Copolymerized leveling agent, preparation method thereof and application of copolymerized leveling agent in matting powder coating

Abstract

The invention relates to a copolymerized leveling agent, a preparation method thereof and application of the copolymerized leveling agent in a matting powder coating, and belongs to the technical field of coatings. The problems that in the prior art, a powder coating added with a delustering agent is poor in coating film surface effect and poor in neutral salt mist resistance are solved. The copolymerized leveling agent comprises a liquid leveling agent and active silicon dioxide in a mass ratio of (65-70): (30-35), the liquid leveling agent comprises an active matter and an initiator, and the active matter comprises the following raw materials in parts by mole: 22-28 parts of butyl acrylate, 7-11 parts of 1, 2, 3-trimethyl-1, 3-pentanediol monoisobutyrate, 1-3 parts of 1, 2, 3-trimethyl-1, 3-pentanediol monoisobutyrate, 1-3 parts of 1, 2, 3-trimethyl-1 the component A is prepared from the following components in parts by weight: 20-30 parts of 1, 2-epoxy-4-vinyl cyclohexane, 48-55 parts of xylene, 5-8 parts of triphenylethylene, 7-10 parts of decyl oleate and 3-4 parts of 3, 7-dimethyl-6-octenol butyrate; the use amount of the initiator is 3-4wt% of the mass of the butyl acrylate. When the copolymerized flatting agent is applied to the matting powder coating, matting, coating appearance and neutral salt mist resistance can be taken into account.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings, and specifically relates to a copolymer leveling agent and a preparation method and application thereof, and in particular to application of the copolymer leveling agent in matte powder coatings. Background Art

[0002] Coating is an indispensable part of the material surface processing technology. Coating appearance, decorative properties and corrosion protection are all the application purposes of coating.

[0003] With the improvement of national environmental protection standards, restrictions on volatile organic compound (VOC) emissions are becoming increasingly stringent. Powder coatings have the advantages of no VOC pollution, 100% film formation, and good comprehensive performance, and their market is growing rapidly.

[0004] Among them, the powder coatings of outdoor systems are mainly products of triglycidyl isocyanurate (TGIC) curing system. With the improvement of indoor and outdoor decorative requirements and the change of people's aesthetics, the use of low-gloss powder coatings has gradually increased. People are keen to use powder coating products with a gloss of less than 30% in decoratively differentiated spaces. The preparation of low-gloss powder coatings mainly depends on the preparation of powder coatings of matting systems. For example, matting TGIC powder coatings require additional matting agents to participate in curing. The composite matting agent product prepared by carboxyl acrylic polymer is added to the powder coating. When the carboxyl polyester resin and the curing agent TGIC are film-formed and cured, the polycarboxyl acrylic matting agent participates in the curing reaction together. The difference in curing activity and speed between the carboxyl curing agent and the polyester resin and the poor compatibility of the polyester carboxyl acrylic resin and the polyester resin are used for matting. The matting effect can be better achieved, generally reaching 15-30%. If the matting is further performed, the gloss of the coating film can reach about 10%. However, although the coating can achieve a gloss of about 10% or even less than 10%, the large amount of matting agent used and the large difference in compatibility between the matting agent and the polyester resin result in poor surface effects of the coating, such as rough surface and poor apparent fineness. The rough surface of the coating reduces the density of the coating, and the neutral salt spray resistance of the coating is difficult to meet the application requirements. This also largely limits the further application of the TGIC matting system in the low-gloss field.

[0005] Traditional leveling agents are generally polypropylene butyl ester polymers, which can adjust the surface tension of the coating and reduce the surface roughness. However, since ordinary leveling agents do not participate in the curing reaction of the coating, using them in the TGIC matting system and increasing their dosage can indeed reduce the surface roughness, but after boiling in water, the coating surface is easily sticky, and the coating is difficult to matt, and the matt effect below 10% cannot be achieved. How to achieve a balance between matt and surface effect and solve this problem has always been a difficulty in the research of matt systems. Summary of the invention

[0006] The present invention aims to solve the technical problem that, while powder coatings in the prior art that add matting agents can achieve matting effects, the surface effect of the coating film is poor and the neutral salt spray resistance is difficult to meet application requirements. A copolymer leveling agent and a preparation method thereof and application in matting powder coatings are provided.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows.

