JP2013052635A - Laminate sheet and solar cell obtained by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a polycarbonate-based sheet excellent in high wet heat resistance over a long period of time; and a solar cell, the durability of which is made higher since the solar cell is obtained by using the polycarbonate-based sheet.SOLUTION: A laminate sheet has a layer (P1 layer), which includes a polycarbonate resin as a main constituent component, and another layer (P2 layer) which includes a polybutylene terephthalate resin as the main constituent component and contains inorganic particles of 2-20 mass% content ratio Wa2. The laminate sheet satisfies inequality (I): (Wa2+16)/9≤T1/T2 (wherein T1 is the thickness of the P1 layer; T2 is the thickness of the P2 layer).

Description

  The present invention relates to a polycarbonate laminate sheet excellent in moisture and heat resistance, heat resistance and ultraviolet resistance. In particular, the present invention relates to a polycarbonate laminate sheet that can be suitably used as a solar cell backsheet, and also relates to a solar cell backsheet or solar cell using the film.

  In recent years, photovoltaic power generation, which is clean energy, has attracted attention as a semi-permanent and pollution-free next-generation energy source, and solar cells are rapidly spreading.

An example of the configuration of the solar cell is shown in FIG. In the solar cell, the power generating element 3 is sealed with a transparent sealing material layer 2 such as EVA (ethylene-vinyl acetate copolymer), a transparent substrate 4 such as glass, and a back sheet 1 for solar cells. A resin sheet is bonded together. Sunlight is introduced into the solar cell through the transparent substrate 4. Sunlight introduced into the solar cell is absorbed by the power generation element 3, and the absorbed light energy is converted into electrical energy. The converted electric energy is taken out by a lead wire (not shown in FIG. 1) connected to the power generation element 3 and used for various electric devices. Here, the solar cell backsheet 1 is a sheet member that is installed on the back side of the power generation element 3 with respect to the sun and is not in direct contact with the power generation element 3. Various proposals have been made for the solar cell system and each member. For the solar cell backsheet 1, polyethylene-based, polyester-based, and fluorine-based resin films are mainly used. (See Patent Documents 1 to 3)
On the other hand, polycarbonate resins are widely used for outdoor materials such as carports and signboards, optical disks, molding materials and the like because they are excellent in mechanical properties, thermal properties, heat and humidity resistance, heat resistance, transparency and moldability. However, in order to apply the polycarbonate-based resin to an application that is used outdoors for a long period of time, such as a back sheet for a solar cell, it is necessary to suppress a change in color tone and deterioration of high elongation due to ultraviolet rays.

  Therefore, various studies have been made in order to suppress the change in color tone and the deterioration of the strength and elongation of polycarbonate due to ultraviolet rays. For example, a technique of adding inorganic particles to a polycarbonate-based resin (Patent Document 4) has been studied. Moreover, in order to improve the ultraviolet resistance of the polycarbonate-based resin, an acrylic resin layer containing an ultraviolet absorber is laminated on a transparent or white polycarbonate resin layer (Patent Documents 5, 6, and 7) or in close contact with a sealing material. Technology such as laminating a polybutylene terephthalate (PBT) -based resin layer (Patent Document 8) is also being studied in order to improve the properties.

JP-A-11-261085 JP-A-11-186575 JP 2006-270025 A JP 2007-191499 A JP 2006-343445 A Japanese Patent Laid-Open No. 11-58627 Japanese Patent Laid-Open No. 11-334017 JP 2009-141345 A

  However, with the conventional polycarbonate sheet, it has been difficult to provide the high UV resistance required for solar cell backsheets.

  Then, the subject of this invention provides the polycarbonate-type sheet | seat which has the heat-and-moisture resistance and heat resistance which can be applied also to a solar cell backsheet, and is excellent in ultraviolet-ray resistance (suppression of a strong elongation deterioration, suppression of a color tone change). That is.

In order to solve the above problems, the present invention has the following configuration. That is,
It has a layer (P1 layer) mainly composed of a polycarbonate-based resin and a layer (P2 layer) composed mainly of a polybutylene-based terephthalate resin and having an inorganic particle content Wa2 of 2% by mass or more and 20% by mass or less. A laminated sheet, in which the ratio T1 / T2 of the layer thickness T1 of the P1 layer and the layer thickness T2 of the P2 layer satisfies the following formula (I).
(Wa2 + 16) / 9 ≦ T1 / T2 (I)

  ADVANTAGE OF THE INVENTION According to this invention, the laminated sheet which is excellent in ultraviolet resistance compared with the conventional laminated sheet can be provided. Such a laminated sheet is suitably used for applications where importance is attached to resistance to moisture and heat, heat resistance, and ultraviolet rays, including a back sheet for a solar cell, a reflector for a liquid crystal display, an automobile material, and a building material. can do. In particular, by using such a laminated sheet, a solar cell backsheet having high durability and a solar cell using the same can be provided.

It is sectional drawing which shows typically an example of a structure of the solar cell using the lamination sheet of this invention.

It has a layer (P1 layer) mainly composed of a polycarbonate-based resin and a layer (P2 layer) composed mainly of a polybutylene terephthalate-based resin and having an inorganic particle content Wa2 of 2% by mass or more and 20% by mass or less. A laminated sheet, in which the ratio T1 / T2 of the layer thickness T1 of the P1 layer and the layer thickness T2 of the P2 layer satisfies the following formula (I).
(Wa2 + 16) / 9 ≦ T1 / T2 (I)
By satisfying the above requirements, it is possible to provide a laminated sheet having long-term moist heat resistance, heat resistance, and ultraviolet resistance applicable to uses such as a solar cell backsheet. In addition, in the P1 layer, the main constituent component here means that 60% by mass or more of the resin components constituting the layer is a polycarbonate-based resin, more preferably 70% by mass or more, and still more preferably 80% by mass. % Or more. In addition, when there are two or more layers mainly composed of polycarbonate-based resin, a concentration difference of ± 8% or less is regarded as the same layer (this value is based on the concentration of adjacent adjacent layers). (For example, when the concentration is 20% by mass, it is 18.4 to 21.6% by mass). Here, when there are two or more layers having different particle concentrations, the layer having the lowest particle concentration is defined as the P1 layer.

In the P2 layer, it indicates that 60% by mass or more of the constituent components of the layer is a polybutylene terephthalate resin, more preferably 70% by mass or more, and further preferably 80% by mass or more. Further, in the case where there are two or more layers containing polybutylene terephthalate resin as a main constituent component, a concentration difference of ± 8% or less is regarded as the same layer. Here, in the case where there are two or more layers having different particle concentrations, the layer having the highest particle concentration is defined as the P2 layer with respect to the layer mainly composed of polybutylene terephthalate resin.
Furthermore, the laminated sheet of the present invention is, for example, as described later, (i) a two-layer structure composed of P1 layer / P2 layer, and (ii) a multilayer composed of P1 layer / P2 layer /. Preferred examples include a laminated structure, (iii) P1 layer / P2 layer / other layer, (iv) other layer / P1 layer / P2 layer, P1 layer / other layer / P2 layer, etc. Of the P1 layer and P2 layer constituting the laminated sheet, the first layer from one surface side is the P1 layer, and the first layer from the other surface side is the P2 layer (hereinafter these configurations are asymmetrical). In the case where the other layers may be composed of a plurality of layers, a laminated sheet having excellent curl resistance can be obtained. The reason will be described in detail below.

  Usually, in order to enhance the functionality of polycarbonate resin, inorganic particles are added to the polycarbonate resin. In that case, once the masterbatch containing particles at a high concentration is prepared, a method of diluting is used. It is done. However, since a heat history is received during the production of the masterbatch, the polycarbonate resin deteriorates. Moreover, since the inorganic particles originally have adsorbed water, the hydrolysis reaction of the polycarbonate resin containing the inorganic particles is promoted. As a result of the combination of these two phenomena, the heat-and-moisture resistance decreases. In addition, the polycarbonate-based resin was originally easily yellowed with respect to ultraviolet rays, and could not be completely suppressed even when particles were added and whitened.

