Flame-retardant and aging-resistant two-component polyurethane photovoltaic waterproof adhesive and preparation method thereof

Abstract

The present application belongs to the technical field of adhesive, and particularly relates to a kind of fire-retardant aging-resistant two-component polyurethane photovoltaic water-blocking glue and a preparation method thereof.The water-blocking glue comprises A and B components, the A component comprises raw materials such as 30-40 parts of polymeric diol, 0.05-0.1 parts of polyol crosslinking agent, 30-40 parts of filler and 0.1-0.3 parts of catalyst;the polymeric diol is a compound of phosphorus-containing polyester diol and hydroxyl-terminated polybutadiene in a molar ratio of 1:3-5;the phosphorus-containing polyester diol is prepared by reacting phosphorus oxychloride compound with C6-C10 aliphatic diol;the B component comprises raw materials such as 40-50 parts of fire-retardant polyurethane prepolymer and 30-40 parts of filler;the fire-retardant polyurethane prepolymer is prepared by reacting diisocyanate and phosphorus-containing polyester diol;the mass ratio of the A and B components satisfies that the total -OH in the phosphorus-containing polyester diol and polyol crosslinking agent in the A component is in a molar ratio of 1:1.05-1.2 with the -NCO in the fire-retardant polyurethane prepolymer in the B component.The water-blocking glue has excellent fire-retardant performance and long-term hydrolysis-resistant stability.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, specifically relating to a flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive and its preparation method. Background Technology

[0002] With the transformation of the global energy structure and the advancement of the "dual carbon" goal, solar photovoltaic power generation, as an important component of clean energy, has seen its installed capacity grow rapidly. Photovoltaic modules typically need to operate for over 25 years in harsh outdoor environments, placing extremely high demands on their long-term reliability and durability. Among these challenges, moisture erosion is one of the main factors leading to power degradation and failure of photovoltaic modules. Moisture easily penetrates the module's interior through assembly gaps in the aluminum frame, glass cover, backsheet, and junction box. On one hand, it induces potential-induced degradation (PID) in the cells, leading to a decrease in photoelectric conversion efficiency; on the other hand, it corrodes precision conductive structures such as cell grids and busbars, causing electrode oxidation and blackening, interlayer delamination, and yellowing and hydrolysis of the encapsulant film. In severe cases, it can cause short circuits or open circuits, significantly shortening the module's lifespan. Therefore, in the encapsulation and assembly stages of photovoltaic modules, especially in critical areas such as frame sealing, junction box bonding, and cable fixing, the use of high-performance water-blocking adhesives (also known as water-blocking sealants or sealants) is a key technology to ensure the long-term stable operation of the modules.

[0003] Photovoltaic water-blocking adhesives include silicone sealants, olefin polymer sealants, and polyurethane sealants. Among them, polyurethane (PU) sealants, due to their excellent adhesion, adjustable mechanical strength, and good chemical resistance, have been increasingly widely used in the field of photovoltaic module sealing and have attracted widespread attention from researchers. For example, patent CN120880308B discloses a rapid assembly process method for photovoltaic module frames, and patent CN119242247A discloses a polyurethane water-blocking adhesive for photovoltaic module frames and its preparation method.