[0008] In a first aspect, the present invention provides a copolymer leveling agent, comprising a liquid leveling agent and active silicon dioxide in a mass ratio of 65-70:30-35;

[0009] The liquid leveling agent includes an active substance and an initiator. The raw materials of the active substance include, by mole,

[0010]

[0011] The amount of the initiator used is 3-4 wt% of the mass of butyl acrylate.

[0012] Preferably, the active silica is hydrophobic fumed silica.

[0013] Preferably, the initiator is dibenzoyl peroxide (BPO).

[0014] Preferably, the epoxy equivalent of the copolymerized leveling agent is 1020-1400 g / mol.

[0015] In a second aspect, the method for preparing the copolymer leveling agent of the present invention comprises the following steps:

[0016] Step 1: uniformly mix the formulated amounts of butyl acrylate, decyl oleate, 3,7-dimethyl-6-octenol butyrate, an initiator and a portion of xylene at room temperature to obtain a solution A;

[0017] Step 2: uniformly mix the formulated amount of 1,2-epoxy-4-vinylcyclohexane and a portion of xylene at room temperature to obtain a solution B;

[0018] Step 3, add the formula amount of triphenylethylene and the remaining xylene into the reaction device, stir and heat to make the triphenylethylene fully dissolved and mixed evenly, add solution A dropwise, and when solution A remains to 30%-40%, start to add solution B dropwise at the same time, and after the addition is completed, keep warm for polymerization reaction;

[0019] Step 4: sampling, detecting the content of butyl acrylate in the polymerization reaction system, and when the conversion rate of butyl acrylate reaches 98% or more, reducing the pressure under vacuum and raising the temperature to remove xylene, and obtaining a liquid leveling agent when the volatile matter of the polymerization reaction system is less than 1%;

[0020] Step 5: Physically mix and adsorb the liquid leveling agent and active silica according to the formula amount to obtain a copolymer leveling agent.

[0021] Preferably, in step 1 and step 2, the portion of xylene is one-third of the formulated amount of xylene.

[0022] Preferably, in step three, the temperature is raised to 110-115°C.

[0023] Preferably, in step 3, the dropwise addition time of solution A is controlled within 2-2.5 hours.

[0024] Preferably, in step three, solution A and solution B are added dropwise at the same time.

[0025] Preferably, in step three, the insulation temperature is 105-110°C.

[0026] Preferably, in step 4, the polymerization reaction system is detected by gas chromatography.

[0027] Preferably, in step 4, the vacuum degree of the vacuum is -0.097 MPa to -0.099 MPa.

[0028] Preferably, in step 4, the temperature is raised to 135-140°C.

[0029] Preferably, in step five, the physical mixing adsorption is carried out by placing the mixture in a high-speed stirrer and stirring at a stirring speed of 500-800 rpm.

[0030] In a third aspect, the present invention also provides the use of the copolymerized leveling agent in TGIC matte powder coatings.

[0031] The principle of the present invention is as follows: the present invention combines the molecular structures of polycarboxyl acrylic resin matting agent and polyacrylate leveling agent to develop a polyacrylic leveling agent particularly suitable for TGIC matting system. The leveling agent is obtained by copolymerizing butyl acrylate, 1,2-epoxy-4-vinylcyclohexane, toluene, triphenylethylene, decyl oleate and 3,7-dimethyl-6-octenol butyrate.

[0032] Firstly, in addition to butyl acrylate, the present invention additionally introduces 1,2-epoxy-4-vinylcyclohexane with a hydrophobic structure and an active epoxy group as a reactive monomer, and is matched with 3,7-dimethyl-6-octenol butyrate, decyl oleate and phenyl triphenylene with excellent long-chain hydrophobic performance. The copolymer leveling agent finally prepared not only has excellent hydrophobic performance itself, but also introduces a special active epoxy group to participate in the coating curing of the curing agent TGIC together with the polycarboxyl acrylic matting agent. The active epoxy group participates in the curing, which is different from the functional group of the polycarboxyl acrylic matting agent. In the curing system, not only can the amount of the curing agent TGIC be reduced, but the differentiation of the curing group is more conducive to the realization of matting. Finally, after participating in the curing in the TGIC matting system, the gloss of the coating can reach 4-8%, and the appearance of the coating is significantly improved, the surface fineness is good, and the boiling resistance and neutral salt spray resistance are also significantly improved, so that the TGIC system matting and the coating appearance and neutral salt spray resistance are taken into consideration.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The copolymer leveling agent of the present invention has excellent hydrophobic performance and good matting performance. When applied to matte powder coatings, the coating surface has good fineness, the coating gloss can reach 4-8%, and the boiling water resistance and neutral salt spray resistance are also significantly improved, achieving the balance of matting, coating appearance and neutral salt spray resistance of the matte powder coating.

