Elastic acrylic emulsion with high color developing performance and preparation method thereof

Abstract

The invention provides an elastic acrylic emulsion with high color developing performance and a preparation method thereof, the elastic acrylic emulsion is prepared from the following raw materials in parts by mass: 90-210 parts of a water-based solvent, 100-360 parts of a polymeric monomer, 2-30 parts of a functional monomer and 0.5-9.5 parts of auxiliaries, and the auxiliaries comprise an emulsifier and an initiator; wherein the polymeric monomer comprises butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate and styrene, and the mass ratio of butyl acrylate to 2-ethylhexyl acrylate to methyl methacrylate to styrene is (6-15): (1-5): (1-6): (2-10); the functional monomer comprises at least one of a long-chain monomer and an amido monomer, the long-chain monomer is an alkenyl monomer with a main carbon chain comprising more than 9 carbon atoms, and the amido monomer further comprises alkenyl. The elastic acrylic emulsion has the advantages of being good in color contrast property, good in ductility and good in mechanical property.

Description

Technical Field

[0001] The invention relates to the field of acrylic emulsions, in particular to an elastic acrylic emulsion with high color development performance and a preparation method thereof. Background Art

[0002] As people's consumption level and aesthetic taste improve, there are more requirements for the color matching and design of building exterior walls. Therefore, people are paying more and more attention to the color development of emulsions in order to obtain more vivid and uniform color performance. Color development refers to the ability of emulsion to show the color of color paste after mixing with color paste. Excellent color development means that the color can be evenly distributed, avoiding color spots, color differences and other phenomena, ensuring that the color of the paint product is full and lasting.

[0003] Elastic acrylic emulsion has the advantages of good resilience, flexibility, adhesion, waterproofness, weather resistance, dust resistance and UV resistance. However, elastic acrylic emulsion exhibits poor color development, which can easily lead to problems such as floating color and blooming in the paint using the elastic acrylic emulsion. These problems will affect the appearance quality and color uniformity of the paint film formed by the paint.

[0004] Therefore, it is necessary to develop an elastic acrylic emulsion with excellent color development properties to address the above defects. Summary of the invention

[0005] The object of the present invention is to provide an elastic acrylic emulsion with high color development performance and a preparation method thereof. The elastic acrylic emulsion has the advantages of good color development, good ductility and good mechanical properties.

[0006] According to one aspect of the present invention, an elastic acrylic emulsion with high color development performance is provided. Calculated by weight, raw materials for preparing the elastic acrylic emulsion include: 90-210 parts of aqueous solvent, 100-360 parts of polymerized monomers, 2-30 parts of functional monomers, and 0.5-9.5 parts of auxiliary agents, wherein the auxiliary agents include emulsifiers and initiators; wherein the polymerized monomers include butyl acrylate, isooctyl acrylate, methyl methacrylate, and styrene, and the mass ratio of butyl acrylate, isooctyl acrylate, methyl methacrylate, and styrene is 6-15:1-5:1-6:2-10; the functional monomer includes at least one of a long-chain monomer and an amide monomer, wherein the long-chain monomer is an olefin monomer having a main carbon chain of more than 9 carbon atoms, and the amide monomer also includes an olefin group.

[0007] The use of the above-mentioned polymerized monomers and functional monomers is conducive to the preparation of an elastic acrylic emulsion with low solid content, good color development, good ductility and good mechanical properties. The use of polymerized monomers that meet the above-mentioned composition ratio can not only make the glass transition temperature (Tg) of the emulsion within the ideal range, but also help to improve the ductility and mechanical strength of the emulsion, and help the ductility and mechanical strength of the emulsion to achieve a good balance, and achieve the harmonious unity of the performance of the two. The elastic acrylic emulsion prepared by using the above-mentioned functional monomers and polymerized monomers can enhance the tensile properties of the polymer molecular chains in the emulsion, and then greatly improve the ductility of the paint film prepared by the emulsion. At the same time, the above-mentioned emulsion has good compatibility with the pigment, which is conducive to improving the dispersibility of the pigment in the coating containing the emulsion and making the color development of the coating uniform. In addition, the above-mentioned emulsion exhibits a lower viscosity under the condition of low solid content, which is conducive to more finely regulating the particle size and particle size distribution of the emulsion, thereby further optimizing the color development performance of the emulsion. The tensile properties of the molecular chains of the emulsion are more excellent, which improves the ductility of the paint film formed by the application of the emulsion, and improves the binding force between the pigment and the polymer chain, which is beneficial to the dispersion of the color paste and improves the color development, making the pigment molecules more evenly dispersed; at the same time, the viscosity of the emulsion is low under low solid content conditions, which can better control the particle size and distribution of the emulsion, making its color development performance more excellent. In summary, compared with commercially available emulsions, the elastic acrylic emulsion with high color development performance provided by the present invention exhibits excellent color display, excellent ductility and excellent mechanical properties.

