JPS5922978A - Caulking adhesive sheet and its manufacture - Google Patents

Abstract

PURPOSE:To provide the titled sheet having high antistaticity and excellent blocking resistance, and applicable by means of inexpensive vacuum heating process, by forming a molding material containing an ethylene copolymer and an organic peroxide in the form of sheet, and embossing both faces of the sheet. CONSTITUTION:A molding material containing an ethylene copolymer (preferably ethylene-vinyl acetate copolymer), an ethylene copolymer and a coupling agent or a silane-modified ethylene copolymer, and an organic peroxide (e.g. t-butyl peroxyisopropyl carbonate), is extruded with a T-die extruder in the form of molten web at a temperature below the decomposition point of the organic peroxide. The web is pressed by passing, together with embossed release paper, through the gap between a cooling roll having embossing pattern and a press rubber roll, and cooled and solidified to obtain the titled sheet having embossed patterns at both surfaces preferably to a depth of >=0.03mm.. USE:For the module of solar cell.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to filled adhesive sheets and methods of manufacturing the same. More particularly, the present invention relates to a filled adhesive sheet exhibiting improved adhesion that is effectively used in solar cell modules and a method for manufacturing the same.

In recent years, it has been pointed out that existing energy sources, mainly oil, have been depleted, and there has been a need to develop alternative energy sources.In this context, solar power generation has been recognized as a clean energy source and as a source of inexhaustible solar radiant energy. There is a desire for its immediate practical application and widespread use.

The first method is to use solar cells to directly convert the sun's radiant energy into electrical energy, and this function can be obtained by utilizing the ferrule effect of semiconductors, generally silicon semiconductors, selenium semiconductors, etc. .

By the way, the functionality of silicon semiconductors deteriorates when directly exposed to the outside air, so for the purpose of protection from the outside air, upper transparent protective materials made of glass, acrylic resin, carbonate resin, etc., Oyohi Glass, stainless steel, aluminum, etc. are used. It is protected by a lower board protection material made of plastic or the like. At this time, the high-performance silicon semiconductors used for solar power generation are usually wafers (small thin film pieces), so these wafers are arranged in series or parallel using interconnectors, electrically connected,
There is a need for immobilization, and filling adhesives are commonly used because of this need.

The physical properties required of this filling adhesive include the following.

(2) In order to prevent wafers such as silicon semiconductors from being destroyed by internal strain caused by thermal expansion and contraction, they must have elastomeric properties. Since power generation is possible only after successive induction with the silicon semiconductor, the filler adhesive used during this process must have high sunlight transmittance.(3) Adhesion to the external protective material (4) Webs such as silicon semiconductors have a small electromotive force, so a useful voltage can be obtained by connecting the webs in parallel across the itf rows, so the connecting material should not be corroded. (5) There should be no change in each of the above properties after being left outdoors for a long period of time. Conventionally, heat-crosslinking liquid silicone resins have been used as having these properties. However, this method has drawbacks such as being expensive, requiring long coating and bonding steps, and being unsuitable for automation. For this reason, sheets of polyvinyl butyral resin, which has a proven track record in laminated glass, have recently begun to be used, but this is not necessarily satisfactory as a filler adhesive for solar cells. That is, the polyvinyl butyral sheet has starch and sodium bicarbonate attached to its surface to prevent blocking.
Prior to use, it must be washed with water, dried, and conditioned. Furthermore, since the fluidity of the resin is poor, it is necessary to use an autoclave for bonding, which takes a long time and is not suitable for automation. Furthermore, in terms of quality,
Due to its high water absorption rate, it has poor humidity characteristics, and if left in high humidity for a long time, it will cause devitrification, which will not only reduce the light transmittance but also significantly reduce the adhesive strength. A peeling phenomenon occurs at the interface between the lower substrate protective material and the solar cell element. Furthermore, low-temperature properties (flexibility) are not necessarily good.

In place of such polyvinyl butyral sheets with a melting point of between 1 and 2, ethylene-vinyl acetate copolymer C-1 has recently begun to be studied from the perspective of reducing the cost of solar cell modules. However, the commonly used ethylene-vinegar 1(-vinyl copolymer) cannot satisfy the characteristics required as a filling adhesive for solar cells. As the vice increases,
Although transparency and flexibility are improved, sheet formability and anti-blocking properties are deteriorated, making it difficult to satisfy both properties at the same time, and heat resistance and light resistance are also insufficient. Furthermore, the durable adhesion with the upper transparent excitation material and the lower substrate protection material, which determine the reliability of the solar cell module, is not sufficient.

Furthermore, in view of the shape of the filled adhesive sheet, there are cases where the embossed pattern is applied only on one side or both sides.
! :11, there are disadvantages such as a decrease in workability due to insufficient anti-blocking properties and unavoidable troubles due to charging properties. Unfortunately, with these sheets, sufficient degassing is not carried out during through-air heating lamination to create solar cell modules, making it impossible to avoid the problem of bubble formation. In order to avoid the formation of bubbles, it is necessary to insert a spacer such as glass fiber between the base material and the sheet, which not only complicates the bonding process but also causes uneven optical properties. There were some drawbacks, such as being able to only perform matching.

