ITVA20130040A1 - ANTISCHIUMA IN POWDER - Google Patents

Description

Description of the industrial invention entitled:

ANTIFOAM POWDER

TECHNICAL FIELD

The present description refers to powder defoamers, useful for reducing the formation of foam in a fluid. More precisely, the powder defoamers of the invention comprise a combination of at least one antifoam agent and cob particulate.

STATE OF THE ART

Defoamers are used in various industrial sectors to reduce the amount of foam that forms in the various fluids used in these sectors. These applications include, but are not limited to, waste treatment, water treatment, pulp and paper manufacturing, paper coating, ceramic tile printing, coatings applications, underground operations such as those in mining and oil drilling. , and the like.

Various types of defoamers are currently available. For example, mineral oils, paraffin oils, higher alcohols and their esters, fatty acids, polysiloxanes (silicones) or polysiloxane emulsions have been used as defoamers. Other types of defoamers include hydrophobic silica, tributyl phosphate, ethoxylated fatty alcohols including ethylene oxide and propylene oxide, polypropylene glycol, ethylene oxide and propylene oxide copolymers, and combinations thereof.

In certain embodiments, defoaming agents, usually liquid, have been applied to solid substrates generally selected from materials with a high specific surface such as silica, silica flour, kaolin, clay, diatomaceous earth, alumina, fly ash, finely divided coal , or calcium carbonate. Examples of commercial products suitable as support are SIPERNAT® 22 (Evonik Industries AG) and TIXOSIL® 68 (Rhodia), fine silica powders with high liquid absorption capacity. These products can usually adsorb oil up to 2.5 times their weight.

These defoamers have the appearance of compact or free-flowing powders and can be directly combined with different fluids to reduce the amount of foam that forms in those fluids.

Powder antifoamers are described, for example, in EP 484081 which describes an antifoam ingredient in particulate form comprising, as an antifoam active, a silicone oil absorbed on particles of a solid support. EP 0723795 describes an antifoam in particulate form comprising from 1 to 30 parts by weight of an organic antifoam, from 45 to 99 parts by weight of a zeolite, as a support for the antifoam, and from 1 to 30 parts by weight of a film-forming binder. Furthermore, detergent compositions containing this defoamer are claimed. US 2012/325118 discloses a composition in powder form and free from mineral oils comprising a) at least one fatty acid derivative and / or fatty alcohol derivative, b) at least one silicone oil and c) from 20 to 85% by weight of at least one support material, wherein components a) and b) have been applied to the support material c). The support material c) is selected from the group consisting of gypsum, dolomite, sedimentary limestone and silica.

EP 1060778 discloses a powder defoamer which comprises: (1) 2-30 parts by weight of an antifoam formulation consisting of a water insoluble defoamer oil and a filler; (2) 50-100 parts by weight of support material and (3) 0.1-30 parts by weight of linear and / or branched vinyl polymers containing acidic or neutralized carboxylic groups and higher hydrocarbyl groups.

Although liquid defoamers are used to a greater extent under normal operating conditions, powder defoamers are preferred in many situations due to their ease of handling and storage, particularly in cold and extreme climates such as those found in Alaska, Canada and Russia. Compared to liquid defoamers, powder defoamers have better long-term stability and homogeneity and give the possibility to prepare pre-mixed solid compositions.

There are several disadvantages associated with the use of powder defoamers. For example, powder defoamers are generally not as effective as liquid formulations both in preventing the formation of foam and in dissipating the foam once it has formed. This may be due to a slow release of the antifoam component from the adsorbent material. Other disadvantages include high costs and potential health problems due to the presence of very fine silica particles.

For this reason, there continues to be a need to find powder defoamers that exhibit efficacy and safety comparable to their liquid counterparts.

It has now surprisingly been found that the combination of an antifoam agent and cob particulate as a carrier unexpectedly produces a performance increase over the simple antifoam agent.

Furthermore, the cob particulate is completely natural, biodegradable, renewable, non-toxic and silica-free.

DESCRIPTION OF THE INVENTION

Therefore, the object of the present invention is a powder defoamer comprising:

a) from 25 to 75% by weight, preferably from 35 to 65% by weight, of at least one anti-foaming agent;

b) 75 to 25% by weight, preferably 65 to 35% by weight, of corncob particulate, as a support.

In another embodiment, the present invention relates to a method for reducing foaming in a fluid comprising: I) providing the above described antifoam powder and

II) add said antifoam powder to the fluid.

