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US-12624193-B2 - Biodegradable resin composition and molded product

US12624193B2US 12624193 B2US12624193 B2US 12624193B2US-12624193-B2

Abstract

Provided is a biodegradable resin composition that exhibits excellent biodegradability even in a molded product having a large thickness, has excellent mechanical properties, and is economically advantageous, and a molded product using the same. The molded product is provided using an inorganic substance powder-containing biodegradable resin composition including: a biodegradable resin and an inorganic substance powder in a mass ratio of 10:90 to 70:30, in which the biodegradable resin is a cellulose acetate-based resin and the inorganic substance powder is heavy calcium carbonate.

Inventors

  • Hiroshi Nakamura
  • Eiji Mizuno
  • Gouki SASAKAWA

Assignees

  • TBM CO., LTD.

Dates

Publication Date
20260512
Application Date
20201027
Priority Date
20200124

Claims (20)

  1. 1 . An inorganic substance powder-containing biodegradable resin composition comprising: a biodegradable resin and an inorganic substance powder in a mass ratio of 10:90 to 70:30, wherein the biodegradable resin is a cellulose acetate-based resin, and the inorganic substance powder is heavy calcium carbonate, which is a product produced by crushing and classifying natural calcium carbonate, having a roundness of 0.50 to 0.95, and the inorganic substance powder-containing biodegradable resin composition does not contain a thermoplastic resin other than the cellulose acetate-based resin, wherein the inorganic substance powder-containing biodegradable resin composition does not comprise a plasticizer.
  2. 2 . The inorganic substance powder-containing biodegradable resin composition according to claim 1 , wherein a degree of acetylation of the cellulose acetate-based resin is 50% to 65%.
  3. 3 . The inorganic substance powder-containing biodegradable resin composition according to claim 1 , wherein the inorganic substance powder is heavy calcium carbonate without surface treatment.
  4. 4 . The inorganic substance powder-containing biodegradable resin composition according to claim 1 , wherein an average particle diameter calculated from a measurement result of a specific surface area of particles of the heavy calcium carbonate by an air permeation method in accordance with JIS M-8511 is 0.7 μm or more and 6.0 μm or less.
  5. 5 . The inorganic substance powder-containing biodegradable resin composition according to claim 1 , wherein the inorganic substance powder-containing biodegradable resin composition is used for vacuum molding.
  6. 6 . The inorganic substance powder-containing biodegradable resin composition according to claim 1 , wherein the inorganic substance powder-containing biodegradable resin composition is used for inflation molding.
  7. 7 . A molded product comprising the inorganic substance powder-containing biodegradable resin composition according to claim 1 .
  8. 8 . A sheet for vacuum molding made by extrusion molding the inorganic substance powder-containing biodegradable resin composition according to claim 5 .
  9. 9 . A film made by inflation molding the inorganic substance powder-containing biodegradable resin composition according to claim 6 .
  10. 10 . A molded product made by vacuum molding the sheet for vacuum molding according to claim 8 .
  11. 11 . An injection-molded product comprising the inorganic substance powder-containing biodegradable resin composition according to claim 1 .
  12. 12 . The inorganic substance powder-containing biodegradable resin composition according to claim 2 , wherein the inorganic substance powder is heavy calcium carbonate without surface treatment.
  13. 13 . The inorganic substance powder-containing biodegradable resin composition according to claim 2 , wherein an average particle diameter calculated from a measurement result of a specific surface area of particles of the heavy calcium carbonate by an air permeation method in accordance with JIS M-8511 is 0.7 μm or more and 6.0 μm or less.
  14. 14 . An inorganic substance powder-containing biodegradable resin composition comprising: a biodegradable resin and an inorganic substance powder in a mass ratio of 10:90 to 70:30, wherein the biodegradable resin is a cellulose acetate-based resin, and the inorganic substance powder is heavy calcium carbonate, which is a product produced by crushing and classifying natural calcium carbonate, having a roundness of 0.50 to 0.95, and the inorganic substance powder-containing biodegradable resin composition does not contain polylactic acid and has a tensile strength of 38.9 to 43.8 MPa, wherein the inorganic substance powder-containing biodegradable resin composition does not comprise a plasticizer.
  15. 15 . The inorganic substance powder-containing biodegradable resin composition according to claim 1 , wherein the roundness of the heavy calcium carbonate is 0.50 to 0.55.
  16. 16 . The inorganic substance powder-containing biodegradable resin composition according to claim 2 , wherein the roundness of the heavy calcium carbonate is 0.50 to 0.55.
  17. 17 . The inorganic substance powder-containing biodegradable resin composition according to claim 14 , wherein the roundness of the heavy calcium carbonate is 0.50 to 0.55.
  18. 18 . The inorganic substance powder-containing biodegradable resin composition according to claim 1 , wherein the mass ratio of the biodegradable resin and the inorganic substance powder is 10:90 to 40:60.
