A water-based acrylic copolymer microsphere suspension, a preparation method thereof, and application thereof in preparing a highly light-transmitting self-matting topcoat

Abstract

The present invention provides an aqueous acrylate copolymer microsphere suspension, a preparation method thereof, and an application thereof in preparing a highly light-transmitting self-matting topcoat. The aqueous acrylate copolymer microsphere suspension is prepared from styrene, methyl methacrylate, butyl acrylate, methacrylic acid, (meth)hydroxyethyl acrylate, and 1,4-butanediol dimethacrylate by microsuspension polymerization. The aqueous acrylate copolymer microsphere suspension has water absorption and water loss shrinkage properties, and the suspension has a good protective effect (such as abrasion resistance, water resistance, etc.) after film formation. The topcoat prepared using the aqueous acrylate copolymer microsphere suspension of the present invention can ensure that the coating has good light transmission performance on the basis of excellent matting performance, and has high abrasion resistance and high water resistance at the same time.

Description

Technical Field

[0001] The invention relates to a water-based acrylic copolymer microsphere suspension and a preparation method thereof and application of the suspension in preparing a highly light-transmitting self-matting topcoat, such as being used as a water-based textured coating, a water-based varnish for printed matter and a topcoat for wooden furniture. Background Art

[0002] With the control of VOCs emissions by the coatings, adhesives and printing and packaging industries, many fields have begun to ban solvent-based coatings, solvent-based adhesives and solvent-based adhesives. The water-based nature of coatings, adhesives and printing inks has become a challenge and opportunity for manufacturers and application companies. Many properties of water-based coatings and printing inks, including construction performance and performance after drying, are far inferior to traditional solvent-based products, such as water resistance, hardness, scratch resistance, ink resolubility, actual drying speed, etc. Especially in the architectural coating industry, water-based multi-color coatings and water-based real stone paints are thick coatings. In order to achieve fast drying, the hydrophilicity of the film-forming emulsion polymer must be increased, which often leads to a significant decrease in the water resistance and whitening of the coating when exposed to water. Water-based printing inks also have similar problems. In order to improve the solubility of the subsequent printing, a large amount of water-based dispersion resin is used, which reduces the water resistance of the ink layer. Therefore, water-based texture coatings must be covered to improve the water resistance of the coating. In the field of water-based printing inks, especially the surface printing ink layer, varnish must be applied to improve the water resistance and wear resistance of the printed product. The varnish of texture coatings and the varnish of printing inks are both highly transparent varnishes. After varnishing or varnishing, the reflective ability of the coating increases, leading to fatal light pollution problems such as glare. Therefore, the finish coating must be matte designed. Sometimes matte finish is also a natural pursuit to improve the beauty of printed products or coatings.

[0003] With the improvement of living standards, aesthetic concepts have undergone qualitative changes. Water-based multi-color and water-based real stone paints have become the mainstream in the field of architectural coatings. The glazing consumption of their topcoats and water-based printing inks is very large. The current matting measures are mostly to add silica-based matting powder during the preparation of varnish. Although the addition of matting powder can reduce light reflection, it seriously affects the light transmittance of the topcoat, causing serious distortion of the color of the topcoat or the printed product.

[0004] Many research units are designing and developing water-swellable microspheres. Zhuang Ruobin et al. studied terpolymer microspheres in the preparation of PGMA-MMA-EGDMA copolymer cross-linked microspheres by suspension polymerization. The results showed that by regularly and purposefully adjusting the reaction conditions in the suspension polymerization process, microspheres with a particle size of 100 to 400 μm can generally be prepared. The particle size of the extinction microspheres prepared by the suspension method is relatively large, and the roughness depth required to achieve extinction is 1.1 μm, which is far beyond the required size, and it is difficult to control the particle size of the microspheres prepared by the suspension method to a lower level.

[0005] Generally speaking, polymer microspheres prepared by emulsion polymerization are more likely to show ideal effects in terms of stability and particle size distribution, but the polymerization process is limited and traditional emulsion polymerization is difficult to achieve micron-level microspheres.

[0006] Waterborne polyurethane dispersions can also be used to produce self-matting topcoat varnishes or varnishes through structural design, but due to the phase separation phenomenon, the transmittance of the paint film decreases, resulting in color and saturation distortion.

[0007] Although there are many studies on the preparation of matte coatings, most of them focus on the optimization of matte performance. The improvement of coating transmittance is often limited to the singleness of coating components. This also makes it difficult for topcoats on the market to ensure a balance between matte performance and transmittance. Therefore, the market is in urgent need of a water-based acrylic copolymer emulsion topcoat that has good matte performance and transmittance, is resistant to abrasion and water, and can provide good protection for primers to replace existing topcoats. Summary of the invention

[0008] In view of the above problems existing in the prior art, the present invention provides an aqueous acrylate copolymer microsphere suspension and a preparation method thereof, wherein an aqueous acrylate copolymer microsphere suspension having water absorption swelling and water loss shrinkage properties is prepared by microsuspension polymerization reaction, and the suspension has good protective effects (such as abrasion resistance, water resistance, etc.) after film formation. The topcoat prepared using the aqueous acrylate copolymer microsphere suspension of the present invention can ensure that the coating has good light transmission properties on the basis of excellent matting properties, and has high abrasion resistance and high water resistance.

