Bisphenol-A based polymers having low organic emissions

A low organic emission composition comprising a di-alkoxylated bisphenol-A dimaleate urethane dimethacrylate hybrid resin, an alkoxylated bisphenol-A diacrylate or dimethacrylate, ethylene glycol dimethacrylate and other vinyl monomers. The composition is useful in such applications as a substitute for prior art resins, such as polyester/vinyl ester based resins, typically used in fiberglass reinforced plastic applications.

TECHNICAL FIELD 
This invention relates to low organic emission compositions comprising an 
alkoxylated bisphenol-A based dimethacrylate urethane hybrid polymer in 
combination with one or more alkoxylated bisphenol-A dimethacrylate 
monomers. These compositions find use in applications such as fiberglass 
reinforced plastic applications. The polymers made from the compositions 
of the present invention may substitute for polyester/vinyl ester based 
polymers used in the art. 
BACKGROUND OF THE INVENTION 
U.K. Patent Nos. 1,352,063; 1,465,359; and U.S. Pat. No. 4,457,818 disclose 
vinyl urethane resins. The resins are prepared from a diisocyanate, a 
hydroxyl-terminated ester of acrylic or methacrylic acid, and a 
bisphenol-A based ester of maleic or fumaric acid. The resins are 
polymerized with styrene to give a thermoset polymer. These polymers are 
said to have improved properties over prior art vinyl urethane resins. 
Smeal et al., in U.S. Pat. Nos. 5,292,841; 5,393,830; 5,492,668; 5,501,830; 
5,500,171; and 5,534,211 disclose formations of low organic emission 
polyester based polymers with alkoxylated bisphenol-A dimethacrylate 
esters, ethylene glycol dimethacrylate and other vinyl monomers. In these 
polymers, the use of styrene is either eliminated, or significantly 
minimized. The results are polymers with typical physical properties that 
give off lower levels of organic emissions during the polymerization 
process. 
SUMMARY OF THE INVENTION 
Alkoxylated bisphenol-A dicarboxylic acid based dimethacrylate urethane 
hybrid resins (referred to herein as "hybrid resins") are typically 
prepared, as is known in the art, by reacting a polyol, an unsaturated 
dicarboxylic acid (herein interchangeable with anhydride), a hydroxyl 
terminated methacrylate ester and a diisocyanate. One typical synthesis of 
a hybrid resin includes reacting two moles of alkoxylated Bisphenol-A with 
one mole of an unsaturated dicarboxylic acid. The resulting diester is 
reacted with two moles of diisocyanate, and two moles of the hydroxyl 
terminated methacrylate ester. The hybrid resin has vinyl terminated end 
groups and a diacid double bond that act as cross-linking sites with other 
methacrylates such as alkoxylated bisphenol-A diacrylates or 
dimethacrylates (ABAD), ethylene glycol dimethacrylates (EGDM), and vinyl 
monomers. The hybrid resin is then blended, as is known in the art, with 
the alkoxylated bisphenol-A dimethacrylate, styrene and or vinyl toluene 
monomers and the remaining constituents. The resulting mixture is then 
polymerized. 
As with the polymers disclosed in the Smeal et al references, the polymers 
of the present invention give off lower levels of volatile emissions 
during polymerization than similar polymers in the art. The polymers of 
the present invention will emit no more than about 20 g/m.sup.2 as 
measured by Rule 1162 Standard Method for Static Volatile Emissions of the 
South Coast Air Quality Management District (California), as set forth in 
the Smeal et al patents. The benefits associated with polymers, useful in 
laminating operations, emitting low levels of organic emissions is well 
known in the art. The present invention is the first known application to 
the art of these hybrid polymers in this type of application. 
Additionally, these polymers are useful in molding applications.