Biodegradable resin composition

Abstract

A biodegradable resin composition containing a biodegradable resin, the biodegradable resin composition containing one or more components selected from the group consisting of soybean-derived substances and wheat bran, and the biodegradable resin being a poly (butylene adipate / terephthalate).

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 methods for improving the biodegradability of biodegradable resins in the ocean, there are known methods of mixing a compound soluble in seawater with the biodegradable resin and a method of preliminarily containing biodegradable bacteria of the biodegradable resin in the biodegradable resin.

[0004] For example, Patent Document 1 discloses a biodegradable resin composition containing an aliphatic polyester-based biodegradable resin as a biodegradable resin and corn gluten meal.

[0005] Patent Document 2 discloses a biodegradable resin composition obtained by mixing a biodegradation accelerator such as defatted rice bran with a biodegradable resin such as polybutylene succinateadipate (PBSA) or polybutylene adipate terephthalate (PBAT).

[0006] Furthermore, Patent Document 3 discloses a biodegradable resin composition obtained by mixing powdered rice bran as a substance that accelerates the biodegradation rate with a polycaprolactone resin.

[0007] Furthermore, Patent Document 4 discloses a biodegradable resin composition obtained by mixing casein or the like with a biodegradable resin such as polybutylene succinate adipate and polybutylene adipate terephthalate.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2004-002687

[0011] Patent Document 2: Japanese Patent Application Publication No. 2021-091846

[0012] Patent Document 3: Japanese Patent Application Publication No. 2001-323177

[0013] Patent Document 4: International Publication No. 2021 / 241712 Summary of the invention

[0014] Problems to be solved by the invention

[0015] The present inventors have conducted intensive research and have found that the above-mentioned biodegradable resin compositions are not yet sufficiently biodegradable in the ocean. In addition, the present inventors have found that the performance of the above-mentioned biodegradability accelerators is not yet sufficient to improve the biodegradability of polybutylene adipate terephthalate among biodegradable resins, especially the biodegradability in the ocean.

[0016] Therefore, the technical problem of the present disclosure is to provide a biodegradable resin composition or the like which can produce a molded article having high biodegradability in the ocean even if it contains polybutylene adipate terephthalate as a biodegradable resin.

[0017] Solutions for solving problems

[0018] The present inventors have conducted intensive studies to solve the above-mentioned technical problems and, as a result, have found that the above-mentioned technical problems can be solved by mixing specific components into polybutylene adipate terephthalate as a biodegradable resin, thereby completing the present disclosure.

[0019] The present disclosure is as follows.

[0020] [1] A biodegradable resin composition comprising a biodegradable resin, wherein the biodegradable resin composition comprises one or more components selected from the group consisting of a soybean-derived substance and wheat bran, and the biodegradable resin is polybutylene adipate terephthalate.

[0021] [2] The biodegradable resin composition according to [1], 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.

[0022] [3] The biodegradable resin composition according to [1], wherein the biodegradable resin composition comprises one or more components selected from the group consisting of soybean meal, wheat bran and bean curd okara.

[0023] [4] The biodegradable resin composition according to any one of [1] to [3], wherein the content of the biodegradable resin is 50% by weight or more.

[0024] [5] The biodegradable resin composition according to any one of [1] to [4], wherein the content of the component is 5 to 25% by weight.

[0025] [6] A molded article, wherein the molded article is a molded article of the biodegradable resin composition according to any one of [1] to [5].

[0026] [7] The molded article according to [6], wherein the molded article is in a film form.

[0027] [8] The molded article according to [6] or [7], wherein the molded article is used for a product that comes into contact with seawater.

[0028] [9] Use of a molded article, wherein the molded article is the molded article according to [8], and the molded article is used for a product that comes into contact with seawater.

[0029]

[10] A method for producing a biodegradable resin composition, comprising the step of mixing at least one component selected from the group consisting of a soybean-derived substance and wheat bran with a biodegradable resin, wherein the biodegradable resin is polybutylene adipate terephthalate.

[0030]

[11] The method for producing a biodegradable resin composition according to

[10] , wherein the component is at least one component selected from the group consisting of soybean meal, wheat bran and bean curd okara.

[0031]

[12] Use of a component, wherein the component is at least one component selected from the group consisting of a substance derived from soybean and wheat bran, and the component is used for preparing a biodegradable resin composition containing at least polybutylene adipate terephthalate as a biodegradable resin.