[0008] Preferably, the functional monomer includes a long-chain monomer and an amide monomer. When the functional monomer includes a long-chain monomer and an amide monomer, it is beneficial to prepare an emulsion with strong color development. The main carbon chain of the long-chain monomer is long, and the amide monomer has a bifunctional group structure of an amide group and a double bond. Therefore, in the polymer molecular chain obtained by polymerization of the functional monomer and the polymerized monomer, the main carbon chain of the long-chain monomer will be converted into a long side chain of the polymer molecular chain, and the long side chain structure will be entangled, so that the long side chain structure itself and the adjacent molecular chains are entangled together; the amide group and the unsaturated bonds of other monomers are condensed, so that the polymer molecular chain has a network cross-linked structure. As a result, the polymer molecular chain including the entangled structure and the network cross-linked structure has a certain hydrophobicity, which is beneficial to the uniform distribution of the pigment in the emulsion medium, effectively reducing the mutual aggregation tendency between the pigment particles, and preventing the occurrence of agglomeration, so that each pigment molecule can be independently and evenly distributed in the emulsion, thereby enhancing the color development performance and color expression of the emulsion, so that the paint film using the emulsion can achieve a uniform, delicate and full visual effect.

[0009] Preferably, the mass ratio of long-chain monomers to amide monomers is 2 to 10:3 to 15. By adjusting the mass ratio of long-chain monomers to amide monomers within the above-mentioned ratio range, the proportion of entangled structures and network cross-linked structures in the polymer molecular chain can be regulated, thereby adjusting the degree of freedom of movement of the chain segments in the polymer molecular chain, thereby improving the elongation and flexibility of the elastic acrylic emulsion. Specifically, when the paint film formed by the emulsion is squeezed by an external force, the polymer molecular chains with entangled structures and network cross-linked structures can provide the paint film with good flexibility and mechanical strength. When the paint film is stretched by force, the entangled structure in the polymer molecular chain will gradually untie, thereby improving the elongation of the paint film prepared by the emulsion.

[0010] Preferably, the raw materials for preparing the elastic acrylic emulsion also include 0.2 to 5 parts of unsaturated organic acid, calculated by weight, and the unsaturated organic acid includes at least one of itaconic acid, methacrylic acid, and acrylic acid. By introducing unsaturated organic acids into the emulsion, not only can the emulsion be maintained stable, but more cross-linking active sites can also be provided for the polymer molecular chains, which is beneficial for the paint film formed by the emulsion to have excellent mechanical properties. In particular, when the functional monomer includes an amide monomer, by adjusting the addition amount of the unsaturated organic acid to 0.2 to 5 parts, it is beneficial for the unsaturated organic acid to promote the reaction between the amide monomer and the carboxyl group in the polymerized monomer, effectively promote the formation of a network cross-linked structure, and endow the paint film formed by the emulsion with excellent mechanical strength and structural stability.

[0011] Preferably, the functional monomer further includes 1 to 6 parts of silicone monomers, calculated by weight, and the silicone monomers include vinyl trimethoxysilane, methacryloxysilane, and vinyl triethoxysilane. By introducing silicone monomers into the elastic acrylic emulsion, the hydrophobicity of the paint film formed by the emulsion can be further improved, thereby constructing a protective barrier for the paint film, greatly reducing the erosion of water on the paint film structure, thereby reducing the migration probability of hydrophilic substances inside the paint film. In particular, when the functional monomer includes a long-chain monomer, by adjusting the amount of silicone monomer added to fall within the above-mentioned weight range, it is beneficial to improve the rain mark resistance of the paint film, so that the paint film can maintain the integrity of its appearance for a long time when it is exposed to rain erosion for a long time.

[0012] Preferably, the organosilicon monomer comprises vinyltrimethoxysilane.