On the other hand, in the laminated sheet of the present invention, a polybutylene terephthalate-based resin is a main constituent component in the P2 layer, and by laminating a layer (P2 layer) having an inorganic particle content Wa2 of 2 mass% or more and 20 mass% or less, It is possible to impart characteristics (for example, light reflectivity, whiteness) according to the type of inorganic particles to the laminated sheet. On the other hand, by laminating the polybutylene terephthalate-based resin layer containing inorganic particles, the heat and moisture resistance and heat resistance of the laminated sheet tend to be reduced, but the layer thickness T1 of the P1 layer and the layer thickness T2 of the P2 layer When the ratio T1 / T2 satisfies the following formula (I), it becomes possible to impart wet heat resistance and heat resistance applicable to a solar cell backsheet or the like.
(Wa2 + 16) / 9 ≦ T1 / T2 (I)
Hereinafter, the present invention will be described in detail with specific examples.
The polycarbonate-based resin which is the main component of the P1 layer of the laminated sheet of the present invention is a polymer obtained by reacting a dihydroxydiaryl compound with a carbonate such as phosgene or diphenyl carbonate.
Examples of the dihydroxydiaryl compound used in the polycarbonate resin in the P1 layer of the laminated sheet of the present invention include 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A), bis (4-hydroxyphenyl) methane. 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxyphenyl-3-methylphenyl) propane, 1,1-bis (4-hydroxy-3-tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromo) Phenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, , 2-bis (4-hydroxy-3,5-dichlorophenyl) propane, bis (hydroxyaryl) alkane compounds, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxy) Bis (hydroxyaryl) cycloalkane compounds such as phenyl) cyclohexane, 4,4′-dihydroxydiphenyl ether, dihydroxydiaryl ether compounds such as 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether, 4,4 ′ Dihydroxy diaryl sulfide compounds such as dihydroxydiphenyl sulfide, 4,4′-dihydroxydiphenyl sulfoxide, dihydroxy diaryl sulfoxide compounds such as 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfoxide, 4,4′-di Examples thereof include, but are not limited to, dihydroxydiarylsulfone compounds such as hydroxydiphenylsulfone and 4,4′-dihydroxy-3,3′-dimethyldiphenylsulfone. Moreover, these may be used independently or may be used in multiple types as needed.
Moreover, in addition to the above-mentioned dihydroxy diaryl compound, you may use the compound which has 3 or more of phenolic hydroxyl groups for the polycarbonate-type resin of P1 layer of the lamination sheet of this invention. Examples include phloroglucin, 4,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) -heptene, 2,4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl)- Heptane, 1,3,5-tri- (4-hydroxyphenyl) -benzol, 1,1,1-tri- (4-hydroxyphenyl) -ethane and 2,2-bis [4,4- (4,4 And '-dihydroxydiphenyl) -cyclohexyl] -propane.

  Here, in the laminated sheet of the present invention, the polycarbonate resin, which is the main component of the P1 layer, is a polycarbonate whose main component is 2,2-bis (4-hydroxyphenyl) propane (commonly referred to as bisphenol A) as a dihydroxydiaryl compound. It is preferable to use a resin based on heat resistance and heat and humidity resistance. The main component referred to here is 80 mol% or more, more preferably 90 mol% or more, and still more preferably 95 mol% or more, of all dihydroxydiaryl compounds used in the polycarbonate resin. Furthermore, the polycarbonate-based resin that is the main component of the P1 layer is a polycarbonate-based resin in which 2,2-bis (4-hydroxyphenyl) propane (commonly referred to as bisphenol A) is the main component as the dihydroxydiaryl compound. Is more preferable in that heat resistance and wet heat resistance can be further improved.

In the laminated sheet of the present invention, the number average molecular weight (Mn) of the polycarbonate-based resin is preferably 10,000 or more and 50,000 or less. More preferably, it is 12000 or more and 40000 or less, More preferably, it is 15000 or more and 30000 or less.
In the laminated sheet of the present invention, the higher the glass transition temperature Tg of the polycarbonate resin, the higher the moisture and heat resistance, and the step of sealing the power generation cell together with the sealing material when used as a solar cell backsheet. From the viewpoint of form retention in the sealing step of the laminated sheet.

  Tg is measured in accordance with JIS K7122 (1987) by heating the resin from 25 ° C. to 300 ° C. at a rate of temperature increase of 20 ° C./min (1st RUN) for 5 minutes. Hold. Next, in the 2ndRUN differential scanning calorimetry chart obtained by rapidly cooling to 25 ° C. or less and then increasing the temperature from room temperature to 300 ° C. at a rate of temperature increase of 20 ° C./min. In JIS K7121 (1987), the method described in “9.3 Determination of Glass Transition Temperature (1) Intermediate Glass Transition Temperature Tmg” is used.

The glass transition temperature Tg is preferably 125 ° C. or higher, more preferably 130 ° C. or higher, still more preferably 135 ° C. or higher, and particularly preferably 140 ° C. or higher.
The polybutylene terephthalate resin, which is the main component of the P2 layer of the laminated sheet of the present invention, is a polyester having butylene terephthalate as a main repeating unit composed of terephthalate as a dicarboxylic acid component and 1,4-butanediol as a diol component. Refers to resin. The main repeating unit as used herein means that the total of the above repeating units is 80 mol% or more, more preferably 90 mol% or more, and still more preferably 95 mol% or more of all repeating units.
In such a polybutylene terephthalate resin, other components may be copolymerized in addition to terephthalic acid as a dicarboxylic acid component and 1,4-butanediol as a diol component. Specifically, as the dicarboxylic acid component, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, dimer acid, eicosandioic acid, pimelic acid, azelaic acid, methylmalonic acid, ethyl Aliphatic dicarboxylic acids such as malonic acid, alicyclic dicarboxylic acids such as adamantane dicarboxylic acid, norbornene dicarboxylic acid, isosorbide, cyclohexane dicarboxylic acid, decalin dicarboxylic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1 , 5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenyletherdicarboxylic acid, 5-sodium sulfoisophthalic acid, phenylendane Dicarboxylic acid, Cement spiral dicarboxylic acid, phenanthrene carboxylic acid, 9,9'-bis (4-carboxyphenyl) fluorene acids, aromatic dicarboxylic acids such or its ester derivatives, it does not matter be copolymerized. In addition, there may be added oxyacids such as l-lactide, d-lactide, hydroxybenzoic acid, and derivatives thereof, or a combination of a plurality of oxyacids to the carboxyl group terminal of the carboxylic acid component. It is suitably used as a copolymerization component. Moreover, you may use these in multiple types as needed.

  Examples of copolymer components other than 1,4-butanediol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3 -Aliphatic diols such as butanediol, cycloaliphatic diols such as cyclohexanedimethanol, spiroglycol and isosorbide, bisphenol A, 1,3-benzenedimethanol, 1,4-benzenedimethanol, 9,9'-bis ( Examples include, but are not limited to, aromatic diols such as 4-hydroxyphenyl) fluorene, and those in which a plurality of the above diols are linked. Moreover, you may use these in multiple types as needed.

A polybutylene terephthalate-based resin can be obtained by appropriately combining the dicarboxylic acid component and the diol component described above and polycondensing them. The melting point of the resulting polybutylene terephthalate resin is generally 200 ° C. or higher and 230 ° C. or lower. Furthermore, in the present invention, it is more preferable to use one having a melting point of 215 ° C. or higher and 230 ° C. or lower.
The intrinsic viscosity (IV) of the polybutylene terephthalate resin used for the P2 layer of the laminated sheet of the present invention is preferably 0.6 or more. More preferably, it is 0.7 or more, more preferably 0.8 or more, particularly preferably 0.9 or more. If the IV is less than 0.6, the lamination property with the polycarbonate-based resin may be deteriorated, or even if it can be laminated, the molecular weight is too low and the heat-and-moisture resistance of the laminated sheet may be lowered. In the laminated sheet of the present invention, when the IV of the polybutylene terephthalate resin used for the P2 layer is 0.6 or more, good lamination properties and high heat and humidity resistance can be obtained. Although the upper limit of IV is not particularly determined, it is preferably 2.0 or less, more preferably 1.9 or less, from the viewpoint that melt extrusion becomes difficult.

