Abstract: The present invention relates to a process for preparing phosphinic esters which comprisesa) reacting elemental yellow phosphorus with alkyl halides in the presence of alkali metal hydroxide or alkaline earth metal hydroxide to form a mixture which comprises as main constituents the alkali metal salts and/or alkaline earth metal salts of alkylphosphonous acid, phosphorous acid and hypophosphorous acidb) removing the alkylphosphonous acid from the mixture obtained as described in a),c) esterifying the alkylphosphonous acid,d) adding the resultant ester of the alkylphosphonous acid to a compound having at least one C.dbd.C double bond.The invention likewise relates to the use of the phosphinic esters prepared by this process inter alia as flame retardants and as precursor for further syntheses.

Abstract: The present invention relates to a process for preparing phosphonous esters which comprisesa) reacting elemental yellow phosphorus with alkyl halides in the presence of alkali metal hydroxides and/or alkaline earth metal hydroxides to form a mixture which comprises, as main components, the alkali metal salts and/or alkaline earth metal salts of the alkylphosphonous, phosphorous and hypophosphorous acids,b) removing the alkylphosphonous acid from the mixture obtained by a)c) esterifying the alkylphosphonous acid.The invention likewise relates to the use of the phosphonous esters prepared by this process.

Abstract: The invention relates to a flame-resistant epoxy resin mixture comprising epoxy resins, phosphorus-containing compounds and a hardener, which comprises a phosphorus-containing compound of the formula I or II ##STR1## in which R1 and R2 are identical or different and are a straight-chain or branched alkyl radical of 1 to 8 carbon atoms, a cyclohexyl, cyclopentyl or aryl radical or an alkyl- or alkoxy-substituted alkyl radical of 1 to 18 carbon atoms, it also being possible for R1 and R2, together with the P atom, to form a ring, and m and n are 0 or 1, to a process for their preparation and to their use.

Abstract: The present invention relates to a storage-stable, phosphorus-modified epoxy resin having an epoxide value of 0.05 to 0.6 mol/100 g and comprising 5 to 25% by weight of an ester-anhydride formed from a phosphonic acid diester, phosphinic acid ester or mixture of these esters and phosphorus pentoxide, and to a process for its preparation by reaction of 95 to 75 parts by weight of an epoxy resin (A) having an epoxide value of 0.1 to 0.8 mol/100 g and 5 to 25 parts by weight of the ester-anhydride in the presence or absence of a solvent at -20 to 150.degree. C.

Abstract: The invention relates to a phosphorus-modified epoxy resin having an epoxide value of from 0.05 to 0.6 mol/100 g comprising structural units derived from(A) polyepoxide compounds having at least two epoxide groups per molecule and(B) phosphorus-containing dicarboxylic acids or phosphorus-containing carboxylic anhydrides,to a process for their preparation and to their use.

Abstract: The invention relates to a process for preparing soluble and/or meltable phosphorus-modified epoxy resins, which comprises reacting a polyepoxide compound having at least 2 epoxide groups per molecule with carboxyl-containing phosphinic or phosphonic acids.

Abstract: The invention relates to a flame-resistant epoxy resin mixture comprising epoxy resins, phosphorus-containing compounds and a curing agent, wherein the epoxy resin mixture comprises phosphorus-containing structural units of the formula I ##STR1## in which R1 is an alkyl or aryl group having from 1 to 10 carbon atoms, R2 is hydrogen or an alkyl group having from 1 to 4 carbon atoms and R is an alkylene, cycloalkylene or arylene group having from 2 to 20 carbon atoms.

Abstract: The invention relates to a phosphorus-modified epoxy resin having an epoxide value of from 0 to 1.0 mol/100 g, comprising structural units derived from(A) polyepoxide compounds having at least two epoxide groups per molecule and(B) diphosphinic acids,to a process for their preparation and to their use.

Abstract: The invention relates to flame-resistant epoxy resin mixtures comprising epoxy resins, phosphorus-containing compounds and a hardener, which comprise a phosphorus-containing compound of the formula I or II ##STR1## in which R is a linear or branched alkyl, cycloalkyl, aryl or alkylaryl group having 1 to 18 carbon atoms or is hydrogen, and R' is a linear or branched alkylene, cycloalkylene, arylene or alkylarylene group having 1 to 18 carbon atoms, to a process for their preparation and to their use.

Abstract: The invention relates to an expandable, halogen-free, flame-retardant coating composition comprising epoxy resins, polyphosphoric/polyphosphonic esters and a curing agent, which composition comprises from 75 to 95 parts by weight of epoxy resin and from 5 to 25 parts by weight of polyphosphoric/polyphosphonic ester and wherein the overall weight ratio of epoxy resin and polyphosphoric/polyphosphonic ester to curing agent is (1.1 to 10) to 1. The invention likewise relates to a process for preparing such coating compositions and to their use.