For these reasons, it was thought that a sheet with embossed patterns on both sides would be suitable, but according to the inventors' study,
The following problems were observed in its production and excretion.

Sheets used in solar cell modules generally have a thickness of 0.
The sheet has a thickness of approximately 2 to 1 mm thick, and such sheets are formed using a φ-die sheet forming machine or an inflation sheet forming machine, but the latter method is disadvantageous in terms of inner surface blocking. It was appropriate.

T-die sheet forming machines usually use a two- or three-roll take-off line, and in either case, the molten web extruded from the firefly die is pressed between the two rolls, cooled, and solidified. It will be done. If the rolls used at this time are all metal rolls with embossed patterns, the minimum thickness of the sheet that can be practically formed is 0.8~
If the thickness is less than this, the clearance between the metal rolls will be small, making it difficult to make one adjustment, and there will be problems such as the risk of damage to the rolls due to contact between two metal rolls. arise.

For this reason, when embossing sheets with a thickness of 1 m or less, a rubber roll is usually used as one of the rolls.
In the sheets manufactured on this line, the embossment on the transfer surface of the rubber roll was insufficient, so the formation of the bubbles described above was unavoidable. Unfortunately, the transfer surface of the rubber roll is highly charged, which tends to cause build-up, and when unwinding sheets stacked in rolls or sheets or taking them out one by one, blocking is required. A decline in sexuality was inevitable.

Another option is to form the sheet into a sheet and then emboss both sides of the sheet using an embossing machine, but the method described above also applies when the rolls used are two metal rolls or one of them is a rubber roll. The same drawbacks cannot be avoided.

The present inventors have conducted various studies to solve the above-mentioned defects in terms of the molding material observed in ethylene-based copolymer sheets and the above-mentioned disadvantages in the molding process observed when embossing the sheets. It has been found that a filled adhesive sheet molded from a molding material containing a polymer and an organic peroxide and which is embossed on both sides effectively achieves the desired object.

That is, such a filled adhesive sheet does not require washing, drying, and dispensing equipment as seen in polyvinyl butyral sheets, nor does it require expensive equipment such as an autoclave, and can be laminated using inexpensive vacuum heating equipment. is possible, does not require materials for degassing such as glass cloth spacers, is less expensive compared to liquid silicone resin or polyvinyl butyral resin, and is suitable for the bonding process for solar cell module fabrication. In addition to achieving automation, shortening, and cost reduction, the embossability of the sheet performed by the forming method described below is also good, and the sheet with the embossed pattern is free from foreign matter caused by electrostatic charge on the sheet. It also has the effect of preventing contamination and eliminating blocking troubles.

The filled adhesive sheet preferably has a depth of 0 on both sides.
It has an embossed pattern of Q3mm or more and is manufactured by the following method.

(1) A tri-blended molded 4J material containing an ethylene copolymer and a peroxide is melted from a T-die extruder at a temperature that does not substantially decompose the organic peroxide. A method of forming a sheet with an embossed pattern on the screen by extruding it as a web and pressing it together with an embossed release paper between a cooling roll with an embossed pattern and a pressure bonding rubber roll, cooling and solidifying it (2) A tri-blended molding material containing an ethylene-based copolymer and an organic peroxide is extruded as a molten web through a T-die extruder at a temperature at which the organic peroxide does not substantially decompose to form an embossed pattern. After passing between the engraved cooling roll and the pressure-bonding rubber roll, and once cooling and solidifying to form a single-sided embossed sheet, release paper is placed on the non-embossed side of the single-sided embossed sheet, and the release paper and The surfaces of the web that are not in contact with each other are heated again to a temperature at which the organic peroxide does not substantially decompose, the release paper laminated web is passed between the roll and the pressure bonding rubber roll, and is then cooled and solidified to form an embossed pattern on both sides. The ethylene copolymer used in the present invention has a light transmittance of about 80% or more, preferably about 90% or more, and an elastic modulus of about 1-30 MPa, preferably about 3-30 MPa. 12 MPa is used as a suitable copolymer.Specifically, for example, a copolymer of ethylene and a vinyl ester such as vinyl acetate or vinyl propionate,
Copolymers of ethylene and unsaturated fatty acid esters such as ethyl acrylate, butyl acrylate, and methyl methacrylate; copolymers of ethylene and α-olefins such as propylene and butene-1,4-methylpentene-1; For example, ethylene-vinyl ester-unsaturated fatty acid ternary copolymer, ethylene-unsaturated fatty acid ester-unsaturated fatty acid ternary copolymer, or metal salts thereof (ionomer resin) are used.

