Biodegradable resin composition

Abstract

A biodegradable resin composition containing a biodegradable resin (A), a powdery substance (B) derived from animals and plants, and a component (C), the biodegradable resin (A) is at least one selected from the group consisting of thermoplastic starch, poly (butylene adipate / terephthalate), polylactic acid, poly (butylene succinate), poly (butylene adipate / succinate), polycaprolactone, and polyhydroxyalkanoic acid. The component (C) is at least one component selected from the group consisting of a plasticizer and a compound (X) containing at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group.

Description

Technical Field

[0001] The present disclosure relates to a biodegradable resin composition, and in particular to a biodegradable resin composition having high biodegradability in the ocean. Background Art

[0002] Biodegradable resins have different biodegradation rates, and their biodegradability may be very low in environments with few microorganisms such as the ocean.

[0003] As a method for improving the biodegradability of a biodegradable resin in such an environment, there is known a method of mixing a compound that dissolves in the surrounding environment such as the ocean with the biodegradable resin.

[0004] For example, Patent Document 1 discloses a technology for providing a method for producing a biodegradable plastic molded product containing plant food residues, wherein the cost is reduced and moldability is excellent by providing a step of adding a dry powder of plant food residues having an average particle size of less than a specific value.

[0005] Patent Document 2 discloses a technology for providing a biodegradable resin composition composed of a biodegradable resin and a dry powder of a food-derived protein, wherein by setting the contents of these components to a specific range, the biodegradable resin composition is rapidly biodegraded and assimilated when exposed to a composting environment.

[0006] Patent document 3 discloses a technology for providing a seedling raising pot having a layer composed of a composition containing a biodegradable resin, wherein, by containing a biodegradation accelerator in the biodegradable resin composition, biodegradation is suppressed during seedling raising and there is no peeling between the layers constituting the pot, and once buried in the soil together with the pot, biodegradation is quickly and completely carried out.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application No. 2002-371187

[0010] Patent Document 2: Japanese Patent Application Publication No. 2004-2687

[0011] Patent Document 3: Japanese Patent Application Publication No. 2004-2683 Summary of the invention

[0012] Problems to be solved by the invention

[0013] As disclosed in Patent Documents 1 to 3, the following developments have been made in the past: by adding specific components to biodegradable resin compositions, the biodegradability in marine environments, etc. has been improved. Through these developments, the biodegradability has been improved, but the degree of improvement is not sufficient, and further improvement is expected.

[0014] Furthermore, when a specific component is added to a biodegradable resin composition, the appearance of the composition and its molded article may be deteriorated due to the generation of bubbles or the like, and improvement of this problem is also desired.

[0015] Therefore, the technical problem of the present disclosure is to provide a biodegradable resin composition, which can produce a molded product with excellent appearance and biodegradability in the ocean. In addition, the technical problem of the present disclosure is to provide a molded product of the composition, a method for producing the composition, the use of a specific substance of the composition for improving marine biodegradability, and a method for improving marine biodegradability of the composition.

[0016] Solutions for solving problems

[0017] The present inventors have conducted intensive studies and, as a result, have found that the above-mentioned technical problems can be solved by including specific components in a biodegradable resin composition, thereby completing the present disclosure.

[0018] [1] A biodegradable resin composition comprising: a biodegradable resin (A), a powdered substance (B) derived from animals or plants, and a component (C), wherein the biodegradable resin (A) is at least one selected from the group consisting of thermoplastic starch, polybutylene adipate terephthalate, polylactic acid, polybutylene succinate, polybutylene succinate adipate, polycaprolactone and polyhydroxyalkanoic acid, and the component (C) is at least one selected from the group consisting of a compound (X) and a plasticizer, wherein the compound (X) is a compound containing at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group.

[0019] [2] The biodegradable resin composition according to [1], wherein the powdery substance (B) derived from animals or plants is at least one selected from the group consisting of a substance derived from soybean, wheat bran, defatted bran and rice husk.

[0020] [3] The biodegradable resin composition according to [2], wherein the soybean-derived substance is at least one selected from the group consisting of soybean meal, soybean hulls, soybean fiber, bean curd okara, bean curd okara fiber, and soy sauce meal.

[0021] [4] The biodegradable resin composition according to [3], wherein the powdery substance (B) derived from animals or plants is at least one selected from the group consisting of soybean meal, wheat bran, bean curd dregs and rice husks.

[0022] [5] The biodegradable resin composition according to any one of [1] to [4], wherein the biodegradable resin (A) is at least one selected from the group consisting of thermoplastic starch and polybutylene adipate terephthalate.

[0023] [6] The biodegradable resin composition according to any one of [1] to [5], wherein the content of the biodegradable resin (A) is 50% by weight or more.

[0024] [7] The biodegradable resin composition according to any one of [1] to [6], wherein the content of the powdery substance (B) derived from animals or plants is 5% by weight or more and 25% by weight or less.

[0025] [8] The biodegradable resin composition according to any one of [1] to [7], wherein the content of the component (C) is 0.05% by weight or more and 25% by weight or less.

[0026] [9] A molded article, wherein the molded article is a molded article of the biodegradable resin composition according to any one of [1] to [8].

[0027]

[10] The molded article according to [9], wherein the molded article is in a film form.

[0028]

[11] The molded article according to [9] or

[10] , wherein the molded article is used for a product that comes into contact with seawater.

[0029]

[12] A use of a molded article, wherein the molded article is the molded article as described in

[11] , and the molded article is used for a product that comes into contact with seawater.

