JP4543211B2 - Biodegradable resin composition and molded product thereof - Google Patents

Description

  The present invention relates to a resin composition excellent in biodegradability, which contains an L-lactic acid polymer or copolymer as a resin component, and a molded product thereof.

In recent years, as the trend toward green chemistry progresses, polylactic acid, polyhydroxybutyric acid, and the like, which are made from renewable resources such as starch, sugar, glucose, and vegetable oil, have attracted attention.
However, it is known that polylactic acid has a problem that its biodegradability in the environment is extremely low compared to biodegradable plastics such as polyhydroxybutyric acid, polycaprolactone, and polybutylene succinate (Non-Patent Documents 1 to 3). 3).

"Applied and Environmental Microbiology (Appl. Environ. Microbiol.)", Vol. 63, No. 4, p. 1637-1640 (1997) "World Journal of Microbiology and Biotechnology (WorldJ. Microbiol. Biotechnol.)," Volume 14, p. 133-138 (1998) “Applied and Environmental Microbiology (Appl. Environ. Microbiol.)”, Vol. 64, p. 5008-5011 (1998)

  An object of the present invention is to provide a polylactic acid-based or lactic acid copolymer-based resin composition that is excellent in biodegradability and easy to handle under such circumstances, and a molded product thereof.

  As a result of intensive research to solve the above problems, the present inventors have found that a resin composition containing a specific enzyme in a polymer or copolymer of L-lactic acid contributes to the achievement of the problems. The present invention has been made.

That is, according to the present invention, the following inventions are provided.
(1) (A) Mainly a polymer or copolymer of L-lactic acid, and selected from (B) proteinase K, subtilisin, α-chymotrypsin, and bean shimeji, fig or passion fruit powder or extract. A biodegradable resin composition comprising at least one enzyme, powder or extract.
(2) The biodegradable resin composition according to (1), wherein the ratio of the component (B) is in the range of 0.01 to 10% by mass with respect to the component (A).
(3) The biodegradable resin composition according to (1) or (2), wherein the component (A) has a number average molecular weight of 5,000 to 2,000,000.
(4) The biodegradable resin composition according to any one of (1) to (3), further containing a crystal nucleating agent.
(5) A molded product of the biodegradable resin composition according to any one of (1) to (4).

In the biodegradable resin composition of the present invention, a polymer of L-lactic acid, that is, a copolymer of poly L-lactic acid or L-lactic acid is used as the resin of component (A).
As a copolymer of L-lactic acid, L-lactic acid or L-lactide is used as one comonomer, and D-lactic acid, DL-lactide, D-lactide, 2-hydroxyisobutyric acid, 4-hydroxy is used as the other comonomer. Isobutyric acid, 10-hydroxydecanoic acid, 12-hydroxydodecanoic acid, 12-hydroxystearic acid, 16-hydroxyhexadecanoic acid, 10,16-dihydroxyhexadecanoic acid, 9,16-dihydroxyhexadecanoic acid, 18-hydroxyoctadecanoic acid, 20 -Hydroxyeicosanoic acid, 22-hydroxydocosanoic acid, 9,10,18-trihydroxyoctadecanoic acid, glycolide, β-propiolactone, γ-butyrolactone, β-butyrolactone, γ-methyl-γ-butyrolactone, γ- Ethyl-γ-butyrolactone, δ-valerolac T-, γ-valerolactone, ε-caprolactone, γ-caprolactone, 15-pentadecalactone, γ-butyrolactam, δ-valerolactam, ε-caprolactam, ω-laurolactam, hexamethylene adipamide, tetramethylene sebacamide , Hexamethylene sebacamide, glycine cyclic dimer, alanine cyclic dimer, ethylene oxide, propylene oxide and the like are preferably used. These other comonomers may be used alone or in combination of two or more.
The copolymer is preferably one in which one comonomer is increased in molar ratio relative to the other comonomer, and in particular, one in which the molar ratio of one comonomer to the other comonomer is higher than 60:40, more preferably 80:20. preferable.
The predetermined resin of the component (A) preferably has a molecular weight of 5,000 to 2,000,000, particularly 10,000 to 1,000,000.