Among these ethylene-based copolymers, the most preferred one from an economic point of view is an ethylene-vinyl acetate copolymer, in which case both 1 (including vinyl acetate in the copolymer, 1 is about 20 -40% by weight (6%, preferably about 25-40% by weight).If the vinyl acetate content is less than this,
The light transmission chamber becomes low, the power generation efficiency of the module becomes low, and the elastic modulus becomes high, causing the power generation element to deteriorate.
II! Due to g tension contraction, the risk of breakage increases. However, in the case where a filling adhesive sheet is pasted under the solar cell element which has been annealed on the lower surface of the upper transparent protection side, the light transmittance of that part is irrelevant, so the vinyl acetate content is Up to about 20% by weight of ethylene-vinyl acetate copolymer may also be used. On the other hand, if the vinyl acetate content increases more than this, the extrusion moldability of the sheet will deteriorate, and the resulting sheet will become more sticky and prone to blocking.

The organic peroxide contained in such an ethylene copolymer can be mixed with a light stabilizer added as necessary to form a sheet using an extruder, and the molding temperature and the length of time maintained at this temperature. A material is used that does not substantially decompose in the process, but quickly decomposes at a temperature below the decomposition temperature of the ethylene copolymer during the modularization process. - for the crotch, about 90-190°C, preferably about 120-160°C;
Those having a decomposition temperature (temperature at which the half-life is 1 hour) of °C are used.

Examples of such organic peroxides include tert-butyl peroxyisopropyl carbonate, tert-butyl peroxy acetate, tert-butyl peroxybenzoate, dicumyl peroxide, 2,5-dimethyl-2,5-bis( 3-butylperoxy)hexane, di-tert-butylperoxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane-3,1,1-bis(tert-butylperoxy) -3,3,5 -) Limethylcyclohexane, i,i-bis(tert-butylperoxy)cyclohexane, methyl ethyl ketone peroxide, 2,5
-dimethylhexyl-2,5-bisperoxybenzoate, tert-butyl hydroperoxide, p-menthane hydroperoxide, benzoyl peroxide, p-chlorobenzoyl peroxide, tert-butyl peroxyisobutyrate, hydroxy Examples include butyl peroxide and chlorhexanone peroxide.

These organic peroxides are added in the amount necessary to cause the ethylene copolymer to crosslink during heating during the solar cell module bonding process, improve heat resistance, and contribute to improved adhesion. be done. Generally, ethylene copolymer 10
About 0.1 to 5 parts by weight, preferably about 0.0 parts by weight.
5 to 3 parts by weight of organic peroxide are added. If the addition ratio is less than this, the transparency, heat resistance and adhesion will be insufficient.0 If stricter light resistance is required for the filled adhesive, a light stabilizer may be added. Preferably, for example 2-hydroxy-4-methoxybenzophenone, 2
．． 2'-dihydroxy-4-methoxybenzophenone,
Benzophenone series such as 2-hydroxy-4-methoxy-2'-carboxybenzophenone and 2-hydroxy-4n-octoxybenzophenone, 2-(2'-hydroxy-3', 5'-di-tert-butylphenyl)benzotriazole , 2-(2'-hydroxy-5-methylphenyl)benzotriazole, 2-(2'-hydroxy-5-tertiary octylphenyl)benzotriazole, phenyl salicylate, p-
Salicylic acid esters such as octylphenylated salicylate, nickel complex salts, hindered amines, and the like are used as light stabilizers.

These light stabilizers also include hindered phenolics,
A synergistic effect may be expected when used in combination with antioxidants such as phosphites.

A sheet molded from a molding material containing an ethylene copolymer and a peroxide as described above, and having an embossed pattern on both sides of the sheet by a specific method described below, is then molded as needed. A brimer treatment is performed on the surface. For brimer treatment, embossed sheet is coated with coupling agent solution 411! This is generally done by passing the coupling agent through the sheet and forming a layer of coupling agent on the surface of the sheet.

As a coupling agent, the general formula R31Xs (where R is a reactive organic group such as a vinyl group, an aminoalkyl group, a methacryloxyalkyl group, an acryloxyalkyl group, a mercaptoalkyl group, or an epoxy group, and X is a halogen an organic silane compound having the general formula R-□5i (001'r/), which is a hydrolyzable group such as an atom, an alkoxy group, or an acetoxy group.

(Here, R' is a vinyl group or an alkyl group, and R
is a hydrocarbon group, n is an integer of 1 to 4) or an organic silane peroxide represented by the general formula R'l10T1
(0YHIILz), (where R/I/ is an alkyl group, Y is a carboxyl group, a phosphate group,
is a pyrophosphate group, a phosphite group, or a sulfonyl group, and 2 is a hydrogen atom, an amine group, a hydroxyl group,
mercapto, acrylic or methacrylic)
Typical examples include organic titanate compounds shown in the following.

For these coupling agents, in addition to the naturally required good adhesive function, consideration must be given to factors such as kneading and compatibility with the ethylene copolymer, odor, light resistance, non-corrosion to interconnectors, etc., and cost. you need to pay. From this point of view, preferred coupling agents include vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, r-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, r-glycidoxypropyltrimethoxysilane, and r-glycidoxypropyltrimethoxysilane. It is an organic silane compound having an unsaturated group or an epoxy group, such as -glycidoxypropyltriethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

When using an organosilane peroxide as a coupling agent, it is suitable that its decomposition temperature (temperature at which the half-life is 1 hour) is about 90 to 190°C, preferably about 120 to 160°C. . C! H3Si(00t-Bu), 0H2=aHs
Examples include 1 (OOR) (where R is a tertiary butyl group, a cumyl group, or a p-menthyl group).