[0013] Preferably, the long-chain monomer includes at least one of lauryl acrylate, octadecyl acrylate, caprolactone methacrylate, and lauryl methacrylate.

[0014] Preferably, the emulsifier includes at least one of sodium dodecylbenzene sulfonate, monolaurin, sodium oleate, propylene glycol fatty acid ester, and sodium dodecyl polyoxyethylene sulfate. The above emulsifier has excellent emulsifying properties and low surface tension, can form a hydration protective layer on the surface of latex particles, and is beneficial to the storage stability of the emulsion.

[0015] Preferably, the initiator includes at least one of ammonium persulfate, potassium persulfate and sodium persulfate. The above initiator can decompose free radicals after being heated, and the free radicals can initiate polymerization monomers and / or unsaturated bonds in functional monomers to be affected by the free radicals, and further undergo grafting, copolymerization and other reactions, thereby improving the mechanical properties of the emulsion after film formation.

[0016] Preferably, the auxiliary agent includes an oxidant and a reducing agent, the oxidant includes at least one of sodium persulfate, hydrogen peroxide, ammonium persulfate, and tert-butyl hydroperoxide, and the reducing agent includes one of sodium pyrosulfite, sodium bisulfite, FF6, and isoascorbic acid. By introducing the oxidant and the reducing agent into the elastic acrylic emulsion, it is beneficial to provide free radicals for the reaction of the residual, unreacted polymerized monomers and / or functional monomers, improve the degree of reaction, and reduce the amount of residual monomers in the emulsion.

[0017] Preferably, calculated by weight, the polymerizable monomers include 60 to 150 parts of butyl acrylate, 10 to 50 parts of isooctyl acrylate, 10 to 60 parts of methyl methacrylate, and 20 to 100 parts of styrene.

[0018] Preferably, calculated by weight, the auxiliary agent includes 0.6 to 5 parts of emulsifier, 0.10 to 3.8 parts of initiator, 0.02 to 0.3 parts of reducing agent, and 0.02 to 0.3 parts of oxidant.

[0019] Preferably, the solid content of the elastic acrylic emulsion with high color development performance is 40% to 58%.

[0020] According to another aspect of the present invention, there is provided a method for preparing the elastic acrylic emulsion with high color development performance, comprising the following steps: S1. mixing a polymerizable monomer, a part of a functional monomer, a part of an initiator, a part of an emulsifier and a part of a solvent to obtain a prepolymer solution, and dividing the prepolymer solution into a first prepolymer solution and a second prepolymer solution according to a mass ratio, wherein the mass of the first prepolymer solution is 1 to 10% of the total mass of the prepolymer solution; S2. mixing the remaining solvent, the first prepolymer solution, the remaining emulsifier and the remaining initiator at 70 to 88° C. to obtain a first reaction solution, and heating the first reaction solution at 70 to 88° C. The method comprises the following steps: reacting the prepolymer solution at a temperature of 0 to 88°C for 1 to 30 minutes to obtain a second reaction solution, then dripping the second prepolymer solution into the second reaction solution at a temperature of 70 to 88°C for 150 to 200 minutes, and keeping the temperature at 70 to 88°C for 1 to 1.5 hours to obtain a third reaction solution; S3. mixing the third reaction solution with the remaining auxiliary agent at a temperature of 70 to 85°C, and keeping the temperature for 10 to 30 minutes to obtain a fourth reaction solution, and then mixing the fourth reaction solution with the remaining functional monomer at a temperature of 45 to 55°C to obtain an elastic acrylic emulsion with high color development performance. The semi-continuous dripping reaction method is used to prepare the elastic acrylic emulsion with high color development performance, which is not only conducive to reducing the emulsion solid content of the elastic acrylic emulsion, but also improves the color development and mechanical properties of the emulsion. Moreover, the above-mentioned preparation process is simple, convenient to operate, low in cost, mild in conditions, and has good economic benefits. In addition, by utilizing the post-elimination operation of S3, the polymerization of unreacted monomers in the emulsion into the polymer molecular chains of the emulsion can be promoted, thereby reducing the VOC content of the elastic acrylic emulsion.

