JP5581962B2 - Copolymer resin composition, molded article, and method for producing copolymer resin composition - Google Patents

Description

  The present invention relates to a copolymer resin composition, a molded article using the copolymer resin composition, and a method for producing the copolymer resin composition.

  With the recent increase in awareness of global environmental problems, technological development has been actively carried out to reduce bioavailability and use of fossil resources. One such movement is to replace the raw material of plastics made from petroleum with biomass materials.

  Many resin parts are used for machine parts, particularly electrophotographic equipment such as copying machines and laser printers, image output equipment using inkjet technology, electrical and electronic equipment such as home appliances, and interior parts of automobiles. Most of these resin parts are made from plastics made from petroleum. However, because of the problems of reducing carbon dioxide emissions, the problem of exhaustion of petroleum resources, the problem of non-biodegradable plastics, etc. It is desired.

  Biomass resources mean that living organisms such as plants and animals and their products are used as resources. In addition to conventional raw materials such as wood, cotton, silk, wool, and natural rubber, corn It refers to starch, fats and oils, raw garbage, etc. obtained from soybeans and animals. Biomass resource-derived resins are made from these biomass resources as raw materials, and are generally often biodegradable resins. A biodegradable resin is a resin that is decomposed by microorganisms under predetermined temperature and humidity conditions in a natural environment. The biodegradable resin may be a petroleum-derived resin instead of a biomass resource-derived resin, but most existing petroleum-derived resins are non-biodegradable.

  Biodegradable resins derived from biomass resources are produced by chemical polymerization using lactic acid (abbreviated as LA) produced by fermenting carbohydrates obtained from potato, sugarcane, corn, etc. as raw materials. Polylactic acid (abbreviated as PLA), esterified starch composed mainly of esterified starch, polyhydroxyalkanoate (PolyHydoroxy Alkanoate; PHA) Abbreviations), 1,3-propanediol obtained by fermentation, and polytrimethylene terephthalate (abbreviated as PTT) using petroleum-derived terephthalic acid as a raw material are known. . Polybutylene succinate (Poly Butylene Succinate; abbreviated as PBS), which uses butanediol and succinic acid as raw materials, is currently produced from petroleum-derived raw materials, but it can be transferred to biomass-derived resins. Research has been conducted, and in the future, production of succinic acid, which is one of the main raw materials, from plants will be studied.

Among the above biomass resource-derived resins, polylactic acid (PLA) has a high melting point of around 180 ° C., is relatively excellent in molding processability, and has a stable supply to the market. Has been put to practical use. However, polylactic acid has a low glass transition temperature of around 56 ° C., and accordingly has a problem that its heat distortion temperature is around 55 ° C., which is unsuitable for applications requiring heat resistance. Since polylactic acid is a crystalline resin, it has an Izod impact strength of ² kJ / m ² or less and cannot be used for applications requiring impact resistance. For this reason, it has been considered difficult to employ a durable member such as a casing of an electrical / electronic device product in which a large amount of resin products are used.

  As a measure for improving the physical properties of polylactic acid, a method of forming a polymer alloy with a polycarbonate resin which is a petroleum resin is known. However, in order to ensure the physical properties necessary for the molded product, it is necessary to include a relatively large proportion of petroleum resin, and the proportion of biomass resource-derived resin can only be around 50%, and carbon dioxide emissions Environmental impact reduction effects such as reduction and oil consumption reduction will be halved.

  As another measure for improving the physical properties of polylactic acid, a technique for improving the heat resistance by promoting the crystallization of polylactic acid using the fact that polylactic acid is a crystalline resin has been studied. As methods for promoting crystallization, there are known a method of increasing the crystallinity by reheating (annealing) after molding, and a method of molding by adding a crystallization nucleating agent. In the method of annealing after molding, in addition to the disadvantage that the processing process becomes complicated and the molding time becomes long, it is necessary to install an annealing die to prevent deformation of the molded product due to crystallization, which is costly. There was a problem with productivity.

  As for the method of adding the crystallization nucleating agent, various crystallization nucleating agents that improve the degree of crystallization and the crystallization speed are being developed. Requires a crystallization time of about 2 minutes and cannot be molded with the same molding cycle time as that of petroleum-based general-purpose resins, and there is a problem in productivity.

  Also, since polylactic acid is crystallized at a temperature of about 100 to 110 ° C., it is necessary to adjust the mold temperature of 100 ° C. or more at the time of molding, and an inexpensive water-cooled mold temperature controller cannot be used. There was a problem of an increase in molding cost. Furthermore, in a molded product in which only polylactic acid is crystallized, even if it is sufficiently crystallized by annealing or the like, the deflection temperature under high load (load 1.80 MPa) is around 55 ° C., and the heat resistance is insufficient. The problem remains.

  On the other hand, microbially produced polyhydroxyalkanoate (PHA) resin having excellent heat resistance, such as a conventionally known hydroxybutyric acid-hydroxyvaleric acid copolymer, is likely to undergo thermal decomposition during heating, and injection molding, etc. In the case of producing a molded product by the above processing method, a decrease in physical properties due to thermal decomposition is a problem. It has been difficult for polyhydroxyalkanoate resins to suppress a decrease in molecular weight due to thermal decomposition even when conventional heat stabilizers, antioxidants and hydrolysis inhibitors are added.

  Below, the specific literature regarding the manufacture of biodegradable resin from the biomass resource-derived resin is introduced.

  Cited Document 1 and Cited Document 2 propose a method of improving the deflection temperature and impact resistance of a resin by blending about half of a resin made from petroleum resources such as polycarbonate resin to polylactic acid resin. . For example, in Cited Document 1, 20 to 80 parts by mass of polylactic acid, 20 to 70 parts by mass of polycarbonate, 0.1 to 50 parts by mass of reinforcing material, and 0.5 to 35 parts by mass of flame retardant The member for electronic devices characterized by including by is disclosed. Also, in Cited Document 2, an acrylic resin unit or a styrene resin unit is added to a polylactic acid resin of 95 to 5% by weight, an aromatic polycarbonate resin of 5 to 95% by weight, and a total of 100 parts by weight of these resins. A resin composition is disclosed in which 0.1 to 50 parts by weight of a flame retardant is blended with 1 to 50 parts by weight of a polymer compound graft-polymerized.

  In addition, as described in Cited Document 3 and Cited Document 4, by adding a biomass-based filler such as paper dust, wood powder, and natural fiber to the polylactic acid resin, the mechanical strength of the resin composition is increased. Can be improved. If this method is used, the constituent ratio of the biomass material can be increased without using a petroleum-derived resin. For example, Cited Document 3 proposes a housing material characterized by kneading a natural fiber impregnated with a flame retardant and at least a plant resource-derived resin, and the kenaf fiber is used as the natural fiber. A fiber selected from the group consisting of hemp fiber and jute fiber is disclosed.

  In Cited Document 4, an electric / electronic component formed by molding a resin composition obtained by blending 1 to 350 parts by weight of an organic filler derived from a natural product with respect to 100 parts by weight of a resin derived from plant resources is proposed. ing. The plant resource-derived resin is a polylactic acid resin, the organic filler derived from a natural product is at least one selected from paper powder or wood powder, and 50% by weight or more of the paper powder is waste paper powder. . In addition, it is described that the crystallinity of the polylactic acid resin can be increased by adding a crystallization nucleating agent or a plasticizer as a crystallization accelerator in order to improve the heat resistance of the polylactic acid resin. Yes.

In Patent Document 5, among the biodegradable polyesters, the formula [—CHR—CH ₂ —CO—O—] (wherein R is an alkyl group represented by C _n H _{2n + 1} , n Is an integer of 1 to 15), the crystallization speed of an aliphatic polyester polymer (Poly-3-Hydoroxy Alkanoate; P3HA) consisting of repeating units represented by the following formula is accelerated, injection molding, film molding, blow molding, We have proposed biodegradable polyester resin compositions with improved processability and processing speed in forming processes such as fiber spinning, extrusion foaming and bead foaming. The proposed biodegradable polyester resin composition is a mixture of P3HA produced from microorganisms and a crystallization nucleating agent comprising at least one selected from polyvinyl alcohol (PVA), chitin, and chitosan. , PVA, chitin or chitosan are said to be suitable crystallization nucleating agents for P3HA. As specific aliphatic polyester-based polymers, poly-3-hydroxybutyrate (P3HB) and (3-hydroxybutyrate (3HB)) / (3-hydroxyhexanoate (3HHx)) copolymers Is disclosed.

  Patent Document 6 proposes an optical polylactic acid resin composition comprising a polylactic acid resin, a polyhydroxyalkanoate copolymer, and a carbodiimide compound. This optical polylactic acid resin composition has excellent transparency and improved tensile properties, and contains 99.9-80 parts by weight of polylactic acid resin and 0.1-20 parts by weight of polyhydroxyalkanoate copolymer To do.

  In Patent Document 7, a lactic acid polymer and a hydroxyalkanoic acid polymer are contained for the purpose of increasing the biodegradability of a lactic acid polymer, which is a biodegradable resin, and improving moldability. An aliphatic polyester polymer blend is proposed. This aliphatic polyester polymer blend has high biodegradability, improved moldability, and excellent molded product characteristics.

Patent Document 8 proposes a heat resistant resin composition containing polylactic acid and an aliphatic polyester other than polylactic acid and containing crystalline SiO ₂ as a crystalline inorganic filler component. This heat resistant resin composition comprises (a1) 75-25% by mass of polylactic acid and (a2) 25-75% by mass of aliphatic polyester having a melting point other than polylactic acid of 100-250 ° C. The crystalline inorganic filler component (B) containing 10% by mass or more of crystalline SiO ₂ with respect to the component (A) is 0.1 to 70 parts by mass with respect to 100 parts by mass of the polymer composition component (A). Contains. This heat-resistant resin composition can be injection-molded at a mold temperature equal to or lower than the glass transition temperature (Tg) or near room temperature (0 to 60 ° C.), and has a high crystallization speed and a high degree of crystallization in the molding process. It is sufficiently high, and therefore has excellent heat resistance, has a property that the polymer component hardly deteriorates during use, and does not easily become brittle. In specific examples, a resin composition using polybutylene succinate (PBS) is disclosed. As a method for producing an aliphatic polyester, a dehydration polycondensation method, or an indirect polymerization in which a cyclic dimer is melt-polymerized is disclosed. Chemical polymerization methods such as a combination method and a ring-opening polymerization method in which a cyclic dimer is melt-polymerized in the presence of a catalyst are shown.

