JP2014015566A - Coating agent composition and backside protective sheet for solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating agent composition having excellent water vapor barrier properties and high adhesion to a substrate, and to provide a backside protective sheet for a solar cell.SOLUTION: The coating agent composition of the present invention is obtained by mixing: an acrylic copolymer (A) containing, as monomers, a radically polymerizable unsaturated carboxylic acid ester (A-1) having a hydroxyl group or an epoxy ring and a radically polymerizable unsaturated carboxylic acid ester (A-2) having no reactive functional group; an isocyanate compound (B) having two or more isocyanate groups in one molecule; and an epoxy compound (C) having at least one or more repeating units represented by general formula (1).

Description

  The present invention relates to a coating agent composition and a back surface protective sheet for solar cells.

  The solar cell module includes a solar cell element, a back surface protection sheet (back surface protection base material) that supports the solar cell element, and a transparent base material (transparent glass plate, transparent resin sheet, etc.) provided on the light receiving side of the solar cell element. As basic elements. In the solar cell module, in order to protect the solar cell element from the external environment, the solar cell element is sealed between the back surface protection sheet and the light receiving side transparent base material. This sealing structure is laminated with a sealant sheet made of EVA (ethylene vinyl acetate resin) interposed between the light-receiving side transparent base material and the solar cell element and between the back surface protection base material and the solar cell element, respectively. This is realized by forming a body and vacuum-pressure forming while heating the laminated body.

  Conventionally, several structures are proposed as a back surface protection sheet which comprises a solar cell module. In these back surface protection sheets, a coating composition containing a resin component is applied to the back surface protection sheet, or films having different characteristics are laminated with adhesives to form multiple layers, gas barrier properties such as water vapor and oxygen gas, and weather resistance Has been given sex.

  For example, in Patent Document 1, in a polyester film having a coating film of a hydroxyl group-introduced acrylic resin to which an ultraviolet absorber and / or a hindered amine compound is added on one side or both sides, an isocyanate compound is added to the hydroxyl group-introduced acrylic resin. Describes a technique capable of improving the adhesion of the coating film to the polyester film and suppressing the color change.

  Patent Document 2 has a polymer base material containing first white inorganic particles, and a reflective layer containing a binder and second white inorganic particles formed on at least one side of the polymer base material. In a solar cell backsheet, a technique is described in which an acrylic resin is used as a binder for the reflective layer, or an epoxy-based or isocyanate-based crosslinking agent is used for the reflective layer.

  Further, Patent Document 3 discloses a curable coating composition containing a hydroxyl group-containing (meth) acrylic resin, an organic polyisocyanate compound, an epoxy resin, an antioxidant and / or a light stabilizer in a predetermined ratio. Things are disclosed.

  On the other hand, for the purpose of expressing the back protection sheet with design by coloring, a relatively inexpensive resin is used for the film used for the outermost layer constituting the back protection sheet, and the adhesive used for the bonding is black. A technique for developing a black color by incorporating a pigment has also been proposed.

  For example, Patent Document 4 discloses a solar cell back surface protective sheet in which a black adhesive layer containing a perelin black pigment is supported on a white film or the like that reflects infrared light of 700 to 1200 nm by 60 to 100%. Yes.

  Patent Document 5 discloses a sun having a white layer containing a white pigment having a particle size of 0.5 μm or more and 1.5 μm or less and a black layer containing a black pigment that transmits near infrared rays having a wavelength of 750 nm to 1500 nm. As a method for forming a black layer of a back surface protection sheet for a battery, forming an adhesive layer containing a black material on a base film is disclosed.

JP 2005-015557 A JP 2011-165967 A JP 2012-82365 A JP 2011-155175 A JP2012-19138A

  However, in the coating film formed on the polyester film described in Patent Document 1, adhesion to the polyester film is improved by adding an isocyanate compound and an ultraviolet absorber and / or a light absorber to the hydroxyl group-introduced acrylic resin. However, although it is said that deterioration such as fading color caused by ultraviolet rays or visible light can be suppressed, no examination has been made on the water vapor barrier property of the coating film, and it is used as a back surface protection sheet for solar cell modules. In this case, it is necessary to laminate another film having a water vapor barrier property.

  In addition, in the reflective layer formed on the back sheet described in Patent Document 2, it is estimated that the strength and adhesiveness can be improved by adding an epoxy-based, isocyanate-based or the like crosslinking agent, but it was actually used. No examples are given. Further, the reflective layer is intended to improve light reflectivity while reducing the weight, and for a barrier such as water vapor, a barrier layer such as a deposited layer of inorganic silica or a sheet of metal aluminum or the like is used. It is necessary to provide it.

  Furthermore, although the curable coating agent composition described in Patent Document 3 is superior in weather resistance to conventional products, it is not sufficient.

  On the other hand, in Patent Documents 4 and 5, an adhesive containing a black pigment is used. However, since the chroma of the pigment is low, the design is not excellent and the thickness of the adhesive is increased in order to satisfy a desired appearance. Therefore, in addition to the increase in cost, the coatability also deteriorates. In addition, since a non-aqueous solvent is used as the adhesive composition, there is a possibility of affecting the environment.

  The present invention has been made in view of the above, and has a coating composition that has excellent water vapor barrier properties and high adhesion to a substrate film, and also has excellent long-term moist heat aging and design properties, and the sun. It aims at providing the back surface protection sheet for batteries.

で表される繰り返し単位を１以上有するエポキシ化合物（Ｃ）と、を混合することを特徴とする。 In order to solve the above-mentioned problems, the coating agent composition of the present invention is selected from the group consisting of radical polymerization radical polymerizable unsaturated carboxylic acid and radical polymerization radical polymerizable unsaturated carboxylic acid ester having a hydroxyl group or an epoxy ring. One or more compounds (A-1) and one or more compounds (A-2) selected from the group consisting of radically polymerizable radically polymerizable unsaturated carboxylic acid esters having no reactive functional group as monomer units Acrylic copolymer (A) having, isocyanate compound (B) having two or more isocyanate groups in one molecule, and at least general formula (1)

And an epoxy compound (C) having at least one repeating unit represented by the formula:

  Moreover, the coating agent composition of this invention is 1-20 mass parts of said isocyanate compounds (B), and 0 of epoxy compounds (C) with respect to 30 mass parts of said acrylic copolymers (A) in the said invention. 0.1 to 15 parts by mass are included.

  The coating agent composition of the present invention is characterized in that, in the above invention, the epoxy compound (C) is an epichlorohydrin adduct of a polyhydric alcohol.

  Moreover, the coating agent composition of the present invention is the above invention, wherein the epoxy compound (C) is an epichlorohydrin adduct of a polyhydric alcohol having a repeating unit represented by the general formula (1), It is a mixture with an epichlorohydrin adduct of a polyhydric alcohol having no repeating unit represented by the general formula (1).

  Moreover, the back surface protection sheet for solar cells of this invention is a back surface protection sheet for solar cells which has a base film which consists of at least 1 layer, and a coating layer which consists of at least 1 layer formed in the at least single side | surface of this base film. And the said coat layer hardens | cures the coating agent composition as described in any one of the above, It is characterized by the above-mentioned.

  Moreover, the back surface protection sheet for solar cells of this invention is the said invention, The said base film consists of polyester-type resin, It is characterized by the above-mentioned.

で表される繰り返し単位を１以上有するエポキシ化合物（Ｃ）と、を含むコーティング剤組成物を硬化してなることを特徴とする。 Moreover, the back surface protection sheet for solar cells of this invention is the surface which contact | connects the base film which consists of at least 1 layer, the aluminum foil arrange | positioned at the one side or both sides of this base film, and the said base film of this aluminum foil And at least one coat layer composed of at least one layer disposed on the back side, wherein the coat layer is a radically polymerizable unsaturated carboxylic acid, a hydroxyl group, or a radical having an epoxy ring. One or more compounds (A-1) selected from the group consisting of polymerizable unsaturated carboxylic acid esters and one type selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group An acrylic copolymer (A) having the above compound (A-2) as a monomer unit, and two or more isocyanate groups in one molecule. Isocyanate compounds (B), and at least the general formula (1)

It is characterized by curing a coating agent composition comprising an epoxy compound (C) having at least one repeating unit represented by the formula:

  Moreover, the back surface protection sheet for solar cells of this invention is the said invention. WHEREIN: The said coating layer is 1-20 mass parts of said isocyanate compounds (B) with respect to 30 mass parts of said acrylic copolymers (A), The epoxy compound (C) is formed from a coating agent composition containing 0.1 to 5.0 parts by mass.

  Moreover, the back surface protection sheet for solar cells of the present invention is characterized in that, in the above invention, the epoxy compound (C) is an epichlorohydrin adduct of a polyhydric alcohol.

  Moreover, the back surface protection sheet for solar cells of this invention WHEREIN: The said epoxy compound (C) is the epichlorohydrin adduct of the polyhydric alcohol which has a repeating unit represented by said General formula (1). And an epichlorohydrin adduct of a polyhydric alcohol having no repeating unit represented by the general formula (1).

  Moreover, the back surface protection sheet for solar cells of this invention is the said invention, The said coating layer contains a pigment, It is characterized by the above-mentioned.

  Moreover, the back surface protection sheet for solar cells of this invention is the said invention, The thickness of the said aluminum foil is 9-30 micrometers, It is characterized by the above-mentioned.

で表される繰り返し単位を１以上有するエポキシ化合物（Ｃ）と、を混合する接着剤組成物を硬化してなることを特徴とする。 Moreover, the back surface protection sheet for solar cells of this invention is the 1st base film which consists of at least 1 layer, the aluminum foil or 2nd base film which are arrange | positioned at least on one side of this 1st base film, 1 a base film and an adhesive for adhering the aluminum foil or the second base film, the back surface protective sheet for solar cells, wherein the adhesive is a radically polymerizable unsaturated carboxylic acid or a hydroxyl group or One or more compounds (A-1) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having an epoxy ring, and a group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group An acrylic copolymer (A) having one or more selected compounds (A-2) as monomer units, and two or more isocyanates in one molecule Isocyanate compound having a sulfonate group (B), and at least the general formula (1)

It is characterized by curing an adhesive composition that mixes with an epoxy compound (C) having at least one repeating unit represented by the formula:

  Moreover, the back surface protection sheet for solar cells of this invention WHEREIN: When the said 1st base film and the said aluminum foil are adhere | attached in the said invention, the said adhesive agent is 30 mass parts of said acrylic copolymers (A). On the other hand, the isocyanate compound (B) contains 1 to 20 parts by mass and the epoxy compound (C) contains 0.1 to 5.0 parts by mass.

  Moreover, the back surface protection sheet for solar cells of this invention is the said invention WHEREIN: A said 2nd base film is a base film which has an inorganic oxide vapor deposition layer, or a colored base film.

  Moreover, when the back surface protection sheet for solar cells of this invention adhere | attaches the said 1st base film and the said 2nd base film in the said invention, the said adhesive agent is the said acrylic copolymer (A). 1 to 20 parts by mass of the isocyanate compound (B) and 0.1 to 15.0 parts by mass of the epoxy compound (C) with respect to 30 parts by mass.

  Moreover, the back surface protection sheet for solar cells of the present invention is characterized in that, in the above invention, the epoxy compound (C) is an epichlorohydrin adduct of a polyhydric alcohol.

  Moreover, the back surface protection sheet for solar cells of this invention WHEREIN: The said epoxy compound (C) is the epichlorohydrin adduct of the polyhydric alcohol which has a repeating unit represented by said General formula (1). And an epichlorohydrin adduct of a polyhydric alcohol having no repeating unit represented by the general formula (1).

  Moreover, the back surface protection sheet for solar cells of this invention is the said invention, The said adhesive agent contains a pigment (D), It is characterized by the above-mentioned.

  Moreover, the back surface protection sheet for solar cells of this invention is the above-mentioned invention. The 1st base film which consists of at least 1 layer, The aluminum foil arrange | positioned at least on one side of this 1st base film, An adhesive that bonds the second base material disposed on the back surface of the surface on which the first base material is disposed, the first base film and the aluminum foil, and the aluminum foil and the second base film. It is characterized by having.

  The coating agent composition and the back surface protective sheet for solar cells according to the present invention have excellent water vapor barrier properties and design properties, and have high adhesion between the coating layer and the base film, and are excellent in long-term moist heat aging resistance. There is an effect.

FIG. 1 is a cross-sectional view showing a configuration of a solar cell back surface protective sheet according to Embodiment 2 of the present invention. FIG. 2 is a cross-sectional view showing a configuration of a back protective sheet for a solar cell according to Modification 1 of Embodiment 2 of the present invention. FIG. 3 is a cross-sectional view showing a configuration of a solar cell back surface protective sheet according to Modification 2 of Embodiment 2 of the present invention. FIG. 4 is a cross-sectional configuration diagram illustrating an example of a solar cell back surface protective sheet according to Embodiment 3 of the present invention. FIG. 5: is sectional drawing which shows the structure of the back surface protection sheet for solar cells which concerns on the modification 1 of Embodiment 3 of this invention. FIG. 6: is sectional drawing which shows the structure of the back surface protection sheet for solar cells which concerns on the modification 2 of Embodiment 3 of this invention. FIG. 7: is sectional drawing which shows the structure of the back surface protection sheet for solar cells which concerns on Embodiment 4 of this invention. FIG. 8: is sectional drawing which shows the structure of the back surface protection sheet for solar cells which concerns on the modification 1 of Embodiment 4 of this invention. FIG. 9: is sectional drawing which shows the structure of the back surface protection sheet for solar cells which concerns on the modification 2 of Embodiment 4 of this invention. FIG. 10: is sectional drawing which shows the structure of the back surface protection sheet for solar cells which concerns on the modification 3 of Embodiment 4 of this invention. FIG. 11: is sectional drawing which shows the structure of the back surface protection sheet for solar cells which concerns on the modification 4 of Embodiment 4 of this invention.

  EMBODIMENT OF THE INVENTION Below, embodiment of the back surface protection sheet for solar cells provided with the coating agent composition concerning this invention and the coating layer formed from this coating agent composition is described in detail based on drawing. In addition, this invention is not limited to these embodiment, A various change is possible in the range which does not deviate from the summary of this invention.