[0032]

[13] The use of the component according to

[12] , wherein the component is at least one component selected from the group consisting of soybean meal, wheat bran and bean curd okara.

[0033]

[14] 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 is improved by mixing at least one component selected from the group consisting of a substance derived from soybeans and wheat bran with at least polybutylene adipate terephthalate as a biodegradable resin.

[0034]

[15] The method according to

[14] , wherein the ingredient is at least one ingredient selected from the group consisting of soybean meal, wheat bran and bean curd okara.

[0035] Effects of the Invention

[0036] According to the present disclosure, there is provided a biodegradable resin composition or the like which can produce a molded article having high biodegradability particularly in the ocean even if it contains polybutylene adipate terephthalate as a biodegradable resin. DETAILED DESCRIPTION

[0037] The present disclosure is described below based on specific embodiments. 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.

[0038] 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.

[0039] 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.

[0040] 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”.

[0041] Furthermore, in the present disclosure, “plurality” means “two or more”.

[0042] <Biodegradable resin>

[0043] The biodegradable resin composition contains a biodegradable resin. The biodegradable resin is polybutylene adipate terephthalate.

[0044] Polybutylene adipate terephthalate is a polyester obtained by copolymerizing adipic acid, 1,4-butanediol, and terephthalic acid. Polybutylene adipate terephthalate can be produced by a known production method, or a commercially available product can be used.

[0045] The content of the biodegradable resin contained in the biodegradable resin composition of the present invention is not particularly limited, but in order to ensure the appropriate strength of the molded product of the biodegradable resin composition, it is preferably 50% by weight or more. The content of the biodegradable resin is 50% by weight or more, so the strength of the molded product is improved. It should be noted that even if the content of the biodegradable resin having a tendency to have poor biodegradability in the ocean is a high content of 50% by weight or more in the biodegradable resin composition of the present invention, by including the component that promotes marine degradability described later, the sufficient biodegradability of the molded product in the ocean can also be ensured. In addition, if the content of the component that promotes marine degradability described later is too much in the biodegradable resin composition, it is expected that: the component is difficult to disperse evenly, the component agglomerates in the molded product, and biodegradation is difficult to proceed smoothly. The content of the biodegradable resin is more preferably 70% by weight or more, and more preferably 80% by weight or more. On the other hand, the upper limit of the content of the biodegradable resin is preferably 97% by weight or less, more preferably 95% by weight or less, and further preferably 93% by weight or less, in consideration of the balance between the content and the content of the component promoting marine degradability described later. The content of the biodegradable resin is preferably, for example, 50 to 97% by weight, 70 to 95% by weight, or 80 to 93% by weight.

[0046] <Ingredients that promote marine degradability>

[0047] The biodegradable resin composition disclosed herein contains one or more components selected from the group consisting of soybean-derived substances and wheat bran as components different from the biodegradable resin. The soybean-derived substance is not particularly limited as long as it is a substance derived from soybeans. As specific types, for example, one or more selected from the group consisting of soybean meal, soybean hulls, soybean fibers, bean curd residues, bean curd residue fibers, and soy sauce meal can be cited. As the soybean-derived substance, from the viewpoint of ensuring good biodegradability, one or more selected from the group consisting of soybean meal, soybean hulls, and soybean fibers are preferred.

[0048] Among them, from the viewpoint of ensuring good biodegradability, it is preferred to contain one or more components selected from the group consisting of soybean meal, wheat bran, and bean curd okara.

[0049] By including the above-mentioned components, even if the biodegradable resin composition contains polybutylene adipate terephthalate, a molded article of the biodegradable resin composition exhibits good biodegradability in an environment such as the ocean where it comes into contact with seawater.

[0050] The present inventors presume that the reason for this is that, by including the above-mentioned components in the resin composition and its molded article, microorganisms contained in seawater are easily aggregated on the surface of the molded article, and the above-mentioned components and the biodegradable resin are efficiently assimilated by the microorganisms.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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, or a commercial product can be used.

[0056] 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.

[0057] 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.

[0058] 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 soy sauce meal may be obtained as this by-product or a commercially available product may be used.

[0059] The above components may be used alone or in combination of two or more. Among the above components, soybean meal can be preferably exemplified.