[0021] Preferably, the method comprises the following steps: S1. mixing a polymerizable monomer, 2 to 25 parts of a functional monomer, 0.05 to 3.5 parts of an initiator, 0.6 to 5.5 parts of an emulsifier and 60 to 110 parts of a solvent to obtain a prepolymer solution, and dividing the prepolymer solution into a first prepolymer solution and a second prepolymer solution according to a mass ratio, wherein the mass of the first prepolymer solution is 1 to 10% of the total mass of the prepolymer solution; S2. mixing the remaining solvent, the first prepolymer solution, the remaining emulsifier and the remaining initiator at 70 to 88° C. to obtain a first reaction solution, and heating the first reaction solution at a temperature of 70 to 88° C. S3. mixing the third reaction liquid with an oxidant and a reductant at a temperature of 70 to 85° C., and keeping the temperature for 10 to 30 minutes to obtain a fourth reaction liquid, and then mixing the fourth reaction liquid with the remaining functional monomers at a temperature of 45 to 55° C. to obtain an elastic acrylic emulsion with high color development performance. DETAILED DESCRIPTION

[0022] 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.

[0023] Example 1

[0024] This embodiment provides an elastic acrylic emulsion with high color development performance, and the elastic acrylic emulsion with high color development performance is composed of the following components:

[0025] Table 1. Raw material composition of the elastic acrylic emulsion with high color development performance in Example 1

[0026]

[0027]

[0028] The method for preparing the elastic acrylic emulsion with high color development performance is characterized by comprising the following steps:

[0029] S1. The polymerizable monomer, 2 parts of vinyl trimethoxysilane, 4 parts of lauryl acrylate, 5 parts of acrylamide, 0.2 parts of initiator, 0.6 parts of emulsifier and 60 parts of solvent are mixed to prepare a prepolymer solution, and the prepolymer solution is divided into a first prepolymer solution and a second prepolymer solution according to the mass ratio, the mass of the first prepolymer solution is 3% of the total mass of the prepolymer solution, and the mass of the second prepolymer solution is 97% of the total mass of the prepolymer solution;

[0030] S2. At 84°C, the remaining solvent, the remaining emulsifier, the remaining initiator and the first prepolymer solution were uniformly mixed to obtain a first reaction solution, the first reaction solution was reacted at a temperature of 86°C for 15 minutes to obtain a second reaction solution, and then the second prepolymer solution was added dropwise to the second reaction solution at a temperature of 86°C for 180 minutes. After the addition was completed, the mixture was kept warm at a temperature of 86°C for 1 hour to obtain a third reaction solution;

[0031] S3. The third reaction liquid is mixed with a reducing agent and an oxidizing agent at a temperature of 75° C. and kept warm for 20 minutes to obtain a fourth reaction liquid, and then the fourth reaction liquid is mixed with the remaining functional monomers at a temperature of 45° C. to obtain an elastic acrylic emulsion with high color development performance. The elastic acrylic emulsion with high color development performance has a solid content of 48%, a pH value of 7.4, and a rotational viscosity of 434 cps (2# / 30R, 25° C.).

[0032] In other embodiments, the type and amount of the emulsifier, initiator, reducing agent or oxidizing agent may be adjusted according to actual conditions, provided that the normal preparation of the coating is not affected.

[0033] Example 2

[0034] This embodiment refers to the preparation method provided in Example 1 to prepare an elastic acrylic emulsion with high color development performance. The difference between this embodiment and Example 1 is that the feed amount of each monomer in the polymerization monomer is adjusted so that the mass ratio of butyl acrylate, isooctyl acrylate, methyl methacrylate, and styrene is regulated to 6:1:1:2 while maintaining the total feed amount of the polymerization monomer unchanged. Specifically, according to the mass fraction, the polymerization monomer includes 72 parts of butyl acrylate, 12 parts of isooctyl acrylate, 12 parts of methyl methacrylate, and 24 parts of styrene, and the remaining raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0035] Example 3

[0036] This embodiment refers to the preparation method provided in Example 1 to prepare an elastic acrylic emulsion with high color development performance. The difference between this embodiment and Example 1 is that the feed amount of each monomer in the polymerization monomer is adjusted so that the mass ratio of butyl acrylate, isooctyl acrylate, methyl methacrylate, and styrene is regulated to 15:5:6:10 while maintaining the total feed amount of the polymerization monomer unchanged. Specifically, according to the mass fraction, the polymerization monomer includes 50 parts of butyl acrylate, 17 parts of isooctyl acrylate, 20 parts of methyl methacrylate, and 33 parts of styrene, and the remaining raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0037] Example 4

