High-temperature-resistant acrylic coating and preparation method thereof

Abstract

The invention belongs to the technical field of coatings, and particularly provides a high-temperature-resistant acrylic-based coating and a preparation method thereof. The coating is prepared from the following raw materials: 40-60 parts of modified acrylic resin, 7-12 parts of polyurethane resin, 4-7 parts of modified calcium carbonate, 3-7 parts of cellulose ester resin, 3-5 parts of a mold pressing aid, 0.5-1 part of a silane coupling agent, 1-3 parts of a curing agent, 0.05-0.2 part of a defoaming agent, 20-40 parts of deionized water and 3-8 parts of an organic solvent. The coating disclosed by the invention has the characteristics of good high-temperature resistance, good mold pressing effect and no floating of patterns.

Description

Technical Field

[0001] The present invention belongs to the technical field of coatings, and particularly relates to a high-temperature resistant acrylic-based coating and a preparation method thereof. Background Art

[0002] Acrylic-based coatings have excellent adhesion, impact resistance, etc., and play an important role in the coating industry. In the field of modern industrial manufacturing, the demand for coatings that can maintain stable performance in high-temperature environments is increasing. At the same time, the molding effect of coatings is directly related to the aesthetics and recognition of products. Therefore, it is crucial to develop coatings that are both high-temperature resistant and have good molding effects.

[0003] Chinese Patent CN 112143293 A discloses a laser coating and its preparation method and application. By weight, the laser coating includes the following components: 40-45 parts of aqueous acrylic resin emulsion, 6-8 parts of film-forming aid, 2-3 parts of defoamer, 20-25 parts of modified laser aluminum silver paste, 10-20 parts of deionized water. This laser coating has good light resistance, strong adhesion, stable structure, and bright and stable laser color. However, it only uses a single aqueous acrylic resin emulsion, and its high-temperature resistance may be insufficient, and it will show the phenomenon of hot stickiness and cold brittleness when the temperature changes, affecting the molding effect.

[0004] Therefore, it is urgent to develop a high-temperature resistant acrylic-based coating with good molding effect at the same time. Summary of the Invention

[0005] Aiming at the existing technical problems, the purpose of the present invention is to provide a high-temperature resistant acrylic-based coating and a preparation method thereof. The coating of the present invention has good high-temperature resistance, good molding effect and no pattern blooming, and has a good market prospect.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present invention is as follows:

[0007] On the one hand, the present invention provides a high-temperature resistant acrylic-based coating. By weight, the following raw materials are included for preparing the coating: 40-60 parts of modified acrylic resin, 7-12 parts of polyurethane resin, 4-7 parts of modified calcium carbonate, 3-7 parts of cellulose ester resin, 3-5 parts of molding aid, 0.5-1 part of silane coupling agent, 1-3 parts of curing agent, 0.05-0.2 part of defoamer, 20-30 parts of deionized water, and 3-8 parts of organic solvent.

[0008] The reaction mechanism and function of the present invention are as follows:

[0009] 1. The present invention first synthesizes a heat-resistant acrylic monomer as a functional monomer, introducing a heat-resistant diphenyl sulfone structure into the molecular chain of the acrylic resin to form a rigid structure with high symmetry and high regularity. The free rotation of the molecular chain is affected by the increased rigid structure, making it difficult for the molecular configuration to change, which can effectively improve the heat resistance of the coating and exhibit a higher thermal decomposition temperature. Secondly, different acrylic monomers have different properties. The applicant can effectively improve the water resistance and flexibility of the coating by introducing acrylic acid, 2-ethylhexyl acrylate, styrene, and the heat-resistant acrylic monomer and controlling the mass ratio of the four, avoiding cracking of the coating during the molding process and reducing the molding bright solid temperature to a certain extent.

