Butyl hot melt adhesive for heat-conducting and water-blocking photovoltaic module and preparation method thereof

Abstract

The application discloses a butyl hot melt adhesive for heat-conducting and water-blocking photovoltaic components and a preparation method thereof. Raw material formula of the butyl hot melt adhesive comprises the following raw materials in parts by weight: EVA resin 5-15, butyl rubber 20-30 parts, acrylic resin 40-60 parts, heat-conducting filler 80-90 parts, silane coupling agent 0.3-0.5 parts, semi-reinforcing agent 3-6 parts, paraffin 4-8 parts, white oil 3-5 parts and coumarone resin 2-6 parts. The application can effectively prevent photovoltaic component heat accumulation from causing material aging and component failure under the influence of long sunlight irradiation, acid rain corrosion and other external factors, simultaneously prevents external water vapor from entering the battery piece and the junction box, and effectively solves the problems of leakage damage caused by corrosion and damage under long-time sunlight irradiation in a harsh environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat-conducting waterproof materials, in particular to a butyl hot melt adhesive for heat-conducting and waterproof photovoltaic modules and a preparation method thereof. BACKGROUND

[0002] In recent years, with the increasing demand for clean energy and renewable resources, the photovoltaic cell industry in China has developed rapidly and gradually moved towards industrialization. Technological progress has become an important factor in reducing the cost of solar photovoltaic power generation and promoting the development of the crystalline silicon solar cell industry and market.

[0003] Solar cell modules are the core part of solar power systems, mainly composed of solar cell pieces, sealing glue, glass, backboard, junction box, etc., and have the function of converting solar energy into direct current. However, the use environment of solar cell modules is often outdoor environment, accompanied by relatively harsh application scenarios such as heat accumulation caused by high temperature environment, water vapor convection, humidity, dust and sand, light time, which will soon lead to the aging of the sealing glue and loss of function. The weather with high temperature and high humidity is increasing, the light is sufficient and the water erosion is intensified, and the cost caused by environmental damage is increasing rapidly year by year. In order to effectively solve this problem, higher requirements must be put forward for the heat dissipation of the packaging technology of the battery pack, and the heat conduction and water vapor barrier properties of the sealing glue of the solar cell module must be strengthened.

[0004] Module line is also called packaging line, and packaging is a key step in solar cell production. Without good packaging process, even the best battery cannot produce good module board. The sub-packaging of the battery not only ensures the service life of the battery, but also increases the impact strength of the battery. The high quality and long life of the product are the key to winning customer satisfaction, so the packaging quality of the assembled board is very important. The current module packaging technology on the market mainly adopts two packaging processes, the first internal structure adopts EVA or PVB hot melt adhesive to ensure the vacuum degree and air tightness of the battery piece, and the second adopts silicone sealing glue to bond the external aluminum frame to achieve a certain use strength and ensure the sealing of the module. However, in a high temperature environment, heat accumulation to a certain extent will cause material aging and loss of sealing effect.

[0005] Currently, butyl rubber and silicone rubber are widely used due to their long-lasting sealing, good chemical stability, and good glass-metal bonding performance. However, this technical solution cannot solve the problem of heat accumulation caused by long-term exposure to sunlight, which will cause thermal stress concentration of the junction box and the frame aluminum plate, accelerate material aging, and cause bonding failure. At the same time, the water vapor transmission rate increases sharply under high temperature, corrodes the internal structure of the battery pack, and seriously affects the working stability of the photovoltaic module.

[0006] In order to ensure that the adhesive material can be used in high temperature and high humidity environment, a butyl polymer with low water vapor transmission rate is usually used, which can only solve the good water resistance in low temperature environment. In high temperature environment such as desert environment, the sunlight can reach 70-80 degrees Celsius, and the accumulation of heat can accelerate the aging of the material, which is difficult to consider all application scenarios. Moreover, when the high temperature and high humidity environment causes the unreacted small molecules in the adhesive material to hydrolyze with water in the air, it is difficult to ensure the excellent water resistance of the sealing material.

[0007] The butyl hot melt adhesive with heat conduction function not only has the function of adhesion, but also can block water vapor from invading the internal components in high and low temperature environment, so that the components can run stably. SUMMARY

[0008] The butyl hot melt adhesive for heat-conducting and water-resisting photovoltaic components and the preparation method provided by the application solve the problems in the prior art. The preparation raw materials include the following components in parts by weight: EVA resin 5-15, butyl rubber 20-30 parts, acrylic resin 40-60 parts, heat-conducting filler 80-90 parts, silane coupling agent 0.3-0.5 parts, semi-reinforcing agent 3-6 parts, paraffin 4-8 parts, white oil 3-5 parts, and coumarone resin 2-6 parts.