[0004] The above-mentioned polyurethane sealants, through formulation optimization, have achieved good results in terms of adhesion and water resistance. However, photovoltaic modules face complex operating conditions such as high temperature and high pressure in practical applications, which imposes strict requirements on the fire safety of their materials. Polyurethane itself is a flammable polymer with a limiting oxygen index (LOI) of only 17-19%. Untreated polyurethane sealants pose a significant fire safety hazard, which severely limits their further application and promotion in the photovoltaic field. Therefore, it is necessary to develop a flame-retardant two-component polyurethane photovoltaic water-blocking adhesive. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive and its preparation method. Component A includes a phosphorus-containing polyester diol, which is prepared by reacting phosphoryl dichloride compounds and C6-C10 aliphatic diols as raw materials. The phosphoryl dichloride compounds introduce a phosphate-containing flame-retardant structure into the polyurethane molecular chain to improve flame-retardant properties. A compound of phosphorus-containing polyester diol and hydroxyl-terminated polybutadiene is used as the polymer diol in component A. This serves two purposes: first, to utilize the hydrophobic hydroxyl-terminated polybutadiene to reduce the hydrophilicity of the water-blocking adhesive, prevent the hydrolysis of the phosphate groups in the phosphorus-containing polyester diol, improve long-term hydrolysis resistance, and inhibit the degradation of mechanical properties; second, to synergistically optimize the polyurethane crosslinking network structure with the phosphorus-containing polyester diol, thereby improving mechanical properties while ensuring the excellent flame-retardant properties of the water-blocking adhesive. The flame-retardant polyurethane prepolymer in component B is prepared by reacting phosphorus-containing polyester diol with diisocyanate. The flame-retardant structure containing phosphate ester groups exists in the main chain of the polyurethane prepolymer in the form of covalent bonds, which can make the flame-retardant structure evenly distributed in the water-blocking polyurethane crosslinking network, so that the flame-retardant performance reaches the best.

[0006] To achieve the above objectives, the following technical solution is adopted:

[0007] A flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive includes components A and B. Component A comprises the following raw materials in parts by weight: 30-40 parts polymeric diol, 0.05-0.1 parts polyol crosslinking agent, 30-40 parts filler, and 0.1-0.3 parts catalyst; the polymeric diol is a compound of phosphorus-containing polyester diol and hydroxyl-terminated polybutadiene in a molar ratio of 1:3-5; the phosphorus-containing polyester diol is prepared by reacting a phosphoric acid dichloride compound with a C6-C10 aliphatic diol.

[0008] Component B comprises the following raw materials in parts by weight: 40-50 parts flame-retardant polyurethane prepolymer and 30-40 parts filler; the flame-retardant polyurethane prepolymer is prepared by reacting diisocyanate and phosphorus-containing polyester diol.

[0009] The mass ratio of components A and B is such that the sum of the total -OH groups in the phosphorus-containing polyester diol and polyol crosslinking agent in component A is 1:1.05-1.2, and the molar ratio of -NCO groups in the flame-retardant polyurethane prepolymer in component B is 1:1.05-1.2.

[0010] The flame-retardant polyurethane prepolymer is prepared by reacting diisocyanate and phosphorus-containing polyester diol at a molar ratio of -NCO, -OH of 6-9:1. The excess of diisocyanate makes the flame-retardant polyurethane prepolymer a mixture of terminal isocyanate oligomers and diisocyanate.

[0011] The phosphorus-containing polyester diol has a number-average molecular weight of 2000-3000 g / mol. The hydroxyl-terminated polybutadiene has a number-average molecular weight of 1400-5000 g / mol, preferably 1400-2000 g / mol. Using the compound of phosphorus-containing polyester diol and hydroxyl-terminated polybutadiene as the polymer diol of component A serves two purposes: first, to utilize the hydrophobic hydroxyl-terminated polybutadiene to reduce the hydrophilicity of the water-blocking adhesive, prevent the hydrolysis of the phosphate ester groups in the phosphorus-containing polyester diol, improve long-term hydrolytic stability, and inhibit the degradation of mechanical properties; second, to synergistically optimize the polyurethane crosslinking network structure with the phosphorus-containing polyester diol, thereby improving mechanical properties while ensuring the excellent flame-retardant properties of the water-blocking adhesive. The molar ratio of the two should be controlled at 1:3-5. If the relative amount of hydroxyl-terminated polybutadiene is too small, it cannot effectively prevent the hydrolysis of phosphate groups in phosphorus-containing polyester diol, improve long-term hydrolysis resistance, and inhibit the decay of mechanical properties. If the relative amount of hydroxyl-terminated polybutadiene is too large, the flame retardant groups cannot be evenly distributed in the water-blocking adhesive, resulting in poor flame retardant performance.

