JP2015099811A - Front plate for solar cell panel, method for manufacturing the same, and solar cell panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a front plate for a solar cell panel, capable of suppressing the occurrence of a PID phenomenon and also excellent in adhesion between a sealing material and a resin layer; a method for manufacturing the front plate for a solar cell panel; and a solar cell panel using the front plate.SOLUTION: A front plate for a solar cell panel has a glass layer and a resin layer in contact with the glass layer. The resin layer is a layer comprising the following resin (A1) or a mixture of the following resin (A2) and the following resin (A3). Resin (A1): a resin containing a hydroxyl group, a carboxyl group, and a -(COO)Agroup (where, A represents at least one cation selected from the group consisting of an alkaline earth metal ion and an ammonium ion, and n represents a valence of A) (A2): a resin including a hydroxyl group (A3): a resin containing a carboxyl group, and a -(COO)Agroup (where, A represents at least one cation selected from the group consisting of an alkaline earth metal ion and an ammonium ion, and n represents a valence of A).

Description

  The present invention relates to a front panel for a solar cell panel, a manufacturing method thereof, and a solar cell panel using the front panel.

  The solar battery panel is, for example, a front plate made of a transparent plate-like material such as a glass substrate, a front surface side sealing material, a solar battery cell made of a silicon power generation element, a back surface side sealing material, and a back sheet. Are laminated in this order, and the front side sealing material and the back side sealing material are bonded and integrated, and the peripheral portions of the front plate and the back sheet are fixed using a frame.

The solar cell panel having the above structure is installed outdoors and used for a long time in an environment exposed to wind and rain. With the recent spread of solar power generation, the scale of power generation systems such as megasolars is increasing, and there is a movement to increase the system voltage for the purpose of reducing transmission loss. As the system voltage rises, in the solar battery panel, the potential difference between the front plate and the cell is large, and power generation during the day is maintained in a state where a high voltage is applied.
In the solar cell panel used in such a state, it has been reported that a PID (abbreviation of Potential Induced Degradation) phenomenon in which the output is greatly reduced and the characteristics are deteriorated. The PID phenomenon is considered to occur due to the interaction between each member such as a glass substrate on the surface of the solar cell panel and a cell, a back sheet, etc., when a high voltage is applied to the solar cell panel under high temperature and high humidity conditions.

  In patent document 1, in order to suppress generation | occurrence | production of a PID phenomenon, the sealing material containing the ethylene-alpha-olefin copolymer which has a specific density is described. Patent Document 2 describes a sealing material containing a specific ethylene-α-olefin-nonconjugated polyene copolymer.

JP 2012-238857 A WO2012 / 070245

However, with the sealing materials described in Patent Documents 1 and 2, it is difficult to sufficiently suppress the occurrence of the PID phenomenon.
In view of the above-described problems, the present invention can suppress the occurrence of the PID phenomenon, and has a front panel for a solar cell panel having excellent adhesion between a sealing material and a resin layer, a method for manufacturing the same, and the front panel. It aims at providing the solar cell panel using this.

This invention is a front panel for solar cell panels which has a glass layer and the resin layer which contact | abuts to this glass layer, Comprising: The said resin layer is a layer containing the following resin (A1), or the following resin (A2) It is related with the solar cell panel using the front plate for solar cell panels which is a layer containing the mixture of and the following resin (A3), its manufacturing method, and the said front plate.
Resin (A1): hydroxyl group, carboxyl group,-(COO) _n A ⁿ group (wherein A is at least one cation selected from the group consisting of alkaline earth metal ions and ammonium ions, and n is Resin (A2): Resin containing hydroxyl group Resin (A3): Carboxyl group and — (COO) _n ^An group (wherein A is an alkaline earth metal ion, A resin containing at least one cation selected from the group consisting of ammonium ions, and n is the valence of A)

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to suppress the generation | occurrence | production of a PID phenomenon, and the front plate for solar cell panels excellent in the adhesiveness of a sealing material and a resin layer, its manufacturing method, and the said front plate are used. It is possible to provide a solar cell panel.

Sectional drawing (schematic diagram) of one Embodiment of the solar cell panel which concerns on this invention.

[Solar panel front plate]
The solar cell panel front plate according to the present invention has a glass layer and a resin layer in contact with the glass layer.
<Glass layer>
A glass substrate that transmits sunlight is used for the glass layer. Examples of the glass substrate material include soda lime glass, alkali-free glass, tempered glass, and sapphire glass. From the viewpoint of improving the interfacial adhesive force with the resin composition layer described later, the surface of the glass substrate may be surface-treated with, for example, a silane coupling agent. Further, on the light-receiving surface side of the glass substrate (the surface opposite to the surface on which a resin layer described later is provided), antireflection treatment, scratch prevention treatment, and dirt using silicon oxide fine particles described in JP2011-148288A It is preferable that the prevention process, the snow sliding process, etc. are performed.
The thickness of the glass layer is preferably from 0.01 mm to 6 mm, more preferably from 0.5 mm to 4 mm, and still more preferably from 1.5 mm to 3.5 mm.

<Resin layer>
The resin layer is a layer provided in contact with the glass layer, and is preferably provided on the surface opposite to the light receiving surface side of the glass substrate. The resin layer is formed by applying a glass substrate to a coating liquid containing a resin described later and heat-treating it. Two or more resin layers may be used. In that case, a coating liquid containing the same or different resin components is used.
The thickness of the resin layer is preferably 0.05 μm or more and 10 μm or less, more preferably 0.1 μm or more and 7 μm or less, and further preferably 0.5 μm or more and 5 μm or less.

(Resin component)
As the resin forming the resin layer, one of two kinds of resins can be mentioned. The first is a case where the following resin (A1) is used alone, and the second is a case where a mixture of the following resin (A2) and the following resin (A3) is used.
Resin (A1): hydroxyl group, carboxyl group,-(COO) _n A ⁿ group (wherein A is at least one cation selected from the group consisting of alkaline earth metal ions and ammonium ions, and n is Resin (A2): Resin containing hydroxyl group Resin (A3): Carboxyl group and — (COO) _n ^An group (wherein A is an alkaline earth metal ion, A resin containing at least one cation selected from the group consisting of ammonium ions, and n is the valence of A)

(Resin (A1))
In the resin (A1), examples of the alkaline earth metal ion that is a cation forming a — (COO) _n ^An group include beryllium ion, calcium ion, magnesium ion, strontium ion, and barium ion. Of these, magnesium ions and calcium ions are preferred.

As the resin (A1), vinyl alcohol-acrylic acid-calcium acrylate, vinyl alcohol-methacrylic acid-calcium acrylate, vinyl alcohol-acrylic acid-ammonium acrylate, vinyl alcohol-methacrylic acid-ammonium methacrylate .
The resin (A1) is obtained by neutralizing a part of the carboxyl group of the resin containing a hydroxyl group and a carboxyl group with at least one cation selected from the group consisting of alkaline earth metal ions and ammonium ions. May be. Examples of the resin containing a hydroxyl group and a carboxyl group include resins such as vinyl alcohol-acrylic acid copolymer and vinyl alcohol-methacrylic acid copolymer.

The resin (A1) is preferably produced by the following method (1) to method (3).
Method (1): Method of adding an alkaline earth metal ion donor or an ammonium ion donor compound to a solution containing a hydroxyl group and carboxyl group-containing resin and a liquid medium Method (2): containing a hydroxyl group and a carboxyl group Method of exchanging solution containing resin and liquid medium with alkaline earth metal ion or ammonium ion (3): hydroxyl group and carboxyl group completely neutralized with alkaline earth metal ion or ammonium ion Method for exchanging solution containing resin and liquid medium with hydrogen ion

In the above method (1), examples of the alkaline earth metal ion donating compound include hydroxides and chlorides of alkaline earth metal ions. Specific examples include calcium hydroxide, magnesium hydroxide, calcium chloride, and magnesium chloride. These may be used alone or in combination of two or more.
Examples of the ammonium ion donor include inorganic ammonium salts such as ammonium chloride, ammonium phosphate, ammonium perchlorate, and ammonium carbonate, organic ammonium salts such as ammonium acetate, and aqueous ammonia. These may be used alone or in combination of two or more.

  Examples of the liquid medium preferably used in the method (1) include a liquid medium that swells and cleaves an inorganic layered compound described later.

In the above method (2), as a method for ion exchange of a resin such as vinyl alcohol-acrylic acid copolymer or vinyl alcohol-methacrylic acid copolymer with alkaline earth metal ions or ammonium ions, for example, A method of removing a solution containing a resin and a liquid medium by mixing and stirring an ion exchange resin having alkaline earth metal ions or ammonium ions, and filtering or centrifuging the ion exchange resin residue (2 ') Or a method (2 ″) of passing the solution through a column packed with an ion exchange resin.
In the above method (1), the ratio of the solution and the ion exchange resin, the stirring time, the stirring speed, and the temperature of the solution are adjusted. In the method (2), the column length, the liquid passing speed, and the aqueous solution temperature are adjusted. The desired neutralization degree can be obtained.

