A transparent phosphorus-containing photocured flame-retardant coating layer and a preparation method and application thereof

Abstract

The present application relates to a kind of transparent phosphorus-containing photocuring flame-retardant coating and its preparation method and application, including the following components: phosphorus-containing polyurethane acrylate, polyurethane acrylate, polyurethane organic silicon prepolymer containing double bond, nitrogen-containing acrylic monomer, phosphorus flame retardant A, phosphorus flame retardant B, silica sol, active diluent B, silane coupling agent, other auxiliary agent.The coating of the present application has adhesion, flame retardancy, weather resistance, and can be directly cured by UV on lightweight flexible photovoltaic module panel and back panel, to achieve the effect of transparent fireproofing, flame retardant, weather resistance.

Description

Technical Field

[0001] This invention belongs to the field of lightweight flexible component technology, and specifically relates to a transparent phosphorus-containing photocurable flame-retardant coating, its preparation method, and its application. Background Technology

[0002] Lightweight flexible components, with a bending radius of about 0.5m, are easy to produce in customized sizes and are widely used in building and outdoor products. Since these products are mostly installed on building surfaces and are bonded with adhesives, their flame retardancy requirement is UL790 C level. However, in the event of a fire, the components may become flammable materials, which greatly limits the application of lightweight flexible components in the construction field.

[0003] CN108384403B uses a core-shell structured nano-silica / zinc stannate flame-retardant epoxy acrylic coating with UV-cured epoxy acrylic, which can significantly reduce smoke density to achieve UL-94 V-0. However, its transparency is poor and it is not suitable for use in transparent coatings.

[0004] CN111718641B uses P-Si synergistic flame retardancy. Qi-mixed alcohol phosphate can be used as a carbon source. After promoting carbonization, it can significantly increase the carbonization of the material and achieve excellent flame retardant effect. However, its structure has poor heat resistance and is not suitable for long-term outdoor use.

[0005] The flame-retardant coating prepared by adjusting the ratio of P and N in CN113603864B has good transparency, high crosslinking density, and high thermal stability. However, the synthesized main chain structure is complex, the volume is large, the reaction degree of large functional groups is low, and there are many end group residues, which cannot meet the requirements for long-term outdoor use. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a transparent phosphorus-containing photocurable flame retardant coating, its preparation method and application. The coating has adhesion, flame retardancy and weather resistance, and can be directly cured on the panel and back of a lightweight flexible photovoltaic module by UV curing to achieve the effects of transparency, fireproofing, flame retardancy and weather resistance.

[0007] This invention provides a transparent phosphorus-containing photocurable flame-retardant coating, comprising the following components by weight:

[0008] 20-60 parts of phosphorus-containing polyurethane acrylate;

[0009] 30-40 parts of polyurethane acrylate;

[0010] 1-3 parts of polyurethane silicone prepolymer containing double bonds;

[0011] 3-6 parts of nitrogen-containing acrylic acid monomer;

[0012] Phosphorus-based flame retardant A: 5-10 parts;

[0013] 2-4 parts of phosphorus-based flame retardant B;

[0014] 1-3 parts silica sol;

[0015] Reactive diluent B: 3-9 parts;

[0016] 0.2~0.6 parts of silane coupling agent;

[0017] Other auxiliary agents: 3-10 parts;

[0018] The phosphorus-containing polyurethane acrylate is prepared from bisphenol A diglycidyl ether, phosphate ester, isocyanate, polymerization inhibitor, catalyst, hydroxy acrylate, and reactive diluent A.

[0019] Preferably, the phosphate ester includes one or more of dibutyl phosphate, trimethylolpropane phosphate, and triphenyl phosphate.

[0020] Preferably, the isocyanate includes one or more of toluene diisocyanate, isophorone diisocyanate, and hexanediolmethane diisocyanate.

[0021] Preferably, the polymerization inhibitor is hydroquinone.

[0022] Preferably, the catalyst comprises one or more of dibutyltin dilaurate and stannous octoate.

[0023] Preferably, the hydroxyacrylate includes one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, and hydroxybutyl 4-acrylate.

[0024] Preferably, the reactive diluent A comprises one or more of tripropylene glycol diacrylate, dipropylene glycol diacrylate, and diethylene glycol diacrylate.

[0025] Preferably, the ratio of bisphenol A diglycidyl ether, phosphate ester, isocyanate, hydroxyacrylate, and reactive diluent A is equimolar; the polymerization inhibitor is 0.1-0.5% of the mass of bisphenol A diglycidyl ether; and the catalyst is 0.1-0.5% of the mass of bisphenol A diglycidyl ether.

