High light transmittance acrylic powder resin and method for preparing the same

Abstract

The application relates to the technical field of C09D5 / 03, in particular to a high-transmittance acrylic powder resin and a preparation method thereof, raw materials for preparing the acrylic powder resin by weight percentage at least include: 80-100 parts of soft monomers, 400-600 parts of hard monomers, 0-10 parts of carboxyl functional monomers, 200-400 parts of ester functional monomers, 20-100 parts of hydroxyl functional monomers, 10-30 parts of initiators, 5-20 parts of chain transfer agents, 800-1200 parts of solvents and 1-10 parts of nano additives; the nano additives are added, and the synthesis process of the acrylic resin is optimized, so that the prepared acrylic powder resin has high transmittance and good weather resistance, and can meet the actual use requirements in the fields of automobile hubs and photovoltaics.

Description

Technical Field

[0001] This invention relates to the field of C09D5 / 03 technology, specifically to a high-transmittance acrylic powder resin and its preparation method. Background Technology

[0002] Powdered resins have received widespread attention in recent years due to their zero VOCs characteristic. Among them, polyester resins and epoxy resins are the most widely used. However, epoxy resins have poor weather resistance and are prone to discoloration. Polyester resins are easily hydrolyzed and their weather resistance is also generally poor. Polyacrylic acid resins exhibit superior weather resistance and have a designable structure, allowing for molecular chain modification to improve various properties. Currently, the demand for transparent powders is increasing in fields such as automotive wheels and photovoltaics, with increasingly higher requirements for light transmittance. Therefore, higher demands are placed on the light transmittance performance of the products.

[0003] Currently, there is relatively little research on improving the light transmittance of powdered resins themselves. Most products and processes improve light transmittance by applying a surface treatment layer after the powdered resin film has been formed. Most antireflective and antireflective coatings are based on nano-silica solutions, such as the weather-resistant multilayer antireflective film and its preparation process disclosed in Chinese patent application (publication number CN 116430486A). Firstly, the bonding between two or more layers is purely physical, and the adhesion depends entirely on the compatibility between the products. This can easily lead to failure during long-term use, increasing repair work and inevitably affecting the performance of the resin layer. Secondly, it increases the amount of coating work, while many applications require minimizing subsequent work; therefore, the impact on product performance is also significant. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a high-transmittance acrylic powder resin. By adding nano-additives and optimizing the acrylic resin synthesis process, the prepared acrylic powder resin exhibits high transmittance and good weather resistance, meeting the practical application needs in automotive wheel hubs and photovoltaic fields.

[0005] The present invention provides a high-transmittance acrylic powder resin, which, by weight, comprises at least the following raw materials: 80-100 parts of soft monomer, 400-600 parts of hard monomer, 0-10 parts of carboxyl functional monomer, 200-400 parts of ester functional monomer, 20-100 parts of hydroxyl functional monomer, 10-30 parts of initiator, 5-20 parts of chain transfer agent, 800-1200 parts of solvent, and 1-10 parts of nano-additive.

[0006] As a preferred technical solution, the raw materials for preparing the high-transmittance acrylic powder resin are composed of the following raw materials in parts by weight: 80-100 parts of soft monomer, 470-570 parts of hard monomer, 5-10 parts of carboxyl functional monomer, 250-350 parts of ester functional monomer, 40-60 parts of hydroxyl functional monomer, 15-25 parts of initiator, 5-15 parts of chain transfer agent, 800-1200 parts of solvent, and 4-6 parts of nano-additive.

[0007] Preferably, the raw materials for preparing the high-transmittance acrylic powder resin are composed of the following raw materials in parts by weight: 90 parts of soft monomer, 470 parts of hard monomer, 6 parts of carboxyl functional monomer, 300 parts of ester functional monomer, 50 parts of hydroxyl functional monomer, 20 parts of initiator, 10 parts of chain transfer agent, 1000 parts of solvent, and 5 parts of nano-additive.

[0008] As a preferred technical solution, the soft monomer is one of ethyl acrylate (EA), butyl acrylate (BA), and isooctyl acrylate (2-EHA), preferably butyl acrylate.

[0009] As a preferred technical solution, the hard monomer is a combination of methyl methacrylate (MMA) and styrene (ST), wherein the mass ratio of methyl methacrylate (MMA) to styrene (ST) is (20-45):(10-20), preferably (31-41):16.

[0010] As a preferred technical solution, the carboxyl functional monomer is acrylic acid or methacrylic acid.

