This invention relates to defoaming composition and its use, as well as a method for preparing a defoaming composition. The defoaming composition is especially suitable in pulp and paper industry, as well as in any other processing industry when foaming is a significant issue, problem and a hurdle.

Defoamers are widely used in many industries including but not limited to pulp, paper, petroleum, textile and mining industries, water treatment, paints and coatings food and beverage processing, and agriculture.

Defoamers are generally composed of a defoaming agent, such as, but not limited to ethylene bis(stearamides) (EBS) and/or hydrophobic silica, a carrier fluid, and other miscellaneous additives.

Defoamers have primarily two functions, these functions being defoaming and anti- foaming. Knockdown and longevity of defoamers provide important information about the performance of defoamers. Upon formation of foam in a solution the density of the solution decreases. Addition of a defoamer breaks the foam and the density of the solution increases again. The rate of the increase of the density due to the addition of a defoamer indicates how fast the defoamer acts, which is called the knockdown phase. The quicker the knockdown, the more efficient the defoamer is. However, the defoaming effect is temporary and with time the defoamer begins to lose its efficacy and the density starts dropping again as the foam starts to regenerate. The longevity or persistence of a defoamer indicates how long the defoamer works. The longer the longevity or persistence of a defoamer, the more efficient the defoamer is. An ideal defoamer would have fast knockdown and long longevity or will persist over long time i.e. foam would disappear quickly upon addition of the defoamer and it would take long time for the foam to regenerate.

Although commercially available defoamers generally have relatively fast knockdown, they have poor longevity or persistence. Currently available defoamers quickly lose their efficacy and density starts dropping rapidly, which is seen as reappearance of the foam. As it currently stands, in the pulp and paper industry specifically, silicone based defoamers are preferred over other defoamers due to lower dosage requirement and cost-effective performance. However, having said that, silicone based defoamers present themselves with inherent challenges and issues. These challenges, are in part, characterized by environmental and regulatory, carry over/deposit and cost efficiency issues and are further related to complex manufacturing processes. However, in order to increase the longevity of silicone defoamers one would need to use larger amounts of these defoamers in the process. This would in turn result in additional inherent problems due to presence of higher amounts of hydrophobic components, such as silicone compounds, in the process. Hydrophobic components exhibit a tendency to stick on the fiber, and excess amount of hydrophobic components would necessitate additional washing steps later in the process. Therefore, the amount of hydrophobic components in the end fiber needs to be limited and excess amount of silicone defoamers cannot be a reliable solution to limited longevity of the defoamers.

Various industries have long sought for a substitution for silicone-based defoamers, in part, as a potential goal to overcome the challenges experienced thus far with silicone-based defoamers.

Therefore, clearly there is a need to develop novel and efficient defoamers that are first and foremost environmentally friendly, cost effective, simple to make and that are stable but at the same time is characterized by displaying longer longevity along with displaying a fast knockdown phase.

There exists literature concerning hydrophobic deep eutectic solvents, which are solely used for separation and extraction procedures and purposes Florindo et al., ACS Sustainable Chem. Eng. (2018), Vol. 6(3), pp.3888 - 3894 have prepared hydrophobic, low viscous deep eutectic solvents based on fatty acids in order to extract bisphenol A from water. Cao et al., ACS Sustainable Chem. Eng. (2017) Vol. 5(4), pp. 3270 - 3278 have disclosed hydrophobic deep eutectic solvents for extracting Artemisinin from Artemisia annua leaves. Florindo et al., Fluid Phase Equilibria (2017) Vol. 448, pp. 135 - 142 have disclosed use of hydrophobic deep eutectic solvents for extraction of pesticides from aqueous environments. van Osch et al., Green Chemistry (2015), Vol. 17, pp. 4518 - 4521 , disclosed preparing hydrophobic deep eutectic solvents by using decanoic acid and various quaternary ammonium salts for recovering volatile fatty acids from aqueous solutions.

Finally, Ribeiro et al., ACS Sustainable Chem. Eng. (2015), Vol. 3(10), pp. 2469 - 2477 have used hydrophobic eutectic mixtures based on DL-menthol and naturally occurring acids, e.g. pyruvic acid, L-lactic acid, and lauric acid for extracting caffeine, tryptophan, isophthalic acid and vanillin compounds.

