Halogen-free flame-retardant transparent composite glass cloth and application thereof

Abstract

The invention belongs to the technical field of light solar cell modules, and particularly relates to halogen-free flame-retardant transparent composite glass cloth and application thereof. The flame-retardant glass cloth comprises glass cloth and an adhesive coated on the surface of the glass cloth, the adhesive comprises acrylic resin, low-molecular-weight polyacrylic acid, low-temperature curing polyester resin, a curing agent, a phosphorus-containing acrylic resin flame retardant and a silane coupling agent, and the phosphorus-containing acrylic resin flame retardant is a product obtained by bonding DOPO into the acrylic resin through chemical reaction. The phosphorus-containing acrylic resin flame retardant provided by the invention has good compatibility with a matrix, in addition, the phosphorus-containing acrylic resin flame retardant can be uniformly dispersed in the matrix through a proper grinding process, the transparency is high after compounding, the efficiency of a solar cell is not influenced, and the silane coupling agent ensures the binding force of an adhesive and glass fiber cloth, so that the flame-retardant performance of the solar cell is improved. And an ultraviolet absorbent prevents the problem of aging and yellowing caused by long-term illumination.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of light solar cell modules, and particularly relates to a halogen-free flame-retardant transparent composite glass cloth and application thereof. BACKGROUND

[0002] With the maturation of solar energy utilization and the technology combined with buildings, the use scenarios of solar cell modules are becoming more and more diversified. For example, solar cell modules can be integrated into applications such as factory roofs, school roofs, and housing roofs.

[0003] Since solar cells need to be assembled on the roof, the requirements for lightness, impact resistance, and flame retardancy are higher compared to traditional solar modules. Patent CN119744008A provides a high-transparency composite glass cloth and a light solar cell module for lightness and impact resistance, and patent CN119704706A provides another epoxy resin composite glass cloth for solar cells.

[0004] Since the front plate in the solar module is the outermost layer on the front, it is directly exposed to sunlight in outdoor environments, so it needs to have transmittance to provide light energy to the cell as much as possible. Therefore, the composite glass cloth of patent CN119744008A is more suitable for front plate reinforcement. The disclosed composite glass cloth mainly includes a glass cloth and an adhesive coated on the surface of the glass cloth, and the adhesive includes an acrylic resin, a low molecular weight polyacrylic acid, a low-temperature curing polyester resin, and a curing agent.

[0005] In order to solve the problem of flame retardancy, the adhesive needs to have high-efficiency flame retardancy. The improvement of flame retardancy can generally be achieved by reacting the flame retardant with the high molecular material through chemical reaction to bond the flame-retardant group into the material. For example, patent CN105237674A provides a preparation method of a phosphorus-containing flame-retardant acrylic resin. However, compared with the traditional method of physically mixing the flame retardant with the high molecular material and then processing the high molecular composite material with flame-retardant function, this method has poor operability. However, the current halogen-free flame retardant has poor dispersibility and fusion after being physically mixed with the above-mentioned adhesive, thereby affecting the play of its flame retardant performance. SUMMARY

[0006] The present application provides a halogen-free flame-retardant transparent composite glass cloth and application thereof to solve the above technical problems.

[0007] To solve the above-mentioned technical problems, the present invention provides a halogen-free flame-retardant transparent composite glass cloth, which includes a glass cloth and an adhesive coated on the surface of the glass cloth. The adhesive includes acrylic resin, low molecular weight polyacrylic acid, low-temperature curing polyester resin, curing agent, phosphorus-containing acrylic resin flame retardant and silane coupling agent. The phosphorus-containing acrylic resin flame retardant is a product in which DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) is chemically bonded to the acrylic resin.

[0008] Phosphorus-containing acrylic resin flame retardants have the advantage of being structurally similar to acrylic resins and are more compatible with other organophosphorus structures.

[0009] Optionally, the phosphorus content of the phosphorus-containing acrylic resin flame retardant is 5-30%.

