JP2006137854A - Resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition having excellent impact resistance and heat resistance and comprising a poly(3-hydroxybutylate)-based polymer and a thermoplastic polyurethane. <P>SOLUTION: The resin composition comprises 50-99 wt.% poly(3-hydroxybutylate)-based polymer, and 50-1 wt.% thermoplastic polyurethane and satisfies the following requirements (a) to (d): (a) the glass transition temperature is (-30)-(-50)°C; (b) the JIS A surface hardness is ≥60 and ≤95; (c) the crystallization temperature when being heated from room temperature to 180°C at 80°C/min rate, kept at 180°C for 1 min and cooled at 10°C/min temperature-dropping rate by a differential scanning calorimeter is ≥110°C and ≤170°C; and (d) the weight average molecular weight (Mw) expressed in terms of polystyrene when a chloroform-dissolved component is measured by a gel-permeation chromatography is ≥100,000 and ≤3,000,000. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin composition comprising a poly-3-hydroxybutyrate polymer and a thermoplastic polyurethane, and more specifically, a poly-3-hydroxybutyrate polymer excellent in impact resistance and heat resistance, and a heat The present invention relates to a resin composition comprising a plastic polyurethane.

  Since poly-3-hydroxybutyrate polymers are obtained from plants as raw materials, they have recently attracted attention as materials with little environmental impact. However, the poly 3-hydroxybutyrate polymer has a problem that it is inferior in impact resistance.

  As a method for solving this problem, a method of mixing polycaprolactone or polybutylene succinate resin has been proposed (for example, see Patent Documents 1 and 2).

JP-A-9-194281 (first page) JP 11-323141 A (first page)

  However, in the method of mixing the different polymers proposed in Patent Documents 1 and 2, the impact resistance is not sufficient and the heat resistance is low.

  Therefore, the present invention provides a resin composition comprising a poly-3-hydroxybutyrate polymer and a thermoplastic polyurethane excellent in heat resistance and impact resistance.

  As a result of intensive studies to solve the above problems, the present inventors have found that a resin composition comprising a poly-3-hydroxybutyrate polymer and a specific thermoplastic polyurethane exhibits excellent impact resistance and heat resistance. The present invention has been completed.

That is, the present invention comprises 50 to 99% by weight of a poly 3-hydroxybutyrate polymer and 50 to 1% by weight of a thermoplastic polyurethane that satisfies the requirements of (a) and (b). The present invention relates to a resin composition that satisfies the requirements shown in (d).
(A) The glass transition temperature when heated at a rate of temperature increase from −100 ° C. to 10 ° C./min with a differential scanning calorimeter is −30 to −50 ° C.
(B) JIS A surface hardness is 60 or more and 95 or less.
(C) Crystal in a differential scanning calorimeter when heated from room temperature to 180 ° C. at a heating rate of 80 ° C./min, held at 180 ° C. for 1 minute, and then cooled at a cooling rate of 10 ° C./min. The conversion temperature is 110 ° C. or higher and 170 ° C. or lower.
(D) The polystyrene-reduced weight average molecular weight (Mw) is from 100,000 to 3,000,000 when the chloroform-dissolved component is measured by gel permeation chromatography.

  The present invention is described in detail below.

  Examples of the poly-3-hydroxybutyrate polymer (hereinafter referred to as “PHB polymer”) used in the present invention include poly-3-hydroxybutyrate homopolymer, 3-hydroxybutyrate and 3-hydroxybutyrate. And a copolymer with a hydroxyalkanoate other than the rate. Examples of hydroxyalkanoates other than 3-hydroxybutyrate when the PHB polymer is a copolymer include, for example, 3-hydroxypropionate, 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyhepta Noate, 3-hydroxyoctanoate, 3-hydroxynonanoate, 3-hydroxydecanoate, 3-hydroxyundecanoate, 4-hydroxybutyrate, hydroxylaurylate. Further, as the copolymer, since a resin composition excellent in molding processability can be obtained, it is preferable that a hydroxyalkanoate other than the 3-hydroxybutyrate is copolymerized in an amount of 25 mol% or less. preferable.

