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CN-121986202-A - Transparentizing agent, method for producing same, transparentizing paper, and method for producing same

CN121986202ACN 121986202 ACN121986202 ACN 121986202ACN-121986202-A

Abstract

The invention provides a transparentizing agent which uses biological raw materials and can obtain transparentizing paper with excellent transparency and time stability. The present invention provides a transparentizing agent comprising a polyester resin component which is a reaction product of raw material components comprising (A) rosin, (B) polycarboxylic acid, (C) polyol and (D) aliphatic monocarboxylic acid, wherein the acid value of the polyester resin component is 100mgKOH/g or less, the weight average molecular weight of the polyester resin component is 100 ten thousand or less, and the refractive index of the polyester resin component is 1.40 or more and 1.60 or less.

Inventors

  • NAKAMURA RYOTA
  • UNIV.
  • NAKATA TOMOHIKO
  • ASAYAMA YOSHIYUKI

Assignees

  • 王子控股株式会社
  • 哈利玛化成株式会社

Dates

Publication Date
20260505
Application Date
20241010
Priority Date
20231012

Claims (12)

  1. 1. A transparentizing agent, wherein, The transparentizing agent comprises a polyester resin component which is a reaction product of raw material components comprising (A) rosin, (B) polycarboxylic acid, (C) polyol and (D) aliphatic monocarboxylic acid, wherein the acid value of the polyester resin component is 100mgKOH/g or less, the weight average molecular weight of the polyester resin component is 100 ten thousand or less, and the refractive index of the polyester resin component is 1.40 or more and 1.60 or less.
  2. 2. The transparentizing agent according to claim 1, wherein, The iodine value of the polyester resin component is more than 10g/100g and less than 140g/100 g.
  3. 3. A process for producing a transparentizing agent, wherein, A polyester resin component having an acid value of 100mgKOH/g or less, a weight average molecular weight of 100 ten thousand or less, and a refractive index of 1.40 or more and 1.60 or less is obtained by reacting raw material components containing (A) rosins, (B) a polycarboxylic acid, (C) a polyol, and (D) an aliphatic monocarboxylic acid.
  4. 4. The method for producing a transparentizing agent according to claim 3, wherein, The iodine value of the polyester resin component is more than 10g/100g and less than 140g/100 g.
  5. 5. The method for producing a transparentizing agent according to claim 3 or 4, wherein, The (B) polycarboxylic acid comprises an alpha, beta-unsaturated dicarboxylic acid, In obtaining the polyester resin component, the rosin (a) is reacted with the α, β -unsaturated dicarboxylic acid to obtain a first product, and the first product, the (C) polyol, and the (D) aliphatic monocarboxylic acid are reacted.
  6. 6. The method for producing a transparentizing agent according to claim 3 or 4, wherein, The (B) polycarboxylic acid comprises an alpha, beta-unsaturated dicarboxylic acid, In the case of obtaining the polyester resin component, the rosin (a) is reacted with the α, β -unsaturated dicarboxylic acid to obtain a first product, the polyol (C) is modified with the fat or oil having the aliphatic monocarboxylic acid (D) as a constituent fatty acid to obtain a modified product, and the first product is reacted with the modified product.
  7. 7. A transparentizing paper, wherein, A transparentizing agent is contained in at least the inside of the paper base material, The transparentizing agent comprises a polyester resin component which is a reaction product of raw material components comprising (A) rosin, (B) polycarboxylic acid, (C) polyol and (D) aliphatic monocarboxylic acid, wherein the acid value of the polyester resin component is 100mgKOH/g or less, the weight average molecular weight of the polyester resin component is 100 ten thousand or less, and the refractive index of the polyester resin component is 1.40 or more and 1.60 or less.
  8. 8. The transparentizing paper according to claim 7, wherein, The iodine value of the polyester resin component is more than 10g/100g and less than 140g/100 g.
  9. 9. The transparentizing paper according to claim 7 or 8, wherein, The paper substrate comprises conifer chemical pulp and hardwood chemical pulp.
  10. 10. A method for producing a transparentizing paper, comprising the steps of coating or impregnating a paper substrate with a liquid composition comprising a transparentizing agent and a liquid medium, and drying the coated or impregnated paper substrate, The transparentizing agent comprises a polyester resin component which is a reaction product of raw material components comprising (A) rosin, (B) polycarboxylic acid, (C) polyol and (D) aliphatic monocarboxylic acid, wherein the acid value of the polyester resin component is 100mgKOH/g or less, the weight average molecular weight of the polyester resin component is 100 ten thousand or less, and the refractive index of the polyester resin component is 1.40 or more and 1.60 or less.
  11. 11. The method for producing a transparentized paper as claimed in claim 10, wherein, The iodine value of the polyester resin component is more than 10g/100g and less than 140g/100 g.
  12. 12. The method for producing a transparentized paper as claimed in claim 10 or 11, wherein, The paper substrate comprises conifer chemical pulp and hardwood chemical pulp.

