Heat-shrinkable laminate tubular film

• US 4,732,795 A
• Filed: 11/27/1984
• Issued: 03/22/1988
• Est. Priority Date: 12/02/1983
• Status: Expired due to Term

• Current Assignee: Kureha Kagaku Kogyo Kabushiki Kaisha
• Original Assignee: Kureha Kagaku Kogyo Kabushiki Kaisha
• Inventors: Ohya, Masaki, Nishimoto, Yoshiharu
• Primary Examiner(s): Kitle, John E.
• Assistant Examiner(s): Seidleck, James J.
• Application Number:
  US06/675,307
• Time in Patent Office: 1,211 Days
• Field of Search: 428/518, 428/56, 428/483, 428/475.8, 428/476.1, 428/926, 428/476.3, 428/476.9, 428/213, 428/214
• US Class Current: 428/34.9
• CPC Class Codes: B29C 2791/007 Using fluid under pressure
• CPC Class Codes: B29C 48/09 Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• CPC Class Codes: B29C 48/10 flexible, e.g. blown foils
• CPC Class Codes: B29C 48/1472 at the die nozzle exit zone
• CPC Class Codes: B29C 48/21 the layers being joined at their surfaces
• CPC Class Codes: B29C 48/336 the components merging one by one down streams in the die
• CPC Class Codes: B29C 61/0616 layered or partially layered preforms, e.g. preforms with layers of adhesive or sealing compositions B29C61/0625 and B29C61/065 take precedence
• CPC Class Codes: B29C 61/08 by stretching tubes in general B29C55/22, B29C55/28
• CPC Class Codes: B29K 2023/00 Use of polyalkenes or derivatives thereof as moulding material
• CPC Class Codes: B29K 2023/083 EVA, i.e. ethylene vinyl acetate copolymer
• CPC Class Codes: B29K 2027/00 Use of polyvinylhalogenides or derivatives thereof as moulding material
• CPC Class Codes: B29K 2067/00 Use of polyesters or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2077/00 Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as moulding material
• CPC Class Codes: B32B 2038/0028 Stretching, elongating
• CPC Class Codes: B32B 2307/736 Shrinkable
• CPC Class Codes: B32B 2323/046 LDPE, i.e. low density polyethylene
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/304 comprising vinyl halide (co)polymers, e.g. PVC, PVDC, PVF, PVDF
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 27/34 comprising polyamides
• CPC Class Codes: B32B 27/36 : comprising polyesters
• CPC Class Codes: B32B 7/12 : using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: Y10T 428/1328 : Shrinkable or shrunk [e.g., due to heat, solvent, volatile agent, restraint removal, etc.]
• CPC Class Codes: Y10T 428/1341 : Contains vapor or gas barrier, polymer derived from vinyl chloride or vinylidene chloride, or polymer containing a vinyl alcohol unit
• CPC Class Codes: Y10T 428/2495 : Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/24959 : of adhesive layers
• CPC Class Codes: Y10T 428/31743 : Next to addition polymer from unsaturated monomer[s]
• CPC Class Codes: Y10T 428/31746 : Polymer of monoethylenically unsaturated hydrocarbon
• CPC Class Codes: Y10T 428/3175 : Next to addition polymer from unsaturated monomer[s]
• CPC Class Codes: Y10T 428/31757 : Polymer of monoethylenically unsaturated hydrocarbon
• CPC Class Codes: Y10T 428/31797 : Next to addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/3192 : Next to vinyl or vinylidene chloride polymer

Abstract

Disclosed herein is a heat-shrinkable laminate tubular film comprising a gas-barrier layer of a copolymer of vinylidene chloride, outer layers of a polyolefin, 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° C. and have a specified thickness, and adhesive layers disposed between any of the above layers.