  The PHB polymer used in the present invention includes, in particular, poly-3-hydroxybutyrate homopolymer, 3-hydroxybutyrate / 3-hydroxyvalerate copolymer, 3-hydroxybutyrate / 4-hydroxybutyrate. Copolymers are preferred because they are readily available.

  Moreover, since it becomes a resin composition excellent in molding processability, it is preferable that the PHB-based polymer is produced in a microorganism. Such a PHB polymer can be obtained as a commercial product. Moreover, as the manufacturing method, it can also obtain by the method currently disclosed by the US Patent 4477654 gazette, the international publication 94/115519 gazette, the US Patent 5502273 gazette, etc., for example.

  The thermoplastic polyurethane used in the present invention has a glass transition temperature when heated at a rate of temperature increase from −100 ° C. to 10 ° C./min with a differential scanning calorimeter (hereinafter referred to as “DSC”). Is -30 to -50 ° C, and (b) JIS A surface hardness measured according to JIS K7311 is 60 or more and 95 or less. The resin composition of this invention turns into a resin composition excellent in impact resistance and heat resistance by using the thermoplastic urethane which concerns.

  The thermoplastic polyurethane used in the present invention is not particularly limited as long as the above (a) and (b) are satisfied. Above all, since the resulting resin composition has excellent impact resistance, adipic acid ester is used for the soft segment. It is preferable to use an adipic acid-based thermoplastic polyurethane, and an adipic acid thermoplastic polyurethane using ethylene glycol and / or butylene glycol as the adipic acid ester of the soft segment is more preferable.

  As such a thermoplastic polyurethane, for example, (trade name) Miractolan E190 (manufactured by Nippon Miractolan Co., Ltd.) can be obtained as a commercial product.

  The resin composition of the present invention comprises 50 to 99% by weight of the PHB polymer and 50 to 1% by weight of the thermoplastic polyurethane, and 60 to 95% by weight of the PHB polymer and the thermoplastic polyurethane 40. ˜5 wt% is preferable, and 65 to 90 wt% of the PHB polymer and 35 to 10 wt% of thermoplastic polyurethane are more preferable. Here, when the weight ratio of the thermoplastic polyurethane is less than 1% by weight, the resulting resin composition is inferior in impact resistance. On the other hand, when it exceeds 50 weight%, the resin composition obtained becomes inferior to heat resistance.

  Furthermore, the resin composition of the present invention was heated from room temperature to 180 ° C. at a temperature increase rate of 80 ° C./min in DSC, held at 180 ° C. for 1 minute, and then at a temperature decrease rate of 10 ° C./min. The cooled crystallization temperature is 110 ° C. or higher and 170 ° C. or lower, preferably 115 ° C. or higher and 160 ° C. or lower, and more preferably 120 ° C. or higher and 150 ° C. or lower. Here, when the crystallization temperature is less than 110 ° C., the resulting resin composition has a low crystallization rate and inferior production efficiency when formed into a molded product. On the other hand, it is practically difficult to obtain a resin composition having a crystallization temperature exceeding 170 ° C. The crystallization temperature is an aluminum pan loaded with 5 mg of sample in DSC (Perkin Elmer, trade name DSC-7) measurement, and the pan is heated from room temperature to 80 ° C./min. This is the highest temperature among the peak temperatures of heat flux based on crystallization observed when heated to 180 ° C., held at 180 ° C. for 1 minute, and then cooled at a temperature decrease rate of 10 ° C./min.

