FI74625B - FOERFARANDE OCH BLANDNING FOER ATT FOERHINDRA ELLER FOERMINSKA SKUMBILDNING. - Google Patents

Description

74625

Method and mixture for preventing or reducing foaming Förfarande och blandning för att förhindra eller förminska skumbildning

The invention relates to a process and a mixture for controlling, stopping or preventing the formation of foam in reactions in industrial aqueous solutions. In more detail, the invention provides a method and composition for controlling foaming which are particularly suitable for use in paper and pulp mills.

Excessive foaming, a feature of many aqueous transportation and processing systems in aqueous solution, is not desirable. Excessive foam tends to reduce the efficiency of the manufacturing machinery and thus increase the cost of the final product. One industrial water-solution mixture or environment with a long-standing problem caused by excessive foaming is in the processing of paper and pulp mills. Foaming (e.g. due to the presence of resin) occurs in pulp and paper mills at numerous sites, and many solutions have been proposed to control foaming. In general, the proposed solutions have been selected for specific applications at the plant. These items include a brown pulp washer in which hot cellulose is washed to remove the cooking solution mixed therewith; a filtration section in which the washed cellulose from the brown pulp washer is subjected to replacement washing and cooling before it enters a bleaching machine and a papermaking machine where the bleached cellulose becomes paper. In the former step, foaming usually occurs in an alkaline aqueous solution, while in the latter foaming usually occurs in an acidic aqueous solution.

CH Patent Publication 576,800 describes a method for preventing foam in the sugar or yeast industry. According to the method, the 74625 ethylene oxide / propylene oxide adduct is added in solution to a straight or branched chain saturated or unsaturated aliphatic alcohol. The specification discloses mixtures in which the moles of ethylene oxide (EO) are 3 to 10 and the moles of propylene oxide (PO) are 3 to 20 and the EO / PO ratio is between 0.25: 1 and 1: 1. Thus, the patent publication does not disclose a large number of moles of PO according to the invention (20 to 50 moles of PO). According to the prior art, not as good antifoaming effects are obtained as with the present invention.

According to CH Patent Publication 576,800, the components can be added either as a mixture or in series, but the publication does not in any way distinguish between the two ways and does not mention that serial addition would achieve a more favorable result.

The invention comprises a method for controlling foam in aqueous reactions in aqueous solution which have a tendency to foam, such as the reaction described above, which generally occurs in a paper or cellulose mill. The process comprises contacting an effervescent or optionally effervescent aqueous solution with an effective amount of antifoaming agent, which is described herein, which reaction then causes the foaming properties of the liquid to decrease, cease or be destroyed.

The invention is further defined in the appended claims and comprises a process which prevents foaming or foaming in an industrial aqueous solution which has a tendency to foam; the process comprises the step of adding to the solution an antifoam or antifoam or an antifoam amount in an amount effective to reduce or eliminate the antifoam. This defoamer contains a polyether chain consisting essentially of a polyethylene oxide (EO) "block" or a residue or condensate attached at one end to a poly-1,2-propylene oxide (PO) "block" or a residue having a hydroxyl group; at one end of the poly (EO) residue is an organic hydrophobic moiety or hydrophobic. So

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74625 would achieve a useful antifoam which is possible in the practice of this invention, the hydrophobic content should generally be about 3 to 50% by weight of the antifoam, the remainder being the polyether chain described above. Further, the PO / EO ratio in the polyether chain is generally greater than 1: 1 and is preferably about 3: 1. In general, the antifoam is suitably dissolved or mixed in a carrier which may be inorganic, such as water, or organic, such as mineral oil.

In the best practice of the invention, the aqueous solution is a paper or pulp mill processing stream in which foaming is due to the presence of wood resins, lignin sulfonates, surfactants or paper raw material additives and mechanically induced air proliferation.

In another good practice of the invention, the above-mentioned liquid antifoam mixture further contains an auxiliary amount of phosphorylated, synthetic or fatty alcohol mono-, di- or triester.

