temperature rise phenomenon is caused by economic activity that wasted oil resources after human revolution. Furthermore, petroleum resources are limited resources and are expected to be depleted in the future.

On the other hand, in recent years, the effective use of plant resources that absorb and fix carbon dioxide in the atmosphere during the growth process has attracted attention as a carbon-neutral material. When obtaining plant resources, carbon dioxide in the atmosphere is absorbed by plant vegetation, and attempts have been made to replace petroleum resources with these plant resources.

Also in the field of plastic materials, attempts are being made to switch from conventional materials based on petroleum to materials using biomass. Plastic materials using biomass initially attracted attention as biodegradable plastics, but recently they have been re-evaluated as carbon-neutral plant plastics and have been put into practical use in some areas. One type of typical plant plastic is polylactic acid resin. By injection-molding the polylactic acid resin composition, it is expected to obtain various molded articles such as an electronic device holder, an electronic device internal chassis component, an electronic device casing, and an electronic device internal component.

For example, Patent Document 1 discloses that polylactic acid resin is 5 to 75% by mass, ABS resin is 20 to 60% by mass, (meth) acrylic acid ester polymer is 2 to 10% by mass, and talc is 3 to 25% by mass. The composition containing is disclosed.

However, there is a problem that needs to be solved in view of substituting polylactic acid for a thermoplastic resin such as an ABS resin that has been widely used in the fields as described above. That is, when molding a polylactic acid resin composition, compared with molding of a thermoplastic resin such as ABS resin, curing shrinkage becomes large and dirt adheres to the mold, making continuous molding difficult. Or the like, the moldability is liable to deteriorate, and the molded product tends to have poor appearance such as sink marks and unevenness. Further, there is a problem that the durability of the molded product is lowered. These facts hinder the spread of polylactic acid.

Japanese Patent Publication No. 2011-6669

The present invention has been made in view of the above-described reasons, and contains polylactic acid, has good moldability, suppresses the appearance defect of the molded product, and further improves the durability of the molded product. A composition, a method for producing a molded product having a good appearance from the polylactic acid resin composition and forming a highly durable molded product with high productivity, and a good appearance formed from the polylactic acid resin composition; An object is to provide a molded article and a holder for electronic equipment with high durability.

The polylactic acid resin composition according to the first embodiment of the present invention contains polylactic acid and a thermoplastic resin other than polylactic acid, and the ratio of the polylactic acid is in the range of 4% by mass to less than 15% by mass. The degree of dispersion of the polylactic acid is 4.0 or less.

In the second form, in the first form, the polylactic acid has a weight average molecular weight of 7 million or more.

In the third form, in the first or second form, the ratio of the polylactic acid is in the range of 4 to 7% by mass.

In the fourth aspect, in any one of the first to third aspects, the thermoplastic resin contains an ABS resin.

In the fifth embodiment, in the fourth embodiment, the ABS resin contains an ABS resin regenerated from a used product.

In the sixth embodiment, in the fourth or fifth embodiment, the ABS resin contains a flame retardant ABS resin.

The polylactic acid resin composition according to the seventh embodiment further contains a polymethyl methacrylate resin in any one of the fourth to sixth embodiments.

In the eighth form, in the seventh form, the polylactic acid contains D-lactic acid units in a proportion of 8 to 15 mol%.

In the ninth embodiment, in the seventh embodiment, the polylactic acid is a polylactic acid that does not crystallize even when heated at 100 ° C. for 2 hours.

In the tenth embodiment, in any one of the fourth to ninth embodiments, the average particle diameter of the ABS resin is 0.3 μm or less.

In an eleventh aspect, in any one of the fourth to tenth aspects, a melt flow rate (220 ° C., 10 kg) defined by ISO 1133 of the ABS resin is 15 to 35 g / 10 minutes, and the ABS The Charpy impact strength (notched) specified by ISO 179 of the resin is 10 to 30 kJ / m ² .

The polylactic acid resin composition according to the twelfth aspect further contains a polycarbonate resin in any one of the fourth to eleventh aspects.

In a thirteenth aspect, in any one of the first to third aspects, the thermoplastic resin contains a polycarbonate resin.

The polylactic acid resin composition according to the fourteenth embodiment contains, in the thirteenth embodiment, an elastomer having an Na content of 15 ppm or less, a K content of 15 ppm or less, and an S content of 13 ppm or less in a proportion of 1% by mass or more. .

In the fifteenth form, in the fourteenth form, the pH of the elastomer is in the range of 6-8.

In a sixteenth aspect, in any one of the thirteenth to fifteenth aspects, the polycarbonate resin has a melt flow rate (300 ° C., 1.2 kg) as defined in ISO ASTM D1238 of 10 to 25 g / 10 min. It is a range.

The polylactic acid resin composition according to the seventeenth aspect further contains a flame retardant in any one of the thirteenth to sixteenth aspects.

According to an eighteenth aspect, in any one of the first to third aspects, the thermoplastic resin contains a polymethyl methacrylate resin.

In a nineteenth aspect, in any one of the first to third aspects, the thermoplastic resin contains a polypropylene resin.

In a twentieth aspect, in any one of the first to third aspects, the thermoplastic resin contains a low density polyethylene resin.

The polylactic acid resin composition according to the twenty-first aspect further comprises polybutylene adipate terephthalate and an organic peroxide in any one of the first to fourth aspects.

The polylactic acid resin composition according to the twenty-second aspect further contains a copolymer of alkyl methacrylate and alkyl acrylate in any one of the first to twenty-first aspects.

The polylactic acid resin composition according to the twenty-third form further contains a carbodiimide compound in any one of the first to twenty-second forms.

The polylactic acid resin composition according to the twenty-fourth form further contains a carbodiimide compound having no isocyanate group in the twenty-third form.

The polylactic acid resin composition according to the twenty-fifth aspect further contains a core-shell rubber in any one of the first to twenty-fourth aspects.

The polylactic acid resin composition according to the twenty-sixth aspect has a tensile strength retention of 80% or more when exposed in an atmosphere of 60 ° C. and 95% RH for 1000 hours in any one of the first to twenty-fifth aspects. Is formed. It is more preferable if a molded article having a tensile strength retention of 80% or more when exposed to an atmosphere of 60 ° C. and 95% RH for 3000 hours is formed.

In the method for producing a molded product according to the twenty-seventh aspect, the polylactic acid resin composition according to any one of the first to twenty-sixth aspects is prepared, and the polylactic acid resin composition is molded.

The molded product according to the twenty-eighth aspect is formed by molding the polylactic acid resin composition according to any one of the first to twenty-seventh aspects.

The molded product according to the twenty-ninth aspect has a tensile strength retention of 80% or more when exposed in an atmosphere of 60 ° C. and 95% RH for 1000 hours in the twenty-eighth aspect. More preferably, the tensile strength retention when exposed to an atmosphere of 60 ° C. and 95% RH for 3000 hours is 80% or more.

The electronic device holder according to the thirtieth embodiment is formed by molding the polylactic acid resin composition according to any one of the fourth to twelfth embodiments.

According to the present invention, while containing polylactic acid, the moldability is good, the appearance defect of the molded product is suppressed, and the durability of the molded product is further improved, the polylactic acid resin composition Manufacturing method of molded product for forming molded product with good appearance and high durability from product with good moldability, and molded product and electronic device holder with good appearance and high durability formed from said polylactic acid resin composition Is obtained.

It is a perspective view which shows the external appearance of the holder for electronic devices in one Embodiment of this invention.

[Ingredients in polylactic acid resin composition]
The polylactic acid resin composition according to the present embodiment contains polylactic acid and a thermoplastic resin other than polylactic acid. Further, the proportion of polylactic acid in the polylactic acid resin composition is in the range of 4 to 15% by mass, preferably in the range of 4 to 12% by mass, more preferably in the range of 4 to 10% by mass, particularly The range is preferably 4 to 7% by mass. And the dispersion degree of this polylactic acid is 4.0 or less. The polylactic acid preferably has a weight average molecular weight of 7 million or more.

Hereinafter, components that can be contained in the polylactic acid resin composition according to the present embodiment will be described in more detail.

(Polylactic acid)
The polylactic acid contained in the polylactic acid resin composition preferably has a weight average molecular weight (Mw) of 70,000 or more. In this case, the fluidity of the polylactic acid resin composition and the durability of the molded product become more suitable as an injection molding material. The degree of dispersion (Mw / Mn), which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), of this polylactic acid is 4.0 or less. Furthermore, the content of polylactic acid in the polylactic acid resin composition is in the range of 4 to 10% by mass, preferably in the range of 4 to 7% by mass.

By satisfying such conditions, an appropriate fluidity is imparted to the polylactic acid to ensure good moldability of the polylactic acid resin composition, and gas is hardly generated from the polylactic acid during molding. Thereby, sink marks and unevenness are less likely to occur in the molded product, and the appearance is improved. Further, even when the molded product is heated, it is difficult to cause appearance defects such as whitening. Furthermore, mold stains are less likely to occur during mold molding, so that the polylactic acid resin composition can be continuously molded and the mass productivity of the molded product is improved. Furthermore, despite the use of polylactic acid, the durability of the molded article is unlikely to decrease. In addition, this invention does not prevent that a polylactic acid resin composition contains a hydrolysis inhibiting agent from a viewpoint of a durable improvement. However, even if no hydrolysis inhibitor is used, the durability of the molded product is unlikely to decrease as described above. For this reason, it is also possible to obtain a molded article having good durability while reducing the production cost without using a hydrolysis inhibitor or suppressing the amount used.

Furthermore, by using polylactic acid, the content of the ABS resin in the polylactic acid resin composition is reduced, and accordingly, the proportion of unsaturated double bonds in the butadiene units in the ABS resin is also reduced. For this reason, it is expected that the light resistance of the molded product is improved.

