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JP-7857234-B2 - Modified vinyl alcohol polymer, method for producing modified vinyl alcohol polymer, particles, aqueous solution, coating solution, coated product, molded article, release paper, dispersant, method for producing vinyl polymer, and mixture

JP7857234B2JP 7857234 B2JP7857234 B2JP 7857234B2JP-7857234-B2

Inventors

  • 新居 真輔

Assignees

  • 株式会社クラレ

Dates

Publication Date
20260512
Application Date
20211222
Priority Date
20201224

Claims (20)

  1. It has a structural unit represented by the following formula (1), The water-insoluble content is 1000 ppm or less. A modified vinyl alcohol polymer in which the content of the structural unit represented by the above formula (1) relative to all structural units containing silicon atoms is 90 mol% or more. [In formula (1), X, Y, and Z are each independently a C1-C20 alkyl group, a C2-C20 alkenyl group, a phenyl group, a benzyl group, a vinylphenyl group, a C1-C20 halogenated alkyl group, a halogenated phenyl group, a C1-C20 aminoalkyl group, a C1-C20 mercaptoalkyl group, a C2-C20 ureidoalkyl group, a C2-C8 isocyanatealkyl group, a C3-C20 group containing an epoxy group, a C3-C20 group containing an acrylamide group, a C4-C20 group containing a methacrylamide group, an acetoxy group, or a group represented by -( CH2 ) n -O- R1 (where R1 represents a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, a C1-C20 alkyl group, a C2-C20 alkenyl group, or a glycidyl group, and n represents an integer from 0 to 6).]
  2. The modified vinyl alcohol polymer according to claim 1, wherein the content of the structural unit represented by the above formula (1) is 0.01 mol% or more and less than 5 mol%.
  3. A method for producing a modified vinyl alcohol polymer, comprising the step of impregnating a solid vinyl alcohol polymer with a silane coupling agent.
  4. The method for producing a modified vinyl alcohol polymer according to claim 3, wherein, in the impregnation step described above, the vinyl alcohol polymer particles are impregnated by spraying them with a solution containing the silane coupling agent.
  5. A method for producing a modified vinyl alcohol polymer according to claim 3 or 4, wherein the silane coupling agent has a structure represented by the following formula (2). [In formula (2), R is an alkyl group having 1 to 8 carbon atoms, an acetyl group, or -( CH2 ) m -O- R2 (where R2 represents an alkyl group having 1 to 20 carbon atoms, and m represents an integer from 1 to 6). X, Y, and Z are each independently of a group represented by a C1-C20 alkyl group, a C2-C20 alkenyl group, a phenyl group, a benzyl group, a vinylphenyl group, a C1-C20 halogenated alkyl group, a halogenated phenyl group, a C1-C20 aminoalkyl group, a C1-C20 mercaptoalkyl group, a C2-C20 ureidoalkyl group, a C2-C8 isocyanatealkyl group, a C3-C20 group containing an epoxy group, a C3-C20 group containing an acrylamide group, a C4-C20 group containing a methacrylamide group, an acetoxy group, or a group represented by -( CH2 ) n -O- R1 (where R1 represents a C1-C20 alkyl group, a C2-C20 alkenyl group, an acryloyl group, a methacryloyl group, or a glycidyl group, and n represents an integer from 0 to 6).
  6. A method for producing a modified vinyl alcohol polymer according to claim 3, 4, or 5, further comprising the step of heat-treating the vinyl alcohol polymer impregnated with the silane coupling agent obtained in the above impregnation step.
  7. Particles containing the modified vinyl alcohol polymer described in claim 1 or 2.
  8. The particle according to claim 7, wherein the dispersion degree A of silicon atoms is 0.2 or greater and less than 1.
  9. An aqueous solution containing the modified vinyl alcohol polymer described in claim 1 or 2.