In the biodegradable resin composition of the present invention, as the component (B), a specific enzyme, that is, proteinase K, subtilisin, α-chymotrypsin, a specific powder or extract, that is, a powder or extract of bamboo shoot, fig and passion fruit Used.
One of these enzymes, powders and extracts (hereinafter also referred to as enzymes) may be used, or two or more thereof may be used in combination.
The enzyme or the like is preferably a purified product, but it may be a crude product obtained by homogenizing plant secretions, animal organs, microorganism culture solution, or the like, or an industrial enzyme containing a stabilizer.

  About the ratio between each component in the biodegradable resin composition of this invention, (B) component is 0.01-10 mass% with respect to (A) component, Especially the ratio of the range of 0.01-5 mass% It is preferable to mix with.

The biodegradable resin composition of the present invention includes, as necessary, pigments, antioxidants, antistatic agents, matting agents, deterioration inhibitors, fluorescent whitening agents, UV stabilizers, slipping agents, wood powder, fillers, Additional components such as carbon black, thickener, chain extender, cross-linking agent, crystal nucleating agent, plasticizer, stabilizer, viscosity stabilizer, etc. can be included, among others crystal nucleating agents such as talc, It is preferable to use boron nitride, calcium carbonate, magnesium carbonate, titanium oxide or the like because crystallization at the time of thermoforming can be promoted and the heat resistance and mechanical strength of the molded product can be improved.
In addition, the biodegradable resin composition of the present invention includes starch and processed starch, pectin, chitin, chitosan, alginic acid or a salt thereof, xylose, cellulose, cellulose such as carboxymethylcellulose, and the like as long as the intended effect is not hindered. Derivatives, mitsumata, kokusaku, kana mugura, kuwa, figs, vegetable fibers such as cotton, kenaf, abaca, coconut shell, animal fibers such as silk and wool, glass fibers, carbon fibers, etc. Also good.

The biodegradable resin composition of the present invention can be prepared by heating and mixing the enzyme, powder or extract of the component (B) with the predetermined resin of the component (A).
In order to prevent a decrease in the activity of the enzyme, powder, or extract due to heat, the enzyme and the like should be sufficiently removed before mixing with the L-lactic acid polymer or copolymer thereof. is important. The removal of water from the enzyme or the like is effective for preventing hydrolysis of the L-lactic acid polymer or the copolymer thereof.
The heating and mixing method is a method of mixing the enzyme, powder or extract component with a Henschel mixer or kneader while heating the resin component, a method of melting and kneading the resin component with the enzyme, powder or extract component in an extruder, etc. Examples thereof include a blow molding method and a foam molding method. The heating temperature is usually 20 to 250 ° C., preferably 50 to 200 ° C., particularly 120 to 180 ° C.
When blending an L-lactic acid polymer or copolymer and an enzyme or the like with a Henschel mixer, the L-lactic acid polymer or copolymer and powder (starch, talc, etc.) are used to prevent a decrease in the activity of the enzyme or the like due to heating. , Calcium carbonate, zeolite, kaolin, wood powder, cellulose powder, etc.) are added to the Henschel mixer at the same time, heated and mixed at high speed, and the enzyme is added just before the torque of the Henschel mixer increases to produce a compound containing the enzyme, etc. It is also possible to do. The obtained compound can be used as it is, or further mixed with a polymer or copolymer of L-lactic acid to obtain a resin composition.
Furthermore, in order to prevent a decrease in activity due to heat of the enzyme, etc., the enzyme is blended with a resin having a low melting point such as polycaprolactone, polybutylene adipate or polyethylene adipate, and then the blend containing the enzyme and L-lactic acid are mixed. A biodegradable resin composition can also be produced by blending these polymers or their copolymers.
The biodegradable resin composition of the present invention can be molded into a sheet shape, a film shape, a fiber shape, a container shape by a method such as injection molding, extrusion molding, blow molding, press molding, calendar molding, etc. It can also be subjected to foam molding. When obtaining a molded product by foam molding, it is preferable to extrude a melt of a molding material containing a foaming agent from a high pressure zone to a low pressure zone. As the foaming agent, a thermal decomposition type foaming agent that releases a gas by heating, a hydrocarbon having low boiling point, carbon dioxide, halogen hydrocarbon, or the like can be used.

