JP2012211243A - Copolymer resin composition, resin molding, and method of manufacturing copolymer resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biomass-based copolymer resin composition which can be used for a housing or the like of electronic equipment, and is excellent in impact resistance and heat resistance.SOLUTION: The copolymer resin composition includes: a polyester copolymer which includes all monomer units that are hydroxycarboxylic acids of specific three kinds, and in which the content ratio of the monomer unit shown by chemical formula (3) is at least 50 mole% and at most 95 mole%; and an olefinic resin or a styrenic resin.

Description

  The present invention relates to a copolymer resin composition, a resin 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 of the movements is to replace plastic raw materials made from petroleum with biomass materials.

  Many resin parts are used in 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. These plastic parts are mostly made from plastics made from petroleum, but they are derived from petroleum due to problems such as carbon dioxide emission reduction, oil resource depletion, and waste disposal (non-biodegradable plastics). Development of technology for converting resin to biomass resource-derived resin 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 resins.

  Biodegradable resins derived from biomass resources are produced by chemical polymerization using lactic acid (abbreviated as LA) produced by fermenting sugars obtained from sugarcane, corn, sweet potatoes, etc. as raw materials. Polylactic acid (abbreviated as PLA), esterified starch mainly composed of esterified starch, and polyhydroxyalkanoate (PHA), which is a microorganism-produced polyester resin produced by microorganisms in the body And 1,3-propanediol obtained by fermentation, and polytrimethylene terephthalate (abbreviated as PTT) using petroleum-derived terephthalic acid as a raw material are known. Yes. 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. In the future, the production of succinic acid, which is one of the main raw materials, from plant-derived raw materials is being 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 as a result, the thermal deformation temperature is around 55 ° C., which is not suitable for applications requiring heat resistance (mechanical strength at relatively high temperatures). was there. 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 that requires strength, 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-based resin, which can include only about 50% of the biomass resource-derived resin at most. Environmental impact reduction effects such as carbon emission reduction and oil consumption reduction will be halved.

  As another measure for improving the physical properties of polylactic acid, a method for improving the heat resistance by promoting the crystallization of polylactic acid by utilizing 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 provide a mold for annealing in order to prevent deformation of the molded product due to crystallization due to annealing, and the cost And there was a problem with productivity.

  With respect to the method of adding a crystallization nucleating agent, various crystallization nucleating agents that improve the crystallinity and the crystallization speed are being developed. However, even if a crystallization nucleating agent is added at present, crystallization time of about 2 minutes is required at the time of molding, and it has not reached the point where it can be molded in the same molding cycle time as that of petroleum-based general-purpose resins. There is a problem with productivity.

  Moreover, since polylactic acid crystallizes at a temperature of about 100 to 110 ° C., it is necessary to adjust the temperature of the mold at 100 ° C. or more during molding, and an inexpensive mold temperature controller using a water-cooled mold is used. There was a problem that it could not be used and the molding cost increased. 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 of about 1.80 MPa) is around 55 ° C., and the heat resistance is high. Inadequate remains a challenge.

  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 conventionally known heat stabilizers, antioxidants, hydrolysis inhibitors and the like are added.

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

  In Cited Document 1 and Cited Document 2, a method for improving the deflection temperature under load and impact resistance of a resin by blending about half of a resin made from petroleum resources such as polycarbonate resin with polylactic acid resin is proposed. . For example, in the 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 There has been proposed an electronic device member characterized in that Also, in Cited Document 2, the acrylic resin unit or the styrene resin unit is 0% with respect to 95 to 5% by weight of the polylactic acid resin, 5 to 95% by weight of the aromatic polycarbonate resin, and 100 parts by weight of these resins in total. A resin composition obtained by blending 0.1 to 50 parts by weight of a flame retardant with a polymer compound obtained by graft polymerization of 1 to 50 parts by weight has been proposed.

  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, jute fiber is shown.

  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. Yes. 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 preferred 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.). 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 a resin with a high environmental impact, such as polycarbonate resin, is blended with polylactic acid resin in half, the resin product from the viewpoint of global environmental measures, even if heat resistance and mechanical strength are improved. The effect of replacing the biomass material with less than half will be less than half. Further, polycarbonate resin is a kind of engineering plastic, and becomes a relatively expensive resin composition in terms of cost.

  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 (hydroxybutyrate-hydroxyvalerate copolymer) can be produced by microbial fermentation from a medium using glucose as a substrate, and is an alternative to polylactic acid resin. Alternatively, it is expected as a complementary resin such as 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 case of the biodegradable polyester resin composition described in Patent Document 5, in the molding of the biodegradable polyester resin composition specifically disclosed, the crystallization temperature is as high as 110 ° C. (see Patent Document 5). 4), it is difficult to adjust the temperature of the mold to about 90 ° C. or less which is 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 hydroxybutyrate-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 that has not been achieved with polylactic acid, has a heat resistance exceeding 60 ° C. (high temperature strength), has excellent moldability, and has 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. Conventional 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 likely to be 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. In addition to the characteristics of individual biomass-derived polyester resins, it is considered that there is a problem of matching between each biomass-derived polyester resin and petroleum resin.