[0035] The preparation method of the copolymer leveling agent of the invention is simple and easy to operate, and is suitable for large-scale continuous production. DETAILED DESCRIPTION

[0036] In order to further understand the present invention, preferred embodiments of the present invention are described below. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0037] The copolymer leveling agent of the present invention comprises a liquid leveling agent and active silicon dioxide in a mass ratio of 65-70:30-35, wherein the liquid leveling agent comprises an active substance and an initiator, and the raw materials of the active substance comprise, by mole, 22-28 parts of butyl acrylate, 7-11 parts of 1,2-epoxy-4-vinylcyclohexane, 48-55 parts of xylene, 5-8 parts of triphenylethylene, 7-10 parts of decyl oleate and 3-4 parts of 3,7-dimethyl-6-octenol butyrate; and the amount of the initiator is 3-4wt% of the mass of butyl acrylate.

[0038] In some embodiments, the copolymeric leveling agent has an appearance of white flowable powder, and an epoxy equivalent of 1020-1400 g / mol, preferably 1080-1300 g / mol.

[0039] In some embodiments, the active silica is hydrophobic fumed silica, preferably TH-8200S, purchased from Shandong Wanhua Tianhe New Materials Co., Ltd.

[0040] In some embodiments, the initiator is dibenzoyl peroxide.

[0041] The preparation method of the copolymer leveling agent of the present invention comprises the following steps:

[0042] Step 1: uniformly mix the formulated amounts of butyl acrylate, decyl oleate, 3,7-dimethyl-6-octenol butyrate, an initiator and a portion of xylene at room temperature to obtain a solution A;

[0043] Step 2: uniformly mix the formulated amount of 1,2-epoxy-4-vinylcyclohexane and a portion of xylene at room temperature to obtain a solution B;

[0044] Step 3, add the formula amount of triphenylethylene and the remaining xylene into the reaction device, stir and heat to make the triphenylethylene fully dissolved and mixed evenly, add solution A dropwise, and when solution A remains to 30%-40%, start to add solution B dropwise at the same time, and after the addition is completed, keep warm for polymerization reaction;

[0045] Step 4: sampling, detecting the content of butyl acrylate in the polymerization reaction system, and when the conversion rate of butyl acrylate reaches 98% or more, reducing the pressure under vacuum and raising the temperature to remove xylene, and obtaining a liquid leveling agent when the volatile matter of the polymerization reaction system is less than 1%;

[0046] Step 5: Physically mix and adsorb the liquid leveling agent and active silica according to the formula amount to obtain a copolymer leveling agent.

[0047] In some embodiments, solution A is pumped to a first high-level tank, solution B is pumped to a second high-level tank, the reaction device is a reactor, and solution A and solution B are pumped to the reactor through the first high-level tank and the second high-level tank, respectively, for reaction.

[0048] In some embodiments, in step 1 and step 2, the portion of xylene is one-third of the formulated amount of xylene.

[0049] In some embodiments, in step 3, the dripping time of solution A is controlled at 2-2.5 h, and preferably solution A and solution B are dripped at the same time point.

[0050] In some embodiments, in step three, the temperature is raised to 110-115°C and the insulation temperature is 105-110°C.

[0051] In some embodiments, in step 4, the polymerization reaction system is detected by gas chromatography.

[0052] In some embodiments, in step 4, the vacuum degree is -0.097 MPa to -0.099 MPa.

[0053] In some embodiments, in step 4, the temperature is raised to 135-140°C.

