JP2011152720A - Method for manufacturing resin sealing sheet and resin sealing sheet - Google Patents

Abstract

An object of the present invention is to provide a production method capable of efficiently producing a resin-sealed sheet having excellent adhesion and creep resistance and a low thermal shrinkage rate.
SOLUTION: A film forming process in which a resin is melt-extruded from an annular die (10) to form a cylindrical shape, and a side surface of a cylindrical extrudate obtained by the film forming process is crushed to obtain a flat plate-like extrusion. A method for producing a resin-encapsulated sheet, comprising: a molding step for performing at least a product.
[Selection] Figure 1

Description

  The present invention relates to a method for producing a resin sealing sheet and a resin sealing sheet obtained thereby.

  In recent years, solar power generation has attracted attention as a clean power generation method using solar energy. Photovoltaic power generation directly converts solar energy into electric power, and is performed by a solar cell module. Since solar cell modules are often installed outdoors, they are exposed to wind and rain for a long time. The power generation part is sandwiched between resin sealing sheets, the outside is further covered with glass or a back sheet, and the whole is integrated (modularized) by laminating them at a high temperature. This prevents the ingress of moisture from the outside and protects the power generation part and prevents leakage. Since the surface for receiving sunlight (power generation surface) needs to transmit light necessary for power generation, transparent glass or transparent resin is used for the substrate of the power generation surface. An aluminum foil called a back sheet, polyvinyl fluoride resin (PVF), polyethylene terephthalate (PET), or a laminated resin sheet obtained by subjecting them to a barrier coating is used for the substrate on the back surface (non-power generation surface) of the power generation portion.

  Here, as performance required for the resin sealing sheet, <1> adhesion to glass, power generation portion, back sheet, etc., <2> flow of power generation portion due to melting of the resin sealing sheet in a high temperature state Prevention (creep resistance), <3> transparency that does not inhibit sunlight, and the like.

  Usually, an ethylene-vinyl acetate copolymer (hereinafter sometimes referred to as EVA) is used as the resin sealing sheet. EVA is blended with additives such as light-resistant agents, UV absorbers, coupling agents for improving adhesion to glass, and organic peroxides for cross-linking as countermeasures against UV degradation. A sheet formed by a film forming method is used. When such an EVA-based resin encapsulating sheet is used, the resin encapsulating sheet is melted through a preheating process and a pressing process at a temperature equal to or higher than the melting temperature of the resin to be used (in the case of EVA, a temperature condition of about 150 ° C.). The members are bonded and integrated. As a method for producing such a resin encapsulating sheet for solar cells, a method using an annular die, a T-die film forming method, a calendar film forming method, and the like are mainly employed.

  As a method using an annular die, for example, a resin melted at a high temperature is extruded into an annular shape from an annular die to form a cylindrical shape, and after cooling and solidifying the cylindrically formed sheet, one end of the sheet is formed by a nip roll. There is a method of sealing and blowing air to form a cylindrical extrudate, which is cut open and wound up as a flat sheet. The method using an annular die allows high-speed film formation with inexpensive equipment.

  As a T-die film forming method, for example, Patent Document 1 discloses a resin-encapsulated sheet containing an organic peroxide as a cross-linking agent and forming a film by melting and extruding a resin from a T-die.

  As a calendar film forming method, for example, Patent Document 2 discloses a resin-encapsulated sheet containing an organic peroxide as a crosslinking agent and forming a film by a calendar film forming method.

Japanese Patent Publication No. 1-52428 JP 2000-84967 A

  However, when a soft resin is used in the method using an annular die, it is difficult to open the cylindrical extrudate after film formation because the inner surfaces of the side surfaces of the cylindrical extrudate are likely to block each other (internal blocking). There is a problem that it is difficult to form a single sheet. This tendency is remarkable when a film is formed using the inflation method.

  In the T-die film forming method disclosed in Patent Document 1 and the like, since there are many staying parts in the T-die, the temperature history and staying time in the T-die are different between the sheet center part and the sheet end part. Variations in film thickness and performance occur between parts. In addition, it is not simple because it is necessary to frequently replace the die in accordance with the desired sheet width during film formation. Since the melt-extruded resin cools rapidly, orientation occurs in the sheet. When such an orientation occurs, the resin-sealed sheet contracts when the solar cell is modularized, causing a shift or breakage of the power generation portion. In order to remove this orientation, an additional annealing process is required, which increases the number of steps during film formation and causes problems such as variations in film thickness and poor flatness.

  In the calendar film forming method of Patent Document 2 or the like, since the influence of the melt viscosity of the resin is large, there are problems that the resin that can be used is limited and a sheet having a multilayer structure cannot be formed.

  This invention is made | formed in view of the said situation, and it aims at providing the manufacturing method which can manufacture efficiently the resin sealing sheet | seat which is excellent in adhesiveness and a creep-proof characteristic and has a low heat shrinkage rate. .

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have made a film-forming process in which a resin is melt-extruded from an annular die to form a cylindrical shape, and a cylindrical extrudate obtained by the film-forming process. The present invention has been completed by finding that the above-mentioned problems can be solved by using a production method including at least a forming step of forming a flat extrudate by crushing the side surface of the sheet.

That is, the present invention is as follows.
[1]
A film forming step of melt-extruding resin from an annular die to form a cylindrical shape;
A molding step for at least making a flat extrudate by crushing the side surface of the cylindrical extrudate obtained by the film forming step;
The manufacturing method of the resin sealing sheet containing this.
[2]
The method for producing a resin-encapsulated sheet according to [1], wherein, in the film-forming step, the cylindrical extrudate is formed by an inflation method in which the resin is melt-extruded from the annular die in an upward direction or a downward direction.
[3]
The method for producing a resin-sealed sheet according to [1] or [2], further comprising a cooling step of cooling and solidifying the extrudate melt-extruded from the annular die by water cooling or air cooling.
[4]
The method for producing a resin-encapsulated sheet according to any one of [1] to [3], wherein the annular die is a multilayer annular die.
[5]
In the molding step, after the side surfaces of the cylindrical extrudate are overlapped with a stabilizer, the side surfaces of the extrudate are crushed by a nip roll to obtain a flat extrudate [1] to [4] ] The manufacturing method of the resin sealing sheet as described in any one of.
[6]
The method for producing a resin-encapsulated sheet according to any one of [1] to [5], further including a step of embossing and / or satin finishing after the flat extrudate is softened.
[7]
The method for producing a resin-encapsulated sheet according to [6], wherein the softening is performed by at least one method selected from the group consisting of infrared heating, hot air heating, and a heating roll.
[8]
The method for producing a resin-sealed sheet according to any one of [1] to [7], further comprising a step of subjecting the flat extrudate to a crosslinking treatment by irradiation with ionizing radiation.
[9]
The resin comprises (a) (a1) ethylene monomer and (a2) at least one monomer selected from the group consisting of vinyl acetate, aliphatic unsaturated carboxylic acid and aliphatic unsaturated carboxylic acid ester. The method for producing a resin-encapsulated sheet according to any one of [1] to [8], which is a resin containing at least one selected from the group consisting of a polymer and (b) a polyolefin-based resin.
[10]
The resin sealing sheet has a multilayer structure, and the surface layer of the resin sealing sheet contains an olefin resin having a hydroxyl group, a modified polyolefin resin terminal-modified or graft-modified with an acidic functional group, and glycidyl methacrylate. The method for producing a resin-encapsulated sheet according to any one of [1] to [9], comprising at least one adhesive resin selected from the group consisting of ethylene copolymers.
[11]
The resin sealing sheet manufactured by the method as described in any one of [1]-[10].
[12]
A translucent insulating substrate;
A backsheet,
A power generating element disposed between the translucent insulating substrate and the backsheet;
The resin sealing sheet according to [11], wherein the power generating element is sealed between the translucent insulating substrate and the back sheet;
A solar cell module comprising:

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in adhesiveness and a creep-proof characteristic, the manufacturing method which can manufacture efficiently the resin sealing sheet with a low heat shrinkage rate can be provided.

It is the schematic which shows an example of the manufacturing method of the resin sealing sheet which concerns on this Embodiment. It is a schematic top view which shows an example of the embossing shape given in the manufacturing method of this Embodiment. FIG. 3 is a cross-sectional view taken along line A-A ′ of FIG. 2. It is a schematic top view which shows another example of the embossing shape given in the manufacturing method of this Embodiment. It is sectional drawing which follows the B-B 'line of FIG. It is the schematic which shows an example in the case of performing an embossing shape or a satin finish in the manufacturing method of the resin sealing sheet which concerns on this Embodiment. It is sectional drawing which shows the one aspect | mode of the solar cell module which concerns on this Embodiment.

  Hereinafter, modes for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail with reference to the drawings as necessary. The following embodiments are exemplifications for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be implemented with appropriate modifications within the scope of the gist thereof. In the drawings, positional relationships such as up, down, left and right are based on the positional relationships shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

FIG. 1 is a schematic view showing an example of a method for producing a resin-encapsulated sheet of the present embodiment.
The method for producing the resin sealing sheet of the present embodiment is as follows:
A film forming step of melt-extruding the resin from the annular die 10 to form a cylindrical shape;
A molding step for at least making a flat extrudate by crushing the side surface of the cylindrical extrudate obtained by the film forming step;
including.

  In the manufacturing method of the present embodiment, a cylindrical extrudate is obtained in the film forming step, but the side surface is crushed without cutting it into a flat extrudate. As a result, a resin-sealed sheet having no variation in sheet thickness and having a small thermal shrinkage can be easily and economically produced without internal blocking. The resin-encapsulated sheet thus obtained has excellent adhesion and creep resistance, has a low thermal shrinkage rate, and further has a uniform sheet thickness, so there is no variation in physical properties depending on the part of the sheet. It can use suitably as a resin sealing sheet of a battery module.