  The object of the present invention is based on the above-mentioned problems, and is based on the biomass-based copolymer resin composition excellent in heat resistance and impact resistance, a resin molded product using this copolymer resin composition, and a copolymer resin composition. It is to provide a manufacturing method.

  The copolymer resin composition of the present invention includes a polyester copolymer containing all monomer units represented by the following chemical formulas (1), (2), and (3), and an olefin resin or a styrene resin. Yes.

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、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。）のである。ポリエステル共重合体中における３ＨＢ、３ＨＶ、ＬＡの３種のモノマーユニットは、ランダムに配列されていてもよいし、規則性を有して配列されていてもよいが、３ＨＢと３ＨＶの共重合ポリエステルブロックにＬＡ重合体ブロックが付加した形態の乳酸共重合体（ブロック共重合体）が好ましく使用できる。

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; 3HV may be abbreviated as a bond) are combined. The monomer unit represented by (3) is lactic acid (2-hydroxypropionic acid; sometimes abbreviated as LA). The 3HB, 3HV, LA three types of monomer units in the polyester copolymer may be arranged at random or may be arranged with regularity, but 3HB and 3HV copolymer polyester. A lactic acid copolymer (block copolymer) in which an LA polymer block is added to the block can be preferably used.

  In the polyester copolymer of the present invention, the content of the lactic acid monomer unit represented by the chemical formula (3) is preferably 50 mol% or more and 95 mol% or less. When the content of the lactic acid monomer unit in the polyester copolymer is 50 mol% or more, the thermal decomposition retention rate of the polyester copolymer is high, and thermal decomposition is performed by heat treatment during kneading or molding as the resin composition. It is difficult to cause or decrease in molecular weight. Moreover, by making the content rate of a lactic acid monomer unit 95 mol% or less, the property of a polylactic acid resin can be weakened and the heat resistance (high temperature strength) at the time of setting it as a molded article can be improved. The polyester copolymer in the present invention may contain other hydroxyalkanoic acid monomer units such as 4-hydroxybutanoic acid (4HB) and 3-hydroxyhexanoic acid (3HHx).

  The copolymer polyester block of 3HB and 3HV is preferably produced by a fermentation method, and a block copolymer obtained by addition polymerization of lactic acid to a copolymer polyester block of 3HB and 3HV produced by the fermentation method is a monomer unit. The composition ratio and arrangement are easy to control, the molecular weight adjustment is relatively easy, and it is suitable as a molded material raw resin having excellent heat resistance and mechanical strength. Moreover, this block copolymer can be produced from biomass resources such as saccharides, is also a biodegradable polymer, and is a material with a great effect of improving global environmental problems.

  In the polyester copolymer of 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 an L lactic acid monomer unit or a D lactic acid monomer unit, compared to a polymer of a racemic lactic acid monomer unit (DL) that is a mixture of L lactic acid and D lactic acid, In particular, a copolymer resin composition having an excellent thermal decomposition retention rate can be obtained. In addition, L lactic acid and D lactic acid should just be optical isomers which are not pure and have the purity which is obtained industrially.

  The polyester copolymer according to the present invention can be produced from a biomass raw material that can be easily obtained in the same manner as the polylactic acid resin composition by having the above-described configuration, and has higher heat resistance and moldability than the polylactic acid resin composition. In addition, thermal decomposition during heating can be suppressed as compared with conventionally known microorganism-produced polyhydroxyalkanoates such as poly-3-hydroxy entangled acid.

  The copolymer resin composition according to the present invention contains at least one of an olefin resin and a styrene resin. The olefin resin is preferably either a polyethylene resin or a polypropylene resin. Each of the polyethylene resin and the polypropylene resin may be a homopolymer or a copolymer with another monomer, particularly an olefin monomer. When either a polyethylene resin or a polypropylene resin is used, a copolymer resin composition having excellent impact strength and thermal decomposition retention can be obtained. Moreover, when an olefin resin is used, a copolymer resin composition having a small specific gravity can be obtained, which contributes to weight reduction and cost reduction of the product. In addition, a commercially available resin can be used for polyethylene-type resin and polypropylene-type resin, and a flame retardant, a reinforced fiber, various additives, etc. may be included. In addition, polyethylene resins and polypropylene resins have been developed for replacing raw materials with biomass raw materials, and in the future, a copolymer resin composition having a high biomass degree may be obtained.

  In the copolymer resin composition according to the present invention, the styrene resin is polystyrene, high-elastic polystyrene (HIPS), acrylonitrile-styrene copolymer resin (AS resin), methyl methacrylate-styrene copolymer resin (MS resin), acrylonitrile- It is preferably one of butadiene-styrene copolymer resins (ABS resins). Copolymer with excellent impact strength and thermal decomposition retention when it is one of polystyrene, high elasticity polystyrene (HIPS), acrylonitrile-styrene copolymer resin, methyl methacrylate-styrene copolymer resin, acrylonitrile-butadiene-styrene copolymer resin A resin composition is obtained. Moreover, although it is inferior to an olefin resin, the copolymer resin composition with small specific gravity is obtained, and it contributes to the weight reduction and cost reduction of a product. In addition, polystyrene, high elastic polystyrene (HIPS), acrylonitrile-styrene copolymer resin, methyl methacrylate-styrene copolymer resin, acrylonitrile-butadiene-styrene copolymer resin can use commercially available resins, flame retardant, reinforcing fiber, various additives An agent etc. may be included.

