Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2001-09-14
2002-11-05
Lovering, Richard D. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C516S030000, C516S076000, C516S920000, C516S925000, C523S336000, C524S804000, C526S932000
Reexamination Certificate
active
06476168
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to water-in-oil emulsions having alkoxylates of 6,6-dimethylbicyclo[3.1.1]hept-2-ene-2-ethanol as activating agents. Further, the present invention relates to methods of using such emulsions.
2. Description of the Prior Art
Water-soluble polymers, both synthetic and natural, have been employed in aqueous solution as thickening and flocculating agents. They have found commercial use in a variety of end uses such as wastewater treatment and water purification, papermaking, petroleum recovery and oil drilling mud stabilizers.
Water-soluble polymers are typically stored and delivered in the form of water-in-oil emulsions. The emulsion form is preferred because of the tendency of the polymers to agglomerate and clump in aqueous solution. Use of the emulsion form enhances dispersion of the polymers in aqueous media and environments in the various end uses.
When water-in-oil emulsions containing water-soluble polymers are introduced into an aqueous medium, a dispersion of oil droplets containing the polymers is formed. For the polymers to modify the physical characteristics and properties of the medium, the polymers must be released from the internal aqueous phase within the droplets to the external aqueous phase of the medium. This release phase is frequently referred to as “inversion.”
Although the phenomena of inversion is not well understood, it is believed to occur as a result of osmotic pressure. The osmotic pressure may occur as a result of gradients in chemical potential between the internal aqueous phase and the external aqueous phase. Water permeates into the oil droplets, causing the internal aqueous phase and, concomitantly, the oil droplet itself, to swell or expand. When the oil droplets are no longer able to contain the swollen internal aqueous phase, it along with the water-soluble polymer, is released into the external aqueous phase.
Due to the relatively high cost of the water-soluble polymers, it is desirable to maximize their effect as thickeners and flocculants and minimize required levels. One means of accomplishing this is to enhance the efficiency of the inversion process. The efficiency of the inversion process can be enhanced by the inclusion of surfactants, frequently referred to as “activating agents” in this context. The prior art discloses the use of various surfactants or activating agents in inversion processes in U.S. Pat. Nos. 3,624,019; 3,734,873; 3,997,492; 4,024,097; 4,147,681; and 4,252,706. Some surfactants disclosed include ethoxylated alkyl phenols, polyoxyethylene vegetable oil, polyoxyethylene fatty alcohols, sulfated castor oil, nonyl phenol ethoxylates, sorbitan monooleate, fatty amides and fatty alkanolamides.
Although known activating agents have been effective in accelerating inversion processes, it would be desirable to have an activating agent that provided better acceleration and release of water-soluble polymers in aqueous medium.
Some of the known activating agents, particularly the ethoxylated alkyl phenols most commonly used, have raised environmental concern due to slow biodegradation potential. It would further be desirable to have an activating agent that exhibited minimal environmental impact.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an improved activating agent for use in a water-in-oil emulsion in an inversion process.
Another object of the present invention is to provide an activating agent that provides a fast inversion time for a water-in-oil emulsion having a water-soluble polymer therein.
Another object of the present invention is to provide an activating agent that has a relatively low impact on the environment.
This and other objects of the invention are seen in a water-in-oil emulsion useful in an inversion process. The emulsion has an aqueous phase having a water-soluble polymer and an activating agent of the following formula:
wherein n=0 to 10 and m=2 to 25. The moiety qualified by the integer “n” corresponds to oxypropylene units. The moiety qualified by the integer “m” corresponds to oxyethylene units. The oxypropylene and oxyethylene units may be of block distribution or intermixed in random or tapered distribution along the chain.
There is an inversion process according to the following: a) providing an water-in-oil emulsion having a water-soluble polymer in the aqueous phase and the activating agent; b) introducing the emulsion into an aqueous medium and c) allowing sufficient time for the emulsion to invert.
There is another inversion process according to the following: a) providing an water-in-oil emulsion having a water-soluble polymer in the aqueous phase; b) introducing the emulsion into an aqueous medium having the activating agent and c) allowing sufficient time for the emulsion to invert.
DETAIL DESCRIPTION OF THE INVENTION
It was found surprising and unexpected that a water-in-oil emulsion having a water soluble polymer could be formulated to deliver a fast activation time (inversion time) in aqueous media. The activation agent comprises an alkoxylate of 6,6-dimethylbicyclo[3.1.1]hept-2-ene-2-ethanol. The term “activating agent” and the term “surfactant” may be used interchangeably herein.
The activating agent useful in the process of the present invention is of the following formula:
wherein n=0 to 10 and m=2 to 25. Preferably, n=0 to 5 and m=4 to 15. Most preferably, n=2 to 4 and m=4 to 13. The moiety qualified by the integer “n” corresponds to oxypropylene units. The moiety qualified by the integer “m” corresponds to oxyethylene units. The oxypropylene and oxyethylene units may be of block distribution or intermixed in random or tapered distribution along the chain. The compounds of the formula may also be described as alkoxylates of 6,6-dimethylbicyclo[3.1.1]hept-2-ene-2-ethanol.
Emulsions of the present invention will exhibit an activation time (inversion time) in water of preferably about 30 second or less, more preferably about 20 seconds or less and most preferably about 10 seconds or less. Activation time is determined in accordance with the standard vortex method described below.
The water-soluble polymer is obtained by chain polymerization of monomers selected from the group consisting of acrylamide, methacrylamide, acrylic acid and the salts thereof, methacrylic acid and the salts thereof, acrylamidomethylpropane sulfonic acid and the salts thereof, and other vinyl carboxylic or sulfonic acids and their salts, and amine monomers selected from the group consisting of methacrylamidopropyltrimethylamine, acrylamidopropyltrimethylamine, acryloyloxyhydroxypropyltrimethylamine, methacryloyloxyhydroxypropyltrimethylamine, acryloyloxyethyltrimethylamine, methacryloyloxyethyltrimethylamine and their salts, diallyldimethylammonium chloride or sulfate, methylenebisacrylamide, diacetone acrylamide, N-alkyl substituted acrylamides, ethylene glycol dimethacrylate, and alkoxylated (meth)acrylates. The foregoing list of monomers is exemplary, and is not to be construed as limiting. The structure and properties of the polymer may be controlled by monomer content and degree of polymerization. Preferably, the water-soluble polymer will be formed in-situ via emulsion polymerization. Useful polymers and processes for making polymers are disclosed in U.S. Pat. Nos. 3,284,393; 3,624,019; 3,734,873; 3,997,492; 4,024,097; 4,147,681; and 4,252,706, which are incorporated herein by reference.
Water-in-oil emulsions of the present invention are preferably formed as a product of emulsion polymerization. In emulsion polymerization, monomers of the desired water-soluble polymer are mixed with water and any water-soluble adjuvants to form an aqueous phase, which is subsequently blended with an oil phase to form a constituted water-in-oil emulsion. Polymerization is then effected. The activating agent, one or more alkoxylates of 6,6-dimethylbicyclo[3.1.1]hept-2-ene-2-ethanol, can be added to the constituted
Dahanayake Manilal S.
Joye Jean-Luc
Li Fang
Lovering Richard D.
Ohlandt Greeley Ruggiero & Perle L.L.P.
Rhodia Inc.
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