  The resin composition of the present invention has a polystyrene-reduced weight average molecular weight (hereinafter referred to as Mw) of 100000 or more and 3000000 or less when (d) a chloroform-dissolved component is measured by gel permeation chromatography (hereinafter referred to as GPC). In particular, it is preferably 120,000 to 1,000,000. Here, when Mw is less than 100,000, the obtained resin composition is inferior in mechanical strength. On the other hand, when Mw exceeds 3000000, the obtained resin composition is inferior in molding processability. In addition, Mw of the chloroform melt | dissolution component of a resin composition can also be measured by the molecular weight of the melt | dissolution part obtained by melt | dissolving a resin composition or its molding in 60 degreeC chloroform for 2 hours. In addition, the measurement of Mw in the present invention uses a GPC apparatus (manufactured by Tosoh Corporation, trade name HLC8020GPC) equipped with two columns (trade name TSKgel GMHHR-H, manufactured by Tosoh Corporation) and measuring solvent: chloroform. Using a standard polystyrene (manufactured by Tosoh Corporation), the column elution volume was measured at a measurement temperature of 40 ° C., a sample dissolution condition: 60 ° C., and a sample prepared at a measurement concentration of 50 mg / 50 mL in 2 hours with an injection volume of 100 μL. This was calibrated.

  Since the resin composition of the present invention exhibits particularly excellent moldability, the phthalic acid plasticizer 0.1 to 0.1 parts by weight with respect to the total amount of 100 parts by weight of the PHB polymer and the thermoplastic polyurethane. It preferably comprises 30 parts by weight. As the phthalic acid plasticizer, those that lower the crystal melting point of the PHB polymer by 3 ° C. or more are preferable. The phthalic acid plasticizer is not particularly limited. For example, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, di-2-ethylhexyl phthalate (DOP), dibutylbenzyl phthalate, dicyclohexyl phthalate, dimethylcyclohexyl phthalate These may be used, and one or more of these may be used in combination.

  Since the resin composition of the present invention exhibits excellent heat resistance, it is preferable that the PHB polymer forms a sea-island structure with a continuous phase and thermoplastic polyurethane with a dispersed phase. Furthermore, it is preferable that the average particle size of the dispersed phase is 0.1 to 3 μm because excellent impact resistance is exhibited.

  Examples of the shape of the resin composition of the present invention include a pellet shape, a powder shape, a lump shape, and the like. Among them, the pellets are excellent in production efficiency at the time of manufacture and excellent in handleability at the time of molding. The shape is preferred. As a method for forming a pellet, for example, a strand cutting method of cutting a strand-shaped molten granulated product with a strand cutter, an underwater cutting method of cutting a molten resin in water, or cutting the molten resin as it is or by cooling with mist or the like Examples include the hot-cut method and the sheet pelletizing method in which a sheet-shaped molten granule is cut with a sheet pelletizer. Among them, strand cutting is particularly possible because pellets with good resin bite can be obtained during injection molding and extrusion molding. Method, underwater cut method and hot cut method are preferably used.

  As a method for producing the resin composition of the present invention, any method and apparatus may be used as long as the PHB polymer and the thermoplastic polyurethane can be mixed. Among them, production efficiency is particularly good, and molding processability is improved. Since an excellent resin composition can be obtained, it is preferable to produce using a kneader whose temperature is set so that the temperature of the molten resin discharged from the die of the extruder is 160 ° C. or higher and 185 ° C. or lower. Examples of the kneader to be used include a different-direction twin-screw extruder such as a same-direction twin-screw extruder and a conical twin-screw extruder; a batch mixer such as a Banbury mixer and a pressure kneader; and a roll kneader.

  When the resin composition of the present invention is produced, it is desirable to dry the PHB polymer and the thermoplastic polyurethane in advance, and the drying conditions are not particularly limited, for example, 30 to 40 to 90 ° C. It is preferable to dry for about minutes to 3 days. Also, when molding the resin composition of the present invention, it is desirable to dry the resin composition in advance, and the drying conditions are not particularly limited, for example, at a temperature of 40 to 90 ° C. for 30 minutes. It is preferable to dry for about 3 days.

