Preparation and Coating Method of UV-LED Curing F-Class Insulating Paint for Enameled Wire

Abstract

The present invention relates to a UV-LED curable F-class insulating paint for enameled wires and its preparation and coating methods, including: oligomers; diluent monomers; photoinitiators; additives. The main oligomer is organosilicon polyurethane acrylate, and another main oligomer is polyester acrylate with a special structure. The number-average molecular weight of the organosilicon-modified polyurethane acrylate is about 3000 g / mol; the polybasic acid used in the other polyester acrylate is a mixture of terephthalic acid, trimellitic anhydride, and maleic anhydride. The invention provides two kinds of insulating paints for enameled wires that can be cured by ultraviolet light and four coating processes, and finally obtains an insulating coating with good adhesion and mechanical properties, excellent sudden break and round rod winding properties, and good electrical and thermal properties on a 0.33-mm copper round wire.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of UV-LED (ultraviolet light curing) coatings, and particularly relates to a preparation and coating method of UV-LED light curing for enameled wire insulating paint. Background Art

[0002] Enameled wire insulating paint is one of the necessary conditions to ensure the normal operation of electrical equipment and occupies an important position in the field of electrical insulation. At present, the mainstream products in China are still traditional solvent-based thermosetting enameled wire insulating paints, which not only consume a large amount of heat energy, but also contain a large amount of flammable, explosive and toxic solvents such as benzene, ketones and esters. Solvents will volatilize in the construction environment, threatening human health and causing environmental pollution. Therefore, it is very important to develop new pollution-free and low-energy-consuming insulating paints, and ultraviolet light curing insulating paint is a very important direction. It has the advantages of solvent-free environmental protection, rapid curing, high production efficiency, etc., and the curing method of UV-LED has more advantages such as low heat, wide application range, low energy consumption and long service life than traditional UV mercury lamp curing, and it has received more and more attention in the research field and market application direction.

[0003] Compared with the existing technology, the present invention particularly proposes the synthesis of organosilicon-modified polyurethane acrylate and polyester acrylate. Adding organosilicon-modified polyurethane acrylate to the ultraviolet light curing insulating paint can improve the toughness of the paint film without losing the heat resistance grade, and can give full consideration to heat resistance and mechanical properties to the greatest extent. The synthesized polyester acrylate has good adhesion and heat resistance. Through two self-developed resins, combined with components such as polyurethane acrylate, pure acrylate, polyester acrylate, reactive monomer, auxiliary agent, photoinitiator, etc., two kinds of UV-LED curing enameled wire insulating paints are developed, and a 4-pass coating process plan is particularly proposed, and finally a UV-LED curing insulating paint with excellent performance and applicable to enameled wire is obtained. Summary of the Invention

[0004] In order to solve the problems of VOC emission and high energy consumption of enameled wire paint, and further improve the performance of ultraviolet light curing insulating paint for enameled wire, the present invention discloses a preparation and coating method of a new type of UV-LED light curing environmental protection insulating paint for enameled wire.

[0005] The technical solution of the present invention is: a UV-LED curing F-class insulating paint for enameled wire, comprising a UV-LED light-curable enameled wire insulating coating composition A and a composition B,

[0006] The described UV-LED light-curable enameled wire insulating coating composition A, calculated by mass parts, comprises:

[0007]

[0008]

[0009] The number-average molecular weight of the silicone-modified polyurethane acrylate is 2,500 to 3,500 g / mol, and it is formed by the reaction of hydroxy-containing acrylamide, isocyanate, silicone-modified polyol, inhibitor, and PHEA under a catalyst; the molecular weight of the silicone-modified polyol is 1,500 to 2,500 g / mol, and the catalyst is an organic bismuth compound;

[0010] The UV-LED curable enamel wire insulation coating composition B described above is composed of the following components in parts by mass:

[0011]

[0012] The polyester acrylate is a two-step reaction process. Polyester is formed by the reaction of polybasic acid, diethylene glycol, and propylene glycol under a catalyst, and then it reacts with glycidyl methacrylate under a catalyst to form polyester acrylate. The polybasic acid is a mixture of terephthalic acid, trimellitic anhydride, and maleic anhydride.

