JP2017179051A - Anchor coating agent for solar cell, protective material, and solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anchor coating agent for a solar cell, which has good storage stability and excellent characteristics with time such as peeling strength and weather resistance, a protective material, and a solar cell module.SOLUTION: The anchor coating agent for a solar cell comprises a resin, a curing agent, spherical particles having an average particle diameter of 1 to 30 μm, and an antioxidant. The agent preferably contains the antioxidant by 0.1 to 20 parts by mass with respect to 100 parts by mass of the resin. The agent preferably contains the spherical particles by 0.1 to 20 parts by mass with respect to 100 parts by mass of the resin.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an anchor coating agent used on a surface where a sealing material of a solar cell and a protective material are in contact.

  2. Description of the Related Art In recent years, solar cells (solar power generation) that have attracted attention as clean energy are generally configured as solar cell modules in which a sealing material and a protective material are sequentially stacked on both sides of a solar cell element. Typical examples of the protective material include a glass plate and a resin protective material (hereinafter also referred to as “protective material”). A glass plate is very excellent in transparency, weather resistance, and scratch resistance, but has problems in cost, safety, and workability. On the other hand, since the protective material is excellent in terms of cost, safety, and workability, various types of protective materials have been proposed (for example, Patent Document 1). As the sealing material, an ethylene-vinyl acetate copolymer (hereinafter referred to as “EVA”), which is highly transparent and excellent in moisture resistance, is usually used.

The protective material is required to have various performances, and among them, a high degree of close contact with the sealing material is required, and thus the peel strength from the sealing material is important. If the peel strength from the sealing material is insufficient, the protective material is peeled off, and the solar cell element cannot be protected from moisture or external factors, so that the output of the solar cell is deteriorated.
As a method of ensuring the peel strength with the sealing material, (1) a method of applying an anchor coating agent to the surface of the protective material in contact with the sealing material, or (2) a surface of the protective material in contact with the sealing material. Although the method of using a film with high peeling strength with a stopping material is mentioned, the method of said (1) is performed in recent years from a viewpoint of cost or efficiency.
Various types of anchor coating agents are known. For example, Patent Document 2 discloses an anchor coating agent containing a vinyl polymer having an ethylenically unsaturated double bond at the end of a side chain. .

Japanese Patent Laid-Open No. 2004-200322 JP 2013-071948 A

  However, with conventional anchor coating agents, when solar cells are used for a long period of time, the adhesion with the substrate decreases, the anchor coat layer turns yellow, and the thickness decreases due to decomposition of the anchor coat layer. There was a problem.

  An object of this invention is to provide the anchor coating agent for solar cells, a protective material, and a solar cell module which are excellent in temporal characteristics, such as peeling strength and a weather resistance.

  The anchor coating agent for solar cells of the present invention includes a resin, a curing agent, an antioxidant, and spherical particles having an average particle diameter of 1 to 30 μm.

  According to the present invention, the anchor coating agent contains spherical particles having an average particle diameter of 1 to 30 μm, and an antioxidant in addition to the resin and the curing agent, thereby improving the weather resistance in addition to improving the peel strength. was gotten.

  According to the present invention, it is possible to provide a solar cell anchor coating agent, a protective material, and a solar cell module, which are excellent in aging characteristics such as peel strength and weather resistance.

Sectional drawing of the module for solar cells.

  Terms used in this specification will be explained. “Film” and “sheet” are synonymous. The “(meth) acrylic resin” includes “acrylic resin”, “methacrylic resin”, and “acrylic-methacrylic resin”. “(Meth) acryloyl” includes “acryloyl” and “methacryloyl”. “(Meth) acryl” includes “acryl” and “methacryl”. An adherend refers to a counterpart to which a base material on which an anchor coat layer is formed is bonded.

  The anchor coating agent of the present invention contains a resin, a curing agent, spherical particles having an average particle diameter of 1 to 30 μm, and an antioxidant. The anchor coating agent is preferably used as a coating sheet by coating on a substrate to form an anchor coating layer. A high peel strength can be obtained by bonding the coated sheet to an adherend. The adherend is preferably various plastic materials, and is preferably EVA or a polyolefin film used for a solar cell encapsulant.

  Thus, it is preferable to use the anchor coating agent of this invention as an anchor coating agent for solar cells. Moreover, it is preferable to use the said coating sheet as a protective material which is one of the members which comprise a solar cell module. Hereinafter, it demonstrates centering on the embodiment of the anchor coating agent for solar cells, and a protective material.

  Since the anchor coating agent of the present invention contains spherical particles, the particles reflect or scatter the light, thereby making it easier to shield ultraviolet rays, thereby improving the weather resistance. Further, by including the resin and the spherical particles, the spherical particles are scattered on the surface of the anchor coat layer, and unevenness is generated. This increases the contact area with the anchor coat layer during thermocompression bonding with the sealing material, thereby further improving the peel strength from the adherend.

  The resin is preferably, for example, a (meth) acrylic resin, polyester, polyurethane, polyolefin or the like.

In the present invention, the (meth) acrylic resin is obtained by making the (meth) acrylic monomer essential and copolymerizing other vinyl monomers as necessary.
Examples of (meth) acrylic monomers include (meth) acrylic acid alkyl esters, hydroxyl group-containing monomers, carboxyl group-containing monomers, glycidyl group-containing monomers, and other vinyl monomers. The monomer is an ethylenically unsaturated double bond-containing monomer.

  Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, normal butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate and the like.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like.

  Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, citraconic acid and the like.

  Examples of the glycidyl group-containing monomer include glycidyl acrylate, glycidyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether, and the like.

  Examples of other vinyl monomers include monomers copolymerizable with (meth) acrylic monomers such as vinyl acetate, maleic anhydride, vinyl ether, vinyl propionate, and styrene.

  As a method for synthesizing the (meth) acrylic resin, a known polymerization method such as normal radical polymerization, for example, solution polymerization, bulk polymerization, and emulsion polymerization can be used. Among these methods, solution polymerization is preferable. The polymerization initiator used for the polymerization reaction is preferably a peroxide or an azo compound. Examples of the peroxide include benzoyl peroxide, acetyl peroxide, methyl ethyl ketone peroxide, lauroyl peroxide, and the like. Examples of the azo compound include azobisisobutyronitrile.

Polyester can be synthesized by reacting a carboxylic acid component and a hydroxyl component in accordance with a conventional method (esterification reaction or transesterification reaction).
Examples of the carboxylic acid component include benzoic acid, p-tert-butylbenzoic acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic anhydride, adipic acid, azelaic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride Examples include acid, fumaric acid, itaconic acid, tetrachlorophthalic anhydride, 1,4-cyclohexanedicarboxylic acid, trimellitic anhydride, methylcyclohexericarboxylic anhydride, pyromellitic anhydride, ε-caprolactone, and fatty acid.

