Fire retardant epoxy resins containing 3-hydroxyalkylphosphine oxides
AssigneeFMC Corporation
InventorsEdward R. Fretz, Jr., Joseph Green
Life of this patent
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Abstract
Epoxy resins are rendered fire retardant by the addition thereto of a 3-hydroxyalkylphosphine oxide. Other halogen containing flame retardants may or may not be present in the composition. Mixtures containing a brominated epoxide and/or a halogenated phosphine oxide provide a high level of flame retardance at low levels of the additive. The epoxy resins may be heat cured in the presence of an acid anhydride or amine to form a polymer having the phosphine oxide incorporated in the polymer molecule.
Claims2
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.
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.
Dependencies are inferred from the claim text.