In another good practice of this invention, the antifoam composition described above further comprises a waxy agent such as pentaerythritol tetrastearate. Such a waxy substance has previously been used in antifoam compositions and has been found to be particularly useful in these.

As used herein, the term "inhibit" is intended to include any remedial or preventive measures that can be considered to eliminate the problems caused by excessive foaming, in particular to destroy, reduce or prevent foam as well as to reduce or eliminate increased air. increased air (which may comprise up to 15% of the volume of the processing stream that is vigorously mechanically agitated), the efficiency of the process is increased, although no appreciable change in the amount of surface foam can be observed with the naked eye before and after the addition of the antifoam. the term as used herein is intended to include monovalent, predominantly hydrocarbon moieties that are predominantly insoluble in water and generally have a molecular weight in the range of 100 to 350. As will be explained more fully below, the best hydrophobes have al alkylphenol moieties and high molecular weight saturated or unsaturated alcohols or mixtures thereof.

When applying po. a process for reducing or eliminating foaming of the reaction in aqueous solution, the substances described herein are optionally or actually mixed with an aqueous foaming solution (in an appropriate ratio), by virtually any desired or suitable method. The substances can be poured, sprayed or added into the foam or placed on the surface of the liquid, from which the substance thus reduces or removes the foam. Adding substances to a liquid that already has foam on its surface is another approach to considering this method.

Short definition of the chart

The diagram is a three-dimensional coordination description of the measurement of foam height as a function of antifoam composition. The horizontal axis refers to the weight percent of the 1,2-propylene oxide residue in the defoamer mixture relative to the total weight of the mixture. The left diagonal axis refers to the weight percent of the hydrophobic component relative to the total weight of the antifoam. The right-hand diagonal axis refers to the weight percent of the polyethylene oxide residue relative to the total weight of the defoamer.

Detailed Description of the Invention The antifoam compositions useful in this invention consist of nonionic polyethers having polyethylene

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5,74625 nitric oxide condensate residue or segment (-OC 2 H 4) x, attached to a poly-1,2-propylene oxide condensate segment (or a residue having a hydroxyl end, (-OC 3 H 6 -) yOH, a polyethylene oxide segment attached to an alkane, an organic moiety, such as a relative hydrophobic high molecular weight alcohol or mixtures thereof The antifoam compositions of this invention may be represented by the following structure:

R1- (OC2H4) x- (OC3H6) y-OH I

wherein R 1 is a monovalent organic hydrophobic moiety or hydrophobic, preferably one of the following: a long chain or high molecular weight primary or secondary alcohol, alkylphenol, or a mixture thereof; x is a number indicating the average number of ethylene oxide, in moles or units, per molecule of antifoam, having a numerical value of 3 to 20, preferably 5 to 15; y denotes the average number of propylene oxide, in moles or units, per molecule of antifoam, and having a numerical value of 15 to 60, preferably 20 to 50.

In order for the compositions described herein to achieve favorable antifoam properties, it has been found that both the relative amounts and the relative location of the EO and PO segment paths must be as described herein. Mixtures having the same relative amount of ethylene oxide and propylene oxide residues (i.e., the same weight percent) and in which ethylene oxide and propylene oxide are present in random segments are not useful defoamers and are not within the scope of this invention. Thus, the present invention contemplates the use of defoamers containing the organic hydrophobic described above in association with a segment or "block" of repeating ethylene oxide units (one that would be obtained by condensing an "x" mole of ethylene oxide into a chain by ring opening) which in turn is associated with another segment. to a "block" formed of repeating propylene oxide units (one which would be obtained by condensing γ moles of 1,2-propylene oxide) and having a hydroxyl end.

