JP2019128387A - Method for fixing infrared-reflective dark protection sheet - Google Patents

Abstract

To provide a method for fixing a defect inevitably occurring in a manufacturing stage, for example, an infrared-reflective dark protective sheet that can be used in a back surface protective sheet for a solar cell module.SOLUTION: The fixing method is a fixing method for infrared-reflective dark protective sheet on which a dark adhesive layer 12 containing an organic dark pigment transmitting a wavelength of 750nm or more 1500nm or less is formed near infrared rays on one side of a white resin substrate layer 11, includes a step of applying an aqueous dark fixing ink in a manner of covering the missing portion 13 generated in the layer of the dark adhesive layer 12, and the aqueous dark fixing ink mainly consists of an olefin resin and the organic dark pigment described above and has an aqueous dispersion of a 1-component type of an aqueous medium as a solvent.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for correcting an infrared reflective dark color protective sheet. Specifically, an infrared reflective dark color mainly used as a back surface protection sheet for a solar cell module and having a dark appearance, but having a dark layer transmitting near infrared rays and a white layer reflecting the same The present invention relates to a method of correcting a defect which inevitably occurs in a material resin in a production step in a protective sheet.

  BACKGROUND OF THE INVENTION In recent years, solar cells as clean energy sources have attracted attention due to rising awareness of environmental issues. Generally, in a solar cell module constituting a solar cell, a transparent front substrate, a sealing material sheet on the light receiving surface side, a solar battery element, a sealing material sheet on the non-light receiving surface side, and a back surface protection sheet are laminated in order from the light receiving surface It has a function to generate electricity when sunlight enters the solar cell element.

  By the way, there are cases where the solar cell module is required to have a black or a similar dark appearance (herein also collectively referred to as "dark" in the present specification) mainly for the purpose of improving the design. In this case, also for the back surface protection sheet disposed on the outermost surface of the above solar cell module, at least the surface on the light receiving surface side has a dark appearance similar to that of the other exposed portions. Is required.

  In order to meet such demands, various dark color systems that do not absorb near infrared rays, such as oxazine pigments, instead of conventional carbon black as a coloring material for coloring the back surface protection sheet for solar cell modules in a dark color There is proposed a dark ink prepared by blending the organic pigment of (1) and (2). A dark layer for satisfying design requirements is configured to contain these infrared-transmissible dark inks, thereby reflecting near-infrared rays transmitted through this layer such as a white resin base material and the like. By making it reflect by making it contribute to power generation, the appearance of dark color which is excellent in the designability can be given to the whole solar cell module, avoiding the fall of power generation efficiency.

  On the other hand, the back surface protection sheet has an original role of preventing moisture (water vapor) from entering from the back surface side in the solar cell module. In order to achieve this, the back surface protection sheet is required to have high adhesion with the non-light-receiving surface side sealing material sheet constituting the solar cell module. As a material that can meet this requirement well, there has been proposed a back surface protection sheet in which adhesiveness is enhanced by forming a dark-colored easy-adhesion layer (primer layer) on the surface of a resin substrate (see Patent Document 3).

  Here, in order to obtain a dark-colored back surface protection sheet excellent in adhesion and still satisfying the above-mentioned design requirements, the basic layer configuration is disclosed in Patent Document 3 and the back surface protection sheet. Similarly, a dark-colored organic pigment disclosed in Patent Document 1 or 2 is added to the easily dark colored adhesive layer of the back protective sheet, thereby forming a dark easily adhesive layer on the surface of the back protective sheet. Is considered.

  However, in the back surface protection sheet having the above-mentioned configuration, when the dark color adhesion layer contains the organic dark pigment disclosed in Patent Document 1 or 2, the white resin base layer It is recognized as a problem that some minute defects of dark easy adhesion layer derived from defects in production of base film made of polyethylene terephthalate (PET) etc. used as It came to In addition, defects such as so-called fish eyes caused by mixing of foreign substances such as foreign matter and ungelled particles at the stage of producing the base film can be completely eliminated at the stage of producing the base film, It was also the conventional technical common sense that it was practically extremely difficult (see Patent Document 4).

  In the present specification, fine voids and defects in the dark easy adhesion layer are collectively referred to as “defects”. An effective method for correcting such defects has not been implemented yet, and the vacated part is currently discarded, which is manufactured using expensive functional pigments. In the protective sheet for solar cells, it has been strongly desired to take some improvement measures for this problem in terms of economy.

JP, 2010-199555, A International Publication No. 2016/052641 International Publication No. 2012/133748 Japanese Patent Laid-Open No. 7-229851

  An object of the present invention is, for example, to provide an infrared reflective dark protective sheet that can be preferably used for a back protective sheet for a solar cell module, with a method of repairing a defect which inevitably occurs in the production stage.

  The inventors of the present invention conducted intensive studies to solve the above problems, and as a result, the main component is a composition that forms defects in the easily dark-colored adhesive layer formed on the outermost surface of the protective sheet. The present inventors have found that the above-mentioned problems can be solved by a correction method using the aqueous dispersion as described above as an infrared transparent correction ink, and have completed the present invention. More specifically, the present invention provides the following.

