Viscosity modifier

Abstract

To provide a viscosity modifier that can impart thixotropy to an aqueous paint, suppress the slippage of a roller and dripping, and obtain a painted surface with excellent appearance. 【Solution means】 A viscosity modifier containing a compound (A) represented by the following general formula (1) and a compound (B) represented by the following general formula (2). TIFF2026122850000011.tif6145(In the formula, R 1 represents a k-valent hydrocarbon group having a biuret bond, R 2 and R 3 are oxyalkylene groups having 2 to 4 carbon atoms, m is a number from 50 to 500, n is a number from 2 to 50, R 4 is a hydrocarbon group having 8 to 24 carbon atoms, and k represents a number of 3 or more.) TIFF2026122850000012.tif7125(In the formula, R 5 and R 6 are oxyalkylene groups having 2 to 4 carbon atoms, p and q are numbers from 2 to 50, R 7 and R 8 represent hydrocarbon groups having 8 to 24 carbon atoms.)

Description

[Technical Field]

[0001] The present invention relates to a viscosity modifier and an aqueous paint composition containing the same. [Background technology]

[0002] For painting the exterior walls of buildings, spray guns and rollers are used. While spray gun painting allows for uniform and efficient application, it presents problems such as paint overspray and odor. Therefore, roller painting, which minimizes these issues, is becoming increasingly popular. However, when painting with a roller, the roller may slide on the surface without rotating, leaving roller marks on the painted surface and resulting in a poor appearance. Water-based paints with added urethane viscosity modifiers (Patent Documents 1-3, etc.) are particularly prone to roller slippage, and uniform application requires skilled workmanship. Furthermore, urethane-based viscosity modifiers cannot impart sufficient thixotropy to water-based paints, causing dripping on vertical surfaces as the paint film dries, degrading its appearance. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-199854 [Patent Document 2] Japanese Patent Publication No. 2000-239649 [Patent Document 3] Japanese Patent Publication No. 2013-122011 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] As described above, when applying water-based paint with a roller, it was difficult to prevent the roller from slipping and the paint from dripping. The object of the present invention is to provide a viscosity modifier that imparts thixotropic properties to an aqueous paint, suppresses the occurrence of roller application marks and dripping, and can obtain a painted surface with excellent appearance.

Means for Solving the Problems

[0005] As a result of intensive research, the present inventors have found that the above problems can be solved by combining specific urethane compounds, and have completed the present invention.

[0006] That is, the present invention relates to the following [1] to [4]. [1] A viscosity modifier containing a compound (A) represented by the following general formula (1) and a compound (B) represented by the following general formula (2).

Chemical formula

Chemical formula

Effects of the Invention

[0007] The viscosity modifier of the present invention can impart thixotropic properties to an aqueous paint, suppress the slipperiness of a roller and the occurrence of dripping, and obtain a painted surface with excellent appearance.

[0008] The viscosity modifier of the present invention contains a compound (A) represented by the following general formula (1) and a compound (B) represented by the following general formula (2).

Chemical formula

Chemical formula

[0009] <Compound (A)> The compound (A) represented by the general formula (1) is, for example, R 1 - (NCO) k (R 1 , k is the same as defined above) a polyisocyanate having a biuret bond, and HO - (R 2 O) m - H (R 2 [[ID=SS]] 3 , m is the same as defined above) a polyether diol represented by, and hexamethylene diisocyanate, and HO - (R 3 O) n - R 4 (R 3, R 4 Polyether monoalcohols represented by (where n is the same as the definition above) It can be obtained by reacting with .

[0010] Polyisocyanates having biuret bonds can be obtained by reacting a polyisocyanate with a so-called biuretizing agent such as water, tert-butanol, or urea, in a molar ratio of isocyanate groups between the biuretizing agent and the polyisocyanate of approximately 1 / 2 to 1 / 100, and then removing the unreacted polyisocyanate and purifying the mixture. As polyisocyanates having biuret bonds, biuret-modified hexamethylene diisocyanate (HDI) is preferred, and among these, those containing a trimer of hexamethylene diisocyanate as the main component are preferred. Examples of commercially available products include "Duranate 24A-100", "Duranate 22A-75P", "Duranate 21S-75E" (all manufactured by Asahi Kasei Corporation), "Desmodul N75", "Desmodul N3200" (manufactured by Bayer AG), "Basonate HB-100" (manufactured by BASF), and "Tronate HDB" (manufactured by Vencorex).