As mentioned above, very specific amounts of organic hydrophobics and EO and PO segments are required in the practice of this invention in order to achieve favorable foam control po. invention. In particular, when the preferred alkylphenol hydrophobia (such as nonylphenol) is used, it has been found that a particularly significant foam resistance is achieved (in a paper mill environment) if the polyether chain has an average of 12.5 repeating EO units, i. an average of 12.5 moles, and 25 to 60 PO units should be added to the chain to produce an antifoam.

The graph shows the criticality of the hydrophobic / EO / PO weight ratio in controlling foam caused by other surfactants.

The diagram shows in the three-dimensional coordinate system the relatively narrow limits of the antifoam composition which provide an antifoam property that can be exploited in the practical applications of this invention, in its preferred embodiment for a paper or pulp mill. The axes of the diagram show the weight percent of hydrophobic, polyethylene oxide residue and 1,2-propylene oxide residue, respectively, as described above. The numbers at the outer edge of the chart refer to the height of the foam in inches (centimeters), determined according to the experiment described below.

The description of the defoaming ability of defoamers is an internal test developed by the owner of the present invention. This experiment has been found to predict the defoaming ability of a given antifoam under actual industrial processing conditions (e.g., a paper mill).

Il 7 74625

Foam height measurements were made by adding about 100 parts per million (ppm) of the antifoam to be tested to three liters of 70 ° F (21 ° C) water in a metal 3-liter beaker with a temperature controller. The antifoam was dissolved or mixed in the preferred organic mineral oil carrier and contains about 80% by weight of crude oil and 20% by weight of antifoam. Thus, a complete antifoam mixture was added at a concentration of 500 ppm. The water in the beaker contained about 50 ppm of nonylphenol-EO, or an average of 9.5 moles per nonylphenol core. This alkylphenol-polyether surfactant is a high foaming surfactant commonly used in paper / cellulose processing processes, especially if simultaneous or subsequent deinking or purification of the cellulosic fiber is desired. Protruding from the top of the metal container is a transparent glass cylinder containing foam formed in the container. The glass cylinders have an external, vertical ruler for measuring the height of the foam column formed in the container. Located close to the open end of the glass cylinder and directed towards the metal vessel is a No. 30/15 "V-Jet" spray nozzle connected to a pressure-controlled water pump. The water pump circulates the contents of the beaker through the nozzle, thus not changing the concentration of the substances in the vessel. For the evaluations made here, a pressure of 6 psi (42 kPa) was applied to the nozzle by a pump. After a short period of time from the start of the pump, a constant foam height is produced in the glass cylinder, which is characteristic of the defoamer to be tested.

After starting the pump, the foam height readings were then taken once per minute for 15 minutes. The average of those 15 foam height values was then determined. An "acceptable" defoamer or defoamer or defoamer suitable for the purposes of this invention is an average foam height of 5 inches (12.7 cm) or less in 15 minutes. Acceptable ranges of defoaming power are shown in the diagram and are set between 4 and 5 inches (10.1 ... 12.7 cm). Comparing an aqueous solution of 50 ppm nonylphenol 8,74625 (EO) 9.5 without an antifoam mixture under the above conditions, it produced more than 9 inches (22.9 cm) of foam in about 2 minutes and caused pump cavitation and pressure loss.

To further enhance the antifoaming effectiveness of the blends of the claims herein, a separate series of antifoams in aqueous solution (i.e., no hydrocarbon carrier was used) was made. It was found that when the antifoams were suitably combined with a water-soluble carrier, similar antifoam ranges as in the diagram resulted. Since an organic mineral oil carrier is not essential to the effectiveness of this invention, antifoams can be mixed or dissolved in an organic or water-soluble carrier. However, antifoams did not perform as well in water as in organic hydrocarbon carriers, the antifoam was found to be less sensitive to small changes in PO / EO ratio in the organic environment. Thus, organic substances such as naphthenic oils, mineral oils, paraffin oils or kerosene are the preferred carriers in this connection. The most preferred carrier for the antifoam is a mineral oil, when the antifoam mixture contains 80% by weight of mineral oil and 20% by weight of antifoam.

