JP2010047732A - Resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve workability and working speed in working such as injection molding, film forming, blow molding, fiber spinning, extrusion foaming, and bead foaming by enhancing a rate of crystallization of a biodegradable polyester resin having a slow rate of crystallization. <P>SOLUTION: A molding is fabricated by using a resin composition including the biodegradable polyester and a peptide produced by coupling two molecules or more of one or more kinds of amino acids. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a resin composition containing a biodegradable polyester resin.

  In recent years, environmental problems caused by waste plastics have been highlighted, and biodegradable resins that are decomposed by the action of microorganisms after use are attracting attention as the realization of a recycling society on a global scale is eagerly desired. So far, polyester resins such as polymers or copolymers having lactic acid, polyhydric alcohol, polycarboxylic acid or hydroxycarboxylic acid as repeating units have been developed as biodegradable thermoplastic resins. However, these polyester resins have a drawback that the crystallization rate is slow. Among them, polyhydroxyalkanoate (hereinafter referred to as PHA), which is a polymer of aliphatic hydroxycarboxylic acid, has a particularly slow crystallization rate. It is known (Non-Patent Document 1). Since PHA has a low glass transition temperature, if the crystallization rate is slow, solidification from the molten state becomes slow during molding, making it difficult to process. It has a very serious problem in industrial production, which is bad.

Conventionally, addition of various crystal nucleating agents has been studied as a method for improving the crystallization rate of polyester. As a conventionally known crystal nucleating agent, for example, in Patent Document 1, as a crystal nucleating agent used for a biodegradable resin, a natural or synthetic silicate compound, titanium oxide, barium sulfate, tricalcium phosphate, calcium carbonate, phosphorus Examples of the silicate compound include kaolinite, halloysite, talc, smectite, vermulite, and mica. Examples of the PHA crystal nucleating agent include talc, atomized mica, boron nitride, and calcium carbonate. More effective organic phosphonic acids or organic phosphinic acids, or esters thereof, or acids or esters thereof. And metal compounds selected from the group consisting of oxides, hydroxides, and saturated or unsaturated carboxylates of metals of Group I to V of the periodic table (Patent Document 2), polyvinyl alcohol, chitin In addition, compounds composed of aromatic amino acids such as chitosan (Patent Document 3), tyrosine, and phenylalanine (Patent Document 4) are disclosed. Patent Document 5 discloses a compound containing a nitrogen-containing heteroaromatic nucleus as a crystal nucleating agent for thermoplastic polyester. Patent Document 6 discloses a metal salt of an amino acid as a crystal nucleating agent for a thermoplastic resin. However, the present situation is that a crystal nucleating agent having a substantially high effect has not yet been found.
JP 2005-336448 A JP-A-3-24151 JP 2007-77232 A US Pat. No. 5,516,565 Special Table 2007-517126 US Pat. No. 6,555,603 “Biopolymers” Volume 4, Polyesters III Applications and Commercial Products, WILEY-VCH, p67

  The object of the present invention is to improve the crystallization speed of these polyester resins having biodegradability that is slow to crystallize, and processability in processing such as injection molding, film molding, blow molding, fiber spinning, extrusion foaming, and bead foaming. To improve the processing speed.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have remarkably improved the crystallization speed of a polyester resin having biodegradability that is slow to crystallize by adding a specific compound as a crystal nucleating agent. As a result, the present invention has been completed.