[0012] The molar ratio of the phosphoryl dichloride compound and the C6-C10 aliphatic diol is 1:1.05-1.2. The phosphoryl dichloride compound is selected from at least one of phenylphosphonic dichloride, tert-butyl dichlorophosphate, methylphosphonic dichloride, ethylphosphonic dichloride, propylphosphonic dichloride, methyl dichlorophosphate, ethyl dichlorophosphate, propyl dichlorophosphate, and phenyl dichlorophosphate. Preferably, it is selected from at least one of tert-butyl dichlorophosphate and phenylphosphonic dichloride. The C6-C10 aliphatic diol is selected from at least one of 1,6-hexanediol, 1,7-heptanediol, heptane-1,6-diol, 1,8-octanediol, 1,9-nonanediol, 1,9-decanediol, and 1,10-decanediol.

[0013] The phosphorus-containing polyester diol is prepared by a method comprising the following steps:

[0014] C6-C10 aliphatic diols, acid-binding agents, and organic solvents are mixed, and phosphoric acid dichloride compounds are added. The reaction is carried out under controlled temperature to obtain phosphorus-containing polyester diols.

[0015] The molar ratio of the phosphoryl dichloride compound and the acid-binding agent is 1:1.5-2.5. The temperature-controlled reaction is carried out at 40-80℃ for 6-12 hours. The acid-binding agent is selected from at least one of trimethylamine, triethylamine, pyridine, sodium hydroxide, potassium carbonate, and sodium carbonate. The organic solvent is selected from at least one of benzene, acetonitrile, xylene, and ethyl acetate. After the temperature-controlled reaction, the process includes washing with water, separation, drying, distillation, and post-column chromatography treatment. The washing and separation involve adding 0.5-1 times the volume of water to the reaction mixture, stirring at 150-300 rpm for 5-20 minutes, allowing the mixture to stand and separate, separating the aqueous phase, and repeating the washing 2-5 times until the pH of the washing aqueous phase reaches 6.5-7.5. The drying involves adding a drying agent to the separated organic phase. The drying agent is selected from at least one of anhydrous sodium sulfate and anhydrous magnesium sulfate. The eluent for column chromatography is a mixture of dichloromethane and ethyl acetate at a volume ratio of 3-8:1.

[0016] The flame-retardant polyurethane prepolymer is prepared by a method including the following steps: mixing phosphorus-containing polyester diol and diisocyanate, heating and reacting to obtain the flame-retardant polyurethane prepolymer.

[0017] The heating reaction is carried out at 80-100℃ for 1-3 hours with a stirring speed of 100-200 rpm.

[0018] The polyol crosslinking agent is selected from at least one of glycerol, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, and pentaerythritol.

[0019] The diisocyanate is selected from at least one of toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, 2,4'-diphenylmethane diisocyanate, naphthyl-1,5-diisocyanate, phenyl dimethyl diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and methylene bis(2-cyclohexane isocyanate).

[0020] The filler has an average particle size of 1-8 μm. The filler is selected from at least one of calcium carbonate, glass powder, and silica powder.

[0021] The catalyst is selected from one or more combinations of organotin catalysts, organobismuth catalysts, and organozinc catalysts. The organotin catalyst is selected from one or more combinations of dibutyltin dilaurate, stannous octanoate, di(dodecyl sulfide)dibutyltin, dibutyltin diacetate, dibutyltin dibutyrate, and dibutyltin dioleate. The organobismuth catalyst is selected from one or more combinations of bismuth neodecanoate, bismuth laurate, bismuth isooctanoate, and bismuth naphthenate. The organozinc catalyst is selected from one or more combinations of zinc isooctanoate, zinc neodecanoate, and zinc naphthenate.