The biodegradation method of poly D-hydroxybutyric acid in the present invention is a method for degrading poly D-hydroxybutyric acid with lipase. Examples of lipases include alkaline lipase derived from Achromobacter and lipoprotein lipase derived from Alkaligenes. Lipase from Pseudomonas genus, lipase from Candida genus, lipase from Mucor genus, lipase from genus Rhizopus, lipase from genus Penicillium, lipase from genus Phycomyces, porcine pancreatic lipase, human pancreatic lipase, etc. Among them, mammalian lipase is preferable.
One type of these lipases may be used, or two or more types may be used in combination.
The poly-D-hydroxybutyric acid used in this biodegradation method is a homopolymer of D-hydroxybutyric acid or a D-hydroxybutyric acid and other comonomer in which the proportion of D-hydroxybutyric acid is 50% mol or more as a monomer component. It means a copolymer.

  The resin composition of the present invention has a remarkable effect of being extremely biodegradable and easy to handle, and can be formed into various shapes such as a film, a sheet, a plate, a foam, and a bottle. .

  The resin composition of the present invention is a packaging material such as a tray, foam tray, stretch film, shrink film, beverage bottle, toothbrush blister, film for house, tunnel film, multifilm, vegetation film, pot for seedling, seed string Agricultural and horticultural materials such as fertilizer and pesticide covering materials, vegetation nets, heavy bags, construction formwork, civil engineering sheets, lawn stakes and other civil engineering materials, fishing nets, laver nets, aquaculture nets, fishing lines, Fishing materials such as fishing bait bags, waterproof sheets such as disposable diapers and sanitary items, and packaging materials, garbage bags, plastic bags, draining nets, dishes, spoons, forks, and other lamination containers, binding tape, toothbrush and razor patterns, shampoo・ Rinse bottles, cosmetic bottles, pens, markers, daily necessities and miscellaneous goods, medical devices such as syringes, osteosynthesis, sutures, wound covers Medical materials of wood such as various filters such as air cleaning filter, other magnetic cards, labels, 剥型 paper, can be suitably used in the golf tee or the like, various applications.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Example 1
Poly L- lactic acid (manufactured by Shimadzu Corporation, Rakuti ♯1012, number average molecular weight Mn = 1.8 × 10 ⁵⁾ was added at the same time 50g corn starch 50g into a Henschel mixer, and mixed using a high-speed rotation, the torque of the Henschel mixer large Immediately before, 1 g of Proteinase K (manufactured by ICN) was added to produce an enzyme-containing compound. Further, the obtained compound was kneaded in a heated extruder and then pelletized. The obtained pellets were extruded at 190 ° C. to form a film having a thickness of 30 μm.

(Example 2)
A film was formed in the same manner as in Example 1 except that subtilisin (manufactured by Sigma) was used as an enzyme instead of proteinase K.

(Example 3)
A film was formed in the same manner as in Example 1 except that α-chymotrypsin (manufactured by Sigma) was used as the enzyme instead of proteinase K.

(Reference Example 1)
A film was formed in the same manner as in Example 1 except that pronase (manufactured by Boehringer Mannheim) was used as the enzyme instead of proteinase K.

(Reference Example 2)
A film was formed in the same manner as in Example 1 except that chymopapine (manufactured by Washington Biochemical Co., Ltd.) was used as the enzyme instead of proteinase K.

(Reference Example 3)
A film was formed in the same manner as in Example 1 except that papain (manufactured by Calbiochemnova Biochemical Co., Ltd.) was used as the enzyme instead of proteinase K.

(Reference Example 4)
A film was formed in the same manner as in Example 1 except that plasmin (manufactured by Sigma) was used as an enzyme instead of proteinase K.