[0009] To achieve the above object, the present invention adopts the following technical solution:

[0010] The present invention provides an aqueous acrylic ester copolymer microsphere suspension, which is prepared by microsuspension polymerization of the following polymerizable monomer components in parts by mass:

[0011] Styrene (St) 1.0-10.0 parts, for example 2.0 parts, 3.0 parts, 4.0 parts, 5.0 parts, 6.0 parts, 7.0 parts, 8.0 parts, 9.0 parts, preferably 3.0-6.0 parts;

[0012] Methyl methacrylate (MMA) 0.5-5.0 parts, for example 0.2 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.5 parts, 4.0 parts, 4.5 parts, preferably 1.0-3.0 parts;

[0013] Butyl acrylate (BA) 1.0-10.0 parts, for example 2.0 parts, 3.0 parts, 4.0 parts, 5.0 parts, 6.0 parts, 7.0 parts, 8.0 parts, 9.0 parts, preferably 2.3-6.0 parts;

[0014] Methacrylic acid (MAA) 1.0-10.0 parts, for example 1.5 parts, 2.5 parts, 3.5 parts, 4.5 parts, 5.5 parts, 6.5 parts, 7.5 parts, 8.5 parts, 9.5 parts, preferably 4.5-6.0 parts;

[0015] 0.5-5.0 parts of hydroxyethyl (meth)acrylate, for example, 0.2 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.5 parts, 4.0 parts, 4.5 parts, preferably 1.0-3.0 parts;

[0016] 1,4-Butanediol dimethacrylate (BGDMA) 0.01-0.3 parts, for example 0.02 parts, 0.07 parts, 0.12 parts, 0.17 parts, 0.22 parts, 0.27 parts, preferably 0.05-0.10 parts.

[0017] In some specific embodiments, the hydroxyethyl (meth)acrylate monomer is selected from any one of hydroxyethyl acrylate (HEA) and hydroxyethyl methacrylate or a combination of both, preferably hydroxyethyl acrylate.

[0018] In some specific embodiments, based on the total weight of the polymerized monomer components, the amount of methacrylic acid is 13-36.5%, such as 17%, 22%, 27%, 32%, preferably 20-25%. The amount of methacrylic acid is controlled and adjusted within this specific range, and its carboxyl group can be used to make the copolymer microspheres have a certain water absorption performance, while not affecting the reaction stability and the morphology of the microspheres.

[0019] In some specific embodiments, based on the total weight of the polymerized monomer components, the amount of hydroxyethyl (meth)acrylate is 5-30%, such as 10%, 15%, 20%, 25%, preferably 10-20%. Controlling the amount of hydroxyethyl (meth)acrylate within this range can not only give the copolymerized microspheres stronger hydrophilicity, but also improve the strength of the paint film through the reaction between the curing agent component and the film forming process.

[0020] The aqueous acrylic copolymer microsphere suspension of the present invention has microspheres with a particle size of 2-10 μm, preferably 4-7 μm.

[0021] The aqueous acrylate copolymer microsphere suspension of the present invention has a solid content of 15-36wt%, preferably 20-25wt%.

[0022] In the present invention, styrene, methyl methacrylate, butyl acrylate, methacrylic acid, (meth) hydroxyethyl acrylate are used as polymerization monomers and 1,4-butanediol dimethacrylate is used as a cross-linking monomer, and the aqueous acrylate copolymer microsphere suspension is prepared by micro-suspension polymerization. The copolymer microsphere has water absorption and swelling, water loss and shrinkage properties. Using it as a matting agent component can not only solve the compatibility problem between the matting agent and the film-forming material, but also optimize the light transmittance of the coating, thereby achieving dual optimization and balance of the matting and light transmittance of the topcoat coating. At the same time, the functional monomer methacrylic acid enables the copolymer microsphere to have a certain water absorption property, and the volume change rate of the copolymer microsphere before and after drying can be adjusted by changing the amount of the methacrylic acid monomer, so that the microsphere component can exert excellent matting performance. In addition, the hydroxyethyl (meth)acrylate introduced into the monomer component can provide the copolymer microspheres with stronger hydrophilicity, making them have a higher water absorption rate, and can also react with the curing agent during the film-forming process to further improve the strength and resistance of the paint film, thereby providing a better protective effect for the primer.

[0023] The aqueous acrylate copolymer microsphere suspension of the present invention is obtained by a microsuspension polymerization method, which is a polymerization method known in the prior art. The technician can use any feasible microsuspension polymerization method to prepare it;

[0024] In some specific embodiments, the raw materials for preparing the aqueous acrylate copolymer microsphere suspension of the present invention may also optionally include some auxiliary agents, such as emulsifiers, initiators, dispersants, stabilizers, water, etc. These auxiliary agents are conventionally selected in the art, and technicians can screen them as needed. The present invention has no special requirements for their types and amounts.

[0025] Preferably, the emulsifier is selected from any one or a combination of at least two of sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (SDBS), and allyloxy nonylphenol polyoxyethylene ether ammonium sulfate (SE-10N);

[0026] Preferably, the emulsifier is used in an amount of 0.01-0.6 parts, more preferably 0.05-0.2 parts.

[0027] Preferably, the initiator is selected from dibenzoyl peroxide (BPO) and / or azobisisobutyronitrile (AIBN);

[0028] Preferably, the initiator is used in an amount of 0.05-1 part, more preferably 0.1-0.5 part.

[0029] Preferably, the dispersant is selected from hydroxymethylpropyl cellulose (HPMC) and / or polyvinyl alcohol (PVA);

[0030] Preferably, the amount of the dispersant is 0.5-10 parts, more preferably 1.0-6.0 parts.

[0031] Preferably, the stabilizer is selected from any one or a combination of at least two of sodium nitrite (NaNO2), hexadecanol (CA), and hexadecane;

[0032] Preferably, the amount of the stabilizer is 0.01-0.4 parts, more preferably 0.05-0.2 parts.

[0033] Preferably, the amount of water is 63-86 parts, more preferably 75-80 parts.

[0034] Unless otherwise specified, the amounts of the optional components mentioned above are all relative amounts based on the mass fraction of the aforementioned polymerized monomers, and the parts mentioned are all mass fractions. "Optional" means having or not having, for example, "optionally including" means containing or not containing.

[0035] The present invention also provides a method for preparing an aqueous acrylic copolymer microsphere suspension, the steps comprising:

[0036] 1) Mixing an emulsifier, a dispersant, and a stabilizer with water, and stirring at high speed to fully dissolve them to obtain a mixed solution;

[0037] 2) adding styrene, methyl methacrylate, butyl acrylate, methacrylic acid, hydroxyethyl (meth)acrylate, and 1,4-butanediol dimethacrylate to the mixed solution, stirring at high speed, and then ultrasonically dispersing to obtain a dispersion of the polymerized monomers;

[0038] 3) Stir the dispersion of the polymerization monomer and heat it to 60-70°C, for example, 62°C, 64°C, 66°C, 68°C, add an initiator thereto, react for 15-30min, for example, 18min, 21min, 24min, 27min, then heat it to 72-84°C, for example, 74°C, 76°C, 78°C, 80°C, react for 30-60min, for example, 35min, 40min, 45min, 50min, 55min, continue to heat it to 85-90°C, for example, 85°C, 87°C, 89°C, react for 4-6h, for example, 4.5h, 5.0h, 5.5h, to obtain an aqueous acrylate copolymer microsphere suspension.