Furthermore, from the viewpoint of substituting a thermoplastic resin such as an ABS resin with polylactic acid, in the present embodiment, a molding shrinkage rate when molding the polylactic acid resin composition and a thermoplastic resin such as an ABS resin are molded. The difference with the molding shrinkage at the time becomes small. For this reason, a polylactic acid resin composition is molded under the same conditions as in the case of molding a thermoplastic resin such as an ABS resin, using a molding die having the same structure as that for molding a thermoplastic resin such as an ABS resin. It becomes possible to do.

The weight average molecular weight of polylactic acid is more preferably in the range of 70,000 to 500,000, more preferably in the range of 70,000 to 300,000, and in the range of 70,000 to 100,000. Particularly preferred. Further, the polylactic acid dispersity (Mw / Mn) is preferably 4 or less, more preferably 3.5 or less, further preferably 3.0 or less, and further preferably 2.5 or less. preferable.

The weight average molecular weight (Mw) and number average molecular weight (Mn) of polylactic acid are calculated by converting the measurement results by gel permeation chromatography using hexafluoroisopropanol as a solvent (mobile phase) by a calibration curve using standard polystyrene. Calculated. In measuring the weight average molecular weight and number average molecular weight of polylactic acid, 0.036 g of polylactic acid was dissolved in 9 mL of HFIP (hexafluoroisopropanol) over 48 hours, and the resulting solution was filtered with a filter. A sample for measurement is obtained. When this sample is measured with a high-speed GPC device (model number HLC-8220) manufactured by Tosoh Corporation, the weight average molecular weight and number average molecular weight of polylactic acid are calculated based on the measurement result.

Examples of polylactic acid include a homopolymer of lactic acid and a copolymer of lactic acid and a hydroxycarboxylic acid other than lactic acid. Polylactic acid is obtained by polymerizing lactic acid. Lactic acid is obtained, for example, by fermenting starch derived from plants such as corn.

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 may be used alone or in combination of two or more.

The polylactic acid preferably contains at least one of poly-L-lactic acid, which is a polymer of L-lactic acid, and stereocomplex polylactic acid. In particular, when the polylactic acid is composed solely of stereocomplex type polylactic acid, or composed only of poly-L-lactic acid and stereocomplex type polylactic acid, it is a molded product with excellent appearance, water resistance, impact resistance and other properties. Is obtained.

Polylactic acid substantially consists of an L-lactic acid unit and a D-lactic acid unit represented by the following formula [Chemical Formula 1].

The poly-L-lactic acid is preferably composed of 90 to 100 mol%, more preferably 95 to 100 mol%, and still more preferably 99 to 100 mol% of L-lactic acid units. When the proportion of L-lactic acid units is high, the durability of the molded product is further improved. Examples of units other than L-lactic acid include D-lactic acid units and units other than lactic acid.

Polylactic acid may contain units other than lactic acid. 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.

Polylactic acid in which the proportion of D-lactic acid units is in the range of 8 to 15 mol% with respect to the total units (monomer units) constituting polylactic acid, poly which does not crystallize even when heated at 100 ° C. for 2 hours It is also preferable that the ratio of the lactic acid or D-lactic acid unit is in the range of 8 to 15 mol% with respect to all the units constituting the polylactic acid and the polylactic acid does not crystallize even when heated at 100 ° C. for 2 hours. . Whether or not polylactic acid is crystallized is confirmed from the measurement result by differential scanning calorimetry (DSC). When polylactic acid is crystallized, an endothermic peak due to melting is observed at around 160 ° C. by differential scanning calorimetry (DSC), but such an endothermic peak is not observed when it is not crystallized. Use of such polylactic acid is important for suppressing thermal shrinkage of the injection molded product. These polylactic acids have the property that crystallization is very difficult to proceed. For this reason, it becomes difficult for crystallization of polylactic acid to proceed in an injection-molded product formed from the polylactic acid resin composition, and therefore, thermal shrinkage of the injection-molded product due to crystallization of polylactic acid is greatly suppressed. The proportion of D-lactic acid units in the polylactic acid is preferably in the range of 8 to 15 mol%, more preferably in the range of 8 to 13 mol%, and further in the range of 8 to 12 mol% as described above. The range is preferable, and the range of 8.6 to 11.6 mol% is particularly preferable.

The ratio of D-lactic acid units in polylactic acid is measured by an optical rotation method. For example, a 1% by mass trichloromethane solution of polylactic acid to be measured is prepared, and the ratio of D-lactic acid units in the polylactic acid in this solution is measured by a digital polarimeter (for example, manufactured by SHANGHAI CHANGFANG OPTICAL INSTRUMENT CO., DLTD. , Model number WZZ-2S).

Polylactic acid is produced by a known method. For example, L- or D-lactide is produced by heating and ring-opening polymerization in the presence of a metal polymerization catalyst. Polylactic acid can also be produced by crystallizing a low molecular weight polylactic acid containing a metal polymerization catalyst, followed by solid phase polymerization by heating under reduced pressure or in an inert gas stream. Furthermore, polylactic acid is also produced by a direct polymerization method in which lactic acid is dehydrated and condensed in the presence / absence of an organic solvent.

The melt flow rate of polylactic acid (190 ° C., 2.16 kg) is preferably in the range of 1 to 16 g / 10 min. In this case, the moldability (fluidity) of the polylactic acid resin composition is particularly improved.

(ABS resin, PC resin, PMMA resin, PP resin, and LDPE resin)
Thermoplastic resins other than polylactic acid in the polylactic acid resin composition are ABS resin (acrylonitrile / butadiene / styrene copolymer resin), PC resin (polycarbonate resin), PMMA resin (polymethyl methacrylate resin), PP resin (polypropylene resin). ) Or LDPE resin (low density polyethylene resin).

(1) ABS resin Since the polylactic acid resin composition contains an ABS resin, the durability, dimensional stability, impact resistance, heat resistance, and moldability of the polylactic acid resin composition during molding are high. Become. Also, from the viewpoint of replacing the ABS resin with polylactic acid, the content of the ABS resin in the polylactic acid resin composition is reduced, and the proportion of unsaturated double bonds in the butadiene unit in the ABS resin is accordingly reduced. To do. For this reason, it is expected that the light resistance of the molded product is improved.

Commercially available products are appropriately used as the ABS resin. When an ABS resin is used, the content of the ABS resin in the polylactic acid resin composition is appropriately set, but it is preferably in the range of 20 to 97% with respect to the entire polylactic acid resin composition. The content of the ABS resin is set according to the kind of the thermoplastic resin in the polylactic acid resin composition when the polylactic acid resin composition contains a thermoplastic resin other than polylactic acid and the ABS resin. For example, depending on the type of thermoplastic resin in the polylactic acid resin composition, the ABS resin content is preferably in the range of 80 to 95% by mass, and preferably in the range of 20 to 80% by mass. The polylactic acid resin composition may contain only polylactic acid and ABS resin as the thermoplastic resin.

As the ABS resin, it is preferable to use a resin synthesized by a continuous bulk polymerization method (bulk polymerization) without using an emulsifier and a coagulant. The ABS resin synthesized by this method has few additional components at the time of synthesis, so that hydrolysis of the polylactic acid resin is hardly caused. Examples of such ABS resin include Santac AT-05 and Santac AT-08 manufactured by Nippon A & L Co., Ltd.

As the ABS resin, not only a virgin raw material but also an ABS resin regenerated from a used product may be used. As used products, various home appliances can be cited. ABS resin is widely used in home appliances and is suitable as a recycled material. When an ABS resin regenerated from a used product is used, the polylactic acid resin composition preferably contains a core-shell rubber as will be described later in order to improve the impact resistance of the molded product.

Further, the ABS resin may contain a flame retardant ABS resin containing a flame retardant. In this case, the flame retardancy of the molded product is improved. Examples of the flame retardant contained in the flame retardant ABS resin include tetrabromobisphenol A, antimony oxide, and triphenyl phosphate.

From the viewpoint of sufficiently improving the mechanical properties such as impact resistance of the molded product obtained by injection molding, the proportion of styrene units constituting the ABS resin is preferably 72% by mass or less, and more preferably 70% by mass or less. It is preferable that it is 62 mass% or less especially. Furthermore, the proportion of styrene units is preferably 40% by mass or more, more preferably 55% by mass or more, and particularly preferably 58% by mass or more. That is, the proportion of styrene units is preferably in the range of 40 to 72% by mass, more preferably in the range of 55 to 70% by mass, and still more preferably in the range of 58 to 62% by mass.

From the viewpoint of sufficiently suppressing welds and flow marks in the molded product obtained by injection molding, the proportion of the butadiene units constituting the ABS resin is preferably in the range of 16 to 23% by mass, and preferably 16 to 19% by mass. If it is a range, it is still more preferable.

The proportion of acrylonitrile units in the ABS resin depends on the proportion of styrene units and butadiene units, but is preferably in the range of 1.5 to 30% by mass, and more preferably in the range of 15 to 30% by mass. In particular, when the ABS resin is substantially composed only of acrylonitrile units, butadiene units, and styrene units, the ratio of acrylonitrile units is preferably in the range of 15 to 30% by mass.

The structural unit of the ABS resin may include a structural unit other than the acrylonitrile unit, the butadiene unit, and the styrene unit. For example, the structural unit of the ABS resin may include a methyl methacrylate unit.

The proportion of structural units such as acrylonitrile units, styrene units, butadiene units, and methyl methacrylate units in the ABS resin is measured by the NMR measurement results of the ABS resin, and the gradient polymer elution chromatography (GPEC) of the ABS resin. Derived based on the result.