  (1) An infrared reflective dark color in which a dark easy adhesion layer comprising an olefin resin and an organic dark pigment transmitting near infrared rays with a wavelength of 750 nm to 1500 nm is formed on one side of the white resin base layer A method of correcting a protective sheet, comprising the step of applying an aqueous dark correction ink in the form of covering a defect generated in the layer of the dark easy-adhesion layer, the aqueous dark correction ink comprising the olefin The correction method is a one-component aqueous dispersion having a resin as a main component and the organic dark pigment as main components and an aqueous medium as a solvent.

  (2) The organic dark color pigment comprises a brown pigment and a phthalocyanine pigment, and the brown pigment is a benzimidazolone pigment, 4-[(2,5-dichlorophenyl) azo]- 3-hydroxy-N- (2,5-dimethoxyphenyl) -2-naphthalenecarboxamide, 1-[(4-nitrophenyl) azo] -2-naphthalenol, bis [3-hydroxy-4- (phenylazo) -2- Naphthalenecarboxylic acid] copper salt, C.I. I. Pigment Brown 7, N, N'-bis (2,4-dinitrophenyl) -3,3'-dimethoxy-1,1'-biphenyl-4,4'-diamine, 3,4,9,10-perylenetetracarboxylic acid Diimide, Δ2,2 ′ (1H, 1′H) -binaphtho [2,1-b] thiophene-1,1′-dione and N, N ′-(10,15,16,17-tetrahydro-5,10 At least one pigment selected from the group consisting of (15,17-tetraoxo)-(5H-dinaphtho [2,3-a: 2′3′-i] carbazole-4,9-diyl) bis (benzamide) The correction method according to (1).

  (3) The correction method as described in (1) or (2) whose said olefin resin is unsaturated carboxylic acid or its anhydride, and is a C2-C6 alkene.

  (4) The correction method according to any one of (1) to (3), wherein the solvent contains an organic solvent as an auxiliary solvent in a content range of less than 50 parts by mass per 100 parts by mass of the solvent.

  (5) The method for correcting an infrared reflective dark color protective sheet according to any one of (1) to (4), wherein a base resin of the white resin base material layer is a polyester resin.

  (6) A method for producing an infrared-reflective dark color protective sheet, comprising a step of correcting the defective portion by the correction method according to any one of (1) to (5).

  (7) The manufacturing method of the infrared reflective dark color protection sheet for solar cell modules as described in (6) including the winding process of the material sheet by a roll-to-roll system.

  According to the present invention, for example, an infrared reflective dark color protective sheet that can be preferably used for a back surface protective sheet for a solar cell module is provided with a method for correcting a defect portion inevitably generated in the manufacturing stage.

It is sectional drawing which shows typically the aspect of the cross section of the protective sheet corrected by the correction method of the infrared reflective dark protection sheet of this invention. It is sectional drawing which shows typically the laminated constitution of the solar cell module which can be comprised using the protective sheet shown in FIG.

  Hereinafter, the correction method of the infrared reflective dark color protection sheet of this invention is demonstrated. However, in order to facilitate understanding of the present invention, first, an infrared reflective dark protective sheet for a solar cell module, which is an object of the correction method of the present invention, and a solar cell module using the same will be described. Then, the correction method of this invention is demonstrated. The present invention is not limited to the embodiments described below.

<Solar cell module>
First, a general layer configuration of a solar cell module 10 using an infrared reflective dark color protective sheet 1 which is a representative implementation object of the method for correcting an infrared reflective dark color protective sheet of the present invention as a back surface protective sheet will be described. To do. As shown in FIG. 2, this solar cell module 10 includes, from the light receiving surface side, the transparent front substrate 2, the sealing material sheet 3 on the light receiving surface side, the solar cell element 4, the sealing material sheet 5 on the non-light receiving surface side, As the back surface protective sheet, the infrared reflective dark color protective sheet 1 is laminated in order.

[Method for manufacturing solar cell module]
The solar cell module 10 can be manufactured by integrating the above-described constituent members by thermocompression bonding, for example, by vacuum heat laminating. In this case, the laminating temperature is preferably in the range of 130 ° C to 190 ° C. The laminating time is preferably in the range of 5 minutes to 60 minutes, particularly preferably in the range of 8 minutes to 40 minutes.

<Infrared reflective dark protection sheet>
Next, the infrared reflective dark color protective sheet 1 which is a typical implementation object of the method for correcting the infrared reflective dark color protective sheet of the present invention will be described. As shown in FIG. 1, the infrared reflective dark color protective sheet 1 is formed on one side of a white resin base material layer 11 having a “function of reflecting near infrared rays” having a wavelength of 750 nm to 1500 nm, and the white resin base material layer 11. It is a resin sheet comprised including the dark-colored easy-adhesion layer 12 which has a "function which permeate | transmits a near-infrared ray", although it exhibits the appearance of a "dark color." The method for correcting an infrared reflective dark color protective sheet of the present invention targets at least an infrared reflective dark color protective sheet comprising the above-described layer structure.

  Here, the "function to reflect near infrared radiation" in the present specification more specifically means a function having an average reflectance of 50% or more in a wavelength range of about 850 nm to 1500 nm. In addition, relative reflectance with the comparison standard sample is usually used for the above-mentioned reflectance. In the present invention, barium sulfate is used as a comparative standard sample. For the reflectance in the present invention, an integrating sphere attachment (for example, ISR 2200 manufactured by Shimadzu Corporation) is attached to a spectrophotometer (for example, Shimadzu Corporation UV 2450), barium sulfate is used as a standard plate, and a standard plate is 100 It is a value obtained by measuring the relative reflectance in%.

