Acrylate emulsion and preparation method thereof

Abstract

The invention provides an acrylate emulsion and a preparation method thereof, the acrylate emulsion comprises the following raw materials by mass: 40-168 parts of an acrylate monomer, 0.1-10 parts of an internal plasticizing monomer, 0.01-5 parts of an emulsifier, 0.01-2 parts of an initiator, and 0.1-38 parts of a blue light absorption aid; the acrylate monomer is prepared from 25 to 85 parts of monovinyl aromatic monomer, 15 to 75 parts of alkyl (methyl) acrylate and 0.01 to 8 parts of alpha, beta-monoethylenically unsaturated C2-C16 monocarboxylic acid or dicarboxylic acid; the internal plasticizing monomer comprises dibutyl maleate; and the pH value of the acrylate emulsion is 6-9. According to the invention, the specific acrylate monomer, the internal plasticizing monomer and the blue light absorption aid are reasonably compounded, and the components can play a synergistic role, so that the acrylate emulsion has continuous blue light absorption efficiency and good film-forming characteristic and mechanical property.

Description

Technical Field

[0001] The invention belongs to the technical field of resin and chemical synthesis, and specifically relates to an acrylic ester emulsion and a preparation method thereof. Background Art

[0002] Water-based acrylic emulsions and coating compositions thereof are used in a variety of scenarios. When such coating compositions are used as wall coatings, they are not only required to have a decorative function on the wall, but also to have one or more additional functions. For example, most families have begun to use LED lights for home decoration, which will also bring about "blue light pollution" that is ignored by people. Blue light will produce very high energy and can penetrate the lens of the eye directly to the retina. Blue light irradiating the retina will produce free radicals, which will cause the epithelial cells of the retinal pigment to die. The death of epithelial cells leads to macular degeneration and visual impairment, and these injuries are irreversible. However, conventional coatings do not have the function of absorbing blue light. Instead, they will act as a reflective medium to diffuse light waves in all directions. Therefore, preparing an emulsion and coating that can absorb blue light is a technical problem that technicians in this field urgently need to solve. Summary of the invention

[0003] The object of the present invention is to provide an acrylate emulsion and a preparation method thereof. The acrylate emulsion can continuously absorb blue light and has good film-forming performance.

[0004] According to one aspect of the present invention, an acrylate emulsion is provided. Calculated by weight, the raw materials of the acrylate emulsion include 40 to 168 parts of acrylate monomers, 0.1 to 10 parts of internal plasticizer monomers, 0.01 to 5 parts of emulsifiers, 0.01 to 2 parts of initiators, and 0.1 to 38 parts of blue light absorption aids; the acrylate monomers include monovinyl aromatic monomers, (meth) alkyl acrylates, and α, β-monoethylenically unsaturated C2-C16 monocarboxylic acids or dicarboxylic acids, wherein the mass ratio of the monovinyl aromatic monomers, (meth) alkyl acrylates, and α, β-monoethylenically unsaturated C2-C16 monocarboxylic acids or dicarboxylic acids is (25 to 85): (15 to 75): (0.01 to 8); the internal plasticizer monomer includes dibutyl maleate; and the pH of the acrylate emulsion is 6 to 9.

[0005] The present invention adjusts the formula of the acrylic emulsion so that the specific acrylic monomer, the internal plasticizer monomer and the blue light absorbing auxiliary agent have good compatibility and can be coordinated to reduce the film-forming temperature of the acrylic emulsion and improve the cohesive force of the acrylic emulsion, so that the acrylic emulsion has good film-forming characteristics, wrapping ability and mechanical properties, and is conducive to controlling the particle size and particle size distribution uniformity of the emulsion particles in the acrylic emulsion, promoting the blue light absorbing auxiliary agent to be stably and uniformly dispersed in the emulsion particles, so that the blue light absorbing auxiliary agent can continuously exert its blue light absorbing function, and at the same time, promote the acrylic emulsion to form a dense and uniform emulsion film; moreover, the above formula can increase the addition amount of the blue light absorbing auxiliary agent under the premise of ensuring the dispersibility and stability of the acrylic emulsion, so that the blue light absorption efficiency of the acrylic emulsion is further improved.

[0006] In summary, the present invention reasonably compounds specific acrylate monomers, internal plasticizer monomers and blue light absorbing additives, and each component can play a synergistic role, so that the acrylate emulsion has continuous blue light absorption efficiency and good film-forming properties and mechanical properties.

[0007] Preferably, the monovinyl aromatic monomer comprises styrene.

[0008] Preferably, the alkyl (meth)acrylate comprises at least one of butyl acrylate, sec-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, and isooctyl acrylate;

[0009] Preferably, the α,β-monoethylenically unsaturated C2-C 16 The monocarboxylic acid or dicarboxylic acid includes at least one of acrylic acid, methacrylic acid, β-acryloxypropionic acid, itaconic acid, fumaric acid, maleic acid, and caprolactone grafted carboxylic acid.

[0010] Preferably, the raw materials of the acrylic emulsion further include a stabilizer, wherein the stabilizer includes at least one of sodium vinyl sulfonate, sodium allyl ether hydroxypropyl sulfonate, sodium 2-acrylamido-2-methylpropane sulfonate, and a phosphate monoester stabilizer.

[0011] Preferably, the initiator solution comprises an initiator and water, wherein the initiator comprises at least one of ammonium persulfate, sodium persulfate and potassium persulfate.

[0012] Preferably, the emulsion comprises an emulsifier, a buffer and water, wherein the buffer comprises at least one of sodium bicarbonate, sodium bisulfite, potassium bicarbonate and potassium bisulfite.

