Epoxy resin color paste as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of color paste, and particularly relates to epoxy resin color paste as well as a preparation method and application thereof. The epoxy resin color paste comprises resin, an acrylic acid copolymerization modified polyurethane dispersant, an unsaturated carboxylic acid dispersant and a pigment, the acrylic acid copolymerization modified polyurethane dispersing agent is obtained by modifying polyurethane by adopting an acrylic acid-styrene-butyl acrylate terpolymer. The acrylic acid copolymerization modified polyurethane dispersant and the unsaturated carboxylic acid dispersant of specific types are adopted and have a synergistic effect, and through the combined action of chemical modification of the acrylic acid copolymerization modified polyurethane dispersant and physical modification of physical mixing of the two different types of dispersants, the water resistance of the coating is improved; the pigment is fully dispersed in the epoxy resin color paste, the epoxy resin color paste is fully dispersed in the colored paint, the storage stability of the color paste and the colored paint can be considered, and a colored paint film is not prone to flooding and floating.

Description

Technical Field

[0001] The invention belongs to the technical field of color pastes, and in particular relates to an epoxy resin color paste and a preparation method and application thereof. Background Art

[0002] Epoxy floor paint is often used in places requiring clean floors, such as dust-free workshops and sports venues. Epoxy floor paint has stringent requirements for wear and corrosion resistance. Directly adding pigments as colorants to epoxy floor paints can lead to serious dust pollution and inconvenient metering. Stably dispersing pigment particles in a liquid carrier to form a pigment paste not only avoids these drawbacks, but also reduces the particle size distribution, improves tinting strength, and reduces pigment usage. This has become the primary colorant used in the coatings industry in recent years.

[0003] Epoxy colorants are commonly used in epoxy floor coatings. The raw materials for epoxy colorants primarily include epoxy resin, weather-resistant pigments, dispersants, and solvents. The grinding process for epoxy colorants involves pre-dispersion followed by refining to the micron level using a three-roll mill, sand mill, or basket grinder. Currently, the core technical challenges of epoxy colorants lie in poor pigment dispersion stability, such as sedimentation and flocculation; low grinding efficiency, resulting in high energy consumption and equipment wear; compatibility issues with the curing system, which in turn affects coating performance; and significant environmental pressures, including high VOC emissions, due to the presence of benzene-based solvents and the potential presence of heavy metals in the pigments.

[0004] Some studies have used coupling agents to modify the surface of pigments, improving their dispersibility and, consequently, the storage stability of color pastes. However, because the same silane coupling agent has specific adaptability to different fillers and resins, improper selection can not only affect material performance but also lead to resource waste. Silane coupling agents are also sensitive to air and moisture, prone to decomposition and inactivation, placing high demands on both production and storage.

[0005] Therefore, there is an urgent need to provide a color paste that has good storage stability and is green and environmentally friendly; the prepared epoxy floor coating has good storage stability and is not prone to floating color and blooming. Summary of the Invention

[0006] The present invention aims to address one or more technical problems existing in the aforementioned prior art and to provide at least a beneficial alternative. Specifically, the present invention provides an epoxy resin color paste having good storage stability and being environmentally friendly; the epoxy floor coating prepared therefrom has good storage stability and is not susceptible to color floating or floating.

[0007] The inventive concept of the present invention is as follows: the epoxy resin color paste of the present invention comprises a resin, an acrylic copolymer modified polyurethane dispersant, an unsaturated carboxylic acid dispersant, and a pigment; the acrylic copolymer modified polyurethane dispersant is obtained by modifying polyurethane with an acrylic acid-styrene-butyl acrylate terpolymer.

[0008] The polyurethane segments in the specific type of acrylic copolymer-modified polyurethane dispersant of the present invention provide strong adsorption to the pigment surface, while the acrylic copolymer segments simultaneously create steric hindrance. The synergistic effect of these two groups significantly improves the dispersibility of the pigment, thereby enhancing the storage stability of the color paste. Furthermore, anchoring groups, such as the carboxyl (-COOH) groups in the dispersant, can bind to the pigment surface through ionic bonds, hydrogen bonds, and coordination bonds, allowing the dispersant to firmly adsorb to the surface of the pigment particles and increasing the pigment's dispersibility. Furthermore, the acrylic copolymer-modified polyurethane dispersant can increase the crosslinking degree of the epoxy resin, forming a three-dimensional network structure that can improve the mechanical strength of the coating.

[0009] In addition, there is a synergistic effect between specific types of acrylic copolymer modified polyurethane dispersants and unsaturated carboxylic acid dispersants. Through the joint action of two different types of dispersants, the pigment is more compatible in the epoxy color paste and can be better dispersed, which can take into account the stability of the color paste and paint, so that the epoxy resin color paste and epoxy floor coating have good storage stability, and the paint film obtained from the epoxy floor coating is not prone to floating color.

[0010] Therefore, a first aspect of the present invention provides an epoxy resin paste.