(Reference Example 5)
A film was formed in the same manner as in Example 1 except that elastase (manufactured by Wako Pure Chemical Industries, Ltd.) was used as the enzyme instead of proteinase K.

(Reference Example 6)
A film was formed in the same manner as in Example 1 except that trypsin (manufactured by Sigma) was used as the enzyme instead of proteinase K.

Example 4
A film was formed in the same manner as in Example 1 except that lyophilized powder of Buna shimeji extract was used instead of proteinase K.

(Example 5)
A film was formed in the same manner as in Example 1 except that lyophilized powder of the extract was used instead of proteinase K.

(Example 6)
A film was formed in the same manner as in Example 1 except that lyophilized powder of a passion fruit extract was used in place of proteinase K.
These freeze-dried powders of the extracts of Examples 4 to 6 are hereinafter referred to as “extracted powder”.

(Example 7)
A film was formed in the same manner as in Example 1 except that a copolymer having a molar ratio of L-lactide and D-lactide of 90:10 was used instead of poly-L-lactic acid.

(Example 8)
A film was formed in the same manner as in Example 2 except that a copolymer having a molar ratio of L-lactide and D-lactide of 90:10 was used instead of poly-L-lactic acid.

Example 9
A film was formed in the same manner as in Example 3, except that a copolymer having a molar ratio of L-lactide and D-lactide of 90:10 was used instead of poly-L-lactic acid.

(Reference Example 7)
A film was formed in the same manner as in Reference Example 1 except that a copolymer having a molar ratio of L-lactide and D-lactide of 90:10 was used instead of poly-L-lactic acid.

(Reference Example 8)
A film was formed in the same manner as in Reference Example 2, except that a copolymer having a molar ratio of L-lactide and D-lactide of 90:10 was used instead of poly-L-lactic acid.

(Reference Example 9)
A film was formed in the same manner as in Reference Example 3 except that a copolymer having a molar ratio of L-lactide and D-lactide of 90:10 was used instead of poly-L-lactic acid.

(Reference Example 10)
A film was formed in the same manner as in Reference Example 4 except that a copolymer having a molar ratio of L-lactide and D-lactide of 90:10 was used instead of poly-L-lactic acid.

(Reference Example 11)
A film was formed in the same manner as in Reference Example 5 except that a copolymer having a molar ratio of L-lactide and D-lactide of 90:10 was used instead of poly-L-lactic acid.

(Reference Example 12)
A film was formed in the same manner as in Reference Example 6 except that a copolymer having a molar ratio of L-lactide and D-lactide of 90:10 was used instead of poly-L-lactic acid.

(Example 10)
A film was formed in the same manner as in Example 4 except that a copolymer having a molar ratio of L-lactide and D-lactide of 90:10 was used instead of poly-L-lactic acid.

(Example 11)
A film was formed in the same manner as in Example 5 except that a copolymer having a molar ratio of L-lactide and D-lactide of 90:10 was used instead of poly-L-lactic acid.

(Example 12)
A film was formed in the same manner as in Example 6 except that a copolymer having a molar ratio of L-lactide and D-lactide of 90:10 was used instead of poly-L-lactic acid.

(Reference Example 13)
A film was formed in the same manner as in Reference Example 6 except that a copolymer having a molar ratio of L-lactide and DL-β-butyrolactone of 90:10 was used instead of li-L-lactic acid.

(Reference Example 14)
A film was formed in the same manner as in Reference Example 6 except that a copolymer of L-lactide, DL-β-butyrolactone, and ε-caprolactone in a molar ratio of 90: 5: 5 was used instead of poly L-lactic acid.

(Reference Example 15)
A film was formed in the same manner as in Reference Example 6 except that a copolymer of L-lactide, DL-β-butyrolactone, and ε-caprolactam in a molar ratio of 90: 5: 5 was used instead of poly L-lactic acid.

(Reference Example 16)
A film was formed in the same manner as in Reference Example 6 except that a copolymer of L-lactide, DL-β-butyrolactone, and ethylene oxide having a molar ratio of 90: 5: 5 was used instead of poly L-lactic acid.