(Embodiment 1)
The coating agent composition concerning Embodiment 1 of this invention is 1 or more types of compounds selected from the group which consists of radically polymerizable unsaturated carboxylic acid and radically polymerizable unsaturated carboxylic acid ester which has a hydroxyl group or an epoxy ring ( A-1), and an acrylic copolymer (A) having, as a monomer unit, one or more compounds (A-2) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group ), An isocyanate compound (B) having two or more isocyanate groups in one molecule, and at least the general formula (1)

で表される繰り返し単位を１以上有するエポキシ化合物（Ｃ）と、を混合することを特徴とする。また、本発明の実施の形態１にかかるコーティング剤組成物により形成される塗膜は、太陽電池の裏面保護シートに加え、高温高湿下で劣化しやすいプラスチック製品の塗膜として用いることを目的とするため、高温高湿下での耐久性（本明細書では、以下「耐湿熱性」という）を備えていることが好ましい。耐湿熱性は、例えば、ＪＩＳ Ｃ８９１７−１９９８、ＪＩＳ Ｃ８９３８−１９９５、ＪＩＳ Ｃ８９９０ １０．１３等により評価することができる。

And an epoxy compound (C) having at least one repeating unit represented by the formula: Moreover, the coating film formed with the coating agent composition concerning Embodiment 1 of this invention aims at using it as a coating film of the plastic product which deteriorates easily under high temperature and high humidity in addition to the back surface protection sheet of a solar cell. Therefore, it is preferable to have durability under high temperature and high humidity (hereinafter referred to as “moisture and heat resistance”). The wet heat resistance can be evaluated by, for example, JIS C8917-1998, JIS C8938-1995, JIS C8990 10.13, and the like.

  First, the acrylic copolymer (A) used for the coating agent composition of Embodiment 1 is demonstrated. As described above, the acrylic copolymer (A) of the present invention is one selected from the group consisting of radically polymerizable unsaturated carboxylic acids and radically polymerizable unsaturated carboxylic esters having a hydroxyl group or an epoxy ring. It has as a monomer unit the above compound (A-1) and one or more compounds (A-2) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group.

  The radical polymerizable unsaturated carboxylic acid which is a monomer unit of the acrylic copolymer (A) means a carboxylic acid having a double bond at the α-position, and a radical polymerizable unsaturated carboxylic acid having a hydroxyl group or an epoxy ring. The ester (A-1) means an ester of a carboxylic acid having a double bond at the α-position and an alcohol, and having a hydroxyl group or an epoxy ring. A radical polymerizable unsaturated carboxylic acid that reacts with an isocyanate compound (B) and / or an epoxy compound (C) described later, or an ester of a radical polymerizable unsaturated carboxylic acid and a polyhydric alcohol is preferable. The polyhydric alcohol may be glycidyl alcohol added with epichlorohydrin. Since the radically polymerizable unsaturated carboxylic acid of the present invention or the radically polymerizable unsaturated carboxylic acid ester (A-1) having a hydroxyl group or an epoxy ring has a reactive hydroxyl group, a carboxyl group or an epoxy ring, the isocyanate described later is used. It can react with the compound (B) and / or the epoxy compound (C) to form a crosslinked structure. The component (A-1) may contain at least one radical polymerizable unsaturated carboxylic acid or one or more radical polymerizable unsaturated carboxylic acid ester having a hydroxyl group or an epoxy ring, and may be a mixture of two or more kinds. Good.

  Examples of the radical polymerizable unsaturated carboxylic acid or the radical polymerizable unsaturated carboxylic acid ester (A-1) having a hydroxyl group or an epoxy ring include (meth) acrylic acid, itaconic acid, maleic acid, crotonic acid, and tiglic acid. , Cinnamic acid, (meth) acrylic acid-1-hydroxyethyl, (meth) acrylic acid-2-hydroxyethyl, (meth) acrylic acid-1-hydroxypropyl, (meth) acrylic acid-2-hydroxypropyl, (meta ) Acrylic acid-1-hydroxybutyl and glycidyl methacrylate are exemplified. Moreover, 4-hydroxybutyl acrylate glycidyl ether is illustrated as ester of the glycidyl alcohol which added the epichlorohydrin to the polyhydric alcohol, and radically polymerizable unsaturated carboxylic acid, for example. Furthermore, an adduct of hydroxyethyl (meth) acrylate and ε-caprolactone can also be suitably used. It is also possible to use allyl alcohol or methacryl alcohol. Further, (A-1) according to the first embodiment includes an isocyanate compound (B) described later in addition to a hydroxyl group, a carboxyl group or an epoxy ring that reacts with the isocyanate compound (B) and / or the epoxy compound (C) described later. And / or a functional group that does not react with the epoxy compound (C), for example, an amide group, a methylol group, a carbonyl group, or an amino group. In the present specification, (meth) acrylic acid means methacrylic acid and / or acrylic acid.

  Further, the radical polymerizable unsaturated carboxylic acid ester (A-2) having no reactive functional group has a reactive functional group that reacts with an isocyanate compound (B) and / or an epoxy compound (C) described later. A carboxylic acid ester that does not have a double bond at the α-position of the carboxylic acid. The radical polymerizable unsaturated carboxylic acid ester (A-2) having no reactive functional group is preferably an ester of an alcohol having an alicyclic hydrocarbon group and a radical polymerizable unsaturated carboxylic acid.

  Examples of the radical polymerizable unsaturated carboxylic acid ester (A-2) having no reactive functional group include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylate-n-propyl, ( (Meth) acrylic acid isopropyl, (meth) acrylic acid-n-butyl, (meth) acrylic acid isobutyl, (meth) acrylic acid-t-butyl, (meth) acrylic acid-2-ethylhexyl, lauryl methacrylate, phenyl acrylate , (Meth) acrylic acid isobornyl, methacrylic acid cyclohexyl, (meth) acrylic acid-t-butylcyclohexyl, (meth) acrylic acid dicyclopentadienyl, (meth) acrylic acid dihydrodicyclopentadienyl, etc. . It preferably contains isobornyl (meth) acrylate, cyclohexyl methacrylate, (meth) acrylic acid-t-butylcyclohexyl, (meth) acrylic acid dicyclopentadienyl, (meth) acrylic acid dihydrodicyclopentadienyl. The radical polymerization (A-2) component only needs to contain one or more radically polymerizable unsaturated carboxylic acid esters having no reactive functional group, and may be a mixture of two or more. The component (A-2) preferably contains an ester of an alcohol having an alicyclic hydrocarbon group and a radically polymerizable unsaturated carboxylic acid.

  The acrylic copolymer (A) of Embodiment 1 is one or more compounds selected from the group consisting of radically polymerizable unsaturated carboxylic acids and radically polymerizable unsaturated carboxylic acid esters having a hydroxyl group or an epoxy ring 0.1 to 10 parts by mass of (A-1) and 60 to 99 of one or more compounds (A-2) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group. It is preferably blended and polymerized in a ratio of 9 parts by mass, and one or more selected from the group consisting of radically polymerizable unsaturated carboxylic acid and radically polymerizable unsaturated carboxylic acid ester having a hydroxyl group or an epoxy ring 1 to 5.0 parts by mass of the compound (A-1), selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group Preceding compound (A-2) particularly preferable to be 80 to 99 parts by weight.

  In addition, the acrylic copolymer (A) of Embodiment 1 is one or more selected from the group consisting of a radical polymerizable unsaturated carboxylic acid and a radical polymerizable unsaturated carboxylic acid ester having a hydroxyl group or an epoxy ring. Compound (A-1), one or more compounds (A-2) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group, and a metal having a reactive functional group A polymer obtained by polymerizing or polymerizing and cross-linking alkoxide (A-3) can also be suitably used. By using the acrylic copolymer (A) containing the metal alkoxide (A-3) having a reactive functional group, the water resistance when the coating composition of Embodiment 1 is used as a coating film is improved. be able to.

The metal alkoxide having a reactive functional group or a carbon-carbon double bond is a general formula: YM (OR) ₃ , YRM (OR) ₂ , Y ₂ M (OR) ₂ , YR ₂ M (OR), YM ( OR) ₂ , YRM (OR), Y ₂ M (OR) (wherein M is a metal such as silicon, aluminum or titanium, R is an alkyl group, Y is a reactive functional group or a carbon-carbon double bond) Y is a functional group selected from the group consisting of an alkenyl group, a (meth) acryloalkyl group, a mercaptoalkyl group, an acylthio group, an aminoalkyl group, a ureido group, and an isocyanate group. In the case of having R, R may be the same or different.

  As the metal alkoxide having such a reactive functional group, a metal alkoxide containing silicon is particularly preferable. For example, vinyltriisopropoxysilane, allyltrimethoxysilane, diallyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3- Methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-mercaptopropyltriethoxysilane, 3-octainoylthio-1-propyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyl Trimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxy Examples include silane, 3-isocyanatopropyltriethoxysilane, and 3-isocyanatepropyltrimethoxysilane.

  In addition to the metal alkoxide having a reactive functional group that reacts with the component (A-1), tetraalkoxysilane, trialkoxyaluminum, tetraalkoxytitanium, and the like may be added.

  The acrylic copolymer (A) containing the metal alkoxide (A-3) according to Embodiment 1 comprises a radical polymerizable unsaturated carboxylic acid and a radical polymerizable unsaturated carboxylic acid ester having a hydroxyl group or an epoxy ring. One or more compounds (A-1) selected from the group and one or more compounds (A-2) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group; The metal alkoxide (A-3) having a reactive functional group may be blended and polymerized at a predetermined ratio.

  The acrylic copolymer (A) containing the metal alkoxide (A-3) according to Embodiment 1 comprises a radical polymerizable unsaturated carboxylic acid and a radical polymerizable unsaturated carboxylic acid ester having a hydroxyl group or an epoxy ring. One or more compounds (A-1) selected from the group and one or more compounds (A-2) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group; Are mixed in the above-mentioned proportions, and 100 parts by mass of the polymerized acrylic copolymer (AP) (including a semipolymer) is added with a metal alkoxide (A-3) having a reactive functional group in an amount of 0. A compound obtained by blending at a ratio of 1 to 10 parts by mass and polymerizing is preferable, and a metal alkoxy having a reactive functional group with respect to 100 parts by mass of an acrylic copolymer (AP) (including a semipolymer). (A-3) particularly preferably in a proportion of 0.1 to 2 parts by weight.

  In addition, the acrylic copolymer (A) of Embodiment 1 is one or more selected from the group consisting of a radical polymerizable unsaturated carboxylic acid and a radical polymerizable unsaturated carboxylic acid ester having a hydroxyl group or an epoxy ring. Compound (A-1), one or more compounds (A-2) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group, and an isocyanate compound (B) to be described later And / or a monomer component (A-4) containing a functional group that does not react with the epoxy compound (C) may be polymerized. Furthermore, it has one or more compounds (A-1) selected from the group consisting of radically polymerizable unsaturated carboxylic acids and radically polymerizable unsaturated carboxylic acid esters having a hydroxyl group or an epoxy ring, and a reactive functional group. One or more compounds (A-2) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters, a metal alkoxide (A-3) having a reactive functional group, and an isocyanate compound (B) described later And / or a monomer component (A-4) containing a functional group that does not react with the epoxy compound (C) may be polymerized or polymerized and crosslinked. The monomer component (A-4) is a compound having an unsaturated bond, and examples thereof include polymerizable aromatic compounds such as styrene, α-methylstyrene, vinyl ketone, t-butylstyrene, parachlorostyrene and vinylnaphthalene, and acrylonitrile. Examples thereof include polymerizable nitriles such as methacrylonitrile, α-olefins such as ethylene and propylene, vinyl esters such as vinyl acetate and vinyl propionate, and dienes such as butadiene and isoprene.

  As the acrylic copolymer (A) according to the first embodiment, an acrylic copolymer (A) emulsified in an aqueous solvent, a resin solution dissolved in a non-aqueous solvent, or the like can be used. Examples of the acrylic copolymer (A) according to the present invention include, for example, JP-A-07-233208, JP-A-05-230116, JP-A-2003-192981, JP-A-05-039328, JP-A-06-116311. Can be produced by the methods described in JP-A Nos. 05-39328 and 05-255411.

  In the polymerization of the acrylic copolymer (A) according to the first embodiment, for example, azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis ( 2- (2-imidazolin-2-yl) propane) and 2,2′-azobis (2,4-dimethylvaleronitrile) and other azo oily compounds, anionic 4,4′-azobis (4-cyano) Aqueous compounds such as valeric acid), 2,2-azobis (N- (2-carboxyethyl) -2-methylpropionamidine) and cationic 2,2′-azobis (2-methylpropionamidine), benzoyl peroxide Redox oily peroxides such as parachlorobenzoyl peroxide, lauroyl peroxide and t-butyl perbenzoate, potassium persulfate Beam, such as sodium persulfate and ammonium persulfate may be used aqueous peroxide as a polymerization initiator.

  Moreover, it is preferable to perform emulsion polymerization using an emulsifier when the acrylic copolymer (A) according to the first embodiment is polymerized. As an emulsifier, in addition to an anionic emulsifier and a nonionic emulsifier, a reactive emulsifier can also be used.

  Further, in order to adjust the molecular weight of the acrylic copolymer (A) according to the first embodiment, a mercaptan such as lauryl mercaptan and a chain transfer agent such as α-methylstyrene dimer are used as necessary. May be.

  The polymerization reaction temperature of the mixed monomer is determined by the initiator. For example, it is preferably 60 to 90 ° C. when a persulfuric acid initiator is used, and preferably 30 to 70 ° C. when a redox initiator is used. . The amount of the initiator used is generally 0.1 to 3% by mass, preferably 0.2 to 1% by mass, based on the total amount of monomers.

  One or more compounds (A-1) selected from the group consisting of radically polymerizable unsaturated carboxylic acids and radically polymerizable unsaturated carboxylic acid esters having a hydroxyl group or an epoxy ring, and radicals having no reactive functional group The average particle diameter of the polymer resin particles obtained by polymerizing one or more compounds (A-2) selected from the group consisting of polymerizable unsaturated carboxylic acid esters is 0.03 to 0.70 μm. A range is preferable.

  The polymer resin particles have a mass average molecular weight of 10,000 to 2,500,000, more preferably 50,000 to 2,000,000, and particularly preferably 100,000 to 1,500,000. preferable.

  In the emulsion having the above composition, the resin solid content is preferably 30 to 65% by mass.

  Subsequently, a method for preparing an acrylic copolymer (A) resin solution using a non-aqueous solvent will be described. As the non-aqueous solvent, an organic solvent such as toluene or ethyl acetate is used. As the non-aqueous solvent, xylene, N-methylpyrrolidone, butyl acetate, aliphatic and / or aromatic having a relatively high boiling point, butyl diglycol acetate, acetone, and the like can be appropriately used.

  Moreover, as a polymerization initiator, an initiator (azo-based or peroxide-based) that generates radicals is used.

  All the monomers constituting the acrylic copolymer (A) or a part of the monomers and the polymerization initiator are dissolved in the non-aqueous solvent to prepare a resin solution for polymerization or partial polymerization (semi-polymerization). obtain. The concentration of the resin component in the resin solution is preferably 30 to 50% by mass.

