Ultraviolet curing type transparent flame-retardant chemical coating and preparation method thereof

Abstract

The invention discloses an ultraviolet curing type transparent flame-retardant chemical coating and a preparation method thereof, and belongs to the technical field of coatings. The ultraviolet curing type transparent flame-retardant chemical coating is prepared from the following components in parts by mass: 80 parts of photosensitive resin, 4 to 6 parts of a toughening agent A, 14 to 16 parts of a toughening agent B, 4 to 6 parts of a flame retardant, 4 to 6 parts of a photoinitiator, 0.5 to 2 parts of an adhesion promoter, 0.3 to 0.5 part of a de-foaming agent, 0.06 to 0.08 part of a polymerization inhibitor and 40 to 50 parts of a diluent, epoxy acrylate is adopted as the photosensitive resin; the toughening agent A is obtained by polymerizing 2-allylsulfydryl-1, 3-benzothiazole, 4-acetyl phenyl acrylate and butyl acrylate, and the toughening agent B is obtained by polymerizing 2-allylsulfydryl-1, 3-benzothiazole, 4-acetyl phenyl acrylate and butyl acrylate; the toughening agent B adopts phenolic group terminated polydimethylsiloxane; the flame retardant is obtained by carrying out a reaction on allyl-1, 3-sultone and furyl phosphaphenanthrene.

Description

Technical Field

[0001] The invention relates to an ultraviolet curing transparent flame retardant chemical coating and a preparation method thereof. Background Art

[0002] With the rapid development of modern industry and technology, ultraviolet (UV) curing technology has been widely used in coatings, inks, adhesives and other fields due to its advantages such as high efficiency, environmental protection and energy saving. Among them, UV-curable epoxy acrylic resins are widely used in various high-performance coating materials due to their excellent adhesion, chemical resistance and good curing properties. However, although these resins perform well in terms of hardness and wear resistance, their inherent brittleness makes the coatings prone to cracking or peeling in actual applications, limiting their application on flexible substrates or in situations that require mechanical stress.

[0003] Furthermore, traditional UV-curable epoxy acrylates generally lack flame retardancy. In safety-critical applications such as electronics, aerospace, and transportation, combustion can lead to serious safety incidents.

[0004] In order to solve the above problems, the applicant has developed a UV-curable transparent flame-retardant chemical coating with excellent flame retardancy and impact toughness. Summary of the Invention

[0005] The purpose of the present invention is to provide a UV-curable transparent flame-retardant chemical coating and a preparation method thereof, so as to solve the technical problems mentioned in the above background technology.

[0006] The technical solution for achieving the purpose of the present invention is:

[0007] In the first aspect, the present invention provides a UV-curable transparent flame-retardant chemical coating, which comprises, by mass, 80 parts by mass of a photosensitive resin, 4 to 6 parts by mass of a toughener A, 14 to 16 parts by mass of a toughener B, 4 to 6 parts by mass of a flame retardant, 2 to 4 parts by mass of a photoinitiator, 0.5 to 2 parts by mass of an adhesion promoter, 0.3 to 0.5 parts by mass of a defoaming agent, 0.06 to 0.08 parts by mass of a polymerization inhibitor, and 40 to 50 parts by mass of a diluent.

[0008] The present invention effectively improves the impact toughness and flame retardant performance of a UV-curable transparent flame-retardant chemical coating by introducing a toughening agent A, a toughening agent B, and a flame retardant into a photosensitive resin.

[0009] Furthermore, the photosensitive resin is epoxy acrylate; the adhesion promoter is hydroxyethyl methacrylate phosphate; the defoaming agent is polyoxypropylene glycerol ether; the polymerization inhibitor is p-hydroxyanisole; and the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0010] Furthermore, the toughening agent A is obtained by polymerizing 2-allylmercapto-1,3-benzothiazole, 4-acetylphenyl acrylate, and butyl acrylate;

[0011] The toughening agent A of the present invention is obtained by polymerizing 2-allylmercapto-1,3-benzothiazole, 4-acetylphenyl acrylate and butyl acrylate, and can effectively improve the impact toughness of the ultraviolet-curing transparent flame-retardant chemical coating.