  Desirable content of the olefin resin and the styrene resin in the copolymer resin composition according to the present invention is 10 to 90% by mass in total, preferably 10 to 60% by mass, and more preferably 20 to 50% by mass. is there. When the content of the olefin resin and the styrene resin is large, moldability, heat resistance, and the like are improved. On the other hand, when there is little content of an olefin resin and a styrene resin, biodegradability will improve and the usage-amount of biomass resources can also be increased.

  The copolymer resin composition according to the present invention preferably further contains a crystallization nucleating agent. In particular, the crystallization nucleating agent is preferably composed of at least one selected from a talc-based nucleating agent, a nucleating agent composed 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 can be achieved. The promoting effect is excellent. In particular, when a plurality of these crystallization nucleating agents having different properties are used simultaneously, the effect is great.

  A heat stabilizer and / or a hydrolysis inhibitor, and other additives and fillers can be added to the copolymer resin composition of the present invention.

  The resin molded article according to the present invention is obtained by injection molding the above-described copolymer resin composition according to the present invention, preferably a copolymer resin composition containing a crystallization nucleating agent at a mold temperature of 50 ° C. or higher and 95 ° C. or lower. It is characterized by being molded by the method. In particular, the molded product according to the present invention is excellent as a resin molded product as a housing for an electric / electronic device. The molded product of the copolymer resin composition according to the present invention is excellent in raw material availability, mass productivity, biodegradability and the like as a general-purpose resin molded product including a housing for electrical and electronic equipment. It is also preferable from the point of consideration.

  If the mold temperature at the time of resin injection molding is about 95 ° C. or less, a water medium type temperature control apparatus with high cooling efficiency and low cost is adopted as the mold temperature control apparatus required for the injection molding process. be able to. (It is common to use an oil medium system for temperature control of molds exceeding 95 ° C.) Furthermore, if the mold temperature is low by water cooling, the mold was injected into the mold cavity. The molten resin (molded product before curing) can be cooled quickly, and the molding 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 ° C. or more and 95 ° C. or less, and further, when a crystallization nucleating agent is added, This was achieved because it was found that the process would be particularly fast.

  The method for producing a copolymer resin composition of the present invention includes a polyester production step of producing a polyester (3HB-3HV copolymer) containing a 3-hydroxybutyric acid monomer unit and a 3-hydroxyvaleric acid monomer unit by a microbial fermentation method, and the polyester And a polyester copolymer production process for producing a lactic acid-containing polyester copolymer (abbreviated as a polyester copolymer) in which lactic acid is added in a monomer unit ratio of 50 mol% to 95 mol%. A mixing step of mixing the polyester copolymer with the olefin resin or styrene resin, and preferably 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

  In the polyester production process in the method for producing a copolymer resin composition of the present invention, polyester (3HB-3HV copolymer) is produced by a microbial fermentation method. Therefore, polyester (3HB) can be easily prepared by appropriately adjusting microbial fermentation conditions. -3HV copolymer) and the ratio of 3HV monomer units to 3HV monomer units. Moreover, since it is easy to produce polyester (3HB-3HV copolymer) having a relatively high molecular weight according to the microbial fermentation method, the polyester (3HB-3HV copolymer) having a desired weight average molecular weight is obtained by hydrolysis. ) Can also be obtained.

  In the production process of a polyester copolymer for producing a lactic acid-containing polyester copolymer, a lactic acid copolymer can be produced by adding lactic acid to a polyester (3HB-3HV copolymer) adjusted to a predetermined weight average molecular weight. The lactic acid monomer unit can be blocked and introduced into the polyester. For this reason, the copolymer resin composition of the present invention makes it easy to control the ratio of the lactic acid monomer unit, and the molecular weight of the polyester copolymer, the composition ratio, the deflection temperature under load of the copolymer resin composition, the thermal decomposition retention rate, etc. 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 is preferably in the range of 99: 1 to 75:25. In the production process of polyester by the microbial fermentation method, the molar ratio of 3HB monomer unit to 3HV monomer unit in the polyester is controlled within the above range, so it has higher heat resistance than polylactic acid resin and suppresses thermal decomposition during heating. The resin composition which can be provided can be provided.

  In the method for producing a copolymer resin composition according to the present invention, the mixing ratio (mass ratio) of the olefin resin and the styrene resin to the polyester copolymer is 90:10 to 10:90, and more preferably 90:10. It is preferably in the range of 40:60, particularly 80:20 to 50:50. If the ratio of the olefin resin or styrene resin is too low, the impact resistance, thermal decomposition retention, and the effect of reducing the specific gravity cannot be sufficiently obtained, and if the ratio of the olefin resin or styrene resin is too high Biomass degree will fall. As the olefin resin or styrene resin, the resins already described may be used.

  The above-mentioned various crystallization nucleating agents may be used. The crystallization nucleating agent may be mixed at the same time when the polyester copolymer and the olefin resin or styrene resin are mixed. The mixture may be further mixed after mixing the olefin resin or styrene resin, or may be mixed with the polyester copolymer, or olefin resin or styrene resin, and then mixed after the polyester copolymer and olefin resin. Or you may mix a styrene resin.