That is, the first of the present invention is
(1) A resin composition containing a biodegradable polyester and a peptide formed by bonding two or more amino acids,
(2) The resin as described above, wherein the biodegradable polyester is a polymer obtained by polymerizing at least one unit selected from butylene succinate, caprolactone, hydroxyalkanoate, glycolic acid, and lactic acid. Composition,
(3) Polyester having biodegradability is 3-hydroxypropionate, 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyheptanoate, 3-hydroxyoctanoate, 3-hydroxynanoate 3-hydroxydecanoate, 3-hydroxydodecanoate, 3-hydroxydodecenoate, 3-hydroxytetradecanoate, 3-hydroxyhexadecanoate, 3-hydroxyoctadecanoate, 3-hydroxy At least one monomer unit selected from the group consisting of -4-pentenoate, 4-hydroxybutyrate, 4-hydroxyvalerate, 5-hydroxyvalerate and 6-hydroxyhexanoate, and 3-hydroxybutyrate unit The above description which is a copolymer obtained by polymerizing Resin composition,
(4) The biodegradable polyester is at least one monomer unit selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, and 3-hydroxybutyrate unit A resin composition as described above, which is a copolymer obtained by polymerizing
(5) The resin composition as described above, wherein the biodegradable polyester has a weight average molecular weight of 300,000 to 3,000,000.
(6) The resin composition as described above, wherein the composition ratio of 3-hydroxybutyrate is about 70 to 99 mol% in the copolymer;
(7) The resin composition as described above, wherein the peptide content is 0.05 to 10 parts by weight with respect to 100 parts by weight of the biodegradable polyester.
(8) The resin composition as described above, wherein the peptide contains glycine,
(9) The resin composition as described above, wherein the peptide is glycyl-L-leucine,
About.

  According to the present invention, the crystallization speed of a polyester resin having biodegradability that is slow to crystallize can be remarkably improved, and the polyester resin in processing such as injection molding, film molding, blow molding, fiber spinning, extrusion foaming, and bead foaming. Can improve the workability and processing speed.

  Hereinafter, the present invention will be described in more detail. The resin composition of the present invention contains a biodegradable polyester and a peptide formed by combining two or more amino acids.

  The biodegradable polyester resin of the present invention is not particularly limited as long as it is decomposed by microorganisms in nature. Examples include polybutylene succinate, polybutylene succinate adipate, polycaprolactone, polyhydroxyalkanoate (abbreviation: PHA), polyglycolic acid, polylactic acid, etc. Among them, the glass transition point is low and the crystallization rate is slow. In PHA, the resin composition of the present invention can particularly preferably improve processability and processing speed. The polyester resin may contain a copolymerizable component as long as the effects of the present invention are not impaired.

  Examples of the PHA include 3-hydroxypropionate, 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyheptanoate, 3-hydroxyoctanoate, 3-hydroxynonanoate, 3-hydroxydecano Ate, 3-hydroxydodecanoate, 3-hydroxydodecenoate, 3-hydroxytetradecanoate, 3-hydroxyhexadodecanoate, 3-hydroxyoctadodecanoate, 3-hydroxy-4-pentenoate, 4 A copolymer of at least one monomer selected from the group consisting of -hydroxybutyrate, 4-hydroxyvalerate, 5-hydroxyvalerate and 6-hydroxyhexanoate and 3-hydroxybutyrate, preferably 3-hydroxyvalerate At least one monomer unit selected from the group consisting of 3-hydroxyhexanoate and 3-hydroxy-octanoate, copolymers of 3-hydroxybutyrate units. The composition ratio of 3-hydroxybutyrate in these PHA is preferably 70 to 99 mol% in the copolymer. If it is less than 70 mol%, molding may be difficult, and if it exceeds 99 mol%, the resin is hard and brittle, which may cause quality problems.

  The molecular weight of the PHA is not particularly limited, but is preferably 300,000 to 3,000,000, more preferably 400,000 to 2,500,000, and more preferably 500,000 to 2,000,000 in terms of workability from the viewpoint of processability. If the weight average molecular weight of PHA is less than 300,000, mechanical properties such as strength may be insufficient, and if it exceeds 3 million, moldability may be inferior.

  The method for measuring the weight average molecular weight of PHA is not particularly limited, but as an example, chloroform is used as a mobile phase, a Waters GPC system is used as a system, and the column is used as a column of Shodex manufactured by Showa Denko K.K. By using K-804 (polystyrene gel), the molecular weight in terms of polystyrene can be obtained.

