Skin membrane preparation process based on EVA (Ethylene Vinyl Acetate) material

Abstract

The invention discloses a skin membrane preparation process based on an EVA (Ethylene Vinyl Acetate) material, which comprises the following steps: firstly, taking EVA as a substrate material, and adding a cross-linking agent, an assistant cross-linking agent, a silane coupling agent, an antioxidant, a deacidification agent and an anti-PID (Potential Induced Degradation) reagent; and after the mixed EVA particles are subjected to curtain coating and embossing by an extruder, traction, flattening and rolling are performed, and the EVA particles enter irradiation equipment to be subjected to irradiation treatment, rolling and slitting. Wherein the skin membrane is prepared from the following particle components in parts by mass: 40 to 60 parts of EVA particles with a high melt index, 40 to 60 parts of EVA particles with a low melt index, 0.6 to 0.9 part of a cross-linking agent, 0.7 to 2 parts of an assistant cross-linking agent, 0.1 to 0.4 part of a silane coupling agent, 0.1 to 0.25 part of a deacidification agent, 0.25 to 0.5 part of an antioxidant and 0.1 to 0.25 part of an anti-PID reagent. The EVA material is used as the substrate material, the assistant is combined, and the special process control is matched, so that the tensile property of the adhesive film can be improved, the adhesive film is not easy to deform after being rolled and stretched, and the problem that the skin film is difficult to roll is solved; and the problem of non-uniform casting in film production can be effectively solved, and the product quality of the skin film is improved.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaic adhesive films, and in particular to a skin film preparation process based on EVA materials. Background Art

[0002] At present, in the photovoltaic field, several leading component manufacturers are gradually introducing 0BB technology and applying it to solar cells, such as TopCon, HJT, BC, etc. The application of 0BB technology requires a new packaging solution. As one of the key packaging materials, skin membrane came into being, so the skin membrane product is a new concept product for the entire market. Its performance indicators are determined according to its application scenario. As a thin film, the skin membrane covers the surface of the solar cell to fix the 0BB welding ribbon without affecting the lighting efficiency of the solar cell. Therefore, the skin membrane is defined as an ultra-thin photovoltaic adhesive film with good light transmittance and anti-aging properties, as well as low fluidity and fast curing physical and chemical properties.

[0003] At present, many film manufacturers are working on overcoming this difficulty. The skin film is very thin, and there are many difficulties in the production process, specifically: 1. The skin film is thin, and it is easy to have uneven thickness during production, and it is easy to break during the winding process. At the same time, uneven film thickness can easily form cavities during the lamination process; 2. The thin film cannot withstand too much tension during the winding process, and excessive tension can easily cause tensile deformation; 3. The thin film thickness makes the skin film close to a transparent state, so the marks on the film can be clearly seen. If the material is unevenly mixed, it is easy to see the casting marks of the additive particles on the film, resulting in uneven distribution of the additives on the film and affecting the appearance.

[0004] For example, Chinese patent CN116535996A discloses a solar cell encapsulation film, which is a white EVA encapsulation film for single-glass module encapsulation, belonging to the photovoltaic field; the encapsulation film contains EVA matrix resin, high body impedance aging masterbatch, high-performance water barrier, composite white masterbatch, cross-linking agent, auxiliary cross-linking agent, silane coupling agent, light stabilizer. The prepared film has the characteristics of improved anti-PID ability, high water vapor barrier, low free acetic acid formation, high film melting point, etc. The film is prone to stretching deformation during the winding process, affecting the quality of the film product. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a skin membrane preparation process based on EVA material, so as to achieve the purpose of not being easily deformed during winding and stretching, and stable and reliable winding.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] The skin film preparation process based on EVA material comprises the following steps:

[0008] Firstly, EVA is used as the base material, and a cross-linking agent, a co-cross-linking agent, a silane coupling agent, an antioxidant, an acid scavenger, and an anti-PID agent are added;

[0009] The mixed EVA particles are cast and embossed by an extruder, then pulled, flattened and rolled up, and then enter the irradiation equipment for irradiation treatment, rolling and slitting.