  Various conventionally known heat stabilizers and / or hydrolysis inhibitors can be used, and among them, phenolic antioxidants, phosphite antioxidants, and carbodiimide compound hydrolysis inhibitors. At least one selected from 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.

  According to the present invention, it is possible to provide a biomass-based resin composition having sufficient heat resistance and mechanical strength, a molded article using the same, and a method for producing a biomass-based resin composition.

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

(Copolymer resin composition)
The copolymer resin composition in this embodiment is a resin composition in which a polyester copolymer and an olefin resin or a styrene resin are mixed. The monomer unit of the polyester copolymer includes three components. The monomer unit of the polyester copolymer includes a 3-hydroxybutyric acid (3HB) monomer unit represented by the following chemical formula (1), a 3-hydroxyvaleric acid (3HV) monomer unit represented by the following chemical formula (2), and the following chemical formula (3). Lactic acid (LA) monomer units shown, which are copolymerized by ester bonds.

本実施形態におけるポリエステル共重合体は、３ＨＢモノマーユニットと３ＨＶモノマーユニットとの共重合体（３ＨＢ−３ＨＶ共重合ポリエステル）に乳酸モノマーユニットがブロック共重合した構造である。本実施形態の共重合樹脂組成物は、この３成分系ポリエステル共重合体と、オレフィン系樹脂及びスチレン系樹脂の少なくとも一種とが混合された樹脂組成物である。

The polyester copolymer in the present embodiment has a structure in which a lactic acid monomer unit is block copolymerized with a copolymer of 3HB monomer units and 3HV monomer units (3HB-3HV copolymer polyester). The copolymer resin composition of this embodiment is a resin composition in which this three-component polyester copolymer is mixed with at least one of an olefin resin and a styrene resin.

(3HB-3HV copolymer polyester)
The 3HB-3HV copolymer polyester (sometimes abbreviated as 3HB-3HV polyester) 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 obtained by further copolymerizing 3hydroxyhexanoic acid (abbreviation 3HHx) to P-3HB-Co-3HV (abbreviation P-3HB-Co-3HV-Co-3HHx) Other monomer components may be included. From the viewpoint of productivity and economy, P-3HB-Co-3HV is preferably used.

The 3HB-3HV polyester according to the present invention is a kind of polyhydroxyalkanoate (abbreviation PHA), can be produced by a microbial fermentation method, and has biodegradability. 3HB-3HV polyester is preferably produced by microbial fermentation using glucose, propionic acid or the like as a carbon source from the viewpoint of easy availability of raw materials and biodegradability. Microbial fermentation method, to a microorganism having polyhydroxyalkanoate synthase produced 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 an LB medium that uses glucose as a carbon source, an MR medium, etc. that produces polyhydroxyalkanoate-producing bacteria such as Bacillus, Ralstonia, Pseudomonas, and Corynebacterium. It can be produced in two stages, cell growth and polyester production, using a culture method in which nitrogen and phosphoric acid in the medium components are limited.

  In the copolymer resin composition according to the present invention, the molar ratio of the 3HV monomer unit represented by the chemical formula (1) and the 3HV monomer unit represented by the chemical formula (2) in the polyester copolymer is 99: The range of 1 to 75:25 is preferable, and the range of 96: 4 to 80:20 is particularly preferable. By setting the molar ratio of the 3HB monomer unit to the 3HV monomer unit in the range of 99: 1 to 75:25, particularly in the range of 96: 4 to 80:20, the heat resistance of the copolymer resin composition is improved and polyester is used. It is easy to use biomass raw materials mainly composed of glucose at the time of producing the copolymer, and can take advantage of raw material procurement and manufacturing processes.

  The copolymer resin composition according to the present invention tends to improve heat resistance when the ratio of 3HB monomer units in the polyester copolymer is increased, and to improve impact resistance when the ratio of 3HV monomer units is increased. It is in. By making the molar ratio of 3HB monomer unit and 3HV monomer unit within the above range, it has mechanical strength as a general-purpose resin, has higher heat resistance than polylactic acid resin, excellent moldability, and thermal decomposition during heating The copolymer resin composition which can suppress is provided.

  The 3HB-3HV polyester according to the present invention includes other hydroxyalkanoic acid monomer units such as 4-hydroxybutanoic acid (4HB) and 3-hydroxyhexanoic acid (3HHx) in the polyester copolymer. Also good. The polyester copolymer according to the present invention is prepared by using 4-hydroxybutanoic acid (4HB), 3-hydroxyhexanoic acid (3HHx), or the like instead of the 3HV monomer unit represented by the chemical formula (2) in the polyester copolymer. The same effect can be obtained even with a polyester copolymer comprising monomer units.