  In the emulsion and resin solution containing the acrylic copolymer (A), a pigment may be further mixed with the resin component and the solvent. As the pigment, a color pigment for coloring the coating agent composition and an extender pigment can be used. By adding the above pigment to the coating composition, the amount of ultraviolet light that passes through the coating film can be reduced, so that deterioration of the substrate can be suppressed and weather resistance can be improved. Color pigments are excellent in the effect of suppressing ultraviolet light transmission. Examples of coloring pigments include titanium oxide, cadmium red, red rice, toluidine red, yellow lead, iron yellow, titanium yellow, fast yellow, anthraquinone yellow, benzidine yellow, chromium oxide, phthalocyanine green, bitumen, ultramarine blue, and phthalon cyanine blue. And carbon black, iron black, graphite and the like. Inorganic color pigments such as titanium oxide, red pepper, iron yellow, and carbon black are preferably used because of excellent weather resistance. Among these, titanium oxide is particularly preferable.

  The coloring pigment is preferably blended in an amount of 5 to 60 parts by weight, more preferably 10 to 50 parts by weight, particularly 20 to 40 parts by weight, based on 100 parts by weight of the acrylic copolymer (A). preferable. When the blending amount of the color pigment is small, it is difficult to obtain the effect of suppressing the transmission of ultraviolet rays, and when it is too large, the hot water resistance and the heat and humidity resistance are lowered. Since carbon black is difficult to disperse in the coating agent composition, it is preferably used in combination with other inorganic color pigments. When carbon black and an inorganic color pigment are used in combination, 1 to 20 parts by mass, preferably 2 to 15 parts by mass of carbon black is added to 100 parts by mass of the inorganic color pigment. The inorganic coloring pigment is preferably titanium oxide. Moreover, when using an organic coloring pigment, it is preferable to use together with an inorganic coloring pigment from a viewpoint of the ultraviolet protection of a base material, and 1-100 mass of organic coloring pigments with respect to 100 mass parts of inorganic coloring pigments. In part, preferably 2 to 60 parts by mass, it is possible to suppress the transmission of ultraviolet rays over a long period of time.

  The extender pigment is less effective in suppressing the transmission of ultraviolet rays than the colored pigment, but is effective in preventing blocking and reducing pinholes (small holes due to coating agent bubbles and repellency of the coating agent due to the substrate). Examples of extender pigments include calcium carbonate, talc, kaolin clay, calcium oxide, resin beads, barium sulfate, barium carbonate, gypsum, silica, white carbon, diatomaceous earth, magnesium carbonate, aluminum hydroxide, and magnesium oxide. . The extender pigment is preferably blended in an amount of 1 to 30 parts by weight, preferably 2 to 25 parts by weight, particularly preferably 3 to 20 parts by weight, based on 100 parts by weight of the acrylic copolymer (A). When using a color pigment and an extender pigment together, it is preferable to make it the compounding quantity of 60 mass parts or less with respect to 100 mass parts of acrylic copolymers (A) as the whole pigment. It is because hot water resistance and heat-and-moisture resistance fall when there are too many compounding quantities of a pigment.

  Moreover, you may mix an additive with the emulsion and resin solution containing the said acrylic copolymer (A) further as needed. Examples of the additives include surfactants such as dispersants and wetting agents, thickeners such as methylcellulose, hydroxyethylcellulose (HEC), polyacrylic acid, and bentonite, antifoaming agents, film-forming aids, antifreeze agents, and antiseptics. Examples include agents, antifungal agents, ultraviolet absorbers and the like.

  The colored pigment, extender pigment, and additive may be mixed with the acrylic copolymer (A), or may be mixed with an isocyanate compound (B) or an epoxy compound (C) described later.

  Next, the isocyanate compound (B) having two or more isocyanate groups in one molecule used in the coating agent composition of Embodiment 1 will be described.

  The isocyanate compound (B) concerning Embodiment 1 should just have 2 or more isocyanate groups in 1 molecule, and can use aromatic polyisocyanate, aliphatic polyisocyanate, etc.

  Examples of aromatic polyisocyanates include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (monomeric MDI), polymethylene polyphenylene polyisocyanate (polymeric MDI), tolidine diisocyanate (TODI), naphthalene diisocyanate (NDI), and xylylene diene. Aromatic alkyl polyisocyanates such as isocyanate (XDI) and tetramethyl-m-xylylene diisocyanate (TMXDI) are also included.

  Aliphatic polyisocyanates include hexamethylene diisocyanate (HDI), alicyclic alkyl polyisocyanates such as isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate (hydrogenated XDI), and dicyclohexylmethane diisocyanate (hydrogenated MDI). included.

  Hexamethylene diisocyanate is used as the polyisocyanate (B) of the first embodiment from the viewpoint of easy adjustment of the reaction rate when polymerizing or crosslinking the coating composition of the first embodiment and the flexibility of the coating film. Preferably used.

で表される繰り返し単位を１以上有する。また、エポキシ化合物（Ｃ）は、１分子中に２以上のエポキシ環を有するものが好ましい。 Then, the epoxy compound (C) used for the coating agent composition of Embodiment 1 is demonstrated. The epoxy compound (C) according to the present invention has at least the general formula (1).

It has 1 or more repeating units represented by. In addition, the epoxy compound (C) preferably has two or more epoxy rings in one molecule.

  The epoxy compound (C) according to Embodiment 1 is an epichlorohydrin adduct of a polyhydric alcohol obtained by a condensation reaction of a polyhydric alcohol and epichlorohydrin, and is represented by the above general formula (1). An epoxy compound having one or more repeating units is preferably used.

As the epoxy compound (C) of the present invention, a polyglycidyl ether of a glycerin / epichlorohydrin adduct represented by the following general formula (2):

Alternatively, polyglycidyl ether of an ethylene glycol / epichlorohydrin adduct represented by the following general formula (3) is preferably used.

  Furthermore, as the epoxy compound (C) of Embodiment 1, an epichlorohydrin adduct of a polyhydric alcohol having a repeating unit represented by the above general formula (1) and the above general formula (1) Particularly preferred are mixtures of polyhydric alcohols with epichlorohydrin adducts which do not have the repeating units represented.

  An epichlorohydrin adduct of a polyhydric alcohol having a repeating unit represented by the above general formula (1), and an epichlorohydric alcohol having no repeating unit represented by the above general formula (1) As a mixture with a hydrin adduct, for example, a polyglycidyl ether of a glycerin / epichlorohydrin adduct represented by the above general formula (2) and an epoxy having n = 0 in the above general formula (2) A mixture with a compound is exemplified.

  Furthermore, a mixture of the polyglycidyl ether of the ethylene glycol / epichlorohydrin adduct represented by the general formula (3) and the epoxy compound in which n = 0 in the general formula (3) is also preferably used. The

  The coating agent composition concerning Embodiment 1 is 1-20 mass parts of isocyanate compounds (B) which have 2 or more isocyanate groups in 1 molecule with respect to 30 mass parts of acrylic copolymers (A), It is preferable to blend 0.1 to 15 parts by mass of the epoxy compound (C) having two or more epoxy rings in one molecule. More preferably, with respect to 30 parts by mass of the acrylic copolymer (A), 2 to 15 parts by mass of an isocyanate compound (B) having two or more isocyanate groups in one molecule is used. 1 to 13 parts by mass of an epoxy compound (C) having an epoxy ring is added, and 3 to 10 parts by mass of an isocyanate compound (B) having two or more isocyanate groups in one molecule is contained in one molecule. It is preferable to blend 3 to 10 parts by mass of the epoxy compound (C) having two or more epoxy rings. This is because if the amount of the isocyanate compound (B) is less than 1 part by mass, the desired degree of adhesiveness cannot be obtained, and if it is more than 20 parts by mass, a decrease in weather resistance is observed. Further, when the amount of the epoxy compound (C) is less than 0.1 parts by mass, the desired degree of hot water resistance cannot be obtained, and when it is more than 15 parts by mass, the coating film becomes sticky and easily becomes dirty. In addition, when the product on which the coated film after production is formed is stored or transported, there is a risk that blocking may occur where the products stick to each other due to the adhesiveness of the coated film.

  Also, one type selected from the group consisting of radically polymerizable unsaturated carboxylic acids and radically polymerizable unsaturated carboxylic acid esters having a hydroxyl group or an epoxy ring, which are constituents of the coating agent composition according to the first embodiment An acrylic copolymer having as a monomer unit the above compound (A-1) and one or more compounds (A-2) selected from the group consisting of radically polymerizable unsaturated carboxylic acids having no reactive functional group. An emulsion or resin solution containing the polymer (A), an isocyanate compound (B) having two or more isocyanate groups in one molecule, and an epoxy compound having a repeating unit represented by the general formula (1) ( C) are mixed at a predetermined ratio, applied onto a substrate, and then allowed to stand for a predetermined time and dried to remove the aqueous solvent or non-aqueous solvent. Accordingly, it is possible to form a coating film.

  The base material on which the coating film is formed is made of plastic, for example, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin resins such as polyethylene and polypropylene, polystyrene, polyamide, polycarbonate, Those formed from polyacrylonitrile, polyimide or the like are preferred. When the substrate is a polyester resin, it is preferable because high adhesiveness can be obtained. As the shape of the base material, a film shape, a sheet shape, a plate shape, a block shape or the like is preferably selected.

  The coating agent composition of Embodiment 1 is applied to one or both sides of the substrate so that the thickness of the coating film after drying is 6 to 350 μm. As a coating method of the coating agent composition, conventionally known means such as a dipping method, a roll coating method, a screen printing method, a spray method and the like that are generally used can be used. In order to uniformly control the thickness, a plurality of thin coating layers may be laminated to have a predetermined film thickness. In the case of multiple layers, it is repeated that after the previously applied layer is dried, the next layer is applied, the layer is dried, and then the next layer is applied.

  In the coating film formed from the coating agent composition of Embodiment 1, the acrylic copolymer (A) is a composition crosslinked with an isocyanate compound (B) and an epoxy compound (C). In the acrylic copolymer (A), two or more kinds of acrylic monomers are combined in a chain shape, and flexibility is maintained by the chain of the formed acrylic copolymer (A). In the chain acrylic copolymer (A), a plurality of hydroxyl groups, carboxyl groups, or epoxy rings derived from the component (A-1) are interspersed at intervals, and the hydroxyl groups, carboxyl groups Alternatively, the epoxy ring reacts with the isocyanate group of the isocyanate compound (B) or the epoxy ring of the epoxy compound (C) to form a bond. In addition, since the isocyanate compound (B) and the epoxy compound (C) have two or more reactive isocyanate groups and epoxy rings in one molecule, two or more isocyanate groups and epoxy rings react, The acrylic copolymer (A) forms a network structure. This network structure can realize flexibility and high moisture and heat resistance.

  Furthermore, the coating film formed from the coating composition of Embodiment 1 has an isocyanate group of the isocyanate compound (B), an epoxy ring of the epoxy compound (C), and a reactive functional group of the metal alkoxide (A-3). Therefore, the adhesion to the plastic substrate is good, and the adhesion to the polyester is particularly good.

  From the above, the coating composition according to Embodiment 1 is used as a coating layer for a solar cell backsheet described later, and also has a coating property having weather resistance, moist heat resistance, and excellent adhesion to a substrate. In order to form a film, it can also be suitably used as a coating layer for protective sheets, electronic circuit boards, bathrooms (unit baths), articles and devices used around the water in bathrooms and toilets.

(Embodiment 2)
The back surface protection sheet for solar cells concerning Embodiment 2 of this invention has a base film which consists of at least 1 layer, and a solar cell which has a coat layer which consists of at least 1 layer formed in the at least single side | surface of the said base film. It is a back surface protection sheet. The coat layer is formed by curing the coating agent composition of Embodiment 1. When the back surface protection sheet for solar cells according to Embodiment 2 is incorporated into a solar cell module, the coat layer is positioned outside the base film.

  FIG. 1 is a cross-sectional view showing a configuration of a solar cell back surface protective sheet according to Embodiment 2 of the present invention. In the back surface protection sheet 10 for a solar cell in FIG. 1, the base film 1 has a single layer structure, and shows a case of a laminated structure in which a coat layer 2 having a single layer structure is formed. The solar cell back surface protective sheet 10 of Embodiment 2 is one embodiment of FIG. 1 as long as it has at least the coat layer 2 positioned outside the base film when used as a protective sheet. In addition to the form, a configuration having a laminated structure as shown in FIGS.

  FIG. 2 is a cross-sectional view showing a configuration of a back protective sheet for a solar cell according to Modification 1 of Embodiment 2 of the present invention. The back surface protection sheet 10A for solar cells in FIG. 2 includes a first base film 1a and a second base film 1b, and has a laminated structure in which a single layer coat layer 2 is formed on the second base film 1b side. Shows the case. In addition, the 1st base film 1a and the 2nd base film 1b are adhere | attached with the adhesive agent 3. FIG.

  Moreover, FIG. 3 is sectional drawing which shows the structure of the back surface protection sheet for solar cells which concerns on the modification 2 of Embodiment 2 of this invention. The back surface protection sheet 10B for solar cells of FIG. 3 has shown the case of the laminated structure which each formed the coating layer 2 of 1 layer structure on the both sides of the base film 1 of 1 layer structure.

  Hereinafter, each component will be described with reference to the drawings. In the following drawings, description will be made with reference to FIG. 1 as a representative, but the description contents are the same in the modified examples of FIG. 2 and FIG.

(Base film)
The base film 1 according to the second embodiment will be described. As the base film 1, a resin film that can be molded and processed within a range that does not melt and soften while being appropriately adjusted within a predetermined heating time because it is heated in a hot press when forming a solar cell module is used. it can. Examples of the material of the base film 1 include at least one selected from polyester resins, polyolefin resins, polystyrene resins, polyamide resins, polycarbonate resins, and polyacrylonitrile resins. In other words, examples of the base film 1 include polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), including low oligomer types, polyethylene (LDPE, LLDPE, HDPE), polypropylene, and the like. Engineering plastic films such as polyolefin film, polystyrene film, polyamide film, polycarbonate film, polyacrylonitrile film and polyimide film are used. The material of the base film 1 is preferably a polyester film. The thickness of the base film 1 is in the range of 3 to 300 μm.

  The base film 1 is preferably such that the surface is oxidized by irradiation treatment or flame treatment using oxygen plasma or corona discharge. By oxidizing the surface, many functional groups are present on the surface. A film rich in functional groups on the surface tends to have better adhesion to the silane-based adhesive and the coat layer 2 used when the base film 1 is laminated in multiple layers. Therefore, it is preferable to use a film that has been appropriately surface-treated as the base film 1.

  Moreover, the film used as the base film 1 may be one in which an inorganic oxide is deposited on the surface thereof. In the present invention, when the base film 1 has a multi-layer structure (for example, see FIG. 2), the required gas barrier property is improved by forming at least one of the films with an inorganic oxide vapor deposition film. can do. Moreover, when bonding a film with a vapor deposition film, it is preferable to bond a vapor deposition surface to the PET surface which does not have a vapor deposition film.

