Oil-in-water emulsion defoamer

Abstract

To provide a higher-alcohol emulsion antifoamer that exhibits high defoaming performance even at a high temperature of about 60°C, and sustains the defoaming performance for a long time.SOLUTION: An oil-in-water emulsion antifoamer contains an oil phase component containing a C12-30 alcohol (A), and a polycarboxylic acid polymer having a constitutional unit derived from an unsaturated dicarboxylic acid (B).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an oil-in-water emulsion defoaming agent, more specifically to an oil-in-water emulsion defoaming agent which has improved defoaming performance at high temperatures and which maintains its defoaming effect for a longer period of time than conventional products. [Background technology]

[0002] Higher alcohol-based oil-in-water emulsion defoamers have been widely used in papermaking processes due to their excellent characteristics, such as a good defoaming effect on microbubbles present in pulp slurry and almost no effect on the sizing effect (see Patent Documents 1 to 4). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-113104 A [Patent Document 2] JP 2015-54259 A [Patent Document 3] Patent No. 3690773 [Patent Document 4] Patent No. 3964965 Summary of the Invention [Problem to be solved by the invention]

[0004] For defoamers containing higher alcohols as the main component, it is desirable to have high temperature suitability, so that they can exhibit good defoaming performance even at high temperatures of 60°C or higher. However, conventional defoamers do not have sufficient performance, and it is necessary to add a large amount of the defoamer. In addition, there is a problem that the defoaming performance does not last in systems that contain a lot of black liquor-derived components or in papermaking processes with a high water circulation rate. The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a higher alcohol-based emulsion-type defoaming agent which exhibits good defoaming performance even at a high temperature of about 60°C and is excellent in defoaming durability. [Means for solving the problem]

[0005] The present invention is as follows. [1] An oil phase component (A) containing an alcohol having 12 to 30 carbon atoms; A polycarboxylic acid polymer (B) having a structural unit derived from an unsaturated dicarboxylic acid; An oil-in-water emulsion defoamer containing [2] The oil-in-water emulsion defoaming agent according to [1], wherein the polycarboxylic acid polymer (B) is polymaleic acid, an acrylic acid-maleic acid copolymer, or a salt thereof. [3] The oil-in-water emulsion defoaming agent according to [1] or [2], wherein the polycarboxylic acid polymer (B) is contained in an amount of 1 to 30 parts by mass per 100 parts by mass of the oil phase component (A). [4] The oil-in-water emulsion defoaming agent according to any one of [1] to [3], wherein the oil phase component (A) further contains a hydrocarbon wax. Effect of the Invention

[0006] The oil-in-water emulsion defoaming agent of the present invention exhibits good defoaming performance even at high temperatures of about 60° C., and is excellent in defoaming durability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] The oil-in-water emulsion type defoaming agent of the present invention contains an oil phase component (A) containing an alcohol having 12 to 30 carbon atoms, and a polycarboxylic acid polymer (B) having a structural unit derived from an unsaturated dicarboxylic acid. Each component will be described in detail below.

[0008] (Alcohols with 12 to 30 carbon atoms) In the present invention, one or more natural alcohols and / or synthetic alcohols can be used as the alcohol having 12 to 30 carbon atoms. Examples of natural alcohols include saturated alcohols such as lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, eicosanol, docosanol, tetracosanol, hexacosanol, octacosanol, and triacontyl alcohol, and unsaturated alcohols such as oleyl alcohol. Examples of synthetic alcohols include linear, unbranched saturated alcohols synthesized by the Ziegler method, linear primary alcohols or branched primary alcohols synthesized by the Oxo method, or mixtures of these alcohols with different carbon numbers, and linear secondary alcohols produced by air oxidation of paraffin. The amount of the alcohol having 12 to 30 carbon atoms is not particularly limited, but may be 20 to 80% by mass based on the total amount of the oil phase component (A), and is preferably about 40 to 60% by mass in terms of the antifoaming effect.

[0009] (Hydrocarbon wax) The oil-in-water emulsion defoaming agent of the present invention may further contain, as the oil phase component (A), a hydrocarbon wax such as paraffin wax, polyethylene wax, α-olefin wax, microstearate wax, petrolatum, etc. Among these, α-olefin wax having a melting point of 70° C. or higher is preferred from the viewpoint of high temperature suitability. The α-olefin wax is preferably an α-olefin having 26 or more carbon atoms, and specific examples thereof include 1-hexacosene, 1-octacosene, 1-triacontene, dodoriacontene, 1-tetratriacontene, 1-hexatriacontene, 1-octatriacontene, and 1-tetracontene. The amount of the hydrocarbon wax to be added is not particularly limited, but may be 20 to 80% by mass based on the total amount of the oil phase components, and is preferably about 40 to 60% by mass in terms of the defoaming effect.