  In addition to the biodegradable polyester resin, the resin composition of the present invention can also contain natural polymers such as starch and cellulose. Moreover, thermoplastic resins other than the above can be blended as necessary.

  The resin composition of the present invention contains, as a crystal nucleating agent, a peptide formed by combining two or more amino acids. There are many natural or non-natural compounds in amino acids, but natural amino acids are preferred. The reason is that natural amino acids constituting proteins do not cause any problems such as environmental pollution when the present resin composition is decomposed by microorganisms in the soil or the like.

  Natural amino acids that constitute the protein include alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, 22 types of tyrosine, valine, selenocysteine, pyrrolysine. A peptide in which at least one or more selected from natural amino acids constituting these proteins are combined is, for example, a dipeptide such as glycylglycine or glycyl-L-leucine, glycylglycylglycine , Tripeptides such as L-leucylglycylglycine, and cyclic peptides such as cyclo-DL-alanylglycyl. In addition, a compound in which a part of an amino acid such as cystine is modified or decomposed, or a naturally occurring amino acid that does not constitute a protein, such as cyclotrisarcosyl containing sarcosine (N-methylglycine), is also included in the peptide of the present invention. include.

  Moreover, it is preferable that glycine is included as a peptide formed by combining at least one or more amino acids selected from amino acids constituting a protein, and glycyl-L-leucine is more preferable. This is because these peptides are decomposed together with the resin when the resin composition is decomposed by microorganisms in the soil or the like as described above, and thus problems such as environmental pollution do not occur at all.

  The effect as a crystal nucleating agent can be further enhanced by adding the peptide after reducing the particle size by pulverization or the like in advance. The particle size is preferably 500 μm or less, more preferably 100 μm or less. The particle size can be measured by a laser diffraction / scattering particle size distribution measuring device.

  As a method for reducing the particle size, conventionally known methods such as a collision plate type or powder collision type jet mill, bead mill, hammer mill, etc. can be used in addition to pulverization with a mortar. In addition, the crystal nucleating agent can be deposited on the surface of the polyester resin by mixing a solution of the crystal nucleating agent and the polyester resin, and then removing the solvent, without being pulverized.

  The content of the peptide in the resin composition in the present invention is usually 0 with respect to 100 parts by weight of the biodegradable polyester resin from the viewpoint of improving the crystallization speed and the balance of physical properties of the resulting resin composition. 0.05 parts by weight to 20 parts by weight or less, preferably 0.1 parts by weight to 10 parts by weight, and more preferably 0.1 parts by weight to 5 parts by weight.

  The resin composition of the present invention contains the above-mentioned peptide, which can improve the crystallization rate. However, other additives such as antioxidants, ultraviolet absorbers, colorants such as dyes and pigments, plasticizers, A lubricant, an inorganic filler, an antistatic agent, an antifungal agent, an antibacterial agent, a foaming agent, a flame retardant and the like can be blended and contained as necessary. Moreover, you may contain another crystal nucleating agent.

  A molded body can be produced by molding the resin composition obtained as described above. The molding method may be a conventionally known method, and examples thereof include injection molding, film molding, blow molding, fiber spinning, extrusion foaming, and bead foaming.

  The molded body can be used for various containers, packaging materials, agricultural and horticultural films, medical materials, and the like.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. Evaluation of crystallization was performed as follows.

<Evaluation method of crystallization>
Using DSC (DSC220 manufactured by SII Nano Technology Co., Ltd.), the temperature was raised from 25 ° C. to a temperature sufficiently higher than the melting point of the resin used at 10 ° C./min to melt the resin, and then 10 ° C./min. At 25 ° C. Thereafter, the temperature was raised again at 10 ° C./min, and evaluation was made based on the temperature and size of the peak showing crystallization (heat of crystallization) observed in this process. In addition, about the specific value of the heated temperature, it shows in each Example.