[0012] Furthermore, the toughening agent B is phenol-terminated polydimethylsiloxane;

[0013] The toughening agent B of the present invention adopts phenol-terminated polydimethylsiloxane, which can further enhance the impact toughness of the UV-curable transparent flame-retardant chemical coating. At the same time, the silicon in the toughening agent B can synergistically act with the flame retardant to further improve the flame retardant performance of the UV-curable transparent flame-retardant chemical coating.

[0014] Furthermore, the flame retardant is obtained by reacting propenyl-1,3-sultone with furylphosphaphenanthrene.

[0015] The flame retardant of the present invention uses propenyl-1,3-sultone and furanylphosphaphenanthrene to undergo a Diels-Alder reaction with a furan ring via an unsaturated olefin bond, and introduces a sulfonic acid ester into the furanylphosphaphenanthrene. In the early stage of combustion, the decomposition of the flame retardant releases sulfur dioxide and phosphorus-containing compounds. The non-flammable sulfur dioxide can dilute combustible volatiles and oxygen, thereby hindering further combustion of the photosensitive resin in the coating. At the same time, the phosphorus-containing compound acts as a free radical scavenger to capture highly active free radicals H· and OH·, thereby interrupting the chain reaction during the combustion process. In the condensed phase, acidic substances containing P and S elements generated by thermal oxidative degradation of the flame retardant can esterify and dehydrate the photosensitive resin in the coating, thereby promoting carbonization of the photosensitive resin to form a continuous and dense carbon layer. The carbon layer acts as a physical barrier to isolate the combustible volatiles and heat from the outside world. The flame retardant performs highly efficient flame retardancy through a dual flame retardant mechanism, including a gas phase acting as a diluent and free radical scavenger and a condensed phase that promotes the formation of a stable and dense protective layer.

[0016] In a second aspect, the present invention provides a method for preparing the UV-curable transparent flame-retardant chemical coating as described in the first aspect, comprising the following preparation steps:

[0017] (1) Weigh and prepare each raw material component according to the corresponding mass fraction;

[0018] (2) The weighed toughener A in step (1) was mixed with 8 to 10 times the mass of isopropyl acetate of the toughener A, heated to 88 to 92 ° C and stirred for 55 to 65 minutes, and then the flame retardant was added while stirring, and the addition was completed within 10 minutes. Then, the stirring reaction was continued for 12 hours. After vacuum filtration, the filter cake was washed with ether and vacuum dried at 68 to 72 ° C for 11 to 12 hours. Then, 10M sulfuric acid solution with a mass of 2 to 3 times that of the flame retardant was added, and stirred at 88 to 92 ° C for 9 to 11 hours. , removing water by rotary evaporation, then washing with ether and vacuum drying to obtain a first mixture; during the first mixing process, the thiazole in the toughening agent A reacts with the sultone in the flame retardant to form a ring-opening, and then sulfuric acid is introduced for proton exchange to form a benzothiazole ionic liquid containing a sulfonic acid group. The benzothiazole ionic liquid containing a sulfonic acid group can be adsorbed on the active sites of the coated metal substrate to form an insoluble complex with free metal ions, forming a dense complex film on the surface of the metal substrate, thereby effectively inhibiting the corrosion of the metal substrate;

[0019] (3) After the weighed photosensitive resin, diluent, and adhesion promoter in step (1) are mixed evenly, the first mixed material and toughening agent B are added and continued to be mixed evenly, and then the defoaming agent and polymerization inhibitor are added and stirred evenly; finally, the photoinitiator is added, mixed evenly, and packaged in a light-proof manner to obtain a UV-curable transparent flame-retardant chemical coating.

[0020] Furthermore, the preparation steps of the toughening agent A are as follows: under nitrogen protection, 10 parts by mass of butyl acrylate, 0.1-0.3 parts by mass of 2-allylmercapto-1,3-benzothiazole, and 3-5 parts by mass of 4-acetylphenyl acrylate are added to 80 parts by mass of xylene, stirred for 55-65 minutes, and then 0.05-0.07 parts by mass of azoisobutyronitrile are added dropwise. The mixture is stirred and reacted at 68-72° C. for 9.5-10.5 hours. After cooling to room temperature, the xylene is removed by rotary evaporation and dried under reduced pressure to obtain a toughening agent.