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

  The addition polymerization of lactic acid to 3HB-3HV polyester may be performed by polymerizing 3HB-3HV polyester and lactic acid in an organic solvent using a polymerization initiator such as tin octylate. Adjustment of the content of the lactic acid monomer unit and the molecular weight of the lactic acid copolymer in the obtained lactic acid copolymer depends on the ratio of the raw material 3HB-3HV polyester and lactic acid, the addition amount of the polymerization initiator, the reaction temperature, the reaction time, etc. Can be controlled. Usually, a desired polyester copolymer is obtained at a reaction temperature of 100 to 150 ° C. for about 10 to 50 hours. In order to adjust the molecular weight of the polyester copolymer and the molecular weight of the 3HB-3HV copolymer polyester block in the polyester copolymer, the culture conditions may be adjusted in the above-mentioned microbial fermentation method, or the microbial fermentation method may be used. 3HB-3HV polyester may be used to achieve the desired molecular weight by hydrolysis.

  The content of the lactic acid monomer unit in the polyester copolymer is preferably in the range of 50 to 95 mol%. When the content of the lactic acid monomer unit is 50 mol% or more, the decomposition of the 3HB-3HV polyester unit in the polyester copolymer is suppressed, and the thermal decomposition retention rate of the copolymer resin composition is improved. When the content of the lactic acid monomer unit is 95 mol% or less, a copolymer resin composition having excellent heat resistance and mechanical strength as compared with the polylactic acid resin can be obtained.

  In the present invention, the lactic acid used for producing the polyester copolymer may be any lactic acid, but those produced by a conventionally known microbial fermentation method may be used. As the type of lactic acid, L lactic acid, D lactic acid, and a mixture of L lactic acid and D lactic acid (racemic body, DL body) are preferably used. In particular, it is more preferable to prepare a polyester copolymer using either L lactic acid or D lactic acid as a raw material because thermal decomposition during molding of the obtained polyester copolymer can be suppressed. In addition, L lactic acid and D lactic acid are produced by a normal industrial separation technique or synthetic technique, and may not strictly be L lactic acid or D lactic acid.

  The weight average molecular weight Mw of the polyester copolymer used in this embodiment is controlled by adjusting the molecular weight of the 3HB-3HV polyester block and adjusting the molecular weight of the polylactic acid block. The weight average molecular weight Mw of the polyester copolymer is 20,000 to 1,000,000, preferably 50,000 to 800,000, more preferably 70,000 to 400,000. 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, moldability and impact resistance are lowered, and it may not be used as a general-purpose resin molded product. Polyester copolymers having an average molecular weight exceeding 1,000,000 are not easy to produce.

(Olefin resin)
The copolymer resin composition according to the present invention contains at least one of an olefin resin and a styrene resin. The olefin resin is preferably either a polyethylene resin or a polypropylene resin. Each of the polyethylene resin and the polypropylene resin may be a homopolymer or a copolymer with another monomer, particularly with another olefin monomer. If it is either a polyethylene resin or a polypropylene resin, a copolymer resin composition having excellent impact strength and thermal decomposition retention can be obtained. In addition, a copolymer resin composition having a small specific gravity is obtained, which contributes to weight reduction and cost reduction of the product. In addition, a commercially available resin can be used for polyethylene-type resin and polypropylene-type resin, and a flame retardant, a reinforced fiber, various additives, etc. may be included. Further, development for replacing polyethylene-based resins and polypropylene-based resins with biomass raw materials has been advanced, and in the future, a copolymer resin composition having a high biomass degree will be obtained.

(Styrene resin)
In the copolymer resin composition according to the present invention, the styrene resin is polystyrene, high-elastic polystyrene (HIPS), acrylonitrile-styrene copolymer resin (AS resin), methyl methacrylate-styrene copolymer resin (MS resin), acrylonitrile- It is preferably one of butadiene-styrene copolymer resins (ABS resins). When it is any one of polystyrene, acrylonitrile-styrene copolymer resin, methyl methacrylate-styrene copolymer resin, and acrylonitrile-butadiene-styrene copolymer resin, a copolymer resin composition having excellent impact strength and thermal decomposition retention can be obtained. Moreover, although it is inferior to an olefin resin, the copolymer resin composition with small specific gravity is obtained, and it contributes to the weight reduction and cost reduction of a product. In addition, polystyrene, high elastic polystyrene (HIPS), acrylonitrile-styrene copolymer resin, methyl methacrylate-styrene copolymer resin, acrylonitrile-butadiene-styrene copolymer resin can use commercially available resins, flame retardant, reinforcing fiber, various additives An agent etc. may be included.

(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. The addition amount of the crystallization nucleating agent varies depending on the type, but is generally about 0.01 to 5 parts by mass, particularly 0.1 to 3 parts by mass with respect to 100 parts by mass of the copolymer resin composition. About mass parts are preferred. A plurality of crystallization nucleating agents having different properties can be used.

(Heat stabilizer and hydrolysis inhibitor)
A heat stabilizer and / or a hydrolysis inhibitor, and other additives and fillers can be added to the copolymer resin composition of the present invention. The heat stabilizer and / or hydrolysis inhibitor may be any heat stabilizer and / or hydrolysis inhibitor used in biomass resource-derived resins such as polylactic acid. The copolymer resin composition of the present invention contains a thermal stabilizer and / or a hydrolysis inhibitor, so that the thermal stability is high, and sufficient thermal stability is obtained even for 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. Disappears.

