Molded article of biodegradable resin

Abstract

To provide a molded article of a biodegradable resin composition with improved biodegradability.SOLUTION: A molded article of a biodegradable resin composition comprises a biodegradable resin and a biodegradable resin degradation accelerator. The biodegradable resin degradation accelerator is a polyester having a repeating unit represented by the specified general formula (A) and a repeating unit represented by the specified general formula (G), or a polyester having a repeating unit represented by the specified general formula (L), a repeating unit represented by the specified general formula (A) and a repeating unit represented by the specified general formula (G), the polyester having a carboxyl group at at least one terminal end.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a molded article of a biodegradable resin. More specifically, it relates to a molded article of a biodegradable resin composition containing a predetermined biodegradability promoter.

Background Art

[0002] In response to the microplastic problem and the problem of waste disposal volume, the movement to replace general-purpose plastics with biodegradable plastics is accelerating globally, and the demand for biodegradable plastics is expected to increase significantly worldwide. However, since biodegradable plastics require a long time to decompose in the natural environment, the development of technologies to shorten the decomposition time is required.

[0003] The decomposition of biodegradable resins can be promoted by placing them in a high-temperature and high-humidity environment. However, for further promotion of biodegradability, additives for improving the biodegradability of biodegradable resins have been developed (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Development leveraging the characteristics of biodegradable resins is underway, and molded articles having biodegradability in a wider range of applications than before are required. The problem to be solved by the present invention is to provide a molded article of a biodegradable resin composition with improved biodegradability.

Means for Solving the Problems

[0006] As a result of intensive studies to solve the above problems, the inventors of the present invention developed a novel biodegradability promoter (Japanese Patent Application No. 2022-74414). As a result of further evaluating the performance of the biodegradability promoter, it was found that excellent effects can be obtained in various molded articles.

[0007] According to the present invention, there is provided a molded article of a biodegradable resin composition containing a biodegradable resin and a polyester having a repeating unit represented by the following general formula (A), a repeating unit represented by the following general formula (G), or a polyester having a repeating unit represented by the following general formula (L), a repeating unit represented by the following general formula (A), and a repeating unit represented by the following general formula (G), and being a polyester having a carboxyl group at at least one end, which is a biodegradable resin decomposition promoter.

Chemical formula

Advantages of the Invention

[0008] According to the present invention, there can be provided a molded article of a biodegradable resin composition with improved biodegradability.

Modes for Carrying Out the Invention

[0009] Hereinafter, an embodiment of the present invention will be described. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the range that does not impair the effects of the present invention.

[0010] The molded article of the present invention is a biodegradable resin composition containing a biodegradable resin, a polyester having a repeating unit represented by the following general formula (A) and a repeating unit represented by the following general formula (G), or a polyester having a repeating unit represented by the following general formula (L), a repeating unit represented by the following general formula (A), and a repeating unit represented by the following general formula (G), and a biodegradable resin decomposition accelerator containing a polyester having a carboxyl group at at least one end.

[0011] [Chemical formula] (In the general formulas (A), (G), and (L), A is an aliphatic dibasic acid residue having 0 to 12 carbon atoms or an aromatic dibasic acid residue having 5 to 15 carbon atoms, G is an aliphatic diol residue having 2 to 12 carbon atoms, L is a hydroxycarboxylic acid residue having 2 to 18 carbon atoms.)

[0012] In the molded article of the present invention, by using the above biodegradable resin decomposition accelerator, the decomposition of the molded article can be promoted. The biodegradable resin decomposition accelerator used in the present invention is insoluble in water, unlike conventional phosphorus-based and nitrogen-based decomposition accelerators, so its outflow from the molded article during decomposition is suppressed. That is, since the biodegradable resin decomposition accelerator remains in the molded article for a long time, the decomposition of the biodegradable resin is efficiently promoted. In addition, the biodegradable resin decomposition accelerator used in the present invention has higher degradability by enzymes and water than conventional biodegradable resin decomposition accelerators. Therefore, it exhibits high decomposition promoting properties not only in a high-temperature and high-humidity (60 to 80 °C) environment such as industrial compost, but also in a more natural environment such as ordinary soil or the ocean. Furthermore, at the time of molding the biodegradable resin composition, the biodegradable resin decomposition accelerator used in the present invention has high compatibility with the biodegradable resin, so it has good processability and can be molded into various shapes. Hereinafter, the biodegradable resin composition constituting the molded article of the present invention and specific uses will be described.

[0013] 1. Biodegradable resin composition [Biodegradable resin] Examples of the biodegradable resin contained in the biodegradable resin composition include polylactic acid (PLA), polyethylene succinate (PES), polyethylene terephthalate - succinate (PETS), polybutylene succinate (PBS), polybutylene adipate - terephthalate (PBAT), polyethylene adipate - terephthalate (PEAT), polybutylene succinate - terephthalate (PBST), polyethylene succinate - terephthalate (PEST), polybutylene succinate - adipate (PBSA), polybutylene succinate - carbonate (PEC), polybutylene succinate - adipate - terephthalate (PBSAT), polyethylene succinate - adipate - terephthalate (PESAT), polytetramethylene adipate - terephthalate (PTMAT), polyhydroxybutyric acid (PHB), polyhydroxybutyric acid - hydroxyhexanoic acid (PHBH), polycaprolactone (PCL), polycaprolactone - butylene succinate (PCLBS), cellulose acetate, and the like. The biodegradable resin to be used may be determined according to the intended use, and the above biodegradable resin may be used alone or in combination of two or more.

[0014] The biodegradable resin is preferably at least one selected from the group consisting of polylactic acid, polybutylene succinate, polybutylene adipate terephthalate, polyhydroxybutyric acid - hydroxyhexanoic acid, polybutylene succinate adipate, and polyethylene terephthalate succinate.

[0015] [Biodegradable resin decomposition accelerator] The biodegradable resin decomposition accelerator is a polyester having a repeating unit represented by the following general formula (A) and a repeating unit represented by the following general formula (G), or a polyester having a repeating unit represented by the following general formula (L), a repeating unit represented by the following general formula (A), and a repeating unit represented by the following general formula (G), and is a polyester having a carboxyl group at at least one end.

[0016] [Chemical formula] (In the general formulas (A), (G), and (L), A is an aliphatic dibasic acid residue having 0 to 12 carbon atoms or an aromatic dibasic acid residue having 5 to 15 carbon atoms, G is an aliphatic diol residue having 2 to 12 carbon atoms, L is a hydroxycarboxylic acid residue having 2 to 18 carbon atoms.)