[0021] Furthermore, the preparation steps of the flame retardant are as follows: 1 part by mass of furanylphosphaphenanthrene is mixed with 49 to 51 parts by mass of toluene, stirred at 1200 to 1800 r / min for 50 to 70 minutes, heated to 115 to 125° C., and then 0.96 to 1.2 parts by mass of propenyl-1,3-sultone are added within 120 minutes, and the stirring reaction is continued for 3.5 to 4.5 hours. The toluene is then removed by distillation under reduced pressure and dried to obtain a flame retardant.

[0022] Furthermore, the preparation route of the furylphosphaphenanthrene is as follows:

[0023]

[0024] Furthermore, the UV-curable transparent flame-retardant chemical coating is uniformly coated on the surface of the coated substrate and then sequentially subjected to light curing and heat treatment steps.

[0025] Furthermore, the light source for the photocuring is a high-pressure mercury lamp with a linear density of 1000 W / cm, and the irradiation time is 5 to 10 seconds; the heat treatment temperature is 115 to 125° C., and the heat treatment time is 5 to 7 hours.

[0026] After coating, the UV-curable transparent flame-retardant chemical coating of the present invention is not only light-cured but also heat-treated. During the heat treatment, the benzothiazole ionic liquid containing a sulfonic acid group and having a Bronsted acid structure in the UV-curable transparent flame-retardant chemical coating catalyzes a ketone-phenol condensation reaction between the phenol on the toughening agent B and the toughening agent A, acetylbenzene, thereby increasing the crosslinking density of the UV-curable transparent flame-retardant chemical layer and further enhancing the hardness and corrosion resistance of the UV-curable transparent flame-retardant chemical coating.

[0027] By adopting the above technical solution, the present invention has the following beneficial effects:

[0028] (1) The present invention effectively improves the impact toughness and flame retardant properties of the UV-curable transparent flame-retardant chemical coating by introducing toughening agent A, toughening agent B, and flame retardant into the photosensitive resin.

[0029] (2) The toughening agent A of the present invention is obtained by polymerization of 2-allylmercapto-1,3-benzothiazole, 4-acetylphenyl acrylate, and butyl acrylate, which can effectively improve the impact toughness of the UV-curable transparent flame-retardant chemical coating.

[0030] (3) The toughening agent B of the present invention adopts phenol-terminated polydimethylsiloxane, which can further enhance the impact toughness of the UV-curable transparent flame-retardant chemical coating. At the same time, the silicon in the toughening agent B can synergistically act with the flame retardant to further enhance the flame retardant properties of the UV-curable transparent flame-retardant chemical coating.

[0031] (4) The flame retardant of the present invention adopts propenyl-1,3-sulfonic acid lactone and furanylphosphaphenanthrene to react with the furan ring through the unsaturated olefin bond to introduce sulfonic acid ester into the furanylphosphaphenanthrene. In the early stage of combustion, the decomposition of the flame retardant will release sulfur dioxide and phosphorus-containing compounds. The non-flammable sulfur dioxide can dilute the combustible volatiles and oxygen, thereby hindering the further combustion of the photosensitive resin in the coating; at the same time, the phosphorus-containing compounds act as free radical scavengers to capture highly active free radicals H· and OH·, thereby interrupting the chain reaction in the combustion process; in the condensed phase, the acid substances containing P and S elements produced by the thermal oxidation degradation of the flame retardant can esterify and dehydrate the photosensitive resin in the coating, thereby promoting the carbonization of the photosensitive resin to form a continuous and dense carbon layer. The carbon layer acts as a physical barrier to isolate the combustible volatiles and heat from the outside world. The flame retardant has a dual flame retardant mechanism, including a gas phase as a diluent and free radical scavenger and a condensed phase that promotes the formation of a stable and dense protective layer, to achieve high-efficiency flame retardancy.

[0032] (5) During the preparation of the UV-curable transparent flame-retardant chemical coating of the present invention, the toughening agent A and the flame retardant are first mixed for the first time. During the first mixing process, the thiazole in the toughening agent A reacts with the sultone in the flame retardant to form a ring-opening, and then sulfuric acid is introduced for proton exchange to form a benzothiazole ionic liquid containing a sulfonic acid group. The benzothiazole ionic liquid containing a sulfonic acid group can be adsorbed on the active sites of the coated metal substrate to form an insoluble complex with free metal ions, forming a dense complex film on the surface of the metal substrate, thereby effectively inhibiting the corrosion of the metal substrate.