  The copolymer resin composition in the present invention preferably contains a heat stabilizer and / or a hydrolysis inhibitor even when the content of lactic acid monomer units in the polyester copolymer is 50 mol% or more and 95 mol% or less. . Further, when the content of the lactic acid monomer unit in the polyester copolymer is less than 50 mol%, it can be said that it is sufficient to contain a heat stabilizer and / or a hydrolysis inhibitor in the copolymer resin composition. Some decomposition can be suppressed if not.

  Examples of the heat stabilizer in the present invention include an antioxidant. Examples of the antioxidant include phenolic antioxidants, phosphite antioxidants, sulfur antioxidants, thioether antioxidants, epoxy compounds, and hydroxyamine compounds. Examples of the hydrolysis inhibitor include carbodiimide compound-based hydrolysis inhibitors (for example, trade name: Carbodilite, manufactured by Nisshinbo Chemical Co., Ltd.), isocyanate compounds, oxazoline-based compounds, epoxy compounds, epoxidized fatty acid alkyl esters, epoxidized fatty acids. A glycerin ester etc. are mentioned.

  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.

  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. For example, a more preferable effect can be expected by simultaneously using a phenolic antioxidant, a phosphite antioxidant, and a carbodiimide compound hydrolysis inhibitor. 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.

(Flame retardants)
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, “X40-9805” (trade name) manufactured by Shin-Etsu Silicone, “MB50-315” (trade name) manufactured by Dow Corning Silicone, Inc. can 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.

(Modifier)
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.

(filler)
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.

  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.

(Other additives)
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 the polyester copolymer and the olefin resin or styrene resin. Examples of the compatibilizing agent 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

(Physical properties)
-Weight average molecular weight of polyester copolymer The weight average molecular weight (Mw) of the polyester copolymer in this invention is 20,000-1,000,000, Preferably it is 70,000-800,000. The weight average molecular weight (Mw) of the polyester copolymer 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 a polyester copolymer. 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 unit of polyester copolymer The molar ratio of the lactic acid monomer unit, 3HB monomer unit, and 3HV monomer unit in the polyester copolymer in the present invention may be calculated from the measurement result of proton NMR. Similarly, the molar ratio of 3HB monomer unit and 3HV monomer unit in 3HB-3HV polyester is also calculated from the measurement result of proton NMR.

-Deflection temperature under load The heat resistance (heat resistant temperature) of the copolymer resin composition of the present invention is 65 ° C or higher. The heat resistance (heat resistant temperature) was evaluated based on the deflection temperature under load at 1.80 MPa. The deflection temperature under load is measured according to JIS K 7191-2 (1996) as described below, and general-purpose resin molded products can be used in a wide range of applications as long as the deflection temperature under load is 65 ° C. to 100 ° C. In particular, it is said to have sufficient heat resistance as a molded product as a casing for an electric / electronic device. However, in the conventional polylactic acid resin, it is not easy to make the deflection temperature under load 65 ° C. or higher even by adding a crystallization nucleating agent.

  In general, the resin composition is not limited to biomass, but can be used as long as the heat resistance is 56 ° C. or more. However, when used in a casing for electronic / electric equipment, the electronic / electric equipment is transported. It is necessary to guarantee heat resistance of 60 to 65 ° C. from the temperature environment. 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 mechanical stress is applied to the casing.

  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.

-Thermal decomposition retention rate The copolymer resin composition according to the present invention preferably has a thermal decomposition retention rate (molecular weight retention rate) of 80% or more, particularly 90% or more. When the thermal decomposition retention rate of the copolymer resin composition is 80% or more, particularly 90% or more, the property of the copolymer resin composition is hardly degraded even when heated during pelletization or molding. A maintained molded product is obtained, and can be used for various applications as a general-purpose resin molded product including a housing of an electric and electronic device. In addition, the thermal decomposition retention rate of a copolymer resin composition is represented by the decreasing rate (%) of the weight average molecular weight (Mw) when a copolymer resin composition is heated at 200 degreeC for 1 minute. Conventionally known 3HB-3HV copolymers have inferior thermal decomposition characteristics. Normally, even when a thermal stabilizer is added, the thermal decomposition retention cannot be increased to 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.
[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, since the cylinder temperature at the time of molding is 180 ° C., the test condition for the thermal decomposition retention rate is compared with 200 ° C. by adding a margin of temperature variation. Severe 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 It is preferable that the Charpy impact strength of the copolymer resin composition concerning this invention is 4 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 polyester copolymer 1>
Bacillus was cultured for 16 hours using a medium containing 5.0 g / l of peptone, 5.0 g / l of yeast extract, and 5.0 g / l of meat extract. To this culture solution, propionic acid was added to 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 separated by filtration, methanol was added to the filtrate, the bacterial cell extract was reprecipitated, filtered again and purified to prepare polyester 1. As a result of NMR analysis of the polyester 1, 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 the polyester 1 was 350,000 in standard polystyrene conversion value.