[0011] Specifically, the epoxy resin paste includes resin, acrylic copolymer modified polyurethane dispersant, unsaturated carboxylic acid dispersant and pigment;

[0012] The acrylic acid copolymer modified polyurethane dispersant is obtained by modifying polyurethane with acrylic acid-styrene-butyl acrylate terpolymer.

[0013] Preferably, the epoxy resin paste comprises, by mass, 55-100 parts of resin, 1.8-5.5 parts of acrylic copolymer modified polyurethane dispersant, 0.9-3.5 parts of unsaturated carboxylic acid dispersant and 10-15 parts of pigment.

[0014] Further preferably, the epoxy resin paste comprises, by mass, 60-90 parts of resin, 2-5 parts of acrylic copolymer modified polyurethane dispersant, 1-3 parts of unsaturated carboxylic acid dispersant and 10-15 parts of pigment.

[0015] Preferably, the epoxy resin paste further comprises a diluent.

[0016] Preferably, the epoxy resin paste comprises, by mass, 55-100 parts of resin, 1.8-5.5 parts of acrylic copolymer modified polyurethane dispersant, 0.9-3.5 parts of unsaturated carboxylic acid dispersant, 10-15 parts of pigment and 2.5-11 parts of diluent.

[0017] Further preferably, the epoxy resin paste comprises, by mass, 60-90 parts of resin, 2-5 parts of acrylic copolymer modified polyurethane dispersant, 1-3 parts of unsaturated carboxylic acid dispersant, 10-15 parts of pigment and 3-10 parts of diluent.

[0018] Preferably, the resin comprises epoxy resin.

[0019] Preferably, the unsaturated carboxylic acid dispersant includes a silicon-containing unsaturated carboxylic acid dispersant.

[0020] Preferably, the diluent comprises benzyl alcohol.

[0021] Preferably, the pigment includes at least one of carbon black, red pigment, and benzimidazolone pigment.

[0022] More preferably, the pigments include carbon black, red pigments and benzimidazolone pigments.

[0023] Preferably, the benzimidazolone pigment includes organic medium chrome yellow Pigment Yellow PY139WI.

[0024] The second aspect of the present invention provides a method for preparing the epoxy resin color paste described in the first aspect of the present invention.

[0025] Specifically, the preparation method of the epoxy resin paste includes the following steps:

[0026] The components of the epoxy resin paste are mixed and ground to prepare the epoxy resin paste.

[0027] Preferably, the preparation method of the epoxy resin paste comprises the following steps:

[0028] (I) firstly mixing a resin and a diluent and stirring; then adding an acrylic copolymer modified polyurethane dispersant and an unsaturated carboxylic acid dispersant and dispersing them uniformly to obtain a mixture;

[0029] (II) mixing the pigment and the mixture obtained in step (I), dispersing the mixture, and then grinding the mixture to obtain the epoxy resin paste.

[0030] Preferably, in step (I), the stirring speed is 450-900 r / min and the stirring time is 9-17 minutes; further preferably, in step (I), the stirring speed is 500-800 r / min and the stirring time is 10-15 minutes. The resin is fully diluted by stirring and dispersing.

[0031] Specifically, during the preparation of epoxy resin color paste, the raw material components are not added at the same time, but are added step by step, which can ensure that the dispersant is fully dispersed in the system before the pigment is added, providing good conditions for the subsequent dispersion of the pigment.

[0032] Preferably, in step (II), the dispersion speed is 1600-2500 r / min, and the dispersion time is 27-55 min; further preferably, the dispersion speed is 1800-2200 r / min, and the dispersion time is 30-50 min; further preferably, the dispersion speed is 2000 r / min.

[0033] Specifically, in step (II), the purpose of using a high dispersion speed for high-speed dispersion is to fully mix the pigment and dispersant and improve the dispersibility of the pigment. However, during the high-speed dispersion process, care should be taken to control the temperature to avoid excessively high temperatures that may cause degradation of the color paste performance.

[0034] Preferably, in step (II), the grinding is performed using a sand mill.

[0035] Preferably, the filling medium of the sand mill comprises zirconium beads.

[0036] Preferably, the particle size of the zirconium beads is 1-2 mm.

[0037] Preferably, after grinding, the fineness of the epoxy resin paste is less than 22 μm; further preferably, after grinding, the fineness of the epoxy resin paste is less than 20 μm.

[0038] Specifically, the color paste is ground to a certain fineness through the grinding action of the sand mill. During the grinding process, the fineness of the color paste is regularly tested to ensure that the fineness meets the requirements.

[0039] The present invention has no special limitation on the grinding time and the parameters of the sand mill. The grinding time and the parameters of the sand mill can be adjusted according to actual conditions to achieve the best grinding effect.

[0040] Preferably, the grinding process also includes a filtering process.

[0041] Preferably, the filtration is performed using filter paper, filter cloth or a filter to remove impurities and ensure the purity of the color paste.