  Further, in the present specification, the function of transmitting near-infrared light means a function of transmitting 15% or more, preferably 50% or more, more preferably 60% or more of light having a wavelength of 750 nm or more and 1500 nm or less. I assume.

Also, “dark color” in the present specification means “color” in which the range of L ^* value, a ^* value and b ^* value in color coordinates is in the following specific range, and black is naturally included in this It is. Specifically, the specific range is a range of CIE color coordinates by standard light source D65, which is measured in accordance with JIS Z 8722, in a range of −1 ≦ a ^* ≦ 2.5 and −2 ≦ b ^* ≦ 0.5. It shall be said that the color is in this range.

  Due to the fact that the dark colored adhesive layer 12 of the infrared reflective dark color protective sheet 1 shown in FIG. 2 has a function of transmitting near infrared rays with a wavelength of 750 nm or more and 1500 nm or less, the near infrared rays are absorbed in the dark color layer. It can avoid that the temperature of the solar cell module 10 rises excessively. In addition, since the white resin base layer 11 has a function of reflecting near infrared rays, among the incident light, the near infrared rays having a wavelength of 750 nm or more and 1500 nm or less which are transmitted through the dark easy adhesion layer 12 And can be directed to the surface of the solar cell element 4 again.

  The thickness of the infrared reflective dark color protective sheet 1 is not particularly limited. However, the thickness of the white resin base layer 11 constituting the main part is preferably 35 μm or more and 350 μm or less, and more preferably 50 μm or more and 300 μm or less. Also, the thickness of the easy-to-adhere layer 12 may be suitably adjusted according to, for example, the required adhesive strength, the desired optical properties, and the designability (color tone of blackness), etc. A range of 15.0 μm or less is preferable.

  The correction method of the present invention specifies the defective portion 13 of the dark-colored easy-adhesion layer 12 generated due to a defect such as a fish eye or the like generated in the film forming process of the resin film constituting the white resin base material layer 11 described above. This is a method of correcting using a water-based dark color correction ink. According to this correction method, it is a method of recovering the excellent design having a dark appearance and the optical characteristics reflected without absorbing near infrared rays to the original levels.

[White resin base material layer]
The white resin base material layer 11 can be comprised by the white resin sheet which shape | molded the resin composition containing a white pigment in the sheet form. If necessary, additives such as an ultraviolet light absorber, a light stabilizer, an antioxidant, an antistatic agent, and a flame retardant may be further added to the resin composition.

  The white resin sheet which comprises the white resin base material layer 11 shape | molds said resin composition in a sheet form by well-known various molding methods, such as an extrusion method, T-die method, a cast molding method, an inflation method, etc. Can be obtained. Moreover, these resin sheets can be obtained by drawing the above-mentioned resin composition in a uniaxial or biaxial direction by a tenter method or a tubular method or the like, for example, a biaxially drawn resin sheet Polyethylene terephthalate or the like may be used. In addition, in this specification, although the term "resin sheet" is used as a general term of what processed the above resin compositions to a sheet form, this term is used as a concept also including a resin film. These resin sheets may have a single-layer structure, or may be a laminate composed of a plurality of layers laminated with a conventionally known adhesive or the like.

(Base resin)
Specifically, the base resin of the resin composition for forming the white resin base material layer 11 is polyethylene terephthalate (PET), preferably hydrolyzed polyethylene tephrate (HR-PET) excellent in heat resistance and hydrolysis resistance. ) Or a polyester resin such as polyethylene naphthalate (PEN). In addition, in the infrared reflective dark color protective sheet 1, even if the white resin base material layer 11 is formed using the above-described polyester resin as a base resin, the dark color easy-adhesive layer 12 is formed on the surface of the same layer. Thus, good adhesion with a sealing material for a solar cell module made of an olefin resin is secured.

(White pigment)
The resin composition forming the white resin base layer 11 contains a white pigment. As this white pigment, titanium oxide, calcium carbonate, barium sulfate, silicon dioxide and the like can be used. Among these, titanium oxide, particularly titanium oxide, which is a general-purpose product having a particle size of about 0.2 μm to 0.5 μm, can be preferably used. Thereby, the white resin base material layer 11 can be sufficiently provided with a “function of efficiently reflecting near infrared rays”. In addition, titanium oxide having a particle diameter of 0.8 μm or more and 1.2 μm or less can also be used, and according to this, the white resin base layer 11 can be provided with “a function to reflect near infrared rays extremely efficiently”. .

  Here, for the particle size of the white pigment, the primary particle size of the white pigment is photographed on a photograph using a transmission electron microscope (JEM-1230) manufactured by Nippon Denshi Co., Ltd. A value obtained by performing statistical processing with particle size distribution measurement software (MAC-View Ver. 3) is adopted. In calculating the particle diameter, a volume-based equivalent circle diameter is adopted. The particle diameters of various resin and inorganic filler powder materials in this specification are the particle diameters measured by the above method.