  The molding method of the resin composition of the present invention is not particularly limited, and examples thereof include profile extrusion, film, sheet, blow, injection, foaming, extrusion coating, and rotational molding. Among these, injection molding is a preferable example. In the case of performing injection molding, if the temperature of the molten resin is 230 ° C. or lower, preferably 210 ° C. or lower, the time required for crystallization in the mold is small, and the molding cycle can be shortened.

  You may add a filler to the resin composition of this invention. There is no particular limitation on the filler to be added, for example, calcium carbonate, mica, talc, silica, barium sulfate, calcium sulfate, kaolin, clay, pyroferrite, bentonite, sericanite, zeolite, nepheline cinnite, attapulgite, wollastonite, ferrite , Inorganic filler such as calcium silicate, magnesium carbonate, dolomite, antimony trioxide, titanium oxide, iron oxide, molybdenum disulfide, graphite, gypsum, glass beads, glass powder, glass balloon, glass fiber, quartz, quartz glass, montmorillonite Materials: Various plant fibers such as starch, cellulose fiber and kenaf; natural fillers such as wood flour, okara, fir shell, bran, and organic fillers such as modified products thereof.

  Among them, calcium carbonate and talc also have a function of increasing the crystallization speed, so it is desirable to add them, and talc is particularly preferable. Moreover, in order to improve the dispersibility in the resin composition of the present invention, it is also possible to use surface-modified calcium carbonate, talc, or clay. When a filler is added, the resin composition has an excellent balance between rigidity and impact resistance, so that it is desirably used in an amount of 100 parts by weight or less based on 100 parts by weight of the resin composition of the present invention.

  Furthermore, fatty acids, aliphatic esters, aliphatic amides, and fatty acid metal salts can be added to the resin composition of the present invention.

  In addition, the resin composition of the present invention may contain a crystal nucleating agent as necessary, which further increases the crystal growth rate. Examples of the crystal nucleating agent include boron nitride, mica, talc, alumina, calcium hydroxyapatite, aluminum chloride, and clay. Among these, talc and boron nitride are preferable.

  Furthermore, the resin composition of the present invention includes an anti-hydrolysis agent typified by carbodiimide, an anti-blocking agent, a release agent, an antistatic agent, a slip agent, an antifogging agent, a lubricant, a heat stabilizer, and an ultraviolet ray as necessary. Stabilizers, light stabilizers, weathering stabilizers, antifungal agents, rust inhibitors, ion trap agents, foaming agents, flame retardants, flame retardant aids, and the like may be included. Furthermore, other thermoplastic resins and rubbers, particularly thermoplastic resins called biodegradable resins may be blended.

  The resin composition of the present invention is used for the housing and structure of electrical products; automotive exterior parts such as bumpers, rocker moldings, side moldings, and over fenders; automotive interior parts such as carpets, head liners, door trims, sun visors, etc. For example, it is suitably used.

  The resin composition of the present invention is excellent in heat resistance and impact resistance.

  Hereinafter, the present invention will be described with reference to examples, but these are illustrative and the present invention is not limited to these examples.

  Various measurements in Examples and Comparative Examples are shown below.

(Measurement of crystallization temperature)
The crystal growth rate was measured using a differential scanning calorimeter (manufactured by Perkin Elmer, trade name DSC-7). A 5 mg sample is cut from the pellet and loaded into an aluminum pan. The pan is heated from room temperature to 180 ° C. at a heating rate of 80 ° C./min and held at 180 ° C. for 1 minute. Then, it cooled at the speed | rate of 10 degree-C / min, and made the highest temperature among the peak temperature of the heat flux based on crystallization the crystallization temperature.

(Measurement of crystal melting point)
The crystal melting point was measured using a differential scanning calorimeter (trade name DSC-7, manufactured by Perkin Elmer). A 5 mg sample is cut from the pellet and loaded into an aluminum pan. The highest temperature among the peak temperatures of heat flux based on crystal melting observed when the pan was heated from room temperature at a heating rate of 10 ° C./min was defined as the crystal melting point.