  A part of this polyester 1 was hydrolyzed with alkaline warm water to lower the molecular weight and dried. Next, polyester 1 dried by lowering the molecular weight was dissolved in anhydrous toluene so as to be 0.05 g / l, and lactic acid (L lactic acid) was 0.95 g / l and tin octylate was 0.1 g / l. After stirring at 130 ° C. for 24 hours in a nitrogen atmosphere, the mixture was further allowed to stand at 130 ° C. for 24 hours. Then, it hold | maintained for 1 hour in a vacuum atmosphere, it returned to room temperature, the obtained product was dissolved in chloroform, methanol and hexane were added, and the deposits were filtered and collect | recovered. The dissolution, precipitation, and filtration operations were repeated for purification, and finally, vacuum drying was performed to obtain a purified product. The obtained purified product was subjected to NMR analysis to confirm that it was a lactic acid copolymer, and this was designated as polyester copolymer 1.

  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 polyester copolymer 1 was 95: 4: 1. Moreover, the weight average molecular weight (Mw) by GPC method of the polyester copolymer 1 was 171,000 in standard polystyrene conversion value. The composition of the polyester copolymer 1 is summarized in Table 1. In addition, the copolymerization ratio of Table 1 represents the molar ratio of 3HB, 3HV, and LA in the polyester copolymer 1.

<Preparation of Resin Composition 1>
Next, the polyester copolymer 1 and polystyrene are melt-kneaded at a temperature ratio of 180 ° C. with a biaxial kneading extruder at a weight ratio of 60:40 to produce molding pellets having a size of about 3 mm. Composition 1 was obtained. Here, polystyrene F2 manufactured by Toyo Styrene Co., Ltd. was used as the polystyrene.

<Measurement of thermal decomposition retention rate of resin composition 1>
1 g of the 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 resin composition 1 was 97%.

<Charpy impact strength measurement of resin composition 1>
For the resin composition 1, the prepared pellets were dried at 50 ° C. for 12 hours using a shelf-type hot air dryer, and then the mold temperature was set to 80 using an electric injection molding machine with a clamping force of 50 tons. Injection molding was performed at a setting of ℃, 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 resin composition 1 was 4.2 kJ / m ² . The composition and properties of the above resin composition 1 are summarized and shown in the column of Example 1 in Table 2.

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

  Next, in <Preparation of polyester copolymer 1> in Example 1, polyester 1 was replaced with 0.05 g / l, L lactic acid 0.95 g / l, and tin octylate 0.1 g / l. A purified product was obtained in the same manner as in Example 1, except that 2 g of 0.5 g / l, L lactic acid 0.5 g / l, and tin octylate 0.1 g / l were added. The obtained purified product was subjected to NMR analysis to confirm that it was a lactic acid copolymer, and this was designated as polyester copolymer 2. 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 polyester copolymer 2 was 54: 44: 2. Moreover, the weight average molecular weight (Mw) by the GPC method of the polyester copolymer 2 was 73,000 in standard polystyrene conversion value.

<Preparation of Resin Composition 2>
Next, the polyester copolymer 2 and polypropylene are melt-kneaded at a temperature ratio of 180 ° C. by a biaxial kneading extruder at a weight ratio of 60:40 to produce molding pellets having a size of about 3 mm. Composition 2 was obtained. Here, polypropylene 2029 manufactured by Nippon Polypro Co., Ltd. was used.

<Measurement of thermal decomposition retention rate and Charpy impact strength of resin composition 2>
In the same manner as in Example 1, the thermal decomposition retention rate and Charpy impact strength of the resin composition 2 were measured, and the measurement results together with the composition of the resin composition 2 and the like were the same as in Example 1 and the examples in Table 2 Shown in column 2.

(Example 3)
<Preparation of Resin Composition 3>
For 100 parts by weight of the resin composition 2 prepared in Example 2, as a crystallization nucleating agent, crystallization nucleating agent 1 (talc nucleating agent; SG-2000 manufactured by Nippon Talc Co., Ltd.), crystallization nucleating agent 2 (nucleating 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-based nucleating agent; T-1287N made by ADEKA Corporation) were each 0 .5 parts by weight were added and melt-kneaded at a temperature of 180 ° C. with a twin-screw kneading extruder to produce molding pellets having a size of about 3 mm.

<Measurement of thermal decomposition retention rate and Charpy impact strength of resin composition 3>
In the same manner as in Example 1, the thermal decomposition retention rate and Charpy impact strength of the resin composition 3 were measured, and the measurement results together with the composition of the resin composition 3 and the like were the same as in Example 1 and the examples in Table 2 Shown in column 3.

(Comparative Example 1)
<Preparation of resin composition 4, thermal decomposition retention, and Charpy impact strength measurement>
The polyester copolymer 1 produced in Example 1 was used as the resin composition 4. In the same manner as in Example 1, the thermal decomposition retention rate and Charpy impact strength of the resin composition 4 were measured, and the measurement results are shown in the column of Comparative Example 1 in Table 3.

(Comparative Example 2)
<Preparation of resin composition 5, thermal decomposition retention, and Charpy impact strength measurement>
Polyester copolymer 2 produced in Example 2 was designated as resin composition 5. In the same manner as in Example 1, the thermal decomposition retention rate and Charpy impact strength of the resin composition 5 were measured, and the measurement results are shown in the column of Comparative Example 2 in Table 3.