[0042] Preferably, the preparation method of the acrylic acid copolymer modified polyurethane dispersant comprises the following steps:

[0043] (1) mixing polyether polyol, isophorone diisocyanate, and a catalyst, and reacting them; adding a chain extender to continue the reaction; and then adding a neutralizing agent to obtain a polyurethane prepolymer;

[0044] (2) mixing the polyurethane prepolymer obtained in step (1) with water to obtain a polyurethane prepolymer dispersion; then adding acrylic acid, styrene, butyl acrylate and an initiator, reacting, and distilling under reduced pressure to obtain the acrylic copolymer modified polyurethane dispersant.

[0045] Preferably, the amount of the polyether polyol is 27-45 parts by mass, the amount of isophorone diisocyanate is 9-22 parts by mass, the amount of the catalyst is 0.02-0.04 parts by mass, the amount of the chain extender is 1.8-5.5 parts by mass, the amount of water is 55-90 parts by mass, and the total amount of acrylic acid, styrene and butyl acrylate is 16-28 parts by mass.

[0046] Further preferably, the amount of the polyether polyol is 30-40 parts by mass, the amount of isophorone diisocyanate is 10-20 parts by mass, the amount of the catalyst is 0.02-0.04 parts by mass, the amount of the chain extender is 2-5 parts by mass, the amount of water is 60-80 parts by mass, and the total amount of acrylic acid, styrene and butyl acrylate is 18-25 parts by mass.

[0047] Preferably, the molar ratio of the chain extender to the neutralizer is 1:(0.8-1.2); further preferably, the molar ratio of the chain extender to the neutralizer is 1:(0.9-1.1); further preferably, the molar ratio of the chain extender to the neutralizer is 1:1.

[0048] Preferably, the amount of the initiator used is 1.0-2.0% of the total mass of acrylic acid, styrene and butyl acrylate; further preferably, the amount of the initiator used is 1.3-1.7% of the total mass of acrylic acid, styrene and butyl acrylate; even more preferably, the amount of the initiator used is 1.5% of the total mass of acrylic acid, styrene and butyl acrylate.

[0049] Preferably, when preparing the acrylic copolymer modified polyurethane dispersant, in step (1), during the reaction process after the polyether polyol, isophorone diisocyanate and catalyst are mixed, the reaction temperature is 70-85°C.

[0050] Further preferably, during the reaction process after the polyether polyol, isophorone diisocyanate and catalyst are mixed, the reaction temperature is 75-80°C.

[0051] Preferably, in step (1), the reaction temperature is controlled so that the molar ratio of isocyanate groups to hydroxyl groups is (1.5-2.2):1; further preferably, the reaction temperature is controlled so that the molar ratio of isocyanate groups to hydroxyl groups is (1.6-2.0):1; even further preferably, the reaction temperature is controlled so that the molar ratio of isocyanate groups to hydroxyl groups is 1.8:1.

[0052] Preferably, in step (1), during the reaction process after the polyether polyol, isophorone diisocyanate and catalyst are mixed, the reaction time is 1.5-2.5 hours; further preferably, the reaction time is 1.8-2.2 hours; further preferably, the reaction time is 2 hours.

[0053] Preferably, in step (1), after the continued reaction, the temperature is first lowered to 32-50°C, and then the neutralizer is added; further preferably, after the continued reaction, the temperature is first lowered to 35-45°C, and then the neutralizer is added; even more preferably, after the continued reaction, the temperature is first lowered to 40°C, and then the neutralizer is added.

[0054] Specifically, the polyurethane prepolymer prepared in step (1) is an anionic polyurethane prepolymer.

[0055] Preferably, the catalyst comprises dibutyltin dilaurate (DBTDL).

[0056] Preferably, the chain extender comprises dimethylolpropionic acid (DMPA).

[0057] Preferably, the neutralizing agent includes triethylamine (TEA), and the carboxyl group is neutralized by the neutralizing agent.

[0058] Preferably, in step (2), the polyurethane prepolymer is first dissolved in acetone to reduce the viscosity of the polyurethane prepolymer, and then mixed with water.

[0059] Preferably, in step (2), water is slowly added dropwise to the polyurethane prepolymer under high-speed shearing conditions for emulsification to form a stable prepolymer dispersion.

[0060] Preferably, the rotation speed of the high-speed shearing is 2000-3000 rpm; further preferably, the rotation speed of the high-speed shearing is 2200-2700 rpm; further preferably, the rotation speed of the high-speed shearing is 2500 rpm.

[0061] Preferably, in step (2), the mass ratio of acrylic acid, styrene and butyl acrylate is 1:(1.6-2.5):(0.8-1.2); further preferably, the mass ratio of acrylic acid, styrene and butyl acrylate is 1:(1.8-2.2):(0.9-1.1); even further preferably, the mass ratio of acrylic acid, styrene and butyl acrylate is 1:2:1.