[0010] 2. The leveling property and coating performance of acrylic resin are relatively good, but it will show the phenomenon of hot stickiness and cold brittleness when the temperature changes, and it is not very suitable for being used alone as a molding laser coating. Polyurethane resin usually has a linear molecular structure and has the advantages of good film-forming property, easy crystallization, good temperature resistance, and peelability, but the softening point range is relatively wide, and the phenomena of incomplete pressing and non-realization occur during molding, so it is not suitable for being used alone as a molding laser coating either. The present invention mixes the modified acrylic resin and polyurethane resin in a specific ratio to make the molding effect of the coating good.

[0011] 3. Calcium carbonate is a commonly used filler, which can not only improve the high-temperature resistance, but also improve the fluidity of the molding material, reduce the shrinkage rate of the molded product, and improve the surface smoothness of the product. However, simple physical mixing may lead to poor dispersibility and contactability during the adsorption process, thus affecting the molding effect.

[0012] In the present invention, phytic acid is used to preliminarily modify calcium carbonate. By activating and adjusting the surface properties of calcium carbonate, its adhesion to the coating system and coating substrate is enhanced, the interlayer adhesion is enhanced, and the coating is not easy to migrate. Then, sodium bis(1,3-dimethylbutyl) sulfosuccinate and dodecylpyridinium chloride are introduced to modify the surface of calcium carbonate particles based on hydrogen bonds and van der Waals forces, making calcium carbonate have a higher reflectivity, thereby improving the gloss of the coating and making the coating have good surface and visual effects. Further, a silane coupling agent is added to modify calcium carbonate to make its dispersibility good, which is beneficial to its curing cross-linking reaction with epoxy resin, so as to chemically bond the modified calcium carbonate to the molecular chain of the acrylic resin, enhancing the interfacial bonding strength and dispersibility between the two, making the modified calcium carbonate play a good reinforcing role, and further improving the high-temperature resistance and molding effect of the coating.

[0013] 4. The present invention enables the obtained coating to have excellent pressure-resistant blooming performance through the mutual compatibility of various components, and there will be no pattern blooming phenomenon. First, calcium carbonate, as a filler, can be bonded to the molecular chain of acrylic resin after modification, improving its dispersibility and enhancing the interfacial bonding strength between the two. Second, the modified acrylic resin, polyurethane resin and curing agent cooperate synergistically with each other, improving the heat resistance and crosslinking density, and further making the coating have good stability and migration resistance. Third, cellulose ester resin can be used as an adhesion enhancer to improve the stability and adhesion of the coating. Fourth, additives such as molding aids, silane coupling agents and defoamers can not only improve the adhesion between the coating and the substrate, but also contribute to the film formation of the coating, enabling the coating to migrate to the surface during the coating drying process to form a single molecular film, balancing the surface tension, and further reducing the migration phenomenon and pattern blooming problem during aluminizing.

[0014] In some embodiments, the preparation method of the modified acrylic resin comprises the following steps:

[0015] S1. Mix 4,4'-sulfonyldibenzoyl chloride, 2-chloro-4-fluoro-5-nitrophenol and toluene, stir, add pyridine, stir and react for 5-6 h, rotary evaporate, and separate by column chromatography to obtain an intermediate;

[0016] S2. Mix the intermediate obtained in step S1, hydroxyethyl acrylate and toluene, stir, heat to 65-85 °C, stir and react for 6-9 h, rotary evaporate, and separate by column chromatography. The obtained product is then subjected to nitration reaction to obtain a heat-resistant acrylic monomer;

[0017] S3. Mix acrylic acid, 2-ethylhexyl acrylate, styrene, the heat-resistant acrylic monomer obtained in step S2 and a solvent, stir to obtain a mixed solution for standby; mix an initiator and a solvent, stir to obtain a liquid for standby;

[0018] S4. Add a solvent to a reaction kettle, introduce an inert gas, heat to 90-110 °C, dropwise add the mixed solution obtained in step S3, then dropwise add the liquid obtained in step S3, stir and react for 6-8 h, and cool to obtain a modified acrylic resin.