[0013] Preferably, the blue light absorbing aid comprises an inorganic component and an organic component, the inorganic component comprises TiO2, and the organic component comprises at least one of benzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 4-hydroxybenzophenone, benzotriazole, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, and 2-(2'-hydroxy-3',5'-dipentylphenyl)benzotriazole. The above-mentioned blue light absorbing aid has a wide blue light absorption wavelength, and good stability and durability.

[0014] Preferably, the emulsifier includes branched alkyl alcohol polyoxyethylene ether phosphate monoester. Since the dispersibility of the blue light absorbing auxiliary agent is poor, and the inorganic component TiO2 in the above blue light absorbing auxiliary agent is easy to agglomerate, therefore, by adopting a specific emulsifier, the emulsifier molecule contains polyoxyethylene ether groups and phosphate monoester groups, the polyoxyethylene ether groups and phosphate monoester groups have high stability, and have good emulsification, dispersion and wetting properties, can promote the particles to be evenly dispersed in the emulsion, prevent the droplets from agglomerating, improve the stability of the acrylic emulsion, and promote it to form a stable and firm emulsified film. In addition, the emulsifier can further improve the adhesion of the coating thus prepared.

[0015] Preferably, the raw materials of the acrylic emulsion also include a dispersant, and the dispersant includes a sodium polycarboxylate. Since the introduction of a blue light absorbing agent in the polymerization process easily causes flocculation of the emulsion, the blue light absorbing agent is introduced into the reaction system in the form of a dispersion by using a sodium polycarboxylate as a dispersant. Since the sodium polycarboxylate has good dispersibility for the blue light absorbing agent, it can promote the uniform dispersion of the blue light absorbing agent, thereby further improving the dispersibility of the blue light absorbing agent and the blue light absorption efficiency of the acrylic emulsion while ensuring the stability of the emulsion.

[0016] According to another aspect of the present invention, a coating is provided, comprising the above-mentioned acrylic emulsion. The coating provided by the present invention has excellent blue light absorption efficiency and continuous blue light absorption capacity, protects indoor people from continuous blue light damage to the eyes, and has good adhesion and mechanical properties.

[0017] According to another aspect of the present invention, a method for preparing an acrylic emulsion is provided, comprising the following operations: S1. mixing a blue light absorbing aid, an acrylic ester monomer, an emulsifier and water to prepare a pre-emulsion; S2. adding a portion of the pre-emulsion and an initiator solution to the emulsion at 85 to 90° C. to obtain a seed emulsion; then adding a portion of the pre-emulsion and the initiator solution to the seed emulsion, and then adding an internal plasticizing monomer to the mixed solution obtained; S3. adding the remaining pre-emulsion and the initiator solution to the mixed solution obtained after S2 is completed and keeping the mixture at 85 to 90° C. to obtain a first intermediate solution; then adding a blue light absorbing aid to the first intermediate solution to obtain a second intermediate solution; S4. adjusting the pH of the second intermediate solution to 6 to 9 to obtain a third intermediate solution, and then adding a blue light absorbing aid to the third intermediate solution to prepare an acrylic emulsion.

[0018] The present invention adopts a seed emulsion polymerization method, which is conducive to preparing an acrylic emulsion with controllable particle size and uniform distribution; based on this, by further controlling the feeding time of the blue light absorbing auxiliary agent, the blue light absorbing auxiliary agent is introduced into the system in the pre-emulsification stage, the emulsion polymerization stage, and the post-treatment stage, respectively. The three stages can make the blue light absorbing auxiliary agent fully dispersed in the inner side and middle of the emulsion particles and the interface between the emulsion particles and the aqueous phase, so that the blue light absorbing auxiliary agent can be evenly distributed in the emulsion and continuously exert its blue light absorbing function, so that the acrylic emulsion prepared thereby has excellent blue light absorbing ability and continuous blue light absorbing effect. And the preparation method can increase the addition amount of the blue light absorbing auxiliary agent under the premise of ensuring the dispersibility and stability of the emulsion, so that the blue light absorption efficiency of the acrylic emulsion is further improved.

[0019] Among them, in the pre-emulsification stage, the blue light absorbing aid is pre-emulsified together with the acrylic ester monomer, emulsifier and water, which is conducive to promoting the distribution of the blue light absorbing aid in the interior of the emulsion particles; then, in the emulsion polymerization stage, the blue light absorbing aid is introduced into the reaction system, which is conducive to making the blue light absorbing aid evenly distributed in the middle area of ​​the emulsion particles (because the blue light absorbing aid is easy to deposit on the inner side of the emulsion particles during the polymerization reaction, therefore, after the remaining pre-emulsion liquid is polymerized, the blue light absorbing aid is introduced into the system for the second time, which is conducive to making the blue light absorbing aid evenly distributed in the middle area of ​​the emulsion particles); then, in the post-treatment stage, the pH value of the system is adjusted to ensure the stability of the emulsion. The blue light absorbing aid is introduced into the system after the pH is adjusted. Under the premise of ensuring the dispersibility and stability of the acrylic ester emulsion, the content of the blue light absorbing aid in the emulsion can be further increased, and the blue light absorbing aid is distributed at the interface between the emulsion particles and the water phase, thereby improving the blue light absorption efficiency of the acrylic ester emulsion.

[0020] Preferably, in S3, the blue light absorbing aid is added in the form of a dispersion, the dispersion comprises the blue light absorbing aid and a dispersant, the dispersant comprises sodium polycarboxylate, and the mass ratio of the dispersant to the blue light absorbing aid is 1:(1.5-2.5).