[0013] The silicone-modified polyurethane acrylate described above is composed of the following components in parts by mass:

[0014] Isocyanate: 10.5 - 16.5 parts; Hydroxy acrylamide: 7 - 8.5 parts; Silicone-modified polyol: 70 - 73 parts; Catalyst: 0.1 - 0.4 parts; Inhibitor: 0.15 - 0.5 parts, PHEA: 8 - 9 parts;

[0015] The preparation method is to slowly drop hydroxy acrylamide and inhibitor into isocyanate at a constant temperature of 45°C. After the dropping is completed, control the reaction temperature at 60 - 65°C and react for 2 h. Then add silicone-modified polyol, control the reaction temperature at 75 - 78°C, and react for 3 h. Finally, add PHEA and react for 1 h at 50 - 55°C to obtain the product.

[0016] The isocyanate is one or two of toluene diisocyanate and diphenylmethane diisocyanate.

[0017] The hydroxy acrylamide is one or several of N-hydroxyethyl acrylamide, N-hydroxyethyl methacrylamide, and N-hydroxymethyl acrylamide.

[0018] The catalyst is bismuth naphthenate; the inhibitor is p-methoxyphenol; the silicone-modified polyol is an organically modified silicone oil with a molecular weight of 2,000 g / mol; PHEA is 2-phenoxyethyl acrylate.

[0019] The polyester acrylate described above, by mass parts, is composed of: 39-55 parts of polybasic acid, 11-15 parts of diethylene glycol, 7-10 parts of propylene glycol, 0.2-0.6 parts of catalyst, 0.03-0.05 parts of inhibitor. Under the protection of nitrogen, first carry out the reaction of phthalic acid and maleic anhydride in the polybasic acid, and then carry out the reaction of trimellitic anhydride. The reaction temperature is 200°C - 220°C for 6-8 hours, and then add 18-25 parts of glycidyl methacrylate. The reaction temperature is 110°C - 120°C, and the reaction is carried out for 3 hours to obtain the reaction product.

[0020] The oligomer a described above is a product obtained by mixing phenolic epoxy acrylate and hexafluorobutyl methacrylate in a molar ratio of 9:1 and fully reacting at 55-65°C for 1 hour.

[0021] The oligomer b described above is a mixture of polyurethane acrylate and acrylate.

[0022] The auxiliary agent described above is a defoaming agent and a leveling agent, and the adhesion promoter is γ-methacryloxypropyltrimethoxysilane.

[0023] The preparation method of the UV-LED curable F-class insulating paint for enameled wire described above is to prepare the UV-LED light-curable enameled wire insulating coating compositions A and B for standby respectively.

[0024] The application of the UV-LED curable F-class insulating paint for enameled wire described above on the enameled wire. The viscosity range of the insulating paint prepared as required is 600-800 mPa.s / 40°C. The construction coating is carried out at 40-50°C, and 4 coatings are carried out in the order of the UV-LED light-curable enameled wire insulating coating composition B, composition A, composition B, and composition A, and LED curing is carried out in a nitrogen atmosphere.

[0025] Beneficial effects:

[0026] The present invention provides two kinds of ultraviolet-curable enamelled wire insulating paints and a four-coating process design scheme. The two insulating paints with different properties cured by UV-LED focus on different properties, and respectively solve the problems of adhesion, mechanical properties, and F-class electrical insulation properties and thermal properties. The composition of UV-LED photocurable enamelled wire insulating paint A or B includes: oligomers; diluent monomers; photoinitiators; and additives. Among them, the main body of the oligomers is self-developed and designed, and is combined with other oligomers such as polyurethane acrylate, epoxy acrylate, and polyester acrylate. One main body oligomer is silicone polyurethane acrylate, which is the reaction product of the following substances: hydroxy-containing acrylamide, isocyanate, silicone-modified polyol, inhibitor, and catalyst; the other main body oligomer is a polyester acrylate with a special structure, which is the reaction product of the following substances: polybasic acid, diethylene glycol, propylene glycol, glycidyl methacrylate, inhibitor, and catalyst. The number-average molecular weight of the silicone-modified polyurethane acrylate is about 3000 g / mol, and the molecular weight of the silicone-modified polyol is about 2000 g / mol; the polybasic acid used in the other self-developed polyester acrylate with a special structure is a mixture of terephthalic acid, trimellitic anhydride, and maleic anhydride. The inflection temperature of the dielectric loss reaches 145 °C, and the performance requirements of F-class enamelled wire insulating paint are fully met on copper round wire. Finally, an insulating coating with good adhesion and mechanical properties, excellent sharp break and round bar winding properties, good electrical and thermal properties is obtained on 0.33 mm copper round wire. Its thermal shock does not crack at 175 °C, the film continuity of 30 m length is 0, the number of 10 m brine pinholes is 0, the breakdown voltage can reach 8 KV, the scraping force reaches 5 N, and the softening breakdown can withstand 200 °C for 2 min without cracking.