[0022] Component A further comprises 0.03-5 parts by weight of an auxiliary agent, wherein the auxiliary agent is selected from one or a combination of two of antioxidants, light stabilizers, silane coupling agents, anti-hydrolysis agents, and pigments. There are no particular limitations on the antioxidant; any commonly used antioxidant in the art is acceptable, and it may be at least one of antioxidant 245, antioxidant 1010, antioxidant 1035, antioxidant 1076, antioxidant 1098, and antioxidant 3114.

[0023] The light stabilizer is selected from one or a combination of two of benzotriazole light stabilizers and hindered amine light stabilizers; the benzotriazole light stabilizers include, but are not limited to, one or a combination of two of Tinuvin 213 and UV-320; the hindered amine light stabilizers include, but are not limited to, one or a combination of two of (2,2,6,6-tetramethylpiperidine) sebacate and 4-benzoyloxy-2,2,6,6-tetramethylpiperidine.

[0024] The silane coupling agent is selected from at least one of epoxy silane coupling agents and alkyl silane coupling agents.

[0025] The epoxy silane coupling agent is selected from at least one of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)methyldiethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, 3-glycidyl etheroxypropylmethyldimethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane, and 3-glycidyl etheroxypropylmethyldiethoxysilane. The alkyl silane coupling agent is not particularly limited; any commonly used agent in the art is acceptable, and it can be selected from at least one of propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, n-butyltriethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, pentyltriethoxysilane, pentyltrimethoxysilane, hexyltrimethoxysilane, and decyltrimethoxysilane.

[0026] The anti-hydrolysis agent is selected from at least one of carbodiimide, dicarbodiimide, and polycarbodiimide.

[0027] The pigment is selected from at least one of carbon black, iron black, titanium dioxide, and iron oxide red.

[0028] This invention also provides a method for preparing the above-mentioned flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive, comprising the following steps:

[0029] S1 mixes polymeric diol, polyol crosslinking agent, filler, and catalyst, and dehydrates them to obtain component A;

[0030] S2 dehydrates the filler, adds flame-retardant polyurethane prepolymer, mixes well, degassing, and obtains component B.

[0031] S3A and B components are packaged separately. When using, mix components A and B thoroughly to obtain a flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive.

[0032] In step S1, the dehydration is carried out at 110-130℃ and a vacuum of 10-50 mbar until the moisture content is below 500 ppm. The mixing is carried out at a speed of 400-1200 rpm for 30-90 minutes.

[0033] In step S2, the dehydration involves heating to 115-125℃ and maintaining the temperature for 1-3 hours. The mixing involves stirring at 400-1200 rpm for 30-60 minutes. The degassing involves stirring at 50-150 rpm for 30-60 minutes under a vacuum of 10-50 mbar.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] The A component of the water-blocking adhesive of this invention includes a phosphorus-containing polyester diol, which is prepared by reacting phosphoryl dichloride compounds and C6-C10 aliphatic diols as raw materials. The phosphoryl dichloride compounds introduce a flame-retardant structure containing phosphate ester groups into the phosphorus-containing polyester diol to improve its flame-retardant properties. The polymer diol of the A component is a compound of phosphorus-containing polyester diol and hydroxyl-terminated polybutadiene. This serves two purposes: first, to utilize the hydrophobic hydroxyl-terminated polybutadiene to reduce the hydrophilicity of the water-blocking adhesive, prevent the hydrolysis of phosphate ester groups in the phosphorus-containing polyester diol, improve long-term hydrolysis resistance, and inhibit the degradation of mechanical properties; second, to synergistically optimize the polyurethane crosslinking network structure with the phosphorus-containing polyester diol, thereby improving mechanical properties while ensuring the excellent flame-retardant properties of the water-blocking adhesive. The flame-retardant polyurethane prepolymer in component B is prepared by reacting phosphorus-containing polyester diol with diisocyanate. The flame-retardant structure containing phosphate ester groups exists in the main chain of the polyurethane prepolymer in the form of covalent bonds, which can make the flame-retardant structure evenly distributed in the water-blocking polyurethane crosslinking network, so that the flame-retardant performance reaches the best. Attached Figure Description

[0036] Figure 1 Examples 1 show the UL-94 sample and the tested sample of the flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive.

