A lightweight flame-retardant photovoltaic backsheet and preparation method thereof

Abstract

The present invention relates to a lightweight flame-retardant photovoltaic backboard and a preparation method thereof, wherein the core layer is a modified flame-retardant foamed polystyrene board, the upper surface layer is a thermosetting or thermoplastic composite material with heat-conducting and fire-proof properties, the lower surface layer is a thermosetting or thermoplastic composite material, and the upper and lower surface layers and the core layer are bonded with an adhesive. The photovoltaic backboard of the present invention can achieve Class B fire protection for buildings; compared with fireproof aluminum plates, etc., it has the characteristics of good insulation, and the partial discharge voltage is as high as 2000V; it also has the characteristics of high strength, stable flame retardancy, and has good market application prospects.

Description

Technical Field

[0001] The invention belongs to the field of photovoltaic components, and in particular relates to a lightweight flame-retardant photovoltaic backboard and a preparation method thereof. Background Art

[0002] The photovoltaic backsheet is an important part of the photovoltaic module. It is located on the back of the photovoltaic module and plays a role in protecting and supporting the photovoltaic module. However, most traditional photovoltaic backsheets are made of polymer materials. Although they have good electrical insulation and mechanical strength, these materials are easy to burn in high temperature environments such as fires, causing damage to photovoltaic modules and even fires, posing a threat to personal and property safety.

[0003] In addition, with the rapid development of the photovoltaic industry, the installation and use environments of photovoltaic modules are becoming more and more diverse, such as roofs, carports, farmhouses, etc. The fire risk in these environments is relatively high, so the flame retardant performance requirements of photovoltaic backsheets are also getting higher and higher. However, the existing flame retardant photovoltaic backsheet technology has problems in strength, fire prevention effect, cost, production cycle, etc.

[0004] CN110978674A uses thermoplastic plates and flame retardant layers with hollow grid structures for hot pressing and compounding. The thermoplastic polymer is heated so that it penetrates the flame retardant layer and is pressed together. The patent believes that the flame retardant hollow grid can control the burning flame within the flame retardant hollow grid area, thereby reducing the flame spread index of the photovoltaic flame retardant composite board. When this solution is actually applied, the surface thermoplastic polymer will also cause the flame to spread, and the fibers of the hollow grid will have a wick effect, which will cause continuous combustion. The flame retardant and fireproofing effect of this solution is not good. In actual application, hot pressing will cause the flame retardant hollow grid to deform and cannot maintain a hollow state. In addition, too much resin will result in poor fireproofing effect, and too little resin will result in poor compounding and poor strength.

[0005] CN103410279A uses a flexible waterproof sheet wrapped with a nano-silica aerogel felt core material as a flexible thermal insulation substrate. The flexible waterproof sheet is a flame-retardant polymer cement mortar layer containing a high-toughness glass fiber reinforced flame-retardant non-woven fabric base. The three-layer structure is consolidated into one, with a thickness of 3-10mm. This method has a good flame retardant effect and high strength, but the preparation time of the polymer cement mortar layer is as long as 28 days, and the cost of the nano-silica aerogel felt is high, so the product production cost is very high and the manufacturing cycle is long. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a lightweight flame-retardant photovoltaic backboard and a preparation method thereof. The photovoltaic backboard can achieve building B-level fire protection; compared with fireproof aluminum plates, etc., it has the characteristics of good insulation and a local discharge voltage of up to 2000V; at the same time, it also has the characteristics of high strength, flame retardancy and stability, and has good market application prospects.

[0007] The present invention provides a lightweight flame-retardant photovoltaic backboard, which is a multi-layer structure. The core layer is a modified flame-retardant polystyrene board, the upper surface layer is a thermosetting or thermoplastic composite material with thermal conductivity and fireproofing properties, the lower surface layer is a thermosetting or thermoplastic composite material, and the upper and lower surface layers are bonded to the core layer by an adhesive.

