A heat-resistant, water-resistant and flame-retardant backboard composite material and its preparation method and application

Abstract

The present invention relates to a heat-resistant, water-resistant, and flame-retardant backsheet composite material, as well as its preparation method and application. The composite material comprises a phosphorus-containing epoxy acrylate oligomer, a conventional epoxy resin, a toughened epoxy resin, a phosphorus-containing epoxy resin, a filler, an additive flame retardant, a dicyandiamide curing agent, an accelerator, a nitrogen-containing phenolic resin, a latent curing agent, a UV absorber, and an antioxidant. By synthesizing the phosphorus-containing epoxy acrylate oligomer, the present invention increases the phosphorus content in the material, thereby improving the flame retardant properties of the product, thereby addressing the problem of low flame retardant efficiency caused by directly adding phosphorus-based flame retardants.

Description

Technical Field

[0001] The present invention belongs to the technical field of lightweight flexible photovoltaic modules, and in particular relates to a heat-resistant, water-resistant and flame-retardant backplane composite material, and a preparation method and application thereof. Background Art

[0002] Lightweight flexible photovoltaic modules are widely used in industrial and commercial roofs and buildings with weight restrictions. In order to achieve better performance and higher weight reduction requirements, composite materials are used as packaging materials for lightweight flexible modules.

[0003] Due to the iteration of battery technology, PERC is currently shifting to Topcon. Topcon has higher requirements for the barrier properties of materials because the battery slurry is afraid of water. The backsheet water resistance requirement is <0.01g / m 2 Today, traditional composite materials cannot meet this requirement. A typical backsheet construction involves bonding a layer of aluminum foil between two layers of PET, then applying a weather-resistant coating on both sides. This creates a five-layer structure: coating / PET / Al foil / PTE / coating (CPAPC). However, this structure offers limited rigidity. Another technical approach involves adding aluminum foil to the composite material. However, due to the poor linear thermal expansion coefficient and the composite's poor bonding properties at low temperatures, interfacial stress increases as the temperature drops, leading to cracking of the aluminum foil and delamination of the adhesive layer.

[0004] Patent CN101302327B uses a flame-retardant epoxy resin blended with a phosphate-containing compound and a nitrogen-containing phenolic-based resin to prepare a flame-retardant epoxy resin. The resin has good thermal stability and is suitable for compounding with high-temperature copper foil. The main purpose is to improve the heat resistance and flame retardancy of the material. The material has good heat resistance and a high flame retardancy grade, but poor low-temperature performance.

[0005] Patent CN119241785A synthesizes a resin containing a coupling agent as a polymer protective layer and adhesive layer to protect the inorganic oxide coating, thereby solving the problem of increased water vapor transmittance after moisture and heat aging. However, compared with pure aluminum foil, its water barrier effect is still comparable to that of pure aluminum foil, and its water barrier reliability is limited.

[0006] Patent CN104868003A achieves the purpose of water resistance and high breakdown voltage through PET+metal film through special adhesives and coatings. It has good weather resistance, but the linear thermal expansion coefficients between the resin and the metal do not match, and there may be peeling problems after long-term humidity and heat. Moreover, its flame retardant grade is only VTM level, which cannot withstand large flames such as building products. The flame retardant grade is not very meaningful for components. Summary of the Invention

[0007] The present invention provides a heat-resistant, water-resistant and flame-retardant backboard composite material, as well as a preparation method and application thereof. The composite material synthesizes phosphorus-containing epoxy acrylate polymers to increase the phosphorus content in the material, thereby improving the flame retardant performance of the product, and solving the problem of low flame retardant efficiency caused by directly adding phosphorus-based flame retardants.

