Patent GB-983133-A (GB)
Title: Polyvinyl acetate coating compositions
IPC: C09D131/04
Filed: 1963-03-19
Abstract: A basecoat coating composition comprises, as the essential film-forming components, a vinyl acetate polymer containing at least 80% vinyl acetate and nitrocellulose in the proportion of from 4 to 20 parts per 100 parts of the vinyl acetate polymer, in a solution in a balanced volatile organic diluent composition constituting at least 70% by weight of the liquid coating composition, said diluent composition in 100 parts by weight thereof consisting essentially of (a) at least 50 parts of a fast evaporating mutual solvent for the nitrocellulose and polyvinyl acetate, the evaporation rate being greater than that of toluol, (b) from 0 to 20 parts of a slower evaporating liquid which is at least a solvent for the polyvinyl acetate and is characterized by an evaporation rate comparable with that of the non-solvent hydrocarbon components (c) from 0.3 to 25 parts of a C1 to C4 alkanol, and (d) from 20 to 40 parts of a non-solvent aromatic hydrocarbon having a rate of evaporation ranging from that of toluol to that substantially comparable with industrial 10 DEG  C. xylol, the weight ratio of (d)/(a)+(b) being from 0.25 to 0.8.  Preferably the nitrocellulose has a nitrogen content of from 11.7% to 12.2% and a viscosity of from 1/2 sec. to 500 secs. and is present in a proportion of from 0.7% to 3% by weight of the entire composition, the polyvinyl acetate has a viscosity of 5 to 150 centipoises, determined on a 9.6% benzene solution at 20 DEG  C. and the composition contains 12 to 25% of organic film-forming materials. Specified fast evaporating mutual solvents include acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, methyl acetate, ethyl acetate, isopropyl acetate, and n-propyl acetate.  Specified slower evaporating liquids include methyl n-amyl ketone, methyl isoamyl ketone, cyclohexanone, isobutyl acetate and n-butyl acetate. Specified C1-C4 alkanols includes ethyl and isopropyl alcohols. Nonsolvent hydrocarbons specified include toluol, xylol, industrial 10 DEG  C. xylol and petroleum naphthas of high aromatic content, boiling at 90-150 DEG  C.  A fluid organic polysiloxane having methyl or phenyl pendant substituents joined to silicon atoms, preferably polydimethylsiloxane may be present in a proportion by weight of from 100 parts to 1500 parts per million parts by weight of the organic film-forming constituents, together with conventional pigments, dyes or lakes.  In a preferred composition, the organic diluent may comprise by weight:-(a) 50 to 75 parts of the fast evaporating mutual solvent, (b) 0-10 parts of the slower evaporating liquid, (c) 5 to 20 parts of the C1 to C4 alkanol, and (d) from 20 to 35 parts of the non-solvent aromatic hydrocarbons.  The non-solvent aromatic hydrocarbons in 100 parts by weight of the coating composition may consist essentially of hydrocarbons substantially equivalent to 20 to 40 parts by weight of toluol and 80 to 60 parts by weight of industrial 10 DEG  C. xylol, said hydrocarbons having a boiling range of 90-150 DEG  C.  The mutual solvent (a) may consist of solvent substantially equivalent in solvency and evaporation rate to that of methyl ethyl ketone, the alkanol (c) may consist essentially of ethanol, and the non-solvent hydrocarbon (d) may consist essentially of 20 to 40 parts of toluol and 80 to 60 parts of industrial 10 DEG C. xylol for a total of 100 parts by weight of said hydrocarbon mixture.  A topcoat layer suitable for application over the above basecoat may consist of nitrocelluloses and a non-drying fatty oil acid ester plasticizer in the proportion by weight of 20 to 150 parts per 100 parts of nitro-cellulose, preferably of 1/4 to 3/4 sec. nitrocelluloses with a plasticizing ester, the fatty acid component of which is ricinoleic acid.  Castor oil modified glyceryl phthalate alkyd resins and a castor oil modified polyester of ethylene glycol and sebacic acid may be used.  