  What is necessary is just to adjust suitably the addition amount of said white pigment to the white resin base material layer 11 according to the thickness of the white resin base material layer 11. FIG. For example, when the thickness of the white resin base material layer 11 is in the range of 50 μm or more and 200 μm or less, the content of the white pigment added to the resin composition forming the white resin base layer 11 is 5 mass relative to the resin component of the same layer. % Or more and 40% by mass or less is preferable. If the content is less than the above ratio, "the function of reflecting near infrared radiation" tends to be insufficient, and if the content exceeds the above ratio, white resin due to film forming property reduction, bleed out, etc. While the decrease in the smoothness of the base material layer 11 becomes a problem, the effect of improving the reflectance due to the addition thereof is not recognized.

[Dark color adhesive layer]
The dark easy adhesion layer 12 is formed by applying an organic dark primer coating liquid or an aqueous dark primer coating liquid to one surface of the white resin base material layer 11 and solidifying a coating film formed from the applied dark primer coating liquid. Can be formed.

(Formation with organic dark primer coating solution)
First, a case where a dark color easy-adhesion layer is formed using an organic dark primer coating solution will be described. As an organic dark primer coating solution, it contains a crosslinkable main component resin, a polyisocyanate compound, an organometallic coordination compound, an organic dark pigment, and a silane coupling agent having a specific functional group. A coating solution can be preferably used. The organic dark primer coating solution is preferably a two-component type in which a main agent (crosslinkable main agent resin) and a curing agent (polyisocyanate compound) are mixed immediately before use.

  As main ingredient resin of organic type dark color primer coating liquid, crosslinkable substituent-containing acrylic resin or polyol compound, crosslinkable substituent-containing urethane resin, crosslinkable substituent-containing fluororesin, crosslinkable substituent-containing vinyl resin, crosslinking A functional substituent-containing olefin resin or the like can be used.

  Examples of the polyisocyanate compound used as the curing agent include aliphatic, alicyclic, aromatic, and aromatic-aliphatic compounds. The above-mentioned crosslinkable main component resin is crosslinked with these polyisocyanate compounds and cured (high molecular weight), whereby the dark color easy-adhesion layer 12 is formed. At this time, the polyisocyanate compound becomes a part of the crosslinked resin contained in the easily dark-colored adhesive layer 12 together with the main agent resin. The term "polyisocyanate compound" refers to a compound having two or more isocyanate groups in one molecule.

  The organometallic coordination compound is also called a chelating agent and contributes to curing as a crosslinking agent. In addition, the blocking resistance of the easily dark-colored adhesive layer 12 can also be improved. Moreover, adhesive strength improves remarkably by using together with the silane coupling agent which has a specific functional group mentioned later.

  As the organic dark pigment to be contained in the dark easy adhesion layer 12, various known organic pigments having infrared transparency can be appropriately used. However, a pigment comprising a mixture of a brown pigment and a phthalocyanine pigment (hereinafter, this mixed pigment is also referred to as a "benzimidazolone phthalocyanine pigment"), which will be described in detail below, is particularly preferably used. be able to. This “benzimidazolone phthalocyanine pigment” can provide the infrared reflective dark color protective sheet 1 with an excellent dark appearance and high infrared transparency.

  Among the pigment components contained in the above-mentioned “pigment consisting of a mixture of a brown pigment and a phthalocyanine pigment (benzimidazolone phthalocyanine pigment)”, the “brown pigment” may be a benzimidazolone pigment, 4 -[(2,5-dichlorophenyl) azo] -3-hydroxy-N- (2,5-dimethoxyphenyl) -2-naphthalenecarboxamide, 1-[(4-nitrophenyl) azo] -2-naphthalenol, bis [ 3-hydroxy-4- (phenylazo) -2-naphthalenecarboxylic acid] copper salt, N, N′-bis (2,4-dinitrophenyl) -3,3′-dimethoxy-1,1′-biphenyl-4, 4′-diamine, 3,4,9,10-perylenetetracarboxylic acid diimide, Δ2,2 ′ (1H, 1′H) -binaphtho [2,1-b] thiophene-1 1′-dione and N, N ′-(10,15,16,17-tetrahydro-5,10,15,17-tetraoxo-5H-dinaphtho [2,3-a: 2′3′-i] carbazole- At least one or more pigments selected from the group consisting of 4,9-diyl) bis (benzamide) can be used.

  Among the above, as the "brown pigment" used for the "pigment comprising a mixture of a brown pigment and a phthalocyanine pigment (benzimidazolone phthalocyanine pigment)", the dispersibility and adhesion of the pigment in the dark primer coating solution are improved. From the viewpoint of maximizing the effect, the “benzimidazolone-based pigment” can be particularly preferably used. The benzimidazolone pigment is a pigment having a benzimidazolone skeleton represented by the following general formula (1). Specifically, C.I. I. Pigment Yellow 120, C.I. I. Pigment Yellow 151, C.I. I. Pigment Yellow 154, C.I. I. Pigment Yellow 175, C.I. I. Pigment Yellow 180, C.I. I. Pigment Yellow 181, C.I. I. Pigment Yellow 194, C.I. I. Pigment Red 175, C.I. I. Pigment Red 176, C.I. I. Pigment Red 185, C.I. I. Pigment Red 208, C.I. I. Pigment Violet 32, C.I. I. Pigment Orange 36, C.I. I. Pigment Orange 62, C.I. I. Pigment Orange 72, C.I. I. Pigment Brown 25 etc., but not limited thereto. From the viewpoint of color gamut I. Pigment Brown 25 is more preferred.