The particle size of the ABS resin is not particularly limited, but it is preferable that the particle size is smaller from the viewpoint of maintaining a good appearance of the molded product over a long period of time. When the particle size of the ABS resin is small, the molded product is less likely to be whitened even if the molded product is exposed to a high temperature for a long period of time. Such suppression of whitening is considered to be due to the fact that the components in the molded product are finely dispersed due to the small particle size of the ABS resin and the squeeze effect is reduced. In order to sufficiently suppress whitening of the molded product, the average particle size of the ABS resin is preferably 0.4 μm or less, more preferably 0.35 μm or less, and particularly preferably 0.3 μm or less. preferable. The lower limit of the average particle diameter is not particularly limited, but is preferably 0.1 μm or more. This average particle size is a number-based arithmetic average particle size measured by dyeing ABS resin particles, photographing the particles with a transmission electron microscope (TEM), and analyzing the photographed image. is there. In the measurement of the average particle diameter, the particle diameter of the particles is an area equivalent diameter obtained by converting the projected area of the particles into a circle.

The melt flow rate (220 ° C., 10 kg) specified by ISO 1133 of ABS resin is preferably in the range of 15 to 35 g / 10 minutes. In this case, the moldability of the polylactic acid resin composition is further improved. Further, the Charpy impact strength (notched) defined in ISO 179 of ABS resin is preferably 10 to 30 kJ / m ² . Thereby, mechanical characteristics such as impact resistance of the molded product are further improved.

(2) PC resin When the polylactic acid resin composition contains a polycarbonate resin, the heat resistance and impact resistance of the molded product are improved.

When a polycarbonate resin is used, the content of the polycarbonate resin in the polylactic acid resin composition is appropriately set, but is preferably in the range of 20 to 97% with respect to the entire polylactic acid resin composition. The content of the polycarbonate resin is set according to the type of the thermoplastic resin in the polylactic acid resin composition when the polylactic acid resin composition contains a thermoplastic resin other than polylactic acid and the polycarbonate resin. For example, depending on the type of thermoplastic resin in the polylactic acid resin composition, the content of the polycarbonate resin is preferably in the range of 80 to 95% by mass, and preferably in the range of 20 to 80% by mass. The polylactic acid resin composition may contain only polylactic acid and a polycarbonate resin as the thermoplastic resin.

It is also preferred that the thermoplastic resin other than polylactic acid in the polylactic acid resin composition contains an ABS resin and further contains a polycarbonate resin. In this case, the heat resistance of the molded product is further improved. In this case, the content of the polycarbonate resin in the polylactic acid resin composition is appropriately set, but the mass ratio of the ABS resin to the polycarbonate resin in the polylactic acid resin composition is in the range of 99: 1 to 30:70. The range of 60:40 to 40:60 is more preferable, and the range of 55:45 to 45:55 is particularly preferable.

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, 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) diphenol, 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, etc. Is mentioned. A preferred dihydric phenol is bis (4-hydroxyphenyl) alkane, and bisphenol A 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 an aromatic polycarbonate resin is produced from a dihydric phenol and a carbonate precursor by an interfacial polymerization method, a catalyst, a terminal terminator, an antioxidant for the oxidation of the dihydric phenol, etc. are used as necessary. May be.

As polycarbonate resin, branched polycarbonate resin copolymerized with trifunctional or higher polyfunctional aromatic compound, polyester carbonate resin copolymerized with aromatic or aliphatic (including alicyclic) difunctional carboxylic acid, bifunctional A copolymer polycarbonate resin obtained by copolymerizing a functional alcohol (including an alicyclic), and a polyester carbonate resin obtained by copolymerizing the bifunctional carboxylic acid and the difunctional alcohol together may be used. Two or more kinds of polycarbonate resins may be used.

When a branched polycarbonate resin is used, the melt tension of the polylactic acid resin composition increases, thereby improving molding processability in extrusion molding, foam molding, blow molding and the like. As a result, a molded product having superior 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, phloroglucid, 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 proportion of the structural unit derived from the polyfunctional aromatic compound in the branched polycarbonate resin is 100% by mole in total 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 this 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.

As the polycarbonate resin, two or more kinds of polycarbonates having different dihydric phenol components, polycarbonates containing branched components, various polyester carbonates, polycarbonate-polyorganosiloxane copolymers, and the like may be used. Further, two or more kinds of polycarbonates having different production methods, polycarbonates having different end stoppers, and the like may be used.

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.

As the polycarbonate resin, not only virgin raw materials but also polycarbonate resins regenerated from used products, so-called material-recycled aromatic polycarbonates may be used. 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. Are preferred. These do not contain a large amount of additives or other resins, and the desired quality is easily obtained stably. In particular, an automobile headlamp lens, an optical recording medium, and the like are preferable as the preferred embodiment 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 polycarbonate resin is preferably 1 × 10 ⁴ to 5 × 10 ⁴ , more preferably 1.4 × 10 ⁴ to 3 × 10 ⁴ , and even 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 . The viscosity average molecular weight only needs to satisfy the entire polycarbonate resin, and a mixture of two or more polycarbonate resins having different molecular weights may satisfy this range.

In calculating the viscosity average molecular weight, first, the specific viscosity calculated by the following formula (a) was measured using an Ostwald viscometer for a sample solution prepared by dissolving 0.7 g of a polycarbonate resin in 100 ml of methylene chloride at 20 ° C. Obtained from measurement results. Next, the viscosity average molecular weight M is determined from the specific viscosity obtained using the following formulas (b) to (d).
Specific viscosity (ηSP) = (t−t0) / t (a)
[T0 is the drop time of methylene chloride, t is the drop time of the sample solution]
ηSP / 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)
The melt flow rate (300 ° C., 1.2 kg) defined by ISO ASTM D1238 of the polycarbonate resin is preferably in the range of 10 to 25 g / 10 minutes. In this case, the durability of the molded product is improved. The melt flow rate (1.2 ° C. at 300 ° C.) is preferably in the range of 10 to 20 g / 10 minutes.

(3) PMMA resin When the polylactic acid resin composition contains a polymethyl methacrylate resin (PMMA resin), the dimensional stability, impact resistance, and heat resistance of the molded product are improved. In addition, the transparency of the molded product is increased, and the weather resistance of the molded product is improved.

When the PMMA resin is used, the content of the PMMA resin in the polylactic acid resin composition is appropriately set, but is preferably in the range of 20 to 97% with respect to the entire polylactic acid resin composition. When the polylactic acid resin composition contains a thermoplastic resin other than polylactic acid and PMMA resin, the content of the PMMA resin is set according to the type of the thermoplastic resin in the polylactic acid resin composition. For example, depending on the type of thermoplastic resin in the polylactic acid resin composition, the content of the PMMA resin is preferably in the range of 80 to 95% by mass, and preferably in the range of 20 to 80% by mass. The polylactic acid resin composition may contain only polylactic acid and a PMMA resin as the thermoplastic resin.

Part or all of the polymethyl methacrylate resin (PMMA resin) may be a polymethyl methacrylate resin elastomer (PMMA resin elastomer).

In particular, when ABS resin and PMMA resin are used in combination, it is preferable that the PMMA resin has a notch Charpy impact value defined 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 notched Charpy impact value is not particularly limited.

It is preferable that the melt flow rate (230 ° C., 3.8 kg) of PMMA resin defined by ISO ASTM D1238 is 1.5 g / 10 min or more. Furthermore, the melt flow rate is preferably 5 g / 10 min or more. When the melt flow rate is 1.5 g / 10 min or more, the compatibility of the PMMA resin with polylactic acid is increased in the polylactic acid resin composition, thereby further improving the appearance of the molded product and improving the impact resistance. Further improvement.

Particularly when ABS resin and PMMA resin are used in combination, the weight average molecular weight of PMMA resin is preferably in the range of 60,000 to 80,000, and more preferably in the range of 65,000 to 75,000. . In this case, in the polylactic acid resin composition, the compatibility of the PMMA resin with the polylactic acid is increased, thereby further improving the appearance of the molded product and further improving the impact resistance. 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).

Specific examples of PMMA resin include Sumitomo Chemical Co., Ltd. trade name Sumipex HT03Y, Sumipex HT01X, and the like.

In particular, when an ABS resin and a PMMA resin are used in combination, the content of the PMMA resin in the polylactic acid resin composition is preferably 0.5% by mass or more, and more preferably 1% by mass or more. It is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass or less. In particular, the content of the PMMA resin in the polylactic acid resin composition is preferably in the range of 1 to 5% by mass. When the content is 1% by mass or more, the dimensional stability, impact resistance, and heat resistance of the molded product are particularly improved. In addition, when the content is 5% by mass or less, the high fluidity of the polylactic acid resin composition and the good appearance of the molded product are maintained by maintaining the proper fluidity of the polylactic acid resin composition. The durability of the product is less likely to decrease. The PMMA resin content is preferably in the range of 1 to 2% by mass.

In particular, when an ABS resin and a PMMA resin are used in combination, the polylactic acid has a ratio of “D-lactic acid units in the range of 8 to 15 mol% with respect to all units (monomer units) constituting the polylactic acid. "Polylactic acid", "Polylactic acid that does not crystallize even when heated at 100 ° C for 2 hours", or "D-lactic acid unit ratio is in the range of 8 to 15 mol% with respect to all the units constituting polylactic acid. In addition, “polylactic acid that does not crystallize even when heated at 100 ° C. for 2 hours” is particularly preferable. In this case, the crystallization of polylactic acid in the injection molded product is difficult to proceed. For this reason, the thermal shrinkage with time in the high temperature environment of the injection molded product is greatly suppressed. In addition, since there is no need to advance crystallization of polylactic acid during injection molding, the molding cycle is shortened and welds and flow marks are less likely to occur in the injection molded product. Further, the injection molded product has characteristics required for the molded product such as sufficiently high durability, impact resistance, heat resistance and the like. For this reason, the injection-molded product can be used in a wide range of fields such as the home appliance field, the building material, and the sanitary field, which are expected to be used for a long time. In this case, the content of the PMMA resin in the polylactic acid resin composition is preferably in the range of 0.5 to 10% by mass, and more preferably in the range of 2 to 10% by mass. When the content is 2% by mass or more, the dimensional stability, impact resistance, and heat resistance of the injection molded product are particularly improved. When the content is 10% by mass or less, the high fluidity of the polylactic acid resin composition is maintained, and the high moldability of the polylactic acid resin composition and the good appearance of the injection molded product are maintained. The content of the PMMA resin is preferably in the range of 1 to 5% by mass, and more preferably in the range of 1 to 2% by mass.