  In Patent Document 9, a lactic acid series comprising a mixture (A) of polylactic acid (a1) and aliphatic polyester (a2), and a mixture of polylactic acid segment and aliphatic block copolyester (B) having an aliphatic polyester segment. A resin composition is proposed. This lactic acid-based resin composition is excellent in moldability, flexibility and safety, and is biodegradable after use and easy to dispose of waste. In this lactic acid-based resin composition, the aliphatic polyester (a2) is polybutylene succinate and / or polycaprolactone, and a two-component mixture (A) composed of polylactic acid (a1) and aliphatic polyester (a2), Compatibilized with a two-component aliphatic block copolyester (B).

  Even if blending about half of a petroleum-derived resin such as polycarbonate resin with polylactic acid resin to improve heat resistance and mechanical strength, the effect of replacing resin products with biomass materials from the viewpoint of global environmental measures Will be halved. In addition, due to the future trend of exhaustion of crude oil, the price of petroleum-derived resin used in blending increases, and there is a possibility that the petroleum-derived resin cannot be used substantially.

  If a method using a natural organic material filler such as paper powder, wood powder, natural fiber or the like is used for the polylactic acid resin, the composition ratio of the biomass material can be increased and a resin composition using almost no petroleum resources can be obtained. However, for example, in the case of paper dust, wood powder, and natural fiber used in Citation 4, the size is about 1 to 10 mm, and paper dust, wood powder, natural fiber, and the like are raised on the surface of the resin component. In addition, it cannot be used for molded products that require high appearance accuracy and aesthetics, such as exterior casings of electrical products. In addition, in order to improve the appearance accuracy and aesthetics, in order to make paper powder, wood powder, and natural fiber fine powder, the production cost increases.

In order to improve the heat resistance of polylactic acid resin, it is necessary to increase the crystallization degree, but in order to increase the crystallization degree, a crystallization nucleating agent or a plasticizer as a crystallization accelerator is added. How to do is known. However, it is known that even when the crystallinity of the polylactic acid resin is increased in this way, the deflection temperature under high load (for example, 1.80 MPa) can be improved only to about 55 ° C. Furthermore, in order to crystallize polylactic acid, a high mold temperature and a long molding time are required. For example, in molding a tensile test piece having a thickness of 3 mm, a mold temperature is 100 ° C., and a molding cycle time is 90 to 100. It takes seconds. With conventional fossil resource-derived resins (for example, polypropylene and polystyrene), the molding of the same tensile test piece has a mold temperature of about 50 ° C. and a molding cycle time of about 30 seconds at most. This is a big problem for industrial production of resin molded products.

  On the other hand, as a polyalkanoate resin that does not contain lactic acid, use of a biodegradable resin having 3-hydroxybutyric acid (abbreviated as 3HB) or 3-hydroxyvaleric acid (abbreviated as 3HV) as a monomer unit is considered. It has been. Among these, 3-hydroxybutyric acid-3hydroxyvaleric acid copolymer (polyhydroxybutyrate-hydroxyvalerate copolymer) can be produced by microbial fermentation from a medium using glucose as a substrate, and is an alternative to polylactic acid resin. It is expected as a complementary resin such as a product or a blend to a polylactic acid resin. However, the 3-hydroxybutyric acid-3hydroxyvaleric acid copolymer is easily decomposed by heat, and there is a problem that the physical properties deteriorate due to decomposition in a molding process such as injection molding. This problem cannot be solved by increasing the molecular weight of the copolymer, adding a crystallization nucleating agent, blending with a polylactic acid resin, or the like.

  In the biodegradable polyester resin composition described in Patent Document 5, the crystallization temperature is as high as 110 ° C. in the molding of the specifically disclosed biodegradable polyester resin composition (see Patent Document 5). 4), it is difficult to adjust the temperature of the mold to about 90 ° C. or less of the upper limit temperature of the water-cooled temperature controller. Further, an amorphous portion remains even at a molding time of 40 seconds, and it is considered that crystallization does not proceed sufficiently. In addition, polyhydroxybutyrate and polyhydroxybutyrate-hydroxyvalerate copolymer have problems such as a significant decrease in molecular weight during heat processing and a decrease in strength of the resin molded product.

  Since the polylactic acid resin composition disclosed in Patent Document 6 is a transparent material for optical use, it is solidified in an amorphous state and is not crystallized. It is considered that the heat resistance is not sufficient. If presumed from the disclosed configuration, the heat resistance of the polylactic acid resin composition is presumed to be about 55 ° C. to 60 ° C., which is around the glass transition point of polylactic acid.

  The aliphatic polyester-based polymer blend disclosed in Patent Document 7 is a polymer blend of an aliphatic polyester containing a polyethylene glycol chain in the main chain and poly-3-hydroxybutyric acid (P3HB) as a specific configuration. . However, it does not contain a crystallization nucleating agent, and it is considered that problems remain in improving heat resistance, lowering the molding temperature, and shortening the molding time.

  In the heat resistant resin composition proposed in Patent Document 8, further improvement in heat resistance is desired. Moreover, examination of the resin manufacturing method by microbial treatment is waited regardless of chemical treatment in superposition | polymerization.

  In the lactic acid resin composition proposed in Patent Document 9, in order to improve the compatibility of the mixture (A) of polylactic acid (a1) and aliphatic polyester (a2), a polylactic acid segment and an aliphatic polyester segment are used. An aliphatic block copolyester (B) having the following formula is used. For this reason, it is necessary to select the composition and molecular structure of the aliphatic block copolyester (B).

  As mentioned above, economically usable general-purpose resins that can use biomass raw materials and have biodegradability are still under development. In particular, a resin composition having a heat resistance exceeding 60 ° C. that could not be achieved with polylactic acid and excellent in moldability and having impact strength that can be used for general-purpose molded products has not been obtained. Most of the biomass-based resin compositions that can be used in practice are those in which a petroleum-based resin is blended with polylactic acid to improve physical properties, and a resin kneading step is required. Biomass-derived polyester resins often have poor thermal decomposition characteristics, and in the kneading process of two or more kinds of resins, there is a problem that physical properties are easily deteriorated by applying shear stress for a long time at a high temperature. Furthermore, in resin blending, blending techniques that stabilize physical properties are required due to changes in the compatibility of the resins and differences in crystallization temperature.

  The object of the present invention is based on the above-mentioned problems, and has a biodegradable biomass-based copolymer resin composition having excellent heat resistance and impact resistance, and a molded article using the copolymer resin composition, and It is providing the manufacturing method of a copolymer resin composition.

  The copolymer resin composition of the present invention includes a lactic acid copolymer (referred to as copolymer A) containing monomer units represented by the following chemical formulas [1], [2], and [3]. It contains a polyester copolymer (referred to as copolymer B) containing monomer units represented by the following chemical formulas [1] and [2].

化学式［１］で表されるモノマーユニットは、３ヒドロキシ酪酸（３ヒドロキシブタン酸；３ＨＢと略称することがある。）のヒドロキシル基とカルボキシル基が結合手となったモノマーユニットである。同様に、化学式［２］で表されるモノマーユニットは、３ヒドロキシ吉草酸（３ヒドロキシペンタン酸；３ＨＶと略称することがある。）のヒドロキシル基とカルボキシル基が結合手となったモノマーユニットである。化学式［３］で表されるモノマーユニットは、乳酸（２ヒドロキシプロピオン酸；ＬＡと略称することがある。）のヒドロキシル基とカルボキシル基が結合手となったモノマーユニットである。

The monomer unit represented by the chemical formula [1] is a monomer unit in which a hydroxyl group and a carboxyl group of 3hydroxybutyric acid (3hydroxybutanoic acid; sometimes abbreviated as 3HB) are a bond. Similarly, the monomer unit represented by the chemical formula [2] is a monomer unit in which a hydroxyl group and a carboxyl group of 3hydroxyvaleric acid (3hydroxypentanoic acid; sometimes abbreviated as 3HV) become a bond. . The monomer unit represented by the chemical formula [3] is a monomer unit in which a hydroxyl group and a carboxyl group of lactic acid (2 hydroxypropionic acid; sometimes abbreviated as LA) become a bond.

  The three monomer units 3HB, 3HV, and LA in the copolymer A may be randomly arranged or may be arranged with regularity, but the copolymerized polyester of 3HB and 3HV A block copolymer in which an LA polymer block is added to the block can be preferably used. The 3HB and 3HV copolymer polyester block is preferably produced by a fermentation method. A block copolymer obtained by addition polymerization of lactic acid to a 3HB and 3HV copolymer polyester block produced by a fermentation method is a lactic acid monomer unit. It is suitable as a raw material resin for molded articles that is easy to control the composition ratio and arrangement, is relatively easy to adjust the molecular weight, and has excellent heat resistance and mechanical strength.

  The two monomer units of 3HB and 3HV in the copolymer B may also be randomly arranged or arranged with regularity, but are preferably produced by a fermentation method, The 3HB and 3HV copolyesters produced by the fermentation method are more preferably arranged at random because the molecular weight can be adjusted relatively easily and the production yield can be increased.

  In the copolymer A in the present invention, the content of the lactic acid monomer unit represented by the chemical formula [3] is 50 to 97 mol%, preferably 50 to 95 mol%. When the content of the lactic acid monomer unit in the copolymer A is less than 50 mol%, the molecular weight retention rate of the copolymer A with respect to the heat treatment tends to decrease, and heat is generated by heat treatment during kneading or molding as the resin composition. It tends to cause decomposition and molecular weight reduction. Moreover, when the content rate of a lactic acid monomer unit exceeds 97 mol%, it will become the property of a polylactic acid resin, and the heat resistance at the time of making a molded article will be inferior.