  As the inorganic oxide for vapor deposition, silicon oxide, aluminum oxide, zinc oxide, or the like can be used, and the vapor deposition thickness is preferably 1 nm to 100 nm.

  As shown in FIG. 2, as the adhesive composition used when the first base film 1a and the second base film 1b having a multilayer structure are bonded together, silane-based, urethane-based, acrylic-based, epoxy-based, silicon-based Each of the adhesive compositions can be used. Among them, the silane-based adhesive composition is preferable because it has excellent adhesive performance even under high temperature and high humidity.

  As used herein, the silane-based adhesive composition is a coating composition containing a metal alkoxide (A-3) having a reactive functional group according to the first embodiment in addition to a conventional silane coupling agent. Can do.

  In the silane-based adhesive composition, the alkoxy group of alkoxysilane is hydrolyzed to produce a silanol group (Si-OH), and this silanol group is a carboxyl group oxidized by oxygen plasma or corona discharge on the film surface. Since it reacts and bonds with hydroxyl groups, the adhesion between films is good. Further, since hydrolysis does not occur even under high temperature and high humidity, it has excellent weather resistance because of good adhesive properties and a strong silanol bond against UV energy.

  When the base film 1 is composed of two or more layers bonded with a silane-based adhesive composition, the combination structure includes the same type of film, different types of film, Any combination of the same film with an inorganic oxide deposited on one side and between different films with an inorganic oxide deposited on one side may be used.

  As the coating agent composition for forming the coating layer 2 according to the second embodiment, the coating agent composition according to the first embodiment of the present invention can be used.

  The solar cell back surface protective sheet 10 according to the second exemplary embodiment of the present invention is made of a radical polymerizable unsaturated carboxylic acid ester having a radical polymerizable unsaturated carboxylic acid or a hydroxyl group or an epoxy ring on the base film 1. One or more selected compounds (A-1) and one or more compounds (A-2) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group are monomer units. An emulsion or resin solution containing the acrylic copolymer (A) as an isocyanate compound (B) having two or more isocyanate groups in one molecule, and a repeating unit represented by the general formula (1) A coating agent composition in which an epoxy compound (C) having at least 1 is mixed at a predetermined ratio is applied, left to stand for a predetermined time, and dried. Forming a coating layer 2 by removing the system solvent or non-aqueous solvent.

  Or the back surface protection sheet 10 for solar cells concerning Embodiment 2 is selected from the group which consists of the radically polymerizable unsaturated carboxylic acid ester which has the radically polymerizable unsaturated carboxylic acid or a hydroxyl group, or an epoxy ring in the base film 1. One or more compounds (A-1) selected from the group consisting of one or more compounds (A-1) and a radical polymerizable unsaturated carboxylic acid ester having no reactive functional group, and reactivity An emulsion or resin solution containing an acrylic copolymer (A) having a functional group-containing metal alkoxide (A-3) as a monomer unit, and an isocyanate compound (B) having two or more isocyanate groups in one molecule And an epoxy compound (C) having one or more repeating units represented by the general formula (1) were mixed at a predetermined ratio. By applying a computing agent composition to form a coating layer 2 by removing the aqueous solvent or nonaqueous solvent and allowed to stand and dried for a predetermined time.

  The coating agent composition is applied to one side or both sides of the base film 1 so that the thickness of the coating layer 2 after drying is 6 to 350 μm. As a coating method of the coating agent composition, conventionally known means such as a dipping method, a roll coating method, a screen printing method, a spray method and the like that are generally used can be used. In order to uniformly control the thickness, a plurality of thin coating layers may be laminated to have a predetermined film thickness. In the case of multiple layers, it is repeated that after the previously applied layer is dried, the next layer is applied, the layer is dried, and then the next layer is applied.

  In the coat layer 2 of Embodiment 2, the acrylic copolymer (A) is a composition crosslinked with an isocyanate compound (B) and an epoxy compound (C). In the acrylic copolymer (A), two or more kinds of acrylic monomers are bonded in a chain form, and the flexibility is maintained by the formed acrylic copolymer chain. In the chain acrylic copolymer (A), a plurality of hydroxyl groups, carboxyl groups, or epoxy rings derived from the component (A-1) are interspersed at intervals, and the hydroxyl groups, carboxyl groups Alternatively, the epoxy ring reacts with the isocyanate group of the isocyanate compound (B) or the epoxy ring of the epoxy compound (C) to form a bond. In addition, since the isocyanate compound (B) and the epoxy compound (C) have two or more reactive isocyanate groups and epoxy rings in one molecule, two or more isocyanate groups and epoxy rings react, The acrylic copolymer (A) forms a network structure. This network structure can realize flexibility and high moisture and heat resistance.

  Furthermore, the coating layer 2 of Embodiment 2 is the base film 1 through the isocyanate group of the isocyanate compound (B), the epoxy ring of the epoxy compound (B), and the reactive functional group of the metal alkoxide (A-3). In particular, adhesion to a polyester substrate is good.

  From the above, the solar cell back surface protective sheet according to the second embodiment is excellent in moisture heat aging resistance, adhesiveness, and water vapor barrier properties. Moreover, the back surface protection sheet for solar cells according to the second embodiment can be used in a device that is relatively resistant to an external environment such as moisture, such as single crystal silicon or polycrystalline silicon, and uses a metal foil such as an aluminum foil. Therefore, it is excellent in cost reduction and weight reduction.

(Embodiment 3)
A solar cell back surface protective sheet according to Embodiment 3 of the present invention includes a base film composed of at least one layer, an aluminum foil disposed on one side or both sides of the base film, and the base material of the aluminum foil. A back protective sheet for a solar cell having at least one coat layer composed of at least one layer disposed on the back side of the surface in contact with the film, wherein the coat layer is a radically polymerizable unsaturated carboxylic acid, a hydroxyl group or One or more compounds (A-1) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having an epoxy ring, and a group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group An acrylic copolymer (A) having one or more selected compounds (A-2) as monomer units, and two or more compounds in one molecule; Isocyanate compound having an isocyanate group (B), and at least the following general formula (1)

で表される繰り返し単位を１以上有するエポキシ化合物（Ｃ）と、を混合したコーティング剤組成物を硬化してなることを特徴とし、本発明に係る太陽電池用裏面保護シートを太陽電池モジュールに組み込んだ際、該コート層は基材フィルムより外側に位置する。

The back surface protection sheet for solar cells according to the present invention is incorporated into a solar cell module, which is obtained by curing a coating agent composition obtained by mixing an epoxy compound (C) having at least one repeating unit represented by In this case, the coat layer is located outside the base film.

  FIG. 4: is sectional drawing which shows the structure of the back surface protection sheet for solar cells concerning Embodiment 3 of this invention. The back surface protection sheet 20 for a solar cell in FIG. 4 has a single-layer configuration of the base film 1, an aluminum foil 4 is disposed on one side of the base film 1, and a single-layer configuration is sandwiched between the aluminum foils 4. It has a laminated structure in which the coat layer 2 is formed. The base film 1 and the aluminum foil 4 are bonded with an adhesive 3. The solar cell back surface protective sheet 20 according to the third embodiment may have a stacked structure as shown in FIGS. 5 and 6 in addition to the embodiment shown in FIG. 4.

  FIG. 5: is sectional drawing which shows the structure of the back surface protection sheet for solar cells which concerns on the modification 1 of Embodiment 3 of this invention. 5A includes a first base film 1a and a second base film 1b, and an aluminum foil 4 is disposed on the first base film 1a side. The case of the laminated structure which formed the coating layer 2 of 1 layer structure in the back surface side of the surface where the base film 1a is arrange | positioned is shown. In addition, the 1st base film 1a and the 2nd base film 1b, the 1st base film 1a, and the aluminum foil 4 are adhere | attached with the adhesive agent 3, respectively.

  Moreover, FIG. 6 is a cross-sectional structure showing the configuration of the solar cell back surface protective sheet according to Modification 2 of Embodiment 3 of the present invention. The back surface protection sheet 20B for solar cells in FIG. 6 has an aluminum foil 4 disposed on one side of a base film 1 having a single layer structure, and a single layer structure on the back surface of the surface of the aluminum foil 4 on which the base film 1 is disposed. The case of the laminated structure in which the coat layer 2 is formed and the coat layer 2 is also formed on the side of the base film 1 where the aluminum foil 4 is not disposed is shown. The base film 1 and the aluminum foil 4 are bonded with an adhesive 3.

  Hereinafter, each component will be described with reference to the drawings. In the following drawings, description will be made with reference to FIG. 4 as a representative, but the description contents are the same in the modified examples of FIG. 5 and FIG.

  As the base film 1 concerning Embodiment 3, the thing similar to the base film 1 of Embodiment 2 can be used.

  As the aluminum foil 4 according to the third embodiment, one having a predetermined thickness capable of exhibiting a sufficient gas barrier property together with the coat layer 2 is used. The thickness of the aluminum foil 4 is adjusted depending on the thickness of the coat layer 2 and the presence or absence of the deposited film of the base material form 1, but a range of 9 to 50 μm is preferable. When the thickness is less than 9 μm, sufficient gas barrier properties cannot be exhibited. When the thickness is more than 50 μm, the aluminum foil 4 is adjacent to the aluminum foil 4 by the heat of about 150 ° C. applied to the sheet when the solar cell module is manufactured. This is because deformation may occur due to a difference in thermal expansion from the base film 1. The aluminum foil 4 is laminated on the base film 1 using a urethane-based adhesive composition.

(Coating agent composition)
The coating agent composition for forming the coat layer 2 according to the third embodiment will be described. As described above, the acrylic copolymer (A) used in the coating agent composition according to the third embodiment is a radical polymerizable unsaturated carboxylic acid or a radical polymerizable unsaturated carboxylic acid having a hydroxyl group or an epoxy ring. One or more compounds (A-1) selected from the group consisting of esters and one or more compounds (A-) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group And 2) as monomer units. One or more compounds (A-1) selected from the group consisting of radically polymerizable unsaturated carboxylic acids or radically polymerizable unsaturated carboxylic esters having a hydroxyl group or an epoxy ring, and radicals having no reactive functional group As the one or more compounds (A-2) selected from the group consisting of polymerizable unsaturated carboxylic acid esters, the same compounds as those in Embodiment 1 can be used.

  In addition, the acrylic copolymer (A) according to the third embodiment is a radical polymerizable unsaturated carboxylic acid or a radical polymerizable unsaturated carboxylic acid having a hydroxyl group or an epoxy ring, as in the first and second embodiments. One or more compounds (A-1) selected from the group consisting of esters and one or more compounds (A-) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group A polymer obtained by polymerizing or polymerizing and cross-linking 2) and a metal alkoxide (A-3) having a reactive functional group can also be suitably used. By using the acrylic copolymer (A) containing the metal alkoxide (A-3) having a reactive functional group, the water resistance of the coating layer 2 formed from the coating agent composition of the present invention can be improved. it can.

  Moreover, the thing similar to Embodiment 1 and 2 can be used for the isocyanate compound (B) and epoxy compound (C) concerning Embodiment 3. FIG.

  The coating agent composition concerning Embodiment 3 is 1-20 mass parts of isocyanate compounds (B) which have 2 or more isocyanate groups in 1 molecule with respect to 30 mass parts of acrylic copolymers (A), It is preferable to blend 0.1 to 5.0 parts by mass of the epoxy compound (C) having two or more epoxy rings in one molecule. More preferably, with respect to 30 parts by mass of the acrylic copolymer (A), 2 to 15 parts by mass of an isocyanate compound (B) having two or more isocyanate groups in one molecule is used. 1 to 4 parts by mass of the epoxy compound (C) having an epoxy ring is blended. This is because when the amount of the isocyanate compound (B) is less than 1 part by mass, no improvement in adhesion is recognized, and when it is more than 20 parts by mass, a decrease in weather resistance is observed. When the amount of the epoxy compound (C) is less than 0.1 parts by mass, when the coat layer 3 is formed, the desired degree of hot water resistance cannot be obtained. This is because the adhesiveness of the resin deteriorates.

  Moreover, the back surface protection sheet 20 for solar cells concerning Embodiment 3 is the base material film 1 which laminated | stacked the aluminum foil 4, and radically polymerizable unsaturated carboxylic acid which has radically polymerizable unsaturated carboxylic acid or a hydroxyl group, or an epoxy ring. One or more compounds (A-1) selected from the group consisting of esters and one or more compounds (A-) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group An emulsion or resin solution containing an acrylic copolymer (A) having 2) as a monomer unit, an isocyanate compound (B) having two or more isocyanate groups in one molecule, and the above general formula (1) An epoxy compound (C) having one or more represented repeating units and a coating agent composition mixed in a predetermined ratio are applied, Forming a coating layer 2 by by left-drying constant time removing the aqueous solvent or nonaqueous solvent.

  Or the back surface protection sheet 20 for solar cells concerning Embodiment 3 is the radically polymerizable unsaturated carboxylic acid which has a radically polymerizable unsaturated carboxylic acid, a hydroxyl group, or an epoxy ring in the base film 1 which laminated | stacked the aluminum foil 4. FIG. One or more compounds (A-1) selected from the group consisting of esters and one or more compounds (A-) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group 2) and an emulsion or resin solution containing an acrylic copolymer (A) having a metal alkoxide (A-3) having a reactive functional group as a monomer unit, and two or more isocyanate groups in one molecule Having an isocyanate compound (B) and an epoxy compound having at least one repeating unit represented by the general formula (1) (C When the by applying the coating agent composition was mixed at a predetermined ratio to form the coating layer 2 by removing the aqueous solvent or nonaqueous solvent and allowed to stand and dried for a predetermined time.

  The coating agent composition is applied to the base film 1 on which the aluminum foil 4 is laminated so that the thickness of the coating layer 2 after drying is 6 to 350 μm. As a coating method of the coating agent composition, conventionally known means such as a dipping method, a roll coating method, a screen printing method, a spray method and the like that are generally used can be used. In order to uniformly control the thickness, a plurality of thin coating layers may be laminated to have a predetermined film thickness. In the case of multiple layers, it is repeated that after the previously applied layer is dried, the next layer is applied, the layer is dried, and then the next layer is applied.

  The coating agent composition is applied to the base film 1 on which the aluminum foil 4 is laminated so that the thickness of the coating layer 2 after drying is 6 to 350 μm. As a coating method of the coating agent composition, conventionally known means such as a dipping method, a roll coating method, a screen printing method, a spray method and the like that are generally used can be used. In order to uniformly control the thickness, a plurality of thin coating layers may be laminated to have a predetermined film thickness. In the case of multiple layers, it is only necessary to repeat the application of the next layer after drying the previously applied layer, drying that layer, and then applying the next layer.