Alkylphenol-polyether defoamers form a particularly desirable class of defoamer in this context. These alkylphenol-polyethylene oxide-hydroxyl-terminated polypropylene oxides are generally prepared from alkylphenol-polyethylene oxide starting materials. Alkylphenol-polyethylene oxide starting materials are a known class of surfactants that have been used for a long time in many different industrial processes. Such conventional substances have a structure

'\ Q) -' 0C2tV * -0H

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9 74625 wherein R2 is a straight or branched chain, saturated or unsaturated monovalent hydrocarbon radical of 6 to 18 carbon atoms, preferably 8 to 12 carbon atoms and may in the best sense be experimentally represented by the homologous formula CaH2a + 1 (preferably to a phenolic nucleus) associated with only one R2, but most R2s are within the scope of this invention); xs have a numerical value of 3 to 20 (preferably 5 .. .15), each (-OC2H4 -) - unit is derived from the opening of an ethylene oxide-din / \ CH2 "-CH2 ring, ethylene oxide is also known as oxirane. Alkyl chains are sometimes described herein as the term "Ca", where "a" is the number of carbon atoms in the chain, e.g., C12 or C12-14 »in the case of a mixture of chains.This description should be understood to describe any saturated or unsaturated, branched or straight chain hydrocarbon moiety wherein is a carbon atom In the case of a saturated species, "Ca" can be extended to mean the empirical formula CaH2a + i called C9H19 A particularly preferred group of starting materials for the synthesis of alkylphenol polyethers in this context are nonylphenol polyethylene oxides (NP-EO).

The nonylphenol-polyethylene oxides useful in this invention are characterized by a nine-carbon alkyl chain attached to an aromatic ring (in the ortho, meta or para position relative to the polyether chain), a hydroxyl-terminated polyether chain having 3 to 20 ethylene oxide units (i.e., the value of x is 3 to 20). If defoaming is considered in a paper and pulp mill environment, x preferably has a value of 5 ... 15, most preferably 8 ... 14. Where such common NP-EO mixtures can be synthesized as relatively pure fractions with relatively specific x values, they are generally sold as molecular mixtures with a range of 10,74625 x values. These mixtures are described by their average x value and thus the general substance is NP-E09f5 with an average of 9.5 ethylene oxide units (moles) per nonylphenol core (x = 9.5). Nonylphenol polyethylene oxides having an average x value of 3 to 20 are commercially available from several companies, e.g. G AF Corp. under the trade name "Igepal", Rohm and Haas Company under the trade name "Triton" and Jefferson Chemical Company under the trade name "Surfonic".

The present invention uses hydrophobic polyethylene oxide moieties having a plurality of 1,2-polypropylene oxide units attached to the outermost end of the polyethylene oxide chain (the polypropylene oxide chain is preferably hydroxyl-terminated, the antifoam structure is is positioned adjacent to the hydrophobic moiety in order to achieve the favorable antifoam properties that are possible in the practice of this invention.

The hydroxyl-terminated nonylphenol-polyethylene oxide-polypropylene oxides (ΝΡ-ΕΟχ-POy-OH) within the scope of this invention are prepared by methods well known to those skilled in the art. For example, NP-EOx-POy-OH can be prepared by reacting NP-EOx (e.g. "Igepal" or "Triton") with propylene oxide at e.g. 100 ° C to 150 ° C, 1 to 4 atm at atmospheric pressure, in the presence of an alkaline catalyst, e.g. KOH. U.S. Patent No. 3,021,372 (Dupre et al.) Describes in detail the preparation of the preferred hydroxyl-terminated octylphenol and nonylphenol-polyethylene oxide-polypropylene oxides; the information in the '372 patent is incorporated herein by reference. In general, it is desirable that the catalyst used in the preparation of NP-EOx-OH be not removed prior to the addition of PO segments (i.e., unneutralized NP-EO should be used). Another desirable group of nonionic surfactants that have been found to be useful in the practice of this invention are hydroxyl-terminated ethyl