Brimers containing these coupling agents can be prepared as a solution of aliphatic hydrocarbons, aromatic hydrocarbons, chlorinated hydrocarbons, alcohols, ketones, organic solvents such as esters, water or a mixed solvent of water and a water-soluble organic solvent. used. The concentration of the coupling agent in the primer is suitably about 0.1 to 10%, preferably about 0.5 to 5%, from the viewpoint of adhesive performance and economical efficiency.

It is also possible to use a filled adhesive sheet without brimer treatment, and in this case, it is desirable to apply brimer treatment to the mating material to which the filled adhesive sheet is to be bonded.

Instead of brimer treatment with such a coupling agent,
It is also possible to incorporate the same coupling agent itself into a molding material together with an ethylene copolymer and an organic peroxide, and to mold a filled adhesive sheet from the molding material. In this case, the coupling agent is ethylene copolymer 10
From the viewpoint of economy and adhesion, it is generally used in an amount of about 0.1 to 10 parts by weight, preferably about 0.5 to 5 parts by weight. The combination of this and an organic peroxide provides stronger adhesion that is useful in practice. That is, compared to the case where only the coupling agent or organic peroxide is used, the adhesiveness is clearly improved when these are used in combination.

The cause of this is not fully understood, but for example, when a silane curving agent with an unsaturated group is used, the organic peroxide decomposes during heating and bonding, generating radicals in the ethylene copolymer. The majority of these polymer radicals appear to be involved in the crosslinking reaction of the ethylene copolymer resin, but the remaining part reacts with the unsaturated groups of the silane coupling agent, which means that the coupling agent reacts with the ethylene copolymer resin. It is believed that this grafted coupling agent is involved in forming stronger adhesion.

From this point of view, instead of using an ethylene copolymer and a camping agent together with a silane camping agent, a molding material using a silane-modified ethylene copolymer together with an organic peroxide has been considered, and in fact, such molding Sheets molded from the material exhibit even better adhesion. In addition,
In this case, if various organometallic compounds such as dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctoate, etc. are used in conjunction with the organic peroxide, water resistance etc. can be further improved. be done.

Silane modification of ethylene-based copolymers involves heating a silane compound, as indicated above as a coupling agent, to a humidity generally above about 140° C., preferably in the presence of a free radical-generating compound such as an organic peroxide. It is carried out by reacting.

During this reaction, a portion of the silane modifier may remain unreacted, but this unreacted compound becomes a source of odor when the silane-modified ethylene copolymer is formed into a sheet. , there is no problem in terms of quality. If necessary, this unreacted compound can be removed in advance by a well-known technique using a vented extruder or the like. Although the content of silane groups in the modified resin is not particularly limited,
From the viewpoints of crosslinking reactivity, adhesiveness, economic efficiency, etc., the amount is generally in the range of about 0.1 to 10% by weight, preferably about 0.3 to 3% by weight. The modified resin can also be used as a blend of a silane-modified ethylene copolymer and an unmodified ethylene copolymer, and in this case, the range of the silane group content relative to the total polymerization of both Commonly used.

The unmodified ethylene copolymer used preferably has a chemical structure that is the same as or close to that of the silane-modified ethylene copolymer blended with it before silane modification, and generally has a lower vinyl acetate content. is about 2
Ethylene-vinyl acetate copolymer of 0 to 40% by weight is used. Further, it is preferable to use these ethylene copolymers (referring to silane-modified and unmodified ethylene copolymers) having the same melt fluidity. This is because these similarities in chemical structure and melt flowability affect melt-kneading properties during sheet molding, as well as optical properties and adhesive properties after lamination. Generally, about 5 parts by weight of unmodified ethylene copolymer per 100 parts by weight of silane-modified ethylene copolymer.
C is used by blending it in a proportion of 00 parts by weight or less.

Embossed sheets made from molding materials using ethylene copolymers, ethylene copolymers and coupling agents, or silane-modified ethylene copolymers (hereinafter collectively referred to as ethylene copolymer resins) in combination with organic peroxides. Molding is carried out according to methods (1) and (2) above, specifically as follows. First, an ethylene copolymer resin, an organic peroxide, and if necessary a light stabilizer are added. The mixture is triblended in advance using a known mixing device, such as a pump blender or tumbler mixer, and then fed from the hopper of an extruder. The extruder may be any device as long as it has the function of melt-kneading the triblend at a temperature at which the organic peroxide does not substantially decompose.
A commonly used single-screw extruder for polyethylene molding may be used. The resin melt-kneaded in the extruder is introduced into a T-die heated to a temperature at which the organic peroxide does not substantially decompose, and extruded as a molten web.

The T-die used here can be any type that has the function of extruding the molten resin into a sheet in a molten state.
An ordinary straight manifold type T-die for polyethylene molding can be used.

The molten web extruded from the T-die is
It is formed into an embossed sheet by the method shown in the figure.

