FI58441B - KVARTSBASERAD ANTISKUMKOMPOSITION SAMT FOERFARANDE FOER FRAMSTAELLNING AV DENSAMMA - Google Patents

Description

ΓβΊ KU ULUTUSJULISISUU c QA Λ Λ ΑΓα Lbj (11) utlAggningsskript 5 o 4 4 1 c (45) - - - "^ y ^ (51) Kv.lk?/lntCU3 B 01 D 19/04 FINLAND —FINLAND (21) P »t« nt «i * ekn» »» f 98T / 71 * (22) Hakamliptlvi — Aiweknlnftdat 29-03-7 ^ (23) Alkuplivi — Glttlfh «t * dt | 29.0 3.7 ^ (41) Tullut JulklMksI - Bllvlt off * ntll »30.09.75

National Board of Patents and Registration (44) NlhtMtol | eBW, „

Patent · och registerttyralsan 'Amekan uttagd och uti. * Krtft «n tree lines 31 * 10.60 (32) (33) (31) Catch requested — Bugird prlorlm (71) Diamond Shamrock Corporation, 1100 Superior Avenue, Cleveland, Ohio, USA ( US) (72) Joseph Vincent Sinka, Mendham, NJ, Irwin Arnold Lichtman, Oradell, NJ, USA (71 *) Berggren Oy Ab (5U) Quartz-based antifoam compound and method for its preparation - Kvartsbaserad antiskumkomposition sarat förfarande för framställning av dens

The present invention relates to stabilized silica-based antifoam compositions, more particularly to an antifoam mixture of an aqueous system containing 3 to 20% by weight of hydrophobic silica suspended in a carrier liquid.

Silica-based antifoams are well known as antifoams in aqueous systems. However, one difficulty with such antifoams is the tendency of the silica particles to separate from the liquid (usually a hydrocarbon or natural oil) in which they are suspended. Only the use of silica particles with a very fine structure provides some degree of stability. However, finely divided silica is difficult to obtain and is more expensive than other grades of silica.

Rapidly cooled amides are also well known antifoams in aqueous systems. In addition, it is known to use mixtures of silica and rapidly cooled amides, both of which are used in antifoam amounts.

The following patents disclose the antifoam properties of the various 2,544,41 ingredients of the compositions of the invention, but have not previously disclosed the use of their combinations to increase the stability of silica-based antifoams.

U.S. Patent No. 3,076,768 discloses silica-based antifoams containing hydrophobic silica, hydrocarbon oil and a disintegrant.

U.S. Patent No. 3,207,698 discloses silica-containing antifoams that contain certain types of hydrophobic silica and hydrocarbon oil.

U.S. Patent No. 3,652,453 discloses amide-based antifoams containing rapidly cooled amides, hydrocarbon oil and oil-soluble organic polymers.

U.S. Patent No. 3,677,963 discloses amide-based defoamers containing rapidly cooled amides, hydrocarbon oil, oil-soluble organic polymers and fats.

Finnish patent 54058 discloses an antifoam mixture comprising bis-amide, liquid hydrocarbon oil, finely divided hydrophobic silica particles and silica oil. Silicone oil acts as a defoamer and hydrophobic silica particles act as a viscosity reducing agent. The patent does not discuss the deposition of silica particles, much less how to avoid it and increase the stability of the mixture. The purpose of the bis-amide in the mixture is not discussed at all and the use of the quick-cooled amide is not suggested in any way.

The antifoam compositions according to the invention are mainly characterized by the presence of a rapidly cooled amide in an amount of 0.1-2.0% by weight to stabilize the suspension of hydrophobic silica and carrier liquid, and optionally an oil-soluble organic polymer in an amount of up to 25% by weight and optionally surfactant 3.0% by weight, the percentages by weight being based on the weight of the antifoam mixture.

Silica must be rendered hydrophobic by roasting with silicone oil or otherwise. The hydrophobic silica and oil correspond almost entirely to the antifoam properties of the mixtures.

The amide, which must be rapidly cooled, as described above, is used only to stabilize the antifoam mixture. In other words, it has surprisingly been found that adding a small amount of rapidly cooled amide stabilizes the antifoam by keeping the silica particles in suspension for significantly longer than when not used. It is natural that the rapidly cooled amide also has antifoaming properties on its own. However, the amount of rapidly cooled amide used is not sufficient to substantially increase the effectiveness of the antifoam.