[0011] As a preferred technical solution, the ester functional monomer is a combination of at least one of glycidyl methacrylate (GMA) and benzyl methacrylate, polyethylene glycol o-phenylphenyl ether acrylate, dicyclopentenyl acrylate, allyl methacrylate, and isobornyl methacrylate, preferably a combination of glycidyl methacrylate and benzyl methacrylate or isobornyl methacrylate, wherein the mass ratio of glycidyl methacrylate to benzyl methacrylate or isobornyl methacrylate is (1.5-3):1, preferably 2:1.

[0012] In this invention, by introducing butyl acrylate as a soft monomer, methyl methacrylate and styrene as hard monomers, and combining them with carboxyl functional monomers, ester functional monomers and hydroxyl functional monomers, the adhesion, impact strength and weather resistance of acrylic powder resin are guaranteed while the light transmittance of the product is improved.

[0013] As a preferred technical solution, the hydroxyl functional monomer is at least one of hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate, and hydroxypropyl acrylate.

[0014] As a preferred technical solution, the initiator is selected from at least one of tert-butyl peroxide, di-tert-butyl peroxide, di-tert-pentyl peroxide, tert-butyl hydroperoxide, and tert-butyl peroxide-3,5,5-trimethylhexanoate, preferably di-tert-pentyl peroxide (DTAP).

[0015] As a preferred technical solution, the chain transfer agent is dodecyl mercaptan or 2,4-diphenyl-4-methyl-1-pentene (AMS).

[0016] As a preferred technical solution, the solvent is selected from at least one of xylene, ethylene glycol butyl ether, ethyl acetate, solvent oil, toluene, propylene glycol methyl ether acetate, and dipropylene glycol methyl ether acetate, preferably xylene.

[0017] As a preferred technical solution, the nano-additive is selected from at least one of modified silica, nano silica, nano titanium dioxide, modified titanium dioxide, nano zirconium oxide, and modified nano zirconium oxide, preferably modified silica or modified titanium dioxide.

[0018] As a preferred technical solution, the particle size of the nano-additive is <100nm, preferably <50nm, and even more preferably 10-20nm.

[0019] As a preferred technical solution, the modified silica is prepared by adjusting the silica sol to pH=3-4, adding a silane coupling agent, stirring and dispersing, heating and keeping warm, then washing with deionized water until neutral, and centrifuging to obtain modified silica (gel-like).

[0020] As a preferred technical solution, the modified titanium dioxide is prepared by adjusting the pH of the titanium sol to 3-4, adding a silane coupling agent, stirring and dispersing, heating and keeping warm, then washing with deionized water until neutral, and centrifuging to obtain modified titanium dioxide (gel).

[0021] Another aspect of the present invention provides a method for preparing a high-transmittance acrylic powder resin, comprising at least the following steps:

[0022] (1) Add the solvent to the container according to the weight parts, heat to the reaction temperature, and then add the monomer mixture of soft monomer, hard monomer, carboxyl functional monomer, ester functional monomer and 40-90% of the total weight of initiator and 90-97.5% of the total weight of chain transfer agent dropwise to the solvent for reaction.

[0023] (2) Mix nano-additives, hydroxyl functional monomers, initiators (2-10% of total weight), and chain transfer agents (the remainder) to obtain a modified mixture.

[0024] (3) When the remaining weight of the monomer mixture is less than 40% of the total weight of the monomer mixture, start adding the modified mixture dropwise;

[0025] (4) After the modified mixture is added dropwise, keep it warm for 1-2 hours, add the remaining initiator and keep it warm for 2-3 hours, then distill under reduced pressure, crush and grind to obtain the final product.

[0026] Preferably, the reaction temperature is 110-145℃.

[0027] Preferably, the modified mixture is added 30-60 minutes after the monomer mixture is added.

[0028] In this invention, by optimizing the addition process of nano-additives, a modified mixture is first prepared by mixing nano-additives, hydroxyl functional monomers, 2-10% of the total weight of the initiator, and the remainder chain transfer agent. Then, when the remaining weight of the monomer mixture is below 40% of the total weight, the modified mixture is added dropwise. Furthermore, the addition of the modified mixture is controlled to end 30-60 minutes after the monomer mixture is added, effectively improving the product's light transmittance. The inventors believe the reason is that, through this addition process, the monomer concentration of the nano-additives gradually increases in the later stages of the reaction, making it easier to integrate into the polymer molecular chain. This allows the nano-additives and hydroxyl monomers to be mainly distributed on the membrane surface during film formation. The small-particle-size nano-additives, in conjunction with the hydroxyl functional monomers, form a water film on the membrane surface, resulting in a smooth and highly transparent film. However, mixing acrylic resin powder with nano-additive powder or simultaneously adding the nano-additives and monomer mixture does not effectively improve light transmittance.