  The polyester copolymer (copolymer B) in the present invention comprises a 3-hydroxybutyric acid monomer unit and a 3-hydroxyvaleric acid monomer unit, and the monomer unit in the copolymer B with the ratio of the 3hydroxyvaleric acid monomer unit as the monomer unit. The content is 10 to 25 mol%, preferably 10 to 20 mol%. The copolymer B is preferably a polyester copolymer produced by a microbial fermentation method.

  In the copolymer resin composition according to the present invention, the copolymer A and the copolymer B are mixed at a predetermined ratio, for example, 99: 1 to 60:40, preferably 97: 3 to 70:30. Yes. When the mixing ratio of the copolymer A and the copolymer B is in the range of 99: 1 to 60:40, an excellent improvement effect of the impact resistance of the copolymer resin composition can be obtained, and the heat resistance And the thermal decomposition retention rate (molecular weight retention rate) can be maintained high.

  The heat resistance of the copolymer resin composition of the present invention was evaluated based on the deflection temperature under load at 1.80 MPa. The deflection temperature under load was measured according to JIS K 7191-2 (1996), and a strip test piece having a length of 130 mm, a width of 3.2 mm, and a height of 12.7 mm was prepared from the copolymer resin composition by injection molding. (The strip test piece may be annealed after molding.) This was measured at a fulcrum distance of 100 mm, a heating rate of 2 ° C./min, and a bending stress of 1.80 MPa (Method A) of 65 ° C. or more. It is desirable to be.

  Generally, general-purpose resin molded products can be used for a wide range of applications as long as the above-mentioned deflection temperature under load is 65 ° C. to 100 ° C., and in particular, it is sufficient as a molded product as a casing for electric / electronic devices. Heat resistance. However, in the conventional polylactic acid resin, it is not easy to set the deflection temperature under load to 65 ° C. or higher by annealing, addition of a crystallization nucleating agent, or the like.

  The lactic acid copolymer (copolymer A) in the copolymer resin composition of the present invention has a heat stabilizer and / or water in the copolymer resin composition even when the content of lactic acid monomer units is less than 50 mol%. If a decomposition inhibitor is contained, a certain degree of thermal stability can be exhibited if not sufficient.

  Even when the content of the lactic acid monomer unit in the copolymer A is 50 to 95 mol%, it is preferable to contain a heat stabilizer and / or a hydrolysis inhibitor. The copolymer resin composition of the present invention contains a heat stabilizer and / or a hydrolysis inhibitor, so that the heat stability is further high, and sufficient heat stability against heat treatment during molding such as injection molding. Can keep. For this reason, there is no significant decrease in molecular weight during thermal processing, such as in polyhydroxybutyrate and polyhydroxybutyrate-hydroxyvalerate copolymer, which are microbially produced polyhydroxyalkanoates, and the strength of molded products is reduced. There is no.

  As the heat stabilizer and / or hydrolysis inhibitor in the present invention, any heat stabilizer and / or hydrolysis inhibitor used in biomass resource-derived resins such as polylactic acid can be used. Examples of the heat stabilizer in the present invention include an antioxidant. Examples of the antioxidant include a phenol-based antioxidant, a phosphite-based antioxidant, a sulfur-based antioxidant, a thioether-based antioxidant, Examples include epoxy compounds and hydroxyamine compounds. Examples of the hydrolysis inhibitor include carbodiimide compound hydrolysis inhibitors, isocyanate compounds, oxazoline compounds, epoxy compounds, epoxidized fatty acid alkyl esters, and epoxidized fatty acid glycerin esters.

  Among the above heat stabilizers and / or hydrolysis inhibitors, at least one selected from phenol-based antioxidants, phosphite-based antioxidants, and carbodiimide compound-based hydrolysis inhibitors is preferably used. Moreover, a heat stabilizer and / or a hydrolysis inhibiting agent can use multiple types simultaneously, and can improve an effect. For example, a more preferable effect can be expected by simultaneously using a phenolic antioxidant, a phosphite antioxidant, and a carbodiimide compound hydrolysis inhibitor.

  Examples of the phenolic antioxidant include hindered phenol, polycyclic hindered phenol, monoester type hindered phenol, tetraester type hindered phenol, and diester type hindered phenol. Monoester type hindered phenols include 3- (4′-hydroxy-3′-5′-di-t-butylphenyl) propionic acid-n-octadecyl, pentaerythrityl tetrakis [3- (3,5- Di-t-butyl-4-hydroxyphenyl) propionate], n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, and the like. Examples of the tetraester type hindered phenol include tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane.

  Phosphite antioxidants include tris (2,4-di-t-butylphenyl) phosphite, tris [2-[[2,4,8,10-tetrakis (1,1-dimethylethyl) dibenzo [ d, f] [1,3,2] dioxaphosphepin-6-yl] oxy] ethyl] amine, 3,9-bis (2,6-di-tert-butyl-4-methylphenoxy) -2 , 4,8,10-Tetraoxa-3,9-diphosphaspiro [5.5] undecane, 2,2'-bis (2,6-di-tert-butyl-4-methylphenoxy) -5,5'-spirobi [1 , 3,2-dioxaphosphorinane], 2,2′-bis (2,6-di-tert-butyl-4-methylphenoxy) spiro [4H-1,3,2-dioxaphosphorin-5 ( 6H), 5 ′ (6′H)-[4H-1,3,2] dioxaphospholine], 2,2′-bis (2,6-di-tert-butyl-4-methylphenoxy) spiro [ 1,3,2-dioxaphosphorinane-5,5 ′-[1,3,2] dioxaphosphorinane], 3,9-bis (2,6-di-tert-butyl-4-methylphenyloxy) ) -2,4,8,10-Tetraoxa-3,9- Phosphaspiro [5.5] undecane, 2,2'-bis (2,4-di-tert-butylphenoxy) spiro [1,3,2-dioxaphosphorinane-5,5 '-[1,3,2] di Oxaphosphorinane], and the like.

  Examples of the carbodiimide compound-based hydrolysis inhibitor include carbodiimide-modified isocyanate.

  In the copolymer resin composition of the present invention, the lactic acid copolymer (copolymer A) has a weight average molecular weight (MW) of 20,000 to 1,000,000, preferably 50,000 to 800,000. More preferably, it is 70,000 or more and 800,000 or less. If the weight average molecular weight is less than 20,000, the molded product tends to be brittle, the mechanical strength, particularly impact resistance may be lowered, and may not be used as a general-purpose resin molded product. A lactic acid copolymer having a weight average molecular weight exceeding 1,000,000 is not easily produced.

  The copolymer resin composition of the present invention can be produced from readily available biomass raw materials as in the conventional polylactic acid resin composition by having the above-described configuration, has biodegradability, and is a conventional polylactic acid resin. Heat resistance is higher than that of the composition, the moldability is excellent, and thermal decomposition during heating can be suppressed as compared with conventionally known microorganism-produced polyhydroxyalkanoates for molded articles.

  The copolymer resin composition according to the present invention comprises a 3HV monomer unit represented by the chemical formula [1] and a 3HV monomer unit represented by the chemical formula [2] in the lactic acid copolymer (copolymer A). The molar ratio is preferably in the range of 99: 1 to 75:25, particularly preferably in the range of 96: 4 to 80:20. By setting the molar ratio of the 3HB monomer unit to the 3HV monomer unit in the range of 99: 1 to 75:25, the heat resistance of the copolymer resin composition is improved, and fermentation is performed using a biomass raw material mainly composed of glucose. The 3HB-3HV copolymer, which is the raw material of the copolymer A, can be easily produced by the method, and the merit in raw material procurement and manufacturing process can be utilized.

  When the ratio of 3HB monomer units in the lactic acid copolymer (copolymer A) in the copolymer resin composition is increased in the copolymer resin composition according to the present invention, the heat resistance is improved and the ratio of 3HV monomer units is increased. When the is increased, the impact resistance tends to be improved. By making the molar ratio of the 3HB monomer unit and the 3HV monomer unit in the lactic acid copolymer (copolymer A) within the above range, it has mechanical strength as a general-purpose resin and is more heat resistant than polylactic acid resin. It is possible to provide a copolymer resin composition that is high, has excellent moldability, and can suppress thermal decomposition during heating.

  The copolymer resin composition according to the present invention preferably has a thermal decomposition retention rate (also referred to as a molecular weight retention rate) of 80% or more. Molding that maintains the properties of the copolymer resin composition with almost no thermal decomposition even when heated during kneading, pelletization or molding processing, when the thermal decomposition retention of the copolymer resin composition is 80% or more Can be used for various applications as a general-purpose resin molded product including a housing of an electric / electronic device. Conventionally known 3HB-3HV copolymers have poor thermal decomposition characteristics, and it is usually difficult to achieve a thermal decomposition retention of 80% or more even when a thermal stabilizer is added. It was. Here, the thermal decomposition retention rate of the copolymer resin composition is represented by a reduction rate (%) of the weight average molecular weight (Mw) when the copolymer resin composition is heated at 200 ° C. for 1 minute.

  In the copolymer resin composition according to the present invention, the lactic acid monomer unit represented by the chemical formula [3] is preferably either an L lactic acid monomer unit or a D lactic acid monomer unit. When the lactic acid monomer unit is either the L lactic acid monomer unit or the D lactic acid monomer unit, a copolymer resin composition obtained from a racemic (DL) lactic acid monomer unit that is a mixture of L lactic acid and D lactic acid. In comparison, a copolymer resin composition having excellent heat resistance, particularly thermal decomposition retention, can be obtained. In addition, L lactic acid and D lactic acid should just be an optical isomer of the purity which is not pure and is industrially obtained.

  The copolymer resin composition according to the present invention preferably further contains a crystallization nucleating agent. In particular, the crystallization nucleating agent preferably contains one or more selected from a talc-based nucleating agent, a nucleating agent made of a metal salt-based material having a phenyl group, and a benzoyl compound-based nucleating agent.

  Since the crystallization nucleating agent promotes crystallization of the polylactic acid-based resin composition, the mold temperature at the time of molding can be reduced, the molding time can be shortened, and the heat resistance of the obtained molded product is improved. Among crystallization nucleating agents, talc-based nucleating agents, nucleating agents composed of metal salt-based materials having phenyl groups, and benzoyl compound-based nucleating agents have good compatibility with the copolymer resin composition according to the present invention, so that crystallization is possible. The promoting effect is excellent.