[0017] The polyester that is the biodegradable resin decomposition accelerator (hereinafter sometimes referred to as "the polyester of the present invention") is presumed to be able to promote the decomposition of the biodegradable resin by the polyester itself functioning as an acid catalyst.

[0018] The polymerization form of the polyester is not particularly limited, and it may be a random copolymer containing the above repeating unit or a block copolymer containing the above repeating unit.

[0019] The polyester is more preferably a polyester represented by the following general formula (1) and / or a polyester represented by the following general formula (2).

[0020] [Chemical formula] (In the general formulas (1) and (2), A1, A2, and A3 are each independently an aliphatic dibasic acid residue having 0 to 12 carbon atoms or an aromatic dibasic acid residue having 5 to 15 carbon atoms, G1 and G2 are each independently an aliphatic diol residue having 2 to 12 carbon atoms, n represents the number of repetitions and is an integer in the range of 0 to 20. However, A1 and G1 may each be the same or different for each repeating unit enclosed in parentheses. )

[0021] In the present invention, the "dibasic acid residue" is an organic group obtained by removing the basic acid functional group from a dibasic acid. For example, when the dibasic acid residue is a dicarboxylic acid residue, the dicarboxylic acid residue refers to the remaining organic group after removing the carboxyl group possessed by the dicarboxylic acid. Regarding the number of carbon atoms of the dicarboxylic acid residue, the carbon atom in the carboxyl group is not included. Therefore, for example, the oxalic acid residue is a dicarboxylic acid residue having 0 carbon atoms, and in the case of the oxalic acid residue, A1, A2, and A3 are single bonds. In the present invention, the "diol residue" refers to the remaining organic group obtained by removing the hydroxyl group from a diol. In the present invention, the "hydroxycarboxylic acid residue" refers to the remaining organic group obtained by removing the hydroxyl group and the carboxyl group from a hydroxycarboxylic acid. Regarding the number of carbon atoms of the hydroxycarboxylic acid residue, the carbon atom in the carboxyl group is not included.

[0022] The aliphatic dibasic acid residues of A, A1, A2, and A3 having 0 to 12 carbon atoms may contain an alicyclic structure and / or an ether bond (-O-). The aliphatic dibasic acid residues of A, A1, A2, and A3 having 0 to 12 carbon atoms are preferably aliphatic dicarboxylic acid residues having 0 to 12 carbon atoms. Examples of the aliphatic dicarboxylic acid residues having 0 to 12 carbon atoms include oxalic acid residue, succinic acid residue, adipic acid residue, maleic acid residue, pimelic acid residue, suberic acid residue, azelaic acid residue, sebacic acid residue, cyclohexanedicarboxylic acid residue, dodecanedicarboxylic acid residue, hexahydrophthalic acid residue, and the like.

[0023] The aliphatic dibasic acid residues of A, A1, A2 and A3 having 0 to 12 carbon atoms are preferably aliphatic dicarboxylic acid residues having 2 to 12 carbon atoms, more preferably aliphatic dicarboxylic acid residues having 2 to 10 carbon atoms, still more preferably succinic acid residues, sebacic acid residues, maleic acid residues, adipic acid residues, and particularly preferably succinic acid residues, sebacic acid residues, maleic acid residues.

[0024] The aromatic rings of the aromatic dibasic acid residues of A, A1, A2 and A3 having 5 to 15 carbon atoms include those in which some of the carbon atoms of the aromatic ring are replaced by heteroatoms. Examples of the aromatic ring in which some of the carbon atoms are replaced by heteroatoms include a furan ring, an imidazole ring, an oxazole ring and the like.

[0025] The aromatic dibasic acid residues of A, A1, A2 and A3 having 5 to 15 carbon atoms are preferably aromatic dicarboxylic acid residues having 6 to 15 carbon atoms, and specific examples include phthalic acid residues and furandicarboxylic acid residues.

[0026] A, A1, A2 and A3 are preferably aliphatic dibasic acid residues having 2 to 12 carbon atoms, more preferably aliphatic dicarboxylic acid residues having 2 to 12 carbon atoms, and still more preferably aliphatic dicarboxylic acid residues having 2 to 10 carbon atoms.

[0027] In A1, A2 and A3, preferably A1 and A2 are different from each other and / or A1 and A3 are different from each other.

[0028] Examples of the aliphatic diol residues having 2 to 12 carbon atoms for G, G1 and G2 include ethylene glycol residue, 1,2-propylene glycol residue, 1,3-propylene glycol residue, 1,2-propanediol residue, 1,3-propanediol residue, 1,2-butanediol residue, 1,3-butanediol residue, 2-methyl-1,3-propanediol residue, 1,4-butanediol residue, 1,5-pentanediol residue, 2,2-dimethyl-1,3-propanediol (neopentyl glycol) residue, 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane) residue, 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane) residue, 3-methyl-1,5-pentanediol residue, 1,6-hexanediol residue, 2,2,4-trimethyl-1,3-pentanediol residue, 2-ethyl-1,3-hexanediol residue, 2-methyl-1,8-octanediol residue, 1,9-nonanediol residue and the like.

[0029] The aliphatic diol residues having 2 to 12 carbon atoms for G, G1 and G2 may contain an alicyclic structure and / or an ether bond (-O-). Examples of the aliphatic diol residues having 2 to 12 carbon atoms and containing the alicyclic structure include 1,3-cyclopentanediol residue, 1,2-cyclohexanediol residue, 1,3-cyclohexanediol residue, 1,4-cyclohexanediol residue, 1,2-cyclohexanedimethanol residue, 1,4-cyclohexanedimethanol residue and the like. Examples of the aliphatic diol residues having 2 to 12 carbon atoms and containing the ether bond include diethylene glycol residue, triethylene glycol residue, tetraethylene glycol residue, dipropylene glycol residue, tripropylene glycol residue and the like.

[0030] The aliphatic diol residues of G, G1, and G2 having 2 to 12 carbon atoms are preferably aliphatic diol residues having 3 to 8 carbon atoms, more preferably ethylene glycol residue, diethylene glycol residue, 1,3 - propylene glycol, 1,6 - hexanediol or 1,4 - butanediol. G, G1, and G2 can enhance the compatibility with biodegradable resins by using linear aliphatic diol residues.

