within the following ranges will be quite satisfactory for use in carrying out the invention table ii______________________________________water 70 to 95 polyvinyl alcohol 1 to 10 glycol 1 to 30 preservatives 0 to 5 flatting agents etc ______________________________________ the glycol plasticizer is preferably glycerol ethylene glycol or mixtures of glycerol and ethylene glycol and is present in a ratio of from 1 to four times the amount of polyvinyl alcohol mixtures of these glycols generally comprise from 1 to 2 parts of ethylene glycol for each part of glycerol it has been found that a particular blend of polyvinyl alcohols is especially advantageous this blend comprises from about 0 5 to 2 parts of a fully hydrolyzed hot water soluble cold water insoluble polyvinyl alcohol having a high viscosity of 55 65 cps in 4 aqueous solution air products and chemicals inc 34 vinol 165 34 trademark and from 0 5 to 2 parts of a fully hydrolyzed hot water soluble cold water insoluble polyvinyl alcohol having a medium viscosity of 27 33 cps in 4 aqueous solution dupont company 34 elvanol 71 30 34 trademark in a solution of from about 1 to 2 to about 6 typically about 4 in water with about three times as much glycol i e from about 3 to about 18 glycol preferably a blend of about 1 25 parts of ethylene glycol to each part of glycerol a mixture as indicated above is formed as a slurry and.