Summary of the Invention

One objective of the present invention is to provide solutions to or alleviate the problems encountered in the prior art.

Another objective of the present invention is to provide an effective and environmentally friendly hydrophobic defoamer, which displays long longevity and fast knockdown phase.

These objects are attained with the invention having the characteristics presented below in the characterizing parts of the independent claims. Some preferable embodiments are disclosed in the dependent claims.

The embodiments mentioned in this text relate, where applicable, to all aspects of the invention, namely the defoamer composition, its use as well as to the method of preparing it, even if this is not always separately mentioned. A typical environmentally friendly hydrophobic defoamer composition according to the present invention comprises a deep eutectic solvent comprising a quaternary ammonium salt as a hydrogen bond acceptor (HBA), and a fatty acid with a chain length of more than 14 carbon atoms as a hydrogen bond donor (HBD).

A typical method according to the present invention for preparing an environmentally friendly defoamer composition according to the invention comprises mixing a quaternary ammonium salt as a hydrogen bond acceptor (HBA), and a fatty acid with a chain length of more than 14 carbon atoms as a hydrogen bond donor (HBD) under continuous stirring at an elevated temperature of at least 50 °C.

A typical use according to the present invention of a defoamer composition according to the invention is for decreasing foam formation in manufacture of pulp, paper, board, tissue or the like. Insofar, as is apparent to Applicant’s knowledge, this is the first time that hydrophobic deep eutectic solvents are used for defoaming purposes, especially in manufacture of pulp, paper, board, tissue or the like.

Surprisingly, the current embodiments of the instant invention now propose and set forth the use of a hydrophobic deep eutectic solvent defoamer using a hydrogen bond acceptor (HBA) and a hydrogen bond donor (HBD) and having better defoaming properties as compared to silicone-based defoamers.

Other objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating specific embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Brief Description of the Drawings

The following drawings form a part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of the specification embodiments presented herein.

FIG. 1A shows a Foam and Entrained Air Test (FEAT) graph, density versus time profile at 70°C for the compositions DES-AD, DES-AD1 and DES-AD2 in accordance with some embodiments of the current invention and FIG. 1 B shows the performance of the compositions DES-AD, DES-AD1 and DES-AD2 as measured by Area Under Curve (AUC) at 30 seconds and 3 minutes. FIG. 2A shows a Foam and Entrained Air Test (FEAT) graph, density versus time profile at 60°C for the compositions EST990 (Containing hydrophobic silica defoamer) used as a reference and for DES-AD, DES-AD1 and DES-AD2 in accordance with some embodiments of the current invention and FIG. 2B shows the performance of the compositions EST990, DES-AD, DES-AD1 , DES-AD2 as measured by Area Under Curve (AUC) at 30 seconds and 3 minutes.

FIG. 3A shows a Foam and Entrained Air Test (FEAT) graph, density versus time profile at 50°C for the compositions DES-AD, DES-AD 1 and DES-AD2 in accordance with some embodiments of the current invention and FIG. 3B shows the performance of the compositions DES-AD, DES-AD1 and DES-AD2 as measured by Area Under Curve (AUC) at 30 seconds and 3 minutes.

FIG. 4A shows a Foam and Entrained Air Test (FEAT) graph, density versus time profile at 40°C for the compositions DES-AD, DES-AD 1 and DES-AD2 in accordance with some embodiments of the current invention and FIG. 4B shows the performance of the compositions DES-AD, DES-AD1 and DES-AD2 as measured by Area Under Curve (AUC) at 30 seconds and 3 minutes.

Detailed Description of the Invention

Foaming is a common problem in many industrial processes, especially in pulp washing processes and papermaking operations, where foam can prevent the proper formation of the finished paper and disrupt manufacturing operations. Commercially available defoamers, although generally having fast knockdown, often have, however, a limited longevity or persistence. Once the defoamer loses its efficacy, the density of the medium decreases and foam starts to regenerate. Adding more defoamer is not a solution to increase the defoaming effect, because an excess amount of hydrophobic particles would lead to carryover on the final fiber and require additional washing steps.

