WO1991000763A1

WO1991000763A1 - Low viscosity defoaming/antifoaming formulations

Info

Publication number: WO1991000763A1
Application number: PCT/US1990/003886
Authority: WO
Inventors: Manilal S. Dahanayake
Original assignee: Rhone-Poulenc Surfactants And Specialties, L.P.
Priority date: 1989-07-12
Filing date: 1990-07-11
Publication date: 1991-01-24
Also published as: IL95029A0; AU6063590A

Abstract

The present invention relates to balanced hydrophobic/hydrophilic liquid formulations comprising: (a) between about 10 and about 90 % by weight of an alcohol alkoxylate having formula (I), (b) between about 90 and about 10 % by weight of polypropylene glycol having formula (II), and (c) between about 0.3 and about 10 % by weight hydrophobic silica based on (a) + (b). The invention also pertains to the use of the above mixture in foamed liquids or liquid susceptible to foaming.

Description

LOW VISCOSITY DEFOAMING/ANTIFOAMING FORMULATIONS

PRIOR ART

The polypropylene glycols and polyoxyethylene-polyoxypropylene copolymers which have been employed individually as antifoaming agents have several drawbacks. Primarily, they have limited water solubility and dispersibility so that large amounts of these antifoamers must be employed and, even then, the defoa ing action is relatively low. Generally, a foam head of less than 2 cm on a 60 square cm surface area is the upper limit of tolerance for commercial defoaming applications and for certain uses not more than 0.3 cm is required. Secondly, formulations containing these compounds are somewhat viscous which presents pumping difficulties in antifoaming processing. Several solid non-foaming dispersing formulations have also been proposed as in U.S. 3,959,176; however these present problems of dispersibility and cannot be pumped into foamable solutions.

Accordingly, it is an object of this invention to overcome the above deficiencies of the prior art and to provide a particularly effective antifoaming/defoaming mixture which is economically prepared.

Another object of this invention is to provide a liquid mixture which is capable of defoaming an aqueous system at a greatly increased rate.

Another object is to provide a liquid antifoaming/defoaming composition having significantly reduced viscosity which can be most economically incorporated into a foamable liquid or added to a foam.

Still another object is to prepare a composition which, in addition to its antifoaming and defoaming properties, provides antiswelling in solutions of various polymers. These and other objects of the invention will become apparent from the following description and disclosure.

THE INVENTION

In accordance with this invention there is provided a liquid antifoaming/defoaming mixture or blend of components having a cloud point less than 35 and comprising:

(a) between about 10 and about 90% by weight of an alcohol alkoxylate having the formula

CH., R-0-(CH₂CHO)_χ(CH₂CH₂0)yH ;

(b) between about 90 and about 10% by weight of polypropylene glycol having the formula

CH-, I ^J HO(CH₂-CHO)_zH

and

(c) between about 0.1 and about 10% by weight hydrophobic silica based on (a) + (b) ,

wherein R is linear or branched chain alkyl having from 4 to 22 carbon atoms or a mixture thereof and is hydrophobic in character; x has a value of from 2 to 20; y has a value of from 0 to 15 and z has a value of from 10 to 200; with the proviso that when the number of carbon atoms in R, is less than 11, the value of x exceeds the value of y. It is to be understood that the values of x and y represent the total number of units in component (a) and do not define the order in which they appear; accordingly the formula of component (a) can also be written as

CH, RO(CH₂CH₂0)_y(CH₂CHO)_χH

where the ethoxylated and propoxylated units occur randomly or alternately in the compound.

The cloud point of instant mixtures can vary, from about 1 to about 35, although a cloud point of from about 1 to 25 in distilled water is preferred.

Preferred blends of the present composition are those wherein component (a) and component (b) are each present in an amount between about 35% and about 65% by weight; most preferred are those having about equal proportions of component (a) and component (b) and wherein R is C₈ to C₂₂ alkyl and mixtures of said alcohol alkoxylates. In the compositions of this invention, the moles propylene oxide units, with respect to ethylene oxide units is at least 50%.

The hydrophobic silica is preferably employed at concentrations between about 0.5 and about 8% by weight, most desirably, when a liquid mixture having a viscosity of not more than 500 centipoises (cps) is required, the concentration of the silica is not greater than 5% by weight. Although the viscosity of the liquid mixture can vary between about 100 and about 3,000 cps, depending upon its intended use, lower viscosities of less than 550 are usually desired for processing purposes. While increased hydrophobic silica content materially raises the viscosity, such increased amounts do not provide any antifoaming benefit. Accordingly, the amount of hydrophobic silica above 10% by weight is not desirable. The hydrophobic silica component of the composition, as known in the art, is prepared from hydrophilic silica which is treated to render the silica hydrophobic. One suitable method for rendering the silica hydrophobic is to permanently affix a liquid hydrophobic polysiloxane oil onto the silica particles. Hydrophobic silica is well known in the art and, accordingly, no detailed description thereof is deemed necessary for a complete understanding of the present invention. The preparation and use of hydrophobic silica is described in U.S. Patent Nos. 3,207,698; 3,408,306; and 3,076,768, as well as the refeences referred to in such patents, all of which are hereby incorporated by reference. A preferred silica is a precipitated silica, such as the precipitated silica sold as Quso-G30 or Quso WR-83.