(Film forming process)
The resin is melt-kneaded by the extruder 12 to obtain a kneaded product, and this kneaded product is sent to the annular die 10 through the polymer pipe 14 and extruded from an opening (not shown) of the annular die 10 to form a cylindrical shape. Let it be an extrudate. Cylindrical extrudates are sometimes called tubes, tubular films, and the like.

  The kind of extruder 12 is not specifically limited, A well-known thing can also be used. For example, a uniaxial screw extruder, a biaxial screw extruder, etc. are mentioned. In the present embodiment, one extruder 12 or a plurality of extruders 12 may be used. Although it is possible to form a film even if there is only one extruder, it is preferable to use two or more extruders from the viewpoint of producing not only a single-layer resin-encapsulated sheet but also a multilayer resin-encapsulated sheet. . It is more preferable to use 2 to 5 extruders from the viewpoints of controllability in the manufacturing process and simplicity of the installation configuration.

  The polymer pipe 14 is a pipe that connects the annular die 10 and the extruder 12, and is used for transferring the kneaded material melted and kneaded by the extruder 12 to the annular die 10. The shape and size of the polymer pipe 14 are not particularly limited, and can be a suitable shape and size depending on the components and amount of the kneaded product. For example, the polymer pipe 14 may have a branched structure. A structure may be adopted in which the polymer pipes 14 are respectively connected to two or more resin insertion ports (not shown) of the annular die 10 by connecting the branched polymer pipes 14 to one extruder 12. In order to remove unmelted resin and foreign matter, it is preferable to arrange at least one metal mesh (not shown) before and after the polymer pipe 14.

  As the annular die 10, a known annular die that is commercially available can be used. For example, when forming a film by the inflation method described later, a manifold type die or mandrel type die that supplies the kneaded resin from the side surface, a spider type or spiral type that supplies the kneaded resin from the center (spiral mandrel type, star spiral type) Etc. can be used. Among these, a multilayer annular die is preferable from the viewpoint of easily producing a resin-sealed sheet having a multilayer structure.

  The multilayer annular die is preferable because it can be laminated with a plurality of resins at a stage before being extruded from the die by being connected to the plurality of extruders 12 via the polymer pipe 14. By using a multilayer annular die, a resin-sealed sheet having a multilayer structure composed of a plurality of resin layers can be efficiently produced. For example, a sheet in which three types of resins are laminated can be formed by connecting three types of resins from three extruders 12 to a multilayer annular die by polymer pipes 14 and extruding them. Furthermore, by using a branched polymer pipe, it is possible to stack a plurality of resins of the same type of composition multiple times, and it is possible to manufacture a resin-sealed sheet having a multilayer structure having more layers than the number of extruders 12 used. Therefore, the production efficiency is further improved. The resin-encapsulated sheet having a multilayer structure will be described later.

  The annular die 10 may have air holes for blowing air into the extruded cylindrical extrudate. In the inflation method, a cylindrical extrudate obtained by extruding resin from the annular die 10 is folded by a stabilizer 16 and the ends of the cylindrical extrudate are sealed by a pair of nip rolls 18 to be described later, and air leaks. Air is blown into the inside of the cylindrical extrudate. Thereby, the molten resin immediately after being extruded from the annular die 10 is stretched. At that time, a particularly thick portion is preferentially stretched. Thereby, the film thickness can be made uniform without uneven thickness, and thus the film thickness accuracy is excellent. Here, the inflation method refers to a method of performing at least expansion by putting air or the like into the extrudate from the annular die 10. The amount of air blown is not particularly limited, and can be determined based on the expandability (for example, blow ratio) of the cylindrical extrudate. The blow ratio is defined by the ratio of the diameter of the cylindrical extrudate to the diameter of the annular die 10. In order to form a film stably, the value of the blow ratio is preferably in the range of 0.5 to 5, more preferably in the range of 0.5 to 3, and in the range of 0.7 to 3. More preferably it is. By setting it as the blow ratio of the said range, while being able to improve the film thickness precision of the obtained extrudate, further thickness reduction is attained.

  The direction of extruding the molten resin from the annular die 10 is not particularly limited, and may be any of an upward direction, a horizontal direction, and a downward direction, but in the inflation method, it is preferably an upward direction or a downward direction. When pulling out the resin in the downward direction, it is more preferable to form a film by extruding a resin having a high melt tension. In the case of pulling upward, it is more preferable to form a film by extruding a resin having a low melt tension.

  The extrudate melt-extruded from the annular die 10 is preferably cooled by water cooling or air cooling. Here, the water cooling is a method of cooling the melt-extruded cylindrical extrudate by bringing it into contact with running water (hereinafter sometimes referred to as “water cooling method”). Air cooling is a method of cooling by blowing air at a temperature lower than the temperature of the molten resin (hereinafter sometimes referred to as “air cooling method”).

  Since the water cooling method is limited by the size of the cooling device, the winding width (sheet width) of the extrudate is smaller than that of the air cooling method. However, since the extrudate can be cooled quickly, a shrinkable resin can be used. It is suitable for forming a film or forming a highly transparent resin. The method of water cooling is not particularly limited, and examples thereof include a method of bringing the inner and outer surfaces of the formed extrudate into contact with a water cooling jacket, a method of cooling with a water tank, and the like.

  Since the air cooling method cools the extrudate slowly compared to the water cooling method, the orientation produced during melt extrusion and winding can be relaxed, so when forming a resin sheet with a particularly low shrinkage rate, This is suitable for forming a wide resin sheet. The method of air cooling is not particularly limited, and includes a method of blowing air to the outside of the cylindrical extrudate with an air ring device, a method of blowing air to the inside of a tubular resin sheet, and a method of using these in combination. . As a result, the extrudate can be cooled and solidified simultaneously with expansion. One air ring device may be used alone, or a plurality of air ring devices may be used, but it is preferable that the number of air ring devices is 1 to 3 from the viewpoint that the device configuration does not become large.

(Molding process)
Subsequently, as a forming step, after the inner surfaces of the side surfaces of the cylindrical extrudate obtained by the film forming step are overlapped with the stabilizer 16, the side surface of the extrudate is crushed from the outside with a nip roll 18 to form a cylinder. The side surfaces of the shaped extrudate can be integrated. Thereby, it can be set as a flat extrudate. For example, in the past, the use of an inflation method as one of the methods for producing a resin encapsulated sheet for solar cells has been studied, but when a formed cylindrical extrudate is cut into a flat plate shape, the extrusion method is used. Since the side surfaces of the product are internally blocked, a uniform film thickness cannot be obtained. Therefore, it cannot be said that the method is suitable as a method for producing a resin-encapsulated sheet that requires film thickness accuracy and the like. However, in the present embodiment, the cylindrical extrudate is not cut open, but the side surfaces are crushed and integrated into a single sheet, so the problem of internal blocking does not occur. As a result, a resin-encapsulated sheet having a uniform film thickness and physical properties can be stably formed while maintaining the advantages of conventional inflation. In the present embodiment, it is only necessary to obtain a flat extrudate by crushing at least the side surface of the cylindrical extrudate, and the method is not particularly limited, but the side surfaces of the cylindrical extrudate are overlapped. After that, the side surface of the extrudate is preferably crushed by the nip roll 18.

  The method for superimposing the side surfaces of the cylindrical extrudate is not particularly limited, but the stabilizer 16 is preferably used. Before the side surfaces of the cylindrical extrudate are crushed and integrated, the side surfaces of the extrudate are overlapped by the stabilizing plate 16, so that the positioning accuracy of the overlay can be improved. Here, the stabilizing plate 16 may be any material as long as it can overlap at least a part of the side surface of the extrudate by guiding the side surface of the cylindrical extrudate, and may also be called a guide plate or a guide. is there. The shape and size of the stabilizing plate 16 are not particularly limited, and for example, a known stabilizing plate used in the inflation method can be used. Before the end of the blown cylindrical extrudate is sealed with the nip roll 18, the cylindrical extrudate is folded by the stabilizer 16 or the like, thereby effectively suppressing the generation of wrinkles during sealing. it can. The surface of the stabilization plate 16 is preferably coated with a non-adhesive resin such as a fluororesin from the viewpoint of preventing adhesion of resin or the like.

  The nip roll 18 is composed of a pair of rolls and is disposed behind the stabilizer plate 16 (that is, downstream of the line). The end of the extrudate folded by the stabilization plate 16 is sealed with a nip roll 18 so that air does not escape when air is blown from the annular die 10. In the present embodiment, the extrudate is sealed with the nip roll 18 and the inner surfaces of the extrudate are brought into close contact with each other so as to be integrated into a flat extrudate. The surface of the nip roll 18 is preferably covered with a non-adhesive resin such as a fluororesin from the viewpoint of preventing adhesion of a resin or the like, similar to the stabilizer 16 described above.

  The stabilizer plate 16 and the nip roll 18 may be fixed on the production line, but may be provided with a mechanism that rotates to twist the bubble. By rotating the stabilizer plate 16 and the nip roll 18, the unevenness of the thickness of the resin sheet S in the width direction can be further reduced. After the cylindrical extrudate is folded by the stabilizer 16, the inner surface is integrated by the nip roll 18, and the flat resin sheet S can be obtained. The resin used in the present embodiment may be one type or a mixture of two or more types of resins. When two or more kinds of resins are used, when they are melt kneaded by the same extruder, it is preferable to uniformly mix them in advance. Moreover, the manufacturing method of this Embodiment can manufacture the resin sealing sheet of either a single layer structure or a multilayer structure, However, It is especially suitable for manufacture of the resin sealing sheet of a multilayer structure.