[0039] In step 1) of the present invention, the high-speed stirring has no special requirements on the temperature, and can be operated at room temperature. The stirring speed is 1000-7000 rpm, for example, 3500 rpm, 4500 rpm, 5500 rpm, 6500 rpm, preferably 4000-5000 rpm, and the stirring time is 30-60 min, for example, 35 min, 45 min, 55 min, preferably 40-50 min.

[0040] In step 2) of the present invention, the high-speed stirring has no special requirements on the temperature, and can be operated at room temperature. The stirring speed is 1000-7000rpm, such as 3500rpm, 4500rpm, 5500rpm, 6500rpm, preferably 4000-5000rpmrpm, and the stirring time is 50-120min, such as 55min, 75min, 85min, 105min, preferably 60-80min;

[0041] The ultrasonic dispersion has no special requirement on temperature and can be operated at room temperature. The ultrasonic frequency is 10-20 KHz, such as 12 KHz, 14 KHz, 16 KHz, 18 KHz, preferably 15-20 KHz, and the time is 5-20 min, such as 7 min, 12 min, 17 min, preferably 10-15 min.

[0042] In step 3) of the present invention, the reaction is carried out under stirring conditions, and the stirring speed is 150-400 rpm, such as 180 rpm, 250 rpm, 350 rpm, 450 rpm, preferably 200-300 rpm.

[0043] The aqueous acrylate copolymer microsphere suspension of the present invention has the advantages of good compatibility with acrylic emulsion, high extinction efficiency, low light transmission loss of emulsion, etc., and can be applied to the fields of architectural coatings, wooden furniture, water-based inks, etc., and is particularly suitable for finishing coatings for interior and exterior walls of buildings, topcoats for wooden furniture, etc.

[0044] The present invention provides a highly light-transmitting self-matting topcoat, wherein the topcoat comprises the aqueous acrylate copolymer microsphere suspension of the present invention;

[0045] Preferably, based on the total mass of the topcoat as 100%, the amount of the aqueous acrylate copolymer microsphere suspension is 1-10%, for example 2%, 4%, 5%, 6%, 7%, 8%, 9%, preferably 3-8%, based on the solid mass of the microspheres therein.

[0046] The highly light-transmitting self-matting topcoat containing the aqueous acrylic copolymer microsphere suspension of the present invention can ensure that the coating has excellent matting performance, good light transmission performance, high abrasion resistance and high water resistance. The glossiness of the coating is less than 10 and the transmittance is higher than 90%.

[0047] In some specific embodiments, the highly transparent self-matting topcoat comprises the aqueous acrylate copolymer microsphere suspension and a film-forming emulsion;

[0048] The film-forming emulsion can be purchased from ordinary commercial sources, such as Wanhua Chemical Lacper 4501 / 4507, etc.; it can also be prepared by any feasible method known in the prior art, such as preparing it from polymerizable monomers through free radical emulsion polymerization.

[0049] Preferably, the present invention provides a film-forming emulsion, which is prepared by free radical emulsion polymerization of the following components in parts by mass:

[0050] Methyl methacrylate (MMA) 20.0-60.0 parts, for example 25.0 parts, 35.0 parts, 40.0 parts, 45.0 parts, 55.0 parts, preferably 30.0-50.0 parts;

[0051] Butyl acrylate (BA) 5.0-20.0 parts, such as 8.0 parts, 12.0 parts, 16.0 parts, 19.0 parts, preferably 10.0-15.0 parts;

[0052] Methacrylic acid (MAA) 0.5-5.0 parts, such as 0.8 parts, 1.3 parts, 2.0 parts, 3.0 parts, 4.0 parts, preferably 1.0-1.5 parts;

[0053] Emulsifier 0.1-0.8 parts, such as 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, preferably 0.3-0.5 parts;

[0054] 0.1-0.5 parts of buffer, such as 0.15 parts, 0.25 parts, 0.35 parts, 0.45 parts, preferably 0.2-0.3 parts;

[0055] Initiator 0.1-0.4 parts, such as 0.15 parts, 0.25 parts, 0.35 parts, preferably 0.2-0.3 parts;

[0056] Silane coupling agent 0.05-0.30 parts, such as 0.08 parts, 0.15 parts, 0.25 parts, preferably 0.1-0.2 parts;

[0057] 0.05-0.20 parts of post-treatment agent, for example 0.08 parts, 0.11 parts, 0.14 parts, 0.17 parts, preferably 0.10-0.15 parts;

[0058] Water 45-60 parts, such as 48 parts, 53 parts, 58 parts, preferably 50-55 parts.

[0059] Preferably, the emulsifier is selected from sodium dodecyl sulfate (SDS) and / or sodium dodecylbenzene sulfonate (SDBS);

[0060] The buffer is selected from sodium bicarbonate and / or ammonium bicarbonate;

[0061] The initiator is selected from ammonium persulfate and / or sodium persulfate;

[0062] The silane coupling agent is selected from vinyl trioxy silane and / or methacryloxypropyl trimethoxy silane;

[0063] The post-treatment agent is selected from tert-butyl hydroperoxide and / or isoascorbic acid.