(4) PP resin When the polylactic acid resin composition contains a polypropylene resin, the specific gravity of the molded product is lowered, and weight reduction of the molded product can be expected. The content of the polypropylene resin in the polylactic acid resin composition is preferably in the range of 20 to 97% with respect to the entire polylactic acid resin composition.

(5) LDPE resin When the polylactic acid resin composition contains a low-density polyethylene resin, the electrical insulation properties of the molded article are improved. The content of the low density polyethylene resin in the polylactic acid resin composition is preferably in the range of 20 to 97% with respect to the entire polylactic acid resin composition.

(Carbodiimide compound)
The polylactic acid resin composition also preferably contains a carbodiimide compound such as a polycarbodiimide compound or a monocarbodiimide compound. In this case, these compounds react with some or all of the carboxyl group ends of polylactic acid to exert a blocking action, thereby further improving the durability of the molded product in a high-temperature and high-humidity environment.

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

As such a carbodiimide compound, a commercially available product can be used as appropriate. Specific examples of the carbodiimide compound include trade name carbodilite LA-1 (poly (4,4'-dicyclohexylmethanecarbodiimide)), carbodilite HMV-8CA, carbodilite HMV-15CA, etc., manufactured by Nisshinbo Chemical Co., Ltd.

It is preferable that the carbodiimide compound does not have an isocyanate group. That the carbodiimide compound does not have an isocyanate group means that the compound having an isocyanate group is not mixed in the carbodiimide compound. That is, in the carbodiimide compound, a compound having an isocyanate group may be mixed, but it is preferable that such a compound having an isocyanate group is not contained in the polylactic acid or the resin composition. In this case, the durability of the molded product is further improved. This is considered because the reactivity of an isocyanate group is too high compared with a carbodiimide group. That is, it is considered that the isocyanate group reacts and is consumed quickly in the molded product, and therefore, the function of blocking the carboxyl group terminal of polylactic acid is quickly lost.

Examples of the polycarbodiimide compound having no isocyanate group include trade name Carbodilite HMV-15CA manufactured by Nisshinbo Chemical Co., Ltd.

When a carbodiimide compound is used, the content of the carbodiimide compound in the polylactic acid resin composition is preferably in the range of 0.1 to 5% by mass. When the content is 0.1% by mass or more, the durability of the molded product is further improved, and when the content is 5% by mass or less, high mechanical strength of the molded product is maintained. The content of the carbodiimide compound is preferably 3% by mass or less. The content of the carbodiimide compound is particularly preferably in the range of 0.1 to 1.0% by mass, and more preferably in the range of 0.1 to 0.5% by mass.

When a carbodiimide compound is used, when the master batch is prepared by premixing only polylactic acid and a carbodiimide compound during the preparation of the polylactic acid resin composition, the above-mentioned action due to the use of the carbodiimide compound is particularly effective. Is demonstrated.

(Copolymer of alkyl methacrylate and alkyl acrylate)
The polylactic acid resin composition preferably also contains a copolymer of alkyl methacrylate and alkyl acrylate. In this case, mechanical properties such as impact resistance of the molded product are further improved.

Examples of the alkyl methacrylate include methyl methacrylate and ethyl methacrylate. Examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, butyl acrylate and the like. The polymerization molar ratio of alkyl methacrylate to alkyl acrylate is preferably in the range of 40:60 to 95: 5. The weight average molecular weight of the copolymer of alkyl methacrylate and alkyl acrylate is preferably in the range of 1 million to 5 million. 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).

As a specific example of such a copolymer of alkyl methacrylate and alkyl acrylate, trade name Metabrene P530 manufactured by Mitsubishi Rayon Co., Ltd. may be mentioned.

When a copolymer of alkyl methacrylate and alkyl acrylate is used, the content of the copolymer of alkyl methacrylate and alkyl acrylate in the thermoplastic resin composition is 0.5% by mass to 5% by mass. It is preferable to be within the range. When the content is 1.0% by mass or more and 3.0% by mass or less, the impact resistance of the molded product is particularly improved. The reason is that the melt viscosity of the thermoplastic resin composition is sufficiently increased within the above range, thereby forming an amorphous sea-island structure in the microstructure of the molded product, which leads to an improvement in impact resistance of the molded product. For this reason.

(Polybutylene adipate terephthalate)
The polylactic acid resin composition preferably further contains polybutylene adipate terephthalate. Polybutylene adipate terephthalate is a copolymer of 1,4-butanediol, adipic acid and terephthalic acid. Specific examples thereof include trade name Ecoflex manufactured by BASF.

When the polylactic acid resin composition contains polybutylene adipate terephthalate, the polylactic acid is cross-linked by polybutylene adipate terephthalate by the reaction between polylactic acid and polybutylene adipate terephthalate when the polylactic acid resin composition is molded. . This strengthens the structure in the molded product, and as a result, the durability and mechanical properties of the molded product are further improved.

When polybutylene adipate terephthalate is used, the content in the polylactic acid resin composition is preferably 0.1 to 10% by mass.

When the polylactic acid resin composition contains polybutylene adipate terephthalate, it is preferable that the polylactic acid resin composition further contains an organic peroxide. In this case, free radicals are generated from the organic peroxide when the polylactic acid resin composition is molded, so that the radical reaction between polylactic acid and polybutylene adipate terephthalate is promoted, and the durability and mechanical properties of the molded product are increased. The characteristics are further improved. As the organic peroxide, for example, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (trade name Perhexa 25B manufactured by NOF Corporation) is used. The content of the organic peroxide in the polylactic acid resin composition is not particularly limited, but is preferably 0.01 to 1% by mass, for example.

(Core shell rubber)
It is also preferable that the polylactic acid resin composition contains a core-shell rubber. In this case, mechanical properties such as impact resistance of the molded product are further improved. The core-shell rubber is a polymer having a multilayer structure, and an innermost layer (core layer) made of the polymer and one or more layers (shell layer) covering the core layer and made of a polymer different from the core layer. ). Examples of the core-shell rubber include a resin obtained by polymerizing a monomer such as a styrene monomer or a vinyl cyanide monomer in the presence of a rubbery polymer.

When the core-shell rubber is used, the content of the polylactic acid resin composition as a whole is not limited, but from the viewpoint of improving the durability of the molded product, this content is preferably 1% by mass or more, If it is 3 mass% or more, it is still more preferable. From the viewpoint of improving the flowability of the polylactic acid resin composition and improving the moldability, workability, handling, etc. of the polylactic acid resin composition, the content of the core-shell rubber is preferably 12% by mass or less.

The core shell rubber will be described in more detail.

Examples of the core shell rubber include Si-containing core shell rubber. When the core-shell rubber containing Si is used, the flame retardancy of the molded product is further improved. Examples of the core-shell rubber containing Si include polyorganosiloxane-containing graft copolymers and epoxy-modified silicone / acrylic rubber. As the epoxy-modified silicone / acrylic rubber, commercially available products can be used as appropriate. As a specific example, trade name Metabrene S2200 manufactured by Mitsubishi Rayon Co., Ltd., which is a core-shell structure containing glycidyl methacrylate in the shell, can be mentioned.

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.

When an unsaturated carboxylic acid alkyl ester-diene rubber-aromatic vinyl graft copolymer is used, the unsaturated carboxylic acid alkyl ester-diene rubber-aromatic vinyl graft copolymer is a core-shell rubber containing Si. All or a part of these functions can be exhibited instead of the core-shell rubber containing Si. 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, acrylonitrile-butadiene, and the like. 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 this unsaturated carboxylic acid alkyl ester-diene rubber-aromatic vinyl graft copolymer is methyl methacrylate-butadiene-styrene copolymer (MBS resin). The methyl methacrylate-butadiene-styrene copolymer is preferably a multilayer polymer comprising 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 formula [Chemical Formula 2]. 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 formula [Chemical Formula 3].

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. The emulsion polymerization method is particularly preferable. is there. 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 may be used as appropriate. Preferable specific examples of the methyl methacrylate-butadiene-styrene copolymer include trade names of Metabrene C-223A, Metabrene C-323A, Metabrene C-215A, Metabrene C-201A, and Metabrene C-202 manufactured by Mitsubishi Rayon Co., Ltd. Examples include METABLEN C-102, METABLEN C-140A, METABLEN C-132, etc., trade name Kane Ace M-600 manufactured by Kaneka Corporation, and trade name Paraloid EXL-2638 manufactured by Rohm & Haas Co., Ltd.

When the polylactic acid resin composition contains a polycarbonate resin, the polylactic acid resin composition further contains an elastomer having an Na content of 15 ppm or less, a K content of 15 ppm or less, and an S content of 13 ppm or less in a proportion of 1% by mass or more. It is preferable to contain. In this case, mechanical properties such as impact resistance of the molded product are further improved by the elastomer. In addition, when an elastomer having a small content of Na and K having a small atomic number and a small sulfur component is used, hydrolysis of polylactic acid is suppressed and discoloration of the polycarbonate resin is suppressed. If the elastomer contains a large amount of sulfur component, discoloration of the polycarbonate resin is promoted. Moreover, decomposition | disassembly of polycarbonate resin is also suppressed by using such an elastomer. For this reason, the durability of the molded product is further improved. The ratio of the elastomer in the polylactic acid resin composition is particularly preferably in the range of 2 to 9% by mass.