[0033] (6) After the UV-curable transparent flame-retardant chemical coating of the present invention is applied, it is not only photocured but also heat-treated. During the heat treatment, the phenol on the toughening agent B, which is a sulfonic acid group-containing benzothiazole ionic liquid catalyzed by the Brønsted acid structure in the UV-curable transparent flame-retardant chemical coating, undergoes a ketone-phenol condensation reaction with the toughening agent A, acetylbenzene, thereby increasing the crosslinking density of the UV-curable transparent flame-retardant chemical layer, thereby further enhancing the hardness and corrosion resistance of the UV-curable transparent flame-retardant chemical coating. DETAILED DESCRIPTION

[0034] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with specific implementation methods.

[0035] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0036] The following examples are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0037] The photosensitive resin used was epoxy acrylate, purchased from Taiwan Changxing Chemical Co., Ltd.

[0038] The adhesion promoter uses hydroxyethyl methacrylate phosphate;

[0039] The diluent is trimethylolpropane triacrylate;

[0040] The defoaming agent is polyoxypropylene glycerol ether;

[0041] The polymerization inhibitor is p-hydroxyanisole;

[0042] The photoinitiator used is 2-hydroxy-2-methyl-1-phenyl-1-propanone;

[0043] The phenol-terminated polydimethylsiloxane used was IOTA28729 from Anhui Aiyota Silicone Oil Co., Ltd.

[0044] The reference literature of furanylphosphaphenanthrene is "Tang Gang, Tao Yi, Deng Dan, et al. Synthesis of furanylphosphaphenanthrene flame retardant and its application in flame-retardant epoxy resin [J]. Journal of Chemistry in Universities, 2024, 45(4): 45-53. DOI: 10.7503 / cjcu20230494."; its preparation path is as follows:

[0045]

[0046] (Example 1)

[0047] A method for preparing a UV-curable transparent flame-retardant chemical coating comprises the following steps:

[0048] (1) Weigh and prepare the raw material components according to the following mass parts: 80 parts by mass of photosensitive resin, 4 parts by mass of toughening agent A, 16 parts by mass of toughening agent B, 4 parts by mass of flame retardant, 2 parts by mass of photoinitiator, 0.5 parts by mass of adhesion promoter, 0.3 parts by mass of defoaming agent, 0.06 parts by mass of polymerization inhibitor, and 40 parts by mass of diluent;

[0049] (2) The weighed toughener A in step (1) was mixed with isopropyl acetate in an amount 8 times the mass of the toughener A, heated to 88°C and stirred for 55 minutes, and then the flame retardant was added while stirring, and the addition was completed within 10 minutes. The mixture was then stirred and reacted for 12 hours. After vacuum filtration, the filter cake was washed with ether and vacuum dried at 68°C for 11 hours. Then, a 10M sulfuric acid solution in an amount 2 times the mass of the flame retardant was added, and the mixture was stirred at 88°C for 9 hours. The water was removed by rotary evaporation, and the mixture was washed with ether and vacuum dried to obtain a first mixture;

[0050] (3) After the weighed photosensitive resin, diluent, and adhesion promoter in step (1) are mixed evenly, the first mixed material and toughening agent B are added and continued to be mixed evenly, and then the defoaming agent and polymerization inhibitor are added and stirred evenly; finally, the photoinitiator is added, mixed evenly, and packaged in a light-proof manner to obtain a UV-curable transparent flame-retardant chemical coating.

[0051] The toughening agent A is prepared as follows: under nitrogen protection, 10 parts by mass of butyl acrylate, 0.1 parts by mass of 2-allylmercapto-1,3-benzothiazole, and 3 parts by mass of 4-acetylphenyl acrylate are added to 80 parts by mass of xylene, and the mixture is stirred for 55 minutes, and then 0.05 parts by mass of azoisobutyronitrile is added dropwise. The mixture is stirred and reacted at 68° C. for 9.5 hours. After cooling to room temperature, the xylene is removed by rotary evaporation, and the mixture is dried under reduced pressure to obtain the toughening agent.