  Examples of the liquid medium preferably used in the method (2) include a liquid medium that swells and cleaves an inorganic layered compound described later.

In the method (3), as a method of exchanging a solution containing a resin and a liquid medium, which has been completely neutralized with alkaline earth metal ions or ammonium ions, with hydrogen ions, for example, the solution and hydrogen ions are included. A method of mixing and stirring the ion exchange resin and removing the ion exchange resin residue by filtration or centrifugation (3 ′), or a method of passing the solution through a column packed with the ion exchange resin (3 ″) and the like.
In the above method (3 ′), the ratio of the solution and the ion exchange resin, the stirring time, the stirring speed, and the temperature of the solution are adjusted. In the method (3 ″), the column length, the liquid passing speed, and the aqueous solution temperature are adjusted. By doing, it can be set as a desired neutralization degree.

  Examples of the liquid medium preferably used in the method (3) include a liquid medium that swells and cleaves an inorganic layered compound described later.

When the resin (A1) is produced by the method described in the above methods (1) to (3), the degree of neutralization of the resin (A1) depends on the adhesion between the resin layer and the sealing material layer and the occurrence of the PID phenomenon. From the viewpoint of suppression, it is preferably 1% or more and 80% or less, and more preferably 5% or more and 70% or less.
The degree of neutralization is a value reflecting the amount of carboxylate ions contained in the carboxyl group and-(COO) _n ^An group, and is calculated by the following equation.
Degree of neutralization = (A / B) × 100
A: Number of moles of carboxyl groups neutralized in 1 g of resin (A1) to form a salt B: Total number of moles of carboxyl groups neutralized in 1 g of resin (A1) to form a salt

In the above methods (1) to (3), the amount of the hydroxyl group of the resin (A1) in the liquid medium is 30 from the viewpoint of suppressing the adhesion between the resin layer and the sealing material layer and the occurrence of the PID phenomenon. It is preferably from mol% to 95 mol%, more preferably from 40 mol% to 80 mol%.
The amount of carboxylate ions contained in the carboxyl group and-(COO) _n ^An group is 5 mol from the viewpoint of suppressing the adhesion between the resin layer and the sealing material layer and the occurrence of the PID phenomenon. % To 70 mol%, more preferably 20 mol% to 60 mol% (provided that the amount of the hydroxyl group and the carboxyl group and — (COO) _n ^An group) The sum of the amount of carboxylate ions and the amount of the substance is 100 mol%).

Moreover, the ratio (Y / X) of the substance amount (X) of the carboxylate ion contained in the-(COO) _n ^An group and the substance amount (Y) of the carboxylate ion contained in the carboxyl group is expressed as PID From the viewpoint of suppressing the occurrence of the phenomenon, it is preferably 20/80 or more and 99/1 or less, and more preferably 30/70 or more and 90/10 or less.

The substance amount of the hydroxyl group, the carboxyl group, and the substance amount of the carboxylate ion contained in the-(COO) _n ^An group are adjusted by a monomer containing a hydroxyl group, a monomer containing a carboxyl group, and-(COO) _n ^An group. By adjusting the blending ratio with the monomer containing, and performing polymerization, a desired substance amount ratio can be obtained.

The substance amount of the hydroxyl group and carboxylate ion can be determined by a known NMR method, IR method or the like. For example if the IR method, a hydroxyl group, a carboxyl group, - (COO) molar ratio of _n A ⁿ groups using known samples to obtain the calibration curve can be calculated.

Moreover, when a solar cell panel is used under high voltage, from the viewpoint of suppressing the occurrence of the PID phenomenon, the weight of the hydroxyl group, carboxyl group, and-(COO) _n A ⁿ group contained in the resin (A1) in the liquid medium. The total weight of the carboxylate ions is preferably 30% by weight to 60% by weight, more preferably 35% by weight to 55% by weight. The total of the weight of the hydroxyl group, the weight of the carboxyl group, and the weight of the-(COO) _n ^An group is a value when the weight of the resin (A1) is 100% by weight.

  The measurement of the weight of the hydroxyl group and the weight of the carboxylate ion can be obtained by a known NMR method, IR method, etc., as with the substance amount. For example, in the case of the IR method, a calibration curve can be obtained and calculated for a polyol polymer having a known number of polyol units and a polycarboxylic acid polymer having a known number of polycarboxylic acid units.

When the cation is an alkaline earth metal ion, the weight of the cation can be measured using a capillary electrophoresis apparatus or an inductively coupled plasma emission spectrometer. Here, when measurement is performed using an inductively coupled plasma optical emission spectrometer, the obtained alkaline earth metal concentration is defined as the alkaline earth metal ion concentration. When the cation is an ammonium ion, the cation can be calculated from the number of moles of the neutralized carboxyl group.
Moreover, as a method of adjusting the weight of a cation, it can adjust by the method similar to the method of adjusting the said neutralization degree.

(Resin (A2))
Examples of the resin (A2) include polyvinyl alcohol and polysaccharides. Among these, it can be dissolved in an aqueous liquid medium, is easy to handle, and is a polyvinyl alcohol from the viewpoint of the effect of suppressing the output decrease when the solar cell panel is used under a high voltage. preferable.

  Here, polyvinyl alcohol refers to a polymer having a monomer unit derived from vinyl alcohol as a main component. Examples of such “polyvinyl alcohol” include a polymer obtained by hydrolyzing the acetate portion of a vinyl acetate polymer (exactly a copolymer of vinyl alcohol and vinyl acetate), and a trifluorovinyl acetate polymer. And polymers obtained by hydrolyzing vinyl formate polymer, vinyl pivalate polymer, tert-butyl vinyl ether polymer, trimethylsilyl vinyl ether polymer and the like. The degree of “saponification” in polyvinyl alcohol is preferably 70 mol% or more, more preferably 85 mol% or more, and even more preferably 98% mol or more of a so-called completely saponified product. The degree of polymerization is more preferably from 100 to 5000, and more preferably from 200 to 3000. The polyvinyl alcohol may have an ethylene unit in the main chain.

  In addition, polyvinyl alcohol derivatives having a functional group other than a hydroxyl group can also be used as the polyvinyl alcohol. Examples of the functional group other than a hydroxyl group include an amino group, a thiol group, a carboxyl group, a sulfone group, a phosphoric acid group, a carboxylate group, and a sulfonic acid. Illustrative examples include ionic groups, phosphate ion groups, ammonium groups, phosphonium groups, silyl groups, siloxane groups, alkyl groups, allyl groups, fluoroalkyl groups, alkoxy groups, carbonyl groups, and halogen groups. A part of hydroxyl groups in polyvinyl alcohol may be replaced with one or more of these functional groups.

  Polysaccharides are biopolymers synthesized in biological systems by polycondensation of various monosaccharides, and here include those chemically modified based on them. Examples thereof include cellulose and cellulose derivatives such as hydroxymethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, amylose, amylopectin, pullulan, curdlan, xanthan, chitin, chitosan and the like.

The weight average molecular weight of the hydroxyl group-containing resin (A2) is preferably in the range of 1000 to 500,000, more preferably 2000 to 300,000.
The weight average molecular weight of the resin (A3) containing a carboxyl group is preferably in the range of 2,000 to 10,000,000, and more preferably 10,000 to 3,000,000.

(Resin (A3))
Resin (A3) is a carboxyl group and-(COO) _n A ⁿ group (wherein A is at least one cation selected from the group consisting of alkaline earth metal ions and ammonium ions, and n is the value of A Number). Examples of the alkali metal earth ions that are cations include the same ions as in the resin (A1). Of these, magnesium ions and calcium ions are preferred.

Examples of the resin (A3) include calcium polyacrylate, calcium polymethacrylate, ammonium polyacrylate, ammonium polymethacrylate, magnesium polyacrylate, magnesium polymethacrylate, and the like.
The resin (A3) may be a resin obtained by neutralizing a part of the carboxyl group of the resin containing a carboxyl group with at least one cation selected from the group consisting of alkaline earth metal ions and ammonium ions. Good. Examples of the resin containing a carboxyl group include resins such as polyacrylic acid, polymethacrylic acid, and acrylic acid-methacrylic acid copolymer.