[0037] Figure 2 This is a test specimen for the shear strength of the flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive of Example 1;

[0038] Figure 3 Equipment for shear strength testing;

[0039] Figure 4 A damp heat aging chamber for damp heat aging. Detailed Implementation

[0040] The present invention will be further described below with reference to specific embodiments, but is not limited to the contents of the specification. Unless otherwise specified, all "parts" mentioned in the embodiments of the present invention are parts by weight. All reagents used are commercially available in the art.

[0041] Hydroxyl-terminated polybutadiene G1000, with a number average molecular weight of 1400, is from Japan Soda.

[0042] Hydroxyl-terminated polybutadiene G2000, with a number average molecular weight of 1900, is from Japan Soda.

[0043] Calcium carbonate, with an average particle size of 5μm, is from Zhejiang Zhijin New Materials Technology Co., Ltd.

[0044] In the following examples and comparative examples, the -OH group in component A was measured by the phthalic anhydride method, and the -NCO group in component B was measured by di-n-butylamine.

[0045] Example 1

[0046] 1) 1.05 mol of 1,8-octanediol and 2.5 mol of triethylamine were added to 0.8 L of benzene and mixed well. 1 mol of tert-butyldichlorophosphoric acid was added, and the mixture was reacted at 80 °C for 6 h. After the reaction, water with an equal volume to the resulting mixture was added, and the mixture was stirred at 300 rpm for 10 min. After washing, the mixture was allowed to stand and separate into layers. The aqueous phase was removed by separation, and the washing was repeated 3 times until the pH of the washing aqueous phase reached 7. Anhydrous sodium sulfate was added to the organic phase obtained by separation, and the mixture was dried, distilled, and subjected to column chromatography to obtain a phosphorus-containing polyester diol. The eluent used for column chromatography was a mixture of dichloromethane and ethyl acetate with a volume ratio of 8:1. The number-average molecular weight of the phosphorus-containing polyester diol was determined to be 2720 g / mol by GPC.

[0047] 2) Mix phosphorus-containing polyester diol and toluene diisocyanate (TDI) at a molar ratio of -NCO to -OH of 6:1, heat to 80℃, and react for 3 hours under stirring at 100 rpm to obtain flame-retardant polyurethane prepolymer.

[0048] 3) Mix 40 kg of polymeric diol, 0.1 kg of trimethylolpropane, 40 kg of calcium carbonate, 0.1 kg of stannous octoate, and 0.5 kg of carbon black at 500 rpm for 60 min. Dehydrate to 300 ppm moisture content at 110℃ and 50 mbar vacuum to obtain component A. The polymeric diol is a compound of phosphorus-containing polyester diol and hydroxyl-terminated polybutadiene G2000 in a molar ratio of 1:3.

[0049] 4) Heat to 115℃ to dehydrate 40kg of calcium carbonate for 3 hours, add 40kg of flame-retardant polyurethane prepolymer and stir at 500rpm for 30 minutes to mix evenly, then stir at 100rpm under vacuum of 50mbar for 40 minutes to degas and obtain component B.

[0050] 5) Components A and B are packaged separately. When using, mix components A and B thoroughly. The mass ratio of components A and B should be such that the total -OH in the phosphorus-containing polyester diol and crosslinking agent trimethylolpropane in component A is 1:1.2, and the molar ratio of -NCO in the flame-retardant polyurethane prepolymer in component B is 1:1.2. This yields a flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive.

[0051] Example 2

[0052] The rest is the same as in Example 1, except that in step 1), tert-butyl dichlorophosphoric acid is replaced with an equimolar amount of phenylphosphonic acid dichlorophosphoric acid. The number-average molecular weight of the phosphorus-containing polyester diol was determined to be 2650 g / mol by GPC.