[0060] The above-mentioned component that promotes marine degradability is preferably pulverized according to the thickness of the molded article. For example, the above-mentioned component is preferably pulverized.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] From the perspective of improving the cohesion of microorganisms on the molded article of the resin composition in an environment in contact with seawater such as in the ocean, and then improving its biodegradability, the content of the above-mentioned components in the biodegradable resin composition disclosed herein is preferably 3% by weight or more, more preferably 5% by weight or more, and more preferably 7% by weight or more. On the other hand, the upper limit of the content of the above-mentioned components, considering the content thereof and the content of the above-mentioned biodegradable resin, is preferably 45% by weight or less, more preferably 25% by weight or less, and more preferably 20% by weight or less. Preferably, for example, 3 to 45% by weight, 5 to 25% by weight, and 7 to 20% by weight can be cited.

[0065] In the biodegradable resin composition of the present disclosure, the weight ratio of the biodegradable resin to one or more components selected from the group consisting of soybean-derived substances and wheat bran is 0.5 to 40, preferably 1 to 35, and more preferably 5 to 30, when the biodegradable resin is taken as 100.

[0066] The biodegradable resin composition may contain a carbodiimide group-containing compound.

[0067] The carbodiimide group-containing compound 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 subjecting various polyisocyanates to a decarbonation condensation reaction at a temperature of about 70° C. or above in a solvent-free or inert solvent. There are no particular limitations on the compound as long as it has a carbodiimide group in one molecule, but preferably it is a compound having two or more carbodiimide groups in one molecule.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] The end-capping agent for capping the terminal of the polycarbodiimide compound to control its polymerization degree is not limited to the above-mentioned monoisocyanate compound, but also includes an active hydrogen compound that can react with an isocyanate group, for example: (i) methanol, ethanol, phenol, cyclohexanol, N-methylethanolamine, polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether, which are aliphatic, aromatic or alicyclic compounds and have an -OH group; (ii) diethylamine and dicyclohexylamine having an -NH- group; (iii) 2 (iv) succinic acid, benzoic acid, cyclohexane acid having a -COOH group; (v) ethyl mercaptan, allyl mercaptan, thiophenol having a -SH group; (vi) compounds having an epoxy group; (vii) acid anhydrides such as acetic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, etc.

[0075] Among them, polyethylene glycol monomethyl ether as a compound having an -OH group, dicyclohexylamine as a compound having an -NH- group, or 2 The cyclohexylamine of the compound containing cyclohexylamine is more preferably used.

[0076] The carbodiimide group-containing compound may be used alone or in combination of two or more in any combination and ratio.

[0077] The content of the carbodiimide group-containing compound in the biodegradable resin composition (the total content when multiple compounds are included) is not particularly limited. From the perspective of being able to achieve a good appearance, it is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, and further preferably 0.5% by weight or more. On the other hand, the upper limit of the content of the carbodiimide group-containing compound is preferably 10% by weight or less, more preferably 5% by weight or less, and further preferably 3% by weight or less, in consideration of the content of the above-mentioned biodegradable resin and the content of one or more components selected from the group consisting of soybean-derived substances and wheat bran. 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.

[0078] <Other added ingredients>

[0079] 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, plasticizers, colorants, crosslinking agents, etc.

[0080] <Method for producing biodegradable resin composition>

[0081] The method for producing the biodegradable resin composition of the present disclosure is not particularly limited, and a known method can be used.

[0082] An example of a method for producing a biodegradable resin is a method for producing a biodegradable resin composition comprising the step of mixing at least one component selected from the group consisting of a soybean-derived substance and wheat bran with a biodegradable resin, wherein the biodegradable resin is polybutylene adipate terephthalate.

[0083] The mixing method in the mixing step is not particularly limited, and examples thereof include a method of melt-kneading the mixture of the components at a predetermined temperature, for example, about 120 to 200° C., using various single-screw or multi-screw extruders. The components may be kneaded together, or the remaining components may be added and kneaded after kneading any component.

[0084] <Molding products>

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] More specifically, examples include a method of reducing the content by 20% by weight or more or 15% by weight or more in a molded article having a thickness of 50 μm in a biodegradable resin composition in which soybean meal is added to polybutylene adipate terephthalate; a method of reducing the content by 15% by weight or more or 10% by weight or more when wheat bran is used; and a method of reducing the content by 15% by weight or more or 10% by weight or more when soybean curd okara is used.

[0090] 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).