[0026] Preferably, the polyurethane acrylate is a polyurethane acrylate synthesized from polycarbonate diol, wherein the polycarbonate diol is one of polyethylene carbonate-1,6-hexanediol, polycarbonate-1,5-pentanediol-1,6-hexanediol, and polycarbonate-1,4-butanediol-1,6-hexanediol.

[0027] Preferably, the polyurethane silicone prepolymer containing double bonds is a 2-4 functional group unsaturated polyurethane silicone prepolymer.

[0028] Preferably, the nitrogen-containing acrylic monomer includes one or more of triallyl cyanurate and triallyl isocyanurate.

[0029] Preferably, the phosphorus-based flame retardant A includes one or more of phenoxycyclotriphosphazene and its derivatives, phenoxycyclotetraphosphazene and its derivatives, and phenoxycyclopentaphosphazene and its derivatives.

[0030] Preferably, the phosphorus-based flame retardant B includes one or more of the following: phosphenanthrene triazine compound TAD, 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphatidylphenanthrene.

[0031] Preferably, the reactive diluent B includes one or more of alkyloxyneopentyl glycol diacrylate and cyclohexanediethanol diacrylate.

[0032] Preferably, the other additives include one or more of the following: 1-3 parts initiator, 0.3-0.8 parts anti-aging agent, 2-5 parts UV absorber, and 0.2-0.5 parts light stabilizer.

[0033] Preferably, the initiator includes one or more of 1173, 184, BP, TPO, and 819.

[0034] Preferably, the anti-aging agent includes one or more of hindered phenolic antioxidants 1076, 1098, and 1010.

[0035] Preferably, the UV absorber includes one or more of the triazine UV absorbers UV1164, UV1577, and UV400.

[0036] Preferably, the light stabilizer includes one or more of benzotriazole light stabilizers UV1130 and UV928.

[0037] This invention also provides a method for preparing a transparent phosphorus-containing photocurable flame-retardant coating, comprising the following steps:

[0038] (1) Bisphenol A diglycidyl ether is reacted with phosphate ester at 70~80℃ for 3~5h to obtain a phosphorus-containing intermediate; isocyanate is heated to 50~60℃ and polymerization inhibitor and catalyst are added, then hydroxy acrylate is added and reacted at 40~50℃ until the -NCO value does not change, then the phosphorus-containing intermediate and reactive diluent A are added, the temperature is raised to 70~80℃ and reacted until the -NCO value is <0.5% to obtain phosphorus-containing polyurethane acrylate, which is used as component A;

[0039] (2) Mix polyurethane acrylate, polyurethane silicone prepolymer containing double bonds, nitrogen-containing acrylic monomer, phosphorus flame retardant A and phosphorus flame retardant B in the specified proportions to form component B.

[0040] (3) Mix reactive diluent B and silica sol according to the specified ratio, and then add silane coupling agent as component C;

[0041] (4) Mix the above components A, B and C, add other additives to obtain a coating liquid; irradiate the coating liquid with UV to obtain a transparent phosphorus-containing photocurable flame retardant coating.

[0042] The present invention also provides an application of a transparent phosphorus-containing photocurable flame-retardant coating in lightweight flexible components.

[0043] Beneficial effects

[0044] (1) The coating of the present invention has adhesion, flame retardancy and weather resistance. It can be directly cured on the lightweight flexible photovoltaic module panel and back panel by UV curing to achieve the effects of transparency, fireproofing, flame retardancy and weather resistance.

[0045] (2) The present invention synthesizes phosphorus-containing polyurethane acrylate with both strength and weather resistance, which improves the adhesion stability of the coating while increasing the oxygen index and critical quenching heat flux of the material.

[0046] (3) The present invention adds weather-resistant and flexible polyurethane acrylate, which increases the free volume of the resin matrix and reduces the glass transition temperature of the coating, so that the resin as a whole can still maintain good resistance to damp heat after other components are added to the formula.

[0047] (4) The present invention uses polyurethane silicone prepolymer containing double bonds to improve the hydrolysis resistance of the coating, so that the coating has high resistance to damp heat.

[0048] (5) The present invention selects nitrogen-containing acrylic monomer as gas source and then compounded with phosphazene flame retardant. Without adding halogen flame retardant and charring agent, the coating flame retardant reaches the flame retardant level of UL94 5VB or above.