[0031] Examples of the hydroxycarboxylic acid residues of L having 2 to 18 carbon atoms include residues of hydroxycarboxylic acids in which one hydroxyl group is substituted on the aliphatic chain of aliphatic carboxylic acids having 3 to 19 carbon atoms such as propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, capric acid, caprylic acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, etc. Specific examples include lactic acid residue, 9 - hydroxystearic acid residue, 12 - hydroxystearic acid residue, 6 - hydroxycaproic acid residue, etc.

[0032] The hydroxycarboxylic acid residues of L having 2 to 18 carbon atoms are preferably aliphatic hydroxycarboxylic acid residues having 4 to 18 carbon atoms, more preferably 12 - hydroxystearic acid residue.

[0033] The repeating number of n is an integer in the range of 0 to 20, preferably an integer in the range of 1 to 20, more preferably an integer in the range of 3 to 20, and still more preferably an integer in the range of 5 to 20.

[0034] The number average molecular weight (Mn) of the polyester of the present invention is, for example, in the range of 100 to 6,000, preferably in the range of 300 to 5,000, more preferably in the range of 600 to 5,000, still more preferably in the range of 800 to 5,000, and particularly preferably in the range of 1,000 to 5,000. The above number average molecular weight (Mn) is a value converted to polystyrene based on gel permeation chromatography (GPC) measurement and is measured by the method described in the examples.

[0035] The acid value of the polyester of the present invention is, for example, 25 or more, preferably 27 or more, 30 or more, 40 or more, 50 or more, and more preferably more than 50 in this order. The upper limit of the acid value of the polyester of the present invention is not particularly limited, but is, for example, 400 or less, preferably 250 or less, 200 or less, 150 or less, 120 or less, 100 or less, and more preferably 95 or less in this order.

[0036] The hydroxyl value of the above-mentioned polyester may be, for example, 0 or more, preferably in the range of 10 to 200, more preferably in the range of 20 to 150, and still more preferably in the range of 30 to 120.

[0037] The properties of the above polyester vary depending on the number average molecular weight, composition, etc., but are usually liquid, solid, paste-like, etc. at room temperature (25 ° C), preferably solid or liquid at room temperature (25 ° C), and more preferably solid at room temperature (25 ° C).

[0038] The above polyester is obtained by using reaction raw materials including an aliphatic dibasic acid and / or an aromatic dibasic acid, an aliphatic diol, and an optional hydroxycarboxylic acid. Here, the reaction raw material means a raw material constituting the polyester of the present invention and does not include a solvent or a catalyst that does not constitute the polyester. Further, "optional hydroxycarboxylic acid" means that a hydroxycarboxylic acid may or may not be used. The method for producing the polyester of the present invention is not particularly limited and can be produced by a known method or a production method described later.

[0039] The reaction raw materials of the polyester may include an aliphatic dibasic acid and / or an aromatic dibasic acid, an aliphatic diol, and an optional hydroxycarboxylic acid, and may also include other raw materials. The reaction raw materials of the polyester of the present invention preferably include, based on the total amount of the reaction raw materials, 90% by mass or more of an aliphatic dibasic acid and / or an aromatic dibasic acid, an aliphatic diol, and an optional hydroxycarboxylic acid, and more preferably consist only of an aliphatic dibasic acid and / or an aromatic dibasic acid, an aliphatic diol, and an optional hydroxycarboxylic acid.

[0040] The aliphatic dibasic acid used in the production of the polyester is an aliphatic dibasic acid corresponding to the aliphatic dibasic acid residues having 2 to 12 carbon atoms of A, A1, A2, and A3. The aliphatic dibasic acid used may be used alone or in combination of two or more. The aromatic dibasic acid used in the production of the polyester is an aromatic dibasic acid corresponding to the aromatic dibasic acid residues having 5 to 15 carbon atoms of A, A1, A2, and A3. The aromatic dibasic acid used may be used alone or in combination of two or more. The aliphatic diol used in the production of the polyester is an aliphatic diol corresponding to the aliphatic diol residues having 2 to 12 carbon atoms of G, G1, and G2. The aliphatic diol used may be used alone or in combination of two or more. The hydroxycarboxylic acid used in the production of the polyester is a hydroxycarboxylic acid corresponding to the hydroxycarboxylic acid residues having 2 to 18 carbon atoms of L. The hydroxycarboxylic acid used may be used alone or in combination of two or more. The reaction raw materials used also include derivatives such as the above esterified products, the above acid chlorides, and the above acid anhydrides. For example, the hydroxycarboxylic acid also includes compounds having a lactone structure such as ε-caprolactone.

[0041] The polyester can be produced by reacting an aliphatic dibasic acid and / or an aromatic dibasic acid, an aliphatic diol, and an optional hydroxycarboxylic acid that constitute each residue of the polyester under the condition that the equivalent amount of the carboxyl group contained in the reaction raw materials is the same as or more than the equivalent amount of the hydroxyl group. The polyester can also be produced by reacting an aliphatic dibasic acid and / or an aromatic dibasic acid, an aliphatic diol, and an optional hydroxycarboxylic acid that constitute each residue of the polyester under the condition that the equivalent of the hydroxyl group contained in the reaction raw materials is more than the equivalent of the carboxyl group to obtain a polyester having a hydroxyl group at the end of the main chain, and then reacting the obtained polyester with an aliphatic dibasic acid and / or an aromatic dibasic acid.

[0042] The polyester is preferably a polyester using, as reaction raw materials, one or more aliphatic dibasic acids selected from the group consisting of succinic acid, sebacic acid, maleic acid, and adipic acid residues, and one or more aliphatic diols selected from ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, cyclohexanedimethanol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, and 1,9-nonanediol.

[0043] The polyester is more preferably a polyester using, as reaction raw materials, one or more aliphatic dibasic acids selected from the group consisting of succinic acid and sebacic acid, and one or more aliphatic diols selected from ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-butanediol, and 1,3-butanediol. All of these reaction raw materials can be derived from biomass, and the obtained polyester can be made into a polyester with 100% biomass content. Using a polyester with 100% biomass content in a biodegradable resin is preferable from the perspective of sustainability.

[0044] In the production of polyester, the reaction of the reaction raw materials may be carried out as an esterification reaction in the presence of an esterification catalyst if necessary, for example, within a temperature range of 180 to 250 °C for 10 to 25 hours. In addition, conditions such as the temperature and time of the esterification reaction are not particularly limited and may be set as appropriate.