[0011] Polyether diols can be obtained by adding an alkylene oxide with 2 to 4 carbon atoms to a diol compound such as ethylene glycol or propylene glycol. Examples include polyethylene glycol, polypropylene glycol, and polyethylene-polypropylene glycol, but polyethylene glycol is preferred among these. The degree of polymerization of the alkylene oxide, m, is a number between 50 and 500, preferably between 100 and 300. 2 The proportion of ethylene groups in is preferably the total R 2 The amount is 50-100% by mass. The molecular weight is preferably 2,000-30,000, and particularly preferably 4,000-15,000.

[0012] The above formula HO-(R 3 O) n -R 4The polyether monoalcohol represented by is not particularly limited as long as it is an alkylene oxide adduct of a monohydric alcohol. Such compounds can be obtained by addition polymerization of an alkylene oxide such as ethylene oxide, propylene oxide, or butylene oxide to a monohydric alcohol. The degree of polymerization of the alkylene oxide, n, is a number from 2 to 50, preferably from 5 to 30.

[0013] In this specification, "monohydric alcohol" is represented by the following formulas (3), (4), or (5). [ka] [ka] [ka]

[0014] R 4 R is the group obtained by removing the hydroxyl group from the monohydric alcohols of formulas (3) to (5) above. 10 , R 11 , R 12 , R 14 and R 15 These are hydrocarbon groups, such as alkyl groups, alkenyl groups, alkylaryl groups, cycloalkyl groups, and cycloalkenyl groups.

[0015] Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl, pentyl, isopentyl, neopentyl, tertiary pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, isodecyl, undecyl, dodecyl, tridecyl, isotridecyl, myristyl, palmityl, stearyl, isostearyl, eicosyl, docosyl, tetracosyl, triacontyl, 2-octyldodecyl, 2-dodecylhexadecyl, 2-tetradecyloctadecyl, and monomethyl branched-isostearyl groups.

[0016] Examples of alkenyl groups include vinyl, allyl, propenyl, isopropenyl, butenyl, pentenyl, isopentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tetradecenyl, and oleyl groups.

[0017] Examples of alkylaryl groups include phenyl, toluyl, xylyl, coumenyl, mesityl, benzyl, phenethyl, styryl, cinnamyl, benzhydryl, trityl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl, α-naphthyl, and β-naphthyl groups.

[0018] Examples of cycloalkyl and cycloalkenyl groups include cyclopentyl, cyclohexyl, cycloheptyl, methylcyclopentyl, methylcyclohexyl, methylcycloheptyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, methylcyclopentenyl, methylcyclohexenyl, and methylcycloheptenyl groups.

[0019] In equation (4) above, R 13 These are hydrocarbon groups, such as alkylene groups, alkenylene groups, alkylarylene groups, cycloalkylene groups, and cycloalkenylene groups.

[0020] Also, R 4 This is a hydrocarbon group, preferably an alkyl group, and more preferably with a total number of carbon atoms of 8 to 36, and particularly preferably 12 to 24.

[0021] The following describes, but is not limited to, a preferred method for producing compound (A). First, a polyisocyanate having biuret bonds is reacted with a polyetherdiol in an equivalence ratio such that the polyetherdiol is in excess to obtain a reaction intermediate having terminal hydroxyl groups. That is, the reaction between the polyisocyanate and the polyetherdiol is preferably carried out such that the equivalence ratio of the terminal NCO group of the polyisocyanate to the terminal hydroxyl group of the polyetherdiol is preferably 1:1.2 to 8, more preferably 1:1.5 to 5.

[0022] The synthesis of the aforementioned reaction intermediate can be carried out by charging a polyisocyanate having biuret bonds and a polyetherdiol into a reaction apparatus, stirring, and reacting at 60-160°C. A catalyst may be used as needed. Suitable catalysts include amine catalysts such as triethylamine, trimethylamine, dimethylmyristylamine, stearylamine, dimethyldecylamine, N-ethylmorpholine, triethylenetetramine, tolylenediamine, and xylylenediamine, as well as tin catalysts such as monobutyltin oxide, dibutyltin oxide, tetraoctyltin, dioctyltin oxide, dibutyltin dilaurate, and dioctyltin dilaurate. Next, the obtained reaction intermediate is reacted with hexamethylene diisocyanate in an equivalence ratio such that hexamethylene diisocyanate is in excess to obtain a urethane compound with terminal NCO groups, which is then further reacted with a polyether monoalcohol to obtain compound (A).