[0054] In some embodiments, in step five, the physical mixing adsorption is carried out by stirring in a high-speed stirrer, preferably at a stirring speed of 500-800 rpm.

[0055] The copolymer leveling agent of the present invention can be used in TGIC matte powder coatings. There is no special limitation on the formula of matte powder coatings, and the formula of existing matte powder coatings can be referred to. For example, the formula of low-gloss TGIC matte powder coatings (glossiness below 10%) includes 550 parts of polyester resin, 42 parts of curing agent TGIC, 50 parts of matting agent, 150 parts of titanium dioxide, 250 parts of matting barium (W-44HB), 18 parts of leveling agent and 2 parts of benzoin, calculated by weight. Only the copolymer leveling agent of the present invention is used to replace the leveling agent in the existing formula, and the amount of the copolymer leveling agent of the present invention is preferably 3wt%-4wt% of the amount of polyester resin.

[0056] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below in conjunction with embodiments.

[0057] In the following examples, various processes and methods not described in detail are conventional methods known in the art. Unless otherwise specified, the materials, reagents, devices, instruments, equipment, etc. used in the following examples can be obtained from commercial sources.

[0058] Example 1

[0059] The copolymer leveling agent includes a liquid leveling agent and active silica (model TH-8200S, purchased from Shandong Wanhua Tianhe New Materials Co., Ltd.) with a mass ratio of 65:35, wherein the liquid leveling agent includes an active substance and an initiator, and the raw materials of the active substance include, by mole, 22 parts of butyl acrylate, 7 parts of 1,2-epoxy-4-vinylcyclohexane, 48 parts of xylene, 5 parts of triphenylethylene, 7 parts of decyl oleate and 3 parts of 3,7-dimethyl-6-octenol butyrate; the amount of the initiator BPO is 3wt% of the mass of butyl acrylate. The copolymer leveling agent has the appearance of a white fluid powder, and the epoxy equivalent is 1261g / mol after testing.

[0060] The preparation method of the copolymer leveling agent comprises the following steps:

[0061] Step 1: uniformly mix the formulated amounts of butyl acrylate, decyl oleate, 3,7-dimethyl-6-octenol butyrate, an initiator, and one third of the formulated amount of xylene at room temperature to obtain a solution A;

[0062] Step 2: uniformly mix a formulated amount of 1,2-epoxy-4-vinylcyclohexane and one-third of a formulated amount of xylene at room temperature to obtain a solution B;

[0063] Step 3: Add the formula amount of triphenylethylene and the remaining xylene into the reaction device, stir and heat to 110°C to fully dissolve the triphenylethylene and mix evenly, add solution A dropwise, and control the addition time to 2h. When solution A remains to one third, start to add solution B at the same time. Solution A and solution B are added dropwise at the same time. After the addition is completed, keep warm at 105°C for polymerization reaction;

[0064] Step 4: sampling, using gas chromatography to detect the content of butyl acrylate in the polymerization reaction system, when the conversion rate of butyl acrylate reaches more than 98%, reducing the pressure under vacuum and raising the temperature to 135° C. to remove xylene, the vacuum degree is -0.097 MPa to -0.099 MPa, and when the volatile matter of the polymerization reaction system is less than 1%, a liquid leveling agent is obtained;

[0065] Step 5: Put the liquid leveling agent and active silicon dioxide into a high-speed mixer according to the formula amount and mix and adsorb them at a stirring speed of 550 rpm to obtain a copolymer leveling agent.

[0066] Example 2

[0067] The copolymer leveling agent includes a liquid leveling agent and active silica (model TH-8200S, purchased from Shandong Wanhua Tianhe New Materials Co., Ltd.) with a mass ratio of 68:32, wherein the liquid leveling agent includes an active substance and an initiator, and the raw materials of the active substance include, by mole, 23 parts of butyl acrylate, 9 parts of 1,2-epoxy-4-vinylcyclohexane, 50 parts of xylene, 6 parts of triphenylethylene, 8 parts of decyl oleate and 3.5 parts of 3,7-dimethyl-6-octenol butyrate; the amount of the initiator BPO is 3.5wt% of the mass of butyl acrylate. The copolymer leveling agent has the appearance of a white fluid powder, and the epoxy equivalent is 1147g / mol after testing.