  10. It contains a modified vinyl alcohol polymer having a structural unit represented by the following formula (1), A coating solution in which the insoluble portion of the above-mentioned modified vinyl alcohol polymer is 1000 ppm or less, and the content of the structural unit represented by formula (1) relative to all structural units containing silicon atoms in the above-mentioned modified vinyl alcohol polymer is 90 mol% or more . [In formula (1), X, Y, and Z are each independently a C1-C20 alkyl group, a C2-C20 alkenyl group, a phenyl group, a benzyl group, a vinylphenyl group, a C1-C20 halogenated alkyl group, a halogenated phenyl group, a C1-C20 aminoalkyl group, a C1-C20 mercaptoalkyl group, a C2-C20 ureidoalkyl group, a C2-C8 isocyanatealkyl group, a C3-C20 group containing an epoxy group, a C3-C20 group containing an acrylamide group, a C4-C20 group containing a methacrylamide group, an acetoxy group, or a group represented by -( CH2 ) n -O- R1 (where R1 represents a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, a C1-C20 alkyl group, a C2-C20 alkenyl group, or a glycidyl group, and n represents an integer from 0 to 6).]
  11. The coating solution according to claim 10, wherein the content of the structural unit represented by formula (1) in the modified vinyl alcohol polymer is 0.01 mol% or more and less than 5 mol%.
  12. The coating liquid according to claim 10 or 11 , wherein the viscosity-average degree of polymerization of the modified vinyl alcohol polymer is 500 or more and 5000 or less, and the degree of saponification is 70 mol% or more and 99.9 mol% or less.
  13. A coated article obtained by applying the coating liquid according to any one of claims 10 to 12 to a substrate.
  14. The system comprises a base material, a silicone sealing layer, and a release layer. The above silicone sealing layer contains a modified vinyl alcohol polymer having a structural unit represented by the following formula (1'), Release paper having a content of 90 mol% or more of the structural unit represented by the above formula (1 ' ) relative to all structural units containing silicon atoms. [In formula (1'), X, Y, and Z are each independently a C1-C20 alkyl group, a C2-C20 alkenyl group, a phenyl group, a benzyl group, a vinylphenyl group, a C1-C20 halogenated alkyl group, a halogenated phenyl group, a C1-C20 aminoalkyl group, a C1-C20 mercaptoalkyl group, a C2-C20 ureidoalkyl group, a C2-C8 isocyanate alkyl group, a C3-C20 group containing an epoxy group, a C3-C20 group containing an acrylamide group, a C4-C20 group containing a methacrylamide group, an acetoxy group, or -( CH2 ) n -O- R1 (R 1 represents a hydrogen atom, alkali metal atom, alkaline earth metal atom, C1-C20 alkyl group, C2-C20 alkenyl group, acryloyl group, methacryloyl group, glycidyl group, or bond, and n represents an integer from 0 to 6.
  15. The release paper according to claim 14 , wherein the release layer contains addition-type silicone and platinum, and the content of platinum relative to 100 parts by mass of the addition-type silicone is 0.001 to 0.05 parts by mass.
  16. The modified vinyl alcohol polymer having a structural unit represented by the following formula (1) comprises A dispersant wherein the content of the structural unit represented by formula (1) above is 90 mol% or more relative to all structural units containing silicon atoms in the modified vinyl alcohol polymer. [In formula (1), X, Y, and Z are each independently a C1-C20 alkyl group, a C2-C20 alkenyl group, a phenyl group, a benzyl group, a vinylphenyl group, a C1-C20 halogenated alkyl group, a halogenated phenyl group, a C1-C20 aminoalkyl group, a C1-C20 mercaptoalkyl group, a C2-C20 ureidoalkyl group, a C2-C8 isocyanatealkyl group, a C3-C20 group containing an epoxy group, a C3-C20 group containing an acrylamide group, a C4-C20 group containing a methacrylamide group, an acetoxy group, or a group represented by -( CH2 ) n -O- R1 (where R1 represents a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, a C1-C20 alkyl group, a C2-C20 alkenyl group, an acryloyl group, a methacryloyl group, or a glycidyl group, and n represents an integer from 0 to 6). ]
  17. The dispersant according to claim 16 , wherein the content of the structural unit represented by formula (1) in the modified vinyl alcohol polymer is 0.01 mol% or more and less than 5 mol%.
  18. The dispersant according to claim 16 or 17 , wherein the viscosity-average degree of polymerization of the modified vinyl alcohol polymer is 500 or more and 1500 or less, and the degree of saponification is 60 mol% or more and 90 mol% or less.
  19. The dispersant according to any one of claims 16 to 18 , wherein the water-insoluble content of the modified vinyl alcohol polymer is 1000 ppm or less.
  20. A dispersant according to any one of claims 16 to 19 , for use in suspension polymerization.