“58441

The antifoam compositions according to the invention can be prepared simply by mixing together completely pre-prepared ingredients or they can be prepared partially in situ.

The compositions of the invention are useful to some extent in almost all aqueous systems where foaming causes difficulty. Such uses include boiler water, sugar cane cleaning, papermaking, textile manufacturing, adhesives, cement and coatings. These antifoam compositions are very useful for preventing the formation of foam in a black liquor obtained in the pulp industry and for preventing air from entering water-based paints and adhesives.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION A. Ingredients 1. Hydrophobic silica

A hydrophobic silica useful in accordance with this invention can be prepared from any well-known form of silica, such as (1) a silica aerogel, colloidal silica, which can be prepared by displacing water from a liquid hydrogel gel above the critical temperature and then depressurizing the autoclave, (2) the so-called. "silica fume", which is a colloidal silica obtained by burning silicon tetrachloride and recovering the silica smoke formed; , such as when adding sodium ions to sodium silicate solution; similarly, aluminosilicate, copper silicate, magnesium silicate, zinc silicate, etc. Almost any quality and size of silica can be used, although finer particles are most preferred. Hydrophilic inorganic particles that could be expected to be silica substitutes such as calcium hydroxide, magnesium hydroxide, and calcium carbonate were found to be unusable.

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Any suitable method can normally be used to treat hydrophilic silica to make it hydrophobic. One method that has been found to be highly satisfactory involves spraying silica with silicone oil and heating at an elevated temperature of about 250-350 ° C for about 1/2 to 2 hours. The amount of silicone oil used can range from about 5 to 100% by weight based on the weight of the silica. However, amounts of about 7-25 # are usually satisfactory and most preferred.

The silicone oil may be a polysiloxane oil, such as an alkyl, aryl, alicyclic or aralkylsiloxane or polysiloxane having a viscosity of about 10-3000 centistokes at 25 ° 0. The most preferred silicone oils are alkylsiloxanes having viscosities of about 40-100 centistokes at 25 ° C. These alkylpolysiloxanes include dimethylpolysiloxane, diethylpolysiloxane, dipropylpolysiloxane, methylethylpolysiloxane, dioctylpolysiloxane, dihexylpolysiloxane, methylpropylpolysyloxysiloxane, methylpropylpolysiloxane,

Fine silica can also be made hydrophobic by treatment with an organic silicon halide or a mixture of organic silicides. Examples of suitable organic silicon halides are disclosed in U.S. Patent Nos. 2,306,222 and 2,412,470 and include alkyl (methyl), aryl (phenyl), alkaryl (tolyl) and aralkyl (phenylmethyl) silicides. . The treatment can be carried out by mixing the finely divided material in a closed vessel in the presence of vapors of the treatment material, e.g. methyldichlorosilane. The amount of treatment material and the length of treatment depend on the surface area of the inorganic material and the nature of the organosilicon halide used. In general, it is satisfactory to use about 5-15% by weight of the treatment agent based on the weight of the silica and a treatment time of about 1/2 to 2 hours.

Another method of making silica hydrophobic is to disperse it in silicone oil, i. at a concentration of about 2-10 ° C, and heating the resulting dispersion at a temperature of about 250-300 ° C for about an hour. The hydrophobic silica can then be extracted by centrifuging the mixture after dilution with hexane or the like as a solvent and drying the solid obtained.

The average particle size of the hydrophobic silica used is preferably less than about 10 microns, and even more preferably less than about 5 microns. Most preferred is an average particle size of about 0.02 to 1 micron. * 2. Carrier liquid

Any carrier that is inert to other ingredients, immiscible with water, liquid at room temperature and atmospheric pressure, and has a viscosity of about 30-400 SUS (Saybolt Universal Seconds, 38 °) can be used as the carrier liquid.

Although any substance that meets the above requirements can be used, the most preferred carrier fluids are natural oils, mineral oils, and hydrocarbons.

