Flame and smoke spread retardant molding compounds and components molded from these compounds
View Patent ↗HVAC and building and construction components are molded from novel compositions that meet the flame spread and smoke index, and the molding, safety, strength, and aesthetic requirements for this use. In a further embodiment, these compounds also promote better indoor air quality by inhibiting the growth of microbial contaminants within and on the surface of products molded therefrom. These compounds are based on thermoset resin, e.g. a polyester resin which preferably can comprise a polypropylene glycol dicyclopentadiene copolymerized with maleic anhydride, a low profile additive and hydroxy ethyl methacrylate monomer with additional additives including an appropriate catalyst package, a mold release agent, a thickening agent, a loading of aluminum hydroxide which is from about 40 to 65% by weight, having a loading of glass fibers of from about 10 to about 25% and preferably containing a silver ion containing antimicrobial agent, such as soluble glass containing silver ions.
1. A component for an air handler or hot air furnace which is a molded product of a molding composition comprising:
a) a thermoset resin system comprising an unsaturated polyester prepolymer and a reactive monomer;
wherein the unsaturated polyester has a weight average molecular weight from 200 to 5,000 and a glass transition temperature of 150° C. to 175° C.; wherein the unsaturated polyester prepolymer is dissolved in the reactive monomer; wherein the unsaturated polyester prepolymer is a product of a condensation polymerization reaction between a polyol and an acid, anhydride, acid dimer, or anhydride dimer;
wherein the polyol is selected from the group consisting of ethylene glycol, propylene glycol, neopentyl glycol, diethylene glycol, dipropyleneglycol, trimethylpentanediol, cyclohexane diol, propoxylated bisphenol A, hydrogenated bisphenol A, and combinations thereof; wherein the acid, anhydride, acid dimer, or anhydride dimer is selected from the group consisting of phthalic anhydride, maleic anhydride, adipic acid, isophthalic acid, orthophthalic acid, terephthalic acid, fumaric acid, glutaric acid, azelaic acid, endomethylenetetrahydrophthalic anhydride, and combinations thereof;
wherein the reactive monomer comprises hydroxyethyl methacrylate, and optionally a monomer selected from the group consisting of styrene, α-methyl styrene, vinyl toluene, divinyl benzene, diallylphthalate, methyl methacrylate, and combinations thereof;
wherein the unsaturated polyester prepolymer is cross-linked during molding with a low profile additive selected from the group consisting of polymethylmethacrylate, polyethylmethacrylate, polystyrene, polystyrene copolymer, polyvinyl acetate, polyethylene, saturated polyester, vinyl chloride-vinyl-acetate copolymer, polyurethane, styrene butadiene copolymer, polycaprolactone, cellulose acetate butyrate, and combinations thereof;
b) from about 10% to about 30% by weight of glass fiber, based upon the total weight of the molding composition;
c) from 0.05% to 5% by weight of an initiator, based upon the total weight of the molding composition; and
d) from 250 to 450 pph of a flame retardant consisting of aluminum hydroxide, based on the weight of the thermoset resin system;
whereby the molding, composition when molded meets the standard of UL 723.
2. The component as set forth in claim 1 , wherein the molding composition further comprises a thickening agent comprising magnesium oxide or magnesium hydroxide.
3. The component as set forth in claim 1 , wherein the molding composition further comprises an antimicrobial agent.
4. The component as set forth in claim 1 , wherein the low profile additive is a saturated polyester present in an amount of from about 35% to about 45% by weight of the thermoset resin system.
5. The component as set forth in claim 4 , wherein said reactive monomer comprises hydroxyethyl methacrylate and styrene and wherein the molding composition comprises not more than 10% by weight of styrene, based on the weight of the molding composition.
6. The component as set forth in claim 1 , wherein the glass fiber comprises from about 15% to about 25% by weight, based upon the total weight of the molding composition.