[0052] The flame retardant is prepared as follows: 1 part by mass of furanylphosphaphenanthrene and 49 parts by mass of toluene are mixed, stirred at 1200 r / min for 50 minutes, heated to 115° C., and then 0.96 parts by mass of propenyl-1,3-sultone are added within 120 minutes. The stirring reaction is continued for 3.5 hours, and then the toluene is removed by distillation under reduced pressure and dried to obtain the flame retardant.

[0053] Usage method: evenly apply the UV-curable transparent flame-retardant chemical coating on the surface of the coated substrate to form a 35μm thick coating, irradiate with a high-pressure mercury lamp with a linear density of 1000W / cm for 10s at a distance of 10cm from the coating, and then heat treat at 115°C for 5.5h.

[0054] (Example 2)

[0055] A method for preparing a UV-curable transparent flame-retardant chemical coating comprises the following steps:

[0056] (1) Weigh the raw material components according to the following weight parts: 80 parts by weight of photosensitive resin, 5 parts by weight of toughening agent A, 15 parts by weight of toughening agent B, 5 parts by weight of flame retardant, 3 parts by weight of photoinitiator, 1.5 parts by weight of adhesion promoter, 0.4 parts by weight of defoaming agent, 0.07 parts by weight of polymerization inhibitor, and 45 parts by weight of diluent;

[0057] (2) The weighed toughener A in step (1) was mixed with isopropyl acetate (9 times the mass of toughener A), heated to 90° C. and stirred for 60 min, and then the flame retardant was added while stirring, and the addition was completed within 10 min. The mixture was then stirred and reacted for 12 h. After vacuum filtration, the filter cake was washed with ether and vacuum dried at 70° C. for 12 h. Then, a 10 M sulfuric acid solution (2.5 times the mass of the flame retardant) was added, stirred at 90° C. for 10 h, and water was removed by rotary evaporation. The mixture was then washed with ether and vacuum dried to obtain a first mixture;

[0058] (3) After the weighed photosensitive resin, diluent, and adhesion promoter in step (1) are mixed evenly, the first mixed material and toughening agent B are added and continued to be mixed evenly, and then the defoaming agent and polymerization inhibitor are added and stirred evenly; finally, the photoinitiator is added, mixed evenly, and packaged in a light-proof manner to obtain a UV-curable transparent flame-retardant chemical coating.

[0059] The toughening agent A is prepared as follows: under nitrogen protection, 10 parts by mass of butyl acrylate, 0.2 parts by mass of 2-allylmercapto-1,3-benzothiazole, and 3 to 5 parts by mass of 4-acetylphenyl acrylate are added to 80 parts by mass of xylene, and the mixture is stirred for 60 minutes, and then 0.06 parts by mass of azoisobutyronitrile is added dropwise. The mixture is stirred and reacted at 70° C. for 10 hours. After cooling to room temperature, the xylene is removed by rotary evaporation, and the mixture is dried under reduced pressure to obtain the toughening agent.

[0060] The flame retardant is prepared as follows: 1 part by mass of furanylphosphaphenanthrene and 50 parts by mass of toluene are mixed, stirred at 1500 r / min for 60 minutes, heated to 120° C., and then 1.1 parts by mass of propenyl-1,3-sultone are added within 120 minutes. The stirring reaction is continued for 4 hours, and then the toluene is removed by distillation under reduced pressure and dried to obtain the flame retardant.

[0061] Usage method: evenly apply the UV-curable transparent flame-retardant chemical coating on the surface of the coated substrate to form a 35μm thick coating, irradiate with a high-pressure mercury lamp with a linear density of 1000W / cm for 10s at a distance of 10cm from the coating, and then heat treat at 120℃ for 6h.

[0062] (Example 3)

[0063] A method for preparing a UV-curable transparent flame-retardant chemical coating comprises the following steps:

[0064] (1) Weigh the raw material components according to the following weight parts: 80 parts by weight of photosensitive resin, 6 parts by weight of toughening agent A, 14 parts by weight of toughening agent B, 6 parts by weight of flame retardant, 4 parts by weight of photoinitiator, 2 parts by weight of adhesion promoter, 0.5 parts by weight of defoaming agent, 0.08 parts by weight of polymerization inhibitor, and 50 parts by weight of diluent;