[0049] (6) The present invention uses silica sol as a carbonization center to maintain the light transmittance of the coating. Without the addition of inorganic fillers, the flame-retardant coating is cured by UV irradiation in one step. Silica sol can also greatly improve the wear resistance of the material. Detailed Implementation

[0050] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0051] The phosphorus-containing polyurethane acrylate components used in the examples are shown in Table 1, and the preparation method includes the following steps:

[0052] Bisphenol A diglycidyl ether was reacted with phosphate ester at 70°C for 3 hours to obtain a phosphorus-containing intermediate. Isocyanate was heated to 50°C and a polymerization inhibitor and catalyst were added. Hydroxy acrylate was then added and reacted at 40°C until the -NCO value did not change. The phosphorus-containing intermediate and reactive diluent A were then added, and the temperature was raised to 70°C. The reaction was continued until the -NCO value was <0.5% to obtain a phosphorus-containing polyurethane acrylate, denoted as P-EUA, which was used as component A.

[0053] Table 1

[0054]

[0055] Table 2 Formulations of transparent phosphorus-containing photocurable flame-retardant coatings (Examples, parts by weight)

[0056]

[0057] Table 3. Formulations of transparent phosphorus-containing photocurable flame-retardant coatings (comparative examples, parts by weight)

[0058]

[0059] The preparation method of the transparent phosphorus-containing photocurable flame-retardant coating includes the following steps:

[0060] (1) Mix polyurethane acrylate, polyurethane silicone prepolymer containing double bonds, nitrogen-containing acrylic monomer, phosphorus flame retardant A and phosphorus flame retardant B in the specified proportions to form component B;

[0061] (2) Mix reactive diluent B and silica sol according to the specified ratio, and then add silane coupling agent as component C;

[0062] (3) Mix the above components A, B and C, add other additives to obtain a coating liquid; use a wire rod to screen print the coating liquid onto the PET surface, surface dry for 1 min, surface dry temperature 50°C, then cover with film and remove air;

[0063] (4) UV irradiation: The UV LED curing lamp has a wavelength of 365nm and a power of 1~5W / cm². 2 The transparent phosphorus-containing photocurable flame-retardant coating is obtained by irradiating the LED for more than 30 seconds and coating for about 15 μm.

[0064] Table 4 Test Results of Transparent Phosphorus-Containing Photocurable Flame Retardant Coatings (Examples)

[0065]

[0066] Table 5 Test results of transparent phosphorus-containing photocurable flame-retardant coatings (comparative examples)

[0067]

[0068] in conclusion:

[0069] 1. Comparing Example 1, Comparative Example 1, and Example 2, phosphorus-containing polyurethane acrylate can significantly improve the oxygen index of the material, increase the critical extinction heat flux of the material, and the coating adhesion is higher than that of pure polyurethane acrylate.

[0070] 2. Comparing Example 2, Comparative Example 2, and Example 3, the polyurethane silicone prepolymer containing double bonds can significantly improve the hydrolysis resistance of the material, greatly reduce the yellow index after humid heat and humid heat UV aging, and also improve the overall hydrolysis resistance of the coating and increase the retention of adhesion.

[0071] 3. Comparing Example 3, Comparative Example 3, and Example 4, without the addition of the gas source monomer triallyl isocyanurate, the adhesion of the material coating increased, but the critical quenching heat flux decreased and NG occurred. However, with the addition of too much gas source monomer, the coating adhesion decreased and the coating weather resistance deteriorated.

[0072] 4. Comparing Example 4, Comparative Example 4, and Example 5, the addition of phosphorus-containing flame retardant can significantly increase the oxygen index and achieve a flame retardancy rating of 5VA, but it will reduce the adhesion and hydrolysis resistance of the material.

[0073] 5. Comparing Example 5, Comparative Example 5, and Example 6, the triazine compound TAD can significantly increase the critical quenching heat flux of the material. The principle is that the gas-source flame retardant forms a cross-linked structure during the carbonization process, thereby increasing the carbonization rate.

[0074] 6. Comparing Example 6, Comparative Example 6, and Example 7, silica sol, acting as a carbon-forming center, can form a Si-N / Si-C ceramic carbon layer with TAD and flame retardants, slowing down flame propagation in the material. Therefore, even with similar oxygen indices, silica sol can significantly increase the critical quenching heat flux of the material. Simultaneously, the nano-carbon layer also increases the wear resistance of the coating.

[0075] 7. Comparison of Examples 7 and 8 shows that increasing the functionality of the initial glycidyl ether epoxy can improve the adhesion of the coating. This is because acid anhydrides are polar groups, which promote the adhesion of acid anhydrides and can also significantly improve the wear resistance of the coating.

[0076] 8. In comparison with Example 8 and Comparative Example 7, if polyurethane acrylate is not added, the overall material's resistance to damp heat is reduced, resulting in a significant decrease in coating adhesion and an increase in the yellow index after damp heat aging.

