JP5509588B2 - Resin composition and molded article using the same - Google Patents

Description

  The present invention relates to a resin composition and a molded article using the same.

  In recent years, with the growing awareness of the global warming problem, technological development for reducing the use of fossil resources has been actively conducted. One such movement is to replace plastic raw materials made from petroleum with biomass materials. Resin components used in image output devices such as copiers and printers that require heat resistance and mechanical strength, and electrical and electronic devices such as home appliances, and the resin compositions that make them up are also made from biomass materials. It is desired to use a plastic.

There are several types of plastics that use biomass materials as raw materials. Currently, polylactic acid is one that is expected to provide a stable supply because of its large circulation. However, polylactic acid has a low heat distortion temperature of 50 to 60 ° C. and has a low impact resistance of 1 to 2 (kj / m ² ), so it cannot be used as a durable consumer material such as an electric product. It was.

  As a countermeasure, a method is known in which about half of a resin made from petroleum resources such as polycarbonate resin is blended with polylactic acid. For example, in cited reference 1, 20-80 parts by mass of polylactic acid, 20-70 parts by mass of polycarbonate, 0.1-50 parts by mass of reinforcing material, and 0.5-35 parts by mass of flame retardant There has been proposed an electronic device member characterized in that

  In Cited Document 2, (A) 95 to 5% by weight of polylactic acid resin, (B) 5 to 95% by weight of aromatic polycarbonate resin, and (A) and (B) in total 100 parts by weight, A resin composition comprising 0.1 to 50 parts by weight of a polymer compound obtained by adding an acrylic resin or styrene resin unit by graft polymerization and (D) 0.1 to 50 parts by weight of a flame retardant has been proposed.

  However, these resin compositions are limited even if petroleum plastic is replaced with biomass plastic. Therefore, it has been proposed to improve the mechanical strength of the resin by adding biomass fillers such as paper dust, wood flour, and natural fibers to polylactic acid. With this method, unlike the above-described blend of petroleum-based plastics, the composition ratio of the biomass material can be significantly increased.

  For example, Cited Document 3 proposes a housing material in which a natural fiber impregnated with a flame retardant and at least a biomass resin are kneaded. As natural fibers, kenaf fibers, hemp fibers, jute fibers and the like are selected.

Cited Document 4 is an electrical / electronic component formed by molding a resin composition obtained by blending 1 to 350 parts by weight of a naturally-derived organic filler with respect to 100 parts by weight of a resin derived from plant resources. An electric / electronic component is proposed in which the resource-derived resin is a polylactic acid resin, the naturally-derived organic filler 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. ing.
JP 2006-335909 A JP 2007-56247 A JP 2007-231034 A Japanese Patent Laid-Open No. 2005-23260

  As described above, an attempt has been made to impart heat resistance and mechanical strength to a resin made from a biomass material as a raw material and use it in a casing of an electric / electronic product. However, in the method using a blend of petroleum-based plastics and biomass-based plastics, there is a trade-off between increasing the proportion of biomass-based plastics used and decreasing heat resistance and mechanical strength. In order to keep above a predetermined value, the usage rate of biomass plastic cannot be increased so much. For this reason, the effect of global warming countermeasures is halved. Furthermore, with the price increase due to a future shortage of oil, the price of the petroleum-derived resin used for blending also increases in the same manner, and there is a possibility that it cannot be used substantially.