[0010] Optionally, the preparation method of the phosphorus-containing acrylic resin flame retardant is as follows: a solvent is added to a reaction vessel, and under nitrogen protection, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), butyl acrylate (BA), acrylonitrile (AN), amine acrylate, glycidyl methacrylate (GMA), and azobisisobutyronitrile (AIBN) are added sequentially. The raw material mixture is then heated to 70-80°C, stirred and reacted for 8-10 hours, and cured and molded at 80-130°C.

[0011] Optionally, the preparation method of the adhesive includes the following steps: weighing each component according to the formula and adding it into a solvent, and mixing it using one or more of the following grinding methods: vibratory milling, ball milling and sand milling, until the mixing requirements are met.

[0012] Because phosphorus-containing acrylic resin flame retardants contain large DOPO groups, the chain segments are severely curled. Deep grinding is required to straighten and break down the long chains of the flame retardant so that it can be better dispersed in the matrix and the crystallization zone can be small and uniform to ensure the transparency of the product.

[0013] Optionally, the grinding medium is 0.1mm-1mm zirconium beads, and the grinding temperature is 50-60℃.

[0014] Optionally, the mixing requirement refers to scraping the mixture onto the surface of a metal sheet until the surface is smooth and free of granular crystals.

[0015] Optionally, the silane coupling agent is selected from one or more of γ-aminopropyltriethoxysilane (KH-550), γ-glycidoxypropyltrimethoxysilane (KH-560), and γ-methacryloyloxypropyltrimethoxysilane (KH-570).

[0016] Optionally, the solvent is selected from ethanol or ethyl acetate.

[0017] Optionally, the composition of each component of the adhesive is as follows:

[0018] 100-120 parts acrylic resin

[0019] 100-120 parts of low molecular weight polyacrylic acid

[0020] 50-60 parts of low-temperature curing polyester resin

[0021] Hardener 1.8-2.5 parts

[0022] 10-65 parts of phosphorus-containing acrylic resin flame retardant

[0023] 1-2 parts of silane coupling agent.

[0024] Optionally, the proportion of phosphorus-containing acrylic resin flame retardant in the adhesive is preferably 20-30 parts.

[0025] Optionally, the adhesive may also contain an ultraviolet absorber.

[0026] The added flame retardant affected the product's UV resistance and yellowing resistance. Adding a suitable UV absorber ensured the product's weather resistance and yellowing resistance.

[0027] Optionally, the ultraviolet absorber is selected from UV-326 (2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole).

[0028] Optionally, the viscosity of the adhesive is 1000-5000 Cp.

[0029] Optionally, the preparation method of the composite glass cloth includes the following steps: the adhesive is compounded with the glass cloth roll by spraying, brushing or impregnation, dried at 100-120℃, and finally cut into sheets according to the size requirements of the lightweight solar cell module for later use.

[0030] The present invention also provides a lightweight solar cell module, which includes a polymer front panel, an encapsulating film, the aforementioned halogen-free flame-retardant transparent composite glass cloth, a solar cell, an encapsulating film, and a polymer back panel.

[0031] The phosphorus-containing acrylic resin flame retardant provided by this invention has good compatibility with the matrix. In addition, through a suitable grinding process, it can be evenly dispersed in the matrix, resulting in high transparency after lamination without affecting the efficiency of solar cells. The silane coupling agent ensures the bonding force between the adhesive and the glass fiber cloth, and the ultraviolet absorber prevents the problem of aging and yellowing caused by long-term light exposure. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0033] Example 1 Synthesis of acrylic resin

[0034] The preparation method is as follows: by weight, 15 parts of styrene, 30 parts of methyl methacrylate, 15 parts of n-butyl methacrylate, 40 parts of glycidyl methacrylate monomer and 2 parts of BPO are mixed evenly. When the toluene solution is heated to about 120°C, the above mixture is added dropwise at a uniform rate. After the polymerization reaction is completed and cooled to room temperature, the toluene is removed by vacuum distillation to obtain acrylic resin with a softening point temperature of 90-100°C.