[0062] Preferably, the initiator comprises ammonium persulfate (APS).

[0063] Preferably, in step (2), the reaction temperature is 65-85°C, and the reaction time is 3-5h; further preferably, the reaction temperature is 70-80°C, and the reaction time is 3.5-4.5h; even further preferably, the reaction temperature is 75°C, and the reaction time is 4h.

[0064] Specifically, the reaction in step (2) is a free radical copolymerization reaction.

[0065] Specifically, in step (2), the purpose of the reduced pressure distillation is to remove the acetone added to reduce the viscosity of the polyurethane prepolymer.

[0066] Preferably, in step (2), the reduced pressure distillation further comprises adjusting the pH to alkaline and filtering, and a light blue translucent liquid is obtained after filtration.

[0067] Preferably, an alkaline substance is used to adjust the pH to alkaline.

[0068] Preferably, the alkaline substance includes aqueous ammonia.

[0069] A third aspect of the present invention provides a floor coating.

[0070] Specifically, the floor coating includes the epoxy resin color paste described in the first aspect of the present invention.

[0071] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0072] (1) The acrylic copolymer modified polyurethane dispersant of the present invention is obtained by modifying polyurethane with an acrylic acid-styrene-butyl acrylate terpolymer, wherein the polyurethane chain segment provides a strong adsorption effect on the pigment surface, and the acrylic copolymer chain segment forms a steric hindrance. The synergistic effect of the two can significantly improve the dispersibility of the pigment and improve the storage stability of the color paste. At the same time, the anchoring group, such as the carboxyl group (-COOH) in the dispersant, can be combined with the pigment surface through ionic bonds, hydrogen bonds, coordination bonds, etc., so that the dispersant is firmly adsorbed on the surface of the pigment particles, increasing the dispersibility of the pigment. In addition, the specific type of acrylic copolymer modified polyurethane dispersant of the present invention can increase the crosslinking degree of the epoxy resin, form a three-dimensional network structure, and improve the mechanical strength of the coating.

[0073] (2) The specific types of acrylic copolymer modified polyurethane dispersants and unsaturated carboxylic acid dispersants of the present invention have a synergistic effect. Through the chemical modification of the acrylic copolymer modified polyurethane dispersant and the physical modification of the physical mixture of two different types of dispersants, the pigment is better dispersed in the epoxy paste, especially for pigments or fillers that are difficult to disperse. The effect is more significant, and the stability of the paste and paint can be taken into account, so that the epoxy resin paste and epoxy floor coating have good storage stability, and the paint film obtained by the epoxy floor coating is not easy to float or bloom. In addition, the epoxy resin is used as a paste carrier and is the same material as the main body of the epoxy floor coating, which is more compatible and has good compatibility.

[0074] (3) The ester groups (-COO-) generated by the esterification reaction between the hydroxyl groups in the acrylic copolymer modified polyurethane dispersant of the present invention and the epoxy groups in the epoxy resin can also improve the uniformity of the color paste, improve the fluidity of the coating, help the coating to exhibit better self-leveling properties during the drying process, and reduce surface defects of the coating.

[0075] (4) The preparation process of the present invention is simple, and the fineness is controlled by grinding to enhance the dispersibility, color development and coloring of the color paste in the paint. DETAILED DESCRIPTION

[0076] In order to make the technical solution of the present invention more clearly understood by those skilled in the art, the following examples are given for illustration. It should be noted that the following examples do not limit the scope of protection claimed by the present invention.

[0077] Unless otherwise specified, the raw materials, reagents, or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0078] The sources of the raw materials of the epoxy resin pastes of the present invention and the comparative examples are as follows:

[0079] YN-128 resin; purchased from Jiangsu Yangnong Jinhu Chemical Co., Ltd.;

[0080] MA-100 carbon black: purchased from Mitsubishi Chemical Corporation;

[0081] Organic medium chrome yellow Pigment Yellow PY139WI: purchased from Guangzhou Chenghai New Material Technology Co., Ltd.

[0082] Color red 7254DB: purchased from Guangzhou Chenghai New Material Technology Co., Ltd.

[0083] Structured polymer dispersants 680U: purchased from UCAR Chemical Co., Ltd.

[0084] End-group modified polyurethane dispersant 560S: purchased from UCAR Chemical Co., Ltd.;

[0085] Silicon-containing unsaturated carboxylic acid dispersant S: purchased from UCAR Chemical Co., Ltd.

[0086] The raw material components and amounts of the epoxy resin pastes of Examples 1-3 and Comparative Examples 1-4 of the present invention are shown in Table 1.

[0087] Table 1: Raw material components and amounts (parts by mass) of epoxy resin pastes of Examples 1-3 and Comparative Examples 1-4 of the present invention

[0088]

[0089] In Table 1, “ / ” indicates that no addition was made.

[0090] Example 1

[0091] The raw material components and amounts of epoxy resin paste in Example 1 are shown in Table 1.

