Among the solvents that are suitable for use, mention may be made of alcohols such as ethyl alcohol, isopropyl alcohol, benzyl alcohol, and phenylethyl alcohol; glycols; glycol ethers, for instance ethylene glycol monomethyl ether; monoethyl ether; monobutyl ether; propylene glycol and ethers thereof, for instance propylene glycol monomethyl ether; butylene glycol; dipropylene glycol; diethylene g