  On the other hand, if it is the method of improving the mechanical strength of resin by adding biomass type fillers, such as natural fiber and paper, to polylactic acid, the composition ratio of biomass material can be raised. However, the biomass material fiber reinforced plastic has a problem in terms of appearance and dimensional accuracy of the molded product. In Cited Document 4, in the case of paper dust, wood powder, and natural fiber, the size is about 1 to 10 mm, and the paper dust, wood powder, and natural fiber are raised on the surface of the resin part, such as an exterior part. It cannot be used for parts that require high appearance accuracy. Therefore, if paper dust, wood powder, or natural fiber is made into fine powder in order to improve the appearance accuracy, the production cost increases. On the other hand, in Cited Document 4, in order to improve heat resistance, which is another problem of polylactic acid, the addition of a crystallization nucleating agent or a plasticizer as a crystallization accelerator is added to increase the crystallinity. A method has been proposed. However, in order to crystallize polylactic acid, a molding cycle time of 90 to 100 seconds is required at a mold temperature of 100 ° C. in order to crystallize polylactic acid even when crystallization is promoted and a tensile test piece having a thickness of 3 mm is molded.

  Generally, in order to use the water-cooled mold used, it is preferable that the mold can be molded at a mold temperature of up to about 90 ° C. Further, it is said that when the molding cycle time exceeds 60 seconds, the productivity of the molded product is deteriorated and the economy is often a problem. For example, in the case of forming a tensile test piece having a thickness of 3 mm with a conventional general-purpose resin (polypropylene, polystyrene, etc.) derived from fossil resources, the mold temperature is about 50 ° C. and the molding cycle time is about 30 seconds at most.

  In view of the above problems, an object of the present invention is to increase the constituent ratio of a resin made from biomass and to economically produce a general-purpose molded product having heat resistance and mechanical strength, and this resin It is to provide a molded article using the composition.

The present invention is a resin composition containing a polyhydroxyalkanoate containing structural units represented by the following chemical formula (1) and chemical formula (2), wherein the content of 3-hydroxybutyrate (3HB) units is A resin (A) composed of the polyhydroxyalkanoate having a weight average molecular weight of 100,000 to 2,000,000 and a weight average molecular weight of 70 mol% or more and less than 90 mol% at 90 mol% or more. There is a resin composition comprising the resin (B) comprising the polyhydroxyalkanoate 100,000 2,000,000 and in that it consists of polylactic acid.
The present invention is characterized in that at least one of a compatibilizer, a plasticizer, an antioxidant, an ultraviolet absorber, a processing aid, an antistatic agent, a colorant, and a hydrolysis inhibitor is further added. It can also be set as the said resin composition.
The present invention may also be the above resin composition characterized by further blending at least one kind of plant fiber that improves mechanical strength when formed into a molded product and bacterial cellulose produced by microorganisms.

但し、ＲはＣ_ｎＨ_２ｎ＋１（ｎ＝２〜１４）である。

However, R is _{C n H 2n + 1 (n} = 2~14).

  The resin composition of the present invention is excellent in heat resistance and mechanical strength, and can increase the composition ratio of resin made from biomass, and can reduce the emission of carbon dioxide and non-biodegradable plastics. Considering environmental measures, it can also contribute to saving oil resources.

In a preferred aspect of the present invention, the resin composition is characterized in that R in the chemical formula (2) is C ₂ H ₅ .

That R in the chemical formula (2) is C ₂ H ₅ means that the polyhydroxyalkanoate is a copolymer of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV). An environmentally friendly resin composition that can increase the productivity of polyhydroxyalkanoate, has high physical properties such as heat resistance and mechanical strength, and has an increased composition ratio of resin made from biomass. Can be provided.

Preferred present invention, the polylactic acid is within the above resin composition, wherein the poly-L-lactic acid is poly-D-lactic acid, and one or more selected from stereocomplex comprising poly-L-lactic acid and poly-D-lactic acid .

  The polyhydroxyalkanoate further includes at least one selected from poly L lactic acid, poly D lactic acid, and a stereocomplex composed of poly L lactic acid and poly D lactic acid. Various physical properties such as mechanical strength can be improved, and an environmentally friendly resin composition can be provided in which the composition ratio of a general resin made from biomass is increased.

  By including 1 to 99% by mass of the polyhydroxyalkanoate, various physical properties such as low heat resistance and mechanical strength of polylactic acid can be improved, and the composition ratio of resin using biomass as a raw material is increased. In addition, an environmentally friendly resin composition can be provided.