Description

This disclosure relates to modified vinyl alcohol polymers, methods for producing modified vinyl alcohol polymers, polymer particles, aqueous solutions, coating solutions, coated products, molded articles, release paper, dispersants, methods for producing vinyl polymers, and mixtures. Vinyl alcohol polymers (hereinafter sometimes abbreviated as "PVA") are water-soluble and are used in a variety of applications, such as synthetic fiber raw materials, film raw materials, emulsifiers and dispersants, and adhesives. PVA is usually obtained by saponifying vinyl ester polymers, which are typically produced by polymerizing vinyl ester monomers. It is known that modified vinyl ester polymers, obtained by copolymerizing vinyl ester monomers with monomers having various functional groups, can be saponified to obtain modified PVA with special functions. On the other hand, various "post-modification" methods have been reported in which reactants having various functional groups are reacted with saponified PVA to introduce functional groups derived from the reactants into the PVA. For example, there are examples of using dicarboxylic acid as a modifying agent (Patent Document 1), and post-modification is being utilized as a useful technique for producing modified PVA. Other reported products include anti-fogging compositions (Patent Document 2) obtained by mixing PVA or its derivatives with a silane coupling agent, resin compositions (Patent Document 3), and fiber treatment agents (Patent Document 4). Furthermore, Patent Document 5 discloses a method for obtaining modified PVA by reacting PVA with a specific silane coupling agent. However, the above-mentioned documents 1 to 5 do not disclose a modified PVA that has a polymer structure in which a silane coupling agent is introduced into PVA, yet is easier to handle and has a wider range of applications. For example, when using modified PVA with low water solubility in coating liquids, dispersants for suspension polymerization, etc., it may take time to dissolve sufficiently, or undissolved components may have undesirable effects. Also, in Patent Document 5, the reaction between PVA and a specific silane coupling agent is carried out in an aqueous solution, and the modified PVA is obtained in solution form. Such a solution-type modified PVA is expected to have improvements in terms of handling, storage, and transportability. Furthermore, when solution-type modified PVA is made into particulate matter by drying, etc., crosslinking reactions proceed during the drying process, and water solubility tends to decrease. Furthermore, PVA is used in the paper industry as a paper strength enhancer, a dispersant for fluorescent white pigments, and a binder for inorganic materials (calcium carbonate, clay, silica, etc.). Because PVA has excellent film-forming properties, coating paper with it can impart barrier properties against gases and oil resistance. Paper coated with PVA is sometimes used as barrier paper, and a typical example of barrier paper is release paper base paper. Release paper base paper is usually manufactured by coating the surface of a cellulose substrate with PVA. Then, a release layer (silicone layer) is formed on the surface of this release paper base paper to obtain release paper. In release paper, PVA plays the role of a sealant that suppresses the penetration of expensive silicone or platinum into the substrate. Recently, in addition to this sealant property, there has been a demand for release paper base paper that can accelerate the hardening of the silicone in the release layer and improve the adhesion between the PVA layer and the silicone layer. Patent document 6 describes a release paper base coated with PVA having silyl groups that satisfy specific conditions. Patent document 7 describes PVA in which double bonds have been introduced to the side chains by an acetalization reaction. However, neither document 6 nor 7 discloses a coating liquid that exhibits excellent silicone curability and adhesion to the substrate. Furthermore, PVA is widely used as a dispersant, for example, as a dispersion stabilizer for suspension polymerization and emulsion polymerization of vinyl compounds. It is particularly useful as a dispersion stabilizer when using suspension polymerization of vinyl chloride. The resulting polyvinyl chloride resin (hereinafter sometimes abbreviated as "PVC resin") has excellent chemical resistance and electrical insulation properties, as well as excellent processability, and can be made both hard and soft, making it widely used as a molding material for various applications. PVC resin is generally manufactured on an industrial scale by suspension polymerization, in which vinyl chloride monomer is polymerized in an aqueous medium in the presence of a dispersion stabilizer using an oil-soluble polymerization initiator. PVA is widely used as a dispersion stabilizer in the polymerization of vinyl chloride, and it has been proposed to use PVA havi