Examples of the most preferred carrier liquids include the following, but other liquids may also be used: mustard seed oil, castor oil, rice oil, soybean oil, corn oil, mineral titanium oil, Stoddard solvent, petroleum naphthene, xylene, xane, hexane, toluene, naphthenic, naphthenic, mineral -ni, kerosene, etc. If desired, mixtures of two or more carrier liquids may be used. One highly preferred carrier liquid is paraffin mineral oil.

It should be noted that when a carrier liquid is used for rapid cooling of an amide, its minimum boiling point should be at least equal to the melting point of the amide and it should have an average of about 6 to 25 carbon atoms.

3. Rapid Cooled Amide Stabilizer Several amides are useful in the present invention provided that they are rapidly cooled as set forth below.

Useful amides are those obtained by reacting a polyamine containing at least one alkylene group having 2 to 6 carbon atoms with a fatty acid having 6 to 18 carbon atoms. An example is an amide obtained from polyamine. When measured on the basis of the total oil absorption value of the particles, 125 (number of absorbed oil grams per 1-0 g of silica) has the lowest useful value and 170 or more is most preferred.

7 58441 and a reaction between a fatty acid or a mixture of fatty acids such as hexane, decanoic, lauric, palmitic, oleic and stearic acids, hydroxy acids such as castor oleic acid or naphthenic acids such as those obtained as by-products from the refining of petroleum. Naturally occurring fatty acid mixtures such as tall oil acids, tallow fatty acid and the like can also be used. Suitable amines include e.g. ethylenediamine, butylenediamine, diethylenetriamine, triethylenetetraamine, hexamethylenediamine, decamethylenediamine, hydroxyethylethylenediamine, 1: 3-diamine-2-propanol and the like. *

One useful amide can be prepared as follows.

95.7 parts by weight of bleached hydrogenated tallow fatty acids are fed to a stainless steel reactor equipped with a dieter, a water trap and a stirrer. The entire treatment, which involves the introduction of reactants and cooling of the reaction product, is carried out under a nitrogen atmosphere. The acid charge is heated to a temperature of about 165-175 ° C and 10.1 parts by weight of ethylenediamine are added with stirring. After the addition of the diamine, the reaction mixture is heated to a temperature of about 180-185 ° C. The mixture is allowed to react at a temperature of about 180-185 ° C until the acid number is less than 5 and the alkalinity is less than 0.6% by weight. The reaction product of ethylenediamine and tallow fatty acid obtained is cooled to room temperature. If desired, the cooled mass can be ground to obtain a product in the form of a very fine powder.

The rapid cooling method is substantially the same as that described in U.S. Patent Nos. 3,652,453 and 3,677,963, the disclosures of which are incorporated herein by reference. The difference between the rapid cooling methods in the above-mentioned patents and the process according to the invention is that according to the invention the amide is not combined with the other ingredients in the melt except for the carrier liquid. The flash cooling method comprises heating the amide above its melting point, keeping the amide in a molten state for at least 15 minutes, and flash cooling the amide: (a) adding a colder carrier liquid or water, (b) rapidly pouring the melt into a colder carrier liquid, or (c) adding the melt to a cold surface and adding a carrier liquid. Optionally, the amide may be mixed with a predetermined amount of carrier liquid prior to heating, where KMonoaxynins are not useful in this invention.

In the case of 8 58441, the mixture must be heated to a temperature at which the amide is completely dissolved and then kept at this temperature for at least 15 minutes. In either case, it is important that the amide be heated long enough for all of the crystalline elemental particles to decompose so that the amide can more easily assimilate the desired new crystal structure formed during the flash cooling process. The term "colder" means room temperature (22 °) or below.

4. oil soluble polymer

Almost all oil-soluble polymers are useful to some extent in this blend and include vinyl acetate copolymerized with ethylenically unsaturated comonomers such as maleic and fumaric acid esters, ethylene, propylene and butylene; polyalkylene oxide adducts such as methyl glucoside propoxylated with 4 moles of propylene oxide; glycerin propoxylated with 15 moles of ethylene oxide and 45 moles of propylene oxide; a copolymer of lauryl methacrylate and vinylpyrrolidone; methacrylate copolymers dissolved in a solvent-purified (100 SUS 3 ° C) neutral oil and phenol-modified coumarone-indene resins. These materials can be used as such or in admixture with each other.

