Flame retardant silicone rubber compositions containing carboxamides

Claim 1

A flame retardant silicone rubber composition comprising (A) 100 parts by weight of a polydiorganosiloxane of the average unit formula ##EQU3## in which each R is a monovalent radical selected from the group consisting of hydrocarbon radicals and halogenated hydrocarbon radicals and a has a value of from 1.95 to 2.05 inclusive, (B) 0 to 150 parts by weight of a fine particle silica filler, (C) 1 to 200 ppm by weight of platinum based on the weight of (A), in the form of platinum or a platinum-containing compound, (D) 0.01 to 5 parts by weight of carboxamide being formed from an acid selected from a monobasic acid, a multibasic acid, and a hydroxycarboxylic acid which acid is selected from carbonic acid, formic acid, aliphatic carboxylic acids, and aromatic carboxylic acids; which carboxamide is an amide which is a primary amide, a secondary amide, or a tertiary amide in which the amide contains alkyl, aryl, or hydrogen atoms bonded to nitrogen, and (E) 0.1 to 5 parts by weight of an organic peroxide.

Claim 18

A method for preparing a flame retardant silicone rubber composition comprising (I) mixing (A) 100 parts by weight of a polydiorganosiloxane gum of the average unit formula ##EQU4## in which each R is a monovalent radical selected from the group consisting of hydrocarbon radicals and halogenated hydrocarbon radicals and a has a value of from 1.95 to 2.05 inclusive, (B) 5 to 150 parts by weight of a fine particle silica filler, and optionally a processing aid, to obtain a mixture, (II) heating the mixture obtained in (I) to a temperature of 50° to 250° C. for at least 10 minutes, (III) cooling the mixture, and thereafter (IV) admixing with the mixture (C) 1 to 200 parts by weight platinum per 1,000,000 parts by weight of (A)) or an amount of a platinum compound sufficient to provide from 1 to 200 parts by weight of platinum per 1,000,000 parts by weight of (A), (D) 0.01 to 5 parts by weight of a carboxamide being formed from an acid selected from a monobasic acid, a multibasic acid, and a hydroxycarboxylic acid which acid is selected from carbonic acid, formic acid, aliphatic carboxylic acids, and aromatic carboxylic acids; which carboxamide is an amide which is a primary amide, a secondary amide, or a tertiary amide in which the amide contains alkyl, aryl, or hydrogen atoms bonded to nitrogen, and (E) 0.15 to 5 parts by weight of an organic peroxide.

Claim 19

A method for preparing a flame retardant silicone rubber composition comprising (I) mixing (A) 100 parts by weight of a polydiorganosiloxane gum of the average unit formula ##EQU4## in which each R is a monovalent radical selected from the group consisting of hydrocarbon radicals and halogenated hydrocarbon radicals and a has a value of from 1.95 to 2.05 inclusive, (B) 5 to 150 parts by weight of a fine particle silica filler, and optionally a processing aid, to obtain a mixture, (II) heating the mixture obtained in (I) to a temperature of 50° to 250° C. for at least 10 minutes, (III) cooling the mixture, and thereafter (IV) admixing with the mixture (C) 1 to 200 parts by weight platinum per 1,000,000 parts by weight of (A)) or an amount of a platinum compound sufficient to provide from 1 to 200 parts by weight of platinum per 1,000,000 parts by weight of (A), (D) 0.01 to 5 parts by weight of a carboxamide being formed from an acid selected from a monobasic acid, a multibasic acid, and a hydroxycarboxylic acid which acid is selected from carbonic acid, formic acid, aliphatic carboxylic acids, and aromatic carboxylic acids; which carboxamide is an amide which is a primary amide, a secondary amide, or a tertiary amide in which the amide contains alkyl, aryl, or hydrogen atoms bonded to nitrogen, and (E) 0.15 to 5 parts by weight of an organic peroxide.