US Patent 5866041a.docx

1、US Patent 5866041aUS Patent 5866041 - Fatty acid defoamers with improved shelf lifeUS Patent Issued on February 2, 1999Estimated Patent Expiration Date: June 26, 2017Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adju

2、stments, failure to pay maintenance fees, or other factors which might affect the term of a patent.AbstractClaimsDescriptionFull TextView Patent Images (PDF)(Registered users only)AbstractThe present invention provides an antifoam emulsion with improved shelf-life and a method for making same. The i

3、mproved shelf-life results from dispersing a fatty alcohol dispersion in an emulsion of another liquid. To this end, the antifoam emulsion of the present invention includes an internal phase of a fatty alcohol dispersion, an emulsifier, and an external phase including a water insoluble or partially

4、miscible liquid. ClaimsWe claim:1. An antifoam mixed emulsion comprising:an internal oil-in-water phase including a fatty alcohol, a first emulsifier, and water;a second emulsifier; andan external oil phase including a carrier liquid;wherein said first emulsifier disperses said fatty alcohol in the

5、internal oil-in-water phase and said second emulsifier disperses said internal oil-in-water phase in said external oil phase.2. The antifoam emulsion of claim 1 wherein the fatty alcohol is a fatty alcohol obtained from a Ziegler process.3. The antifoam emulsion of claim 1 wherein the fatty alcohol

6、is a fatty alcohol obtained from an oxo synthesis.4. The antifoam emulsion of claim 1 wherein the second emulsifier is selected from the group consisting of: alkyl phenol ethoxylate; alcohol ethyoxylate; polyether-polysiloxane; sorbitan fatty acid ester; poly-12-hydroxy stearic acid polyethylene gly

7、col esters; polyglycerol fatty acid esters and poly-12-hydroxy stearic acid sorbitol esters. 5. The antifoam emulsion of claim 1 wherein the carrier liquid is selected from the group consisting of: guerbet branched alcohol; octanol; decanol; oleyl alcohol; mineral oil; light petroleum distillates; p

8、olybutenes; silicone oil; polypropylene glycol; and mixtures thereof.6. The antifoam emulsion of claim 5 wherein the guerbet branched alcohol is selected from the group consisting of: 2-hexyl-decanol; 2-octyl-dodecanol; 2-butyl-octanol; 2-decyl-tetradecanol and mixtures thereof.7. The antifoam emuls

9、ion of claim 1 wherein the external oil phase further includes hydrophobic particles.8. The antifoam emulsion of claim 7 wherein the hydrophobic particles are present in a range of approximately 0.1% to 10% by weight of the antifoam composition.9. The antifoam emulsion of claim 1 wherein the carrier

10、 liquid is a water insoluble liquid and is present in a range of approximately 20% to 80% by weight of the antifoam composition.10. The antifoam emulsion of claim 1 wherein the second emulsifier is present in a range of approximately 0.10% to 10% by weight of the antifoam composition.11. The antifoa

11、m emulsion of claim 1 wherein the internal oil-in-water phase is present in a range of approximately 10% to 70% by weight of the antifoam composition.12. A method for improving the shelf-life of a fatty alcohol defoamer comprising the steps of:providing a fatty alcohol dispersion comprising: a fatty

12、 alcohol; a first emulsifier; and water; anddissolving a second emulsifier in a water insoluble liquid to form a mixture; andmixing the fatty alcohol dispersion with the mixture thereby forming a mixed emulsion of the fatty alcohol dispersion with a water insoluble liquid, wherein the fatty alcohol

13、dispersion is a dispersed phase inside the mixed emulsion and the water insoluble liquid is an external oil phase of the mixed emulsion;wherein said first emulsifier disperses said fatty alcohol in said fatty alcohol dispersion and said second emulsifier disperses said fatty alcohol dispersion in sa

14、id external oil phase.13. The method of claim 12 wherein the step of providing the fatty alcohol dispersion is further defined by providing approximately 10% to 70% by weight of the fatty alcohol dispersion based on the mixed emulsion.14. The method of claim 12 further comprising the step of adding

15、hydrophobic particles to the external oil phase of the emulsion.15. The method of claim 13 wherein the hydrophobic particles are hydrophobic silica.16. The method of claim 12 wherein the water insoluble liquid is present in a range of approximately 20% to 80% by weight of the antifoam composition.17