  The copolymer resin composition according to the present invention comprises 4-hydroxybutanoic acid (4HB), 3-hydroxyhexanoic acid (3HHx), 4-hydroxyvaleric acid (4HV) in copolymer A and / or copolymer B. A copolymer resin composition containing monomer units such as 3-hydroxyhexanoic acid (3HHx) and glycolic acid may also be used.

  The molded article according to the present invention is characterized in that the copolymer resin composition containing the crystallization nucleating agent according to the present invention is molded by an injection molding method at a mold temperature of 50 to 90 ° C. In particular, the molded product according to the present invention is excellent as a molded product as a casing for an electric / electronic device.

  If the mold temperature at the time of resin injection molding is about 90 ° C. or less, an inexpensive and simple aqueous medium system can be adopted as a mold temperature control apparatus required for injection molding. (The oil medium method is generally used for temperature control of the mold exceeding 90 ° C.) Further, if the mold temperature is low, the molten resin injected into the mold cavity (cured) The cooling of the previous molded product) can be accelerated, and the molding time, that is, the molding cycle time is shortened. This is because, unlike the polylactic acid, the copolymer resin composition of the present invention is sufficiently crystallized in a temperature range of 50 to 90 ° C., and further, when a crystallization nucleating agent is added, crystallization occurs in the above temperature range. This was achieved because it was found to be particularly fast.

  General-purpose resin molded products can be used for a wide range of applications as long as the above-mentioned deflection temperature under load is 65 ° C. or higher (65 to 100 ° C.), and in particular, as molded products as casings for electrical and electronic equipment. Has sufficient heat resistance. In addition, the resin molded product according to the present invention is a general-purpose resin molded product including a housing for electrical and electronic equipment, and is excellent in raw material availability, productivity and economy, and is environmentally friendly such as biodegradability. It is also preferable from the point that

  The method for producing a copolymer resin composition of the present invention comprises a polyester production step of producing a polyester (3HB-3HV copolymer polyester) containing a 3-hydroxybutyric acid monomer unit and a 3-hydroxyvaleric acid monomer unit by a microbial fermentation method, and the 3HB A lactic acid copolymer production process for producing a lactic acid copolymer (copolymer A) in which lactic acid is added to -3HV copolymer polyester in the range of 50 mol% to 95 mol% as a monomer unit ratio; Polyester copolymer that produces a polyester copolymer (copolymer B) containing a butyric acid monomer unit and a 3-hydroxyvaleric acid monomer unit as a monomer unit ratio of 10 to 25 mol%, preferably 10 to 20 mol%, by microbial fermentation. A coalescence production process, and a predetermined ratio of copolymer A and copolymer B; In example 97: 3 to 70: and a resin mixing step to be mixed with 30 ratio of copolymer resin composition. Furthermore, the method for producing a copolymer resin composition of the present invention preferably includes a nucleating agent addition step of adding a crystallization nucleating agent to the copolymer resin composition. The method for producing a copolymer resin composition of the present invention is preferably an additive addition step in which a heat stabilizer and / or a hydrolysis inhibitor is added to the copolymer resin composition to obtain a copolymer resin composition. Have

  As the heat stabilizer and / or hydrolysis inhibitor, the various types already described can be used, and among them, selected from phenolic antioxidants, phosphite antioxidants, and carbodiimide compound hydrolysis inhibitors. At least one of these is preferably used. Moreover, a heat stabilizer and / or a hydrolysis inhibiting agent can use multiple types simultaneously, and can improve an effect. For example, a more preferable effect can be expected by simultaneously using a phenolic antioxidant, a phosphite antioxidant, and a carbodiimide compound hydrolysis inhibitor.

  In the polyester production process and the polyester copolymer production process in the method for producing a copolymer resin composition of the present invention, a 3HB-3HV copolymer (polyester for producing a lactic acid copolymer, and copolymer B is produced by a microbial fermentation method. Therefore, the molecular weight of the 3HB-3HV copolymer and the ratio of the 3HB monomer unit to the 3HV monomer unit can be easily adjusted by appropriately adjusting the microbial fermentation conditions. In addition, since the microbial fermentation method tends to produce a relatively high molecular weight 3HB-3HV copolymer, it can be hydrolyzed to obtain a 3HB-3HV copolymer having a desired weight average molecular weight. .

  If a polyester having a predetermined weight average molecular weight (3HB-3HV copolymer) can be produced in the polyester production process, the polyester or the polyester is appropriately hydrolyzed in the lactic acid copolymer production process for producing the lactic acid copolymer to obtain a molecular weight. By adding a lactic acid monomer to the prepared polyester to produce a lactic acid copolymer, the lactic acid monomer unit can be blocked and introduced into the polyester. For this reason, the lactic acid copolymer (copolymer A) in the present invention is easy to control the ratio of lactic acid monomer units, and the molecular weight of the lactic acid copolymer, the deflection temperature under load of the copolymer resin composition, the thermal decomposition retention rate. It can be controlled, and is suitable as a raw material resin for molded articles having excellent heat resistance and mechanical strength.

  In the method for producing a copolymer resin composition according to the present invention, the molar ratio of the 3HB monomer unit to the 3HV monomer unit of the polyester (3HB-3HV copolymer) is 99: 1 to 50:50, particularly 95: 5. It is preferable to be in the range of ˜50: 50. By controlling the molar ratio of 3HB monomer units to 3HV monomer units in the polyester within the above range in the polyester production process by microbial fermentation, it has higher heat resistance than polylactic acid resin and suppresses thermal decomposition during heating. A copolymer resin composition that can be used can be provided.

  In the method for producing a copolymer resin composition according to the present invention, the mixing ratio of the copolymer A and the copolymer B is 99: 1 to 60:40, particularly 98: 2 to 65:35, 97: 3. It is preferable to be in the range of ˜70: 30. If the ratio of the copolymer B is too low, the effect of improving the impact resistance cannot be obtained, and if the ratio of the copolymer B is too high, the thermal decomposition retention rate decreases.

  According to the present invention, a biomass resin composition that is biodegradable and has sufficient heat resistance and mechanical strength even if it does not contain a petroleum resin, and a molded product using the same, and biomass The manufacturing method of the resin composition of a system can be provided.

  Hereinafter, embodiments of the present invention will be described in detail.

  The copolymer resin composition as an embodiment according to the present invention will be described.

(Copolymer resin composition)
The copolymer resin composition in the present embodiment is a mixture in which the copolymer A and the copolymer B are mixed at a predetermined ratio.

  The monomer unit of the copolymer A has three components. The monomer unit of the copolymer A includes a 3-hydroxybutyric acid (3HB) monomer unit represented by the chemical formula [1], a 3-hydroxyvaleric acid (3HV) monomer unit represented by the chemical formula [2], and the chemical formula [3]. Lactic acid (LA) monomer units shown, which are copolymerized by ester bonds. Copolymer A in this embodiment is a block copolymer obtained by copolymerizing a lactic acid monomer unit with a copolymer of 3HB monomer units and 3HV monomer units (3HB-3HV copolymer polyester).

  The monomer unit of the copolymer B has two components. The monomer unit of the copolymer B is a 3-hydroxybutyric acid (3HB) monomer unit represented by the chemical formula [1] and a 3-hydroxyvaleric acid (3HV) monomer unit represented by the chemical formula [2]. Copolymerized.

(Polyester (3HB-3HV copolymer polyester))
The 3HB-3HV copolymer polyester (abbreviated simply as polyester) contained in the copolymer A according to the present invention is a copolymer of 3 hydroxybutyric acid (abbreviated as 3HB) and 3hydroxyvaleric acid (abbreviated as 3HV) (abbreviated as P). -3HB-co-3HV), and a copolymer (abbreviated as P-3HB-co-3HV-co-3HHx) in which 3hydroxyhexanoic acid (abbreviated as 3HHx) is further copolymerized with P-3HB-co-3HV. ) And other monomer components may be included. From the viewpoint of productivity and economy, P-3HB-co-3HV is preferably used.

The polyester is also called polyhydroxyalkanoate (abbreviation PHA) and has biodegradability. From the viewpoint of easy availability of raw materials and biodegradability, those produced by microbial fermentation using glucose, propionic acid or the like as a carbon source are preferred. Microbial fermentation method, to a microorganism having polyhydroxyalkanoate synthase gene, may be produced by providing a propionic acid or C ₆ or more even number fatty acids to glucose medium. For example, P-3HB-co-3HV is produced by using a polyhydroxyalkanoate-producing bacterium such as Bacillus genus, Ralstonia genus, Pseudomonas genus, etc., and culturing cells by limiting nitrogen and phosphate in the medium components. It can be produced in two stages: growth and polyester production.

Poly-3hydroxybutyrate (abbreviated as P-3HB) can be produced by Pseudomonas spp., Ralstonia spp., Bacillus spp., Corynebacterium spp. In LB medium, MR medium etc. using glucose as a carbon source, by adjusting it to nitrogen and phosphate auxiliary materials as the addition of propionic acid or _{C 6} or more even number of the fatty acid in the medium components, O started the 3HB-3HV copolymer polyester (P-3HB-co-3HV ) Thus, polyhydroxyalkanoate (PHA), which is a variety of 3HB copolymers, can be produced.

(Copolymer A)
The copolymer A in the present invention is a copolymer further containing a lactic acid monomer unit in the above polyester (3HB-3HV copolymer), and is a kind of polyhydroxyalkanoate (PHA) in a broad sense. In the copolymer A, lactic acid, 3HB, and 3HV may be copolymerized randomly or regularly. The copolymer A in the present invention is preferably a block copolymer obtained by addition polymerization of lactic acid to the polyester (3HB-3HV copolymer) produced by the above-mentioned microbial fermentation method.