It is surprisingly found for the first time in accordance with the various embodiments of the current invention that a composition comprising a hydrophobic deep eutectic solvent, which comprise a quaternary ammonium salt as a hydrogen bond acceptor (HBA) and a fatty acid as a hydrogen bond donor (HBD), performs well as a defoamer, and shows better defoaming performance when compared to commonly used silicone defoamers. Moreover, it is surprisingly found that the chemical defoaming efficacy of the aforementioned defoamer composition according to the present invention is superior compared to conventionally used silicone-based defoamers, which have already been discussed hereinbefore in this disclosure. Further, the defoamer compositions comprising hydrophobic deep eutectic solvent present themselves by being devoid of the significant undeniable challenges equally faced with silicone-formed defoamers. Advantageously, in certain embodiments, a better defoaming performance of the defoamer composition of the present invention compared to a silicone reference, is tested by determining the density as a function of time of a mixture medium including a foaming media, for example white water from a paper mill. To establish better defoaming performance of the composition, the performance may be tested at various temperatures. In some embodiments, the defoaming performance is tested at a temperature of 40°C. In other embodiments, the defoaming performance is tested at a temperature of 50°C. In yet other embodiments, the defoaming performance is tested at a temperature of 60°C. In still other embodiments, the defoaming performance is tested at a temperature of 70°C.

The hydrogen bond acceptor (HBA) may be selected from various quaternary ammonium salts acting as the hydrogen bond acceptor. According to one preferable embodiment the quaternary ammonium salt is selected from alkoxylated quaternary ammonium compounds, such as monoethoxylated ammonium compounds, ethoxylated ammonium compounds or bis(ethoxylated) ammonium compounds, for example ethyl bis(polyethoxyethanol) tallow ammonium ethosulfate. According to one preferable embodiment the quaternary ammonium salt acting as the hydrogen bond donor is ethyl bis-(polyethoxyethanol) tallow ammonium ethosulfate.

According to another embodiment of the present invention the quaternary ammonium salt acting as the hydrogen bond acceptor is selected from quaternary alkyl ammonium halide salts. The quaternary ammonium halide salt may be selected, for example, from quaternary alkyl ammonium chloride, quaternary alkyl ammonium fluoride or quaternary alkyl ammonium bromide. According to one preferable embodiment at least three of the alkyl groups of the quaternary alkyl ammonium halide salt may have a chain length of 4 - 8 carbon atoms. In some advantageous embodiments, the HBA may be selected from the group consisting of, but not limited to, tetrabutylammoniumchloride, tetraheptylammonium chloride, tetraoctylammonium chloride, tetraoctylammonium bromide, methyltrioctyl- ammonium chloride, and methyltrioctylammonium bromide.

According to another embodiment of the present invention the quaternary ammonium salt acting as the hydrogen bond acceptor may be an alkyl dimethyl benzyl ammonium halide salt, preferably C8-C18 alkyl dimethyl benzyl ammonium halide salt, more preferably C12-C18 alkyl dimethyl benzyl ammonium halide salt.

The hydrogen bond donor (HBD) may be chosen from various fatty acids capable of acting as a hydrogen bond donor. The fatty acid may have a chain length of 14 - 24 carbon atoms, preferably 14 - 20 carbon atoms, more preferably 16 - 20 carbon atoms, even more preferably 16 - 18 or 18 - 20 carbon atoms. According to one preferable embodiment of the invention the fatty acid may be tall oil fatty acid. Tall oil fatty acid comprises at least oleic acid and linoleic acid as the major fractions, wherein the amount of saturated and unsaturated C18 fatty acids is >90 weight-%, as well minor fractions of palmitic, stearic, and isostearic acids. According to one preferable embodiment of the invention the defoamer composition is composed of a hydrophobic deep eutectic solvent comprising an ethyl bis- (polyethoxyethanol) tallow ammonium ethosulfate used as a hydrogen bond acceptor (HBA) and a tall oil fatty acid used as a hydrogen bond donor (HBD).

In some advantageous embodiments the defoamer composition is characterized by an HBD/HBA ratio (weight-ratio) ranging from 1 :1 to 8:1 , preferably ranging from 2:1 to 4:1. In some advantageous embodiments the defoamer composition is characterized by an HBD/HBA ratio of 2.2:1. In other advantageous embodiments is characterized by an HBD/HBA ratio of 3.2:1. In still other advantageous embodiments, the composition is characterized by an HBD/HBA ratio of 4.0:1. These HBD/HBA weight ratios are especially preferable when the hydrogen bond donor is tall oil fatty acid and the hydrogen bond acceptor is ethyl bis-(polyethoxyethanol) tallow ammonium ethosulfate.

