Heat-resistant, water-resistant and flame-retardant backboard composite material as well as preparation method and application thereof

Abstract

The invention relates to a heat-resistant, water-resistant and flame-retardant backboard composite material as well as a preparation method and application thereof. The heat-resistant, water-resistant and flame-retardant backboard composite material comprises a phosphorus-containing epoxy acrylate oligomer, common epoxy resin, toughened epoxy resin, phosphorus-containing epoxy resin, a filler, an additive flame retardant, a dicyandiamide curing agent, an accelerant, nitrogen-containing phenolic resin, a latent curing agent, a UV absorbent and an antioxidant. The phosphorus content in the material is improved by synthesizing the phosphorus-containing epoxy acrylate oligomer, so that the flame retardant property of the product is improved, and the problem of low flame retardant efficiency caused by direct addition of a phosphorus flame retardant is solved.

Description

Technical Field

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

[0002] Lightweight flexible photovoltaic modules are widely used in industrial and commercial rooftops and construction fields with weight-bearing restrictions. In order to achieve better performance and higher weight reduction requirements, composite materials are used as encapsulation materials for lightweight flexible modules.

[0003] Due to the iteration of battery technology, currently there is a transition from PERC to Topcon. Since the battery slurry of Topcon is afraid of water, higher requirements are put forward for the barrier performance of materials. The water-blocking requirement for the backsheet is <0.01g / m 2 *day, and traditional composite materials cannot meet this requirement. Usually, the backsheet is made by sticking an aluminum foil between two layers of PET and then brushing weather-resistant coatings on both sides to form a five-layer structure of coating / PET / Al foil / PTE / coating (CPAPC). However, the rigidity of this structure is relatively low. Another technical route is to add aluminum foil to the composite material. However, due to the poor linear thermal expansion coefficient and the poor bonding performance of the composite material at low temperatures, as the temperature decreases, the interfacial stress becomes too large, resulting in problems such as aluminum foil cracking and bonding layer peeling.

[0004] In the patent CN101302327B, phenolic epoxy resin is blended with a phosphate compound and a nitrogen-containing phenolic resin to prepare a flame-retardant epoxy resin. It has good thermal stability and is suitable for compounding with high-temperature copper foil. Its 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 rating, but its low-temperature performance is poor.

[0005] In the patent CN119241785A, a resin containing a coupling agent is synthesized as a polymer protective layer and a bonding layer to protect the inorganic oxide coating layer and solve the problem of increased water vapor transmittance after resistance to damp heat aging. However, compared with pure aluminum foil, there is still water vapor permeation in its own water-blocking effect, and the improvement of its water-blocking reliability is limited.

[0006] In the patent CN104868003A, PET + metal film is used to achieve the purpose of water blocking and high breakdown voltage through special adhesives and coatings. It has good weather resistance. However, the linear thermal expansion coefficients between the resin and the metal do not match, and peeling problems may occur after long-term wet heat. Moreover, its flame retardancy rating is only VTM level and it cannot withstand large flame combustion of building products. The flame retardancy rating has little significance for the module. Summary of the Invention

[0007] The present invention provides a heat-resistant, water-resistant and flame-retardant backplane composite material, its preparation method and application. By synthesizing a phosphorus-containing epoxy acrylate oligomer, the phosphorus content in the material is increased, thereby improving the flame-retardant performance of the product and solving the problem of low flame-retardant efficiency caused by directly adding a phosphorus-based flame retardant.

[0008] The present invention provides a heat-resistant, water-resistant and flame-retardant backplane composite material, which comprises the following components by mass parts: 40 - 65 parts of phosphorus-containing epoxy acrylate oligomer; 5 - 10 parts of ordinary epoxy resin; 3 - 5 parts of toughened epoxy resin; 5 - 10 parts of phosphorus-containing epoxy resin; 2 - 5 parts of filler; 10 - 20 parts of additive flame retardant; 1 - 3 parts of dicyandiamide curing agent; 1 - 1.5 parts of accelerator; 5 - 10 parts of nitrogen-containing phenolic resin; 0.3 - 2 parts of latent curing agent; 2 - 5 parts of UV absorber; 0.5 - 1.5 parts of antioxidant; Among them, 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 an active diluent under the action of an initiator.

