Chlorinated polyvinyl chloride composition
AssigneeThe B. F. Goodrich Company
InventorsSamuel D. Nehmey, James W. Summers
Life of this patent
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Abstract
Composition of matter adapted to be foamed into essentially a closed cell structure, preponderance of the cells being less than 500 microns in size and containing a chlorofluoroalkane of 1 to 2 carbon atoms, said composition comprising chlorinated polyvinyl chloride resin, and effective amount of a blowing agent, an effective amount of a nucleating agent, and 5 to 20 parts of a processing aid per 100 parts of said resin, said processing aid has a dilute solution viscosity of greater than 2.5 and is selected from copolymers of styrene and acrylonitrile containing 10 to 40% of acrylonitrile.
Claims10
Composition of matter adapted to be foamed comprising chlorinated polyvinyl chloride resin containing at least 60% chlorine by weight, an effective amount of a blowing agent to cause said resin to foam, an effective amount of a nucleating agent for providing nucleating sites for forming cells filled with said blowing agent, and 1 to 30 parts by weight of a processing aid per 100 parts by weight of said resin, said processing aid has a Tg of greater than 60.degree. C., has dilute solution viscosity greater than 1.5, and is selected from copolymers of a styrene and an unsaturated nitrile containing more than 50% of said styrene and 10 to 40% of said nitrile.
A rigid, nonflammable, thermoplastic foam in which at least 60% of the cells are closed, said foam having a density of less than 5 lbs/ft.sup.3, thermal conductivity of less than 0.20 Btu/(hr) (ft.sup.2)(.degree.F./in), and a chlorofluoroalkane of 1 to 2 carbon atoms trapped in the closed cells, said foam comprising chlorinated polyvinyl chloride having a glass transition temperature of at least about 105.degree. C. and a chlorine content of at least 64%, 0.01 to 2 parts of azodicarbonamide nucleating agent dispersed therein forming the nuclei for the cells, and 5 to 20 parts of a hard, glassy processing and having a dilute solution viscosity greater than 2.5 selected from copolymers of styrene and acrylonitrile containing 10 to 40% acrylonitrile.
Method for making a foam product comprising feeding into an extruder powdered chlorinated polyvinyl chloride composition, melting said composition as it is advanced through the extruder, injecting a blowing agent into said melted composition, mixing said composition and said blowing agent to more uniformly distribute said blowing agent in said composition, and then forcing said composition into a zone of lower pressure whereby said blowing agent expands to form the foam product in which at least 85% of the cells are closed cells, preponderance of the cells are less than 500 microns, its density is less than 5 lbs/ft.sup.3, and its thermal conductivity is less than 0.20 Btu/(hr) (ft.sup.2)(.degree.F./in), said composition comprising chlorinated polyvinyl chloride resin having a glass transition temperature of at least 105.degree. C. and a chlorine content of at least 64%, 0.01 to 2 parts by weight of a nucleating agent dispersed therein forming nuclei for the cells, and 1 to 30 parts by weight of a hard glassy processing aid selected from copolymers of a styrene and a nitrile containing 10 to 40% nitrile, having dilute solution viscosity greater than 1.5.
Dependencies are inferred from the claim text.