  A resin-sealed sheet having a multilayer structure can be efficiently produced by using the annular die 10. For example, in the case of a 3 type 5 layer multilayer structure, 3 types of resin are stacked and melt extruded from an annular die to form a 3 type 3 layer cylindrical extrudate. The innermost layers are brought into close contact and integrated. Thereby, it can be set as the symmetrical 3 type | mold 5 layer resin sheet S which is a layer structure called "surface layer / inner layer / integrated innermost layer / inner layer / surface layer". Here, “surface layer” refers to the outermost layer of the cylindrical extrudate, “innermost layer” refers to the innermost layer of the cylindrical extrudate, and “inner layer” refers to the surface layer and outermost layer. A layer located between the inner layer. In the present embodiment, one type of resin may be used for each layer, or a mixture of two or more types of resins may be used. The inner layer here may be a single layer or may be composed of two or more layers.

  When the resin sheet S having a multilayer structure with two types and three layers is used, two types of resins are stacked and melt-extruded from the annular die 10 to form a two-type two-layer cylindrical extrudate, and the side surfaces of the extrudate are crushed. Thus, a multilayer structure of “surface layer / integrated inner layer / surface layer” can be obtained. The number of resin layers constituting the inner layer may be one or a mixture of two or more resins. The above-described three-kind five-layer multilayer structure and two-kind three-layer multilayer structure are examples of the multilayer structure, and the number of layers can be increased to five or more by the above method.

  When the resin sheet S having a single-layer structure is used, one type of resin is stacked and melt extruded from the annular die 10 to form a one-layer / one-layer cylindrical extrudate, and the side surface of the extrudate is crushed. A resin-sealed sheet having a layer structure can be obtained.

  According to the manufacturing method of the present embodiment, when the integrated resin sheet S is viewed in cross section, a multilayer resin sheet S whose layer structure is substantially symmetric in the thickness direction of the sheet can be efficiently formed. When it is set as a multilayer resin sealing sheet, the resin sealing sheet may bend by the difference in a thermal expansion coefficient because the layer structure is asymmetric in the thickness direction of a sheet | seat. However, according to the present embodiment, such bending can be prevented. Here, the state in which the layer structure is asymmetric in the thickness direction of the sheet corresponds to at least one of the case where the surface layer of the resin sheet S is a different type of resin between the front and the back, or a different thickness. I mean.

  In the present embodiment, it is preferable to further include a step of embossing and / or satin finishing after softening the flat extrudate, and more preferably both. By performing embossing or matte processing on the surface of the resin sheet S, irregularities are formed on the surface of the sheet, so that air bleedability and blocking resistance when used as a sealing material can be improved.

  According to the manufacturing method of the present embodiment, even a fine embossed shape can be transferred with high accuracy. The embossed shape is not particularly limited, and examples thereof include a quadrangular pyramid shape (pyramid shape), a quadrangular frustum shape, a striped pattern, a textured pattern, a satin pattern, a skin pattern, a diamond lattice, and a wrinkle pattern. The ratio of the total area of the embossed convex portions on the embossed surface is preferably 5 to 50% from the viewpoint of the sealing ability and blocking resistance of the resin sealing sheet.

  FIG. 2 is a schematic view showing an example of an embossed shape applied in the manufacturing method of the present embodiment. FIG. 3 is a cross-sectional view taken along the line A-A ′ of FIG. 2. The emboss shape shown in FIGS. 2 and 3 is a quadrangular pyramid shape (so-called pyramid shape), and the depth of the emboss shape is D1 (see FIG. 3). When the surface of the solar cell encapsulating sheet has a square pyramid-shaped embossed shape, the solar cell encapsulating sheet abuts against an object to be encapsulated (for example, a power generation cell) at the apex of the quadrangular pyramid to seal.

  FIG. 4 is a schematic diagram showing another example of the embossed shape applied in the manufacturing method of the present embodiment. FIG. 5 is a cross-sectional view taken along line B-B ′ of FIG. 4. The emboss shape shown in FIGS. 4 and 5 is a square frustum shape (so-called trapezoidal cup shape), and the depth of the emboss shape is D2 (see FIG. 5). When the surface of the solar cell encapsulating sheet has a square frustum-shaped embossed shape, the top surface of the quadrangular frustum-shaped top is in contact with the object to be sealed.

  The embossed shape may be provided on at least one surface of the resin sheet S, or may be provided on both surfaces of the resin sheet S. When embossing is performed, the depth of the embossed shape to be shaped is not particularly limited, but the depth is preferably 20 to 400 μm from the viewpoints of air bleeding and blocking resistance. The lower limit of the depth of the embossed shape is preferably 20 μm or more, more preferably 40 μm or more, still more preferably 80 μm or more, and even more preferably 90 μm or more. The upper limit is preferably 400 μm or less, more preferably 350 μm or less, still more preferably 310 μm or less, still more preferably 200 μm or less, and even more preferably 100 μm or less. Here, the depth of the embossed shape means the depth from the embossed convex part to the embossed concave part when the embossed surface of the resin-encapsulated sheet is viewed in cross section (for example, D1 in FIG. 3 and FIG. 5). D2).

  From the viewpoint of blocking resistance, the surface roughness (Ra) of the pear ground formed by pear finish is preferably 2 μm to 10 μm, more preferably 2 μm to 9 μm, and even more preferably 4 μm to 8 μm. Here, pear ground refers to a surface on which irregular fine irregularities are formed, and is generally a surface that is rough like the surface of a pear skin. The surface roughness (Ra) of the satin surface can be measured using, for example, a laser microscope (manufactured by Keyence Corporation).

  By applying a satin finish to the surface of the resin sealing sheet, it is possible to improve the air release property and the blocking resistance. In the case of a satin finish, since it can be simply processed by using a satin roll described later, production efficiency is good. In particular, it is excellent in production efficiency from the viewpoint that the sheet surface can be reliably shaped even at a high film forming speed.

  A case where embossing and matte finish are used together in the present embodiment (hereinafter sometimes referred to as embossing with satin finish) will be described. For example, in the case of the square pyramid-shaped (so-called pyramid-shaped) embossed shape shown in FIGS. 2 and 3, the pear-ground surface of the embossed sheet with a pear-finished surface may be formed on at least a part of the embossed convex surface. 2 and 3, it is sufficient that a satin shape (not shown) is formed in at least a part of the peripheral area of the apex of the quadrangular pyramid shape, and the embossed shape is formed as the satin shape. It does not necessarily have to be formed on the entire surface.

  In the case of the quadrangular frustum shape shown in FIGS. 4 and 5 (so-called trapezoidal cup shape), the satin finish is formed on the top surface (convex surface) of the square frustum shape, and the object to be sealed is a square pyramid. It is sealed by contact with a trapezoidal top surface. The pear ground of the embossed sheet with a pear finish is only required to be formed on at least a part of the embossed convex surface. In the case of FIGS. The shape (not shown) is only required to be formed, and the matte shape is not necessarily formed on the entire surface where the embossed shape is formed.

  The textured surface of the embossed sheet with a textured surface may be formed on at least a part of the surface of the embossed convex part, but is preferably formed on 50% or more of the total surface area of the embossed convex part. % Or more is more preferable, 80% or more is more preferable, 90% or more is further more preferable, and it is still more preferable that it is formed on the entire surface (100%).

  Even if the embossed shape is shallow, the resin-encapsulated sheet subjected to both the satin finish and the emboss finish has a satin finish and is excellent in air escape and blocking resistance. For example, even if the depth of the embossed shape is so fine that air bleedability and blocking resistance are not sufficiently obtained, by making a resin-sealed sheet further having a textured surface, air bleedability and blocking resistance Can also be improved. Therefore, in this embodiment, even when the depth of the embossed shape has to be reduced due to the limitation of manufacturing conditions, etc., by making the embossed shape with a satin finish, the air release property and resistance of the resin encapsulated sheet can be reduced. Blocking property can be improved.

  When making the embossed shape deeper or more complicated to improve air escape and blocking resistance, it is necessary to reduce the film forming speed so that the embossed shape to be transferred does not collapse. There may be restrictions. With resin-encapsulated sheets that have been both textured and embossed, even with a shallow embossed shape, having a textured surface can demonstrate excellent air release and blocking resistance, so the film-forming speed is higher. It can also be. For example, in the manufacturing method of the present embodiment, since the film forming speed can be 15 m / min or more, a manufacturing method with excellent production efficiency can be obtained, but the depth of the embossed shape is made shallower. The film forming speed can be further increased by, for example. As described above, according to the manufacturing method of the present embodiment, it is also possible to manufacture a resin-encapsulated sheet having excellent air escape properties and blocking resistance with high production efficiency.

  When embossing is applied to the resin sheet S, or when the matte finish is applied, or when both the embossing and the satin finish are applied, as a method of softening the resin sheet S, the resin sheet S that is an extrudate is reused. For example, a method of pressing the shaping roll having the shape to be transferred on the surface to the surface of the resin sheet S by heating to a molten state can be employed. A method for shaping the embossed shape and the satin finish will be described below.

  FIG. 6 is a schematic diagram illustrating an example of embossing or matte finishing in the method for producing a resin sealing sheet according to the present embodiment. The resin sheet S formed into a sheet shape by the forming process of FIG. 1 is pinched by the pinch roll 24 through the guide roll 22. Then, after the resin sheet S is brought into close contact with the preheating roll 26 and preheated, the main heating is performed using the heating unit 28 such as a heater. By preheating before the main heating, a sufficiently softened state that can be shaped into the resin sheet S can be quickly created without unevenness. Moreover, by performing preheating, it can suppress that the viscosity of the resin sheet S falls extremely, and it can prevent that a sheet | seat is extended and a shrinkage | contraction rate becomes high. As a result, an embossed shape and a satin shape can be formed on the resin sheet S with high accuracy. Thereafter, the resin sheet S is taken up by a take-up roll (not shown) and cut into an appropriate sheet length to obtain a resin-encapsulated sheet.