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11 74 62 5 Lene oxide-propylene oxide-hydrophobic adducts with a high molecular weight or long chain alcohol, with the polyethylene oxide segment adding a higher alcohol to the polypropylene oxide segment. "High molecular weight" or "long chain" as used herein means a straight chain or branched, saturated or unsaturated, primary or secondary alcohol having from 6 to n. 24 carbon atoms, and generally has a molecular weight of about 75 to 300; these substances are called "fatty alcohols". Nonionic surfactants prepared from higher molecular weight alcohols can be described as follows:

R 3 (OC2H4) x (OC3H6) y OH

wherein R 3 is a straight or branched chain, saturated or unsaturated monohydric alcohol residue having from about 6 to about n in the alkyl chain. 24 carbon atoms (preferably 10 ... 18), the numerical values of x and y being the same as described above. Preferred hydrophobic long chain fatty alcohols for use herein are mixtures of C10-14 to C12-18 and C1-418 alcohols.

As described above, mixtures of hydroxyl-terminated higher molecular weight alcohols and EO-PO can be prepared by adding EO-PO polyether segments to alcohols having the desired carbon backbone. Alcohols useful in this context may be synthetic alcohols (i.e., prepared by known Ziegler or carbonylation methods) or alcohols generally prepared by reducing naturally occurring fatty acids to fatty alcohols. Useful fatty acid starting materials can be obtained from natural sources such as coconut oil, palm oil, tallow, Laard and tall oil. The length of the carbon chain and the structure of the alcohol are determined by the synthesis conditions or the nature of the fatty acid starting material used. Naturally, alcoholic structures can be obtained from natural sources by distillation or the like, or by the above-mentioned synthetic methods, followed by distillation. Particularly desirable higher alcohol-EO-PO adducts for use in this invention are synthesized by adding a (EO) 12.5 "(PO) 50 ~ OH" P ° ether chain to a mixture of C 1-6 C 3 -C 8 alkyl alcohols. the hydrophobicity of the compound can be described as C16 · C18 ·

In another desirable practical embodiment of the invention, the above-mentioned liquid antifoam is mixed with a mineral oil and further comprises an auxiliary amount of a phosphorylated mono-, di- or triester of a fatty or synthetic alcohol having the structure: 0 0 0

11 U H

R4-OP-OH, R4-OP-OH, R4-OPO-R5 IT »0 0 0 H f 1 R5 R5 in which R4, R5 and R5 may be the same or different and denote monovalent, fatty acid-derived or synthetic straight-chain derivatives. or branched, primary or secondary, saturated or unsaturated alcohol moieties.

Phosphorylated organic alcohols are prepared according to known methods to produce phosphoric acid esters, with the most preferred organic alcohol moiety being C 1-6 x 18 · Other alcoholic solutions that may be used are C 10-2 22 C 20+ or mixtures thereof. Thus, in the best case, the phosphorylated organic alcohol can be mixed with the antifoam described above and a carrier (e.g., mineral oil), and the mixture of antifoam, carrier, and phosphoric acid ester can be used in the same manner as the antifoam mixture alone.

In a third desirable embodiment of the present invention, the aforementioned defoamer mixture is mixed with petroleum or a synthetic waxy substance. A particularly desirable waxy substance is synthetic, non-petroleum-derived pentaerythritol tetrastearate. It must be emphasized that this

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13 74 62 5 The waxy substance can be used in addition to the above-mentioned foaming agent mixture (without or with a phosphorylated alcohol) for controlling the foam. A particularly desirable agent is available from Cyclo Chemical Company under the tradename Cyclochem PETS.

Many modifications and variations of the invention will become apparent to those skilled in the art without departing from the scope and spirit of the invention, and it should be understood that this invention will not be limited to the entities described and examples below.