16、. The method of claim 12 further comprising the step of homogenizing the mixed emulsion with a high-shear device.18. The method of claim 12 wherein the second emulsifier is a mixture of two or more emulsifiers. DescriptionBACKGROUND OF THE INVENTIONThe present invention generally relates to antifoam

17、s for use in the paper industry. More specifically, the present invention relates to fatty alcohol antifoams with improved shelf life.Foam is a material made up of gas bubbles separated from one another by films of liquid. Although foams of exceptional stability are desired in some commercial applic

18、ations, foam is a nuisance in many situations. For instance, in the glue and paper industries, foams cause undesirable complications. A common recourse is the addition of chemical antifoams, which are sometimes insoluble liquids of very low surface tension. When a droplet of such a liquid is sprayed

19、 onto the foam or is carried into it by mechanical agitation, it spreads spontaneously and rapidly at the surface of the film, virtually sweeping the foam away as it does so. Liquids frequently used for this purpose are octyl alcohol, tributyl phosphate, silicone and many patented preparations.Antif

20、oams, such as fatty alcohol defoamers, thus serve a critical function in a variety of industries, such as the paper industry. However, a disadvantage of commercial antifoam formulations is their limited shelf-life. Known antifoams often cream during storage and in some cases thicken to such an exten

21、t that they can no longer be pumped. This thickening or gelation renders the application of the fatty alcohol active ingredient to a foaming system difficult at best, limiting the sale of products containing substantially the fatty alcohol active ingredient.Moreover, another disadvantage of known an

22、tifoams is that they are ineffective at elevated temperatures. Antifoam emulsions, which are conventionally used in papermaking, are known to become less effective if the temperature of the aqueous system to be defoamed increases above 50 C. At temperatures above 60 C., an even more rapid decrease i

23、n the effectiveness of the antifoam occurs when known oil-in-water emulsions are used. Since an increasing tendency for water circulations in the paper mills is to be closed ones, the result is that the temperature of the water conveyed in the circulation increases during papermaking, so that the ef

24、fectiveness of the antifoams used to date decreases substantially.Therefore, a need exists for a fatty alcohol antifoam formulation with improved shelf life and improved elevated temperature performance.SUMMARY OF THE INVENTIONThe present invention provides a fatty alcohol defoamer with increased sh

25、elf-life as well as improved performance under elevated temperature conditions. The improved shelf-life of the present invention results from providing the active ingredient of an antifoam formulation, namely a water-based dispersion of the substantially fatty alcohol ingredient, in a form that is i

26、nsensitive to increases in viscosity or age. In this regard, the present invention provides forming a mixed emulsion wherein the fatty alcohol water-based dispersion is contained as the internal or dispersed phase of another fluid. Whereas, the improved elevated temperature performance results from

27、the addition of hydrophobic particles to the external or continuous phase of the emulsion.The present invention provides an antifoam emulsion that exhibits increased stability over a longer storage period and under a variety of conditions. The antifoam emulsion includes an internal phase consisting

28、of a fatty alcohol dispersion. The emulsion also includes an emulsifier and an external phase including a water insoluble or partially miscible liquid.Conventional fatty alcohol dispersions can be used for the internal phase of the present invention. For example, fatty alcohols obtained from the Zei

29、gler process or the oxo process are suitable. Additionally, naturally occurring materials are also acceptable.Suitable carrier liquids for the external phase again are any water insoluble or partially miscible liquid. Examples of the carrier liquid include: Guerbet branched alcohols; octanol; decano

30、l; oleyl alcohol; mineral oil; light petroleum distillates; polybutenes; silicone oil and mixtures thereof.To promote the formation and stabilization of the mixed emulsion, an emulsifier is used. Simple monomeric emulsifiers as well as polymeric emulsifiers can be used in the present invention. Exam

31、ples of suitable emulsifiers that can be used to form the antifoam emulsion are alkyl phenol ethoxylates, alcohol ethoxylates, polyether-polysiloxanes, and sorbitan fatty acid esters.In a preferred embodiment, the mixed emulsion also includes hydrophobic particles. Use of hydrophobic particles, such

32、 as hydrophobic silica, in the external phase not only imparts a degree of mechanical stability to the emulsion, but also improves the elevated temperature defoaming performance of the emulsion.The present invention also provides a method for improving the shelf-life of a fatty alcohol defoamer. This method includes an initial step of providing a fatty alcohol dispersion. Then, the fatty alcohol dispersion is formed into a mixed emulsion within a carrier liquid. In such emulsion, the fatty