  The present invention is preferably the resin composition further including a crystallization nucleating agent.

  By further including a crystallization nucleating agent in the resin composition, the crystallization speed of the polyhydroxyalkanoate can be increased, the molding cycle time can be shortened, and high productivity can be achieved using an environmentally friendly resin composition. It is possible to produce a resin molded product having high heat resistance and high strength at low cost.

  In a preferred aspect of the present invention, the crystallization nucleating agent is one or more 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. The resin composition.

  The crystallization nucleating agent comprises at least one selected from a talc nucleating agent, a nucleating agent made of a metal salt-based material having a phenyl group, and a benzoyl compound nucleating agent. It has the effect of increasing the conversion rate. As a result, the molding cycle time can be greatly shortened, and a resin molded product can be produced at low cost by using an environmentally friendly resin composition.

  The present invention is a molded product obtained by molding any one of the above resin compositions at a mold temperature of 50 to 90 ° C. by an injection molding method. In general, the mold temperature in injection molding or the like is represented by a mold exit temperature of a mold cooling medium (water or oily medium).

  If the mold temperature is 90 ° C. or lower, an aqueous medium system can be adopted as a mold temperature control apparatus required for molding, and thus molding can be performed with a simple apparatus (90 When the temperature is higher than ℃, it is common to use the oil medium method.) Also, if the mold temperature is low, the molten resin filled in the mold can be cooled quickly, and the molding cycle Time can be shortened. This is because, unlike polylactic acid, crystallization of polyhydroxyalkanoate proceeds relatively fast in the temperature range of 50 ° C. to 90 ° C., and further, when a crystallization nucleating agent is added, crystallization rapidly occurs in this temperature range. Can be realized to be faster.

  The present invention is preferably the molded article provided in an electric / electronic device.

  The molded product of the present invention can be used for casings and members of electric and electronic equipment, and even for durable consumer materials that could not be realized up to now, the composition ratio of the resin made from biomass was increased, giving consideration to the environment. It can be provided using a resin composition.

  According to the present invention, a resin composition capable of increasing the component ratio of a resin made from biomass and economically producing a general-purpose molded product having heat resistance and mechanical strength, and molding using this resin composition Goods can be provided.

[Resin composition]
(Polyhydroxyalkanoate (resin (A), resin (B)))
The polyhydroxyalkanoate (resin (A), resin (B)) in the present invention is preferably poly-3hydroxyalkanoate (P3HA) produced by a microorganism using a biomass material as a raw material. Among poly (3hydroxyalkanoates) (P3HA), a copolymer of 3hydroxybutyrate (3HB) and 3hydroxyvalerate (valeric ester) (3HV) is preferable from the viewpoint of raw materials and productivity.

  Poly-3hydroxybutyrate (P3HB) can be produced by Pseudomonas, Ralstonia, Bacillus, and Corynebacterium in LB medium, MR medium, etc. using glucose as a carbon source.

In order to produce polyhydroxyalkanoate (resin (A) or resin (B)) containing 3-hydroxybutyrate (P3HB), the P3HB production medium containing glucose corresponds to the other target hydroxyalkanoate. The organic acid having the carbon number to be added is added as a culture substrate. For example, as a preferred polyhydroxyalkanoate embodiment, a 3hydroxybutyrate-3hydroxyvalerate copolymer (P (3HB-Co), which is a copolymer of 3hydroxybutyrate (3HB) and 3hydroxyvalerate (3HV), is used. for -3HV)) production and P3HB production medium containing glucose, may be added to propionic acid _{(C 3} carboxylic acid) as a culture substrate. By adjusting glucose and propionic acid to be added to the production medium, 3hydroxybutyrate and 3hydroxyvalerate in 3hydroxybutyrate-3hydroxyvalerate copolymer (P (3HB-Co-3HV)) You can control the ratio. In general, P (3HB-Co-3HV) is a cell growth process by using a production method such as Bacillus, Ralstonia, Pseudomonas, etc., by limiting the nitrogen and phosphate in the medium components. And polyester in two stages of production process.