[0019] In some embodiments, the molar ratio of 4,4'-sulfonyldibenzoyl chloride to 2-chloro-4-fluoro-5-nitrophenol in step S1 is 1:(2.05-2.4).

[0020] In some embodiments, the mass ratio of acrylic acid, 2-ethylhexyl acrylate, styrene and the heat-resistant acrylic monomer in step S3 is 1:(0.4-0.7):(0.15-0.35):(0.08-0.18).

[0021] In some embodiments, the mass ratio of pyridine to 4,4'-sulfonyldibenzoyl chloride in step S1 is (0.55 - 0.7):1.

[0022] In some embodiments, the molar ratio of the intermediate to hydroxyethyl acrylate in step S2 is 1:(2.05 - 2.3).

[0023] In some embodiments, the method for preparing the modified calcium carbonate comprises the following steps:

[0024] T1. Add nano light calcium carbonate into a phytic acid aqueous solution with a concentration of 0.7 - 1 mol / L, heat to 55 - 65 °C, stir for 30 - 60 min, keep warm and stand for 0.5 - 1 h, filter, and dry to obtain pretreated particles;

[0025] T2. Mix sodium bis(1,3-dimethylbutyl) sulfosuccinate, dodecylpyridinium chloride, and water, stir, add the pretreated particles obtained in step T1 thereto, stir for 10 - 20 min, and dry to obtain a solid;

[0026] T3. Mix the solid obtained in step T2 with absolute ethanol, perform ultrasonic dispersion treatment, add a silane coupling agent, perform centrifugal separation, wash, and dry to obtain the modified calcium carbonate.

[0027] In some embodiments, the mass ratio of sodium bis(1,3-dimethylbutyl) sulfosuccinate, dodecylpyridinium chloride to the pretreated particles in step T2 is 1:(1 - 1.2):(150 - 250).

[0028] In some embodiments, the mass ratio of the solid to the silane coupling agent in step T3 is 1:(0.15 - 0.25).

[0029] In some embodiments, the dosage ratio of the nano light calcium carbonate to the phytic acid aqueous solution in step T1 is 1 g:(2.8 - 3.4) mL.

[0030] In some embodiments, the molding aid is selected from polyether-modified polyorganosiloxane molding aids and / or polyester-modified polyorganosiloxane molding aids.

[0031] In some embodiments, the curing agent is a mixture of an amino resin curing agent and a flexible epoxy resin curing agent.

[0032] Preferably, the mass ratio of the amino resin curing agent to the flexible epoxy resin curing agent is (2 - 2.8):1.

[0033] Preferably, the amino resin curing agent is any one or more of hexa-methoxyetherified amino resin, tetra-methoxyetherified amino resin, butyl etherified amino resin, and phenyl amino resin.

[0034] In some embodiments, the cellulose ester resin is any one or more of cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate.

[0035] In some embodiments, the defoamer is an organosilicon defoamer.

[0036] On the other hand, the present invention provides a method for preparing a heat-resistant acrylic-based coating, comprising the following steps:

[0037] Mix a modified acrylic resin, a polyurethane resin, a modified calcium carbonate, a cellulose ester resin, a molding aid, a silane coupling agent, a curing agent, a defoamer, deionized water, and an organic solvent to obtain a coating.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] 1. The coating of the present invention has excellent high-temperature resistance, good molding effect, clear laser pattern and no pattern blooming, and has a good market prospect.

[0040] 2. The present invention introduces a heat-resistant diphenyl sulfone structure into the molecular chain of the acrylic resin to form a rigid structure, which can effectively improve the heat resistance of the coating and make it exhibit a higher thermal decomposition temperature.

[0041] 3. By introducing acrylic acid, 2-ethylhexyl acrylate, styrene, and a heat-resistant acrylic monomer and controlling the mass ratio of the four, the present invention can effectively improve the water resistance and flexibility of the coating, and further improve the molding effect.

