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EP-4737491-A1 - VINYL CHLORIDE-BASED RESIN PASTE FOR SYNTHETIC LEATHER

EP4737491A1EP 4737491 A1EP4737491 A1EP 4737491A1EP-4737491-A1

Abstract

Provided is a polyvinyl chloride paste resin for synthetic leather, which is capable of providing synthetic leather with excellent flexibility and touch. The polyvinyl chloride paste resin is a vinyl chloride-vinyl acetate copolymer paste resin having a vinyl acetate residue unit content of 3 to 15 wt% and an average polymerization degree of 900 to 2,200. The synthetic leather contains such a polyvinyl chloride paste resin as a constituent material of a skin layer and/or a foam layer.

Inventors

  • WATANABE, KAZUNORI
  • YAHAGI, Yuta
  • BINGO, Shota

Assignees

  • Tosoh Corporation

Dates

Publication Date
20260506
Application Date
20240531

Claims (8)

  1. A polyvinyl chloride paste resin for synthetic leather, which is a vinyl chloride-vinyl acetate copolymer paste resin having a vinyl acetate residue unit content of 3 to 15 wt% and an average polymerization degree of 900 to 2,200.
  2. The polyvinyl chloride paste resin for synthetic leather according to Claim 1, wherein: the vinyl acetate residue unit content shows a continuous distribution with a single local maximum and a mode of 1 to 30 wt%; and a primary particle size of the paste resin at a maximum peak of cumulative weight frequency is 0.1 to 5 µm.
  3. Synthetic leather containing a vinyl chloride-vinyl acetate copolymer paste resin having a vinyl acetate residue unit content of 3 to 15 wt% and an average polymerization degree of 900 to 2,200.
  4. The synthetic leather according to Claim 3, comprising at least a skin layer, a foam layer and a base fabric, wherein the skin layer and/or the foam layer contains the vinyl chloride-vinyl acetate copolymer paste resin having a vinyl acetate residue unit content of 3 to 15 wt% and an average polymerization degree of 900 to 2,200.
  5. The synthetic leather according to Claim 4, wherein the skin layer contains 40 to 100 parts by weight of a plasticizer per 100 parts by weight of the vinyl chloride-vinyl acetate copolymer paste resin having a vinyl acetate residue unit content of 3 to 15 wt% and an average polymerization degree of 900 to 2,200.
  6. The synthetic leather according to Claim 4, wherein the foam layer contains 50 to 150 parts by weight of a plasticizer per 100 parts by weight of the vinyl chloride-vinyl acetate copolymer paste resin having a vinyl acetate residue unit content of 3 to 15 wt% and an average polymerization degree of 900 to 2,200.
  7. The synthetic leather according to Claim 5 or 6, wherein the plasticizer is at least one type selected from the group consisting of diisononyl phthalate, bis(2-ethylhexyl) terephthalate, diisodecyl phthalate, dibutyl phthalate, (2-ethylhexyl) adipate, diisononyl adipate, tri(2-ethylhexyl) trimellitate and triisodecyl trimellitate.
  8. A method for producing synthetic leather, comprising laminating a skin layer, a foam layer and a base fabric, wherein the skin layer and the foam layer are formed by paste processing in which a polyvinyl chloride paste sol for formation of the skin layer and/or a polyvinyl chloride paste sol for formation of the foam layer contains a vinyl chloride-vinyl acetate copolymer paste resin having a vinyl acetate residue unit content of 3 to 15 wt% and an average polymerization degree of 900 to 2,200 and a plasticizer.