[0030]

[13] A method for producing a biodegradable resin composition, comprising the step of mixing a biodegradable resin (A), a powdered substance (B) derived from animals or plants, and a component (C), wherein the biodegradable resin (A) is at least one selected from the group consisting of thermoplastic starch, polybutylene adipate terephthalate, polylactic acid, polybutylene succinate, polybutylene succinate adipate and polycaprolactone, and the component (C) is at least one selected from the group consisting of a compound (X) and a plasticizer, wherein the compound (X) is a compound containing at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group.

[0031]

[14] Use of a powdered substance derived from animals or plants, wherein the substance is used to prepare a biodegradable resin composition, the biodegradable resin composition containing at least one selected from the group consisting of polybutylene adipate terephthalate, polylactic acid, polybutylene succinate, polybutylene succinate adipate and polycaprolactone as a biodegradable resin, and the biodegradable resin composition also contains at least one component selected from the group consisting of a plasticizer and a compound containing at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group.

[0032]

[15] A method for improving the marine biodegradability of a molded article of a biodegradable resin composition, wherein the marine biodegradability of the resulting molded article of the biodegradable resin composition is improved by mixing the following substances: as a biodegradable resin, at least one selected from the group consisting of polybutylene adipate terephthalate, polylactic acid, polybutylene succinate, polybutylene succinate adipate and polycaprolactone; a powdery substance derived from animals or plants; and at least one component selected from the group consisting of a plasticizer and a compound, the compound containing at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group.

[0033] Effects of the Invention

[0034] According to the present disclosure, a biodegradable resin composition capable of producing a molded article having excellent appearance and biodegradability in the ocean can be provided. In addition, a molded article of the composition, a method for producing the composition, use of the composition as a specific substance for improving the marine biodegradability, and a method for improving the marine biodegradability of the composition can be provided. DETAILED DESCRIPTION

[0035] The following describes the embodiments of the present disclosure in detail. Each configuration and combination thereof in each embodiment is an example, and addition, omission, substitution and other changes of the configuration may be appropriately made without departing from the scope of the present disclosure. The present disclosure is not limited by the embodiments, but only by the scope of the technical solution.

[0036] In addition, in this disclosure, "high biodegradability in the ocean" means excellent biodegradability in the ocean or in a state of being in contact with seawater for a certain period of time or more.

[0037] Unless otherwise specified, the description "XX or more and YY or less" or "XX to YY" indicating a numerical range means a numerical range including the lower limit and the upper limit as endpoints. When the numerical range is described in stages, the upper and lower limits of each numerical range can be arbitrarily combined.

[0038] Furthermore, in the present disclosure, the expression “A or B” may be interpreted as “at least one selected from the group consisting of A and B”.

[0039] Furthermore, in the present disclosure, “plurality” means “two or more”.

[0040] <Biodegradable resin composition>

[0041] A biodegradable resin composition (also simply referred to as "biodegradable resin composition" or "composition") as one embodiment of the present disclosure contains a biodegradable resin (A), a powdered substance (B) derived from animals and plants, and a component (C), wherein the biodegradable resin (A) is at least one selected from the group consisting of thermoplastic starch, polybutylene adipate terephthalate (PBAT: Polybutylene adipate terephthalate), polylactic acid, polybutylene succinate (PBS: Polybutylene succinate), polybutylene succinate adipate (PBSA: Polybutylene succinateadipate), polycaprolactone and polyhydroxyalkanoic acid, and the component (C) is at least one selected from the group consisting of a compound (X) and a plasticizer, and the compound (X) is a compound containing at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group.

[0042] According to the studies conducted by the present inventors, it has been found that when a powdered substance derived from animals or plants is melt-kneaded into a conventional biodegradable resin composition, the appearance of a molded article of the composition deteriorates.

[0043] On the other hand, the present inventors have found that by including component (C) together with a specific biodegradable resin and a powdered substance derived from animals and plants in the biodegradable resin composition of the above-mentioned embodiment, it is possible to maintain high biodegradability in the ocean and make the appearance of the composition or its molded product good.

[0044] [Biodegradable resin (A)]

[0045] The kind of biodegradable resin (A) is just selected from at least one of the group consisting of thermoplastic starch, polybutylene adipate terephthalate, polylactic acid, polybutylene succinate, polybutylene succinate adipate, polycaprolactone and polyhydroxyalkanoic acid, and there is no particular restriction. From the viewpoint that the appearance of the molded article of the composition can be made good, it is preferably selected from at least one of the group consisting of thermoplastic starch, polybutylene adipate terephthalate, polylactic acid, polybutylene succinate and polybutylene succinate adipate, more preferably at least one of the group consisting of thermoplastic starch and polybutylene adipate terephthalate, and thermoplastic starch and polybutylene adipate terephthalate can also be used together. These biodegradable resins (A) can be used alone or in combination of two or more and in ratio. In addition, these biodegradable resins (A) can use the biodegradable resin manufactured according to a known manufacture method, or commercially available products can be used.