The resin (A3) is preferably produced by the following method (1) to method (3).
Method (1): Method of adding alkaline earth metal ion donor or ammonium ion donor compound to a solution containing a carboxyl group-containing resin, resin (2), and liquid medium Method (2): carboxyl group Method of ion exchange of solution containing resin containing resin, resin (2), and liquid medium with alkaline earth metal ions or ammonium ions (3): Complete neutralization with alkaline earth metal ions or ammonium ions Of exchanging a solution containing a carboxyl group-containing resin, resin (2), and liquid medium with hydrogen ions

In the method (1), examples of the alkaline earth metal ion donating compound include compounds similar to the alkaline earth metal ion hydroxides and chlorides mentioned in the production of the resin (A1). These may be used alone or in combination of two or more.
Moreover, as said ammonium ion donor, the compound similar to the compound quoted in manufacture of resin (A1) is mentioned. These may be used alone or in combination of two or more.

  When the method (1) is used, a desired degree of neutralization can be achieved by adjusting the amount ratio of a resin such as polyacrylic acid or polymethacrylic acid and the above-mentioned alkaline earth metal ion donor or ammonium ion donor compound. It can be.

  Examples of the liquid medium preferably used in the method (1) include the same liquid medium as that mentioned in the production of the resin (A1).

In the method (2), as a method for ion-exchange of resins such as polyacrylic acid and polymethacrylic acid with alkaline earth metal ions or ammonium ions, for example, a solution containing the resin and a liquid medium; A method (2 ′) in which an ion exchange resin having alkaline earth metal ions or ammonium ions is mixed and stirred and the residue of the ion exchange resin is removed by filtration or centrifugation (2 ′), or a column packed with the ion exchange resin Examples thereof include a method (2 ″) of passing the solution.
In the above method (1), the ratio of the solution and the ion exchange resin, the stirring time, the stirring speed, and the temperature of the solution are adjusted. In the method (2), the column length, the liquid passing speed, and the aqueous solution temperature are adjusted. The desired neutralization degree can be obtained.

  Examples of the liquid medium preferably used in the method (2) include the same liquid medium as that described in the production of the resin (A1).

In the method (3), as a method of exchanging a solution containing a resin and a liquid medium, which has been completely neutralized with alkaline earth metal ions or ammonium ions, with hydrogen ions, for example, the solution and hydrogen ions are included. A method of mixing and stirring the ion exchange resin and removing the ion exchange resin residue by filtration or centrifugation (3 ′), or a method of passing the solution through a column packed with the ion exchange resin (3 ″) and the like.
In the above method (3 ′), the ratio of the solution and the ion exchange resin, the stirring time, the stirring speed, and the temperature of the solution are adjusted. In the method (3 ″), the column length, the liquid passing speed, and the aqueous solution temperature are adjusted. By doing, it can be set as a desired neutralization degree.

  Examples of the liquid medium preferably used in the method (3) include the same liquid medium as that described in the production of the resin (A1).

When the resin (A3) is produced by the method described in the above methods (1) to (3), the degree of neutralization of the resin (A3) depends on the adhesion between the resin layer and the sealing material layer and the occurrence of the PID phenomenon. From the viewpoint of suppressing the above, it is preferably 1% or more and 80% or less, and more preferably 5% or more and 70% or less. The degree of neutralization is a value reflecting the amount of carboxylate ions contained in the carboxyl group and-(COO) _n ^An group, and is calculated by the following equation.
Degree of neutralization = (A / B) × 100
A: Number of moles of carboxyl groups neutralized in 1 g of resin (A3) to form a salt B: Total number of moles of carboxyl groups neutralized in 1 g of resin (A3) to form a salt

In the above methods (1) to (3), the amount of the carboxylate ion in the carboxyl group of the resin (A3) in the liquid medium is determined by the improvement in the adhesion between the resin layer and the sealing material layer and the PID phenomenon. From the viewpoint of suppressing generation, it is preferably 20 mol% or more and 99 mol% or less, and more preferably 30 mol% or more and 95 mol% or less. Further, the amount of the carboxylate ion contained in the-(COO) _n ^An group is 1 mol% from the viewpoint of improving the adhesion between the resin layer and the sealing material layer and suppressing the occurrence of the PID phenomenon. It is preferably 80 mol% or less, more preferably 5 mol% or more and 70 mol% or less (provided that the amount of the carboxyl group substance and the carboxylate ion substance in the — (COO) _n ^An group) The total amount is 100 mol%).

The carboxyl group - _(COO) ^{n A} n group and method of adjusting the amount of substance of the carboxylate ion contained in the resin (A3) is a carboxyl group in one molecule - the _(COO) ^{n A} n group In the case of the resin containing, by adjusting the blending ratio of the monomer containing a carboxyl group and the monomer containing a — (COO) _n ^An group, polymerization can be performed to obtain a desired substance amount ratio.

The amount of the carboxyl group and-(COO) _n A ⁿ group can be calculated by the same method as in the case of the resin (A1).

Moreover, when a solar cell panel is used under a high voltage, from the viewpoint of suppressing the occurrence of the PID phenomenon, a carboxyl group contained in the resin (A3) in the liquid medium and a carboxylate in the-(COO) _n ^An group. The total weight of ions is preferably 30% by weight to 60% by weight, and more preferably 35% by weight to 55% by weight. The total weight of the carboxylate ions in the carboxyl group and-(COO) _n ^An group is a value when the weight of the resin (A3) is 100% by weight.

Carboxyl group and contained in the resin (A3) - Measurement of the total weight of (COO) ^_n A _n group can be calculated in the same manner as the above-mentioned resin (A1).

In addition, when a neutralized product in which part or all of the carboxyl groups are neutralized with sodium ions is used as a raw material for the resin (A1) or the resin (A3) in the resin component, an inorganic layered form described later is also used. When the compound is an inorganic layered compound having sodium ions between layers, it is preferable to remove sodium ions from the neutralized product or inorganic layered compound.
As a method for removing sodium ions, one or more ions selected from the group consisting of hydrogen ions, alkaline earth metal ions and ammonium ions are used as a solution containing the neutralized product or the inorganic layered compound and a liquid medium. And ion exchange. Examples of the liquid medium used include a liquid medium that swells and cleaves an inorganic layered compound described later.

  As a method for ion exchange, the above solution is brought into contact with an ion exchange resin having one or more ions selected from the group consisting of hydrogen ions, alkaline earth metal ions, and ammonium ions, and then the residue of the ion exchange resin. , A method of passing a liquid to be treated through a column filled with an ion exchange resin containing one or more ions selected from the group consisting of hydrogen ions, alkaline earth metal ions and ammonium ions, a semipermeable membrane A method of contacting with a liquid containing one or more ions selected from the group consisting of hydrogen ions, alkaline earth metal ions and ammonium ions, and exchanging ions using pressure difference or electrodialysis, etc. Can be mentioned.

  The weight of sodium ions contained in the resin component after removing the sodium ions by the above method is 0.2% when the weight in the resin component is 100% by weight from the viewpoint that the occurrence of the PID phenomenon can be suppressed. It is preferable that it is below wt%.

(Mixture of resin (A2) and resin (A3))
When a mixture of the resin (A2) and the resin (A3) is used as the resin layer, the mixing ratio of each resin is such that the total amount of the resin (A2) and the resin (A3) is 100% by weight. (A2) is preferably 5% by weight or more and 95% by weight or less, more preferably 10% by weight or more and 90% by weight or less, and further preferably 15% by weight or more and 85% by weight or less. The resin (A3) is preferably 5% by weight or more and 95% by weight or less, more preferably 10% by weight or more and 90% by weight or less, and further preferably 15% by weight or more and 85% by weight or less. .
As the mixture, a mixture of resin pellets or a mixture of resin pellets may be used.

(Inorganic layered compound)
The resin layer may contain an inorganic layered compound. An inorganic layered compound refers to a compound in which unit crystal layers are stacked to form a layered structure. A layered structure is a structure in which atoms that are strongly bonded by a covalent bond or the like and densely arranged are stacked almost in parallel by a weak binding force such as van der Waals. Among inorganic layered compounds, clay minerals having swelling property and cleaving property to a liquid medium are preferably used.

  Clay minerals generally include (i) a type having a two-layer structure having an octahedral layer with aluminum, magnesium, etc. as a central metal above the silica tetrahedral layer, and (ii) the silica tetrahedral layer is made of aluminum. And a type having a three-layer structure in which an octahedral layer having a central metal such as magnesium is sandwiched from both sides. Examples of the two-layer structure type clay mineral (i) include kaolinite-serpentine clay minerals. The clay mineral of the three-layer structure type (ii) includes clay minerals such as talc-pyrophyllite group, smectite group, vermiculite group, mica group, brittle mica group, chlorite group, etc., depending on the number of interlayer cations. .