In the forming method shown in FIG. 1, a molten web 2 extruded from a T-die 1 is rolled together with an embossed release paper 4 unwound from a take-up roll 3 and a cooling roll having an embossed pattern engraved thereon. The double-sided embossed sheet is then passed through a secondary cooling roll 7 to be cooled and solidified, and passed through a guide 8 and peeling rolls 9 and 9', and then transferred to a take-up roll 1o. A series of operations are performed in which the stamp paper is wound up on the take-up roll 11, respectively.

In the forming method shown in FIG. 2, a molten web 2 extruded from a T-die 1 is passed between a cooling roll 5 with an embossed pattern and a pressure rubber roll 6 to be crimped, and then a secondary After passing through the cooling roll 7 and once cooling and solidifying to emboss one side, the embossed release paper 4 unwound from the take-up roll 3 is placed on the non-embossed side of the one-sided embossed sheet 13. , 13', and the surface of the web not in contact with the release paper is heated again using an infrared heater 15 to a temperature at which the organic peroxide does not substantially decompose, and this release paper laminated web is rolled, as necessary. The embossed pattern is passed between the roll 5' and the pressure-bonding rubber roll 6', and the rubber roll 6' is passed through the secondary cooling roll 7' between the guides 15 and 16 to cool and solidify.
9', the double-sided embossed sheet is transferred to a take-up roll 10,
Further, a series of in-line operations are performed in which the release paper is rolled onto the winding roll 11.

Note that the release paper can be peeled off from the double-sided embossed sheet immediately before use, but if the release paper is wound up on a take-up roll as in the embodiment shown in Figures 1 and 2,
Since it can be reused, it is advantageous in terms of cost.

The 41 m embossing provided on both sides of the sheet is suitable for fine patterns such as stripes, cloth grain, satin finish, leather pattern, diamond lattice, and synthetic leather-like wrinkle patterns, and is suitable for purposes such as degassing during vacuum heating bonding. Large patterns such as floral or geometric patterns are not preferred. Regarding the size of the pattern, it is preferable that the shortest distance from the center of gravity of the part with a large area to the part with a small area among the convex parts or four parts of the embossed pattern is short, and this distance is usually 1
It is 0- or less, preferably 2wn or less. In addition, the depth of the groove of the embossed pattern or the clearance between the convex part and the four parts is usually 0.038 or more, preferably 0.038 or more, with respect to the thickness of the sheet, which is generally set to 0.1 to 11rrrn from the viewpoint of cost. Q, l nun or more. Note that the properties of the Enphos 44 on both sides of the sheet may be the same or different.

As mentioned above, the formation of such an embossed pattern is performed by pressing one side of the sheet with an emboss roll or a cooling roll with an embossed pattern engraved on it, and pressing the other side with a peelable paper with an embossed pattern. be exposed. As the embossed release material MI4, so-called processing paper used for synthetic leathers such as polyurethane and polyvinyl chloride is preferably used in view of its good release properties. Peeling paper used for adhesive labels and the like is not very preferable because when it is laminated with a sheet, the peeling resistance is too low and it tends to cause trouble in the receiving line.

Process paper that is preferably used as a release paper can be roughly divided into silicon-coated types and non-coated types, and the former is preferred in the present invention. In other words, the silicon coating type is
It is generally composed of paper/polyethylene/silicon resin and has suitable peel resistance. For the non-coated type, the peeled 11ff side is polypropylene, poly (4
-Methylbenzone-1), etc., and the peeling resistance is too high, so it is not very preferable.

Embossing of process paper is performed using process paper that is easy to be embossed (for example, Soken Seko product FliV 130 TA-7R).
4,]1jV130TA 7R10f,r)ヲx'
＞E7゜It is generally done by a method of processing using a machine, but instead of processing paper that has already been laminated, an embossed pattern is applied at the stage of making 8m paper.
So-called crepe paper may be used, and polyethylene and silicone resin may be laminated thereon.

The method for producing the sheet of the present invention using these embossed rolls or cooling rolls with embossed patterns and embossed release paper through the steps described above can be carried out using inexpensive equipment and inexpensive auxiliary resources. Thickness is 0.1~1
Not only is it possible to apply an embossed pattern with a depth of Q, Q 3 + 1 m1 or more on both sides of a thin sheet called pan, but there is no risk of damage to the embossing roll, and the embossed pattern can be applied on both sides. As a result, it is possible to avoid contamination of foreign matter due to electrostatic charge and a decrease in efficiency during lamination work due to blockage of the sheets.In addition, it is possible to avoid auxiliary materials for deaeration during lamination described below. It has many excellent effects such as being able to obtain a bonded product with excellent optical properties without the need for

Modularization of solar cells using the filled adhesive sheet according to the present invention can be carried out as follows.