[0010] in,

[0011] The particle components and mass fractions of the skin film are as follows: 40-60 parts of high melt index EVA particles, 40-60 parts of low melt index EVA particles, 0.6-0.9 parts of crosslinking agent, 0.7-2 parts of auxiliary crosslinking agent, 0.1-0.4 parts of silane coupling agent, 0.1-0.25 parts of acid scavenger, 0.25-0.5 parts of antioxidant, and 0.1-0.25 parts of anti-PID agent.

[0012] The crosslinking agent is a peroxide crosslinking agent, which is one or more of tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy (2-ethylhexyl) carbonate, 1,1-(diperoxy-tert-butyl) 3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and tert-butyl peroxycarbonate-2-ethylhexyl ester;

[0013] The auxiliary cross-linking agent is one or more of triallyl cyanurate, triallyl isocyanurate, ethoxylated trimethylolpropane triacrylate, 1,2-diallyl phthalate, and trimethylolpropane triacrylate;

[0014] The silane coupling agent is one or more of γ-methacryloxypropyltrimethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyltrimethylsilane, and 3-aminopropyltriethoxysilane;

[0015] The acid scavenger is one or more of magnesium hydroxide, aluminum hydroxide, magnesium oxide, and zinc oxide;

[0016] The antioxidant is one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester, 4-[(4,6-dioctylthio-1,3,5-triazine-2-yl)amino]-2,6-di-tert-butylphenol, propoxylated glycerol triacrylate, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester, tris(2,4-di-tert-butylphenyl) phosphite, (polysuccinic acid (4-hydroxy-2,2,6,6,-tetramethyl-1-piperidinylethanol) ester, and sebacic acid bis-2,2,6,6-tetramethylpiperidinol ester;

[0017] The anti-PID agent is one or more of zirconium phosphate, silicon dioxide, titanium dioxide, chromium oxide, and indium tin oxide.

[0018] The process steps are:

[0019] Pour the base particles and solid additives into a stirring kettle, and use a spray atomizer to stir and mix the liquid additives at a temperature of 50±5°C and a relative humidity of 60±10%RH for 4-6 hours. During the stirring process, a mixing circulation system is used to help the particle additives mix evenly;

[0020] After the particles are mixed, the material is drawn into a single-screw extruder, the barrel temperature is set at 60-80°C, the filter screen link head and other devices are set at 80-90 degrees Celsius, and the die head temperature is set at 95-105°C. The mixed particles are fed through the screw, extruded, cast, embossed with a steel rod and rubber roller, cooled and pulled, flattened and slit, rolled, and irradiated for winding and slitting.

[0021] When the feed speed of the extruder is reduced, the screw rotation speed is reduced to 5-8r / min, and the steel roller adjusts the rotation speed according to the required thickness and gram weight of the film; the film after cast winding enters the irradiation equipment, using a beam current of 35-45mA and a rotation speed of 10-15r / min.

[0022] The extruder is initially fed slowly, and the adjusting nut of the extruder die head is adjusted to the tightest while feeding slowly. After the extrusion is balanced, the tightness of the nut is adjusted slightly to gradually adjust the film thickness to be uniform.

[0023] The liquid additive is added by atomization spraying. The liquid additive is sprayed by atomization equipment and the particles are quickly stirred. After the additive spraying is completed, it is left to stand for more than 5-7 hours.

[0024] After the extruder cast embossing is cooled, a traction roller mechanism is added, and a group of small width winding rollers are used for winding behind the traction rollers.

[0025] The rotation speed of the extrusion screw of the extruder is lowered, and at the same time the closed-loop pressure of the screw feed is opened and the pressure is reduced.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] The skin membrane preparation process based on EVA material is reasonably designed. It uses EVA material as the base material, combines additives, and cooperates with special process control. It can improve the tensile properties of the film, and it is not easy to deform when rolled up and stretched, solving the problem of difficulty in rolling up the skin membrane; it can also effectively solve the problem of uneven film production casting and improve the quality of the skin membrane product. DETAILED DESCRIPTION

[0028] The specific implementation modes of the present invention are further explained in detail below through the description of embodiments.