[0023] <Compound (B)> Compound (B), represented by general formula (2), can be obtained by reacting a hexamethylene diisocyanate with a polyether monoalcohol in an equivalence ratio such that the polyether monoalcohol is in excess. That is, the reaction between the hexamethylene isocyanate and the polyether monoalcohol is preferably carried out such that the equivalence ratio of the terminal NCO group of the hexamethylene isocyanate to the terminal hydroxyl group of the polyether monoalcohol is preferably 1:1.2 to 8, more preferably 1:1.5 to 4. As for the polyether monoalcohol, HO-(R) is used, similar to compound (A).3 O) m -R 4 A polyether monoalcohol represented by [formula] can be used. In addition, in the above reaction, a catalyst that can be used for the synthesis of compound (A) may be used as needed.

[0024] In the viscosity modifier of the present invention, the content ratio of compound (A) and compound (B) is preferably 70 / 30 to 99 / 1, and more preferably 80 / 20 to 95 / 5, in terms of mass ratio, from the viewpoint of suppressing roller slippage and dripping.

[0025] Compounds (A) and (B) constituting the viscosity modifier of the present invention are both solids or viscous substances at room temperature. The viscosity modifier of the present invention is used by adding it to an aqueous solution such as an emulsion and dissolving it. However, since it takes time to dissolve if it remains in its solid or viscous state, it is preferable to dissolve it in a solvent such as water to make it liquid. The amount of solvent is not particularly specified, but it is preferable that the viscosity modifier of the present invention be present in an amount of 10 to 50% by mass, and more preferably 15 to 40% by mass. Examples of usable solvents include aqueous solvents such as water, methanol, ethanol, and propanol, but since volatile solvents may be restricted depending on the application, water is the most preferred among these. In addition, low-volatility alcohols may be added along with water to increase the solubility of the viscosity modifier of the present invention.

[0026] The emulsion resin composition of the present invention is obtained by adding the viscosity modifier of the present invention to an emulsion resin. The amount of additive is not particularly specified, but it is preferably 0.1 to 5% by mass relative to the total amount of the emulsion resin composition, and more preferably 0.2 to 3% by mass. If the amount is less than 0.1% by mass, the effect of the viscosity modifier may not be obtained, and if it exceeds 5% by mass, the effect commensurate with the amount added may not be obtained, or it may not be possible to completely dissolve it in the emulsion resin.

[0027] Any known emulsion resin can be used. Examples of such emulsion resins include urethane emulsions, acrylate emulsions, styrene emulsions, vinyl acetate emulsions, SBR (styrene / butadiene) emulsions, ABS (acrylonitrile / butadiene / styrene) emulsions, BR (butadiene) emulsions, IR (isoprene) emulsions, NBR (acrylonitrile / butadiene) emulsions, or mixtures thereof. Among these emulsion resins, urethane emulsions, acrylate emulsions, and styrene emulsions are preferred due to their particularly good stability.

[0028] The aqueous coating composition of the present invention is obtained by adding the viscosity modifier of the present invention to an emulsion resin-based aqueous coating at an amount of 0.1 to 5% by mass relative to the total amount of the aqueous coating composition, with a preferred amount being 0.2 to 3% by mass. If the amount is less than 0.1% by mass, the viscosity modifier may not be effective, and if it exceeds 5% by mass, the effect commensurate with the amount added may not be obtained, or it may not be possible to completely dissolve it in the aqueous coating.

[0029] Any known emulsion-based water-based paint can be used. As the emulsion resin used in the water-based paint, the emulsion resins listed above can be used, and by adding one or more additives such as pigments, colorants, pearl agents, preservatives, fragrances, plasticizers, defoamers, fillers, antioxidants, UV absorbers, curing agents, catalysts, solvents, flame retardants, antistatic agents, heat stabilizers, pH adjusters, antifreeze agents, wetting agents, pigment dispersants, anti-skinning agents, and drying accelerators to such emulsion resins, an emulsion-based water-based paint can be obtained. [Examples]

[0030] The present invention will be described in detail below with reference to examples. However, the present invention is not limited to these examples.

