Non-halogen flame retardant as coatings for fibrous filter media

Abstract

Non-halogenated monomers that can be polymerized into flame retardant polymers, and processes to produce the monomers and polymers is provided. In a simplest aspect, there is provided a monomer composition that can comprise a) a group derived from one of a (meth)acrylic acid, (meth)acrylamide, or vinylbenzene, b) a polyphosphate moiety, and c) an amine species. In the monomer composition, the ethylenically unsaturated monomer of (a) is covalently bonded directly or through a linking group to the moiety of b), forming a precursor monomer unit. The amine species of c) is in complex with the precursor monomer unit. The polymer can be a homopolymer of the monomer composition, or a copolymer of the monomer composition having varying a), b) and c). In one embodiment, the polymer can additionally comprise ethylenically unsaturated monomers not covalently bonded to a polyphosphate moiety.

What is claimed is: 
     
         1 . A coating composition for filter media comprising: an aqueous dispersion of a flame retardant polymer comprised of monomeric units derived from a flame retardant monomer composition comprised of:
 a) a group derived from one of a (meth)acrylic acid, (meth)acrylamide, or vinylbenzene,   b) a polyphosphate moiety, and   c) an amine species;   wherein a) is covalently bonded directly or through a linking group to b) forming a precursor monomer unit, and   wherein c) is in complex with the covalently bonded polyphosphate moiety of b) in the precursor monomer unit.   
     
     
         2 . The coating composition for filter media of  claim 1  wherein the polyphosphate moiety is derived from a polyphosphate or monophosphonate compound of formula —R 3 X—[P(═O)(OR 5 )O − ] n R 4 , or —R 3 —P(═O)(OR 4 )(OR 5 ), where:
 n is about 1 to about 10, 
 X is O or NH, 
 R 3  is a C 0 -C 50  hydrocarbyl linking group having oxygen and/or nitrogen atoms substitute for up to 20 of the carbon atoms, 
 R 4  is H, or M + , 
 R 5  is H, or M + , and 
 M +  is a counterion selected from elements in Groups I and II of the periodic table or ammonium. 
 
     
     
         3 . The coating composition for filter media according to  claim 1  wherein the polyphosphate moiety is carboxyethyl polyphosphate, carboxyethyl monophosphonate, carboamidoethyl polyphosphate, carboamidoethyl polyphosphonate, phenethyl polyphosphate, or phenethyl monophosphonate, or mixtures thereof. 
     
     
         4 . The coating composition for filter media according to  claim 1 , wherein the precursor monomer unit is selected from 2-hydroxyethyl (meth)acrylate polyphosphate ester, bis(2-hydroxyethyl (meth)acrylate polyphosphate ester, polyethylene glycol (meth)acrylate polyphosphate ester, polypropylene glycol (meth)acrylate polyphosphate ester, methacrylamidoethyl phosphonic acid, vinylbenzene phosphonic acid, vinyl phosphonic acid, and isopropenyl phosphonic acid. 
     
     
         5 . The coating composition for filter media according to  claim 1  wherein the amine species has a molecular weight of from about 16 to 3000 g/mole. 
     
     
         6 . The coating composition for filter media according to  claim 1  wherein the amine species is derived from dicyandiamide, an alkylamine, or guanidine. 
     
     
         7 . The coating composition for filter media according to  claim 1  wherein the flame retardant monomer composition is 2-(phosphonooxy)ethyl methacrylate complexed with guanyl urea or (2-(methacryloyloxy)ethyl)phosphonic acid complexed with guanyl urea. 
     
     
         8 . The coating composition for filter media according to  claim 1  wherein the polymer is a homopolymer. 
     
     
         9 . The coating composition for filter media according to  claim 1  wherein the polymer is a copolymer of the flame retardant monomer compositions having varying a), b) and c). 
     
     
         10 . The coating composition for filter media according to  claim 1 , additionally comprising ethylenically unsaturated monomers that are not covalently bonded to a polyphosphate moiety. 
     
     
         11 . The coating composition for filter media according to  claim 1 , wherein at least 20% of the monomers in the polymer are the flame retardant monomer compositions and from 0.1% to about 80% of the monomers in the polymer are the ethylenically unsaturated monomers that are not covalently bonded to a polyphosphate moiety, and wherein the polymer is comprised of at least 1 wt. % P and has a Mn of at least about 1000 g/mole; and wherein at least 90% of the monomers in the polymer comprise a combination of the ethylenically unsaturated monomers that are not covalently bonded to a polyphosphate moiety and the flame retardant monomer compositions, wherein said ethylenically unsaturated monomers that are not covalently bonded to a polyphosphate moiety are one or more of vinyl chloride, styrene, C 1 -C 40  alkyl (meth)acrylates, C 1 -C 40  (meth)acrylamides, acrylamide, N-methylolacrylamide, acrylonitrile, acrylic acid, methacrylic acid, itaconic acid, maleic acid, 2-acrylamido-2-methylpropane sulfonic acid, C 1 -C 40  hydroxyalkyl (meth)acrylates, C 1 -C 40  hydroxyalkyl (meth)acrylamide, vinyl esters, butadiene, isoprene and dimeric or multi-derivative compounds thereof. 
     
     
         12 . The coating composition for filter media according to  claim 1  wherein the phosphorus content is from about 1.0 to about 15.0 wt. % of the polymer. 
     
     
         13 . The coating composition for filter media according to  claim 1  wherein at least 50% of the monomers in the composition are selected from the flame retardant monomer compositions. 
     
     
         14 . The coating composition for filter media according to  claim 1 , and further comprising from about 1 to about 50 parts by weight of a flame retardant additive per 100 parts by weight of said flame retardant polymer. 
     
     
         15 . The coating composition for filter media of  claim 14 , wherein the flame retardant additive is one or more of a melamine derivative flame retardant, an organic flame retardant, an inorganic flame retardant, an organic phosphate, phosphonate or phosphinate flame retardant, a halogenated compound flame retardant, and mixtures thereof. 
     
     
         16 . The coating composition for filter media of  claim 15 , wherein the flame retardant additive is melamine cyanurate. 
     
     
         17 . The coating composition for filter media according to  claim 14  additionally blended with one or more polyurethane polymers, polyamide polymers, polyurea polymers, polyacrylate polymers or mixtures thereof. 
     
     
         18 . A filter comprised of a fibrous filter media and a flame retardant coating composition for filter media according to  claim 1 . 
     
     
         19 . A method of imparting flame retardancy to a fibrous filter media comprising applying to the fibrous filter media a coating composition for filter media according to  claim 1 .