(Measurement of weight average molecular weight)
The molecular weight was measured by gel permeation chromatography using only the dissolved components obtained by dissolving the pellets obtained by granulation in chloroform at 60 ° C. for 2 hours. Calibration was performed using standard polystyrene (manufactured by Tosoh Corporation), and the weight average molecular weight (Mw) was determined in terms of polystyrene. The measurement conditions are shown below.

Model: Product name HLC8020GPC (manufactured by Tosoh Corporation)
Solvent: Chloroform Sample dissolution conditions: 60 ° C, 2 hours Temperature: 40 ° C
Measurement concentration: 50 mg / 50 mL
Injection volume: 100 μL
Column: Two trade names TSKgel GMHHR-H (manufactured by Tosoh Corporation) (measurement of glass transition temperature)
The glass transition of the thermoplastic polyurethane was measured using a differential scanning calorimeter (trade name DSC-7, manufactured by Perkin Elmer). A 5 mg sample is cut from the pellet and loaded into an aluminum pan. The bread was heated from −100 ° C. to 10 ° C./min and measured.

(Measurement of surface hardness)
According to JIS K7311, the JIS A hardness of the thermoplastic polyurethane at room temperature was measured.

(Measurement of Izod impact strength)
Izod impact strength at 23 ° C. was measured according to ASTM D256 using a notched Izod test piece obtained by injection molding. The impact was applied from the notch side. The injection molding was performed under the conditions of a nozzle temperature of 175 ° C., an injection time of 10 seconds, and a mold temperature of 60 ° C. using (trade name) IS100E manufactured by Toshiba Machine Plastics.

(Observation of phase structure)
The compression molded test piece was cut into ultrathin sections with an ultramicrotome, stained with ruthenic acid, and then observed with a transmission electron microscope (manufactured by JEOL Ltd., trade name JEM-2000FX). The compression molding was performed under the conditions of a heating temperature of 180 ° C., a pressure of 10 MPa, a heating time of 3 minutes, and a cooling temperature of 60 ° C. to obtain a test piece having a thickness of 1 mm.

(Measurement of heat resistance)
Vicat softening temperature was measured according to JIS K7206 using the injection test piece.

Example 1
Poly 3-hydroxybutyrate polymer (manufactured by PHB Industrial S / A, trade name Biocycle 1000) preliminarily dried in an oven at 80 ° C. for 4 hours and adipic acid-based thermoplastic polyurethane (manufactured by Nippon Milactolan) , Miractolan E190) 30% by weight to a bi-directional extruder with a circular die (Toyo Seiki Seisakusho, trade name Lab Blast Mill; resin temperature 178 ° C., rotation speed 100 rpm, using a strong kneading type screw) Then, melt extrusion mixing was performed, and the extruded strand was solidified in a hot bath set at 60 ° C., and pelletized with a strand cutter to obtain a pellet-shaped resin composition.

  Measure the crystallization temperature, crystal melting point, and weight average molecular weight of the chloroform-dissolved component of the resin composition obtained, measure the Izod impact strength and Vicat softening temperature using an injection test piece, and use a compression test piece. Were observed with a transmission electron microscope. The results are shown in Table 1.

  Table 2 shows the glass transition temperature and surface hardness of thermoplastic polyurethane alone.

  The obtained resin composition had high Vicat softening point and Izod impact strength, and was excellent in heat resistance and impact resistance.

Example 2
Other than blending 10 parts by weight of di-2-ethylhexyl phthalate (DOP) with a total amount of 100 parts by weight consisting of 70% by weight of poly-3-hydroxybutyrate polymer and 30% by weight of adipic acid-based thermoplastic polyurethane Obtained a pellet-shaped resin composition by the same method as in Example 1.

  Measure the crystallization temperature, crystal melting point, and weight average molecular weight of the chloroform-dissolved component of the resin composition obtained, measure the Izod impact strength and Vicat softening temperature using an injection test piece, and use a compression test piece. Were observed with a transmission electron microscope. The results are shown in Table 1.

  Table 2 shows the glass transition temperature and surface hardness of thermoplastic polyurethane alone.