  The heating method is not particularly limited, but is preferably at least one selected from the group consisting of infrared heating, hot air heating, and a heating roll. Among these, infrared heating is excellent from the viewpoint of being able to efficiently heat up to the center of the sheet and easy to insert deep embossing. Moreover, a heating roll and hot air heating are advantageous at the point which can raise the temperature of the surface which embosses at a stretch, and can create an emboss shape, preventing the expansion | extension of a sheet | seat and suppressing the raise of a shrinkage | contraction rate. Examples of infrared heating include far infrared and near infrared, and an optimum infrared wavelength for achieving a desired temperature may be selected. The said heating method may be used independently or may use 2 or more types together.

  Specifically, preheating is performed using a preheating roll 26 having a temperature relatively lower than the melting point of the resin, and a heating unit 28 (for example, infrared heating, hot air heating, roll heating, etc.) is provided immediately before the shaping roll 30. After the resin surface is softened, an embossed shape, a satin shape, or an embossed shape with a satin finish is formed by pressing with a shaping roll (for example, an embossing roll, a satin roll, or an embossing roll with a satin finish) 30 and a backup roll 32. Can be transferred. Although preheating temperature is not specifically limited, Preferably it is melting | fusing point-20 degreeC-melting | fusing point of resin, More preferably, it is melting | fusing point -20 degreeC-melting | fusing point -3 degreeC.

  As a heating method, first, after pre-heating by being in close contact with a heating roll or the like, the main heating may be performed by infrared heating or the like. After preheating, by performing main heating at a higher temperature, it is possible to quickly achieve a softened state that can be satisfactorily textured or embossed sufficiently. By preheating, the rate of temperature rise is slow, so that it is possible to effectively prevent cases where shaping is difficult or the temperature does not become uniform and becomes uneven. By performing preheating, it is possible to prevent the viscosity of the resin sheet S from being extremely lowered, and thus it is possible to prevent the resin sheet S from being stretched and the shrinkage rate from becoming too high. As a heating method, after preheating by bringing it into contact with a heating roll having a relatively lower temperature than the melting point, immediately before pressing the shaping roll 30, the surface of the resin sheet S is heated by heating with hot air or a specific infrared wavelength. It is preferable to form a desired shape by softening and pressing with a shaping roll 30. Although it does not specifically limit as temperature of preheating, Preferably it is melting | fusing point-20 degreeC-melting | fusing point of resin, More preferably, it is melting | fusing point -20 degreeC-melting | fusing point -3 degreeC. The preheating roll 26 is preferably a non-adhesive surface because it tends not to stretch when the softened sheet is peeled off and tends to have a low shrinkage rate. Non-adhesive processing can be performed by fluorine-based, silicon-based or glass-based coating or surface coating.

  In the present embodiment, it is preferable to perform tension control before and after the cooled and solidified resin sheet S is softened by reheating so that the softened resin sheet S does not stretch. By performing tension control, stretching of the softened resin sheet S is suppressed, and a lower shrinkage tends to be achieved. The tension at the time of tension control is 0.1 to 80N, more preferably 0.1 to 70N, and still more preferably 0.1 to 60N with respect to a sheet width of 1 m.

  As a tension control method, for example, at least one pair or more of pinch rolls 24 (some are not shown) and at least a shaping roll 30 before and after the step of heating and softening the cooled and solidified resin sheet S. And a backup roll 32 are used to pinch and restrain.

  After the resin sheet S is softened, the embossed shape, the satin shape, or the embossed shape with the satin surface can be transferred to at least a part of the surface of the resin sheet S by pressing the shaping roll 30 on the surface. it can. Thus, an embossed shape, a satin shape, or an embossed shape with a satin finish can be formed on the resin sheet S.

  The type, shape, and the like of the shaping roll 30 are not particularly limited, and for example, an embossing roll that is used when shaping the embossed shape, a satin roll that is usually used when performing satin processing, and the like can be used. In addition, when shaping an embossed shape with a satin finish, a roll having an embossed shape on at least a part of the surface and at least a pear ground surface formed on the convex surface of the embossed shape (embossing roll with a satin finish) Can be used.

  As the satin roll, for example, a satin roll having a surface treated by sandblasting on the roll surface, a satin roll having a surface treated by etching on the roll surface, or the like can be used. By adjusting the conditions such as sandblasting and etching described above, the matte shape formed on the roll surface can be controlled. Furthermore, not only the surface roughness but also the glossiness can be controlled by using plating or the like together.

  When the shaping roll 30 presses the surface of the resin sheet S, the shape of the surface of the shaping roll 30 can be transferred to the resin sheet S, but the transfer conditions are not particularly limited, and the shape of the shape to be transferred is Considering the formability and the releasability of the resin sheet S from the shaping roll 30, suitable conditions can be selected as appropriate. For example, the linear pressure between the rolls is preferably 2 kg / cm or more, and more preferably 3 kg / cm or more. Furthermore, it is preferable that the sheet is pressed between the rolls. From the viewpoint of productivity, it is preferable to control the pressing condition by increasing the roll diameter. The roll diameter of the shaping roll 30 is preferably 300 mm or more, more preferably 350 mm or more, and further preferably 400 mm or more.

  The shaping roll 30 has a shape to be transferred to the resin sheet S. For example, when the emboss shape is shaped on the resin sheet S, the shaping roll 30 is an emboss roll. When the matte shape is formed on the resin sheet S, it is a satin roll having a satin surface. Furthermore, when shaping | molding the embossed shape with a satin finish, it is an embossing roll with a satin finish at least one part of the surface is an embossed shape, and the said pear ground is formed at least on the convex-shaped surface of the said embossed shape. Thereby, when using resin sheet S as a resin sealing sheet, blocking can be more effectively controlled when an object to be sealed (such as a power generation element) is sealed, and when a solar cell module is laminated. A gas such as air can be effectively removed. Here, the embossed shape is a shape formed by embossing some uneven shape, and is different from the above-mentioned satin shape.

  The resin sealing sheet of the present embodiment is preferably subjected to a crosslinking treatment. By crosslinking, creep resistance and gap filling properties become better. The crosslinking method is not particularly limited, and a known method can be employed. Examples thereof include irradiation with ionizing radiation (electron beam, γ-ray, ultraviolet ray, etc.) and crosslinking treatment with an organic peroxide. These cross-linking treatments (for example, irradiation treatment when using ionizing radiation, heat treatment when using organic peroxide) are performed as a pre-process of satin processing or embossing processing depending on the respective characteristics and conditions. It may be performed as a post process.

  Here, “crosslinked” means a state in which the gel fraction is preferably 1% by mass or more as a result of physical or chemical crosslinking of the resin. For example, when using the resin sheet S of this Embodiment as a resin sealing sheet of a solar cell, when the resin sheet S is a single layer structure, the gel fraction of a resin layer is 1-65 mass%. It is preferably 2 to 60% by mass, more preferably 2 to 55% by mass.

  When the resin sealing sheet has a multilayer structure including a surface layer and an inner layer, the gel fraction of at least one layer of the surface layer is preferably 1 to 65% by mass, and more preferably 2 to 60% by mass. 2 to 55% by mass is more preferable. When the gel fraction of the surface layer is 1% by mass or more, the creep resistance tends to be good, and when it is 65% by mass or less, the gap filling property tends to be good.

  In the present embodiment, by initially irradiating the sheet having a single layer structure with ionizing radiation from the surface to a predetermined depth, the gelled layer near the surface and the gelled inside A multilayer structure having a surface layer and an inner layer can also be formed by generating a non-layer (or a layer having a low gel fraction). In this case, the layer boundaries may not be clearly distinguishable.

The gel fraction of the resin sealing sheet can be obtained by the following formula from the ratio of the insoluble portion after extracting the resin sealing sheet in boiling p-xylene for 12 hours.

Gel fraction (mass%) = (sample weight after extraction / sample weight before extraction) × 100

  In the case of crosslinking by irradiation with ionizing radiation, the thickness reduction rate can be adjusted by irradiation intensity (acceleration voltage) and irradiation density. In the case of crosslinking with an organic peroxide, the thickness reduction rate can be adjusted by the content of the organic peroxide. Moreover, you may utilize the effect of the bridge | crosslinking acceleration | stimulation or bridge | crosslinking suppression by the difference in the bridge | crosslinking degree by the kind of resin, a transfer agent, etc.

  As a method of crosslinking by irradiation with ionizing radiation, specifically, there is a method of crosslinking by irradiating the resin encapsulating sheet with ionizing radiation such as α rays, β rays, γ rays, neutron rays, and electron beams. Can be mentioned. The acceleration voltage of ionizing radiation such as an electron beam can be selected depending on the thickness of the resin sealing sheet. For example, when the thickness is 500 μm, an acceleration voltage of 300 kV or more is required when the entire resin sealing sheet is crosslinked. is there.

  The accelerating voltage of ionizing radiation such as an electron beam can be appropriately adjusted according to the resin layer subjected to the crosslinking treatment, and the irradiation dose of ionizing radiation varies depending on the resin used, but is generally 3 kGy or more. By this, it exists in the tendency which can bridge | crosslink the whole resin sealing sheet uniformly.