  Examples of the hydroxyl component include ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, triethylene glycol, 3-methylpentanediol, 1,4- In addition to diol components such as cyclohexanedimethanol, polyfunctional alcohols such as glycerin, trimethylolethane, trimethylolpropane, trishydroxymethylaminomethane, pentaerythritol, and dipentaerythritol can be mentioned.

  Polyurethane can be synthesized by reacting an isocyanate compound and a hydroxyl component according to a conventional method.

  Examples of the isocyanate compound include trimethylene diisocyanate (TDI), hexamethylene diisocyanate (HDI), methylenebis (4,1-phenylene) = diisocyanate (MDI), 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI). ), Diisocyanates such as xylylene diisocyanate (XDI), trimethylolpropane adducts of these diisocyanates, isocyanurates that are trimers of these diisocyanates, and burette conjugates of these diisocyanates, polymeric diisocyanates, etc. .

  Examples of the hydroxyl component include polyester polyol, polyether polyol, polycarbonate polyol, and polyurethane polyol which is a reaction product of these polyol and diisocyanate.

  Examples of the polyester polyol include a polyester polyol having a hydroxyl group at the molecular end in the polyester described above.

  Polyether polyol is obtained by polymerizing an oxirane compound such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran using a compound having two or more hydroxyl groups such as ethylene glycol or propylene glycol, or water as an initiator. Examples include synthesized polyether polyols. Specific examples include compounds having 2 or more functional groups such as polypropylene glycol, polyethylene glycol, and polytetramethylene glycol.

  The polycarbonate polyol includes, for example, (1) a reaction product of a compound having two or more hydroxyl groups such as ethylene glycol and propylene glycol and a carbonate ester, and (2) two or more hydroxyl groups such as ethylene glycol and propylene glycol. And compounds obtained by reacting phosgene with a compound having a phosgene in the presence of an alkali.

  Examples of the carbonic acid ester used in the production method (1) include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, and propylene carbonate.

  Known catalysts can be used in synthesizing the polyurethane. Examples of the catalyst include tertiary amine compounds and organometallic compounds.

  Examples of the tertiary amine compound include triethylamine, triethylenediamine, N, N-dimethylbenzylamine, N-methylmorpholine, 1,8-diazabicyclo- (5,4,0) -undecene-7 (DBU), and the like. It is done.

Examples of the organometallic compound include a tin compound and a non-tin compound.
Examples of tin compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, tributyltin acetate. , Triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, tin 2-ethylhexanoate and the like.

  Non-tin compounds include, for example, titanium-based compounds such as dibutyltitanium dichloride, tetrabutyltitanate, butoxytitanium trichloride, lead-based compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, lead naphthenate, 2-ethyl Examples thereof include iron systems such as iron hexanoate and iron acetylacetonate, cobalt systems such as cobalt benzoate and cobalt 2-ethylhexanoate, zinc systems such as zinc naphthenate and zinc 2-ethylhexanoate, and zirconium naphthenate. .

  Polyolefin can be synthesized by a known method of radical polymerization of an ethylenic monomer. The polyolefin may be a homopolymer or a copolymer (copolymer), and is preferably a copolymer (copolymer).

  Examples of the ethylenic monomer include olefins such as ethylene, propylene, n-butene, isobutylene, 2-butene, cyclopentene, and cyclohexene; methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, n-hexyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl Vinyl ethers such as vinyl ether, hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether; vinyl esters such as vinyl acetate, vinyl caproate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl benzoate, vinyl cyclohexylcarboxylate, etc. Can be mentioned. The ethylenic monomer can be used alone or in combination of two or more.

  Examples of commercially available polyolefins include “Unistall” (manufactured by Mitsui Chemicals), “Auroren” (manufactured by Nippon Paper Chemicals), and the like.

  The resin used in the present invention can have an ethylenically unsaturated double bond. Peel strength of adherend (for example, solar cell sealing material is EVA sheet) subjected to radical crosslinking polymerization when the resin has an ethylenically unsaturated double bond and heat-pressing the protective material and the adherend Will be improved. In particular, when the sealing material is not eva but EVA, it usually does not contain peroxide or the like. In this case, the resin does not necessarily have to have an ethylenically unsaturated double bond.

  Resins having an ethylenically unsaturated double bond can be obtained by, for example, adding a functional group capable of reacting with a hydroxyl group to the resin by a known method, and reacting the functional group with a hydroxyl group having an ethylenically unsaturated double bond. Can be synthesized. In the present invention, since it is important to use a resin regardless of the synthesis route, it goes without saying that the present invention is not limited to the following synthesis method.

  The functional group capable of reacting with the hydroxyl group is preferably an isocyanate group, for example.

  Examples of the method of introducing an isocyanate group into the (meth) acrylic resin include a method of using a (meth) acrylic monomer having an isocyanate group as the (meth) acrylic monomer. Examples of the (meth) acrylic monomer having an isocyanate group include 2-isocyanatoethyl acrylate and 2-isocyanatoethyl methacrylate. Commercial products of the (meth) acrylic monomer having an isocyanate group include Karenz AOI and Karenz MOI manufactured by Showa Denko KK.

  As a method for introducing an isocyanate group into the polyester, for example, when a polyester is obtained by reacting a carboxylic acid component and a hydroxyl component, a hydroxyl group component is excessive to obtain a polyester having a terminal hydroxyl group, The method of adding diisocyanate is mentioned.

  As a method for introducing an isocyanate group into polyurethane, for example, when a polyurethane is obtained by reacting an isocyanate compound with a hydroxyl component, a polyurethane having a terminal isocyanate group can be obtained by increasing the amount of the isocyanate compound.

  In the present invention, the mass average molecular weight of the resin is preferably 10,000 to 1,000,000, more preferably 20,000 to 750,000, and still more preferably 30,000 to 500,000. When the mass average molecular weight of the resin is 1,000,000 or less, the coatability of the anchor coating agent is further improved. Moreover, when the mass average molecular weight is 10,000 or more, the peel strength after the moist heat resistance test of the anchor coating agent is further improved.

  In addition, a mass average molecular weight is the value of polystyrene conversion by gel permeation chromatography (GPC) of resin. For example, the temperature of the columns (KF-805L, KF-803L, and KF-802 manufactured by Showa Denko) is 40 ° C., THF is used as an eluent, the flow rate is 0.2 ml / min, detection is RI, sample concentration 0.02%, and polystyrene was used as a standard sample. The mass average molecular weight of the present invention describes the value measured by the above method.

  The glass transition temperature of the resin is preferably -20 to 100 ° C, more preferably 0 to 80 ° C. When the glass transition temperature of the resin is 100 ° C. or lower, the peel strength from the sealing material is further improved. Moreover, when glass transition temperature will be -20 degreeC or more, it will be easy to suppress blocking of protective materials.

