Claims
- 1. A coextruded, biaxially stretched and laminated heat-shrinkable tubular film, comprising:
- (1) a gas-barrier layer of a copolymer of vinylidene chloride having a thickness of not less than 6 .mu.m, which is not more than 30% of the total thickness of the coextruded, biaxially stretched and laminated heat-shrinkable tubular film,
- (2) outer layers prepared from at least one polymer selected from the group consisting of:
- (i) a copolymer of ethylene and vinyl acetate having a crystal melting point ranging from 80.degree. to 103.degree. C.,
- (ii) a linear low-density polyethylene having a crystal melting point ranging from 110 to 130.degree. C.,
- (iii) a mixture of more than 0% and not more than 40% by weight of a linear-low density polyethylene having a crystal melting point ranging from 110.degree. to 130.degree. C., and not less than 60% and less than 100% by weight of a copolymer of ethylene and vinyl acetate having a crystal melting point ranging from 80.degree. to 103.degree. C., and
- (iv) a mixture of more than 40% by weight and less than 100% by weight of a linear low-density polyethylene of a density in the range of 0.915 to 0.930 and more than 0% by weight and less than 60% by weight of a copolymer of ethylene and vinyl acetate of a crystal melting point in the range of 80.degree. to 103.degree. C.,
- said outer layers having a thickness of 40 to 92% of the total thickness of the coextruded, biaxially stretched and laminated heat-shrinkable tubular film,
- (3) at least one intermediate layer of a polyamide or a thermoplastic polyester, both of which show a crystal melting point of not more than 240.degree. C., said intermediate layer having a thickness of 5 to 40% of the total thickness of the coextruded, biaxially stretched and laminated heat-shrinkable tubular film, and
- (4) adhesive layers disposed between all or certain polymer layers, each adhesive layer having a thickness of 0.5 to 5.0 .mu.m, and
- the total thickness of the coextruded, biaxially stretched and laminated heat-shrinkable tubular film being in the range of 25 to 110 .mu.m
- said coextruded, biaxially stretched and laminated heat-shrinkable tubular film being produced by laminating and co-extruding the copolymer of vinylidene chloride, the polyolefin, polyamide or the thermoplastic polyester and the adhesive material, cooling, heating and stretching the resultant laminated tubular film.
- 2. A coextruded, biaxially stretched and laminated heat-shrinkable tubular film according to claim 1, wherein one of the outer layers is a linear low-density polyethylene of a density in the range of 0.915 to 0.930, and the other outer layer of (i) a linear low-density polyethylene of a density in the range of 0.915 to 0.930, or (ii) a mixture of not less than 60% by weight and less than 100% by weight of a copolymer of ethylene and vinyl acetate of a crystal melting point in the range of 80.degree. to 103.degree. C., and more than 0% by weight and not more than 40% by weight of a linear low-density polyethylene of a density in the range of 0.915 to 0.930.
- 3. A coextruded, biaxially stretched and laminated heat-shrinkable tubular film according to claim 1, wherein one of the outer layers of a mixture is more than 40% by weight and less than 100% by weight of a linear low-density polyethylene of a density in the range of 0.915 to 0.930 and more than 0% by weight and less than 60% by weight of a copolymer of ethylene and vinyl acetate of a crystal melting point in the range of 80.degree. to 103.degree. C., and the other outer layer is (i) a linear low-density polyethylene of a density in the range of 0.915 to 0.930, (ii) a copolymer of ethylene and vinyl acetate of a crystal melting point in the range of 80.degree. to 103.degree. C., or (iii) a mixture of a copolymer of ethylene and vinyl acetate of a crystal melting point in the range of 80.degree. to 103.degree. C., and a linear low-density polyethylene of a density in the range of 0.915 to 0.930.
- 4. The coextruded, biaxially stretched and laminated heat-shrinkable tubular film according to claim 1, wherein the thickness of the gas-barrier layer is not less than 6 .mu.m and not more than 25% of the total thickness of the coextruded, biaxially stretched and laminated heat-shrinkable tubular film,
- the thickness of the outer layer is the range of 40 to 92% of the total thickness of the coextruded, biaxially stretched and laminated heat-shrinkable tubular film,
- the thickness of the intermediate layer(s) of a polyamide or a thermoplastic polyester is in the range of 5 to 20% of the total thickness of the coextruded, biaxially stretched and laminated heat-shrinkable tubular film, and
- the thickness of each adhesive layer is 0.5 to 3.0 .mu.m.
- 5. The coextruded biaxially stretched and laminated heat-shrinkable tubular film according to claim 1, wherein the comonomer copolymerizable with vinylidene chloride is vinyl chloride, acrylonitrile, or C.sub.1 -C.sub.18 -alkyl acrylate.
- 6. The coextruded, biaxially stretched and laminated heat-shrinkable tubular film according to claim 1, wherein said polyamide is Nylon 6-66 (a copolymer of .epsilon.-caprolactam and hexamethyleneadipamide), Nylon 6,10 (polyhexamethylene sebacamide), Nylon 6-12 (a copolymer of .epsilon.-caprolactam and ring-opened laurinlactam), Nylon 11 (polyundecaneamide), Nylon 12 (a polymer of ring opened laurinlactam), Nylon 6 (polycapramide), or a mixture of Nylon 6-66, Nylon 6,10, Nylon 6-12, Nylon 11, Nylon 12 or Nylon 6 and a Nylon comprising hexamethylenediamine and an aromatic dibasic acid.
- 7. The coextruded, biaxially stretched and laminated heat-shrinkable tubular film according to claim 1, wherein said polyester is a polymer prepared by condensing an aliphatic dibasic acid or an aromatic dibasic acid with an aliphatic glycol, a cycloaliphatic glycol or an aromatic glycol.
Priority Claims (1)
Number |
Date |
Country |
Kind |
58-228116 |
Dec 1983 |
JPX |
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CROSS-REFERENCE TO RELATED APPLICATION
The present invention is a continuation-in-part of application Ser. No. 675,307, filed on Nov. 27, 1984, now U.S. Pat. No. 4,732,795.
US Referenced Citations (4)
Foreign Referenced Citations (1)
Number |
Date |
Country |
2516067 |
May 1983 |
FRX |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
675307 |
Nov 1984 |
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