Heat-recoverable article, method for manufacturing heat-recoverable article, wire splice, and wire harness

Patent metadata

Field	Value
Publication number	US-10439384-B2
Application number	US-201615568804-A
Country	US
Kind code	B2
Filing date	Mar 22, 2016
Priority date	Apr 28, 2015
Publication date	Oct 8, 2019
Grant date	Oct 8, 2019

Abstract

The heat-recoverable article according to the present invention has a cylindrical shape and includes a base material layer. The base material layer contains a polyolefin-based resin. In the base material layer after being heated at 180° C. for 2 minutes, a melting-point peak temperature is 115° C. or higher and 128° C. or lower, a heat of fusion of a total resin component is 80 J/g or more and 150 J/g or less, a storage modulus at 120° C. is 4 MPa or more, a gel fraction is 40% by mass or more and 80% by mass or less, and a storage modulus at 180° C. is 0.5 MPa or more and less than 3.0 MPa. The polyolefin-based resin is preferably a mixture of a first polyolefin-based resin having a melting point of 125° C. or higher and 135° C. or lower and a second polyolefin-based resin having a melting point of lower than 125° C.

First claim

The invention claimed is:

1. A heat-recoverable article having a cylindrical shape, the heat-recoverable article comprising a base material layer,
wherein the base material layer contains a polyolefin-based resin, and
in the base material layer after being heated at 180° C. for 2 minutes, a melting-point peak temperature is 115° C. or higher and 128° C. or lower, a heat of fusion of a total resin component is 80 J/g or more and 150 J/g or less, a storage modulus at 120° C. is 4 MPa or more, a gel fraction is 40% by mass or more and 80% by mass or less, and a storage modulus at 180° C. is 0.5 MPa or more and less than 3.0 MPa,
wherein the polyolefin-based resin is a mixture of a first polyolefin-based resin having a melting point of 125° C. or higher and 135° C. or lower and a second polyolefin-based resin having a melting point of lower than 125° C., and a mass ratio of the first polyolefin-based resin to the second polyolefin-based resin is 60/40 or more, and
wherein the first polyolefin-based resin is a high-density polyethylene.

2. The heat-recoverable article according to claim 1 , wherein the high-density polyethylene has a melt flow rate (MFR) of 5 g/10 min or less.

3. The heat-recoverable article according to claim 1 , wherein the high-density polyethylene has a density of 0.930 g/cm 3 or more and 0.960 g/cm 3 or less.

4. The heat-recoverable article according to claim 1 , wherein the second polyolefin-based resin is a linear low-density polyethylene, a low-density polyethylene, a very low-density polyethylene, a polyolefin-based elastomer, or a combination thereof.

5. The heat-recoverable article according to claim 4 , wherein the polyolefin-based elastomer is a polyethylene-based elastomer obtained by copolymerizing ethylene with at least any of butene, hexene, and octene or an ethylene-propylene copolymer elastomer.

6. The heat-recoverable article according to claim 4 , wherein the polyolefin-based elastomer has a Mooney viscosity of 10 or more at 100° C.

7. The heat-recoverable article according to claim 1 , wherein a time until a heat shrinkage ratio of the base material layer reaches 80% after the heat-recoverable article is placed in an atmosphere at 200° C. is less than 50 seconds.

8. The heat-recoverable article according to claim 1 , comprising an adhesive layer formed on an inner circumferential surface of the base material layer.

9. The heat-recoverable article according to claim 8 , wherein the adhesive layer contains an ethylene-vinyl acetate copolymer or a polyamide.

10. A wire splice comprising:
a plurality of wires each of which includes a conductor and an insulating layer formed on the outside of the conductor; and
a tube adhering to a portion where the conductors of the plurality of wires are connected together, the tube being formed by thermally shrinking the heat-recoverable article according to claim 1 .

11. A wire harness comprising:
a plurality of wires each of which includes a conductor and an insulating layer formed on the outside of the conductor; and
a tube adhering to the plurality of wires, the tube being formed by thermally shrinking the heat-recoverable article according to claim 1 .

12. The heat-recoverable article according to claim 1 , wherein the mass ratio of the first polyolefin-based resin to the second polyolefin-based resin is 60/40 or more and 85/15 or less.

13. The heat-recoverable article according to claim 1 , wherein the mass ratio of the first polyolefin-based resin to the second polyolefin-based resin is 80/20 or more and 85/15 or less.

14. The heat-recoverable article according to claim 1 , wherein the second polyolefin-based resin is a linear low-density polyethylene, a low-density polyethylene, a very low-density polyethylene, or a combination thereof, and
wherein the polyethylene of the second polyolefin-based resin has a melting point of 55° C. or lower.

15. A method for manufacturing a heat-recoverable article, comprising:
a step of molding a resin composition containing a polyolefin-based resin so as to obtain a molded body having a cylindrical shape; and
a step of forming a base material layer by expanding a diameter of the molded body,
wherein in the base material layer after being heated at 180° C. for 2 minutes, a melting-point peak temperature is 115° C. or higher and 128° C. or lower, a heat of fusion of a total resin component is 80 J/g or more and 150 J/g or less, a storage modulus at 120° C. is 4 MPa or more, a gel fraction is 40% by mass or more and 80% by mass or less, and a storage modulus at 180° C. is 0.5 MPa or more and less than 3.0 MPa,
wherein the polyolefin-based resin is a mixture of a first polyolefin-based resin having a melting point of 125° C. or higher and 135° C. or lower and a second polyolefin-based resin having a melting point of lower than 125° C., and a mass ratio of the first polyolefin-based resin to the second polyolefin-based resin is 60/40 or more, and
wherein the first polyolefin-based resin is a high-density polyethylene.

Assignees

• Sumitomo Electric Industries
• Sumitomo Electric Fine Polymer Inc

Inventors

• Yamasaki Satoshi
• Nishikawa Shinya
• Emoto Yasutaka
• Sekiguchi Mamoru

Classifications

• H01B19/00

  Apparatus or processes specially adapted for manufacturing insulators or insulating bodies {(manufacture of porcelain for electric insulation C04B33/26)} · CPC title

• H01B7/28

  {Protection against damage caused} by moisture, corrosion, chemical attack or weather · CPC title

• H01B3/30

  plastics; resins; waxes · CPC title

• C08L23/00

  Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers · CPC title

• B29K2105/0097

  Glues or adhesives, e.g. hot melts or thermofusible adhesives · CPC title