[0053] Example 3

[0054] The rest is the same as in Example 1, except that in step 1), tert-butyl dichlorophosphate is replaced with an equimolar amount of phenyl dichlorophosphate. The number-average molecular weight of the phosphorus-containing polyester diol was determined to be 2580 g / mol by GPC.

[0055] Example 4

[0056] The rest is the same as in Example 1, except that in step 1), 1,6-hexanediol is used instead of 1,8-octanediol in an equimolar amount. The number-average molecular weight of the phosphorus-containing polyester diol was determined to be 2360 g / mol by GPC.

[0057] Example 5

[0058] The rest is the same as in Example 1, except that in step 1), 1,10-decanediol is used instead of 1,8-octandiol in an equimolar amount. The number-average molecular weight of the phosphorus-containing polyester diol was determined to be 2940 g / mol by GPC.

[0059] Example 6

[0060] The rest is the same as in Example 1, except that in step 1), the amount of 1,8-octanediol used is 1.2 mol. The number-average molecular weight of the phosphorus-containing polyester diol was determined to be 2250 g / mol by GPC.

[0061] Example 7

[0062] The rest is the same as in Example 1, except that in step 3), the polymer diol is composed of phosphorus-containing polyester diol and hydroxyl-terminated polybutadiene G2000 in a molar ratio of 1:5.

[0063] Example 8

[0064] The rest is the same as in Example 1, except that in step 3), hydroxyl-terminated polybutadiene G1000 is replaced with an equimolar amount of hydroxyl-terminated polybutadiene G2000.

[0065] Example 9

[0066] The rest is the same as in Example 1, except that in step 2), the phosphorus-containing polyester diol and toluene diisocyanate are mixed at a molar ratio of -NCO to -OH of 9:1 for subsequent reaction.

[0067] Example 10

[0068] 1) 1.2 mol of 1,8-octanediol and 1.5 mol of sodium carbonate were added to 0.8 L of benzene and mixed well. 1 mol of tert-butyldichlorophosphoric acid was added, and the mixture was reacted at 80 °C for 6 h. After the reaction was completed, water with an equal volume to the resulting mixture was added and stirred at 300 rpm for 10 min. After washing, the mixture was allowed to stand and separate into layers. The aqueous phase was removed by separation, and the washing was repeated 3 times until the pH of the washing aqueous phase reached 7. Anhydrous sodium sulfate was added to the organic phase obtained by separation, and the mixture was dried, distilled, and subjected to column chromatography to obtain a phosphorus-containing polyester diol. The eluent used for column chromatography was a mixture of dichloromethane and ethyl acetate with a volume ratio of 6:1. The number-average molecular weight of the phosphorus-containing polyester diol was determined to be 2180 g / mol by GPC.

[0069] 2) Mix phosphorus-containing polyester diol and toluene diisocyanate (TDI) at a molar ratio of -NCO to -OH of 9:1, heat to 80℃, and react for 3 hours under stirring at 100 rpm to obtain flame-retardant polyurethane prepolymer.

[0070] 3) Mix 30 kg of polymeric diol, 0.1 kg of trimethylolpropane, 40 kg of calcium carbonate, 0.1 kg of stannous octoate, and 0.5 kg of carbon black at 500 rpm for 60 min. Dehydrate to 300 ppm moisture content at 110 °C and 50 mbar vacuum to obtain component A. The polymeric diol is a compound of phosphorus-containing polyester diol and hydroxyl-terminated polybutadiene G2000 in a molar ratio of 1:3.

[0071] 4) Heat to 115℃ to dehydrate 40kg of calcium carbonate for 3 hours, add 50kg of flame-retardant polyurethane prepolymer and stir at 500rpm for 30 minutes to mix evenly, then stir at 100rpm under vacuum of 50mbar for 40 minutes to degas and obtain component B.