[0021] Preferably, the amount of the blue light absorbing aid is determined according to the mass of the acrylate monomer in the pre-emulsion: the mass of the blue light absorbing aid in S1: the mass of the dispersion in S3: the mass of the blue light absorbing aid in S4 = (50-168): (0.1-4): (1-38): (2-10). Since the introduction of the blue light absorbing aid may cause the emulsion to stratify, precipitate and the like, by accurately controlling the amount of the blue light absorbing aid in S1, S2 and S3, the blue light absorbing aid can be evenly dispersed in the emulsion while ensuring the stability of the emulsion, thereby further improving the blue light absorbing effect and continuous blue light absorbing capacity of the emulsion, and effectively avoiding the problem of decreased stability of the emulsion, deterioration of the blue light absorbing effect and continuous blue light absorbing capacity caused by adding more blue light absorbing aid.

[0022] Preferably, the feeding amount of the pre-emulsion in S2 is 60-95wt% of the total amount of the pre-emulsion used in the preparation method; the mass of the internal plasticizing monomer: the total mass of the acrylic acid ester monomer in the pre-emulsion used in the preparation method = (0.1-10): (40-168). By introducing the internal plasticizing monomer in the process of preparing the acrylic acid ester emulsion and accurately controlling the feeding time of the internal plasticizing monomer, the internal plasticizing monomer is added after the polymerization reaction occurs to a certain extent, which is conducive to controlling the polymerization reaction rate and ensuring that the polymerization reaction proceeds smoothly. At the same time, it can ensure that the internal plasticizing monomer fully participates in the polymerization reaction and is evenly distributed in the polymerization product, so that the plasticity and stability of the polymerization product are improved, avoiding the problem that the internal plasticizing monomer is added late so that more unreacted internal plasticizing monomer remains in the product, reducing its effective utilization rate, or the problem that the internal plasticizing monomer is added early so that the local concentration of the monomer is high, resulting in uncontrollable polymerization rate and uneven molecular weight distribution of the polymerization product.

[0023] Preferably, the internal plasticizing monomer includes dibutyl maleate. As an internal plasticizing monomer, dibutyl maleate can reduce the film-forming temperature of the emulsion, improve the cohesive force of the emulsion, and has good compatibility with the acrylate monomer. Therefore, by introducing dibutyl maleate into the emulsion, it is beneficial to ensure the stability of the emulsion while making it have good flexibility and tensile strength, so that the film-forming performance, mechanical properties and adhesion of the coating prepared thereby are further improved.

[0024] Preferably, after S2 is completed, it also includes: adding a redox initiator to the second reaction liquid at 55-80°C and keeping the temperature. By adding an appropriate amount of redox initiator in the late stage of the polymerization reaction, on the one hand, the redox initiator can generate free radicals, which can further promote the monomers that have not completely reacted to continue to participate in the polymerization, thereby improving the conversion rate of the monomers, reducing the residual amount of monomers in the emulsion, and improving the quality and stability of the emulsion; on the other hand, it can control the rate of the polymerization reaction, regulate the degree of polymerization and molecular weight distribution of the polymerization product, promote the uniform dispersion of the blue light absorbing additive and the emulsion particles, and improve the continuous blue light absorption capacity of the emulsion.

[0025] Preferably, the redox initiator comprises tert-butyl hydroperoxide and sodium bisulfite, wherein the mass ratio of tert-butyl hydroperoxide to sodium bisulfite is (1.2-1.3):1.

[0026] According to another aspect of the present invention, an acrylic emulsion is provided, which is prepared by the above-mentioned acrylic emulsion preparation method. The acrylic emulsion provided by the present invention has excellent blue light absorption efficiency, continuous blue light absorption ability, good film-forming properties and mechanical properties, and can protect indoor people from continuous blue light damage to the eyes. The acrylic emulsion does not contain volatile organic compounds (VOCs) and is more environmentally friendly.

[0027] According to another aspect of the present invention, there is provided a coating comprising the above-mentioned acrylic emulsion. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] Example 1

[0030] This embodiment provides an acrylic emulsion, and the preparation method thereof comprises the following operations:

[0031] S1. At room temperature and pressure, add 0.1g of emulsifier RS-610 (the main active ingredient of RS-610 is branched alkyl alcohol polyoxyethylene ether phosphate monoester), 0.1g of stabilizer sodium allyl ether hydroxypropyl sulfonate, and 15g of deionized water to a pre-emulsification tank with a monomer metering tank and a stirrer. After fully stirring and dissolving, add 52g of acrylate monomer (acrylate monomer includes 30g of styrene, 20g of n-butyl acrylate, 1g of methacrylic acid, and 1g of acrylic acid) and 0.5g of blue light absorption auxiliary 2-(2'-hydroxy-3.5'-dipentylphenyl)benzotriazole in sequence, stir well for 30 minutes, and prepare a pre-emulsion for standby use.

[0032] S2.

[0033] Prepare emulsion: add emulsifier and deionized water to a polymerization kettle equipped with a stirrer, a condenser, a constant flow pump feeding device, and a constant flow dripping metering device, stir thoroughly to dissolve, heat to the temperature in the polymerization kettle to 80°C, obtain emulsion, and set aside.

[0034] Preparation of initiator solution: At room temperature and pressure, add 0.01 g of ammonium persulfate and 10 g of deionized water to an initiator tank equipped with a stirrer and a constant-current dripping device, and stir until completely dissolved to obtain an initiator solution for later use.

[0035] When the temperature in the polymerization reactor reaches 86°C, add part of the pre-emulsion and the initiator solution to the emulsion (the amount of the pre-emulsion is 1wt% of the total amount of the pre-emulsion, and the amount of the initiator solution is 0.1wt% of the total amount of the initiator solution), and react for 20 minutes under stirring to obtain a seed emulsion;

[0036] After the seed emulsion is formed, the pre-emulsion and the initiator solution are synchronously added to the seed emulsion for the second time through the constant flow pump feeding device and the constant flow dripping metering device. When the remaining amount of the pre-emulsion is 40wt% of the total amount of the pre-emulsion (i.e., the feeding amount of the pre-emulsion in S2 is 60wt% of the total amount of the pre-emulsion adopted in the preparation method), the dripping is stopped, and then 0.05g of internal plasticizing monomer dibutyl maleate (DBM) is added to the mixed solution thus obtained and stirred evenly, wherein the mass of the internal plasticizing monomer DBM: the total mass of the acrylate monomer in the pre-emulsion adopted in the preparation method=0.05:52.