[0009] Preferably, the EVA resin has a VA content of 18-33 and a melt index of 6-800.

[0010] Preferably, the butyl rubber is one or a combination of ordinary butyl rubber, chlorinated butyl rubber, and brominated butyl rubber, and has a viscosity-average molecular weight of (35-45)*104.

[0011] Preferably, the acrylic resin is a thermoplastic acrylic resin, and has a number-average molecular weight of 75000-150000.

[0012] Preferably, the heat-conducting filler is selected from one or more of spherical aluminum oxide, needle-shaped zinc oxide, flaky boron nitride, light calcium carbonate, spherical silicon dioxide, aluminum nitride, and talc powder.

[0013] Preferably, the silane coupling agent is one or more of trivinylsilane, vinyltris(dimethylsiloxy)silane, vinyltris(2-methoxyethoxy)silane, and vinylsilane.

[0014] Further preferably, the silane coupling agent is one or more products of grafting one or more of trivinylsilane, vinyltris(dimethylsiloxy)silane, vinyltris(2-methoxyethoxy)silane or vinylsilane by one or more radical polymerization initiated by one or more of azobisisobutyronitrile, dibenzoyl peroxide, tert-butyl peroxy pivalate or potassium persulfate; one or more of the oil-wetting modified products modified by one or more radical polymerization initiated by one or more of azobisisobutyronitrile, dibenzoyl peroxide, tert-butyl peroxy pivalate or potassium persulfate.

[0015] Preferably, the semi-reinforcing agent comprises carbon black and fumed white carbon black.

[0016] Preferably, the paraffin wax is one or more of fully refined paraffin wax, semi-refined paraffin wax and crude paraffin wax.

[0017] Preferably, the relative density of the coumarone resin is 1.05-1.15 g / cm3.

[0018] According to another aspect of the present application, there is provided a preparation method of a butyl hot melt adhesive for a heat-conducting and water-resistant photovoltaic module, comprising the following steps:

[0019] (1) Preheat the kneader to 70-90℃, and cut the butyl rubber into small pieces using scissors.

[0020] (2) Add the EVA resin and the thermoplastic acrylic resin into the kneader and plasticize for 20-45 min;

[0021] (3) Increase the temperature of the kneader to 80-90℃, and add the heat-conducting filler, the silane coupling agent, the semi-reinforcing agent, the paraffin wax, the white oil and the coumarone resin, and continue kneading for 30-50 min;

[0022] (4) Increase the temperature of the kneader to 130-150℃, and vacuumize the internal air pressure to 0.08-0.1 MPa, and knead at a temperature of 140-180℃ for 40-60 min to obtain a uniform rubber compound, and discharge the rubber compound to obtain the butyl hot melt adhesive for a heat-conducting and water-resistant photovoltaic module.

[0023] The present application has the following advantages:

[0024] The main principle of the present application is that the heat-conducting filler can form a chemical bond between the filler and the matrix resin after modification by a silane coupling agent, thereby enhancing the interaction between the filler and the matrix resin, reducing phonon scattering at the interface, and improving the thermal conductivity of the hot melt adhesive. After modification, the surface energy of the heat-conducting filler is reduced, and agglomeration is not easy to occur. After the filler is used in combination, more effective heat-conducting channels can be formed in the hot melt adhesive system. At the same time, the molecular chain entanglement of butyl rubber can block the penetration of water vapor, so that the photovoltaic module hot melt adhesive has good thermal conductivity, low water vapor transmission rate, and good heat resistance and ultraviolet aging resistance during use, thereby increasing the service life of the photovoltaic module.

[0025] In addition, by using the heat-conducting filler in combination, the problem of agglomeration of the nano filler in the matrix can be greatly improved, more effective heat-conducting networks can be established, and the interface region can be improved, thereby reducing phonon scattering at the interface and improving the thermal conductivity of the heat-conducting composite material. At the same time, the arrangement of isoprene and isobutene side methyl groups in butyl rubber can block the penetration of water vapor, effectively prevent the oxidation of active groups, and thereby accelerate the aging of the material. The heat-conducting network dissipates heat, thereby improving the lap strength, wet heat aging lap strength, barrier efficiency, and insulation of the butyl hot melt adhesive for solar photovoltaic modules. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present application more clear, the method of the present application is described below through specific examples, which is only used to explain the present application and does not limit the present application.