[0038] This example refers to the preparation method provided in Example 1 to prepare an elastic acrylic emulsion with high color development performance. The difference between this example and Example 1 is that the same mass of lauryl acrylate is used to replace the acrylamide and vinyl trimethoxysilane in Example 1, that is, the functional monomer is a long-chain monomer. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0039] Example 5

[0040] This example refers to the preparation method provided in Example 1 to prepare an elastic acrylic emulsion with high color development performance. The difference between this example and Example 1 is that acrylamide of equal mass is used to replace lauryl acrylate and vinyl trimethoxy silane in Example 1, that is, the functional monomer is an amide monomer. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0041] Example 6

[0042] This example refers to the preparation method provided in Example 1 to prepare an elastic acrylic emulsion with high color development performance. The difference between this example and Example 1 is that an aqueous solvent of equal mass is used to replace the vinyl trimethoxysilane in Example 1, that is, the functional monomers are amide monomers and long-chain monomers. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0043] Example 7

[0044] This example refers to the preparation method provided in Example 1 to prepare an elastic acrylic emulsion with high color development performance. The difference between this example and Example 1 is that the feed amounts of lauryl acrylate and acrylamide are adjusted so that the mass ratio of the long-chain monomer to the amide monomer is regulated to 1:15 while maintaining the total feed amount of the functional monomer unchanged. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0045] Example 8

[0046] This example refers to the preparation method provided in Example 1 to prepare an elastic acrylic emulsion with high color development performance. The difference between this example and Example 1 is that the feed amounts of lauryl acrylate and acrylamide are adjusted so that the mass ratio of the long-chain monomer to the amide monomer is regulated to 2:15 while maintaining the total feed amount of the functional monomer unchanged. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0047] Example 9

[0048] This example refers to the preparation method provided in Example 1 to prepare an elastic acrylic emulsion with high color development performance. The difference between this example and Example 1 is that the feed amounts of lauryl acrylate and acrylamide are adjusted so that the mass ratio of the long-chain monomer to the amide monomer is regulated to 10:3 while maintaining the total feed amount of the functional monomer unchanged. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0049] Example 10

[0050] This example refers to the preparation method provided in Example 1 to prepare an elastic acrylic emulsion with high color development performance. The difference between this example and Example 1 is that the feed amounts of lauryl acrylate and acrylamide are adjusted so that the mass ratio of the long-chain monomer to the amide monomer is regulated to 11:3 while maintaining the total feed amount of the functional monomer unchanged. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0051] Embodiment 11

[0052] This example refers to the preparation method provided in Example 1 to prepare an elastic acrylic emulsion with high color development performance. The difference between this example and Example 1 is that an equal mass of solvent is used to replace the unsaturated organic acid in Example 1. The rest of the raw material ratios and preparation methods are strictly consistent with Example 1.

[0053] Comparative Example 1

[0054] This example refers to the preparation method provided in Example 1 to prepare an acrylic emulsion. The difference between this example and Example 1 is that styrene of equal mass is used to replace methyl methacrylate in Example 1. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0055] Comparative Example 2

[0056] This example refers to the preparation method provided in Example 1 to prepare an acrylic emulsion. The difference between this example and Example 1 is that styrene of equal mass is used to replace butyl acrylate in Example 1. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0057] Comparative Example 3

[0058] This example refers to the preparation method provided in Example 1 to prepare an acrylic emulsion. The difference between this example and Example 1 is that the same mass of vinyl trimethoxy silane is used to replace the lauryl acrylate and acrylamide in Example 1, that is, the functional monomer is an organic silicon monomer. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0059] Example 12

[0060] This embodiment uses the elastic acrylic emulsion with high color development performance provided by the above-mentioned embodiments 1 to 11 and comparative examples 1 to 3 to prepare a coating, and the components of the coating are as follows:

[0061] Table 2. Raw material composition of coatings

[0062] composition Mass fraction water 25.75 Lotion 32 Thickener 0.45 pH Adjusters 0.15 Dispersants 1 Wetting Agents 0.2 Defoaming agent 0.6 Titanium dioxide 15 800 mesh heavy calcium 15 1250 mesh heavy calcium 8 antifreeze 1.2 Film-forming aids 0.5 Fungicides 0.15

[0063] Note: The emulsions in Table 2 correspond to the elastic acrylic emulsions with high color development performance provided by Examples 1 to 11 and the acrylic emulsions provided by Comparative Examples 1 to 3, respectively.