[0065] (2) The weighed toughener A in step (1) was mixed with isopropyl acetate in an amount 10 times the mass of the toughener A, heated to 92° C. and stirred for 65 min, and then the flame retardant was added while stirring, and the addition was completed within 10 min, and then the stirring reaction was continued for 12 h. After vacuum filtration, the filter cake was washed with ether and vacuum dried at 72° C. for 12 h, and then a 10 M sulfuric acid solution in an amount 3 times the mass of the flame retardant was added, stirred at 92° C. for 11 h, and water was removed by rotary evaporation, and then washed with ether and vacuum dried to obtain a first mixture;

[0066] (3) After the weighed photosensitive resin, diluent, and adhesion promoter in step (1) are mixed evenly, the first mixed material and toughening agent B are added and continued to be mixed evenly, and then the defoaming agent and polymerization inhibitor are added and stirred evenly; finally, the photoinitiator is added, mixed evenly, and packaged in a light-proof manner to obtain a UV-curable transparent flame-retardant chemical coating.

[0067] The toughening agent A is prepared as follows: under nitrogen protection, 10 parts by mass of butyl acrylate, 0.3 parts by mass of 2-allylmercapto-1,3-benzothiazole, and 3 to 5 parts by mass of 4-acetylphenyl acrylate are added to 80 parts by mass of xylene, and the mixture is stirred for 65 minutes, and then 0.07 parts by mass of azoisobutyronitrile is added dropwise. The mixture is stirred and reacted at 72° C. for 10.5 hours. After cooling to room temperature, the xylene is removed by rotary evaporation, and the mixture is dried under reduced pressure to obtain the toughening agent.

[0068] The flame retardant is prepared as follows: 1 part by mass of furanylphosphaphenanthrene and 51 parts by mass of toluene are mixed, stirred at 1800 r / min for 70 minutes, heated to 125° C., and then 1.2 parts by mass of propenyl-1,3-sultone are added within 120 minutes. The stirring reaction is continued for 4.5 hours, and then the toluene is removed by distillation under reduced pressure and dried to obtain the flame retardant.

[0069] Usage method: evenly apply the UV-curable transparent flame-retardant chemical coating on the surface of the coated substrate to form a 35μm thick coating, irradiate with a high-pressure mercury lamp with a linear density of 1000W / cm for 10s at a distance of 10cm from the coating, and then heat treat at 125℃ for 6.5h.

[0070] (Comparative Example 1)

[0071] The difference between Comparative Example 1 and Example 2 is that the raw material components of the UV-curable transparent flame-retardant chemical coating are as follows: 80 parts by mass of photosensitive resin, 20 parts by mass of toughening agent B, 5 parts by mass of flame retardant, 3 parts by mass of photoinitiator, 1.5 parts by mass of adhesion promoter, 0.4 parts by mass of defoaming agent, 0.07 parts by mass of polymerization inhibitor, and 45 parts by mass of diluent; the remaining components and steps are the same as those in Example 2.

[0072] (Comparative Example 2)

[0073] The difference between Comparative Example 2 and Example 2 is that the raw material components of the UV-curing transparent flame-retardant chemical coating are as follows in parts by mass: 80 parts by mass of photosensitive resin, 20 parts by mass of toughening agent A, 5 parts by mass of flame retardant, 3 parts by mass of photoinitiator, 1.5 parts by mass of adhesion promoter, 0.4 parts by mass of defoaming agent, 0.07 parts by mass of polymerization inhibitor, and 45 parts by mass of diluent; the remaining components and steps are the same as those in Example 2.

[0074] (Comparative Example 3)

[0075] The difference between Comparative Example 3 and Example 2 is that the toughening agent A is polybutyl acrylate; the other components and steps are the same as those in Example 2.

[0076] (Comparative Example 4)

[0077] The difference between Comparative Example 4 and Example 2 is that the toughening agent B is polydimethylsilane; the other components and steps are the same as those in Example 2.

[0078] (Comparative Example 5)

[0079] The difference between Comparative Example 5 and Example 2 is that only furanylphosphaphenanthrene is used as the flame retardant; the other components and steps are the same as those in Example 2.