Preferably 20 to 35 parts of a C1 to C4 alkyl acetyl ricinoleate especially butyl acetyl ricinoleate are used per 100 parts of the nitrocellulose, and the topcoat layer may also contain a polyorganosiloxane having methyl or phenyl pendant substituents joined to silicon atoms, in a proportion of from 200 to 1000 parts per million parts of the organic film-forming components of the coating composition.ALSO:A wood substrate, e.g. a bowling alley or wooden floor, is coated with a basecoat coating composition which comprises, as the essential film-forming components, a vinyl acetate polymer containing at least 80% vinyl acetate and nitrocellulose in the proportion of from 4 to 20 parts per 100 parts of the vinyl acetate polymer, in a solution in a balanced volatile organic diluent composition constituting at least 70% by weight of the liquid coating composition, said diluent composition in 100 parts by weight thereof consisting essentially of (a) at least 50 parts of a fast evaporating mutual solvent for the nitrocellulose and polyvinyl acetate, the evaporation rate being greater than that of toluol, (b) from 0 to 20 parts of a slower evaporating liquid which is at least a solvent for the polyvinyl acetate and is characterized by an evaporation rate comparable with that of the non-solvent hydrocarbon components, (c) from 0,3 to 25 parts of a C1-C4 alkanol, and (d) from 20 to 40 parts of a non-solvent aromatic hydrocarbon having a rate of evaporation ranging from that of toluol to that substantially comparable with industrial 10 DEG C. xylol, the weight ratio of (d)/(a)+(b) being from 0,25 to 0,8.  Preferably the nitrocellulose has a nitrogen content of from 11,7% to 12,2% and a viscosity of from 1/2 sec. to 500 secs. and is present in a proportion of from 0,7% to 3% by weight of the entire composition, the polyvinyl acetate has a viscosity of 5-150 centipoises, determined on a 9,6% benzene solution at 20 DEG C. and the composition contains 12-25% of organic film-forming materials. Specified fast evaporating mutual solvents include acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, methyl acetate, ethyl acetate, isopropyl acetate, and n-propyl acetate.  Specified slower evaporating liquids include methyl n-amyl ketone, methyl isoamyl ketone, cyclohexanone, isobutyl acetate and n-butyl acetate. Specified C1-C4 alkanols include ethyl and isopropyl alcohols. Non-solvent hydrocarbons specified include toluol, xylol, industrial 10 DEG C. xylol and petroleum naphthas of high aromatic content, boiling at 90-150 DEG C.  A fluid organic polysiloxane having methyl or phenyl pendant substituents joined to silicon atoms, preferably polydimethylsiloxane, may be present in a proportion by weight of from 100 parts to 1500 parts per million parts by weight of the organic film-forming constituents, together with conventional pigments, dyes or lakes.  In a preferred composition, the organic diluent may comprise by weight: (a) 50-75 parts of the fast evaporating mutual solvent, (b) 0-10 parts of the slower evaporating liquid, (c) 5-20 parts of the C1-C4 alkanol, and (d) from 20 to 35 parts of the non-solvent aromatic hydrocarbons.  The non-solvent aromatic hydrocarbons in 100 parts by weight of the coating composition may consist essentially of hydrocarbons substantially equivalent to 20-40 parts by weight of toluol and 80-60 parts by weight of industrial 10 DEG C. xylol, said hydrocarbons having a boiling range of 90-150 DEG C.  The mutual solvent (a) may consist of solvent substantially equivalent in solvency and evaporation rate to that of methyl ethyl ketone, the alkanol (c) may consist essentially of ethanol, and the non-solvent hydrocarbon (d) may consist essentially of 20-40 parts of toluol and 80-60 parts of industrial 10 DEG C. xylol for a total of 100 parts by weight of said hydrocarbon mixture.  The basecoat is dried at ambient temperature and a plurality of coats of nitrocellulose lacquer topcoat composition are applied over the resulting dry basecoat, and the topcoats dried at ambient temperature, the basecoat being applied at a coating weight substantially equivalent to one U.S. gallon of basecoat composition at about 20% film-forming solids content per lane area of 63 feet by 3,5 feet, and the total coating weight of the topcoat composition being from 1,5 to 4 times that of the basecoat.  The topcoat layer may consist of nitrocelluloses and a non-drying fatty oil acid ester plasticizer in the proportion by weight of 20-150 parts per 100 parts of nitrocellulose, preferably of 1/4 -\ba3/4 sec. nitrocelluloses with a plasticizing ester, the fatty acid component of which is ricinoleic acid.  Castor oil modified glyceryl phthalate alkyd resins and a castor oil modified polyester of ethylene glycol and sebacic acid may be used. Preferably 20-35 parts of a C1-C4 alkyl acetyl ricinoleate, especially butyl acetyl ricinoleate, are used per 100 parts of the nitrocellulose, and the topcoat layer may also contain a polyorganosiloxane having methyl or phenyl pendant substituents joined to silicon atoms, in a proportion of from 200 to 1000 parts per million parts of the organic film-forming components of the coating composition.