[0029] The skin film preparation process based on EVA material of the present invention comprises the following steps:

[0030] Firstly, EVA is used as the base material, and a cross-linking agent, a co-cross-linking agent, a silane coupling agent, an antioxidant, an acid scavenger, and an anti-PID agent are added;

[0031] The mixed EVA particles are cast and embossed by the extruder, then pulled, flattened and rolled up, and then enter the irradiation equipment for irradiation treatment, rolling and slitting;

[0032] in,

[0033] The particle composition and mass fraction of the skin film: 40-60 parts of high melt index EVA particles, 40-60 parts of low melt index EVA particles, 0.6-0.9 parts of cross-linking agent, 0.7-2 parts of auxiliary cross-linking agent, 0.1-0.4 parts of silane coupling agent, 0.1-0.25 parts of acid scavenger, 0.25-0.5 parts of antioxidant, and 0.1-0.25 parts of anti-PID agent.

[0034] Preferred:

[0035] The crosslinking agent is a peroxide crosslinking agent, which is one or more of tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy (2-ethylhexyl) carbonate, 1,1-(diperoxy-tert-butyl) 3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and tert-butyl peroxy-2-ethylhexyl carbonate;

[0036] The auxiliary cross-linking agent is one or more of triallyl cyanurate, triallyl isocyanurate, ethoxylated trimethylolpropane triacrylate, 1,2-diallyl phthalate, and trimethylolpropane triacrylate;

[0037] The silane coupling agent is one or more of γ-methacryloxypropyltrimethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyltrimethylsilane, and 3-aminopropyltriethoxysilane;

[0038] The acid scavenger is one or more of magnesium hydroxide, aluminum hydroxide, magnesium oxide, and zinc oxide;

[0039] The antioxidant is one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester, 4-[(4,6-dioctylthio-1,3,5-triazine-2-yl)amino]-2,6-di-tert-butylphenol, propoxylated glycerol triacrylate, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester, tris(2,4-di-tert-butylphenyl) phosphite, (polysuccinic acid (4-hydroxy-2,2,6,6,-tetramethyl-1-piperidinylethanol) ester, and sebacic acid bis-2,2,6,6-tetramethylpiperidinol ester;

[0040] The anti-PID agent is one or more of zirconium phosphate, silicon dioxide, titanium dioxide, chromium oxide, and indium tin oxide.

[0041] After the above raw and auxiliary materials are prepared, the following process steps are implemented:

[0042] Pour the base particles and solid additives into a stirring kettle, and use a spray atomizer to stir and mix the liquid additives at a temperature of 50±5°C and a relative humidity of 60±10%RH for 4-6 hours. During the stirring process, a mixing circulation system is used to help the particle additives mix evenly;

[0043] After the particles are mixed, the material is drawn into a single-screw extruder, the barrel temperature is set at 60-80°C, the filter screen link head and other devices are set at 80-90 degrees Celsius, and the die head temperature is set at 95-105°C. The mixed particles are fed through the screw, extruded, cast, embossed with a steel rod and rubber roller, cooled and pulled, flattened and slit, rolled, and irradiated for winding and slitting.

[0044] in,

[0045] When the feed speed of the extruder is reduced, the screw rotation speed is reduced to 5-8r / min, and the steel roller adjusts the speed according to the required thickness and gram weight of the film; the film after cast winding enters the irradiation equipment, using a beam current of 35-45mA and a speed of 10-15r / min.

