GB665083A - Production of stable concentrated aqueous emulsions - Google Patents

Abstract

Concentrated emulsions which may subsequently be diluted with water or organic solvents are prepared by incompletely distilling off water and solvent from an oil-in-water emulsion such as described in Specification 645,023 in which the internal phase consists of an easily emulsifiable solution in a water-immiscible solvent, preferably an alcohol, of a water-insoluble hardenable condensate obtained from formaldehyde, a substance of amide character such as urea, thiourea, guanidine, biuret, dicyandiamide or melamine, and a water-immiscible alcohol, and of which the external phase consists of an aqueous solution containing, in addition to one protein as, such casein or gelatine, urea, thiourea or a mixture thereof. Suitable alcohols are butyl, amyl, hexyl, cyclohexanol or benzyl alcohol. The distillation is preferably effected under reduced pressure with vigorous agitation; if desired, water or a different organic solvent may be added before, during, or after distillation. Softening agents, filling materials, waxes and pigments may be added to the organic solvent constituting the inner phase, which solvent may be aliphatic or cyclic hydrocarbons, higher alcohols, ethers, esters, ketones or nitrobenzene. Additions to the aqueous phase may be emulsifying agents, softeners such as glycerine or polyglycol, hardening catalysts, filling or matting agents, pigments or buffers. Examples relate to the distillation of emulsions containing as the internal phase urea-formaldehyde-butanol resin, dissolved in butanol, an urea-formaldehyde condensate etherified with butanol and free from uncombined butanol and dissolved in metaxylene or a mixture of monochlorobenzene and ethyl alcohol, a melamine formaldehyde butanol resin dissolved in butanol, a urea/thiourea formaldehyde condensate modified with cyclohexanol, and a urea-formaldehyde condensate modified with 2-ethylhexanol dissolved in a mixture of 2-ethylhexanol and toluene. Specifications 597,390 and 650,977 also are referred to.ALSO:Concentrated emulsions which may subsequently be diluted with water or emulsified with organic solvents are prepared by incompletely distilling off water and solvent from an oil in water emulsion such as described in Specification 645,023 in which the internal phase consists of an easily emulsified solution in a water immiscible organic solvent, preferably an alcohol, of a water insoluble hardenable condensate obtained from formaldehyde, a substance of amide character such as urea, thiourea, guanidine, biuret, dicyandiamide or melamine and a water immiscible alcohol, and of which the external phase consists of an aqueous solution containing in addition to one protein such as acid casein or gelatine, urea, thiourea or a mixture thereof. Suitable alcohols are butyl, amyl, hexyl cyclohexanol or benzyl alcohol. The distillation is preferably effected under reduced pressure with vigorous agitation and if desired, water or a different organic solvent may be added before, during, or after distillation. Softening agents, filling materials, waxes and pigments may be added to the organic solvent constituting the inner phase, which solvent may be aliphatic or cyclic hydrocarbons, higher alcohols, ethers, esters, ketones or nitrobenzene. Additions to the aqueous phase may be emulsifying agents, softeners such as glycerine or polyglycol, hardening catalysts, filling or matting agents, pigments and buffers. Examples relate to the distillation of emulsions containing the internal phase urea-formaldehyde butanol resin dissolved in butanol, an urea-formaldehyde condensate etherified with butanol freed from uncombined butanol and dissolved in metaxylene, or a mixture of monochlorobenzene and ethyl alcohol, a melamine formaldehyde butanol resin dissolved in butanol, an urea/thiourea formaldehyde condensate modified with cyclohexanol, and an urea formaldehyde condensate modified with 2-ethylhexanol dissolved in a mixture of 2-ethylhexanol and toluene. Specifications 597,390, [Group IV], and 650,977 also are referred to.