  For addition polymerization of lactic acid to polyester (3HB-3HV copolymer), polyester (3HB-3HV copolymer) and lactic acid may be polymerized in an organic solvent using a polymerization initiator such as tin octylate. Adjustment of the content of the lactic acid monomer unit in the obtained lactic acid copolymer and the molecular weight of the lactic acid copolymer can be controlled by the ratio of the raw material polyester and lactic acid, the addition amount of the polymerization initiator, the reaction temperature, the reaction time, and the like. Usually, the desired copolymer A is obtained at a reaction temperature of 100 to 150 ° C. for about 10 to 50 hours. Moreover, in order to adjust the molecular weight of the copolymer A and the molecular weight of the 3HB-3HV copolymer polyester block (3HB-3HV block) in the copolymer A, the PHA obtained by the above microbial fermentation method is desired by hydrolysis. It may be used after the molecular weight of.

  The lactic acid used for the production of the copolymer A in the present invention may be any lactic acid, but L lactic acid, D lactic acid, and L lactic acid and D lactic acid produced by a conventionally known microbial fermentation method. A mixture (racemic, DL) is used. In particular, when a lactic acid copolymer (copolymer A) is prepared using either L lactic acid or D lactic acid as a raw material, thermal decomposition during molding of the obtained copolymer resin composition can be suppressed. preferable. In addition, L lactic acid and D lactic acid are produced by a normal separation technique or synthetic technique, and may not be strictly limited to L lactic acid or D lactic acid.

The weight average molecular weight Mw of the copolymer A used in the present embodiment is controlled by adjusting the molecular weight of the 3HB-3HV block and adjusting the molecular weight of the polylactic acid block. The weight average molecular weight Mw of the copolymer A is 20,000-1,000,000. When the weight average molecular weight Mw is out of the above range, the heat resistance, impact resistance and moldability of the molded product of the resin composition are inferior. In particular, when the weight average molecular weight Mw is less than 20,000, the resin composition tends to be brittle, and moldability and impact resistance are lowered.
(Copolymer B)
Copolymer B in the present invention is a polyester copolymer obtained by copolymerization of 3HB and 3HV. The copolymer B may be the polyester (3HB-3HV copolymer) used in the copolymer A, or may be a polyester copolymer having a different ratio of 3HB and 3HV. The ratio of 3HV in the polyester copolymer (copolymer B) can be controlled by adjusting the ratio of carbon sources such as glucose and propionic acid in the medium components when producing by microbial fermentation. Further, the molecular weight in the polyester copolymer (copolymer B) may be prepared by hydrolyzing a relatively high molecular weight polyester copolymer produced by a microbial fermentation method.

  The weight average molecular weight Mw of the copolymer B used in this embodiment is controlled by adjusting the molecular weight of the hydroxyalkanoate copolymer block. The weight average molecular weight Mw of the copolymer B is 20,000-1,000,000. When the weight average molecular weight Mw is out of the above range, the heat resistance, impact resistance and moldability of the molded product of the resin composition are inferior. In particular, when the weight average molecular weight Mw is less than 20,000, the resin composition tends to be brittle, and moldability and impact resistance are lowered.

(Crystal nucleating agent)
The crystallization nucleating agent used in the copolymer resin composition according to the present invention may be any crystallization nucleating agent used in a thermoplastic resin derived from biomass resources such as polylactic acid. For example, a talc nucleating agent, a nucleating agent made of a metal salt-based material having a phenyl group, a nucleating agent made of a benzoyl compound, or the like is preferably used. Other known crystallization nucleating agents such as lactate, benzoate, silica, and phosphate ester salts may be used.

(Heat stabilizer and hydrolysis inhibitor)
The copolymer resin composition of the present embodiment includes a phenolic antioxidant and a phosphite antioxidant as a heat stabilizer of the resin composition, and a carbodiimide compound hydrolysis inhibitor as a hydrolysis inhibitor, for example, It preferably contains a polycarbodiimide resin (trade name: Carbodilite, manufactured by Nisshinbo Chemical Co., Ltd.). The heat stabilizer and hydrolysis inhibitor to be added may be one selected from the above three additives, but the two heat stabilizers and hydrolysis inhibitors have different functions. It is preferable that each additive is added together. Although the addition amount of a heat stabilizer and a hydrolysis inhibitor changes with kinds, generally 0.1 mass part-about 5 mass parts are preferable with respect to 100 mass parts of copolymer resin compositions, respectively.

(Other additives)
To the copolymer resin composition of the present embodiment, a silicone flame retardant, an organic metal salt flame retardant, an organic phosphorus flame retardant, a metal oxide flame retardant, a metal hydroxide flame retardant, and the like are further added. Is preferred. Thereby, while flame retardance improves and a fire spread can be suppressed, the fluidity | liquidity of a biodegradable resin composition improves, Therefore The more outstanding moldability is securable.

  As said silicone type flame retardant, alkyl siloxane, alkylphenyl siloxane, etc. can be used, for example. More specifically, commercially available products such as X40-9805 (trade name) manufactured by Shin-Etsu Silicone and MB50-315 (trade name) manufactured by Dow Corning Silicone may be used.

  Examples of the organic metal salt flame retardant include organic sulfonic acid metal salts such as potassium trichlorobenzene sulfonate, potassium perfluorobutane sulfonate, potassium diphenyl sulfonate-3-sulfonate, aromatic sulfonic imide metal salts, and styrene. Polystyrene sulfonic acid alkali metal salts in which sulfonic acid metal salts, sulfate metal salts, phosphate metal salts, borate metal salts are bonded to the aromatic ring of aromatic group-containing polymers such as polyphenylene ethers can be used. .

  Examples of the organic phosphorus flame retardant include phosphine, phosphine oxide, biphosphine, phosphonium salt, phosphinate, phosphate ester, phosphite ester, and the like. More specifically, triphenyl phosphate, methyl neopentyl phosphite, pentaerythritol diethyl diphosphite, methyl neopentyl phosphate, phenyl neopentyl phosphate, pentaerythritol diphenyl diphosphate, dicyclopentyl high positive phosphate, Dineopentyl hypophosphite, phenyl pyrocatechol phosphite, ethyl pyrocatechol phosphate, dipyrrocatechol high positive phosphate and the like can be used.

  Examples of the metal oxide flame retardant include magnesium oxide, and examples of the metal hydroxide flame retardant include magnesium hydroxide.

  Further, as the flame retardant aid, an anti-drip agent such as polytetrafluoroethylene can be used.

  A lactic acid-based polyester can be further added as a modifier to the copolymer resin composition of the present embodiment. Thereby, not only the impact resistance is improved, but also the flame retarding effect is improved. As the lactic acid-based polyester as the modifier, a polymer obtained by copolymerizing lactic acid, dicarboxylic acid and diol can be used. Examples of the dicarboxylic acid include succinic acid, adipic acid, sebacic acid, decanedicarboxylic acid, cyclohexanedicarboxylic acid, phthalic acid, terephthalic acid, and isophthalic acid. Examples of the diol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and the like. More specifically, “EXP-PD-150” (trade name) manufactured by Dainippon Ink can be suitably used. Furthermore, as other modifiers, 1,3-butanediol sebacate and the like can be used.

  A filler can be added to the copolymer resin composition of this embodiment. Examples of the filler include talc, mica, montmorillonite, and kaolin. When these fillers become crystal nuclei, crystallization of polylactic acid is promoted, and the impact strength and heat resistance of the molded body are improved. Moreover, the rigidity of the molded body can be increased.

  The copolymer resin composition of the present embodiment includes various additives such as a plasticizer, a compatibilizer, a weather resistance improver, an ultraviolet absorber, a processing aid, an antistatic agent, a colorant, a lubricant, and a release agent. Can also be suitably blended. As the plasticizer, known ones generally used as polymer plasticizers can be used without any particular limitation. For example, polyester plasticizers, glycerin plasticizers, polycarboxylic acid ester plasticizers, polyalkylene glycol plasticizers. And epoxy plasticizers. The compatibilizing agent is not particularly limited as long as it functions as a compatibilizing agent for copolymer A and copolymer B. Examples of the compatibilizer include an inorganic filler, a glycidyl compound, a polymer compound obtained by grafting or copolymerizing an acid anhydride, and an organometallic compound, and one or more of these may be used. These kneadings improve heat resistance, bending strength, impact strength, flame retardancy, etc., and further promote application to molded products such as casings for electronic devices such as laptop computers and mobile phones. The

  In addition, hemp fiber, chitin / chitosan, coconut shell fiber, kenaf, cellulose fiber, silk fiber, short fiber derived from these (length of 10 mm or less), powder derived from these, etc. are added as fillers. be able to. These fillers can improve the mechanical strength, rigidity and heat resistance of the molded body. Moreover, these are natural materials and do not reduce the biodegradability of the molded body. Furthermore, it is preferable to add glass fiber, carbon fiber, glass flake, glass bead, etc. as a filler. Thereby, the rigidity of a molded object can be enlarged. The filler may be subjected to a surface treatment such as coating with polylactic acid or another fatty acid, or may be subjected to a surface treatment with a silane coupling agent or the like.

  Plant fibers include those that are dried and pulverized as they are, and containing lignin, hemicellulose, and other components, those that have been dried and pulverized after alkaline removal of plant fibers, those that have been pulverized from pulp and waste paper, Finely pulverized and microfibrillated can be used. The material for improving the mechanical strength of the molded product is not particularly limited as long as it is not a plant fiber but a bacterial cellulose produced by microorganisms can be used. In addition, the type of raw material plant is not particularly limited. Considering harmony with the environment, such as fast-growing plants such as jute, kenaf, and bamboo, and rice, corn, and sugarcane after collecting edible parts. Therefore, it is desirable to select the blend and blend ratio as appropriate.

  When a mechanical strength reinforcing material such as plant fiber is used, a coupling agent or a compatibilizing agent can be appropriately blended. As the coupling agent, known ones can be used without particular limitation, and examples thereof include a silane coupling agent, an aminosilane coupling agent, and an alkoxysilane coupling agent. Examples of the compatibilizer include inorganic fillers, glycidyl compounds, polymer compounds obtained by grafting or copolymerizing acid anhydrides, and organometallic compounds, and one or more of these may be used.