7. The component as set forth in claim 6 , wherein the component is a drain pan, a base pan, or a blower housing.
8. A method of making a component for an air handler or hot air furnace comprising molding a housing from a molding composition, the molding composition comprising:
a) a thermoset resin system comprising: an unsaturated polyester prepolymer and a reactive monomer;
wherein the unsaturated polyester prepolymer has a weight average molecular weight of from 200 to 5,000 and a glass transition temperature of from 150° C. to 175° C.;
wherein the unsaturated polyester prepolymer is dissolved in the reactive monomer;
wherein the unsaturated polyester prepolymer is-a product of a condensation polymerization reaction between a polyol and an acid, anhydride, acid dimer or anhydride dimer;
where the polyol is selected from the group consisting of ethylene glycol, propylene glycol, neopentyl glycol, diethylene glycol, dipropylene glycol, trimethylpentanediol, cyclohexane diol, propoxylated bisphenol A, hydrogenated bisphenol A, and combinations thereof;
wherein the acid, anhydride, acid dimer or anhydride dimer is selected from the group consisting of phthalic anhydride, maleic anhydride, adipic acid, isophthalic acid, orthophthalic acid, terephthalic acid, fumaric acid, glutaric acid, azelaic acid, endomethylenetetrahydrophthalic anhydride, and combinations thereof;
wherein the reactive monomer comprises hydroxyethyl methacrylate, and optionally a monomer selected from the group consisting of styrene, α-methyl styrene, vinyl toluene, divinyl benzene, diallylphthalate, methyl methacrylate, and combinations thereof; and
wherein the unsaturated polyester prepolymer is cross-linked during molding with a low profile additive selected from the group consisting of polymethylmethacrylate, polyethylmethacrylate, polystyrene, polystyrene copolymer, polyvinyl acetate, polyethylene, saturated polyester, vinyl chloride-vinyl acetate copolymer, polyurethane, styrene butadiene copolymer, polycaprolactone, cellulose acetate butyrate and combinations thereof;
b) from about 10% to about 30% percent by weight of glass fiber, based upon the total weight of the molding composition;
c) an initiator; and
d) from 250 to 450 pph of a flame retardant comprising aluminum hydroxide, based on the weight of the thermoset resin system;
whereby the molding composition when molded meets the standard of UL 723.
9. The method of making a component as set forth in claim 8 , wherein the reactive monomer comprises hydroxyethyl methacrylate and styrene or toluene and the low profile additive is a saturated polyester.
10. The method of making a component as set forth in claim 8 , wherein the molding composition further comprises an antimicrobial agent.
11. A molding composition comprising:
a) a thermoset resin system comprises an unsaturated polyester prepolymer and a reactive monomer;
wherein the unsaturated polyester prepolymer has a weight average molecular weight of from 200 to 5,000 and a glass transition temperature of 150° C. to 175° C.;
wherein the unsaturated polyester prepolymer is dissolved in a reactive monomer;
wherein the unsaturated polyester prepolymer is a product of a condensation polymerization reaction between a polyol and an acid, anhydride, acid dimer or anhydride dimer;
where the polyol is selected from the group consisting of ethylene glycol, propylene glycol, neopentyl glycol, diethylene glycol, dipropylene glycol, trimethylpentanediol, cyclohexane diol, propoxylated bisphenol A, hydrogenated bisphenol A, and combinations thereof;
wherein the acid, anhydride, acid dimer or anhydride dimer is selected from the group consisting of phthalic anhydride, maleic anhydride, adipic acid, isophthalic acid, orthophthalic acid, terephthalic acid, fumaric acid, glutaric acid, azelaic acid, endomethylenetetrahydrophthalic anhydride, and combinations thereof;
wherein the reactive monomer comprises hydroxyethyl methacrylate, and optionally a monomer selected from the group consisting of styrene, α-methyl styrene, vinyl toluene, divinyl benzene, diallylphthalate, methyl methacrylate, and combinations thereof; and
wherein the unsaturated polyester prepolymer is cross-linked during molding with a low profile additive selected from the group consisting of polymethylmethacrylate, polyethylmethacrylate, polystyrene, polystyrene copolymer, polyvinyl acetate, polyethylene, saturated polyester, vinyl chloride-vinyl acetate copolymer, polyurethane, styrene butadiene copolymer, polycaprolactone, cellulose acetate butyrate and combinations thereof;
b) from about 10% to about 30% percent by weight of glass fiber, based upon the total weight of the molding composition;
c) an initiator; and
d) from 250 to 450 pph of a flame retardant comprising aluminum hydroxide, based on the weight of the thermoset resin system;
whereby the molding composition when molded meets the standard of UL 723.
12. The molding composition as set forth in claim 11 , wherein the reactive monomer comprises hydroxyethyl methacrylate and styrene or toluene and the low profile additive is a saturated polyester.
13. The molding composition as set forth in claim 11 , wherein the amount of glass fiber is from about 15% to about 25% weight, based upon the total weight of the molding composition.
14. The molding composition as set forth in claim 11 , further comprises an antimicrobial agent.