  The back surface protection sheet for solar cells according to the third embodiment is excellent in moisture heat aging resistance, adhesiveness, and water vapor barrier properties. Moreover, the back surface protection sheet for solar cells according to the third embodiment can be used for a device used in a harsh environment, for example, in an area near a coast where salt damage is likely to occur, and moisture that causes deterioration of the device. By preventing the penetration of the device, the durability of the device can be improved.

(Embodiment 4)
The back surface protection sheet for solar cells concerning Embodiment 4 of this invention is the 1st base film which consists of at least 1 layer, and the aluminum foil or 2nd base film which are arrange | positioned at least on one side of this 1st base film And an adhesive for bonding the first base film and the aluminum foil or the second base film, wherein the adhesive is a radically polymerizable unsaturated carboxylic acid. One or more compounds (A-1) selected from the group consisting of an acid, or a radically polymerizable unsaturated carboxylic acid ester having a hydroxyl group or an epoxy ring, and a radically polymerizable unsaturated carboxylic acid having no reactive functional group An acrylic copolymer (A) having one or more compounds (A-2) selected from the group consisting of esters as monomer units, and one molecule Isocyanate compound having two or more isocyanate groups (B), and at least the general formula (1)

で表される繰り返し単位を１以上有するエポキシ化合物（Ｃ）と、顔料（Ｄ）と、を混合した接着剤組成物を硬化してなることを特徴とする。

It is characterized by curing an adhesive composition in which an epoxy compound (C) having at least one repeating unit represented by the formula (C) and a pigment (D) are mixed.

  FIG. 7: is sectional drawing which shows the structure of the back surface protection sheet for solar cells which concerns on Embodiment 4 of this invention. The solar cell back surface protection sheet 30 in FIG. 7 has an aluminum foil 4 disposed on one side of the first base film 1c with an adhesive 3 interposed therebetween, and the coat layer 2 having a single layer structure is sandwiched between the aluminum foils 4. The case of the formed laminated structure is shown. The solar cell back surface protective sheet 30 according to the fourth embodiment may have a stacked structure as shown in FIGS. 8 to 11 in addition to the embodiment of FIG. 7.

  FIG. 8: is sectional drawing which shows the structure of the solar cell backsheet which concerns on the modification 1 of Embodiment 4 of this invention. The solar cell backsheet 30A of FIG. 8 arranges a second base film 1d colored via an adhesive 3 on one side of a first base film 1c having a single layer structure, and this second base film 1d. The case of the laminated structure which formed the coating layer 2 of 1 layer structure in the back surface side of the surface where the 1st base film 1c of this is arrange | positioned is shown.

  Moreover, FIG. 9 is sectional drawing which shows the structure of the solar cell backsheet which concerns on the modification 2 of Embodiment 4 of this invention. The solar cell backsheet 30B in FIG. 9 is obtained by bonding the second base film 1e having an inorganic oxide vapor deposition film functioning as a water vapor barrier layer and the first base film 1c having no inorganic oxide vapor deposition film to the adhesive 3 The case of the laminated structure which formed the coat layer 2 in the back surface side of the surface which adhere | attaches and contact | connects the 1st base film 1c of the 2nd base film 1e is shown.

  Moreover, FIG. 10 is sectional drawing which shows the structure of the solar cell backsheet which concerns on the modification 3 of Embodiment 4 of this invention. The solar battery back sheet 30C of FIG. 10 has an aluminum foil 4 disposed on one side of the first base film 1c via an adhesive 3 and is colored on the aluminum foil 4 via a transparent adhesive 3a. The case of the laminated structure which has arrange | positioned the 2nd base film 1d is shown. As long as the transparent adhesive 3a is transparent and has a desired adhesive strength, the adhesive composition of the present invention may not be added with the pigment (D) or may be another silane-based adhesive.

  FIG. 11: is sectional drawing which shows the structure of the solar cell backsheet which concerns on the modification 4 of embodiment of this invention. The solar battery back sheet 30D of FIG. 11 shows a case of a laminated structure in which a second base film 1d colored via an adhesive 3 is arranged on one side of a first base film 1c having a single layer configuration. .

  Hereinafter, each component will be described with reference to the drawings. In the following drawings, description will be made with reference to FIG. 7 as a representative, but the description contents are the same in the modified examples of FIGS.

  As the 1st base film 1c concerning Embodiment 4, the thing similar to the base film 1 of Embodiment 2 can be used.

  Moreover, as shown in FIG. 9, when laminating | stacking the 2nd base film 1e which has an inorganic oxide vapor deposition layer, it is the same material as the above-mentioned 1st base film 1c as a base film which vapor-deposits an inorganic oxide. Can be used. When bonding the 2nd base film 1e which has an inorganic oxide vapor deposition layer, it is preferable to bond a vapor deposition surface to the PET surface which does not have a vapor deposition film.

  As the inorganic oxide for vapor deposition, silicon oxide, aluminum oxide, zinc oxide, or the like can be used, and the vapor deposition thickness is preferably 1 nm to 100 nm.

  Moreover, as shown in FIGS. 8-11, when laminating the colored 2nd base film 1d, a pigment is added to the same material as the above-mentioned 1st base film 1c as the 2nd base film 1d. Then, a colored one can be used. Or what formed the vapor deposition layer of the inorganic oxide in the colored 2nd base film 1d can also be used.

(Adhesive composition)
The acrylic copolymer (A) used in the adhesive composition according to the fourth embodiment is a radical polymerizable unsaturated carboxylic acid or a group consisting of radical polymerizable unsaturated carboxylic acid esters having a hydroxyl group or an epoxy ring. One or more selected compounds (A-1) and one or more compounds (A-2) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group, As a monomer unit. One or more compounds (A-1) selected from the group consisting of radically polymerizable unsaturated carboxylic acids or radically polymerizable unsaturated carboxylic esters having a hydroxyl group or an epoxy ring, and radicals having no reactive functional group As the one or more compounds (A-2) selected from the group consisting of polymerizable unsaturated carboxylic acid esters, the same compounds as those in Embodiment 1 can be used.

  In addition, the acrylic copolymer (A) according to the fourth embodiment is a radical polymerizable unsaturated carboxylic acid or a radical polymerizable unsaturated carboxylic acid having a hydroxyl group or an epoxy ring, as in the first and second embodiments. One or more compounds (A-1) selected from the group consisting of esters and one or more compounds (A-) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no reactive functional group A polymer obtained by polymerizing or polymerizing and cross-linking 2) and a metal alkoxide (A-3) having a reactive functional group can also be suitably used. By using the acrylic copolymer (A) containing the metal alkoxide (A-3) having a reactive functional group, the water resistance of the adhesive 3 in which the adhesive composition of Embodiment 4 is effective is improved. be able to.

  Moreover, the thing similar to Embodiment 1 and 2 can be used for the isocyanate compound (B) and epoxy compound (C) concerning Embodiment 4. FIG.

  The adhesive agent composition concerning Embodiment 4 is 1-20 mass parts of isocyanate compounds (B) which have 2 or more isocyanate groups in 1 molecule with respect to 30 mass parts of acrylic copolymers (A). It is preferable that 0.1 to 15.0 parts by mass, preferably 5.0 to 15.0 parts by mass of the epoxy compound (C) having two or more epoxy rings in one molecule. More preferably, 2 to 15 parts by mass of an isocyanate compound (B) having two or more isocyanate groups in one molecule is 3 to 13 parts by mass of an epoxy compound (C) having two or more epoxy rings in one molecule. 3 to 10 parts by mass of an isocyanate compound (B) having two or more isocyanate groups in one molecule, and an epoxy compound (C) having two or more epoxy rings in one molecule It is preferable to mix 5 to 10 parts by mass. This is because when the amount of the isocyanate compound (B) is less than 1 part by mass, no improvement in adhesion is recognized, and when it is more than 20 parts by mass, a decrease in weather resistance is observed. If the compounding amount of the epoxy compound (C) is less than 3.0 parts by mass, the adhesive strength becomes insufficient, and even if it exceeds 15.0 parts by mass, the first base film 1c and the second base film 1d or 1e This is because an improvement in adhesion cannot be expected and the cost is increased. In addition, when bonding the 1st base film 1c and the aluminum foil 4, there are few compounding quantities of the epoxy compound (C) which has a 2 or more epoxy ring in 1 molecule, for example, 0.1-5. 0 parts by mass, preferably 0.5 to 4.0 parts by mass is preferably blended.

  Next, the pigment (D) used for the adhesive composition according to the fourth embodiment will be described. Color pigments and extender pigments can be used as the pigment. By adding the above-mentioned pigment to the adhesive composition, the amount of ultraviolet light that passes through the adhesive layer can be reduced, so that deterioration of the substrate can be suppressed and weather resistance can be improved. Color pigments are excellent in the effect of suppressing ultraviolet light transmission. Examples of coloring pigments include titanium oxide, cadmium red, red rice, toluidine red, yellow lead, iron yellow, titanium yellow, fast yellow, anthraquinone yellow, benzidine yellow, chromium oxide, phthalocyanine green, bitumen, ultramarine blue, phthalon cyanine blue, Examples thereof include carbon black, iron black, and graphite. Inorganic color pigments such as titanium oxide, red pepper, iron yellow, and carbon black are preferably used because of excellent weather resistance. Among these, titanium oxide is particularly preferable.

  In addition, the perylene black and iron oxide pigments disclosed in JP2011-155175A and JP2012-19138A are inferior in design properties even in a small amount. By increasing the blending amount in, it can be used without problems in appearance. The coloring pigment is preferably blended in an amount of 5 to 60 parts by weight, more preferably 10 to 50 parts by weight, particularly 20 to 40 parts by weight, based on 100 parts by weight of the acrylic copolymer (A). preferable. If the blending amount of the color pigment is small, it is difficult to obtain the effect of improving weather resistance, and if it is too large, the hot water resistance and the heat and humidity resistance decrease. Since carbon black is difficult to disperse in the adhesive composition, it is preferably used in combination with other inorganic color pigments. When carbon black and an inorganic color pigment are used in combination, 1 to 20 parts by mass, preferably 2 to 15 parts by mass of carbon black is added to 100 parts by mass of the inorganic color pigment. The inorganic coloring pigment is preferably titanium oxide. Moreover, when using an organic coloring pigment, it is preferable to use together with an inorganic coloring pigment from a viewpoint of the ultraviolet protection of a base material, and 1-100 mass of organic coloring pigments with respect to 100 mass parts of inorganic coloring pigments. By blending parts, preferably 2 to 60 parts by mass, it becomes possible to protect the substrate from ultraviolet rays for a long time.

  When carbon cracks are used as the black pigment, light reaching the solar cell back sheet 30 without being absorbed on the surface and out of the surface of the photoelectric conversion element is absorbed by the black adhesive layer and converted into heat. In the type of photothermal conversion element, for example, amorphous silicon type or compound type, when the adhesive composition of the present invention containing carbon cracks is used as an adhesive, photoelectric conversion is caused by the Stebralonsky effect accompanying the temperature rise of the element. Efficiency can be increased. On the other hand, since the adhesive composition of the present invention has very high adhesiveness, a large amount of pigment such as perylene black, which is inferior in design, can be blended in a small amount, so that the design can be performed without increasing the amount of the adhesive composition used. Can be improved. Therefore, it can be suitably used as an adhesive for a backsheet of a photothermal conversion element that does not like the temperature rise of single crystals or other crystals.

  Although extender pigments are less effective in improving weather resistance than colored pigments, extender pigments are effective in preventing blocking and reducing pinholes (small holes caused by coating agent bubbles and coating agent repellency). Examples of extender pigments include calcium carbonate, talc, kaolin clay, calcium oxide, resin beads, barium sulfate, barium carbonate, gypsum, silica, white carbon, diatomaceous earth, magnesium carbonate, aluminum hydroxide, and magnesium oxide. . The extender pigment is preferably blended in an amount of 1 to 30 parts by weight, preferably 2 to 25 parts by weight, particularly preferably 3 to 20 parts by weight, based on 100 parts by weight of the acrylic copolymer (A). When using a color pigment and an extender pigment together, it is preferable to set it as the compounding quantity of 1-60 mass parts with respect to 100 mass parts of acrylic copolymers (A) as the whole pigment. It is because hot water resistance and heat-and-moisture resistance fall when there are too many compounding quantities of a pigment.

  The acrylic copolymer (A), an isocyanate compound (B) having two or more isocyanate groups in one molecule, and an epoxy compound (C) having one or more repeating units represented by the general formula (1) ) And the pigment (D) at a predetermined ratio, the adhesive composition of Embodiment 4 can be produced.

  Moreover, the adhesive composition concerning Embodiment 4 may mix an additive as needed. Additives include surfactants such as dispersants and wetting agents, thickeners such as methylcellulose, hydroxyethylcellulose (HEC), polyacrylic acid, bentonite, antifoaming agents, film-forming aids, antifreeze agents, preservatives Examples thereof include antifungal agents and ultraviolet absorbers.

  The color pigment, extender pigment, and additive may be mixed with the isocyanate compound (B) or the epoxy compound (C) in addition to the emulsion or solution containing the acrylic copolymer (A).

  The adhesive composition is applied to the surface of the first base film 1c so that the thickness of the adhesive 3 is 3 to 30 μm. As a method for applying the adhesive composition, conventionally known means such as a dipping method, a roll coating method, a screen printing method, and a spray method which are generally used can be used. After the adhesive composition is uniformly applied on the first base film 1c by the above method, it is allowed to stand and dry for a predetermined time to remove the aqueous solvent or non-aqueous solvent, thereby removing the aluminum foil 4 and the second base film 1d. Alternatively, the first base film 1c and the aluminum foil 4, the first base film 1c and the second base film 1d or 1e are stacked by laminating 1e and press-bonding while heating to 60 ° C to 120 ° C. To do.

  When a white pigment is used as the pigment (D) of the adhesive composition according to the fourth embodiment, since the adhesive 3 serves as a reflective layer, it is necessary to further laminate a white substrate that functions as a reflective layer. There is no. Moreover, when using a black pigment as a pigment (D) of the adhesive composition of this invention, the adhesive composition excellent in the designability and adhesiveness can be provided.

  Moreover, when using a metal alkoxide (A-3) in the adhesive composition concerning Embodiment 4, by the silanol group derived from a metal alkoxide (A-3), the 1st base film 1c and the aluminum foil 4, or For improving the adhesion between the first substrate film 1c and the second substrate film 1d or 1e, and the adhesive 3 is resistant to hydrolysis even under high temperature and high humidity, and has excellent weather resistance. It can be suitably used as an adhesive composition for the backside protective sheet.

  As the aluminum foil 4 according to the fourth embodiment, the same aluminum foil 4 as that of the third embodiment can be used.

  As a coating agent composition concerning Embodiment 4, the thing similar to the coating agent composition of Embodiment 1, 2 and 3 can be used.

  The coat layer 2 according to the fourth embodiment may or may not contain the pigment (D) described above.