The above blend of components provides a hydrophobic/hydrophilic balance which allows faster diffusion of the antifoamer composition into the liquid/air interface and rapidly transports silica to the interface where a small amount efficiently performs defoaming action. The components of the above mixture also interact to effect destructurization of the monomolecular foamed layer by increasing the free energy of interaction between the foam forming molecules which leads to liberation of air and collapse of bubbles. Because of the hydrophobic/hydrophilic balance in the above formulation, the present composition has greater affinity for and faster action in aqueous systems which are subject to foaming. The present blend is capable of reducing the foam head of a foamed liquid by at least 70% upon contact and in less than 1.5 minutes completely destroys the foam.

In addition to its antifoaming and defoaming functions, the present composition provides antiswelling properties to certain polymers such as polyvinyl halides, polypropylenes , polyethylenes, polytetrafluoroethylene, polychlorotrifluoroethylene and the like. Examples of foamed solutions to which the present composition is applied, include the alkali and alkaline earth metal salts, as well as ammonium salts, of alkyl benzene sulfonates and lauryl sulfates, lauryl ether sulfates, alkoxylated alkyl phenols, urethane polymers, phosphate ester surfactants, salts of fatty acids employed in the paper making industry and photopolymers such as methacrylic alkyl esters and their carboxylic salts employed for printed board circuits in the electronic industry. The present blends are useful as defoamers or antifoamers for laundry detergents, dishwashing formulations, paper making processes, metal working processes and many others.

To effect defoaming or antifoaming only a small amount of the blend is needed to provide the desired result. Generally between about 0.001% and about 3% by weight, preferably between about 0.05% and about 0.5% by weight of the present blend, based on foamed or foamable liquid, is employed to defoam on contact. The present mixture is economically and conveniently prepared by merely mixing components (a) , (b) and (c) in any order at a temperature between about 10°C. and about 100^βC. under atmospheric conditions for a period of up to 3 hours depending upon the volume and the mixing equipment employed. Generally, the formulation is prepared within a 1 hour mixing period at ambient temperature. The resulting mixture is preferably used in undiluted condition; although in certain cases where desired it can be diluted to a desired concentration with an inert solvent such as water, PEG, PPG, benzene, heptane, hydrocarbons and the like before contact with a foamed layer or before admixture wit a foamable liquid prior to agitation. The defoaming or antifoaming operations are carried out under the same conditions of temperature and pressure described above using conventional foam breaking or liquid mixing techniques. Having generally described the invention, reference is now had to the accompanying examples which include preferred embodiments of the invention. These examples are not to be construed as limiting to the scope of the present antifoaming/defoaming compositions which are more broadly set forth and in the appended claims.

EXAMPLE 1

The following composition A was mixed for 5 minutes at ambient temperature under atmospheric conditions in a 200 ml glass beaker.

(a) 50.0 g. of polyethoxylated (5 moles) - polypropoxylated (7 moles) heteric mixture of C₁₂ to C₁₄ linear alcohols

(b) 49.0 g. of polypropylene glycol (MW 4,000) (ALKAPOL 4000) and

(c) 1.0 g. of hydrophobic silica (QUSO WR-83)

The antifoaming property of the above composition was tested as follows. As a control, 200 g. of 0.1% anionic dodecyl benzene sulfonate in water was stirred at ambient temperature in a glass measuring column for 1 minute at 1000 rpm and developed a foam head of 10 cm. Stirring was then discontinued and the liquid left to stand for 1 minute. The foam head was unchanged after 1 minute standing time. The above procedure was repeated except that 0.1 % of the above liquid composition was added to the sulfonate before stirring. After stirring this mixture for 1 minute, only 1.5 cm of foam head developed and after 1 minute standing time, the aqueous sulfonate solution was completely defoa ed. EXAMPLE 2

The antifoaming test of Example 1 was repeated except that a methacrylic acid methyl ester photopolymer in 0.85% Na₂C0₃, was substituted for the foamable sulfonate. The results were as follows cm

(d) Initial foam head of photopolymer in absence 3.1 of Composition A

(e) Foam head of (d) after 1 minute 2.8

(f) Initial foam head of photopolymer containing 0.1 0.1% of Composition A

(g) Foam head of (f) after 1 minute 0.0

EXAMPLE 3

Example 1 was repeated except that ethoxylated (9 moles) nonyl phenol was substituted as the foamable liquid. The results were as follows.

cm

(k) Initial foam head of the foamable 3.5 liquid alkoxylated phenol in the absence of the antifoaming composition

(1) Foam head of (k) after 1 minute 3.2

(m) Initial foam head of the foamable liquid 0.5 after incorporation of Composition A

(n) Foam head of (m) after 1 minute 0.0 EXAMPLE 4

The following composition X was mixed for 5 minutes at ambient temperature under atmospheric conditions in a 200 ml glass beaker.