[0068] The preparation method of the copolymer leveling agent comprises the following steps:

[0069] Step 1: uniformly mix the formulated amounts of butyl acrylate, decyl oleate, 3,7-dimethyl-6-octenol butyrate, an initiator, and one third of the formulated amount of xylene at room temperature to obtain a solution A;

[0070] Step 2: uniformly mix a formulated amount of 1,2-epoxy-4-vinylcyclohexane and one-third of a formulated amount of xylene at room temperature to obtain a solution B;

[0071] Step 3: Add the formula amount of triphenylethylene and the remaining xylene into the reaction device, stir and heat to 112°C to fully dissolve the triphenylethylene and mix evenly, add solution A dropwise, and control the addition time to 2.2h. When solution A remains to one third, start to add solution B at the same time. Solution A and solution B are added dropwise at the same time. After the addition is completed, keep warm at 110°C for polymerization reaction;

[0072] Step 4: sampling, using gas chromatography to detect the content of butyl acrylate in the polymerization reaction system, when the conversion rate of butyl acrylate reaches more than 98%, reducing the pressure under vacuum and raising the temperature to 135° C. to remove xylene, the vacuum degree is -0.097 MPa to -0.099 MPa, and when the volatile matter of the polymerization reaction system is less than 1%, a liquid leveling agent is obtained;

[0073] Step 5: Put the liquid leveling agent and active silicon dioxide into a high-speed mixer according to the formula amount and mix and adsorb them at a stirring speed of 720 rpm to obtain a copolymer leveling agent.

[0074] Example 3

[0075] The copolymer leveling agent includes a liquid leveling agent and active silica (model TH-8200S, purchased from Shandong Wanhua Tianhe New Materials Co., Ltd.) with a mass ratio of 66:34, wherein the liquid leveling agent includes an active substance and an initiator, and the raw materials of the active substance include, by mole, 26 parts of butyl acrylate, 9 parts of 1,2-epoxy-4-vinylcyclohexane, 52 parts of xylene, 7 parts of triphenylethylene, 9 parts of decyl oleate and 4 parts of 3,7-dimethyl-6-octenol butyrate; the amount of the initiator BPO is 4wt% of the mass of butyl acrylate. The copolymer leveling agent has the appearance of a white fluid powder, and the epoxy equivalent is 1295g / mol after testing.

[0076] The preparation method of the copolymer leveling agent comprises the following steps:

[0077] Step 1: uniformly mix the formulated amounts of butyl acrylate, decyl oleate, 3,7-dimethyl-6-octenol butyrate, an initiator, and one third of the formulated amount of xylene at room temperature to obtain a solution A;

[0078] Step 2: uniformly mix a formulated amount of 1,2-epoxy-4-vinylcyclohexane and one-third of a formulated amount of xylene at room temperature to obtain a solution B;

[0079] Step 3: Add the formula amount of triphenylethylene and the remaining xylene into the reaction device, stir and heat to 110°C to fully dissolve the triphenylethylene and mix evenly, add solution A dropwise, and control the addition time to 2.5h. When solution A remains to one third, start to add solution B at the same time. Solution A and solution B are added dropwise at the same time. After the addition is completed, keep warm at 110°C for polymerization reaction;

[0080] Step 4: sampling, using gas chromatography to detect the content of butyl acrylate in the polymerization reaction system, when the conversion rate of butyl acrylate reaches more than 98%, reducing the pressure under vacuum and raising the temperature to 140° C. to remove xylene, the vacuum degree is -0.097 MPa to -0.099 MPa, and when the volatile matter of the polymerization reaction system is less than 1%, a liquid leveling agent is obtained;

[0081] Step 5: Put the liquid leveling agent and active silicon dioxide into a high-speed mixer according to the formula amount and mix and adsorb them at a stirring speed of 685 rpm to obtain a copolymer leveling agent.