  The coat layer 2 of Embodiment 4 is formed on the 1st base film 1c which laminated | stacked the aluminum foil 4, or the 2nd base film 1d or 1e. The coating layer 2 includes one or more compounds (A-1) selected from the group consisting of radically polymerizable unsaturated carboxylic acids or radically polymerizable unsaturated carboxylic esters having a hydroxyl group or an epoxy ring, and reactive functional groups An emulsion or solution containing an acrylic copolymer (A) obtained by polymerizing one or more compounds (A-2) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters not having Coating agent composition in which an isocyanate compound (B) having two or more isocyanate groups in a molecule and an epoxy compound (C) having one or more repeating units represented by the general formula (1) are mixed at a predetermined ratio. It is formed by applying a product, leaving it to stand for a predetermined time, and drying to remove the aqueous solvent or non-aqueous solvent. Alternatively, the coat layer 2 is composed of one or more compounds (A-1) selected from the group consisting of radically polymerizable unsaturated carboxylic acid or radically polymerizable unsaturated carboxylic acid ester having a hydroxyl group or an epoxy ring, and reactivity. One or more compounds (A-2) selected from the group consisting of radically polymerizable unsaturated carboxylic acid esters having no functional group and a metal alkoxide (A-3) having a reactive functional group were polymerized. Emulsion or solution containing acrylic copolymer (A), isocyanate compound (B) having two or more isocyanate groups in one molecule, and one or more repeating units represented by the above general formula (1) A coating agent composition obtained by mixing the epoxy compound (C) having a predetermined ratio is applied, left to stand for a predetermined time, and dried to be an aqueous solvent or non-aqueous. It is formed by removing the solvent.

  The coating composition is applied on the first base film 1c laminated with the aluminum foil 4 or the second base film 1d or 1e so that the thickness of the coat layer 2 after drying is 6 to 350 μm. Is done. As a coating method of the coating agent composition, conventionally known means such as a dipping method, a roll coating method, a screen printing method, a spray method and the like that are generally used can be used. In order to uniformly control the thickness, a plurality of thin coating layers may be laminated to have a predetermined film thickness. In the case of multiple layers, it is repeated that after the previously applied layer is dried, the next layer is applied, the layer is dried, and then the next layer is applied.

  The back surface protective sheet for a solar cell according to Embodiment 4 is excellent in moist heat aging resistance, adhesiveness, and water vapor barrier properties, and also excellent in design properties.

  In the following examples and comparative examples, various properties were evaluated using emulsions containing two types of acrylic copolymers (ACP-1) and (ACP-2) as the acrylic copolymer (A). Went.

  The acrylic copolymer (ACP-1) is a radically polymerizable unsaturated carboxylic acid or a radically polymerizable unsaturated carboxylic acid ester (A-1) having a hydroxyl group or an epoxy ring. As radical polymerizable unsaturated carboxylic acid ester (A-2) having no functional group, 30 parts by mass of cyclohexyl methacrylate, 30 parts by mass of butyl methacrylate and 37 parts by mass of 2-ethylhexyl acrylate, metal alkoxide having a reactive functional group (A -3) is a copolymer obtained by polymerizing 1 part by mass of 3-methacryloxypropyltrimethoxysilane.

  The acrylic copolymer (ACP-2) is a radically polymerizable unsaturated carboxylic acid or a radically polymerizable unsaturated carboxylic acid ester (A-1) having a hydroxyl group or an epoxy ring. As radical polymerizable unsaturated carboxylic acid ester (A-2) having no functional group, 35 parts by mass of cyclohexyl methacrylate, 15 parts by mass of methyl methacrylate and 42 parts by mass of 2-ethylhexyl acrylate, and styrene as other polymer (A-4) It is a copolymer obtained by polymerizing 5 parts by mass.

Example 1
In Example 1, 30 parts by mass of the above acrylic copolymer (ACP-1), 15 parts by mass of titanium oxide as a coloring pigment, 9 parts by mass of talc as an extender pigment, a polyacrylic acid thickener, hydroxy The total amount of ethyl cellulose, polyether antifoaming agent, and benzotriazole ultraviolet absorber is 1 part by mass, and the balance is 45 parts by mass of solvent (total amount of solvent, water, texanol, and ethylene glycol in the emulsion and additives). The main agent (AM-1) was adjusted. Thereafter, 100 parts by mass of the adjusted main agent (AM-1), 5 parts by mass of hexamethylene diisocyanate as the isocyanate compound (B), and 3 parts by mass of the epoxy compound (C-1) as the epoxy compound (C) The thing (CC-1) was prepared. In addition, the epoxy compound (C-1) used is n = 0 in the polyglycidyl ether of the glycerin and epichlorohydrin adduct represented by the following general formula (2) and the following general formula (2). It is a mixture with glycerin and polyglycidyl ether.

A polyester film (SR55 manufactured by SKC Co., Ltd.) having a size of 10 cm × 10 cm × 0.25 cm is prepared as a substrate on which the coating agent composition (CC-1) is applied, and the coating agent is formed on the polyester film. After applying the composition so as to have an areal density of 40 g / m ² , a test piece was prepared by evaporating the solvent in the coating composition for 3 days at a temperature of 23 ° C. and a humidity of 50% and drying.

  The produced test pieces were evaluated for the coating layer adhesion, hot water resistance, moist heat resistance and gas barrier properties. Adhesion was performed according to JIS K5600-5-6: 1999 (adhesiveness (cross-cut method)), and the evaluation after the test was classified as 0 for classification 0, Δ for classification 1, and x for classification 2-5. .

The hot water resistance test was performed by immersing the test piece in hot water adjusted to 95 ° C. for 15 hours, and then removing the test piece from the hot water and visually observing the state of the coating film. For the test pieces in which no abnormality was observed by visual observation, a scratch test with a nail was performed. The evaluation criteria for the scratch test are as follows.
○: No abnormality in visual observation and scratch test △: No abnormality in visual observation, Abnormality such as peeling of coating film, wrinkle of coating film in scratching test ×: Swelling of coating film in visual observation

In the heat and humidity resistance test, the test piece was allowed to stand for 1000 hours under conditions of a temperature of 80 ° C. and a humidity of 85 RH%. Thereafter, the test piece was bent so that the bent surface was 60 ° from the horizontal plane, and then the test piece was further bent to 180 ° (the bent surface opposed to the other surface) and observed.
The evaluation criteria are as follows.
○: The base material is not cracked Δ: It is not cracked at 60 °, but it is cracked at 180 ° ×: It is cracked at 60 °

The gas barrier property was evaluated by measuring the water vapor transmission rate. Based on JIS Z0208, measurement was performed by the cup method under conditions of a temperature of 40 ° C. and a humidity of 90% RH. The tensile strength was measured using a universal testing machine (trade name “UH-500 kNI”) manufactured by Shimadzu Corporation based on JIS K7127. The evaluation criteria are as follows.
○: Water vapor transmission rate is 1 g / m ² · d or less ×: Water vapor transmission amount is 1 g / m ² · d or more Coating agent using main agent (AM-1) containing acrylic copolymer (ACP-1) The results of the composition are shown in Table 1.

(Examples 2 to 6)
Table 1 shows the main component (AM-1) containing the acrylic copolymer (ACP-1), hexamethylene diisocyanate as the isocyanate compound (B), and epoxy compound (C-1) as the epoxy compound (C). A test piece was prepared in the same manner as in Example 1 except that it was blended in About the produced test piece, the adhesiveness, hot water resistance, moist heat resistance and gas barrier properties were evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
Coating agent containing 100 parts by mass of main agent (AM-1) containing acrylic copolymer (ACP-1), 5 parts by mass of hexamethylene diisocyanate as isocyanate compound (B), and no epoxy compound (C) A composition was prepared. A test piece was produced from the prepared coating agent composition in the same manner as in Example 1, and the produced test piece was evaluated for adhesion, hot water resistance, moist heat resistance and gas barrier properties in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Examples 2 to 4)
Except that the main component (AM-1) containing the acrylic copolymer (ACP-1), the isocyanate compound (B), and the epoxy compound (C) were blended as shown in Table 1, the same manner as in Example 1 was performed. A test piece was prepared. About the produced test piece, the adhesiveness, hot water resistance, moist heat resistance and gas barrier properties were evaluated in the same manner as in Example 1. The results are shown in Table 1. The epoxy compounds (C-3) and (C-4) are epoxy compounds that do not have the repeating unit represented by the general formula (1).

(Examples 7 to 13)
Table 2 shows the main agent (AM-1) containing the acrylic copolymer (ACP-1), hexamethylene diisocyanate as the isocyanate compound (B), and epoxy compound (C-1) as the epoxy compound (C). A test piece was prepared in the same manner as in Example 1 except that it was blended in About the produced test piece, the adhesiveness, hot water resistance, moist heat resistance and gas barrier properties were evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Examples 14 to 19)
Polyglycidyl ether (C-2) of an ethylene glycol / epichlorohydrin adduct represented by the following general formula (3) is used as an epoxy compound (C), and an acrylic copolymer (ACP-1) is obtained. A test piece was produced in the same manner as in Example 1 except that the main component (AM-1), isocyanate compound (B) and epoxy compound (C-2) contained were blended as shown in Table 3. About the produced test piece, the adhesiveness, hot water resistance, moist heat resistance and gas barrier properties were evaluated in the same manner as in Example 1. The results are shown in Table 3.

(Examples 20 to 25)
Table 4 shows the main agent (AM-2) containing the acrylic copolymer (ACP-2), hexamethylene diisocyanate as the isocyanate compound (B), and epoxy compound (C-1) as the epoxy compound (C). A test piece was prepared in the same manner as in Example 1 except that it was blended in About the produced test piece, the adhesiveness, hot water resistance, moist heat resistance and gas barrier properties were evaluated in the same manner as in Example 1. The results are shown in Table 4.

(Comparative Examples 5 to 8)
Except that the main component (AM-2) containing the acrylic copolymer (ACP-2), the isocyanate compound (B), and the epoxy compound (C) were blended as shown in Table 4, the same manner as in Example 1 was performed. A test piece was prepared. About the produced test piece, the adhesiveness, hot water resistance, moist heat resistance and gas barrier properties were evaluated in the same manner as in Example 1. The results are shown in Table 4.

(Examples 26 to 32)
Except that the epoxy compound (C-1) was blended as shown in Table 5 as the main agent (AM-2) containing the acrylic copolymer (ACP-2), the isocyanate compound (B), and the epoxy compound (C). Produced a test piece in the same manner as in Example 1. About the produced test piece, the adhesiveness, hot water resistance, moist heat resistance and gas barrier properties were evaluated in the same manner as in Example 1. The results are shown in Table 5.

(Examples 33 to 38)
Polyglycidyl ether (C-2) of ethylene glycol / epichlorohydrin adduct represented by the above general formula (3) is used as the epoxy compound (C) and contains an acrylic copolymer (ACP-2) A test piece was prepared in the same manner as in Example 1 except that the main component (AM-2), isocyanate compound (B), and epoxy compound (C-2) were blended as shown in Table 6. About the produced test piece, the adhesiveness, hot water resistance, moist heat resistance and gas barrier properties were evaluated in the same manner as in Example 1. The results are shown in Table 6.

(Example 39)
In Example 39, 30 parts by mass of the above-mentioned acrylic copolymer (ACP-1), polyacrylic acid thickener, hydroxyethyl cellulose, polyether antifoaming agent, and benzotriazole ultraviolet absorber totaling 1 The main component (AM-11) was prepared by mixing 45 parts by mass of the solvent and the residue (the total amount of the solvent, water, texanol, and ethylene glycol in the emulsion and additives). Thereafter, 70 parts by mass of the prepared main agent (AM-11), 5 parts by mass of hexamethylene diisocyanate as the isocyanate compound (B), and 3 parts by mass of the epoxy compound (C-1) as the epoxy compound (C) A test piece was prepared in the same manner as in Example 1. About the produced test piece, the adhesiveness, hot water resistance, moist heat resistance and gas barrier properties were evaluated in the same manner as in Example 1. The results are shown in Table 7.

(Examples 40 to 44)
Table 7 shows the main agent (AM-11) containing the acrylic copolymer (ACP-1), hexamethylene diisocyanate as the isocyanate compound (B), and epoxy compound (C-1) as the epoxy compound (C). A test piece was prepared in the same manner as in Example 1 except that it was blended in About the produced test piece, the adhesiveness, hot water resistance, moist heat resistance and gas barrier properties were evaluated in the same manner as in Example 1. The results are shown in Table 7.

(Comparative Examples 9-12)
Except that the main component (AM-11) containing the acrylic copolymer (ACP-1), the isocyanate compound (B), and the epoxy compound (C) were blended as shown in Table 7, it was carried out in the same manner as in Example 1. A test piece was prepared. About the produced test piece, the adhesiveness, hot water resistance, moist heat resistance and gas barrier properties were evaluated in the same manner as in Example 1. The results are shown in Table 7.

(Examples 45-51)
Except that the main component (AM-11) containing the acrylic copolymer (ACP-1), the isocyanate compound (B), and the epoxy compound (C) were blended as shown in Table 8, it was carried out in the same manner as in Example 1. A test piece was prepared. About the produced test piece, the adhesiveness, hot water resistance, moist heat resistance and gas barrier properties were evaluated in the same manner as in Example 1. The results are shown in Table 8.

(Examples 52 to 57)
Polyglycidyl ether (C-2) of ethylene glycol / epichlorohydrin adduct represented by the above general formula (3) is used as the epoxy compound (C) and contains an acrylic copolymer (ACP-1) A test piece was prepared in the same manner as in Example 1 except that the main component (AM-11), isocyanate compound (B), and epoxy compound (C-2) were blended as shown in Table 9. About the produced test piece, the adhesiveness, hot water resistance, moist heat resistance and gas barrier properties were evaluated in the same manner as in Example 1. The results are shown in Table 9.

に示すような繰り返し単位を有するグリセリン・エピクロロヒドリン付加物のポリグリシジルエーテルを含有するエポキシ化合物（Ｃ−１）、およびエチレングリコール・エピクロロヒドリン付加物のポリグリシジルエーテルを配合した実施例１〜５７のコーティング剤組成物から形成されたコート層２は、ポリエステルからなる基材フィルム１に対し、良好な接着性を示すとともに、耐熱水性および耐湿熱性も非常に優れており、太陽電池用裏面保護シート１０のコート層２として使用した場合にも、高い耐水性および水蒸気バリア性を示すものと推測される。 As shown in Tables 1 to 9, the following general formula (1)

Example 1 in which an epoxy compound (C-1) containing a polyglycidyl ether of a glycerin / epichlorohydrin adduct having a repeating unit as shown in FIG. 2 and a polyglycidyl ether of an ethylene glycol / epichlorohydrin adduct was blended The coating layer 2 formed from the coating agent compositions 1 to 57 exhibits excellent adhesion to the base film 1 made of polyester, and also has excellent hot water resistance and moist heat resistance. Even when used as the coating layer 2 of the back surface protective sheet 10, it is presumed to exhibit high water resistance and water vapor barrier properties.