Example 1

Preparation of hydroxyl-terminated nonylphenol (EO) x- (PO) y-OH

In a flushable, pressurized 2,000 gallon (7,500 L) stainless steel reaction vessel with a stirrer and temperature control mechanism is placed 1,614 pounds (732 kg) of nonylphenol. The nonylphenol is stirred (10 min.) While bubbling hydrogen through it. 45 pounds (20 kg) of potassium hydroxide are added to the nonylphenol, while the reaction vessel is purged several times (e.g. 3 times) with nitrogen and a small overpressure is left. At this point, the contents of the reaction vessel are heated to 230 ° F (110 ° C), at which temperature the reaction vessel is again purged with dry nitrogen and pressurized with nitrogen. Heating of the reaction mixture is continued to 250 ° F (120 ° C), after which the heating is stopped and the vessel is rinsed several times as described above. Approximately 3070 pounds (1390 kg) of ethylene oxide is added to the reaction vessel at a rate of 5 to 12 gallons (19 to 45 L) per minute and the addition, heating or cooling of the ethylene oxide is adjusted so that the temperature of the reaction mixture remains between 290 ° p + 1+ ° F (143 ° C + 5.5 ° C). The reaction vessel pressure should be kept below 60 psi (400 kPa) during the EO addition. Ethylene oxide is added to the point where nonylphenol-ethylene oxide has a cloud point in 1% aqueous solution (i.e., the temperature in 1% aqueous solution of the substance, 14 7 4 6 2 5 where the substance begins to "come out" of the solution, which appears as turbidity) between 127 ° F. .137 ° F (53 ° C ... 58 ° C).

After the EO addition is complete, the mixture is allowed to react at 290 ° F (143 ° C) for 15-30 min. Next, PO is added to a cloud point of 1% in a 20% diethylene glycol monobutyl ether solution for the EO-PO adduct at a temperature between 120 ° F and 123 ° F (48 ° C and 50 ° C). Continued addition of PO further lowers the cloud point of the adduct.

After the addition of PO, the complete product is cooled to 175 ° F (79 ° C) and 45 pounds (20.4 kg) of glacial acetic acid is added to the product to neutralize KOH, and the product is stirred for an additional 30 min. This complements the synthesis of the nonylphenol-EOgf5-P024-0H defoamer.

Nonylphenol was used to synthesize several surfactants of this invention using different amounts of EO and PO using a method similar to that described above. The antifoam ability of these surfactants was then measured according to the test described above. The results of this test are included in Table I.