[0027] The present invention creatively proposes a coating process design scheme for applying photocurable insulating paint on enamelled wire and UV-LED insulating paint compositions with different special structures. The synthesized novel silicone-modified polyurethane acrylate and polyester acrylate are applied in the field of photocurable enamelled wire insulating paint, which can not only solve the coating curing effect and coating uniformity performance, but also meet the performance requirements of F-class enamelled wire insulating paint through formula design. Detailed implementation mode

[0028] The preparations used in the present invention are all commercially available conventional products as long as they are qualified industrial products, and are not limited to manufacturers.

[0029] Throughout the application, the following terms have the specified meanings:

[0030] Code or Term Chinese Name 819 Phenylbis(2,4,6-trimethylbenzoyl)oxide, obtained from Ciba CN959 Polyurethane acrylate, obtained from Sartomer L-6030 Acrylate, Dongguan Sanqi Chemical Raw Materials Co., Ltd Z-6030 γ-Methacryloxypropyltrimethoxysilane obtained from Dow Corning QFX-3667 Hydroxy silicone oil obtained from Nanjing Gutian Chemical Co., Ltd PHEA 2-Phenoxyethyl acrylate, obtained from Changxing, Taiwan, China TMPTMA Trimethylolpropane triacrylate, obtained from Changxing, Taiwan, China HEMQ p-Hydroxyanisole, obtained from Ciba DMAA N,N-Dimethylacrylamide, obtained from KJ Chemical, Japan TDI / MDI Isocyanate, obtained from Bayer EM70 Isobornyl acrylate, obtained from Changxing, Taiwan, China G02 Trifluorobutyl methacrylate, obtained from Harbin Xuejia Fluorochemical EB9636 Phenolic epoxy acrylate, obtained from allnex HEAA Hydroxyethyl acrylamide, obtained from KJ Chemical, Japan CD406 Cyclohexanedimethanol diacrylate, obtained from Sartomer 6148J-75 Polyurethane acrylate, obtained from Changxing, Taiwan, China EM222 Dipropylene glycol diacrylate, obtained from Changxing, Taiwan, China TPO 2,4,6(Trimethylbenzoyl)diphenylphosphine oxide, obtained from Changxing, Taiwan, China

[0031] All are in parts by mass in the examples.

[0032] Two UV-LED photocurable coating compositions A and B for enameled wires were innovatively developed, and a four-coating process design was carried out in the order of B, A, B, A, and LED lamp curing was carried out under a nitrogen atmosphere.

[0033] The UV-LED photocurable enameled wire insulating coating composition A contains: silicone-modified polyurethane acrylate, oligomer a, reactive monomer, photoinitiator, and additives; the UV-LED photocurable enameled wire insulating coating composition B contains: polyester acrylate, oligomer b, reactive monomer, photoinitiator, and additives.