[0046] The content of the biodegradable resin (A) in the biodegradable resin composition (the total content in the case of containing multiple) is not particularly limited, and in order to ensure the appropriate strength of the molded product of the biodegradable resin composition, it is preferably 50% by weight or more. It should be noted that even in the biodegradable resin composition of the present invention, in the case of a biodegradable resin having a tendency to have poor biodegradability in the ocean at a high content of more than 50% by weight, by including a powdered substance (B) derived from animals and plants described later as a component that promotes marine decomposition, the sufficient biodegradability of the composition or its molded product in the ocean can be ensured. On the other hand, if the content of the powdered substance (B) derived from animals and plants in the biodegradable resin composition is too much, the biodegradation of the component is accelerated, and the biodegradation of the biodegradable resin is difficult to proceed smoothly. The content of the biodegradable resin (A) in the biodegradable resin composition is more preferably 60% by weight or more, more preferably 70% by weight or more, particularly preferably 75% by weight or more, and further particularly preferably 79% by weight or more. Moreover, the upper limit of the content of the biodegradable resin (A) is preferably 99% by weight or less, more preferably 97% by weight or less, further preferably 95% by weight or less, particularly preferably 93% by weight or less, and further particularly preferably 90% by weight or less, in consideration of the content of the powdered substance (B) and component (C) derived from animals and plants. The content of the biodegradable resin (A) is preferably, for example, 50 to 99% by weight, 60 to 97% by weight, 70 to 95% by weight, 75 to 93% by weight, and 79 to 90% by weight.

[0047] [Powdered substances derived from animals or plants (B)]

[0048] By including the powdered substance (B) derived from animals and plants in the biodegradable resin composition, it is possible to ensure good biodegradability of a molded article of the composition even in an environment such as the ocean where it comes into contact with seawater.

[0049] The present inventors presume that the reason for this is that by including the powdered substance (B) derived from animals and plants in the molded article of the resin composition, microorganisms contained in seawater can easily aggregate on the surface of the molded article, and the above-mentioned components and the biodegradable resin are efficiently assimilated by the microorganisms.

[0050] Thus, the biodegradable resin composition is preferably a marine biodegradable resin composition. The marine biodegradable resin composition refers to a biodegradable resin composition that is highly biodegradable in the ocean.

[0051] It should be noted that powdered substances derived from animals or plants can also be embodied as decomposition accelerators.

[0052] The powdery substance (B) derived from animals and plants of the present disclosure does not include the above-mentioned biodegradable resin (A).

[0053] The type of the powdered substance (B) derived from animals or plants is not particularly limited, but from the viewpoint of ensuring good biodegradability, it is preferably at least one selected from the group consisting of a substance derived from soybean, wheat bran, defatted bran, soy sauce meal, and rice husks. The substance derived from soybean is not particularly limited as long as it is derived from soybean, and specific examples thereof include at least one selected from the group consisting of soybean meal, soybean hulls, soybean fiber, bean curd dregs, bean curd dregs fiber, and soy sauce meal.

[0054] Among them, from the viewpoint of ensuring good biodegradability, at least one selected from the group consisting of soybean meal, wheat bran, bean curd residue and rice husk is preferred, and soybean meal is particularly preferred. The powdered substance (B) derived from animals and plants can be used alone, or two or more can be combined in any ratio. In addition, the powdered substance (B) derived from animals and plants can use a biodegradable resin produced according to a known production method, or a commercially available product.

[0055] Soybean meal is a meal obtained by squeezing out oil from soybeans. Soybean meal can be obtained as soybean meal by squeezing out oil from soybeans, or a commercial product can be used. Soybean meal is preferred because it is favored by microorganisms in seawater and has a good effect of promoting biodegradability.

[0056] Soybean hulls are the hulls of soybeans. Soybean hulls can be obtained by peeling soybeans that have not been subjected to any special treatment, or can be easily peeled off from soybeans that have been subjected to treatment such as heating, or commercially available products can be used.

[0057] Soybean fiber is a dietary fiber obtained from soybean meal. Soybean fiber can be obtained, for example, by steaming and extracting soybean meal to separate insoluble dietary fiber from water-soluble dietary fiber, or commercially available products can be used. That is, soybean fiber can be either insoluble dietary fiber or water-soluble dietary fiber.

[0058] Wheat bran is a byproduct obtained when wheat flour is produced from wheat. Specifically, wheat includes endosperm, germ, and husk (epidermis), and wheat bran refers to the remaining portion after removing the endosperm from wheat. Wheat bran can be obtained as a residue of wheat by removing the endosperm and germ from wheat, and a commercial product can also be used.

[0059] Tofu dregs are the residues of soybean milk squeezed out during the process of making tofu from soybeans. Tofu dregs can be obtained as tofu dregs by squeezing out soybean milk during the process of making tofu from soybeans, or commercial products can be used. It is preferred to use a dry powder obtained by evaporating water through a drying process.

[0060] Bean curd dregs fiber is a dietary fiber obtained from bean curd dregs. Bean curd dregs fiber can be obtained, for example, by steaming and extracting bean curd dregs to separate insoluble dietary fiber from water-soluble dietary fiber, or commercially available products can be used. That is, bean curd dregs fiber can be either insoluble dietary fiber or water-soluble dietary fiber.

[0061] Soy sauce meal is a by-product produced when moromi is squeezed in the production of soy sauce using soybeans as a raw material. The soybean curd okara fiber may be obtained as this by-product or a commercially available product may be used.

[0062] Defatted bran is obtained by removing fat from rice bran, which is the germ and the epidermis removed when brown rice is refined. Defatted bran may be obtained by removing fat from rice bran, or a commercial product may be used.

[0063] Rice husk refers to the outermost part of the husk of rice grains connected to the rice ear. Rice husk can be obtained as a byproduct of the process of threshing and husking rice and refining brown rice, or a commercial product can be used.

[0064] The powdery substance (B) derived from animals or plants is preferably pulverized according to the thickness of the molded article. For example, the powdery substance (B) derived from animals or plants is preferably pulverized.