[0042] 4. The present invention uses phytic acid, sodium bis(1,3-dimethylbutyl) sulfosuccinate, dodecylpyridinium chloride, and a silane coupling agent to jointly modify to form a modified calcium carbonate, which not only enhances the interlayer adhesion, but also can improve the gloss of the coating, making the coating have a good visual effect. In addition, the modified calcium carbonate has good dispersibility and plays a good strengthening role, overall improving the high-temperature resistance and molding effect of the coating.

[0043] 5. Through the mutual compatibility of each component, the obtained coating of the present invention has excellent pressure blooming resistance, good stability and migration resistance of the coating, and no pattern blooming phenomenon will occur. Specific Embodiments

[0044] The following will illustrate the present invention in conjunction with specific implementation schemes. It should be noted that the following examples are examples of the present invention, only for illustrating the present invention, and not for limiting the present invention. Without departing from the gist or scope of the present invention, other combinations and various improvements within the concept of the present invention can be made.

[0045] Prepare each coating according to the proportion of each raw material and the production method specified in the following examples and comparative examples.

[0046] To facilitate those skilled in the art to implement the present invention, the manufacturers of some raw materials in the examples and comparative examples are described as follows:

[0047] Polyurethane resin, acrylic resin: purchased from Anhui Femtosecond Chemical Co., Ltd.;

[0048] Polyether-modified polyorganosiloxane: purchased from Guangzhou Yihua Digital Technology Co., Ltd., model BYK-333;

[0049] Butylated amino resin: purchased from Foshan Wengkal Trading Co., Ltd., model CYMEL1158;

[0050] Flexible epoxy resin: purchased from Langfang Hongdong Environmental Protection Technology Co., Ltd., model HYSZ27;

[0051] Cellulose acetate: purchased from Dongguan Huazhiyuan Chemical Co., Ltd., model CA-398-30;

[0052] For other raw materials without special instructions, they can all be purchased from the market.

[0053] Preparation Example 1

[0054] The preparation method of modified acrylic resin A comprises the following steps:

[0055] S1. Mix 0.1 mol of 4,4'-sulfonyldibenzoyl chloride, 0.22 mol of 2-chloro-4-fluoro-5-nitrophenol, and 600 mL of toluene, stir for 1 h, add 21.8 g of pyridine, stir and react for 6 h, perform rotary evaporation, column chromatography separation, and gradient elution with a mixed solution of ethyl acetate and petroleum ether with a volume ratio of 1:1 to obtain an intermediate;

[0056] S2. Mix 0.05 mol of the intermediate obtained in step S1, 0.11 mol of hydroxyethyl acrylate, and 500 mL of toluene, stir for 1 h, heat to 75 °C, stir and react for 8 h, perform rotary evaporation, column chromatography separation, and gradient elution with a mixed solution of ethyl acetate and petroleum ether with a volume ratio of 1:1 to obtain a product. Mix 30 mL of 4 wt% hydrochloric acid aqueous solution and 10.5 g of iron powder, add the obtained 25 g of product and 200 mL of absolute ethanol under ice bath conditions at 0 °C, stir and react for 4 h, extract with dichloromethane, perform rotary evaporation on the organic phase, column chromatography separation, and gradient elution with a mixed solution of ethyl acetate and petroleum ether with a volume ratio of 1:1 to obtain a heat-resistant acrylic monomer;

[0057] S3. Mix 100 g of acrylic acid, 55 g of 2-ethylhexyl acrylate, 25 g of styrene, 13 g of the heat-resistant acrylic monomer obtained in step S2, and 200 mL of butyl acetate, and stir for 2 h to obtain a mixed solution for standby; mix 2.5 g of benzoyl peroxide and 50 mL of butyl acetate, and stir for 20 min to obtain a liquid for standby.

[0058] S4. Add 60 mL of butyl acetate to the reaction kettle, introduce nitrogen, heat to 100 °C, dropwise add the mixed solution obtained in step S3, and then dropwise add the liquid obtained in step S3, stir and react for 7 h, and cool to room temperature to obtain modified acrylic resin A.