The P2 layer of the laminated sheet of the present invention contains inorganic particles. The inorganic particles are used for imparting a necessary function to the laminated sheet according to the purpose. Examples of the particles that can be suitably used in the present invention include inorganic particles having ultraviolet absorbing ability, polycarbonate-based resins, particles having a large refractive index difference from polybutylene terephthalate-based resins, conductive particles, and pigments. Thus, UV resistance, optical properties such as light reflectivity and whiteness, antistatic properties and the like can be imparted. In addition, a particle means a thing with 5 nm or more as a primary particle size by the diameter of the projected equivalent conversion circle | round | yen. Unless otherwise specified, in the present invention, the particle size means a primary particle size, and the particle means a primary particle.

  The particles will be described in more detail. In the present invention, examples of inorganic particles include gold, silver, copper, platinum, palladium, rhenium, vanadium, osmium, cobalt, iron, zinc, ruthenium, praseodymium, chromium, nickel, and aluminum. Metals such as tin, zinc, titanium, tantalum, zirconium, antimony, indium, yttrium, lanthanum, zinc oxide, titanium oxide, cesium oxide, antimony oxide, tin oxide, indium tin oxide, yttrium oxide, lanthanum oxide, oxide Metal oxides such as zirconium, aluminum oxide, silicon oxide, lithium fluoride, magnesium fluoride, aluminum fluoride, metal fluorides such as cryolite, metal phosphates such as calcium phosphate, carbonates such as calcium carbonate, sulfuric acid barium Salts of sulfuric acid, talc and kaolin.

  In the present invention, in view of the fact that it is often used outdoors, in the case of using a metal oxide such as titanium oxide, zinc oxide, cerium oxide, or the like, particles having ultraviolet absorbing ability, for example, inorganic particles, The effect of the present invention of maintaining the mechanical strength over a long period by utilizing the ultraviolet resistance by the particles can be remarkably exhibited. Furthermore, titanium oxide is preferably used as the inorganic particles in that high reflection characteristics can be imparted, and rutile titanium oxide is more preferably used in terms of higher ultraviolet resistance.

  The volume average particle diameter of the inorganic particles used in the laminated sheet of the present invention is 10 nm or more and 3 μm or less, particularly preferably 15 nm or more and 2 μm or less.

In the laminated sheet of the present invention, the inorganic particle content Wa2 of the P2 layer is 2% by mass or more and 20% by mass or less. More preferably, they are 5 mass% or more and 18 mass% or less, More preferably, they are 4 mass% or more and 12 mass% or less. When the inorganic particle content Wa2 is less than 1% by mass, the effect is not sufficiently exhibited, particularly in the case of particles having ultraviolet absorbing ability, the ultraviolet resistance is insufficient, and the mechanical strength is lowered during long-term use. In addition, the laminated sheet may be easily broken. Moreover, when inorganic particle content rate Wa2 exceeds 20 mass%, the heat-and-moisture resistance of a lamination sheet may fall. Further, when the P2 layer is used as an adhesion surface, the adhesion may be lowered. In the laminated sheet of the present invention, when the inorganic particle content Wa2 of the P2 layer is 2% by mass or more and 20% by mass or less, the effect of adding particles can be expressed while maintaining the mechanical properties of the laminated sheet. Moreover, even if the P2 layer is used as an adhesion surface, good adhesion can be obtained.
In the laminated sheet of the present invention, the P1 layer preferably contains inorganic particles. By containing inorganic particles in the P1 layer, the effect of adding particles can be further enhanced. The inorganic particles referred to here are the same as the inorganic particles contained in the P2 layer described above. At this time, the inorganic particle content Wa1 of P1 is preferably 0.1% by mass or more and 15% by mass or less. More preferably, they are 1 mass% or more and 10 mass% or less, More preferably, they are 3 mass% or more and 8 mass% or less. When the inorganic particle content Wa1 of the P1 layer exceeds 15% by mass, the heat and moisture resistance may be lowered.
In the laminated sheet of the present invention, when the inorganic particles are contained in the P1 layer, the ratio Wa1 / Wa2 between the inorganic particle content Wa1 of the P1 layer and the inorganic particle content Wa2 of the P2 layer is 0 or more and 0.8 or less. It is preferable that More preferably, they are 0 or more and 0.7 or less, More preferably, they are 0 or more and 0.5 or less. When Wa1 / Wa2 exceeds 0.8, Wa1 becomes too large and the heat and humidity resistance may be lowered. In the laminated sheet of the present invention, the ratio Wa1 / Wa2 between the inorganic particle content Wa1 of the P1 layer and the inorganic particle content Wa2 of the P2 layer is 0 or more and 0.8 or less, so that the particles can be produced without a decrease in wet heat resistance. It is possible to maximize the effect of the inclusion.

In the laminated sheet of the present invention, it is preferable that the average Wave of the particle content of the P1 layer and the P2 layer is 3% by mass or more. Here, the average Wave of the particle content of the P1 layer and the P2 layer is a value obtained by the following formula (1).
Average Wave of Inorganic Particle Content Wave = (Wa1 × T1 + Wa2 × T2) / (T1 + T2) (1)
However, T1 is the layer thickness (μm) of the P1 layer, and T2 is the layer thickness (μm) of the P2 layer.
The average Wave of the particle content of the P1 layer and the P2 layer is more preferably 5% by mass or more, and further preferably 10% by mass or more. In the laminated sheet of the present invention, by setting the inorganic particle ratio Wave of the entire laminated sheet to 3% by mass or more, the effect of including inorganic particles as the whole of the P1 layer and the P2 layer, for example, ultraviolet resistance is further improved. In addition, when titanium oxide or the like is used as the inorganic particles, the light reflection characteristics of the laminated sheet can be improved.

  Further, the P1 layer and the P2 layer of the laminated sheet of the present invention have other additives (for example, a heat stabilizer, an ultraviolet absorber, a weather stabilizer, an organic lubricant, as long as the effects of the present invention are not impaired). Pigments, dyes, fillers, antistatic agents, nucleating agents, etc. However, the inorganic particles referred to in the present invention may not be implied by the additives herein. For example, when an ultraviolet absorber is selected as the additive, the ultraviolet resistance of the laminated sheet of the present invention can be further improved. For example, examples of organic ultraviolet absorbers compatible with polycarbonate resins and polybutylene terephthalate resins include salicylic acid-based, benzophenone-based, benzotriazole-based, triazine-based, cyanoacrylate-based ultraviolet absorbers and hindered amines. And ultraviolet absorbers. Specifically, for example, salicylic acid-based pt-butylphenyl salicylate, p-octylphenyl salicylate, benzophenone-based 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy -5-sulfobenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, bis (2-methoxy-4-hydroxy-5-benzoylphenyl) methane, 2- (2'-hydroxy-5) of benzotriazole series '-Methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2,2'-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H benzotriazol-2-yl) phenol], triazine-based 2- (4 -Diphenyl-1,3,5-triazin-2-yl) -5 [(hexyl) oxy] -phenol, cyanoacrylate-based ethyl-2-cyano-3,3'-diphenylacrylate), hindered amine-based bis ( 2,2,6,6-tetramethyl-4-piperidyl) sebacate, dimethyl succinate 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate It is done.

  Other examples include 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol, nickel bis (octylphenyl) sulfide, and 2,4-di T-butylphenyl-3 ′, 5′-di-t-butyl-4′-hydroxybenzoate and the like.

