Claims
- 1. A fire retardant laminate comprising adjacent layers of a substrate coated on both sides with a mixture of epoxy resin and a 3-hydroxypropylphosphine oxide having the formula: ##STR2## wherein R.sub.1 may be the same or a different radical selected from the group consisting of hydrogen, phenyl, hydroxymethyl and alkyl radicals of 1-4 carbon atoms, R.sub.2 may be the same or a different radical selected from the group consisting of hydrogen, hydroxymethyl, and alkyl radicals of 1-4 carbon atoms, R.sub.3 may be the same or a different radical selected from the group consisting of hydrogen and methyl radicals, R.sub.4 is an alkyl radical of 2-8 carbon atoms and n is either 1 or 2; and a hardener, said adjacent layers being bound together into each other by said epoxy resin mixture to form a unitary structure.
- 2. A method of preparing a fire resistant laminate which comprises dissolving a 3-hydroxypropylphosphine oxide having the formula: ##STR3## wherein R.sub.1 may be the same or a different radical selected from the group consisting of hydrogen, phenyl, hydroxymethyl and alkyl radicals of 1-4 carbon atoms, R.sub.2 may be the same or a different radical selected from the group consisting of hydrogen, hydroxymethyl, and alkyl radicals of 1-4 carbon atoms, R.sub.3 may be the same or a different radical selected from the group consisting of hydrogen and methyl radicals, R.sub.4 is an alkyl radical of 2-8 carbon atoms and n is either 1 or 2 in an epoxy resin heated above its melting point; dissolving dicyandiamide in said resin mixture; coating a plurality of pieces of glass cloth with said epoxy resin containing the 3-hydroxypropylphosphine oxide and molding under heat and pressure the coated glass cloth pieces to form a unitary laminate consisting of adjacent pieces of glass cloth impregnated with epoxy resin.
Parent Case Info
This application is a division of application Ser. No. 264,256, filed May 18, 1981, now U.S. Pat. No. 4,345,059, issued Aug. 17, 1982.
US Referenced Citations (11)
Foreign Referenced Citations (3)
Number |
Date |
Country |
2538675 |
Mar 1977 |
DEX |
782445 |
|
ZAX |
1487609 |
Oct 1977 |
GBX |
Divisions (1)
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Number |
Date |
Country |
Parent |
264256 |
May 1981 |
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