Specific examples of the kaolinite-serpentine group include kaolinite, dickite, nacrite, halloysite, antigolite, chrysotile, lizardite, amesite, burcherin, cronstedite, nepoite, keriaite, fraponite, blindriaite, etc. Can be mentioned.
Specific examples of the talc-pyrophyllite group include talc, willemsite, kerolite, pimelite, pyrophyllite, ferripyrophyllite and the like.
Specific examples of the smectite group include montmorillonite, beidellite, nontronite, saponite, sauconite, stevensite, hectorite, bolcon score, and swinolite.
Specific examples of the vermiculite family include 3 octahedral vermiculite, 2 octahedral vermiculite, and the like.

Specific examples of the mica group include tetrasilicic mica, sodium teniolite, muscovite, phlogopite, biotite, iron mica, eastnite, siderophyllite tetraferri iron mica, scale mica, polylithionite, celadonite. , Iron ceradonite, iron alumina ceradon stone, alumino ceradon stone, mica mica, paragonite, and lipidolite.
Specific examples of the brittle mica group include xanthophyllite, clintnite, bite mica, ananda stone, pearl mica, marguerite, and the like.
Specific examples of the chlorite group include clinochlore, chamosite, penanthite, nimite, bailicroa, donbasite, kukuite, and suedeite.

  In addition, these clay minerals treated with organic substances such as ion exchange and improved dispersibility (see Asakura Shoten, “Encyclopedia of Clay”; hereinafter may be referred to as organically modified clay minerals) are also used as inorganic layered compounds. Can be used. As said organic substance which processes a clay mineral, well-known quaternary ammonium salts, such as a dimethyl distearyl ammonium salt and a trimethyl stearyl ammonium salt, a phosphonium salt, an imidazolium salt, etc. can be used.

Among the above clay minerals, the smectite group, vermiculite group and mica group clay minerals, which are the three-layer structure type clay mineral of (ii), are preferred, and the smectite group is particularly preferred. As the smectite group, montmorillonite, beidellite, nontronite, saponite, sauconite, stevensite, and hectorite are preferable, and montmorillonite is particularly preferably used from the viewpoint of swellability to a liquid medium and cleavage.
Two or more inorganic layered compounds may be used in combination.

  The aspect ratio of the inorganic layered compound is preferably 20 or more, more preferably 100 or more, and even more preferably 200 or more. In addition, from the viewpoint of easily swelling and cleaving and improving the film formability and flexibility of the resin layer, the aspect ratio of the inorganic layered compound is preferably 10,000 or less, more preferably 5000 or less, More preferably, it is 3000 or less.

  In addition, the inorganic layered compound used preferably has an average particle size of 5 μm or less, preferably 1 μm or less, from the viewpoint of the effect of suppressing the decrease in output when the solar cell panel of the present invention is used under high voltage. It is more preferable. The aspect ratio and average particle size of the inorganic layered compound are values in the inorganic layered compound dispersion when the inorganic layered compound and the inorganic layered compound are dispersed in a liquid medium that swells and cleaves.

  In the present invention, the aspect ratio (Z) of the inorganic layered compound is defined by the formula: Z = L / a. In the formula, L is the average particle diameter of the inorganic layered compound, a is the unit thickness of the inorganic layered compound, that is, the thickness of the unit crystal layer of the inorganic layered compound, and is determined by the powder X-ray diffraction method (“instrumental analysis”). No. (a) "(1985, published by Kagaku Dojinsha, supervised by Jiro Shiokawa, p. 69).

  The average particle diameter of the inorganic layered compound is a particle diameter (volume-based median diameter) obtained by a diffraction / scattering method in a liquid medium. That is, it can be obtained by calculating a particle size distribution appropriate for the diffraction / scattering pattern from the diffraction / scattering pattern obtained when light is passed through the dispersion of the inorganic layered compound by the Mie scattering theory or the like. Specifically, for example, the measurement range of the particle size distribution is divided into appropriate sections, the representative particle diameter is determined for each section, and the particle size distribution, which is originally a continuous quantity, is converted into a discrete quantity and calculated. A method is mentioned.

In addition, the inorganic layered compound preferably has a swelling value of 5 or more, more preferably a swelling value of 20 or more according to the following swellability test. Further, those having a cleavage value of 5 or more by cleavage test described below are preferred, and those having a cleavage value of 20 or more are more preferred.
(Swellability test)
Into a 100 ml graduated cylinder, 100 ml of liquid medium is added, and 2 g of inorganic layered compound is gradually added thereto. After standing at 23 ° C. for 24 hours, the volume (ml) of the inorganic layered compound dispersion layer is read from the scale of the interface between the inorganic layered compound dispersion layer and the supernatant in the graduated cylinder. It shows that swelling property is so high that this numerical value (swelling value) is large.
[Cleavage test]
Gradually add 30 g of inorganic layered compound into 1,500 ml of liquid medium, disperser (Asada Tekko Co., Ltd., Despa MH-L, blade diameter 52 mm, rotation speed 3,100 rpm, container volume 3 L, distance between bottom surface and blades 28 mm) at a peripheral speed of 8.5 m / min and at 23 ° C. for 90 minutes, 100 ml of this dispersion is collected in a graduated cylinder. After standing for 60 minutes, the volume (ml) of the inorganic layered compound dispersion layer is read from the scale of the interface between the inorganic layered compound dispersion layer and the supernatant in the graduated cylinder. The larger this numerical value (cleavage value), the higher the cleavage property.

  In the present invention, as the liquid medium for swelling and cleaving the inorganic layered compound, when the inorganic layered compound is a hydrophilic swellable inorganic layered compound, water, alcohols (methanol, ethanol, propanol, isopropanol, ethylene glycol, diethylene glycol) Etc.), dimethylformamide, dimethyl sulfoxide, acetone and the like. Of these, water, alcohol, and a water-alcohol mixture are preferably used.

  When an organically modified inorganic layered compound is used as the inorganic layered compound, aromatic hydrocarbons such as benzene, toluene and xylene, ethers such as ethyl ether and tetrahydrofuran, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone , Aliphatic hydrocarbons such as n-pentane, n-hexane, n-octane, halogenated hydrocarbons such as chlorobenzene, carbon tetrachloride, chloroform, dichloromethane, 1,2-dichloroethane, perchloroethylene, ethyl acetate , Methyl methacrylate, dioctyl phthalate, dimethylformamide, dimethyl sulfoxide, methyl cellosolve, silicone oil and the like can be used as the liquid medium.

  The content of the inorganic stratiform compound in the resin layer is preferably 1 part by weight or more and 200 parts by weight or less, more preferably 2 parts by weight or more and 150 parts by weight or less, with respect to 100 parts by weight of the resin component. The amount is more preferably no less than 130 parts by weight and most preferably no less than 2 parts by weight and no greater than 100 parts by weight.

The resin layer may further contain a plasticizer. By including a plasticizer, flexibility can be imparted to the resin layer forming the front panel for a solar cell panel of the present invention. A plasticizer is a compound in which at least one hydroxyl group is bonded to each of two or more consecutive carbon atoms in a molecule, and the molecular weight is 200 or more and 4000 or less. Moreover, it is preferable that a plasticizer melt | dissolves in water from the point of the handleability at the time of forming a resin layer using a coating liquid.
From the viewpoint of solubility in water, the plasticizer is preferably a multimer of polyhydric alcohols such as polysorbitol, polymannitol, polydulitol, polyxylitol, polyerythritol, polyglycerin, and more preferably polyglycerin. These plasticizers may be used alone or in combination of two or more.

  From the viewpoint of the flexibility of the resin layer in the front panel for solar cell panel of the present invention, the molecular weight of the plasticizer is preferably 350 or more and 3000 or less, and more preferably 500 or more and 2500 or less.

  The resin layer may contain various additives such as an ultraviolet absorber, a colorant, an antioxidant, a light stabilizer, and an antiblocking agent in addition to the plasticizer. Two or more of these may be used in combination.

  From the viewpoint of the flexibility of the resin layer in the front panel for solar cell panel of the present invention, the content of the plasticizer is preferably 20 parts by weight or more and 150 parts by weight or less with respect to 100 parts by weight of the resin component. It is more preferably no less than 120 parts by weight, even more preferably no less than 40 parts by weight and no greater than 120 parts by weight, and most preferably no less than 60 parts by weight and no greater than 110 parts by weight.

[Method of manufacturing solar panel front plate]
The solar cell panel front plate is obtained by forming a resin layer on the glass layer. The resin layer is formed by applying a coating liquid containing a resin component and a liquid medium to the surface of the glass layer and drying the precursor film, and then heat-treating the precursor film.

