Dispersions of siliceous solids in liquid organic media
AssigneeImperial Chemical Industries PLC
InventorsJozef Nemcek, Thomas A. Roberts, Francis R. Sherliker
Life of this patent
Estimating the term…
Abstract
Dispersions of colloidal siliceous particles, preferably silica, may be prepared in organic liquids by means of a synergistic mixture of dispersing agents comprising a phosphorus oxy-acid derivatives and a long-chain amine. Dispersions containing a high weight fraction of siliceous solids are possible having a lower viscosity than is normally achieved.
Claims27
A composition comprising the following components (a-c) intimately mixed together
- (a) a particulate siliceous material having particles below 10 .mu.m in their longest dimension,
- (b) a liquid or liquifiable polymerizable organic medium,
- (c) a dispersing agent containing a mixture of compounds comprising a phosphorus oxyacid having the formula ##STR7## wherein R.sub.1 is an organic group containing a terminal chain which is either a hydrocarbon group having at least six carbon atoms or a polyether of molecular weight greater than 200 (preferably from 500-10,000) R.sub.2 is either a group as specified for R.sub.1, a hydrogen atom, or a hydrocarbyl or substituted hydrocarbyl group not having a terminal chain of at least six carbon atoms and an organic basic nitrogen compound having the formula ##STR8## wherein Z.sub.1 is a group as specified for R.sub.1 before and Z.sub.2 and Z.sub.3 which may be the same or different, are as specified for R.sub.2 before.
A dispersion as claimed in claim 20 wherein the silica has an average particle size below 1 .mu.m.
A dental composition which is a fluid composition comprising:
- (a) a particulate siliceous material having particles below 1 .mu.m in their longest dimension;
- (b) a liquid or liquifiable organic medium which is either a vinyl urethane or the reaction product of a bisphenol with a glycidyl alkacrylate
- (c) a dispersing agent containing a mixture of compounds comprising a phosphorus oxyacid having the formula:
- ##STR9## where R.sub.1 is an organic group containing a terminal chain which is either a hydrocarbon group having at least six carbon atoms or a polyether of molecular weight greater than 200, preferably from 500-10,000, R.sub.2 is either a group as specified for R.sub.1, a hydrogen atom, or a hydrocarbyl or substituted hydrocarbyl group not having a terminal chain of at least six carbon atoms and an organic basic nitrogen compound having the formula:
- ##STR10## wherein Z.sub.1 is a group as specified for R.sub.1 before and Z.sub.2 and Z.sub.3, which may be the same or different, are as specified for R.sub.2 and
- (d) a free radical generative catalyst for polymerisation of the organic medium.
A composition comprising the following components (a-c) intimately mixed together
- (a) a particulate siliceous material having particles below 10 .mu.m in their longest dimension,
- (b) a liquid or liquifiable polymerizable organic medium not containing acidic or basic groups,
- (c) a dispersing agent containing a mixture of compounds comprising a phosphorus oxyacid having the formula ##STR12## wherein R.sub.1 is an organic group containing a terminal chain which is either a hydrocarbon group having at least six carbon atoms or a polyether of molecular weight greater than 200 (preferably from 500-10,000) R.sub.2 is either a group as specified for R.sub.1, a hydrogen atom, or a hydrocarbyl or substituted hydrocarbyl group not having a terminal chain of at least six carbon atoms and an organic basic nitrogen compound having the formula ##STR13## wherein Z.sub.1 is a group as specified for R.sub.1 before and Z.sub.2 and Z.sub.3 which may be the same or different, are as specified for R.sub.2 before.
Dependencies are inferred from the claim text.