[0065] The maximum particle size is preferably 200 μm or less, more preferably 100 μm or less, and further preferably 75 μm or less. The lower limit of the maximum particle size is not particularly limited, and may be 0.01 μm or 0.10 μm. Preferably, for example, 0.01 to 200 μm, 0.10 to 100 μm, and 0.10 to 75 μm can be cited.

[0066] In addition, the average particle size (also referred to as D50 (median diameter) in the present disclosure) is preferably 100 μm or less, more preferably 50 μm or less, and further preferably 30 μm or less. The lower limit of the median diameter is not particularly limited, and may be 0.01 μm or 0.10 μm. Preferably, for example, 0.01 to 100 μm, 0.10 to 50 μm, and 0.10 to 30 μm can be cited.

[0067] These ranges are particularly preferred when the molded product is in the form of a film. The maximum particle size and median diameter can be adjusted by changing the classification conditions such as the crushing time and screening. In addition, in the present disclosure, the median diameter refers to the central value of the volume basis measured by the laser diffraction / scattering particle size distribution measurement method.

[0068] The content of the powdered substance (B) derived from animals and plants in the biodegradable resin composition (the total content when it contains multiple substances) is not particularly limited. From the perspective of improving the cohesion of microorganisms for the resin composition or its molded products in an environment in contact with seawater such as in the ocean, and then improving its biodegradability, it is preferably more than 3% by weight, more preferably more than 5% by weight, and more preferably more than 7% by weight. On the other hand, the upper limit of the content of the powdered substance (B) derived from animals and plants, considering its content and the content of the above-mentioned biodegradable resin (A), is preferably less than 45% by weight, more preferably less than 25% by weight, and more preferably less than 20% by weight. Preferably, for example, 3 to 45% by weight, 5 to 25% by weight, and 7 to 20% by weight can be listed.

[0069] In the biodegradable resin composition, the ratio of the content of the biodegradable resin (A) to the powdered substance (B) derived from animals and plants is not particularly limited. In terms of weight ratio, when the content of the biodegradable resin (A) is set to 100, the content of the powdered substance (B) derived from animals and plants can be 0.5 to 40, preferably 1 to 35, and more preferably 5 to 30.

[0070] [Ingredient (C)]

[0071] The biodegradable resin composition comprises a component (C). The component (C) is at least one component selected from the group consisting of a compound (X) and a plasticizer, and the compound (X) is a compound containing at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group. The component (C) may be used alone or in any combination of two or more components and in a ratio. In addition, only one of the compound (X) and the plasticizer may be used, or both may be used.

[0072] Component (C) can improve the appearance of a molded article of the composition.

[0073] The component (C) of the present disclosure does not include the above-mentioned biodegradable resin (A) and the powdery substance (B) derived from animals or plants.

[0074] Furthermore, the plasticizer of the present disclosure is a substance excluding a compound including at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group.

[0075] The compound (X) is not particularly limited as long as it is a compound containing at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group.

[0076] The compound containing an epoxy group is not particularly limited as long as it is a compound having an epoxy group in one molecule, but is preferably a compound having two or more epoxy groups in one molecule. For example, sorbitol polyglycidyl ether, polypropylene glycol diglycidyl ether, glycerol polyglycidyl ether, glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, 1,6-hexanediol diglycidyl ether, pentaerythritol polyglycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, bisphenol A type epoxy compound, bisphenol F type epoxy compound, bisphenol S type epoxy compound, hydrogenated bisphenol type Epoxy compounds, 2,2'-diallylbisphenol A type epoxy compounds, propylene oxide addition bisphenol A type epoxy compounds, resorcinol type epoxy compounds, biphenyl type epoxy compounds, sulfur type epoxy compounds, phenol novolac type epoxy compounds, o-cresol novolac type epoxy compounds, diphenyl ether type epoxy compounds, glycidyl amine type epoxy compounds, alkyl polyol type epoxy compounds, rubber modified epoxy compounds or glycidyl ester compounds, etc.

[0077] Among them, sorbitan polyglycidyl ether is more preferably used.

[0078] The epoxy group-containing compound may be used alone or in any combination of two or more thereof in a certain ratio.

[0079] The compound containing a carbodiimide group has one or more carbodiimide groups in the molecule and can be synthesized by a generally known method, for example, by using an organic phosphorus compound or an organic metal compound as a catalyst, and synthesizing it by subjecting various polyisocyanates to a decarbonation condensation reaction in a solvent-free or inert solvent at a temperature of about 70° C. or above. There is no particular limitation as long as it is a compound having a carbodiimide group in one molecule, but preferably a compound having two or more carbodiimide groups in one molecule.

[0080] Examples of the monocarbodiimide having one carbodiimide group in one molecule include N,N'-diphenylcarbodiimide, N,N'-bis(2,6-diisopropylphenyl)carbodiimide, N,N'-bis(2,6-dimethylphenyl)carbodiimide, N,N'-bis(2,6-di-tert-butylphenyl)carbodiimide, N-tolyl-N'-phenylcarbodiimide, N,N'-di-p-nitrophenylcarbodiimide, N,N'-di-p-aminophenylcarbodiimide, N,N'-di-p-hydroxyphenylcarbodiimide, N-octadecyl-N'-phenylcarbodiimide, N-benzyl-N'-phenylcarbodiimide, N,N'-di-o-ethylphenylcarbodiimide, N,N N,N'-di-p-ethylphenylcarbodiimide, N,N'-di-o-isopropylphenylcarbodiimide, N,N'-di-p-isopropylphenylcarbodiimide, N,N'-di-o-isobutylphenylcarbodiimide, N,N'-di-p-isobutylphenylcarbodiimide, N,N'-di-(2,6-diethylphenyl)carbodiimide, N,N'-di-(2-ethyl-6-isopropylphenyl)carbodiimide, N,N'-di-(2-isobutyl-6-isopropylphenyl)carbodiimide, N,N'-di-(2,4,6-trimethylphenyl)carbodiimide, N,N'-di-(2,4,6-triisopropylphenyl)carbodiimide or N,N'-di-(2,4,6-triisobutylphenyl)carbodiimide, etc.