  The obtained resin composition had high Vicat softening point and Izod impact strength, and was excellent in heat resistance and impact resistance.

Example 3
To 100 parts by weight of the total amount consisting of 70% by weight of poly-3-hydroxybutyrate polymer and 30% by weight of adipic acid-based thermoplastic polyurethane, talc (made by Nippon Talc Co., Ltd., trade name: MICRO ACE P-3) , Surface epoxy modification 1%) A pellet-shaped resin composition was obtained in the same manner as in Example 1 except that 10 parts by weight was blended.

  Measure the crystallization temperature, crystal melting point, and weight average molecular weight of the chloroform-dissolved component of the resin composition obtained, measure the Izod impact strength and Vicat softening temperature using an injection test piece, and use a compression test piece. Were observed with a transmission electron microscope. The results are shown in Table 1.

  Table 2 shows the glass transition temperature and surface hardness of thermoplastic polyurethane alone.

  The obtained resin composition had high Vicat softening point and Izod impact strength, and was excellent in heat resistance and impact resistance.

Example 4
In the same manner as in Example 1 except that a caprolactone-based thermoplastic polyurethane (Miraclan E585, manufactured by Nippon Milactolan Co., Ltd.) was used instead of the adipic acid-based thermoplastic polyurethane (Milaclane E190, manufactured by Nippon Milactolan Co., Ltd.). A resin composition was obtained.

  Measure the crystallization temperature, crystal melting point, and weight average molecular weight of the chloroform-dissolved component of the resin composition obtained, measure the Izod impact strength and Vicat softening temperature using an injection test piece, and use a compression test piece. Were observed with a transmission electron microscope. The results are shown in Table 1.

  Table 2 shows the glass transition temperature and surface hardness of thermoplastic polyurethane alone.

  The obtained resin composition had high Vicat softening point and Izod impact strength, and was excellent in heat resistance and impact resistance.

Example 5
Except for using an adipic acid-based thermoplastic polyurethane (manufactured by Nihon Milactolan E685) having a different diol component instead of an adipic acid-based thermoplastic polyurethane (Nilactolan E190, manufactured by Nihon Milactolan), the same as in Example 1 was used. A pellet-shaped resin composition was obtained by the method.

  Measure the crystallization temperature, crystal melting point, and weight average molecular weight of the chloroform-dissolved component of the resin composition obtained, measure the Izod impact strength and Vicat softening temperature using an injection test piece, and use a compression test piece. Were observed with a transmission electron microscope. The results are shown in Table 1.

  Table 2 shows the glass transition temperature and surface hardness of thermoplastic polyurethane alone.

  The obtained resin composition had high Vicat softening point and Izod impact strength, and was excellent in heat resistance and impact resistance.

Comparative Example 1
Pellets were obtained in the same manner as in Example 1 except that extrusion was performed only with a poly-3-hydroxybutyrate polymer (manufactured by PHB Industrial S / A, trade name Biocycle 1000).

  The crystallization temperature, crystal melting point, and weight average molecular weight of the chloroform-dissolved component of the obtained pellets were measured, and the Izod impact strength and Vicat softening temperature of the injection specimen were measured. Table 1 shows the results.

  The obtained resin had low Izod impact strength and was inferior in impact resistance.

Comparative Example 2
In the same manner as in Example 1 except that an ether-based thermoplastic polyurethane (Nippon Miractran E385, manufactured by Milactran E190) was used instead of the adipic acid-based thermoplastic polyurethane (Nippon Milactolan E190). A resin composition was obtained.

  The crystallization temperature, crystal melting point, and weight average molecular weight of the chloroform-dissolved component of the obtained resin composition were measured. Further, the Izod impact strength and the Vicat softening temperature were measured using the injection test piece, and further observed with the transmission electron microscope using the compression test piece. The results are shown in Table 1.

  Table 2 shows the glass transition temperature and surface hardness of thermoplastic polyurethane alone.