The Na content, K content, and S content of the elastomer are measured by fluorescent X-ray analysis. As the measuring device, for example, a fluorescent X-ray analyzer (product number XEPOS) manufactured by Spectro Corporation is used.

As such an elastomer, for example, a methyl methacrylate-butadiene-styrene copolymer (MBS resin) having a Na content of 15 ppm or less, a K content of 15 ppm or less, and an S content of 13 ppm or less is preferably used.

In addition, the pH of this elastomer is preferably in the range of 6-8. In this case, hydrolysis of polylactic acid is further suppressed. For this reason, the durability of the molded product is further improved.

The elastomer preferably has a functional group that reacts with an ester bond. In this case, the appearance of the molded product is improved. The reason is considered as follows. When a polycarbonate resin and polylactic acid are used in combination, the difference in fluidity between the two is usually large, so that a sea-island structure of polylactic acid and the polycarbonate resin is easily formed in the molded product. This sea-island structure causes flow marks in the molded product. However, when the elastomer has a functional group that reacts with an ester bond as described above, the polylactic acid is thickened, thereby reducing the difference in fluidity between the polylactic acid and the polycarbonate resin. For this reason, it is considered that the compatibility between the polylactic acid and the polycarbonate resin is improved, thereby improving the appearance of the molded product.

In addition, when such an elastomer is used, when the polylactic acid resin composition contains a flame retardant, it is possible to impart high flame retardancy to the molded product while reducing the ratio of the flame retardant. This is also considered to be because hydrolysis of polylactic acid is suppressed.

(Plant-derived PET)
It is also preferable that the polylactic acid resin composition contains PET (plant-derived PET) synthesized from a raw material including a plant-derived raw material. In such plant-derived PET, for example, terephthalic acid and monoethylene glycol containing monoethylene glycol (biomonoethylene glycol) produced from plant-derived ethanol such as sugar cane (so-called bioethanol) undergo dehydration condensation. Is synthesized.

By using such plant-derived PET, the amount of petroleum-derived resources used in the polylactic acid resin composition and its molded product is reduced, which makes it possible to reduce petroleum-derived resources, which is an environmental problem. Contribute to the solution.

The ratio of biomonoethylene glycol to the total monoethylene glycol in the plant-derived PET raw material is not particularly limited, but is preferably in the range of 1 to 100% by mass, and more preferably in the range of 5 to 100% by mass. For plant-derived PET, the ratio of biomonoethylene glycol to the total monoethylene glycol in the raw material is measured by ASTM D6866-11 METHOD B.

When plant-derived PET is used, the proportion of plant-derived PET in the polylactic acid resin composition is not particularly limited, but is preferably in the range of 1 to 30% by mass.

(Other thermoplastic resins)
In the polylactic acid resin composition, various thermoplastic resins other than the above may be contained. For example, the polylactic acid resin composition is made of polyethylene terephthalate resin (PET resin), polybutylene terephthalate resin (PBT resin), cyclohexanedimethanol copolymerized polyethylene terephthalate resin (so-called PET-G resin), polyethylene naphthalate resin, polybutylene naphthalate. Aromatic polyester resins such as resins; cyclic polyolefin resins; polycaprolactone resins; thermoplastic fluororesins typified by polyvinylidene fluoride resins; polyethylene resins, ethylene- (α-olefin) copolymer resins, etc. . 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. When these thermoplastic resins are used, the content thereof is preferably in the range of 3 to 12% by mass with respect to the polylactic acid resin composition.

(Antioxidant)
The polylactic acid resin composition preferably contains an antioxidant. In this case, the durability of the molded product is further improved by further suppressing hydrolysis of polylactic acid in the molded product. Antioxidants include 2,2-methylenebis- (4-methyl-6-tert-butylphenol), octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propanoate, and bis (3 It is preferable to use at least one selected from the group consisting of (t-butyl-4-hydroxy-5-methyl-phenyl) dicyclopentadiene.

(Fillers, etc.)
The polylactic acid resin composition may contain a filler. As the filler, for example, talc, wollastonite, mica, clay, montmon lilonite, smectite, kaolin, zeolite (aluminum silicate), anhydrous amorphous aluminum silicate obtained by subjecting zeolite to acid treatment and heat treatment, etc. An inorganic filler is mentioned. Talc and wollastonite are particularly preferable. Among these fillers, only one type may be used, or two or more types may be used in combination.

The average particle size of talc is usually preferably in the range of 0.1 to 10 μm. 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 not particularly limited, but is preferably in the range of 1 to 30% by mass. If this content is 1% by mass or more, the tensile modulus of the molded product is improved, and if this content is 30% by mass or less, the penetration of talc into the screw during kneading of the polylactic acid resin composition is suppressed. Thus, good workability and moldability are maintained. The talc content is preferably in the range of 1 to 15% by mass, more preferably in the range of 3 to 8% by mass. When this content is 8% by mass or less, the occurrence of welds and flow marks is sufficiently suppressed even when a molded product having a complicated shape is obtained, and when this content is 3% by mass or more, talc The effect of addition is particularly demonstrated.

The polylactic acid resin composition may contain a dye or a pigment as a colorant. As dyes, coumarin fluorescent dyes, benzopyran fluorescent dyes, perylene fluorescent dyes, anthraquinone fluorescent dyes, thioindigo fluorescent dyes, xanthene fluorescent dyes, xanthone fluorescent dyes, thioxanthene fluorescent dyes, thioxanthone fluorescent dyes , Thiazine fluorescent dyes, diaminostilbene fluorescent dyes, fluorescent dyes (including fluorescent brighteners); perylene dyes; coumarin dyes; thioindigo dyes; anthraquinone dyes; thioxanthone dyes; Peranone dyes; quinoline dyes; quinacridone dyes; dioxazine dyes; isoindolinone dyes; phthalocyanine dyes. Of the fluorescent dyes, coumarin fluorescent dyes, benzopyran fluorescent dyes, and perylene fluorescent dyes that have good heat resistance and little deterioration during molding of the polycarbonate resin are suitable. As the pigment, metallic pigments such as various plate fillers having a metal film or a metal oxide film, carbon, and the like can be used.

The content of the colorant in the polylactic acid resin composition is preferably 2% by mass or less and more preferably 1.5% by mass or less with respect to 100 parts by mass of the total amount of the resin components. Furthermore, the content of the colorant is preferably 0.00001 parts by mass or more, more preferably 0.00005 parts by mass or more, and 0.5 parts by mass or more with respect to 100 parts by mass of the total amount of the resin components. If it is more preferable.

(Flame retardants)
The polylactic acid resin composition preferably further contains a flame retardant. In this case, the flame retardancy of the molded product is improved. As the flame retardant, a Br flame retardant, an organic phosphorus flame retardant, or antimony oxide is preferably used. The content of the Br flame retardant in the polylactic acid resin composition is preferably 1 to 30% by mass, and the content of the organophosphorus flame retardant is preferably in the range of 1 to 30% by mass, A range of 3 to 12% by mass is more preferable. The content of antimony oxide is preferably 0.1 to 3% by mass. In such a range, the flame retardancy of the molded product formed from the polylactic acid resin composition is improved.

When the polylactic acid resin composition contains a polycarbonate resin and further contains an elastomer having an Na content of 15 ppm or less, a K content of 15 ppm or less, and an S content of 13 ppm or less in a proportion of 1% by mass or more, When the lactic acid resin composition further contains a flame retardant, the flame retardancy of the molded product is further improved. For this reason, even if there is little usage-amount of a flame retardant, high flame retardance is provided to a molded article. A desirable ratio of the flame retardant in this case is in the range of 5 to 10% by mass with respect to the total amount of the polylactic acid resin composition.

Such a molded product having high flame retardancy is suitable as a member for an electronic device such as a battery pack housing, a personal computer housing, and a multifunction device part.

As the organic phosphorus flame retardant, it is particularly preferable to use a cyclic phosphazene compound represented by the following [Chemical Formula 4].

R ¹ and R ² are each independently an aryl group or a (meth) acrylic acid ester group having an unsaturated bond at the terminal, and R ¹ and R ² may be the same or different. n is an integer of 3 to 25.

As the cyclic phosphazene compound represented by [Chemical Formula 4], an appropriate commercially available product may be used, for example, product numbers SPB100 and SPB100L manufactured by Otsuka Chemical Co., Ltd., trade name Ravitor FP-100 manufactured by Fushimi Pharmaceutical Co., Ltd. May be used.

The cyclic phosphazene compound represented by [Chemical Formula 4] is particularly preferably liquid. In this case, the dispersibility of the cyclic phosphazene compound in the polylactic acid resin composition is improved, and the flame retardancy of the molded product is particularly improved. Moreover, the flame retardance of a molded article can be improved while reducing the content of the cyclic phosphazene compound represented by [Chemical Formula 4]. In particular, as the cyclic phosphazene compound represented by the liquid [Chemical Formula 4], it is preferable to use a product number SPB100L manufactured by Otsuka Chemical Co., Ltd.

It is particularly preferable that part or all of the organophosphorus flame retardant in the polylactic acid resin composition is a cyclic phosphazene compound represented by [Chemical Formula 4]. In this case, the content of the cyclic phosphazene compound represented by [Chemical Formula 4] in the polylactic acid resin composition is preferably in the range of 1 to 30% by mass, and more preferably in the range of 3 to 12% by mass. .

Examples of organic phosphorus flame retardants other than the cyclic phosphazene compound represented by [Chemical Formula 4] include phosphate ester compounds represented by the following Formula [Chemical Formula 5]. When such a phosphoric ester compound is used, the flame retardancy of the molded product is greatly improved while maintaining high impact resistance of the molded product.