[0034] The silicone-modified polyurethane acrylate in the UV-LED photocurable enameled wire insulating coating composition A is formed by reacting hydroxy-containing acrylamide, isocyanate, silicone-modified polyol, inhibitor, under a catalyst. The number-average molecular weight of its synthetic product is about 3000 g / mol, and the molecular weight of the silicone-modified polyol is about 2000 g / mol. The catalyst is selected from organobismuth compounds such as bismuth naphthenate. Its mass fraction: isocyanate 10.5 - 16.5; hydroxy acrylamide 7 - 8.5; silicone-modified polyol 70 - 73; catalyst 0.1 - 0.4; inhibitor 0.15 - 0.5, PHEA: 8 - 9. First, heat the isocyanate to 45°C, and at a constant temperature of 45°C, slowly dropwise add hydroxy acrylamide and inhibitor. After the addition is completed, control the reaction temperature at 60 - 65°C. After reacting for 2 h, add the silicone-modified polyol and control the reaction temperature at 75 - 78°C. After reacting for 3 h, test that the NCO content is less than 1%. Add PHEA and react at 50 - 55°C for 1 h to obtain the product. The isocyanate is one or two of toluene diisocyanate and diphenylmethane diisocyanate; the hydroxy acrylamide is one or several of N-hydroxyethyl acrylamide, N-hydroxyethyl methyl acrylamide, and N-hydroxymethyl acrylamide; the silicone-modified polyol is an organically modified silicone oil with a molecular weight of about 2000 g / mol; the catalyst is selected from organobismuth compounds such as bismuth naphthenate; the inhibitor is p-methoxyphenol; PHEA is 2-phenoxyethyl acrylate.

[0035] The polyester acrylate in the UV-LED curable enameled wire insulating coating composition B is a two-step reaction. After polyesters are produced by reacting polybasic acids, diethylene glycol, and propylene glycol under a catalyst, they are then reacted with glycidyl methacrylate under a catalyst to form polyester acrylate. The polybasic acids mentioned are a mixture of terephthalic acid, trimellitic anhydride, and maleic anhydride. Calculated by mass parts, its raw material formulation composition is: polybasic acids 39-55; diethylene glycol 11-15; propylene glycol 7-10; catalyst 0.2-0.6; inhibitor 0.03-0.05. Under the condition of nitrogen protection, first react terephthalic acid and maleic anhydride, and then react trimellitic anhydride. The reaction temperature is 200°C - 220°C for 6-8 hours. Then add 18-25 of glycidyl methacrylate, and the reaction temperature is 110°C - 120°C. After reacting for 3 hours, the reaction product can be obtained.

[0036] The oligomer a mentioned is a product obtained by mixing phenolic epoxy acrylate and hexafluorobutyl methacrylate in a ratio of 9:1 and fully reacting at 55-65°C for 1 hour. The phenolic epoxy acrylate is preferably EB9636 of allnex company; the hexafluorobutyl methacrylate is preferably G02 of Harbin Xuejia Fluorochemical Co., Ltd.

[0037] The oligomer b mentioned is a mixture of polyurethane acrylate and acrylate. The characteristics of polyurethane acrylate are good adhesion and excellent toughness. It is preferably CN959 of Sartomer Chemicals. The acrylate is used to reduce shrinkage and improve the stability of adhesion. It is preferably L-6030 of Dongguan Sanqi Chemical Raw Materials Co., Ltd.

[0038] The active monomer mentioned is one or several of N,N-dimethylacrylamide, ε-caprolactone acrylate, isobornyl acrylate, dipropylene glycol diacrylate, trimethylolpropane trimethacrylate, and cyclohexanedimethanol diacrylate.

[0039] The initiator must be an initiator with ultraviolet absorption at 395nm and contains one or two of acylphosphine oxides, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide. It is preferably bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0040] The additives in the enameled wire coating combination B mentioned are adhesion promoters, defoamers, and leveling agents. The adhesion promoter is γ-methacryloxypropyltrimethoxysilane.

[0041] The additives mentioned refer to wetting agents, defoamers, and leveling agents. Wetting agents such as Tego500 and BYK378; defoamers such as BYK1790 and Tego920; leveling agents such as BYK333 and BYK3505, etc.

[0042] Example 1 Preparation of Organosilicon-Modified Polyurethane Acrylate

[0043] Synthesize the resin according to the composition of the formula in the following table

[0044]

[0045] First, heat the isocyanate to 45°C, and slowly dropwise add hydroxyacrylamide and inhibitor at a constant temperature of 45°C. After the addition is completed, control the reaction temperature at 60 - 65°C. After reacting for 2 hours, add organosilicon-modified polyol and control the reaction temperature at 75 - 78°C. After reacting for 3 hours, test that the NCO content is less than 1%. Then add PHEA and react at 50 - 55°C for 1 hour to obtain the product.