[0027] The word "preferred" in the present application means that in some cases certain embodiments of the present application can provide certain benefits, advantages or objective effects. However, other embodiments can also be preferred in the same or other cases. In addition, the description of one or more preferred embodiments does not mean that other embodiments are not available, nor is it intended to exclude other embodiments from the scope of the present application.

[0028] The present application provides a butyl hot melt adhesive for heat-conducting and water-blocking photovoltaic modules, and the preparation raw materials include the following components in parts by weight: EVA resin 5-15, butyl rubber 20-30 parts, acrylic resin 40-60 parts, heat-conducting filler 80-90 parts, silane coupling agent 0.3-0.5 parts, semi-reinforcing agent 3-6 parts, paraffin 4-8 parts, white oil 3-5 parts, and coumarone resin 2-6 parts.

[0029] In one embodiment, the EVA resin has a VA content of 18-33 and a melt index of 6-800.

[0030] In an embodiment, the butyl rubber is one or more of a regular butyl rubber, chlorinated butyl rubber, and brominated butyl rubber in combination, having a viscosity average molecular weight of (35-45)*104.

[0031] In an embodiment, the acrylic resin is a thermoplastic acrylic resin having a number average molecular weight of 75000-150000.

[0032] In a preferred embodiment, the thermally conductive filler is selected from one or more of spherical alumina, acicular zinc oxide, flaky boron nitride, light calcium carbonate, spherical silica, aluminum nitride, talc powder.

[0033] In a preferred embodiment, the silane coupling agent is one or more of tri-vinylsilane, vinyl-tris(dimethylsiloxy)silane, vinyl-tris(2-methoxyethoxy)silane, and vinylsilane.

[0034] In an embodiment, the semi-reinforcing agent comprises carbon black and fumed white carbon.

[0035] In an embodiment, the paraffin wax is one or more of a fully refined paraffin wax, a semi-refined paraffin wax, and a crude paraffin wax.

[0036] In an embodiment, the coumarone resin has a relative density of 1.05-1.15 g / cm 3 .

[0037] In an embodiment, the spherical alumina, aluminum nitride, and acicular zinc oxide are in a weight ratio of 0.6:1:2.

[0038] In an embodiment, the flaky boron nitride and light calcium carbonate are in a weight ratio of 0.8:1.

[0039] In an embodiment, the light calcium carbonate, talc powder, and spherical silica are in a weight ratio of 2:1:2.

[0040] In an embodiment, the semi-reinforcing agent comprises carbon black and fumed white carbon.

[0041] In an embodiment, the carbon black and fumed white carbon are in a weight ratio of 2:1.

[0042] In an embodiment, the carbon black and fumed white carbon are in a weight ratio of 6:0.6.

[0043] In an embodiment, the carbon black and fumed white carbon are in a weight ratio of 4:0.8.

[0044] In an embodiment, the other auxiliary agent comprises a coumarone resin and white oil.

[0045] In one embodiment, the weight ratio of the coumarone resin and white oil is 1.2:1.8.

[0046] In one preferred embodiment, the weight ratio of the coumarone resin and white oil is 0.8:2.6.

[0047] In one embodiment, the weight ratio of the coumarone resin and white oil is 1:2.8.

[0048] The butyl hot melt adhesive for heat-conducting and water-resisting photovoltaic module comprises the following components in parts by weight: EVA resin 5-15 parts by weight, butyl rubber 25-29 parts by weight, acrylic resin 40-50 parts by weight, silane coupling agent 0.3-0.5 parts, boron nitride 30-50 parts by weight, light calcium carbonate 10-20 parts by weight, white carbon black 0.2-1.0 parts by weight, carbon black 3-6 parts by weight, paraffin wax 4-8 parts by weight, white oil 3-5 parts by weight, and coumarone resin 2-6 parts.

[0049] In one embodiment, the butyl hot melt adhesive for heat-conducting and water-resisting photovoltaic module comprises the following components in parts by weight: EVA resin 10 parts, butyl rubber 25 parts, acrylic resin 40 parts, silane coupling agent 0.4 parts, boron nitride 30 parts, light calcium carbonate 10 parts, white carbon black 0.8 parts, carbon black 6.0 parts, paraffin wax 4.6 parts, white oil 3.6 parts, and coumarone resin 3.0 parts.