  Production Example 1 Production of poly-3-hydroxybutyrate-co-3-hydroxyhexanoate (PHBH) having a 3-hydroxyhexanoate (3HH) content of 12 mol%

<Preparation of plasmid vector for gene insertion>
As an insertion DNA, a DNA comprising a base sequence including a promoter of phaC of A. caviae and a ribosome binding site was prepared as follows. PCR was carried out using the genomic DNA of A. caviae as a template and the primers shown in SEQ ID NO: 1 and SEQ ID NO: 2. PCR was (1) 98 ° C. for 2 minutes, (2) 98 ° C. for 15 seconds, 60 ° C. for 30 seconds, and 68 ° C. for 20 seconds for 25 cycles, and the polymerase used was KOD-plus- (manufactured by TOYOBO). The DNA fragment obtained by PCR was terminally phosphorylated and digested with EcoRI. This DNA fragment was designated as PAc-5P + Eco.

  Next, the DNA insertion site is set immediately before the start codon of the bktB gene of the chromosomal DNA of the KNK-005AS strain described in JP 2008-029218 A [0038], and upstream of the start codon of the gene by the following procedure. A DNA consisting of the nucleotide sequence was prepared.

  Using the genomic DNA of the KNK-005 strain described in JP 2008-029218 A [0036] as a template DNA source, PCR was performed using the primers shown in SEQ ID NO: 3 and SEQ ID NO: 4 to initiate the bktB gene. DNA consisting of a base sequence upstream of the codon was obtained. PCR was (1) 98 ° C. for 2 minutes, (2) 98 ° C. for 15 seconds, 64 ° C. for 30 seconds, and 68 ° C. for 30 seconds for 25 cycles, and the polymerase used was KOD-plus-. The DNA fragment obtained by PCR was simultaneously digested with the restriction enzymes BamHI and EcoRI. This DNA fragment was designated as PbktB-Bam + Eco.

  PAc-5P + Eco and PbktB-Bam + Eco were ligated, and PCR was performed using the primers shown in SEQ ID NO: 3 and SEQ ID NO: 2 with the DNA produced in the ligation solution as the template DNA. PCR was (1) 98 ° C. for 2 minutes, 98 ° C. for 15 seconds, 60 ° C. for 30 seconds, and 68 ° C. for 50 seconds for 25 cycles, and the polymerase used was KOD-plus-. The DNA fragment obtained by PCR was terminally phosphorylated and digested with BamHI. This DNA fragment was designated as bPac-5P + Bam.

  Next, a DNA having a base sequence downstream from the initiation codon of the gene was prepared. PCR was performed using the genomic DNA of the KNK-005 strain as a template DNA source and the primers shown in SEQ ID NO: 5 and SEQ ID NO: 6 to obtain a DNA comprising a base sequence downstream from the start codon of the bktB gene. . PCR was (1) 98 ° C. for 2 minutes, (2) 98 ° C. for 15 seconds, 64 ° C. for 30 seconds, and 68 ° C. for 30 seconds for 25 cycles, and the polymerase used was KOD-plus-. The DNA fragment obtained by PCR was terminally phosphorylated and digested with ClaI. This DNA fragment was designated ORF-5P + Cla.

  bPac-5P + Bam and ORF-5P + Cla were ligated, and PCR was performed using the primers shown in SEQ ID NO: 3 and SEQ ID NO: 6 with the DNA generated in the ligation solution as the template DNA. For PCR, (1) 98 ° C. for 2 minutes, (2) 98 ° C. for 15 seconds, 60 ° C. for 30 seconds, and 68 ° C. for 1 minute 30 seconds were repeated 25 cycles, and the polymerase used was KOD-plus-. The DNA fragment obtained by PCR was co-digested with BamHI and ClaI. This DNA fragment was subcloned into a site digested with the same restriction enzyme of the vector pBluescript II KS (-) (manufactured by TOYOBO). The obtained vector was designated as bAO / pBlu. The base sequence was determined using a DNA sequencer 3130xl Genetic Analyzer manufactured by APPLIED BIOSSYSTEMS, and it was confirmed that it was the same as the base sequence of the template DNA.

