EP-4741032-A1 - PERFORMANCE ENHANCEMENT OF DEFOAMER FORMULATIONS VIA A MATRIX ENCAPSULATION STRATEGY

Abstract

An encapsulated defoamer composition is described which provides for sustained defoamer performance.

Inventors

• MOTL, Nathan
• Urbath, Jonas
• SCHIERLE, Thorsten

Assignees

• Evonik Operations GmbH

Dates

Publication Date

20260513

Application Date

20241107

Claims (20)

1. A defoamer composition, comprising: discrete composite particles comprising an active defoamer dispersed in a gel matrix of an insoluble encapsulant material.
2. A defoamer composition for a foam generating system, the composition comprising: (i) composite particles comprising a gel matrix of an insoluble encapsulant material and an active defoamer dispersed therein; and (ii) water.
3. A defoamer composition according to any preceding claim, wherein the insoluble encapsulant material is a polysaccharide and/or a polysaccharide hydrogel and/or an acidic polysaccharide.
4. A defoamer composition according to any preceding claim, wherein the insoluble encapsulant material is a divalent cationic alginate salt.
5. A defoamer composition according to claim 4, wherein a divalent cation is at least one selected from the group consisting of calcium, magnesium, and iron.
6. A defoamer composition according to any preceding claim, wherein the active defoamer further comprises at least one selected from the group consisting of an anticaking agent, a dehydrating agent, and a moisture absorbing agent; optionally wherein the insoluble encapsulant material further comprises calcium silicate.
7. A defoamer composition according to any preceding claim, wherein under chemical, physical and/or mechanical force, the active defoamer is gradually released from the gel matrix.
8. A defoamer composition according to claim 7, wherein the mechanical force is from at least one selected from the group consisting of gear pump recirculation, impeller blades in a CSTR, planetary mixers and overhead mixers.
9. A defoamer composition according to any preceding claim, wherein the active defoamer is at a concentration range of about 1 % to about 90 % by weight, preferably about 1-about 50 wt. %, about 1-about 40 wt.%, about 1-about 30 wt. %, and/or preferably about 2-about 20 wt. %, of the composite particles.
10. A defoamer composition according to any preceding claim, wherein the discrete composite particles comprise a particle size of from about 1 mm to about 500 mm preferably about 1 mm to about 250 mm, about 1 mm to about 100 mm, about 1 mm to about 50 mm, and/or about 1 mm to about 10 mm.
11. A defoamer composition according to any preceding claim, wherein gel droplets comprising the insoluble encapsulant material and the active defoamer comprise a droplet size of from about 1 mm to about 500 mm, preferably about 1 mm to about 250 mm, about 1 mm to about 100 mm, about 1 mm to about 50 mm, and/or about 1 mm to about 10 mm.
12. A process for encapsulating a defoaming system, the process comprising: (i) dispersing a defoaming system comprising an active defoamer into a monovalent polysaccharide salt solution to produce a mixture; (ii) adding the mixture dropwise to an aqueous divalent cationic salt solution for chelation and/or ion exchange; and/or (iii) forming a gel of an insoluble divalent cation polysaccharide matrix encapsulating the defoaming system.
13. A process according to claim 12, wherein the monovalent polysaccharide salt solution is at least one selected from the group consisting of an alginate solution, a uronic acid salt solution, a hyaluronic acid salt solution, a chondroitin sulfate salt solution, a pectin salt solution, a chitosan salt solution, and a polysaccharide hydrogel solution; and optionally further comprises a polyacrylamide, polystyrene, and/or polyvinyl chloride.
14. A process according to any one of claims 12 or 13, wherein the divalent cation is at least one selected from the group consisting of a calcium, a magnesium, and an iron cation.
15. A process according to any one of claims 12-14, wherein the aqueous divalent cationic salt solution is an aqueous calcium chloride solution.
16. A process according to any one of claims 12-15, further comprising adding calcium silicate to the active defoamer prior to dispersing.
17. A process according to any one of claims 12-16, wherein the defoaming system comprises at least one selected from the group consisting of hydrophobic particles, an aqueous dispersion, an emulsion, and an oleophilic substance.
18. A process according to any one of claims 12-17, wherein the gel produced comprising the active defoamer is homogeneous.
19. A process according to any one of claims 12-18, wherein the process does not comprise a film coating or a core-shell encapsulation of the active defoamer.
20. An encapsulated defoamer obtained by the process according to any one of claims 12-19.