  The laminated sheet of the present invention has a laminated structure including a P1 layer and a P2 layer that satisfy the above-described requirements, and is configured such that the P2 layer is located on at least one surface layer side with respect to the P1 layer in the laminated sheet. That is, when the laminated structure is viewed from either one surface side of the laminated sheet, the first layer of the P1 layer and the P2 layer constituting the laminated sheet is the P2 layer. Especially, the structure whose at least one outermost layer of a lamination sheet is P2 layer is preferable. The other outermost layer is preferably a P2 layer or a P1 layer. Further, a sheet including a layer made of a polycarbonate-based resin has a sealing material and other constituent members as compared with polyethylene terephthalate (hereinafter sometimes abbreviated as “PET”) generally used for a solar cell backsheet. Therefore, even when the P1 layer is located on the other outermost layer (for example, the configuration of P1 layer / P2 layer), the adhesiveness is high. In addition, when the P1 layer is located on the other outermost layer and the P1 layer is provided on the surface that is in close contact with the sealing material or other constituent members, the laminated sheet contains moisture and heat resistance and particles. Therefore, it is possible to provide a laminated sheet having an extremely high level of property improvement effect and having higher adhesion (when bonded to another member). In addition, when the P2 layer is located on the other outermost layer (for example, the structure of P2 layer / P1 layer / P2 layer, etc.), it is possible to exhibit the effect of containing particles on both sides, and it is more resistant. A laminated sheet having a high ultraviolet property can be obtained. Of these configurations, it is more preferable that the P2 layer is located in the other outermost layer in terms of excellent ultraviolet resistance.

  The total thickness of the laminated sheet of the present invention is preferably 10 μm or more and 500 μm or less, more preferably 20 μm or more and 450 μm or less, and most preferably 30 μm or more and 400 μm or less. Moreover, when using the laminated sheet of this invention for the solar cell backsheet use, thickness is suitably adjusted within the said range according to the withstand voltage requested | required of the solar cell backsheet. When the thickness of the laminated sheet of the present invention is less than 10 μm, the flatness of the laminated sheet may be deteriorated, or the P2 layer may be too thin, and the effect of improving the characteristics due to the inclusion of particles may be reduced, from 500 μm When it is thick, for example, when used as a solar cell backsheet, the overall thickness of the solar cell may become too thick.

In the laminated sheet of the present invention, when the layer thickness of the P1 layer is T1 (μm) and the layer thickness of the P2 layer is T2 (μm), the ratio T1 / T2 of both satisfies the following formula (I).
(Wa2 + 16) / 9 ≦ T1 / T2 (I)
More preferably, T1 / T2 is 3 or more, further preferably 4 or more, and particularly preferably 5 or more. In addition, when there are a plurality of P1 layers and / or P2 layers, the total thickness is defined as the layer thickness T1 of the P1 layer and the layer thickness T2 of the P2 layer, respectively. If the ratio T1 / T2 of the layer thickness T1 of the P1 layer and the layer thickness T2 of the P2 does not satisfy the above formula (I), the moisture and heat resistance and heat resistance of the laminated sheet may be reduced, and may be easily broken during long-term use. . Further, when the laminated sheet of the present invention has an asymmetric configuration, the curl may become too large. In the laminated sheet of the present invention, by satisfying the above formula (I) for T1 / T2, it becomes possible to impart wet heat resistance and heat resistance applicable to a solar cell backsheet or the like. The upper limit of T1 / T2 is not particularly defined. For example, when film formation is performed by a coextrusion method, film formation is good, and UV resistance and optical characteristics are good. / T2 is 30 or less, more preferably 20 or less, and particularly preferably 15 or less.

In the laminated sheet of the present invention, the P2 layer thickness T2 is preferably 3.5 μm or more. More preferably, it is 5 micrometers or more, More preferably, it is 7 micrometers or more, Most preferably, it is 10 micrometers or more. If the layer thickness T2 of the P2 layer is less than 3.5 μm, the effect of improving the characteristics due to the addition of inorganic particles tends to be reduced. In the laminated sheet of the present invention, the effect of adding particles can be exhibited by setting the layer thickness T2 of the P2 layer to 3.5 μm or more. The upper limit of the layer thickness T2 of the P2 layer is not particularly limited, but the range in which T1 / T2 satisfies the above formula (I) satisfies the moist heat resistance and heat resistance of the laminated sheet, and the laminate This is preferable in that curling is suppressed when the sheet has an asymmetric configuration.
Moreover, it is preferable that the lamination sheet of this invention is measured based on ASTM-D882-97 (referred to 1999 edition ANNUAL BOOK OF ASTM STANDARDS) and has a breaking elongation of 20% or more. More preferably, it is 50% or more, More preferably, it is 70% or more. By setting it as such a range, it becomes possible to use a laminated sheet suitably for solar cell backsheets.

The laminated sheet of the present invention preferably has an elongation retention of 20% or more after treatment for 48 hours in an atmosphere of a temperature of 125 ° C. and a humidity of 100% RH. More preferably, it is 30% or more, further preferably 40% or more, and particularly preferably 50% or more. The elongation retention here is measured based on ASTM-D882-97 (referred to 1999 edition ANNUAL BOOK OF ASTM STANDARDS), and is the elongation at break E0 of the laminated sheet before treatment, When the breaking elongation after the treatment is E1, it is a value obtained by the following equation (2).
Elongation retention (%) = (E1 / E0) × 100 (2)
In the measurement, the sample was cut out into the shape of a measurement piece, then processed, and the processed sample was measured. By setting it as such a range, the heat-and-moisture resistance of a lamination sheet becomes still better, and the heat-and-moisture resistance of the solar cell using the lamination sheet of this invention can be made favorable.

The laminated sheet of the present invention preferably has an elongation retention rate of 20% or more after being treated at a temperature of 160 ° C. for 500 hours. More preferably, it is 30% or more, more preferably 40% or more, particularly preferably 50% or more, and most preferably 60%. The elongation retention here is measured based on ASTM-D882-97 (referred to 1999 edition ANNUAL BOOK OF ASTM STANDARDS), and is the elongation at break E0 ′ of the laminated sheet before processing. When the breaking elongation after the treatment is E ′, it is a value obtained by the following equation (2 ′).
Elongation retention (%) = (E1 ′ / E0 ′) × 100 (2 ′)
In the measurement, the sample was cut out into the shape of a measurement piece, then processed, and the processed sample was measured. By setting it as such a range, the heat resistance of a laminated sheet becomes still better, and the heat resistance of the solar cell using the laminated sheet of this invention can be made favorable.
The laminated sheet of the present invention has an elongation retention rate of 20% after being irradiated for 1000 hours with a xenon lamp (wavelength range: 290 to 400 nm) having an intensity of 150 mW / cm ^{2 in} an atmosphere of a temperature of 65 ° C. and 50% RH. The above is preferable. More preferably, it is 25% or more, still more preferably 30% or more, and particularly preferably 35% or more. In addition, when irradiating the xenon lamp to the laminated sheet of the present invention, the P2 layer side of the laminated sheet of the present invention is exposed. In the measurement, the sample was cut into the shape of a measurement piece, then processed, and the processed sample was measured. By setting it as such a range, the ultraviolet-ray resistance of a lamination sheet can be made favorable.

The laminated sheet of the present invention has an elongation retention of 20% or more after being treated for 48 hours in an atmosphere of a temperature of 125 ° C. and a humidity of 100% RH, and has an intensity of 150 mW / day in an atmosphere of a temperature of 65 ° C. and 50% RH. It is preferable that the elongation retention after irradiation with a cm ² xenon lamp (wavelength range: 290 to 400 nm) for 1000 hours is 20% or more. A laminated sheet that satisfies this range can be applied as a back sheet for solar cells, for example, because it can be superior in moisture and heat resistance and ultraviolet resistance to conventional laminated sheets made of polycarbonate resin. In this case, the mechanical strength can be maintained for a long time.

  The laminated sheet of the present invention can be laminated with other films and the like. Examples of such other films include polyester layers for increasing mechanical strength, antistatic layers, adhesion layers with other materials, UV resistant layers for further improving UV resistance, and difficulty for imparting flame resistance. A fuel layer, a hard coat layer for improving impact resistance and scratch resistance, and the like can be arbitrarily selected depending on the application. As a specific example, when the laminated sheet of the present invention is used as a back sheet for a solar cell, the adhesion to other sheet materials or a sealing material (for example, ethylene vinyl acetate) in which a power generation element is embedded is further increased. In order to improve, in addition to an easy-adhesion layer, an ultraviolet resistant layer, a flame retardant layer, a conductive layer for improving a voltage at which a partial discharge phenomenon, which is an index of insulation, is generated can be used.