[0037] S3. Continue to dropwise add the remaining pre-emulsion and the initiator solution to the mixed solution obtained after S2 is completed, the total time of dropping the pre-emulsion is controlled within 120 minutes, and ensure that the initiator solution is added 30 minutes later than the pre-emulsion, and then keep warm at 86°C for 60 minutes to obtain a first intermediate solution; then dropwise add 1g of the dispersion (the dispersion includes 0.67g of a blue light absorbing aid 2-(2'-hydroxy-3.5'-dipentylphenyl)benzotriazole and 0.33g of a dispersant polycarboxylate sodium salt) to the first intermediate solution, and the dropping time is controlled within 10 minutes;

[0038] S4. Control the temperature in the polymerization kettle at 80°C, keep it warm for 15 minutes, then cool it to 65°C, and simultaneously add double drops of redox initiator (the redox initiator consists of an aqueous solution containing 0.012g of tert-butyl hydroperoxide and an aqueous solution containing 0.01g of FF6M), the addition time is 40 minutes, keep it warm for 20 minutes, then cool it to 40°C, adjust the pH to 8 with 5% KOH aqueous solution to obtain a third intermediate solution, and then add 2g of blue light absorption auxiliary agent 2-(2'-hydroxy-3.5'-dipentylphenyl)benzotriazole to the third intermediate solution, followed by adding 0.03g of defoamer and 0.4g of quick-kill bactericide, and filter the material with a 250-mesh filter to obtain an acrylic emulsion.

[0039] Example 2

[0040] This embodiment provides an acrylic emulsion, and the preparation method thereof comprises the following operations:

[0041] S1. At room temperature and pressure, add 1g of emulsifier RS-610, 1g of stabilizer sodium allyl ether hydroxypropyl sulfonate and 50g of deionized water to a pre-emulsification tank with a monomer metering tank and a stirrer. After fully stirring and dissolving, add 99g of acrylate monomer (55g of styrene, 40g of n-butyl acrylate, 2g of methacrylic acid, 2g of acrylic acid) and 0.5g of blue light absorption aid 4-hydroxybenzophenone in sequence, stir well for 30 minutes, and prepare a pre-emulsion for standby use.

[0042] S2.

[0043] Prepare emulsion: add emulsifier, buffer sodium bicarbonate and deionized water to a polymerization kettle equipped with a stirrer, condenser, constant flow pump feeding device and constant flow dripping metering device, stir thoroughly to dissolve, heat to the temperature in the polymerization kettle to 80°C, and obtain emulsion for use.

[0044] Preparation of initiator solution: at room temperature and pressure, add 1 g of ammonium persulfate and 20 g of deionized water to an initiator tank equipped with a stirrer and a constant-current dripping device, and stir until completely dissolved to obtain an initiator solution for later use.

[0045] When the temperature in the polymerization kettle reaches 88°C, add part of the pre-emulsion and the initiator solution to the emulsion (the amount of the pre-emulsion is 5wt% of the total amount of the pre-emulsion, and the amount of the initiator solution is 1wt% of the total amount of the initiator solution), and react for 20 minutes under stirring to obtain a seed emulsion;

[0046] After the seed emulsion is formed, the pre-emulsion and the initiator solution are added to the seed emulsion for the second time synchronously through the constant flow pump feeding device and the constant flow dripping metering device. When the remaining amount of the pre-emulsion is 20wt% of the total amount of the pre-emulsion (that is, the amount of the pre-emulsion in S2 is 80wt% of the total amount of the pre-emulsion used in the preparation method), the dripping is stopped, and then 1.5g of internal plasticizing monomer dibutyl maleate (DBM) is added to the resulting mixed solution at one time and stirred evenly, wherein the mass of the internal plasticizing monomer DBM: the total mass of the acrylate monomer in the pre-emulsion used in the preparation method = 1.5:99. .

[0047] S3. Continue to dropwise add the remaining pre-emulsion and the initiator solution to the mixed solution obtained after S2 is completed, the total time of dropping the pre-emulsion is controlled within 120 minutes, and ensure that the initiator solution is added 30 minutes later than the pre-emulsion, and then keep warm at 88°C for 60 minutes to obtain a first intermediate solution; then dropwise add 10g of the dispersion (the dispersion includes 6.7g of blue light absorbing aid 4-hydroxybenzophenone and 3.3g of dispersant polycarboxylate sodium salt) to the first intermediate solution, and the dropping time is controlled within 10 minutes;

[0048] S4. Control the temperature in the polymerization kettle at 80°C, keep it warm for 15 minutes, then cool it to 60°C, and simultaneously add double drops of redox initiator (the redox initiator consists of an aqueous solution containing 1.2g of tert-butyl hydroperoxide and an aqueous solution containing 1g of FF6M), the addition time is 50 minutes, keep it warm for 40 minutes, then cool it to 40°C, adjust the pH to 8 with a 5% KOH aqueous solution to obtain a third intermediate solution, and then add 8g of blue light absorption auxiliary agent 4-hydroxybenzophenone to the third intermediate solution, followed by adding 0.03g of defoamer and 0.4g of quick-kill bactericide, and filter the material with a 250-mesh filter to obtain an acrylic emulsion.