The coating liquid is obtained by dissolving the resin component in a liquid medium and adjusting to a desired concentration. When the resin (A1) is used, the content of the resin component in the coating liquid is preferably 0.5% by weight to 30% by weight, and more preferably 1% by weight to 20% by weight. . Moreover, when using the mixture of resin (A2) and resin (A3), it is preferable that the total amount of these resin is 0.5 to 30 weight%, and is 1 to 20 weight%. More preferably.
When the resin component (that is, the resin (A1) or a mixture of the resin (A2) and the resin (A3)) is dissolved, a part of the carboxyl groups contained in the resin component may be neutralized at the same time. That is, a method of dissolving the resin and an alkaline earth metal ion donating compound or an ammonium ion donating compound in a liquid medium, or after dissolving the resin in a liquid medium, the hydrogen ions contained in the solution are alkalinized. A method of exchanging with earth metal ions or ammonium ions may be employed.

  Further, when the resin layer contains an inorganic layered compound or a plasticizer, the resin component, the inorganic layered compound or the plasticizer is dissolved or dispersed in the same liquid medium, the resin constituting the resin component, the inorganic layered compound or the plasticizer In addition, a method of dissolving or dispersing an alkaline earth metal ion donating compound or an ammonium ion donating compound in the same liquid medium, or after replacing the hydrogen ions contained in the resin component with alkaline earth metal ions or ammonium ions And the like, and the like.

  Examples of the liquid medium contained in the coating liquid include the same liquid medium as the liquid medium that swells and cleaves the inorganic layered compound described above. These liquid media may be used alone or in combination of two or more. When the coating liquid contains an organically modified inorganic layered compound, a liquid medium that swells and cleaves the organically modified inorganic layered compound is preferably used as the liquid medium of the coating liquid.

When producing a coating solution containing an inorganic layered compound, it is preferable to disperse the inorganic layered compound in the liquid medium by high-pressure dispersion treatment in order to sufficiently swell and cleave the inorganic layered compound in the liquid medium.
Here, the high-pressure dispersion treatment means that a mixed liquid obtained by mixing an inorganic layered compound in a liquid medium is passed through a plurality of thin tubes at a high speed, and then merged, and the mixed liquids or the mixed liquid and the inner wall of the thin tube are combined. This is a treatment method in which high shear or high pressure is applied to the mixed liquid by collision. In the high-pressure dispersion treatment, the mixed solution is passed through a thin tube having a tube diameter of about 1 μm to 1000 μm. At this time, it is preferable to process so that the maximum pressure of 100 kgf / cm ² or more is applied. Maximum pressure is more preferably at 500 kgf / cm ² or more, and particularly preferably 1000 kgf / cm ² or more. Further, when the mixed solution passes through the narrow tube, the maximum arrival speed of the dispersion is preferably 100 m / s or more, and the heat transfer rate due to pressure loss is preferably 100 kcal / hour or more.

  For the high-pressure dispersion treatment, a high-pressure dispersion device such as an ultrahigh-pressure homogenizer (trade name: Microfluidizer) manufactured by Microfluidics Corporation, a nanomizer manufactured by Nanomizer, a Manton Gorin type high-pressure dispersion device, or a homogenizer manufactured by Izumi Food Machinery can be used. . The liquid mixture subjected to the high-pressure dispersion treatment may contain a resin component and the plasticizer.

  More preferably, the coating solution contains a surfactant. By applying a coating liquid containing a surfactant to the glass layer to form a resin layer, the adhesion between the resin layer and the glass layer can be improved. The content of the surfactant is 0.001 part by weight or more and 5 parts by weight or less when the liquid medium contained in the coating liquid is 100 parts by weight.

  As the surfactant, a known surfactant such as an anionic surfactant, a cationic surfactant, a zwitterionic surfactant, a nonionic surfactant or the like can be used. In particular, an alkali metal salt of a carboxylic acid having an alkyl chain having 6 to 24 carbon atoms, an ether type nonionic surfactant such as a polydimethylsiloxane-polyoxyethylene copolymer (silicone nonionic surfactant) ) Or a fluorine-type nonionic surfactant (fluorine-based nonionic surfactant) such as a perfluoroalkylethylene oxide compound is preferable from the viewpoint of improving adhesion.

  As a method of applying the coating liquid to the glass layer, a gravure method such as a direct gravure method or a reverse gravure method, a roll coating method such as a two roll beat coating method, a bottom feed three reverse coating method, a doctor knife method, A die coating method, a bar coating method, a dipping method, a spray coating method, or the like can be applied. It is preferable to employ a dipping method, a spray coating method, or a gravure method because a layer can be easily provided.

The precursor film made of the coating solution applied to the glass layer by the above method is heat-treated. Examples of the heat treatment method include dry heat treatment and wet heat treatment. These can be carried out singly or in combination, and are preferably carried out in combination. Note that when heat treatment is performed in combination, wet heat treatment is preferably performed after dry heat treatment.
Here, the dry heat treatment refers to a treatment that is held in an atmosphere of 100 ° C. or more and 300 ° C. or less and a water vapor concentration of less than 50 g / m ³ . The dry heat treatment temperature is preferably 120 ° C. or higher and 200 ° C. or lower. The time for the dry heat treatment is 1 second or more and 1 hour or less. The water vapor concentration during the dry heat treatment is preferably 0 g / m ³ or more and 40 g / m ³ or less. Examples of the dry heat treatment method include a method of contacting with a heat roll, a method of contacting with a heat medium such as air, a method of heating with infrared rays, and a method of heating with microwaves. You may use the heating in the case of the below-mentioned assembly of the solar cell panel as a dry heat processing.

Further, the wet heat treatment is a treatment for holding in an atmosphere having a water vapor concentration of more than 290 g / m ³ at a temperature of 100 ° C. or higher or in water of 80 ° C. or higher. The time for the wet heat treatment is 1 second or more and 1 hour or less. If the water vapor concentration at 100 ° C. above the temperature of the treatment in an atmosphere of 290 g / ^{m 3} greater, the temperature is preferably in the range of 120 ° C. or higher 200 ° C. or less, the water vapor concentration is 500 g / ^{m 3} or more 20000 g / ^{m 3} or less Within the range of is preferable. In the case of treatment in water at 80 ° C. or higher, the temperature is preferably in the range of 100 ° C. to 140 ° C. Before the wet heat treatment, the precursor film may be aged under conditions of, for example, 23 ° C. and a humidity of 50% RH. In order to remove moisture contained in the precursor film, a drying treatment may be performed after the wet heat treatment. The drying treatment is preferably performed at a humidity of 50% RH or less and a temperature of 20 ° C. to 100 ° C. for 1 second to 24 hours.

  By heat-treating the precursor film, the reaction between the hydroxyl group and the carboxyl group further proceeds, and when the solar cell panel is used under a high voltage, the effect of suppressing the output decrease is increased. Moreover, since the resin layer which is excellent in a flexibility can be formed when a resin layer contains a plasticizer, the crack of a resin layer can be suppressed at the time of the assembly of the following solar cell panel.

The glass layer and the resin layer are preferably subjected to surface treatment from the viewpoint of improving the adhesion of a sealing material layer described later. Examples of the surface treatment method include corona treatment, ozone treatment, plasma treatment, electron beam radiation treatment, ultraviolet irradiation treatment, acid treatment, and anchor coat treatment. These methods may be used alone or in combination of two or more.
As the anchor coat treatment, an anchor coat layer can be formed using an ethyleneimine-based, two-component curable urethane-based, acid-modified olefin-based coating agent, or the like. The thickness of the anchor coat layer is preferably in the range of 0.01 μm to 20 μm.

[Solar panel]
FIG. 1 is a view showing a solar cell panel using a solar cell panel front plate (hereinafter referred to as a front plate) according to the present invention. The front plate 1 is provided on the light receiving surface side of the solar battery cell 3, and a back sheet 5 is provided on the surface opposite to the light receiving surface. Between the front plate 1 and the solar battery cell 3, and between the back sheet 5 and the solar battery cell 3, there are a sealing layer 2 made of the first sealing material and a sealing layer 4 made of the second sealing material. It is provided and the solar battery cell 3 is sealed. In addition, in the front plate 1, the surface facing the light receiving surface of the solar battery cell 3 is the resin layer 1 ″, and the outermost surface is the glass layer 1 ′.

  The sealing layers 2 and 4 provided between the solar battery cell 3 and the front plate 1 and the back sheet 5 are made of a first sealing material and a second sealing material, respectively. As a raw material of the sealing material, an ethylene-unsaturated ester copolymer, an elastomer made of an ethylene-α-olefin copolymer, an ionomer obtained by ion-crosslinking an ethylene-unsaturated carboxylic acid copolymer, polyvinyl butyral, a silicone resin, Examples thereof include an epoxy resin, a fluorinated polyimide resin, an acrylic resin, and a polyester resin. The sealing material is preferably in the form of a sheet or film. The first sealing material and the second sealing material may be the same raw material sheet or film, but may be different raw materials.