li 15 74625

Table I

c9h19

- (EO) x (PO) y OH

Ratio Avg. numberSSrS Weight percent Foam height x / y x_ £ _ NP EO PO inches (cm) .17 1 6 34.1 7.4 58.5 5.0 (12.7) .08 1 12 21.5 4.7 73.8 6.0 (15.2) .06 1 18 15.7 3.4 80.9 5.9 (14.9) .04 1 24 12.4 2.7 84.9 6.1 (15.4) .53 6 29.7 19.3 51.0 4.7 (11.9) .25 3 12 19.7 12.8 67.5 5.4 (13.7) .17 3 18 14.7 9.6 75.7 5.3 (13.4) .13 3 24 11.8 7.6 80.6 4.9 (12.4) 2.17 6.5 3 30.6 43.1 26.2 8 + (20.3 +) 1.08 6.5 6 24.3 34.2 41.6 7.8 (19.8) .72 6.5 9 20.1 28.3 51.6 7.2 (18.3) .54 6.5 12 17.1 24.1 58.7 5.5 (13.9) .36 6.5 18 13.2 18.7 68.1 5.2 (13.2) .27 6.5 24 10.8 15.2 74.0 4.5 (11.4) .22 6.5 30 9.1 12.8 78.1 4.25 (10.7) 1.58 9.5 6 20.9 43.1 35.9 8 + (20.3 +) .79 9.5 12 15.4 31.7 52.8 8 + (20.3 +). . .53 9.5 18 12.2 25.1 62.7 8 + (20.3 +) .40 9.5 24 10.1 20.8 69.1 1.0 (2.5) .32 9.5 30 8.6 17.7 73.7 1.95 {4.9) .26 9.5 36 7.5 15.4 77.1 1.0 (2.5) .20 9.5 48 6.0 12.3 81.8 1.9 (4.9) .63 12.5 20 10.6 28.8 60.6 7.8 (19.8) .42 12.5 30 8.1 22.1 69.8 2.3 (5.8) .31 12.5 40 6.6 17.9 75.5 0.5 (1.3) .25 12.5 50 5.6 15.1 79.4 0.3 (0.7) ) 2.5 15 6 16.8 54.5 28.7 8 + (20.3 +) 1.25 15 12 13.0 42.3 44.6 8 ♦ (20.3 ♦) .83 15 18 10.6 34.6 54.7 8 + (20.3 ♦) .63 15 24 9.0 29.3 61.7 8 + (20.3 + ) 5.0 30 6 10.8 70.6 18.6 8 + (20.3 +) 2.5 30 12 9.1 59.5 31.4 8 + (20.3 +) 1.67 30 18 7.9 51.4 40.7 8 + (20.3 +) 1.25 30 24 7.0 45.3 47.8 8 + (20.3 +) 01 0 82.2 17.8 0 03 0 60.6 39.4 0 - 0 6.5 0 41.5 58.5 0 8 + (20.3 4) 0 9.5 0 32.7 67.3 0 8 + (20.3 ♦) 0 12.5 0 27.0 73.0 0 8 ♦ (20.3 +) 0 15 0 23.5 76.5 0 8 ♦ (20.3 +) 0 30 0 13.3 84.7 0 8 ♦ (20.3 ♦) 16 74625

Example 2

For comparison of antifoam properties, a group of substances having the following compositions (in weight percent) were prepared and tested.

1. C16-18- (EO) 5- (PO) 13 -OH 20.0 petroleum 80.0 2. nonylphenol- (EO) 12,5- (PO) 50 -OH 20.0 petroleum 80.0 3. water 63.5 petroleum 10.0 "Gantrex AN 149" * 1.5 nonylphenol- (EO) 9.5- (PO) 50 "OH 20.0 C16-18" 0PO3H2 5.0 * (maleic anhydride copolymer emulsion stabilizer sold by GAF Company) 4. petroleum 75.0 cyclohexanol 10.0 nonylphenol (EO) 12.5 “(PO) 50-OH 10.0

C16-18 “OP03H2 5.0 5. water 58.2 pentaerythritol trastearate 4.0 nonylphenol (EO) 12.5- (PO) 50” OH 10.0

Gantrex AN 149 2.0 sodium hydroxide 0.8 100 S.U.S naphthenic oil 25.0

All antifoam tests were performed with 160 ppm of the corresponding compound containing 100 to 600 ppm of nonylphenol- (EO) 9.5-OH - strong foaming surfactant. The results of this comparison are shown in Table II. The figures 11 17 7 4 625 denote the foam height one minute after each differential addition of the highly foaming surfactant.

Table II

Mixonylphenol- (EO) 9f5-OH, ppm its No. 100 200 300 400 500 600

Comparison 8+ 1 3/75 7.0 8.0 - 2 1.0 3.0 6.5 8.0 3 0.75 3.0 5.5 8.0 4 0.5 1.0 2.0 3.9 6.5 7.5 5 0 0.5 1.0 1.5 2.2 3.2 These foam height measurements in Table II were performed at 70 ° F (21 ° C) and 6 psi (41 kPa) pump pressure. . It should be noted that mixture 4, which is within the scope of this invention because it contains added phosphorylated C16-18 "long chain" alcohol, showed sufficient antifoaming ability. Mixture 3 (including Gantrez AN 149 as an emulsion stabilizer) is a stabilized oil-in-water emulsion that exhibits acceptable antifoaming ability at low concentrations of high foaming nonylphenol (EO) 9,5-OH. Mixture 5 (including Gantez AN 149) is another stabilized oil-in-water emulsion within the scope of this invention containing added pentaerythritol tetrasterate synthetic wax that exhibits the best antifoaming ability.