Description

Transparentizing agent, method for producing same, transparentizing paper, and method for producing same Technical Field The present invention relates to a transparentizing agent and a method for producing the same, and a transparentizing paper and a method for producing the same. The present application claims priority based on 2023, 10 and 12 in japanese patent application No. 2023-176832, which is incorporated herein by reference. Background As a method for producing a paper having high transparency, there are generally a method of papermaking using pulp fibers having an increased degree of beating, a method of impregnating spaces between fibers of a base paper subjected to papermaking with a resin or the like, for example. A method of papermaking using pulp fibers with an improved freeness is used for the production of glass paper, tracing paper, and the like. Paper made by papermaking using pulp fibers with an improved freeness is used as packaging paper for window parts of envelopes and the like. However, such paper is often difficult to apply to applications such as packaging bags requiring strength due to the grinding and cutting of pulp fibers caused by high beating. On the other hand, a method of impregnating a space between fibers of a base paper made of paper with a resin or the like is used for manufacturing oiled paper, coated paper, or the like. For example, patent document 1 proposes a technique of obtaining a transparent paper by hot-melting, coating or impregnating a base paper with a transparentizing agent containing a resin and paraffin wax. Patent document 2 proposes a technique of obtaining a transparent paper by applying or impregnating a paper with a composition containing a liquid diene polymer and irradiating the paper with ultraviolet rays. Patent document 3 proposes a technique of applying a rosin-based aqueous transparentizing agent to a part of a base paper and heating the applied product to obtain a windowed package bag. Patent document 4 proposes a technique of printing a transparentizing agent that is impregnated with vegetable oil as a main component on a specific surface of a part of opaque paper, and forming an oil layer protective film on both surfaces thereof to make the opaque paper transparent. Prior art literature Patent literature Patent document 1 Japanese patent laid-open No. 61-132698 Patent document 2 Japanese patent laid-open No. 61-132699 Patent document 3 Japanese patent application laid-open No. 2011-63286 Patent document 4 Japanese patent laid-open No. 62-15395 Disclosure of Invention Problems to be solved by the invention In recent years, as a shift to sustainable and recyclable materials, the replacement of paper from plastic films is being studied. For example, paper replacement is also being performed in the field of packaging materials. It is considered that if transparency of the plastic film can be imparted to paper, the application is further expanded. In the techniques of patent documents 1 to 4, the transparency of the translucent region impregnated with the transparentizing agent can be improved by impregnating the voids between cellulose fibers of the paper with the transparentizing agent. However, the paraffin wax used in patent document 1 is a mixture of solid hydrocarbons produced from petroleum, and does not use a bio-derived raw material. The liquid diene polymer used in patent document 2 is also a petroleum-derived resin, and does not use a bio-derived raw material. The rosin-based aqueous transparentizing agent used in patent document 3 cannot obtain sufficient transparency. In patent document 4, an oil layer protection layer is required to prevent the impregnated vegetable oil from leaching out to the outside. In the case where the oil layer protective layer is not provided, the vegetable oil is leached out with time or dried to cause cloudiness of paper. The purpose of the present invention is to provide a transparentizing agent that uses a bio-derived raw material and that has excellent transparency and time-dependent stability, a method for producing the same, and a transparentizing paper that uses a bio-derived raw material and that has excellent transparency and time-dependent stability, and a method for producing the same. Means for solving the problems The inventors have studied a transparentizing agent using a rosin and an aliphatic carboxylic acid in combination. The rosin and the aliphatic carboxylic acid are substances showing values close to the refractive index of the cellulose pulp, respectively, and by using the above substances in combination, the refractive index of the cellulose pulp is closer than the refractive index of the cellulose pulp. However, in this state, as in patent document 4, the aliphatic carboxylic acid is leached or dried to cause cloudiness of paper. Therefore, the present inventors have further studied and found that the above problems can be solved by introducing a rosin and an aliphatic carboxylic a