[0064] Specifically, a method for preparing the film-forming emulsion comprises the following steps:

[0065] (1) dissolving a portion of the emulsifier in a portion of the water, and then adding methyl methacrylate, butyl acrylate, and methacrylic acid and mixing them evenly to obtain a monomer pre-emulsion;

[0066] (2) Mix the remaining water, remaining emulsifier and buffer, raise the temperature to 83-85° C., add part of the monomer pre-emulsion and part of the initiator, mix evenly, and then dropwise add the remaining monomer pre-emulsion and the remaining initiator simultaneously, with the dropping time of 180-240 min;

[0067] (3) After the addition is completed, keep the temperature for 15-30 minutes, then cool it to below 70°C, add the post-treatment agent at the same time, and then control the kettle temperature at 68-72°C to react for 60-90 minutes;

[0068] (4) Then the temperature is lowered to below 50° C., a neutralizing agent (such as 25% ammonia water) is added to adjust the pH to between 7 and 9, and the mixture is stirred for 10 to 20 minutes before being discharged to obtain a film-forming emulsion.

[0069] The amount of the emulsifier added in step (1) is 20-70% of the total mass of the emulsifier; the amount of water added is 15-50% of the total mass of the water;

[0070] In step (2), the mass ratio of the monomer pre-emulsion added twice is 1:20-35; the mass ratio of the initiator added twice is 1:1-2.

[0071] The film-forming emulsion of the present invention has a solid content of 40-50wt%, for example 42wt%, 44wt%, 46wt%, 48wt%, wherein the particle size of the solid particles is 70-140nm, for example 75nm, 85nm, 95nm, 105nm, 115nm, 125nm, 135nm, preferably 80-100nm.

[0072] The shear viscosity of the film-forming emulsion of the present invention is 200-2000 centipoise, preferably 700-1200 centipoise, and the glass transition temperature is 25-60°C.

[0073] In some specific embodiments, the raw materials for preparing the highly light-transmittant self-matting topcoat of the present invention may optionally include curing agents (e.g., 268), thickeners (e.g., 7160), leveling agents (e.g., 7260), film-forming aids (e.g., Texano), defoaming agents (e.g., DF-568) and other additives, which are conventionally selected in the art. The present invention has no special requirements for their types and amounts. When used, the raw material components in the formula are mixed.

[0074] Compared with the prior art, the present invention has the following beneficial effects:

[0075] (1) The present invention uses styrene, methyl methacrylate, n-butyl acrylate, methacrylic acid, and hydroxyethyl (meth)acrylate as polymerization monomers to prepare a water-based acrylic copolymer microsphere through a microsuspension polymerization reaction. The microsphere has the characteristics of swelling upon water absorption and shrinking upon water loss, so that the microsphere can shrink in volume during the process of becoming a coating component and curing to form a film, so that the surface of the coating has an uneven effect, thereby achieving a matte effect.

[0076] (2) The aqueous acrylate copolymer microspheres prepared by the present invention are used as the matting functional component, which can avoid coating defects caused by the difference between the traditional matting agent component and the film-forming component. Not only is the matting effect on the primer good, but the light transmittance of the coating is also good, which can ensure that the color of the bottom layer is not distorted, and at the same time has high abrasion resistance and high water resistance. DETAILED DESCRIPTION

[0077] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0078] 1. The sources of raw materials used in the embodiments of the present invention are shown in Table 1 below. Other raw materials are common commercially available unless otherwise specified:

[0079] Table 1

[0080] name purity supplier Methyl Methacrylate (MMA) 99.9％ Wanhua Chemical Methacrylic acid (MAA) 99.9％ Wanhua Chemical Hydroxyethyl acrylate (HEA) 99.9％ Wanhua Chemical n-Butyl acrylate (BA) 99.9％ Wanhua Chemical Styrene 99.9％ Wanhua Chemical 1,4-Butanediol dimethacrylate (BGDMA) 99.9％ Wanhua Chemical Sodium Lauryl Sulfate 99.5％ Solvay Sodium dodecylbenzenesulfonate (SDS) 99.5％ Solvay SE-10N 99.9％ EDICO Hydroxymethylpropyl cellulose 99.5％ Xilong Science Polyvinyl alcohol 99.5％ Xilong Science Ammonium Persulfate 99.5％ Xilong Science Benzoyl peroxide 99.5％ Xilong Science Sodium bicarbonate 99.5％ Xilong Science Sodium Nitrite 99.5％ Xilong Science Cetyl Alcohol 99.5％ Xilong Science

[0081] The preparation method of film-forming emulsion A is as follows: (1) 2 g SDS is dissolved in 95 g water, and then 250 g MMA, 150 g BA, and 15 g MAA are added and mixed uniformly to obtain a monomer pre-emulsion;

[0082] (2) 4 g SDS, 450 g water, and 0.9 g sodium bicarbonate were mixed, heated to 83-85° C., 22.6 g monomer pre-emulsion and 1.0 g ammonium persulfate were added, mixed evenly, and then the remaining monomer pre-emulsion and 1.0 g ammonium persulfate were added dropwise at the same time for 180 min;

[0083] (3) After the addition is complete, the reaction is carried out at a temperature of 30 minutes, then the temperature is lowered to 70°C, 0.9 g of tert-butyl hydroperoxide is added, and the kettle temperature is controlled at 68-72°C for 60 minutes;

[0084] (4) Then the temperature was lowered to 45° C., 25 wt % ammonia water was added to adjust the pH to 7-8, and the mixture was stirred for 10 min before discharging to obtain a film-forming emulsion A. The parameters are shown in Table 2.

[0085] Table 2 Parameters of film-forming emulsion A

[0086] Indicator name Film-forming emulsion A Appearance Translucent milky white liquid pH 7.8 Solid content (%) 42.9 Number average particle size (nm) 82 Proportional Dispersion Index (PDI) 0.039 Viscosity (centipoise, NDJ-1, 3# rotor 30 rpm) 784 Filter out residue(‰) 0.20 Mechanical stability (time for anilox roller to start discharging slag after continuous operation, h) 28 Drying speed of pure latex on the machine (60cm drying tunnel, 80℃, m) ≥200 Storage stability (time to start particle size change, days) ≥200 Measured Tg (DSC, heating rate: 5℃ / min,℃) 30.5 Measured minimum film forming temperature (MFT, ℃) ≤30

[0087] Film-forming emulsion B: Lacper 4501, Wanhua Chemical.

[0088] Film-forming emulsion C: Monkey Fairy 2004 emulsion, Monkey Fairy.