[0008] Preferably, the modified flame-retardant polystyrene board is polystyrene particles with a particle size of 0.1-5 mm, which are formed into boards through high temperature and high pressure, and then infiltrated with inorganic slurry to obtain Class A fire-retardant polystyrene boards.

[0009] More preferably, the polystyrene particles are obtained by foaming ordinary polystyrene or by foaming toughened modified polystyrene; wherein the toughened modified polystyrene comprises, by mass percentage, 20% styrene-acrylate random copolymer, 10% butadiene-styrene block copolymer, 5-10% polyethylene, 5% foaming aid, and 55%-60% polystyrene.

[0010] The inorganic slurry is a modified perfusion slurry commonly used in the industry, and the high-temperature and high-pressure board forming process is a foamed polystyrene board production process commonly used in the industry.

[0011] Preferably, the high temperature and high pressure molding process parameters are 100-150°C and 0.01-2MPa.

[0012] Preferably, the inorganic slurry is composed of 40 parts of water, 80 parts of water glass, 2 parts of polypropylene emulsion, 10 parts of magnesium hydroxide, 20 parts of barite powder and 10 parts of fly ash in parts by weight.

[0013] Preferably, the polystyrene particles have a particle size of 0.1-5 mm.

[0014] Preferably, the modified flame retardant foamed polystyrene board has a bulk density of 10-300 kg / m 3 , preferably 100-200kg / m 3 .

[0015] Preferably, the thermosetting or thermoplastic composite material with thermal conductivity and fireproofing properties comprises the following components by weight: 15-20 parts of thermal conductive and fireproofing filler, 20-30 parts of randomly oriented long fibers, and 50-70 parts of thermosetting or thermoplastic resin.

[0016] Preferably, the thermosetting or thermoplastic composite material comprises the following components by weight: 30-50 parts of randomly oriented long fibers and 50-70 parts of thermosetting or thermoplastic resin.

[0017] Preferably, the randomly oriented long fibers are one or more of glass fibers, carbon fibers, basalt fibers, nylon, and polyimide fibers; the thermosetting resin is one or more of epoxy resin, unsaturated polyester, and polyurethane; and the thermoplastic resin is one or more of PA, PP, PET, and PE.

[0018] Preferably, the adhesive is epoxy asphalt adhesive.

[0019] Preferably, the epoxy asphalt adhesive includes component A consisting of asphalt, epoxy resin, modifier, extender, filler, and component B consisting of epoxy resin curing agent.

[0020] More preferably, the epoxy asphalt adhesive consists of the following components in parts by weight:

[0021]

[0022] The modifier is a polyvinyl acetal modifier.

[0023] The compatibilizer is epoxidized soybean oil.

[0024] The filler is limestone powder.

[0025] Preferably, the total thickness of the lightweight flame-retardant photovoltaic backsheet is 12-120 mm, wherein the thickness of the core layer is 10-100 mm, and the thickness of the upper surface layer and the lower surface layer is 0.5-5 mm.

[0026] The present invention also provides a method for preparing a lightweight flame-retardant photovoltaic backsheet, comprising the following steps:

[0027] (1) preparing polystyrene foam particles, then subjecting them to high temperature and high pressure molding, and finally subjecting them to inorganic slurry infiltration to obtain a modified flame retardant polystyrene board, i.e., a core layer;

[0028] (2) blending a heat-conductive fireproof filler with a thermoplastic resin to obtain a modified thermoplastic resin, or blending a heat-conductive fireproof filler with a thermosetting resin to obtain a modified thermosetting resin; spraying and coating the cut randomly oriented long fibers with the modified thermoplastic resin or the modified thermosetting resin, heating the randomly oriented long fibers and impregnating the resin into the randomly oriented long fibers to obtain an upper surface composite material;

[0029] (3) spraying and coating the cut randomly oriented long fibers with a thermoplastic resin or a thermosetting resin, heating the randomly oriented long fibers and impregnating the resin into the randomly oriented long fibers to obtain a lower surface composite material;

[0030] (4) Apply adhesive to the surface of the core layer, and adhere the upper surface composite material and the lower surface composite material to obtain a lightweight flame-retardant photovoltaic backsheet.