When solar cell elements are made of silicon semiconductor or selenium semiconductor wafers, these solar cell elements are made of at least two
The upper transparent protective material is sandwiched between two filled adhesive sheets, and if necessary, the protective material is cleaned with a surfactant solution or organic solvent, or the surface is treated with corona discharge or chemicals. This is done by heat-bonding and bonding under vacuum in a state where the lower substrate protection material is overlapped. At this time, it is industrially preferable to stack or arrange the lower substrate protective material, the filling adhesive sheet, the thick battery element, the filling adhesive sheet, and the upper transparent protective material in order to bond the module. The thick battery element may be laminated in advance with at least two filled adhesive sheets made of an ethylene copolymer containing an organic peroxide, and bonded to the upper transparent protective material and the lower substrate protective material.

It is desirable that the heating progress to a point where the organic peroxide added to the filled adhesive sheet is completely decomposed. Through this heat treatment, the filling adhesive and the outsider protection material are firmly bonded, the solar cell element is laminated with the two filling adhesive sheets, and it is bonded to the upper transparent protection material and the lower substrate protection material. A solar cell module is formed therein which is firmly bonded to the solar cell module.

In addition, when the solar cell element is formed on a protective material such as glass, plastic, ceramic, or stainless steel, a filling adhesive sheet is used as an intermediate layer, and the inward facing surface of one of the protective materials (filling adhesive sheet The upper Y Hideaki protective material and the lower substrate protective material on which solar cell elements are formed (contact surface) are stacked on top and bottom of the intermediate layer filling adhesive sheet, specifically, the lower substrate protective material; A filling adhesive sheet and an upper transparent protective material are stacked on top of the formed solar cell element, or a filling adhesive sheet and a lower substrate protecting material are stacked 11114 times under the solar cell element formed on the lower surface of the upper transparent protecting material. When this was sewn and heat-bonded under vacuum in the same manner as in the previous case, the protective material on one side, the filling adhesive sheet, and the protective material on the other side, on which the solar cell element was formed, were firmly bonded together. A solar cell module is formed therein.

In this way, the solar cell formed by adhering by the method using the filling adhesive sheet according to the present invention has a high peel strength between the protective material and the filling adhesive, and has excellent peeling resistance under humid conditions. It fully satisfies all of the characteristics required for solar cell modules, such as good initial adhesion and durable adhesion, shows little change when exposed to ultraviolet irradiation, and has good light transmittance. In addition, since the filling adhesive sheet is embossed, it prevents sheet blocking and thick
It is particularly effective for degassing during the battery modularization process.

The presence of air bubbles not only deteriorates the appearance but also reduces adhesiveness and heat resistance. In other words, in this filled adhesive sheet, the decomposition of organic peroxide by heating has a strong correlation between adhesiveness and heat resistance, and the presence of air bubbles significantly reduces heat conduction in those areas. The presence of air bubbles must be avoided at all costs, as this will reduce the amount of water and eventually inhibit the decomposition of the organic peroxide.

However, the filled adhesive sheet according to the present invention produces bubbles and is as described above, so it is possible to easily and continuously obtain various bonded products of good quality by using a vacuum heating method. Compared to conventional bonding using polyvinyl butyral sheets, not only is the filled adhesive sheet itself inexpensive, but it also does not require equipment such as cleaning, drying, or humidity conditioning, or an autoclave. The cost is also low in terms of equipment.

Next, the present invention will be explained with reference to examples.

Example 1 Ethylene-vinyl acetate copolymer (Mitsui Polychemical product Evaflex+250, vinyl acetate content 28% by weight,
melt index 159/10 minutes) 100 parts (weight,
(same below), tertiary butyl peroxybenzoate 1.4
part, 0.25 part of 2-hydroxy-4-n-octylbenzophenone and tetrakis-[methylene-3-(3'
, 5'-di-tert-butyl-4'-hydroxyphenyl)
20.1 parts of propionate cometa was triblended using one tumbler mixer.

This tri-blend product was molded using a T-die extrusion molding machine (manufactured by Modern Machinery Co., Ltd., single shaft, diameter 65 +u+, Ho'J
x Full flight metering type screw for tyrene, straight manifold type Chigui) - to extrude a sheet-like molten web. The resin temperature at the die exit was 95°C, and the set temperatures of the extruder and T-die were 110°C or lower. 1, the rotation speed of the screw was 30 rpm.

The molten web extruded from the T-die is
Embossing was carried out according to the steps shown in the figure. As the embossed release paper, an embossed process paper (Souken Sekisho EV 130 TA, 7 R4, silicone coated type) is used, and this process paper is embossed with a fine ripple pattern. Further, the pattern engraved on the cooling roll is a diamond lattice, the lattice spacing of which is 0.5M, and the depth is 0.2 ml. The rubber coated on the pressure-bonding rubber roll is made of silicone rubber with a shore hardness of A of 65, and its surface is polished. The sheet and release paper that were peeled off from each other in one take-up line were wound up separately using a center-drive biaxial winding machine.

A sheet having such an embossed pattern on both sides had a tsubo of N670 and a diameter of 4π, and the charging voltage of the sheet was measured to be 0.2 KV or less. Therefore, this sheet exhibits good properties such as no charging, low unwinding resistance, and little blocking even when the sheets are stacked.