The characteristics and advantages of the present invention will be immediately apparent to those skilled in the art upon reading the description of the preferred embodiments which follows.

DETAILED DESCRIPTION OF THE INVENTION

The cob is the central core of a corn cob (Zea mays ssp. Mays L.).

The cob if cut transversely consists of three concentric rings. Starting with the inner ring, they are known as the pith, the woody ring and the outer parts (chaff or chaff). All three parts of the cob are absorbent, but the pith and outer parts are more absorbent. The cob particulate is manufactured by drying the cob followed by grinding to produce the particulate which is cleaned by blowing air and separated into various fractions (sizes) by sieving.

Products made with the crown are usually referred to as "griths" and products based on pith and external parts are referred to as "PC" products. Both classes of products or their mixtures can be used for the realization of the present invention, however the absorption (water) for PC products can approach 300% on a weight-to-weight basis, which must be compared with that of the granules equal to about 100 %.

The cob particulate is free flowing and this in combination with its absorbency makes it ideal for use as a "support" for other products.

The suitable cob particulate b) is that in which most of the particles have an average diameter of less than 750 microns and in particular between 50 and 300 microns.

The antifoam agent a) can be any antifoam agent known in the art. In this document, the term "antifoam agent" includes any compound, mixture or formulation that can block the formation of foam or reduce or eliminate the foam previously formed.

In preferred embodiments, the defoamers can be: hydrocarbon materials, silicones, alkylene oxide derivatives, carboxylic acids and their salts, organic esters, bisamides, higher alcohols, trialkyl phosphates, and their mixtures.

For the realization of the present invention hydrocarbon materials are suitable, which are normally liquids (oils) at room temperature (20 ° C), even if solid materials are suitable, for example paraffin waxes which melt temperatures equal to or higher than 50 ° C.

Preferably the liquid hydrocarbons are mineral oils, liquid normal paraffins, liquid isoparaffins and liquid cycloparaffins, containing from 12 to 40 carbon atoms per molecule, naphthenic oils, alpha-olefins, polyalpha-olefins and their mixtures. Among the liquid hydrocarbons, mineral oils are preferred, in particular hydrogenated oils, white mineral oils, or isoparaffinic oils.

Suitable waxes are of mineral origin, especially those derived from petroleum, including microcrystalline waxes and oxidized microcrystalline waxes made from petroleum, paraffin waxes and petroleum jelly, which is a semi-solid hydrocarbon blend. However, synthetic waxes or natural waxes can be used, for example Montana (lignite) waxes, beeswaxes, carnauba waxes or candelilla waxes or mixtures of these waxes can be used.

Examples of suitable alpha-olefins for the preparation of powder defoamer include, but are not limited to, alpha-olefins comprising about 8 to about 36 carbon atoms, more specifically about 12 to about 18 carbon atoms, and even more specifically about 12 to about 14 carbon atoms, and combinations comprising at least one of the aforementioned alphaolefins. Unlike mineral oils, alpha-olefins are biodegradable and environmentally friendly.

Suitable silicone defoamers for the invention include, but are not limited to, polyorganosiloxanes. These antifoam compounds are well known in the art and have been described in numerous patent applications. Examples of suitable polyorganosiloxanes are described in EP 0496510 and are substantially linear polymers of medium formula:

wherein each R can be independently an alkyl or an aryl. Such substituents can be methyl, ethyl, propyl, isobutyl and phenyl. A small amount of chain branches and small amounts of silicon-bonded hydroxyl groups may also be present. Preferred polyorganosiloxanes are polydimethylsiloxanes having terminal blocking units of trimethylsilane and a value of n in the range from 20 to 1500.

Examples of alkylene oxide derivatives are C8-C24alkoxylated alcohols, such as block or random alkoxylated cetyl / stearyl alcohol with from 1 to 100 moles of ethylene oxide and from 1 to 50 moles of propylene oxide, optionally "capped"; polypropylene oxides; polyethylene oxides; polyethylene oxide / polypropylene oxide (EO / PO) block copolymers with number average molecular weight between 1000 and 5000 daltons, in which the copolymer may have a polyoxyethylene terminated polyoxypropylene central chain while in other embodiments, the copolymers may have a central polyoxyethylene chain terminated with polyoxypropylene; organic esters of EO / PO block copolymers, for example dioleate ester of an EO / PO block copolymer; and their mixtures.