  The glass transition temperature refers to a glass transition temperature measured by differential scanning calorimetry (DSC) for a resin having a non-volatile content of 100% by drying the resin. For example, for the glass transition temperature, an aluminum pan containing a sample weighed about 10 mg and an aluminum pan not containing a sample are set in a DSC apparatus, and this is set to −100 using liquid nitrogen in a nitrogen stream. A rapid cooling treatment is performed until the temperature is increased to 200 ° C. at 20 ° C./min, and a DSC curve is plotted. The slope of the DSC curve on the low temperature side (the DSC curve portion in the temperature region where no transition or reaction occurs in the test piece) is extended to the high temperature side, and the slope of the step change portion of the glass transition is maximized. From the intersection with the tangent drawn at such a point, the extrapolated glass transition start temperature (Tig) can be determined, and this can be determined as the glass transition temperature. The glass transition temperature of this invention has described the value measured by said method.

  Moreover, the effect of a heat-and-moisture resistance improvement can be anticipated by adding an epoxy resin (Ep) to the anchor coating agent of this invention. 0.1-70 mass parts is preferable with respect to 100 parts of resin, as for the addition amount of an epoxy resin, 0.5-60 mass parts is more preferable, and 1-50 mass parts is further more preferable. The epoxy resin is a resin having an epoxy group. Epoxy resins are not used alone but in combination with other resins.

  Examples of the epoxy resin include glycidyl ether compounds and glycidyl ester compounds.

  Examples of the glycidyl ether compound include bisphenol-type epoxy resins, novolac-type epoxy resins, biphenol-type epoxy resins, bixylenol-type epoxy resins, trihydroxyphenylmethane-type epoxy resins, and tetraphenylolethane-type epoxy resins.

  Examples of the bisphenol type epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, brominated bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin and the like.

  Examples of the novolak type epoxy resin include a phenol novolak type epoxy resin, a cresol novolak type epoxy resin, a brominated phenol novolak type epoxy resin, a naphthalene skeleton-containing phenol novolak type epoxy resin, a dicyclopentadiene skeleton containing phenol novolak type epoxy resin, and the like. .

Examples of the glycidyl ester compound include terephthalic acid diglycidyl ester.
Epoxy resins can be used alone or in combination of two or more.

The resin preferably has a functional group capable of crosslinking with the curing agent.
When the functional group is a hydroxyl group, the hydroxyl value of the resin is preferably 0.1 to 100 mgKOH / g, more preferably 1 to 50 mgKOH / g, and further preferably 2 to 30 mgKOH / g. When the hydroxyl value is 100 mgKOH / g or less, the peel strength from the sealing material is further improved. On the other hand, when the hydroxyl value is 0.1 mgKOH / g or more, the peel strength after the wet heat test is hardly lowered.
When the functional group is a carboxyl group, the acid value of the resin is preferably 0.1 to 100 mgKOH / g, more preferably 1 to 50 mgKOH / g, and further preferably 2 to 30 mgKOH / g. When the acid value is 100 mgKOH / g or less, the peel strength from the sealing material is further improved. Moreover, when the acid value is 0.1 mgKOH / g or more, the peel strength after the wet heat test is hardly lowered.

  The curing agent used in the present invention may be a compound having two or more functional groups capable of reacting with the functional group of the resin. When the curing agent crosslinks the resin, the durability is improved and the peel strength is improved.

  For example, when the resin contains a reactive functional group such as a hydroxyl group or a carboxyl group, the curing agent is preferably a compound that reacts with these functional groups. Examples of the curing agent include an isocyanate curing agent, an epoxy curing agent, a metal chelate curing agent, an aziridine curing agent, an oxazoline curing agent, and a carbodiimide curing agent. Among these, an isocyanate curing agent and an epoxy curing agent are preferable, and an isocyanate curing agent is more preferable.

  Isocyanate-based curing agents are diisocyanate compounds such as 1,3-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2 , 6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4 ', 4 "-triphenylmethane triisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), pentamethylene diisocyanate 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4′-methylenebis (Cyclohexyl isocyanate), 1,4-bis (isocyanatomethyl) cyclohexane and the like.

  Also, adducts of the above diisocyanate compounds and polyol compounds such as trimethylolpropane, burettes of the above diisocyanate compounds, isocyanurates of the above diisocyanate compounds, and further isocyanate compounds and known polyether polyols, polyester polyols, and acrylic polyols. And trifunctional or higher functional isocyanate curing agents such as adducts with polybutadiene polyol, polyisoprene polyol and the like. Among these, hexamethylene diisocyanate (HDI) isocyanurate and 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI) isocyanurate are preferred.

  It is also preferable to use a blocked isocyanate curing agent as the isocyanate curing agent. This further improves the peel strength after the wet heat resistance test.

  Examples of the blocking agent for the blocked isocyanate curing agent include phenols such as phenol, thiophenol, methylthiophenol, xylenol, cresol, resorcinol, nitrophenol, and chlorophenol; oximes such as acetone oxime, methyl ethyl ketone oxime, and cyclohexanone oxime; methanol, Ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, t-butyl alcohol, t-pentanol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, benzyl Alcohols such as alcohol; 3,5-dimethylpyrazole, 1, -Pyrazoles such as pyrazole; triazoles such as 1,2,4-triazole; halogen-substituted alcohols such as ethylene chlorohydrin and 1,3-dichloro-2-propanol; ε-caprolactam, δ-valerolactam, γ-butyrolactam, Examples include lactams such as β-propyl lactam, and active methylene compounds such as methyl acetoacetate, ethyl acetoacetate, acetylacetone, methyl malonate, and ethyl malonate. In addition, amines, imides, mercaptans, imines, ureas, diaryls, and the like are also included. The blocking agents can be used alone or in combination of two or more.

  80-150 degreeC is preferable and the dissociation temperature of a blocking agent has more preferable 90-140 degreeC. As the blocking agent, for example, methyl ethyl ketone oxime (dissociation temperature: 140 ° C., the same applies hereinafter), 3,5-dimethylpyrazole (120 ° C.), diisopropylamine (120 ° C.) and the like are more preferable.

  The spherical particles used in the present invention are preferably organic particles having an average particle diameter of 1 to 30 μm and inorganic particles. When spherical particles are used, light incident on the anchor coat layer is reflected or scattered, so that the weather resistance of the protective material is further improved. The average particle diameter of the spherical particles is more than 1 μm and more preferably 20 μm or less. In addition, since the unevenness is formed on the surface of the anchor coat layer, the contact area is increased and the peel strength is improved during thermocompression bonding (also referred to as vacuum heat lamination) with the sealing material. The spherical shape of the spherical particles was such that the ratio of the major axis diameter to the minor axis diameter of the particles was a major axis diameter / minor axis diameter (also referred to as aspect ratio) of 2 or less.

  The average particle diameter, and the particle major axis diameter and minor axis diameter are values averaged based on about 20 particles of an enlarged image (about 1,000 to 10,000 times) obtained from a scanning electron microscope.