  In the case of crosslinking with an organic peroxide, thermal crosslinking is performed by blending or impregnating the organic peroxide in the resin as a crosslinking agent. In this case, an organic peroxide having a half-life at 100 to 130 ° C. of 1 hour or less is preferable.

  Examples of organic peroxides that have good compatibility and have the above half-life include 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1 -Bis (t-butylperoxy) cyclohexane, n-butyl-4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane and the like. The resin-encapsulated sheet using these organic peroxides can reduce the crosslinking time relatively, and the curing process is an organic material having a half-life at 100 to 130 ° C., which is conventionally used, of 1 hour or more. Compared with the case of using a peroxide, it can be shortened to about half.

  The content of the organic peroxide is preferably 0 to 10% by mass and more preferably 0 to 5% by mass with respect to the resin constituting the resin sealing sheet. The resin-encapsulated sheet containing the organic peroxide is softened during lamination, and after the gap is filled, the decomposition and crosslinking of the organic peroxide are promoted, so the resin gel fraction increases. However, it has an advantage that the gap filling property is not hindered.

  As described above, “crosslinking” includes a method of irradiating with ionizing radiation, a method using an organic peroxide, and the like, and a method of crosslinking by irradiation with ionizing radiation is particularly preferable. For example, in the manufacturing method of the present embodiment, the crosslinking treatment can be performed by further including a crosslinking step in which the sheet (extruded product) is subjected to crosslinking treatment by irradiating with ionizing radiation. The crosslinking treatment by irradiation with ionizing radiation does not generate gas due to thermal decomposition of the organic peroxide, and therefore tends to reduce corrosion damage and oil contamination of the vacuum pump. It is also possible to eliminate adverse effects on other components such as organic peroxides that induce a crosslinking reaction and decomposition thereof, such as solar cells. In addition, the crosslinking method using an organic peroxide requires a long curing process for decomposing the organic peroxide in the lamination process and promoting the crosslinking of the resin sealing sheet. Although it is difficult to speed up production, the crosslinking method by irradiation with ionizing radiation is excellent in that it does not require a long-time curing step and can improve the productivity of the solar cell module.

  The post-treatment is not particularly limited, and for example, heat setting for dimensional stabilization, corona treatment, plasma treatment or the like may be performed, or lamination with other types of resin sheets or the like may be performed.

(resin)
The resin used in this embodiment will be described. The resin used in the present embodiment is preferably a thermoplastic resin. From the viewpoint of adhesiveness and sealing performance, the resin is selected from the group consisting of (a) (a1) an ethylene monomer, and (a2) vinyl acetate, an aliphatic unsaturated carboxylic acid, and an aliphatic unsaturated carboxylic ester. More preferably, it contains at least one selected from the group consisting of a copolymer of at least one monomer and a (b) polyolefin resin.

  In the case where the resin is a copolymer, the adhesion function with the adherend such as glass is exhibited by polarization due to the polar group of the monomer used for copolymerization, and the transparency of the resin sealing sheet is ensured. be able to. From this viewpoint, at least one resin selected from an ethylene-vinyl acetate copolymer, an ethylene-aliphatic unsaturated carboxylic acid copolymer, and an ethylene-aliphatic unsaturated carboxylic acid ester copolymer is more preferable. Furthermore, in the case of crosslinking by irradiating with ionizing radiation, the resin having a polar group is more easily crosslinked, so that the crosslinking reaction can be further promoted.

  (A) (a1) ethylene monomer, and (a2) at least one monomer selected from the group consisting of vinyl acetate, aliphatic unsaturated carboxylic acid, and aliphatic unsaturated carboxylic acid ester, Examples of the polymer obtained from this copolymer include an ethylene-vinyl acetate copolymer, an ethylene-aliphatic unsaturated carboxylic acid copolymer, and an ethylene-aliphatic unsaturated carboxylic acid ester copolymer. The copolymer may be polymerized by a known method such as a high pressure method or a melting method. When using a catalyst, the kind is not specifically limited, For example, a multi-site catalyst, a single site catalyst, etc. can be used. The bonding shape at the time of polymerization of each monomer is not particularly limited and may be a random bond or a block bond, but a random bond is preferable from the viewpoint of optical properties.

  The copolymerization ratio of (a1) ethylene monomer and (a2) vinyl acetate, aliphatic unsaturated carboxylic acid, aliphatic unsaturated carboxylic acid ester is not particularly limited, and can be determined in consideration of desired physical properties and the like. . For example, in the case of a copolymer of a polyethylene monomer and vinyl acetate, the ratio of vinyl acetate to the entire copolymer is preferably 10 to 40% by mass, more preferably 13 to 40%, from the viewpoint of optical properties, adhesiveness, and flexibility. It is 35 mass%, More preferably, it is 15-30 mass%. Further, from the viewpoint of processability of the resin-encapsulated sheet, MFR (190 ° C., 2.16 kg: hereinafter, ethylene-vinyl acetate copolymer, ethylene-aliphatic unsaturated carboxylic acid copolymer, ethylene-aliphatic unsaturated) The same conditions for the carboxylic acid ester copolymer) are preferably 0.3 to 30, more preferably 0.5 to 30, and still more preferably 0.8 to 25.

  Specific examples of the ethylene-aliphatic unsaturated carboxylic acid copolymer and the ethylene-aliphatic unsaturated carboxylic acid ester copolymer include ethylene-acrylic acid copolymer (hereinafter referred to as EAA), ethylene- Methacrylic acid copolymer (hereinafter referred to as EMAA), ethylene-acrylic acid ester (for example, ester of C1-C8 alcohol such as methyl, ethyl, propyl, butyl) copolymer, ethylene-methacrylic acid ester (For example, esters of alcohols having 1 to 8 carbon atoms such as methyl, ethyl, propyl, and butyl), and the like. These include three or more multi-component copolymers (for example, other components added) (for example, It may be a ternary or higher copolymer suitably selected from ethylene, an aliphatic unsaturated carboxylic acid and the same ester). In these copolymers, the content of the carboxylic acid or carboxylic acid ester group is not particularly limited, but usually 3 to 35% by mass is used.

  Examples of the polyolefin resin referred to in the present embodiment include, for example, an ethylene polymer or a polyethylene resin that is a copolymer of ethylene and another monomer, propylene, or a copolymer of propylene and another monomer. And a polybutene resin that is a copolymer of butene or butene and other monomers.

  Examples of the polyethylene-based resin of the present embodiment include those that include a commercially available homopolymer of ethylene having a long chain branch, or a copolymer modified with a small amount of α-olefin. . Further, modified polyethylene (for example, EVA having a vinyl acetate group content of less than 10% by mass) copolymerized with ethylene and the following comonomer capable of copolymerization of less than 10% by mass is also included. For example, polyethylene resins include low density polyethylene (LDPE), linear low density density polyethylene (LLDPE), linear very low density polyethylene (called “VLDPE”, “ULDPE”), ethylene-fat Soft polymer consisting of an aliphatic unsaturated carboxylic acid polymer, an ethylene-aliphatic unsaturated carboxylic acid ester copolymer, and an α-olefin copolymer (for example, α- having 4 to 12 carbon atoms and ethylene and / or propylene) Examples thereof include soft copolymers composed of one or more α-olefins selected from olefins or free combinations, and those having crystallinity by X-ray method of generally 30% or less). .

  The ethylene-α-olefin copolymer is generally polymerized using a catalyst called a single-site catalyst or a multi-site catalyst. Among them, a polymer polymerized by a single-site catalyst is preferable. . More preferably, a copolymer of ethylene comonomer and at least one comonomer selected from the group consisting of a butene comonomer, a hexene comonomer, and an octene comonomer is more preferable from the viewpoint of availability.

Preferred density of the polyethylene resin, from the viewpoint of cushioning properties are those in the range of 0.860~0.930g / cm ^3, more preferably 0.870~0.923g / cm ^3, more preferably 0. 870 to 0.915 g / cm ³ . Further, the cushioning property is improved as the density is lower. On the other hand, when the density is 0.930 g / cm ³ or more, even when the inner layer is used, the transparency tends to deteriorate. When using a high-density resin as an improvement in transparency, it can be improved by adding low-density polyethylene of about 30% by mass.

  From the viewpoint of the workability of the resin-encapsulated sheet, the MFR (190 ° C., 2.16 kg: hereinafter, the same conditions for the polyethylene resin) is preferably 0.5 to 30, more preferably 0.8 to 30, and further Preferably it is 1.0-25. Due to the melt tension, the surface layer is made of at least one resin selected from ethylene-vinyl acetate copolymer, ethylene-aliphatic unsaturated carboxylic acid copolymer, and ethylene-aliphatic unsaturated carboxylic acid ester copolymer. When the MFR of the inner layer adjacent to the surface layer is lower than the MFR of the surface layer from the viewpoint of sheet processing, it tends to be processed easily.

  Examples of polypropylene copolymer resins include copolymers of propylene and α-olefins such as ethylene, butene, hexene and octene, and terpolymers of propylene and ethylene and α-olefins such as butene, hexene and octene. Etc. These copolymers may be block copolymers or random copolymers, and are preferably a random copolymer of propylene and ethylene, or a random terpolymer of propylene, ethylene and butene. By mix | blending the said polypropylene resin, the hardness and waist | waist of a resin sealing sheet can be raised, or heat resistance can be raised. Polypropylene copolymer resin is a copolymer of homo-PP, propylene having a propylene content of 70% by mass or more and one or more of α-olefins (4 to 8 carbon atoms in addition to ethylene). The polymer is not only polymerized with a conventional catalyst such as a Ziegler-Natta catalyst, but also includes syndiotactic PP and isotactic PP polymerized with the aforementioned metallocene catalyst. Further, the polypropylene resin may be a finely dispersed rubber component having a high concentration of up to about 50% by mass, and at least one of them is used. The propylene content in the polypropylene copolymer resin is preferably 60 to 90% by mass. Further, a polypropylene copolymer resin is a ternary copolymer, and a propylene content is 60 to 80% by mass, an ethylene content is 10 to 30% by mass, and a butene content is 5 to 20% by mass. It is more preferable because the shrinkability is improved.