(Method for preparing lyophilized powder of Bunashimeji extract)
Homogenization was performed by adding 100 ml of 0.1M phosphate buffer (pH 7) to 50 g of bunashimeji. Further, filtration with gauze and high-speed centrifugation (10000 rpm) were performed. The obtained extract was freeze-dried to obtain a lysate powder of bunashimeji extract.

(Method for preparing fig extract lyophilized powder)
The extract liquid freeze-dried powder was obtained in the same manner as in the above-described method for preparing the freeze-dried powder of Bunashimeji, except that it was used instead of Bunashimeji.

(Preparation method of passion fruit extract freeze-dried powder)
A passion fruit extract lyophilized powder was obtained in the same manner as the above-mentioned method for preparing a lysed bunashimeji extract, except that passion fruit was used in place of bunashhimeji.

(Method for synthesizing copolymer having a molar ratio of L-lactide and D-lactide of 90:10)
In a nitrogen stream, 9 g of Pulac L-lactide, 1 g of Pulac D-lactide and 0.01 g of tin octylate Nacalai Tesque were added to a three-necked flask and heated at 130 ° C. for 1 hour. The obtained crude copolymer was dissolved in 100 ml of chloroform and precipitated in 500 ml of methanol. (Yield 9 g number average molecular weight 1.2 × 10 ⁴ )

(Method for synthesizing copolymer of L-lactide and DL-β-butyrolactone having a molar ratio of 90:10)
In a nitrogen stream, 9.26 g of Pulac L-lactide, 0.74 g of DL-β-butyrolactone manufactured by Tokyo Chemical Industry Co., Ltd. and 0.4 ml of triethylaluminum manufactured by Wako Pure Chemical Industries, Ltd. were added to a three-necked flask and stirred at 30 ° C. for 24 hours. . The obtained crude copolymer was dissolved in 100 ml of chloroform and precipitated in 500 ml of methanol. (Yield 3.6 g number average molecular weight 5.6 × 10 ³ )

(Method for synthesizing a copolymer of L-lactide, DL-β-butyrolactone and ε-caprolactone in a molar ratio of 90: 5: 5)
In a nitrogen stream, 4.2 g of DL-β-butyrolactone manufactured by Tokyo Chemical Industry Co., Ltd., 5.8 g of ε-caprolactone manufactured by Tokyo Chemical Industry Co., Ltd., and 0.01 g of tetraphenyl tin manufactured by Wako Pure Chemical Industries, Ltd. were added to a three-necked flask at 30 ° C. for 24 hours. Reacted. The obtained crude copolymer was dissolved in 100 ml of chloroform and precipitated in methanol. (Yield 5 g number average molecular weight 8.3 × 10 ³ ) 1 g of the obtained copolymer and 9 g poly L-lactide (Lacty # 1012, number average molecular weight Mn = 1.8 × 10 ⁵ ) manufactured by Shimadzu Corporation were added, and 200 Heat at 5 ° C. for 5 hours. The obtained crude ternary copolymer was dissolved in 100 ml of chloroform and precipitated in methanol. (Yield 7 g number average molecular weight 5.3 × 10 ³ )

(Method for synthesizing copolymer of L-lactide, DL-β-butyrolactone, and ε-caprolactam at a molar ratio of 90: 5: 5)
In a nitrogen stream, 4.2 g of DL-β-butyrolactone manufactured by Tokyo Chemical Industry Co., Ltd., 5.8 g of ε-caprolactam manufactured by Tokyo Chemical Industry Co., Ltd. and 0.01 g of tetraphenyl tin manufactured by Wako Pure Chemical Industries, Ltd. were added to the three-necked flask at 30 ° C. for 24 hours. Reacted. The obtained crude copolymer was dissolved in 100 ml of chloroform and precipitated in methanol. (Yield 4 g number average molecular weight 6.3 × 10 ³ ) 1 g of the obtained copolymer and 9 g of poly L-lactide (Lacty # 1012, number average molecular weight Mn = 1.8 × 10 ⁵ ) manufactured by Shimadzu were added, and 200 Heat at 5 ° C. for 5 hours. The obtained crude ternary copolymer was dissolved in 100 ml of chloroform and precipitated in methanol. (Yield 5 g number average molecular weight 4.2 × 10 ³ )