[0045] Examples of the esterification catalyst include titanium-based catalysts such as tetraisopropyl titanate and tetrabutyl titanate; zinc-based catalysts such as zinc acetate; tin-based catalysts such as dibutyltin oxide; and organic sulfonic acid-based catalysts such as p-toluenesulfonic acid.

[0046] The amount of the esterification catalyst used may be set as appropriate, but it is usually used in the range of 0.001 to 0.1 parts by mass with respect to 100 parts by mass of the total amount of the reaction raw materials.

[0047] [Biodegradable resin composition] The biodegradable resin composition used in the present invention contains the above-described biodegradable resin decomposition accelerator and a biodegradable resin. By containing the biodegradable resin decomposition accelerator in the biodegradable resin composition, the decomposition of the biodegradable resin can be further promoted. In addition, the biodegradable resin decomposition accelerator can also function as a plasticizer for the biodegradable resin. For example, a molded product can be produced from the biodegradable resin composition without using conventional plasticizers such as benzoic acid esters, phthalic acid esters, and pyromellitic acid esters.

[0048] The content of the biodegradable resin decomposition accelerator is not particularly limited, but for example, it is in the range of 1 to 250 parts by mass, preferably in the range of 1 to 50 parts by mass, and more preferably in the range of 1 to 30 parts by mass with respect to 100 parts by mass of the biodegradable resin.

[0049] The biodegradable resin composition of the present invention may contain an inorganic filler. The inorganic filler contained in the biodegradable resin composition is not particularly limited, and examples thereof include calcium carbonate, talc, silica, alumina, clay, antimony oxide, aluminum hydroxide, magnesium hydroxide, hydrotalcite, calcium silicate, magnesium oxide, potassium titanate, barium titanate, titanium oxide, calcium oxide, magnesium oxide, manganese dioxide, boron nitride, aluminum nitride, and the like. The inorganic filler may be used alone or in combination of two or more.

[0050] The inorganic filler is preferably at least one selected from the group consisting of calcium carbonate, silica, alumina, aluminum hydroxide, barium titanate, talc, boron nitride, and aluminum nitride, and more preferably at least one selected from the group consisting of calcium carbonate, alumina, aluminum hydroxide, and talc.

[0051] The shape of the inorganic filler, such as particle size, fiber length, and fiber diameter, is not particularly limited and may be appropriately adjusted according to the intended use. Also, the surface treatment state of the inorganic filler is not particularly limited, and surface modification may be performed with, for example, saturated fatty acids according to the intended use.

[0052] The content of the inorganic filler is, for example, in the range of 1 to 200 parts by mass with respect to 100 parts by mass of the biodegradable resin, and may also be in the range of 1 to 100 parts by mass, 5 to 70 parts by mass, 10 to 60 parts by mass, or 15 to 55 parts by mass.

[0053] As described above, the biodegradable resin decomposition accelerator can also function as a plasticizer, but the biodegradable resin composition may further contain a plasticizer other than the above-described biodegradable resin decomposition accelerator. Examples of the plasticizer include benzoic acid esters such as diethylene glycol dibenzoate; phthalic acid esters such as dibutyl phthalate (DBP), di-2-ethylhexyl phthalate (DOP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), diundecyl phthalate (DUP), ditridecyl phthalate (DTDP); terephthalic acid esters such as bis(2-ethylhexyl) terephthalate (DOTP); isophthalic acid esters such as bis(2-ethylhexyl) isophthalate (DOIP); pyromellitic acid esters such as tetra-2-ethylhexyl pyromellitate (TOPM); aliphatic dibasic acid esters such as di-2-ethylhexyl adipate (DOA), diisononyl adipate (DINA), diisodecyl adipate (DIDA), di-2-ethylhexyl sebacate (DOS), diisononyl sebacate (DINS); phosphate esters such as tri-2-ethylhexyl phosphate (TOP), tricresyl phosphate (TCP); alkyl esters of polyhydric alcohols such as pentaerythritol; polyesters having a molecular weight of 800 to 4,000 synthesized by polyesterification of dibasic acids such as adipic acid and glycol; epoxidized esters such as epoxidized soybean oil and epoxidized linseed oil; alicyclic dibasic acids such as diisononyl hexahydrophthalate; fatty acid glycol esters such as 1,4-butanediol dicaprate; tributyl acetylcitrate (ATBC); chlorinated paraffin obtained by chlorinating paraffin wax or n-paraffin; chlorinated fatty acid esters such as chlorinated stearic acid ester; and higher fatty acid esters such as butyl oleate, etc. The plasticizer to be used may be determined according to the intended use, and the above plasticizers may be used alone or in combination of two or more.

[0054] Although the content of the plasticizer is not particularly limited, for example, it is preferably in the range of 10 to 300 parts by mass, more preferably in the range of 20 to 200 parts by mass, based on 100 parts by mass of the biodegradable resin.

[0055] The additives contained in the biodegradable resin composition are not limited to the biodegradable resin decomposition accelerator and the plasticizer, and may include other additives other than these. Examples of the other additives include, for example, viscosity reducers, flame retardants, stabilizers, stabilization aids, colorants, processing aids, fillers, antioxidants (anti-aging agents), ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, crosslinking aids, and the like.

[0056] Further, the biodegradable resin composition may contain a non-biodegradable resin as long as the effects of the present invention are not impaired. The non-biodegradable resin is not particularly limited, and examples thereof include polyolefin, polyester, polysulfide, polyvinyl chloride, modified polysulfide, silicone resin, modified silicone resin, acrylic urethane resin, epoxy resin, polyurethane, acrylic resin, polyester, unsaturated polyester, and the like.

[0057] [Method for producing biodegradable resin composition] The method for producing the biodegradable resin composition used in the present invention is not particularly limited. For example, it can be obtained by a method of melt-kneading a biodegradable resin, an inorganic filler, and a fluidity modifier, and optionally a plasticizer and the above other additives using a melt-kneading machine such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a Brabender, or various kneaders.

[0058] [Method for producing molded article] The molded article of the present invention can be obtained by molding the biodegradable resin composition of the present invention by various molding methods applied to general-purpose plastics. Examples of the above molding methods include compression molding (compression molding, lamination molding, stampable molding), injection molding, extrusion molding, and co-extrusion molding (film molding by the inflation method or T-die method, laminate molding, pipe molding, wire / cable molding, molding of profiled materials), hot press molding, hollow molding (various blow molding), calendar molding, solid molding (uniaxial stretching molding, biaxial stretching molding, roll rolling molding, stretch-oriented nonwoven fabric molding, thermoforming (vacuum forming, pressure-air forming), plastic working, powder molding (rotational molding), various nonwoven fabric moldings (dry method, adhesion method, entanglement method, spunbond method, etc.). Injection molding, extrusion molding, compression molding, or hot press molding is preferably applied. As specific shapes, application to sheets, films, and containers is preferred.