Description

TECHNICAL FIELD The present invention relates to a polyvinyl chloride paste resin having properties suitable for synthetic leather, and more particularly relates to a polyvinyl chloride paste resin capable of providing synthetic leather with excellent flexibility and touch by having a specific amount of vinyl acetate residue unit and a specific average polymerization degree and to synthetic leather containing such a polyvinyl chloride paste resin. BACKGROUND ART Polyvinyl chloride paste resins (hereinafter sometimes abbreviated as paste PVC) are commonly used for various formed products such as wallpaper, tile carpets, gloves and the like by kneading paste PVC with plasticizers, fillers, stabilizers or other ingredients and forming the thus-prepared polyvinyl chloride paste sols (hereinafter sometimes abbreviated as PVC paste sols) by various forming processes. Furthermore, synthetic leather made from polyvinyl chloride with high mechanical strength and excellent abrasion resistance, chemical resistance and oil resistance has been proposed for applications in a wide range of fields including automotive interiors, furniture, bags and pouches, footwear, clothing and stationery etc. (see, for example, Patent Document 1). The touch of such synthetic leather can be improved with the addition of a plasticizer. Depending on the amount of the plasticizer added, however, there are seen cases where the plasticizer not only imparts flexibility to the synthetic leather but also affects the touch of the synthetic leather to cause a problem of stickiness or the like. To cope with this problem, the use of a specific plasticizer has been proposed (see, for example, Patent Document 2). PRIOR ART DOCUMENTS PATENT DOCUMENTS Patent Document 1: JP-A-H6-116875Patent Document 2: JP-A-H6-2281 DISCLOSURE OF INVENTION TECHNICAL PROBLEM However, the proposals of Patent Documents 1 and 2 are directed to synthetic leather and compositions thereof and give no consideration to paste PVC for synthetic leather. The consideration of plasticizers alone is limited in effectiveness. It is accordingly an object of the present invention to provide paste PVC suitable for synthetic leather, which is capable of providing synthetic leather with excellent flexibility and touch, and to provide synthetic leather containing such paste PVC. SOLUTION TO PROBLEM As a result of extensive studies made on the above problem, the present inventors have found that a vinyl chloride-vinyl acetate copolymer paste resin containing a specific amount of vinyl acetate residue unit and having a specific average polymerization degree can be used as paste PVC suitable for providing synthetic leather with excellent flexibility and touch, and thus have accomplished the present invention. That is, the present invention includes the following aspects [1] to [8]. [1] A polyvinyl chloride paste resin for synthetic leather, which is a vinyl chloride-vinyl acetate copolymer paste resin having a vinyl acetate residue unit content of 3 to 15 wt% and an average polymerization degree of 900 to 2,200.[2] The polyvinyl chloride paste resin for synthetic leather according to [1], wherein: the vinyl acetate residue unit content shows a continuous distribution with a single local maximum and a mode of 1 to 30 wt%; and a primary particle size of the paste resin at a maximum peak of cumulative weight frequency is 0.1 to 5 µm.[3] Synthetic leather containing a vinyl chloride-vinyl acetate copolymer paste resin having a vinyl acetate residue unit content of 3 to 15 wt% and an average polymerization degree of 900 to 2,200.[4] The synthetic leather according to [3], comprising at least a skin layer, a foam layer and a base fabric, wherein the skin layer and/or the foam layer contains the vinyl chloride-vinyl acetate copolymer paste resin having a vinyl acetate residue unit content of 3 to 15 wt% and an average polymerization degree of 900 to 2,200.[5] The synthetic leather according to [4], wherein the skin layer contains 40 to 100 parts by weight of a plasticizer per 100 parts by weight of the vinyl chloride-vinyl acetate copolymer paste resin having a vinyl acetate residue unit content of 3 to 15 wt% and an average polymerization degree of 900 to 2,200.[6] The synthetic leather according to [4] or [5], wherein the foam layer contains 50 to 150 parts by weight of a plasticizer per 100 parts by weight of the vinyl chloride-vinyl acetate copolymer paste resin having a vinyl acetate residue unit content of 3 to 15 wt% and an average polymerization degree of 900 to 2,200.[7] The synthetic leather according to [5] or [6], wherein the plasticizer is at least one type selected from the group consisting of diisononyl phthalate, bis(2-ethylhexyl) terephthalate, diisodecyl phthalate, dibutyl phthalate, (2-ethylhexyl) adipate, diisononyl adipate, tri(2-ethylhexyl) trimellitate and triisodecyl trimellitate.[8] A method for producing synthetic leather, comprising laminating a skin layer, a foam layer and a