The defoamer composition preferably comprises less than 10 weight-%, more preferably less than 5 weight-%, even more preferably less than 2.5 weight-%, sometimes even less than 1 weight-%, of water. According to one preferable embodiment the defoamer composition is substantially water-free.

To prepare the defoamer composition, in accordance with some embodiments of the invention, an HBA may be added to an HBD either continuously and/or at certain intervals in order to form a eutectic mixture. The reverse equally holds true, in which case, the HBD may be added to the HBA either continuously and/or at certain intervals. The amount of HBA/HBD added, the time interval, and the time duration of addition depend on factors including but not limited to the compounds being used. The HBA can be added in multiple batches to the HBD. In some embodiments the HBA is added before the HBD. In certain embodiments the HBA is added after the HBD. In other embodiments the HBA and the HBD are added at the same time simultaneously and separately. In yet other embodiments the HBA is added both before and after the HBD. In yet other embodiments the HBA is added before and at the same time as of the HBD. In some embodiments the HBA is added at the same time and after the HBD. According to some embodiments the HBA is added before, after and at the same time as of the HBD.

According to some embodiments of the invention, the defoamer composition is prepared by conducting the reaction by mixing HBA and HBD at an elevated temperature with a reaction time of at least 30 minutes. According to other embodiments of the invention, the reaction is conducted with a reaction time of HBA and HBD of at least 1.5 hours. According to still other embodiments, the reaction is conducted with a reaction time of HBA and HBD of maximum 3 hours. According one embodiment the reaction time may be 30 - 200 min, preferably 60 - 180 min, more preferably 90 - 150 min. The reaction between HBA and HBD is conducted at an elevated temperature. The mixing of the hydrogen bond acceptor (HBA) with the hydrogen bond donor (HBD) may be conducted, for example, at a temperature ranging from 50 - 90 °C, preferably from 70 - 80 °C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is at least 52°C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is at least 54°C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is at least 56°C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is at least 58°C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is at least 60°C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is at least 62°C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is at least 64°C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is at least 66°C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is at least 68°C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is at least 70°C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is at least 72°C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is at least 74°C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is at least 76°C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is at least 78°C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is less than 80°C. According to other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is less than 82°C. According to yet other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is less than 84°C. According to still other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is less than 86°C. According to yet other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is less than 88°C. According to still other embodiments of the invention, the reaction temperature of the mixture of HBA and HBD is less than 90°C.

According to some embodiments of the invention, the reaction temperature of HBA and HBD added separately but simultaneously to form a mixture is at least 50°C. According to one embodiment the invention, the method for preparing an environmentally friendly hydrophobic deep eutectic solvents defoamer composition includes mixing an ethyl bis-(polyethoxyethanol) tallow ammonium ethosulfate used as a hydrogen bond acceptor (HBA) with a tall oil fatty acid used as a hydrogen bond donor (HBD) under continuous stirring at an elevated temperature. In some advantageous embodiments, the mixing of the ethyl bis-(polyethoxyethanol) tallow ammonium ethosulfate used as the hydrogen bond acceptor (HBA) with the tall oil fatty acid used as the hydrogen bond donor (HBD), is reacted at a temperature ranging from 50°C to 90°C for 30 - 180 minutes, and more preferably from 70°C to 80°C for 60 - 120 minutes, under continuous stirring.

According to advantageous embodiments, one of the main target liquids to treat and thereby defoam, is an industrial process liquid, slurry or suspension, preferably a liquid, slurry or suspension derived from the pulp and paper industry. According to one embodiment of the invention, an environmentally friendly defoamer composition product is used in the pulp and paper industry for decreasing foaming formation.

According to one embodiment of the invention, method for controlling foam in papermaking process comprises adding to a pulp slurry and/or suspension the defoamer composition disclosed herein.

According to one embodiment of the invention the defoamer composition may be added to a liquid medium in amount of 10 - 50 ppm, preferably 15 - 45 ppm, more preferably 20 - 30 ppm, especially in processes related to manufacture of pulp or paper.