[0080] (Comparative Example 6)

[0081] The difference between Comparative Example 6 and Example 2 is that the first mixing treatment of step (2) is not performed during the preparation of the UV-curing transparent flame-retardant chemical coating. The photosensitive resin, diluent, and adhesion promoter weighed in step (1) are directly mixed evenly, and then toughening agent A and toughening agent B are added and continued to be mixed evenly. Then, flame retardant, defoaming agent, and polymerization inhibitor are added and stirred evenly; finally, photoinitiator is added, mixed evenly, and packaged in a light-proof manner to obtain the UV-curing transparent flame-retardant chemical coating; the remaining components and steps are the same as those in Example 2.

[0082] (Comparative Example 7)

[0083] The difference between Comparative Example 7 and Example 2 is that after the UV-curable transparent flame-retardant chemical coating is applied, only light curing and 24-hour environmental curing are performed without heat treatment; the remaining components and steps are the same as those in Example 2.

[0084] (Effect Example)

[0085] Table 1 below shows the test results of various properties of the UV-curable transparent flame-retardant chemical coatings prepared in Examples and Comparative Examples:

[0086] Table 1

[0087]

[0088]

[0089] It can be seen from Table 1 above that the UV-curable transparent flame-retardant chemical coatings prepared in Examples 1 to 3 have good adhesion, corrosion resistance, impact toughness, flame retardancy, and high hardness.

[0090] The difference between Comparative Example 1 and Example 2 is that the UV-curable transparent flame-retardant chemical coating only uses toughener B without adding toughener A; compared with Comparative Example 1, the UV-curable transparent flame-retardant chemical coating prepared in Example 2 has better corrosion resistance and flame retardancy and higher hardness. The improvement in impact toughness in Comparative Example 1 may be due to the increase in flexible polydimethylsilane molecular chains.

[0091] The difference between Comparative Example 2 and Example 2 is that the UV-curable transparent flame-retardant chemical coating only uses toughener A without adding toughener B; compared with Comparative Example 2, the UV-curable transparent flame-retardant chemical coating prepared in Example 2 has better corrosion resistance, impact toughness, flame retardancy, and higher hardness.

[0092] The difference between Comparative Example 3 and Example 2 is that the toughening agent A uses polybutyl acrylate instead of the toughening agent A obtained by polymerization of 2-allylmercapto-1,3-benzothiazole, 4-acetylphenyl acrylate, and butyl acrylate. The presence of polybutyl acrylate makes; compared with Example 2 and Comparative Example 3, the UV-curable transparent flame-retardant chemical coating prepared in Example 2 has better adhesion, corrosion resistance, and flame retardancy, and higher hardness. The improvement in impact toughness in Comparative Example 3 may be caused by the reduction of rigid rings in toughening agent A.

[0093] The difference between Comparative Example 4 and Example 2 is that the toughening agent B uses polydimethylsilane instead of phenol-terminated polydimethylsiloxane; compared with Example 2 and Comparative Example 4, the UV-curable transparent flame-retardant chemical coating prepared in Example 2 has better adhesion and corrosion resistance and higher hardness.

[0094] The difference between Comparative Example 5 and Example 2 is that the flame retardant uses only furanylphosphaphenanthrene instead of the flame retardant obtained by reacting propenyl-1,3-sultone and furanylphosphaphenanthrene. Compared with Comparative Example 5, the UV-curable transparent flame-retardant chemical coating prepared in Example 2 has higher corrosion resistance, impact toughness and hardness.

[0095] The difference between Comparative Example 6 and Example 2 is that the first mixing treatment of step (2) is not performed during the preparation of the UV-curing transparent flame-retardant chemical coating. Compared with Comparative Example 5, the UV-curing transparent flame-retardant chemical coating prepared in Example 2 has higher corrosion resistance, impact toughness and hardness.

[0096] The difference between Comparative Example 7 and Example 2 is that after the UV-curing transparent flame-retardant chemical coating is applied, only light curing and 24 hours of environmental curing are performed, and no heat treatment is performed; compared with Comparative Example 5, the UV-curing transparent flame-retardant chemical coating prepared in Example 2 has better adhesion, corrosion resistance, impact toughness, flame retardancy, and higher hardness.

[0097] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A UV-curable transparent flame-retardant chemical coating, characterized in that: Calculated by mass, it includes 80 parts by mass of photosensitive resin, 4 to 6 parts by mass of toughening agent A, 14 to 16 parts by mass of toughening agent B, 4 to 6 parts by mass of flame retardant, 2 to 4 parts by mass of photoinitiator, 0.5 to 2 parts by mass of adhesion promoter, 0.3 to 0.5 parts by mass of defoaming agent, 0.06 to 0.08 parts by mass of polymerization inhibitor, and 40 to 50 parts by mass of diluent.

