Thickening agents
Invert water-in-silicone emulsions and a process of production thereof are disclosed. The invert water-in-silicone emulsion is based on polymerizing or copolymerizing one of an ionic, anionic, and/or cationic monomer, or a non-ionic monomer in the presence of a cross-linking agent and transfer agent. The emulsion comprises: a continuous phase having at least one silicone-type oil, and at least two surfactants, at least one of which is a water-in-silicone-type silicone emulsifier and at least one of which is an inversion agent.
1 . A “water-in-silicone” inverse emulsion produced by the process of:
polymerizing or copolymerizing at least one of an ionic monomer, an anionic monomer, a cationic monomer, or a non-ionic monomer in the presence of a cross-linking agent wherein the emulsion comprises:
(a) a continuous phase having at least one silicone-type oil; and
(b) at least two surfactants, at least one of which is a water-in-silicone-type silicone emulsifier and at least one of which is an inversion agent.
2 . The emulsion as claimed in claim 1 , wherein the cationic monomer is chosen from the group consisting of dialkylaminoalkyl (meth)acrylate, dialkylaminoalkyl (meth)acrylamide, diallylamine, methyldiallylamine, and a quaternary ammonium or acid salt thereof.
3 . The emulsion as claimed in claim 1 , wherein the anionic monomer is chosen from the group consisting of acrylic acid, methacrylic acid, 2-acrylamido-2-methyl propane sulphonic acid, and a salt thereof.
4 . The emulsion as claimed in claim 1 , wherein the non-anionic monomer is chosen from the group consisting of acrylamide, methacrylamide, N-vinyl pyrrolidone, vinyl acetate, vinyl alcohol, acrylate ester, and allyl alcohol.
5 . The emulsion as claimed in claim 1 , wherein the non-ionic monomer is N-vinyl pyrrolidone.
6 . The emulsion as claimed in claim 1 , wherein the cross-linking agent is chosen from the group consisting of methylene bisacrylamide, ethylene glycol diacrylate, polyethylene glycol dimethacrylate, diacrylamide, cyanomethyl acrylate, vinyl oxyethyl (meth)acrylate, formaldehyde, glyoxal, glycidyl ether and epoxy.
7 . The emulsion as claimed in claim 1 additionally comprising a transfer agent.
8 . The emulsion as claimed in claim 7 , wherein the transfer agent is chosen from the group consisting of isopropyl alcohol, sodium hypophosphite, and mercaptoethanol.
9 . The emulsion as claimed in claim 1 , wherein the concentration of active matter during polymerization is from 20% by weight (wt %) to 50 wt %.
10 . The emulsion as claimed in claimed 1 , wherein the water-in-silicone-type silicone emulsifier is non-ionic.
11 . The emulsion as claimed in claim 1 , wherein the inversion agent has a mean hydrophilic/lipophilic balance (HLB) value greater than 8 and is chosen from the group consisting of a fatty alcohol ethoxylate, a fatty acid ester, sorbitan, a polyethylene glycol, glycerol, alkyl polyglycoside, and a dimethicone copolyol.
12 . The emulsion as claimed in claim 1 , wherein a cross-linking rate of polymerization or copolymerization is greater than 10 ppm in relation to a polymer formed when the cross-linking agent is methylene bisacrylamide.
13 . The emulsion as claimed in claim 1 , wherein polymerization or copolymerization occurs in the presence of at least one non-water-soluble monomer selected from the group consisting of an acrylic monomer, allylic monomer, and a vinylic monomer each having a hydrophobic substituent attached.
14 . The emulsion as claimed in claim 1 , wherein the water-in-silicone-type silicone emulsifier is chosen from the group consisting of a dimethicone copolyol, a silicone alkanolamide, a silicone ester, and a silicone glycoside.
15 . The emulsion as claimed in 1 , wherein a cross-linking rate of polymerization or copolymerization is greater than 50 ppm in relation to a polymer formed when the cross-linking agent is methylene bisacrylamide.
16 . The emulsion as claimed in claim 1 , wherein a cross-linking rate of polymerization or copolymerization is greater than 200 ppm in relation to a polymer formed when the cross-linking agent is methylene bisacrylamide.
17 . A method for making a “water-in-silicone” inverse emulsion comprising:
providing an aqueous solution having at least one of an ionic monomer, an anionic monomer, a cationic monomer, or a non-ionic monomer, and a cross-linking agent;
providing an oil-based solution having at least one silicone-type oil and at least two surfactants, at least one of which is a water-in-silicone-type silicone emulsifier and at least one of which is an inversion agent; and
mixing the aqueous solution and the oil-based solution to form the “water-in-silicone” inverse emulsion having at least one of the silicone-type oil in a continuous phase within the inverse emulsion.