  Among the pigment components contained in the above-mentioned “pigment consisting of a mixture of a brown-based pigment and a phthalocyanine-based pigment (benzimidazolone phthalocyanine pigment)”, the “phthalocyanine-based pigment” is a pigment having a phthalocyanine skeleton The concept also includes phthalocyanine coordinated with various metals. Specifically, C.I. I. PigmentGreen 7, C.I. I. PigmentGreen 36, C.I. I. Pigment Green 37, C.I. I. PigmentBlue 16, C.I. I. Pigment Blue 75 or C.I. I. Pigment Blue 15 or the like.

  When “a pigment consisting of a mixture of a brown-based pigment and a phthalocyanine-based pigment (benzimidazolone phthalocyanine pigment)” is used as the dark-colored primer coating solution for forming the dark-colored easy-adhesion layer 12, the “brown-based pigment” in the same pigment The content ratio is 43 parts by mass or more and 233 parts by mass or less with respect to 100 parts by mass of the phthalocyanine based pigment (the content ratio of the brown based pigment to the phthalocyanine based pigment is in the range of 30:70 to 70:30 by mass ratio) It is preferable to set it as 66 parts by mass or more and 150 parts by mass or less (the content ratio of the brown pigment to the phthalocyanine pigment is in the range of 40:60 to 60:40 by mass ratio). By setting the content ratio of both pigments in such a range, the dark color design of the infrared reflective dark color protective sheet 1 and the infrared transmittance can be made compatible at a higher level. Incidentally, the above-mentioned "pigment comprising a mixture of a brown pigment and a phthalocyanine pigment (benzimidazolone phthalocyanine pigment)" is particularly excellent in near infrared rays, in particular, infrared ray transmittance at a wavelength of 800 nm to 900 nm. It is as having been demonstrated also in the above-mentioned patent document 2, for example that it has an optical property.

  A silane coupling agent having an isocyanate group is used as the silane coupling agent to be added to the dark primer coating solution for forming the dark easy adhesion layer 12. Specific examples of this silane coupling agent include isocyanate-based silane coupling agents such as 3-isocyanatopropyltriethoxysilane. In addition, the silane coupling agent which has an isocyanate group is not specifically limited, A well-known isocyanate type silane coupling agent can be used suitably. As this silane coupling agent, for example, “KBE-9007N” (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like can be easily obtained from the market.

  The solvent used in the organic dark primer coating solution is added to impart coatability to the white resin substrate layer 11 to each component of the dark easy adhesion layer composition. The solvent is not particularly limited as long as it can dissolve or disperse components such as a crosslinkable main agent resin and a polyisocyanate compound, and does not react with the polyisocyanate compound contained in the coating liquid. Examples of such solvents include water-insoluble solvents such as toluene, xylene, butyl acetate, ethyl acetate and the like. A solvent is suitably selected according to the resin component used for a coating liquid, and is usually used in combination of 2 or more type. In addition, a high boiling point solvent such as tripropylene glycol dimethyl ether may be added to adjust the drying speed during coating.

(Formation with aqueous dark primer coating solution)
The dark easy-adhesion layer 12 is a dark primer coating solution (referred to herein as an “aqueous dark primer coating solution”) containing an aqueous medium as a main solvent, which will be described in detail below. It can also be formed by solidifying a film made of the applied coating liquid.

  Here, in the preparation of the aqueous dark primer coating solution, the acid-modified polyolefin resin is usually added to the aqueous solvent as a powder material purified to an arbitrary particle size. The average particle size of the finely powdered acid-modified polyolefin added to the aqueous dark primer coating solution, which is this aqueous dispersion, is 1.0 to 2.5 times the average particle size of the organic dark pigment in the aqueous dispersion. Not more than twice, preferably not less than 1.1 times and not more than 2.2 times. The above “average particle size” means the average value of the primary particle size when each purified powder material is added to the aqueous solvent. For example, in the case of using “a pigment consisting of a mixture of a brown pigment and a phthalocyanine pigment (benzimidazolone phthalocyanine pigment)” as the organic dark color pigment, the average particle diameter of the pigment is 0.05 μm to 0.20 μm. It is an extent. Therefore, in this case, the average particle diameter of the acid-modified polyolefin resin in the aqueous dark primer coating solution, which is the aqueous dispersion, may be about 0.05 μm to 0.50 μm and about 0.06 μm to 0.44 μm. Is more preferred. Thus, the blocking resistance of the dark easy-adhesion layer 12 can be remarkably improved by optimizing the particle size ratio.

  The average particle diameter of the acid-modified polyolefin resin is preferably 0.5 μm or less, more preferably 0.06 μm or more and 0.44 μm or less from the viewpoint of adhesiveness and dispersion stability. In addition, about the particle size of the powder material which consists of acid-modified polyolefin resin, in the case of the synthesis | combination from a raw material monomer, refinement | purification to an arbitrary particle size is possible by adjusting superposition | polymerization conditions suitably. The particle size of the acid-modified polyolefin resin and the particle size of the organic dark color pigment can be calculated by the same apparatus and method as the measurement of the particle size of the white pigment described above.