  On the other hand, Comparative Examples 1, 5 and 9 in which no epoxy compound was blended, and Comparative Example 3 in which an epoxy compound (C-3 and C-4) having no repeating unit represented by the general formula (1) was blended, In 4, 7, 8, 11 and 12, the adhesiveness was good, but the hot water resistance was poor. Moreover, in Comparative Examples 2, 6, and 10 containing no isocyanate compound (B), good results were not obtained in terms of adhesiveness, hot water resistance, and moist heat resistance.

(Example 58)
In Example 58, 100 parts by mass of the main agent (AM-1) containing an acrylic copolymer (ACP-1), 5 parts by mass of hexamethylene diisocyanate as the isocyanate compound (B), and an epoxy compound as the epoxy compound (C) A coating agent composition containing 0.1 part by mass of (C-1) was prepared. A 10 cm × 5 cm × 0.03 cm aluminum foil (1N30 manufactured by Sumi Light Aluminum Foil Co., Ltd.) is prepared as a base material on which the coating agent composition is applied. / M ^2, and a test piece was prepared by evaporating and drying the solvent in the coating composition at a temperature of 23 ° C. and a humidity of 50% for 3 days.

  The produced test pieces were evaluated for corrosion resistance by adhesion, hot water resistance and salt spray test. The adhesion was evaluated in accordance with JIS K5600-5-6, and the evaluation after the test was rated as 0 for classification 0, Δ for classification 1, and x for classification 2-5.

The hot water resistance test was performed by immersing the test piece in hot water adjusted to 95 ° C. for 15 hours, and then removing the test piece from the hot water and visually observing the state of the coating film. For the test pieces in which no abnormality was observed by visual observation, a scratch test with a nail was performed. The evaluation criteria for the scratch test are as follows.
○: No abnormality in visual observation and scratch test △: No abnormality in visual observation, Abnormality such as peeling of coating film, wrinkle of coating film in scratching test ×: Swelling of coating film in visual observation

Moreover, the salt spray test was conducted by conducting a salt spray test according to JIS-K5600 for 240 hours, and then taking out the test piece and visually observing the corrosion resistance of the coating film. For the test pieces in which no abnormality was observed by visual observation, a scratch test with a nail was performed. The evaluation criteria for the scratch test are as follows.
○: No abnormality in visual observation and scratch test △: No abnormality in visual observation, Abnormality such as peeling of coating film, wrinkle of coating film in scratching test ×: There is swelling in coating film by visual observation Table 10 shows the results. .

(Examples 59-63)
Table 10 shows the main agent (AM-1) containing the acrylic copolymer (ACP-1), hexamethylene diisocyanate as the isocyanate compound (B), and epoxy compound (C-1) as the epoxy compound (C). A test piece was produced in the same manner as in Example 58, except that it was blended in About the produced test piece, Al adhesiveness, hot water resistance, and corrosion resistance were evaluated in the same manner as in Example 58. The results are shown in Table 10.

(Comparative Examples 13 to 16)
Example 58 was conducted except that the main component (AM-1) containing the acrylic copolymer (ACP-1), the isocyanate compound (B), and the epoxy compound (C) were blended as shown in Table 10. A test piece was prepared. The produced test pieces were evaluated for adhesion, hot water resistance and corrosion resistance in the same manner as in Example 58. The results are shown in Table 10.

(Examples 64-69)
Table 11 shows the main agent (AM-2) containing the acrylic copolymer (ACP-2), hexamethylene diisocyanate as the isocyanate compound (B), and epoxy compound (C-1) as the epoxy compound (C). A test piece was produced in the same manner as in Example 58, except that it was blended in About the produced test piece, Al adhesiveness, hot water resistance, and corrosion resistance were evaluated in the same manner as in Example 58. The results are shown in Table 11.

(Comparative Examples 17-20)
Except that the main component (AM-2) containing the acrylic copolymer (ACP-2), the isocyanate compound (B), and the epoxy compound (C) were blended as shown in Table 11, the same manner as in Example 58 was performed. A test piece was prepared. The produced test pieces were evaluated for adhesion, hot water resistance and corrosion resistance in the same manner as in Example 58. The results are shown in Table 11.

  As shown in Table 10 and Table 11, the blending of an epoxy compound (C-1) containing a polyglycidyl ether of a glycerin / epichlorohydrin adduct having a repeating unit as shown in the above general formula (1) The coating layer 2 formed from the coating agent compositions of Examples 58 to 63 and Examples 64-69 shows good adhesion to the aluminum foil 4, and also has excellent hot water resistance and corrosion resistance. confirmed.

  In contrast, Comparative Examples 13 and 17, in which no epoxy compound was blended, and Comparative Examples 15, 16, in which an epoxy compound (C-3 and C-4) having no repeating unit represented by the general formula (1) was blended, In 19 and 20, the adhesion was good, but the hot water resistance and corrosion resistance were poor. Moreover, in Comparative Examples 14 and 18 not containing the isocyanate compound (B), good results were not obtained in terms of adhesiveness, hot water resistance, and corrosion resistance.

(Example 70)
In Example 70, 30 parts by mass of an acrylic copolymer (ACP-1), 15 parts by mass of carbon black as a coloring pigment, 9 parts by mass of talc as an extender pigment, a polyacrylic acid thickener, hydroxyethyl cellulose, Mixing so that the total amount of polyether antifoaming agent and benzotriazole UV absorber is 1 part by mass, and the balance is 45 parts by mass of solvent (total amount of solvent, water, texanol, and ethylene glycol in emulsion and additives) The main agent (AM-3) was prepared. 100 parts by mass of the main agent (AM-3) containing the prepared acrylic copolymer (ACP-1), 5 parts by mass of hexamethylene diisocyanate as the isocyanate compound (B), and an epoxy compound (C--) as the epoxy compound (C) An adhesive composition (CC-1) containing 3 parts by mass of 1) was prepared.

As shown in Table 12, a polyethylene terephthalate (PET) film (SH manufactured by SKC Co., Ltd.) having a thickness of 250 μm was used as the first base film 1c, and the adhesive composition (CC-1) was used as a comma on the PET film. after applying such a coating amount 20 g / ^{m 2,} the laminated aluminum foil 4 having a thickness of 30μm PET film.

A coating amount of a coating composition containing a white pigment on the back side of the surface of the aluminum foil 4 on which the first base film 1c is disposed on the side where the aluminum foil 4 is laminated. The coating layer 2 was formed by coating at 20 g / m ² and heating at 80 ° C. for 10 minutes to vaporize and dry the aqueous solvent.

  As the coating agent composition, a main component (AM-3) used in the adhesive composition (CC-1) in which the color pigment was changed to titanium oxide (CC-3) was used. As described above, the aluminum foil 4 having a thickness of 30 μm is laminated on one side of the first base film 1c having a thickness of 250 μm via the three layers of the black adhesive, and the coating layer 2 (ternary copolymer layer). The back surface protection sheet for solar cells laminated | stacked was obtained.

(Example 71)
As shown in Table 12, a black adhesive composition prepared in Example 70 on a polyethylene terephthalate (PET) film (SH manufactured by SKC Co., Ltd.) having a thickness of 250 μm was used as the first base film 1c. After applying the product (CC-1) to a coating amount of 20 g / m ² with a comma, a 25 μm thick second substrate film (polyethylene terephthalate (PET) film, SKC SW) is applied to the PET film. Laminated.

A coating agent composition comprising a white pigment on the back side of the surface of the first base film 1c on which the first base film 1c is disposed, on the side where the second base film is laminated. CC-3) was applied with a comma to a coating amount of 20 g / m ² and heated at 80 ° C. for 10 minutes to vaporize and dry the aqueous solvent to form a coating layer 2. The same coating agent composition (CC-3) as in Example 70 was used.
As described above, the second base film having a thickness of 25 μm is laminated on one side surface of the first base film 1c having a thickness of 250 μm via the three layers of black adhesive, and the coating layer 2 (ternary copolymer) The back surface protection sheet for solar cells laminated | stacked was obtained.

(Example 72)
As shown in Table 12, a polyethylene terephthalate (PET) film (SH manufactured by SKC Co., Ltd.) having a thickness of 250 μm was used as the first base film 1c, and the black adhesive composition (CC-1) was placed on the PET film. After applying so as to have an application amount of 20 g / m ² with a comma, an aluminum foil 4 having a thickness of 30 μm was laminated on the PET film.

A coating amount of 20 g / m ² of a transparent adhesive on the side of the first base film 1c on which the aluminum foil 4 is laminated, on the back side of the surface of the aluminum foil 4 on which the first base film 1c is disposed. Then, a white second base film 1d (polyethylene terephthalate (PET) film, SW manufactured by SKC Corporation) having a thickness of 38 μm was further laminated. The transparent adhesive used for adhesion | attachment with the aluminum foil 4 and the 2nd base film 1d used what remove | excluded the color pigment from adhesive composition (CC-1).
As described above, the aluminum foil 4 having a thickness of 30 μm is laminated on one side of the first base film 1c having a thickness of 250 μm via the three layers of black adhesive, and further, a white second film having a thickness of 38 μm is formed by the transparent adhesive. The back surface protection sheet for solar cells on which the base film 1d was further laminated was obtained.

(Example 73)
As shown in Table 12, a polyethylene terephthalate (PET) film (SH manufactured by SKC Co., Ltd.) having a thickness of 250 μm was used as the first base film 1c, and the black adhesive composition (CC-1) was placed on the PET film. After applying so as to have an application amount of 20 g / m ² with a comma, a white second base film 1d (polyethylene terephthalate (PET) film, SW manufactured by SKC Corporation) having a thickness of 38 μm was laminated on the PET film.

  As described above, a solar cell back surface protective sheet in which a 38 μm-thick second base film 1 d was laminated on one side of the 250 μm-thick first base film 1 c via three black adhesive layers was obtained. .

(Example 74)
As shown in Table 12, using the polyethylene terephthalate (PET) film (SH manufactured by SKC Co., Ltd.) having a thickness of 250 μm as the first base film 1c, the black adhesive composition of Example 1 (CC -1) The pigment of the first base film 1c having a thickness of 250 μm was obtained in the same manner as in Example 70, except that the pigment of perylene black (Paliogen Black S0081, manufactured by BASF Corporation) was changed (20 parts by mass). A back protective sheet for solar cells in which an aluminum foil 4 having a thickness of 30 μm is laminated on one side with three layers of black (perylene black) adhesive, and further, a coat layer 2 (ternary copolymer layer) is further laminated. Got.

(Example 75)
In Example 75, 30 parts by mass of an acrylic copolymer (ACP-2), 15 parts by mass of carbon black as a coloring pigment, 9 parts by mass of talc as an extender pigment, a polyacrylic acid thickener, hydroxyethyl cellulose, Mixing so that the total amount of polyether antifoaming agent and benzotriazole UV absorber is 1 part by mass, and the balance is 45 parts by mass of solvent (total amount of solvent, water, texanol, and ethylene glycol in emulsion and additives) The main agent (AM-4) was prepared. 100 parts by mass of main agent (AM-4) containing adjusted acrylic copolymer (ACP-1), 5 parts by mass of hexamethylene diisocyanate as isocyanate compound (B), and epoxy compound (C--) as epoxy compound (C) An adhesive composition (CC-2) containing 3 parts by mass of 1) was prepared.

As shown in Table 13, a polyethylene terephthalate (PET) film (SH manufactured by SKC Co., Ltd.) having a thickness of 250 μm was used as the first substrate film 1c, and an adhesive composition (CC-2) was used on the PET film as a comma. after applying such a coating amount 20 g / ^{m 2,} the laminated aluminum foil 4 having a thickness of 30μm PET film.

A coating amount of a coating composition containing a white pigment on the back side of the surface of the aluminum foil 4 on which the first base film 1c is disposed on the side where the aluminum foil 4 is laminated. The coating layer 2 was formed by coating at 20 g / m ² and heating at 80 ° C. for 10 minutes to vaporize and dry the aqueous solvent.

  As the coating agent composition, a main component (AM-4) used in the adhesive composition (CC-2) in which the color pigment was changed to titanium oxide (CC-4) was used. As described above, the aluminum foil 4 having a thickness of 30 μm is laminated on one side of the first base film 1c having a thickness of 250 μm via the three layers of the black adhesive, and the coating layer 2 (ternary copolymer layer). The back surface protection sheet for solar cells laminated | stacked was obtained.

(Example 76)
In Example 76, as shown in Table 13, the adhesive composition (CC-2) used in Example 75 was used as the black adhesive composition, and the coating composition ( A second substrate having a thickness of 25 μm is provided on one side of the first substrate film 1c having a thickness of 250 μm via three black adhesive layers in the same manner as in Example 71 except that CC-4) is used. A back protective sheet for a solar cell in which a film was laminated and a coat layer 2 (ternary copolymer layer) was further laminated was obtained.

(Example 77)
In Example 77, as shown in Table 13, the thickness was the same as in Example 72 except that the adhesive composition (CC-2) used in Example 75 was used as the black adhesive composition. 30 μm thick on one side of 250 μm first base film 1 c with three layers of black adhesive on one side of 250 μm thick first base film 1 c with three layers of black adhesive The back surface protection sheet for solar cells by which the aluminum foil 4 of this was further laminated | stacked, and also the white 2nd base film 1d of 38 micrometers thickness was further laminated | stacked with the transparent adhesive agent was obtained.

(Example 78)
In Example 78, as shown in Table 13, the thickness was the same as in Example 73 except that the adhesive composition (CC-2) used in Example 75 was used as the black adhesive composition. A back protective sheet for a solar cell was obtained in which a 38 μm-thick second substrate film 1 d was laminated on one side of a 250 μm first substrate film 1 c with three layers of black adhesive.

(Example 79)
In Example 79, as shown in Table 13, the adhesive composition (CC-2) used in Example 75 was used as the black adhesive composition, and the pigment was Perylene Black (perylene manufactured by BASF Corporation). Black Paliogen Black S0081) (20 parts by mass). Further, black (perylene black) was formed on one side of the first base film 1c having a thickness of 250 μm in the same manner as in Example 74 except that the coating composition (CC-4) was used as the white coating composition. ), An aluminum foil 4 having a thickness of 30 μm was laminated, and further a back protective sheet for solar cells was obtained, in which a coat layer 2 (ternary copolymer layer) was laminated.