Claims

1. A transparent phosphorus-containing photocurable flame-retardant coating, characterized in that: By weight, it includes the following components: 20-60 parts of phosphorus-containing polyurethane acrylate; 30-40 parts of polyurethane acrylate; 1-3 parts of polyurethane silicone prepolymer containing double bonds; 3-6 parts of nitrogen-containing acrylic monomer; 5-10 parts of phosphorus-based flame retardant A; 2-4 parts of phosphorus-based flame retardant B; 1-3 parts of silica sol; 3-9 parts of reactive diluent B; and 0.2-0.6 parts of silane coupling agent. Other additives: 3-10 parts; wherein, the phosphorus-containing polyurethane acrylate is prepared from bisphenol A diglycidyl ether, phosphate ester, isocyanate, polymerization inhibitor, catalyst, hydroxy acrylate, and reactive diluent A; the phosphorus-based flame retardant A includes one or more of phenoxycyclotriphosphazene and its derivatives, phenoxycyclotetraphosphazene and its derivatives, and phenoxycyclopentaphosphazene and its derivatives; the phosphorus-based flame retardant B includes one or more of phosphenanthrene triazine compound TAD and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphatidylphenanthrene.

2. The transparent phosphorus-containing photocurable flame-retardant coating according to claim 1, characterized in that: The phosphate ester includes one or more of dibutyl phosphate, trimethylolpropane phosphate, and triphenyl phosphate; the isocyanate includes one or more of toluene diisocyanate, isophorone diisocyanate, and hexacyclohexylmethane diisocyanate; the polymerization inhibitor is hydroquinone; the catalyst includes one or more of dibutyltin dilaurate and stannous octoate; the hydroxy acrylate includes one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, and hydroxybutyl 4-acrylate; and the reactive diluent A includes one or more of tripropylene glycol diacrylate, dipropylene glycol diacrylate, and diethylene glycol diacrylate.

3. The transparent phosphorus-containing photocurable flame-retardant coating according to claim 1, characterized in that: The proportions of bisphenol A diglycidyl ether, phosphate ester, isocyanate, hydroxyacrylate, and reactive diluent A are equimolar; the polymerization inhibitor is 0.1-0.5% of the mass of bisphenol A diglycidyl ether; and the catalyst is 0.1-0.5% of the mass of bisphenol A diglycidyl ether.

4. The transparent phosphorus-containing photocurable flame-retardant coating according to claim 1, characterized in that: The nitrogen-containing acrylic monomer includes one or more of triallyl cyanurate and triallyl isocyanurate.

5. The transparent phosphorus-containing photocurable flame-retardant coating according to claim 1, characterized in that: The active diluent B includes one or more of neopentyl glycol diacrylate and cyclohexanediethanol diacrylate.

6. The transparent phosphorus-containing photocurable flame-retardant coating according to claim 1, characterized in that: The other additives include one or more of the following: 1-3 parts initiator, 0.3-0.8 parts anti-aging agent, 2-5 parts UV absorber, and 0.2-0.5 parts light stabilizer.

7. The transparent phosphorus-containing photocurable flame-retardant coating according to claim 6, characterized in that: The initiator includes one or more of 1173, 184, BP, TPO, and 819; the anti-aging agent includes one or more of hindered phenolic antioxidants 1076, 1098, and 1010; the UV absorber includes one or more of triazine UV absorbers UV1164, UV1577, and UV400; and the light stabilizer includes one or more of benzotriazole light stabilizers UV1130 and UV928.

8. A method for preparing a transparent phosphorus-containing photocurable flame-retardant coating as described in any one of claims 1 to 7, characterized in that, Includes the following steps: (1) Bisphenol A diglycidyl ether is reacted with phosphate ester at 70~80℃ for 3~5h to obtain a phosphorus-containing intermediate; isocyanate is heated to 50~60℃ and polymerization inhibitor and catalyst are added, then hydroxy acrylate is added and reacted at 40~50℃ until the -NCO value does not change, then the phosphorus-containing intermediate and reactive diluent A are added, the temperature is raised to 70~80℃ and reacted until the -NCO value is <0.5% to obtain phosphorus-containing polyurethane acrylate, which is used as component A; (2) Mix polyurethane acrylate, polyurethane silicone prepolymer containing double bonds, nitrogen-containing acrylic monomer, phosphorus flame retardant A and phosphorus flame retardant B in the specified proportions to form component B; (3) Mix reactive diluent B and silica sol according to the specified ratio, and then add silane coupling agent as component C; (4) Mix the above components A, B and C, add other additives to obtain a coating liquid; irradiate the coating liquid with UV to obtain a transparent phosphorus-containing photocurable flame retardant coating.

9. The application of a transparent phosphorus-containing photocurable flame-retardant coating as described in any one of claims 1 to 7 in lightweight flexible components.

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