The defoamer composition can be added to a liquid, slurry or suspension to be treated continuously and/or at certain intervals. Amounts of the defoamer composition added, time interval, and time duration of addition depend on, factors including but not limited to, amount of the liquid, slurry or suspension to be treated; properties and components of the liquid, slurry or suspension; amount of foam; foaming susceptibility of the liquid, slurry or suspension and on the process itself. In certain embodiments the liquid is an industrial process liquid, slurry or suspension. The composition and methods of the present invention can in reality be practiced in any industrial process, in which foaming is a concern, including but not limited to process streams commonly encountered when processing or manufacturing wood pulp, paper, textiles, cement or paint. In addition, the present invention is suitable for processes for treating industrial wastewater, food processing, and oil drilling. The composition and methods of the present invention can be used practically with any industrial water system where foaming is a problem, but are particularly well-adapted, but not limited to, to recirculating water systems as found in papermaking systems, cooling water systems (including cooling towers, open and closed loop cooling units), industrial raw water systems, drinking water distribution systems, sanitizing drinking water system, oil production or recovery systems (oil field water system, drilling fluids), fuel storage system, metal working systems, heat exchangers, reactors, equipment used for storing and handling liquids, boilers and related steam generating units, radiators, flash evaporating units, refrigeration units, reverse osmosis equipment, gas scrubbing units, blast furnaces, sugar evaporating units, steam power plants, geothermal units, nuclear cooling units, water treatment units, pool recirculating units, mining circuits, closed loop heating units, machining fluids used in operations such as for example drilling, boring, milling, reaming, drawing, broaching, turning, cutting, sewing, grinding, thread cutting, shaping, spinning and rolling, hydraulic fluids, cooling fluids, and the like. In some embodiments, the industrial process stream is an industrial process stream in a cement-making process or a paint-making process.

Definitions

As used herein, the term“solvent”, refers to a substance that dissolves a solute, e.g. chemically distinct liquid, solid or gas, thereby resulting in a solution. A solvent is usually a liquid but can equally also be a solid, a gas, or a supercritical fluid. The quantity of solute that can dissolve in a specific volume of solvent varies with temperature.

As used herein, the term“deep eutectic solvent” denotes a liquid, which is a mixture of two or more individual components, which has a melting point below the melting points of the individual pure components. A deep eutectic solvent is usually prepared by mixing the individual components under elevated temperature, which leads to self-association of the components probably through hydrogen bond interactions. Usually deep eutectic solvents have melting point <100 °C, and preferably they are in liquid form at temperature 20 - 40 °C.

All ratios herein in this disclosure are meant to reflect weight-ratios, unless explicitly stated otherwise.

For the purpose of the current application, the term“defoamer” denotes a chemical that breaks foam after it has been formed and/or prevents foam formation, also otherwise known as anti-foam agents and/or remove air bubbles from a liquid and helps them to rise to the surface, also otherwise known as air release agents. Defoamer composition of the present invention prevents, controls and/or reduces foaming. Prevention of foaming means not letting the foam being formed, control of foaming means limiting amount of foam to certain extent or amount depending on the process, reduction of foaming means decrease of amount of foam. Defoamer composition of the present invention is to be used to treat aqueous liquids susceptible to foaming and/or foam containing aqueous liquids. Treating the liquid with the defoamer composition is achieved by adding the defoamer composition to the liquid or vice versa. Components of the defoamer composition of the current invention show synergistic behavior, thus the defoaming efficiency of the composition is much higher than that of the individual components.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All technical and scientific terms used herein have the same meaning. Although any materials similar or equivalent to those described herein can also be used in the practice of the present invention, exemplary materials are described for illustrative purposes.

As used herein and in the appended claims, the singular form“a,”“and,”“the” include plural referents unless the context clearly dictates otherwise.

It should be understood that operations, and in particular, the method steps may be shown and described as being in a sequence or temporal order, but they are not necessary limited to being carried out exactly as claimed and can therefore be carried out in any particular sequence or order.

The terms “comprises,” “comprising,” “includes,” “including,” “having” and their conjugates mean“including but not limited to.” Terms and phrases used in this application, and variations thereof, unless otherwise expressly stated, should be construed as open ended as opposed to limiting. As examples of the foregoing, the term“including” should be read as meaning“including, without limitation” or the like. The term“example” is used to provide exemplary instances of the item in discussion, not an exhaustive or limiting list thereof. Adjectives such as e.g.,“conventional,” “traditional,”“known” and terms of similar meaning should not be construed as limiting the item described to a given time period, or to an item available as of a given time. But instead these terms should be read to encompass conventional, traditional, normal, or standard technologies that may be available, known now, or at any time in the future.