  Furthermore, the polybutene resin is particularly excellent in compatibility with the polypropylene resin in addition to the adjustment of the hardness and waist of the resin sealing sheet. Therefore, it is more preferable to use together with a polypropylene resin. The polybutene-based resin is not particularly limited. For example, the polybutene-based resin has a crystallinity of butene-1 content of 70 mol% or more and is one of other monomers (ethylene, propylene, and olefins having 5 to 8 carbon atoms). Alternatively, a polymer having a high molecular weight including a copolymer with two or more kinds is used. This is different from the liquid and waxy molecular weight, and the MFR (190 ° C., 2.16 kg: the same condition for polybutene resin) is usually 0.1 to 10. A preferable polybutene resin is a copolymer having a Vicat softening point of 40 to 100 ° C. Here, the Vicat softening point is a value measured according to JIS-K-7206-1982.

  The MFR value (230 ° C., 2.16 kgf: hereinafter, the same conditions for the polypropylene copolymer resin) measured in accordance with JIS-K-7210 of the polypropylene copolymer resin is 0.3-15. 0 is preferable, more preferably 0.5 to 12, and still more preferably 0.8 to 10.

  It is preferable that the resin sealing sheet in this Embodiment contains adhesive resin. As the adhesive resin, at least one kind selected from the group consisting of an olefin-based copolymer having a hydroxyl group, a modified polyolefin terminal-modified or graft-modified with an acidic functional group, and an ethylene copolymer containing glycidyl methacrylate. Resin. By containing these as adhesive resins, good adhesiveness and optical characteristics can be obtained.

  As the olefin constituting the olefin copolymer having a hydroxyl group, ethylene is suitable. The hydroxyl group can be obtained, for example, by saponifying an acetic acid group of an ethylene-vinyl acetate copolymer or an ethylene-vinyl acetate-acrylic acid ester copolymer and replacing it with a hydroxyl group. Specific examples of the olefin copolymer having a hydroxyl group include an ethylene-vinyl acetate copolymer part or a completely saponified product, and an ethylene-vinyl acetate-acrylic acid ester copolymer part or a completely saponified product. .

  The ratio of the hydroxyl group in the olefin-based copolymer having a hydroxyl group is preferably 0.1% by mass to 10% by mass, and more preferably 0.1% by mass to 7% by mass in the resin layer. The ratio of the hydroxyl group is the original olefin polymer resin of the olefin polymer having a hydroxyl group and VA% of this resin (copolymerization ratio of vinyl acetate (VA) in the copolymer by NMR measurement; mass). %), Its saponification degree, and the blending ratio in the resin layer. Resin to be blended when the proportion of hydroxyl group in the olefin copolymer having a hydroxyl group is 0.1% by mass or more in the resin layer and good adhesiveness tends to be ensured. Good compatibility can be secured, and the finally obtained resin-encapsulated sheet tends to be prevented from becoming clouded.

  The melting point of the olefin-based copolymer having a hydroxyl group is preferably 70 to 115 ° C., more preferably 73 to 115 ° C., from the viewpoint of ensuring good adhesiveness and sealing property (sealing property) to an object to be sealed. More preferably, it is 75-115 degreeC. Here, the melting point of the olefin copolymer is obtained by using a differential scanning calorimeter, raising the temperature of about 5 mg of resin from 0 ° C. to 200 ° C. at a rate of 20 ° C./min, and melting and holding at 200 ° C. for 5 minutes. An endothermic peak associated with melting obtained when the temperature is lowered to −50 ° C. or lower at a rate of 20 ° C./min and then increased from 0 ° C. to 200 ° C. at 20 ° C./min.

  The Vicat softening temperature of the olefin-based copolymer having a hydroxyl group is preferably 45 ° C. or higher, more preferably 47 ° C. or higher, from the viewpoint of ensuring good adhesion and sealing property (sealing property) to the object to be sealed. More preferably, it is 50 ° C. or higher. Here, the Vicat softening temperature is a value measured according to JIS K7206-1982.

  When the olefin copolymer having a hydroxyl group is a saponified ethylene-vinyl acetate copolymer, the content of vinyl acetate in the ethylene-vinyl acetate copolymer before saponification is good optical properties and adhesiveness. And from a viewpoint of obtaining a softness | flexibility, 10-40 mass% is preferable with respect to the whole copolymer, 13-35 mass% is more preferable, 15-30 mass% is more preferable.

  The saponification degree of the saponified ethylene-vinyl acetate copolymer is preferably 10 to 70%, more preferably 15 to 65%, and further preferably 20 to 60% from the viewpoint of obtaining good transparency and adhesiveness. preferable.

  Next, a saponification method will be described. For example, a method of saponifying ethylene-vinyl acetate copolymer pellets or powder in a lower alcohol such as methanol using an alkali catalyst, or using an ethylene-vinyl acetate copolymer in advance using a solvent such as toluene, xylene or hexane. Examples include a method of dissolving a coalescence and then saponifying with a small amount of alcohol and an alkali catalyst. In addition, there may be mentioned a method in which a monomer containing a functional group other than a hydroxyl group is graft-polymerized to a saponified copolymer.

  Since the saponified ethylene-vinyl acetate copolymer has a hydroxyl group in the side chain, its adhesion is improved compared to the ethylene-vinyl acetate copolymer, and plastics such as glass, acrylic and polycarbonate resins. It is useful as an adhesive for metals, fibers and the like. Moreover, transparency and adhesiveness can be controlled by adjusting the amount of hydroxyl groups (degree of saponification).

  Examples of modified polyolefins that have been end-modified or graft-modified with acidic functional groups include, for example, polyethylene resins and polypropylene resins that are end-modified with compounds having polar groups such as maleic anhydride, nitro groups, hydroxyl groups, and carboxy groups. Or what was graft-modified is mentioned. Among these, from the viewpoint of the stability of the polar group, a maleic acid-modified polyolefin that has been terminal-modified or graft-modified with maleic anhydride is preferable.

  The ethylene copolymer containing glycidyl methacrylate refers to an ethylene copolymer and an ethylene terpolymer with glycidyl methacrylate having an epoxy group as a reaction site, such as an ethylene-glycidyl methacrylate copolymer, an ethylene-glycidyl methacrylate-vinyl acetate copolymer. Examples thereof include a polymer and an ethylene-glycidyl methacrylate-methyl acrylate copolymer. Since the above compounds have high reactivity of glycidyl methacrylate, they can exhibit stable adhesion, and have a low glass transition temperature and tend to have good flexibility.

  According to the manufacturing method of the present embodiment, as described above, any resin-encapsulated sheet having a single-layer structure or a multilayer structure can be manufactured. Hereinafter, the layer component of each structure of the resin sealing sheet will be described. These structures can be appropriately selected by adjusting the number and structure of the extruders used in the film forming process described above.

[Single layer structure]
When the resin-encapsulated sheet has a single-layer structure, as described above, from the viewpoint of ensuring good transparency, flexibility, adhesion of the adherend and handleability, (a) (a1) ethylene monomer, (A2) a copolymer of at least one monomer selected from the group consisting of vinyl acetate, aliphatic unsaturated carboxylic acid and aliphatic unsaturated carboxylic acid ester, and (b) selected from the group consisting of polyolefin resin It is preferable that the layer contains at least one kind of resin.

  Further, as described above, the adhesive resin is selected from the group consisting of an olefin-based copolymer having a hydroxyl group, a modified polyolefin that is terminal-modified or graft-modified with an acidic functional group, and an ethylene copolymer containing glycidyl methacrylate. It is preferable to contain at least one kind of resin.

(Multilayer structure)
The resin-encapsulated sheet having a multilayer structure has a structure including two or more resin layers. Two layers forming both surfaces of the resin sealing sheet are referred to as “surface layers”, and the other layers are referred to as “inner layers” (in the case of three or more layers).

  In the case of a multilayer structure, at least one selected from the group consisting of an olefin-based copolymer having a hydroxyl group, a modified polyolefin terminal-modified or graft-modified with an acidic functional group, and an ethylene copolymer containing glycidyl methacrylate. It is preferable that the resin layer containing the resin of the kind as an adhesive resin is formed as a layer (at least one surface layer) that comes into contact with the object to be sealed.

  In the case of a multilayer structure, the resin constituting the inner layer is not particularly limited, and any other resin may be used in addition to the resin that can be preferably used for the surface layer described above. For the purpose of imparting other functions to the inner layer, resin materials, mixtures, additives, and the like can be appropriately selected. For example, for the purpose of newly imparting cushioning properties, a layer containing a thermoplastic elastomer may be provided as the inner layer. The inner layer here means a layer other than the surface layer described above.

  The thermoplastic elastomer refers to a material that exhibits rubber elasticity at room temperature and has thermoplasticity, and is obtained by blending a copolymer rubber and a polymer at an arbitrary weight ratio. The copolymer rubber can be present in the thermoplastic elastomer in a state such as uncrosslinked, partially crosslinked, or entirely crosslinked. Examples of the thermoplastic elastomer include olefin resins, styrene resins, vinyl chloride resins, polyester resins, polyurethane resins, chlorinated ethylene polymer resins, polyamide resins, and the like. In addition, plant-derived materials are also included. Among the above, a hydrogenated block copolymer resin, a propylene copolymer resin, and an ethylene copolymer resin that have good compatibility with the crystalline polypropylene resin and good transparency are preferable, and a hydrogenated block copolymer. A resin and a propylene-based copolymer resin are more preferable.

