Molding compounds for use in furnace blower housings and blower housings molded from these compounds
View Patent ↗The invention provides blower housings for air handlers and hot air furnaces which are made from molding compounds that allow for wide flexibility in molding complex configurations so as to improve blower efficiency, which improve manufacturing efficiency and safety and provide suitable mechanical properties, safety in use, and sound dampening. These compounds are generally liquid thermosetting molding resins which comprise a thermoset resin matrix such as a isophthalate polyester having a specific loading of glass reinforcing fibers. The compositions also include flame retardant additives. They are further formulated to meet the desired molding characteristics; to withstand the operating temperatures to which they will be exposed; and to have a predetermined strength and a desirable user interface including appearance, and odor. Typically, the compounds will have a glass transition temperature from about 160° C. (320° F.) to about 185° C. (365° F.).
1. A method of making a blower housing for an air handler or hot air furnace comprising molding the housing from a composition comprising:
a) an unsaturated prepolymer resin which comprises a polyester isophthlate;
b) an unsaturated material copolymerizable with said resin and including a terminal ethylene group;
c) from about 10 to about 25 percent by weight of glass fiber based upon the total weight of the composition;
d) an initiator to initiate said copolymerization; and
e) a flame retardant comprising antimony trioxide which is present in an amount from about 5 parts to about 20 parts by weight based upon 100 parts by weight of resin.
2. A method of making a blower housing as set forth in claim 1 wherein the amount of glass fiber is from about 15 to about 25 percent by weight based upon the total weight of the composition.
3. A method of making a blower housing as set forth in claim 1 wherein the amount of glass fiber is from about 18 to about 23 percent by weight based upon the total weight of the composition.
4. A method of making a blower housing for an air handler or hot air furnace comprising molding the housing from a composition comprising:
a) a polyester isophthlate resin;
b) an unsaturated material copolymerizable with said resin and including a terminal ethylene group;
c) from about 60 to about 75 phr of glass fiber based upon the total weight of the resin which is the weight of a) and b);
d) an initiator to initiate said copolymerization; and
e) a flame retardant comprising antimony trioxide which is present in an amount of from about 5 parts to about 20 parts by weight based upon 100 parts by weight of resin.