[0049] Example 3

[0050] This embodiment provides an acrylic emulsion, and the preparation method thereof comprises the following operations:

[0051] S1. At room temperature and pressure, add 5g of emulsifier RS-610, 2g of co-stabilizer sodium allyl ether hydroxypropyl sulfonate and 70g of deionized water to a pre-emulsification tank with a monomer metering tank and a stirrer. After fully stirring and dissolving, add 145g of acrylate monomer (75g of styrene, 65g of n-butyl acrylate, 3g of methacrylic acid, 2g of acrylic acid) and 2g of blue light absorbing auxiliary benzophenone in sequence, stir well for 30 minutes, and prepare a pre-emulsion for standby use.

[0052] S2.

[0053] Prepare emulsion: add emulsifier, buffer sodium bicarbonate and deionized water to a polymerization kettle equipped with a stirrer, condenser, constant flow pump feeding device and constant flow dripping metering device, stir well to dissolve, heat to the temperature in the polymerization kettle to 95°C, obtain emulsion and set aside.

[0054] Preparation of initiator solution: at room temperature and pressure, add 2 g of ammonium persulfate and 35 g of deionized water into an initiator tank equipped with a stirrer and a constant-current dripping device, and stir until completely dissolved to obtain an initiator solution for later use.

[0055] When the temperature in the polymerization kettle reaches 90° C., add part of the pre-emulsion and the initiator solution to the emulsion (the amount of the pre-emulsion is 50wt% of the total amount of the pre-emulsion, and the amount of the initiator solution is 10wt% of the total amount of the initiator solution), and react for 20 minutes under stirring to obtain a seed emulsion;

[0056] After the seed emulsion is formed, the pre-emulsion and the initiator solution are synchronously added to the seed emulsion for the second time through the constant flow pump feeding device and the constant flow dripping metering device. When the remaining amount of the pre-emulsion is 5wt% of the total amount of the pre-emulsion (i.e., the feeding amount of the pre-emulsion in S2 is 95wt% of the total amount of the pre-emulsion adopted in the preparation method), the dropping is stopped, and then 1.5g of internal plasticizing monomer dibutyl maleate (DBM) is added to the mixed solution thus obtained at one time and stirred evenly, wherein the mass of the internal plasticizing monomer DBM: the total mass of the acrylate monomers in the pre-emulsion adopted in the preparation method = 1.5:145.

[0057] S3. Continue to dropwise add the remaining pre-emulsion and the initiator solution to the mixed solution obtained after S2 is completed, the total time of dropping the pre-emulsion is controlled to 360 minutes, and ensure that the initiator solution is added 30 minutes later than the pre-emulsion, and then keep warm at 90°C for 60 minutes to obtain a first intermediate solution; then dropwise add 35g of the dispersion (the dispersion includes 23.33g of blue light absorbing aid benzophenone and 11.67g of dispersant polycarboxylate sodium salt) to the first intermediate solution, and the dropping time is controlled to 10 minutes;

[0058] S4. Control the temperature in the polymerization kettle at 80°C, keep it warm for 15 minutes, then cool it to 60°C, and simultaneously add double drops of redox initiator (the redox initiator consists of an aqueous solution containing 2.6g of tert-butyl hydroperoxide and an aqueous solution containing 2g of FF6M), the addition time is 60 minutes, keep it warm for 60 minutes, then cool it to 45°C, adjust the pH to 8 with a 5% KOH aqueous solution to obtain a third intermediate solution, and then add 10g of blue light absorbing auxiliary agent benzophenone to the third intermediate solution, followed by adding 0.03g of defoaming agent and 0.4g of quick-kill bactericide, and filter the material with a 250-mesh filter to obtain an acrylic emulsion.

[0059] Example 4

[0060] This example prepares an acrylate emulsion with reference to Example 3. The difference between this example and Example 3 is that in S3 of preparing the acrylate emulsion, 23.33 g of a blue light absorbing auxiliary agent is used to replace the dispersion in Example 3. Except for the above differences, the materials and process operations used in this example are strictly consistent with those in Example 3.

[0061] Example 5

[0062] This embodiment refers to Example 3 to prepare an acrylic emulsion. The difference between this embodiment and Example 3 is that in S3 of preparing the acrylic emulsion, the feed amount of the dispersion is adjusted to 68 g (the dispersion includes 45.33 g of benzophenone as a blue light absorbing auxiliary agent and 22.67 g of polycarboxylic acid sodium salt as a dispersant). Except for the above differences, the materials and process operations used in this embodiment are strictly consistent with those in Example 3.

[0063] Example 6

[0064] This example prepares the acrylic emulsion with reference to Example 3. The difference between this example and Example 3 is that in S4 of preparing the acrylic emulsion, the amount of the blue light absorbing auxiliary agent is adjusted to 32 g. Except for the above difference, the materials and process operations used in this example are strictly consistent with those in Example 3.

[0065] Example 7

[0066] This example prepares an acrylic emulsion with reference to Example 3. The difference between this example and Example 3 is that the blue light absorbing agent used in this example is only composed of the inorganic component TiO2. In addition to the above differences, the materials and process operations used in this example are strictly consistent with those in Example 3.

[0067] Example 8

[0068] This example prepares an acrylic emulsion with reference to Example 3. The difference between this example and Example 3 is that the blue light absorption agent used in this example is only composed of the organic component benzophenone. In addition to the above differences, the materials and process operations used in this example are strictly consistent with those in Example 3.

[0069] Example 9

[0070] This example prepares an acrylic emulsion with reference to Example 3. The difference between this example and Example 3 is that in the process of preparing the acrylic emulsion, the same mass of stearic acid phosphate is used to replace RS-610 in Example 3 as an emulsifier. Except for the above differences, the materials and process operations used in this example are strictly consistent with those in Example 3.