(Method for synthesizing a copolymer of L-lactide, ethylene oxide, and succinic acid in a molar ratio of 90: 5: 5)
In a nitrogen stream, 3.3 g of ethylene oxide manufactured by Tokyo Chemical Industry Co., Ltd., 6.7 g of succinic anhydride manufactured by Tokyo Chemical Industry Co., Ltd. and 0.01 g of diethoxymagnesium manufactured by Wako Pure Chemical Industries, Ltd. were added and reacted at 30 ° C. for 24 hours. The obtained crude copolymer was dissolved in 100 ml of chloroform and precipitated in methanol (yield 6 g, number average molecular weight 6.8 × 10 ³ ). 1 g of the obtained copolymer and 9 g of poly L-lactide manufactured by Shimadzu Corporation were added and heated at 200 ° C. for 5 hours. The obtained crude ternary copolymer was dissolved in 100 ml of chloroform and precipitated in methanol (yield 7 g number average molecular weight 5.8 × 10 ³ ).

(Test Examples 1 to 28) (Biodegradability test)
Using each of the films prepared in Examples 1-12 and Reference Examples 1-16 as samples, 10 mg of each was 4 ml of 0.1 M phosphate buffer (pH 7.0) and 1 ml of octyl glucoside solution (manufactured by Tokyo Chemical Industry Co., Ltd.). And stirred at 37 ° C. for 14 hours.
About the obtained process liquid, the water-soluble organic carbon concentration (ppm unit) was measured with the organic carbon measuring device (the Shimadzu Corporation make, product name: total organic carbon concentration measuring device TOC-5000A), and the result was represented. It is shown in the A column of 1.
For each sample prepared in the same manner as in each example except that the sample of each example and reference example, and the enzyme or extracted powder were heat-treated at 280 ° C. instead of the enzyme or extracted powder, The water-soluble organic carbon concentration (in ppm) was measured, and the result is shown as a blank in column B of Table 1.
The biodegradability of the samples of each Example and Reference Example is shown in the C column of Table 1 as the difference between the values in the A column and the B column.

  From this, it can be seen that the resin composition of the present invention is decomposed even in a state where an enzyme or an extract is contained.

(Comparative Test Example 1)
In place of the sample of Test Example 1, a 30 μm thick film consisting only of poly-L-lactic acid containing no enzyme was used as a comparative sample, and the sample was stirred in a buffer solution and measured in the same manner as in Test Example 1. However, water-soluble organic carbon was not detected in the treatment liquid.

(Test Examples 29 to 36)
10 ml of a 30 μm thick film consisting only of poly-L-lactic acid, 1 ml of various enzyme solutions (chymopapain, papain, plasmin, elastase, trypsin, bamboo shoot extract powder, fig extract powder and passion fruit extract powder), 0.1 M phosphate buffer The mixture was added to a mixed solution of 3 ml of a liquid (pH 7.0) and 1 ml of an octyl glucoside solution (manufactured by Tokyo Chemical Industry Co., Ltd.) and stirred at 37 ° C. for 14 hours.
About the obtained process liquid, the water-soluble organic carbon concentration (ppm unit) was measured with the organic carbon measuring device (the Shimadzu Corporation make, product name: total organic carbon concentration measuring device TOC-5000A), and the result was represented. It is shown in A column of 2.
The films were treated in the same manner except that these test examples and the enzyme or extract powder were heat-treated at 280 ° C. instead of the enzyme or extract powder, and the water-soluble organic carbon concentration (ppm unit) was measured. The results are shown as blanks in column B of Table 2.
The biodegradability of each test example is shown in the column C of Table 2 as the difference between the values in the columns A and B.