Further, by giving an even number of fatty acids of C ₆ or more to a microorganism having a polyhydroxyalkanoate PHA synthase gene derived from the genus Bacillus, a 3 hydroxybutyrate-3 hydroxyhexanoate copolymer (P (3HB- Co-3HHx)) can be synthesized.

  The alkyl group R in the chemical formula (2), which is a structural unit of polyhydroxyalkanoate (PHA), is n = 2 to 14. However, from the viewpoint of the effect of improving heat resistance and ease of production, n = 2 to 4 In particular, from the viewpoint of ease of production, n = 2 corresponding to 3 hydroxyvalerate (3HV) is preferable.

  In the present invention, the resin (A) comprising polyhydroxyalkanoate (PHA) has a content of 3-hydroxybutyrate (3HB) units in PHA of 90 mol% or more. Moreover, the weight average molecular weight Mw of resin (A) is 10-2 million by the standard polystyrene conversion value by GPC analysis, Preferably it is 200-1,800,000, More preferably, it is 500-1,500,000. If it is said range, production by microorganisms is possible and there is no problem also in the moldability and heat resistance of the resin composition of this invention.

  In the present invention, the resin (B) comprising polyhydroxyalkanoate is adjusted so that the content of 3HB units in PHA is 70 mol% or more and less than 90 mol%. Moreover, the weight average molecular weight Mw of resin (B) is a standard polystyrene conversion value by GPC analysis, and is 10-2 million, Preferably it is 200-1,800,000, More preferably, it is 500-1,500,000. If it is said range, production by microorganisms is possible and there is no problem also in the moldability and heat resistance of the resin composition of this invention.

(Polylactic acid)
The polylactic acid used in the present invention may be any polylactic acid, but is composed of poly-L lactic acid, poly-D lactic acid, and poly-L lactic acid and poly-D lactic acid produced by a conventionally known microbial production method. Those containing any of the stereocomplexes are preferably used. Of course, a mixture of these polylactic acids may be used. Since many commercially available polylactic acids are known, these may be used. The weight average molecular weight Mw of polylactic acid is a standard polystyrene conversion value by GPC analysis, and is preferably 5 to 500,000, more preferably 10 to 250,000.

(Crystal nucleating agent)
The crystallization nucleating agent used in the present invention may be any crystallization nucleating agent used in a thermoplastic resource 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.

(Additive)
Various additives such as compatibilizers, plasticizers, antioxidants, ultraviolet absorbers, processing aids, antistatic agents, colorants, hydrolysis inhibitors, and the like are appropriately added to the resin composition used in the present invention. You can also 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 compatibilizer is not particularly limited as long as it functions as a compatibilizer for resin (A), resin (B), and polylactic acid. 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. As the hydrolysis inhibitor, known ones can be used without particular limitation, and examples thereof include polycarbodiimide resins.

(Plant fiber, etc.)
In the resin composition of the present invention, the mechanical strength of a molded product can be improved by blending and molding a vegetable fiber 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. 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. Also, the type of plant is not particularly limited. Considering harmony with the environment, such as fast-growing plants such as jute, kenaf, bamboo, rice straw after harvesting edible parts, corn, and sugar cane. Therefore, it is desirable to select the blend and blend ratio as appropriate.