[0089] 2. Performance testing method adopted by the present invention:

[0090] The film resistance (water resistance, acid and alkali resistance) is tested according to the method in GBT23999-2009 "Water-based Wood Coatings for Interior Decoration and Renovation". A time of 24 hours is considered qualified, 48 hours or more is good, and 72 hours or more is excellent.

[0091] Test the light transmittance of the paint film according to the method in the national standard GB / T9761 "Paints and varnishes-Visual color comparison of paints";

[0092] The specular gloss at 60° is tested according to the method in GB / T9754 "Paints and varnishes - Determination of specular gloss at 20°, 60° and 85° of paint films without metallic pigments";

[0093] The abrasion resistance of the paint film is tested according to the method in the industry standard JC / T423 "Water-soluble Interior Wall Paint", where 60 times is considered qualified, 80 times or more is good, and 100 times or more is excellent.

[0094] Example 1

[0095] The aqueous acrylate copolymer microsphere suspension is prepared by:

[0096] Based on the total weight of the polymerized monomer components, the amount of methacrylic acid used was 3.2%, and the amount of hydroxyethyl acrylate monomer used was 16.1%.

[0097] 1) 0.1 g of emulsifier SDBS, 0.1 g of emulsifier SE-10N, 5 g of dispersant HPMC, 5 g of dispersant PVA, 0.1 g of stabilizer NaNO2, and 0.1 g of stabilizer CA were mixed with 725 g of water, and stirred at a high speed of 1000 rpm for 40 min to fully dissolve them to obtain a mixed solution;

[0098] 2) adding 100 g of styrene, 50 g of methyl methacrylate, 100 g of butyl acrylate, 10 g of methacrylic acid, 50 g of hydroxyethyl acrylate, and 0.1 g of 1,4-butanediol dimethacrylate to the mixed solution, stirring at a speed of 1000 rpm for 80 min, and then ultrasonically dispersing at a frequency of 15 KHz for 10 min to obtain a dispersion of the polymerized monomer;

[0099] 3) The dispersion of the polymerizable monomers was transferred to a polymerization kettle, stirred at 300 rpm and heated to 60° C., 0.6 g of initiator BPO was added, and the mixture was reacted for 15 min. The mixture was then heated to 75° C. and reacted for 30 min. The mixture was further heated to 85° C. and reacted for 5 h to obtain an aqueous acrylate copolymer microsphere suspension, which was a milky white liquid with a solid content of 31.0 wt %, a number average particle size (dZ) of 5 μm, and a dispersion index (PDI) of 0.27.

[0100] The steps for preparing a self-matting topcoat with high light transmittance are as follows:

[0101] 32.25 g of aqueous acrylate copolymer microsphere suspension (10 g of microsphere solid content) and 990 g of film-forming emulsion A were weighed separately and added into a reaction bottle, stirring was started, 10 g of curing agent 268 (added after dilution), 2 g of thickener 7160, 3 g of leveling agent 7260, 3 g of film-forming aid Texanol and 1.5 g of defoamer DF-568 were added and stirred at 300 rpm for 1 hour to obtain a topcoat, and its performance was tested. The results are shown in Table 3.

[0102] Example 2

[0103] Prepare an aqueous acrylate copolymer microsphere suspension by:

[0104] Based on the total weight of the polymerized monomer components, the amount of methacrylic acid used was 13.2%, and the amount of hydroxyethyl acrylate monomer used was 17.3%.

[0105] 1) 0.5 g of emulsifier SDBS, 0.5 g of emulsifier SE-10N, 10 g of dispersant HPMC, 10 g of dispersant PVA, 0.5 g of stabilizer NaNO2, and 0.5 g of stabilizer CA were mixed with 855 g of water, and stirred at a high speed of 4000 rpm for 40 min to fully dissolve them to obtain a mixed solution;

[0106] 2) adding 30 g of styrene, 30 g of methyl methacrylate, 60 g of butyl acrylate, 23 g of methacrylic acid, 30 g of hydroxyethyl acrylate, and 0.5 g of 1,4-butanediol dimethacrylate to the mixed solution, stirring at a speed of 3000 rpm for 80 min, and then ultrasonically dispersing at a frequency of 15 KHz for 10 min to obtain a dispersion of the polymerized monomers;

[0107] 3) The dispersion of the polymerizable monomers was transferred to a polymerization kettle, stirred at 400 rpm and heated to 60° C., then 1.0 g of initiator BPO was added, and the mixture was reacted for 15 min. The mixture was then heated to 75° C. and reacted for 30 min. The mixture was further heated to 85° C. and reacted for 5 h to obtain an aqueous acrylate copolymer microsphere suspension, which was a milky white liquid with a solid content of 17.4 wt %, a number average particle size (dZ) of 5 μm, and a dispersion index (PDI) of 0.16.

[0108] The steps for preparing a self-matting topcoat with high light transmittance are as follows:

[0109] 287.3 g of aqueous acrylate copolymer microsphere suspension (50 g of microsphere solid content) and 950 g of film-forming emulsion A were weighed separately and added into a reaction bottle, stirring was started, 10 g of curing agent 268 (added after dilution), 2 g of thickener 7160, 3 g of leveling agent 7260, 3 g of film-forming aid Texanol and 1.5 g of defoamer DF-568 were added and stirred at 300 rpm for 1 hour to obtain a topcoat, and its performance was tested. The results are shown in Table 3.

[0110] Example 3

[0111] Prepare an aqueous acrylate copolymer microsphere suspension by:

[0112] Based on the total weight of the polymerized monomer components, the amount of methacrylic acid used was 26.6%, and the amount of hydroxyethyl acrylate monomer used was 21.3%.

