Method for molding biodegradable resin composition, and biodegradable resin molded body

Abstract

The present invention provides a method for molding a biodegradable resin composition which gives a highly flexible biodegradable resin molded article, and the biodegradable resin molded article. [Solution] A method for molding a biodegradable resin composition includes a crushing process in which the biodegradable resin composition is crushed, and a molding process in which the crushed product obtained through the crushing process is mixed with a plasticizer and then molded. A biodegradable resin molded product contains a biodegradable resin and a plasticizer, and the content of the plasticizer in the biodegradable resin molded product is 21 phr or more.

Description

[Technical field]

[0001] The present invention relates to a method for molding a biodegradable resin composition, and a biodegradable resin molded article. [Background technology]

[0002] Biodegradable resins have been attracting attention for many years as alternative materials to petroleum-derived plastics from the viewpoint of reducing environmental impact. In particular, biodegradable polyester is a biodegradable resin that is produced in large quantities, and its widespread use in various applications is being considered.

[0003] Patent Document 1 discloses a molded article of a resin composition containing a branched biodegradable polyester having a block structure including a random copolymer segment of lactide and caprolactone and a homopolymer segment of lactide, and having a trihydric or higher polyhydric alcohol bonded to an end of the block structure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-058335 A Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, there has been a demand for highly flexible biodegradable resin molded articles. The problem that the present invention aims to solve is to provide a method for molding a biodegradable resin composition that gives a highly flexible biodegradable resin molded article, and the biodegradable resin molded article. [Means for solving the problem]

[0006] The present inventors have conducted extensive research in light of the above problems and have found that a method for molding a biodegradable resin composition, which includes a grinding process in which a biodegradable resin composition is ground, and a molding process in which the ground product obtained through the grinding process is mixed with a plasticizer and then molded, can provide a biodegradable resin molded product with high flexibility. The present invention has been completed based on these findings.

[0007] The present invention provides a method for molding a biodegradable resin composition, comprising the steps of: Contains thermoplastic starch A pulverization process in which the biodegradable resin composition is pulverized, and a pulverized product obtained through the pulverization process. Ester-based The plasticizer is mixed and then molded in a molding process. the biodegradable resin contained in the biodegradable resin composition is polybutyl adipate terephthalate, and the content of the ester-based plasticizer per 100 parts by mass of the total of the mass of the polybutyl adipate terephthalate and the mass of the thermoplasticized starch is 21 parts by mass or more. Method for molding biodegradable resin composition 。 Effect of the Invention

[0010] The method for molding the biodegradable resin composition of the present invention provides a biodegradable resin molded article having high flexibility. The biodegradable resin molded article of the present invention is a biodegradable resin molded article having high flexibility. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will now be described in further detail. In addition, unless otherwise specified, a numerical range of "X to Y" represents a range from X to Y, including both ends. In addition, when a numerical range is indicated, the upper and lower limits can be appropriately combined, and the numerical range obtained by combining them is also considered to be disclosed.

[0012] The method for molding the biodegradable resin composition of the present invention includes a grinding process in which the biodegradable resin composition is ground, and a molding process in which the ground product obtained through the grinding process is kneaded with a plasticizer and then molded.

[0013] <Biodegradable resin> The biodegradable resin composition includes a biodegradable resin. The biodegradable resin preferably includes a biodegradable polyester. The biodegradable polyester is not limited to a specific biodegradable polyester. The biodegradable polyester preferably includes at least one selected from the group consisting of polylactic acid, polyhydroxyalkanoate, polybutylene succinate, cellulose acetate, polyvinyl alcohol, polyglycolic acid, polybutylene succinate-co-adipate, polybutylene adipate terephthalate, and polyethylene terephthalate succinate, more preferably at least one selected from the group consisting of polybutyl adipate terephthalate, polylactic acid, and polycaprolactone, and even more preferably at least one selected from the group consisting of polybutyl adipate terephthalate, polylactic acid, and polycaprolactone.

[0014] <Plasticizer> The biodegradable resin composition includes a plasticizer. The plasticizer is not limited to a specific plasticizer. The plasticizer preferably includes at least one selected from the group consisting of ester-based plasticizers such as phthalates, adipic acid esters, trimellitic acid esters, polyesters, sepoxidized vegetable oils, and epoxidized vegetable oils, and is more preferably an ester-based plasticizer. The ester-based plasticizer is commercially available. Examples of commercially available ester-based plasticizers include DAIFATTY-101 (registered trademark) manufactured by Daihachi Chemical Industry Co., Ltd., Monocizer PB-3A manufactured by DIC Corporation, Monocizer PB-10 manufactured by DIC Corporation, Monocizer W-83 manufactured by DIC Corporation, Biocizer manufactured by Riken Vitamin Co., Ltd., and Elecut manufactured by Takemoto Oil Co., Ltd.

[0015] The biodegradable resin composition may contain thermoplasticized starch. The starch used as the raw material of the thermoplasticized starch is not limited to a specific starch. Examples of the starch include corn starch, waxy corn starch, tapioca starch, rice starch, wheat starch, potato starch, sweet potato starch, mung bean starch, potato chestnut starch, kudzu starch, bracken starch, and sago starch. The starch may also be at least one type of starch that has been improved by breeding or genetic engineering techniques, such as the non-glucan, waxy, and high amylose varieties of the starches. The starch used in the present invention may be a processed starch, so long as the starch particle shape is maintained. The modified starch may be a modified starch obtained by subjecting unmodified raw starch to a chemical treatment such as oxidation, esterification, etherification, crosslinking, acid treatment, or alkali treatment, or a modified starch obtained by subjecting a physical treatment such as granulation, moist heat treatment, hot water treatment, bleaching, sterilization, oil processing, heat treatment, pressure treatment, decompression treatment, milling, powder collision treatment, friction treatment, pulverization, or extrusion. Alternatively, modified starch obtained by combining two or more of these treatments may also be used. Each of the chemical and physical treatments may be applied to starch that has been subjected to at least one of physical processing and enzyme treatment. Each of the chemical and physical treatments may also be applied to starch that has not yet been subjected to at least one of physical processing and enzyme treatment. An example of such modified starch is oxidized corn starch. In the present invention, at least one of the starches described above may be used.