A preferred oil-soluble polymer is a copolymer of vinyl acetate and fumaric acid esterified with tallow alcohol. Such an oil-soluble polymer is sold by Enjay Chemical Co. in the form of its mineral-oil solution under the trademark "Paratone 440" containing about 25 parts by weight of said copolymer in 75 parts by weight of a liquid hydrocarbon. This product has the following features:

Viscosity at 98.9 ° C, cS 1300

Flash point, CPC, 0 ° C 1Ö2 Color, ASTM 40

Specific gravity at 15.6 ° C 0.92

Another preferred oil-soluble polymer is a copolymer of styrene and polyester. Such an oil-soluble polymer is prepared by The Lubrizol Corporation in the form of its paraffin oil solution under the trademark "Lubrizol 3702" containing about 30 parts by weight of said copolymer in 70 parts by weight of a liquid hydrocarbon. This product has the following features: 9 58441

Viscosity at 98.9 ° C, SUS 3800

Viscosity at 98.9 ° C, cSt 815

Specific gravity at 15.6 ° C 0.905

Another preferred oil-soluble polymer is a copolymer of alkyl methacrylate and N-vinylpyrrolidone. Such an oil-soluble polymer is prepared by the Rohm and Haas Company in the form of its neutral oil solution under the trademark "Aeryloid 966" containing about 30 parts by weight of said copolymer in 70 parts by weight of a liquid hydrocarbon. This product has the following features:

Viscosity at 98.9 ° C, SUS 3730

Viscosity at 98.9 ° C, cSt 800

Flash point, COC, ° C 192.5 Color, ASTM 3

Specific gravity at 15.6 ° C 0.899 When using an oil-soluble polymer, the amount of hydrophobic silica can be reduced to about 4-7% by weight in order to reduce the viscosity. The antifoam efficiency of the mixture remains the same despite the reduction. The compositions of the invention have a satisfactory viscosity range of 200-2000 es, most preferably 400-600 es. 1

Surfactant additives

Any surfactant additives useful in this invention may act as disintegrants and / or emulsifiers and may be anionic, cationic or non-ionic. The amount of type of surfactant used depends to some extent on the quality of the system in which it is used. In general, anionic agents appear to provide the best antifoaming effectiveness and are most preferred. Examples of suitable anionic agents include fatty acids containing about 12 to 22 carbon atoms, such as steric acid, and soaps for these fatty acids, such as alkali metal, alkaline earth metal, aluminum, ammonium and amine soaps, e.g. triethanolamine stearate, as well as puuhartsisaippuat. Soaps can be added as is or formed in situ. Examples of other suitable anionic agents are alkali metal salts of alkylarylsulfonic acids, sodium dialkylsulfosuccinate, sulfated or sulfonated oils, etc., sulfated castor oil, sulfonated tallow and alkali metal salts of short chain petroleum sulfonic acids.

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Examples of suitable cationic substances are salts of long-chain primary, secondary or tertiary amines, such as oleylamine acetate, cetylamine acetate, didodesylamine lactate, quinearoyldiethylenetriamineteamineteaminate, 2-dipuryl triethylamine-acetyldiaminetetramine. phate, cetylpyridinium bromide, hexadesylethylmorpholinium chloride and diethyldododesylammonium chloride.

Examples of suitable nonionic substances are silicone oils as defined above, condensation products of higher fatty alcohols with ethylene or propylene oxide, such as reaction products of butyl alcohol with a propylene oxide unit or reaction products of cetyl alcohol with isoethylene oxides of ethylene oxide, such as ethylene oxide, higher fatty acid amides, condensation products with 5 or more ethylene oxide units, the long-chain fatty acids, polyethylene glycol esters, such as tetraetyleeniglykolimonopalmitaatti, heksaetyleeniglykolimono laurate, nonaetyleeniglykolimonostearaatti, nonaetyleeniglykoli dioleate, tridekaetyleeniglykolimonoarakidaatti, trikosaetyleeni-glykolimonobehenaatti, trikosaetyleeniglykolidibehenaatti, polyhydric, the alcohol partial higher fatty acid esters of ethylene oksidikondensaatiotuotteet and within these anhydrides(mannitol anhydride and sorbitol anhydrate) such as glycerol monopalmitate reacted with 10 molecules of ethylene oxide, pentaerythritol monooleate reacted with 12 molecules of mannitone oxide ethylene oxide, sorbitan monostearate reacted with 10 molecules of ethylene oxide, sorbitan monostearate reacted with 10 to 15 molecules of ethylene oxide, long-chain polyglycols in which the hydroxyl group is esterified with a higher fatty acid and the other hydroxyl group is esterified with a lower alcohol, such as methoxy polyethylene glycol 550 monostearate (550 means polyglycolate) Combinations of two or more surfactant additives may be used provided that the anionic agents are not mixed with the cationic agents.