[0113] 1) Mix 1g of emulsifier SDBS, 1g of emulsifier SE-10N, 20g of dispersant HPMC, 20g of dispersant PVA, 1g of stabilizer NaNO2, and 1g of stabilizer CA with 730g of water, and stir at a high speed of 5000rpm for 60min to fully dissolve them to obtain a mixed solution;

[0114] 2) adding 35 g of styrene, 15 g of methyl methacrylate, 30.8 g of butyl acrylate, 41.8 g of methacrylic acid, 33.4 g of hydroxyethyl acrylate, and 1 g of 1,4-butanediol dimethacrylate to the mixed solution, stirring at a speed of 5000 rpm for 120 min, and then ultrasonically dispersing at a frequency of 15 KHz for 15 min to obtain a dispersion of the polymerized monomers;

[0115] 3) The dispersion of the polymerizable monomers was transferred to a polymerization kettle, stirred at 300 rpm and heated to 65° C., then 5 g of initiator BPO was added and reacted for 30 min. The mixture was then heated to 84° C. and reacted for 30 min. The mixture was further heated to 90° C. and reacted for 5 h to obtain an aqueous acrylate copolymer microsphere suspension, which was a milky white liquid with a solid content of 22 wt %, a number average particle size (dZ) of 4 μm, and a dispersion index (PDI) of 0.1.

[0116] The steps for preparing a self-matting topcoat with high light transmittance are as follows:

[0117] 227 g of aqueous acrylate copolymer microsphere suspension (50 g of microsphere solid content) and 950 g of film-forming emulsion A were weighed separately and added into a reaction bottle, stirring was started, 10 g of curing agent 268 (added after dilution), 2 g of thickener 7160, 3 g of leveling agent 7260, 3 g of film-forming aid Texanol and 1.5 g of defoamer DF-568 were added and stirred at 300 rpm for 1 hour to obtain a topcoat, and its performance was tested. The results are shown in Table 3.

[0118] Example 4

[0119] Prepare an aqueous acrylate copolymer microsphere suspension by:

[0120] Based on the total weight of the polymerized monomer components, the amount of methacrylic acid used was 36.1%, and the amount of hydroxyethyl acrylate monomer used was 6%.

[0121] 1) 1.0 g of emulsifier SDBS, 1.0 g of emulsifier SE-10N, 30 g of dispersant HPMC, 30 g of dispersant PVA, 1.0 g of stabilizer NaNO2, 1.0 g of stabilizer CA and 840 g of water were mixed, and stirred at a high speed of 5000 rpm for 40 min to fully dissolve them to obtain a mixed solution;

[0122] 2) adding 60 g of styrene, 5 g of methyl methacrylate, 30 g of butyl acrylate, 60 g of methacrylic acid, 10 g of hydroxyethyl methacrylate, and 1.0 g of 1,4-butanediol dimethacrylate to the mixed solution, stirring at a speed of 5000 rpm for 120 min, and then ultrasonically dispersing at a frequency of 15 KHz for 15 min to obtain a dispersion of the polymerized monomer;

[0123] 3) The dispersion of the polymerizable monomers was transferred to a polymerization kettle, stirred at 300 rpm and heated to 65° C., then 5.0 g of initiator BPO was added and reacted for 30 min. The mixture was then heated to 84° C. and reacted for 30 min. The mixture was further heated to 90° C. and reacted for 5 h to obtain an aqueous acrylate copolymer microsphere suspension, which was a milky white liquid with a solid content of 16.6 wt %, a number average particle size (dZ) of 5 μm, and a dispersion index (PDI) of 0.23.

[0124] The steps for preparing a self-matting topcoat with high light transmittance are as follows:

[0125] 481.9 g of aqueous acrylate copolymer microsphere suspension (80 g of microsphere solid content) and 920 g of Wanhua Chemical Lacper4501 film-forming emulsion B were weighed and added into a reaction bottle, stirring was started, 10 g of curing agent 268 (added after dilution), 2 g of thickener 7160, 3 g of leveling agent 7260, 3 g of film-forming aid Texanol and 1.5 g of defoamer DF-568 were added and stirred at 300 rpm for 1 hour to obtain a topcoat, and its performance was tested. The results are shown in Table 3.

[0126] Example 5

[0127] Prepare an aqueous acrylate copolymer microsphere suspension by:

[0128] Based on the total weight of the polymerized monomer components, the amount of methacrylic acid used was 27.9%, and the amount of hydroxyethyl acrylate monomer used was 1.4%.

[0129] 1) 3.0 g of emulsifier SDBS, 3.0 g of emulsifier SE-10N, 50 g of dispersant HPMC, 50 g of dispersant PVA, 2.0 g of stabilizer NaNO2, 2.0 g of stabilizer CA and 630 g of water were mixed, and stirred at a high speed of 3000 rpm for 40 min to fully dissolve them to obtain a mixed solution;

[0130] 2) adding 100 g of styrene, 50 g of methyl methacrylate, 100 g of butyl acrylate, 100 g of methacrylic acid, 5 g of hydroxyethyl acrylate, and 3.0 g of 1,4-butanediol dimethacrylate to the mixed solution, stirring at a speed of 3000 rpm for 80 min, and then ultrasonically dispersing at a frequency of 15 KHz for 10 min to obtain a dispersion of the polymerized monomers;

[0131] 3) The dispersion of the polymerizable monomers was transferred to a polymerization kettle, stirred at 200 rpm and heated to 70° C., 10 g of initiator BPO was added, and the mixture was reacted for 15 min. The mixture was then heated to 80° C. and reacted for 60 min. The mixture was further heated to 85° C. and reacted for 4 h to obtain an aqueous acrylate copolymer microsphere suspension, which was a milky white liquid with a solid content of 35.8 wt %, a number average particle size (dZ) of 5 μm, and a dispersion index (PDI) of 0.32.

[0132] The steps for preparing a self-matting topcoat with high light transmittance are as follows:

[0133] 279.3 g of aqueous acrylate copolymer microsphere suspension (100 g of microsphere solid content) and 900 g of Houxian 2004 film-forming emulsion C were weighed separately and added into a reaction bottle, stirring was started, 10 g of curing agent 268 (added after dilution), 2 g of thickener 7160, 3 g of leveling agent 7260, 3 g of film-forming aid Texanol and 1.5 g of defoamer DF-568 were added and stirred at 300 rpm for 1 hour to obtain a topcoat, and its performance was tested. The results are shown in Table 3.