[0031] Beneficial Effects

[0032] (1) The modified flame-retardant polystyrene board of the present invention is characterized in that the fireproofing reaches Class A, the mass is extremely low, the insulation performance is good, and the fireproofing and insulation are integrated;

[0033] (2) The present invention uses a heat-conductive fireproof filler as one of the components of the upper surface composite material, which further improves the fireproof performance of the photovoltaic backsheet, reduces the thermal damage of the photovoltaic cells, and increases the life of the components;

[0034] (3) The epoxy asphalt adhesive in the present invention has high bonding strength with the modified flame-retardant polystyrene board, matching thermal expansion coefficients, and reliable weather resistance;

[0035] (4) The core layer of the photovoltaic back panel of the present invention achieves building A-level fire protection, and can achieve building B-level fire protection overall. Compared with fireproof aluminum panels, etc., it has good insulation properties and a local discharge voltage of up to 2000V. It also has the characteristics of high strength and stable flame retardancy, and has good market application prospects. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended 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 fall within the scope limited by the appended claims of the application equally.

[0037] The epoxy asphalt adhesive in the embodiments and comparative examples is composed of the following components in parts by weight:

[0038]

[0039] The modifier is a polyvinyl acetal modifier.

[0040] The compatibilizer is epoxidized soybean oil.

[0041] The filler is limestone powder.

[0042] Example 1

[0043] (1) foaming toughened modified polystyrene (purchased from Arkema) with a particle size of 0.5 mm to prepare particles, then forming at 100-150° C. and 0.01-2 MPa, cutting to a thickness of 10 mm, and finally infiltrating with an inorganic slurry to obtain a Class A fireproof modified flame retardant foamed polystyrene board, i.e., the core layer;

[0044] (2) 20 parts of alumina powder as a thermal conductive fireproof filler are mixed and extruded with 50 parts of PA resin to obtain modified PA, 30 parts of cut randomly oriented long fibers are sprayed and coated with the modified PA resin, the temperature is raised to 250°C and the pressure is 2 MPa, and the resin is impregnated into the randomly oriented long fibers to obtain an upper surface reinforced composite material with a thickness of 1.0 mm. The specific scheme refers to the preparation method of CN114921093B;

[0045] (3) After spraying and coating 40 parts of cut randomly oriented long fibers and 60 parts of PA resin, the temperature was raised to 250° C. and the pressure was 2 MPa, and the resin was impregnated into the randomly oriented long fibers to obtain a 1.0 mm lower surface reinforced composite material. The specific scheme refers to the preparation method of CN114921093B;

[0046] (4) The surface of the core layer is coated with epoxy asphalt adhesive, and the upper surface composite material and the lower surface composite material are attached to obtain a lightweight flame-retardant photovoltaic backsheet.

[0047] The above-mentioned lightweight flame-retardant photovoltaic backsheet weighs 2.0kg / m 2 , fire protection grade B, partial discharge voltage up to 2000V, compressive strength 0.8MPa.

[0048] Example 2

[0049] (1) foaming toughened modified polystyrene (purchased from Arkema) with a particle size of 3 mm to prepare particles, then subjecting them to high temperature and high pressure molding, cutting them to a thickness of 30 mm, and finally subjecting them to inorganic slurry infiltration to obtain a modified flame retardant foamed polystyrene board with Class A fire protection, i.e., the core layer;

[0050] (2) 20 parts of aluminum nitride / zinc oxide composite powder (aluminum nitride: zinc oxide powder = 1:1) as a thermal conductive fireproof filler are mixed and extruded with 50 parts of PA resin to obtain modified PA, 30 parts of cut randomly oriented long fibers are sprayed and coated with the modified PA resin, the temperature is raised to 250°C, the pressure is 2MPa, and the resin is impregnated into the randomly oriented long fibers to obtain an upper surface reinforced composite material with a thickness of 1.0 mm. The specific scheme refers to the preparation method of CN114921093B;