The organic particles are preferably particles having a melting point or softening point of 100 ° C. or higher. When the melting point or softening point of the organic particles is 100 ° C. or higher, the peel strength is further improved. The upper limit of the softening point is not limited as long as it is a temperature at which desired weather resistance and peel strength can be obtained. For example, it is about 500 ° C.
As for melting | fusing point according to the raw material of organic particle | grains, 100-150 degreeC is preferable for olefin type organic particle, and 300-350 degreeC is preferable for fluorine type organic particle, for example.

  Examples of the organic particle material include polymer particles such as (meth) acrylic resin, polystyrene, nylon (registered trademark), melamine resin, benzoguanamine resin, phenol resin, urea resin, silicon resin, cellulose powder, nitrocellulose powder, wood Examples thereof include powder, waste paper powder, rice husk powder, and starch. Among these, (meth) acrylic resin, benzoguanamine resin, and melamine resin are more preferable in terms of improving peel strength.

  The organic particles can be obtained by a known polymerization method such as an emulsion polymerization method, a suspension polymerization method, a dispersion polymerization method, a soap-free polymerization method, a seed polymerization method, or a microsuspension polymerization method. Also,

Examples of the inorganic particles include inorganic particles such as titanium oxide and silica.
Spherical particles can be used alone or in combination of two or more.

  The melting point of the antioxidant used in the present invention is preferably 5 to 300 ° C, more preferably 30 to 200 ° C, and further preferably 100 to 200 ° C. The peel strength is further improved by having the melting point within a predetermined range.

  The antioxidant used in the present invention is preferably, for example, a hindered phenol-based antioxidant, a phosphorus-based antioxidant, a sulfur-based antioxidant, or the like.

  Examples of hindered phenolic antioxidants include 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, mono (or di- or tri) (α-methyl). Benzyl) phenol, 2,2′-methylenebis (4 ethyl-6-tert-butylphenol), 2,2′-methylenebis (4methyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6) -Tert-butylphenol), 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, triethyleneglycol-bis- [3- (3-tert-butyl-5-methyl-4hydroxy Phenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl- -Hydroxyphenyl) propionate], pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4 -Hydroxyphenyl) propionate, isooctyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy -Hydrocinnamamide), 3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris (3,5-di-) -T-butyl-4-hydroxybenzyl) benzene, bis (3,5-di-t-butyl-4-hydroxybenzylphosphonate ethyl) calci , Tris- (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] Hydrazine, tris (2,4-di-t-butylphenyl) phosphite, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α- Dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-tert-ami -2-hydroxyphenyl) benzotriazole, 2- (2′-hydroxy-5′-t-octylphenyl) -benzotriazole, methyl-3- [3-tert-butyl-5- (2H-benzotriazole-2- Yl) -4-hydroxyphenyl] propionate-polyethylene glycol (molecular weight about 300), condensate, hydroxyphenylbenzotriazole derivative, 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n -Butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate, 4 , 4′-thiobis (3-methyl-6-tert-butylphenol), 1,1,3-tris- (2-methyl-4-hydroxy-5) tert-butylphenyl) butane, butylidene-1,1-bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], 3,9-bis [2- [3- (3- tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, 2,2-thio-diethylene Bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], benzenepropanoic acid, 3,5-bis (1,1-dimethylethyl) -4-hydroxy, C7-C9 side chain Alkyl ester, 1,3,5-tris [(4-tert-butyl-3-hydroxy-2,6-xylyl) methyl] 1,3,5-triazine-2,4,6-trione, 2 4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2-tert-butyl-6- (3′-tert- Butyl-5′-methyl-2′-hydroxybenzyl) -4-methylphenyl acrylate, 2- [1- (2-hydroxy-3,5-di-tert-pentylphenyl) -ethyl] -4,6-di -Tert-pentylphenyl acrylate, 4,6-bis [(octylthio) methyl] o-cresol, 2,4-dimethyl-6- (1-methylpentadecyl) phenol, 3,5-di-tert-butyl-4 -Hydroxybenzylphosphonate-diethyl ester, 2,6-di-tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-yl Amino) phenol and the like.

  The hindered phenolic antioxidants are Nocrak 200, Nocrack M-17, Nocrack SP, Nocrack SP-N, Nocrack NS-5, Nocrack NS-6, Nocrack NS-30, Nocrack NS-7, NOCRACK DAH (all of which are manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.), ADK STAB AO-20, ADK STAB AO-30, ADK STAB AO-40, ADK STAB AO-50, ADK STAB AO-60, ADK STAB AO-70 and ADK STAB AO-80 , ADK STAB AO-330 (all of which are manufactured by ADEKA), IRGANOX-245, IRGANOX-259, IRGANOX-565, IRGANOX-1010, IRGANOX-1024, IRGANOX-1035, IRGANOX-1076, I GANOX-1098, IRGANOX-1135, IRGANOX-1141, IRGANOX-1222, IRGANOX-1330, IRGANOX-1425WL, IRGANOX-1520, IRGANOX-1726, IRGANOX-3114 (above, all manufactured by BASF Japan), Sumizer GM , Sumilizer GS, Sumilizer GP, Sumilizer GA-80, Sumilizer MDP-S, Sumilizer BBM, Sumilizer WX-R (all of which are manufactured by Sumitomo Chemical Co., Ltd.).

  Phosphorous antioxidants include, for example, tris (nonylphenyl) phosphite, tris (mono, dinonylphenyl) phosphite, diphenyl, mono (2-ethylhexyl) phosphite, diphenyl, mono (tridecyl) phosphite, diphenyl, mono (Isodecyl) phosphite, diphenyl, mono (isooctyl) phosphite, diphenyl, mono (nonylphenyl) phosphite, triphenyl phosphite, tris (tridecyl) phosphite, triisodecyl phosphite, tris (2,4-di t-butylphenyl) phosphite, tetraphenyldipropylene glycol-diphosphite, tetraphenyltetra (tridecyl) pentaerythritol-tetraphosphite, 1,1,3-tris (2-methyl-4-ditridecyl) Sphaito 5-t-butylphenyl) butane, 4,4′-butylidenebis (3-methyl-6-t-butyl-ditridecyl phosphite), 2,2′-methylenebis (4,6-di-t-butylphenol) Octyl phosphite, 4,4′-isopropylidene-diphenol alkyl (C12-C15) phosphite, cyclic neopentanetetrayl bis (2,4-di-t-butylphenyl phosphite), cyclic neopentanetetrayl bis ( 2,6-di-t-butyl-4-methylphenyl phosphite), cyclic neopentanetetraylbis (nonylphenyl phosphite), bis (nonylphenyl) pentaerythritol diphosphite, distearyl, pentaerythritol, diphosphite, bis [2,4-Bis (1,1′-dimethylethyl ) -6-methylphenyl] ethyl ester phosphite.