  Subsequently, the pSACKm described in JP 2008-029218 A [0037] was treated with the restriction enzyme NotI to cut out a DNA fragment of about 5.7 kb containing the kanamycin resistance gene and the sacB gene. This was inserted into a site cleaved with the same enzyme of bAO / pBlu to prepare a plasmid bAO / pBlu / SacB-Km for gene disruption / insertion.

<Preparation of gene insertion strain Pac-bktB / AS strain>
Next, using the KNK-005AS strain as a parent strain, a strain in which a DNA comprising a nucleotide sequence including a phaC promoter and a ribosome binding site was inserted immediately before the start codon of the bktB gene using bAO / pBlu / SacB-Km was prepared. E. coli strain S17-1 (ATCC 47005) was transformed with the gene insertion plasmid bAO / pBlu / SacB-Km. The obtained transformant was mixed and cultured on KNK-005AS strain and Nutrient Agar medium (manufactured by Difco) to perform conjugation transfer. Simmons agar medium containing 250 mg / L kanamycin (sodium citrate 2 g / L, sodium chloride 5 g / L, magnesium sulfate heptahydrate 0.2 g / L, ammonium dihydrogen phosphate 1 g / L, dihydrogen phosphate 2 A strain that had grown on potassium 1 g / L, agar 15 g / L, pH 6.8) was selected to obtain a strain in which the plasmid was integrated on the chromosome of the KNK-005AS strain. This strain is cultured for 2 generations in Nutrient Broth medium (Difco), then diluted and applied to Nutrient Agar medium containing 15% sucrose, and the grown strain is selected to perform the second recombination. The resulting stock was acquired. Furthermore, a desired gene insertion strain was isolated by PCR analysis.

  This gene insertion strain was named Pac-bktB / AS strain, its nucleotide sequence was determined using a DNA sequencer 3130xl Genetic Analyzer, and DNA comprising a phaC promoter and a ribosome binding site immediately before the start codon of the bktB gene Was confirmed to be an inserted strain.

<Cloning of ccr gene and expression unit construction>
The ccr gene encoding an enzyme that converts crotonyl-CoA to butyryl-CoA, the precursor of 3HH monomer, was cloned from the chromosomal DNA of Streptomyces cinnamonensis strain Okami (DSM 1042). PCR was performed using the DNAs of SEQ ID NO: 7 and SEQ ID NO: 8 as primers. The conditions were (1) 98 ° C. for 2 minutes, (2) 94 ° C. for 10 seconds, 55 ° C. for 20 seconds and 68 ° C. for 90 seconds for 25 cycles, and the polymerase used was KOD-plus-. The fragment amplified by PCR was purified and then cleaved with restriction enzymes BamHI and AflII. Subcloning the EE32d13 fragment (J. Bacteriol., 179, 4821 (1997)) into the EcoRI site of the pUC19 vector, cutting this plasmid with BglII and AflII, and replacing the ccr gene with the BamHI and AflII fragments. The ccr expression unit was constructed by

<Cloning of phaC gene and preparation of expression unit>
A phaC expression unit containing SEQ ID NO: 11 was prepared as a SpeI fragment. PCR was carried out using HG :: PRe-N149S / D171G-T / pBlu described in JP-A-2007-228894 [0031] as a template and primers shown in SEQ ID NO: 9 and SEQ ID NO: 10. The conditions were (1) 98 ° C. for 2 minutes, (2) 94 ° C. for 10 seconds, 55 ° C. for 30 seconds and 68 ° C. for 2 minutes for 25 cycles, and the polymerase used was KOD-plus-. The fragment amplified by PCR was purified and then cleaved with the restriction enzyme SpeI to prepare an expression unit.
The expression vector pCUP2-631 was constructed as follows.