[0051] (3) After spraying and coating 40 parts of cut randomly oriented long fibers and 60 parts of PA resin, the temperature was raised to 250° C. and the pressure was 2 MPa, and the resin was impregnated into the randomly oriented long fibers to obtain a 1.0 mm lower surface reinforced composite material. The specific scheme refers to the preparation method of CN114921093B;

[0052] (4) The surface of the core layer is coated with epoxy asphalt adhesive, and the upper surface composite material and the lower surface composite material are attached to obtain a lightweight flame-retardant photovoltaic backsheet.

[0053] The above-mentioned lightweight flame-retardant photovoltaic backsheet weighs 2.2kg / m 2 , fire protection grade B, partial discharge voltage up to 2000V, compressive strength 0.6MPa.

[0054] Example 3

[0055] (1) foaming toughened modified polystyrene (purchased from Arkema) with a particle size of 5 mm to prepare particles, then subjecting them to high temperature and high pressure molding, cutting them to a thickness of 50 mm, and finally subjecting them to inorganic slurry infiltration to obtain a Class A fireproof modified flame retardant foamed polystyrene board, i.e., the core layer;

[0056] (2) 20 parts of aluminum nitride / zinc oxide composite powder (aluminum nitride: zinc oxide powder = 1:1) as a thermal conductive fireproof filler are mixed and extruded with 50 parts of PA resin to obtain modified PA, 30 parts of cut randomly oriented long fibers are sprayed and coated with the modified PA resin, the temperature is raised to 250°C, the pressure is 2MPa, and the resin is impregnated into the randomly oriented long fibers to obtain an upper surface reinforced composite material with a thickness of 2.0 mm. The specific scheme refers to the preparation method of CN114921093B;

[0057] (3) After spraying and coating 40 parts of cut randomly oriented long fibers and 60 parts of PA resin, the temperature was raised to 250° C. and the pressure was 2 MPa, and the resin was impregnated into the randomly oriented long fibers to obtain a 2.0 mm lower surface reinforced composite material. The specific scheme refers to the preparation method of CN114921093B;

[0058] (4) The surface of the core layer is coated with epoxy asphalt adhesive, and the upper surface composite material and the lower surface composite material are attached to obtain a lightweight flame-retardant photovoltaic backsheet.

[0059] The above-mentioned lightweight flame-retardant photovoltaic backsheet weighs 2.5kg / m 2 , fire protection grade B, partial discharge voltage up to 2000V, compressive strength 0.8MPa.

[0060] Example 4

[0061] (1) foaming toughened modified polystyrene (purchased from Arkema) with a particle size of 0.5 mm to prepare particles, then forming at 100-150° C. and 0.01-2 MPa, cutting to a thickness of 10 mm, and finally infiltrating with an inorganic slurry to obtain a Class A fireproof modified flame retardant foamed polystyrene board, i.e., the core layer;

[0062] (2) 20 parts of alumina powder as a thermal conductive fireproof filler are mixed and extruded with 50 parts of epoxy resin to obtain a modified epoxy resin, 30 parts of cut randomly oriented long fibers are sprayed and coated together with the modified epoxy resin, the temperature is raised to 150° C., the pressure is 1 MPa, and the resin is impregnated into the randomly oriented long fibers to obtain an upper surface reinforced composite material with a thickness of 1.0 mm. The specific scheme refers to the preparation method of CN114921093B;

[0063] (3) After spraying and coating 40 parts of cut randomly oriented long fibers with 60 parts of epoxy resin, the temperature was raised to 150° C. and the pressure was 1 MPa, and the resin was impregnated into the randomly oriented long fibers to obtain a 1.0 mm lower surface reinforced composite material. The specific scheme refers to the preparation method of CN114921093B;

[0064] (4) The surface of the core layer is coated with epoxy asphalt adhesive, and the upper surface composite material and the lower surface composite material are attached to obtain a lightweight flame-retardant photovoltaic backsheet.