  As the hydrogenated block copolymer elastomer, a block copolymer of vinyl aromatic hydrocarbon and conjugated diene is preferable.

  Examples of vinyl aromatic hydrocarbons include styrene, -methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, α-methylstyrene, vinylnaphthalene, vinylanthracene, and 1,1-diphenylethylene. N, N-dimethyl-p-aminoethylstyrene, N, N-diethyl-p-aminoethylstyrene and the like, and styrene is particularly preferable. These may be used alone or in combination.

  The conjugated diene is a diolefin having a pair of conjugated double bonds, such as 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3- Examples include butadiene, 1,3-pentadiene, and 1,3-hexadiene. These may be used alone or in combination.

  As the propylene-based copolymer elastomer, a copolymer obtained from propylene and ethylene or an α-olefin having 4 to 20 carbon atoms is preferable. The ethylene or α-olefin content of 4 to 20 carbon atoms is preferably 6 to 30% by weight. Here, examples of the α-olefin having 4 to 20 carbon atoms include 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1- Examples include decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosane and the like.

  The propylene-based copolymer elastomer may be polymerized using a multisite catalyst, a single site catalyst, or any other catalyst. Furthermore, a propylene-based copolymer in which the crystal / amorphous structure (morphology) of the polymer is controlled in nano order can also be used. The ethylene copolymer elastomer may be polymerized with any of a multisite catalyst, a single site catalyst, and other catalysts. Further, an ethylene copolymer in which the crystal / amorphous structure (morphology) of the polymer is controlled in nano order can also be used. In addition to the above resins, known resins such as ionomers may be introduced as a single layer or mixed.

  The above-mentioned single-layer or multi-layer resin-encapsulated sheet has a coupling agent, an antifogging agent, a plasticizer, an antioxidant, a surfactant, a colorant, and an ultraviolet absorber as long as the original properties are not impaired. Agents, antistatic agents, crystal nucleating agents, lubricants, anti-blocking agents, inorganic fillers, crosslinking modifiers, etc. may be added. It may be added to the resin by a known method so that the effect of the additive can be exhibited even if it is added after coating or after coating.

  A coupling agent may be added for the purpose of imparting stable adhesiveness to the resin sealing sheet of the present embodiment. The amount added depends on the desired degree of adhesion and the type of adherend, but is preferably 0.01 to 5% by mass, more preferably 0.03 to 4% by mass, and still more preferably 0.05 to the resin. ˜3 mass%.

  Specific examples of the coupling agent are not particularly limited, and known ones can also be used. Examples thereof include organic silane compounds, organic silane peroxides, and organic titanate compounds. These coupling agents may be injected and mixed into the resin in the extruder, mixed and introduced into the extruder hopper, or masterbatched in advance and mixed and added. The method can be adopted. However, since it passes through an extruder, the original function may be hindered by heat or pressure in the extruder, and the amount added may need to be increased or decreased depending on the type of coupling agent. Further, the type of the coupling agent may be appropriately selected from the viewpoints of transparency of the resin, dispersion, corrosion to the extruder, and extrusion stability when mixed with the resin.

  Preferred coupling agents are [gamma] -chloropropylmethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyl-tris ([beta] -methoxyethoxy) silane, [gamma] -methacryloxypropyltrimethoxysilane, [beta]-(3,4-ethoxy). (Cyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-amino Examples thereof include those having an unsaturated group or an epoxy group such as propyltrimethoxysilane glycidoxypropyltriethoxysilane.

  In addition to the above, an ultraviolet absorber, an antioxidant, a discoloration inhibitor, and the like can be added. In particular, when it is necessary to maintain transparency and adhesiveness for a long period of time, these contents are preferably 0 to 10% by mass, more preferably 0 to 5% by mass with respect to the ethylene-based copolymer. is there. These ultraviolet absorbers, antioxidants, discoloration inhibitors and the like are 0 to 10% by mass, preferably 0 to 5% by mass with respect to the resin constituting the resin layer to be blended.

  The kind of additive is not specifically limited, For example, you may add a well-known ultraviolet absorber, antioxidant, discoloration inhibitor, etc. Preferred UV absorbers include 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-n-5-sulfobenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4, Examples include 4'-dimethoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone. Preferable antioxidants include phenol, sulfur, phosphorus, amine, hindered phenol, hindered amine, hydrazine and the like.

  As for the thickness of the resin sealing sheet of this Embodiment, 50 micrometers-1500 micrometers are preferable normally. More preferably, it is a thin region of 100 μm to 1000 μm, and more preferably 150 μm to 800 μm. By setting it to 50 μm or more, the cushioning property and workability of the resin-encapsulated sheet are improved. Productivity and adhesiveness become favorable by setting it as 1500 micrometers or less.

  When the resin encapsulating sheet of the present embodiment is used to seal steps such as power generation elements and wirings without gaps, the thickness of the surface layer may be affected by the cross-linked state of the surface layer. When the degree of cross-linking of the surface layer is high, the surface layer is preferably thin. On the other hand, in order to hold the crystalline silicon cell and the like firmly and stably, a certain thickness is required, and the preferred thickness of the surface layer is 10 to 150 μm, more preferably 15 to 140 μm, and still more preferably 20 to 120 μm.

  The resin-encapsulated sheet obtained by the manufacturing method of the present embodiment also has a feature that the residual stress is small and shrinkage hardly occurs as compared with the resin-encapsulated sheet obtained by the conventional method. The shrinkage ratio of the resin sealing sheet is preferably 30% or less, more preferably 25% or less, still more preferably 10% or less, and particularly preferably 0% at a thickness of 450 μm. Further, at a thickness of 600 μm, 10% or less is preferable, 5% or less is more preferable, 3% or less is further preferable, and substantially 0% is particularly preferable. Here, the shrinkage rate is a value obtained by immersing the resin-encapsulated sheet in warm water at 70 ° C. for 5 minutes and then measuring a change in the length of the sheet in the machine flow direction with a ruler.

<Solar cell module>
FIG. 7 is a schematic cross-sectional view of one aspect of the solar cell module of the present embodiment. That is, the solar cell module 1 of the present embodiment includes a translucent insulating substrate 2, a back sheet 3, a power generation element 4 disposed between the translucent insulating substrate 2 and the back sheet 3, and the translucent substrate. And a resin sealing sheet 5 for sealing the power generating element 4 between the light insulating substrate 2 and the back sheet 3.

  The material etc. of the translucent insulated substrate 2 are not specifically limited, A well-known thing can be used. Here, the translucent insulating substrate 2 may be a base material having at least light transmissivity. In particular, from the viewpoint of ensuring long-term reliability during use of the solar cell module, a material having excellent mechanical strength such as weather resistance, water repellency, and impact resistance is preferable.

  Specific examples include a resin film made of a polyester resin, a fluororesin, an acrylic resin, a cyclic polyolefin, an ethylene-vinyl acetate copolymer, a glass substrate, and the like. Among these, a glass substrate, polymethyl methacrylate (PMMA), and cyclic polyolefin (COP) are preferable from the viewpoints of light transmittance, weather resistance, impact resistance, and cost balance.

  In particular, a fluororesin having excellent weather resistance is also preferably used. Specifically, tetrafluoroethylene-ethylene copolymer (ETFE), polyvinyl fluoride resin (PVF), polyvinylidene fluoride resin (PVDF), polytetrafluoroethylene resin (TFE), tetrafluoroethylene-6 Examples thereof include a fluorinated propylene copolymer (FEP) and a poly (trifluorotrifluoroethylene resin) (CTFE). Polyvinylidene fluoride resin is preferable from the viewpoint of weather resistance, but tetrafluoroethylene-ethylene copolymer is preferable from the viewpoint of achieving both weather resistance and mechanical strength. Moreover, it is preferable to perform a corona treatment and a plasma treatment on the light-transmitting insulating substrate in order to improve adhesiveness with a material constituting another layer such as a resin sealing material. Moreover, in order to improve mechanical strength, it is also possible to use a sheet that has been subjected to a stretching treatment, for example, a biaxially stretched polypropylene sheet.

  When a glass substrate is used as the translucent insulating substrate 2, the total light transmittance of light having a wavelength of 350 to 1400 nm is preferably 80% or more, more preferably 90% or more. As such a glass substrate, it is common to use white plate glass with little absorption in the infrared part, but even blue plate glass has little influence on the output characteristics of the solar cell module if the thickness is 3 mm or less. Further, tempered glass can be obtained by heat treatment to increase the mechanical strength of the glass substrate, but float plate glass without heat treatment may be used. Further, an antireflection coating may be applied to the light receiving surface side of the glass substrate in order to suppress reflection.

  The back sheet 3 is not particularly limited and is located on the outermost layer of the solar cell module, and therefore, various characteristics such as weather resistance and mechanical strength are required in the same manner as the above-described translucent insulating substrate 2. Therefore, the back sheet 3 may be made of the same material as that of the translucent insulating substrate 2. That is, the above-described various materials that can be used in the translucent insulating substrate 2 can also be used in the backsheet 3. In particular, a polyester resin and a glass substrate can be preferably used, and among these, a polyethylene terephthalate resin (PET) is more preferable from the viewpoint of weather resistance and cost.

  Since the backsheet 3 does not assume the passage of sunlight, the transparency (light transmission) required for the light-transmitting insulating substrate 2 is not necessarily required. Therefore, in order to increase the mechanical strength of the solar cell module 1 or to prevent distortion and warpage due to temperature change, a reinforcing plate may be attached. For example, a steel plate, a plastic plate, an FRP (glass fiber reinforced plastic) plate or the like can be preferably used.