Examples of suitable carboxylic acids for use in the practice of the present invention include, but are not limited to, linear or branched C8-C26 unsaturated carboxylic acids, C18-C54 polycarboxylic acids, and combinations thereof. More specific examples include, but are not limited to, oleic acid, eleaidic acid, linoleic acid, linolenic acid, stearic acid, palmitic acid, lauric acid, myristic acid, erucic acid, ricinoleic acid, and combinations thereof. Mixtures of such carboxylic acids obtained from natural oils, for example from tall oil, castor oil, rapeseed oil, soybean oil and sunflower oil, can also be used. It is also recommended, for the realization of the present invention, the use of their salts with multivalent metal cations, such as aluminum or alkaline earth metals, for example aluminum stearate.

In other embodiments, dimer fatty acids or trimer fatty acids can be used.

Suitable esters are reaction products of C8-C26 carboxylic acids, preferably C12-C22 carboxylic acids, with C1-C24 mono- or polyhydric alcohols, preferably with C3-C18 alcohols. The fatty acids which can be used for the preparation of these esters are, for example, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid and cerotic acid. The C1-C24 monohydric alcohols which can be used for esterification of said carboxylic acids are, for example, methanol, ethanol, propanol, butanol, hexanol, dodecanol, stearyl alcohol and behenic alcohol. The dihydric alcohols can be ethylene glycol or propylene glycol; an example of a tri-water alcohol is glycerol; the polyhydric alcohols are, for example, pentaerythritol or sugar alcohols, such as sorbitol and mannitol. The polyhydric alcohols can be partially or completely esterified.

Particularly suitable for the realization of the present invention are the glycerides of the aforementioned fatty acids, for example, triglycerides such as olive oil, castor oil, soybean oil, sunflower oil, avocado oil, corn oil, cotton oil , linseed oil, sesame seed oil, peanut oil, jojoba oil, coconut oil, lard oil, tallow oil and the like, and synthetic mono- and di-glycerides.

Further defoaming agents are polyglycerol esters, such as those prepared by esterification of polyglycerols which contain at least two glycerol units with at least one C8-C26 carboxylic acid.

Suitable bisamides are derived from saturated C8-C26 carboxylic acids, preferably C12-C22 carboxylic acids, and from C2-C7 alkyl diamines. Suitable fatty acids include lauric, myristic, palmitic, stearic and behenic acids and mixtures thereof, such as those derived from natural oils. Suitable diamines are, for example, ethylene diamine, 1,3-propylene diamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, p-phenylene diamine and toluene diamine. Preferred diamines are ethylene diamine and hexamethylene diamine. Specific examples of bisamides are bis-myristoyl-ethylene diamine and bis-palmitoyl-ethylene diamine, bis-stearoyl-ethylene diamine and their mixtures, and the corresponding derivatives of hexamethylene diamine.

Examples of suitable higher alcohols for use in antifoam compositions include but are not limited to linear or branched C8-C48 alcohols, preferably C10-C36 alcohols and more preferably C12-C26 alcohols, and combinations thereof. More specific examples include C12-C26a straight chain fatty alcohols, C12-C26a branched chain fatty alcohols, and combinations thereof. Examples of suitable alcohols are myristic alcohol, cetyl alcohol, stearic alcohol, palmitic alcohol, behenic alcohol and their mixtures.

Advantageously, the defoaming agent of the invention is a by-product with a high boiling point of the purification of alcohols obtained by hydroformylation of alkenes. These products are known commercially as distillation residues of alkenes hydroformylation products (either high-boiling or low-boiling), for example VAMMAR D10 (Exxon) or OXOOEL 9 N (BASF) or ALCHISOR TAL (Sasol).

Examples of trialkyl phosphates include tributumoxyethyl phosphate, triallyl phosphate, tributyl phosphate, tricresyl phosphate, triethyl phosphate, triphenyl phosphate, tris-2-chloroethyl phosphate, cresyl diphenyl phosphate, methyl diphenyl phosphate, tri-dimethylphenyl phosphate, and similar alphosphates.

In a preferred embodiment, the defoamer may comprise one or more hydrophobic solids. Examples of hydrophobic solids include hydrophobic silica, talc, organically modified clay, aluminosilicates, mica, alumina, metal salts of organic acids or mixtures thereof. In preferred embodiments, the defoamer may comprise from about 0.1 to about 40% by weight of hydrophobic solids. Optional hydrophobic solids can improve the performance of the defoamer.