2. The UV-curable transparent flame-retardant chemical coating according to claim 1, characterized in that: The photosensitive resin is epoxy acrylate.

3. The UV-curable transparent flame-retardant chemical coating according to claim 1, characterized in that: The toughening agent A is obtained by polymerizing 2-allylmercapto-1,3-benzothiazole, 4-acetylphenyl acrylate, and butyl acrylate; and the toughening agent B is obtained by using phenol-terminated polydimethylsiloxane.

4. The UV-curable transparent flame-retardant chemical coating according to claim 1, characterized in that: The flame retardant is obtained by reacting propenyl-1,3-sultone with furylphosphaphenanthrene.

5. A method for preparing the UV-curable transparent flame-retardant chemical coating according to claims 1 to 4, characterized in that: The method comprises the following preparation steps: (1) Weigh and prepare each raw material component according to the corresponding mass fraction; (2) The weighed toughener A in step (1) is mixed with 8 to 10 times the mass of isopropyl acetate of the toughener A, heated to 88 to 92° C. and stirred for 55 to 65 minutes, and then the flame retardant is added while stirring, and the addition is completed within 10 minutes, and then the stirring reaction is continued for 12 hours. After vacuum filtration, the filter cake is washed with ether and vacuum dried at 68 to 72° C. for 11 to 12 hours, and then 10M sulfuric acid solution with a mass of 2 to 3 times that of the flame retardant is added, stirred at 88 to 92° C. for 9 to 11 hours, and water is removed by rotary evaporation, and then washed with ether and vacuum dried to obtain a first mixture; (3) After the weighed photosensitive resin, diluent, and adhesion promoter in step (1) are mixed evenly, the first mixed material and toughening agent B are added and continued to be mixed evenly, and then the defoaming agent and polymerization inhibitor are added and stirred evenly; finally, the photoinitiator is added, mixed evenly, and packaged in a light-proof manner to obtain a UV-curable transparent flame-retardant chemical coating.

6. The method for preparing the UV-curable flame-retardant chemical coating according to claim 5, characterized in that: The toughening agent A is prepared as follows: under nitrogen protection, 10 parts by mass of butyl acrylate, 0.1-0.3 parts by mass of 2-allylmercapto-1,3-benzothiazole, and 3-5 parts by mass of 4-acetylphenyl acrylate are added to 80 parts by mass of xylene, and the mixture is stirred for 55-65 minutes, and then 0.05-0.07 parts by mass of azoisobutyronitrile is added dropwise. The mixture is stirred and reacted at 68-72° C. for 9.5-10.5 hours. After cooling to room temperature, the xylene is removed by rotary evaporation, and the mixture is dried under reduced pressure to obtain the toughening agent.

7. The method for preparing the UV-curable transparent flame-retardant chemical coating according to claim 5, characterized in that: The flame retardant is prepared by the following steps: mixing 1 part by mass of furanylphosphaphenanthrene with 49 to 51 parts by mass of toluene, stirring at 1200 to 1800 r / min for 50 to 70 minutes, heating to 115 to 125° C., adding 0.96 to 1.2 parts by mass of propenyl-1,3-sultone within 120 minutes, continuing to stir and react for 3.5 to 4.5 hours, then removing the toluene by distillation under reduced pressure, and drying to obtain the flame retardant.

8. The method for preparing the UV-curable transparent flame-retardant chemical coating according to claim 5, characterized in that: The preparation process of the furylphosphaphenanthrene is as follows:

9. The method for preparing the UV-curable transparent flame-retardant chemical coating according to claim 5, characterized in that: The ultraviolet curing transparent flame retardant chemical coating is uniformly coated on the surface of the coated substrate and then sequentially subjected to light curing and heat treatment steps.

10. The method for preparing the UV-curable transparent flame-retardant chemical coating according to claim 9, characterized in that: The light source for the photocuring is a high-pressure mercury lamp with a linear density of 1000 W / cm, and the irradiation time is 5 to 10 seconds; the heat treatment temperature is 115 to 125° C., and the heat treatment time is 5 to 7 hours.

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