[0092] The preparation method of the above-mentioned epoxy resin paste comprises the following steps:

[0093] (1) mixing a resin with a diluent, stirring at a speed of 500 r / min for 10 minutes to fully dilute; then adding an acrylic copolymer modified polyurethane dispersant and a silicon-containing unsaturated carboxylic acid dispersant to ensure that the dispersant is fully dispersed in the system before the pigment is added, providing good conditions for subsequent dispersion of the pigment, and obtaining a mixture after the dispersant is uniformly dispersed;

[0094] (II) adding pigment to the mixture obtained in step (I) and performing high-speed dispersion at a speed of 2000 r / min for 30 min to fully mix the pigment and the dispersant and improve the dispersibility of the pigment; during the high-speed dispersion process, the system temperature will rise, so the temperature needs to be controlled below 80°C to avoid excessive temperature causing a decrease in the performance of the color paste; transferring the high-speed dispersed mixture to a sand mill for grinding, wherein the filling medium in the sand mill is zirconium beads with a particle size of 1-2 mm, and the fineness of the color paste is reduced to less than 20 μm through the grinding action of the sand mill, and during the grinding process, the fineness of the color paste is regularly checked to ensure that the fineness meets the requirements; finally, the ground color paste is filtered with filter paper to remove impurities therein to ensure the purity of the color paste, thereby obtaining an epoxy resin color paste.

[0095] For fineness, a 50μm fineness meter is used to test according to the method specified in the standard "GB / T 6753.1-2007 Paints, varnishes and printing inks - Determination of fineness of grinding".

[0096] The preparation method of acrylic acid copolymer modified polyurethane dispersant comprises the following steps:

[0097] (1) 38.5 parts of polyether diol (molecular weight 2000Da, difunctionality) and 13.5 parts of isophorone diisocyanate (IPDI) were mixed, and under nitrogen protection, 0.02 parts of dibutyltin dilaurate (DBTDL) catalyst was added. The reaction temperature was controlled at 75-80°C to make the NCO / OH molar ratio reach 1.8:1. After reacting for 2 hours, 2.2 parts of dimethylolpropionic acid (DMPA) was added for chain extension, and the reaction was continued until the NCO content reached the theoretical value; after cooling to 40°C, triethylamine (TEA) in an equal molar ratio to DMPA was added to neutralize the carboxyl group to obtain an anionic polyurethane prepolymer;

[0098] (2) dissolving the anionic polyurethane prepolymer obtained in step (1) in acetone to reduce the viscosity, and slowly adding 77 parts of deionized water under high-speed shear conditions of 2500 rpm for emulsification to form a stable prepolymer dispersion; adding 23.1 parts of a mixed monomer of acrylic acid (AA), styrene (St) and butyl acrylate (BA) (the mass ratio of AA, St and BA is 1:2:1) to the prepolymer dispersion, and adding 1.5% of ammonium persulfate (APS) as an initiator accounting for the total mass of the monomers, and conducting a free radical copolymerization reaction at a temperature of 75°C for 4 hours. After the reaction is completed, the acetone is removed by reduced pressure distillation to obtain an acrylic acid-polyurethane hybrid dispersion with a solid content of 30%, and adjusting the pH to 7.5 with ammonia water. After filtering, a light blue translucent liquid is obtained, which is an acrylic acid copolymer modified polyurethane dispersant.

[0099] Example 2

[0100] The raw material components and amounts of the epoxy resin paste of Example 2 are shown in Table 1.

[0101] The preparation method of the above-mentioned epoxy resin paste comprises the following steps:

[0102] (1) mixing the resin and the diluent, stirring at a speed of 650 r / min for 12 minutes to fully dilute; then adding an acrylic copolymer modified polyurethane dispersant and a silicon-containing unsaturated carboxylic acid dispersant to ensure that the dispersant is fully dispersed in the system before the pigment is added, providing good conditions for subsequent dispersion of the pigment, and obtaining a mixture after the dispersant is uniformly dispersed;

[0103] (II) adding pigment to the mixture obtained in step (I) and performing high-speed dispersion at a speed of 2000 r / min for 40 min to fully mix the pigment and the dispersant and improve the dispersibility of the pigment; during the high-speed dispersion process, the system temperature will rise, so the temperature needs to be controlled below 80°C to avoid excessive temperature causing a decrease in the performance of the color paste; transferring the high-speed dispersed mixture to a sand mill for grinding, the filling medium in the sand mill is zirconium beads with a particle size of 1-2 mm, and the fineness of the color paste is reduced to less than 20 μm through the grinding action of the sand mill, and during the grinding process, the fineness of the color paste is regularly checked to ensure that the fineness meets the requirements; finally, the ground color paste is filtered with a filter cloth to remove impurities therein to ensure the purity of the color paste, thereby obtaining an epoxy resin color paste.

[0104] The test method of fineness is the same as that in Example 1.