(Preparation of resin composition)
Resin (A) made of the above polyhydroxyalkanoate, resin (B) made of polyhydroxyalkanoate, polylactic acid, and if necessary, a crystallization nucleating agent (C), other additives, plant fibers, etc. Is mixed and kneaded by a kneading extruder or the like in a predetermined ratio to form pellets of the resin composition used in the present invention. The kneading extruder may be a normal single-screw kneading extruder or biaxial kneading extruder for petroleum resins, and may be kneaded at a kneading temperature of about 180 degrees and pelletized. There is no restriction | limiting in the mixing ratio of resin (A) and resin (B), and the mixing ratio of polylactic acid. For example, a resin mixture containing 10 to 60 parts by mass of resin (A), 30 to 60 parts by mass of resin (B), and 30 to 70 parts by mass of polylactic acid is prepared. It is preferable to add 0.5 to 5 parts by mass of C). In addition, when the mixing ratio of polylactic acid in the resin composition exceeds 90% by mass, the heat resistance may not be sufficient, or there may be an undesirable situation such as an increase in molding temperature during molding or a prolonged molding time.

[Molding of thermoplastic resin]
If the pellets of the resin composition produced as described above are injection-molded in the same manner as petroleum-based resins with a normal petroleum-based resin injection molding machine, the molded article of the present invention can be produced. If it is a general molded article, the mold temperature in molding may be 40 to 90 ° C., and the cooling time may be 10 to 60 seconds. As the mold, a water-cooled cooling device for petroleum resin can be used.

  In addition, the molding method in the resin composition of the present invention is not limited only to the injection molding method. For example, any molding method such as press molding, extrusion molding, foam molding, hollow molding, or the like is a problem. There is no. Moreover, you may use the above-mentioned additive at the time of shaping | molding.

[Example]
(Production of Resin (A) and Resin (B) Consisting of Polyhydroxyalkanoate)
<Preparation of resin (A1)>
Using a Bacillus bacterium, a nitrogen source was limited in a culture solution cultured for 16 hours in a medium (pH 6.95) containing peptone 5.0 g / L, yeast extract 5.0 g / L, and meat extract 5.0 g / L. Glucose and propionic acid were added to the minimal medium and cultured at 45 ° C. for 48 hours to obtain wet cells. The obtained wet cells were lyophilized, and 80 times the amount of chloroform as the amount of dry cells was added, and the cells were extracted at 80 ° C. Insoluble matter was filtered off, methanol was added to the filtrate to reprecipitate the cell extract, and the precipitate was filtered to obtain a purified product. The polymer content in the microbial cells was 30 to 50 wt%.

The minimum medium composition is Na ₂ HPO ₄ · 12H ₂ O 9.0 g / L, KH ₂ PO ₄ 1.5 g / L, NH ₄ Cl 0.5 g / L, MgSO ₄ · 7H ₂ O 0.2 g / L, Trace Element is 1.0 ml / L. Trace elements _{FeCl 3 9.7g / L, CaCl 2} 7.8g / L, CoCl 2 · 6H2O 0.218g / L, CuSO 4 · 5H 2 O 0.156g / L, NiCl3 · 6H 2 O 0.118g / L, CrC l3 · 6H ₂ O 0.105 g / L dissolved in 0.1 M HCl.

  The purified product is dissolved in deuterated chloroform, and by NMR analysis, it is a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate (P (3HB-Co-3HV)), and 3-hydroxybutyrate (3HB) Was confirmed to be 0.975 (97.5 mol%). The obtained P (3HB-Co-3HV) was used as resin (A1). The weight average molecular weight Mw of the resin (A1) was 1.4 million.

<Preparation of Resin (A2), (B1), (B2)>
Resins (A2), (B1), and (B2) were prepared in the same manner as the resin (A1) except that the glucose and propionic acid added to the medium were adjusted in the preparation of the resin (A1). . The resin (A2) to which propionic acid was not added in the medium was a homopolymer of 3-hydroxybutyrate. Resins (B1) and (B2) are copolymers of 3-hydroxybutyrate and 3-hydroxyvalerate (P (3HB-Co-3HV)), each of 3-hydroxybutyrate (3HB). Were confirmed to be 0.85 (85 mol%) and 0.70 (70 mol%). The weight average molecular weights Mw of the resins (A2), (B1), and (B2) were 700,000, 2 million, and 1.8 million, respectively. Moreover, each polymer content in a microbial cell was 30-50 wt%.