[0016] The biodegradable resin composition may contain general additives added to resin compositions. Examples of the additives include compatibilizers, nucleating agents, UV absorbers, weathering agents, heat stabilizers, light stabilizers, binders, antiblocking agents, lubricants, neutralizing agents, crystallization accelerators, colorants, foaming agents, waterproofing agents, water repellents, antibacterial agents, antifogging agents, and impact resistance enhancing agents. The additives contain at least one of the additives, and are preferably at least one of the additives.

[0017] The biodegradable resin composition pulverized in the pulverization process includes raw resin, the plasticizer, and additives other than the plasticizer that are added as necessary. The biodegradable resin composition may be a dry blend or a pellet. The raw resin is commercially available. Examples of commercially available raw resins include Mater-bi manufactured by Novamont, Origo-Bi (registered trademark) ES01G manufactured by Novamont, Kaneka Biodegradable Polymer PHBH manufactured by Kaneka Corporation, BioPBS manufactured by Mitsubishi Chemical Corporation, Ecoflex manufactured by BASF, and Ecobio manufactured by BASF.

[0018] The particle size of the pulverized product obtained through the pulverization process is preferably 1000 μm or less, more preferably 500 μm or less. The pulverized product is sieved through a sieve with a specified mesh size to obtain the pulverized product having a particle size within a specified range.

[0019] The biodegradable resin composition obtained by kneading the ground pellets with the plasticizer may contain a larger amount of the plasticizer than the biodegradable resin composition obtained by kneading the pellets with the plasticizer. For example, the content of the plasticizer in the biodegradable resin molded product obtained through the molding process is 21 phr or more, preferably 25 phr or more, and more preferably 30 phr or more.

[0020] Therefore, the biodegradable resin molded article of the present invention has high flexibility and can be suitably used, for example, as at least one part selected from the group consisting of artificial baits, fishing tackles, and fishing equipment.

[0021] The molding method in the molding process is not limited to a specific molding method, and examples of the molding method include injection molding, extrusion molding, vacuum molding, blow molding, and bead foam molding. EXAMPLES

[0022] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these.

[0023] The raw material resins and plasticizers used in the examples and comparative examples are as follows. <Raw material resin> Polybutyl adipate terephthalate containing thermoplastic starch (Novamont Mate-Bi EF04P): Starch-containing PBAT Polybutyl adipate terephthalate (Oligo-BI ES01O, manufactured by Novamont): PBAT <Plasticizer> DAIFATTY-101 (registered trademark) manufactured by Daihachi Chemical Industry Co., Ltd.: DAIFATTY Monosizer PB-3A manufactured by DIC Corporation: PB-3A

[0024] [Comparative Example 1] 50 parts by mass of starch-containing PBAT, 50 parts by mass of PBAT, and 10 parts by mass of DAIFATTY were kneaded in a twin-screw extruder (TEX34αIII manufactured by The Japan Steel Works, Ltd.), and then 10 parts by mass of DAIFATTY was added to the kneaded mixture and kneaded in the twin-screw extruder to produce pellets. The pellets were injection molded.

[0025] [Comparative Example 2] 50 parts by mass of starch-containing PBAT, 50 parts by mass of PBAT, and 10 parts by mass of PB-3A were kneaded in the twin-screw extruder, and then 10 parts by mass of PB-3A was added to the resulting kneaded mixture and kneaded in the twin-screw extruder to produce pellets. The pellets were injection molded.

[0026] [Examples 1 and 2] 50 parts by mass of starch-containing PBAT and 50 parts by mass of PBAT were drive blended to obtain a blend, which was then pulverized, and the resulting powder was sieved through a 500 μm×500 μm mesh size sieve to obtain a pulverized product having a particle size of 500 μm or less. 100 parts by mass of the pulverized product and 33.3 parts by mass of DAIFATTY or PB-3A were kneaded in the twin-screw extruder to produce pellets. The pellets were injection molded.

[0027] [Examples 3 and 4] 50 parts by mass of starch-containing PBAT and 50 parts by mass of PBAT were dry blended, the blend obtained was pulverized, and the resulting powder was sieved through a 1000 μm×1000 μm mesh size to obtain a pulverized product with a particle size of 1000 μm or less. 100 parts by mass of the pulverized product and 33.3 parts by mass of DAIFATTY or PB-3A were kneaded in the twin-screw extruder to produce pellets. The pellets were injection molded.

[0028] [Table 1]

[0029] When mixing starch-containing PBAT and pellets containing PBAT with a plasticizer, it was not possible to mix more than 20 phr of the plasticizer. On the other hand, when mixing ground starch-containing PBAT and pellets containing PBAT with a plasticizer, it was possible to mix 21 phr or more of the plasticizer, and a molded product with high flexibility was obtained.

Claims

[Claim 1] A method for molding a biodegradable resin composition, comprising the steps of: a grinding process in which the biodegradable resin composition containing thermoplasticized starch is ground; and The pulverized product obtained through the pulverization process is kneaded with an ester-based plasticizer, and then molded in a molding process. the biodegradable resin contained in the biodegradable resin composition is polybutyl adipate terephthalate; a content of the ester-based plasticizer per 100 parts by mass of the total of the mass of the polybutyl adipate terephthalate and the mass of the thermoplasticized starch is 21 parts by mass or more;

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