[0134] Comparative Example 1

[0135] An aqueous acrylate copolymer microsphere suspension was prepared by referring to the method of Example 2, except that the raw material styrene monomer was not added. The obtained copolymer microsphere suspension was a milky white liquid with a solid content of 18wt%, a number average particle size (dZ) of 5μm, and a dispersion index (PDI) of 0.29.

[0136] Referring to the method of Example 2, the aqueous acrylate copolymer microsphere suspension was replaced by the copolymer microsphere suspension prepared in this comparative example to prepare a topcoat, and its performance was tested. The results are shown in Table 3.

[0137] Comparative Example 2

[0138] An aqueous acrylate copolymer microsphere suspension was prepared by referring to the method of Example 2, except that the raw material methyl methacrylate monomer was not added. The obtained copolymer microsphere suspension was a milky white liquid with a solid content of 12 wt %, a number average particle size (dZ) of 15 μm, and a dispersion index (PDI) of 0.56.

[0139] Referring to the method of Example 2, the aqueous acrylate copolymer microsphere suspension was replaced by the copolymer microsphere suspension prepared in this comparative example to prepare a topcoat, and its performance was tested. The results are shown in Table 3.

[0140] Comparative Example 3

[0141] An aqueous acrylate copolymer microsphere suspension was prepared by referring to the method of Example 2, except that the raw material hydroxyethyl acrylate monomer was not added. The obtained copolymer microsphere suspension was a milky white liquid with a solid content of 15wt%, a number average particle size (dZ) of 8μm, and a dispersion index (PDI) of 0.59.

[0142] Referring to the method of Example 2, the aqueous acrylate copolymer microsphere suspension was replaced by the copolymer microsphere suspension prepared in this comparative example to prepare a topcoat, and its performance was tested. The results are shown in Table 3.

[0143] Comparative Example 4

[0144] An aqueous acrylate copolymer microsphere suspension was prepared by referring to the method of Example 2, except that the hydroxyethyl acrylate monomer was replaced with an equal mass of hydroxybutyl acrylate to obtain a copolymer microsphere suspension, which was a milky white liquid with a solid content of 14 wt %, a number average particle size (dZ) of 9 μm, and a dispersion index (PDI) of 0.49.

[0145] Referring to the method of Example 2, the aqueous acrylate copolymer microsphere suspension was replaced by the copolymer microsphere suspension prepared in this comparative example to prepare a topcoat, and its performance was tested. The results are shown in Table 3.

[0146] Comparative Example 5

[0147] An aqueous acrylate copolymer microsphere suspension was prepared by referring to the method of Example 2, except that the stabilizer was removed in step 1. The obtained copolymer microsphere suspension was a milky white liquid with a solid content of 15 wt %, a number average particle size (dZ) of 18 μm, and a dispersion index (PDI) of 0.85.

[0148] Referring to the method of Example 2, the aqueous acrylate copolymer microsphere suspension was replaced by the copolymer microsphere suspension prepared in this comparative example to prepare a topcoat, and its performance was tested. The results are shown in Table 3.

[0149] Table 3 Test results of high light transmittance self-matting topcoat coating performance of embodiments and comparative examples

[0150]

[0151] As can be seen from Table 3, the water-based acrylic emulsion type topcoat varnish prepared by the present invention not only has a good protective effect on the primer, but also has good matting performance and light transmission performance, and the balance between matting and light transmission can be achieved by adding microspheres that expand when absorbing water and shrink when losing water.

Claims

1. An aqueous acrylic copolymer microsphere suspension, characterized in that: The polymerizable monomer components including the following parts by weight are prepared by microsuspension polymerization: The aqueous acrylate copolymer microsphere suspension, wherein the microsphere component has a particle size of 2-10 μm; The raw materials for preparing the aqueous acrylate copolymer microsphere suspension include a stabilizer, and the stabilizer is selected from any one of sodium nitrite, hexadecanol, and hexadecane, or a combination of at least two of them.

2. The aqueous acrylate copolymer microsphere suspension according to claim 1, characterized in that: The polymerizable monomer components including the following parts by weight are prepared by microsuspension polymerization:

3. The aqueous acrylate copolymer microsphere suspension according to claim 1, characterized in that: The (meth) hydroxyethyl acrylate monomer is selected from any one of hydroxyethyl acrylate and hydroxyethyl methacrylate or a combination of both; and / or Based on the total mass of the polymerized monomer components, the amount of methacrylic acid is 13-36.5%; Based on the total weight of the polymerized monomer components, the amount of hydroxyethyl (meth)acrylate is 5-30%; and / or The aqueous acrylate copolymer microsphere suspension, wherein the microsphere component has a particle size of 4-7 μm; The aqueous acrylic ester copolymer microsphere suspension has a solid content of 15-36 wt %.

4. The aqueous acrylate copolymer microsphere suspension according to claim 3, characterized in that: The amount of methacrylic acid used is 20-25% based on the total weight of the polymerized monomer components.

5. The aqueous acrylate copolymer microsphere suspension according to claim 3, characterized in that: Based on the total weight of the polymerized monomer components, the amount of the hydroxyethyl (meth)acrylate is 10-20%.

6. The aqueous acrylate copolymer microsphere suspension according to claim 3, characterized in that: The aqueous acrylic ester copolymer microsphere suspension has a solid content of 20-25 wt %.

7. The aqueous acrylate copolymer microsphere suspension according to claim 1, characterized in that: The stabilizer is used in an amount of 0.01-0.4 parts.

8. The aqueous acrylate copolymer microsphere suspension according to claim 7, characterized in that: The stabilizer is used in an amount of 0.05-0.2 parts.

9. The aqueous acrylate copolymer microsphere suspension according to claim 1, characterized in that: The aqueous acrylate copolymer microsphere suspension is obtained by a microsuspension polymerization method; The raw materials for preparing the aqueous acrylate copolymer microsphere suspension optionally include an emulsifier, an initiator, a dispersant, and water; The emulsifier is selected from any one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and allyloxy nonylphenol polyoxyethylene ether ammonium sulfate, or a combination of at least two thereof; The initiator is selected from dibenzoyl peroxide and / or azobisisobutyronitrile; The dispersant is selected from hydroxymethylpropyl cellulose and / or polyvinyl alcohol.