[0091] Furthermore, as is apparent from the above description, according to the present disclosure, it is preferred to use at least one component selected from the group consisting of soybean-derived substances and wheat bran in order to improve the marine biodegradability of a biodegradable resin composition comprising at least polybutylene adipate terephthalate as a biodegradable resin.

[0092] When the above-specified components are used in preparing a biodegradable resin composition, a resin composition for obtaining a molded article having high marine biodegradability can be provided.

[0093] It should be noted that, with regard to the type of the biodegradable resin composition at this time, the amount thereof added to the resin composition, and the amount of at least one component selected from the group consisting of soybean-derived substances and wheat bran added to the resin composition, the same conditions as those described in the above-mentioned "Biodegradable resin composition" can be applied.

[0094] In addition, the present disclosure also includes a method for improving the marine biodegradability of a molded article of a resin composition, wherein the marine biodegradability of the molded article of the obtained resin composition is improved by mixing at least one or more components selected from the group consisting of a substance derived from soybean and wheat bran with at least polybutylene adipate terephthalate as a biodegradable resin. That is, a method for improving the marine biodegradability of a molded article of the obtained biodegradable resin composition by mixing at least one or more components selected from the group consisting of a substance derived from soybean and wheat bran in a biodegradable resin composition containing at least polybutylene adipate terephthalate as a biodegradable resin. According to the method, the following molded article can be made: a molded article with higher marine biodegradability than a molded article of a biodegradable resin composition that does not contain at least one or more components selected from the group consisting of a substance derived from soybean and wheat bran.

[0095] As described above, by adding at least one component selected from the group consisting of soybean-derived substances and wheat bran to a biodegradable resin composition containing polybutylene adipate terephthalate (a biodegradable resin that is considered to have low marine biodegradability), the marine biodegradability of a molded article of the biodegradable resin composition can be significantly improved.

[0096] It should be noted that, with regard to the type of the biodegradable resin composition at this time, the amount thereof added to the resin composition, and the amount of at least one component selected from the group consisting of soybean-derived substances and wheat bran added to the resin composition, the same conditions as those described in the above-mentioned "Biodegradable resin composition" can be applied.

[0097] In addition, the contents described in the above section <Molded article> can be applied to the molding method of the resin composition obtained by the above method and the use of the molded article thereof.

[0098] [Example]

[0099] Hereinafter, the present disclosure will be specifically described with reference to examples, but the present disclosure is not limited to the embodiments below.

[0100] Soybean meal, wheat bran, bean curd dregs, corn gluten meal, defatted rice bran, casein, soybean hulls, soybean fiber, bean curd dregs fiber, and soy sauce meal were pulverized using a tabletop 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 to serve as raw materials for the following examples and comparative examples.

[0101] <Example 1> Mixing of polybutylene adipate terephthalate (PBAT) and soybean meal

[0102] A resin composition was obtained by mixing (melting and kneading) 90 wt% of polybutylene adipate terephthalate (Mater-biES01G: manufactured by Novamont) and 10 wt% of soybean meal (N7-P1-K1: manufactured by Showa Sangyo Co., Ltd.) at 150°C using a laboratory mixer for 6 minutes. It should be noted that the blank column in the raw material column in Table 1 indicates that no addition was made. In addition, the values ​​of each raw material in Table 1 are weight %.

[0103] <Examples 6 and 10>

[0104] Resin compositions were obtained in the same manner as in Example 1 except that the soybean meal in Example 1 was changed to wheat bran (bran: manufactured by Showa Sangyo Co., Ltd.) and bean curd okara (okara powder: manufactured by Takahashi Co., Ltd.), respectively.

[0105] <Examples 2 to 5, 7 to 9, 11 to 13>

[0106] A resin composition was obtained in the same manner as in Example 1 except that the weight percentages of polybutylene adipate terephthalate and soybean meal, wheat bran or soybean curd okara were set to the values ​​shown in Table 1.

[0107] <Examples 14 to 17>

[0108] Resin compositions were obtained in the same manner as in Example 3 except that the soybean meal in Example 3 was replaced with soybean hulls (manufactured by Shimizu Flour Mill Co., Ltd.), soybean fiber (manufactured by Food Bridge Japan Co., Ltd.), okara fiber (manufactured by Nippon Garlic Co., Ltd.), and soy sauce meal (manufactured by Mitsuru-Shoyu Co., Ltd.).

[0109] <Comparative Example 1>

[0110] A resin composition was obtained in the same manner as in Example 1 except that the soybean meal in Example 1 was not used.