[0046] Example 2 Preparation of Polyester Acrylate

[0047] Synthesize the resin according to the composition of the formula in the following table

[0048]

[0049]

[0050] Under the condition of nitrogen protection, first add terephthalic acid, maleic anhydride, diethylene glycol, propylene glycol, and the catalyst p-toluenesulfonic acid to the reaction kettle, react at a reaction temperature of 200°C - 220°C for 5 - 6 hours, then add trimellitic anhydride, and react at 200°C - 220°C for 2 - 3 hours. Then add GMA and the catalyst, react at a reaction temperature of 110°C - 120°C, react for 3 hours and test the acid value. When the acid value < 3mgKOH / g, a light yellow viscous polyester acrylate with a molecular weight of about 4000g / mol is obtained.

[0051] Example 3 Preparation of UV-LED Curing Insulating Coating A

[0052] Prepare the coating according to the formula in the following table

[0053] A-1 A-2 A-3 1 6148J-75 30.0 2 PUA-A - 30.0 - 3 PUA-B - - 30.0 4 Oligomer a 20.0 20.0 20.0 5 DMAA 10.5 10.5 10.5 6 TMPTMA 10.0 10.0 10.0 7 EM70 8.8 8.8 8.8 8 CD406 17.2 17.2 17.2 9 TPO 2.5 2.5 2.5 10 819 0.5 0.5 0.5 11 Auxiliary agent 0.5 0.5 0.5

[0054] Among them, the oligomer a is EB9636:G02 = 9:1

[0055] Example 4 Preparation of UV-LED Curing Insulating Coating B

[0056]

[0057]

[0058] Among them, the oligomer b is CN959:L-6030 = 1:1

[0059] Example 5 Testing Methods and Results

[0060] Use round copper wire with a diameter of 0.33 mm, coat it by the die method, the thickness of the enameled wire is 20 - 30 um, cure it with an LED lamp in a nitrogen atmosphere, and coat it four times.

[0061] Process 1: B-1 → A-1 → B-1 → A-1; Process 2: B-1 → A-2 → B-1 → A-2; Process 3: B-1 → A-3 → B-1 → A-3; Process 4: B-2 → A-1 → B-2 → A-1; Process 5: B-3 → A-1 → B-3 → A-1; Process 6: B-2 → A-2 → B-2 → A-2; Process 7: B-2 → A-3 → B-2 → A-3; Process 8: B-3 → A-3 → B-3 → A-3.

[0062] Process 1 Process 2 Process 3 Process 4 Round bar winding (stretching 15%, 1D) No cracking No cracking No cracking No cracking Suddenly broken by pulling Do not lose Do not lose Do not lose Do not lose Scratch paint N 4.5 5.7 5.8 4.2 Brine pinholes in 10m length paint film 4 0 0 5 Continuity of 30m length paint film 5 0 0 7 Breakdown voltage / kV 5 8 7.8 5.6 Thermal shock at 175°C for 30 min Cracking OK OK Cracking Softening breakdown at 200°C for 2 min Cracking OK OK Cracking

[0063]

[0064]

[0065] From the above data, it can be seen that adding the self-developed and synthesized silicone polyurethane acrylate can improve the electrical and thermal properties, and the developed and synthesized polyester acrylate can improve the adhesion on copper, improve toughness, improve the paint scraping performance, and improve the electrical and thermal properties.

[0066] Finally, through the combination of two UV-LED curing insulating paints and the four-coat design, an insulating coating with good adhesion and mechanical properties, excellent sudden break and round bar winding properties, good electrical and thermal properties is obtained on a 0.33 mm copper round wire. Its thermal shock does not crack at 175 degrees, the film continuity of 30 m length is 0, the number of pinholes in 10 m brine is 0, the breakdown voltage can reach 8 KV, the scraping force reaches 5 N, and the softening breakdown can withstand 200 °C for 2 min without cracking, fully meeting the performance requirements of F-class enameled wire insulating paint.