[0035] Example 2 Synthesis of Low-Temperature Curing Polyester Resin

[0036] By weight, add 42 parts neopentyl glycol, 8 parts trimethylolpropane, 50 parts terephthalic acid, and 0.1 parts monobutyltin oxide catalyst to a reactor. Slowly heat the mixture to 235-245°C under nitrogen protection and maintain the temperature until the acid value is 5-10 mg KOH / g. Then, cool the mixture to 210°C, add adipic acid and isophthalic acid, and heat the mixture at 10°C / h to about 240°C. Maintain the temperature until the acid value is 60-65 mg KOH / g, then perform vacuum decompression for 2 hours. Cool the mixture to 205-210°C, add an antioxidant, and maintain the temperature for 20 minutes before discharging.

[0037] Example 3 Preparation of phosphorus-containing acrylic resin flame retardant

[0038] Solvent was added to the reactor, and under nitrogen protection, 9 parts of DOPO, 100 parts of butyl acrylate, 45 parts of acrylonitrile, 5 parts of acrylate amine, 4 parts of GMA and 0.5 parts of AIBN were added sequentially as raw materials according to the proportions of the material composition formula. The raw material mixture was then heated to 80°C and stirred for 9 hours to obtain an acrylic thermoplastic resin solution. The solution was then cured at 120°C, with a phosphorus content of 21.1%.

[0039] Examples 4-6: Halogen-free flame-retardant transparent composite glass cloth

[0040] The acrylic resin prepared in Example 1, the low molecular weight polyacrylate, the low-temperature curing polyester resin prepared in Example 2, the curing agent TGIC (triglycidyl isocyanurate), the phosphorus-containing acrylic resin flame retardant prepared in Example 3, the silane coupling agent KH-550, and the ultraviolet absorber UV-326 were weighed according to the formula in Table 1 and added to ethyl acetate. The mixture was then ground in a high-speed sand mill with 0.6 mm zirconium beads as the grinding media, at a grinding temperature of 50-60°C, and at a grinding ball speed of 1800 rpm, until the mixture was scraped onto the surface of a copper sheet and the surface was smooth and free of granular crystals. The final adhesive viscosity was approximately 2000-2500 Cp.

[0041] Table 1

[0042]

[0043] The adhesive is placed in an impregnation tank and stirred at 1200 rpm. A traction roller pulls the glass cloth through the impregnation tank, and then it is pressed and heated by two heating rollers at a temperature of 100-110°C. The adhesive partially cures on the surface of the glass cloth. The cloth is then wound up to obtain a halogen-free, flame-retardant, transparent composite glass cloth. It is then cut into sheets according to the size requirements of lightweight solar cell modules for later use.

[0044] Example 7: Fabrication of a lightweight solar cell module

[0045] The polymer front plate, encapsulating film, halogen-free flame-retardant transparent composite glass cloth prepared in Example 4, battery cell, encapsulating film and polymer back plate are stacked in sequence and pressed together in a vacuum environment by a press at a temperature of 130-150℃ for 30-40 minutes.

[0046] The material of the polymer front plate is ETFE (ethylene-tetrafluoroethylene copolymer).

[0047] The encapsulating film is EVA.

[0048] The polymer backing material is TPT (polyvinyl fluoride composite film).

[0049] Comparative Example 1

[0050] The difference from Example 4 is that the flame retardant is not the phosphorus-containing acrylic resin flame retardant prepared in Example 3, but is replaced by diethyl aluminum hypophosphite and melamine polyphosphate, wherein the mass ratio of diethyl aluminum hypophosphite and melamine polyphosphate is 5:1.

[0051] Comparative Example 2

[0052] The difference from Example 4 is that the adhesive components were mixed by mechanical stirring for 3 hours at a speed of 800 rpm. After mixing, the mixture was scraped onto the surface of a metal sheet, and granular crystals were present on the surface. The stirring time was extended to 5 hours, and granular crystals were still present on the scraped surface.

[0053] Comparative Example 3

[0054] The difference from Example 4 is that the adhesive does not contain flame retardants, silane coupling agents, or ultraviolet absorbers.