Likewise, a group of items linked with the conjunction“and” should not be read as requiring that each and every one of those items be present in the grouping, but rather should be read as“and/or” unless expressly stated otherwise. Similarly, a group of items linked with the conjunction“or” should not be read as requiring mutual exclusivity among that group, but rather should also be read as“and/or” unless expressly stated otherwise. The presence of broadening words and phrases such as“one or more,”“at least,”“but not limited to,” or other like phrases in some instances shall not be read to mean that the narrower case is intended or required in instances, wherein such broadening phrases may be absent.

It will be readily understood by one of ordinary skill in the relevant art that the present invention has broad utility and application. Although the present invention has been described and illustrated herein with referred to certain embodiments, it will be apparent to those of ordinary skill in the art that other embodiments may perform similar functions and/or achieve like results, and that the described embodiments are for illustrative purposes only. Thus, it should be understood that various features and aspects of the disclosed of the disclosed embodiments can be combined with, or substituted for one another in order to form varying modes of the disclosed invention. Many different embodiments such as variations, adaptations, modifications, and equivalent arrangements are will be implicitly and explicitly disclosed by the embodiments described herein, and thus fall within the scope and spirit of the present invention.

Further, the discussed prior art is not an admission by Applicant and should not be construed that the current invention does not antecede and is not patentable over the discussed prior art, but has merely been presented to better define the knowledge in the field to a skilled artisan and to the reader in general.

Thus, the scope of the embodiments of the present invention should be determined by the appended claims and their legal equivalents. The examples below are illustrative.

Examples

The following examples as well as the Figures are included to demonstrate the various embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the Examples and Figures represent techniques discovered by the inventors to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. Flowever, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention.

Foam and Entrained Air Tests (FEAT) were performed to test the defoaming efficiency of compositions in accordance with embodiments of the present invention. FEAT test employs a testing apparatus, which used to determine the efficacy of defoamer compositions in a laboratory setting. The apparatus measures the change in the density as a function of time of the filtrate as the defoamer composition is introduced. The measure of the change in density of a filtrate is a direct measurement of the change in entrained air. In pulp and paper mills, for example, presence of entrained air can disturb sheet formation and drainage.

The experimental set up contains a water bath, temperature control, a foam column, a micropump, a density meter, a computer, and acquisition software. Testing of the samples utilizes a recirculatory foam column attached to a pump. The hose leading from the pump is connected to a density meter, which is connected back to the top of the foam column. The foaming medium is added to the test unit and pumped through the unit to fill the lines. Once the pump is turned on and the density drops due to air entrainment, a defoamer composition is added. The test is run for a predetermined time and adequate number of data points are collected by the data acquisition software. A line graph is generated to show the change in density of the liquor of the time period. The area under the curve for each test is then calculated. Those samples having the highest area under the curve measurements are those samples that performed the best.

For each of the Examples, white water was used as the foaming medium. 400 ml_ of the foaming medium was heated to 70° C, 60° C, 50° C or 40° C and circulated. As the foaming medium was circulated, the density of the medium dropped due to formation of foams. The defoaming property of the defoamer compositions was tested at four different temperatures at 70° C, 60° C, 50° C and 40° C.

Three defoamer compositions were tested. Following abbreviations have been used in the Examples:

DES-AD: ethyl bis-(polyethoxyethanol) tallow ammonium ethosulfate (FIBA), tall oil fatty acid (HBD); FIBD:FIBA weight ratio 2.2:1

DES-AD1 : ethyl bis-(polyethoxyethanol) tallow ammonium ethosulfate (HBA), tall oil fatty acid (HBD); HBD:HBA weight ratio 3.2:1

DES-AD2: ethyl bis-(polyethoxyethanol) tallow ammonium ethosulfate (HBA), tall oil fatty acid (HBD); HBD:HBA weigh ratio 4.0:1

Example 1 : Efficacy of DES-AD, DES-AD1 and DES-AD2 defoamer compositions at 70°C

Example 1 shows good efficacy of DES-AD, DES-AD1 and DES-AD2 defoamer compositions at 70°C, especially of DES-AD defoamed composition.