N in the formula [Chemical Formula 5] represents an integer of 0 to 5. The phosphate ester compound represented by the formula [Chemical Formula 5] may be a mixture of compounds having different n numbers. When the phosphate ester compound is a mixture as described above, the average n number is preferably 0.5 to 1.5, more preferably 0.8 to 1.2, and still more preferably 0.95 to 1.15. Particularly preferably, it is in the range of 1 to 1.14.

X in the above formula [Chemical Formula 5] represents a divalent group obtained by removing a hydroxyl group from a dihydroxy compound selected from the group consisting of hydroquinone, resorcinol, bisphenol A, and dihydroxydiphenyl. X is particularly preferably a divalent group derived from resorcinol, bisphenol A, or dihydroxydiphenyl.

In the above formula [Chemical Formula 5], R ¹ , R ² , R ³ , and R ⁴ each independently represents an aryl group having 6 to 12 carbon atoms. Specific examples of R ¹ , R ² , R ³ , and R ⁴ include monovalent groups derived from hydroxy compounds such as phenol, cresol, xylenol, isopropylphenol, butylphenol, and p-cumylphenol. Illustrated. Of these, R ¹ , R ² , R ³ , and R ⁴ are preferably a phenyl group or a 2,6-dimethylphenyl group.

In addition, this phenyl group may have a substituent having a halogen atom. Specific examples of the phosphate compound having a group derived from this phenyl group include tris (2,4,6-tribromophenyl) phosphate, tris (2,4-dibromophenyl) phosphate, and tris (4-bromophenyl). Examples include phosphate.

On the other hand, specific examples of the phosphate compound having a halogen atom and having no substituent include monophosphate compounds such as triphenyl phosphate and tri (2,6-xylyl) phosphate; resorcinol bisdi (2,6-xylyl) phosphate) A phosphate oligomer mainly composed of bisphenol A; a phosphate oligomer mainly composed of 4,4-dihydroxydiphenylbis (diphenylphosphate); a phosphate ester oligomer mainly composed of bisphenol A bis (diphenylphosphate) and the like are suitable. Here, “mainly” means that a small amount of other components having different degrees of polymerization may be included. More preferably, the component of n = 1 in the above formula [Chemical Formula 5] is 80% by mass or more, more preferably 85% by mass. % Or more, more preferably 90% by mass or more.

The acid value of the phosphate ester compound is preferably 0.2 mgKOH / g or less, more preferably 0.15 mgKOH / g or less, still more preferably 0.1 mgKOH / g or less, and particularly preferably 0.05 mgKOH / g. It is as follows. The lower limit of the acid value can be substantially 0, and is preferably 0.01 mgKOH / g or more practically. When the polylactic acid resin contains a phosphate ester compound represented by the formula [Chemical Formula 5] and having an acid value of 0.2 mgKOH / g or less, the thermal stability of the polylactic acid resin composition is particularly high, and the polylactic acid resin composition The hydrolysis resistance of the product is improved and the water resistance of the molded article is increased. The content of the half ester in the phosphate ester compound is more preferably 1.1% by mass or less, and still more preferably 0.9% by mass or less. As a minimum, 0.1 mass% or more is preferable practically, and 0.2 mass% or more is more preferable. When the acid value exceeds 0.2 mg KOH / g, or when the half ester content exceeds 1.5 mg, the thermal stability at the time of molding becomes inferior, and the polylactic acid resin composition accompanying the decomposition of the aromatic polycarbonate The hydrolysis resistance of the product decreases.

Specific examples of such phosphate ester compounds include product number PX202 manufactured by Daihachi Chemical Industry Co., Ltd.

The organophosphorous flame retardant is a compound represented by the following structural formula (1-1) (resorcinol dixylenyl phosphate) and a structural formula (1-2) shown below as a phosphoric ester compound represented by [Chemical Formula 5]. It is preferable to contain at least one of the compounds (bisphenol A bis (diphenyl phosphate)).

In particular, when the organic phosphorus compound contains a compound represented by the structural formula (1-1), not only the flame retardancy of the molded product is improved, but also the heat resistance and durability of the molded product are improved.

As an organic phosphorus flame retardant other than the cyclic phosphazene compound represented by [Chemical Formula 4], ammonium phosphate may also be mentioned. As a specific example of ammonium phosphate, product number AP422 manufactured by Clariant Japan Co., Ltd. may be mentioned. Even when such an ammonium phosphate is used, the flame retardancy of the molded product is greatly improved while maintaining high impact resistance of the molded product.

(Fluorine-containing anti-dripping agent)
The polylactic acid resin composition preferably further contains a fluorine-containing anti-dripping agent. The fluorine-containing anti-drip agent is used in order to prevent melting and dropping at the time of combustion of the molded product and further improve the flame retardancy.

The content of the fluorine-containing anti-dripping agent in the polylactic acid resin composition is preferably in the range of 0.2 to 3% by mass, and more preferably in the range of 0.2 to 1% by mass. In such a range, it is possible to achieve both high mechanical strength and high flame resistance of the molded product.

As the fluorine-containing anti-drip agent, polytetrafluoroethylene (PTFE) having fibril forming ability is preferably used. PTFE having a fibril-forming ability has a very high molecular weight and tends to form a fibrous form by bonding PTFE to each other by an external action such as shearing force. The number average molecular weight determined from the standard specific gravity of PTFE is preferably in the range of 1 million to 10 million, and more preferably in the range of 2 million to 9 million. This PTFE may be in solid form or in the form of an aqueous dispersion. A PTFE mixture may be constituted by mixing PTFE with other resins for the purpose of improving dispersibility and further improving flame retardancy and mechanical properties of the molded product. Examples of commercially available PTFE having fibril forming ability include Teflon (registered trademark) 6J manufactured by Mitsui DuPont Fluorochemical Co., Ltd., and Polyflon MPA FA500, F-201L manufactured by Daikin Chemical Industries, Ltd. Commercially available PTFE aqueous dispersions include Asahi IC Fluoropolymers' Fullon AD-1, AD-936, Daikin Industries, Ltd., Fullon D-1, D-2, Mitsui DuPont Fluorochemical Co., Ltd. A typical example is Teflon (registered trademark) 30J manufactured by the company.

Examples of commercially available PTFE in a mixed form include “Metablene A3800” (trade name) manufactured by Mitsubishi Rayon Co., Ltd. and “BLENDEX B449” (trade name) manufactured by GE Specialty Chemicals.

In the case of PTFE in a mixed form, the proportion of PTFE in 100% by mass of the PTFE mixture is preferably 1 to 60% by mass, more preferably 5 to 55% by mass. When the ratio of PTFE is in the above range, good dispersibility of PTFE can be achieved.

It is preferable that the particle diameter of PTFE is small. In this case, the dispersibility of PTFE in the polylactic acid resin composition is improved, thereby further improving the durability and flame retardancy of the molded product. In particular, the average particle size of PTFE is preferably in the range of 20 to 100 μm. The average particle diameter of this PTFE is a value measured by ASTM D4895.

(Other)
As long as the polylactic acid resin composition does not contradict the purpose of the present invention and does not impair the effect thereof, the stabilizer, the ultraviolet absorber, the lubricant, the release agent, the plasticizer, the antistatic agent, the inorganic and the You may contain well-known additives, such as an organic type antibacterial agent. These additives 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.

[Polylactic acid resin composition and molded product]
The polylactic acid resin composition is prepared by mixing and kneading the raw materials of the polylactic acid resin composition as described above by an arbitrary method. In the mixing and kneading, for example, a twin screw extruder, a Banbury mixer, a heating roll, or the like is used. Among them, melt kneading using a twin screw extruder is preferable.

For example, in preparing a polylactic acid resin composition, a method of supplying the raw materials of the polylactic acid resin composition independently to a melt kneader represented by a vent type twin screw extruder, or a part of the raw materials was premixed Thereafter, a method of supplying to the melt kneader independently of the remaining components may be employed. Moreover, after supplying a part of raw material to a melt kneader, the method of supplying the remaining raw material from the middle of a melt extruder may be employ | adopted. The heating temperature at the time of melt kneading is appropriately set according to the composition of the polylactic acid resin composition, but is preferably in the range of 200 to 260 ° C.

In addition, when a raw material has a liquid component, what is called a liquid injection apparatus, a liquid addition apparatus, etc. may be used at the time of supply of the liquid component to a melt extruder.

The polylactic acid resin composition may be formed into pellets as necessary. For example, a polylactic acid resin composition extruded by a melt extruder is directly cut and pelletized, or after a strand of the polylactic acid resin composition is formed, the strand is cut by a pelletizer or the like and pelletized. Thus, a pellet-shaped polylactic acid resin composition may be obtained.

As a molding method of the polylactic acid resin composition, an appropriate molding method such as injection molding, rotational molding, blow molding, vacuum molding or the like can be adopted. In particular, injection molding is preferred. In injection molding, not only ordinary molding methods, but also injection compression molding, injection press molding, gas-assisted injection molding, foam molding (including the method of injecting supercritical fluid), insert molding, in-mold coating molding, bicolor Molding, sandwich molding, ultra-high speed injection molding, or the like may be employed.

In the injection molding of the polylactic acid resin composition, an appropriate injection molding apparatus can be used. In particular, in order to control the cavity surface temperature of the mold at the time of injection, it is preferable to use a mold having an electric heater. In this case, when the polylactic acid resin composition is injected, the temperature of the cavity surface is accurately and quickly adjusted by an electric heater.

The molded product obtained in this way can be used in a wide range of fields such as home appliances, building materials, and sanitary, which are expected to be used for a long time.

As described above, sink marks and unevenness are less likely to occur in the molded product according to the present embodiment, and thus the appearance is improved. Further, even when the molded product is heated, it is difficult to cause appearance defects such as whitening. Furthermore, when a molded product is formed by mold molding, mold contamination is less likely to occur, so that mass productivity of the molded product is high. Furthermore, despite the use of polylactic acid, the durability of the molded article is unlikely to decrease.