10. The aqueous acrylate copolymer microsphere suspension according to claim 9, characterized in that: The emulsifier is used in an amount of 0.01-0.6 parts.

11. The aqueous acrylate copolymer microsphere suspension according to claim 10, characterized in that: The emulsifier is used in an amount of 0.05-0.2 parts.

12. The aqueous acrylate copolymer microsphere suspension according to claim 9, characterized in that: The dosage of the initiator is 0.05-1 part.

13. The aqueous acrylate copolymer microsphere suspension according to claim 12, characterized in that: The initiator is used in an amount of 0.1-0.5 parts.

14. The aqueous acrylate copolymer microsphere suspension according to claim 9, characterized in that: The dispersant is used in an amount of 0.5-10 parts.

15. The aqueous acrylate copolymer microsphere suspension according to claim 14, characterized in that: The dispersant is used in an amount of 1.0-6.0 parts.

16. The aqueous acrylate copolymer microsphere suspension according to claim 9, characterized in that: The water usage is 63-86 parts.

17. The aqueous acrylate copolymer microsphere suspension according to claim 16, characterized in that: The water usage is 75-80 parts.

18. A method for preparing the aqueous acrylate copolymer microsphere suspension according to any one of claims 1 to 17, characterized in that the steps include: 1) Mixing an emulsifier, a dispersant, and a stabilizer with water, and stirring at high speed to fully dissolve them to obtain a mixed solution; 2) adding styrene, methyl methacrylate, butyl acrylate, methacrylic acid, hydroxyethyl (meth)acrylate, and 1,4-butanediol dimethacrylate to the mixed solution, stirring at high speed, and then ultrasonically dispersing to obtain a dispersion of the polymerized monomers; 3) Stirring the dispersion of the polymerization monomer and heating it to 60-70° C., adding an initiator thereto, reacting for 15-30 minutes, then heating it to 72-84° C. and reacting for 30-60 minutes, and then heating it to 85-90° C. and reacting for 4-6 hours to obtain an aqueous acrylate copolymer microsphere suspension.

19. The preparation method according to claim 18, characterized in that: In step 1), the high-speed stirring has a stirring speed of 1000-7000 rpm and a stirring time of 30-60 min; In step 2), the high-speed stirring has a stirring speed of 1000-7000 rpm and a stirring time of 50-120 min; The ultrasonic dispersion has an ultrasonic frequency of 10-20 KHz and a time of 5-20 min; In step 3), the reaction is carried out under stirring conditions, and the stirring speed is 150-400 rpm.

20. The preparation method according to claim 19, characterized in that: In step 1), the high-speed stirring has a stirring speed of 4000-5000 rpm and a stirring time of 40-50 min.

21. The preparation method according to claim 19, characterized in that: In step 2), the high-speed stirring has a stirring speed of 4000-5000 rpm and a stirring time of 60-80 min.

22. The preparation method according to claim 19, characterized in that: In step 2), the ultrasonic dispersion has an ultrasonic frequency of 15-20 KHz and a time of 10-15 min.

23. The preparation method according to claim 19, characterized in that: In step 3), the reaction is carried out under stirring conditions, and the stirring speed is 200-300 rpm.

24. Use of the aqueous acrylate copolymer microsphere suspension according to any one of claims 1 to 17 or the aqueous acrylate copolymer microsphere suspension prepared by the method according to any one of claims 18 to 23 in the fields of architectural coatings, wooden furniture, and water-based inks.

25. The use according to claim 24, characterized in that Suitable for finishing paint on interior and exterior walls of buildings and topcoat on wooden furniture.

26. A highly transparent self-matting topcoat, characterized in that: The topcoat comprises the aqueous acrylate copolymer microsphere suspension according to any one of claims 1 to 17 or the aqueous acrylate copolymer microsphere suspension prepared by the method according to any one of claims 18 to 23.

27. The highly transparent self-matting topcoat according to claim 26, characterized in that: Based on the total mass of the topcoat being 100%, the amount of the aqueous acrylate copolymer microsphere suspension is 1-10%, based on the solid mass of the microspheres therein.

28. The highly transparent self-matting topcoat according to claim 27, characterized in that: The amount of the aqueous acrylic copolymer microsphere suspension is 3-8%, based on the solid mass of the microspheres therein.

29. The highly transparent self-matting topcoat according to claim 26, characterized in that: It includes the aqueous acrylate copolymer microsphere suspension and film-forming emulsion; The film-forming emulsion is selected from one of Wanhua Chemical Lacper 4501 and 4507, or is prepared from polymerizable monomers through free radical emulsion polymerization.

30. The highly transparent self-matting topcoat according to claim 29, characterized in that: The film-forming emulsion is prepared by free radical emulsion polymerization of the following components in parts by mass:

31. The highly transparent self-matting topcoat according to claim 30, characterized in that: The film-forming emulsion is prepared by free radical emulsion polymerization of the following components in parts by mass:

32. The highly transparent self-matting topcoat according to claim 30, characterized in that: The emulsifier is selected from sodium dodecyl sulfate and / or sodium dodecylbenzene sulfonate; The buffer is selected from sodium bicarbonate and / or ammonium bicarbonate; The initiator is selected from ammonium persulfate and / or sodium persulfate; The silane coupling agent is selected from vinyl trioxy silane and / or methacryloxypropyl trimethoxy silane; The post-treatment agent is selected from tert-butyl hydroperoxide and / or isoascorbic acid.

33. The highly transparent self-matting topcoat according to claim 30, characterized in that: The film-forming emulsion has a solid content of 40-50 wt %, wherein the particle size of the solid particles is 70-140 nm; The shear viscosity of the film-forming emulsion is 200-2000 centipoise, and the glass transition temperature is 25-60°C.

34. The highly transparent self-matting topcoat according to claim 33, characterized in that: The particle size of the solid particles is 80-100 nm.

35. The highly transparent self-matting topcoat according to claim 33, characterized in that: The shear viscosity of the film-forming emulsion is 700-1200 centipoise.

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