(Comparative Test Examples 2 to 4)
10 mg of a 30 μm-thick film consisting of poly-L-lactic acid alone, 1 ml of various enzyme solutions (proteinase K, subtilisin, α-chymotrypsin), 3 ml of 0.1 M phosphate buffer (pH 7.0), octyl glucoside solution (Tokyo Kasei Co., Ltd.) The product was added to 1 ml of the mixed solution and stirred at 37 ° C. for 14 hours.
About the obtained process liquid, the water-soluble organic carbon concentration (ppm unit) was measured with the organic carbon measuring device (the Shimadzu Corporation make, product name: total organic carbon concentration measuring device TOC-5000A), and the result was represented. It is shown in A column of 2.
The film was treated in the same manner except that these comparative test examples and the enzyme were heat-treated at 280 ° C. instead of the enzyme, and the water-soluble organic carbon concentration (in ppm) was measured. It is shown as a blank in column B of 2.
The biodegradability of each comparative test example is shown in the C column of Table 2 as the difference between the values in the A column and the B column.

(Test Examples 37 to 46)
Mitsubishi Gas Chemical Industries, Ltd. poly D- hydroxy cast film (30 [mu] m), 10 mg of various enzyme solution acid (number average molecular weight 2.1 × 10 ^5), Seikagaku Corporation Achromobacter derived from the genus alkaline lipase, raw Lipoprotein lipase derived from Alkagenes genus manufactured by Kagaku Kogyo, lipase derived from Pseudomonas genus manufactured by Amano (lipase AK), lipase derived from Candida genus manufactured by Sigma (type VII-S), derived from Mucor genus manufactured by Biocatalyst Lipase, lipase derived from Rhizopus genus manufactured by Sigma (type VI), lipase derived from Penicillium genus manufactured by Biocatalyst, lipase derived from Phycomyces genus manufactured by Wako Pure Chemical Industries, Ltd. (lipase PN), porcine pancreatic lipase manufactured by Sigma (type II) ), Sigma human pancreatic lipase (1 mg / ml) 1 ml, 0.1M The solution was added to 3 ml of a phosphate buffer (pH 7.0) and 1 ml of an octyl glucoside solution (manufactured by Tokyo Chemical Industry Co., Ltd.) and stirred at 37 ° C. for 14 hours.
About the obtained process liquid, the water-soluble organic carbon concentration (ppm unit) was measured with the organic carbon measuring device (the Shimadzu Corporation make, product name: total organic carbon concentration measuring device TOC-5000A), and the result was represented. It is shown in the A column of 3.
The film was treated in the same manner except that these test examples were used and the enzyme was heat-treated at 280 ° C. instead of the enzyme, and the water-soluble organic carbon concentration (in ppm) was measured. It is shown as a blank in the B column.
The biodegradability of each test example is shown in the column C of Table 3 as the difference between the values in the columns A and B.

  The resin composition of the present invention is extremely excellent in biodegradability, easy to handle, and can be formed into various shapes such as films, sheets, plates, foams, bottles, etc., so that packaging of trays, shrink films, various bottles, etc. Agricultural and horticultural materials such as materials, house films, tunnel films, and multi-films, civil engineering materials such as formwork and civil engineering sheets, fishing materials such as fishing nets, waterproof sheets such as disposable diapers and sanitary products, syringes, etc. Daily use and miscellaneous goods such as medical instruments, garbage bags, plastic bags, draining nets, dishes, etc., medical materials such as bone bonding materials, suture materials, wound dressings, filters, magnetic cards, labels, release paper, etc. Can be suitably used.

Claims (5)

  (A) L-lactic acid polymer or copolymer mainly, (B) at least one selected from proteinase K, subtilisin, α-chymotrypsin, and bean mushroom, fig or passion fruit powder or extract A biodegradable resin composition comprising a seed enzyme, powder or extract.   The biodegradable resin composition according to claim 1, wherein the ratio of the component (B) to the component (A) is in the range of 0.01 to 10% by mass.   The biodegradable resin composition according to claim 1 or 2, wherein the component (A) has a number average molecular weight of 5,000 to 2,000,000.   Furthermore, the biodegradable resin composition in any one of Claims 1-3 containing a crystal nucleating agent.   A molded product of the biodegradable resin composition according to any one of claims 1 to 4.