Flame-retardant epoxy resin compositions
First Claim
1. A flame-retardant epoxy resin composition comprising 100 parts by weight of a polyepoxide containing more than one epoxy group in its molecule, 0.8 to 1.2 equivalents of an acid anhydride curing agent per equivalent of the polyepoxide, 0.5 to 5 parts by weight of an imidazole curing agent per 100 parts by weight of said polyepoxide, and amounts of aluminum trihydrate powder and at least one member selected from the group consisting of red phosphorus powder and red phosphorus powder coated by a thermo-setting resin within the range surrounded by connecting the points A, B, C, D, E, F, G, H and I as described below per 100 parts by weight of said polyepoxide, wherein the points A, B, C, D, E, F, G, H and I each represent the following compositions:
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space="preserve" listing-type="tabular">______________________________________ Red phosphorus Aluminum powder or red trihydrate phosphorus powder powder coated by a thermo- (parts by setting resin weight) (parts by weight) ______________________________________ A 72 50 B 83 20 C 103 10 D 160 5 E 220 4 F 198 20 G 178 31 H 154 40 I 112 46 ______________________________________
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Abstract
Flame-retardant epoxy resin compositions comprising a polyepoxide, an acid anhydride curing agent, an imidazole curing accelerator, aluminum trihydrate powder and red phosphorus powder or red phosphorus powder coated by a thermo-setting resin have a lower viscosity and therefore show a longer pot life and better workability on casting as compared with prior art resin compositions. Also, a fly-back transformer coil produced by casting of said flame-retardant epoxy resin compositions is flame-retardant. Even if it burns slightly, no toxic gas is produced. Therefore, the coil has advantages in that a magnet wire is not corroded and voids are difficult to be formed and thereby partial discharge is difficult to occur, resulting in a long life and a stable output voltage.
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Citations
22 Claims
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1. A flame-retardant epoxy resin composition comprising 100 parts by weight of a polyepoxide containing more than one epoxy group in its molecule, 0.8 to 1.2 equivalents of an acid anhydride curing agent per equivalent of the polyepoxide, 0.5 to 5 parts by weight of an imidazole curing agent per 100 parts by weight of said polyepoxide, and amounts of aluminum trihydrate powder and at least one member selected from the group consisting of red phosphorus powder and red phosphorus powder coated by a thermo-setting resin within the range surrounded by connecting the points A, B, C, D, E, F, G, H and I as described below per 100 parts by weight of said polyepoxide, wherein the points A, B, C, D, E, F, G, H and I each represent the following compositions:
space="preserve" listing-type="tabular">______________________________________ Red phosphorus Aluminum powder or red trihydrate phosphorus powder powder coated by a thermo- (parts by setting resin weight) (parts by weight) ______________________________________ A 72 50 B 83 20 C 103 10 D 160 5 E 220 4 F 198 20 G 178 31 H 154 40 I 112 46 ______________________________________- View Dependent Claims (2, 3, 4, 5, 6, 7, 15, 16, 17, 18, 19, 20, 21)
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8. A flame-retardant epoxy resin composition comprising 100 parts by weight of a polyepoxide containing more than one epoxy group in its molecule, 0.8 to 1.2 equivalents of an acid anhydride curing agent per equivalent of the polyepoxide, 0.5 to 5 parts by weight of an imidazole curing agent per 100 parts by weight of said polyepoxide, and amounts of aluminum trihydrate powder and red phosphorus powder coated by a thermo-setting resin within the range surrounded by connecting the points A, B, C, D, E, F, G, H and I as described blow per 100 parts by weight of said polyepoxide, wherein the points A, B, C, D, E, F, G, H and I each represent the following compositions:
space="preserve" listing-type="tabular">______________________________________ Aluminum Red phosphorus trihydrate powder coated powder by a thermo- (parts by setting resin weight) (parts by weight) ______________________________________ A 72 50 B 83 20 C 103 10 D 160 5 E 220 4 F 198 20 G 178 31 H 154 40 I 112 46 ______________________________________- View Dependent Claims (9, 10, 11, 12, 13, 14, 22)
Specification