Description

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present disclosure relates generally to defoamers and antifoams, as well as a method of enhancing the performance of the same using a matrix encapsulation strategy. DESCRIPTION OF RELATED ART Defoamers and antifoams have seen great utility in a cornucopia of manufacturing process. Their ability to disrupt and prevent the formation of foam in a variety of systems has proved invaluable for increasing process efficiency, waste reduction and ease of use. Application areas of these materials are diverse and include industries such as coatings, textiles, food processing, fermentation, paper manufacturing, and medical applications. Foams are formed when pockets of gas are trapped within a liquid or solid media in the presence of surfactants. Surfactants will often nucleate around these gas pockets, resulting in an increase in bubble stability and consequent foam formation. The surfactants typically form a double layer, effectively trapping a thin liquid film or lamella between two gas phase layers. These lamellae provide stability for the entrapped gasses as the foam structure continues to grow. The specific thickness and strength of the foam lamellae, as well as size of the individual gas bubbles within the foam, will vary depending on the specific liquids and surfactants present in the foaming system. Although most foam generating systems tend to be largely aqueous, non-aqueous systems are possible. Defoamer performance is typically quantified by examining foam "knock-down" and foam "hold-down". "Knock-down" is typically measured by the rate and magnitude of the initial foam decrease after the introduction of the defoamer into the foaming system. Superior performance is characterized by a relatively rapid decrease in foam, and a relatively low level of remaining foam after the initial antifoam action has subsided. Conversely, defoamer "hold-down" is used to quantify how long a given defoamer or antifoam will keep the foam to a minimum before it is rendered inactive and foam growth resumes. Due to the complex nature of the systems in which defoamers are often employed (fermentation reactors, food processing, industrial coatings, etc.). The defoamer may often be incompatible with the system and introduce defects, instability, or other undesirable traits into the process. Such incompatibilities are oftentimes more pronounced at increased defoamer concentrations. All currently available defoamers are subject to eventual defoamer deactivation in some form. Eventually the defoamer or antifoam will lose efficacy as it is exposed to continuous foam generation. Defoamer formulations are engineered to minimize deactivation and prolong foam "hold-down" for as long as possible. Developing a general strategy to prevent deactivation of defoamers has proven difficult due to the diversity of defoamer formulations. For defoamer formulations that contain hydrophobic particles, it is thought that deactivation is the result of migration of the particulate matter out of the formulation droplets and the subsequent formulation of aggregates. For defoamers that are comprised of oils in the absence of particulates, deactivation is due to the breakdown of defoamer droplets below the size necessary to effectively rupture foam lamellae. Additionally, hydrophobic particles may further promote antifoam activity in some systems by absorbing surfactants onto their surface. As a result of the inherent system specificity, solutions to effectively inhibit defoamer deactivation are often non-transferable from one foam generating system to another. For example, U.S. 9,579,291 describes the controlled-release of a defoamer from a porous carrier that encapsulated by an aqueous alginate layer. Although robust, using a core-shell encapsulated porous carrier instead of insoluble gel matrix, does not necessarily provide the best release profile for defoamer applications. Additionally, soluble alginate encapsulation would degrade too quickly to be effective in more demanding foam systems. Similarly, U.S. 4,400,391 describes the use of alginate beads for the controlled-release of bioactive materials, specifically pesticides. The potential controlled-release of the bioactive from the encapsulate may occur through leaching, diffusion, dissolution, and degradation. U.S. 5,024,937 describes the use of an oil-based antifoam droplets that are encased within solid particles of a water soluble encapsulant. The resulting material was then introduced into fermentation broths where exposure to the aqueous environment triggered the immediate release of the oil-based antifoam. U.S. 5,773,407 describes the preparation of an encapsulated antifoam by use of an alkylalkoxysilane condensation reaction product four laundry detergent applications. The encapsulation was accomplished by the polycondensation of the alkylalkoxysilane, forming a protective shell around the defoamer emulsion. This shell is then mechanically deg