[0010] (Other oil phase components) The oil-in-water emulsion defoaming agent of the present invention can further contain one or more of liquid fats and oils, solid fats and oils, waxes, mineral oils, higher fatty acids, fatty acid amides derived from higher fatty acids, ester oils, silicone oils, polyoxyalkylene oxides, and the like, as required.

[0011] The defoaming agent according to the present invention is an oil-in-water emulsion in which the oil phase component (A) containing the above-mentioned components is emulsified and dispersed in an aqueous medium. The mixing ratio of the oil phase and the aqueous phase is not particularly limited as long as an oil-in-water emulsion can be obtained, but the oil phase is generally about 5 to 40 mass% of the total amount of the defoaming agent.

[0012] (Polycarboxylic acid polymer (B)) The polycarboxylic acid polymer (B) used in the present invention has a structural unit derived from an unsaturated dicarboxylic acid, such as maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, citraconic acid, or citraconic anhydride. The weight average molecular weight of the polycarboxylic acid polymer (B) is usually from 1,000 to 100,000, preferably from 1,500 to 50,000, and more preferably from 2,000 to 30,000.

[0013] The polycarboxylic acid polymer (B) used in the present invention may be a homopolymer of an unsaturated dicarboxylic acid or a copolymer of an unsaturated dicarboxylic acid and another monomer copolymerizable therewith, but among them, a copolymer of an unsaturated dicarboxylic acid and an unsaturated monocarboxylic acid is preferred. Examples of the unsaturated monocarboxylic acid include acrylic acid, methacrylic acid, and crotonic acid. The molar ratio of the structural unit (I) derived from an unsaturated dicarboxylic acid to the structural unit (II) derived from an unsaturated monocarboxylic acid is preferably (I) / (II)=20 / 80 to 80 / 20, more preferably (I) / (II)=30 / 70 to 70 / 30. Specific examples of the polycarboxylic acid polymer (B) include polymaleic acid, acrylic acid-maleic acid copolymer, acrylic acid-maleic anhydride copolymer, olefin-maleic acid copolymer, maleic anhydride-ethylene copolymer, and maleic anhydride-styrene copolymer.

[0014] The polycarboxylic acid polymer (B) may be a salt neutralized with an alkaline substance, for example, an alkali metal salt such as sodium or potassium, an alkaline earth metal salt such as calcium or magnesium, an ammonium salt, or an organic amine salt such as monoethanolamine or triethanolamine.

[0015] In the present invention, the amount of the polycarboxylic acid polymer (B) to be blended is not particularly limited, but it can be blended in a ratio of preferably 1 to 30 parts by mass, more preferably 3 to 20 parts by mass, and even more preferably 5 to 10 parts by mass, per 100 parts by mass of the oil phase component (A).

[0016] In producing the oil-in-water emulsion defoaming agent of the present invention, a known nonionic surfactant or anionic surfactant can be used as an emulsifier.

[0017] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, fatty acid esters of polyoxyethylene sorbitan, fatty acid esters of polyoxyethylene glycerin, polyoxyethylene alkylphenol ethers, polyoxyethylene polyoxypropylene alkyl ethers, fatty acid esters of sorbitan, and fatty acid esters of glycerin.

[0018] Examples of anionic surfactants include sulfate salts of polyoxyethylene alkyl ethers, phosphate salts of polyoxyethylene alkyl ethers, phosphate salts of polyoxyethylene alkylphenol ethers, maleic acid half ester salts of polyoxyethylene alkyl ethers, maleic acid half ester salts of polyoxyethylene alkyl phenol ethers, alkylbenzenesulfonates, alkyl sulfate salts, and alkylnaphthalenesulfonates.

[0019] The oil-in-water emulsion defoamer of the present invention can be obtained by a known emulsification method. For example, an oil phase component and an emulsifier are charged in a vessel, heated to above the melting point of the oil phase, mixed, and then hot water is added and mixed at high speed to emulsify, but the production method is not particularly limited. Also, emulsifiers such as homomixers, high-pressure emulsifiers, and colloid mills may be used as emulsification equipment. The polycarboxylic acid polymer (B) may be added at any stage of emulsification, but it is preferable to add it after emulsification from the viewpoint of ease of adjusting the emulsified state.