[0064] Test Example 1

[0065] Test objects: the elastic acrylic emulsion with high color development performance provided in Examples 1 to 11, the acrylic emulsion provided in Comparative Examples 1 to 3; and the coating prepared according to the emulsions provided in Examples 1 to 11 and Comparative Examples 1 to 3. The specific composition of the coating is shown in Example 12.

[0066] Test items and test methods:

[0067] (1) VOC content: refer to the test method in GB / T 18582-2008 Limits of Hazardous Substances in Interior Wall Paints for Indoor Decoration and Renovation Materials, and record the VOC content of the emulsion used as the test object.

[0068] (2) Elongation performance: Refer to the test method in "JGT 172-2014 Elastic Building Emulsion" and record the elongation at break and tensile strength of the paint film formed by the paint as the test object.

[0069] (3) Color development: The paint to be tested was mixed with carbon black slurry, with the mass ratio of carbon black slurry to emulsion being 5:32. The mixed paint was applied on the substrate to form a paint film with a thickness of 100 μm. After the paint film was completely dry, it was tested using a colorimeter and the L value was recorded. The smaller the L value, the better the color development.

[0070] Table 3. Performance test results of this test case

[0071]

[0072]

[0073] Result analysis:

[0074] From the test performance shown in Table 3, compared with the emulsions provided in Comparative Examples 1 to 3, the emulsions provided in Examples 1 to 11 exhibit lower VOC content, and the paint films formed by the emulsions have better elongation at break, tensile strength and better color development performance.

[0075] By comparing the test results of Examples 1 to 2 with those of Comparative Examples 1 to 2 shown in Table 3, it can be found that the VOC content of the emulsions of Examples 1 to 11, the mechanical properties of the paint films and the color development properties are better than those of the paint films formed by Comparative Examples 1 to 2. This shows that when the polymerized monomers include butyl acrylate, isooctyl acrylate, methyl methacrylate and styrene, and the mass ratio of butyl acrylate, isooctyl acrylate, methyl methacrylate and styrene is 6 to 15:1 to 5:1 to 6:2 to 10, the paint film formed by the acrylic emulsion has good elongation at break, tensile strength and excellent color development.

[0076] Comparing the test results of Example 1, Examples 4 to 6 with Comparative Example 3, it can be found that the comprehensive performance of the paint films provided by Examples 1 and Examples 4 to 6 is better than that of the paint film provided by Comparative Example 3. This shows that when the functional monomer includes at least one of a long-chain monomer and an amide monomer, the ductility of the paint film can be improved. Further, by comparing the paint films provided by Examples 4 to 6, it can be found that the L value of the paint film provided by Example 6 is less than that of the paint films provided by Examples 4 to 5, which shows that compared with the emulsion prepared by using only a single functional monomer, the use of functional monomers including both long-chain monomers and amide monomers can improve the color development of the emulsion, which is beneficial to the dispersion of the pigment paste and makes the pigment molecules more evenly dispersed, so it is reflected in the smaller L value of the paint film. Secondly, it was found during the experiment that compared with the paint film provided by Example 6, the paint film provided by Example 1 has better hydrophobicity, water resistance and rain mark resistance. Even if the paint film is exposed to rain scouring for a long time, it is not easy to leave stains on the surface of the paint film. This shows that the water resistance and rain mark resistance of the paint film formed by the emulsion can be improved by introducing silicone monomers into the emulsion.

[0077] Comparing the test results of Example 1 with those of Examples 7 to 10, it can be found that the comprehensive performance of the paint films provided by Examples 1 and 8 to 9 is better than that of the paint films provided by Examples 7 and 10. This shows that when the mass ratio of the long-chain monomer to the amide monomer is 2 to 10:3 to 15, the mechanical properties and color development properties of the paint film formed by the emulsion are better.

[0078] By comparing the paint films provided by Example 1 and Example 11, it can be found that compared with the paint film provided by Example 11, the paint film provided by Example 1 has a lower VOC content, a higher elongation at break and a higher tensile strength. This shows that by introducing unsaturated organic acids into the emulsion, more cross-linking active sites can be provided for the polymer molecular chains, which is beneficial for the paint film formed by the emulsion to have excellent mechanical properties.

