| abstract |
Paints and varnishes are made contg. (by wt.) 15.0-81.2% of an organic binder, 0.04-3.0% of an organosiloxane-oxyalkylene copolymer and the remainder to 100% of a solvent. The organosiloxane-oxyalkylene copolymer has formula (I) in which R is CH3 or C2H5; R' is CH3, CH3CO, CH3CO, H or C2H5; A is (CH2)y; y is 1-3; n is 2-3; m is 5-30, and the compsn. has a mole wt. of 500-2000. The (I) can beused with a wide variety of binders, including unsatd. polyesters, polyurethanes, polyacrylates, nitrocellulose, alkyds, phenolic resins, epoxy resins, vinyl copolymers, urea- and melamine-formaldehyde resins, etc. (I) are prepd. by addn. of an organosiloxane (CH3)3-Si-(-O-Si(R)(H)-)-O-Si(CH3)3 with an alipha-omega allyloxyalkyloxyprolyoxyalkylene glycol CH2:CH-CH2-(-O-CnH2n-)m-OR' in the presence of a Pt caralyst. The compsn. may also contain a photoinitiator, a hardener, an accelerator, a primer, a thixotropic agent, a plasticiser, a pigment and a filler. The additives (I) give smooth, blemish-free coatings free from bubbles, craters, fissures, etc., and reduce demixing effects in paints etc. on storage. |