[0020] The oil-in-water emulsion defoaming agent of the present invention can use a thickener for the purpose of preventing separation of the emulsion. Examples of the thickener include water-soluble polymers such as starch, cellulose, pullulan, sodium alginate, gum arabic, guar gum, glucomannan, xanthan gum, welan gum, diutan gum, rhamsan gum, tragacanth gum, locust bean gum, agarose, glycogen, methylcellulose, ethylcellulose, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxyethylmethylcellulose, carboxymethylethylcellulose, cellulose acetate phthalate, polyvinyl alcohol, polyethylene oxide, polyacrylamide, polymethacrylamide, polyacrylic acid, polymethacrylic acid, copolymers of acrylamide and acrylic acid, copolymers of acrylamide and methacrylic acid, copolymers of methacrylamide and acrylamide, and copolymers of methacrylamide and methacrylic acid. Furthermore, if necessary, a viscosity stabilizer, a preservative, an antifungal agent, a bactericide, an antirust agent, an antiskinning agent, etc. may be contained.

[0021] The oil-in-water emulsion defoaming agent of the present invention can be applied to foamable liquids containing water, and can be suitably used in particular as a defoaming agent for the paper and pulp industry, food industry, textile industry, paint industry, chemical industry, and wastewater treatment processes.

[0022] The amount of the oil-in-water emulsion defoaming agent of the present invention to be added varies depending on the state of the target system and the degree of need for defoaming, but generally, the amount is 1 to 100 ppm relative to the foaming liquid. The defoaming agent may be added directly to the foaming liquid or may be added in a process prior to the location where foaming occurs. EXAMPLES

[0023] The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. In the examples, % means % by mass, and parts means parts by mass, unless otherwise specified.

[0024] <Antifoaming agent manufacturing example> 7.0 parts of higher alcohol, 7.0 parts of hydrocarbon wax, and 0.5 parts of emulsifier shown in Table 1 were charged in a flask, and the temperature was raised to 85-95°C, and then 15 parts of hot water at the same temperature was added and stirred to obtain an oil-in-water emulsion. The mixture was then passed through a Dispermill, mixed with an aqueous solution containing a thickener, and cooled after addition of a polycarboxylic acid polymer to obtain an oil-in-water emulsion defoamer. The amount of each component in Table 1 is expressed as mass% relative to the total amount (100 mass%) of all components.

[0025] <How to prepare the test solution> Black liquor obtained from a paper mill was diluted with tap water to a volatile residue concentration of 0.2% to prepare the test liquid.

[0026] <Performance evaluation of defoamers> 1000 ml of the test liquid prepared by the method described below is placed in a glass cylinder with an inner diameter of 80 mm and a height of 540 mm and kept at 60°C. Next, a water pump is used to circulate the liquid from the bottom to the top of the cylinder at a flow rate of 16 L / min to cause foaming. After a certain amount of foaming is achieved, an antifoaming agent is added (4 μL for the examples and comparative examples. Among the comparative examples, only the conventional product is added at 8 μL). After that, the minimum foam height (mm) is measured, and the foam height after 5 minutes of circulation is measured.

[0027] [Table 1]

[0028] [Table 2]

[0029] From the results of the defoaming test in Table 2, it is seen that the higher alcohol-based emulsion type defoaming agent of the present invention exhibits good defoaming performance even at high temperatures, and is excellent in defoaming durability, compared with the conventional products and the comparative examples, and is therefore very useful in practical use.

Claims

1. An oil phase component (A) containing an alcohol having 12 to 30 carbon atoms; a polycarboxylic acid-based polymer (B) which is a homopolymer of an unsaturated dicarboxylic acid or a copolymer of an unsaturated dicarboxylic acid and an unsaturated monocarboxylic acid, in which the molar ratio of a structural unit (I) derived from an unsaturated dicarboxylic acid to a structural unit (II) derived from an unsaturated monocarboxylic acid is (I) / (II)=20 / 80 to 80 / 20; An oil-in-water emulsion defoamer containing

2. 2. The oil-in-water emulsion defoaming agent according to claim 1, wherein the polycarboxylic acid polymer (B) is polymaleic acid, an acrylic acid-maleic acid copolymer, or a salt thereof.

3. 3. The oil-in-water emulsion defoaming agent according to claim 1, wherein the polycarboxylic acid polymer (B) is contained in an amount of 1 to 30 parts by mass per 100 parts by mass of the oil phase component (A).

4. The oil-in-water emulsion defoaming agent according to any one of claims 1 to 3, wherein the oil phase component (A) further comprises a hydrocarbon wax.

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