(Physical property measurement)
-Weight average molecular weight of copolymer A and copolymer B The weight average molecular weight (Mw) of copolymer A and copolymer B in the present invention is preferably 20,000 to 1,000,000, Preferably it is 70,000-800,000. The weight average molecular weight (Mw) is calculated as a standard polystyrene conversion value by Gel Permeation Chromatography (GPC method). The weight average molecular weight (Mw) may be measured for a copolymer resin composition obtained by adding an additive such as a crystallization nucleating agent to the copolymer A. In this case, in the GPC method, the fraction in the low molecular weight region considered to be derived from the additive component may be cut and measured.

-Measurement of molar ratio of monomer units of copolymer A and copolymer B The molar ratio of lactic acid monomer unit, 3HB monomer unit, and 3HV monomer unit in copolymer A and copolymer B in the present invention is , Calculated from proton NMR measurement results.

-Deflection temperature under load It is preferable that the deflection temperature under load of the copolymer resin composition concerning this invention is 65 degreeC or more. The deflection temperature under load is measured by the JIS K 7191-2 (1996) A method, that is, the deflection temperature under a bending stress of 1.80 MPa. Specifically, using a strip test piece having a length of 130 mm, a width of 3.2 mm, and a height of 12.7 mm, the distance between fulcrums is 100 mm, the heating rate is 2 ° C./nin, and the bending stress is 1.80 MPa. The strip test piece is obtained by using a copolymer resin composition pellet, using an electric injection molding machine with a clamping force of 50 tons, a mold temperature of 80 ° C., a cylinder temperature of 180 ° C., an injection speed of 20 mm / s, an injection pressure of 100 MPa, Molding was performed with a cooling time of 30 sec, and annealing was performed until sufficient crystallization progressed.

  It should be noted that the resin composition is not limited to biomass, and can be used even when the heat resistance (deflection temperature under load) is 56 ° C. or higher. However, when used in a casing for electronic / electric equipment, the electronic / electric equipment is transported. It is necessary to guarantee heat resistance (deflection temperature under load) of 60, preferably 65 ° C., from the temperature environment of the time. For this reason, a resin composition having a heat resistance of 65 ° C. or higher is often selected for electronic / electrical devices with a margin. The heat resistance test method for a resin composition is generally evaluated based on a JIS-compliant load deflection temperature assuming that a mechanical stress is applied to the casing.

-Thermal decomposition retention ratio The thermal decomposition retention ratio (also referred to as molecular weight retention ratio) (%) of the copolymer resin composition according to the present invention is preferably 80% or more. The thermal decomposition retention is expressed as a reduction rate (%) of the weight average molecular weight (Mw) after heating the copolymer resin composition at 200 ° C. for 10 minutes as shown in the following formula:
[Pyrolysis retention] = {[Mw before heating]-[Mw after heating]} / [Mw before heating] × 100
Calculate as The weight average molecular weight (Mw) may be measured by the above GPC method. As with the weight average molecular weight measurement, in the case of a copolymer resin composition obtained by adding an additive such as a crystallization nucleating agent to a lactic acid copolymer, the weight average molecular weight (Mw) is derived from the additive component in the GPC method. The fraction of the low molecular weight region considered to be cut is calculated.

  The test conditions for the thermal decomposition retention rate are set from the molding conditions for the resin composition. In the case of the copolymer resin composition according to the present invention, for example, because the cylinder temperature at the time of molding is 180 ° C., the test condition for the thermal decomposition retention rate is relatively 200 ° C. with a margin of temperature variation added. Strict conditions. Moreover, since the time which a resin composition retains in the heating cylinder of an injection molding machine at the time of shaping | molding shall be about 5 to 10 minutes, for example, the heating time is defined as 10 minutes. The thermal decomposition retention rate is calculated from the thermal decomposition retention rate of the resin composition before and after the test conditions. In general, it is known that a resin composition has a molecular weight that decreases under heating conditions, and mechanical strength such as impact strength decreases. Although there is a proportional relationship between the molecular weight and the impact strength of the resin composition, in order to keep the impact strength before decomposition as 100 and hold 50% or more, the thermal decomposition retention rate should be 80% or more. preferable.

-Charpy impact strength The Charpy impact strength of the copolymer resin composition according to the present invention is preferably 6 kJ / m ² or more. The Charpy impact strength is measured by the method of JIS K 7111-1. Specifically, using a strip test piece having a length of 80 mm, a width of 4 mm, and a height of 10 mm, the measurement is performed with a support stand span of 62 mm. The strip test piece is obtained by using a copolymer resin composition pellet, using an electric injection molding machine with a clamping force of 50 tons, a mold temperature of 80 ° C., a cylinder temperature of 180 ° C., an injection speed of 20 mm / s, an injection pressure of 100 MPa, Molding was performed with a cooling time of 30 sec, and annealing was performed until sufficient crystallization progressed.

Example 1
<Preparation of copolymer B1>
Bacillus was cultured for 16 hours in a medium containing 5.0 g / l peptone, 5.0 g / l yeast extract, and 5.0 g / l meat extract. Propionic acid was added to the obtained culture broth in a minimal medium (containing glucose) with a nitrogen source restricted, and cultured at 45 ° C. for 48 hours to obtain a cultured microbial cell containing polyester. The obtained cultured cells were lyophilized and chloroform was added to extract the cells. Insoluble matter was filtered off, methanol was added to the filtrate to reprecipitate the bacterial cell extract, which was filtered, and the purified bacterial cell product was designated as copolymer B1. By analyzing the copolymer B1 by NMR, the content ratio (molar ratio) of the 3-hydroxybutyric acid monomer unit (3HB) to the 3-hydroxyvaleric acid monomer unit (3HV) was about 83:17. Moreover, the weight average molecular weight (Mw) by GPC method of copolymer B1 was 350,000 in standard polystyrene conversion value.

<Preparation of copolymer A1>
A part of this cell product (copolymer B1) was treated with alkaline warm water to be hydrolyzed to lower the molecular weight and dried to obtain polyester 1. Next, 0.05 g of polyester 1 was dissolved in 1 liter of anhydrous toluene, 0.95 g of L lactic acid and 0.1 g of tin octylate were added, and the mixture was stirred in a nitrogen atmosphere at 130 ° C. for 24 hours, and then further 130 The mixture was allowed to stand at 24 ° C. for 24 hours. Then, it hold | maintained in a vacuum atmosphere for 1 hour, it returned to room temperature, the obtained product was dissolved in chloroform, methanol and hexane were added, and the deposit was filtered and collect | recovered. The precipitate was purified by repeating dissolution, precipitation, and filtration, and finally dried under vacuum to obtain a purified product. The obtained purified product was subjected to NMR analysis to confirm that it was a lactic acid copolymer (Co-PLA), and this was designated as copolymer A1. The content ratio (molar ratio) of L-lactic acid monomer unit (LLA), 3-hydroxybutyric acid monomer unit (3HB), and 3-hydroxyvaleric acid monomer unit (3HV) in copolymer A1 was 95: 4: 1. Moreover, the weight average molecular weight (Mw) by GPC method of copolymer A1 was 171,000 in standard polystyrene conversion value.

  The compositions of copolymer A1 and copolymer B1 are shown in Tables 1 and 2, respectively. The copolymerization ratio in Table 1 is the molar ratio of 3HB, 3HV, and LA in the copolymer A1, and the copolymerization ratio in Table 2 is the molar ratio of 3HB, 3HV in the copolymer B1. ing.

<Preparation of copolymer resin composition 1>
Next, the copolymer A1 and the copolymer B1 are melt-kneaded at a temperature ratio of 180 ° C. with a biaxial kneading extruder at a mass ratio of 90:10 to produce a molding pellet having a size of about 3 mm. Copolymer resin composition 1 was obtained.

<Measurement of deflection temperature under load of copolymer resin composition 1>
About the copolymer resin composition 1, the produced pellet was dried at 50 ° C. for 12 hours using a shelf-type hot air dryer, and then the mold was molded using an electric injection molding machine having a clamping force of 50 tons. Injection molding was performed at a temperature of 80 ° C., a cylinder temperature of 180 ° C., an injection speed of 20 mm / s, an injection pressure of 100 MPa, and a cooling time of 30 sec. The molded article was subjected to primary annealing at 80 ° C. for 15 minutes and secondary annealing at 60 ° C. for 12 hours to obtain a strip test piece for a load deflection temperature test. The size of the produced strip test piece is 130 mm in length, 3.2 mm in width, and 12.7 mm in height. The test of deflection temperature under load was performed according to JIS K 7191-2 (1996). The distance between the fulcrums was 100 mm, the heating rate was 2 ° C./min, and the bending stress was 1.80 MPa. The deflection temperature under load of the copolymer resin composition 1 was 80 ° C.

<Measurement of thermal decomposition retention rate of copolymer resin composition 1>
1 g of the copolymer resin composition 1 was placed on a hot plate and heated at 200 ° C. for 10 minutes. About the resin composition 1 before a heating and after a heating, the weight average molecular weight (Mw) by GPC method was measured, respectively, and the thermal decomposition retention (%) was computed using the following formula.
Thermal decomposition retention rate = {(Mw before heating) − (Mw after heating)} / (Mw before heating) × 100
The thermal decomposition retention rate of the copolymer resin composition 1 was 90%.

<Charpy impact strength measurement of copolymer resin composition 1>
About the copolymer resin composition 1, the produced pellet was dried at 50 ° C. for 12 hours using a shelf-type hot air dryer, and then the mold was molded using an electric injection molding machine having a clamping force of 50 tons. Injection molding was performed at a temperature of 80 ° C., a cylinder temperature of 180 ° C., an injection speed of 20 mm / s, an injection pressure of 100 MPa, and a cooling time of 30 sec. The molded product was subjected to primary annealing at 80 ° C. for 15 minutes and secondary annealing at 60 ° C. for 12 hours to obtain strip test pieces for Charpy impact test. The size of the produced strip test piece is 80 mm in length, 4 mm in width, and 10 mm in height. The Charpy impact strength test was performed according to JIS K 7111-1. The Charpy impact strength of the copolymer resin composition 1 was 6.7 kJ / m ² .
The composition and properties of the above copolymer resin composition 1 are summarized and shown in the column of Example 1 in Table 3.