[0046] Further:

[0047] To solve the problem of uneven thickness of the film production, the present invention adopts the following process control: 1. lowering the rotation speed of the extrusion screw of the extruder, and at the same time opening the closed-loop pressure of the screw feed and reducing the pressure; 2. adjusting the adjusting nut of the extruder die head to the tightest while slowly feeding, and adjusting the tightness of the nut slightly after the extrusion is balanced, and gradually adjusting to a uniform film thickness.

[0048] To avoid excessive pressure on the skin membrane, the present invention adopts the following process control: 1. After the extruder cast embossing is cooled, a traction roller is added; 2. A plurality of small width winding rollers are used for winding after the traction roller.

[0049] The material mixing is uneven, and the problem reflected on the skin film is very obvious, so it is necessary to add additives during the stirring process. The liquid additives are sprayed using atomization equipment, and the particles are quickly stirred. At the same time, the appropriate temperature is selected to help the particles quickly absorb the additives. After the additives are sprayed, they still need to be left to stand for more than 6 hours before the stirring is completed.

[0050] The present embodiment is specifically as follows:

[0051] Example 1: 60 parts of EVA high melt index particles, 40 parts of low melt index particles, 0.8 parts of tert-butyl peroxycarbonate-2-ethylhexyl ester, 0.6 parts of triallyl isocyanurate, 1 part of trimethylolpropane triacrylate, 0.35 parts of γ-methacryloxypropyltrimethoxysilane, 0.1 parts of magnesium hydroxide, and 0.15 parts of zirconium phosphate; the above raw materials are added into a stirring kettle, processed according to the above process steps, and rolled up to obtain a film product weighing about 100 g.

[0052] Example 2: 60 parts of EVA high melt index particles, 40 parts of low melt index particles, 0.6 parts of tert-butyl peroxycarbonate-2-ethylhexyl ester, 0.2 parts of tert-amyl peroxy (2-ethylhexyl) carbonate, 0.7 parts of triallyl isocyanurate, 1 part of trimethylolpropane triacrylate, 0.35 parts of γ-methacryloxypropyl trimethoxysilane, 0.1 parts of magnesium hydroxide, and 0.15 parts of zirconium phosphate; the above raw materials are added to a stirred tank, processed according to the above process steps, and rolled to obtain 100g / m 2 Film products with a weight of about 500 grams.

[0053] Example 3: 60 parts of EVA high melt index particles, 40 parts of low melt index particles, 0.75 parts of tert-butyl peroxycarbonate-2-ethylhexyl ester, 0.7 parts of triallyl isocyanurate, 1.2 parts of trimethylolpropane triacrylate, 0.4 parts of γ-methacryloxypropyltrimethoxysilane, 0.15 parts of magnesium hydroxide, and 0.15 parts of zirconium phosphate; the above raw materials are added to a stirred tank, processed according to the above process steps, and rolled to obtain 100g / m 2 Film products with a weight of about 500 grams.

[0054] The film products obtained by winding the above three embodiments were treated by irradiation equipment, with an irradiation line speed of 10r / min and a beam current of 38mA. The test data of the treated film products are as follows:

[0055]

[0056] The skin membrane preparation process based on EVA material of the present invention is reasonably designed. It takes EVA material as the base material, combines additives, and cooperates with special process control. It can improve the tensile performance of the film, and it is not easy to deform when rolled up and stretched, thereby solving the problem of difficulty in rolling up the skin membrane; it can also effectively solve the problem of uneven film production casting, thereby improving the quality of the skin membrane product.

[0057] The above is an exemplary description of the present invention. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A skin film preparation process based on EVA material, characterized in that: The film preparation process comprises the following steps: Firstly, EVA is used as the base material, and a cross-linking agent, a co-cross-linking agent, a silane coupling agent, an antioxidant, an acid scavenger, and an anti-PID agent are added; The mixed EVA particles are cast and embossed by an extruder, then pulled, flattened and rolled up, and then enter the irradiation equipment for irradiation treatment, rolling and slitting.