From the viewpoint of handling at the time of manufacturing the solar battery panel and protection of the solar battery cell 3, it is preferable to use an ethylene-unsaturated ester copolymer. Examples of the ethylene-unsaturated ester copolymer include an ethylene-carboxylic acid vinyl ester copolymer and an ethylene-α, β unsaturated carboxylic ester copolymer.
Examples of the ethylene-carboxylic acid vinyl ester copolymer include an ethylene-vinyl acetate copolymer. Examples of the ethylene-α, β unsaturated carboxylic acid ester copolymer include ethylene-methyl methacrylate and ethylene-methyl acrylate.
The sealing material may contain a crosslinking agent, a crosslinking assistant, a silane coupling agent, and the like.

The thickness of the sealing layers 2 and 4 is preferably in the range of 0.1 mm to 1 mm. The sealing layers 2 and 4 may be provided only on one side of the solar battery cell 3, or may be provided on both sides.
In the figure, the sealing material layers 2 and 4 are provided on the front side and the back side of the solar cell 3, but the resin layer 1 "of the front plate 1 and the solar cell 3 are in contact with each other. Need only be provided with the sealing layer 4 on the back side of the solar battery cell 3. Also, in the solar battery panel of the present invention, when the back sheet is provided with a sealing material layer in advance, both the front and back surfaces are sealed. No material layer is required

The back sheet 5 has a layer made of resin. As the resin used for the backsheet 5, a thermoplastic resin, a thermosetting resin, a photocurable resin, or the like can be used.
Thermoplastic resins include olefin resin, ester resin, amide resin, acrylic resin, styrene resin, hydrophobic cellulose resin, chlorine resin, fluorine resin, hydrogen bonding resin, carbonate resin, sulfone resin, ether sulfone resin, ether ketone Examples thereof include resins, phenylene oxide resins, methylene oxide resins, and imide resins.

Examples of the thermosetting resin include phenol resin, melamine resin, urea resin, and ethyleneimine resin. Moreover, as a thermosetting resin, you may use resin which a thermoreactive compound containing an epoxy compound, a (meth) acryloyl compound, an allyl compound, a vinyl compound, etc. reacts in thermal polymerization initiator presence.
Examples of the photocurable resin include an epoxy resin and an acrylic resin obtained by polymerizing an epoxy compound or an acrylic compound using a photopolymerization initiator.

  The backsheet 5 may be a single layer or a multilayer, and may have a metal layer such as a metal deposit such as alumina, aluminum, or silica, or a metal foil. The back sheet 5 may be any of a non-stretched sheet, a uniaxially stretched sheet, and a biaxially stretched sheet.

[Method for manufacturing solar cell panel]
In an example of a method for manufacturing a solar cell panel using the front panel for a solar cell panel according to the present invention, first, both sides of a solar cell are sandwiched between two or more sheet-like sealing materials. Next, the solar cell panel front plate of the present invention is brought into contact with one side thereof, and the back sheet is brought into contact with the other side to produce a solar cell panel preliminary body. In that case, the resin layer in the front panel for solar cell panels is arrange | positioned in the surface facing a photovoltaic cell.
Next, the solar cell panel preliminary body is placed in the chamber, and the inside of the chamber is decompressed to be in a vacuum state. After making the inside of a chamber into a vacuum state, a solar cell panel preliminary body is heated in the chamber to the temperature which a sealing material fuse | melts mutually. After the sealing materials are melted to some extent, the vacuum state is maintained by stopping the decompression in the heated state, and pressure is applied to the front panel and the back sheet for the solar panel of the solar panel preliminary body. Press the panel spare. The solar cell panel preliminary body is heated in a vacuum state and a pressurized state, whereby the resin in the sealing material is fused.

Another example of a method for manufacturing a solar battery panel is that a solar battery cell is placed on one surface of a sheet-shaped sealing material, and a front panel or a back sheet for the solar battery panel is further provided on the solar battery cell. Place. When a solar panel front plate is placed on a solar cell, a back sheet is placed on the surface opposite to the surface on which the solar cell of the sealing material is placed, and a solar cell panel preliminary body is manufactured. . In addition, when a back sheet is placed on the solar cell, a solar panel front plate is placed on the surface opposite to the surface on which the solar cell of the sealing material is placed to produce a solar cell spare. To do. At this time, the resin layer in the front panel for solar cell panel is disposed on the surface facing the solar cell.
Next, the solar cell panel preliminary body is placed in the chamber, and the inside of the chamber is decompressed to be in a vacuum state. After the chamber is evacuated, the solar cell panel preliminary body is heated in the chamber to a temperature at which the resin constituting the sealing material melts. After melting the sealing material to some extent, while maintaining the heated state, the decompression is stopped and the vacuum state is maintained, and pressure is applied to the front panel and the back sheet for the solar panel of the solar panel preliminary body. Press the spare body. When the solar cell panel preliminary body is heated in a vacuum state and a pressurized state, the sheet made of the sealing resin is crosslinked.

Hereinafter, the present invention will be described based on examples. First, a method for measuring physical property values in the following examples will be described.
[Thickness measurement]
The thickness of the glass layer was measured using a digital thickness meter (contact type thickness meter, trade name: Ultra High Precision Deci-Microhead MH-15M, manufactured by Nippon Optics Co., Ltd.). The thickness of the resin layer was determined from cross-sectional observation with a transmission electron microscope (TEM).

(Particle size measurement)
The average particle size of the inorganic layered compound in the coating liquid containing the inorganic layered compound was measured by the following procedure using a laser diffraction / scattering type particle size distribution measuring device (LA910, manufactured by Horiba, Ltd.). The measured value of the coating liquid was regarded as the average particle diameter L of the clay mineral in the resin composition layer.
Procedure 1: The average particle diameter of the clay mineral in the coating liquid described later was measured with a paste cell at an optical path length of 50 μm.
Procedure 2: The average particle size of the clay mineral in the solution obtained by diluting the above coating solution to about 200 times is measured by the flow cell method at an optical path length of 4 mm. It was confirmed that the clay mineral was sufficiently swollen and cleaved in the liquid.

[Aspect ratio calculation]
Using an X-ray diffractometer (XD-5A, manufactured by Shimadzu Corporation), diffraction measurement of the inorganic layered compound is performed by a powder method, and the average thickness of each inorganic layered compound (hereinafter, unit thickness) is measured. A). Using the average particle diameter L obtained by the above method, the aspect ratio Z of the inorganic layered compound was calculated by the formula Z = L / a. In addition, X-ray diffraction measurement was also performed on the dried coating liquid, and the surface spacing of the inorganic layered compound in the dried coating liquid was larger than that of the raw inorganic layered compound. It was confirmed that the compound was dispersed.

[Calculation method for amount of hydroxyl group contained in resin component and amount of carboxylate ion in carboxyl group]
In this example, a mixture of resins (A2) and (A3) was used as the resin component. Further, as the resin (A3), a resin obtained by neutralizing a part of the carboxyl group of the resin containing a carboxyl group with at least one cation selected from the group consisting of alkaline earth metal ions and ammonium ions was used.
In the coating solution, polyvinyl alcohol (completely saponified product) was used as the hydroxyl group-containing resin (A2), and polyacrylic acid was used as a raw material for the carboxyl group-containing resin (A3). From the following formula, the amount of the hydroxyl group in polyvinyl alcohol (mole) and the amount of the carboxyl group in polyacrylic acid (mole) are calculated, and the respective values are divided by the sum of the two, respectively in mol% units. (However, the total amount of the hydroxyl group and carboxyl group is 100 mol%).
Substance amount of hydroxyl group (mol) = (Weight (g) of resin (A2)) / (Molecular weight per monomer unit constituting resin (A2))
Substance amount of carboxylate ion (mol) = (weight of resin (A3) (g)) / (molecular weight per unit of monomer unit constituting resin (A3))
The values of the hydroxyl group substance amount and the carboxylate ion substance amount in the coating liquid, the hydroxyl group substance amount and the carboxylate ion substance amount value in the resin composition layer formed using the coating liquid, did.

[Calculation method of total weight of carboxylate ion in hydroxyl group and carboxyl group contained in resin component]
From the following formula, the weight of the hydroxyl group and the weight of the carboxyl group (however, the weight of the resin component is 100% by weight) were calculated and totaled.
Weight of hydroxyl group (% by weight) = (17 / (molecular weight per unit of monomer unit constituting resin (A2))) × (weight of resin (A2) (g) / weight of resin component (A) (g) ) × 100
Weight of carboxylate ion (% by weight) = (45 / (molecular weight per unit of monomer unit constituting resin (A3))) × (weight of resin (A3) (g) / weight of entire resin component (g) ) × 100
In the coating liquid, the weight of the entire resin component is the sum of the weight of the resin (A2) and the weight of the resin (A3).
The total weight value of hydroxyl groups and carboxylate ions contained in the resin component in the coating solution is the total weight value of hydroxyl groups and carboxylate ions contained in the resin component in the resin layer formed using the coating solution. It was.