  The obtained resin composition had low Izod impact strength and was inferior in impact resistance.

Comparative Example 3
A mixture was obtained in the same manner as in Example 1 except that an adipic acid ester-based thermoplastic polyurethane (Nippon Miractran Emilactor E198) was used instead of the adipic acid-based thermoplastic polyurethane used in Example 1. .

  The crystallization temperature, crystal melting point, and weight average molecular weight of the chloroform-dissolved component of the obtained resin composition were measured. Further, the Izod impact strength and the Vicat softening temperature were measured using the injection test piece, and further observed with the transmission electron microscope using the compression test piece. The results are shown in Table 1.

  Table 2 shows the glass transition temperature and surface hardness of thermoplastic polyurethane alone.

  The obtained resin composition had low Izod impact strength and was inferior in impact resistance.

Comparative Example 4
A pellet-shaped resin composition was obtained in the same manner as in Example 1 except that the resin temperature immediately after discharge from the different-direction twin screw extruder was 178 ° C., except that the resin temperature was 250 ° C.

  The crystallization temperature, crystal melting point, and weight average molecular weight of the chloroform-dissolved component of the obtained resin composition were measured. Further, the Izod impact strength and the Vicat softening temperature were measured using the injection test piece, and further observed with the transmission electron microscope using the compression test piece. The results are shown in Table 1.

  Table 2 shows the glass transition temperature and surface hardness of thermoplastic polyurethane alone.

  The obtained resin composition had low Izod impact strength and was inferior in impact resistance.

Comparative Example 5
Example 1 except that 70% by weight of poly-3-hydroxybutyrate polymer and 30% by weight of thermoplastic polyurethane were used instead of 30% by weight of poly-3-hydroxybutyrate polymer and 70% by weight of thermoplastic polyurethane. A pellet-shaped resin composition was obtained by the same method as described above.

  The crystallization temperature, crystal melting point, and weight average molecular weight of the chloroform-dissolved component of the obtained resin composition were measured. Further, the Izod impact strength and the Vicat softening temperature were measured using the injection test piece, and further observed with the transmission electron microscope using the compression test piece. The results are shown in Table 1.

  Table 2 shows the glass transition temperature and surface hardness of thermoplastic polyurethane alone.

  The obtained resin composition had a low Vicat softening temperature of 68 ° C. and was inferior in heat resistance.

Claims (4)

It consists of 50 to 99% by weight of a poly-3-hydroxybutyrate polymer and 50 to 1% by weight of a thermoplastic polyurethane that satisfies the following requirements (a) and (b), and is shown in the following (c) and (d) A resin composition characterized by satisfying the requirements.
(A) The glass transition temperature when heated at a rate of temperature increase from −100 ° C. to 10 ° C./min with a differential scanning calorimeter is −30 to −50 ° C.
(B) JIS A surface hardness is 60 or more and 95 or less.
(C) Crystal in a differential scanning calorimeter when heated from room temperature to 180 ° C. at a heating rate of 80 ° C./min, held at 180 ° C. for 1 minute, and then cooled at a cooling rate of 10 ° C./min. The conversion temperature is 110 ° C. or higher and 170 ° C. or lower.
(D) The polystyrene-reduced weight average molecular weight (Mw) when the chloroform-dissolved component is measured by gel permeation chromatography is 100,000 or more and 3000000 or less.   2. The resin composition according to claim 1, wherein the soft segment is a thermoplastic polyurethane which is an adipic acid ester.   3. The phthalic acid plasticizer is further contained in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the total amount of the poly-3-hydroxybutyrate polymer and the thermoplastic polyurethane. The resin composition in any one of. When an ultrathin section of a compression molded specimen is observed with a transmission electron microscope, a sea-island structure is formed in which a poly-3-hydroxybutyrate polymer is a continuous phase and a thermoplastic polyurethane is a dispersed phase, and The resin composition according to claim 1, wherein an average particle size of the dispersed phase is 0.1 to 3 μm.