[0081] As the polycarbodiimide compound having two or more carbodiimide groups in one molecule, polycarbodiimide compounds produced by various methods can be used. Basically, polycarbodiimide compounds produced by conventional polycarbodiimide production methods [for example, U.S. Patent No. 2,941,956, Japanese Patent Publication No. 47-33279, J. Org. Chem. 28, 2069-2075 (1963), Chemical Review 1981, Vol. 81 No. 4, p619-621] can be used.

[0082] Examples of organic diisocyanates used as synthetic raw materials in the production of polycarbodiimide compounds include aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and mixtures thereof. Specifically, examples include 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,5-diisocyanate, and 1,5-diisocyanate. , 6-toluene diisocyanate, a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene diisocyanate, 2,6-diisopropylphenyl isocyanate, 1,3,5-triisopropylbenzene-2,4-diisocyanate, etc.

[0083] Among them, from the viewpoint that the degree of polymerization of the polycarbodiimide compound can be easily controlled, discoloration due to ultraviolet rays is not easy, and the appearance of the molded article of the composition is good, it is preferred to use aliphatic (including alicyclic) organic diisocyanates, and it is particularly preferred to use isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, tetramethylxylylene diisocyanate or a mixture of two of them.

[0084] In addition, in the case of the above-mentioned polycarbodiimide compound, the polymerization reaction can be stopped midway by cooling the polymerization reaction, etc., so as to control the polymerization degree to be appropriate. In this case, the terminal becomes an isocyanate group. In addition, there is also a method of blocking all or part of the residual terminal isocyanate groups using a compound that reacts with the terminal isocyanate group of the polycarbodiimide compound, etc., in order to control the polymerization degree to be appropriate. By controlling the polymerization degree, the compatibility with biodegradable plastics and the effects of improving storage stability can be improved, which is preferred in terms of quality improvement.

[0085] Examples of the monoisocyanate compound for capping the terminal of the polycarbodiimide compound to control the degree of polymerization include phenyl isocyanate, tolyl isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, and naphthyl isocyanate.

[0086] The end-capping agent used to cap the ends of the polycarbodiimide compound and control its polymerization degree is not limited to the above-mentioned monoisocyanate compounds, but also includes active hydrogen compounds that can react with isocyanate groups, such as: (i) methanol, ethanol, phenol, cyclohexanol, N-methylethanolamine, polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether that are aliphatic, aromatic or alicyclic compounds and have an -OH group; (ii) diethylamine and dicyclohexylamine with an -NH- group; (iii) butylamine and cyclohexylamine with an -NH2 group; (iv) succinic acid, benzoic acid, and cyclohexane acid with a -COOH group; (v) ethyl mercaptan, allyl mercaptan, and thiophenol with a -SH group; (vi) compounds with an epoxy group; (vii) acid anhydrides such as acetic anhydride, methyltetrahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

[0087] Among them, polyethylene glycol monomethyl ether as a compound having an -OH group, dicyclohexylamine as a compound having an -NH- group, or cyclohexylamine as a compound having an -NH2 group is preferred from the viewpoint of being able to achieve a good appearance and easy end-capping, and cyclohexylamine is more preferred.

[0088] The carbodiimide group-containing compound may be used alone or in combination of two or more in any combination and ratio.

[0089] Examples of the plasticizer include an adipate plasticizer, a phthalate plasticizer, and a sulfonate plasticizer.

[0090] Among them, it is preferable to use an adipate-based plasticizer from the viewpoint of improving the appearance of a molded article of the composition.

[0091] The carbodiimide group-containing compound may be used alone or in any combination of two or more thereof in a certain ratio.

[0092] The content of component (C) in the biodegradable resin composition (the total content in the case of containing multiple) is not particularly limited. From the viewpoint of being able to make the appearance of the molded article of the composition good, it is preferably 0.05% by weight or more, more preferably 0.1% by weight or more, more preferably 0.5% by weight or more, particularly preferably 1% by weight or more, more preferably 3% by weight or more, and most preferably 5% by weight or more. Moreover, the upper limit of the content of component (C), considering the content of the above-mentioned biodegradable resin (A) and the powdery substance (B) derived from animals and plants, is preferably 25% by weight or less, more preferably 20% by weight or less, more preferably 17% by weight or less, particularly preferably 15% by weight or less, further preferably 13% by weight or less, and most preferably 11% by weight or less. Preferably, for example, 0.05-25% by weight, 0.1-20% by weight, 0.5-17% by weight, 1-15% by weight, 3-13% by weight, and 5-11% by weight can be listed.

[0093] The content of compound (X) in the biodegradable resin composition (the total content when it contains multiple compounds) is not particularly limited. From the viewpoint of being able to make the appearance good, it is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, and more preferably 0.5% by weight or more. Moreover, the upper limit of the content of compound (X) is preferably 10% by weight or less, more preferably 5% by weight or less, and more preferably 3% by weight or less, taking into account the content of the above-mentioned biodegradable resin (A) and the powdered substance (B) derived from animals and plants. Preferably, for example, 0.1 to 10% by weight, 0.2 to 5% by weight, and 0.5 to 3% by weight can be cited.