(Example 2)
<Preparation of copolymer A2>
In Example 1 <Production of copolymer B1>, except that the culture conditions of the Bacillus culture medium and the hydrolysis conditions of the obtained bacterial product were changed when copolymer B1 was produced. In the same manner as in Example 1, a copolymer B1 ′ having a content ratio (molar ratio) of the 3-hydroxybutyric acid monomer unit (3HB) and the 3-hydroxyvaleric acid monomer unit (3HV) of 97: 3 was produced.

  Next, copolymer B1 in <Production of copolymer A1> in Example 1 is hydrolyzed to replace polyester 1 and, instead, copolymer B1 ′ is hydrolyzed to produce polyester 2, and anhydrous 0.05 g of polyester 1 was dissolved in 1 liter of toluene, and 0.05 g of polyester 2 was dissolved in 1 liter of anhydrous toluene instead of adding 0.95 g of L lactic acid and 0.1 g of tin octylate. A purified product was obtained in the same manner as in Example 1 except that 0.5 g of lactic acid and 0.1 g of tin octylate were added and added. The obtained purified product was subjected to NMR analysis to confirm that it was a lactic acid copolymer (Co-PLA), and this was designated as copolymer A2. The content ratio (molar ratio) of the L-lactic acid monomer unit (LLA), the 3-hydroxybutyric acid monomer unit (3HB), and the 3-hydroxyvaleric acid monomer unit (3HV) in the copolymer A2 was 54: 44: 2. Moreover, the weight average molecular weight (Mw) by GPC method of copolymer A3 was 73,000 in standard polystyrene conversion value. The composition and weight average molecular weight of the copolymer A2 are shown in Table 1.

<Preparation of copolymer resin composition 2>
Next, the copolymer A2 and the copolymer B1 produced in Example 1 were melt-kneaded at a temperature ratio of 180 ° C. with a biaxial kneading extruder at a mass ratio of 90:10 to form a size of about 3 mm. Pellets were prepared, and a copolymer resin composition 2 was obtained.

<Measurement of deflection temperature under load, thermal decomposition retention rate, Charpy impact strength of copolymer resin composition 2>
In the same manner as in Example 1, the deflection temperature under load, the thermal decomposition retention rate, and the Charpy impact strength of the copolymer resin composition 2 were measured, and the measurement results together with the composition of the copolymer resin composition 2 and the like. Similarly, it was shown in the column of Example 2 in Table 3.

(Example 3)
<Preparation of copolymer B2>
In <Production of Copolymer B1> in Example 1, the culture conditions of the Bacillus culture medium were adjusted, and the content ratio (molar ratio) of the 3-hydroxybutyric acid monomer unit (3HB) and the 3-hydroxyvaleric acid monomer unit (3HV) ) Produced a copolymer B2 of 87.6: 12.4. The weight average molecular weight (Mw) by GPC method of copolymer B2 was 780,000 in terms of standard polystyrene. The composition and weight average molecular weight of the copolymer B2 are shown in Table 2.

<Preparation of copolymer resin composition 3>
Next, the copolymer A1 and the copolymer B2 prepared in Example 1 were melt-kneaded at a temperature ratio of 180 ° C. with a biaxial kneading extruder at a mass ratio of 90:10 to form a size of about 3 mm. The pellet for this was produced and it was set as the copolymer resin composition 3.

<Measurement of deflection temperature under load, thermal decomposition retention rate, Charpy impact strength of copolymer resin composition 3>
In the same manner as in Example 1, the deflection temperature under load, the thermal decomposition retention rate, and the Charpy impact strength of the copolymer resin composition 3 were measured, and the measurement results together with the composition of the copolymer resin composition 3 and the like. Similarly, it was shown in the column of Example 3 in Table 3.

Example 4
<Preparation of copolymer resin composition 4>
The copolymer A2 produced in Example 2 and the copolymer B2 produced in Example 3 were melt-kneaded at a temperature ratio of 180 ° C. with a biaxial kneading extruder at a mass ratio of 90:10. A molding pellet having a size of about 3 mm was prepared as a copolymer resin composition 4.

<Measurement of deflection temperature under load, thermal decomposition retention rate, Charpy impact strength of copolymer resin composition 4>
In the same manner as in Example 1, the deflection temperature under load, the thermal decomposition retention rate, and the Charpy impact strength of the copolymer resin composition 4 were measured, and the measurement results together with the composition of the copolymer resin composition 4 and the like. Similarly, it was shown in the column of Example 4 in Table 3.

(Example 5)
<Preparation of copolymer resin composition 5>
The copolymer A1 and the copolymer B1 prepared in Example 1 are melt-kneaded at a temperature ratio of 180 ° C. with a twin-screw kneading extruder at a mass ratio of 99: 1, and a molding pellet having a size of about 3 mm. Was made to be a copolymer resin composition 5.

<Measurement of deflection temperature under load, thermal decomposition retention rate, Charpy impact strength of copolymer resin composition 5>
In the same manner as in Example 1, the deflection temperature under load, the thermal decomposition retention rate, and the Charpy impact strength of the tree copolymer fat composition 5 were measured, and the measurement results together with the composition of the copolymer resin composition 5, etc. The results are shown in the column of Example 5 in Table 3.

(Example 6)
<Preparation of copolymer resin composition 6>
The copolymer A1 and the copolymer B1 prepared in Example 1 were melt-kneaded at a temperature ratio of 180 ° C. with a twin-screw kneading extruder at a mass ratio of 70:30, and a molding pellet having a size of about 3 mm. Was made to be a copolymer resin composition 6.

<Measurement of deflection temperature under load, thermal decomposition retention rate, Charpy impact strength of copolymer resin composition 6>
In the same manner as in Example 1, the deflection temperature under load, thermal decomposition retention rate, and Charpy impact strength of the copolymer resin composition 6 were measured, and the measurement results together with the composition of the copolymer resin composition 6 and the like. Similarly, it was shown in the column of Example 6 in Table 3.

(Example 7)
<Preparation of copolymer resin composition 7>
In <Preparation of Copolymer Resin Composition 1> in Example 1, 100 parts by mass of the prepared resin composition 1 was used as a crystallization nucleating agent as a crystallization nucleating agent 1 (talc nucleating agent; Nippon Talc Co., Ltd.). Company SG-2000 Nissan), crystallization nucleating agent 2 (nuclear agent made of metal salt-based material with phenyl group; PPA-Zn made by Nissan Chemical Co., Ltd.), crystallization nucleating agent 3 (benzoyl compound nucleating agent) Respectively, 0.5 parts by mass of T-1287N manufactured by ADEKA Corporation was added and kneaded to obtain copolymer resin composition 7.

<Measurement of deflection temperature under load, thermal decomposition retention rate, Charpy impact strength of copolymer resin composition 7>
In the same manner as in Example 1, the deflection temperature under load, the thermal decomposition retention rate, and the Charpy impact strength of the copolymer resin composition 7 were measured, and the measurement results together with the composition of the copolymer resin composition 7 and the like. Similarly, it was shown in the column of Example 7 in Table 3.

(Comparative Example 1)
<Preparation of copolymer resin composition 8, deflection temperature under load, and Charpy impact strength measurement>
Commercially available poly L lactic acid (PLA; Lacia H-100 manufactured by Mitsui Chemicals, Inc.) was used as copolymer resin composition 8. In the same manner as in Example 1, the deflection temperature under load and the Charpy impact strength of the copolymer resin composition 8 were measured, and the measurement results are shown in the column of Comparative Example 1 in Table 4.

(Comparative Example 2)
<Preparation of copolymer resin composition 9 and deflection temperature under load and Charpy impact strength measurement>
In Comparative Example 1, with respect to 100 parts by mass of the prepared copolymer resin composition 8 (commercially available polylactic acid), as a crystallization nucleating agent, crystallization nucleating agent 1 (talc nucleating agent; SG manufactured by Nippon Talc Co., Ltd.) -2000), crystallization nucleating agent 2 (nuclear agent made of metal salt-based material having a phenyl group; PPA-Zn made by Nissan Chemical Co., Ltd.), crystallization nucleating agent 3 (benzoyl compound nucleating agent; made by ADEKA Corporation) Each of T-1287N) was added in an amount of 0.5 parts by mass and kneaded to obtain a copolymer resin composition 9. In the same manner as in Example 1, the deflection temperature under load and the Charpy impact strength of the copolymer resin composition 9 were measured, and the measurement results together with the composition of the copolymer resin composition 9 and the measurement results were shown in Comparative Example 2 in Table 4. It is shown in the column.

(Comparative Example 3)
<Preparation of copolymer resin composition 10 and deflection temperature under load, thermal decomposition retention, and Charpy impact strength measurement>
Copolymer A1 produced in Example 1 was designated as copolymer resin composition 10. In the same manner as in Example 1, the deflection temperature under load and the Charpy impact strength of the copolymer resin composition 10 were measured, and the measurement results are shown in the column of Comparative Example 3 in Table 4.

(Comparative Example 4)
<Preparation of copolymer resin composition 11 and deflection temperature under load, thermal decomposition retention, and Charpy impact strength measurement>
Copolymer B1 produced in Example 1 was used as copolymer resin composition 11. In the same manner as in Example 1, the deflection temperature under load, thermal decomposition retention rate, and Charpy impact strength of the copolymer resin composition 11 were measured, and the measurement results are shown in the column of Comparative Example 4 in Table 4.

(Comparative Example 5)
<Preparation of copolymer A12>
In <Production of Copolymer B1> in Example 1, the culture conditions of the Bacillus culture medium were adjusted, and the content ratio (molar ratio) of the 3-hydroxybutyric acid monomer unit (3HB) and the 3-hydroxyvaleric acid monomer unit (3HV) ) Produced a 92: 8 polyester. The weight average molecular weight (MW) of this polyester by GPC method was 1,300,000 in terms of standard polystyrene. Polyester 12 was produced by hydrolyzing this polyester with alkaline warm water to reduce the molecular weight.