[Sodium ion concentration measurement]
Using an inductively coupled plasma optical emission spectrometer (Optima 3000, manufactured by PerkinElmer), the sodium ion concentration of the precursor film (dried product of the coating solution before heat treatment) was measured, and the sodium ion concentration in the resin composition, respectively. Asked. The sample preparation method is as follows. 1 g of a dried product of the coating solution was sampled, 1 ml of 96% sulfuric acid was added, and then incinerated with an electric furnace, and the remaining residue was dissolved in 5% hydrochloric acid. The solution was used in an inductively coupled plasma emission spectrometer, and the sodium ion concentration was measured for each.

[Measurement of at least one cation concentration selected from the group consisting of alkaline earth metal ions and ammonium ions]
The cation concentration in the resin component such as alkaline earth metal ions and ammonium ions was calculated from the added amount of alkaline earth metal ion donor compound and ammonium ion donor added to the coating solution (however, the coating solution) The total of the weight of polyvinyl alcohol and the weight of polyacrylic acid is 100 parts by weight).

[PID test]
(Manufacture of solar panel for PID test)
A solar cell panel (200 mm × 200 mm) was produced by laminating under the following conditions using a solar cell panel front plate described below and the following materials.
<Material>
Solar cell: polycrystalline silicon cell (model number TSM62TNA, manufactured by T-SEC)
Sealing material: Using a ethylene-vinyl acetate copolymer manufactured by Sumitomo Chemical Co., Ltd., a press sheet having a thickness of 0.5 mm was prepared at 100 ° C., and this was used as the sealing material.
Back sheet: Polyester-based sheet (model number SPE-35, manufactured by SFC)
End face sealing tape: Acrylic foam tape (model number Y-4608 (manufactured by Sumitomo 3M))
Ribbon wire: manufactured by Hitachi Cable, Ltd. Lead wire: Model No. VSF1.25 (manufactured by Yazaki Corp.)
Junction box: Material Zylon 644Z (Keihin Chemitox Co., Ltd.)
Sealing material: Silicone adhesive (Model No. PV-804, manufactured by Toray Dow Corning Co., Ltd.)
Thread solder: SPARKLE ESC21 (Senju Metal Industry Co., Ltd.)
Aluminum frame: made by Jiangyin Hitech Industry

<Lamination conditions>
Laminator: Kitagawa Seiki Co., Ltd. Hot plate temperature: 140 ° C
Vacuuming time: 5 min
Pressure arrival time: 30 sec
Press time: 25 min

(PID test)
In the PID test, a voltage of 1000 V was applied at a temperature of 60 ° C. and a humidity of 85% RH with water applied to the light receiving surface side of the solar cell panel, and the maximum output value after 96 hours was measured relative to the initial maximum output value. The maximum output retention rate Pm was evaluated by the following formula.
Pm (%) = 100 × (Pb) / (Pa)
Pa: Maximum output value after holding for 0 hour (initial) (W)
Pb: Maximum output value after holding for 96 hours (W)

[Adhesion evaluation]
A solar cell panel front plate and a sealing material, which will be described later, were bonded together under the above-mentioned laminating conditions to obtain a sample for adhesion evaluation. Tensilon Universal Material Testing Machine (Orientec Co., Ltd.) has the force required to peel off the sealing material layer from the front plate under the conditions of a peel width of 10 mm, a peel angle of 180 °, and a peel speed of 100 mm / min in an atmosphere at 23 ° C. ) And measured as peel strength (N / 10 mm).

[Preparation of coating solution]
(1) Preparation of first coating liquid In a dispersion kettle (trade name: Despa MH-L, manufactured by Asada Tekko Co., Ltd.), 1300 g of ion-exchanged water (specific electric conductivity 0.7 μs / cm or less) and polyvinyl 130 g of alcohol (AQ2117; manufactured by Kuraray Co., Ltd., degree of saponification; 99.6%, degree of polymerization 1,700) was mixed, and the temperature was raised to 95 ° C. under low speed stirring (1500 rpm, peripheral speed 4.1 m / min). Warm up. This was stirred at the same temperature for 30 minutes to dissolve the polyvinyl alcohol, and then cooled to 60 ° C. to obtain an aqueous polyvinyl alcohol solution.
While stirring this polyvinyl alcohol aqueous solution (60 ° C.), an aqueous alcohol solution obtained by mixing 122 g of 1-butanol, 122 g of isopropyl alcohol and 520 g of ion-exchanged water was dropped over 5 minutes. After the completion of dropping, the mixture was switched to high speed stirring (3000 rpm, peripheral speed = 8.2 m / min), and 82 g of high purity montmorillonite (trade name: Kunipia G; manufactured by Kunimine Industries Co., Ltd.) was gradually added. And stirring was continued for 60 minutes.
Thereafter, 243 g of isopropanol was further added over 15 minutes, and the mixture was cooled to room temperature to obtain a clay mineral-containing liquid. 0.06 part by weight of nonionic surfactant (polydimethylsiloxane-polyoxyethylene copolymer, trade name: SH3746, manufactured by Toray Dow Corning Co., Ltd.) with respect to this clay mineral-containing liquid Was added under stirring at a low speed (1500 rpm, peripheral speed 4.1 m / min) to prepare a clay mineral dispersion.

Further, in another dispersion kettle, 1067 g of ion-exchanged water (specific electrical conductivity 0.7 μs / cm or less) and 33 g of polyacrylic acid (manufactured by Wako Pure Chemical Industries, Ltd., average molecular weight 1,000,000) were added. After mixing, a resin solution was produced at room temperature under low speed stirring (1500 rpm, peripheral speed 4.1 m / min).
2519 g of the above clay mineral dispersion and 1100 g of the resin solution are gradually mixed under low speed stirring (1500 rpm, peripheral speed 4.1 m / min) to obtain a mixed liquid, and this mixed liquid is further mixed with a high pressure dispersing apparatus (trade name: The first dispersion was obtained by processing under a pressure condition of 1100 kgf / cm ² using an ultrahigh pressure homogenizer M110-E / H (manufactured by Microfluidics Corporation).

About the said 1st dispersion liquid, after passing through the column filled with H ion type ion exchange resin so that pH might be set to 3, ammonia water is added, pH is set to 6, and-(COO) _n A ⁿ group There was obtained a first coating liquid is a -COONH _4.
The average particle size (L) of the cleaved montmorillonite in the first coating liquid was 560 nm, the unit thickness (a) obtained from powder X-ray diffraction was 1.2156 nm, and the aspect ratio (Z) was 460. It was.

(2) Second coating solution In the first coating solution, except that the pH is set to 6 using calcium hydroxide instead of ammonia water,-( _COO) n ^{a n} groups - was obtained _(COO) coating solution is 2 Ca (hereinafter referred to as a second coating liquid). The cleaved montmorillonite average particle size (L) in this second coating solution was 560 nm, the unit thickness (a) obtained from powder X-ray diffraction was 1.2156 nm, and the aspect ratio (Z) was 460. It was.

(3) Preparation of 3rd coating liquid First, polyvinyl alcohol aqueous solution was obtained in the procedure similar to a 1st coating liquid.
While stirring this polyvinyl alcohol aqueous solution (60 ° C.), an aqueous alcohol solution obtained by mixing 122 g of 1-butanol, 122 g of isopropyl alcohol and 520 g of ion-exchanged water was dropped over 5 minutes.
Thereafter, 243 g of isopropanol was further added over 15 minutes and the mixture was cooled to room temperature to obtain a polyvinyl alcohol solution. 0.06 part by weight of a nonionic surfactant (polydimethylsiloxane-polyoxyethylene copolymer, trade name: SH3746, manufactured by Toray Dow Corning Co., Ltd.) (in the coating solution described later) Was added under stirring at a low speed (1500 rpm, peripheral speed 4.1 m / min) to prepare a resin solution (1).

Further, in another dispersion kettle, 1067 g of ion-exchanged water (specific electrical conductivity 0.7 μs / cm or less) and 33 g of polyacrylic acid (manufactured by Wako Pure Chemical Industries, Ltd., average molecular weight 1,000,000) were added. After mixing, a resin solution (2) was produced at room temperature under low speed stirring (1500 rpm, peripheral speed 4.1 m / min).
2438 g of the above resin solution (1) and 1100 g of the resin solution (2) are gradually mixed under low speed stirring (1500 rpm, peripheral speed 4.1 m / min) to form a mixed solution, and this mixed solution is further mixed with a high pressure dispersion device. A resin mixed solution was obtained by processing under a pressure condition of 1100 kgf / cm ² using (trade name: Super High Pressure Homogenizer M110-E / H, manufactured by Microfluidics Corporation).

For the resin mixture, aqueous ammonia was added, the pH was adjusted to ^{_{6, - (COO) n A}} n group to obtain a third coating liquid is -COONH _4.