  Next, the manufacturing method of the lamination sheet of this invention is given and demonstrated.

  In the laminated sheet of the present invention, the polycarbonate-based resin that is the main constituent of the P1 layer can be obtained by reacting a dihydroxydiaryl compound with phosgene or a carbonate such as diphenyl carbonate by a known method. Also, commercially available polycarbonate systems such as “Taflon” manufactured by Idemitsu Kosan Co., Ltd., “Banlite” manufactured by Teijin Kasei Co., Ltd., “Novalex” manufactured by Mitsubishi Engineering Plastics Co., Ltd., and “Caliver” manufactured by Sumitomo Dow Co., Ltd. Resins can also be suitably used.

  In the laminated sheet of the present invention, the polybutylene terephthalate resin, which is the main component of the P2 layer, contains terephthalic acid or a derivative thereof as a dicarboxylic acid component, 1,4 butanediol as a diol component, and an esterification reaction from other copolymer components. It can be obtained by conducting a polycondensation reaction through a transesterification reaction. Further, if necessary, it is also preferable to heat the chip obtained by the polycondensation reaction under reduced pressure to increase the molecular weight by a solid phase polymerization reaction.

In the laminated sheet of the present invention, as a method for laminating the P1 layer and the P2 layer, for example, a cast drum in which the raw material for the P1 layer and the raw material for the P2 layer are respectively charged into two extruders and melted and cooled from the die A method of coextrusion and processing into a sheet (coextrusion method), a method of laminating a raw material of a coating layer into a sheet produced by a single film into an extruder, melting and extruding from a die (melt lamination method), Each film is prepared separately, and heat-pressed with a heated group of rolls (thermal laminating method), bonded with an adhesive (adhesive method), and other solutions dissolved in a solvent A drying method (coating method), a method combining these, and the like can be used. Of these, the coextrusion method is preferable in that the production process is short and the adhesion between the layers is good. Hereafter, the manufacturing method by a coextrusion method is explained in full detail.
When adding inorganic particles to the polycarbonate-based resin constituting the P1 layer, the method is preferably a method in which the polycarbonate-based resin and the inorganic particles are melt-kneaded in advance using a vented biaxial kneading extruder or tandem type extruder. . Here, since the heat history is received when the inorganic particles are contained, the polycarbonate-based resin is deteriorated. Therefore, a high-concentration master pellet with a larger amount of inorganic particles added than the amount of inorganic particles contained in the P1 layer is prepared, mixed with a polycarbonate resin, and diluted to obtain a predetermined P1 layer inorganic particle content. Is preferable from the viewpoint of heat and moisture resistance.
At this time, the concentration of the high concentration master pellet is preferably 20% by mass or more and 80% by mass or less, more preferably 25% by mass or more and 70% by mass or less, still more preferably 30% by mass or more and 60% by mass or less, and particularly preferably. It is 40 mass% or more and 60 mass% or less. When the amount is less than 20% by mass, the amount of the master batch added to the P1 layer is increased, and as a result, the amount of the polycarbonate-based resin deteriorated in the P1 layer is increased, and the heat and moisture resistance may be lowered. On the other hand, when it exceeds 80% by mass, it may be difficult to form a masterbatch, or it may be difficult to mix uniformly when the masterbatch is mixed with a polycarbonate resin.
In addition, when adding inorganic particles to the polybutylene terephthalate resin constituting the P2 layer, the method is to melt the polybutylene terephthalate resin and inorganic particles in advance using a vented twin-screw kneading extruder or tandem extruder. A method of kneading is preferred. Here, since the thermal history is received when the inorganic particles are contained, the polybutylene terephthalate resin is deteriorated. Therefore, a high-concentration master pellet having a larger amount of inorganic particles added than the amount of inorganic particles contained in the P2 layer is prepared, mixed with a polybutylene terephthalate resin, diluted, and the predetermined P2 layer inorganic particle content It is preferable from the viewpoint of the mechanical strength of the P2 layer.
At this time, the concentration of the high concentration master pellet is preferably 20% by mass or more and 80% by mass or less, more preferably 25% by mass or more and 70% by mass or less, still more preferably 30% by mass or more and 60% by mass or less, and particularly preferably. It is 40 mass% or more and 60 mass% or less. When the amount is less than 20% by mass, the amount of the master batch added to the P2 layer increases, and as a result, the amount of the polybutylene terephthalate resin deteriorated in the P2 layer increases, and the mechanical strength of the P2 layer may decrease. is there. On the other hand, when it exceeds 80% by mass, it may be difficult to form a master batch, or it may be difficult to uniformly mix the master batch with a polybutylene terephthalate resin.

  Next, when producing the laminated sheet of the present invention by a coextrusion method, first, after drying the composition for P1 layer mixed with the polycarbonate-based resin raw material and the master pellet containing inorganic particles, under a nitrogen stream or under reduced pressure, It is supplied to an extruder heated to 240 ° C. or higher and 300 ° C. or lower, more preferably 250 ° C. or higher and 290 ° C. or lower, and melted. Moreover, after drying the composition for P2 layer which mixed the polybutylene terephthalate-type resin raw material and the master pellet containing an inorganic particle, it is 200 degreeC or more and 270 degrees C or less under nitrogen stream or pressure reduction, More preferably, 220 degreeC or more and 250 degrees C or less The mixture is supplied to another extruder heated in the melt and melted. Next, the P1 layer and the P2 layer are merged and laminated using a multi-manifold die, a feed block, a static mixer, pinol, or the like, and coextruded from the die.

  The laminate sheet of the present invention can be obtained by extruding the laminate sheet discharged from the die by the above method onto a cooling body such as a casting drum and cooling and solidifying it. At this time, it is preferable that the temperature of the cooling body at the time of the first stage cooling is 10 ° C. or higher and the glass transition temperature of the polycarbonate-based resin of the P1 layer is −10 ° C. or lower. At this time, it is preferable to use a wire-like, tape-like, needle-like, or knife-like electrode to adhere to a cooling body such as a casting drum by electrostatic force. Furthermore, the temperature of the cooling body may be not higher than the glass transition temperature of the polybutylene terephthalate resin of the P2 layer, more preferably the temperature of the cooling body may be −5 ° C. or lower of the glass transition temperature of the polybutylene terephthalate resin of the P2 layer. More preferred is that excessive crystallization of polybutylene terephthalate can be suppressed and the moisture and heat resistance of the laminated sheet can be further improved.

The laminated sheet of the present invention obtained by the above method may be subjected to a processing treatment such as a heat treatment, if necessary, as long as the effects of the present invention are not impaired. As the upper limit of the heat treatment temperature, the glass transition temperature of the P1 polycarbonate resin is −10 ° C. or lower, more preferably the glass transition temperature −20 ° C. or lower, more preferably the glass transition temperature − 30 ° C. or lower. The heat treatment time is 5 seconds or more and 30 minutes or less. By heat-treating, the thermal dimensional stability of the laminated sheet of the present invention can be improved.
In the laminated sheet of the present invention, as a method of laminating with other films, for example, when the material of each layer to be laminated is mainly thermoplastic resin, different materials are put into different extruders and melted. Co-extrusion onto a cast drum cooled from the die and processing it into a sheet (co-extrusion method), and the raw material of the coating layer is put into an extruder and melt extruded and laminated while extruding from the die. Method (melt laminating method), each film is prepared separately, heat-pressed by a heated group of rolls (heat laminating method), method of bonding via an adhesive (adhesion method), and other solvents A method (coating method) of applying and drying the dissolved material, a method combining these, and the like can be used.
The laminated sheet of the present invention can be produced by the above method. The obtained laminated sheet is excellent in moisture and heat resistance, ultraviolet resistance, and optical properties (light reflectivity, whiteness, etc.) as compared with a conventional polycarbonate resin sheet. Such laminated sheets are suitable for applications where importance is placed on wet heat resistance, resistance to ultraviolet rays, and light reflectivity, including back plates for solar cells, liquid crystal display reflectors, automotive materials, and building materials. Can be used. In particular, by using such a laminated sheet, a solar cell backsheet having high durability and a solar cell using the same can be provided.

