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EP-4019249-B1 - RESIN LAYERED BODY

EP4019249B1EP 4019249 B1EP4019249 B1EP 4019249B1EP-4019249-B1

Inventors

  • NAKAMURA, JIN
  • MIYABE, Takanori
  • ODA, TAKAFUMI

Dates

Publication Date
20260506
Application Date
20200806

Claims (14)

  1. A resin laminate comprising: a polyester layer containing a polyester resin (A); and a mixed resin layer containing a polyamide resin (B) and a polyester resin (C); wherein the polyamide resin (B) includes a constituent unit derived from a diamine and a constituent unit derived from a dicarboxylic acid, 70 mol% or greater of the constituent unit derived from a diamine being a constituent unit derived from xylylenediamine, and 70 mol% or greater of the constituent unit derived from a dicarboxylic acid being a constituent unit derived from an α,ω-linear aliphatic dicarboxylic acid having from 4 to 20 carbons; a content of the polyamide resin (B) in the mixed resin layer is not less than 70 mass% based on the mixed resin layer; and the resin laminate is irradiated with an electron beam, and a radical concentration in the mixed resin layer is 1 × 10 -12 mol/g to 2000000 × 10 -12 mol/g wherein the radical concentration is measured as set out in the specification.
  2. The resin laminate according to claim 1, wherein a mass ratio [(B)/(C)] of the polyamide resin (B) to the polyester resin (C) in the mixed resin layer is from 70/30 to 95/5.
  3. The resin laminate according to claim 1 or 2, wherein the polyester resin (A) includes a constituent unit derived from a dicarboxylic acid and a constituent unit derived from a diol, 90 mol% or greater of the constituent unit derived from a dicarboxylic acid being a constituent unit derived from terephthalic acid, and 90 mol% or greater of the constituent unit derived from a diol being a constituent unit derived from ethylene glycol.
  4. The resin laminate according to any one of claims 1 to 3, wherein the polyester resin (C) includes a constituent unit derived from a dicarboxylic acid and a constituent unit derived from a diol, 90 mol% or greater of the constituent unit derived from a dicarboxylic acid being a constituent unit derived from terephthalic acid, and 90 mol% or greater of the constituent unit derived from a diol being a constituent unit derived from ethylene glycol.
  5. The resin laminate according to any one of claims 1 to 4, wherein the polyamide resin (B) includes a constituent unit derived from a diamine and a constituent unit derived from a dicarboxylic acid, 80 mol% or greater of the constituent unit derived from a diamine being a constituent unit derived from xylylenediamine, and 80 mol% or greater of the constituent unit derived from a dicarboxylic acid being a constituent unit derived from adipic acid.
  6. The resin laminate according to any one of claims 1 to 5, wherein the resin laminate is a three-layer structure laminated in the order of polyester layer/mixed resin layer/polyester layer, or a five-layer structure laminated in the order of polyester layer/mixed resin layer/polyester layer/mixed resin layer/polyester layer.
  7. The resin laminate according to any one of claims 1 to 6, wherein the radical concentration in the mixed resin layer is from 10 × 10 -12 to 2000000 × 10 -12 mol/g.
  8. A multilayered film comprising the resin laminate described in any one of claims 1 to 7.
  9. A multilayered container comprising the resin laminate described in any one of claims 1 to 7.
  10. The multilayered container according to claim 9, comprising at least one polyester layer at an inner side relative to the mixed resin layer and another at least one polyester layer at an outer side relative to the mixed resin layer.
  11. The multilayered container according to claim 9 or 10, wherein an overall thickness of the multilayered container is from 50 to 500 µm.
  12. The multilayered container according to any one of claims 9 to 11, wherein when the overall thickness is defined as 100%, a location of the mixed resin layer starts at a position from 5 to 35% from an inner surface, and a thickness of the mixed resin layer is from 1 to 15%.
  13. A method for producing a multilayered container satisfying (1) to (3), the method comprising steps 1 and 2: 1: forming a multilayered container molded body including at least one polyester layer at an inner side relative to a mixed resin layer and another at least one polyester layer at an outer side relative to a mixed resin layer; and 2: irradiating the multilayered container molded body with an electron beam; wherein (1) the multilayered container includes a polyester layer containing a polyester resin (A), and a mixed resin layer containing a polyamide resin (B) and a polyester resin (C), and (2) the polyamide resin (B) includes a constituent unit derived from a diamine and a constituent unit derived from a dicarboxylic acid, 70 mol% or greater of the constituent derived from a diamine being a constituent unit derived from xylylenediamine, and 70 mol% or greater of the constituent unit derived from a dicarboxylic acid being a constituent unit derived from an α,ω-linear aliphatic dicarboxylic acid having from 4 to 20 carbons, a content of the polyamide resin (B) in the mixed resin layer is not less than 70 mass% based on the mixed resin layer, and (3) a radical concentration in the mixed resin layer is 1 × 10 -12 mol/g to 2000000 × 10 -12 mol/g wherein the radical concentration is measured as set out in the specification.
  14. The method for producing a multilayered container according to claim 13, wherein, in the step 2, the multilayered container molded body is irradiated with an electron beam from the inside.