[0094] The content of the plasticizer in the biodegradable resin composition (the total content when it contains multiple types) is not particularly limited. From the viewpoint of being able to make the appearance good, it is preferably 0.5% by weight or more, more preferably 1% by weight or more, and further preferably 5% by weight or more. Moreover, the upper limit of the content of the plasticizer, taking into account the content of the above-mentioned biodegradable resin (A) and the powdered substance (B) derived from animals and plants, is preferably 20% by weight or less, more preferably 15% by weight or less, and further preferably 13% by weight or less. Preferably, for example, 0.5 to 20% by weight, 1 to 15% by weight, and 5 to 13% by weight can be cited.

[0095] In the biodegradable resin composition, there is no particular restriction on the ratio of the content of the powdered substance (B) derived from animals and plants to the component (C). In terms of weight ratio, when the content of the powdered substance (B) derived from animals and plants is set to 100, the content of the component (C) can be 2 to 150, preferably 2 to 100, and more preferably 2 to 50.

[0096] [Other added ingredients]

[0097] The biodegradable resin composition disclosed herein may further contain other components within the range that does not hinder its function. In addition, other components include: pigments, fillers, leveling agents, surfactants, dispersants, ultraviolet absorbers, flame retardants, antioxidants, colorants or crosslinking agents.

[0098] Furthermore, the biodegradable resin composition may or may not contain a biodegradable resin other than the above-mentioned biodegradable resin (A).

[0099] <Method for producing biodegradable resin composition>

[0100] The method for producing the biodegradable resin composition of the present disclosure is not particularly limited, and a known method can be used.

[0101] An example of a method for producing a biodegradable resin is a method for producing a biodegradable resin composition, comprising the step of mixing a biodegradable resin (A), a powdered substance (B) derived from an animal or plant, and a component (C), wherein the biodegradable resin (A) is at least one selected from the group consisting of thermoplastic starch, polybutylene adipate terephthalate, polylactic acid, polybutylene succinate, polybutylene succinate adipate, and polycaprolactone, and the component (C) is at least one selected from the group consisting of a compound (X) and a plasticizer, and the compound (X) is a compound containing at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group.

[0102] The mixing method in the mixing step is not particularly limited, and examples thereof include a method in which a mixture of the components is melt-kneaded at a predetermined temperature, for example, about 120 to 250° C., using various single-screw or multi-screw extruders. The components may be kneaded together, or after kneading a portion of the components, the remaining components may be added and kneaded.

[0103] <Molding products>

[0104] The biodegradable resin composition of the present disclosure can be used to make molded articles. There is no limitation on the method for making the molded article, and the molded article can be made by heating the biodegradable resin composition prepared by the above method to a temperature above the softening point, molding and cooling it into a desired shape and size, and curing it. That is, the molded article of the biodegradable resin composition can be a molded article formed by curing the biodegradable resin composition.

[0105] The molded product is preferably in the form of a film. The film-shaped molded product refers to a molded product having a thickness of 2000 μm or less, for example. The thickness of the molded product may be, for example, 0.1 to 2000 μm or 1 to 2000 μm.

[0106] There is no particular restriction on the use of the above-mentioned molded article, for example, general-purpose products such as films, sheets, trays or garbage bags can be listed. Regarding these general-purpose products, even if they are not in contact with seawater during use, they may be discarded in the ocean after use. Regarding the film, a thickness of more than 1 μm and less than 100 μm can be listed, and regarding the sheet, a thickness of more than 100 μm and less than 2000 μm can be listed. Regarding the garbage bag, a thickness of more than 1 μm and less than 70 μm can be listed. In addition, as the use of the above-mentioned molded article, products in contact with seawater can also be listed. As products in contact with seawater, products used in aquaculture such as fishing gear including fishing lines and fishing nets can be listed. In the case of using the molded article obtained by using the biodegradable resin composition disclosed in the present invention for products in contact with seawater, the product will not decompose immediately when used. However, in the case of being lost in the ocean due to an accident, the product is decomposed in the ocean due to good marine biodegradability, so it is not easy to cause the residue of molded articles in the ocean, which has become increasingly serious in recent years.

[0107] The decomposition rate of the molded article obtained using the biodegradable resin composition of the present disclosure in the ocean is, for example, reduced by 10% by weight or more based on the original weight of a 50 μm thick film when immersed in seawater maintained at 30° C. for 1.5 months.

[0108] More specifically, examples include: a scheme in which soybean meal is used as the powdery substance (B) derived from animals and plants to reduce the content of the biodegradable resin composition by 25% by weight or more or 18% by weight or more; a scheme in which wheat bran is used to reduce the content of the biodegradable resin composition by 18% by weight or more; and a scheme in which to reduce the content of the biodegradable resin composition by 18% by weight or more when soybean meal is used as the powdery substance (B) derived from animals and plants.

[0109] Based on the above reasons, the molded articles of the biodegradable resin composition disclosed in the present invention are suitable for use in products that may accidentally flow into the ocean (e.g., the general-purpose products mentioned above), products that come into contact with seawater, and particularly products that are intended to come into contact with seawater (e.g., the products used in the aquaculture industry mentioned above).

[0110] In addition, based on the above description, it can be seen that according to the present disclosure, in order to improve the marine biodegradability of a molded product of a biodegradable resin composition, as a specific scheme, it is preferred to use a powdered substance derived from animals and plants for the preparation of the biodegradable resin composition, wherein the biodegradable resin composition contains at least one selected from the group consisting of polybutylene adipate terephthalate, polylactic acid, polybutylene succinate, polybutylene succinate adipate and polycaprolactone as a biodegradable resin, and also contains at least one component selected from the group consisting of a plasticizer and a compound, wherein the compound contains at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group.