[0059] The molded body obtained above may be subjected to secondary processing. Examples of such secondary processing include embossing, painting, adhesion, printing, metallizing (such as plating), machining, surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, coating, etc.).

[0060] [Uses of the Molded Body] The molded body obtained from the biodegradable resin composition of the present invention is suitably used for a wide range of applications such as packaging materials for packaging liquids, powders, and solids, agricultural materials, and building materials. Specific uses include injection molded products (for example, trays for fresh food, containers for fast food, containers for coffee capsules, cutlery, outdoor leisure products, etc.), extrusion molded products (for example, films, sheets, fishing lines, fishing nets, vegetation nets, sheets for secondary processing, water retention sheets, etc.), hollow molded products (bottles, etc.).

[0061] In addition, it can also be used for agricultural films, coating materials, coating materials for fertilizers, seedling raising pots, laminated films, plates, stretched sheets, monofilaments, non-woven fabrics, flat yarns, staples, crimped fibers, ribbed tapes, split yarns, composite fibers, blow bottles, shopping bags, garbage bags, compost bags, cosmetic containers, detergent containers, bleach containers, ropes, binding materials, cover stock materials for hygiene, cool boxes, cushion material films, multifilaments, synthetic papers, surgical threads, sutures, artificial bones, artificial skins, microcapsules, wound dressing materials, etc. for medical use.

[0062] Furthermore, for example, it can be suitably used for microbial carriers, animal plankton breeding equipment, water treatment carriers, foams, drain materials, downhole tool members, plug plugs, shells for shooting fireworks, battery materials, capacitors, sensors, shape memory materials, and stents.

[0063] The microbial carrier of one embodiment is used for water purification and can, for example, improve denitrification efficiency. The shape of the microbial carrier is not particularly limited, and examples include film-like, pellet-like, and hollow cylindrical shapes. In order to increase the surface area of the carrier, it may be a porous body. Also, it is possible to make a rod-shaped carrier having a cross-sectional shape with a low porosity of a microbial carrier containing a biodegradable resin and having a recess on the outer periphery. The microbial carrier according to the present embodiment can be used for supporting various microorganisms, and the types of microorganisms are not particularly limited. As the microorganisms, denitrifying bacteria, particularly heterotrophic denitrifying bacteria, are preferably mentioned. Among them, as will be described later, since the oxygen concentration in the vicinity of the biofilm in which the supported microorganisms aggregate in a film shape can be reduced, it can be preferably used for supporting anaerobic microorganisms, for example, denitrifying bacteria that perform denitrification under anaerobic conditions. When the microbial carrier according to this embodiment is used for supporting heterotrophic microorganisms, such as denitrifying bacteria, it is preferable to support biodegradable resin-degrading bacteria having the ability to degrade the biodegradable resin together with the denitrifying bacteria. By the biodegradable resin-degrading bacteria degrading the biodegradable resin in the microbial carrier, carbon necessary for denitrifying nitrite nitrogen and / or nitrate nitrogen in the water to be treated is sufficiently supplied to the denitrifying bacteria. As a result, the growth, growth, activities, etc. of the denitrifying bacteria are promoted, and the denitrification rate and the denitrification amount can be improved. Note that the denitrifying bacteria, biodegradable resin-degrading bacteria, etc. can be appropriately selected and used from known bacteria. As the biodegradable resin, a biodegradable polyester with high degradability is preferable. Among biodegradable polyesters, a biodegradable polyester having a structural unit derived from a dicarboxylic acid with particularly high degradability is preferable, and a biodegradable polyester having a structural unit derived from a dicarboxylic acid and a structural unit derived from a diol is more preferable. The microbial carrier has, for example, a rod shape, a shape in which a cross section perpendicular to the longitudinal direction has a recess on the outer periphery, and an outer peripheral length ratio of 0.5 mm -1 or more and 4.5 mm -1 or less. Note that the recess on the outer periphery of the cross section of the microbial carrier is derived from a groove continuously formed in the longitudinal direction of the microbial carrier. When a microbial carrier having such a shape is used for water treatment by supporting microorganisms, the water treatment efficiency, particularly the denitrification efficiency, can be improved compared to conventional microbial carriers. Regarding the microbial carrier, reference can be made to JP-A-2022-153873.

[0064] The breeding facility for zooplankton of one embodiment has a culture water tank for accommodating the culture water of zooplankton and a molded body of a biodegradable resin composition. Since the molded body of the biodegradable resin composition is accommodated in the culture water tank, the culture water during cultivation contains the biodegradable resin together with the zooplankton, thereby promoting the growth of the zooplankton. The breeding equipment for zooplankton in one embodiment includes a culture water tank, an air diffuser pipe, a blower, a drain pipe, a drain valve, a food tank for zooplankton, and a food supply pump for zooplankton. An air diffuser pipe is installed in the culture water tank, and the blower installed outside the culture water tank is connected to the air diffuser pipe by a pipe. Further, a drain pipe is connected to the culture water tank, and a drain valve is provided in the drain pipe. Furthermore, the culture water tank and the food tank are connected by a pipe provided with a food supply pump.

[0065] The water treatment apparatus in one embodiment includes a water storage tank in which water to be treated is stored, a denitrification tank containing a denitrification carrier supporting denitrifying bacteria, and a microbial reduction treatment unit that reduces the number of aerobic heterotrophic bacteria in the water to be treated. The microbial reduction treatment unit is disposed in the middle of the transfer path of the water to be treated from the water storage tank to the denitrification tank. By using a molded body of a biodegradable resin composition as the denitrification carrier, the consumption of the denitrification carrier associated with the denitrification treatment is small, and the denitrification rate per unit weight of the denitrification carrier can be improved.

[0066] The foam in one embodiment is obtained by foam molding a molded body of a biodegradable resin composition. Since the biodegradable resin composition has suitable melt tension and high gas retention, it has good foam moldability and shapeability, suppresses the generation of swirl marks, and has a good appearance. The shape of the foam is not particularly restricted, and various shapes such as container shape, plate shape, cylindrical shape, columnar shape, sheet shape, board shape, and block shape can be mentioned. It can be used for daily sundries, toys, industrial materials, industrial supplies, heat insulating materials and cushioning materials for cool boxes.