  The pH of the aqueous dispersion containing the acid-modified polyolefin resin is preferably in the range of pH 7 to 12, more preferably in the range of pH 8 to 11, from the viewpoint of dispersion stability.

  More specifically, as the acid-modified polyolefin resin, ethylene-acrylic acid ester-maleic anhydride terpolymer, or ethylene-methacrylic acid ester-maleic anhydride terpolymer, or a mixed resin thereof It can be used preferably. In addition, ethylene- (meth) acrylic acid ester-(anhydride) maleic acid copolymer such as ethylene-butyl acrylate-(anhydride) maleic acid copolymer, ethylene-propylene-(meth) acrylic acid ester-(anhydride) Maleic acid copolymer, ethylene-butene- (meth) acrylic acid ester- (anhydride) maleic acid copolymer, propylene-butene- (meth) acrylic acid ester- (anhydride) maleic acid copolymer, ethylene-propylene- Butene-(meth) acrylic acid ester-(anhydride) maleic acid copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-maleic anhydride copolymer, ethylene-propylene-(anhydride) Maleic acid copolymer, ethylene-butene- (anhydride) maleic acid copolymer, propylene-butene- (anhydride) Maleic acid copolymer, ethylene - propylene - butene - can be used (anhydrous) maleic acid copolymers.

  The above-described acid-modified polyolefin resin can be processed into an aqueous dispersion by dispersing in an aqueous medium. As a method of dispersion, a known dispersion method such as a self emulsification method or a forced emulsification method may be adopted. As an aqueous dispersion containing an acid-modified polyolefin resin, an anionic aqueous dispersion obtained by neutralizing the unsaturated carboxylic acid component of the acid-modified polyolefin resin with an basic compound in an aqueous medium, It is preferable from the viewpoint of adhesiveness.

  As the organic dark pigment to be contained in the aqueous dark primer coating solution, various organic pigments described above can be used as in the case of the organic dark primer coating solution.

  Here, the average particle diameter of "a pigment (benzimidazolone phthalocyanine pigment) composed of a mixture of a brown pigment and a phthalocyanine pigment" is about 0.05 μm to 0.20 μm. The present invention is not limited to this, and if the organic dark pigment to be contained in the easily dark adhesive layer 12 is determined, the average particle size of the acid-modified polyolefin resin in the aqueous dark primer coating liquid is the above method. By optimizing, it is possible to prepare an aqueous dark primer coating solution that can form the dark easy-adhesion layer 12 of the present invention.

  The content of the organic dark pigment in the dark aqueous primer coating solution is 0.03 to 0.50 as the solid content ratio (P / V ratio) other than the pigment / pigment in the easily adhesive layer composition. Preferably, it is 0.15-0.40. If the solid content ratio (P / V ratio) is less than 0.03, it is difficult to stably develop a uniform dark color even if the dispersion of the pigment is sufficiently increased. On the other hand, if the solid content ratio (P / V ratio) exceeds 0.35, the effect of improving the adhesion of the dark easy-adhesion layer 12 may be impaired, and the coating film itself forming the dark easy-adhesion layer 12 Since the tendency to become brittle becomes strong, it is not preferable.

  The aqueous dark primer coating liquid preferably contains a wax material as an additive for improving the blocking resistance of the dark easy-adhesion layer 12. This wax material is preferably paraffin wax. By incorporating paraffin wax in an appropriate amount range in the dark easy-adhesion layer 12, the blocking resistance can be sufficiently improved while maintaining good adhesion while being formed using an aqueous primer coating solution. The effect of the present invention can be further improved to a preferable level. In addition, paraffin wax refers to all waxes having as a main component a linear paraffin hydrocarbon having 20 to 30 carbon atoms among organic waxes which are solid at normal temperature and become liquid when heated. And “Paraffin wax aqueous dispersion (Nippon Seiki Co., Ltd., EMUSTAR-0135)” can be mentioned as a specific example of the wax material which can be preferably used.

  In addition, as a non-volatile dispersion aid for promoting the aqueous dispersion of the acid-modified polyolefin resin, for example, an emulsifier, a compound having a protective colloid action, an acid-modified compound having a high acid value, and the like in the aqueous dark primer coating solution A water-soluble polymer or the like can be added as appropriate. In addition to the non-volatile dispersion aid, various additives and other additive resins that can further improve the physical properties by adding to the easy-adhesion layer composition, more specifically, In addition to the non-volatile dispersion aid disclosed in the above-mentioned patent document (Japanese Patent Laid-Open No. 2014-240174), various additives can be preferably used as appropriate.

  An aqueous medium used as a solvent in aqueous dispersion of the acid-modified polyolefin resin or the like in the aqueous dark primer coating solution used to form the easy-to-adhere layer 12 is a medium consisting of water or a liquid containing water. In the aqueous dark primer coating solution, an organic solvent having an SP value in a specific range as an auxiliary solvent is further added as an auxiliary solvent in an aqueous dispersion containing an acid-modified polyolefin resin within a range not inhibiting the expression of the above-mentioned effects of the present invention. Can be included. Specifically, when the solvent of the easy adhesion layer composition contains an organic solvent as an auxiliary solvent, the content of the organic solvent with respect to 100 parts by mass of the solvent is 1 part by mass or more and less than 50 parts by mass, Preferably, it is 1 part by mass or more and less than 30 parts by mass.