[0065] The above-mentioned lightweight flame-retardant photovoltaic backsheet weighs 2.0kg / m 2 , fire protection grade B, partial discharge voltage up to 2000V, compressive strength 1.3MPa.

[0066] Comparative Example 1

[0067] (1) Using commercially available ordinary polystyrene board as the core layer;

[0068] (2) 20 parts of alumina powder as a thermal conductive fireproof filler are mixed and extruded with 50 parts of PA resin to obtain modified PA, 30 parts of cut randomly oriented long fibers are sprayed and coated with the modified PA resin, the temperature is raised to 250°C and the pressure is 2 MPa, and the resin is impregnated into the randomly oriented long fibers to obtain an upper surface reinforced composite material with a thickness of 1.0 mm. The specific scheme refers to the preparation method of CN114921093B;

[0069] (3) After spraying and coating 40 parts of cut randomly oriented long fibers and 60 parts of PA resin, the temperature was raised to 250° C. and the pressure was 2 MPa, and the resin was impregnated into the randomly oriented long fibers to obtain a 1.0 mm lower surface reinforced composite material. The specific scheme refers to the preparation method of CN114921093B;

[0070] (4) Apply epoxy asphalt adhesive to the surface of the core layer, and adhere the upper surface composite material and the lower surface composite material to obtain a photovoltaic backsheet.

[0071] The above photovoltaic back panel weighs 2.0kg / m 2 , fire protection grade E, partial discharge voltage up to 1800V, compressive strength 0.5MPa.

[0072] Comparative Example 2

[0073] (1) foaming toughened modified polystyrene (purchased from Arkema) with a particle size of 0.5 mm to prepare particles, then subjecting them to high temperature and high pressure molding, cutting them into 10 mm thick pieces, and finally subjecting them to inorganic slurry infiltration to obtain a Class A fireproof modified flame retardant foamed polystyrene board, i.e., the core layer;

[0074] (2) After spraying and coating 40 parts of cut randomly oriented long fibers and 60 parts of PA resin, the temperature was raised to 250° C. and the pressure was 2 MPa, and the resin was impregnated into the randomly oriented long fibers to obtain an upper surface reinforced composite material with a thickness of 1.0 mm. The specific scheme refers to the preparation method of CN114921093B;

[0075] (3) After spraying and coating 40 parts of cut randomly oriented long fibers and 60 parts of PA resin, the temperature was raised to 250° C. and the pressure was 2 MPa, and the resin was impregnated into the randomly oriented long fibers to obtain a 1.0 mm lower surface reinforced composite material. The specific scheme refers to the preparation method of CN114921093B;

[0076] (4) Apply epoxy asphalt adhesive to the surface of the core layer, and adhere the upper surface composite material and the lower surface composite material to obtain a photovoltaic backsheet.

[0077] The above photovoltaic back panel weighs 2.2kg / m 2 , fire protection grade C, partial discharge voltage 1000V, compressive strength 0.6MPa.

[0078] Comparative Example 3

[0079] (1) foaming toughened modified polystyrene (purchased from Arkema) with a particle size of 0.5 mm to prepare particles, then subjecting them to high temperature and high pressure molding, cutting them into 10 mm thick pieces, and finally subjecting them to inorganic slurry infiltration to obtain a Class A fireproof modified flame retardant foamed polystyrene board, i.e., the core layer;

[0080] (2) 20 parts of alumina powder as a thermal conductive fireproof filler are mixed and extruded with 60 parts of PA resin to obtain modified PA, 20 parts of cut randomly oriented long fibers are sprayed and coated with the modified PA resin, the temperature is raised to 250° C., the pressure is 2 MPa, and the resin is impregnated into the randomly oriented long fibers to obtain an upper surface reinforced composite material with a thickness of 1.0 mm. The specific scheme refers to the preparation method of CN114921093B;

[0081] (3) After spraying and coating 40 parts of cut randomly oriented long fibers and 60 parts of PA resin, the temperature was raised to 250° C. and the pressure was 2 MPa, and the resin was impregnated into the randomly oriented long fibers to obtain a 1.0 mm lower surface reinforced composite material. The specific scheme refers to the preparation method of CN114921093B;

[0082] (4) Applying common adhesive on the surface of the core layer, pasting the upper surface composite material and the lower surface composite material on the surface, and obtaining a photovoltaic backsheet.