[0067] The drain material in one embodiment is used in the plastic board drainage method. For example, it is composed of a plate-shaped core material having groove stripes extending in the entire longitudinal direction on at least one side, and a sheet-shaped water permeable material covering at least the surface of the core material where the groove stripes are formed, and the plate-shaped core material is made of a molded body of a biodegradable resin composition. Thereby, the drain material structure is maintained until the period until the consolidation strengthening of the soil is achieved, and it becomes a drain material that is rapidly decomposed after the consolidation strengthening of the soil.

[0068] The shell for percussion fireworks in one embodiment uses a biodegradable resin composition that can be completely or partially decomposed by microorganisms in soil or water (including seawater) as a matrix, and is formed by mixing a biodegradable resin that is incompatible with this matrix or natural organic materials such as wood powder or rice husks that do not dissolve. By doing so, it has a non-uniform structure with a network-like interface that is weaker than the matrix strength, so that it is crushed at the network-like interface by the pressure during explosion and fragmented into pieces about several millimeters in size.

[0069] The downhole tool member in one embodiment can be used as a member of a frac plug. Among them, it is preferably used as a mandrel, rod string, socket, cone, ball or ball seat of a frac plug. By making the downhole tool member into a molded body of a biodegradable resin composition, it can be formed into a secondary molded product of a desired shape, particularly a downhole tool member provided in a plug for plugging, by machining such as cutting, drilling, and cutting.

[0070] The biodegradable stent in one embodiment includes a stent body formed by making a plurality of filament threads made of a molded body of a biodegradable resin composition into a cylindrical braided cord, and elastic threads are arranged in the length direction on the outside of the stent body. This elastic thread is arranged in at least a part of the length direction including the vicinity of each end of the stent body. One end of this elastic thread is fixed near the end of the stent body, and the other end is fixed at a part of the stent body. And in a state where the diameter of the stent body is reduced, tension is applied to the elastic thread. Thereby, when expanding from the reduced diameter state, a force that expands the stent body in the outer direction by the contraction force of the elastic thread acts on the vicinity of each end of the stent body, so that it is possible to reliably expand the end of the stent body.

[0071] In addition, since the molded body of the present invention has biocompatibility and biodegradability, it can be used for medical sensors, shape memory materials, battery materials, capacitors, etc. for which these properties are required.

Examples

[0072] Hereinafter, the present invention will be specifically described by way of Examples and Comparative Examples. It should be noted that the present invention is not limited to the following Examples. In the Examples of the present application, the values of acid value, hydroxyl value, and viscosity are the values evaluated by the following methods. <Method for Measuring Acid Value> Measured by a method in accordance with JIS K0070-1992. <Method for Measuring Hydroxyl Value> Measured by a method in accordance with JIS K0070-1992.

[0073] In the Examples of the present application, the number average molecular weight of the polyester is the value converted to polystyrene based on GPC measurement, and the measurement conditions are as follows. [GPC Measurement Conditions] Measuring device: High-speed GPC device "HLC-8320GPC" manufactured by Tosoh Corporation Column: "TSK GURDCOLUMN SuperHZ-L" manufactured by Tosoh Corporation + "TSK gel SuperHZM-M" manufactured by Tosoh Corporation + "TSK gel SuperHZM-M" manufactured by Tosoh Corporation + "TSK gel SuperHZ-2000" manufactured by Tosoh Corporation + "TSK gel SuperHZ-2000" manufactured by Tosoh Corporation Detector: RI (differential refractometer) Data processing: "EcoSEC Data Analysis version 1.07" manufactured by Tosoh Corporation Column temperature: 40 °C Developing solvent: Tetrahydrofuran Flow rate: 0.35 mL / min Measurement sample: A solution obtained by dissolving 7.5 mg of the sample in 10 ml of tetrahydrofuran and filtering the resulting solution through a microfilter was used as the measurement sample. Sample injection volume: 20 μl Standard sample: The following monodisperse polystyrene with a known molecular weight was used in accordance with the measurement manual of the "HLC-8320GPC".

[0074] (Monodisperse Polystyrene) "A-300" manufactured by Tosoh Corporation "A-500" manufactured by Tosoh Corporation "A-1000" manufactured by Tosoh Corporation "A-2500" manufactured by Tosoh Corporation "A-5000" manufactured by Tosoh Corporation "F-1" manufactured by Tosoh Corporation "F-2" manufactured by Tosoh Corporation "F-4" manufactured by Tosoh Corporation "F-10" manufactured by Tosoh Corporation "F-20" manufactured by Tosoh Corporation "F-40" manufactured by Tosoh Corporation "F-80" manufactured by Tosoh Corporation "F-128" manufactured by Tosoh Corporation "F-288" manufactured by Tosoh Corporation

[0075] (Synthesis Example 1: Synthesis of Biodegradable Resin Degradation Accelerator A) 800 g of sebacic acid, 392 g of 1,3 - propylene glycol, and 0.07 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2 - liter four - necked flask equipped with a thermometer, a stirrer, and a reflux condenser. While stirring under a nitrogen stream, the temperature was gradually raised to 220 °C, and the generated water was continuously removed. After the reaction, 117 g of maleic anhydride was further charged into the reaction vessel, and the reaction was completed at 120 °C. Thus, a biodegradable resin degradation accelerator A (white solid, number - average molecular weight: 1,700, acid value: 58, hydroxyl value: 65), which is a polyester with at least one end of the polyester of sebacic acid and 1,3 - propylene glycol sealed with maleic anhydride, was obtained.

[0076] (Synthesis Example 2: Synthesis of Biodegradable Resin Degradation Accelerator B) 490 g of sebacic acid, 200 g of ethylene glycol, and 0.04 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2-liter four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser. The temperature was gradually raised to 220°C while stirring under a nitrogen stream, and the generated water was continuously removed. After the reaction, 60 g of maleic anhydride was further charged into the reaction vessel, and the reaction was completed at 120°C. As a result, a biodegradable resin decomposition accelerator B (white solid, number average molecular weight: 1,200, acid value: 64, hydroxyl value: 100), which is a polyester in which at least one end of the polyester of sebacic acid and ethylene glycol is sealed with maleic anhydride, was obtained.