  The back sheet 3 may have a multilayer structure composed of two or more layers. Examples of the multilayer structure include a structure in which one or more layers of the same component are laminated on both sides of the central layer so as to be symmetrically arranged with respect to the central layer. As what has such a structure, PET / alumina vapor deposition PET / PET, PVF (brand name: Tedlar) / PET / PVF, PET / AL foil / PET etc. are mentioned, for example.

  The power generating element 4 is not particularly limited as long as it can generate power using the photovoltaic effect of a semiconductor or the like. For example, silicon (single crystal, polycrystalline, amorphous), compound semiconductor ( 3-5 group, 2-6 group, others) etc. can be used. Among these, polycrystalline silicon is preferable from the viewpoint of balance between power generation performance and cost.

  Hereinafter, the present invention will be described in detail based on Examples and Comparative Examples, but the present invention is not limited to the following Examples. The evaluation methods performed in this example are as follows.

<Upward film-forming property with annular die>
The resin was melt extruded in a tube shape upward from a multilayer annular die (diameter: 250 mm, slit thickness: 1 mm) connected to three extruders (surface layer, inner layer, innermost layer). While taking this, it was crushed by a stabilizer. The crushed extrudate was sealed with a pair of nip rolls to form a tube. Air was introduced into the obtained tube, and it was rapidly cooled and solidified using an air cooling ring so as to obtain a desired sheet thickness and sheet folding width, and the tube was crushed and integrated, and wound on a roll. Thereby, a resin sheet having a five-layer structure of surface layer / inner layer / innermost layer / inner layer / surface layer was obtained.

<Downward film-forming property with annular die>
The resin was melt-extruded downward in a tubular shape from a multilayer annular die (diameter: 250 mm, slit thickness: 1 mm) connected to three extruders (surface layer, inner layer, innermost layer). While taking this, it was crushed by a stabilizer. The crushed extrudate was sealed with a pair of nip rolls to form a tube. Air was introduced into the obtained tube, and it was rapidly cooled and solidified using a water-cooling ring so as to obtain a desired sheet thickness and sheet folding width, and the tube was crushed and integrated to be wound on a roll. Thereby, a resin sheet having a five-layer structure of surface layer / inner layer / innermost layer / inner layer / surface layer was obtained.

<Irradiation treatment>
Using an electron beam irradiation apparatus (manufactured by Nissin High Voltage Co., Ltd.) of EPS-300 or EPS-800, electron beam irradiation was performed on the resin sheet obtained with the acceleration voltage and irradiation density shown in the table.

<Gel fraction>
A sample was extracted for 12 hours in boiling p-xylene, and the ratio of the insoluble portion was expressed by the following formula, which was used as a measure of the degree of crosslinking of the resin sheet.
Gel fraction (mass%) = (sample weight after extraction / sample weight before extraction) × 100
In addition, the gel fraction of the surface layer in the case of the multilayer structure is obtained by preparing a single-layer resin sheet having the same thickness as the surface layer and measuring the resin sheet subjected to the electric wire irradiation treatment by the above method. The gel fraction of the surface layer was used.

<Heat shrinkage>
A resin sheet was cut into a 10 cm square and used as a sample. This sample was immersed in warm water heated to 70 ° C. for 5 minutes in a warm water bath, and then the length (change) in the machine direction of the sheet was measured with a ruler to calculate the shrinkage rate.

<Production of solar cell module>
Using the obtained resin sealing sheet, a solar cell module was created and its physical properties were evaluated. A solar cell module is obtained by laminating a glass plate for a solar cell / resin sheet / power generation part / resin sheet / back sheet in that order and vacuum laminating under the conditions shown in each table using an LM50 type vacuum laminator (NPC). Manufactured. About the obtained solar cell module, the sealing result (lamination result) was evaluated by the external appearance. Those in which the step of the cell was not completely sealed, and those in which the positional deviation of the cell was confirmed before and after lamination were judged as bad, and those having no problem in appearance were judged good.

The materials used in this example are as follows.
<Solar cell glass plate>
AGC, glass for solar cell, white glass with embossed thickness 3.2mm
<Back sheet>
Mitsubishi Aluminum Packaging Back Sheet Polyvinyl fluoride (trade name: Tedlar, 40 μm) / PET (250 μm) / Polyvinyl fluoride (40 μm) 3 layer structure

<Vertical 8585 test>
The vertical 8585 test refers to a test in which a solar cell module manufactured by the above method is vertically set and kept in a constant temperature and humidity chamber at 85 ° C. and a relative humidity of 85% for 1000 hours. After this test, the sealing state of the cell was evaluated by appearance. Compared with the case immediately after the production, those in which the positional deviation of the cells due to the melting and flow of the resin was confirmed after the test were judged as bad, and those without the appearance change were judged as good.

  The production conditions and evaluation results of each example and each comparative example are shown in Tables 1 to 4.

<Examples 1 to 12>
Each of the three extruders was charged with the resins listed in Tables 1 to 3, and melted and extruded into tubes in the upward or downward direction from a multilayer annular die connected to the extruders, and crushed by a stabilizer. After putting air into a resin tube formed by sealing with a nip roll, the tube was crushed and integrated, and wound on a roll. This resin sheet was embossed and satin processed by the above method under the conditions described in each table, then subjected to electron beam treatment to obtain a resin encapsulated sheet, which was subjected to various evaluations.

  In each Example, even if it was resin with high blocking property, the resin sealing sheet was stably manufactured using the cyclic die | dye. And from the result of each table | surface, according to the manufacturing method of each Example, while being excellent in adhesiveness and a creep-proof characteristic, it was confirmed that the resin sealing sheet with a low heat shrinkage rate can be manufactured efficiently.

<Comparative Examples 1 and 2>
The evaluation was carried out by the same evaluation method as in Example 6 except that the film forming method was the T-die film forming method and the calendar film forming method. The results are shown in Table 4. In Comparative Example 1, a film was formed by a T-die film forming method.
In Comparative Example 1, the sheet could be formed, but the heat shrinkage rate was large, and the cell displacement was confirmed when the solar cell module was formed.
In Comparative Example 2, the film was formed by a calendar film forming method. Since Comparative Example 2 was a calendar film forming method, a multilayer structure sheet could not be formed.

  The method for producing a resin encapsulating sheet according to the present invention has industrial applicability as a method for producing a sealing material for sealing various members such as a power generating element constituting a solar cell module.

DESCRIPTION OF SYMBOLS 1 Solar cell module 2 Translucent insulated substrate 3 Back sheet 4 Power generation element 5 Resin sealing sheet 10 Annular die 12 Extruder 14 Polymer pipe 16 Stabilizing plate 18 Nip roll 20, 22 Guide roll 24 Pinch roll 26 Preheating roll 28 Heating part 30 Shaping roll (pear texture roll, emboss roll, emboss roll with pear texture),
32 Backup roll S Resin sheet

Claims (12)

A film forming step of melt-extruding resin from an annular die to form a cylindrical shape;
A molding step for at least making a flat extrudate by crushing the side surface of the cylindrical extrudate obtained by the film forming step;
The manufacturing method of the resin sealing sheet containing this.   The method for producing a resin-encapsulated sheet according to claim 1, wherein, in the film-forming step, the cylindrical extrudate is formed by an inflation method in which the resin is melt-extruded from the annular die in an upward direction or a downward direction.   The manufacturing method of the resin sealing sheet of Claim 1 or 2 further including the cooling process which cools and solidifies the extrudate melt-extruded from the said cyclic | annular die by water cooling or air cooling.   The manufacturing method of the resin sealing sheet as described in any one of Claims 1-3 whose said cyclic | annular die is a multilayer cyclic | annular die.   In the molding step, after the side surfaces of the cylindrical extrudate are overlapped with a stabilizer, the side surfaces of the extrudate are crushed by a nip roll to form a flat extrudate. The manufacturing method of the resin sealing sheet as described in any one.   The method for producing a resin-encapsulated sheet according to any one of claims 1 to 5, further comprising a step of embossing and / or satin finishing after the flat extrudate is softened.   The method for producing a resin-encapsulated sheet according to claim 6, wherein the softening is performed by at least one method selected from the group consisting of infrared heating, hot air heating, and a heating roll.   The manufacturing method of the resin sealing sheet as described in any one of Claims 1-7 which further includes the process of performing the crosslinking process by ionizing radiation irradiation to the said flat extrudate.   The resin comprises (a) (a1) ethylene monomer and (a2) at least one monomer selected from the group consisting of vinyl acetate, aliphatic unsaturated carboxylic acid and aliphatic unsaturated carboxylic acid ester. The manufacturing method of the resin sealing sheet as described in any one of Claims 1-8 which is resin containing at least 1 or more types chosen from the group which consists of a polymer and (b) polyolefin-type resin. The resin sealing sheet has a multilayer structure, and the surface layer of the resin sealing sheet contains an olefin resin having a hydroxyl group, a modified polyolefin resin terminal-modified or graft-modified with an acidic functional group, and glycidyl methacrylate. The manufacturing method of the resin sealing sheet as described in any one of Claims 1-9 containing the at least 1 or more types of adhesive resin selected from the group which consists of an ethylene copolymer.   The resin sealing sheet manufactured by the method as described in any one of Claims 1-10. A translucent insulating substrate;
A backsheet,
A power generating element disposed between the translucent insulating substrate and the backsheet;
The resin sealing sheet according to claim 11, wherein the power generating element is sealed between the translucent insulating substrate and the back sheet.
A solar cell module comprising: