Laminated insulating paper and oil-filled cable insulated thereby
AssigneeShowa Electric Wire & Cable Co., Ltd.
InventorsTakeshi Kojima, Sakae Kinoshita, Kenzo Takeuchi
Life of this patent
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Abstract
The present invention relates to a laminated insulating paper formed of cellulose paper or papers which is adhered to at least one side of cross-linked silicone grafted polyolefine film and to an oil-filled (OF) cable which insulated by the laminated insulating paper. The laminated insulating paper has outstanding peel strength as well as excellent non-solubility and anti-swelling properties in insulating oils.
Claims12
A laminated electrical insulating wrapping material comprising a plastic film of a cross-linked silicone grafted polyolefin and a cellulose paper or papers laminated to at least one side of said film, said laminated insulating material produced by the process comprising:
- (a) melt-extruding an un-cross-linked silicone grafted polyolefin to form a softened film;
- (b) superimposing said paper or papers onto one side of said softened film;
- (c) applying pressure to said superimposed paper and softened film to form a laminate;
- and
- (d) cross-linking said laminated silicone grafted polyolefin film by reaction with water in the presence of a silanol condensation catalyst and forming a chemical bond between the silyl groups of said silicone grafted polyolefin film and the hydroxyl groups of said cellulose paper.
A process for producing a laminated electrical insulating material comprising:
- (a) melt-extruding an un-cross-linked silicone grafted polyolefin to form a softened film;
- (b) superimposing a cellulose paper or papers onto one side of said softened film;
- (c) applying pressure to said superimposed paper and softened film to form a laminate;
- and
- (d) cross-linking said laminated silicone grafted polyolefin film by reaction with water in the presence of a silanol condensation catalyst and forming a chemical bond between the silyl groups of said silicone grafted polyolefin film and the hydroxyl groups of said cellulose paper.
A process for producing a laminated insulating paper which includes cellulose paper or papers laminated to at least one side of a plastic film, the process comprising the steps of:
- (a) extruding a mixture of un-cross-linked silicone grafted polyolefin pellets with master batch pellets of a silanol condensation catalyst to form a silicone grafted polyolefin film;
- (b) superimposing cellulose paper or papers on at least one side of said film;
- (c) applying pressure to laminate cellulose paper or papers and said superimposed extruded film while said film is still in a softened state;
- and
- (d) cross-linking said laminated silicone grafted polyolefin film by reaction with water in the presence of said silanol condensation catalyst and forming a chemical bond between the silyl groups of said silicone grafted polyolefin film and the hydroxyl groups of said cellulose paper.
A process for producing a laminated insulating paper which includes cellulose paper or papers laminated to at least one side of a plastic film, the process comprising the steps of:
- (a) extruding un-cross-linked silicone grafted polyolefin from an extruder to form a silicone grafted polyolefin film;
- (b) superimposing cellulose paper or papers on at least one side of said film;
- (c) applying pressure to laminate said superimposed cellulose paper or papers and extruded film while said film is still in a softened state;
- (d) cross-linking said silicone grafted polyolefin film of the laminate by reaction with water in the presence of a silanol condenation catalyst and forming a chemical bond between the silyl groups of said silicone grafted polyolefin film and the hydroxyl group of said cellulose paper;
- and
- (e) heat-treating the laminated film at a temperature of 40.degree.-150.degree. C. for a period of 30 minutes to 50 hours.
In an oil-filled electrical cable comprising an electric conductor, an insulating layer of wound laminated insulating paper applied over the electric conductor, an insulating oil impregnated in the insulating layer, and a metal sheath applied over the insulating layer, the improvement wherein:
- the laminated insulating paper comprises a plastic film formed of a cross-linked silicone grafted polyolefin film and cellulosic paper or papers laminated to at least one side thereof and produced by the process comprising,
- (a) melt-extruding an un-cross-linked silicone grafted polyolefin to form a softened film;
- (b) superimposing said paper or papers onto one side of said softened film;
- (c) applying pressure to said superimposed paper and softened film to form a laminate;
- and
- (d) cross-linking said laminated silicone grafted polyolefin film by reaction with water in the presence of a silanol condensation catalyst and forming a chemical bond between the silyl groups of said silicone grafted polyolefin film and the hydroxyl groups of said cellulose paper.
A laminated electrical insulating wrapping material comprising a plastic film of a cross-linked silicone grafted polyolefin and a cellulose paper or papers laminated to at least one side of said film, said laminated insulating material produced by the process comprising:
- (a) melt-extruding an un-cross-linked silicone grafted polyolefin to form a softened film;
- (b) superimposing said paper or papers onto one side of said softened film;
- (c) applying pressure to said superimposed paper and softened film to form a laminate;
- (d) cross-linking said laminated silicone grafted polyolefin film by reaction with water in the presence of a silanol condensation catalyst and forming a chemical bond between the silyl groups of said silicone grafted polyolefin film and the hydroxyl group of said cellulose paper;
- and
- (e) heat-treating the laminated film at a temperature of 40.degree.-150.degree. C. for a period of 30 minutes to 50 hours.
Dependencies are inferred from the claim text.