[0105] The preparation method of acrylic acid copolymer modified polyurethane dispersant comprises the following steps:

[0106] (1) 38.5 parts of polyether diol (molecular weight 2000Da, difunctionality) and 13.5 parts of isophorone diisocyanate (IPDI) were mixed, and under nitrogen protection, 0.02 parts of dibutyltin dilaurate (DBTDL) catalyst was added. The reaction temperature was controlled at 75-80°C to make the NCO / OH molar ratio reach 1.8:1. After reacting for 2 hours, 2.2 parts of dimethylolpropionic acid (DMPA) was added for chain extension, and the reaction was continued until the NCO content reached the theoretical value; after cooling to 40°C, triethylamine (TEA) in an equal molar ratio to DMPA was added to neutralize the carboxyl group to obtain an anionic polyurethane prepolymer;

[0107] (2) dissolving the anionic polyurethane prepolymer obtained in step (1) in acetone to reduce the viscosity, and slowly adding 77 parts of deionized water under high-speed shear conditions of 2500 rpm for emulsification to form a stable prepolymer dispersion; adding 23.1 parts of a mixed monomer of acrylic acid (AA), styrene (St) and butyl acrylate (BA) (the mass ratio of AA, St and BA is 1:2:1) to the prepolymer dispersion, and adding 1.5% of ammonium persulfate (APS) as an initiator accounting for the total mass of the monomers, and conducting a free radical copolymerization reaction at a temperature of 75°C for 4 hours. After the reaction is completed, the acetone is removed by reduced pressure distillation to obtain an acrylic acid-polyurethane hybrid dispersion with a solid content of 30%, and adjusting the pH to 7.5 with ammonia water. After filtering, a light blue translucent liquid is obtained, which is an acrylic acid copolymer modified polyurethane dispersant.

[0108] Example 3

[0109] The raw material components and amounts of the epoxy resin paste of Example 3 are shown in Table 1.

[0110] The preparation method of the above-mentioned epoxy resin paste comprises the following steps:

[0111] (1) mixing a resin and a diluent, stirring at a speed of 800 r / min for 15 minutes to fully dilute; then adding an acrylic copolymer modified polyurethane dispersant and a silicon-containing unsaturated carboxylic acid dispersant to ensure that the dispersant is fully dispersed in the system before the pigment is added, providing good conditions for subsequent dispersion of the pigment, and obtaining a mixture after the dispersant is uniformly dispersed;

[0112] (II) adding pigment to the mixture obtained in step (I) and performing high-speed dispersion at a speed of 2000 r / min for 50 min to fully mix the pigment and the dispersant and improve the dispersibility of the pigment; during the high-speed dispersion process, the system temperature will rise, so the temperature needs to be controlled below 80°C to avoid excessive temperature causing a decrease in the performance of the color paste; transferring the high-speed dispersed mixture to a sand mill for grinding, the filling medium in the sand mill is zirconium beads with a particle size of 1-2 mm, and the fineness of the color paste is reduced to less than 20 μm through the grinding action of the sand mill, and during the grinding process, the fineness of the color paste is regularly checked to ensure that the fineness meets the requirements; finally, the ground color paste is filtered with filter paper to remove impurities therein to ensure the purity of the color paste, thereby obtaining an epoxy resin color paste.

[0113] The test method of fineness is the same as that in Example 1.

[0114] The preparation method of acrylic acid copolymer modified polyurethane dispersant comprises the following steps:

[0115] (1) 38.5 parts of polyether diol (molecular weight 2000Da, difunctionality) and 13.5 parts of isophorone diisocyanate (IPDI) were mixed, and under nitrogen protection, 0.02 parts of dibutyltin dilaurate (DBTDL) catalyst was added. The reaction temperature was controlled at 75-80°C to make the NCO / OH molar ratio reach 1.8:1. After reacting for 2 hours, 2.2 parts of dimethylolpropionic acid (DMPA) was added for chain extension, and the reaction was continued until the NCO content reached the theoretical value; after cooling to 40°C, triethylamine (TEA) in an equal molar ratio to DMPA was added to neutralize the carboxyl group to obtain an anionic polyurethane prepolymer;

[0116] (2) dissolving the anionic polyurethane prepolymer obtained in step (1) in acetone to reduce the viscosity, and slowly adding 77 parts of deionized water under high-speed shear conditions of 2500 rpm for emulsification to form a stable prepolymer dispersion; adding 23.1 parts of a mixed monomer of acrylic acid (AA), styrene (St) and butyl acrylate (BA) (the mass ratio of AA, St and BA is 1:2:1) to the prepolymer dispersion, and adding 1.5% of ammonium persulfate (APS) as an initiator accounting for the total mass of the monomers, and conducting a free radical copolymerization reaction at a temperature of 75°C for 4 hours. After the reaction is completed, the acetone is removed by reduced pressure distillation to obtain an acrylic acid-polyurethane hybrid dispersion with a solid content of 30%, and adjusting the pH to 7.5 with ammonia water. After filtering, a light blue translucent liquid is obtained, which is an acrylic acid copolymer modified polyurethane dispersant.