  As a plasmid vector for constructing an expression vector in C. necator, pCUP2 described in WO / 2007/049716 [0041] was used. First, the ccr gene expression unit constructed in Example 7 was excised by EcoRI treatment, and this fragment was ligated with pCUP2 cleaved with MunI. Next, the phaC expression unit prepared in Example 8 was prepared as a SpeI fragment and inserted into the SpeI site of pCUP2 containing the ccr gene expression unit to construct a pCUP2-631 vector.

<Production of transformant>
The introduction of the pCUP2-631 vector into various cells was carried out by electrical introduction as follows. The gene introduction apparatus used was a gene pulser manufactured by Biorad, and the cuvette used was a gap 0.2 cm manufactured by Biorad. 400 μl of competent cells and 20 μl of expression vector were injected into a cuvette and set in a pulse device, and an electric pulse was applied under the conditions of electrostatic capacity 25 μF, voltage 1.5 kV, and resistance value 800Ω. After the pulse, the bacterial solution in the cuvette was cultured with shaking on Nutrient Broth medium (manufactured by DIFCO) at 30 ° C. for 3 hours, and selected plate (NutrientAgar medium (manufactured by DIFCO), kanamycin 100 mg / L) at 30 ° C. The cultured transformants were cultured for a day to obtain transformed transformants.

<Culture of transformant>
The transformant prepared above was cultured. The composition of the pre-medium was 1% (w / v) Meat-extract, 1% (w / v) Bacto-Trypton, 0.2% (w / v) Yeast-extract, 0.9% (w / v) Na 2 HPO 4 Adjusted to pH 6.7 with 12H2O and 0.15% (w / v) KH2PO4.

  The composition of the polyester production medium is 1.1% (w / v) Na2HPO4 · 12H2O, 0.19% (w / v) KH2PO4, 0.6% (w / v) (NH4) 2SO4, 0.1% (w / v) MgSO4 · 7H2O, 0.5% (v / v) trace metal salt solution (1.6% (w / v) FeCl3 · 6H2O in 0.1N hydrochloric acid, 1% (w / v) CaCl2 · 2H2O, 0.02% (w / v) CoCl2 · 6H2O, 0.016% (w / v) CuSO4 · 5H2O, 0.012% (w / v) NiCl2 · 6H2O, 0.01% (w / v) CrCl3 · 6H2O was dissolved.). It was performed by fed-batch culture in which PKOO (Palm kernel olein, palm kernel oil olein fraction) was fed as a carbon source.

  Glycerol stock of each transformant was inoculated into the pre-culture medium and cultured for 20 hours, and 10% (v) was added to a 5 L jar fermenter (MD-500 manufactured by Maruhishi Bioengineer) containing 2.5 L of polyester production medium. / v) Inoculated. The operating conditions were a culture temperature of 28 ° C., a stirring speed of 420 rpm, an aeration rate of 0.6 vvm, and a pH controlled between 6.6 and 6.8. For control, 14% aqueous ammonia was used. Incubation was carried out for up to 65 hours. After incubation, the cells were collected by centrifugation, washed with methanol, and lyophilized to obtain PHBH.

  The 3HH composition analysis of the produced polyester was measured by gas chromatography as follows. To about 20 mg of dry PHBH, 2 ml of sulfuric acid-methanol mixture (15:85) and 2 ml of chloroform were added and sealed, and heated at 100 ° C. for 140 minutes to obtain methyl ester of PHBH decomposition product. After cooling, 1.5 g of sodium bicarbonate was added little by little to neutralize it, and the mixture was allowed to stand until generation of carbon dioxide gas ceased. After adding 4 ml of diisopropyl ether and mixing well, the mixture was centrifuged and the monomer unit composition of the PHBH degradation product in the supernatant was analyzed by capillary gas chromatography. The gas chromatograph used was Shimadzu GC-17A, and the capillary column used was GL Science's NEUTRA BOND-1 (column length 25 m, column inner diameter 0.25 mm, liquid film thickness 0.4 μm). He was used as the carrier gas, the column inlet pressure was 100 kPa, and 1 μl of the sample was injected. As temperature conditions, the temperature was raised from an initial temperature of 100 to 200 ° C. at a rate of 8 ° C./min, and further from 200 to 290 ° C. at a rate of 30 ° C./min. As a result of analysis under the above conditions, it was PHBH having a 3HH ratio of 12%.