Modularization of a solar cell using the filled and bonded N'JFA sheet formed in this manner was carried out in the following manner. That is, a primer prepared by dissolving 3% by weight of r-methacryloxypropyltrimethoxysilane (Shin-Etsu Chemical KBM 503) in an aqueous solution whose pH was adjusted to 2 to 3 with acetic acid was added to a reinforced white plate glass (thickness 3wn). and polyvinyl fluoride sheet (DuPont product Tetra-4
00BS 30 WH) was coated on the surface to be contacted, and the solvent was dried.

A sheet with the embossed pattern is placed on top of the tempered white glass, a plurality of silicon semiconductor wafers for solar cells are arranged in series using an interconnector, and the embossed pattern is applied again on top of the sheet. The prepared sheet was then coated with a polyvinyl fluoride sheet, a polyester film (0.5 mm thick) and an aluminum plate (0.5 mm thick).
5fi) were sequentially stacked to form a laminate.

This laminate is placed in the lower chamber of a vacuum laminator whose degassing chamber is separated into two chambers by silicone rubber, and first both chambers are 1 +
Reduce the pressure to nmHg and then! l: Place the vacuum laminator in an oven at 30°C, raise the temperature at a rate of 4°C/min, and when it reaches 120°C, return the upper chamber of the vacuum laminator to atmospheric pressure over a period of 1 minute, and during this time further heat to 150°C. The humidity was increased to ℃, and the temperature and pressure were increased. After continuing heating and pressurizing for another hour in this state, the vacuum laminator was removed from the laminate by cooling and returning the lower chamber to atmospheric pressure, and the aluminum plate and i 1J ester film were sequentially removed.
Got the module.

No air bubbles were observed in this module, and there was no abnormality in the power generating element. Furthermore, a heat cycle test was conducted on this module, with one cycle consisting of 4 hours at a high temperature of 90°C and 4 hours at a low temperature of 40°C.
No abnormality was observed in the module after 0 cycles in its appearance, including the arrangement of the power generation elements.

Example 2 Ethylene-vinyl acetate copolymer (Mitsui Polychemical product EVAFLEX+1501 33% by weight of vinyl acetate nails,
Melt Index 309/10 minutes) 100 copies, 2,
5-dimethyl-2,5-bis(tert-butylperoxy)
1.4 parts of hexane, 025 parts of 2-hydroxy-4-n-octylbenzophenone, 0.1 part of bis(2°2.6.6-tetramethyl-4-piperidine) sebacate and tris (mixed mono-di- nonylphenyl) phosphite 0
．． Two parts were triblended in the same manner as in Example 1.

The molten web extruded from the T-die was embossed in the same manner as in Example 1. However, the processing paper used was one embossed with a diamond lattice pattern (lattice spacing: 1 + nm, depth Q, 4 mm), and a satin roll (matte depth: 0.15111 m) was used as the cooling roll.

The sheet with such embossed patterns on both sides has a basis weight of 7702.4, and no air bubbles were observed in the module made using this sheet in the same manner as in Example 1. There was also no abnormality in the power generation element. Furthermore, this module was subjected to a heat cycle test for 20 cycles, and no abnormality was observed in the module after the test, including the arrangement of the 11° C. emitting elements.

Example 3 It was blended and an embossed sheet was formed.

The obtained sheet with the embossed pattern on both sides had a basis weight of 800 mmA, and no air bubbles were observed in the module made using this sheet in the same manner as in Example 1. There was also no abnormality in the power generation element. Furthermore,
A 20-cycle heat cycle test was conducted on this module, but no abnormality was observed in the module after the test, including the arrangement of the power generation elements.

Example 4 Between the two sheets of the braimer-treated tempered white glass of Example 1,
The sheets each having the embossed pattern used in Example 1 on both sides as the intermediate layer were stacked together, placed in a vacuum laminator, and reduced to 1 Hg at room temperature. ℃ oven, heated to 150℃ over 20 minutes, and then further heated to 1.
It was heated under reduced pressure at 50° C. for 1 hour. It was taken out from the open, cooled, and returned to atmospheric pressure.

The obtained laminated glass has a thickness of 6,4±Q, l Ihm
No bubbles were observed, and the light transmission i at 450 nm was
The third rate was 86%, which was good.

Example 5 Ethylene-vinyl acetate copolymer Z used in Example 2
2.0 parts of vinyltrimethoxysilane and 0.2 parts of di-tert-butyl peroxide were added to OOM and extruded from a screw-type extrusion shell at 200°C to obtain a silane-modified ethylene-vinyl acetate copolymer (melt index 9, 710 minutes,
190°C).

When the undecomposed tertiary butyl peroxide in this silane-modified copolymer was extracted with methanol and analyzed by gas chromatography, the content was found to be less than the original weight percent. Furthermore, when the silane groups in the copolymer were measured by ashing analysis, the content was 1.5% by weight.

A sheet using such a silane-modified ethylene-vinyl acetate copolymer instead of an unmodified ethylene-vinyl acetate copolymer and having molded embossed patterns on both sides in the same manner as in Example 1 had a basis weight of No air bubbles were observed in the module made using this sheet in the same manner as in Example 1, and there was no abnormality in the power generating element. Furthermore, regarding this module, 2
A 0-cycle heat cycle test was conducted, but no abnormality was observed in the module after the test, including the arrangement of the power generation elements.