B. Preparation Method 1. Partial In Situ Method 11 5 8 4 41 In this method, hydrophobic silica is first mixed with a carrier liquid that has been heated to keep the silica particles in suspension. The suspension is then cooled to room temperature or below, and the amide (optionally containing some carrier liquid) which has been melted and held in melt for at least 15 minutes is rapidly cooled by rapidly adding it to the suspension. The suspension / amide mixture is then homogenized at room temperature at a pressure of 70-350 kp / cm 2, preferably 105-228 kp / cm 2 and very preferably at a pressure of about 210 kp / cm 2. Homogenization can also be carried out when the mixture is at a higher temperature, in which case the pressure can also be higher. Unexpectedly, it has been found that homogenization can be performed at a higher pressure in the case of a silica / carrier liquid / amide mixture than in the case of a carrier liquid / amide mixture. After homogenization, an oil-soluble polymer and a surfactant additive may optionally be added.

2. Simple Mixing Method In this method, hydrophobic silica is first mixed with a carrier liquid that has been heated to keep the silica particles in suspension. The suspension is then cooled to room temperature. The amide, which has already been rapidly cooled separately, is then simply mixed with the suspension and the mixture is homogenized and the optional ingredients are added in the same manner as in the partial in situ process. Alternatively, the flash-cooled amide-carrier liquid mixture and the silica / carrier liquid mixture can be homogenized separately and then mixed together, in which case further homogenization is not necessary.

C. Ingredient parameters and method of manufacture

All of the following ingredients are expressed as weight #s based on the 100 # mixture.

The hydrophobic silica should be present in an amount of about 3-20% and preferably about 4-11%.

The quenched amide should be present at about 0.1-2.0% and preferably about 0.8-1.2%.

the oil soluble polymer may always be present at about 25% and preferably about 8-12%.

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The surfactant additive may always be present in an amount of about 3.0% and preferably about 0.5-2.5% ·

The carrier liquid is present in an amount that forms the difference between all of the above ingredients and the entire mixture.

D. Typical mixtures of the invention

Example I

9 parts (36 g) of hydrophobic silica having an average particle size of 22 millimicrons were added to 75.5 parts (302 g) of paraffin mineral oil heated to 100 ° C. After stirring, the mixture was cooled to room temperature (about 22 ° C) to form a suspension of silica in oil with limited stability. Half a part (2.0 g) of the amide formed by the reaction product of ethylenediamine and tallow fatty acid was separately mixed with 15 parts (60 g) of mineral oil heated to 140 ° C and kept at this temperature for 15 minutes. The 140 ° C amide / oil mixture was then flash cooled by rapidly adding it to a 22 ° C silica / oil suspension to form a mixture of hydrophobic silica, flash cooled amide and mineral oil. The mixture was then homogenized to obtain a homogeneous suspension.

Example II

The mixture was prepared according to Example I except for the following. 10 parts of silica were suspended in 75.5 parts of mineral oil, 1.0 part of amide was melted with 10 parts of mineral oil, 2.0 parts of propoxylated butanol (30 P.O.) were added before homogenization and 0.3 parts of silicone oil were added after homogenization to a surfactant.

Example III

(a) The mixture is prepared according to Example I except for the following. 5 parts of silica were suspended in 71.7 parts of mineral oil, 1.0 part of amide was melted with 10.0 parts of mineral oil and 2.0 parts of propoxylated butanol (30 P.O.) were added before homogenization.

(b) To the above mixture (a) were added 0.3 parts of silicone oil as a surfactant additive and 10.0 parts of an oil-soluble polymer ("Paratone" 440).

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Example IV

The mixture was prepared according to Example III except that the oil-soluble polymer was "Acryloid" 966.