[0059] Preparation Example 2

[0060] A preparation method of modified acrylic resin B, comprising the following steps:

[0061] S1. Mix 100 g of acrylic acid, 55 g of 2-ethylhexyl acrylate, 25 g of styrene, and 200 mL of butyl acetate, and stir for 2 h to obtain a mixed solution for standby; mix 2.5 g of benzoyl peroxide and 50 mL of butyl acetate, and stir for 20 min to obtain a liquid for standby.

[0062] S2. Add 60 mL of butyl acetate to the reaction kettle, introduce nitrogen, heat to 100 °C, dropwise add the mixed solution obtained in step S1, and then dropwise add the liquid obtained in step S1, stir and react for 7 h, and cool to room temperature to obtain modified acrylic resin B.

[0063] Preparation Example 3

[0064] The preparation method of modified acrylic resin C is the same as that of Preparation Example 1, except that the addition amount of 2-chloro-4-fluoro-5-nitrophenol in step S1 is 0.18 mol.

[0065] Preparation Example 4

[0066] The preparation method of modified acrylic resin D is the same as that of Preparation Example 1, except that 155 g of acrylic acid is added in step S3 instead of 100 g of acrylic acid and 55 g of 2-ethylhexyl acrylate.

[0067] Preparation Example 5

[0068] The preparation method of modified acrylic resin E is the same as that of Preparation Example 1, except that the addition amount of 2-ethylhexyl acrylate in step S3 is 35 g.

[0069] Preparation Example 6

[0070] A preparation method of modified calcium carbonate A, comprising the following steps:

[0071] T1. Add 100 g of nano light calcium carbonate to 300 mL of 0.8 mol / L phytic acid aqueous solution, heat to 60 °C, stir for 45 min, keep warm and stand for 1 h, filter, and dry to constant weight at 80 °C to obtain pretreated particles;

[0072] T2. Mix 0.2 g of sodium bis(1,3-dimethylbutanol) sulfosuccinate, 0.2 g of dodecylpyridinium chloride, and 200 mL of water, stir for 30 min, add 40 g of the pretreated particles obtained in step T1 thereto, stir for 15 min, and dry to constant weight at 80 °C to obtain a solid;

[0073] T3. Mix 20 g of the solid obtained in step T2 with 600 mL of absolute ethanol, perform ultrasonic dispersion treatment for 30 min, add 4 g of silane coupling agent KH-550, perform centrifugal separation, wash 3 times with absolute ethanol, and dry to constant weight at 80 °C to obtain modified calcium carbonate A.

[0074] Preparation Example 7

[0075] The preparation method of modified calcium carbonate B is the same as that of Preparation Example 6, except that the addition amount of the pretreated particles described in step T2 is 67.5 g.

[0076] Preparation Example 8

[0077] The preparation method of modified calcium carbonate C is the same as that of Preparation Example 6, except that the addition amount of the silane coupling agent KH-550 described in step T3 is 2.4 g.

[0078] Example 1

[0079] A heat-resistant acrylic-based coating, by weight, the following raw materials are included in the preparation of the coating: 50 parts of modified acrylic resin A, 9.5 parts of polyurethane resin, 5.5 parts of modified calcium carbonate A, 5 parts of cellulose acetate, 4 parts of polyether-modified polyorganosiloxane BYK-333, 0.75 part of silane coupling agent KH550, 2 parts of curing agent, 0.125 part of organosilicon defoamer BYK-065, 30 parts of deionized water, 5.5 parts of isopropanol; wherein,

[0080] The curing agent is a mixture of butylated amino resin and flexible epoxy resin, and the mass ratio of the two is 2.4:1.

[0081] The preparation method of the coating in this example includes the following steps:

[0082] Mix modified acrylic resin A, polyurethane resin, modified calcium carbonate A, cellulose acetate, polyether-modified polyorganosiloxane BYK-333, silane coupling agent KH550, curing agent, organosilicon defoamer BYK-065, deionized water, and isopropanol, and stir for 3 h to obtain the coating.