[0008] The present invention provides a heat-resistant, water-resistant and flame-retardant backsheet composite material, comprising the following components in parts by mass:

[0009] 40-65 parts of phosphorus-containing epoxy acrylate oligomer;

[0010] 5-10 parts of ordinary epoxy resin;

[0011] 3-5 parts of toughened epoxy resin;

[0012] 5-10 parts of phosphorus-containing epoxy resin;

[0013] 2~5 parts of filler;

[0014] 10~20 parts of additive flame retardant;

[0015] 1-3 parts of dicyandiamide curing agent;

[0016] 1~1.5 parts of accelerator;

[0017] 5-10 parts of nitrogen-containing phenolic resin;

[0018] 0.3~2 parts of latent curing agent;

[0019] 2~5 parts of UV absorber;

[0020] 0.5~1.5 parts of antioxidant;

[0021] The phosphorus-containing epoxy acrylate oligomer is obtained by reacting a phosphorus-containing epoxy acrylate monomer, an epoxy acrylate monomer, hydroxy acrylic acid B, and a reactive diluent under the action of an initiator.

[0022] Preferably, the phosphorus-containing epoxy acrylate monomer is obtained by reacting isocyanate, hydroxy acrylate A, polycarbonate diol, and phosphorus-containing aromatic diol in the presence of a polymerization inhibitor and a catalyst.

[0023] Preferably, the phosphorus-containing aromatic diol is obtained by reacting bisphenol A epoxy resin and dibutyl phosphate.

[0024] More preferably, the dibutyl phosphate also includes its derivatives, such as 3-hydroxybutyl dibutyl phosphate.

[0025] More preferably, the isocyanate is one of TDI, MDI, IPDI, and hydrogenated MDI, preferably TDI with higher activity.

[0026] More preferably, the hydroxy acrylic acid A and the hydroxy acrylic acid B are one of hydroxyethyl acrylate and hydroxypropyl acrylate.

[0027] More preferably, the polycarbonate diol is one of polyhexamethylene carbonate diol, polyhexamethylene carbonate-1,6-diol, polycaprolactone hexamethylene carbonate diol, polybutylene carbonate diol, polyhexamethylene carbonate diol, and polypropylene carbonate diol, with a number average molecular weight Mn of 500-2000 and a hydroxyl value of 40-200 mgKOH / g.

[0028] More preferably, the polymerization inhibitor is hydroquinone.

[0029] More preferably, the catalyst is one of dibutyltin dilaurate and dibutyltin diacetate.

[0030] Preferably, the epoxy acrylate monomer is a bifunctional acrylate containing a double bond and an epoxy group, such as glycidyl acrylate or glycidyl methacrylate.

[0031] Preferably, the reactive diluent is one of 1,6-hexanediol diacrylate (HDDA), diethylene glycol methacrylate (DEGDMA), and triethylene glycol dimethacrylate (TREGDMA).

[0032] Preferably, the initiator is a peroxide or azo initiator, such as dibenzoyl peroxide, di-tert-butyl peroxide, azobisisobutyronitrile, or azodicarbonamide.

[0033] Preferably, the epoxy equivalent of the common epoxy resin is between 180 and 300 g / eq.

[0034] Preferably, the toughened epoxy resin is a high-toughness bisphenol A or bisphenol F epoxy resin with epoxy end groups, with a molecular weight Mw between 51,000 and 59,000 and an epoxy equivalent weight between 7,800 and 8,200.

[0035] Preferably, the phosphorus-containing epoxy resin is a solvent-free phosphorus-based phenol novolac epoxy resin with an epoxy equivalent weight of 300 to 380 g / eq and a glass transition temperature of 65 to 85°C.

[0036] Preferably, the filler is rutile TiO2.

[0037] Preferably, the additive flame retardant is a phenoxy cyclophosphazene flame retardant, including one or more of phenoxy cyclotriphosphazene and its derivatives, phenoxy cyclotetraphosphazene and its derivatives, and phenoxy cyclopentaphosphazene and its derivatives.

[0038] Preferably, the accelerator is an organic urea accelerator, including one or more of N,N-diphenylurea, N,N-dimethylurea, and N,N-di(p-tolyl)urea.

[0039] Preferably, the nitrogen-containing phenolic resin is a melamine-modified phenolic resin.