  Commercially available hindered phenol antioxidants include ADK STAB 1178, ADK STAB 329K, ADK STAB 135A, ADK STAB C, ADK STAB TPP, ADK STAB 3010, ADK STAB 2112, ADK STAB 522A, ADK STAB 260, ADK STAB HP-10, ADK STAB 1500, and ADK STAB 1500. PEP-24-G, ADK STAB PEP-36, ADK STAB PEP-4C, ADK STAB PEP-8 (all of which are made by ADEKA), JPM-308, JPM-313, JPM-333E, JPP-100, JPP-613M, JPP- 31 (all of which are manufactured by Johoku Chemical Co., Ltd.), CHELEX-M, (manufactured by Sakai Chemical Co., Ltd.), IRGAFOS38 (manufactured by BASF Japan Ltd.) and the like.

Sulfur-based antioxidants can be widely used conventionally known ones. From the viewpoint of improving the curability of the resin, a sulfur-based antioxidant having a thioether structure in the molecule is preferable.
Examples of the sulfur-based antioxidant include 4,4′-thiobis (3-methyl-6-tert-butylphenol), dilauryl-thiodipropionate, bis [2-methyl-4- [3-n-alkyl (C12 or C14 thiopropionyloxy] -5-tert-butylphenyl] sulfide, pentaerythrityl-tetrakis (3-laurylthiopropionate), ditridecyl-3,3′-thiodipropionate, distearyl-thiodipropionate, 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 4,6-bis [(octylthio) methyl] o-cresol, 2,4-bis -(N-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazi , Dimyristyl-3,3′-thiodipropionate, dibutylmethylene-bis-thioglucolate and the like.

A crosslinking accelerator can be further added to the anchor coating agent as long as the problem can be solved. The crosslinking accelerator serves as a catalyst that promotes the reaction between the resin and the curing agent. The crosslinking accelerator is preferably a tin compound, a metal salt, a base, etc., for example, tin octylate, dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, tin chloride, iron octylate, cobalt octylate, zinc naphthenate, triethylamine, triethylamine Examples include ethylenediamine.
The crosslinking accelerator can be used alone or in combination of two or more.

In addition, a pigment can be further added to the anchor coating agent in addition to the spherical particles as long as the problem can be solved. Examples of the pigment include inorganic pigments and organic pigments.
Examples of the inorganic pigment include carbon black, titanium oxide, and calcium carbonate.
Organic pigments include, for example, insoluble azo pigments such as toluidine red, toluidine maroon, Hansa yellow, benzidine yellow, and pyrazolone red; soluble azo pigments such as lithol red, heliobordeaux, pigment scarlet, and permanent red 2B; alizarin, indanthrone, thioindigo Derivatives from vat dyes such as maroon; Phthalocyanine organic pigments such as phthalocyanine blue and phthalocyanine green; Quinacridone organic pigments such as quinacridone red and quinacridone magenta; Perylene organic pigments such as perylene red and perylene scarlet; Isoindolinone yellow , Isoindolinone organic pigments such as isoindolinone orange; pyranthrone organic pigments such as pyranthrone red and pyranthrone orange, thioindigo organic pigments Condensed azo organic pigments, benzimidazolone organic pigments, quinophthalone organic pigments such as quinophthalone yellow; isoindoline organic pigments such as isoindoline yellow: Other pigments include flavanthrone yellow, acylamide yellow, nickel azo yellow, Examples include copper azomethine yellow, perinone orange, anthrone orange, dianslaquinonyl red, and dioxazine violet.

  When a pigment is used, it is preferable to add a dispersant at the same time. Thereby, the dispersibility of the pigment can be improved, and the storage stability of the anchor coating agent can be improved.

  Examples of the dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a salt of a long chain polyaminoamide and a polar acid ester, a high molecular weight unsaturated acid ester, Molecular copolymer, modified polyurethane, modified polyacrylate, polyether ester type anionic activator, naphthalene sulfonic acid formalin condensate salt, aromatic sulfonic acid formalin condensate salt, polyoxyethylene alkyl phosphate ester, polyoxyethylene nonyl Examples include phenyl ether and stearylamine acetate.

A solvent can be added to the anchor coating agent of the present invention.
Examples of the solvent include alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol methyl ether, and diethylene glycol methyl ether;
Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone;
Ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether;
Hydrocarbons such as hexane, heptane, octane;
Aromatics such as benzene, toluene, xylene, cumene;
And esters such as ethyl acetate and butyl acetate. Among these, a solvent having a boiling point of 50 ° C to 200 ° C is preferable. When the boiling point is 50 ° C. or higher, it is easy to form an anchor coat layer having a uniform thickness by coating. Moreover, when the boiling point is 200 ° C. or lower, the drying property at the time of coating is further improved.
The solvent can be used alone or in combination of two or more.

  As necessary, the anchor coating agent of the present invention includes a filler, a thixotropy imparting agent, an anti-aging agent, an antistatic agent, a flame retardant, a thermal conductivity improving agent, a plasticizer, an anti-sagging agent, an antifouling agent, and an antiseptic. Various additives such as agents, bactericides, antifoaming agents, leveling agents, curing agents, thickeners, pigment dispersants, silane coupling agents, peroxides, and azo compounds may be added.

  The anchor coating agent of the present invention can be used not only for solar cell applications but also for improving the peel strength between various other adherends and substrates. Specific applications include, for example, UV curable printing inks and UV curable hard coat agents.

  The protective material of the present invention includes a base material and an anchor coat layer containing an anchor coat agent. The anchor coat layer can be formed by applying an anchor coat agent on the substrate.

  As a method for applying the anchor coating agent to the substrate, a known method can be used. Examples of the coating method (coating apparatus) include comma coating, gravure coating, reverse coating, roll coating, lip coating, and spray coating. It is preferable to perform heat drying (for example, a hot air heater or an infrared heater) during coating.

The substrate is preferably glass or a plastic film.
Examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate;
Olefin films such as polyethylene, polypropylene, polycyclopentadiene;
Fluorine-based films such as polyvinyl fluoride, polyvinylidene fluoride film, polytetrafluoroethylene film, and ethylene-tetrafluoroethylene resin film;
An acrylic film, a triacetyl cellulose film, etc. are mentioned.
The base material may have a multilayer structure of two or more layers, and a vapor deposition layer in which a metal oxide or a nonmetal inorganic oxide is vapor deposited may be laminated. Furthermore, the substrate may be transparent or colored.
The thickness of the substrate is usually about 10 to 300 μm.

  The thickness of the anchor coat layer is usually about 0.1 to 30 μm.

  The protective material of the present invention is preferably used as a protective material (surface protective material or back surface protective material) constituting the solar cell module.

The solar cell module of the present invention has a configuration in which a surface protective material, a surface sealing material, a solar battery cell, a back surface sealing material, and a back surface protective material are laminated in this order from the sunlight receiving side.
A typical configuration of the solar cell module will be described based on the cross-sectional view of FIG. 1. The surface protective material 1 positioned on the light receiving surface side of the solar cell element 3 is laminated via the surface sealing material 2, and the back surface protective material 5. Can be produced by thermocompression-bonding a laminate obtained by laminating through a back surface sealing material 4 positioned on the non-light-receiving surface side of the solar battery cell.