[0083] Example 2

[0084] A heat-resistant acrylic-based coating. By weight, the following raw materials are included for preparing the coating: 40 parts of modified acrylic resin A, 7 parts of polyurethane resin, 4 parts of modified calcium carbonate A, 3 parts of cellulose acetate, 3 parts of polyether-modified polyorganosiloxane BYK-325, 0.5 part of silane coupling agent KH550, 1 part of curing agent, 0.05 part of organosilicon defoamer BYK-065, 20 parts of deionized water, and 3 parts of isopropanol; wherein,

[0085] The curing agent is a mixture of butylated amino resin and flexible epoxy resin, and the mass ratio of the two is 2:1.

[0086] The preparation method of the coating in this example is the same as that in Example 1.

[0087] Example 3

[0088] A heat-resistant acrylic-based coating. By weight, the following raw materials are included for preparing the coating: 60 parts of modified acrylic resin A, 12 parts of polyurethane resin, 7 parts of modified calcium carbonate A, 7 parts of cellulose acetate, 5 parts of polyether-modified polyorganosiloxane BYK-325, 1 part of silane coupling agent KH550, 3 parts of curing agent, 0.2 part of organosilicon defoamer BYK-065, 40 parts of deionized water, and 8 parts of isopropanol; wherein,

[0089] The curing agent is a mixture of butylated amino resin and flexible epoxy resin, and the mass ratio of the two is 2.8:1.

[0090] The preparation method of the coating in this example is the same as that in Example 1.

[0091] Example 4

[0092] A heat-resistant acrylic-based coating and its preparation method. The specific implementation method is the same as that in Example 1, except that an equal amount of modified acrylic resin B is used to replace modified acrylic resin A.

[0093] Example 5

[0094] A heat-resistant acrylic-based coating and its preparation method. The specific implementation method is the same as that in Example 1, except that an equal amount of modified acrylic resin C is used to replace modified acrylic resin A.

[0095] Example 6

[0096] A heat-resistant acrylic-based coating and its preparation method. The specific implementation method is the same as that in Example 1, except that an equal amount of modified acrylic resin D is used to replace modified acrylic resin A.

[0097] Example 7

[0098] A heat-resistant acrylic-based coating and its preparation method. The specific implementation is the same as that of Example 1, except that an equal amount of modified acrylic resin E is used to replace modified acrylic resin A.

[0099] Example 8

[0100] A heat-resistant acrylic-based coating and its preparation method. The specific implementation is the same as that of Example 1, except that an equal amount of modified calcium carbonate B is used to replace modified calcium carbonate A.

[0101] Example 9

[0102] A heat-resistant acrylic-based coating and its preparation method. The specific implementation is the same as that of Example 1, except that an equal amount of modified calcium carbonate C is used to replace modified calcium carbonate A.

[0103] Comparative Example 1

[0104] A heat-resistant acrylic-based coating and its preparation method. The specific implementation is the same as that of Example 1, except that an equal amount of commercially available acrylic resin is used to replace modified acrylic resin A.

[0105] Comparative Example 2

[0106] A heat-resistant acrylic-based coating and its preparation method. The specific implementation is the same as that of Example 1, except that an equal amount of commercially available calcium carbonate is used to replace modified calcium carbonate A.

[0107] Effect evaluation:

[0108] The coatings prepared in Examples 1-9 and Comparative Examples 1-2 above were tested and analyzed. The specific results are shown in Table 1.

[0109] First, the following processing operations were performed on the coatings:

[0110] ① Coating: The coating was diluted with water to form a coating with a solid content of 18 wt%. The substrate was a 15-μm PET film. Coating was carried out on a Kawakami coater at room temperature. The 16-meter oven had 6 sections, and the temperatures were set at 85°C, 120°C, 135°C, 145°C, 150°C, and 110°C. The machine speed was 100 m / min, and the dry coating amount was controlled within the range of 1.2 ± 0.1 g / m 2 to form a laser coating;

[0111] ② Embossing: Embossing was carried out using a Shantou Yiming single-plate single-press embossing machine at temperatures of 150°C and 180°C, a pressure of 0.3 MPa, and a machine speed of 25 m / min;

[0112] ③ Evaporation coating: Subsequently, ZnS medium was vacuum-evaporated to form a laser film with metallic luster.