Example V

The mixture was prepared according to Example III except that the oil-soluble polymer was "Lubrizol" 3702.

C. Applications 1. Paint production

The compositions of the invention are useful in the manufacture of latex and other water-based paints. The defoamer is preferred in paints to prevent the formation of bubbles formed by the air that has penetrated it as a result of handling, mixing, etc., and to contaminate the coated surface. The compositions of the invention may be added to the paint at any time during its manufacture in amounts ranging from 1.2 to 6.0 g / liter of paint and most preferably approximately 3.6 g / liter of paint.

Evaluation of these mixtures as antifoams in paints was performed as follows. An experiment to prevent foaming in the paint mixture was performed by adding the test mixture to a latex paint containing an antifoam and shaking in a Red Devil Mixer for 10 minutes. The shaken sample was then weighed and this weight was used to calculate the density of the paint and the volume of air infiltrated. These values were then compared to an unshaken paint that had been shaken without antifoam.

The experimental results obtained by the above method were as follows.

I. Shaking test using New London Mills paint SBR weighing 1.46 kg / l with shaking for 10 minutes using an addition of 0.3 kg / 100 l of antifoam.

Weight per liter Penetration- (kg) shake- Weight loss with sensed air

After antifoam (kg) percentage substance 0 1. Example III 1.452 0.035 0.55 2. Foamki11 639-C * 1.448 0.055 0.82 3. U.S. Pat. 3,207,698 1,440 0.09 1.37 1.212 1.15 17.00 4. None m 58441 Foam for use in i-Ials sold by Crusible Chemical Company as a liquid non-ionic substance with a flash point greater than L49 ° C.

II. Shaking test using Conchemco's Deep Base No. 6212 paint, weight 1.045 kg / l, shaken for 5 minutes after the addition of 0. 6.kg/100 l of antifoam.

penetrating

Antifoam Weight per Weight loss without pro- substance liter (kg) (kg) cent 1. US-pat. 1.008 0.17 3.54 3,207,698 2. Example III 0.972 0.33 6.98 3. Pales' 0.923 0.55 11.68

No-Fo 4. None 0.596 2.04 42.90 yen. ·

Commercially available defoamer for paints.

III. An additional test for the appearance of the film was performed using Conchemco's Deep Base No. 6212 (samples standing at 49 ° C for 1 week) with an added amount of 0.6 kg / 100 L.

Antifoam- Bubble Disintegration- Dry Film Appearance_Material Speed Bubbles Recesses Pores 1. U.S. Pat. fast traces traces very 3 207 698 little compliant 2. Example III moderate few moderate moderate 3. Fales' No-Fo very several several several slow 4. None very very very very slow abundant abundant abundant 2. Adhesives

The compositions of the invention can also be used in the preparation of animal glue and other water-based adhesives. The antifoam is preferably used in adhesives to prevent a reduction in the surface contact area caused by air bubbles penetrating them and a deterioration in the adhesion of the adhesive as a result. The compositions of the invention may be added to the adhesive compositions during the mixing of the ingredients in amounts of 0.05 to 0.5 (and preferably 0.1 to 0.3) parts by weight per 100 parts by weight of the solids of the adhesive.

The evaluation of the mixtures as antifoams in the adhesives was as follows. All parts are by weight unless otherwise indicated.

40 parts of animal glue were combined with 60 parts of water at 60-71 ° C. While stirring at the same reasonable rate, 3 or 4 drops of phenol were added to this mixture. 35 parts of corn syrup were added to 65 parts of the above mixture at the above temperature while stirring. After thorough mixing of all the ingredients, the stirrer was made to rotate rapidly, at which time 0.5 part of the antifoam to be tested was introduced into it. Stirring at high speed was continued for 5 minutes (temperature 65.5 ° C) after which the sample was set aside to cool without disturbance. After reaching room temperature, bubbles and other surface irregularities were examined from the obtained gel surface.

The experimental results using various antifoams in the above experiment were as follows.