[0079] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A high color development elastic acrylic emulsion, It is characterized in that Calculated by weight, the raw materials for preparing the elastic acrylic emulsion include: 90 to 210 parts of aqueous solvent, 100 to 360 parts of polymerizable monomers, 2 to 30 parts of functional monomers, and 0.5 to 9.5 parts of auxiliary agents, wherein the auxiliary agents include emulsifiers and initiators; Among them, the polymerization monomers include butyl acrylate, isooctyl acrylate, methyl methacrylate, and styrene, and the mass ratio of the butyl acrylate, the isooctyl acrylate, the methyl methacrylate, and the styrene is 6-15:1-5:1-6:2-10; the functional monomers include at least one of a long-chain monomer and an amide monomer, the long-chain monomer is an olefinic monomer whose main carbon chain includes more than 9 carbon atoms, and the amide monomer also contains an olefinic group.

2. The elastic acrylic emulsion with high color development performance as claimed in claim 1, It is characterized in that The functional monomer includes the long-chain monomer and the amide monomer.

3. The elastic acrylic emulsion with high color development performance as claimed in claim 2, It is characterized in that The mass ratio of the long-chain monomer to the amide monomer is 2-10:3-15.

4. The elastic acrylic emulsion with high color development performance as claimed in claim 1, It is characterized in that Calculated by weight, the raw materials for preparing the elastic acrylic emulsion also include 0.2 to 5 parts of an unsaturated organic acid, and the unsaturated organic acid includes at least one of itaconic acid, methacrylic acid, and acrylic acid.

5. The elastic acrylic emulsion with high color development performance as claimed in claim 1, It is characterized in that Calculated by weight, the functional monomer further comprises 1 to 6 parts of an organic silicon monomer, and the organic silicon monomer comprises vinyl trimethoxy silane, methacryloxy silane, and vinyl triethoxy silane.

6. The elastic acrylic emulsion with high color development performance as claimed in claim 1, It is characterized in that The long-chain monomer includes at least one of lauryl acrylate, octadecyl acrylate, caprolactone methacrylate, and lauryl methacrylate.

7. The elastic acrylic emulsion with high color development performance as claimed in claim 1, It is characterized in that The emulsifier includes at least one of sodium dodecylbenzene sulfonate, lauric acid monoglyceride, sodium oleate, propylene glycol fatty acid ester, and sodium dodecyl polyoxyethylene sulfate.

8. The elastic acrylic emulsion with high color development performance as claimed in claim 1, It is characterized in that The initiator includes at least one of ammonium persulfate, potassium persulfate and sodium persulfate.

9. The elastic acrylic emulsion with high color development performance as claimed in claim 1, It is characterized in that The auxiliary agent includes an oxidant and a reducing agent, the oxidant includes at least one of sodium persulfate, hydrogen peroxide, ammonium persulfate, and tert-butyl hydroperoxide, and the reducing agent includes one of sodium pyrosulfite, sodium bisulfite, FF6, and isoascorbic acid.

10. A method for preparing the elastic acrylic emulsion with high color development performance as claimed in any one of claims 1 to 9, It is characterized in that The following steps are involved: S1. Mixing the polymerizable monomer, part of the functional monomer, part of the initiator, part of the emulsifier and part of the solvent to obtain a prepolymer solution, and dividing the prepolymer solution into a first prepolymer solution and a second prepolymer solution according to a mass ratio, wherein the mass of the first prepolymer solution is 1 to 10% of the total mass of the prepolymer solution; S2. at 70 to 88 ° C, the remaining solvent, the first prepolymer solution, the remaining emulsifier, the remaining initiator are mixed to obtain a first reaction solution, the first reaction solution is reacted at a temperature of 70 to 88 ° C for 1 to 30 minutes to obtain a second reaction solution, and then the second prepolymer solution is added dropwise to the second reaction solution at a temperature of 70 to 88 ° C for 150 to 200 minutes. After the addition is completed, the mixture is kept at 70 to 88 ° C for 1 to 1.5 hours to obtain a third reaction solution; S3. Mix the third reaction liquid with the remaining auxiliary agent at a temperature of 70 to 85° C. and keep warm for 10 to 30 minutes to obtain a fourth reaction liquid. Then, mix the fourth reaction liquid with the remaining functional monomer at a temperature of 45 to 55° C. to obtain the elastic acrylic emulsion with high color development performance.

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