(Comparative Example 21)
As shown in Table 14, a black polyethylene terephthalate (PET) film (SB manufactured by SKC Co., Ltd.) having a thickness of 250 μm was used as the first base film 1c, and a transparent adhesive (Toyo Ink Manufacturing SC Holding Co., Ltd.) was used on this PET film. LIS-809: CR-001: Ethyl acetate = 100: 10: 32.5 parts by mass) was applied with a comma, the solvent was dried, and an adhesive layer having an application amount of 20 g / m ² was formed. An aluminum foil 4 having a thickness of 30 μm was laminated on the PET film.

A transparent adhesive (LIS-, manufactured by SC Holding Co., Ltd.) on the side of the first base film 1c on which the aluminum foil 4 is laminated and on the back side of the surface on which the first base film 1c of the aluminum foil 4 is disposed. 809: CR-001: ethyl acetate = 100: 10: 32.5 parts by mass) was applied at a coating amount of 20 g / m ² with a comma, and the solvent was dried to provide an adhesive layer. A second substrate film 1d having a thickness of 38 μm (polyethylene terephthalate (PET) film, SKC SW) was further laminated.
As described above, the aluminum foil 4 having a thickness of 30 μm is laminated on one side surface of the first base film 1c having a thickness of 250 μm via the transparent adhesive, and the white second base film having a thickness of 38 μm is further formed by the transparent adhesive. A back protective sheet for a solar cell in which 1d was further laminated was obtained.

(Comparative Example 22)
As shown in Table 14, a polyethylene terephthalate (PET) film (SH manufactured by SKC Co., Ltd.) having a thickness of 188 μm was used as the first base film 1c, and the same formulation and the same thickness as Comparative Example 21 were formed on this PET film. A transparent adhesive layer was formed, and a white second substrate film 1d (polyethylene terephthalate (PET) film, SW manufactured by SKC Corporation) having a thickness of 38 μm was laminated on the PET film.

A transparent adhesive layer having the same formulation and the same thickness as that of Comparative Example 21 is formed on the back surface of the first substrate film 1c on the side where the second substrate film 1d is laminated, and the second substrate having a black thickness of 38 μm is formed. A base film 1d (polyethylene terephthalate (PET) film, SB manufactured by SKC Corporation) was further laminated.
As described above, the white second base film 1d having a thickness of 38 μm is laminated on one side surface of the first base film 1c having a thickness of 188 μm via the transparent adhesive, and transparent adhesive is further applied to the opposite side surface. The back surface protection sheet for solar cells on which the 38-micrometer-thick black 2nd base film 1d was further laminated | stacked by the agent was obtained.

(Comparative Example 23)
As shown in Table 14, a polyethylene terephthalate (PET) film (SH manufactured by SKC Co., Ltd.) having a thickness of 250 μm is used as the first base film 1c, and is disclosed in JP 2011-155175 A on this PET film. A black adhesive containing black pigment perylene black (perylene black palogen black S0084 manufactured by BASF Corp.) was applied with a comma, the solvent was dried, and an adhesive layer having an application amount of 20 g / m ² was provided. A 25 μm transparent second substrate film (polyethylene terephthalate (PET) film, SKC SH) was laminated on the PET film.

The same white pigment as in Example 70 on the side of the first base film 1c on which the second base film is laminated, on the back side of the surface of the second base film on which the first base film 1c is disposed. The coating agent composition containing CC (CC-3) was applied with a comma to a coating amount of 20 g / m ² and heated at 80 ° C. for 10 minutes to vaporize and dry the aqueous solvent to form the coating layer 2.
As described above, the second base film having a thickness of 25 μm is laminated on one side surface of the first base film 1 c having a thickness of 250 μm via the black adhesive, and the coat layer 2 (ternary copolymer) is further formed. The back surface protection sheet for solar cells laminated | stacked was obtained.

  The black adhesive was prepared by mixing a polyester resin solution, a black pigment, a curing agent solution, an epoxy resin solution, and dibutyltin urarate at a mass ratio of 85: 10: 15: 15: 0.25.

  In addition, said polyester resin solution was prepared as follows. The reaction vessel was charged with 99.6 parts by weight of dimethyl terephthalate, 92.2 parts by weight of ethylene glycol, 72.2 parts by weight of neopentyl glycol, and 0.02 parts by weight of zinc acetate. The mixture was heated to 0 ° C. to conduct a transesterification reaction. After 97% of the theoretical amount of methanol was distilled, 77.5 parts by mass of isophthalic acid and 166.9 parts by mass of azelaic acid were charged and heated to 160 to 240 ° C. to carry out the reaction under ester. The reactor was gradually reduced in pressure to 1-2 torr, the number average molecular weight was 41,000, the hydroxyl value was 3.2 (mgKOH / g), the acid value was 0.7 (mgKOH / g), and the Tg was −10 ° C. Polyester polyol was obtained and diluted with ethyl acetate to obtain a polyester resin solution (A) having a solid content of 50%. Separately, polyester resin “Byron 200” (Toyobo Co., Ltd., number average molecular weight 17000, hydroxyl value 6 (mgKOH / g), acid value 2 (mgKOH / g), Tg 67 ° C. dissolved in methyl ethyl ketone and solid A polyester resin solution (B) having a content of 50% was obtained, and then the polyester resin solutions (A) and (B) were mixed at a mass ratio of 1: 1 to obtain a polyester resin solution having a solid content of 50%. The polyester resin in this polyester resin solution had a hydroxyl value of 4.6 (mg KOH / g), an acid value of 0.8 (mg KOH / g), and a Tg of 28 ° C.

  The above curing agent solution is prepared by mixing a trimer of isophorone diisocyanate blocked with MEK oxime and a trimer of hexamethylene diisocyanate blocked with MEK oxime at a mass ratio of 1: 1. A resin solution having a solid content of 50% diluted with ethyl was used as a curing agent solution. In addition, the epoxy resin solution is a resin solution having a solid content of 50% by diluting a solid solution of 79 to 81% containing 450 to 500 gram equivalent of an epoxy group dissolved in MEK with ethyl acetate. used.

(Comparative Example 24)
As shown in Table 14, a polyethylene terephthalate (PET) film (SH manufactured by SKC Co., Ltd.) having a thickness of 250 μm was used as the first base film 1c, and the same prescription and the same thickness as Comparative Example 23 were formed on this PET film. The aluminum foil 4 having a thickness of 30 μm was laminated on the PET film.

A coating agent containing the same white pigment as in Example 70 on the side of the first base film 1c on which the aluminum foil 4 is laminated and on the back side of the surface on which the first base film 1c of the aluminum foil 4 is disposed. The composition (CC-3) was applied with a comma to a coating amount of 20 g / m ² , heated at 80 ° C. for 10 minutes to vaporize and dry the aqueous solvent, thereby forming the coat layer 2.
As described above, the aluminum foil 4 having a thickness of 30 μm is laminated on one side surface of the first base film 1c having a thickness of 250 μm via the black adhesive, and further the coat layer 2 (ternary copolymer layer). The back surface protection sheet for solar cells laminated | stacked was obtained.

  The appearance of each of the back protective sheets for solar cells of Examples 70 to 79 and Comparative Examples 21 to 24 and the durability of the adhesive were evaluated. Table 12 shows the results (Examples 70 to 74) of the adhesive composition (CC-1) using the main agent (AM-3) containing the acrylic copolymer (ACP-1). Table 13 shows the results (Examples 75 to 79) of the adhesive composition (CC-2) using the main agent (AM-4) containing ACP-2), and Table 14 shows Comparative Examples 21 to 24.

  Appearance was evaluated for the produced solar cell back surface protective sheet by ○, Δ, ×, and the durability of the adhesive was evaluated by a hot water immersion test for each of the above solar cell back surface protective sheets at 90 ° C for 96 hours. (O: no peeling, x: floating or peeling).

  It was confirmed that the back surface protection sheets for solar cells of Examples 70 to 79 were excellent in appearance and durability of the adhesive layer.

  As described above, according to the present invention, it is possible to provide a back surface protection sheet for a solar cell including a coating layer having excellent adhesion, water resistance, and water vapor barrier properties on the outer side of the base film, and the solar cell in a harsh environment. It can be used as a back sheet. In addition, the coating composition of the present invention can form a coating film having excellent adhesion, water resistance and vapor barrier properties, and includes a protective sheet, an electronic circuit board, a bathroom (unit bath), a kitchen, a bathroom, Plastic articles, equipment and devices used around water such as toilets, and parts thereof, plastic articles, equipment and equipment used outdoors such as garage roofing materials, and parts thereof, portable It can be used as a coating composition for base materials used in harsh environments such as telephones, water tanks, light-shielding films, and artificial marble.

DESCRIPTION OF SYMBOLS 1 Base film 1a, 1c 1st base film 1b, 1d, 1e 2nd base film 2 Coat layer 3 Adhesive 4 Aluminum foil 10, 10A, 10B, 20, 20A, 20B, 30, 30A, 30B, 30C , 30D Back protection sheet for solar cell

Claims (20)

One or more compounds (A-1) selected from the group consisting of radically polymerizable unsaturated carboxylic acids or radically polymerizable unsaturated carboxylic esters having a hydroxyl group or an epoxy ring, and radical polymerization having no reactive functional group An acrylic copolymer (A) having at least one compound (A-2) selected from the group consisting of a polymerizable unsaturated carboxylic acid ester as a monomer unit;
An isocyanate compound (B) having two or more isocyanate groups in one molecule;
At least general formula (1)

And an epoxy compound (C) having at least one repeating unit represented by the formula:   The isocyanate compound (B) is contained in an amount of 1 to 20 parts by mass and the epoxy compound (C) is contained in an amount of 0.1 to 15 parts by mass with respect to 30 parts by mass of the acrylic copolymer (A). The coating agent composition described in 1.   The said epoxy compound (C) is the epichlorohydrin addition product of a polyhydric alcohol, The coating agent composition of Claim 1 or 2 characterized by the above-mentioned.   The epoxy compound (C) has an epichlorohydrin adduct of a polyhydric alcohol having a repeating unit represented by the general formula (1) and a repeating unit represented by the general formula (1). The coating agent composition according to claim 3, which is a mixture with an epichlorohydrin adduct of a polyhydric alcohol that is not used. A back protective sheet for solar cells, comprising a base film composed of at least one layer and a coat layer composed of at least one layer formed on at least one side of the base film,
The said coating layer hardens the coating agent composition as described in any one of Claims 1-4, The back surface protection sheet for solar cells characterized by the above-mentioned.   The said base film consists of polyester-type resin, The back surface protection sheet for solar cells of Claim 5 characterized by the above-mentioned. It consists of a base film composed of at least one layer, an aluminum foil disposed on one side or both sides of the base film, and at least one layer disposed on the opposite side of the surface of the aluminum foil in contact with the base film. A back protective sheet for a solar cell having one or more coat layers,
The coat layer is
One or more compounds (A-1) selected from the group consisting of radically polymerizable unsaturated carboxylic acids or radically polymerizable unsaturated carboxylic esters having a hydroxyl group or an epoxy ring, and radical polymerization having no reactive functional group An acrylic copolymer (A) having at least one compound (A-2) selected from the group consisting of a polymerizable unsaturated carboxylic acid ester as a monomer unit;
An isocyanate compound (B) having two or more isocyanate groups in one molecule;
At least general formula (1)

An epoxy compound (C) having one or more repeating units represented by:
A back surface protective sheet for solar cells, which is obtained by curing a coating agent composition containing   The coating layer comprises 1 to 20 parts by mass of the isocyanate compound (B) and 0.1 to 5.0 parts by mass of the epoxy compound (C) with respect to 30 parts by mass of the acrylic copolymer (A). It formed from the coating agent composition containing, The back surface protection sheet for solar cells of Claim 7 characterized by the above-mentioned.   The said epoxy compound (C) is an epichlorohydrin addition product of a polyhydric alcohol, The back surface protection sheet for solar cells of Claim 7 or 8 characterized by the above-mentioned.   The epoxy compound (C) has an epichlorohydrin adduct of a polyhydric alcohol having a repeating unit represented by the general formula (1) and a repeating unit represented by the general formula (1). The back protective sheet for solar cells according to claim 9, which is a mixture with an epichlorohydrin adduct of a polyhydric alcohol that is not used.   The back coating sheet for a solar cell according to any one of claims 7 to 10, wherein the coating layer contains a pigment.   The thickness of the said aluminum foil is 9-30 micrometers, The back surface protection sheet for solar cells as described in any one of Claims 7-11 characterized by the above-mentioned. A first base film composed of at least one layer; an aluminum foil or a second base film disposed on at least one side of the first base film; the first base film and the aluminum foil or the second base An adhesive for adhering a material film, and a back surface protection sheet for solar cells,
The adhesive is
One or more compounds (A-1) selected from the group consisting of radically polymerizable unsaturated carboxylic acids or radically polymerizable unsaturated carboxylic esters having a hydroxyl group or an epoxy ring, and radical polymerization having no reactive functional group An acrylic copolymer (A) having at least one compound (A-2) selected from the group consisting of a polymerizable unsaturated carboxylic acid ester as a monomer unit;
An isocyanate compound (B) having two or more isocyanate groups in one molecule;
At least general formula (1)

An epoxy compound (C) having one or more repeating units represented by:
The back surface protection sheet for solar cells formed by hardening | curing the adhesive composition which mixes.   When bonding the first base film and the aluminum foil, the adhesive is 1 to 20 parts by mass of the isocyanate compound (B) with respect to 30 parts by mass of the acrylic copolymer (A), and the epoxy. The back surface protection sheet for solar cells according to claim 13, comprising 0.1 to 5.0 parts by mass of the compound (C).   The back protective sheet for solar cell according to claim 13, wherein the second base film is a base film having an inorganic oxide vapor deposition layer or a colored base film.   When adhering the first base film and the second base film, the adhesive is 1 to 20 masses of the isocyanate compound (B) with respect to 30 mass parts of the acrylic copolymer (A). The back surface protection sheet for solar cells according to claim 15, comprising 0.1 to 15.0 parts by mass of the epoxy compound (C).   The said epoxy compound (C) is an epichlorohydrin addition product of a polyhydric alcohol, The back surface protection sheet for solar cells as described in any one of Claims 13-16 characterized by the above-mentioned.   The epoxy compound (C) has an epichlorohydrin adduct of a polyhydric alcohol having a repeating unit represented by the general formula (1) and a repeating unit represented by the general formula (1). The back protective sheet for solar cells according to claim 17, which is a mixture with an epichlorohydrin adduct of a polyhydric alcohol that does not.   The said adhesive agent contains a pigment (D), The back surface protection sheet for solar cells as described in any one of Claims 13-18 characterized by the above-mentioned. The solar cell protective sheet includes a first base film composed of at least one layer, an aluminum foil disposed on at least one side of the first base film, and a surface on which the first base of the aluminum foil is disposed. And a second base material disposed on the back surface of the first base film, the first base film and the aluminum foil, and an adhesive for bonding the aluminum foil and the second base film. Item 20. The back protective sheet for solar cells according to any one of Items 14 to 19.

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