The appearance of the antifoam surface is reduced by the appearance of the antifoam. 4 Wax and PEG 400 stearate moderately mixed 5 Numbers 2 and 3 5: 1 mixture moderately 6 Hydrophobic silica and several moderately polyoxyalkylene base mixture 7 Polyoxyalkylene and aluminum several mixed ums te araat t ipe rus mixture 1 2

Same as No. 3, but using several different emulsifiers 2

Nothing very very much much 3. Paper making

The compositions of the invention are also useful in reducing the foam present in 16 5 8441 (quenching the foam) and preventing the formation of foam (prevention of foam) which occurs in the black liquor during cooking. When used for this purpose, about 0.003 to 0.5 parts by weight of solid defoamer is added to the pulp per 100 parts by weight of dry pulp.

The following equipment and test method. was used to determine the effectiveness of the various ingredients in extinguishing the foam formed and preventing the formation of foam in the black liquor. However, the apparatus and method could also be used to test any liquid that forms a foam when stirred and / or heated.

A 1000 ml goblet was used as the main vessel for the test liquid. A curved glass tube fused to the bottom of the goblet was connected to a centrifugal pump by means of a rubber hose. The pump was used to continuously circulate the test solution from the cup to the pump and back to the cup. Pumping was performed at such a rate that the test liquid entering the beaker mixed the liquid in the beaker to the extent that foam formed. The pumping rate was approximately 0.9 kg per minute. The test solution enters the beaker at a point about 6 cm above the surface of the liquid in the beaker and strikes the surface of the liquid in the beaker at an angle of 90 °.

When performing the antifoam mixture experiment, 500 ml of freshly obtained concentrated black liquor was introduced into a beaker at a temperature of approximately 75 ° C. This liquid fills the goblet at a height of about 8.3 cm from the bottom when at rest. This level is denoted and called the zero level. In the anti-foaming test, 0.1 ml of the antifoam mixture is added to 500 ml of liquid in the beaker. The pump and stopwatch are started at the same time. The height of the foam above the zero line is measured at 15-second intervals within the first minute, then at 30-second intervals, and the results are recorded. In the defoaming test, the liquid is mixed and heated before the defoaming mixture is added. After the foam has risen to 8 cm, add 0.1 ml of the antifoam mixture to be tested and record the values as described above.

Using the above method, the following results were obtained.

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18 58441

The above experiment clearly shows that adding the amount of rapidly cooled amide to a point where it can be assumed to have antifoam efficiency is not useful. This indicates that the rapidly cooled amide is clearly not used in this invention due to its known antifoam property. In reality, it should be noted that the combination of known antifoams, hydrophobic silica and flash-cooled amide, not only synergistically increases the antifoam efficiency but actually decreases it.

D. Stability The purpose of this experiment was to test the efficacy of stabilized compositions falling within the scope of the invention compared to compositions using other stabilizers and non-stabilized hydrophobic silica antifoams.

The centrifuge containing the various mixtures * was rotated for 1 hour at 1000 rpm. The centrifuge test tubes were each filled to a height of 106 mm with the test mixtures. The mixtures according to the invention, if they separated at all, usually made it into three phases: an oil at the top, an oil and a quick-cooled amide in the middle, and silica at the bottom and some oil. The mixtures, which did not contain flash-cooled amide, separated into two phases: oil at the top and silica at the bottom, as well as some oil. The first number in the following table indicates the height of the silica-free layer or layers. The second number indicates the viscosity of the mixture before centrifugation.

All silicas used in the following experiment were hydrophobic and were within the scope of the invention (unless otherwise noted). It can be seen that although fine and medium particle size silicas are most preferred, large particle sizes can also be used depending on the choice of quick-cooled amide. In this experiment, high particle size silica was in fact an agglomerate of medium particle size particles.

The first two amides in the following experiment are quick-cooled and are within the scope of the invention. The third amide is not flash cooled.

Since a more viscous medium is generally considered to hold the particles better in suspension than a lower viscosity, the viscosity (number in parentheses) of each mixture was measured. The mixtures were prepared using polybutene as a thickener. Although these mixtures were relatively stable, it should be noted that very large amounts of polybutene were required (25 and 21%, respectively). A mixture was also prepared using fine particle size hydrophobic silica as a thickener. Although this mixture was relatively stable, it should be noted that such silica is very expensive and difficult to obtain. In fact, one of the advantages of the invention is that no fine silica is required to provide stability. Viscosity values (in parentheses) indicate that high viscosity alone is not sufficient to stabilize the silica suspension. This is evident from reference stabilizers Nos. 2 and 6 combined with finely divided silica and stabilizers Nos. 2 and 4 combined with medium-particle silica.