[0029] Beneficial effects

[0030] 1. This invention provides a high-transmittance acrylic powder resin. By adding nano-additives and optimizing the acrylic resin synthesis process, the prepared acrylic powder resin has high transmittance and good weather resistance, meeting the practical application needs of automotive wheel hubs and photovoltaic fields.

[0031] 2. In this invention, by introducing butyl acrylate as a soft monomer, methyl methacrylate and styrene as hard monomers, and combining them with carboxyl functional monomers, ester functional monomers and hydroxyl functional monomers, the adhesion, impact strength and weather resistance of acrylic powder resin are guaranteed while the light transmittance of the product is improved.

[0032] 3. In this invention, by optimizing the addition process of nano-additives, 2-10% of the total weight of nano-additives, hydroxyl functional monomers, and initiators, and the remaining chain transfer agent are mixed to obtain a modified mixture. Then, when the remaining weight of the monomer mixture is less than 40% of the total weight of the monomer mixture, the modified mixture is started to be added dropwise. Furthermore, the addition of the modified mixture is controlled to end 30-60 minutes after the addition of the monomer mixture, which effectively improves the light transmittance of the product. Detailed Implementation

[0033] Examples 1-6

[0034] Examples 1-6 of the present invention provide a high light transmittance acrylic powder resin and its preparation method. The raw materials for preparation are shown in Table 1 by weight.

[0035] Table 1

[0036]

[0037]

[0038] The modified silica is prepared by adjusting the silica sol to pH 3.5 ± 0.5, adding a silane coupling agent (specifically Y171, Sanfu Chemical), stirring and dispersing, heating to 60°C and holding for 2 hours, then washing with deionized water until neutral, and centrifuging to obtain modified silica (gel-like).

[0039] The silica sol contains nano-silica particles with a particle size of 10-20 nm, specifically M3010 silica sol (Shandong Baite New Materials Co., Ltd.).

[0040] The modified titanium dioxide is prepared by adjusting the pH of the titanium sol to 3.5±0.5, adding a silane coupling agent (specifically Y171, Sanfu Chemical), stirring and dispersing, heating to 60℃ and holding for 2 hours, then washing with deionized water until neutral, and centrifuging to obtain modified titanium dioxide (gel).

[0041] The titanium sol contains nano-titanium dioxide particles with a particle size of 10 nm, specifically VK-TA33 (model) titanium sol (Xuancheng Jingrui New Materials Co., Ltd.).

[0042] The preparation method of the high-transmittance acrylic powder resin specifically includes the following steps:

[0043] (1) Add the solvent to the container according to the weight parts, heat to the reaction temperature, and then add the monomer mixture of soft monomer, hard monomer, carboxyl functional monomer, ester functional monomer and 75% of the total weight of initiator and 95% of the total weight of chain transfer agent dropwise to the solvent for reaction.

[0044] (2) Mix modified silica, hydroxyl functional monomer, 5% of the total weight of initiator, and the balance chain transfer agent to obtain a modified mixture;

[0045] (3) When the remaining weight of the monomer mixture is 20% of the total weight of the monomer mixture, start adding the modified mixture dropwise;

[0046] (4) After the modified mixture is added dropwise, keep it warm for 2 hours, add the remaining initiator and keep it warm for 3 hours, then distill under reduced pressure, crush and grind to obtain the final product.

[0047] The reaction temperature is 125°C.

[0048] The addition of the modified mixture was controlled to be completed 40 minutes after the addition of the monomer mixture.

[0049] Comparative Example 1

[0050] Comparative Example 1 of the present invention provides an acrylic powder resin and its preparation method, the specific implementation of which is the same as that of Example 3, except that the preparation method of the acrylic powder resin specifically includes the following steps:

[0051] (1) Add the solvent to the container according to the weight parts, heat to the reaction temperature, and then add the monomer mixture of soft monomer, hard monomer, carboxyl functional monomer, ester functional monomer, modified silica, hydroxy functional monomer and 80% of the total weight of the initiator and chain transfer agent dropwise to the solvent for reaction. The dropwise addition time is 5h.

[0052] (2) After the monomer mixture is added dropwise, keep it warm for 2 hours, add the remaining initiator and keep it warm for 3 hours, then distill under reduced pressure, crush and grind to obtain the final product. The reaction temperature is 125℃.