[0040] Preferably, the latent curing agent is an isocyanate latent curing agent.

[0041] Preferably, the UV absorber is a benzotriazole UV absorber or a benzophenone UV absorber.

[0042] Preferably, the antioxidant is a hindered phenol antioxidant.

[0043] The present invention also provides a method for preparing a heat-resistant, water-resistant and flame-retardant backsheet composite material, comprising the following steps:

[0044] (1) Bisphenol A epoxy resin and dibutyl phosphate are reacted at a molar ratio of 1:1 at 70-90°C for 1-3 hours to obtain a phosphorus-containing aromatic diol;

[0045] (2) reacting isocyanate, hydroxy acrylic acid A, polycarbonate diol, and phosphorus-containing aromatic diol in the presence of a polymerization inhibitor and a catalyst for 1-3 hours to obtain a phosphorus-containing epoxy acrylate monomer;

[0046] (3) reacting a phosphorus-containing epoxy acrylate monomer, an epoxy acrylate monomer, hydroxy acrylic acid B, and a reactive diluent under the action of an initiator for 0.5-1 h to obtain a phosphorus-containing epoxy acrylate oligomer;

[0047] (4) Phosphorus-containing epoxy acrylate copolymer, ordinary epoxy resin, toughened epoxy resin, phosphorus-containing epoxy resin, filler, additive flame retardant, dicyandiamide curing agent, accelerator, nitrogen-containing phenolic resin, latent curing agent, UV absorber, and antioxidant are mixed in proportion to obtain a heat-resistant, water-resistant, and flame-retardant backboard composite material.

[0048] Preferably, the molar ratio of isocyanate, hydroxy acrylic acid A, polycarbonate diol, and phosphorus-containing aromatic diol in step (2) is 1:1:0.5:0.5.

[0049] Preferably, the addition ratio of the polymerization inhibitor in step (2) is 1 / 55 of the molar amount of hydroxy acrylic acid A.

[0050] Preferably, the addition ratio of the catalyst in step (2) is 1 / 150 of the molar amount of the polycarbonate diol.

[0051] Preferably, the molar ratio of the phosphorus-containing epoxy acrylate monomer, epoxy acrylate monomer, hydroxy acrylic acid B, and reactive diluent in step (3) is 1:1:1:1.

[0052] Preferably, the addition ratio of the initiator in step (3) is 1 wt % of the phosphorus-containing epoxy acrylate monomer.

[0053] The present invention also provides an application of a heat-resistant, water-resistant and flame-retardant backboard composite material in a lightweight flexible photovoltaic module.

[0054] Beneficial effects

[0055] (1) The present invention synthesizes phosphorus-containing epoxy acrylate oligomers to increase the phosphorus content in the composite material, thereby improving the flame retardant properties of the product and solving the problem of low flame retardant efficiency caused by directly adding phosphorus-based flame retardants.

[0056] (2) The present invention prepares a phosphorus-containing epoxy acrylate monomer containing polycarbonate diol, which reduces the lower limit of the material's operating temperature, improves the material's flame retardancy while also making it weather-resistant and partially flexible, so that the composite material and the aluminum foil will not delaminate due to high and low temperature impacts, thereby preventing the breakdown voltage from being reduced.

[0057] (3) The phosphorus-containing epoxy acrylate oligomer of the present invention can further cross-link with the main body of the composite material, thereby improving the overall cross-linking degree of the composite resin, enhancing the compatibility of epoxy acrylate and epoxy resin, and thereby increasing the cohesive strength.

[0058] (4) The nitrogen-containing phenolic resin of the present invention improves the heat resistance of the composite material. When combined with the phosphorus-containing epoxy acrylate oligomer and other flame retardants, it has a PN synergistic flame retardant effect, thereby improving the flame retardant effect of the material.

