Reconstituted mica materials, reconstituted mica prepreg materials, reconstituted mica products and insulated coils
AssigneeHitachi Chemical Company, Ltd.
InventorsHideji Kuwajima, Kazuyoshi Shike, Takeyoshi Watanabe
Life of this patent
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Abstract
A reconstituted mica material produced by sheet forming a slurry containing mica flakes prepared by disintegrating unfired mica and comprising (i) mica flakes having a particle size of 1.0 mm or more and an aspect ratio of 150 or more, (ii) mica flakes having a particle size of 0.25 mm or more and less than 1.0 mm and (iii) mica flakes having a particle size of less than 0.25 mm, in definite ranges, gives reconstituted mica prepreg materials, reconstituted mica products and insulated coils having excellent mechanical and electrical properties.
Claims16
A reconstituted mica material produced by sheet forming a slurry containing mica flakes prepared by disintegrating unfired mica and comprising:
- (i) 30 to 70 parts by weight of mica flakes having a particle size of 1.0 mm or more and an aspect ratio of 150 or more,
- (ii) 20 to 40 parts by weight of mica flakes having a particle size of 0.25 mm or more and less than 1.0 mm, and
- (iii) 10 to 30 parts by weight of mica flakes having a particle size of less than 0.25 mm.
A reconstituted mica prepreg material produced by sheet forming a slurry containing mica flakes prepared by disintegrating unfired mica and comprising:
- (i) 30 to 70 parts by weight of mica flakes having a particle size of 1.0 mm ormore and an aspect ratio of 150 or more,
- (ii) 20 to 40 parts by weight of mica flakes having a particle size of 0.25 mm or more and less than 1.0 mm, and
- (iii) 10 to 30 parts by weight of mica flakes having a particle size of less than 0.25 mm, to give a reconstituted mica material,
- impregnating or coating the reconstituted mica material with a thermosetting resin composition, and
- partially curing the impregnated or coated resin.
A reconstituted mica product produced by sheet forming a slurry containing mica flakes prepared by disintegrating unfired mica and comprising:
- (i) 30 to 70 parts by weight of mica flakes having a particle size of 1.0 mm or more and an aspect ratio of 150 or more,
- (ii) 20 to 40 parts by weight of mica flakes having a particle size of 0.25 mm or more and less than 1.0 mm, and
- (iii) 10 to 30 parts by weight of mica flakes having a particle size of less than 0.25 mm, to give a reconstituted mica material,
- impregnating or coating the reconstituted mica material with a thermosetting resin composition or an inorganic composition, and
- molding the resulting material with heating under pressure.
An insulated electrical coil comprising an electrical conductor and an insulating layer wrapped around said conductor, said insulating layer comprises:
- (a) 60 to 85 parts by weight of reconstituted mica material produced by sheet forming a slurry containing mica flakes prepared by disintegrating unfired mica and comprising:
- (i) 30 to 70 parts by weight of mica flakes having a particle size of 1.0 mm or more and an aspect ratio of 150 or more,
- (ii) 20 to 40 parts by weight of mica flakes having a particle size of 0.25 mm or more and less than 1.0 mm, and
- (iii) 10 to 30 parts by weight of mica flakes having a particle size of less than 0.25 mm,
- (b) 10 to 30 parts by weight of a thermosetting resin composition, and
- (c) 15 parts by weight or less of a backing material, the total weight of (a), (b) and (c) being 100 parts by weight.
Dependencies are inferred from the claim text.