[0077] (Synthesis Example 3: Synthesis of biodegradable resin decomposition accelerator C) 490 g of sebacic acid and 150 g of ethylene glycol were charged into a 2-liter four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser. The temperature was gradually raised to 220°C while stirring under a nitrogen stream, and the generated water was continuously removed. As a result, a biodegradable resin decomposition accelerator C (white solid, number average molecular weight: 1,200, acid value: 47, hydroxyl value: 47), which is a polyester of sebacic acid and ethylene glycol and at least one end thereof is a carboxyl group, was obtained.

[0078] (Synthesis Example 4: Synthesis of biodegradable resin decomposition accelerator D) 1618 g of sebacic acid, 815 g of 1,2-propylene glycol, and 0.15 g of tetraisopropyl titanate as an esterification catalyst were charged into a 3-liter four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser. The temperature was gradually raised to 220°C while stirring under a nitrogen stream, and the generated water was continuously removed. After the reaction, 230 g of maleic anhydride was further charged, and the reaction was completed at 120°C. As a result, a biodegradable accelerator D (pale yellow liquid, number average molecular weight: 1,300, acid value: 55, hydroxyl value: 68), which is a polyester in which at least one end of the polyester of sebacic acid and 1,2-propylene glycol is sealed with maleic anhydride, was obtained.

[0079] (Synthesis Example 5: Synthesis of Biodegradable Resin Degradation Promoter E) 615 g of adipic acid, 460 g of 1,3-butanediol, 50 g of neopentyl glycol, and 0.10 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2-liter four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser, and the temperature was gradually raised to 220°C while stirring under a nitrogen stream, and the generated water was continuously removed. After the reaction, 45 g of maleic anhydride was further charged, and the reaction was completed at 120°C. As a result, a biodegradable resin degradation promoter E (pale yellow liquid, number average molecular weight: 1,000, acid value: 30, hydroxyl value: 120), which is a polyester in which at least one end of the polyester of adipic acid and 1,3-butanediol and neopentyl glycol is sealed with maleic anhydride, was obtained.

[0080] (Synthesis Comparative Example 1: Synthesis of Biodegradable Resin Degradation Promoter A’) 263 g of adipic acid, 280 g of diethylene glycol monomethyl ether, 253 g of benzyl alcohol, and 0.04 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2-liter four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser, and the temperature was gradually raised to 220°C while stirring under a nitrogen stream, and the generated water was continuously removed. After the reaction, the reaction mixture was distilled under reduced pressure at the same temperature to obtain a biodegradable resin degradation promoter A’ (pale yellow liquid, number average molecular weight: 600, acid value: 0.5, hydroxyl value: 0.8), which is an ester compound in which both ends of adipic acid are sealed with diethylene glycol monomethyl ether and benzyl alcohol.

[0081] (Examples 1-4 and Comparative Examples 1-2: Preparation and Evaluation of PBS Compositions) Biodegradable resin compositions were prepared by kneading the components shown in Table 1 at 120°C for 15 minutes using a mixer. The obtained biodegradable resin compositions were evaluated as follows. The results are shown in Table 1.

[0082] The polybutylene succinate used in Table 1 is "BioPBS FZ71PM" manufactured by PTT MCC Biochem Co., Ltd.

[0083] (Biodegradability test) The prepared biodegradable resin composition was dissolved in chloroform so that the non-volatile content became 7% by mass, and then the obtained chloroform solution was applied to a glass plate using an applicator (0.5 mm / wet). The glass plate with the coating film was left standing at room temperature overnight to dry the coating film. The dried coating film was cut into pieces of 2 cm × 2 cm to obtain test pieces.

[0084] A glass bottle was filled with soil (moisture 30 wt%) collected from a field in Ichihara City, Chiba Prefecture, and the test pieces were buried in this soil. The lid of the bottle was closed and the bottle was left standing in a constant temperature bath at 60°C for 4 weeks. The weight change of the test pieces before and after standing was measured, and the weight retention rate (weight of the test piece after standing / weight of the test piece before standing × 100) was calculated.

[0085] (Plasticization test) The obtained biodegradable resin composition was put into a melt indexer (「F-F01」manufactured by Toyo Seiki Seisaku-sho, Ltd., orifice inner diameter: 2.090 mm, cylinder temperature: 190°C), a load of 1,000 g was applied, and after preheating for 4 minutes, the melt flow rate was measured.

[0086] [Table 1]

[0087] From the results in Table 1, it can be seen that by adding a polyester having a carboxyl group at at least one end to the biodegradable resin, the decomposition of polybutylene succinate, which is a biodegradable resin, is promoted and a plasticizing effect can also be obtained.

[0088] (Examples 5 - 8 and Comparative Example 3: Preparation and evaluation of PLA composition) A biodegradable resin composition was prepared by kneading the components shown in Table 2 at 170°C for 15 minutes using a mixer. The obtained biodegradable resin composition was evaluated as follows. The results are shown in Table 2.

[0089] The polylactic acid used in Table 2 is "Luminy LX-175" manufactured by Total Corbion PLA Co., Ltd.

[0090] (Biodegradability test) The prepared biodegradable resin composition was dissolved in chloroform so that the non-volatile content became 7% by mass, and then the obtained chloroform solution was applied to a glass plate using an applicator (0.5 mm / wet). The glass plate with the coating film was left standing at 110°C for 1 hour to dry the coating film. The dried coating film was cut into 2 cm × 2 cm pieces to obtain test pieces.

[0091] A glass bottle was filled with soil collected from a field in Ichihara City, Chiba Prefecture (moisture 30 wt%), and the test piece was buried in this soil. The lid of the bottle was closed and left standing in a constant temperature bath at 60°C for 4 weeks. The change in the number average molecular weight of polylactic acid in the test piece before and after standing was measured, and the number average molecular weight retention rate (number average molecular weight of polylactic acid after standing / number average molecular weight of polylactic acid before standing × 100) was calculated. In addition, in the measurement of the number average molecular weight in this test, since polylactic acid does not dissolve in tetrahydrofuran, the measurement sample was dissolved in chloroform, and the measurement was carried out using "EcoSEC Data Analysis version 1.15" manufactured by Tosoh Corporation for data processing.

[0092] (Plasticization test) The obtained biodegradable resin composition was put into a melt indexer ("F-F01" manufactured by Toyo Seiki Co., Ltd., orifice inner diameter: 2.090 mm, cylinder temperature: 190°C), a load of 1,000 g was applied, and after preheating for 4 minutes, the melt flow rate was measured.