It is preferable that a molded product having a tensile strength retention of 80% or more when exposed to an atmosphere of 60 ° C. and 95% RH for 1000 hours is formed by molding the polylactic acid resin composition. More preferably, a molded article having a tensile strength retention of 80% or more when exposed to an atmosphere of 60 ° C. and 95% RH for 3000 hours is formed. That is, it is preferable that the retention rate of the tensile strength when the molded article formed from the polylactic acid resin is exposed for 1000 hours in an atmosphere of 60 ° C. and 95% RH is 80% or more. More preferably, the molded article has a tensile strength retention of 80% or more when exposed to an atmosphere of 60 ° C. and 95% RH for 3000 hours. The tensile strength retention is the ratio of the tensile strength of the molded article after the exposure treatment under the above conditions to the tensile strength of the molded article before the exposure treatment under the above conditions. Tensile strength is measured according to ISO 179.

The use of the molded product is not particularly limited. For example, when the molded product is formed from a polylactic acid resin composition containing an ABS resin, a particularly preferable specific example of the molded product is a holder for an electronic device such as a mobile phone. And internal components such as an internal chassis component in an electronic device such as a mobile phone, and a housing for electronic devices such as an outer casing. When the molded product is formed from a polylactic acid resin composition containing a PC resin, particularly preferred specific examples of the molded product include in-vehicle components, electronic components, home appliance housings, and the like. When the molded article is formed from a polylactic acid resin composition containing a PMMA resin, particularly preferred specific examples of the molded article include home appliance parts and electronic parts. When the molded product is formed from a polylactic acid resin composition containing a PP resin, specific examples of the molded product include in-vehicle interior parts, home appliance parts, and tableware applications. When the molded article is formed from a polylactic acid resin composition containing an LDPE resin, a particularly preferred specific example of the molded article is a blood sugar level puncture needle.

FIG. 1 shows a holder 2 for an electronic device as an example of a molded product 1 formed from a polylactic acid resin composition containing an ABS resin. The electronic device holder 2 has a function of holding and fixing an electronic device such as a mobile phone on a desktop or the like, or further has a function as a charger for charging a battery in the electronic device. In the electronic device holder 2, a region (mounting region 3) on which the electronic device is placed and a holding rib 4 protruding from the outer edge of the placement region 3 are formed. The electronic device placed on the placement region 3 is further supported by the holding rib 4, whereby the electronic device is held and fixed to the electronic device holder 2. For this reason, the electronic device holder 2 is formed to match the shape and dimensions of the electronic device. The electronic device holder 2 is not limited to such a structure, and may have an appropriate structure capable of holding the electronic device. For this purpose, the electronic device holder 2 is formed to match the shape and dimensions of the electronic device.

The molded product may be subjected to various surface treatments. Surface treatment includes forming a new layer on the surface of the molded product, such as vapor deposition (physical vapor deposition, chemical vapor deposition, etc.), plating (electroplating, electroless plating, hot dipping, etc.), painting, coating, printing, etc. Is mentioned. Specific examples of the surface treatment include hard coat, water / oil repellent coat, ultraviolet absorption coat, infrared absorption coat, metalizing (evaporation, etc.) and the like.

[Production Example 1]
The mixture of L-lactide and D-lactide is reacted by heating in a reactor equipped with a stirring blade in a nitrogen atmosphere in the presence of a metal polymerization catalyst and alcohol, and then the pressure in the reactor is reduced to remain in the mixture. Lactide was removed. Furthermore, polylactic acid was prepared by chipping this mixture. In preparing this polylactic acid, polylactic acid D and polylactic acid F having the composition described later were prepared by changing the blending ratio of L-lactide and D-lactide.

[Production Example 2]
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 (manufactured by Nature Works LLC, trade name: NatureWorks 4042D, optical purity 95% or higher, melting point 150 ° C., weight average molecular weight 210,000), twin screw extruder of 32 mm diameter (Coperion, ZSK 32) was used, and melt kneading was performed under conditions of a cylinder temperature of 200 ° C. to 250 ° C. and a rotation speed of 200 rpm to obtain a stereocomplex polylactic acid. The resulting stereocomplex polylactic acid had a melting point of 213 ° C. and a stereogenicity of 100%.

[Examples and Comparative Examples]
For each Example and Comparative Example, the components shown in the following table 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.

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 80 ° 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 70 ° C. and injection molding was performed to obtain a molded product.

[Molding cycle evaluation]
For each example and comparative example, a single-point gate mold was used during injection molding of the resin composition, and the dimensions of the molded product were 60 mm × 60 mm × 2 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.

[Evaluation of appearance and mold contamination]
For each example and comparative example, a single-point gate mold was used during injection molding of the resin composition, and the dimensions of the molded product were 60 mm × 60 mm × 2 mm. In each example and comparative example, 100 samples were tested.

The presence or absence of wrinkles and sink marks in this sample was confirmed, and the number of molded products (number of defects) in which wrinkles or sink marks had occurred was confirmed.

Furthermore, the presence or absence of welds and flow marks in the center of the sample was confirmed, and the number of samples (number of defects) in which welds or flow marks were observed was confirmed.

Furthermore, every time a sample was molded, the presence or absence of mold contamination was confirmed, and the number of times mold contamination was observed was confirmed.

[Color development evaluation]
In each Example, carbon black (carbon black MA600B manufactured by Mitsubishi Chemical Corporation) was blended at a ratio of 1 part by mass with respect to 100 parts by mass of the total amount of raw material components shown in the following table when the composition was prepared.

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 A, the case of 11 to 15 as B, and the case of 16 or less as C.

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

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

[Durability evaluation]
(Durability A)
After the molded products obtained in each of the examples and comparative examples were exposed to an atmosphere of 60 ° C. and 95% RH for 3000 hours, the tensile strength of the molded products was measured according to ISO 179. The ratio (tensile strength retention ratio) of the molded product after the exposure treatment to the tensile strength of the molded product before the exposure treatment was derived, and this was used as an index of durability.

(Durability B)
The molded products obtained in each Example and Comparative Example were exposed to an atmosphere of 75 ° C. and 80% RH for 3000 hours, and then the tensile strength of the molded products was measured according to ISO 179. The ratio (tensile strength retention ratio) of the molded product after the exposure treatment to the tensile strength of the molded product before the exposure treatment was derived, and this was used as an index of durability.

(Durability C)
The molded products obtained in each Example and Comparative Example were exposed to an atmosphere of 60 ° C. and 95% RH for 1000 hours, and then the tensile strength of the molded products was measured according to ISO 179. The ratio (tensile strength retention ratio) of the molded product after the exposure treatment to the tensile strength of the molded product before the exposure treatment was derived, and this was used as an index of durability.

[Appearance after 80 ° C treatment]
The molded article was subjected to a treatment for 48 hours in an atmosphere at 80 ° C. The appearances of the molded product before treatment and the molded product after treatment were visually observed and compared.

As a result, A was evaluated when no change was observed in the appearance, and B was evaluated when whitening occurred on the surface of the molded product after the treatment.

[Flame retardance]
The flame retardant class was evaluated by performing a combustion test according to UL94 on the molded product. The following table shows the thickness of the molded article subjected to the test and the flame retardance class.

[Post-shrinkage]
The molded article was subjected to a treatment for 48 hours in an atmosphere at 80 ° C. 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.

{(Ba) / b} × 100 (%)
[Evaluation results]
The result of the above evaluation test is shown in the following table together with the blending composition in each example and comparative example.

In addition, according to the said result, when polycarbonate resin was used, when the ratio of the elastomer A was 1 mass% or more, the external appearance evaluation became especially favorable. This is considered to be because the compatibility between the polylactic acid and the polycarbonate resin was improved because the elastomer A has a functional group that reacts with an ester bond.

Moreover, in each Example, the holder for electronic devices which has the external shape shown in FIG. 1 was formed by injection-molding the resin composition. Thereby, the holder for electronic devices with a favorable external appearance was obtained.