Claims

1. Application of a UV-LED curable F-class insulating paint for enameled wire on the enameled wire, characterized in that, The insulating paint contains an enameled wire insulating coating composition A and composition B that can be cured by UV-LED light. The described UV-LED light-curable enameled wire insulating coating composition A, by mass parts, contains: 25 - 50 parts of silicone-modified polyurethane acrylate; 15 - 30 parts of oligomer a; 30 - 60 parts of reactive monomer; 1 - 5 parts of photoinitiator; 0.1 - 3 parts of auxiliary agent; The number-average molecular weight of the described silicone-modified polyurethane acrylate is 2500 - 3500 g / mol, and it is formed by the reaction of hydroxy acrylamide, isocyanate, silicone-modified polyol, inhibitor, and PHEA under a catalyst; the molecular weight of the silicone-modified polyol is 1500 - 2500 g / mol, and the catalyst is an organobism compound; The described UV-LED light-curable enameled wire insulating coating composition B, by mass parts, has the following composition: 25 - 50 parts of polyester acrylate; 15 - 40 parts of oligomer b; 30 - 55 parts of reactive monomer; 1 - 3 parts of photoinitiator; 0.5 - 2 parts of adhesion promoter 0.1 - 2 parts of auxiliary agent; The described polyester acrylate is a two-step reaction process, in which a polyester is formed by the reaction of polybasic acid, diethylene glycol, and propylene glycol under a catalyst and then reacts with glycidyl methacrylate under a catalyst to form polyester acrylate. The polybasic acid is a mixture of terephthalic acid, trimellitic anhydride, and maleic anhydride; The described oligomer a is a product obtained by mixing phenolic epoxy acrylate and hexafluorobutyl methacrylate in a molar ratio of 9:1 and fully reacting at 55 - 65 °C for 1 h; The described oligomer b is a mixture of polyurethane acrylate and polyacrylate; The viscosity range of the insulating paint prepared as required is 600 - 800 mPa·s / 40 °C. Construction coating is carried out at 40 - 50 °C, and 4 coatings are carried out in the order of UV-LED light-curable enameled wire insulating coating composition B, composition A, composition B, and composition A, and LED curing is carried out under a nitrogen atmosphere.

2. The application according to claim 1, characterized in that The described hydroxy acrylamide is one or more of N-hydroxyethyl acrylamide, N-hydroxyethyl methacrylamide, and N-hydroxymethyl acrylamide, and the isocyanate is one or two of toluene diisocyanate and diphenylmethane diisocyanate.

3. The application according to claim 1, characterized in that The catalyst is bismuth naphthenate; the inhibitor is p-methoxyphenol; the silicone-modified polyol is an organically modified silicone oil with a molecular weight of 2000 g / mol; PHEA is 2-phenoxyethyl acrylate.

4. The application according to claim 1, characterized in that The described silicone-modified polyurethane acrylate, by mass parts, has the following composition: 10.5 - 16.5 parts of isocyanate; 7 - 8.5 parts of hydroxy acrylamide; 70 - 73 parts of silicone-modified polyol; 0.1 - 0.4 parts of catalyst; 0.15 - 0.5 parts of inhibitor, and 8 - 9 parts of PHEA; The preparation method is to slowly drop hydroxyacrylamide and inhibitor into isocyanate at a constant temperature of 45°C. After the dropping is completed, the reaction temperature is controlled at 60 - 65°C. After reacting for 2 h, organosilicon-modified polyol is added, the reaction temperature is controlled at 75 - 78°C, and the reaction is carried out for 3 h. Finally, PHEA is added and the reaction is carried out for 1 h at 50 - 55°C to obtain the product.

5. The application according to claim 1, characterized in that, The polyester acrylate described above, by mass parts, is composed of: 39 - 55 parts of polybasic acid, 11 - 15 parts of diethylene glycol, 7 - 10 parts of propylene glycol, 0.2 - 0.6 parts of catalyst, 0.03 - 0.05 parts of inhibitor. Under the condition of nitrogen protection, first carry out the reaction of phthalic acid and maleic anhydride in the polybasic acid, and then carry out the reaction of trimellitic anhydride. The reaction temperature is 200°C - 220°C for 6 - 8 h, and then 18 - 25 parts of glycidyl methacrylate are added. The reaction temperature is 110°C - 120°C, and the reaction is carried out for 3 h to obtain the reaction product.

6. The application according to claim 1, characterized in that, The auxiliary agent described above is a defoaming agent and a leveling agent, and the adhesion promoter is γ-methacryloxypropyltrimethoxysilane.

7. The application according to claim 1, characterized in that, Prepare the UV-LED curable enameled wire insulation coating compositions A and B separately for standby.

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