[0083] The above photovoltaic back panel weighs 2.0kg / m 2 , fire protection grade B, partial discharge voltage up to 2000V, compressive strength 0.3MPa.

Claims

1. A lightweight flame-retardant photovoltaic backsheet, characterized in that: The backboard is a multi-layer structure, the core layer is a modified flame-retardant polystyrene board, the upper surface layer is a thermosetting or thermoplastic composite material with thermal conductivity and fireproofing properties, the lower surface layer is a thermosetting or thermoplastic composite material, and the upper and lower surface layers and the core layer are bonded with an adhesive; The modified flame-retardant polystyrene board is a polystyrene particle with a particle size of 0.1-5 mm, which is formed into a board by high temperature and high pressure, and then infiltrated with an inorganic slurry to obtain a Class A fire-retardant polystyrene board; The thermosetting or thermoplastic composite material with heat-conducting and fire-proofing properties comprises the following components by weight: 15-20 parts of heat-conducting and fire-proofing filler, 20-30 parts of randomly oriented long fibers, and 50-70 parts of thermosetting or thermoplastic resin; The thermosetting or thermoplastic composite material of the lower surface layer comprises the following components by weight: 30-50 parts of randomly oriented long fibers and 50-70 parts of thermosetting or thermoplastic resin; The adhesive is epoxy asphalt adhesive; The polystyrene particles are obtained by foaming toughened modified polystyrene; wherein the toughened modified polystyrene comprises, by mass percentage, 20% styrene-acrylate random copolymer, 10% butadiene-styrene block copolymer, 5-10% polyethylene, 5% foaming aid, and 55%-60% polystyrene.

2. The lightweight flame-retardant photovoltaic backsheet according to claim 1, characterized in that: The randomly oriented long fibers are one or more of glass fibers, carbon fibers, basalt fibers, nylon, and polyimide fibers; the thermosetting resin is one or more of epoxy resin, unsaturated polyester, and polyurethane; and the thermoplastic resin is one or more of PA, PP, PET, and PE.

3. The lightweight flame-retardant photovoltaic backsheet according to claim 1, characterized in that: The epoxy asphalt adhesive comprises an A component consisting of asphalt, epoxy resin, a modifier, a compatibilizer, and a filler, and a B component consisting of an epoxy resin curing agent.

4. A method for preparing the lightweight flame-retardant photovoltaic backsheet according to claim 1, comprising the following steps: (1) preparing polystyrene foam particles, then subjecting them to high temperature and high pressure molding, and finally subjecting them to inorganic slurry infiltration to obtain a modified flame retardant polystyrene board, i.e., the core layer; (2) blending a heat-conductive fire-retardant filler with a thermoplastic resin to obtain a modified thermoplastic resin, or blending a heat-conductive fire-retardant filler with a thermosetting resin to obtain a modified thermosetting resin; spraying and coating the cut randomly oriented long fibers with the modified thermoplastic resin or the modified thermosetting resin, heating the randomly oriented long fibers and impregnating the resin into the randomly oriented long fibers to obtain an upper surface composite material; (3) After spraying and coating the cut randomly oriented long fibers with a thermoplastic resin or a thermosetting resin, the temperature is increased and the resin is impregnated into the randomly oriented long fibers to obtain a lower surface composite material; (4) Apply adhesive to the surface of the core layer, and adhere the upper surface composite material and the lower surface composite material to obtain a lightweight flame-retardant photovoltaic backsheet.

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