Oil in Water Wax Emulsion Composition

Abstract

The present invention relates to compositions in the form of an oil-in-water emulsion preferably comprising an aqueous phase, a natural wax, at least two surfactants, and a neutralizing agent.

Claims

1. An oil-in-water emulsion composition comprising a solids portion, the solids portion comprising a wax, an aqueous phase, an emulsifying package, and a neutralizing agent.

2. (canceled)

3. The composition of claim 1 wherein the wax is a naturally derived, renewable resource, and has a melting point between 49-100° C. and a saponification value of above 20 mg KOH/g.

4. (canceled)

5. The composition of claim 3 wherein the wax is Oryza Sativa Bran Wax (rice bran wax).

6. The composition of claim 1 wherein the emulsifying package comprises at least two nonionic surfactants.

7-14. (canceled)

15. The composition of claim 1 wherein the wax has a melting point between 49° C. and 100° C.

16-18. (canceled)

19. The composition of claim 6 wherein one of the at least two surfactants is an alcohol ether of ethylene oxide propylene oxide surfactant which contains saturated C8-C10 carbon chains with moles of ethoxylated and propoxylated chains.

20-23. (canceled)

24. The composition of claim 1 wherein the wax comprises free fatty acids and alcohols and the neutralizing agent is any agent to neutralize the free fatty acids and alcohols.

25. The composition of claim 24 wherein the neutralizing agent comprises a base which includes potassium hydroxide, sodium hydroxide, and/or amines such as ammonia, ethyl amines, ethanolamine, isopropylamines, and other amine derivatives in a weight amount

26-28. (canceled)

29. A method of preparing an oil-in-water emulsion composition, the composition comprising a solids portion, the solids portion comprising a wax, an aqueous phase, an emulsifying package, and a neutralizing agent, the method comprising the following steps: (a) mixing the solids, aqueous phase, emulsifier package, and neutralizing agent; (b) heating the mixture of step (a) to above a melting point of wax of step (c); (c) blending the heated mixture of step (b) with a wax, pre-emulsion, to form a new mixture; (d) maintaining the temperature of the mixture of step (c) until the mixture is fully blended and is dispersed as a blended aqueous mixture.

30. The method of claim 29, further comprising a step after step (d) of: (e) homogenizing the blended aqueous mixture of step (d).

31. (canceled)

32. The method of claim 29 wherein the wax is a natural wax.

33-36. (canceled)

37. The method of claim 29 wherein the emulsifying package comprises an alcohol ether, polyethylene glycol (PEG), and a secondary alcohol ethoxylate.

38. The method of claim 37 wherein the alcohol ether is an alcohol ether of ethylene oxide propylene oxide surfactant.

39. (canceled)

40. The method of claim 29 wherein the aqueous phase is a continuous aqueous phase that is opaque.

41. The method of claim 40 wherein the solids comprise 30%-65% by weight of the oil-in-water emulsion.

42-43. (canceled)

44. The method of claim 30 wherein the wax is a natural wax that is a long chain ester with phospholipids and free fatty acids and alcohols.

45-48. (canceled)

49. The method of claim 37 wherein the secondary alcohol ethoxylate contains a secondary chain whose length is approximately 30-60 moles of ethylene oxide.

50-51. (canceled)

52. The method of claim 29 wherein the wax comprises free fatty acids and alcohols and the neutralizing agent is any agent to neutralize the free fatty acids and alcohols.

53. The method of claim 52 wherein the neutralizing agent is comprised of ammonium hydroxide in a weight amount of 0.1-10% of the oil-in-water emulsion.

54-56. (canceled)

57. The method of claim 29 wherein in step (b) the mixture is heated to 5° C-10° C. (9° F.-18° F.) above the melting temperature of the wax of step (c).

58-59. (canceled)

60. The composition of claim 7 wherein the secondary alcohol ethoxylate contains a secondary chain whose length is approximately 41 moles of ethylene oxide.

61. (canceled)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0070] Wax emulsions have been used in many different applications and are preferred in formulating in certain applications due to the aqueous phase and ease of formulation. This invention addresses the issue of creating a high solids oil-in-water emulsion that would be phase stable while still retaining desirable physical attributes and maintaining regulatory compliance. Desirable physical attributes may include water resistance, a viscosity in the range of 1-10,000 centipoise (cps), sebum resistance, pH range of 7-10, smooth coating, and shear stability. Additionally, the present invention can meet compliance requirements in several countries for indirect and direct food contact, board coating applications, and personal care regulations, which may include Code of Federal Regulations (CFR) compliances for the United States, Guo Bio (GB) compliances in China, REACH regulations in the European Union, and other regulatory regulations which are known to those with skill in the art.