[0113] Performance testing:

[0114] (1) High-temperature resistance test: Place the prepared laser film in an oven and evaluate it after being at a high temperature of 220 °C for 12 h. The evaluation method is to observe the peeling of the aluminum layer and the laser coating. It is excellent if there is no aluminum peeling and the coating is completely not peeled off from the PET. It is good if there is slight aluminum peeling or peeling. It is poor if there is a large amount of aluminum peeling or peeling. + and - represent their excellent and good grades.

[0115] (2) Embossing performance: Observe the temperature of embossing bright and real, and at the same time use a X-Rite XP-62 color difference meter to measure its L value at an embossing temperature of 150 °C to characterize the embossing brightness.

[0116] Table 1

[0117]

[0118]

[0119] From the results in Table 1, it can be seen that the coatings prepared in Examples 1-3 not only have high-temperature resistance but also have good embossing effects.

[0120] Compared with Example 1, in Examples 4-7 and Comparative Example 1, when preparing the acrylic resin, in Example 4, the heat-resistant acrylic monomer was not added, reducing the heat resistance. In Example 5, the molar ratio of 4,4'-sulfonyldibenzoyl chloride and 2-chloro-4-fluoro-5-nitrophenol was changed, and the rigid structure was poor, both of which would make the high-temperature resistance of the coating worse. In Example 6, the type of acrylic monomer was changed, and in Example 7, the mass ratio of acrylic acid, 2-ethylhexyl acrylate, styrene, and heat-resistant acrylic monomer was changed, all of which would affect the embossing effect of the coating. In Comparative Example 1, an equal amount of commercially available acrylic resin was used to replace the modified acrylic resin A, resulting in poor high-temperature resistance and embossing effect of the coating.

[0121] Compared with Example 1, in Example 8, when preparing the modified calcium carbonate, the mass ratio of sodium bis(1,3-dimethylbutyl) sulfosuccinate, dodecylpyridinium chloride, and the pretreated particles was changed, resulting in a decrease in the reflectivity of the calcium carbonate surface, affecting the high-temperature resistance performance and embossing brightness of the coating. In Example 9, when preparing the modified calcium carbonate, the mass ratio of the solid and the silane coupling agent was changed. In Comparative Example 2, an equal amount of commercially available calcium carbonate was used to replace the modified calcium carbonate A, with poor dispersibility, and thus would affect the high-temperature resistance and embossing effect of the coating.

[0122] (3) Pressure-resistant flower performance test: Coat the coatings prepared in Examples 1-3 on the surface of the PET film according to the above operations, emboss the coating at an embossing temperature of 180 °C, then vacuum aluminize, transfer the coating to the cardboard with glue, conduct relevant performance tests on the transferred cardboard, and press the surface of the coating at room temperature with a pressure of 25 kg for one week to observe the changes in the coating.

[0123] It was found through testing that the coatings prepared in Examples 1-3 did not show any pattern blooming phenomenon.

[0124] As described above, it is only the preferred embodiment of the present invention, and it does not impose any form of limitation on this application. Although this application is disclosed as the preferred embodiment above, it is not intended to limit this application. Any person skilled in the art, without departing from the scope of the technical solution of this application, making some changes or modifications using the disclosed technical content above is equivalent to equivalent implementation cases. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution.

Claims

1. A heat-resistant acrylic-based coating, characterized in that, By weight parts, the raw materials for preparing the coating include: 40-60 parts of modified acrylic resin, 7-12 parts of polyurethane resin, 4-7 parts of modified calcium carbonate, 3-7 parts of cellulose ester resin, 3-5 parts of molding aid, 0.5-1 part of silane coupling agent, 1-3 parts of curing agent, 0.05-0.2 part of defoaming agent, 20-40 parts of deionized water, and 3-8 parts of organic solvent.