[Example 1]
(Preparation of pellet (1) of resin composition)
50 parts by mass of the prepared resin (A1) and 50 parts by mass of the resin (B1) are mixed, and the plasticizer, heat stabilizer, antioxidant, hydrolysis inhibitor, etc., as in the case of petroleum-based plastics. Various additives were added as appropriate, dry blended, and then melt kneaded at a temperature of 180 ° C. with a single-screw kneading extruder to produce a resin composition pellet (1) of about 3 mm square. Table 1 shows the blending ratio of the pellet (1). In Table 1, the amount of various additives excluding the crystallization nucleating agent is omitted because it is small.

（樹脂組成物の成形）
作製したペレット（１）を、棚式の熱風乾燥機を用いて５０℃で１２時間乾燥した後、型締力５０トンの電動式射出成形機を使用して、金型温度８０℃、シリンダー温度１８０℃、射出速度２０ｍｍ／ｓ、射出圧力１００ＭＰａ、冷却時間３０ｓｅｃの設定で成形品（荷重たわみ温度試験用の短冊試験片）を作製した。作製した短冊試験片のサイズは、長さ１３０ｍｍ、幅３．２ｍｍ、高さ１２．７ｍｍである。

(Molding of resin composition)
The produced pellet (1) was dried for 12 hours at 50 ° C. using a shelf-type hot air dryer, and then the mold temperature was 80 ° C. and the cylinder temperature was used using an electric injection molding machine with a clamping force of 50 tons. A molded article (a strip test piece for a deflection temperature test under load) was produced at 180 ° C., an injection speed of 20 mm / s, an injection pressure of 100 MPa, and a cooling time of 30 sec. The size of the produced strip test piece is 130 mm in length, 3.2 mm in width, and 12.7 mm in height.

  A molded product (Izod impact test specimen) was formed in the same manner as the strip specimen for the deflection temperature test under load except that the mold was changed to the production of an Izod impact test specimen and the cooling time was 120 sec. ) Was produced. The size of the prepared test piece is a No. 2 A test piece having a length of 64 mm, a width of 12.7 mm, a thickness of 12.7 mm, and an A notch.

(Load deflection temperature test)
A load deflection temperature test in accordance with JIS K 7191 was performed using the strip test piece for the load deflection temperature test. The distance between the fulcrums was 100 mm, the temperature increase rate was 2 ° C./min, and the bending stress was 0.45 MPa. The measured deflection temperatures under load are shown in Table 1.

(Izod impact test)
The prepared Izod impact test specimen was subjected to an Izod impact test in accordance with JIS K 7110. The results are shown in Table 1.

[Examples 2 to 4]
The prepared resins (A1), (B1), (B2), polylactic acid resin, and crystallization nucleating agent were blended in the proportions shown in Table 1, respectively, and various additives were appropriately added in the same manner as in Example 1. After dry blending, the mixture was melt-kneaded with an extruder to produce pellets (2) to (4) of a resin composition of about 3 mm square. In Table 1, the crystallization nucleating agent is shown in parts by mass as an external number with respect to 100 parts by mass of the resin component. Moreover, since the compounding quantity of various additives except a crystallization nucleating agent is small, description is abbreviate | omitted. Here, poly L-type lactic acid (Lacia H-100 manufactured by Mitsui Chemicals, Inc.) was used as the polylactic acid resin. The crystallization nucleating agent 1 is zinc phenylphosphonate (C ₆ H ₅ PO ₃ Zn), and the crystallization nucleating agent 2 is hydrous magnesium silicate ((OH) ₈ Mg ₁₂ Si having an average particle size of 1.0 μm). ₁₆ O ₄₀ , or (OH) ₂ Mg ₃ (Si ₂ O ₅ ) ₂ ), and the crystallization nucleating agent 3 is octanedicarboxylic acid-dibenzoylhydrazide (C ₂₄ H ₃₀ N ₄ O ₄ ).