2. The skin film preparation process based on EVA material as claimed in claim 1, characterized in that: The particle components and mass fractions of the skin film are as follows: 40-60 parts of high melt index EVA particles, 40-60 parts of low melt index EVA particles, 0.6-0.9 parts of crosslinking agent, 0.7-2 parts of auxiliary crosslinking agent, 0.1-0.4 parts of silane coupling agent, 0.1-0.25 parts of acid scavenger, 0.25-0.5 parts of antioxidant, and 0.1-0.25 parts of anti-PID agent.

3. The skin film preparation process based on EVA material as claimed in claim 2, characterized in that: The crosslinking agent is a peroxide crosslinking agent, which is one or more of tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy (2-ethylhexyl) carbonate, 1,1-(diperoxy-tert-butyl) 3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and tert-butyl peroxycarbonate-2-ethylhexyl ester; The auxiliary cross-linking agent is one or more of triallyl cyanurate, triallyl isocyanurate, ethoxylated trimethylolpropane triacrylate, 1,2-diallyl phthalate, and trimethylolpropane triacrylate; The silane coupling agent is one or more of γ-methacryloxypropyltrimethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyltrimethylsilane, and 3-aminopropyltriethoxysilane; The acid scavenger is one or more of magnesium hydroxide, aluminum hydroxide, magnesium oxide, and zinc oxide; The antioxidant is one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester, 4-[(4,6-dioctylthio-1,3,5-triazine-2-yl)amino]-2,6-di-tert-butylphenol, propoxylated glycerol triacrylate, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester, tris(2,4-di-tert-butylphenyl) phosphite, (polysuccinic acid (4-hydroxy-2,2,6,6,-tetramethyl-1-piperidinylethanol) ester, and sebacic acid bis-2,2,6,6-tetramethylpiperidinol ester; The anti-PID agent is one or more of zirconium phosphate, silicon dioxide, titanium dioxide, chromium oxide, and indium tin oxide.

4. The skin film preparation process based on EVA material as claimed in claim 2, characterized in that: The process steps are: Pour the base particles and solid additives into a stirring kettle, and use a spray atomizer to stir and mix the liquid additives at a temperature of 50±5°C and a relative humidity of 60±10%RH for 4-6 hours. During the stirring process, a mixing circulation system is used to help the particle additives mix evenly; After the particles are mixed, the material is drawn into a single-screw extruder, the barrel temperature is set at 60-80°C, the filter screen link head and other devices are set at 80-90 degrees Celsius, and the die head temperature is set at 95-105°C. The mixed particles are fed through the screw, extruded, cast, embossed with a steel rod and rubber roller, cooled and pulled, flattened and slit, rolled, and irradiated for winding and slitting.

5. The skin film preparation process based on EVA material as claimed in claim 4, characterized in that: When the feed speed of the extruder is reduced, the screw rotation speed is reduced to 5-8r / min, and the steel roller adjusts the rotation speed according to the required thickness and gram weight of the film; the film after cast winding enters the irradiation equipment, using a beam current of 35-45mA and a rotation speed of 10-15r / min.

6. The skin film preparation process based on EVA material as claimed in claim 4, characterized in that: The extruder is initially fed slowly, and the adjusting nut of the extruder die head is adjusted to the tightest while feeding slowly. After the extrusion is balanced, the tightness of the nut is adjusted slightly to gradually adjust the film thickness to be uniform.

7. The skin film preparation process based on EVA material as claimed in claim 4, characterized in that: The liquid additive is added by atomization spraying. The liquid additive is sprayed by atomization equipment and the particles are quickly stirred. After the additive spraying is completed, it is left to stand for more than 5-7 hours.

8. The skin film preparation process based on EVA material as claimed in claim 4, characterized in that: After the extruder cast embossing is cooled, a traction roller mechanism is added, and a group of small width winding rollers are used for winding behind the traction rollers.

9. The skin film preparation process based on EVA material as claimed in claim 5, characterized in that: The rotation speed of the extrusion screw of the extruder is lowered, and at the same time the closed-loop pressure of the screw feed is opened and the pressure is reduced.

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