  The thermocompression bonding conditions are, for example, vacuum degassing at 140 ° C. to 170 ° C. for about 3 to 10 minutes, and then pressure bonding at atmospheric pressure for about 10 to 50 minutes while maintaining the temperature. After thermocompression bonding, if necessary, it may be put into an oven at 100 to 200 ° C. and heated for about 5 to 60 minutes. By the thermocompression bonding, cross-linking of the sealing material, polymerization of the protective material, etc. proceed, and it adheres strongly.

  Examples of the surface protective material 1 include a glass plate, a plastic plate of polycarbonate or polyacrylate, and the like. Among these, glass having excellent weather resistance is preferable.

  The front surface sealing material 2 and the back surface sealing material 4 are preferably EVA, an olefin film, or the like. These sealing materials contain an ultraviolet absorber and a light stabilizer for improving the weather resistance. In particular, when EVA is used, it generally contains a peroxide or the like in order to crosslink the sealing material itself.

  Examples of the solar cell element 3 include an element in which an electrode is provided on a photoelectric conversion layer such as a compound semiconductor typified by crystalline silicon, amorphous silicon, or copper indium selenide. The element may be formed on a substrate such as glass.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by a following example. In addition, in an Example, a part shows a mass part. Moreover,% shows the mass%.

  The glass transition temperature, acid value, and hydroxyl value were measured as described below.

<Measurement of glass transition temperature (Tg)>
The glass transition temperature was measured by the differential scanning calorimetry (DSC) method described above.
In addition, the sample for Tg measurement used the non-volatile part which heated the resin solution to measure at 150 degreeC for about 15 minutes, and was made to dry.

<Measurement of acid value>
About 1 g of a sample (resin solution: about 50%) is accurately weighed in a stoppered Erlenmeyer flask, and 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixed solution is added and dissolved. To this is added phenolphthalein reagent as an indicator and held for 30 seconds. Thereafter, the solution is titrated with a 0.1N alcoholic potassium hydroxide solution until the solution becomes light red.
The acid value was determined by the following formula. The acid value was a numerical value of the dry state of the resin (unit: mgKOH / g).
Acid value (mgKOH / g) = {(5.611 × a × F) / S} / (Nonvolatile content concentration / 100)
Where S: Amount of sample collected (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)
F: Potency of 0.1N alcoholic potassium hydroxide solution

<Measurement of hydroxyl value>
About 1 g of a sample is accurately weighed in a stoppered Erlenmeyer flask, and 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixed solution is added and dissolved. Further, exactly 5 ml of an acetylating agent (a solution in which 25 g of acetic anhydride was dissolved in pyridine to make a volume of 100 ml) was added and stirred for about 1 hour. To this, phenolphthalein reagent is added as an indicator and lasts for 30 seconds. Thereafter, the solution is titrated with a 0.5N alcoholic potassium hydroxide solution until the solution becomes light red.
The hydroxyl value was determined by the following formula. The hydroxyl value was a numerical value in the dry state of the resin (unit: mgKOH / g).
Hydroxyl value (mgKOH / g)
= [{(B−a) × F × 28.05} / S] / (Nonvolatile content concentration / 100) + D
Where S: Amount of sample collected (g)
a: Consumption of 0.5N alcoholic potassium hydroxide solution (ml)
b: Consumption of the 0.5N alcoholic potassium hydroxide solution in the blank experiment (ml)
F: Potency of 0.5N alcoholic potassium hydroxide solution D: Acid value (mgKOH / g)

<Synthesis Example 1 (Meth) acrylic resin (A1)>
Into a four-necked flask equipped with a cooling tube, a stirrer, a thermometer, and a nitrogen introduction tube were charged 50 parts of toluene and 50 parts of methyl ethyl ketone, and the temperature was raised to 100 ° C. in a nitrogen atmosphere. Next, 28 parts of methyl methacrylate, 20 parts of cyclohexyl methacrylate, 12 parts of butyl acrylate, 20 parts of n-butyl methacrylate, 15 parts of t-butyl methacrylate, 5 parts of 2-hydroxyethyl methacrylate, and 0.30 part of azobisisobutyronitrile. The monomer liquid containing was charged into the dropping funnel, and the monomer liquid was continuously dropped over 2 hours. Subsequently, 0.12 part of azobisisobutyronitrile was divided into three portions in the flask and added every hour to conduct a polymerization reaction, and the reaction was continued for another hour. After completion of the reaction, cooling is performed, and the weight average molecular weight is 200,000, the hydroxyl value is 22.0 (mgKOH / g), the acid value is 0 (mgKOH / g), the Tg is 53 ° C., and the non-volatile content is 50% (meta ) Acrylic resin (A1) solution was obtained.

<Synthesis Example 2 Polyurethane (A2)>
In a four-necked flask equipped with a cooling tube, a nitrogen introducing tube, a stirring device, a thermometer, and a dropping funnel, 355 parts of C-2090 (manufactured by Kuraray Co., Ltd., polycarbonate polyol), 11 parts of cyclohexanedimethanol, xylylene diisocyanate 34 And 100 parts of toluene were charged, 0.03 part of dibutyltin dilaurate was added as a catalyst, and the temperature was gradually raised to 100 ° C., followed by reaction for 3 hours. After confirming the absence of an NCO peak by IR measurement, 300 parts of ethyl acetate was added, the weight average molecular weight was 40,000, the hydroxyl value was 13.8 (mgKOH / g), the Tg was 8 ° C., and the non-volatile content was 50 % Polyurethane (A2) solution was obtained.

<Synthesis Example 3 (Meth) acrylic resin (A3)>
In a four-necked flask equipped with a condenser, a stirrer, a thermometer, and a nitrogen inlet tube, 41 parts of methyl methacrylate, 55 parts of n-butyl methacrylate, 2 parts of 2-hydroxyethyl methacrylate, 2 parts of glycidyl methacrylate, and 100 parts of toluene The temperature was raised to 100 ° C. while stirring in a nitrogen atmosphere, and 0.15 part of azobisisobutyronitrile was added to conduct a polymerization reaction for 2 hours. Next, 0.07 part of azobisisobutyronitrile was added, and the polymerization reaction was further performed for 2 hours. Next, 0.07 part of azobisisobutyronitrile was added, and the polymerization reaction was further performed for 2 hours.
Thereafter, 0.03 part of hydroquinone, 0.8 part of dimethylbenzylamine and 1 part of acrylic acid were added to give a carbon-carbon double bond to the side chain, and the mixture was heated and stirred at 100 ° C. for 15 hours. The reaction was terminated after confirming that the acid value was 2 (mgKOH / g) and below. A (meth) acrylic resin (A3) solution having a weight average molecular weight of 80,000, a hydroxyl value of 8.5 (mgKOH / g), a Tg of 51 ° C. and a nonvolatile content of 50% was obtained.