[0071] A preferred composition can be found in the below Table:

TABLE-US-00001 Component Alternatives Range Preferred Rice Bran Wax Naturally derived 40%-50%    45% (RBX) wax Polyethylene glycol  0%-3%     3% (PEG) Pareth-40 secondary alcohol 0%-5%     3% Alcohol ether of Ethoxylated 0.5%-1.5%     1% ethylene oxide propoxylated propylene oxide surfactant surfactant Ammonium Neutralizing Agent 0.5%-1%    0.81% Hydroxide Water None   59%-39.5% 47.19%
This emulsion is preferably formulated by blending the water and emulsifier package and then heating the solution to 190° F. (88° C.). Then ammonium hydroxide is added while the formulation is heated in a hood. Once the formulation is at approximately 190° F. (88° C.) the rice bran wax is added. The formulation is preferably mixed for approximately an hour between 190° F.-200° F. (88° C-94° C.) to allow the rice bran wax to melt and to emulsify. After the formulation has been fully blended and is in a homogenous phase for an hour, the formulation is then homogenized at 2000 psi (13.8 Mpa) in a homogenizer. After homogenization, the emulsion is cooled to room is temperature and filtered through a 300-micron filter.

[0072] The emulsifier package preferably comprises PEG and Ethoxylated or alcohol surfactant. In a preferred embodiment, the alcohol surfactant is a Pareth surfactant in which the Pareth-40 is preferred. In a more preferred embodiment, the emulsifier package further comprises the ethoxylated propoxylated surfactant. Other known emulsifier packages that are suitable for use with higher wax solids could be used, such as one comprising a fatty alcohol, linear surfactant and polysaccharide; however, the emulsifier package of the present invention displays increased stability of the higher wax emulsion.

[0073] In some preferred embodiments, the secondary surfactant of the alcohol ether of ethylene oxide is not needed. In some preferred embodiments, a primary alcohol may be used instead of the secondary alcohol.

[0074] Polyethylene Glycol is preferably 300 Daltons in molecular weight in the final formulation.

[0075] The present invention is able to achieve a higher solids oil-in-water emulsion that is stable at both room temperature and elevated temperatures (such as around 40-60° C., preferably around 50° C.), pH of 7-10.5 (preferably, pH is 8-10), viscosity range of 1-10,000 cps (preferably, it is around 200-5000 cps, preferably with solids influencing the viscosity), good hand shear, contact angle with water being over 90° with no staining, and sebum contact angle over 90° with no staining

[0076] A preferred composition formulation comprises:

[0077] a natural wax, polyethylene glycol (PEG), alcohol, at least one surfactant, and a neutralizing agent.

[0078] Preferably, the natural wax is rice bran wax (RBX). However, other natural, petroleum, and synthetic waxes such as white beeswax, yellow beeswax, cetyl palmitate, carnauba wax, beeswax, lanolin wax, Chinese insect waxes, rice wax, candelilla wax, ouricury wax, esparto wax, cork fibre wax, sugarcane wax, Japan wax, sumac wax, montan wax, microcrystalline waxes, paraffin waxes and ozokerite, polyethylene waxes, and waxes obtained by the Fischer-Tropsch process could also be used. Preferably, the composition of the present invention is 20-60% natural wax; more preferably, it is 40-55% natural wax; most preferably it is 40-55% rice bran wax.

[0079] Preferably, the PEG has a molecular average weight up to 10,000 Daltons. More preferably, the PEG has a molecular average weight of 50-10,000 Daltons. Most preferably, the PEG has a molecular average weight of 300 Daltons. Preferably, the composition of the present invention is 0.1-10% PEG. More preferably, it is 3% PEG.

[0080] Preferably, the composition of the present invention is 0.1-10% alcohol. More preferably, it is 1% alcohol.

[0081] Preferably, the composition of the present invention comprises at least one surfactant. Preferably the composition of the present invention comprises 0.1-10% surfactant, more preferably 3% surfactant. More preferably, the composition of the present invention comprises at least two surfactants. Preferably, these two surfactants are C12-C14 Pareth-40 surfactant and C8-C10, ethoxylated propoxylated surfactant.

[0082] Preferably, the present invention contains 0.1-10% neutralizing agent. More preferably, the present invention contains 0.25-1.0% neutralizing agent. Preferably, the neutralizing agent is an alkaline agent. More preferably, it is ammonium hydroxide.

[0083] Preferably, the rest of the composition is water.

[0084] In some preferred embodiments, the water and emulsifier package (PEG and both surfactants) is blended and then the solution is preferably heated to 180° F.-210° F. (82° C.-99° C.). More preferably, the solution is heated to 190° F. (88C). Then, the neutralizing or alkaline agent is preferably added while the formulation is heated, preferably in a hood. Preferably, once the formulation reaches the desired temperature, the natural wax is added. The formulation is preferably mixed for 30 minutes to 120 minutes between 190° F.-210° F. (82° C-99° C.) to allow the natural wax to melt and to emulsify.

[0085] In some preferred embodiments, after the formulation has been fully blended and is in a homogenous phase, the formulation is then preferably homogenized, preferably at 1000-3000 psi (6.9-20.7 Mpa), more preferably at 2000 psi (13.8 Mpa) in a homogenizer. This additional step is not necessary for the composition stability, but it provides a more consistent range of particle size. After homogenization, the emulsion is preferably cooled to room temperature and filtered, preferably through a 100-300-micron filter. The product has been tested for stability for one year at ambient temperature and 50° C. without changing characteristics. We anticipate that continued tests at these temperatures will show continued stability.

[0086] All measurements disclosed herein are at standard temperature and pressure, at sea level on Earth, unless indicated otherwise. All materials used or intended to be used in a human being are biocompatible, unless indicated otherwise.

[0087] The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.