[0082] Example 4

[0083] The copolymer leveling agent includes a liquid leveling agent and active silica (model TH-8200S, purchased from Shandong Wanhua Tianhe New Materials Co., Ltd.) with a mass ratio of 70:30, wherein the liquid leveling agent includes an active substance and an initiator, and the raw materials of the active substance include, by mole, 28 parts of butyl acrylate, 11 parts of 1,2-epoxy-4-vinylcyclohexane, 55 parts of xylene, 8 parts of triphenylethylene, 10 parts of decyl oleate and 4 parts of 3,7-dimethyl-6-octenol butyrate; the amount of initiator BPO is 4wt% of the mass of butyl acrylate. The copolymer leveling agent has the appearance of a white fluid powder, and the epoxy equivalent is 1112g / mol after testing.

[0084] The preparation method of the copolymer leveling agent comprises the following steps:

[0085] Step 1: uniformly mix the formulated amounts of butyl acrylate, decyl oleate, 3,7-dimethyl-6-octenol butyrate, an initiator, and one third of the formulated amount of xylene at room temperature to obtain a solution A;

[0086] Step 2: uniformly mix a formulated amount of 1,2-epoxy-4-vinylcyclohexane and one-third of a formulated amount of xylene at room temperature to obtain a solution B;

[0087] Step 3, add the formula amount of triphenylethylene and the remaining xylene into the reaction device, stir and heat to 115°C to fully dissolve the triphenylethylene and mix evenly, add solution A dropwise, and control the addition time to 2.5h. When solution A remains to one third, start to add solution B at the same time. Solution A and solution B are added dropwise at the same time. After the addition is completed, keep warm at 110°C for polymerization reaction;

[0088] Step 4: sampling, using gas chromatography to detect the content of butyl acrylate in the polymerization reaction system, when the conversion rate of butyl acrylate reaches more than 98%, reducing the pressure under vacuum and raising the temperature to 140° C. to remove xylene, the vacuum degree is -0.097 MPa to -0.099 MPa, and when the volatile matter of the polymerization reaction system is less than 1%, a liquid leveling agent is obtained;

[0089] Step 5: Put the liquid leveling agent and active silicon dioxide into a high-speed mixer according to the formula amount and mix and adsorb them at a stirring speed of 612 rpm to obtain a copolymer leveling agent.

[0090] Comparative Example 1

[0091] A commercially available general-purpose leveling agent product is used as comparative example 1, model HL988, Huangshan Huahui Technology Co., Ltd.

[0092] Comparative Example 2

[0093] The leveling agent is the same as that in Comparative Example 1, and the amount of TGIC in the powder coating formulation is increased from 42 parts by weight to 45 parts by weight.

[0094] The performance of the products of Examples 1-4 and Comparative Examples 1-2 was tested.

[0095] The powder coatings of Examples 1-4 and Comparative Examples 1-2 were prepared using the existing low-gloss TGIC matte powder coating formula, and the formulas were as follows in parts by weight:

[0096] 550 parts of polyester resin, 42 parts of curing agent TGIC, 50 parts of matting agent, 150 parts of titanium dioxide, 250 parts of matting barium (W-44HB), 18 parts of leveling agent and 2 parts of benzoin;

[0097] Among them, the polyester resin model SJ4ET was purchased from Anhui Shenjian New Materials Co., Ltd.; the matting agent model was HM15, from Huangshan Huahui Technology Co., Ltd.; the curing agent TGIC, titanium dioxide and benzoin were all common products on the market.

[0098] Preparation of coating film: According to the above-mentioned low-gloss TGIC matte powder coating formula, the materials are mixed evenly, extruded, tableted and crushed by a twin-screw extruder, and then the obtained flakes are crushed and sieved to make powder coating; the powder coating is sprayed on the tinplate with an electrostatic spray gun, the film thickness is 80μm, and cured at 190℃ / 15min to obtain the coating film.

[0099] The coating film is tested according to GB / T 21776-2008 "Guide to Testing Standards for Powder Coatings and Their Coatings"; the leveling grade test is carried out according to the PCI leveling grading standard.

