Powder coating compositions
A powder coating composition comprises a mixture, in particulate form, of a zeolite and an organic resin, said zeolite containing less than 9 percent water by weight as determined by heating at 800° C. for 1 hour. The zeolite can act as an extender for titanium dioxide in systems containing the latter.
1 . The use in a powder coating composition comprising a mixture, in particulate form, of titanium dioxide and an organic resin, of a zeolite as an extender for the titanium dioxide, said zeolite containing less than 9 percent water by weight as determined by heating at 800° C. for 1 hour.
2 . A powder coating composition comprising a mixture, in particulate form, of a zeolite and an organic resin, said resin being a plasticised poly(vinyl chloride), a polyamide, poly(vinylidene fluoride), an epoxy resin, a polyester resin, a hybrid epoxy-polyester resin, a urethane resin or an acrylic resin and said zeolite containing less than 9 percent water by weight as determined by heating 800° C. for 1 hour.
3 . The use or composition according to claim 1 , wherein the zeolite is a zeolite A or a zeolite P.
4 . The use or composition according to claim 1 , wherein the zeolite contains less than 7 percent by weight water, as determined by heating at 800° C. for 1 hour.
5 . The use or composition according to claim 1 , wherein the zeolite has a water loss after heating at 105° C. for 4 hours of less than 2 percent by weight.
6 . The use or composition according to claim 1 , wherein the zeolite has a weight mean particle size in the range 0.5 μm to 6.0 μm.
7 . The use or composition according to claim 1 , wherein the powder coating composition additionally comprises from 10 to 40 percent by weight pigmentary titanium dioxide.
8 . The use or composition according to claim 7 , wherein the amount of zeolite present is up to 20 percent by weight of the coating composition.
9 . The use or composition according to claim 1 , wherein the powder coating composition additionally contains a colored pigment and from 2 to 20 weight percent pigmentary titanium dioxide.
10 . The use or composition according to claim 9 , wherein the amount of zeolite present in the composition is from 0.5 to 8 percent by weight of the coating composition.
11 . The use or composition according to claim 1 , wherein the particles of the powder coating composition have an average size in the range 10 to 75 μm.
12 . The use or composition according to claim 1 , wherein the particles of the powder coating composition have an average size in the range 40 to 200 μm.
13 . The use according to claim 1 in which the organic resin is plasticised poly(vinyl chloride), a polyamide, a polyolefin, poly(vinylidene fluoride), an epoxy resin, a polyester resin, a hybrid epoxy-polyester resin, a urethane resin or an acrylic resin.
14 . A method of preparing a powder coating composition comprising forming an intimate mixture of an organic resin and a zeolite, said resin being a plasticised poly(vinyl chloride), a polyamide, poly(vinylidene fluoride), an epoxy resin, a polyester resin, a hybrid epoxy-polyester resin, a urethane resin or an acrylic resin and said zeolite contains less than 9 percent water by weight as determined by heating at 800° C. for 1 hour.