[Production method of infrared reflective dark protection sheet]
The infrared reflective dark color protective sheet 1 is formed by applying the above-mentioned organic dark primer coating liquid or aqueous dark primer coating liquid to the surface of the white resin base layer 11 to form a coating film. Can be produced.

  As a method of apply | coating a dark primer coating liquid to the surface of the white resin base material layer 11 of the infrared reflective dark protection sheet 1, the conventionally well-known method can be used without a restriction | limiting especially. Examples of such a coating method include a printing method, a coating method using a gravure coater, a roll coating method, a spray coating method, a dip coating method, a solid coating method, and a brush coating method.

The application amount of the dark primer coating solution may be appropriately adjusted so that the thickness of the easy-to-adhere layer 12 falls within the above range as the application amount after drying, but 0.01 g / m as the application amount after drying. ² or more and 100 g / m ² or less are preferable, and 0.1 g / m ² or more and 50 g / m ² or less are more preferable. If the film is formed so that the coating amount is in the range of 0.01 to 100 g / m ² , a coating film having excellent uniformity can be obtained.

  At this time, when the dark primer coating liquid is cured, if the above-mentioned defects 13 are generated in the easy-to-adhere layer 12, the correction method of the infrared reflective dark protective sheet of the present invention is used to promptly It can be corrected. For example, even in the case of producing an infrared dark protective sheet on a roll-to-roll production line, since the correction can be completed online in the minimum time, the product with a defect is discarded Production can be continued without any problems.

<How to modify the infrared reflective dark protection sheet>
First, as a method for correcting the defect portion 13 of the dark color easy-adhesive layer 12 that is inevitably generated in the manufacturing stage of the infrared reflective dark color protective sheet 1, the defect portion 13 on the surface of the dark easy-adhesion layer 12 is viewed in plan view. It is conceivable to apply black correction ink to a horizontal position where the ink is concealed. However, for example, when this is performed with a general black ink containing a general-purpose pigment such as carbon ink, since the carbon black also absorbs infrared rays, the correction portion 121 is formed by this. In this case, the infrared transparency of the dark easy-adhesion layer 12 is hindered at this portion, so that it does not function at all. Also, in terms of design, the dark easy-adhesion layer 12 usually has a darker color that is slightly closer to any one than the black color of carbon black. As a result, the original design can not be sufficiently restored even by correction.

  In addition, in the correction of the easy-to-adhere dark layer 12 which is an extremely thin layer that is required to have both adhesiveness and blocking resistance compatible, for example, in the case of using an organic correction ink generally used conventionally There is a risk of damage by the organic solvent to the surface of the easy-to-adhere layer 12 or the surface of the white resin base layer 11 immediately below the defect, and these are usually of the two-component type. Needs to be heat-treated to make it react, and it is not possible to sufficiently meet such requirements, especially when it is strictly required to shorten the time required for correction in a roll-to-roll production line. was there.

  Therefore, in the correction method of the present invention, the use of carbon black, which is a general black ink, and the use of organic correction ink are excluded, and the ink used for correction of a defective portion is the dark easy adhesion layer 12. It was identified as a one-part aqueous dark correction ink comprising an organic dark pigment similar to that included. Then, the one-component aqueous dark color correction ink was applied in such a manner that the surface of the dark easy adhesion layer 12 was covered with the defect portion 13.

  The method for applying the aqueous dark color correction ink is not particularly limited, but it is preferable that the one-component type can be used to achieve the merit of being able to rapidly apply only the necessary part at a point. For example, application with a cotton swab, a needle or the like, or application with a spray or the like can be mentioned as a preferred example. The correction portion 121 formed in this manner can restore the design of the infrared reflective dark protective sheet 1 without inhibiting the infrared ray transmitting property of the easily dark layer 12 in the defective portion 13.

  The aqueous dark color correction ink used in the correction method of the present invention is a one-component aqueous dispersion containing an olefin resin and an organic dark color pigment as main components and an aqueous medium as a solvent. This aqueous dark color correction ink has the advantage of being able to be corrected more quickly since the curing time is shorter than the organic type correction ink which is usually a two-component type.

  Further, this aqueous dark correction ink is identical to the olefin resin, the organic dark pigment, and the solvent as the olefin resin, the organic dark pigment and the solvent used in the above-mentioned aqueous dark primer coating liquid, respectively. The thing can be used. Therefore, the correction method of the present invention can achieve particularly advantageous effects when the easy-to-adhere layer 12 of the infrared reflective dark protective sheet 1 is formed of an aqueous dark primer coating solution. In this case, the color of the correction portion 121 and the dark easy adhesion layer 12 can be more easily unified more strictly, and the cost reduction can be expected because the main material of the correction ink becomes the same amount of material as the product. It will be.

  According to the correction method of the infrared reflective dark protection sheet of the present invention described above and the manufacturing method of the infrared reflective dark protection sheet, the following effects can be obtained.

  (1) The correction ink used to correct the infrared reflective dark protective sheet 1 having the easy-to-adhere dark layer 12 is an aqueous dark correction ink prepared by blending the organic dark pigment contained in the easy-to-adhere layer 12 . This avoids the risk of secondary damage in a very short time, and the correction of the defective portion 13 including the restoration of the deterioration of the designability due to the fine defects of the resin layer and the recovery of the infrared ray transmission function in the correction portion 121. Can be done safely.