[0100] Table 1 Performance of coating films of Examples 1-4 and Comparative Examples 1-2

[0101]

[0102] As can be seen from Table 1, the products of the present invention (Example 1-Example 4) are obtained by copolymerization using a special raw material combination containing epoxy groups. The obtained leveling agent not only has excellent hydrophobic performance, but also participates in the curing reaction of the polyester resin, which reduces the amount of the curing agent TGIC. Compared with Comparative Example 2, the amount of TGIC can be reduced from 45 parts to 42 parts, reducing the cost of the powder coating. Moreover, since it participates in the curing and forming of the coating film, compared with the non-reactive ordinary leveling agent, the surface fineness of the prepared coating film is relatively excellent, and the glossiness is also relatively low, which is basically below 8%, and the leveling grade of the coating film is relatively high, all reaching above grade 6, and the performance is better in long-term boiling water (12h), and there is almost no obvious change on the surface after boiling in boiling water for 12h.

[0103] The common general-purpose leveling agent used in Comparative Example 1 has a homopolymer of butyl acrylate as its main component, which has no active epoxy group that can undergo a curing reaction with the polyester resin. Therefore, the amount of curing agent TGIC used is insufficient, and the curing is insufficient, resulting in recoil cracking and shedding of the coating after boiling in water.

[0104] In Comparative Example 2, sufficient curing can be achieved by increasing the amount of curing agent TGIC from 42 parts by weight to 45 parts by weight, but the coating film has poor surface fineness, the leveling agent grade is low, and can only reach grade 5. The performance of long-term water boiling resistance is relatively general, and obvious gloss loss and surface stickiness appear after boiling in boiling water for 12 hours.

[0105] Obviously, the above embodiments are merely examples for clear explanation, and are not intended to limit the embodiments. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A copolymer leveling agent, characterized in that: It includes a liquid leveling agent and active silicon dioxide in a mass ratio of 65-70:30-35; The liquid leveling agent includes an active substance and an initiator. The raw materials of the active substance include, by mole, The amount of the initiator used is 3-4 wt% of the mass of butyl acrylate.

2. The copolymer leveling agent according to claim 1, characterized in that The active silicon dioxide is hydrophobic fumed silicon dioxide.

3. The copolymer leveling agent according to claim 1, characterized in that The initiator is dibenzoyl peroxide.

4. The copolymer leveling agent according to claim 1, characterized in that The epoxy equivalent of the copolymer leveling agent is 1020-1400 g / mol.

5. The method for preparing a copolymer leveling agent according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: uniformly mix the formulated amounts of butyl acrylate, decyl oleate, 3,7-dimethyl-6-octenol butyrate, an initiator and a portion of xylene at room temperature to obtain a solution A; Step 2: uniformly mix the formulated amount of 1,2-epoxy-4-vinylcyclohexane and a portion of xylene at room temperature to obtain a solution B; Step 3, add the formula amount of triphenylethylene and the remaining xylene into the reaction device, stir and heat to make the triphenylethylene fully dissolved and mixed evenly, add solution A dropwise, and when solution A remains to 30%-40%, start to add solution B dropwise at the same time, and after the addition is completed, keep warm for polymerization reaction; Step 4: sampling, detecting the content of butyl acrylate in the polymerization reaction system, and when the conversion rate of butyl acrylate reaches 98% or more, reducing the pressure under vacuum and raising the temperature to remove xylene, and obtaining a liquid leveling agent when the volatile matter of the polymerization reaction system is less than 1%; Step 5: Physically mix and adsorb the liquid leveling agent and active silica according to the formula amount to obtain a copolymer leveling agent.

6. The method for preparing a copolymer leveling agent according to claim 5, characterized in that: In step 1 and step 2, the portion of xylene is respectively one-third of the formula amount of xylene.

7. The method for preparing a copolymer leveling agent according to claim 5, characterized in that: In step three, The temperature is raised to 110-115° C.; The dropwise addition time of solution A is controlled at 2-2.5h; The solution A and solution B are added dropwise at the same time point; The insulation temperature is 105-110°C.

8. The method for preparing a copolymer leveling agent according to claim 5, characterized in that: In step four, Detecting the polymerization reaction system by gas chromatography; The vacuum degree of the vacuum is -0.097Mpa to -0.099Mpa; The temperature is raised to 135-140°C.

9. The method for preparing a copolymer leveling agent according to claim 5, characterized in that: In step 5, the physical mixing adsorption method is: placing in a high-speed stirrer and stirring at a stirring speed of 500-800 rpm.

10. Use of the copolymer leveling agent according to any one of claims 1 to 4 in triglycidyl isocyanurate matte powder coating.

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