Vinyl acetate based alkaline resistant scrim binder

Abstract

Disclosed is an aqueous formulation comprising a polymer which is based on a vinyl acetate copolymer, a binder system comprising said aqueous formulation and additionally an aqueous formulation comprising polymer (B). The invention further relates to a fibrous product comprising a fibrous substrate as well as the aqueous formulation or the binder system and use of the aqueous formulation or the binder system for coating synthetic or mineral fibres, for the manufacturing of Eternal Insulation Finishing Systems (EIFS), for increasing the alkali resistance of synthetic or mineral fibres and use in a process for the manufacturing of an alkali resistant glass fibre scrim. Further, the invention relates to a method for the manufacturing of the aqueous formulation.

1 . A fibrous product comprising a glass fibre scrim and an aqueous formulation comprising polymer (A) which is obtainable by polymerizing a monomer mixture comprising
 a) 55 to 90 wt.-% vinyl acetate,   b) 5 to 40 wt.-% ethylene,   c) 0.5 to 10 wt.-% of an ethylenically unsaturated self crosslinking agent and   d) up to 10 wt.-% of ethylenically unsaturated monomers which are different from monomers a) to c),   via free radical emulsion polymerization and   wherein the weight is based on the total weight of monomers in the monomer mixture.   
     
     
         2 . A fibrous product according to  claim 1  wherein said monomer mixture comprises
 a) 60 to 85 wt.-% vinyl acetate, 
 b) 10 to 35 wt.-% ethylene, 
 c) 1 to 8 wt.-% of an ethylenically unsaturated self crosslinking agent and 
 d) up to 5 wt.-%, preferably up to 2.5 wt.-% of ethylenically unsaturated monomers which are different from monomers a) to c), 
 wherein the weight is based on the total weight of monomers in the monomer mixture. 
 
     
     
         3 . A fibrous product according to  claim 1  wherein said monomer mixture comprises
 a) 65 to 80 wt.-% vinyl acetate, 
 b) 15 to 30 wt.-% ethylene, 
 c) 2 to 6 wt.-% of an ethylenically unsaturated self crosslinking agent and 
 d) up to 0.5 wt.-% of ethylenically unsaturated monomers which are different from monomers a) to c), 
 wherein the weight is based on the total weight of the monomers in the monomer mixture. 
 
     
     
         4 . A fibrous product according to  claim 1  wherein said monomer mixture comprises
 a) 70 to 75 wt.-% vinyl acetate, 
 b) 20 to 25 wt.-% ethylene, 
 c) 3 to 6 wt.-% of an ethylenically unsaturated self crosslinking agent and 
 d) up to 0.5 wt.-% of ethylenically unsaturated monomers which are different from monomers a) to c) 
 wherein the weight is based on the total weight of monomers in the monomer mixture. 
 
     
     
         5 . A fibrous product according to  claim 1  wherein polymer (A) has a glass transition temperatures (Tg) of less than 25° C., determined according to ASTME 1356. 
     
     
         6 . A fibrous product according to  claim 1 , wherein the ethylenically unsaturated self crosslinking agent (monomer c)) is at least one selected from the group consisting of acrylamidoglycolic acid (AGA), methyl acrylamidoglycolate methyl ether, N-methylolacrylamide (NMA), N-methylolmethacrylamide (NMMA), allyl-N-methylolcarbamate, alkyl ether of N-methylolacrylamide, of N-methylolmethacrylamide and of allyl-N-methylolcarbamate, ester of N-methylolacrylamide, of N-methylolmethacrylamide and of allyl-N-methylolcarbamate. 
     
     
         7 . A fibrous product according to  claim 1 , wherein the ethylenically unsaturated self crosslinking agent (monomer c)) is N-methylolacrylamide (NMA) and/or N-methylolmethacrylamide (NMMA). 
     
     
         8 . A fibrous product according to  claim 1 , wherein monomer d) is an ethylenically unsaturated monomer which bears at least one acid and/or acid salt group, preferably selected from the group consisting of carboxylic acid, sulfonic acid, phosphoric acid, phosphonic acid and the alkali metal salts or ammonium salts thereof. 
     
     
         9 . A fibrous product according to  claim 1  wherein said aqueous formulation further comprises polymer (B) which is a polymer with a glass transition temperature (Tg) ranging from 10 to 50° C., determined according to ASTME 1356. 
     
     
         10 . A fibrous product according to  claim 9  wherein the weight ratio of polymer (A) to polymer (B) ranges from 1:99 to 99:1. 
     
     
         11 . A fibrous product according to  claim 9  wherein polymer (B) is a copolymer comprising monomer units selected from the group consisting of styrene, butadiene, (meth)acrylic derivatives, vinyl acetate and mixtures thereof. 
     
     
         12 . A fibrous product according to  claim 1  wherein the aqueous formulation is applied to the glass fibre scrim and subsequently cured. 
     
     
         13 . A fibrous product according to  claim 1  wherein the glass fibre scrim comprises transverse yarns and longitudinal yarns which are bonded at their crossover points. 
     
     
         14 . A fibrous product  claim 1 , wherein the glass fibre scrim has less than 155000 mesh openings per square meter and the individual yarns used to form the scrim have a size ranging from 1800 m/kg to 18000 m/kg. 
     
     
         15 . An external insulation finishing system comprising a fibrous product according to  claim 1 . 
     
     
         16 . An external insulation finishing system comprising a fibrous product according to  claim 9 . 
     
     
         17 . A method of producing a fibrous product, the method comprising:
 (i) polymerizing an aqueous monomer mixture comprising   a) 55 to 90 wt.-% vinyl acetate,   b) 5 to 40 wt.-% ethylene,   c) 0.5 to 10 wt.-% of an ethylenically unsaturated self crosslinking agent and   d) up to 10 wt.-% of ethylenically unsaturated monomers which are different from monomers a) to c), wherein the weight is based on the total weight of monomers in the monomer mixture   
       via free radical emulsion polymerization to produce an aqueous formulation comprising polymer (A) and
 (ii) applying said aqueous formulation to a glass fibre scrim. 
 
     
     
         18 . The method of  claim 17  and further comprising combining said aqueous emulsion with polymer B, which is a polymer with a glass transition temperature (Tg) ranging from 10 to 50° C., determined according to ASTME 1356, before applying said aqueous formulation to said glass fibre scrim. 
     
     
         19 . The method of  claim 18 , wherein polymer (B) is a copolymer comprising monomer units selected from the group consisting of styrene, butadiene, (meth)acrylic derivatives, vinyl acetate and mixtures thereof.