[0111] In this case, the conditions such as the kind and content of each component can be applied in the same manner as the conditions such as the kind and content of each component described in the above-mentioned section "Biodegradable resin composition".

[0112] In addition, the present disclosure also includes a method for improving the marine biodegradability of a biodegradable resin composition, wherein the marine biodegradability of a molded article of the obtained biodegradable resin composition is improved by mixing the following substances: as a biodegradable resin, at least one selected from the group consisting of polybutylene adipate terephthalate, polylactic acid, polybutylene succinate, polybutylene succinate adipate and polycaprolactone; a powdered substance derived from animals and plants; and at least one component selected from the group consisting of a plasticizer and a compound, the compound containing at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group. That is, a method for improving the marine biodegradability of a molded article of the obtained biodegradable resin composition by mixing a powdered substance derived from animals and plants in a biodegradable resin composition, wherein the biodegradable resin composition, in addition to the above-mentioned biodegradable resin, further contains at least one component selected from the group consisting of a plasticizer and a compound, the compound containing at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group. According to the above method, a molded article having higher marine biodegradability than a molded article of a biodegradable resin composition containing no powdered substance derived from animals or plants can be produced.

[0113] In this case, the conditions such as the type and content of each component can be applied in the same manner as the conditions such as the type and content of each component described in the above-mentioned section "Biodegradable resin composition".

[0114] In addition, regarding the molding method of the resin composition obtained by the above method and the use of the molded article thereof, the contents described in the above-mentioned "molded article" can be used.

[0115] [Example]

[0116] Hereinafter, the present disclosure will be specifically described with reference to examples, but the present disclosure is not limited to the embodiments below.

[0117] <Raw materials>

[0118] In this example, the following materials were used as raw materials.

[0119] [Biodegradable resin]

[0120] Biodegradable resin: thermoplastic starch / polybutylene adipate terephthalate (manufactured by Novamont; EF05B).

[0121] [Powdered substances derived from animals and plants]

[0122] ·Soybean meal: soybean oil meal (manufactured by Showa Sangyo Co., Ltd.; N7-P1-K1).

[0123] · Tofu dregs: Tofu dregs powder (produced by TAKAHASHI; superfine tofu dregs powder).

[0124] ·Wheat bran: Wheat bran (manufactured by Showa Sangyo Co., Ltd.; bran).

[0125] · Rice husk: Rice husk (produced by TAKASHO Co., Ltd.).

[0126] ·Soybean hulls (produced by Shimizu Flour Milling Co., Ltd.).

[0127] ·Soybean fiber (manufactured by Food Bridge Japan Co., Ltd.).

[0128] · Bean curd dregs fiber (manufactured by Japan Garlic Co., Ltd.).

[0129] ·Soy sauce meal (produced by Mitsuru-Shoyu Co., Ltd.).

[0130] The powders were pulverized using a table pulverizer (Wonder Blender WB-1, manufactured by OSAKA CHEMICAL CO., LTD.), and the material that passed through a sieve with a mesh size of 75 μm was recovered, thereby obtaining a powdery material derived from animals and plants.

[0131] [Compound (X)]

[0132] Compound A containing carbodiimide group:

[0133] (synthesis)

[0134] In a flask equipped with a stirring motor, a nitrogen bubbling tube and a cooling tube, 576.4 g of 4,4'-dicyclohexylmethane diisocyanate and 2.9 g of a carbodiimide catalyst (3-methyl-1-phenyl-2-phosphole-1-oxide) were added, and the mixture was reacted at 175°C for 18 hours while bubbling nitrogen. After obtaining a terminal isocyanate compound having a polymerization degree of n=5, the mixture was cooled to 100°C, 74.9 g of cyclohexylamine was added thereto, and the mixture was stirred for 1 hour to obtain a carbodiimide group-containing compound A.

[0135] Carbodiimide group-containing compound B: Stabaxol I (manufactured by LANXESS CORPORATION).

[0136] Epoxy-containing compound A: DENACOL EX-614B (manufactured by Nagase ChemteX Co., Ltd., a water-soluble multifunctional aliphatic epoxy compound).

[0137] [Plasticizer]

[0138] Plasticizer: DAIFATTY-101 (manufactured by Daihachi Chemical Industry Co., Ltd.; adipate-based aliphatic plasticizer; dibasic acid ester).

[0139] <Production of biodegradable resin composition>

[0140] The raw materials were prepared at the ratios shown in Table 1, and kneaded (melt kneaded) for 6 minutes at 150° C. using a laboratory mixer to obtain a resin composition. It should be noted that a blank in the raw material column in Table 1 indicates that no addition was made. In addition, the values ​​of the raw materials in Table 1 are weight %.

[0141] <Marine biodegradability>

[0142] The above-mentioned resin composition obtained by melt kneading was flat-pressed at 150°C to produce a sheet with a thickness of about 50 μm, and a 20 mm square sheet was produced from the sheet. Each sheet was washed with ethanol, vacuum-dried and weighed, wrapped in a metal mesh and immersed in a water tank filled with seawater kept at 30°C. After 1.5 months, the metal mesh was picked up and the sheet was washed in the same way as before the test, dried and weighed, and the weight reduction ratio before and after the test was calculated, and evaluated according to the following evaluation criteria. The results are shown in Table 1.