Example 3

Further experiments were performed using 100 ppm nonylphenol (EO) x- (PO) γ-OH material without rock oil (i.e., in water). 50 ppm nonylphenol- (EO) 9 # 5 ~ OH was used as a highly effervescent surfactant and 15 minute averages were measured at 70 ° P (21 ° C) in water at 6 psi (41 kPa). The foam barrier capacities (i.e., foam heights in inches (centimeters)) of 18,74625 are shown in Table III.

Table III

(Eo> x <poVoh

Value Foam height xy in inches (cm) 10 18 8 (20.3) 10 25 7 (17.7) 10 35 7 (17.7) 10 50 5.7 (14.5) 12.5 20 8 (20.3) 12.5 30 4.4 (11.2) 12.5 40 3.4 (8.6) 12.5 50 3.2 (8.1)

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Claims (17)

19 74625 A method of preventing foaming in an aqueous solution which has a tendency to foam, the method comprising the step of adding to the solution an antifoam amount effective to reduce or eliminate foaming, the antifoam consisting essentially of polyether chains containing polyethylene oxide groups and polyethylene oxide groups; that said polyether chain consists essentially of a polyethylene block or chain with an average of 3 to 20 moles of ethylene oxide (EO), the polyethylene oxide chain being connected at one end to a poly-1,2-propylene oxide block or chain having 20 to 20 moles of ethylene oxide. .50 moles of 1,2-propylene oxide (PO), wherein the ratio of moles of ethylene oxide to 1,2 moles of 1,2-propylene oxide (EO) :( PO) is at most about 0.5: 1, the propylene oxide chain being hydroxyl-terminated and the other end of the polyethylene oxide chain attached to an organic hydrophobic. Process according to Claim 1, characterized in that the ratio of moles of ethylene oxide (EO) to moles of 1,2-propylene oxide (PO) is at most about 0.42: 1. Process according to Claim 1 or 2, characterized in that the hydrophobic is alkylphenol. Process according to Claim 3, characterized in that the alkylphenol is nonylphenol. Process according to one of the preceding claims, characterized in that the polyether chain contains 5 to 15 units or moles of ethylene oxide. Method according to one of the preceding claims, characterized in that the solution is an aqueous processing stream of a paper or pulp mill. 74625 20 Process according to one of the preceding claims, characterized in that the antifoam further comprises a mono-, di- or tri-alcohol phosphate ester. Process according to Claim 7, characterized in that the ester is a mono-, di- or triphosphate ester of a C 16-18 alcohol. Method according to one of the preceding claims, characterized in that the antifoam further contains a waxy substance. Process according to Claim 9, characterized in that the waxy substance is pentaerythritol tetra stearate. The method of claim 10, characterized in that the antifoam further comprises a carrier. Process according to Claim 11, characterized in that the carrier is petroleum. A defoamer mixture for preventing foaming in an aqueous pulp or paper mill processing stream, characterized in that the mixture consists essentially of a) a defoamer having the structure R 1 - (EO) x (PO) γ-OH, wherein R 1 - is hydrophobic, comprising 3 to 50% by weight of defoamer, EO is an ethylene oxide residue, PO is a 1,2-propylene oxide residue, x is 3 to 20 and y is 20 to 50, with a x / y ratio of at most about 0.5: 1 ; (b) an organic or inorganic carrier; c) phosphorylated long chain alcohol; and optionally d) a waxy substance. II. 21 74 62 5 Mixture according to Claim 13, characterized in that it is an alkylphenol. Mixture according to Claim 13 or 14, characterized in that the value of x is about 5 to 15. Mixture according to Claim 13, characterized in that the carrier is petroleum. Mixture according to Claim 13, characterized in that the waxy substance is pentaerythritol tetrastearate. 74625 22