10 pl_ DES-AD, DES-AD1 and DES-AD2 defoamer was added to the defoaming medium when the medium density reached a desired minimum point. As seen in FIG. 1 A the density, i.e. knockdown phase, increased rapidly to a maximum density of approximately 0.915 g/cm ³ for DES-AD, to a maximum density of approximately 0.91 g/cm ³ for DES-AD1 and to a maximum density of approximately 0.905 g/cm ³ for DES-AD2 within 50 seconds. Thereafter, the density then dropped to 0.885 g/cm ³ . As can be seen in FIG. 1 A, the higher amount of ethyl bis-(polyethoxyethanol) tallow ammonium ethosulfate in the defoamer composition, the greater efficacy of increasing the density and the increased longevity of efficacy. In other words, DES- AD, which had the highest amount of ethyl bis-(polyethoxyethanol) tallow ammonium ethosulfate exhibited the greatest effect at defoaming (i.e. higher density) and increasing the longevity (i.e. increased time at a given specific density) of defoaming compared to DES-AD1 and DES-AD2. The performance as measured by Area Under Curve (AUC) confirmed these findings, where DES-AD displayed the highest performance compared to DES-AD1 and DES-AD2 as displayed in FIG. 1 B after 30 seconds and 3 minutes.

Example 2: Efficacy of DES-AD, DES-AD1 and DES-AD2 defoamer compositions at 60°C

Example 2 shows an increased efficacy of DES-AD, DES-AD1 and DES-AD2 defoamer compositions at 60 °C compared to the reference silicone defoamer EST990. 10-pL DES-AD, DES-AD1 , DES-AD2 defoamer and a reference silicone defoamer

EST990 was added to the medium when the medium density reached a desired minimum point. As seen in FIG. 2A the density, i.e. knockdown phase, increased rapidly to a maximum density of approximately 0.930 g/cm ³ for DES-AD, to a maximum density of approximately 0.920 g/cm ³ for DES-AD1 and to a maximum density of approximately 0.912 g/cm ³ for DES-AD2 within 50 seconds and approximately 0.922 g/cm ³ for EST990 within 30 seconds. Thereafter, the density then dropped to 0.890 g/cm ³ . As can be seen in FIG. 2A, the compositions DES- AD, DES-AD1 , DES-AD2 are at least as efficient or better at defoaming the medium compared to the reference silicone defoamer EST990, as the graphs of DES-AD, DES-AD1 , DES-AD2 are at least at the same level or above the EST990 graph. Using a temperature of 60°C compared to 70°C (Example 1 ) likewise extends the longevity (i.e. increased time at a given specific density) of defoaming capacity of DES-AD1 and DES-AD2. Also, these results are confirmed by determining the Area Under Curve (AUC) as depicted in FIG. 2B, where the performance was increased both after measurement at 30 seconds and 3 minutes at 60°C FIG. 2B compared to 70°C FIG. 1 B. Example 3: Efficacy of DES-AD, DES-AD1 and DES-AD2 defoamer compositions at 50 °C and 40°C

Example 3 shows that decreasing the temperature to 50°C or 40°C does not further increase the defoaming efficacy of DES-AD, DES-AD1 and DES-AD2 defoamer compositions.

10-pL DES-AD, DES-AD1 , DES-AD2 defoamer was added to the medium when the medium density reached a desired minimum point and the effect on the density was tested at 50°C (FIG. 3A) and at 40°C (FIG. 4A). As seen previously the density, i.e. knockdown phase, increased rapidly to a maximum density of approximately 0.915 g/cm ³ for DES-AD, to a maximum density of approximately of approximately 0.91 g/cm ³ for DES-AD1 and to a maximum density of approximately 0.905 g/cm ³ for DES-AD2 within 50 seconds. But it is seen the defoaming longevity capacity is decreased at 50°C and at 40°C compared to at 60°C and at 70°C, as all the graphs are less extended horizontally in FIG. 3A and FIG. 4A compared to FIG. 1A and FIG. 2A. These results were confirmed by determining the Area Under Curve (AUC) as depicted in FIG. 3B at 50°C and FIG. 4B at 40°C, where the performance was decreased compared to results shown in FIG. 2B and FIG. 1 B.