  The solar cell of the present invention is characterized by using the laminated sheet of the present invention as a back sheet. By using the laminated sheet of the present invention, it becomes possible to increase the durability or to make it thinner as compared to conventional solar cells. An example of the configuration is shown in FIG. A power generating element connected with a lead wire for taking out electricity (not shown in FIG. 1) is sealed with a transparent sealing material layer 2 such as EVA resin, a transparent substrate 4 such as glass, and the present invention. The laminated sheet is configured to be bonded as the solar cell backsheet 1, but is not limited thereto, and can be used for any configuration. In addition, although the example by the lamination sheet single-piece | unit of this invention was shown in FIG. 1, it is also possible to use the composite sheet of the lamination sheet of this invention and another film according to the other required required characteristic.

  Here, in the solar cell of the present invention, the above-described solar cell backsheet 1 is installed on the back surface of the sealing material layer 2 in which the power generation element is sealed. Here, it is preferable that the P2 layer of the laminated sheet of the present invention is disposed at least on the side opposite to the sealing material layer 2 (6 in FIG. 1). By adopting this configuration, it becomes possible to increase resistance to ultraviolet rays reflected from the ground, and a highly durable solar cell can be obtained or the thickness can be reduced. Further, in the case where the laminated sheet of the present invention has an asymmetric configuration and the other one-side surface is composed of the P1 layer, the P1 layer is disposed so as to be positioned on the sealing material layer 2 side. This is preferable in that the adhesion to the stopper can be further increased.

  The power generating element 3 converts light energy of sunlight into electric energy, and is based on crystalline silicon, polycrystalline silicon, microcrystalline silicon, amorphous silicon, copper indium selenide, compound semiconductor, dye enhancement Arbitrary elements such as a sensitive system can be used in series or in parallel according to the desired voltage or current depending on the purpose.

  Since the transparent substrate 4 having translucency is located on the outermost surface layer of the solar cell, a transparent material having high weather resistance, high contamination resistance, and high mechanical strength characteristics in addition to high transmittance is used. In the solar cell of the present invention, the transparent substrate 4 having translucency can be made of any material as long as the above characteristics are satisfied. Examples thereof include glass, tetrafluoroethylene-ethylene copolymer (ETFE), polyfluoride. Vinyl fluoride resin (PVF), polyvinylidene fluoride resin (PVDF), polytetrafluoroethylene resin (TFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polytrifluoroethylene chloride resin (CTFE) ), Fluorinated resins such as polyvinylidene fluoride resin, olefinic resins, acrylic resins, and mixtures thereof. In the case of glass, it is more preferable to use a tempered glass. Moreover, when using the resin-made translucent base material, what extended | stretched the said resin uniaxially or biaxially from a viewpoint of mechanical strength is used preferably.

  Further, in order to provide these substrates with adhesion to an EVA resin or the like that is a sealing material for the power generation element, it is preferable to subject the surface to corona treatment, plasma treatment, ozone treatment, and easy adhesion treatment. Is called.

  The sealing material 2 for sealing the power generation element is formed by covering and fixing the unevenness of the surface of the power generation element with a resin, protecting the power generation element from the external environment, and having a light-transmitting base material for the purpose of electrical insulation In addition, a material having high transparency, high weather resistance, high adhesion, and high heat resistance is used to adhere to the backsheet and the power generation element. Examples thereof include ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA) resin, ethylene-methacrylic acid copolymer (EMAA), Ionomer resins, polyvinyl butyral resins, and mixtures thereof are preferably used.

  As described above, by incorporating the solar cell backsheet used in the laminated sheet of the present invention into the solar cell system, it is possible to obtain a highly durable and / or thin solar cell system compared to conventional solar cells. It becomes. The solar cell of the present invention can be suitably used for various applications without being limited to outdoor use and indoor use such as a solar power generation system and a power source for small electronic components.

[Characteristic evaluation method]
A. Layer thickness T1, T2, stacking ratio T1 / T2
It calculated | required in the procedure of following (A1)-(A4). The measurement was performed at 10 different places, and the average value was defined as the layer thickness T1 (μm) of the P1 layer, the layer thickness T2 (μm) of P2, and the stacking ratio T1 / T2.
(A1) Using a microtome, the laminate sheet is cut perpendicular to the laminate sheet surface direction without crushing the laminate sheet in the thickness direction.
(A2) Next, the cut section is observed using an electron microscope, and an image magnified 500 times is obtained. In addition, although an observation place shall be defined at random, the up-down direction of an image shall be parallel to the thickness direction of a lamination sheet, and the left-right direction of an image shall be parallel to the surface direction of a lamination sheet, respectively. When the entire thickness direction does not fit in one image, observation is performed by shifting the observation position in the thickness direction, and an image that can confirm the entire thickness is prepared by combining a plurality of images.
(A3) The layer thickness T1 of the P1 layer and the layer thickness T2 of the layer P2 in the image obtained in (A2) were determined.
(A4) T1 was divided by T2, and the lamination ratio T1 / T2 was calculated.

B. Inorganic particle content Wa1, Wa2, Wave
Each of the P1 layer and the P2 layer was cut out from the laminated sheet, and the inorganic particle contents Wa1 and Wa2 were determined by the following method.
For the P1 layer, the mass wa1 (g) of what was cut out was measured. Subsequently, it was made to melt | dissolve in a methylene chloride, and the inorganic particle was fractionated among the insoluble components by centrifugation. The obtained inorganic particles were washed with methylene chloride and centrifuged. The washing operation was repeated until no white turbidity occurred even when ethanol was added to the washing solution after centrifugation. The mass wa ′ (g) of the obtained inorganic particles was obtained, and the inorganic particle content (mass%) Wa1 = (wa1 ′ / wa1) × 100 obtained by measuring the inorganic particle content Wa1 from the following formula (3). (3)
In the P2 layer, when the polycarbonate resin is the main constituent, the inorganic particle content Wa2 of the P2 layer was determined by the same method as in the P1 layer.
In addition, when the P2 layer was mainly composed of polybutylene terephthalate resin, the mass wa2 (g) of the shaved material was measured. Subsequently, it was made to melt | dissolve in chloroform / hexafluoro isopropanol = 1/1 solution, and the inorganic particle was fractionated among the insoluble components by centrifugation. The obtained inorganic particles were washed with chloroform / hexafluoroisopropanol = 1/1 solution and centrifuged. The washing operation was repeated until no white turbidity occurred even when ethanol was added to the washing solution after centrifugation. The mass wa2 ′ (g) of the obtained inorganic particles was determined, and the inorganic particle content Wa2 (mass%) of the P2 layer, which was measured from the following formula (4), was (wa2 ′ / wa2) × 100. ... (4)
Moreover, the inorganic particle content rate Wave of the P1 layer and the P2 layer was obtained by the following formula (1).
Average Wave of Inorganic Particle Content Wave = (Wa1 × T1 + Wa2 × T2) / (T1 + T2) (1)
However, T1 is the layer thickness (μm) of the P1 layer, and T2 is the layer thickness (μm) of the P2 layer.

C. Breaking elongation measurement Based on ASTM-D882 (referred to ANNUAL BOOK OF ASTM STANDARDDS 1999 edition), a sample was cut into a size of 1 cm × 20 cm, and the elongation at break when the sample was pulled at 5 cm between chucks and at a pulling speed of 300 mm / min. The degree was measured. The number of samples was n = 5, and after measuring for each of the laminated sheet in the longitudinal direction and the transverse direction, the average value thereof was obtained.
D. After cutting the sample of elongation retention after the heat resistance test into the shape of a measurement piece (1 cm × 20 cm), it is processed for 500 hours at 160 ° C. in a gear oven GPHH-102 manufactured by Espec Co., Ltd. And then the above C.I. The elongation at break was measured according to the item. In addition, the measurement was made into n = 5, and after measuring about 5 samples of the vertical direction of a laminated sheet, and a horizontal direction, the average value was made into breaking elongation E1 '. In addition, the C.I. The elongation at break E0 ′ was measured according to the item, and the elongation retention was calculated by the following equation (2 ′) using the obtained elongation at break E0 ′ and E1 ′.
Elongation retention (%) = (E1 ′ / E0 ′) × 100 (2 ′)
The obtained elongation retention was determined as follows.
When elongation retention is 60% or more: S
When the elongation retention is 50% or more and less than 60%: A
When the elongation retention is 40% or more and less than 50%: B
When the elongation retention is 30% or more and less than 40%: C
When the elongation retention is 20% or more and less than 30%: D
When the elongation retention is less than 20%: E
S to D are good, and S is the best among them.

