COMPOSITIONS FOR HIGH STABILIZATION OF EMULSIONS

Abstract

The instant invention concerns compositions suitable for stabilizing emulsions, which comprise a mixture of:—at least an alkanolamide emulsifier; and—a block copolymer comprising:—a hydrophilic block comprising units deriving from a mono-alpha-ethylenically-unsaturated monomers; and—a block B preferably deriving from a mono-alpha-ethylenically-unsaturated monomers

Claims

1. A composition C comprising a mixture of: at least an alkanolamide emulsifier; and a block copolymer comprising: a block A which is a hydrophilic block comprising units derived from mono-alpha-ethylenically-unsaturated monomers; and a block B which is a hydrophobic block.

2. The composition of claim 1, wherein the ratio copolymer/alkanolamide corresponding to the quotient of the total mass of copolymer contained in composition C, to the total mass of the alkanolamide emulsifier contained in composition C is between 1% and 40%.

3. The composition of claim 1, wherein the alkanolamide emulsifier is a compound having the Formula (I) below:
R.sup.1—C(═O)—N[—(R.sup.2O).sub.xH)][—(R.sup.3O).sub.yH]  (I) wherein: R.sup.1 is an hydrocarbon chain bearing typically from 5 to 24 carbon atoms, each of R.sup.2 and R.sup.3, which are the same or not, is a hydrocarbon chain bearing from 2 to 4 carbon atoms, each of x and y, which are the same or not, are of is between 1 and 5.

4. The composition of claim 3, wherein the alkanolamide emulsifier is a compound having the Formula (Ia) or (Ib) below:
R.sup.1—C(═O)—N(R.sup.2OH)(R.sup.3OH)   (Ia)
R.sup.1—C(═O)—N(R.sup.2OH).sub.2   (Ib) wherein R.sup.1, R.sup.2 and R.sup.3 are as defined in claim 3.

5. The composition of claim 1, wherein the block copolymer is a (block A)-(block B) di-block copolymer.

6. The composition of claim 1, wherein the block A of the block copolymer comprises repeating units deriving from N-vinyl pyrrolidone, acrylamide and/or N,N-Dimethylacrylamide.

7. The composition of claim 6 wherein the block A of the block copolymer comprises repeating units deriving from N-vinyl pyrrolidone and the block B of the block copolymer comprises repeating units deriving from 2-ethyl-hexyl acrylate.

8. An emulsion comprising a composition C according to claim 1.

9. The emulsion of claim 8, wherein it is an inverse emulsion containing PAM homo- or co-polymers in their dispersed aqueous phase.

10. The emulsion of claim 8, wherein the content of composition C is between 0.5% and 5%, in mass, based on the total mass of the emulsion containing the composition C.

11. The emulsion of claim 8, comprising from 1% to 2% of the alkanolamide emulsifier; and from 0.001% to 0.5% of the copolymer, in mass, based on the total mass of the emulsion containing the composition C.

12. A method, comprising stabilizing an emulsion using the composition C of claim 1.

13. The composition of claim 1, wherein block A is distinct from a block having a lower critical solubility temperature (LCST).

14. The composition of claim 1, wherein block B is derived from mono-alpha-ethylenically-unsaturated monomers.

15. The composition of claim 2, wherein the ratio copolymer/alkanolamide corresponding to the quotient of the total mass of copolymer contained in composition C, to the total mass of the alkanolamide emulsifier contained in composition C is between 2 and 20%.

16. The emulsion of claim 10, wherein the content of composition C is between 1% and 4% in mass, based on the total mass of the emulsion containing the composition C.

17. The method of claim 12, wherein the emulsion is an inverse emulsion.

18. The method of claim 17, wherein the inverse emulsion contains a PAM homo- or co-polymer in its dispersed aqueous phase.

Description

EXAMPLES

[0184] Several emulsion have been prepared, comprising, in weight % based on the total weight of the emulsion: [0185] 70% of an aqueous solution of NaCl 2M [0186] 28% of an oil (Hydroseal G232H); and [0187] 2% of one of the composition C1 to C3 described in the table 1 below, herein referred as “emulsifier compositions” and comprising an alkanolamide emulsifier and a copolymer (the amounts being the weight of active matter based on the total weight of the emulsion)

[0188] The emulsions differ from each other only by the nature of the emulsifier composition (C1 to C3 respectively). All the emulsions have been prepared in the same following conditions: [0189] in each case, the considered emulsifier composition has first been mixed with the oil at 25° C.; [0190] then, the aqueous solution of NaCl has been added to the resulting mixture; [0191] an emulsification has been performed by stirring under Ultra Turrax at 13 500 rpm during 5 minutes after the addition of the aqueous solution of NaCl.

TABLE-US-00001 TABLE 1 the tested emulsifier compositions Composition emulsifier copolymer C1 1.7% Mackamide WS 1 Rhodibloc RS C2 1.7% Mackamide MO Rhodibloc RS C3 1.7% Mackamide WS 1 Dibloc copolymer 2EHA-DMA* *DMA = N,N-Dimethylacrylamide

[0192] Each emulsion has been observed after the emulsification (at time t=0). No coalescence or flocs have been observed.

[0193] Besides, the evolution of the mean diameter D50 of the droplets of the emulsion and of the oil split ratio have been observed over storage at 25° C. The obtained the results are reported in tables 2 and 3 below.

TABLE-US-00002 TABLE 2 Evolution of D50 Composition used in the emulsion Storage time C1 C2 C3 0 0.4 μm 0.3 μm 0.5 μm 1 month 0.3 μm 0.4 μm 0.3 μm 2 months 0.4 μm 0.4 μm 3 months 0.4 μm 0.4 μm 4 months 0.4 μm 0.3 μm 5 months 0.3 μm 0.3 μm 6 months 0.4 μm 0.4 μm 0.3 μm

TABLE-US-00003 TABLE 3 evolution of the oil split ratio Composition used in the emulsion Storage time C1 C2 C3 0 0 0 0 1 month 1 mm 0.5 mm   0 2 months 2 mm 2 mm 1 mm 3 months 2 mm 2 mm 1 mm 4 months 2 mm 2 mm 1.5 mm   5 months 2 mm 2 mm 2 mm 6 months 2.5 mm   3 mm 2 mm