The methodologies for preparing powder defoamers of the present invention are known to a person of ordinary skill in the art. Powder defoamers can be prepared simply by mixing the ingredients, preferably with regular or vigorous agitation, or by spraying the defoamer (s) on the cob particulate, placed in a drum mixer, fluidized bed, etc. If more than one defoamer is present, these can be combined separately or as blends.

These operations can be performed at room temperature or at high temperature, which is particularly useful if you want to evaporate all or part of the solvent, possibly used during the process. In some embodiments, the defoamer may be a solid at room temperature. In this case, it can be melted or dissolved / dispersed in an appropriate solvent, such as water or organic solvent, before being combined with the support. After being thoroughly mixed, the mass can be dehydrated or dried to give a powder.

The powder defoamer described herein can be added to any type of fluid to reduce the amount of foam or suspended gases present in such fluids. Examples of such fluids include, but are not limited to, various underground treatment fluids, e.g. fluids used to drill, complete, work-over, fracture, repair or otherwise; cements or cementitious materials, for example hydraulic cements; compositions for waste water treatment; compositions for water treatment; leaching compositions for mining; compositions for the preparation of cellulose pulp and paper; compositions for separating oil and gas; and compositions for coatings, such as compositions for paper coating and ceramic coating.

The liquid should include an effective amount of powdered defoamer. An "effective amount" of antifoam powder is the amount required to produce the necessary or desired antifoam effect in the fluid in which it is introduced. The effective amount of powder defoamer depends on the particular fluid and can be readily determined by one skilled in the art. Preferably, the powder defoamer is present in an amount of about 0.05 to about 2%, preferably about 0.1 to about 1%, more preferably about 0.1 to about 0.5%, by weight of the fluid, such as a drilling fluid.

Powder defoamer can be added to a fluid before, during, or after mixing the various components of the fluid. The powder defoamer can be added directly as a powder or as an aqueous suspension depending on the intended application.

Examples of industrial applications in which the method of the invention can be applied include, but are not limited to: i) controlling or eliminating foam in various processes associated with pulp and paper processing, such as in the pulping process Kraft, sulphite pulping process, thermomechanical pulping process (TMP), chemical TMP process (CTMP), and the like; ii) prevent inhomogeneities such as craters and rough appearance on the finished product due to trapped air during the production of paints and / or coatings for applications on metals, wood, plastic, concrete, and the like, iii) effectively control the flow properties of the concrete, minimizing the air trapped in the dispersing concrete; iv) increasing the drilling efficiency of oil wells, minimizing the effects of unwanted air; v) controlling the production of foam during the treatment of civil and industrial waste water, and vi) controlling the foam produced during the washing processes and so on. The powder defoamers of the present invention are particularly suitable for use in underground treatment fluids. As used herein, the term "underground treatment" refers to any underground operation that uses a fluid with a desired function and / or for a desired purpose. These underground treatment fluids are used, for example in the drilling, completion and working-over of oil and gas wells and also in stimulation operations (e.g. fracturing).

The following examples are included to show preferred embodiments of the invention.

EXAMPLES

Example 1

Different powder defoamers have been prepared using different solid media and the same defoamer.

The powder defoamers have been prepared by mixing the powder support (60% by weight) and the liquid anti-foaming agent (40% by weight) in a paddle mixer for a few minutes, i.e. a DEFOMEX 2337 mixture (ethylene oxide / oxide propylene copolymer, ester with olein, marketed by Lamberti) at 10% by weight in paraffinic mineral oil. The products obtained were tested following the standard method ASTM E2407-04 (2009) using 0.5 g of powder defoamer.

The foam reduction% was calculated with the following equation:

where is it

ifv = initial foam volume in ml

efv = volume of final foam in ml.

The test was repeated three times for each product and the average foam reduction values (ASTM% fr) are reported in Table 1.

The same powder defoamers were tested in water-based dispersed mud (WBM). The WBM was prepared by adding 24.5 g of API perforation grade bentonite and 0.7 g of sodium carbonate to 350 g of deionized water into a steel cup and mixing with a Hamilton Beach® mixer at low speed for 5 min. 5.25 g of Spersene CF (dispersant marketed by M-I Swaco) was added under stirring and the whole was left under stirring for 5 min. The fluid was then poured into a graduated cylinder and the initial foam volume (ifv) was measured. The WBM was transferred back into the steel cup and 0.5 g of defoamer was added under stirring via a Hamilton Beach® low speed mixer. After 2 minutes the liquid was poured into a graduated cylinder and the final foam volume (efv) was recorded. The foam reduction (WBM% fr) was calculated with the above equation.