(4) Fourth coating solution In the first coating solution, except that the pH is set to 6 using sodium hydroxide instead of ammonia water,-(COO ) A coating solution (hereinafter referred to as a fourth coating solution) in which the _n ^An group is — (COO) ₂ Na was obtained. The cleaved montmorillonite average particle diameter (L) in this fourth coating solution was 560 nm, the unit thickness (a) obtained from powder X-ray diffraction was 1.2156 nm, and the aspect ratio (Z) was 460. It was.

[Example 1]
After bonding the masking tape to the anti-glare surface of the glass layer (white plate mold heat-treated glass (manufactured by AGC Fabricec Co., Ltd.)), the first coating liquid is applied by dipping method to a temperature of 80 ° C. And dried for 20 minutes to form a resin layer on the glass. Then, the masking tape was removed, and the front panel for solar cell panels was obtained.
The resin layer has a thickness of about 0.5 μm, the sodium concentration in the resin layer is 0.7 parts by weight, and the carboxylate ion concentration is 43.4 parts by weight (however, all of the polyvinyl alcohol contained in the resin layer). The total of the weight and the weight of polyacrylic acid is 100 parts by weight). The amount of the hydroxyl group contained in the resin component forming the resin layer was 86 mol%, and the amount of the carboxylate ion contained in the carboxyl group and _4- COONH ₄ group was 14 mol% (however, all The total substance amount of the groups is 100 mol%).
Further, the amount of carboxylate ions in the carboxyl group when the total amount of substances of the carboxyl group and —COONH ₄ group is 100 mol% is 60 mol%, and the carboxylate ion in the —COONH ₄ group is The amount of substance was 40 mol%.

The total weight of the hydroxyl group, carboxyl group and -COONH ₄ group contained in the resin component (A) was 43.4% by weight.
Since the specific gravity of the resin components (polyvinyl alcohol and polyacrylic acid) is 1.2, the total charged amount is 163 g, the specific gravity of high purity montmorillonite, which is an inorganic layered compound, is 2.4, and the charged amount is 82 g. When the volume of the layer 1 was 100 volume%, the volume fraction of the inorganic layered compound was 20 volume%, and the volume of the resin component was 80 volume%. Using the obtained front panel for a solar cell panel, a sample for assembly and adhesion evaluation of the solar cell panel was produced and evaluated under the above conditions. The results are shown in Table 1.

[Example 2]
A solar cell panel front plate was obtained in the same manner as in Example 1 except that the second coating solution was used instead of the first coating solution.
The thickness of the resin layer is about 0.5 μm, the sodium concentration in the resin layer is 0.7 parts by weight, and the carboxylate ions are 43.4 parts by weight (however, the weight of the polyvinyl alcohol contained in the resin layer is The total weight of acrylic acid is 100 parts by weight). The amount of substance of hydroxyl groups contained in the resin component for forming the resin layer is 86 mol%, a carboxyl group and - the amount of substance of (COO) carboxylate ions contained in 2 _Ca groups was 14 mol% (However, the total amount of all groups is 100 mol%).
In addition, the amount of carboxylate ions in the carboxyl group when the total amount of carboxyl group and — (COO) ₂ Ca group is 100 mol% is 60 mol%, and — (COO) ₂ Ca group The amount of the carboxylate ion contained therein was 40 mol%.

The total weight of the hydroxyl group, carboxyl group and — (COO) ₂ Ca group contained in the resin component (A) was 43.4% by weight.
In addition, since the specific gravity of the resin component is 1.2 and the specific gravity of the high purity montmorillonite which is an inorganic layered compound is 2.4, when the volume of the resin layer 2 is 100% by volume, the volume fraction of the inorganic layered compound is The volume of 20 volume% and the resin component was 80 volume%. Using the obtained front panel for a solar cell panel, a sample for assembly and adhesion evaluation of the solar cell panel was produced and evaluated under the above conditions. The results are shown in Table 1.

Example 3
A front panel for a solar cell panel was obtained in the same manner as in Example 1 except that the third coating solution was used instead of the first coating solution.
The thickness of the resin layer is about 0.5 μm, the sodium concentration in the resin layer is 0.1 parts by weight or less (lower than the lower limit of detection), and the carboxylate ion is 43.4 parts by weight (all included in the resin layer) The total weight of polyvinyl alcohol and polyacrylic acid is 100 parts by weight). Further, the amount of the hydroxyl group contained in the resin component forming the resin layer was 86 mol%, and the amount of the carboxylate ion contained in the carboxyl group and the —COONH ₄ group was 14 mol% (provided that The total amount of all groups is 100 mol%).
In addition, the amount of carboxylate ions in the carboxyl group when the total amount of the carboxyl group and —COONH ₄ group is 100 mol% is 60 mol%, and the carboxylate contained in the —COONH ₄ group The amount of ions was 40 mol%.

The total weight of the hydroxyl group, carboxyl group and -COONH ₄ group contained in the resin component (A) was 43.4% by weight.
Further, when the volume of the resin layer was 100% by volume, the volume of the resin component was 100% by volume. Using the obtained front panel for a solar cell panel, a sample for assembly and adhesion evaluation of the solar cell panel was produced and evaluated under the above conditions. The results are shown in Table 1.

[Comparative Example 1]
A front panel for a solar cell panel was obtained in the same manner as in Example 1 except that the fourth coating solution was used instead of the first coating solution.
The thickness of the resin layer is about 0.5 μm, and the sodium concentration in the resin composition layer is 3 parts by weight (provided that the total weight of polyvinyl alcohol and polyacrylic acid contained in the resin layer is 100 parts by weight) )Met. The amount of hydroxyl group contained in the resin component forming the resin layer was 86 mol%, and the amount of carboxylate ion contained in the carboxyl group and -COONa group was 14 mol% (provided that The total amount of all groups is 100 mol%).
In addition, the amount of carboxylate ions in the carboxyl group when the total amount of the carboxyl group and —COONa group is 100 mol% is 60 mol%, and the carboxylate ions contained in the —COONa group The amount of substance was 40 mol%.

The total weight of the hydroxyl group, carboxyl group and -COONa group contained in the resin component (A) was 43.4% by weight.
Since the specific gravity of the resin component is 1.2 and the specific gravity of the high purity montmorillonite is 2.4, when the volume of the resin layer is 100% by volume, the volume fraction of the inorganic layered compound is 20% by volume, the resin component The volume of was 80% by volume. Using the obtained front panel for a solar cell panel, a sample for assembly and adhesion evaluation of the solar cell panel was produced and evaluated under the above conditions. The results are shown in Table 1.

[Comparative Example 2]
A front panel for a solar cell panel was obtained in the same manner as in Example 1 except that the resin layer was not provided. Using this solar cell panel front plate, solar cell panel assembly and adhesion evaluation samples were prepared and evaluated under the above conditions. The results are shown in Table 1.

DESCRIPTION OF SYMBOLS 1 Front plate 2, 4 Sealing layer 3 Solar cell 5 Back sheet

Claims (5)

A solar cell panel front plate having a glass layer and a resin layer in contact with the glass layer, wherein the resin layer is a layer containing the following resin (A1), or the following resin (A2) and the following resin ( A front panel for a solar cell panel which is a layer containing a mixture with A3).
Resin (A1): hydroxyl group, carboxyl group,-(COO) _n A ⁿ group (wherein A is at least one cation selected from the group consisting of alkaline earth metal ions and ammonium ions, and n is Resin (A2): Resin containing hydroxyl group Resin (A3): Carboxyl group and — (COO) _n ^An group (wherein A is an alkaline earth metal ion, A resin containing at least one cation selected from the group consisting of ammonium ions, and n is the valence of A)   The solar cell panel front plate according to claim 1, wherein the resin layer further contains an inorganic layered compound.   The thickness of the said resin layer is 0.01 micrometer or more and 100 micrometers or less, The front plate for solar cell panels of Claim 1 or 2. Applying a coating liquid containing the following resin (A1) or a coating liquid containing a mixture of the following resin (A2) and the following resin (A3) to at least one surface of the glass substrate;
And a step of drying the coating liquid applied to the glass substrate.
Resin (A1): hydroxyl group, carboxyl group,-(COO) _n A ⁿ group (wherein A is at least one cation selected from the group consisting of alkaline earth metal ions and ammonium ions, and n is Resin (A2): Resin containing hydroxyl group Resin (A3): Carboxyl group and — (COO) _n ^An group (wherein A is an alkaline earth metal ion, A resin containing at least one cation selected from the group consisting of ammonium ions, and n is the valence of A)   A solar battery in which the front panel for a solar battery panel according to any one of claims 1 to 3, a first sealing material, a solar battery cell, a second sealing material, and a back sheet are laminated in this order. panel.

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