[0009] Preferably, the phosphorus-containing epoxy acrylate monomer is obtained by reacting an isocyanate, hydroxy acrylic acid A, a polycarbonate diol, and a phosphorus-containing aromatic diol under the action of an inhibitor and a catalyst.

[0010] Preferably, the phosphorus-containing aromatic diol is obtained by reacting bisphenol A epoxy resin and dibutyl phosphate.

[0011] More preferably, the dibutyl phosphate further includes its derivatives, such as 3-hydroxybutyl dibutyl phosphate.

[0012] More preferably, the isocyanate is one of TDI, MDI, IPDI, and hydrogenated MDI, and preferably TDI with higher activity.

[0013] More preferably, the hydroxy acrylic acid A and hydroxy acrylic acid B are one of hydroxyethyl acrylate and hydroxypropyl acrylate.

[0014] More preferably, the polycarbonate diol is one of polyhexamethylene carbonate diol, poly-1,6-hexanediol carbonate, polycaprolactone hexamethylene carbonate diol, polybutylene carbonate diol, polyhexylene carbonate diol, and polypropylene carbonate diol, with a number average molecular weight Mn = 500 to 2000 and a hydroxyl value between 40 and 200 mgKOH / g.

[0015] More preferably, the inhibitor is hydroquinone.

[0016] More preferably, the catalyst is one of dibutyltin dilaurate and dibutyltin diacetate.

[0017] Preferably, the epoxy acrylate monomer is a bifunctional acrylate containing a double bond and an epoxy group, such as one of glycidyl acrylate and glycidyl methacrylate.

[0018] Preferably, the active diluent is one of 1,6 - hexanediol diacrylate (HDDA), diethylene glycol methacrylate (DEGDMA), and triethylene glycol dimethacrylate (TREGDMA).

[0019] Preferably, the initiator is a peroxide or azo initiator, such as one of benzoyl peroxide, di-tert-butyl peroxide, azobisisobutyronitrile, and azodicarbonamide.

[0020] Preferably, the epoxy equivalent of the ordinary epoxy resin is between 180 and 300 g / eq.

[0021] 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 51000 and 59000 and an epoxy equivalent between 7800 and 8200.

[0022] Preferably, the phosphorus-containing epoxy resin is a solvent-free phosphorus-based phenol novolac epoxy resin, with an epoxy equivalent between 300 and 380 g / eq and a glass transition temperature between 65 and 85 °C.

[0023] Preferably, the filler is rutile TiO2.

[0024] Preferably, the additive flame retardant is a phenoxycyclophosphazene-based flame retardant, including one or more of phenoxycyclotriphosphazene and its derivatives, phenoxycyclotetraphosphazene and its derivatives, and phenoxycyclopentaphosphazene and its derivatives.

[0025] 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.

[0026] Preferably, the nitrogen-containing phenolic resin is a melamine-modified phenolic resin.

[0027] Preferably, the latent curing agent is an isocyanate latent curing agent.

[0028] Preferably, the UV absorber is a benzotriazole UV absorber or a benzophenone UV absorber.

[0029] Preferably, the antioxidant is a hindered phenol antioxidant.

[0030] The present invention also provides a method for preparing a heat-resistant, water-resistant and flame-retardant backplane composite material, comprising the following steps: (1) React bisphenol A epoxy resin and dibutyl phosphate at a molar ratio of 1:1 at 70-90 °C for 1-3 h to obtain a phosphorus-containing aromatic diol; (2) React an isocyanate, hydroxy acrylic acid A, polycarbonate diol, and phosphorus-containing aromatic diol in the presence of an inhibitor and a catalyst for 1-3 h to obtain a phosphorus-containing epoxy acrylate monomer; (3) React the phosphorus-containing epoxy acrylate monomer, epoxy acrylate monomer, hydroxy acrylic acid B, and reactive diluent in the presence of an initiator for 0.5-1 h to obtain a phosphorus-containing epoxy acrylate oligomer; (4) Mix the phosphorus-containing epoxy acrylate oligomer, 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 in proportion to obtain a heat-resistant, water-resistant and flame-retardant backplane composite material.

[0031] Preferably, the molar ratio of the isocyanate, hydroxy acrylic acid A, polycarbonate diol, and phosphorus-containing aromatic diol in step (2) is 1:1:0.5:0.5.

[0032] Preferably, the addition ratio of the inhibitor in step (2) is 1 / 55 of the molar amount of hydroxy acrylic acid A.