[0031] Manufacturing Example 1 (Method for producing Compound A-1) 250.0 g of polyethylene glycol (manufactured by Sanyo Chemical Industries, Ltd., product name: PEG-10000, number average molecular weight 11,000) was charged into a 1-liter four-necked flask equipped with a thermometer, nitrogen inlet tube, and stirrer. The mixture was dehydrated at 110°C for 4 hours under reduced pressure of 10 mmHg or less to reduce the water content in the system to 100 ppm. While maintaining the temperature at 110°C, 0.015 g of dibutyltin laurate (manufactured by Tokyo Fine Chemical Co., Ltd., product name: EMBILIZER® L-101) was added, and 1.76 g of biuret isocyanate (manufactured by Asahi Kasei Corporation, product name: Duranate 24A-100) was added. The reaction was carried out for 1 hour with stirring. Next, 5.20 g of hexamethylene diisocyanate (manufactured by Tosoh Corporation, product name HDI) was added, and stirring was continued for 1 hour. Then, 34.5 g of polyoxyethylene alkyl ether (a linear secondary alcohol with 12-14 carbon atoms with 20 moles of ethylene oxide adduct) (manufactured by Nippon Shokubai Co., Ltd., product name: Softanol 200) was added, and the reaction was carried out with stirring for 1 hour. After that, FT-IR was used to confirm that the isocyanate group peak had disappeared, and then 680 g of deionized water was gradually added. The mixture was then aged at 80°C for 1 hour, cooled to 30°C, and 0.5 parts of a preservative (manufactured by Shoei Chemical Co., Ltd.: Levanax BX-150) was added and stirred for 10 minutes to obtain an aqueous solution of compound A-1.

[0032] Manufacturing Example 2 (Method for producing Compound A-2) 250.0 g of polyethylene glycol (manufactured by Sanyo Chemical Industries, Ltd., product name: PEG-6000, number average molecular weight 8,800) was charged into a 1-liter four-necked flask equipped with a thermometer, nitrogen inlet tube, and stirrer. The mixture was dehydrated at 110°C for 4 hours under reduced pressure of 10 mmHg or less to reduce the moisture content of the system to 100 ppm. While maintaining the temperature at 110°C, 0.015 g of dibutyltin laurate (manufactured by Tokyo Fine Chemical Co., Ltd., product name: EMBILIZER® L-101) was added, followed by 2.70 g of biuret isocyanate (manufactured by Asahi Kasei Corporation, product name: Duranate 24A-100), and the reaction was carried out with stirring for 1 hour. Next, 7.60 g of hexamethylene diisocyanate (manufactured by Tosoh Corporation, product name HDI) was added, and stirring was continued for 1 hour. Then, 33.3 g of polyoxyethylene lauryl ether (ethylene oxide 12 molar adduct) (manufactured by Toho Chemical Industry Co., Ltd., product name: Pegnol® L-12S) was added and the reaction was carried out with stirring for 1 hour. After that, FT-IR was used to confirm that the isocyanate group peak had disappeared, and then 685 g of deionized water was gradually added. The mixture was then aged at 80°C for 1 hour, cooled to 30°C, and 0.5 part of a preservative (manufactured by Shoei Chemical Co., Ltd.: Levanax BX-150) was added and stirred for 10 minutes to obtain an aqueous solution of compound A-2.

[0033] Manufacturing Example 3 (Method for producing Compound B-1) In a 1-liter four-necked flask equipped with a thermometer, nitrogen inlet tube, and stirrer, 270.0 g of polyoxyethylene alkyl ether (a linear secondary alcohol with 12-14 carbon atoms with 20 moles of ethylene oxide adduct) (manufactured by Nippon Shokubai Co., Ltd., product name: Softanol 200) was charged and dehydrated at 110°C for 4 hours under reduced pressure of 10 mmHg or less to reduce the water content of the system to 100 ppm. Then, while maintaining the temperature at 110°C, 0.014 g of dibutyltin laurate (manufactured by Tokyo Fine Chemical Co., Ltd., product name: EMBILIZER® L-101) was added, followed by 21.3 g of hexamethylene diisocyanate (manufactured by Tosoh Corporation, product name: HDI), and the reaction was carried out with stirring for 1.5 hours. After confirming that the isocyanate group peak had disappeared by FT-IR, 680.0 g of ion-exchanged water was gradually added. The mixture was then aged at 80°C for 1 hour, cooled to 30°C, and 0.5 parts of a preservative (Levanax BX-150, manufactured by Shoei Chemical Co., Ltd.) were added. The mixture was stirred for 10 minutes to obtain an aqueous solution of compound B-1.