  Using the prepared pellets (2) to (4), in the same manner as in Example 1, a strip test piece for a load deflection temperature test and a test piece for an Izod impact test were prepared, respectively, and a load deflection temperature test, And an Izod impact test. The measurement results are shown in Table 1 for each example.

[Comparative Examples 1-4]
The prepared resins (A1), (A2), (B2), polylactic acid resin, and crystallization nucleating agent were blended in the proportions shown in Table 1, respectively, and in the same manner as in Example 4, pellets (5) to ( 8), and from these, in the same manner as in Example 1, a strip test piece for a deflection test under load and a test piece for an Izod impact test were prepared, and a deflection test under load and an Izod impact test were conducted. Carried out. The measurement results are shown in Table 1 for each comparative example.

[Consideration of results]
As can be seen from Examples 1 to 4, the molded article using the resin composition of the present invention has a deflection temperature under load of 95 ° C. or higher and an Izod impact strength of 5 kJ / m ² or higher. For this reason, it is thought that the resin composition of this invention has the heat resistance and impact strength which can be utilized for many uses as a general-purpose resin molded product including the housing | casing of an electrical / electronic device.

  Examples 1 to 4 and Comparative Examples 1 to 4 will be specifically described. As shown in Comparative Example 1, in a molded product containing only a polylactic acid resin, the deflection temperature under load and the Izod impact strength are very low values. (Comparative Example 1) is blended with the resin (A) and the resin (B) (Examples 2 and 4), and the blend composition of the resin (A) and the resin (B) (Examples 1 and 3). High deflection temperature under load and Izod impact strength. Molded articles using the resin composition in which the crystallization nucleating agent is added only to the resin (A) (Comparative Examples 2 and 3) have a high deflection temperature under load, but have a low Izod impact strength, and are crystallized only in the resin (B). A molded article using a resin composition to which a nucleating agent is added (Comparative Example 4) has a high Izod impact strength but a low deflection temperature under load, and a blend composition of resin (A) and resin (B) (Example) 1, 3) and a blended composition obtained by adding a polylactic acid resin to these (Examples 2 and 4) could not be obtained with a well-balanced and suitable physical property. In addition, it can be seen that the molded article using the resin composition to which the crystallization nucleating agent is added improves both the deflection temperature under load and the Izod impact strength compared with the case where the crystallization nucleating agent is not added.

Claims (7)

A resin composition containing a polyhydroxyalkanoate containing structural units represented by the following chemical formula (1) and chemical formula (2):
Resin (A) comprising the polyhydroxyalkanoate having a 3-hydroxybutyrate (3HB) unit content of 90 mol% or more and a weight average molecular weight of 100,000 to 2,000,000, and the content of the 3HB unit is less than 70 mol% to 90 mol%, the resin (B) having a weight average molecular weight is from the polyhydroxyalkanoate 100,000 2,000,000 resin composition characterized in that it consists of polylactic acid.

(Wherein, R is _{C n H 2n + 1 (n} = 2~14).) 2. The system according to claim 1, further comprising at least one of a compatibilizer, a plasticizer, an antioxidant, an ultraviolet absorber, a processing aid, an antistatic agent, a colorant, and a hydrolysis inhibitor. The resin composition as described. The resin composition according to claim 1 or 2, further comprising at least one of plant fibers that improve the mechanical strength of the molded article and bacterial cellulose produced by microorganisms . The said polylactic acid is one or more selected from poly L lactic acid, poly D lactic acid, and the stereocomplex which consists of poly L lactic acid and poly D lactic acid , The any one of Claims 1-3 characterized by the above-mentioned. The resin composition as described. The resin composition according to any one of claims 1 to 4, characterized in that further includes a crystallization nucleating agent.   A molded product, wherein the resin composition according to any one of claims 1 to 5 is molded at a mold temperature of 50 to 90 ° C by an injection molding method.   The molded article according to claim 6, which is provided in an electric / electronic device.