2. The heat-resistant acrylic-based coating according to claim 1, characterized in that, The preparation method of the modified acrylic resin comprises the following steps: S1. Mix 4,4'-sulfonyldibenzoyl chloride, 2-chloro-4-fluoro-5-nitrophenol, and toluene, stir, add pyridine, stir and react for 5-6 h, perform rotary evaporation, and separate by column chromatography to obtain an intermediate. S2. Mix the intermediate obtained in step S1, hydroxyethyl acrylate, and toluene, stir, heat to 65-85 °C, stir and react for 6-9 h, perform rotary evaporation, and separate by column chromatography. The obtained product is then subjected to nitration reaction to obtain a heat-resistant acrylic monomer. S3. Mix acrylic acid, 2-ethylhexyl acrylate, styrene, the heat-resistant acrylic monomer obtained in step S2, and a solvent, stir to obtain a mixed solution for standby; mix an initiator and a solvent, stir to obtain a liquid for standby. S4. Add a solvent to a reaction kettle, introduce an inert gas, heat to 90-110 °C, dropwise add the mixed solution obtained in step S3, then dropwise add the liquid obtained in step S3, stir and react for 6-8 h, and cool to obtain a modified acrylic resin.

3. The heat-resistant acrylic-based coating according to claim 2, wherein In step S1, the molar ratio of 4,4'-sulfonyldibenzoyl chloride to 2-chloro-4-fluoro-5-nitrophenol is 1:(2.05-2.4).

4. The heat-resistant acrylic-based coating according to claim 2, wherein, In step S3, the mass ratio of acrylic acid, 2-ethylhexyl acrylate, styrene, and the heat-resistant acrylic monomer is 1: (0.4-0.7)：(0.15-0.35)：(0.08-0.18)。 5. A heat-resistant acrylic-based coating according to claim 1, characterized in that, The preparation method of the modified calcium carbonate comprises the following steps: T1. Add nano light calcium carbonate to a 0.7-1 mol / L phytic acid aqueous solution, heat to 55-65 °C, stir for 30-60 min, keep warm and stand for 0.5-1 h, filter, and dry to obtain pretreated particles. T2. Mix sodium bis(1,3-dimethylbutyl) sulfosuccinate, dodecylpyridinium chloride, and water, stir, add the pretreated particles obtained in step T1 thereto, stir for 10-20 min, and dry to obtain a solid. T3. Mix the solid obtained in step T2 with absolute ethanol, perform ultrasonic dispersion treatment, add a silane coupling agent, perform centrifugal separation, wash, and dry to obtain modified calcium carbonate.

6. The heat-resistant acrylic-based coating according to claim 5, characterized in that, In step T2, the mass ratio of sodium bis(1,3-dimethylbutyl) sulfosuccinate, dodecylpyridinium chloride, and the pretreated particles is 1:(1-1.2):(150-250).

7. A heat-resistant acrylic-based coating according to claim 5, characterized in that, In step T3, the mass ratio of the solid to the silane coupling agent is 1:(0.15-0.25).

8. A heat-resistant acrylic-based coating according to claim 1, characterized in that, The molding aid is selected from polyether-modified polyorganosiloxane molding aids and / or polyester-modified polyorganosiloxane molding aids.

9. A heat-resistant acrylic-based coating according to claim 1, wherein, The curing agent is a mixture of an amino resin curing agent and a flexible epoxy resin curing agent.

10. A method for preparing a heat-resistant acrylic-based coating according to any one of claims 1-9, characterized in that, Comprises the following steps: Mix the modified acrylic resin, polyurethane resin, modified calcium carbonate, cellulose ester resin, molding aid, silane coupling agent, curing agent, defoamer, deionized water, and organic solvent, and stir to obtain the coating.

Images