When comparing values, this must be done vertically, i.e. between different stabilizers when using the same silica. The larger the silica, the more difficult it is to stabilize. As a result, a height of 2 or less is satisfactory in the case of finely divided silica, a height of 5 or less is satisfactory in the case of medium-sized silica, and a height of 10 or less is satisfactory in the case of high-silica particles.

Combined height of one and two phases (viscosity)

Silica (9%) - particle size - (oil

Stabilization absorption - g / 100 g) __, _, __ substance (1¾) Fine (250) Medium (170-190) Large (125-165) 1. ethylene- 0 (1600) 2 (1200) 10 (1300) diamine stearic acid diamide (flash-cooled) 2. ethylene-1 (320) h (80) 70 (60) triamine oleic acid diamide (flash-cooled) 3. same as ~13 (250) in 1, but not quick-chilled. polybutene- 0 (860) ä (^ 60) xx - ni (thickener)

Claims (3)

20 5 8 4 41 (table continues) 5 · 1.5% fine silicon - 2 (840) oxide (hydrophilic) 6. none 3 (360) 20 (160) 70 (100) * 25% polybutene * * 21% polybutene 1. An antimony composition for a water-based system and in the range of 3-20% by weight of hydrophobic kieselguhr suspended in a barrier-free form, which can be added to the amine in a game of 0.1-2.0% by weight of hydrogenation in suspension kieselguhr och bärarvätska, eventuellt en oljelöslig organicisk polymer i en mängd av upptill 25 viktprocent och eventuellt et ytaktivt medel i en mängd av upptill 3,0 viktprocent, paints viktprocenttalen är beräknade pä antiskumningskomposi-tionens vikt. Antifoam mixture of an aqueous system containing 3 to 20% by weight of hydrophobic silica suspended in a carrier liquid, characterized in that a rapidly cooled amide is additionally present in an amount of 0.1 to 2.0% by weight to stabilize the suspension of hydrophobic silica and carrier liquid, and optionally oil-soluble organic polymer in an amount of up to 25% by weight and optionally surfactant in an amount of up to 3.0% by weight, the weight percentages being calculated on the weight of the antifoam mixture. 2. An antisense composition according to claim 1, which comprises the reaction of the reaction product with ethylenediamine and talc. Mixture according to Claim 1, characterized in that the rapidly cooled amide is the reaction product of ethylenediamine and tallow fatty acid. Anti-foaming composition according to Claim 1 or 2, characterized in that the hydrophobic silica oil has an absorption value of more than 170 g per 100 g of silica. Defoamer mixture according to one of Claims 1 to 3, characterized in that the carrier liquid is a paraffin mineral oil. Defoamer mixture according to one of Claims 1 to 4, characterized in that the oil-soluble organic polymer is a copolymer of vinyl acetate and fumaric acid esterified with tallow alcohol. Defoamer mixture according to one of Claims 1 to 4, characterized in that the oil-soluble organic polymer is a copolymer of styrene and polyester. 21 5 8441 Defoamer mixture according to one of Claims 1 to 4, characterized in that the oil-soluble organic polymer is a copolymer of alkyl methacrylate and N-vinylpyrrolidone. Process for preparing an antifoam mixture according to one of Claims 1 to 7, characterized in that the carrier liquid is heated to at least 100 ° C, after which hydrophobic silica is added in an amount of 3 to 20% by weight and mixed with the carrier liquid to form a temporary suspension which is cooled. to or below room temperature, that the amide, optionally mixed with the carrier liquid, is heated separately until the amide has melted or dissolved in the carrier liquid, that the amide temperature is maintained for at least 15 minutes and that 1.2.0% by weight of this amide is added to the suspension. separately, the mixture of hydrophobic silica, carrier liquid and the rapidly cooled amide is homogenized at a pressure of 70-350 kp / cm and that, after homogenization, n oil-soluble organic polymer in an amount of up to 25% by weight and possibly a surfactant in an amount of up to 3.0% by weight, all percentages based on the weight of the antifoam mixture. 3. Antiskumningskomposition enligt patentkravet 1 eller 2, kännetecknad av att den den hydrophoba kiseldioxiden har