[0071] Example 10

[0072] This example prepares an acrylate emulsion with reference to Example 3. The difference between this example and Example 3 is that in the process of preparing the acrylate emulsion, the same mass of dodecyl mercaptan is used to replace RS-610 in Example 3 as an emulsifier. Except for the above differences, the materials and process operations used in this example are strictly consistent with those in Example 3.

[0073] Embodiment 11

[0074] This embodiment prepares the acrylic emulsion with reference to the embodiment 3. The difference between this embodiment and the embodiment 3 is that in the process of preparing the acrylic emulsion, the feeding amount of the pre-emulsion in S2 is adjusted to 55wt% of the total amount of the pre-emulsion used in the preparation method. Except for the above difference, the materials and process operations used in this embodiment are strictly consistent with those in the embodiment 3.

[0075] Example 12

[0076] This embodiment prepares the acrylic emulsion with reference to the embodiment 3. The difference between this embodiment and the embodiment 3 is that in the process of preparing the acrylic emulsion, the feeding amount of the pre-emulsion in S2 is adjusted to 98wt% of the total amount of the pre-emulsion used in the preparation method. Except for the above difference, the materials and process operations used in this embodiment are strictly consistent with those in the embodiment 3.

[0077] Comparative Example 1

[0078] A commercially available conventional styrene acrylic emulsion was used as the acrylic emulsion of this comparative example.

[0079] Comparative Example 2

[0080] A commercially available conventional pure acrylic emulsion was used as the acrylic emulsion of this comparative example.

[0081] Comparative Example 3

[0082] This comparative example refers to Example 3 to prepare an acrylic emulsion. The difference between this comparative example and Example 3 is that in the process of preparing the acrylic emulsion, the operation of adjusting the pH to 8 with a 5% KOH aqueous solution in S3 is omitted. In addition to the above differences, the materials and process operations used in this comparative example are strictly consistent with those in Example 3.

[0083] Comparative Example 4

[0084] This comparative example refers to Example 3 to prepare an acrylic emulsion. The difference between this comparative example and Example 3 is that in the raw materials of the acrylic emulsion used in this comparative example, dibutyl fumarate of the same mass is used to replace dibutyl maleate as the internal plasticizing monomer. Except for the above differences, the materials and process operations used in this comparative example are strictly consistent with those in Example 3.

[0085] Comparative Example 5

[0086] This comparative example prepares an acrylic emulsion with reference to Example 3. The difference between this comparative example and Example 3 is that the raw materials of the acrylic emulsion used in this comparative example do not include an internal plasticizing monomer. In addition to the above differences, the materials and process operations used in this comparative example are strictly consistent with those in Example 3.

[0087] Comparative Example 6

[0088] This comparative example refers to Example 3 to prepare an acrylic emulsion. The difference between this comparative example and Example 3 is that in the raw materials of the acrylic emulsion used in this comparative example, the acrylic monomer consists of 120g styrene, 20g n-butyl acrylate, 3g methacrylic acid, and 2g acrylic acid. Except for the above differences, the materials and process operations used in this comparative example are strictly consistent with those in Example 3.

[0089] Comparative Example 7

[0090] This comparative example refers to Example 3 to prepare an acrylic emulsion. The difference between this comparative example and Example 3 is that in the raw materials of the acrylic emulsion used in this comparative example, the acrylic monomer consists of 55g of styrene, 65g of n-butyl acrylate, 13g of methacrylic acid, and 12g of acrylic acid. Except for the above differences, the materials and process operations used in this comparative example are strictly consistent with those in Example 3.

[0091] Test Example 1

[0092] 1. Participants:

[0093] In this test example, the acrylic emulsions prepared in Examples 1 to 12 and Comparative Examples 1 to 7 were used to prepare emulsion films, coatings, and paint films for testing;

[0094] The preparation method of the emulsion film is as follows: a 200 μm thick emulsion film is prepared on a flat glass plate using a film former and dried in an oven at 50° C. The emulsion film obtained after drying is used as a test object of this test example.

[0095] The preparation method of the paint film is as follows: prepare the paint according to the paint formula shown in Table 1 below, then use a film former to prepare a paint film with a thickness of 200 μm on a flat glass plate and dry it in an oven at 50°C. The paint film obtained after drying is used as the test object of this test example.

[0096] Table 1. Coating formulations

[0097]

[0098]

[0099] 2. Test items:

[0100] (1) Blue light absorption efficiency: Tested in accordance with GB / T 38120-2019 Technical Requirements for Light Health and Light Safety Application of Blue Light Protection Film.

[0101] (2) Adhesion: Tested in accordance with ISO 2409-2007 “Paints and varnishes – Cross-cut test”.

[0102] (3) Flexibility and tensile strength: Tested in accordance with JC / T 864-2008 “Polymer Emulsion Building Waterproof Coatings”.

[0103] (4) Stability: 30 g of the acrylic emulsion to be tested was mixed with 5% calcium chloride solution in a ratio of 1:1, and then allowed to stand for 24 hours to observe whether coagulation, stratification or demulsification occurred.

[0104] 3. Test results:

[0105] Table 2 Performance test results of emulsion films and paint films prepared in Examples 1 to 12 and Comparative Examples 1 to 7

[0106]

[0107]

[0108] Table 3 Performance test results of coatings prepared in Examples 1 to 12 and Comparative Examples 1 to 7

[0109]

[0110]

[0111] The test results are shown in Tables 1-2. The performance test results of Example 3 are compared with those of Comparative Examples 1-2. As shown in Table 1, under the same conditions of other materials and operations for preparing the coating, Comparative Examples 1 and 2 respectively use conventional styrene acrylic emulsion and pure acrylic emulsion to prepare the coating, and the 1d, 90d, and 180d blue light absorption efficiency of the emulsion film and paint film obtained are lower than those of Example 3, and the flexibility, tensile strength, and adhesion of the coating are lower than those of Example 3. This shows that, relative to Comparative Examples 1-2, Example 3 uses a specific acrylic emulsion, and the components in the acrylic emulsion can play a synergistic role, so that the emulsion has continuous blue light absorption efficiency and film-forming properties, and the coating has good mechanical properties and adhesion.