[0034] Manufacturing Example 4 (Method for producing Compound C-1) In a 1-liter four-necked flask equipped with a thermometer, nitrogen inlet tube, and stirrer, 250.0 g of polyethylene glycol (manufactured by Sanyo Chemical Industries, Ltd., product name: PEG-10000, number average molecular weight 11,000) and 45.0 g of polyoxyethylene alkyl ether (a linear secondary alcohol with 12-14 carbon atoms with 20 moles of ethylene oxide adduct) (manufactured by Nippon Shokubai Co., Ltd., product name: Softanol 200) were charged. The mixture was dehydrated at 110°C under reduced pressure of 10 mmHg or less for 4 hours to reduce the moisture content of the system to 100 ppm. Then, while maintaining the temperature at 110°C, 0.015 g of dibutyltin laurate (manufactured by Tokyo Fine Chemical Co., Ltd., product name: EMBILIZER® L-101) and 7.75 g of hexamethylene diisocyanate (manufactured by Tosoh Corporation, product name: HDI) were added and the reaction was carried out with stirring for 1.5 hours. Subsequently, after confirming the disappearance of the isocyanate group peak by FT-IR, 706g of deionized water was gradually added. The mixture was then aged at 80°C for 1 hour, cooled to 30°C, and 0.5 parts of a preservative (Revanax BX-150, manufactured by Shoei Chemical Co., Ltd.) were added. The mixture was stirred for 10 minutes to obtain an aqueous solution of compound C-1.

[0035] The compounds produced in Production Examples 1 to 4 were blended in the proportions shown in Table 1 to prepare the viscosity modifiers for the present invention and comparative examples. Paint samples were prepared by adding 0.4 parts by mass (based on solid content) of these modifiers to 100 parts by mass of test paint, and the thixotropy and roller application properties were evaluated. The results are shown in Table 1. (Composition of the paint used for testing) A test paint was prepared by mixing the following acrylic resin emulsion and other additives. The formulation is as follows: Acrylic emulsion resin: 74.4 parts Ion-exchanged water: 23.3 parts Film-forming aid: 1.9 parts

[0036] (Acrylic resin emulsion) A resin emulsion obtained by emulsion polymerization of a 50% aqueous solution of methyl methacrylate / 2-ethylhexyl acrylate / acrylic acid = 70 / 29 / 1 (mass ratio).

[0037] <Measurement of Thixotropy Index> Measured with a B-type viscometer manufactured by Toki Sangyo Co., Ltd. at 25°C and rotational speeds of 6 rpm and 60 rpm, and the TI value was obtained by dividing the viscosity measured at 6 rpm by the viscosity measured at 60 rpm. The TI value is the ratio of the viscosity values of a paint whose viscosity decreases when the rotational speed of the viscometer is increased tenfold. The closer the TI value is to 1, the more Newtonian the flow becomes, and the larger the TI value, the more structurally viscous the paint becomes.

[0038] <Roller Applicability> The iron plate was installed perpendicular to the floor surface, and the paints obtained in Examples 1 to 5 and Comparative Examples 1 to 4 were applied in a range of 200 × 200 mm using a 4-inch small roller (approximate length 13 mm), and the roller applicability and the appearance of the painted surface were visually judged according to the following criteria. (Judgment Criteria) [[ID="13"]] a) Sagging property ○: Almost no sagging is observed △: Sagging streaks are observed, but they stop within a length of 10 cm ×: Sagging streaks of 10 cm or more occur b) Roller Applicability ○: No roller slippage during application △: Slight roller slippage during application ×: Roller slippage occurs during application

[0039] [Table 1]

[0040] As shown in Table 1, the viscosity modifiers of Examples 1 to 5 impart thixotropic properties to the aqueous paint, suppress roller slippage and sagging, and can obtain a painted surface with excellent appearance. In contrast, none of the viscosity modifiers of Comparative Examples 1 to 4 satisfied all of thixotropic properties, suppression of roller slippage and sagging.

Claims

1. A viscosity modifier containing compound (A) represented by the following general formula (1) and compound (B) represented by the following general formula (2). 【Chemistry 1】 (In the formula, R １ represents a k-valent hydrocarbon group having a biuret bond, R ２ and R ３ R is an oxyalkylene group having 2 to 4 carbon atoms, m is a number from 50 to 500, n is a number from 2 to 50, R ４ (where k represents a hydrocarbon group with 8 to 24 carbon atoms, and k represents a number greater than or equal to 3.) 【Chemistry 2】 (In the formula, R ５ and R ６ R is an oxyalkylene group having 2 to 4 carbon atoms, p and q are numbers from 2 to 50, and R is a number from 2 to 50. ７ and R ８ (This represents a hydrocarbon group with 8 to 24 carbon atoms.)

2. The viscosity modifier according to claim 1, comprising compound (A) and compound (B) in a mass ratio of (A) / (B) = 70 / 30 to 99 / 1.

3. An emulsion resin composition containing 0.1 to 5% by mass of the viscosity modifier described in claim 1 or 2.

4. An aqueous paint composition containing 0.1 to 5% by mass of the viscosity modifier described in claim 1 or 2.

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