Polyvinyl chloride terpolymer powder coating composition

#This invention is related to powder coating compositions and in particular to a polyvinyl chloride containing powder coating composition.

#Power coating compositions are well known in the art and have been used in the place of conventional solvent and water-based paints to coat a variety of different substrates. Polyvinyl chloride powder coatings are broadly used and well known as shown by Richardson U.S. Pat. No. 3,842,027 issued Oct. 15, 1974. These polyvinyl chloride powder coatings are applied by conventional fluid bed or electrostatic spray techniques. However, these polyvinyl chloride powders agglomerate and lose free flow characteristics when exposed to heat and pressure in storage or in application equipment. When this occurs, additional sieving or mixing of the powder is required to achieve uniform application of the powder on substrates.

#Another deficiency of the polyvinyl chloride powders is that finishes of the powders have reduced impact and bend resistance particularly at low temperatures which may make the powders unacceptable for certain end uses.

#The following example illustrates the invention. All quantities are on a weight basis unless otherwise indicated.

#The following ingredients are blended together:

#______________________________________ Parts by Weight ______________________________________ Polyvinyl chloride terpolymer (vinyl chloride/- vinyl acetate/maleic anhydride polymer in a weight ratio of 80/20/1 and having a weight average molecular weight of 65,000) 100.0 Plasticizer Resin (ethylene/vinyl acetate/- carbon monoxide polymer weight ratio of 66/23/11 and a weight average molecular weight of about 250,000) 25.0 Liquid epoxy resin (epoxyhydroxy polyether resin of epichlorohydrin and bisphenol A having an epoxide equivalent of 182-190 and a viscosity of 11,000-14,000 centi- poise at 25.degree. C and a molecular weight of about 364-380) 5.0 Butyl tin mercaptide (a mixture of mono- butyl tin mercaptide and dibutyl tin mercap- tide having a tin content of about 23.5% and a sulfur content of about 10.5%) 3.0 "Bareco" polywax 2000 (low molecular weight polyethylene wax) 0.5 Ultraviolet light-absorbing agent 2,4-di-t-butyl phenyl 3,5-di-t-butyl- 4hydroxy benzoate. 0.5 Total 134.0 ______________________________________