E. Elongation retention% after wet heat resistance test
After the sample was cut into the shape of a measurement piece (1 cm × 20 cm), it was treated with a pressure cooker manufactured by Hirayama Seisakusho at a temperature of 125 ° C. and a relative humidity of 100% RH for 48 hours. . The elongation at break was measured according to the item. In addition, the measurement was made into n = 5, and after measuring about 5 samples of the vertical direction and the horizontal direction of a lamination sheet, the average value was made into elongation at break E1. In addition, the C.I. The elongation at break E0 was measured according to the item, and the elongation retention was calculated by the following equation (2) using the obtained elongation at break E0, E1.
Elongation retention (%) = (E1 / E0) × 100 (2)
The obtained elongation retention was determined as follows.
When the elongation retention is 50% or more: S
When the elongation retention is 40% or more and less than 50%: A
When the elongation retention is 30% or more and less than 40%: B
When the elongation retention is 25% or more and less than 30%: C
When the elongation retention is 20% or more and less than 25%: D
When the elongation retention is less than 20%: E
S to D are good, and S is the best among them.

F. An elongation retention sample after the light resistance test was cut into the shape of a measurement piece (1 cm × 20 cm), and then at a temperature of 65 ° C., a relative humidity of 50% RH, and strength using a Xenon Weather Meter SC750 manufactured by Suga Test Instruments Co., Ltd. Irradiation for 1000 hours under conditions of 150 mW / cm ² (light source: xenon lamp, wavelength range: 290 to 400 nm), and then C.I. The elongation at break was measured according to the item. In addition, the measurement was made into n = 5, and after measuring about each of the vertical direction and the horizontal direction of a film, the average value was made into breaking elongation E2. In addition, the C.I. The elongation at break E0 was measured according to the item, and the elongation retention was calculated by the following equation (5) using the elongation at break E0, E2 thus obtained.
Elongation retention (%) = (E2 / E0) × 100 (5)
The obtained elongation retention was determined as follows.
When the elongation retention is 55% or more: S
When the elongation retention is 45% or more and less than 55%: A
When the elongation retention is 35% or more and less than 45%: B
When the elongation retention is 25% or more and less than 35%: C
When the elongation retention is 20% or more and less than 25%: D
When the elongation retention is less than 20%: E
S to D are good, and S is the best among them. In addition, when the lamination sheet was asymmetrical, it irradiated with ultraviolet rays from the P2 layer side of the lamination sheet of the present invention.

G. Relative reflectance spectrophotometer U-3410 (manufactured by Hitachi, Ltd.) was used to measure the reflectance at a wavelength of 560 nm to obtain a relative reflectance. The number of samples was n = 5, and the relative reflectance of each sample was measured, and the average value was calculated. The measuring unit used an integrating sphere (model number 130-0632) with a diameter of 60 mm, and a 10 ° inclined spacer was attached. Moreover, aluminum oxide (model number 210-0740) was used for the standard white plate. When the laminated sheet has an asymmetric configuration, the measurement was made from the P2 layer side of the laminated sheet.
The obtained reflectance was determined as follows.
When the relative reflectance is 94% or more: S
When the relative reflectance is 92% or more and less than 94%: A
When the relative reflectance is 89% or more and less than 92%: B
When the relative reflectance is 85% or more and less than 89%: C
When the relative reflectance is less than 85%: D
S to C are good, and S is the best among them.
H. Color tone (b value)
Based on JIS-Z-8722 (1994 version), a spectroscopic color difference meter (SE-2000 manufactured by Nippon Denshoku Industries Co., Ltd., light source halogen lamp 12V, 4A, 0 ° to −45 ° post-spectral method) is used to reflect the sheet. The color tone (b value) of was measured.
H. Color change Δb after UV irradiation
The laminated sheet was subjected to 1000 hours under the conditions of a temperature of 65 ° C., a relative humidity of 50%, and an intensity of 150 mW / cm ² (light source: xenon lamp, wavelength range: 290 to 400 nm) using a xenon weather meter SC750 manufactured by Suga Test Instruments Co., Ltd. The b value after irradiation and the b value before and after the test were measured according to the G term, and the difference between them was defined as a color tone change Δb after ultraviolet irradiation.
The obtained color tone change (Δb) was determined as follows.
When the color change Δb is 2 or less: S
When the color change Δb is greater than 2 and less than or equal to 3: A
When the color change Δb is greater than 3 and less than or equal to 3.5: B
When the color change Δb is greater than 3.5 and less than or equal to 4: C
When the color change Δb is greater than 4 and less than or equal to 5: D
When the color change Δb is greater than 5: E
S to D are good, and S is the best among them.
In addition, when the lamination sheet was asymmetrical, it irradiated with ultraviolet rays from the P2 layer side of the lamination sheet of the present invention.

I. Adhesiveness Based on JIS K 6854 (1994 edition), the adhesive strength with the EVA sheet was measured. The test specimen is a commercially available glass laminator formed by stacking a 500 μm thick EVA sheet manufactured by Sanvic Co., Ltd., and a corona-treated Example and Comparative Example laminated sheet on a semi-tempered glass having a thickness of 0.3 mm. After pressurizing using a pressure of 135 ° C. under a heating condition of 135 ° C. under a load of 29.4 N / cm ² for 15 minutes. The width of the test piece for the adhesive strength test was 10 mm, two test pieces were prepared, and each test piece was measured at three locations by changing the location, and the average value of the obtained measured values was used as the value of the adhesive strength. It is judged that the adhesive strength is 100 N / 50 mm or more as a practically acceptable level.
When the peel strength determined as follows is 65 N / 10 mm or more: S
When the peel strength is 55 N / 10 mm or more and less than 65 N / 10 mm or more: A
When peel strength is 45 N / 10 mm or more and less than 55 N / 10 mm or more: B
When peel strength is 35 N / 15 mm or more and less than 45 N / 10 mm or more: C
When the peel strength is 25 N / 10 mm or more and less than 35 N / 10 mm or more: D
When peel strength is less than 25 N / 10 mm: E
S to D are good, and S is the best among them.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not necessarily limited to these.

(material)
・ Polycarbonate resin (PC (1))
“Taflon” A2200 manufactured by Idemitsu Kosan Co., Ltd. was used. This polycarbonate resin is a polycarbonate resin mainly composed of 2,2-bis (4-hydroxyphenyl) propane (commonly referred to as bisphenol A) as a dihydroxydiaryl compound, at a temperature of 300 ° C. and a load of 1.2 kg. MVR is a 12cm ³ / 10min.

・ Polycarbonate resin (PC (2))
“Taflon” A2600 manufactured by Idemitsu Kosan Co., Ltd. was used. This polycarbonate resin is a polycarbonate resin mainly composed of 2,2-bis (4-hydroxyphenyl) propane (commonly referred to as bisphenol A) as a dihydroxydiaryl compound, at a temperature of 300 ° C. and a load of 1.2 kg. MVR is a ^6cm 3 / 10min.

・ Polybutylene terephthalate resin (PBT)
“Toraycon” 1400S manufactured by Toray Industries, Inc. was used. The polybutylene terephthalate resin is a polybutylene terephthalate resin mainly composed of terephthalic acid as a dicarboxylic acid component and butanediol as a diol component.