  (2) The organic dark pigment to be contained in the aqueous dark correction ink is made of a predetermined organic pigment or a combination thereof. Thereby, the correction method described in (1) can be suitably applied to various types of infrared reflective dark protective sheets 1.

  (3) The olefin resin constituting the aqueous dark color correction ink was an alkene having 2 to 6 carbon atoms, which is an unsaturated carboxylic acid or its anhydride. Thereby, the adhesiveness and blocking resistance of the correction part 121 formed with the aqueous dark color correction ink can be maintained at a stable and excellent level.

  (4) The solvent of the aqueous dark correction ink was supplemented with an appropriate range of the organic solvent. By substituting an organic solvent in an appropriate amount range, the time required for coating film formation is maintained while maintaining the effect of the correction method according to any one of (1) to (3). Further shortening is possible. In addition, the inclusion of the organic solvent has an advantage that the solid content ratio changes and the fine adjustment of the color tone becomes easy.

  (5) When the base resin of the white resin base layer 11 is a polyester resin, in order to secure good adhesion to the olefin resin base, normally, formation of the easy adhesion layer is essential. . In this case, the correction method of (1) to (4) is a correction method of the infrared reflective dark protective sheet 1 in which the dark easy adhesion layer 12 is formed as an essential layer on the surface of the white resin base layer 11. Especially useful.

  (6) According to the method for producing an infrared reflective dark color protective sheet of the present invention, comprising the step of correcting the defect 13 by the correction method according to any one of (1) to (5), the material resin It is possible to significantly improve the productivity of the infrared reflective dark protective sheet 1 while avoiding the decrease in the yield of the non-defective product due to the minute defects in the resin layer, which inevitably occurs at the film forming stage of the sheet.

  (7) The production method of the infrared reflective dark protective sheet of the present invention, which is capable of correcting the defective portion in a very short time, includes a roll-to-roll method, and a production line including a winding process of the material sheet. In particular, it is useful for maintaining its high productivity.

  As mentioned above, according to the correction method of the infrared reflective dark protection sheet of this invention, and the manufacturing method of an infrared reflective dark protection sheet, the infrared reflective dark which can be used for the back surface protection sheet for solar cell modules, for example It can be seen that the provision of a method for correcting a defect which inevitably occurs in the resin layer at the manufacturing stage in the protective sheet can contribute to the improvement of the quality and productivity of the infrared reflective dark protective sheet.

DESCRIPTION OF SYMBOLS 1 Infrared reflective dark protection sheet 11 White resin base layer 12 Dark easy adhesion layer 121 Correction part 13 Defective part 2 Transparent front substrate 3, 5 Sealing material 4 Solar cell element 10 Solar cell module

Claims (7)

A method for correcting an infrared reflective dark color protective sheet in which a dark easy adhesion layer containing an organic dark pigment that transmits near infrared rays having a wavelength of 750 nm to 1500 nm is formed on one surface of a white resin base material layer. ,
In a mode of covering a defect portion generated in the dark easy-adhesion layer, the method comprises a step of applying an aqueous dark color correction ink,
The aqueous dark correction ink is a one-component aqueous dispersion containing an olefin resin and the organic dark pigment as main components and an aqueous medium as a solvent. The organic dark pigment comprises a brown pigment and a phthalocyanine pigment,
The brown pigment is benzimidazolone pigment, 4-[(2,5-dichlorophenyl) azo] -3-hydroxy-N- (2,5-dimethoxyphenyl) -2-naphthalenecarboxamide, 1-[(4 -Nitrophenyl) azo] -2-naphthalenol, bis [3-hydroxy-4- (phenylazo) -2-naphthalenecarboxylic acid] copper salt, C.I. I. Pigment Brown 7, N, N′-bis (2,4-dinitrophenyl) -3,3′-dimethoxy-1,1′-biphenyl-4,4′-diamine, 3,4,9,10-perylenetetracarboxylic acid Diimide, Δ2,2 ′ (1H, 1′H) -binaphtho [2,1-b] thiophene-1,1′-dione and N, N ′-(10,15,16,17-tetrahydro-5,10 , 15,17-tetraoxo)-(5H-dinaphtho [2,3-a: 2′3′-i] carbazole-4,9-diyl) bis (benzamide) The correction method according to claim 1, wherein   The correction method according to claim 1 or 2, wherein the olefin-based resin is an unsaturated carboxylic acid or an anhydride thereof and an alkene having 2 to 6 carbon atoms.   The correction method according to any one of claims 1 to 3, wherein the solvent contains an organic solvent as an auxiliary solvent in a content range of less than 50 parts by mass per 100 parts by mass of the solvent.   The correction method of the infrared reflective dark color protection sheet in any one of Claim 1 to 4 whose base resin of the said white resin base material layer is a polyester-type resin.   The manufacturing method of the infrared reflective dark color protection sheet which comprises the process of correcting the said defect | deletion part by the correction method in any one of Claim 1 to 5.   The manufacturing method of the infrared reflective dark color protection sheet for solar cell modules of Claim 6 including the winding-up process of the material sheet by a roll-to-roll system.

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