Example 1
Crystallization was evaluated using a copolymer containing 3-hydroxybutanoate repeating units in the repeating units of 3-hydroxybutyrate (hereinafter, this copolymer is referred to as PHBH). PHBH was produced by the method shown in Production Example 1. The content of 3-hydroxyhexanoate repeating units in the copolymer was 12 mol%, and the Mw (weight average molecular weight) was about 660,000. I used something. In a PHBH methylene chloride solution (PHBH content 2.5% w / v), glycyl-L-leucine (special grade reagent manufactured by Wako Pure Chemical Industries) was ground in a mortar, and 2 parts by weight were added to 100 parts by weight of PHBH. After dispersing by applying ultrasonic waves, the film was cast on glass to produce a film. A part of this film was sampled, and the temperature was raised to 180 ° C. by DSC to evaluate crystallization. As a result, a crystallization peak was observed at 63 ° C. during the re-heating process. The heat of crystallization at that time was 31 J / g.

(Comparative Example 1)
Except that glycyl-L-leucine was not added to PHBH, the temperature was raised to 180 ° C. by DSC in the same manner as in Example 1, and no crystallization peak was observed in any process. .

(Comparative Example 2)
Instead of glycyl-L-leucine, L-(−)-phenylalanine (special grade reagent manufactured by Nacalai Tesque), which is a crystal nucleating agent described in US Pat. No. 6,555,603, is added in an amount of 2 parts by weight based on 100 parts by weight of PHBH. Except for the addition of a portion, when the temperature was raised to 180 ° C. by DSC and the crystallization was evaluated in the same manner as in Example 1, no crystallization peak was observed in any process.

Claims (9)

  A resin composition comprising a biodegradable polyester and a peptide formed by binding two or more amino acids.   2. The resin composition according to claim 1, wherein the biodegradable polyester is a polymer obtained by polymerizing at least one unit selected from butylene succinate, caprolactone, hydroxyalkanoate, glycolic acid, and lactic acid. object.   Polyesters having biodegradability are 3-hydroxypropionate, 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyheptanoate, 3-hydroxyoctanoate, 3-hydroxynanoate, 3- Hydroxydecanoate, 3-hydroxydodecanoate, 3-hydroxydodecenoate, 3-hydroxytetradecanoate, 3-hydroxyhexadecanoate, 3-hydroxyoctadecanoate, 3-hydroxy-4- Polymerizing at least one monomer unit selected from the group consisting of pentenoate, 4-hydroxybutyrate, 4-hydroxyvalerate, 5-hydroxyvalerate and 6-hydroxyhexanoate and 3-hydroxybutyrate unit; The copolymer according to claim 2, wherein the copolymer is Fat composition.   The biodegradable polyester polymerizes at least one monomer unit selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyhexanoate, and 3-hydroxyoctanoate and 3-hydroxybutyrate unit. The resin composition according to claim 3, which is a copolymer.   The resin composition according to claim 4, wherein the biodegradable polyester has a weight average molecular weight of 300,000 to 3,000,000.   The resin composition according to any one of claims 3 to 5, wherein the composition ratio of 3-hydroxybutyrate is about 70 to 99 mol% in the copolymer.   The resin composition according to any one of claims 1 to 6, wherein the peptide content is 0.05 to 10 parts by weight with respect to 100 parts by weight of the biodegradable polyester.   The resin composition according to any one of claims 1 to 7, wherein the peptide contains glycine.   The resin composition according to any one of claims 1 to 7, wherein the peptide is glycyl-L-leucine.