[0059] (5) The toughened epoxy resin of the present invention improves the physical properties of the material and improves the cross-linking degree of the material through thermal curing, thereby solving the problem of increased viscosity caused by excessive high-viscosity resin, high reaction temperature of the curing agent, and low cross-linking degree caused by difficult diffusion of the curing agent. DETAILED DESCRIPTION

[0060] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0061] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0062] The preparation method of the phosphorus-containing epoxy acrylate oligomer in the embodiment comprises the following steps:

[0063] (1) Add 1 mol of bisphenol A epoxy resin (Nan Ya Resin NEPL128) into a three-necked flask, heat it to 70°C, slowly add 1 mol of dibutyl phosphate dropwise over 1 hour, heat it to 90°C and react for 3 hours to obtain a phosphorus-containing aromatic diol, recorded as P-Diol.

[0064] (2) 1 mol of TDI (Bluestar TDI-80) was added to a three-necked flask and heated to 40°C~50°C. 2 g of hydroquinone and 2 g of dibutyltin dilaurate were added. 1 mol of hydroxyethyl acrylate was added to the TDI and reacted until the -NCO value remained unchanged. 0.5 mol of the above-mentioned phosphorus-containing aromatic diol and 0.5 mol of polycarbonate diol (Asahi Kasei T6001) were added and heated to 70°C. The reaction was continued until the -NCO value remained unchanged to obtain a phosphorus-containing epoxy acrylate monomer, which was recorded as SP-Epoxy-AC.

[0065] (3) 60 parts by mass of phosphorus-containing epoxy acrylate monomer, 10 parts by mass of glycidyl methacrylate, 20 parts by mass of tripropylene glycol diacrylate (TPGDA), and 10 parts by mass of hydroxyethyl acrylate, a total of 100 parts by mass of resin, were mixed, N2 was introduced, the temperature was raised to 60°C, and azobisisobutyronitrile and 1,6-hexanediol diacrylate (HDDA) with a mass ratio of 5% of azobisisobutyronitrile were added dropwise within 30 minutes. The amount of azobisisobutyronitrile added was 1 part by mass. After the addition was completed, the reaction was allowed to proceed for half an hour. After the reaction was completed, a phosphorus-containing epoxy acrylate copolymer was formed, which was recorded as P-Epoxy-AC.

[0066] It should be emphasized that the above preparation steps are only examples, and those skilled in the art can make routine substitutions based on common knowledge.

[0067] Table 1 Formula of heat-resistant, water-resistant and flame-retardant backsheet composite material (Example)

[0068]

[0069] Table 2 Heat-resistant, water-resistant and flame-retardant backsheet composite material formula (comparative example)

[0070]

[0071] Table 3 Test results of heat-resistant, water-resistant and flame-retardant backsheet composite materials (Example)

[0072]

[0073] Table 4 Test results of heat-resistant, water-resistant and flame-retardant backsheet composite materials (comparative example)

[0074]

[0075] The present invention uses breakdown voltage to characterize the water-blocking effect. If the water-blocking effect is poor, it is mainly reflected in a decrease in breakdown voltage.

[0076] From the above results, we can see that:

[0077] 1. A comparison between Example 1 and Comparative Example 1 demonstrates that the phosphorus-containing epoxy acrylate oligomer primarily increases the phosphorus content of the resin in the system, significantly reducing the area of ​​damage under high flame conditions. Furthermore, because the epoxy acrylate contains a polycarbonate structure, it exhibits excellent flexibility, maintaining a high breakdown voltage after high and low temperature impacts (-40°C to 85°C).

[0078] 2. Comparison between Example 2, Example 3, and Comparative Example 2 shows that toughened epoxy resin can increase the adhesion between the resin and the aluminum foil, maintaining a higher breakdown voltage.

[0079] 3. Comparison between Example 4, Example 5, and Comparative Example 3 shows that fillers can significantly improve the flame retardancy of materials, because TiO2 can not only become a carbonization center at high temperatures, reducing the continuous burning of flames caused by the wick effect of the fiber, but also act as a Lewis acid to promote carbonization.