<Polyisocyanate compound (B)>
The isocyanurate form of hexamethylene diisocyanate blocked with 3,5-dimethylpyrazole was diluted to 75% with ethyl acetate to obtain a polyisocyanate compound solution (B).

<Anchor coating agent solution 1>
80 parts of a (meth) acrylic resin (A1) solution and Irganox 1010 (made by BASF, [3- [3- (3,5-di-t-butyl-4-hydroxyphenyl) as a hindered phenol antioxidant ) Propanoyloxy] -2,2-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propanoyloxymethyl] propyl] 3- (3,5-di-t-butyl- 4-hydroxyphenyl) propanate) is 3 parts by mass with respect to 100 parts by mass of the resin, and Epester L15 (Nippon Shokubai Co., Ltd., benzoguanamine / formaldehyde condensate) having an average particle size of 9 μm as spherical particles is 3 with respect to 100 parts by mass of the resin. A solution prepared by mixing part by weight of an isocyanate curing agent solution (B) so that the NCO / OH molar ratio is 1.5 is diluted to 25% with ethyl acetate, and It was a car coating agent solution 1.

<Anchor coating agent solution 2>
The (meth) acrylic resin (A1) solution of the anchor coating agent solution 1 is changed to a polyurethane (A2) solution, the antioxidant is 10 parts by mass with respect to the resin 100, and the spherical particles are 10 parts by mass with respect to the resin 100. An anchor coating agent solution 2 was prepared in the same manner as the anchor coating agent solution 1 except that the change was changed to.

<Anchor coating agent solution 3>
The (meth) acrylic resin (A1) solution of the anchor coating agent solution 1 is changed to a polyurethane (A2) solution, the antioxidant is 18 parts by mass with respect to the resin 100, and the spherical particles are 18 masses with respect to the resin 100. An anchor coating agent solution 2 was produced in the same manner as the anchor coating agent solution 1 except that the part was changed to the part.

<Anchor coating agent solution 4>
The anchor coating agent solution 4 is produced in the same manner as the anchor coating agent solution 2 except that the (meth) acrylic resin (A1) solution of the anchor coating agent solution 2 is changed to the (meth) acrylic resin (A3) solution. did.

<Anchor coating agent solution 5>
The antioxidant of the anchor coating agent solution 1 is changed to phosphorus antioxidant; ADK STAB 2112 (manufactured by ADEKA, tris (2,4-di-t-butylphenyl) phosphite), and the antioxidant is changed to resin 100 On the other hand, an anchor coating agent solution 5 was produced in the same manner as the anchor coating agent solution 1 except that 10 parts by mass and the spherical particles were changed to 10 parts by mass with respect to the resin 100.

<Anchor coating agent solution 6>
The antioxidant of the anchor coating agent solution 1 is changed to a sulfur-based antioxidant; DLTP “Yoshitomi” (manufactured by Mitsubishi Chemical Corporation, dilauryl-thiodipropionate), and the antioxidant is 10 parts by mass with respect to the resin 100. An anchor coating agent solution 6 was prepared in the same manner as the anchor coating agent solution 1, except that the spherical particles were changed to 10 parts by mass with respect to the resin 100.

<Anchor coating agent solution 7>
An anchor coating agent solution 7 was prepared in the same manner as the anchor coating agent solution 1 except that the amount of the hindered phenolic antioxidant in the anchor coating agent solution 1 was changed to 30 parts with respect to 100 parts by mass of the resin.

<Anchor coating agent solution 8>
An anchor coating agent solution 8 was prepared in the same manner as the anchor coating agent solution 1 except that the amount of spherical particles of the anchor coating agent solution 1 was changed to 30 parts with respect to 100 parts by mass of the resin.

<Anchor coating agent solution 9>
The antioxidant of the anchor coating agent solution 1 is changed to Irganox 1135 (manufactured by BASF, octyl-3,5-di-tert-butyl-4-hydroxy-hydrosilicic acid), and the antioxidant is 10 with respect to the resin 100. An anchor coating agent solution 9 was prepared in the same manner as the anchor coating agent solution 1 except that the mass parts and spherical particles were changed to 10 parts by mass with respect to the resin 100.

<Anchor coating agent solution 10>
The antioxidant of anchor coating solution 1 was changed to Irganox 1330 (BASF, 2,4,6-tris (3 ′, 5′-di-t-butyl-4′-hydroxybenzyl) mesitylene) to prevent oxidation An anchor coating agent solution 10 was prepared in the same manner as the anchor coating agent solution 1 except that the agent was changed to 10 parts by mass with respect to the resin 100 and the spherical particles were changed to 10 parts by mass with respect to the resin 100.

<Anchor coating agent solution 11>
The spherical particles of the anchor coating agent solution 1 are changed to MX-3000 (manufactured by Soken Chemical Co., Ltd., acrylate resin), the antioxidant is 10 parts by mass with respect to the resin 100, and the spherical particles are 10 parts by mass with respect to the resin 100. An anchor coating agent solution 11 was produced in the same manner as the anchor coating agent solution 1 except that the changes were made.

<Anchor coating agent solution 12>
The spherical particles of the anchor coating agent solution 1 are changed to Eposter S12 (manufactured by Nippon Shokubai Co., Ltd., melamine / formaldehyde condensate), the antioxidant is 10 parts by mass with respect to the resin 100, and the spherical particles are 10 masses with respect to the resin 100. An anchor coating agent solution 12 was produced in the same manner as the anchor coating agent solution 1 except that the part was changed to the part.

<Anchor coating agent solution 13>
An anchor coating agent solution 13 was prepared in the same manner as the anchor coating agent solution 1, except that the antioxidant of the anchor coating agent solution 1 was not added and the spherical particles were changed to 10 parts by mass with respect to the resin 100.

<Anchor coating agent solution 14>
The spherical particles of the anchor coating agent solution 1 are changed to Eposter SS (manufactured by Nippon Shokubai Co., Ltd., melamine / formaldehyde condensate), the antioxidant is 10 parts by mass with respect to the resin 100, and the spherical particles are 10 masses with respect to the resin 100. An anchor coat agent solution 14 was produced in the same manner as the anchor coat agent solution 1 except that the parts were changed to parts.

<Anchor coating agent solution 15>
An anchor coating agent solution 15 was prepared in the same manner as the anchor coating agent solution 1, except that the spherical particles of the anchor coating agent solution 1 were not added and the antioxidant was changed to 10 parts by mass with respect to the resin 100.

<Anchor coating agent solution 16>
The spherical particles of the anchor coating agent solution 1 are changed to flat particles RL-217 (made by Fuji Talc Kogyo Co., Ltd., talc), the antioxidant is 10 parts by mass with respect to the resin 100, and the spherical particles are with respect to the resin 100. The anchor coating agent solution 16 was prepared in the same manner as the anchor coating agent solution 1 except that the amount was changed to 10 parts by mass.