[0117] Comparative Example 1

[0118] The only difference between Comparative Example 1 and Example 1 is that Comparative Example 1 uses the same amount of structural polymer dispersant 680U replaces the silicon-containing unsaturated carboxylic acid dispersant of Example 1 S, other aspects are the same as in Example 1.

[0119] Comparative Example 2

[0120] The only difference between Comparative Example 2 and Example 1 is that Comparative Example 2 uses an equal amount of end-group modified polyurethane dispersant 560S replaces the silicon-containing unsaturated carboxylic acid dispersant of Example 1 S, other aspects are the same as in Example 1.

[0121] Comparative Example 3

[0122] The only difference between Comparative Example 3 and Example 1 is that Comparative Example 3 uses the same amount of structural polymer dispersant 680U and terminal modified polyurethane dispersant 560S replaces the acrylic copolymer modified polyurethane dispersant and silicon-containing unsaturated carboxylic acid dispersant of Example 1 S, other aspects are the same as in Example 1.

[0123] Comparative Example 4

[0124] The only difference between Comparative Example 4 and Example 1 is that Comparative Example 4 uses an equal amount of structural polymer dispersant 680U replaces the acrylic copolymer modified polyurethane dispersant in Example 1, and the rest are the same as in Example 1.

[0125] Performance Testing

[0126] The performance tests of the epoxy resin color pastes prepared in Examples 1-3 and Comparative Examples 1-4 were carried out. The test items and test methods are as follows:

[0127] Finger rubbing color difference ΔE test: The epoxy resin color paste prepared in Examples 1-3 and Comparative Examples 1-4 was added at a mass fraction of 1% to the NSP-600 solvent-free epoxy self-leveling floor paint base (not toned) containing 9% (mass fraction) titanium white paste (purchased from Nippon Paint (Qingyuan) Co., Ltd.), and stirred evenly to obtain the paint; the paint and the curing agent (using component B in NSP-600) were molded on a paper card using a 500μm wet film preparation device at a mass ratio of 5:1. After 30 minutes, the finger was used to rub the same position in a circle for 20-30 times. After the film was completely dry, the finger-rubbed part and the other parts were tested with a colorimeter to obtain the finger-rubbed color difference ΔE.

[0128] Storage stability: The epoxy resin paste prepared in Examples 1-3 and Comparative Examples 1-4 was added at a mass fraction of 1% to an NSP-600 solvent-free epoxy self-leveling floor paint base (not toned) containing 9% (mass fraction) titanium white slurry (purchased from Nippon Paint (Qingyuan) Co., Ltd.), and stirred evenly to obtain a paint; then, the paint was placed at room temperature and 50°C for 7 days, and a color difference test was performed using a colorimeter by scraping a bimodal card to obtain a heat storage ΔE of the paint;

[0129] The epoxy resin color paste is also subjected to a storage stability test, and the test method is the same as the storage stability test method of the above-mentioned paint to obtain the color paste heat storage ΔE.

[0130] Construction interval color difference test: The epoxy resin color paste prepared in Examples 1-3 and Comparative Examples 1-4 was added to NSP-600 solvent-free epoxy self-leveling floor paint base (not toned) containing 9% (mass fraction) titanium white slurry (purchased from Nippon Paint (Qingyuan) Co., Ltd.) at a mass fraction of 1%, and stirred evenly to obtain a paint; the paint and the curing agent (using component B in NSP-600) were stirred evenly at a ratio of 5:1, and the mixture was heated at 0.8 kg / m 2 Use the appropriate amount for construction, and use the bun coating method to apply half of it on the cement fiber cement board. After 20 minutes, overlap and apply the other half. After the paint film is dry, use a colorimeter to test the color difference between the overlap and both sides.

[0131] The compatibility of epoxy resin color paste and paint is evaluated by rubbing color difference; the storage stability of epoxy resin color paste is evaluated by color paste thermal storage △E and construction interval color difference; the dispersibility of epoxy resin color paste in paint is evaluated by paint thermal storage △E, and the storage stability of paint is also explained.

[0132] The performance test results of the epoxy resin pastes of Examples 1-3, Comparative Examples 1-4, and the paints (epoxy floor coatings) prepared from the epoxy resin pastes are shown in Table 2.

[0133] Table 2: Performance test results of epoxy resin pastes of Examples 1-3, Comparative Examples 1-4, and paints prepared from epoxy resin pastes

[0134]

[0135] As can be seen from Table 2, the acrylic copolymer modified polyurethane dispersant of the present invention works synergistically with the unsaturated carboxylic acid dispersant to disperse the pigment, so that the pigment has good dispersibility in the epoxy system, which can make the epoxy resin paste have good storage stability and good dispersibility in the colored paint, thereby making the colored paint have good storage stability and not easy to cause floating and floating.