[0112] By comparing the performance test results corresponding to Example 3 and Comparative Example 3, it can be found that the 1d, 90d, and 180d blue light absorption efficiency of the emulsion film and paint film prepared in Comparative Example 3 is lower than that of Example 3, and the flexibility, tensile strength, adhesion, and stability of the coating are lower than those of Example 3. The reason is that under the same conditions of other materials and operations for preparing the coating, Comparative Example 3 did not adjust the pH of the system in the S4 stage, which was not conducive to the dispersibility and stability of the blue light absorption agent and the emulsion, thereby significantly deteriorating the continuous blue light absorption efficiency, mechanical properties, and adhesion of the coating.

[0113] The performance test results of Example 3 are compared with those of Comparative Examples 4 to 5. As shown in Table 1, under the same conditions of other materials and operations for preparing the coating, Comparative Example 4 uses dibutyl fumarate as the internal plasticizing monomer, and Comparative Example 5 does not add the internal plasticizing monomer, and the 1d, 90d, and 180d blue light absorption efficiency of the emulsion film and paint film obtained are lower than those of Example 3, and the flexibility, tensile strength, and adhesion of the coating are lower than those of Example 3. This shows that, relative to Comparative Examples 4 to 5, Example 3 adopts a specific internal plasticizer monomer, so that the internal plasticizer monomer is synergistically matched with the acrylate monomer and the blue light absorbing agent, thereby reducing the film-forming temperature of the acrylate emulsion, improving the cohesive force of the acrylate emulsion, and being beneficial to controlling the particle size and particle size distribution uniformity of the emulsion particles in the acrylate emulsion, promoting the blue light absorbing agent to be stably and evenly dispersed in the emulsion particles, allowing the blue light absorbing agent to continuously exert its blue light absorbing function, and at the same time promoting the acrylate emulsion to form a dense and uniform emulsion film, thereby making the blue light absorption efficiency and continuous blue light absorption efficiency of the emulsion better, and making the mechanical properties and adhesion of the coating better.

[0114] The performance test results of Example 3 are compared with those of Comparative Examples 6 to 7. As shown in Table 1, under the same conditions of other materials and operations for preparing the coating, the mass ratio of monovinyl aromatic monomer, (meth) alkyl acrylate, α,β-monoethylenically unsaturated C2-C16 monocarboxylic acid or dicarboxylic acid in the acrylate monomers used in Comparative Examples 6 and 7 does not meet (25 to 85): (15 to 75): (0.01 to 8), and the 1d, 90d, and 180d blue light absorption efficiency of the emulsion film and paint film obtained are lower than those of Example 3, and the flexibility, tensile strength, and adhesion of the coating are lower than those of Example 3. This shows that, relative to Comparative Examples 6 to 7, Example 3 reasonably sets the ratio of each component in the acrylate monomer, so that the acrylate monomer is coordinated with the internal plasticizer monomer and the blue light absorption aid, thereby making the blue light absorption efficiency and sustained blue light absorption efficiency of the emulsion better, and making the mechanical properties and adhesion of the coating better.

[0115] Comparing the performance test results corresponding to Example 3 with those of Examples 4 to 6, it can be found that the 1d, 90d, and 180d blue light absorption efficiency of the emulsion film and paint film prepared in Examples 4 to 6 is lower than that in Example 3, and the flexibility, tensile strength, and adhesion of the coating are lower than those in Example 3. The reason is that, under the same conditions of other materials and operations for preparing the coating, in Example 4, the blue light absorption agent is directly introduced into the reaction system in S3, the feed amount of the dispersion containing the blue light absorption agent in S3 of Example 5 is too much, and the feed amount of the blue light absorption agent in S4 of Example 6 is too much, which is not conducive to the uniform and stable dispersion of the blue light absorption agent in the emulsion, resulting in stratification and precipitation of the emulsion, thereby deteriorating the blue light absorption efficiency, continuous blue light absorption efficiency, mechanical properties, and adhesion of the coating.

[0116] The performance test results of Example 3 are compared with those of Examples 7 to 8. As shown in Table 1, under the same conditions of other materials and operations for preparing the coating, the blue light absorbing agent used in Example 7 only includes inorganic components, and the blue light absorbing agent used in Example 8 only includes organic components. The 1d, 90d, and 180d blue light absorbing efficiency of the emulsion film and paint film obtained are lower than those of Example 3, and the flexibility, tensile strength, and adhesion of the coating are lower than those of Example 3. This shows that, relative to Examples 7 to 8, Example 3 introduces a specific blue light absorbing agent, and the inorganic and organic components in the blue light absorbing agent can work together to make the blue light absorption efficiency and sustained blue light absorption efficiency of the emulsion better, and the blue light absorbing agent can play a synergistic role with the acrylate monomer and the internal plasticizer monomer to improve the cohesion and film-forming properties of the acrylate emulsion, thereby making the mechanical properties and adhesion of the coating better.