  Table 1 shows an outline of the raw materials blended in the anchor coating agent solutions 1 to 16.

[Example 1]
<Peel strength test>
The anchor coating agent solution 1 is applied to a corona-treated surface of a 188 μm thick polyester film (Lumirror X10S manufactured by Toray Industries, Inc.) using a gravure coater, and the solvent is dried at 100 ° C. for 1 minute. An anchor coat layer was provided. Two EVA sheets with a thickness of 400 μm and a white plate glass plate are stacked on the anchor coat layer, and a white plate glass is placed on a hot plate of a module laminator PVL0505S (Nisshinbo Mechatronics) heated to 140 ° C. It was placed on the bottom and evacuated to about 1 Torr and left for 5 minutes. Next, the sample was pressed at atmospheric pressure while maintaining 140 ° C., and allowed to stand for 15 minutes to prepare a measurement sample. The polyester film surface of the obtained measurement sample was cut into a width of 15 mm with a cutter so as to reach the white plate glass, and the initial peel strength between the anchor coating agent and the EVA film was measured. For the measurement, a 180 ° peel test was performed using a tensile tester at a load speed of 100 mm / min. The obtained measurement values were evaluated as follows.
☆: 70 N / 15 mm or more Excellent ◎: 50 N / 15 mm or more and less than 70 N / 15 mm Good ○: 30 N / 15 mm or more and less than 50 N / 15 mm Practical range Δ: 10 N / 15 mm or more and less than 30 N / 15 mm Impractical use ×: Less than 10 N / 15 mm Impractical

<Weather resistance test>
A stainless steel (SUS) plate having a thickness of 1 mm was placed on the measurement sample prepared in the same manner as described above to cover half the area of the measurement sample. Next, using a super xenon weather meter (manufactured by Suga Test Instruments Co., Ltd.), a 1000 cy time test was performed on the part covered with the SUS plate and the exposed part under the following conditions. For the anchor coat layer of the measurement sample after the lapse of time, an adhesion test (cross-cut method), a yellowing degree evaluation, and a film reduction evaluation were performed.
-Aging condition 1) 63 ° C 95% 160W / m2 irradiation + rainfall 12min
2) 63 ° C 50% 160W / m2 irradiation 108min
3) 1) and 2) were repeated for 1000 cy with 1 cy (cycle).

<Adhesion>
According to JIS K-5400, the anchor coating layer of the exposed portion of the obtained measurement sample after the lapse of time was half-cut into 11 mm rows and 11 rows at 1 mm width intervals to form a sample having a total of 100 squares. . Next, the cellophane tape was peeled off immediately after being applied from above the sample, and the remaining state of the anchor coat layer was visually observed and evaluated according to the following criteria.
A: 95% or more of 100% remained in 100 squares. Good Δ: 50% or more and less than 95 remained in 100 squares. Practical impossibility x: Less than 50% of 100 squares remained. Impractical

<Yellowness>
The yellowing degree was measured using a color difference meter CR-300 (manufactured by Konica Minolta) for the anchor coat layer in the exposed portion of the obtained measurement sample after the lapse of time according to the method described in JIS-Z8722, and L * a * Evaluation was based on the Δb value when expressed in the b * color system. It can be said that the smaller the change in b value, the less yellowing.
◎: Δb value of less than 2 Good ○: Δb value of 2 or more and less than 4 Practical use range Δ: Δb value of 4 or more Impractical use ×: Δb value of 10 or more Impractical use

<Reduced film>
The decrease in thickness due to the decomposition of the anchor coat layer was evaluated as the film reduction. The difference in thickness between the portion covered with the SUS plate and the portion not covered with the obtained measurement sample after the lapse of time was evaluated as film thickness reduction.
◎: Film reduction is less than 1 μm Good ○: Film reduction is 1 μm or more and 5 μm or less Practical use Δ: Film reduction is 5 μm or more and 10 μm or less Impractical ×: Film reduction is 10 μm or more Impractical

[Examples 2 to 12], [Comparative Examples 1 to 4]
Except for changing the anchor coating agent 1 of Example 1 to anchor coating agent solutions 2 to 16 respectively, the peel strength and weather resistance were evaluated in the same manner as in Example 1, and Examples 2 to 12 and Comparative Examples 1 to 4 were evaluated. Evaluation results were obtained. The evaluation results are shown in Table 2.

  From the results of Table 2, in Examples 1 to 12, the back surface protective material for solar cells using the anchor coating agent solution of the present invention had sufficient peel strength with respect to the EVA film. This forms irregularities on the surface of the anchor coating agent layer by using spherical particles having an average particle diameter of 1 to 30 μm. The unevenness increases the contact area between the EVA and the anchor coat layer during vacuum heat lamination, thereby improving the peel strength.

  In Examples 1 to 12, sufficient weather resistance was obtained with respect to the super xenon weather meter. In addition to improving the weather resistance by adding an antioxidant, the presence of spherical particles can suppress the deterioration of the anchor coat agent layer, thus scattering incident light. , Weather resistance is improved.

  On the other hand, since the comparative example 1 does not contain an antioxidant, the weather resistance is inferior. Since Comparative Example 2 uses spherical particles of less than 1 μm, sufficient unevenness cannot be formed on the surface of the anchor coat layer, and the peel strength is inferior. Since Comparative Example 3 does not contain spherical particles, the peel strength and weather resistance are inferior. Since Comparative Example 4 uses talc of flat particles instead of spherical particles, the peel strength is inferior.

1: Surface protective material 2: Surface sealing material 3: Solar cell element 4: Back surface sealing material 5: Back surface protective material

Claims (6)

  A solar cell anchor coating agent comprising a resin, a curing agent, spherical particles having an average particle diameter of 1 to 30 μm, and an antioxidant.   The anchor coating agent for solar cells according to claim 1, comprising 0.1 to 20 parts by mass of the antioxidant with respect to 100 parts by mass of the resin.   The anchor coating agent for solar cells according to claim 1 or 2, comprising 0.1 to 20 parts by mass of the spherical particles with respect to 100 parts by mass of the resin.   The anchor coating agent for solar cells according to any one of claims 1 to 3, wherein the antioxidant has a melting point of 30 to 200 ° C. It is a protective material used for a solar cell module provided with a solar cell, a sealing material, and a protective material,
The protective material provided with the anchor coat layer which consists of hardened | cured material of the anchor coat agent for solar cells containing resin, a hardening | curing agent, a spherical particle with an average particle diameter of 1-30 micrometers, and antioxidant on the surface. A solar cell module laminated in the order of a surface protective material, a surface sealing material, a solar battery cell, a back surface sealing material, and a back surface protective material from the sunlight receiving side,
At least one of the surface protective material and the back surface protective material was provided with an anchor coat layer made of a cured product of a solar cell anchor coating agent containing a resin, a curing agent, spherical particles having an average particle diameter of 1 to 30 μm, and an antioxidant. , Solar cell module.

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