[0093]

Table 2

[0094] From the results in Table 2, it can be seen that by adding a polyester having a carboxyl group at at least one end to the biodegradable resin, the decomposition of polylactic acid, which is a biodegradable resin, is promoted, and a plasticizing effect can also be obtained.

[0095] (Example 9 and Comparative Example 4: Preparation and Evaluation of PBAT Composition) A biodegradable resin composition was prepared by kneading the components shown in Table 3 at 130 °C for 15 minutes using a mixer. The following evaluations were performed on the obtained biodegradable resin composition. The results are shown in Table 3.

[0096] The polybutylene adipate terephthalate used in Table 3 is "ecoflex" manufactured by BASF.

[0097] (Biodegradability Test) 30 g of soil (moisture 30 wt%) collected from a field in Ichihara City, Chiba Prefecture, and 30 mg of the biodegradable resin composition pulverized by a cryogenic mill ("JFC-300" manufactured by Nippon Kogaku Kogyo Co., Ltd.) were mixed, and the obtained mixture was filled into a glass container. After introducing 5 mL of 1 M sodium hydroxide solution as a carbon dioxide absorbent into the glass container, the glass container was sealed and left standing in a constant temperature bath at 30 °C. After 3 weeks, the unreacted sodium hydroxide was titrated with 0.1 M hydrochloric acid solution to calculate the amount of carbon dioxide generated in the container (amount of NaOH before the start of the test - amount of HCl dropped). The same operation as above was performed on the soil without the biodegradable resin composition to calculate the amount of CO2 generated, and the amount of CO2 generated by biodegradation (amount of CO2 generated (with biodegradable resin composition) - amount of CO2 generated (without biodegradable resin composition)) was calculated. Then, (amount of CO2 generated by biodegradation / amount of CO2 generated when the biodegradable resin composition is completely biodegraded (calculated value)) × 100 was evaluated as the biodegradation rate.

[0098] (Plasticization Test) The obtained biodegradable resin composition was put into a melt indexer ("F-F01" manufactured by Toyo Seiki Co., Ltd., orifice inner diameter: 2.090 mm, cylinder temperature: 190 °C), a load of 2,160 g was applied, and after preheating for 4 minutes, the melt flow rate was measured.

[0099]

Table 3

[0100] From the results in Table 3, it can be seen that by adding a polyester having a carboxyl group at at least one end to the biodegradable resin, the degradation of polybutylene adipate terephthalate, which is a biodegradable resin, is promoted, and a plasticizing effect can also be obtained.

[0101] (Examples 10 - 12 and Comparative Example 5: Preparation and Evaluation of PHBV Compositions) The components shown in Table 4 were allowed to stand at 80°C for 1 hour to allow the components to mix well with each other, and then were charged into a melt kneader ("Laboplast Mill" manufactured by Toyo Seiki Seisaku-sho, Ltd.), and extruded at a kneading temperature of 175°C to prepare a biodegradable resin composition. The following evaluations were performed on the obtained biodegradable resin composition. The results are shown in Table 4.

[0102] Note that poly(hydroxybutyrate-co-valerate) (PHBV) used in Table 4 was manufactured by Highchem Co., Ltd.

[0103] (Biodegradability Test) 30 g of soil (moisture content 30 wt%) collected from a field in Ichihara City, Chiba Prefecture and 30 mg of the biodegradable resin composition pulverized by a cryogenic mill ("JFC - 300" manufactured by Nippon Analytical Industry Co., Ltd.) were mixed, and the obtained mixture was filled into a glass container. After introducing 5 mL of 1M sodium hydroxide solution as a carbon dioxide absorbent into the glass container, the glass container was sealed and left in a constant temperature bath at 30°C. After 3 weeks, the unreacted sodium hydroxide was titrated with 0.1M hydrochloric acid solution to calculate the amount of carbon dioxide generated in the container (amount of NaOH before the start of the test - amount of HCl dropped). The same operation as above was also performed on the soil not containing the biodegradable resin composition to calculate the amount of CO2 generated, and the amount of CO2 generated by biodegradation (amount of CO2 generated (with biodegradable resin composition) - amount of CO2 generated (without biodegradable resin composition)) was calculated. Then, (amount of CO2 generated by biodegradation / amount of CO2 generated when the biodegradable resin composition is completely biodegraded (calculated value)) × 100 was evaluated as the biodegradation rate.

[0104] (Plasticization Test) The obtained biodegradable resin composition was put into a melt indexer (manufactured by Toyo Seiki Co., Ltd., "F-F01", orifice inner diameter: 2.090 mm, cylinder temperature: 190 °C), a load of 2,160 g was applied, and after preheating for 4 minutes, the melt flow rate was measured.

[0105]

Table 4

[0106] From the results in Table 4, it can be seen that by adding a polyester having a carboxyl group at at least one end to the biodegradable resin, the degradation of poly(hydroxybutyrate-co-valerate), which is a biodegradable resin, is promoted and a plasticizing effect can also be obtained.

Claims

1. A biodegradable resin, A polyester having a repeating unit represented by the following general formula (A) and a repeating unit represented by the following general formula (G), or a polyester having a repeating unit represented by the following general formula (L), a repeating unit represented by the following general formula (A), and a repeating unit represented by the following general formula (G), which is a biodegradable resin decomposition accelerator that is a polyester having a carboxyl group at at least one end, A molded article of a biodegradable resin composition containing the same. 【Chemical Formula 5】 (In the general formulas (A), (G), and (L), A is an aliphatic dibasic acid residue having 0 to 12 carbon atoms or an aromatic dibasic acid residue having 5 to 15 carbon atoms, G is an aliphatic diol residue having 2 to 12 carbon atoms, L is a hydroxycarboxylic acid residue having 2 to 18 carbon atoms.)

2. The molded article according to claim 1, which is used in a zooplankton breeding facility.

3. The molded article according to claim 1, which is used in a water treatment device.

4. The molded article according to claim 1, which is used in a foam.

5. The molded article according to claim 1, which is used as a drain material.

6. The molded article according to claim 1, which is used in a downhole tool member.

7. The molded article according to claim 1, which is used in a flak plug.

8. The molded article according to claim 1, which is used in a shell for percussion fireworks.

9. The molded article according to claim 1, which is used in a battery material.

10. The molded article according to claim 1, which is used for a capacitor.

11. The molded article according to claim 1, which is used for a sensor.

12. The molded article according to claim 1, which is used for a shape memory material.

13. The molded article according to claim 1, which is used for a biodegradable stent.

14. The molded article according to claim 1, which is used for a microbial carrier.

Images