[0111] <Comparative Examples 2 to 4>

[0112] Resin compositions were obtained in the same manner as in Example 1 except that the soybean meal in Example 1 was replaced with corn gluten meal (corn gluten meal: manufactured by Kogoshi Co., Ltd.), defatted rice bran (defatted bran: manufactured by Boso Oil & Fats Co., Ltd.), and casein (casein: manufactured by Kanto Chemical Co., Ltd.).

[0113] <Comparative Example 5>

[0114] A resin composition was obtained in the same manner as in Example 3 except that the polybutylene adipate terephthalate in Example 3 was changed to polylactic acid (Nw-2003D: manufactured by NatureWorks).

[0115] <Marine biodegradability test>

[0116] 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.

[0117] [Evaluation criteria]

[0118] 5: The weight reduction ratio before and after the test is 20% by weight or more.

[0119] 4: The weight reduction ratio before and after the test is 15% by weight or more and less than 20% by weight.

[0120] 3: The weight reduction ratio before and after the test is 10% by weight or more and less than 15% by weight.

[0121] 2: The weight reduction ratio before and after the test is 8% by weight or more and less than 10% by weight.

[0122] 1: The weight reduction ratio before and after the test is less than 8% by weight.

[0123] [Table 1]

[0124]

[0125] In the table, PBAT stands for polybutylene adipate terephthalate, and PLA stands for polylactic acid.

[0126] The evaluation results shown in Table 1 show that the marine biodegradability can be significantly improved by mixing a specific component that promotes marine biodegradability into a biodegradable resin.

[0127] This result suggests that, by making the biodegradable resin composition contain a specific component that promotes marine biodegradability, a large amount of microorganisms in seawater are accumulated in the biodegradable resin in the molded article, thereby improving biodegradability.

[0128] Industrial Applicability

[0129] According to the present disclosure, it is possible to provide a biodegradable resin composition or the like which can be used for producing a molded article having high biodegradability, particularly in the ocean.

Claims

1. A biodegradable resin composition, wherein: The biodegradable resin composition contains a biodegradable resin. The biodegradable resin composition comprises one or more components selected from the group consisting of a soybean-derived substance and wheat bran, The biodegradable resin is polybutylene adipate terephthalate.

2. The biodegradable resin composition according to claim 1, wherein The soybean-derived material 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.

3. The biodegradable resin composition according to claim 1, wherein The biodegradable resin composition includes one or more components selected from the group consisting of soybean meal, wheat bran, and bean curd dregs.

4. The biodegradable resin composition according to any one of claims 1 to 3, wherein The content of the biodegradable resin is 50% by weight or more.

5. The biodegradable resin composition according to any one of claims 1 to 4, wherein The content of the components is 5 to 25% by weight.

6. A molded article, wherein The molded article is a molded article of the biodegradable resin composition according to any one of claims 1 to 5.

7. The molded article according to claim 6, wherein The molded product is in the form of a film.

8. The molded article according to claim 6 or 7, wherein The molded product is used for products in contact with seawater.

9. Use of a molded article, wherein: The molded article is the molded article according to claim 8, and the molded article is used for a product that comes into contact with seawater.

10. A method for producing a biodegradable resin composition, wherein: The method comprises the steps of: mixing at least one component selected from the group consisting of a soybean-derived substance and wheat bran with a biodegradable resin; The biodegradable resin is polybutylene adipate terephthalate.

11. The method for producing a biodegradable resin composition according to claim 10, wherein: The component is at least one component selected from the group consisting of soybean meal, wheat bran and bean curd dregs.

12. Use of a composition, wherein: The component is at least one component selected from the group consisting of a soybean-derived substance and wheat bran, and the component is used for preparing a biodegradable resin composition containing at least polybutylene adipate terephthalate as a biodegradable resin.

13. Use of a composition according to claim 12, wherein The component is at least one component selected from the group consisting of soybean meal, wheat bran and bean curd dregs.

14. A method for improving the marine biodegradability of a molded article of a biodegradable resin composition, wherein: By mixing at least one component selected from the group consisting of soybean-derived substances and wheat bran with at least polybutylene adipate terephthalate as a biodegradable resin, the marine biodegradability of a molded article of the obtained biodegradable resin composition is improved.

15. The method according to claim 14, wherein: The component is at least one component selected from the group consisting of soybean meal, wheat bran and bean curd dregs.

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