[0050] The second aspect of the present application provides a preparation method of the butyl hot melt adhesive for heat-conducting and water-resisting photovoltaic module, comprising the following steps:

[0051] (1) Preheat the kneader to 70-90°C, and cut the butyl rubber into small pieces using scissors.

[0052] (2) Add the EVA resin and thermoplastic acrylic resin into the kneader and plasticize for 20-45 min;

[0053] (3) Increase the temperature of the kneader to 80-90°C, and add the heat-conducting filler, silane coupling agent, semi-reinforcing agent, paraffin wax, white oil, and coumarone resin, and continue kneading for 30-50 min;

[0054] (4) Increase the temperature of the kneader to 130-150°C, and vacuumize the internal pressure to 0.08-0.1 MPa, and knead at a temperature of 140-180°C for 40-60 min to obtain a uniform glue, and discharge to obtain the butyl hot melt adhesive for heat-conducting and water-resisting photovoltaic module.

[0055] The silane coupling agent in the examples 1-3 and the comparative example is trivinylsilane.

[0056] Example 1

[0057] A kind of butyl hot melt adhesive for heat-conducting water-resisting photovoltaic module, by portion, preparation raw material includes the following components: EVA resin 11 parts, butyl rubber 30 parts, acrylic resin 50 parts, light calcium carbonate 25 parts, boron nitride 40 parts, silicon dioxide 15 parts, silane coupling agent 0.5 parts, white carbon black 1 part, carbon black 3 parts, paraffin 4 parts, white oil 3 parts and coumarone resin 2 parts.

[0058] The preparation method of butyl hot melt adhesive for heat-conducting water-resisting photovoltaic module includes the following steps:

[0059] (1) the kneader is preheated to 80 DEG C, and butyl rubber is cut into small pieces using scissors.

[0060] (2) EVA resin and thermoplastic acrylic resin are added to the kneader and plasticized for 35 min;

[0061] (3) the temperature of the kneader is raised to 85 DEG C, and heat-conducting filler, silane coupling agent, semi-reinforcing agent, paraffin, white oil, coumarone resin are added, and continue to knead for 40 min;

[0062] (4) the temperature of the kneader is raised to 140 DEG C, vacuum is extracted to make the internal air pressure to 0.09 MPa, and knead for 55 min at a temperature of 170 DEG C, to obtain uniform glue, discharge, to obtain butyl hot melt adhesive for heat-conducting water-resisting photovoltaic module.

[0063] Example 2

[0064] A kind of butyl hot melt adhesive for heat-conducting water-resisting photovoltaic module, by portion, preparation raw material includes the following components: EVA resin 15 parts, butyl rubber 29 parts, acrylic resin 50 parts, spherical alumina 35 parts, silicon dioxide 35 parts, needle-like zinc oxide 30 parts, silane coupling agent 0.4 parts, white carbon black 2 parts, carbon black 0.5 parts, paraffin 5 parts, white oil 4 parts and coumarone resin 5 parts.

[0065] The preparation method is same as example 1.

[0066] Example 3

[0067] A kind of butyl hot melt adhesive for heat-conducting water-resisting photovoltaic module, by portion, preparation raw material includes the following components: EVA resin 15 parts, butyl rubber 25 parts, acrylic resin 40 parts, zinc oxide 30 parts, spherical alumina 30 parts, aluminum nitride 25 parts, silane coupling agent 0.3 parts, white carbon black 2 parts, carbon black 2 parts, paraffin 4 parts, white oil 5 parts and coumarone resin 6 parts.

[0068] The preparation method is same as example 1.

[0069] Comparative example 1

[0070] Based on example 1, silane coupling agent is not included in the components.

[0071] Comparative Example 2

[0072] Based on Example 1, butyl rubber is not included in the component.

[0073] Comparative Example 3

[0074] Based on Example 1, white oil is not included in the component.

[0075] Example 4

[0076] Based on Example 1, the silane coupling agent is isoprene grafted trivinylsilane by free radical polymerization, the initiator is azobisisobutyronitrile, the mass ratio of isoprene to trivinylsilane is 1:1, azobisisobutyronitrile accounts for 0.7% of the total mass, and the reaction is carried out at 80℃ for 3 hours.

[0077] The performance test of the butyl hot melt adhesive for the heat-conducting water-resistant photovoltaic module of the application is shown in Table 1.