Description

Technical Field The present invention relates to a resin laminate, a multilayered film, and a multilayered container. Background Art Polyester resins, exemplified by polyethylene terephthalate (PET), excel in characteristics such as transparency, mechanical properties, melt stability, and recyclability, and therefore are currently widely used in various packaging materials such as films, sheets, and hollow containers. However, with films and hollow containers made from only a polyester resin, the gas barrier properties with respect to gases such as oxygen are not sufficient. Thus, multilayered bodies and multilayered containers having a polyamide resin layer are being examined. Furthermore, there are attempts to irradiate these multilayered bodies and multilayered containers with electron beams. For example, Patent Document 1 discloses, for the purpose of producing a laminate excelling in strength, gas permeation resistance, pin hole resistance, and flexibility, a method of producing a laminate by irradiating a polyamide resin film or a polyester resin film with electron beams, and then overlaying and adhering the film surface irradiated with electron beams. Furthermore, Patent Document 2 discloses a container made from a polyethylene terephthalate-based resin irradiated with radiation after being molded to improve oxygen scavenging and oxygen barrier properties. Patent Document 3 discloses a co-injection stretch blow moulding container for foodstuffs, consisting of a polyester layer and a preset gas-barrier resin layer, to be selected from PVOH, EVOH or MXD6, said container being irradiated with electron beam, infrared rays, ultraviolet-ray, X-ray, alpha ray and/or gamma ray. Citation List Patent Documents Patent Document 1: JP 2012-254594 APatent Document 2: JP 2003-285879 APatent Document 3: JP 2005-088901 A Summary of Invention Technical Problem As described in Patent Document 1, irradiating a laminate or container having a polyamide resin layer and a polyester resin layer with electron beams can improve interlayer adhesiveness to some extent, but irradiation with electron beams results in another problem of discoloration, where the resin turned to yellow. Therefore, a demand has existed for a colorless multilayered film and multilayered container that excel in gas barrier properties and adhesiveness between resin layers and exhibit no yellowing. Thus, an object of the present invention is to provide a resin laminate, a multilayered film, and a multilayered container having excellent gas barrier properties, excellent adhesiveness between layers, and excellent achromaticity. Solution to Problem As a result of diligent research in light of the problems described above, the present inventors discovered that the problems above can be solved by having a specific concentration of a radical in a resin laminate including a polyester layer and a mixed resin layer containing a specific polyamide resin and polyester resin, and with this discovery, the present inventors arrived at the present invention. The present invention is defined by appended claims 1-14, as follows: (1) A resin laminate including: a polyester layer containing a polyester resin (A); and a mixed resin layer containing a polyamide resin (B) and a polyester resin (C); wherein the polyamide resin (B) includes a constituent unit derived from a diamine and a constituent unit derived from a dicarboxylic acid, 70 mol% or greater of the constituent derived from a diamine being a constituent unit derived from xylylenediamine, and 70 mol% or greater of the constituent unit derived from a dicarboxylic acid being a constituent unit derived from an α,ω-linear aliphatic dicarboxylic acid having from 4 to 20 carbons; a content of the polyamide resin (B) in the mixed resin layer is not less than 70 mass% based on the mixed resin layer; the resin laminate is irradiated with an electron beam and a radical concentration in the mixed resin layer is 1 × 10-12 mol/g to 2 000 000 x 10-12 mol/g.(2) The resin laminate according to (1), wherein a mass ratio [(B)/(C)] of the polyamide resin (B) to the polyester resin (C) in the mixed resin layer is from 70/30 to 95/5.(3) The resin laminate according to (1) or (2), wherein the polyester resin (A) includes a constituent unit derived from a dicarboxylic acid and a constituent unit derived from a diol, 90 mol% or greater of the constituent unit derived from a dicarboxylic acid being a constituent unit derived from terephthalic acid, and 90 mol% or greater of the constituent unit derived from a diol being a constituent unit derived from ethylene glycol.(4) The resin laminate according to any one of (1) to (3), wherein the polyester resin (C) includes a constituent unit derived from a dicarboxylic acid and a constituent unit derived from a diol, 90 mol% or greater of the constituent unit derived from a dicarboxylic acid being a constituent unit derived from terephthalic acid, and 90 mol% or greater of the constituent unit deri