Claims

1. A coextruded, biaxially stretched and laminated heat-shrinkable tubular film, comprising:

a gas-barrier layer of a copolymer of vinylidene chloride having a thickness, which is not more than 30% of the total thickness of the coextruded, biaxially stretched and laminated heat-shrinkable tubular film, of not less than 6 μ

m, outer layers of a polyolefin, 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°

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 adhesive layers disposed between all or certain polymer layers, and

the total thickness of the coextruded, biaxially stretched and laminated heat-shrinkable tubular film being in the range of 20 to 120 micrometers,

the 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.

10. The coextruded, biaxially stretched and laminated heat-shrinkable tubular film according to claim 1, wherein said outer polyolefin layers are prepared from at least one polymer selected from the group consisting of:

(1) a copolymer of ethylene and vinyl acetate having a crystal melting point ranging from 80°

to 103°

C.,

(2) a linear low-density polyethylene having a crystal melting point ranging from 110°

to 130°

C., and

(3) 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°

to 130°

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°

to 103°

C.

2. A coextruded, biaxially stretched and laminated heat-shrinkable tubular film, comprising:

(A) a gas-barrier layer of a copolymer of vinylidene chloride having a thickness which is not more than 30% of the total thickness of the coextruded, biaxially stretched and laminated heat-shrinkable tubular film, of not less than 6 μ

m;

(B) outer layers which are of one of the following two combinations;

(1) one outer layer consisting essentially of a copolymer of ethylene and vinyl acetate of a crystal melting point ranging from 80°

to 103°

C. and the other outer layer consisting essentially of a linear low-density polyethylene of a crystal melting point ranging from 110°

to 130°

C.,

(2) both outer layers consisting essentially of a mixture of not more than 40% by weight of a linear low-density polyethylene of a crystal melting point ranging from 110°

to 130°

C. and not less than 60% by weight of a copolymer of ethylene and vinyl acetate of a crystal melting point ranging from 80°

to 103°

C., and

(C) 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°

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

(D) adhesive layers which are disposed between all or certain polymer layers.

the total thickness of the coextruded, biaxially stretched and laminated heat-shrinkable tubular film being in the range of 20 to 120 micrometers.

3. The coextruded, biaxially stretched and laminated heat-shrinkable tubular film according to claim 2, wherein both outer layers consist essentially of a copolymer of ethylene and vinyl acetate of a crystal melting point ranging from 80°

0 to 103°

C.

4. The coextruded, biaxially stretched and laminated heat-shrinkable tubular film according to claim 2, wherein both outer layers consist essentially of a mixture of more than 0% by weight and not more than 40% by weight of a linear low-density polyethylene of a crystal melting point ranging from 110°

to 130°

C., and 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 ranging from 80°

to 103°

C.

5. The coextruded, biaxially stretched and laminated heat-shrinkable tubular film according to claim 2, wherein one outer layer consists essentially of a mixture of more than 0% by weight and not more than 40% by weight of a linear low-density polyethylene of a crystal melting point ranging from 110°

to 130°

C., and 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 ranging from 80°

to 103°

C. and the other outer layer consists essentially of a copolymer of ethylene and vinyl acetate of a crystal melting point ranging from 80°

to 103°

C.

6. The coextruded, biaxially stretched and laminated heat-shrinkable tubular film according to claim 2, wherein the thickness of the gas-barrier layer is more than 6 μ

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 in 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 μ

m.

7. The coextruded, biaxially stretched and laminated heat-shrinkable tubular film according to claim 2, wherein the comonomer copolymerizable with vinylidene chloride is vinyl chloride, acrylonitrile, or C₁ -C₁₈ -alkyl acrylate.

8. The coextruded, biaxially stretched and laminated heat-shrinkable tubular film according to claim 2, wherein said polyamide is Nylon 6-66 (a copolymer of ε

-caprolactam and hexamethyleneadipamide), Nylon 6-10 (polyhexamethylene sebacamide), Nylon 6-12 (a condensate of hexamethylenediamine and 1,10-decanedicarboxylic acid), Nylon 11 (polyundecaneamide), Nylon 12 (a polymer of ring opened laurolactam), or Nylon 6 (polycapramide).

9. The coextruded, biaxially stretched and laminated heat-shrinkable tubular film according to claim 2, 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.