[0033] Preferably, the addition ratio of the catalyst in step (2) is 1 / 150 of the molar amount of polycarbonate diol.

[0034] 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.

[0035] Preferably, the addition ratio of the initiator in step (3) is 1 wt% of the phosphorus-containing epoxy acrylate monomer.

[0036] The present invention also provides an application of the heat-resistant, water-resistant and flame-retardant backplane composite material in a lightweight flexible photovoltaic module.

[0037] Beneficial effects

[0038] (1) By synthesizing a phosphorus-containing epoxy acrylate oligomer, the present invention increases the phosphorus content in the composite material, thereby improving the flame retardancy of the product and solving the problem of low flame retardant efficiency caused by directly adding a phosphorus-based flame retardant.

[0039] (2) The present invention prepares a phosphorus-containing epoxy acrylate monomer containing polycarbonate diol, which lowers the lower limit of the use temperature of the material, has weather resistance and partial flexibility while improving the flame retardancy of the material, and prevents the composite material from detaching from the aluminum foil due to high and low temperature impacts, thereby avoiding the problem of reduced breakdown voltage.

[0040] (3) The phosphorus-containing epoxy acrylate oligomer of the present invention can be further crosslinked with the main body of the composite material, improving the overall crosslinking degree of the composite material resin, enhancing the compatibility between the epoxy acrylate and the epoxy resin, and thus increasing the cohesive strength.

[0041] (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 P-N synergistic flame retardant effect, enhancing the flame retardant effect of the material.

[0042] (5) The toughened epoxy resin of the present invention improves the physical properties of the material, and at the same time enhances the crosslinking degree of the material through thermal curing, solving the problems of increased viscosity caused by excessive high-viscosity resin, high reaction temperature of the curing agent, and difficult diffusion of the curing agent resulting in too low crosslinking degree. Specific embodiments

[0043] The following will further illustrate the present invention in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it 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 also fall within the scope defined by the appended claims of this application.

[0044] The reagents, methods, and equipment used in the present invention, unless otherwise specified, are all conventional reagents, methods, and equipment in this technical field.

[0045] The preparation method of the phosphorus-containing epoxy acrylate oligomer in the embodiment includes the following steps: (1) Add 1 mol of bisphenol A epoxy resin (Nanya resin NEPL128) to a three-necked flask, heat up to 70 °C, slowly drop 1 mol of dibutyl phosphate within 1 h, and heat up to 90 °C for reaction for 3 h to obtain a phosphorus-containing aromatic diol, denoted as P-Diol; (2) Add 1 mol of TDI (BlueStar TDI-80) into a three-necked flask, heat it to 40 °C to 50 °C, add 2 g of hydroquinone and 2 g of dibutyltin dilaurate, then add 1 mol of hydroxyethyl acrylate into the TDI. React until the -NCO value remains unchanged. Then add 0.5 mol of the above phosphorus-containing aromatic diol and 0.5 mol of polycarbonate diol (Asahi Kasei T6001), heat it to 70 °C, and react until the -NCO value remains unchanged to obtain a phosphorus-containing epoxy acrylate monomer, denoted as S-P-Epoxy-AC; (3) Blend 60 parts by mass of the 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 the resin. Introduce N2, raise the temperature to 60 °C, and dropwise add azobisisobutyronitrile and 1,6 - hexanediol diacrylate (HDDA) with a mass of 5% of the azobisisobutyronitrile within 30 min. The addition amount of azobisisobutyronitrile is 1 part by mass. After the dropping is completed, react for half an hour, and finally obtain a phosphorus-containing epoxy acrylate oligomer, denoted as P-Epoxy-AC.

[0046] It should be emphasized that the above preparation steps are only examples, and those skilled in the art can make conventional substitutions according to common knowledge.

[0047] Table 1 Formulation of Heat-resistant, Water-resistant and Flame-retardant Backplane Composite Material (Examples)

[0048] Table 2 Formulation of Heat-resistant, Water-resistant and Flame-retardant Backplane Composite Material (Comparative Examples)

[0049] Table 3 Test Results of Heat-resistant, Water-resistant and Flame-retardant Backplane Composite Material (Examples)

[0050] Table 4 Test Results of Heat-resistant, Water-resistant and Flame-retardant Backplane Composite Material (Comparative Examples)

[0051] The present invention characterizes the water resistance effect by the breakdown voltage. If the water resistance effect is not good, it is mainly reflected in the decrease of the breakdown voltage.