Details of each component shown in the table are as follows.
Polylactic acid A: manufactured by Nature Works LLC, trade name: NatureWorks 3001D, D-lactic acid unit ratio 1.5 mol%, weight average molecular weight 64,000, number average molecular weight 26,000, dispersity 2.5.
Polylactic acid B: manufactured by Nature Works LLC, trade name: NatureWorks 4032D, D-lactic acid unit ratio of 1.9 mol%, dispersity of 4.0 or less.
Polylactic acid C: manufactured by Nature Works LLC, trade name: NatureWorks 4060D, D-lactic acid unit ratio 11.5 mol%, weight average molecular weight 86,000, number average molecular weight 21,000, dispersity 4.1.
Polylactic acid D: polylactic acid obtained in Production Example 1, ratio of D-lactic acid unit 1.9 mol%, weight average molecular weight 75,000, number average molecular weight 31,000, dispersity 2.4, ISO Melt flow rate as defined in ASTM D1238 (190 ° C. 2.16 kg) 5.0 g / 10 min.
Polylactic acid E: Stereocomplex polylactic acid obtained in Production Example 2, weight average molecular weight 98,000, number average molecular weight 36,000, dispersity 2.7.
Polylactic acid F: Polylactic acid obtained in Production Example 1, ratio of L-lactic acid unit of 99.7 mol% or more, weight average molecular weight 109000, number average molecular weight 44,000, dispersity 2.4.
Polylactic acid G: Polylactic acid obtained in Production Example 1, D-lactic acid unit ratio 11.6 mol%, weight average molecular weight 92,000, number average molecular weight 25,000, dispersity 3.4.
Plant-derived PET: 18% of plant-derived MEG content, sold by Toyota Tsusho Corporation, trade name EastPET PW1, ASTM D6866-11.
PBAT: polybutylene adipate terephthalate.
ABS resin A: acrylonitrile unit ratio 20.5% by mass, styrene unit ratio 69% by mass, butadiene unit ratio 10.5% by mass, synthetic product by bulk polymerization, average particle size 0.46 μm, melt specified by ISO 1133 The flow rate (220 ° C., 10 kg) is 32 g / 10 minutes, and the Charpy impact strength (notched) specified in ISO 179 is 14 kJ / m ² .
ABS resin B: 22% by mass of acrylonitrile unit ratio, 58% by mass of styrene unit, 18% by mass of butadiene unit, synthetic product by emulsion polymerization, average particle size 0.30 μm, ISO
The melt flow rate (220 ° C. 10 kg) specified in 1133 is 29 g / 10 min, and the Charpy impact strength (notched) specified in ISO 179 is 21 kJ / m ² .
ABS resin C: acrylotolyl unit ratio 24% by mass, styrene unit ratio 62% by mass, butadiene unit ratio 14.5% by mass, synthetic product by emulsion polymerization, average particle size 0.30 μm, melt flow rate specified by ISO 1133 (220 ° C., 10 kg) is 16 g / 10 min, and Charpy impact strength (with notch) specified in ISO 179 is 15 kJ / m ² .
-Recycled ABS resin A: ABS resin recovered from household electrical appliance waste.
Recycled ABS resin B: A mixture of ABS resin A (50% by mass) and recycled ABS resin A (50% by mass).
Flame retardant ABS resin A: Acrylonitrile unit ratio 15 mass%, styrene unit ratio 43 mass%, butadiene unit ratio 15 mass%, tetrabromobisphenol A 17% mass%, antimony oxide 6% mass%, synthetic product by emulsion and bulk polymerization Average particle size 0.10 and 0.30 μm.
Flame retardant ABS resin B: manufactured by Daicel Polymer Co., Ltd., VF512, flammability UL-94 1.5 mm thickness V-2, melt flow rate (220 ° C. 10 kg) defined by ISO 1133 is 35 g / 10 min, ISO 179 The Charpy impact strength (with notch) specified in Table 1 is 18 kJ / m ² .
Flame retardant ABS resin C: manufactured by Daicel Polymer Co., Ltd., VF790, flammability UL-94 1.7 mm thickness, V-2, melt flow rate (220 ° C. 10 kg) defined by ISO 1133 is 26 g / 10 min, ISO179 The Charpy impact strength (with notch) specified in Table ² is 20 kJ / m ² .
Polycarbonate ABS resin: product number PX10 manufactured by Toray Industries, Inc.
Polycarbonate resin A: Melt flow rate specified in ISO ASTM D1238 (300 ° C., 1.2 kg) 15 g / 10 min, load deflection temperature specified in ISO 306, 128 ° C.
Polycarbonate resin B: Melt flow rate (300 ° C., 1.2 kg) defined by ISO ASTM D1238 22 g / 10 min, load deflection temperature defined by ISO 306, 128 ° C.
PMMA1: Polymethylmethacrylate, melt flow rate (230 ° C. 3.8 kg) 16 g / 10 min as specified in ISO ASTM D1238, load deflection temperature 78 ° C. as specified in ISO 306.
PMMA2: Polymethylmethacrylate, melt flow rate (230 ° C., 3.8 kg) defined by ISO ASTM D1238, 1.8 g / 10 min, deflection temperature under load defined by ISO 306, 87 ° C.
Polypropylene resin: Prime Polymer Co., Ltd., product number J-466HP.
Low density polyethylene resin: Asahi Kasei Chemicals Corporation, part number Suntec LD.
Carbodiimide compound A: Carbodiimide compound having an isocyanate group, poly (4,4′-dicyclohexylmethanecarbodiimide), carbodiimide equivalent 248, carbodiimide group: isocyanate group molar ratio 15: 2, LA-1 manufactured by Nisshinbo Chemical Co., Ltd.
Carbodiimide compound B: Carbodiimide compound having no isocyanate group, carbodiimide equivalent 262, Nisshinbo Chemical Co., Ltd., HMV-15CA.
Elastomer A: Core shell rubber (MBS resin) having a functional group that reacts with ester, pH 7.1, electric conductivity 47 mS / m, Na content 15 ppm, K content 15 ppm, S content 13 ppm.
Elastomer B: Core shell rubber (MBS resin), pH 6.0, electric conductivity 7 mS / m, Na content 15 ppm, K content 15 ppm, S content 13 ppm.
-Elastomer C: Copolymer of alkyl methacrylate and alkyl acrylate, trade name Metabrene C223A manufactured by Mitsubishi Rayon Co., Ltd., pH 4.6, electric conductivity 47 mS / m, Na content 95 ppm, K content 85 ppm, S Content 1610ppm.
PTFEA: polytetrafluoroethylene, average particle size 470 μm, apparent density 470 g / l, manufactured by Mitsui DuPont Fluorochemical Co., Ltd., product number PTFE 6-J.
PTFEB: polytetrafluoroethylene, average particle size 28 μm, melting point 327 ° C.
Organic peroxide: trade name Perhexa 25B manufactured by Nippon Oil & Fat Co., Ltd.

In calculating the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polylactic acid, 0.036 g of polylactic acid is first dissolved in 9 mL of HFIP (hexafluoroisopropanol) over 48 hours, and thereby obtained. A sample for measurement was prepared by filtering the solution through a filter. This sample was measured with a high-speed GPC apparatus (model number HLC-8220) manufactured by Tosoh Corporation using hexafluoroisopropanol as a mobile phase. The measurement results were converted by a calibration curve using standard polystyrene, and the weight average molecular weight (Mw) and number average molecular weight (Mn) of polylactic acid were calculated.

The average particle size of the ABS resin is the arithmetic average particle size based on the number. The ABS resin particles dyed with the dye are photographed with a transmission electron microscope (model number H-7650, manufactured by Hitachi, Ltd.), and the image is imaged. It derived | led-out by carrying out an image analysis process using the analyzer (the Nicole Corporation make, Luzex AP). In deriving the average particle diameter, the particle diameter of the particles is equal to the diameter of a circle having the same area as the projected area of the particles.

Claims

Containing polylactic acid and a thermoplastic resin other than polylactic acid,
The ratio of the polylactic acid is in the range of 4% by weight to less than 15% by weight
A polylactic acid resin composition, wherein the polylactic acid has a degree of dispersion of 4.0 or less.
The polylactic acid resin composition according to claim 1, wherein the polylactic acid has a weight average molecular weight of 7 million or more.
The polylactic acid resin composition according to claim 1 or 2, wherein the ratio of the polylactic acid is in the range of 4 to 12% by mass.
The polylactic acid resin composition according to claim 1, wherein the thermoplastic resin contains an ABS resin.
The polylactic acid resin composition according to claim 4, wherein the ABS resin contains an ABS resin regenerated from a used product.
The polylactic acid resin composition according to claim 4, wherein the ABS resin contains a flame-retardant ABS resin.
The polylactic acid resin composition according to claim 4, further comprising a polymethyl methacrylate resin.
The polylactic acid resin composition according to claim 7, wherein the polylactic acid contains 8 to 15 mol% of D-lactic acid units.
The polylactic acid resin composition according to claim 7, wherein the polylactic acid is polylactic acid that does not crystallize even when heated at 100 ° C. for 2 hours.
The polylactic acid resin composition according to claim 4, wherein the average particle diameter of the ABS resin is 0.3 μm or less.
The melt flow rate (220 ° C., 10 kg) specified by ISO 1133 of the ABS resin is 15 to 35 g / 10 minutes, and the Charpy impact strength (notched) specified by ISO 179 of the ABS resin is 10 to 30 kJ / The polylactic acid resin composition according to claim 4, which is m 2 .
The polylactic acid resin composition according to claim 4, further comprising a polycarbonate resin.
The polylactic acid resin composition according to claim 1, wherein the thermoplastic resin contains a polycarbonate resin.
The polylactic acid resin composition according to claim 13, comprising an elastomer having a Na content of 15 ppm or less, a K content of 15 ppm or less, and an S content of 13 ppm or less in a proportion of 1% by mass or more.
The polylactic acid resin composition according to claim 14, wherein the elastomer has a pH of 6 to 8.
The polylactic acid resin composition according to claim 13, wherein the polycarbonate resin has a melt flow rate (300 ° C, 1.2 kg) as defined in ISO ASTM D1238 in the range of 10 to 25 g / 10 minutes.
The polylactic acid resin composition according to any one of claims 13 to 16, further comprising a flame retardant.
The polylactic acid resin composition according to claim 1, wherein the thermoplastic resin contains a polymethyl methacrylate resin.
The polylactic acid resin composition according to claim 1, further comprising polybutylene adipate terephthalate and an organic peroxide.
The polylactic acid resin composition according to claim 1, further comprising a copolymer of an alkyl methacrylate and an alkyl acrylate.
The polylactic acid resin composition according to claim 1, further comprising a carbodiimide compound.
The polylactic acid resin composition according to claim 21, wherein the carbodiimide compound does not have an isocyanate group.
The polylactic acid resin composition according to claim 1, further comprising a core-shell rubber.
The polylactic acid resin composition according to claim 1, wherein a molded article having a tensile strength retention of 80% or more when exposed to an atmosphere of 60 ° C. and 95% RH for 3000 hours is formed.
The manufacturing method of the molded article which shape | molds the polylactic acid resin composition of Claim 1.
A molded article formed by molding the polylactic acid resin composition according to claim 1.
27. The molded article according to claim 26, which has a tensile strength retention of 80% or more when exposed to an atmosphere of 60 ° C. and 95% RH for 1000 hours.
The holder for electronic devices formed by shape | molding the polylactic acid resin composition of Claim 4.