  19. 19 . The inorganic substance powder-containing biodegradable resin composition according to claim 2 , wherein the mass ratio of the biodegradable resin and the inorganic substance powder is 10:90 to 40:60.
  20. 20 . The inorganic substance powder-containing biodegradable resin composition according to claim 14 , wherein the mass ratio of the biodegradable resin and the inorganic substance powder is 10:90 to 40:60.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This is the U.S. national stage of application No. PCT/JP2020/040308, filed on Oct. 27, 2020. Priority under 35 U.S.C. § 119 (a) and 35 U.S.C. § 365 (b) is claimed from Japanese Application No. 2020-010279, filed Jan. 24, 2020, the disclosure of which is also incorporated herein by reference. FIELD The present invention relates to a biodegradable resin composition and a molded product using the same. Specifically described, the present invention relates to a biodegradable resin composition and a molded product having excellent biodegradability under an environment and sufficient mechanical strength. BACKGROUND Biodegradable resins have attracted attention as environmentally friendly resins because the resins turn into substances that originally exist in nature due to actions such as hydrolysis under the environment and microbial metabolism, and are widely used and expected to be more widely used in the future. Conventionally, a cellulose acetate-based resin has been known as the biodegradable resin. The cellulose acetate-based resin has long been used as a fiber and film material and has attracted attention again as the biodegradable resin because the cellulose acetate-based resin can be hydrolyzed in water at a pH of 2 to 10 to lower its molecular weight and eventually decompose into carbon dioxide and water. For example, Patent Literature 1 has disclosed a biodegradable press-through package made of a bottom material including a biodegradable resin substrate/a metal layer and/or an organometallic compound layer and a lid material including a substrate of a biodegradable resin and an inorganic filler/a metal layer and/or an organometallic compound layer and has described the substrate for the lid material including 100 parts by weight of cellulose acetate and 25 parts by weight of talc. Patent Literature 2 has disclosed a coated paper for inkjet recording made by applying the composition of a biodegradable resin including a white pigment onto the surface of a sheet product of a recovered paper material and/or a non-wood pulp material and has described a cellulose acetate-based resin together with a polyhydroxyvalerate-butyrate copolymer and the like as the biodegradable resin. Patent Literature 3 has described flak-like cellulose acetate having 20 pieces/mm2 or less of bright spot foreign matters of 20 μm or more. In order to enhance the biodegradability of these cellulose acetate-based resins, various formulations also have been studied. For example, Patent Literature 4 has disclosed a composition including a polysaccharide ester, starch, and a plasticizer. In Examples, a composition including 38 parts by mass of cellulose acetate, 25 parts by mass of starch, 14 parts by mass of a plasticizer, 10 parts by mass of calcium carbonate, and the like has been described. Patent Literature 5 has disclosed a biodegradable resin composition including a biodegradable resin and a mannan degradation product. In Examples, a resin composition including polylactic acid, talc as a crystal nucleating agent, and galacto-manno-oligosaccharide in a weight ratio of 50:40:10 has been described. With respect to the spread of the products using the biodegradable resin, however, many problems still remain unsolved. For example, the cellulose acetate-based resin provides satisfactory biodegradability of molded products having a small thickness such as films. However, molded products having a large thickness require long period of time for biodegradation. In particular, the biodegradability is significantly inferior under a marine environment. Therefore, the cellulose acetate-based resin has a significant problem in practical use. In general, the biodegradable resins are expensive in price due to high production costs. This is also a significant problem in order to replace petrochemical-based plastics and to spread. The inventions described in Patent Literatures 4 and 5 aim to solve these problems. The above-described problems, however, have not yet been solved. In the case where starch and other components are added to the biodegradable resin, biodegradability is enhanced but mechanical properties such as strength and elongation are frequently deteriorated. Therefore, from the viewpoint of practicality, the blending amount of starch relative to the amount of the resin is limited and thus cost reduction is not so much achieved. The same problem may occur in the formulation of mannan degradation products. CITATION LIST Patent Literature Patent Literature 1: Japanese Patent Application Laid-open No. H9-216654Patent Literature 2: Japanese Patent Application Laid-open No. 2001-39014Patent Literature 3: Japanese Patent Application Laid-open No. 2010-196056Patent Literature 4: Published Japanese Translation of PCT International Publication for Patent Application No. 2002-523598Patent Literature 5: WO2001/42367 Pamphlet SUMMARY Technical Problem The present invention has been made in view of the abov