[0053] Comparative Example 2

[0054] Comparative Example 2 of the present invention provides an acrylic powder resin and its preparation method. The specific implementation method is the same as that of Example 3, except that the modified silica is replaced with nano silica (particle size > 200nm, undispersed, Fujian Zhongmin Dadi Nano New Materials Co., Ltd.). The preparation method of the acrylic powder resin specifically includes the following steps: (1) According to the weight parts, the solvent is added to the container and heated to the reaction temperature. Then, the monomer mixture of soft monomer, hard monomer, carboxyl functional monomer, ester functional monomer, hydroxy functional monomer and 80% of the total weight of the initiator and chain transfer agent is added dropwise to the solvent for reaction. The dropwise addition time is 5h.

[0055] (2) After the monomer mixture is added dropwise, keep it warm for 2 hours, add the remaining initiator and keep it warm for 3 hours. After vacuum distillation, crushing and grinding, mix it with nano-silica to obtain the final product.

[0056] The reaction temperature is 125°C.

[0057] Performance testing

[0058] The acrylic powder resin and DDDA (curing agent) prepared in the examples and comparative examples were mixed in a 1:1 molar ratio of epoxy groups to carboxyl functional groups to prepare a coating. The coating was electrostatically sprayed onto the surface of a tinplate substrate to form a 120 μm thick coating. The following weather resistance and light transmittance were tested. The test methods and results are shown in Table 2.

[0059] Table 2

[0060]

Claims

1. A high-transmittance acrylic powder resin, characterized in that, The high-transmittance acrylic powder resin is prepared from the following raw materials in parts by weight: 80-100 parts of soft monomer, 470-570 parts of hard monomer, 5-10 parts of carboxyl functional monomer, 250-350 parts of ester functional monomer, 40-60 parts of hydroxyl functional monomer, 15-25 parts of initiator, 5-15 parts of chain transfer agent, 800-1200 parts of solvent, and 4-6 parts of nano-additive; the soft monomer is butyl acrylate; the hard monomer is a combination of methyl methacrylate and styrene, wherein the mass ratio of methyl methacrylate to styrene is (20-45):(10-20); the carboxyl functional monomer is acrylic acid or methacrylic acid; the ester functional monomer is a combination of glycidyl methacrylate and benzyl methacrylate or isobornyl methacrylate, wherein the mass ratio of glycidyl methacrylate and benzyl methacrylate or isobornyl methacrylate is (1.5-3):1; the nano-additive is modified silica or modified titanium dioxide. The particle size of the nano-additive is <50 nm; The modified silica is prepared by adjusting the silica sol to pH=3-4, adding a silane coupling agent, stirring and dispersing, heating and keeping warm, then washing with deionized water until neutral, and centrifuging to obtain gel-like modified silica. The modified titanium dioxide is prepared by adjusting the pH of the titanium sol to 3-4, adding a silane coupling agent, stirring and dispersing, heating and keeping warm, then washing with deionized water until neutral, and centrifuging to obtain gel-like modified titanium dioxide. The method for preparing the high-transmittance acrylic powder resin includes at least the following steps: (1) Add the solvent to the container according to the weight parts, heat to the reaction temperature, and then add the monomer mixture of soft monomer, hard monomer, carboxyl functional monomer, ester functional monomer and 40-90% of the total weight of initiator and 90-97.5% of the total weight of chain transfer agent dropwise to the solvent for reaction. (2) Mix nano-additives, hydroxyl functional monomers, initiators (2-10% of total weight), and chain transfer agents (the remainder) to obtain a modified mixture; (3) When the remaining weight of the monomer mixture is less than 40% of the total weight of the monomer mixture, the modified mixture is added dropwise. The addition of the modified mixture is controlled to end 30-60 minutes after the addition of the monomer mixture. (4) After the modified mixture is added dropwise, keep it warm for 1-2 hours, add the remaining initiator and keep it warm for 2-3 hours, then distill under reduced pressure, crush and grind to obtain the final product.

2. The high light transmittance acrylic powder resin according to claim 1, characterized in that, The initiator is selected from at least one of tert-butyl peroxide, di-tert-butyl peroxide, di-tert-pentyl peroxide, tert-butyl hydroperoxide, and tert-butyl peroxide-3,5,5-trimethylhexanoate.

3. The high light transmittance acrylic powder resin according to claim 1, characterized in that, The solvent is selected from at least one of xylene, ethylene glycol butyl ether, ethyl acetate, solvent oil, toluene, propylene glycol methyl ether acetate, and dipropylene glycol methyl ether acetate.

4. The high light transmittance acrylic powder resin according to claim 1, characterized in that, The reaction temperature is 110-145℃.

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