[0072] 5) Components A and B are packaged separately. When using, mix components A and B thoroughly. The mass ratio of components A and B should be such that the total -OH in the phosphorus-containing polyester diol and crosslinking agent trimethylolpropane in component A is 1:1.05, and the molar ratio of -NCO in the flame-retardant polyurethane prepolymer in component B is 1:1.05. This yields a flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive.

[0073] Comparative Example 1

[0074] The rest is the same as in Example 1, except that in step 3), the polymer diol is composed of phosphorus-containing polyester diol and hydroxyl-terminated polybutadiene G2000 in a molar ratio of 1:2.

[0075] Comparative Example 2

[0076] The rest is the same as in Example 1, except that in step 3), the polymer diol is composed of phosphorus-containing polyester diol and hydroxyl-terminated polybutadiene G2000 in a molar ratio of 1:6.

[0077] The flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesives prepared in the above examples and comparative examples were cured for 7 days at 25°C and 55% relative humidity, and the following performance tests were conducted:

[0078] 1. UL-94: Tested according to standard GB / T 2408-2021, determination of flammability of plastics, horizontal and vertical methods.

[0079] 2. Shear strength: Tested according to standard GB / T 7124-2008 Determination of tensile shear strength of adhesives (rigid material to rigid material), aluminum / glass substrate.

[0080] 3. Damp heat aging: The shear strength test specimens were damp heat aged for 1000 h at 85℃ / 85%RH, and the shear strength was retested. The damp heat aging strength loss rate was calculated as follows: damp heat aging strength loss rate (%) = [(initial shear strength - shear strength after damp heat aging) / initial shear strength] × 100%.

[0081] 4. Water vapor transmission rate: Refer to standard GB / T 26253-2010 Determination of water vapor transmission rate of plastic films and sheets, infrared detector method.

[0082] Table 1 Performance Test Results

[0083]

[0084] Table 1 shows that the water-based adhesive prepared in this application exhibits excellent flame retardant properties, resistance to damp heat aging, water resistance, and mechanical properties. Examples 1, 4, 5, and 1-3 demonstrate that the number of carbon atoms in the C6-C10 aliphatic diols and the side group type of the phosphoryl dichloride compound also play a crucial role in inhibiting the degradation of mechanical properties during damp heat aging. The reason for this is speculated to be that the carbon chain length of the C6-C10 aliphatic diols and the side group structure of the phosphoryl dichloride compound jointly affect the hydrophobicity of the phosphorus-containing polyester diol and the hydrolytic stability of the phosphate ester bond. The longer the carbon chain of the diol, the higher the proportion of hydrophobic methylene segments within the phosphorus-containing polyester diol molecule, corresponding to an increased proportion of non-polar segments in the polyurethane adhesive layer. This facilitates the formation of continuous hydrophobic regions, hindering the diffusion of water vapor into the adhesive layer and reducing the hydrolytic attack of water molecules on the urethane and phosphate ester bonds, thereby reducing the loss of mechanical strength after damp heat aging. The side groups of phosphoric acid dichloro monomers can form a hydrophobic barrier around the phosphate ester bond. Among them, the hydrophobic effect of phosphoric acid dichlorophosphoric acid and phosphoric acid dichlorophosphoric acid containing tert-butyl side groups and phenyl side groups and phosphoric acid dichlorophosphoric acid is better than that of other hydrolyzable side groups, preventing water molecules from contacting and hydrolyzing the phosphate ester bond, so that the mechanical decay of the adhesive layer during the wet heat aging process is not obvious.