[0078] Table 1 Comparison of related properties of material examples of the application

[0079]

[0080] It can be seen from Example 1 and Comparative Examples 1-3 that in the absence of a silane coupling agent, the thermal conductivity of the material decreases, which may be because the nanoparticles agglomerate due to their high surface energy during filling, resulting in fewer thermal conduction paths in the material and thus a decrease in heat conduction efficiency. Secondly, the phonon scattering at the interface between the filler and the matrix resin is more serious, affecting heat conduction. In the absence of butyl rubber, the hindering effect of water vapor molecules decreases due to the absence of the tightly arranged methyl structure of butyl rubber. The addition of white oil in the material increases the compatibility of the filler and the matrix, but the effect is not very obvious.

[0081] It can be seen from Example 1 and Example 4 that after modification of the silane coupling agent, the thermal conductivity and shear strength of the material are improved to a certain extent, which may be because after grafting small molecules, the compatibility between silicon series molecules and carbon-based molecules improves, and secondly, a strong interaction is formed between the filler and the matrix. At the same time, the presence of the silane coupling agent strengthens the interaction between the matrix and the filler, not only reducing the phonon scattering at the interface between the filler and the matrix, but also reducing the agglomeration of nanoparticles and increasing more thermal conduction paths, thereby improving the strength of the material while increasing the thermal conductivity.

[0082] It is easy for those skilled in the art to understand that the above description is only a preferred embodiment of the application and is not intended to limit the application, and any modifications, equivalent replacements and improvements made within the spirit and principles of the application should be included in the protection scope of the application.

Claims

1. A butyl hot melt adhesive for thermally conductive and water-blocking photovoltaic modules, characterized in that, The raw materials for preparation, by weight, contain the following components: 5-15 parts of EVA resin, 20-30 parts of butyl rubber, 40-60 parts of acrylic resin, 80-90 parts of thermally conductive filler, 0.3-0.5 parts of silane coupling agent, 3-6 parts of semi-reinforcing agent, 4-8 parts of paraffin wax, 3-5 parts of white oil, and 2-6 parts of coumarone resin. The silane coupling agent is a product obtained by grafting trivinylsilane, vinyltris(dimethylsiloxane)silane, or vinyltris(2-methoxyethoxy)silane onto isoprene via free radical polymerization with azobisisobutyronitrile as the initiator; the paraffin is one or more of fully refined paraffin, semi-refined paraffin, and crude paraffin.

2. The butyl hot melt adhesive for thermally conductive and water-blocking photovoltaic modules according to claim 1, characterized in that, The EVA resin has a VA content of 18-33% and a melt index of 600-800 g / 10min; The butyl rubber is one or more combinations of chlorinated butyl rubber and brominated butyl rubber, and its viscosity-average molecular weight is 35 × 10⁻⁶. 4 -45×10 4 .

3. The butyl hot melt adhesive for thermally conductive and water-blocking photovoltaic modules according to claim 1, characterized in that, The acrylic resin is a thermoplastic acrylic resin with a number average molecular weight of 75,000 to 150,000.

4. The butyl hot melt adhesive for thermally conductive and water-blocking photovoltaic modules according to claim 1, characterized in that, The thermally conductive filler is selected from one or more of the following: spherical alumina, needle-shaped zinc oxide, flake-shaped boron nitride, light calcium carbonate, spherical silicon dioxide, aluminum nitride, and talc.

5. The butyl hot melt adhesive for thermally conductive and water-blocking photovoltaic modules according to claim 1, characterized in that, The semi-reinforcing agent comprises carbon black and fumed silica.

6. The butyl hot melt adhesive for thermally conductive and water-blocking photovoltaic modules according to claim 1, characterized in that, The relative density of the coumarone resin is 1.05–1.15 g / cm³. 3 .

7. The method for preparing butyl hot melt adhesive for thermally conductive and water-blocking photovoltaic modules according to any one of claims 1 to 6, characterized in that, Includes the following steps: (1) Preheat the kneader to 70-90℃ and use scissors to cut the butyl rubber into small pieces; (2) Add EVA resin and acrylic resin to a kneader and plasticize for 20 minutes. 45min; (3) Raise the temperature of the kneader to 80°C. At 90℃, add thermally conductive filler, silane coupling agent, semi-reinforcing agent, paraffin wax, white oil, and coumarone resin, and continue kneading for 30-50 minutes. (4) Raise the temperature of the kneader to 130°C At 150℃, a vacuum was drawn to reduce the internal air pressure to 0.

08. 0.1 MPa, continue heating to 140 Knead at 180℃ for 40 minutes After 60 minutes, a uniform adhesive was obtained, and the material was discharged to obtain butyl hot melt adhesive for thermally conductive and water-blocking photovoltaic modules.

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