[0055] Performance Experiment

[0056] To verify that the prepared composite glass cloth meets the requirements of solar cell modules, weather resistance, flame retardancy and light transmittance tests were conducted on the composite glass cloths of Examples 4-6 and Comparative Examples 1-3. The test results are shown in Table 2.

[0057] Table 2

[0058]

[0059] As can be seen from Comparative Example 1, Example 4 and Comparative Example 4, although diethylaluminum hypophosphite and melamine polyphosphate can improve flame retardant performance as flame retardants, their poor dispersibility and compatibility in acrylic resin affect the flame retardant performance of the composite glass cloth, and also affect its yellowing resistance. Even with the addition of ultraviolet absorbers, the requirements still cannot be met.

[0060] In Comparative Example 2, since the process involved only mechanical stirring and not grinding, the phosphorus-containing acrylic resin flame retardant chain segments were severely curled, making it difficult to be well compatible and dispersed with the acrylic resin. This resulted in severe crystallization and a sharp drop in the light transmittance of the composite glass cloth.

[0061] Comparative Example 3, which contains no flame retardant, silane coupling agent, or UV absorber in its adhesive, shows that the composite glass cloth has the worst flame retardant effect. In addition, compared with Example 4, it can be found that the addition of phosphorus-containing acrylic resin flame retardant, silane coupling agent, and UV absorber does affect the light transmittance of the composite glass cloth, but our process design allows it to meet the usage requirements of more than 85%.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A halogen-free flame-retardant transparent composite glass cloth, characterized in that, The invention includes glass cloth and an adhesive coated on the surface of the glass cloth. The adhesive includes acrylic resin, low molecular weight polyacrylic acid, low-temperature curing polyester resin, curing agent, phosphorus-containing acrylic resin flame retardant and silane coupling agent. The phosphorus-containing acrylic resin flame retardant is a product in which DOPO is chemically bonded to the acrylic resin.

2. The halogen-free flame-retardant transparent composite glass cloth according to claim 1, characterized in that, The phosphorus content of the phosphorus-containing acrylic resin flame retardant is 5-30%.

3. The halogen-free flame-retardant transparent composite glass cloth according to claim 1, characterized in that, The preparation method of the phosphorus-containing acrylic resin flame retardant is as follows: a solvent is added to a reaction vessel, and under nitrogen protection, DOPO, butyl acrylate, acrylonitrile, amine acrylate, GMA and AIBN are added in sequence. The raw material mixture is then heated to 70-80°C, stirred and reacted for 8-10 hours, and cured and molded at 80-130°C.

4. The halogen-free flame-retardant transparent composite glass cloth according to claim 1, characterized in that, The preparation method of the adhesive includes the following steps: weigh each component according to the formula and put it into the solvent, and mix it by one or more of the following grinding methods: vibration milling, ball milling and sand milling, until the mixing requirements are met.

5. The halogen-free flame-retardant transparent composite glass cloth according to claim 4, characterized in that, The grinding media are 0.1mm-1mm zirconium beads, and the grinding temperature is 50-60℃.

6. The halogen-free flame-retardant transparent composite glass cloth according to claim 4, characterized in that, The mixing requirement refers to scraping the mixture onto the surface of a metal sheet until the surface is smooth and free of granular crystals.

7. The halogen-free flame-retardant transparent composite glass cloth according to claim 4, characterized in that, The silane coupling agent is selected from one or more of KH-550, KH-560 and KH-570.

8. The halogen-free flame-retardant transparent composite glass cloth according to claim 1, characterized in that, The adhesive also contains an ultraviolet absorber.

9. The halogen-free flame-retardant transparent composite glass cloth according to claim 1, characterized in that, The viscosity of the adhesive is 1000-5000 Cp.

10. A lightweight solar cell module, characterized in that... It includes a polymer front panel, an encapsulating film, a halogen-free flame-retardant transparent composite glass cloth as described in any one of claims 1-9, a battery cell, an encapsulating film, and a polymer back panel.

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