Claims

1. A flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive, characterized in that, The product comprises components A and B. Component A includes the following raw materials in parts by weight: 30-40 parts polymeric diol, 0.05-0.1 parts polyol crosslinking agent, 30-40 parts filler, and 0.1-0.3 parts catalyst; the polymeric diol is a compound of phosphorus-containing polyester diol and hydroxyl-terminated polybutadiene in a molar ratio of 1:3-5; the phosphorus-containing polyester diol is prepared by reacting a phosphoric acid dichloride compound with a C6-C10 aliphatic diol. Component B comprises the following raw materials in parts by weight: 40-50 parts flame-retardant polyurethane prepolymer and 30-40 parts filler; the flame-retardant polyurethane prepolymer is prepared by reacting diisocyanate and phosphorus-containing polyester diol. The mass ratio of components A and B is such that the sum of the total -OH groups in the phosphorus-containing polyester diol and polyol crosslinking agent in component A is 1:1.05-1.2, and the molar ratio of -NCO groups in the flame-retardant polyurethane prepolymer in component B is 1:1.05-1.

2.

2. The flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive according to claim 1, characterized in that, The flame-retardant polyurethane prepolymer is prepared by reacting diisocyanate and phosphorus-containing polyester diol at a molar ratio of -NCO, -OH of 6-9:

1.

3. The flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive according to claim 1, characterized in that, The phosphorus-containing polyester diol has a number-average molecular weight of 2000-3000 g / mol; the hydroxyl-terminated polybutadiene has a number-average molecular weight of 1400-5000 g / mol, preferably 1400-2000 g / mol.

4. The flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive according to claim 1, characterized in that, The molar ratio of the phosphoryl dichloride compound and the C6-C10 aliphatic diol is 1:1.05-1.

2.

5. The flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive according to claim 1, characterized in that, The phosphoryl dichloride compound is selected from at least one of phenylphosphonic dichloride, tert-butyl dichlorophosphate, methylphosphonic dichloride, ethylphosphonic dichloride, propylphosphonic dichloride, methyl dichlorophosphate, ethyl dichlorophosphate, propyl dichlorophosphate, and phenyl dichlorophosphate; preferably at least one of tert-butyl dichlorophosphate and phenylphosphonic dichloride; the C6-C10 aliphatic diol is selected from at least one of 1,6-hexanediol, 1,7-heptanediol, heptane-1,6-diol, 1,8-octanediol, 1,9-nonanediol, 1,9-decanediol, and 1,10-decanediol.

6. The flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive according to claim 1, characterized in that, The phosphorus-containing polyester diol is prepared by a method comprising the following steps: mixing a C6-C10 aliphatic diol, an acid-binding agent and an organic solvent, adding a phosphorus dichloride compound, and reacting under controlled temperature to obtain the phosphorus-containing polyester diol.

7. The flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive according to claim 1, characterized in that, The flame-retardant polyurethane prepolymer is prepared by a method including the following steps: mixing phosphorus-containing polyester diol and diisocyanate, heating and reacting to obtain the flame-retardant polyurethane prepolymer.

8. The flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive according to claim 1, characterized in that, The diisocyanate is selected from at least one of toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, 2,4'-diphenylmethane diisocyanate, naphthyl-1,5-diisocyanate, phenyl dimethyl diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and methylene bis(2-cyclohexane isocyanate).

9. The flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive according to claim 1, characterized in that, The polyol crosslinking agent is selected from at least one of glycerol, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, and pentaerythritol; the filler has an average particle size of 1-8 μm; the filler is selected from at least one of calcium carbonate, glass powder, and silica powder; the catalyst is selected from one or more combinations of organotin catalysts, organobismuth catalysts, and organozinc catalysts.

10. The preparation method of the flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive according to any one of claims 1-9, characterized in that, Includes the following steps: S1 mixes polymeric diol, polyol crosslinking agent, filler, and catalyst, and dehydrates them to obtain component A; S2 dehydrates the filler, adds flame-retardant polyurethane prepolymer, mixes well, degassing, and obtains component B. S3A and B components are packaged separately. When using, mix components A and B thoroughly to obtain a flame-retardant and aging-resistant two-component polyurethane photovoltaic water-blocking adhesive.

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