[0052] From the above results, it can be seen that: 1. Through the comparison of Example 1 and Comparative Example 1, it shows that the phosphorus-containing epoxy acrylate oligomer mainly increases the phosphorus content of the resin in the system, can significantly reduce the damage area under a large flame, and because the epoxy acrylate contains a polycarbonate structure, it has good flexibility, so that the breakdown voltage remains high after high and low temperature impacts (-40 °C to 85 °C).

[0053] 2. It is illustrated by comparing Example 2, Example 3 and Comparative Example 2 that toughened epoxy resin can increase the adhesion between the resin and the aluminum foil and maintain a relatively high breakdown voltage.

[0054] 3. It is illustrated by comparing Example 4, Example 5 and Comparative Example 3 that the filler can significantly improve the flame retardancy of the material. Because at high temperatures, TiO2 can not only become the center of carbon formation, reducing the continuous combustion of the flame caused by the wick effect of the fiber, but also act as a Lewis acid to promote carbon formation.

[0055] 4. It is illustrated by comparing Example 5, Example 6 and Comparative Example 4 that the addition-type flame retardant can significantly improve the oxygen index of the material, making it more difficult for the flame to burn.

[0056] 5. It is illustrated by comparing Example 6, Example 7 and Comparative Example 5 that the nitrogen-containing phenolic acid resin can significantly reduce the damage area during combustion. This is because the nitrogen-containing phenolic resin and the phosphorus-containing resin and flame retardant have a synergistic flame retardancy effect, generating gas and slowing down the flame spread.

[0057] 6. It is illustrated by comparing Example 7, Example 8 and Comparative Example 6 that the addition of isocyanate can increase the crosslinking degree of the material and improve the heat resistance of the material, enabling the material to maintain a high glass transition temperature and alleviating the problem of reduced heat resistance of the material caused by the addition of the phosphorus-based flame retardant.

Claims

1. A heat-resistant, water-resistant and flame-retardant backsheet composite material, characterized in that: By mass, it includes the following components: 40-65 parts of phosphorus-containing epoxy acrylate oligomer; 5~10 parts of ordinary epoxy resin; 3-5 parts of toughened epoxy resin; 5-10 parts of phosphorus-containing epoxy resin; 2~5 parts of filler; Additive flame retardant 10~20 parts; 1~3 parts of dicyandiamide curing agent; 1~1.5 parts of accelerator; 5-10 parts of nitrogen-containing phenolic resin; 0.3~2 parts of latent curing agent; 2~5 parts of UV absorber; 0.5~1.5 parts of antioxidant; The phosphorus-containing epoxy acrylate oligomer is obtained by reacting phosphorus-containing epoxy acrylate monomer, epoxy acrylate monomer, hydroxy acrylic acid B and active diluent under the action of an initiator.

2. The heat-resistant, water-resistant and flame-retardant backsheet composite material according to claim 1, characterized in that: The phosphorus-containing epoxy acrylate monomer is obtained by reacting isocyanate, hydroxyl acrylic acid A, polycarbonate diol and phosphorus-containing aromatic diol under the action of a polymerization inhibitor and a catalyst.

3. The heat-resistant, water-resistant and flame-retardant backsheet composite material according to claim 2, characterized in that: The phosphorus-containing aromatic diol is obtained by reacting bisphenol A epoxy resin and dibutyl phosphate.

4. 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 terminal groups; the phosphorus-containing epoxy resin is a solvent-free phosphorus-based phenol novolac epoxy resin.

5. The heat-resistant, water-resistant and flame-retardant backsheet composite material according to claim 1, characterized in that: The filler is rutile TiO2.

6. 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.

7. 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.

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

9. A method for preparing the heat-resistant, water-resistant and flame-retardant backsheet composite material according to any one of claims 1 to 8, comprising the following steps: (1) reacting bisphenol A epoxy resin and dibutyl phosphate at 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 acrylic acid A, polycarbonate diol, and phosphorus-containing aromatic diol in the presence of an 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, 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; (4) Phosphorus-containing epoxy acrylate polymer, 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, flame-retardant backplane composite material.

10. Use of the heat-resistant, water-resistant and flame-retardant backplane composite material according to any one of claims 1 to 8 in a lightweight flexible photovoltaic module.

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