[0143] [Evaluation criteria]

[0144] 3: The weight reduction ratio before and after the test is 25% by weight or more.

[0145] 2: The weight reduction ratio before and after the test is 18% by weight or more and less than 25% by weight.

[0146] 1: The weight reduction ratio before and after the test is less than 18% by weight.

[0147] <Appearance>

[0148] The above resin composition obtained by melt kneading was flat-pressed at 150°C to produce a sheet with a thickness of about 50 μm, and a 20 mm square sheet was produced from the sheet. The appearance of each sheet was observed using a microscope (device name: KEYENCE DIGITAL MICROSCOPE VHX-200) and evaluated according to the following evaluation criteria. The results are shown in Table 1.

[0149] [Evaluation criteria]

[0150] 4: No bubbles were observed.

[0151] 3: Very fine bubbles smaller than 20 μm were slightly observed.

[0152] 2: Bubbles of 90 μm or more were slightly observed.

[0153] 1: Bubbles of 90 μm or more were observed in large quantities.

[0154] [Table 1]

[0155]

[0156] From the evaluation results of the molded products of Examples 1 to 18, it was found that the molded products (sheets) obtained using the biodegradable resin composition according to the embodiment of the present disclosure were excellent in marine biodegradability and appearance.

[0157] On the other hand, the evaluation results of the molded product of Comparative Example 1 show that the composition not containing the powdered substance derived from animals and plants has poor marine biodegradability. This result suggests that by including the powdered substance derived from animals and plants in the composition, microorganisms in seawater are enriched in a large amount in the biodegradable resin in the molded product, and the biodegradability is improved.

[0158] Furthermore, the evaluation results of the molded products of Comparative Examples 2 to 5 show that the compositions not containing at least one component (component (C)) selected from the group consisting of a plasticizer and a compound containing at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group have poor appearance.

[0159] Industrial Applicability

[0160] According to the present disclosure, it is possible to provide a biodegradable resin composition or the like which has an excellent appearance and can be used to produce a molded article with high biodegradability in the ocean.

Claims

1. A biodegradable resin composition, wherein: contain: Biodegradable resin A, powdered substance B derived from animals and plants, and ingredient C, The biodegradable resin A is at least one selected from the group consisting of thermoplastic starch, polybutylene adipate terephthalate, polylactic acid, polybutylene succinate, polybutylene succinate adipate, polycaprolactone and polyhydroxyalkanoic acid, The component C is at least one component selected from the group consisting of compound X and a plasticizer, The compound X is a compound including at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group.

2. The biodegradable resin composition according to claim 1, wherein The powdery substance B derived from animals or plants is at least one selected from the group consisting of a substance derived from soybean, wheat bran, defatted bran, and rice husk.

3. The biodegradable resin composition according to claim 2, wherein The soybean-derived substance is at least one selected from the group consisting of soybean meal, soybean hulls, soybean fiber, bean curd dregs, bean curd dregs fiber, and soy sauce meal.

4. The biodegradable resin composition according to claim 3, wherein The powdered substance B derived from animals or plants is at least one selected from the group consisting of soybean meal, wheat bran, bean curd dregs, and rice husks.

5. The biodegradable resin composition according to any one of claims 1 to 4, wherein The biodegradable resin A is at least one selected from the group consisting of thermoplastic starch and polybutylene adipate terephthalate.

6. The biodegradable resin composition according to any one of claims 1 to 5, wherein The content of the biodegradable resin A is 50% by weight or more.

7. The biodegradable resin composition according to any one of claims 1 to 6, wherein The content of the powdered substance B derived from animals or plants is 5% by weight or more and 25% by weight or less.

8. The biodegradable resin composition according to any one of claims 1 to 7, wherein The content of the component C is 0.05% by weight or more and 25% by weight or less.

9. A molded article, wherein The molded article is a molded article of the biodegradable resin composition according to any one of claims 1 to 8.

10. The molded article according to claim 9, wherein The molded product is in the form of a film.

11. The molded article according to claim 9 or 10, wherein The molded product is used for products in contact with seawater.

12. Use of a molded article, wherein: The molded article is the molded article according to claim 11, and the molded article is used for a product that comes into contact with seawater.

13. A method for producing a biodegradable resin composition, wherein: include: A step of mixing the biodegradable resin A, the powdered substance B derived from animals and plants, and the component C. The biodegradable resin A is at least one selected from the group consisting of thermoplastic starch, polybutylene adipate terephthalate, polylactic acid, polybutylene succinate, polybutylene succinate adipate and polycaprolactone, The component C is at least one component selected from the group consisting of compound X and a plasticizer, The compound X is a compound including at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group.

14. Use of a powdered substance derived from animals or plants, wherein: The substance is used for preparing a biodegradable resin composition. The biodegradable resin composition contains at least one selected from the group consisting of polybutylene adipate terephthalate, polylactic acid, polybutylene succinate, polybutylene succinate adipate and polycaprolactone as a biodegradable resin, The biodegradable resin composition further contains at least one component selected from the group consisting of a plasticizer and a compound including at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group.

15. A method for improving the marine biodegradability of a molded article of a biodegradable resin composition, wherein: The marine biodegradability of the molded article of the biodegradable resin composition obtained is improved by mixing the following substances: As the biodegradable resin, at least one selected from the group consisting of polybutylene terephthalate, polylactic acid, polybutylene succinate, polybutylene succinate adipate and polycaprolactone; Powdered substances of animal or plant origin; as well as At least one component selected from the group consisting of a plasticizer and a compound including at least one functional group selected from the group consisting of an epoxy group and a carbodiimide group.

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