  Next, in <Preparation of Copolymer A1> in Example 1, 0.05 g of polyester 1 was dissolved in 1 liter of anhydrous toluene, and 0.95 g of L lactic acid and 0.1 g of tin octylate were added. A purified product was obtained in the same manner as in Example 1 except that 0.7 g of polyester 12, 0.3 g of L lactic acid and 0.1 g of tin octylate were added to 1 liter of anhydrous toluene. The obtained purified product was analyzed by NMR to confirm that it was a lactic acid copolymer (Co-PLA), and this was designated as copolymer A12. The content ratio (molar ratio) of the L-lactic acid monomer unit (LLA), the 3-hydroxybutyric acid monomer unit (3HB), and the 3-hydroxyvaleric acid monomer unit (3HV) in the copolymer A12 was 35: 60: 5. Moreover, the weight average molecular weight (Mw) by GPC method of copolymer A12 was 280,000 in standard polystyrene conversion value. The composition and weight average molecular weight of the copolymer A12 are shown in Table 1.

<Preparation of copolymer resin composition 12>
The copolymer A12 and the copolymer B1 prepared in Example 1 were melt-kneaded at a ratio of 90:10 at a temperature of 180 ° C. with a twin-screw kneading extruder to form molding pellets having a size of about 3 mm. A copolymer resin composition 12 was produced.

<Measurement of deflection temperature under load, thermal decomposition retention rate, and Charpy impact strength of copolymer resin composition 12>
In the same manner as in Example 1, the deflection temperature under load, the thermal decomposition retention rate, and the Charpy impact strength of the copolymer resin composition 12 were measured, and the measurement results together with the composition of the copolymer resin composition 12 and the like. Similarly, it was shown in the column of Comparative Example 5 in Table 4.

(Comparative Example 6)
<Preparation of copolymer B13>
In <Production of Polyester 1> in Example 1, the culture conditions of the Bacillus culture medium were adjusted, and the content ratio (molar ratio) of the 3-hydroxybutyric acid monomer unit (3HB) and the 3-hydroxyvaleric acid monomer unit (3HV) was , 93: 7 copolymer B13 was produced. The weight average molecular weight (Mw) of this polyester by GPC method was 1,300,000 in terms of standard polystyrene. The composition and weight average molecular weight of the copolymer B13 are shown in Table 2.

<Preparation of copolymer resin composition 13>
Next, the copolymer A1 produced in Example 1 and the copolymer B13 are melt-kneaded at a temperature of 180 ° C. in a ratio of 90:10 at a temperature of 180 ° C., and the molding is about 3 mm in size. A pellet was prepared as copolymer resin composition 13.
<Measurement of deflection temperature under load, thermal decomposition retention rate, and Charpy impact strength of copolymer resin composition 13>
In the same manner as in Example 1, the deflection temperature under load, the thermal decomposition retention rate, and the Charpy impact strength of the copolymer resin composition 13 were measured, and the measurement results together with the composition of the copolymer resin composition 13 and the like. Similarly, it was shown in the column of Comparative Example 6 in Table 4.

(Comparative Example 7)
<Preparation of copolymer resin composition 14>
The copolymer A1 and the copolymer B1 prepared in Example 1 were melt-kneaded at a temperature of 180 ° C. with a twin-screw kneading extruder at a ratio of 50:50 to produce a molding pellet having a size of about 3 mm. Copolymer resin composition 14 was obtained.

<Measurement of deflection temperature under load, thermal decomposition retention rate, and Charpy impact strength of copolymer resin composition 14>
In the same manner as in Example 1, the deflection temperature under load, the thermal decomposition retention rate, and the Charpy impact strength of the copolymer resin composition 14 were measured, and the measurement results were compared with those of Comparative Example 1 together with the composition of the copolymer resin composition 14 and the like. Similarly, it was shown in the column of Comparative Example 7 in Table 4.

(Evaluation of copolymer resin compositions in Examples and Comparative Examples)
The compositions, properties, and the like of the copolymer resin compositions in Examples 1 to 7 and Comparative Examples 1 to 7 are shown in Table 3 and Table 4, respectively. The judgment results in Table 3 and Table 4 are those that satisfy all three criteria for the deflection temperature under load, thermal decomposition retention rate, and Charpy impact strength, and those that do not satisfy any criteria. X. The criteria for determination are a deflection temperature under load of 65 ° C. or higher, a thermal decomposition retention of 80% or higher, and a Charpy impact strength of 6 kJ / m ² or higher. N. d. Represents unmeasured.

  The deflection temperatures under load of the resin compositions 1 to 7 in Examples 1 to 7 are 78 to 85 ° C. and 65 ° C. or higher, and the mechanical strength can be maintained in a high-temperature usage environment that is normally assumed. It is a preferable resin composition that can be used in many applications as a general-purpose resin molded product such as a casing of an electronic device.

  The thermal decomposition retention rates of Examples 1 to 7 are 81% or higher, which is higher than 80%, and have heat resistance and hardly deteriorate even when heated in a molding process such as injection molding. As a general-purpose resin molded product such as a body, it can be used for many purposes.

The Charpy impact strength of Examples 1 to 7 is 6 kJ / m ² or more, and can be used for many applications as a general-purpose resin molded product such as a casing of an electric / electronic device.

  On the other hand, the resin compositions 8 and 9 in Comparative Examples 1 and 2 do not include the 3HB monomer unit and the 3HV monomer unit, and the deflection temperature under load is as low as 56 ° C. When the deflection temperature under load of the resin composition is 65 ° C. or lower, the use as a molded product is limited, and in particular, the use is restricted for use as a casing of an electric / electronic device or a food packaging body that requires a certain degree of heat resistance. To be done more.

The resin composition 10 in Comparative Example 3 has a low Charpy impact strength of ² kJ / m ^2, and the impact resistance performance is low only with the copolymer A. There are many cases where the use is restricted such as a place not touching or a place where strength is not required.

  The resin composition 11 in Comparative Example 4 does not contain an LA unit, has a low thermal decomposition retention rate of 30%, and is likely to cause a decrease in molecular weight by heating in a molding process such as kneading, pelletizing, or molding, There is a risk of deterioration of physical properties of the molded product.

  The resin composition 12 in Comparative Example 5 has a low content of LA monomer units in the copolymer A as low as 35%, a thermal decomposition retention as low as 40%, such as during kneading, pelletizing, molding, etc. The heating in the molding process tends to cause a decrease in molecular weight, and the physical properties of the molded product may be greatly deteriorated.

The resin composition 13 in Comparative Example 6 has a low 3HV unit fraction of 7% in the copolymer B, has a Charpy impact strength as low as 1.6 kJ / m ² , a casing of an electric / electronic device, etc. In general-purpose resin molded product applications, use is often restricted to places where human hands do not touch or places where strength is not required.

  In the resin composition 14 in Comparative Example 7, the mixing ratio of the copolymer A and the copolymer B is 50:50, the deflection temperature under load is as low as 63 ° C., and the thermal decomposition retention is as low as 68%. .

  The copolymer resin composition of the present invention can be used as various general-purpose resin molded products. In particular, it can be suitably used for resin parts such as housings used in image output devices such as copiers and printers and electrical / electronic devices such as home appliances. There are various usage and storage environments for electrical and electronic equipment, automobile parts, etc., but devices used in home and office environments generally guarantee a use and storage environment of about 60 ° C. The molded article made of the copolymer resin composition of the present invention has a deflection temperature under load of 60 ° C. or higher, preferably 65 ° C. or higher, and is deformed even in an environment where it is incorporated in an electric / electronic device or automobile part. Can be used without

  In addition, the copolymer resin composition of the present invention is an excellent product from the viewpoint of environmental problems and resource problems because the raw material is obtained from a biomass material and has biodegradability.

JP 2006-335909 A JP 2007-056247 A JP 2007-231034 A Japanese Patent Laying-Open No. 2005-023260 Japanese Patent Laid-Open No. 2007-072232 JP 2006-274182 A Japanese Patent No. 3609543 Japanese Patent No. 3599533 International Publication No. 02/006400 Pamphlet

Claims (8)

Lactic acid co-polymer containing each monomer unit represented by the following chemical formulas [1], [2] and [3], wherein the content of the monomer unit represented by the chemical formula [3] is 50 to 97 mol% And a polyester copolymer containing monomer units represented by the chemical formulas [1] and [2] and having a monomer unit content represented by the chemical formula [2] of 10 to 25 mol%. seen including, mass mixing ratio of the polyester copolymer and the lactic acid copolymer is 99: 1 to 60: a copolymer resin composition, which is a range of 40.

The copolymer resin composition according to claim 1 , wherein the monomer unit represented by the chemical formula [3] is either an L lactic acid monomer unit or a D lactic acid monomer unit. The copolymer resin composition according to claim 1 or 2 , further comprising a crystallization nucleating agent. The crystallization nucleating agent is talc-based nucleating agent, according to claim 3, characterized in that it comprises at least one selected from nucleating agents, and benzoyl compound-type nucleating agent comprising a metal salt-type material having a phenyl group A copolymer resin composition. A molded article, wherein the copolymer resin composition according to any one of claims 1 to 4 is molded with an injection mold having a mold temperature of 50 ° C or higher and 90 ° C or lower. A polyester production process for producing a polyester comprising a 3-hydroxybutyric acid monomer unit and a 3-hydroxyvaleric acid monomer unit by a microbial fermentation method;
A lactic acid copolymer production process for producing a lactic acid copolymer by adding lactic acid to the polyester in a range of 50 to 97 mol% as a monomer unit ratio;
A polyester copolymer production step of producing a polyester copolymer comprising a 3-hydroxybutyric acid monomer unit and 10 to 25 mol% of a 3-hydroxyvaleric acid monomer unit by a microbial fermentation method;
A copolymer mixing step of mixing the lactic acid copolymer and the polyester copolymer at a mass mixing ratio of 99: 1 to 60:40;
A process for producing a copolymer resin composition, comprising: The method for producing a copolymer resin composition according to claim 6 , wherein a crystallization nucleating agent is further mixed in the copolymer mixing step. The crystallization nucleating agent, talc-based nucleating agent, according to claim 7, characterized in that it comprises a nucleating agent composed of a metal salt-type material having a phenyl group and that at least one selected from a benzoyl compound-type nucleating agent A method for producing a copolymer resin composition.