GB492320A - Improvements in or relating to the solidification or thickening of organic liquids - Google Patents

Abstract

Solid fuels, paint removers, &c. are obtained by dissolving a polymer or interpolymer, containing saponifiable groups and derived from compounds containing the group CH2 = C<, in an organic liquid which is a non-solvent for the saponified product and treating to saponify a number of saponifiable groups which is one-third or less of the number of polymerizable monomeric molecules from which the polymer or interpolymer was derived so as to give a stable gel. Small additions of solvent liquids, e.g. alcohol and acetone may be made. Suitable polymers and interpolymers are those derived from acrylic acid esters, acrylic acid nitrile, maleic acid and vinyl esters. Saponification may be effected with aqueous caustic soda or potash, sodium or potassium alcoholate, and acids, e.g. hydrochloric or sulphuric; with polyvinyl esters the saponification is controlled to give a stable gel. With interpolymers containing non-saponifiable groups, e.g. that derived from 25 parts acrylic acid methyl ester and 75 parts styrol, the saponifiable groups may be completely saponified. Liquids which may be thickened include methylene chloride, higher alcohols from butyl upwards, benzine and mineral oils, ethyl acetate and benzene. The gels produced do not melt on warming and may be worked up mechanically with other solvents to form paste-like, thickly-fluid materials. In examples: (1) methylene chloride containing 1/2 per cent of polyacrylic acid ethyl ester is treated with 1/2 per cent normal alcoholic caustic soda, forming a stable gel after a few hours; benzene similarly solidified can be packed in tubes and used as a solid fuel; (2) polyacrylic acid methyl ester, dissolved in a mixture of naphthalene, tetrahydronaphthalene, methylene chloride and dipentene is saponified with alcoholic caustic soda and the gel formed is mixed in an emulsifying machine with further solvents, e.g. ethyl acetate, acetone, methyl ethyl ketone to form a viscous mass suitable as a paint remover; (3) a solid fuel is produced by treating with normal caustic soda a solution of polyacrylic acid butyl ester in benzene; an interpolymer derived from, (4) 70 parts styrol and 30 parts acrylic acid methyl ester, or (5) 50 parts vinyl acetate and 50 parts methacrylic acid ethyl ester, is dissolved in benzene and treated with caustic soda. The Specification as open to inspection under Sect. 91 describes also the thickening of organic liquids by saponification of a cellulose ester, e.g. cellulose tripropionate, dissolved therein. This subject-matter does not appear in the Specification as accepted.ALSO:Solid fuels, paint removers, &c. are obtained by dissolving a polymer or interpolymer, containing saponifiable groups and derived from compounds containing the group CH2= C<, in an organic liquid which is a non-solvent for the saponified product, and treating to saponify a number of saponifiable groups which is one-third or less of the number of polymerizable monomeric molecules from which the polymer or interpolymer was derived, so as to give a stable gel. Small additions of solvent liquids, e.g. alcohol and acetone may be made. Suitable polymers and interpolymers are those derived from acrylic acid esters, acrylic acid nitrile, maleic acid and vinyl esters. Saponification may be effected with aqueous caustic soda or potash, sodium or potassium alcoholate, and acids, e.g. hydrochloric or sulphuric; with polyvinyl esters the saponification is controlled to give a stable gel. With interpolymers containing nonsaponifiable groups, e.g. that derived from 25 parts acrylic acid methyl ester and 75 parts styrol, the saponifiable groups may be completely saponified. Liquids which may be thickened include methylene chloride, higher alcohols from butyl upwards, benzine and mineral oils, ethyl acetate and benzene. The gels produced do not melt on warning and may be worked up mechanically with other solvents to form paste-like thickly fluid materials. In examples, (1) methylene chloride containing 1/2 per cent of polyacrylic acid ethyl caustic soda, forming a stable gel after a few hours; benzene similarly solidified can be packed in tubes and used as a solid fuel; (2) polyacrylic acid methyl ester, dissolved in a mixture of naphthalene, tetrahydronaphthalene, methylene chloride and dipentene is saponified with alcoholic caustic soda and the gel formed is mixed in an emulsifying machine with further solvents, e.g. ethyl acetate, acetone, methyl ethyl ketone, to form a viscous mass suitable as a paint remover; (3) a solid fuel is produced by treating with normal caustic soda a solution of polyacrylic acid butyl ester in benzene; an interpolymer derived from (4) 70 parts styrol and 30 parts acrylic acid methyl ester, or (5) 50 parts vinyl acetate and 50 parts methacrylic acid estyl ester, is dissolved in benzene and treated with caustic soda. The Specification as open to inspection under Sect. 91 describes also the thickening of organic liquids by saponification of a cellulose ester, e.g. cellulose tripropionate, dissolved therein. This subject-matter does not appear in the Specification as accepted.