[0080] 4. Comparison between Example 5, Example 6, and Comparative Example 4 shows that additive flame retardants can significantly increase the oxygen index of a material, making it more difficult for a flame to burn.

[0081] 5. Comparison between Example 6, Example 7, and Comparative Example 5 shows that nitrogen-containing phenolic acid resin can significantly reduce the damaged area during combustion. This is because the nitrogen-containing phenolic acid resin synergistically retards flame retardancy with the phosphorus-containing resin and flame retardant, generating gas that slows down flame spread.

[0082] 6. Comparison between Example 7, Example 8, and Comparative Example 6 shows that the addition of isocyanate can improve the crosslinking degree of the material, increase the heat resistance of the material, maintain a high glass transition temperature of the material, and alleviate the problem of reduced heat resistance of the material caused by the addition of phosphorus-based flame retardants.

Claims

1. A heat-resistant, water-resistant and flame-retardant backsheet composite material, characterized by: By mass, it includes the following components: The phosphorus-containing epoxy acrylate oligomer is obtained by reacting a phosphorus-containing epoxy acrylate monomer, an epoxy acrylate monomer, hydroxy acrylate B, and an active diluent under the action of an initiator; the phosphorus-containing epoxy acrylate monomer is obtained by reacting an isocyanate, hydroxy acrylate A, a polycarbonate diol, and a phosphorus-containing aromatic diol under the action of an inhibitor and a catalyst; the phosphorus-containing aromatic diol is obtained by reacting a bisphenol A epoxy resin and dibutyl phosphate; and the filler is rutile TiO2.

2. The heat-resistant, water-resistant and flame-retardant backsheet composite material according to claim 1, characterized in that: The toughened epoxy resin is a high-toughness bisphenol A or bisphenol F epoxy resin with epoxy end groups; the phosphorus-containing epoxy resin is a solvent-free phosphorus-based phenol novolac epoxy resin.

3. The heat-resistant, water-resistant and flame-retardant backsheet composite material according to claim 1, characterized in that: The additive flame retardant is a phenoxy cyclophosphazene flame retardant.

4. The heat-resistant, water-resistant and flame-retardant backsheet composite material according to claim 1, characterized in that: The accelerator is an organic urea accelerator; the nitrogen-containing phenolic resin is a melamine-modified phenolic resin; and the latent curing agent is an isocyanate latent curing agent.

5. The heat-resistant, water-resistant and flame-retardant backsheet composite material according to claim 1, characterized in that: The UV absorber is a benzotriazole UV absorber or a benzophenone UV absorber; and the antioxidant is a hindered phenol antioxidant.

6. A method for preparing the heat-resistant, water-resistant and flame-retardant backsheet composite material according to any one of claims 1 to 5, comprising the following steps: (1) reacting bisphenol A epoxy resin and dibutyl phosphate in a molar ratio of 1:1 at 70-90° C. for 1-3 hours to obtain a phosphorus-containing aromatic diol; (2) reacting isocyanate, hydroxy acrylate A, polycarbonate diol, and phosphorus-containing aromatic diol in the presence of a polymerization inhibitor and a catalyst for 1-3 hours to obtain a phosphorus-containing epoxy acrylate monomer; (3) reacting a phosphorus-containing epoxy acrylate monomer, an epoxy acrylate monomer, a hydroxy acrylate B, and a reactive diluent under the action of an initiator for 0.5-1 h to obtain a phosphorus-containing epoxy acrylate oligomer; (4) Phosphorus-containing epoxy acrylate copolymer, ordinary epoxy resin, toughened epoxy resin, phosphorus-containing epoxy resin, filler, additive flame retardant, dicyandiamide curing agent, accelerator, nitrogen-containing phenolic resin, latent curing agent, UV absorber, and antioxidant are mixed in proportion to obtain a heat-resistant, water-resistant, and flame-retardant backboard composite material.

7. Use of the heat-resistant, water-resistant and flame-retardant backsheet composite material according to any one of claims 1 to 5 in a lightweight flexible photovoltaic module.

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