[0117] The performance test results of Example 3 are compared with those of Examples 9-10. As shown in Table 1, under the same conditions of other materials and operations for preparing the coating, Examples 9 and 10 respectively use stearic acid phosphate and dodecyl mercaptan as emulsifiers, and the 1d, 90d, and 180d blue light absorption efficiency of the emulsion film and paint film obtained are lower than that of Example 3, and the flexibility, tensile strength, and adhesion of the coating are lower than those of Example 3. This shows that, relative to Examples 9-10, Example 3 uses branched alkyl alcohol polyoxyethylene ether phosphate monoester as an emulsifier, and the emulsifier molecule contains polyoxyethylene ether groups and phosphate monoester groups, and the polyoxyethylene ether groups and phosphate monoester groups have high stability and good emulsification, dispersing and wetting properties, which can promote the uniform dispersion of particles in the emulsion, prevent droplet aggregation, and promote the formation of a stable and firm emulsified film, thereby making the sustained blue light absorption efficiency of the emulsion better and the mechanical properties and adhesion of the coating better.

[0118] Comparing the performance test results corresponding to Example 3 with those of Examples 11-12, it can be found that the 1d, 90d, and 180d blue light absorption efficiency of the emulsion film and paint film prepared in Examples 11-12 is lower than that in Example 3, and the flexibility, tensile strength, and adhesion of the coating are lower than those in Example 3. The reason is that, under the same conditions of other materials and operations for preparing the coating, the timing of feeding the internal plasticizer monomer in Example 11 is relatively early, resulting in a high local concentration of the monomer and uncontrollable polymerization rate, leading to uneven molecular weight distribution of the polymerization product, thereby deteriorating the blue light absorption efficiency, sustained blue light absorption efficiency, mechanical properties, and adhesion of the coating; the timing of feeding the internal plasticizer monomer in Example 12 is relatively late, resulting in incomplete polymerization reaction, residual more unreacted internal plasticizer monomer, and reducing its effective utilization rate, thereby deteriorating the blue light absorption efficiency, sustained blue light absorption efficiency, mechanical properties, and adhesion of the coating.

[0119] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention is described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the technical solutions of the present invention can be modified or equivalently replaced, but these modifications or replacements are all within the protection scope of the present invention.

Claims

1. An acrylic emulsion, characterized in that: Calculated by weight, the raw materials of the acrylic emulsion include 40 to 168 parts of acrylic monomer, 0.1 to 10 parts of internal plasticizer monomer, 0.01 to 5 parts of emulsifier, 0.01 to 2 parts of initiator, and 0.1 to 38 parts of blue light absorption aid; The acrylic acid ester monomer comprises a monovinyl aromatic monomer, an alkyl (meth)acrylate and an α,β-monoethylenically unsaturated C2-C16 monocarboxylic acid or dicarboxylic acid, wherein the mass ratio of the monovinyl aromatic monomer, the alkyl (meth)acrylate and the α,β-monoethylenically unsaturated C2-C16 monocarboxylic acid or dicarboxylic acid is (25-85): (15-75): (0.01-8); The internal plasticizing monomer includes dibutyl maleate; The pH of the acrylic ester emulsion is 6-9.

2. The acrylic emulsion according to claim 1, characterized in that: The blue light absorption auxiliary agent includes an inorganic component and an organic component, the inorganic component includes TiO2, and the organic component includes at least one of benzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 4-hydroxybenzophenone, benzotriazole, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, and 2-(2'-hydroxy-3',5'-dipentylphenyl)benzotriazole.

3. The acrylic emulsion according to claim 2, characterized in that: The emulsifier includes branched alkyl alcohol polyoxyethylene ether phosphate monoester.

4. The acrylic emulsion according to claim 2, characterized in that: The raw materials of the acrylic ester emulsion also include a dispersant, and the dispersant includes a sodium salt of polycarboxylate.

5. A coating, characterized in that: The invention comprises the acrylic ester emulsion as claimed in any one of claims 1 to 4.

6. A method for preparing an acrylic emulsion, characterized in that: The preparation method of the acrylic emulsion comprises the following operations: S1. The blue light absorbing agent, the acrylate monomer, the emulsifier and water are mixed to prepare a pre-emulsion; S2. adding part of the pre-emulsion and the initiator solution to the emulsion at 85 to 90° C. to obtain a seed emulsion; then adding part of the pre-emulsion and the initiator solution to the seed emulsion, and then adding an internal plasticizing monomer to the resulting mixture; S3. Add the remaining pre-emulsion and the initiator solution to the mixed solution obtained after the completion of S2 and keep warm at 85 to 90° C. to obtain a first intermediate solution; then add the blue light absorbing agent to the first intermediate solution to obtain a second intermediate solution; S4. Adjust the pH of the second intermediate liquid to 6-9 to obtain a third intermediate liquid, and then add the blue light absorbing auxiliary agent to the third intermediate liquid to prepare an acrylic emulsion.

7. The method for preparing the acrylic emulsion according to claim 6, characterized in that: In S3, the blue light absorbing aid is added in the form of a dispersion, the dispersion includes the blue light absorbing aid and a dispersant, the dispersant includes sodium polycarboxylate, and the mass ratio of the dispersant to the blue light absorbing aid is 1:(1.5-2.5).

8. The method for preparing the acrylic emulsion according to claim 7, characterized in that: The amount of the blue light absorbing aid is determined according to the mass of the acrylate monomer in the pre-emulsion: the mass of the blue light absorbing aid in S1: the mass of the dispersion in S3: the mass of the blue light absorbing aid in S4 = (50-168): (0.1-4): (1-38): (2-10).

9. The method for preparing the acrylic emulsion according to claim 6, characterized in that: The feeding amount of the pre-emulsion in S2 is 60-95wt% of the total amount of the pre-emulsion used in the preparation method; The mass of the internal plasticizing monomer: the total mass of the acrylic acid ester monomers in the pre-emulsion used in the preparation method = (0.1-10): (40-168).

10. A coating, characterized in that: The invention comprises an acrylate emulsion, wherein the acrylate emulsion is prepared by the preparation method of the acrylate emulsion according to any one of claims 6 to 9.

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