(o) 50.0 g. of propoxylated (4 moles) polyethoxylated (8 moles) - polypropoxylated (12 moles) mixture of C₆ to C₁₀ linear alcohols

(p) 49.0 g. of polypropylene glycol (MW 4,000) (ALKAPOL 4000) and

(q) 1.0 g. of hydrophobic silica (QϋSO WR-83)

The antifoaming property of the above composition was tested as follows. As a control, 200 g. of 0.1% anionic dodecyl benzene sulfonate in water was stirred at ambient temperature in a glass measuring column for 1 minute at 1000 rpm and developed a foam head of 10 cm. Stirring was then discontinued and the liquid left to stand for 1 minute. The foam head was unchanged after 1 minute standing time. The above procedure was repeated except that 0.1 % of the above liquid composition X was added to the sulfonate before stirring. After stirring this mixture for 1 minute, only 1.8 cm of foam head developed and after 1 minute standing time, the foam head of the aqueous sulfonate solution was 0.4. COMPARATIVE EXAMPLE 5

The following composition B was mixed for 5 minutes at ambient temperature under atmospheric pressure in a 200 ml glass beaker.

(h) 50 g. of polyethoxylated (7 moles) polypropoxylated (3 moles) C_g linear alcohol

(i) 45 g. of polypropylene glycol (MW 4,000) and

(j) 5 g. of hydrophobic silica (QUSO WR-83) .

The viscosity of this composition was 700 cps. When the hydrophobic silica was increased to 10% and component (i) reduced to 40%, the viscosity of the mixture increased to 2000 SUS which made pumping of the liquid composition difficult and led to deposits on the equipment. Also, dispersibility in the foamable liquid solution of dodecyl benzene sulfonate was markedly reduced. The foam head of the aqueous sulfonate solution was reduced only 35% (to 3.5 cm) using composition B.

The experiment illustrates the undesirable effect when excess ethoxylation with a short alkyl group is present in component (h) of Composition 3.

EXAMPLE 6

The procedure in Example 1 is repeated except that components (b) and (c) are omitted.

The results of the antifoaming test are as follows: cm Initial foam head of the aqueous sulfonate solution in the absence of (a)/foam head after 1 minute 10/10

Initial foam head of the aqueous sulfonate solution in the presence of 0.1% of component

(a)/foam head after 1 minute 4.5/4.0

EXAMPLE 7

The procedure in Example 1 is repeated except that components (a) and (c) are omitted. The results of the antifoaming test are as follows.

cm

Initial foam head of the aqueous sulfonate solution in the absence of (b)/foam head after 1 minute 10/10

Initial foam head of the aqueous sulfonate solution in the presence 0.1% of component (b)/foam head after 1 minute 4.3/3.8

Claims

WHAT IS CLAIMED IS:

1. A defoaming/antifoaming liquid composition having a cloud point less than 35 and containing

CH,

RO-(CH₂CHO)_χ(CH₂CH₂0)yH

or

or mixtures thereof;

CH,

HO(CH₂-CHO)₂H

and

wherein R is linear or branched chain alkyl having from 4 to 22 carbon atoms or mixture thereof; x has a value of from 2 to 20; y has a value of from 0 to 15 and z has a value of from 10 to 200; with the proviso that, when the number of carbon atoms in R is less than 11, the value of x exceeds the value of y.

2. The composition of Claim 1 wherein component (a) and component (b) are each present in the mixture in an amount between about 35 and about 65 weight % and the concentraition of the silica is between about 0.5 and about 8%.

3. The composition of Claim 1 wherein said mixture has a viscosity of between about 100 and about 3,000 cps.

4. The composition of Claim 3 wherein the mixture has a viscosity of not more than 500 cps.

5. The composition of Claim 1 which has a cloud point between about 1 and 35.

6. The composition of Claim 1 wherein component (a) is a mixture of propoxylated and ethoxylated C₁ to C₁₄ alkanols and where x has a value of 7 and y has a value of 5.

7. The composition of Claim 1 wherein R of component (a) is a mixture of propoxylated, ethoxylated C₆ to C₁₀ alkanols and where x has a total value of 16 and y has a total value of 8.

8. The process of adding an effective antifoaming/defoaming amount of the composition of Claim 1 to a liquid subject to foaming.

9. The process of Claim 8 wherein between about 0.001% and about 3% by weight of the composition is added to said foamable liquid.

10. The process of adding an effective defoaming amount of the composition of Claim 1 to the air/liquid interface of a foamed liquid.

11. The process of Claim 10 wherein between about 0.001% and about 3% by weight of the composition is added to the foamed liquid.

12. A foamable liquid containing from about 0.001% and about 3% by weight of the mixture of Claim 1.

13. The foamable liquid of Claim 12 containing from about 0.005% to about 0.5% by weight of said mixture.

14. The process of contacting a swellable polyme with an antiswelling amount of the composition of Claim 1.

15. The process of Claim 14 wherein the swellable polymer is polyyinyl halide.

16. The product of the process of Claim 14.

17. The product of the process of Claim 15.