(Reference Example 1)
50 parts by mass of PC (1) and 50 parts by mass of rutile titanium oxide particles having an average particle size of 210 nm were melt-kneaded in a vented 260 ° C. twin-screw kneading extruder, melt-extruded, and discharged in the form of a strand. After cooling with water at a temperature of 25 ° C., cutting was performed immediately to prepare a master batch (MB1) having a titanium oxide particle concentration of 50 mass%.

(Reference Example 2)
A master batch (MB2) having a titanium oxide particle concentration of 50 mass% was prepared in the same manner as in Reference Example 1 except that PC (2) was used as the polycarbonate resin.

(Reference Example 3)
50 parts by mass of PBT and 50 parts by mass of rutile titanium oxide particles having an average particle diameter of 210 nm were melt-kneaded in a vented 230 ° C. twin-screw kneading extruder, melt-extruded, and discharged in a strand form. After cooling with water at a temperature of 25 ° C., cutting was performed immediately to prepare a master batch (MB3) having a titanium oxide particle concentration of 50 mass%.

(Reference Example 4)
A master batch (MB4) containing 50% by mass of zinc oxide particles was obtained in the same manner as in Reference Example 3 except that 50 parts by mass of zinc oxide particles having an average particle size of 290 nm were used.

Example 1
Using the main extruder and the sub-extruder, the main extruder (single screw extruder), the PC (1), and the titanium oxide master batch (MB1) obtained in Reference Example 1 are shown in Table 1. What was mixed so that it might become the composition of P1 layer shown was dried after hot-air drying at a temperature of 110 ° C. for 6 hours, and was melted and extruded at a temperature of 280 ° C., followed by filtration through an 80 μm cut filter. On the other hand, the sub-extruder was prepared by mixing PBT and the titanium oxide master batch (MB3) obtained in Reference Example 3 so that the titanium oxide content was the composition of the P2 layer shown in Table 1, After hot-air drying at a temperature of 110 ° C. for 6 hours, the mixture was supplied and melt extruded. Next, the P2 layer supplied from the sub-extruder is joined to both sides of the P1 layer supplied from the main extruder so that the layer thickness ratio is P2 layer: P1 layer: P2 layer = 1: 4: 1, From the inside of the T die die, melted two-layer lamination coextrusion is carried out to obtain a laminated sheet, which is closely cooled and solidified by an electrostatic application method on a drum maintained at a surface temperature of 20 ° C., and then cooled to room temperature to have a thickness of 300 μm. A laminated sheet was obtained.
Table 1 shows the results of determining the layer thickness and lamination ratio of the obtained laminated sheet, and Table 2 shows the results of evaluating the sheet characteristics. As a result, as shown in Table 2, it was found that the laminated sheet was excellent in heat resistance and ultraviolet resistance. Moreover, light reflectivity, adhesiveness, and heat-and-moisture resistance were also favorable.

(Examples 2 to 13)
A laminated sheet having a thickness of 300 μm was prepared in the same manner as in Example 1 except that the composition of the P1 layer and the P2 layer was changed to the composition shown in Table 1, and the ratio of the thicknesses of the P1 layer and the P2 layer was changed to that shown in Table 1. Obtained. The results of evaluating the characteristics of the obtained laminated sheet are shown in Tables 1 and 2. It was found that the laminated sheet is excellent in heat resistance and ultraviolet resistance. Moreover, light reflectivity, adhesiveness, and heat-and-moisture resistance were also favorable. Moreover, about Examples 5-13, compared with Examples 1-4, the characteristic balance of heat resistance, ultraviolet-ray resistance, light reflectivity, adhesiveness, and heat-and-moisture resistance was favorable.

(Example 14)
The composition of the P1 layer and the P2 layer is set to the composition shown in Table 1, and the P2 layer supplied from the sub-extruder is arranged on one side of the P1 layer supplied from the main extruder in the thickness ratio, P1 layer: P2 layer A laminated sheet having a thickness of 300 μm was obtained in the same manner as in Example 1 except that they were merged so as to be 4: 1. The results of evaluating the characteristics of the obtained laminated sheet are shown in Tables 1 and 2. All were found to be laminated sheets excellent in heat resistance, ultraviolet resistance, light reflectivity, and moist heat resistance.

(Example 15)
A laminated sheet having a thickness of 300 μm as in Example 1 except that the composition of the P1 layer and the P2 layer is changed to the composition shown in Table 1, and the ratio of the layer thicknesses of the P1 layer and the P2 layer is changed to that shown in Table 1. Got. The results of evaluating the characteristics of the obtained laminated sheet are shown in Tables 1 and 2. The laminated sheet was found to be a laminated sheet having excellent heat resistance and ultraviolet resistance. Moreover, light reflectivity, adhesiveness, and heat-and-moisture resistance were also favorable.

(Example 16)
Example except that the P2 layer particles are zinc oxide particles, the composition of the P1 layer and the P2 layer is the composition of Table 1, and the ratio of the layer thicknesses of the P1 layer and the P2 layer is changed to that of Table 1. As in Example 1, a laminated sheet having a thickness of 300 μm was obtained. The results of evaluating the characteristics of the obtained laminated sheet are shown in Tables 1 and 2. The laminated sheet was found to be a laminated sheet having excellent heat resistance and ultraviolet resistance. Moreover, light reflectivity, adhesiveness, and heat-and-moisture resistance were also favorable.

(Comparative Examples 1-6)
A laminated sheet having a thickness of 300 μm was obtained in the same manner as in Example 1 except that the compositions of the P1 layer and the P2 layer were changed to the compositions shown in Table 1. The results of evaluating the characteristics of the obtained laminated sheet are shown in Tables 1 and 2.
In Comparative Examples 1, 4, 5 and 6, the heat resistance of the laminated sheet was inferior. In Comparative Examples 2 to 5, the ultraviolet resistance was inferior.
(Comparative Example 7)
The resin, which is the main component of the P2 layer, is a PC resin, the compositions of the P1 layer and P2 layer are the compositions shown in Table 1, and the drum surface temperature is 70 ° C. A 300 μm laminated sheet was obtained. The results of evaluating the characteristics of the obtained laminated sheet are shown in Tables 1 and 2. The results were inferior in ultraviolet resistance compared to the examples.

The laminated sheet of the present invention can provide a laminated sheet having excellent resistance to ultraviolet rays as compared with a conventional polycarbonate resin sheet and having moisture and heat resistance and heat resistance applicable to a solar cell backsheet. Such a laminated resin sheet is suitably used for applications in which resistance to ultraviolet rays and light reflectivity are important, such as a back sheet for a solar cell, a reflection plate for a liquid crystal display, an automobile material, and a building material. be able to. In particular, by using such a polycarbonate resin sheet, it is possible to provide a solar cell backsheet having high durability and a solar cell using the solar cell backsheet.

1: Solar cell backsheet 2: Sealing material layer 3: Power generation element 4: Transparent substrate 5: Surface on the sealing material layer 2 side of the solar cell backsheet 6: Sealing material layer 2 of the solar cell backsheet Opposite side

Claims (7)

A layer (P1 layer) mainly composed of a polycarbonate-based resin and a layer (P2 layer) composed mainly of a polybutylene terephthalate-based resin and having an inorganic particle content Wa2 of 2% by mass or more and 20% by mass or less. A laminated sheet, wherein the ratio T1 / T2 of the layer thickness T1 of the P1 layer and the layer thickness T2 of the P2 layer satisfies the following formula (I):
(Wa2 + 16) / 9 ≦ T1 / T2 (I) The laminated sheet according to claim 1, wherein the P1 layer contains inorganic particles, and the P1 layer has an inorganic particle content Wa1 of 0.1% by mass or more and 15% by mass or less. The laminated sheet according to claim 1 or 2, wherein a ratio Wa1 / Wa2 between the inorganic particle content Wa1 of the P1 layer and the inorganic particle content Wa2 of the P2 layer is 0.8 or less. One outermost layer of the laminated sheet is a P2 layer The solar cell backsheet using the lamination sheet in any one of Claims 1-4. The solar cell backsheet according to claim 5, wherein at least one outermost layer is a P2 layer. The solar cell using the solar cell backsheet of Claim 6 or 7.

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