Example 6 In Example 1, without using process paper, the second
A single-sided embossed sheet was obtained as shown in the figure.

Using this single-sided embossed sheet and the process paper used in Example 1, a sheet with embossed patterns on both sides was molded in accordance with the steps shown in Figure @2.

The basis weight of this sheet was 650 g/U, and no air bubbles were observed in the module made using this sheet in the same manner as in Example 1, and no abnormality was found in the power generating element. Furthermore, this module was subjected to a 20-cycle heat cycle test, but no abnormality was observed in the module after the test, including the arrangement of the power generation elements.

Comparative Example 1 In Example 1, other ethylene-vinyl acetate copolymer (Mitsui Polychemical product Evaflex +550, vinyl acetate content @ 14%, melt index 159/1)
The molten web was extruded at a resin temperature of 110° C. to form a sheet with embossed patterns on both sides.

When a laminated glass was made using this sheet in the same manner as in Example 4, its light transmittance was 68%.

Comparative Example 2 In Example 1, a sheet with embossed patterns on both sides was molded without adding tertiary-butyl peroxybenzoate, and then a module was created using this sheet.

Although no air bubbles were observed in the obtained module,
A part of the power generating element was found to be broken. Furthermore, in the heat cycle test, the arrangement of the power generating elements was partially disordered after 20 cycles. Furthermore, it was found that the laminated glass produced in the same manner as in Example 4 had a thickness of 1.1 to 1.6 mm, and that the embossed sheet used as the interlayer film had significant fluidity.

Comparative Example 3 In Example 1, a sheet with an embossed pattern on only one side (the depth of unevenness on the embossed surface was 0.15 to 0.2, without using the embossed 1I31# paper at all) The diameter of the embossed surface was 0.03 a or less).

When the electrostatic voltage on the non-embossed surface of the sheet was measured, it was found to be 0.
It was 3 to 1,8 KV and was quite charged.

Further, when an attempt was made to unwind a part of the sheet from the roll of the sheet, blocking occurred and unwinding was not easy. Furthermore, when a module was created using this sheet, the presence of air bubbles was observed in some of the modules.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are both schematic diagrams showing one embodiment of the method for forming a filled adhesive sheet according to the present invention. In these drawings, 1 is a T-die, 2 is a molten web, 4 is an embossed release paper, 5 is a roll with an embossed pattern, 6 is a pressure rubber roll, 7 is a secondary cooling roll, 10 and 1] 2 indicates a take-up roll, and 15 indicates an infrared heater. Representative Patent Attorney Yoshi 1) Kayo Figure 1 Figure 2

Claims (1)

[Claims] 1. A filled adhesive sheet for a solar cell module, which is molded from a molding material containing an ethylene copolymer and an organic peroxide, and has an embossed pattern on both sides thereof. 2. The filled adhesive sheet 03 according to claim 1, which is provided with an embossed pattern with a depth of 0.03 M or more, and which is molded from a molding material that further contains a coupling agent. The filled adhesive sheet according to item 1. 4. The filled adhesive sheet according to claim 1, wherein the ethylene copolymer is used as a molding material as a silane-modified ethylene copolymer and is molded. 5. The filled adhesive side sheet according to claim 4, which is molded from a molding material containing a silanol condensation catalyst together with an organic peroxide. 6. The filled adhesive sheet according to claim 1, which is used in a solar cell module in which a lower substrate protective material, a filled adhesive sheet, a solar cell element, a filled adhesive sheet, and an upper transparent protective material are laminated. 7. A filling adhesive sheet is used as an intermediate layer, and an upper transparent protective material and a lower substrate protective material in which a solar cell element is formed on the inward surface of one of the protective materials are stacked above and below the intermediate layer filling adhesive sheet. A filled adhesive sheet according to claim 1, which is used in a solar cell module. 8. Extruding the tri-blended molding material containing an ethylene copolymer and an organic peroxide as a molten web through a T-die extruder at a temperature at which the organic peroxide does not substantially decompose, and embossing it. A method for producing a filled adhesive sheet with embossed patterns on both sides, which is characterized by passing the released release paper between a cooling roll on which an embossed pattern is engraved and a pressure bonding rubber roll, and cooling and solidifying the filled adhesive sheet. 9. A tri-blend molding material containing an ethylene-based copolymer and an organic peroxide is extruded as a molten web from a T-die extruder at a temperature at which the organic peroxide does not substantially decompose to form an embossed pattern. I+- is passed through between a cooling roll engraved with I+- and a pressure-bonding rubber roll, and once cooled and solidified to form a single-sided embossed sheet, a release paper is placed on the non-embossed side of the single-sided embossed sheet, and it is processed in-line or off-line. , the surface of the web not in contact with the release paper is heated again to a temperature at which the organic peroxide does not substantially decompose, the release paper layer web is passed between the roll and the pressure rubber roll, and the web is pressed and solidified by cooling. A method for manufacturing a filled adhesive sheet with an embossed pattern on both sides.