The antifoam performance of the liquid agent and of the substrates as such were evaluated following the standard method ASTM E2407-04 using the same amount of substrate or liquid antifoam agent added in the antifoam powder test (0.3 g and 0.2 g respectively ).

All foam reduction values are shown in Table 1.

Table 1

Powder Defoamer Component

Powder support

ASTM% fr ASTM% fr WBM% fr

Silica * <1> 72 <70>

Kaolin * <0> 71 <80>

Talc * <0> 73 <60>

Cob <1> 77 <90>

Beech wood * <0> 74 <85>

Rice husk * <0> 73 <84>

Antifoam agent * <61> - - * Comparative

Example 2

Several powder defoamers have been prepared using corncob flour

and various liquid defoamers (see Table 2). The defoamers are

been prepared by mixing corncob flour (60% by weight of

final product) and liquid antifoam agents (40% by weight) in a

paddle mixer for a few minutes.

Table 2

Antifoam Agent Chemical Nature

Crude soybean oil Triglyceride

SHELLSOL D100 C13- C15 paraffin and naphthenes

DEFOMEX DMA / 108 Ethylene oxide / propylene oxide copolymer,

ester with olein

DEFOMEX 620 Complex blend of various anti-foaming agents

DEFOMEX Polydimethyl siloxane in emulsion

Their performance as an antifoam was evaluated following the

procedure described in ASTM E2407-04. The test was repeated three times for each product and the foam reduction values (ASTM% fr) are reported in Table 3 as average values.

The powder defoamers of Example 2 were tested on a water-based dispersed sludge (WBM) prepared as in Example 1. The foam reduction values (WBM% fr) are reported in Table 3.

The performance of the powder defoamers can be compared with the performance of the original liquid defoamers, shown in Table 3, determined according to ASTM standard method E2407-04 using the same amount of liquid defoamer added in the powder defoamer test (0.2 g ).

Table 3

Agent

Defoamer Defoamer Powder Defoamer

ASTM% fr ASTM% fr WBM% fr

Crude soybean oil 24 32 60

SHELLSOL D100 11 56 90

DEFOMEX DMA / 108 61 64 60

DEFOMEX 620 62 65 70

DEFOMEX 19 22 75

As can be seen from the data reported in Tables 1 and 2, the powder defoamers of the invention have higher antifoam activity than the sum of the activities of the individual components (active solid liquid vehicle) in equal quantities.

Claims (10)

CLAIMS 1) Antifoam powder comprising: a) 25 to 75% by weight of at least one anti-foaming agent; b) 75 to 25% by weight of cob particles. 2) The antifoam powder of claim 1), comprising: a) 35 to 65% by weight of at least one anti-foaming agent; b) 65 to 35% by weight of cob particles. 3) The antifoam powder of claim 1), in which said cob particles have an average diameter of from 50 to 300 microns. 4) The powder defoamer of claim 1), wherein said defoamer is selected from hydrocarbon materials, silicones, derivatives of alkylene oxides, carboxylic acids and their salts, organic esters, bisamides, higher alcohols, trialkyl phosphates and their mixtures . 5) The powder defoamer of claim 4), wherein said defoamer is a hydrocarbon material, selected from mineral oils, normal liquid paraffins, liquid isoparaffins and liquid cycloparaffins, containing from 12 to 40 carbon atoms per molecule, naphthenic oils , alpha-olefins, polyalpha-olefins and their mixtures. 6) The antifoam powder of claim 4), wherein said antifoam agent is a derivative of alkylene oxides, selected from C8-C24 alkoxylated alcohols, polypropylene oxides, polyethylene oxides, polyethylene oxide / polypropylene oxide block copolymers (EO / PO ) with number average molecular weight between 1000 and 5000 daltons, organic esters of EO / PO block copolymers and their mixtures. 7) The antifoam powder of claim 4), in which said antifoam agent is a higher alcohol, selected from the distillation residues of the hydroformylation products of alkenes. 8) Method for reducing the formation of foam in a fluid comprising: I) providing a powder defoamer according to claims 1 to 7 e II) add said antifoam powder to the fluid. 9) The method of claim 8), wherein said powder defoamer is added in an amount comprised between 0.05 and 2% by weight of fluid. 10) The method of claim 8), wherein said fluid is an underground treatment fluid.