[0136] Comparative Examples 1-4 employ a single acrylic copolymer-modified polyurethane dispersant or unsaturated carboxylic acid dispersant, or employ a combination of other dispersants, resulting in higher rubbing color difference ΔE, color paste heat storage ΔE, paint heat storage ΔE, and 20-minute construction interval ΔE than Example 1, particularly the color paste heat storage ΔE and paint heat storage ΔE. This demonstrates that the acrylic copolymer-modified polyurethane dispersant and the unsaturated carboxylic acid dispersant in the present invention are both indispensable, and their synergistic effect ensures good pigment dispersion in the epoxy system, ensuring the storage stability of the epoxy resin color paste, and good dispersion of the epoxy resin color paste in the paint, ensuring the storage stability of the paint.

[0137] In summary, the specific types of acrylic copolymer modified polyurethane dispersants and unsaturated carboxylic acid dispersants of the present invention have a synergistic effect. Through the chemical modification of the acrylic copolymer modified polyurethane dispersant and the physical modification of the physical mixing of two different types of dispersants, the pigment is fully dispersed in the epoxy resin paste, and the stability of the paste and the paint can be taken into account, so that the epoxy resin paste and the epoxy floor coating have good storage stability, and the paint film obtained by the epoxy floor coating is not easy to float and bloom.

[0138] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An epoxy resin paste, characterized in that: It includes resin, acrylic copolymer modified polyurethane dispersant, unsaturated carboxylic acid dispersant and pigment; The acrylic acid copolymer modified polyurethane dispersant is obtained by modifying polyurethane with acrylic acid-styrene-butyl acrylate terpolymer.

2. The epoxy resin paste according to claim 1, characterized in that Calculated by mass, the epoxy resin color paste includes 55-100 parts of resin, 1.8-5.5 parts of acrylic copolymer modified polyurethane dispersant, 0.9-3.5 parts of unsaturated carboxylic acid dispersant and 10-15 parts of pigment.

3. The epoxy resin paste according to claim 1, characterized in that The epoxy resin paste further comprises a diluent.

4. The epoxy resin paste according to claim 3, characterized in that Calculated by mass, the epoxy resin color paste includes 55-100 parts of resin, 1.8-5.5 parts of acrylic copolymer modified polyurethane dispersant, 0.9-3.5 parts of unsaturated carboxylic acid dispersant, 10-15 parts of pigment and 2.5-11 parts of diluent.

5. The epoxy resin paste according to any one of claims 1 to 4, characterized in that The resin includes epoxy resin; and / or the unsaturated carboxylic acid dispersant includes a silicon-containing unsaturated carboxylic acid dispersant.

6. The method for preparing the epoxy resin paste according to any one of claims 1 to 5, characterized in that: The following steps are involved: The components of the epoxy resin paste are mixed and ground to prepare the epoxy resin paste.

7. The preparation method according to claim 6, characterized in that The preparation method of the acrylic acid copolymer modified polyurethane dispersant comprises the following steps: (1) mixing polyether polyol, isophorone diisocyanate, and a catalyst, and reacting them; adding a chain extender to continue the reaction; and then adding a neutralizing agent to obtain a polyurethane prepolymer; (2) mixing the polyurethane prepolymer obtained in step (1) with water to obtain a polyurethane prepolymer dispersion; then adding acrylic acid, styrene, butyl acrylate and an initiator, reacting, and distilling under reduced pressure to obtain the acrylic copolymer modified polyurethane dispersant.

8. The preparation method according to claim 7, characterized in that The amount of the polyether polyol is 27-45 parts by mass, the amount of isophorone diisocyanate is 9-22 parts by mass, the amount of the catalyst is 0.02-0.04 parts by mass, the amount of the chain extender is 1.8-5.5 parts by mass, the amount of water is 55-90 parts by mass, and the total amount of acrylic acid, styrene and butyl acrylate is 16-28 parts by mass; and / or, the molar ratio of the chain extender to the neutralizer is 1:(0.8-1.2); And / or, the amount of the initiator used is 1.0-2.0% of the total mass of acrylic acid, styrene and butyl acrylate.

9. The preparation method according to claim 7, characterized in that In step (1), during the reaction process after the polyether polyol, isophorone diisocyanate and catalyst are mixed, the reaction temperature is 70-85° C.; And / or, in step (1), during the reaction process after the polyether polyol, isophorone diisocyanate and catalyst are mixed, the reaction time is 1.5-2.5h; And / or, in step (2), the mass ratio of acrylic acid, styrene and butyl acrylate is 1:(1.6-2.5):(0.8-1.2); And / or, in step (2), the reaction temperature is 65-85°C, and the reaction time is 3-5h.

10. A floor coating, characterized in that: The invention comprises the epoxy resin paste according to any one of claims 1 to 5.

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