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

  Next, in <Preparation of Copolyester Copolymer 1> in Example 1, polyester 1 was replaced with 0.05 g / l, L lactic acid 0.95 g / l, and tin octylate 0.1 g / l. A purified product was obtained in the same manner as in Example 1, except that 0.7 g / l of polyester 3, 0.3 g / l of L lactic acid and 0.1 g / l of tin octylate were added. The obtained purified product was subjected to NMR analysis to confirm that it was a lactic acid copolymer, and this was designated as polyester copolymer 3. 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 polyester copolymer 3 was 35: 60: 5. Moreover, the weight average molecular weight (Mw) by GPC method of the polyester copolymer 3 was 280,000 in standard polystyrene conversion value.

<Preparation of resin composition 6, thermal decomposition retention, and Charpy impact strength measurement>
Polyester copolymer 3 was designated as resin composition 6. In the same manner as in Example 1, the thermal decomposition retention rate and Charpy impact strength of the resin composition 6 were measured, and the measurement results are shown in the column of Comparative Example 3 in Table 3.

(Comparative Example 4)
<Preparation of Resin Composition 7>
Polyester copolymer 3 and the polypropylene used in Example 2 were melt-kneaded at a mass ratio of 60:40 with a twin-screw kneading extruder at a temperature of 180 ° C. to produce molding pellets having a size of about 3 mm. Resin composition 7 was obtained.

<Measurement of thermal decomposition retention rate and Charpy impact strength of resin composition 7>
In the same manner as in Example 1, the thermal decomposition retention rate and Charpy impact strength of the resin composition 7 were measured, and the measurement results were compared with the composition of the resin composition 7 and the like, as in Example 1, and the comparative examples in Table 3 Shown in column 4.

  Tables 2 and 3 show the compositions and physical property measurement results of Examples 1 to 3 and Comparative Examples 1 to 4, respectively. In the table below, the determination results in which all the two criteria are satisfied are indicated by ◯, and the criteria that does not satisfy any determination criteria are indicated by ×.

The thermal decomposition retention rates of the resin compositions 1 to 3 in Examples 1 to 3 are 94% or higher and higher than 80%, and have heat resistance even when heated in a molding process such as injection molding, and are almost deteriorated. Without being used, it can be used in many applications as a resin molded product of durable consumer materials such as electrical and electronic equipment. Further, the Charpy impact strengths of Examples 1 to 3 are ensured to be 4 kg / m ² or more, and can be used in many applications as a resin molded product of a durable consumer material such as an electric / electronic device.

On the other hand, the resin compositions 4 and 5 in Comparative Examples 1 and 2 do not contain an olefin-based resin or a styrene-based resin, and the Charpy impact strength is as low as ² kg / m ² , and the use as a molded product is limited. Use is often limited to durable consumer materials such as electrical and electronic equipment that require a certain level of impact strength.

The resin composition 6 in Comparative Example 3 has a Charpy impact strength as low as 3.6 kg / m ² and a thermal decomposition retention rate as low as 40%. By heating in a molding process such as kneading, pelletizing, or molding, The molecular weight tends to decrease, and the physical properties of the molded article may be greatly deteriorated.

  The resin composition 7 in Comparative Example 4 has a low thermal decomposition retention rate of 62%, and is likely to cause a decrease in molecular weight due to heating in a molding process such as kneading, pelletizing, or molding, and may cause deterioration of physical properties of the molded product. There is.

  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 used in image output devices such as copying machines and printers and electrical / electronic devices such as home appliances. Further, the copolymer resin composition of the present invention is an excellent product from the viewpoints of environmental problems and resource problems because a part of the raw material is obtained from the biomass material.

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 (10)

All the monomer units represented by the following chemical formulas (1), (2), and (3) are contained, and the content ratio of the monomer units represented by the following chemical formula (3) is 50 mol% or more and 95 mol% or less. A polyester copolymer;
At least one of an olefin resin and a styrene resin,
A copolymer resin composition comprising:

  The copolymer resin composition according to claim 1, wherein the olefin resin is a polyethylene resin or a polypropylene resin.   The styrenic resin is polystyrene, high elastic polystyrene (HIPS), acrylonitrile-styrene copolymer resin (AS resin), methyl methacrylate-styrene copolymer resin (MS resin), acrylonitrile-butadiene-styrene copolymer resin (ABS resin). It is either of these, The copolymer resin composition of Claim 1 or 2 characterized by the above-mentioned.   The copolymer resin composition according to any one of claims 1 to 3, 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 any one of claims 1 to 4, further comprising a crystallization nucleating agent.   6. The crystallizing nucleating agent comprises at least one 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. A copolymer resin composition.   A resin molded product, wherein the copolymer resin composition according to any one of claims 1 to 6 is injection-molded at a mold temperature of 50 ° C or higher and 95 ° 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 microbial fermentation;
A polyester copolymer production process for producing a polyester copolymer containing a lactic acid monomer by adding 50 mol% or more and 95 mol% or less lactic acid as a monomer unit ratio to the polyester;
A resin mixing step of mixing the polyester copolymer with an olefin resin or a styrene resin;
A process for producing a copolymer resin composition, comprising:   The method for producing a copolymer resin composition according to claim 8, further comprising a crystallization nucleating agent mixing step of adding and mixing a crystallization nucleating agent.   The crystallization nucleating agent comprises at least one 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. A method for producing a copolymer resin composition.