WO2013015259A1

WO2013015259A1 - Laminated sheet and method for producing same

Info

Publication number: WO2013015259A1
Application number: PCT/JP2012/068651
Authority: WO
Inventors: 塩見篤史; 青山滋; 巽規行; 高橋弘造
Original assignee: 東レ株式会社
Priority date: 2011-07-26
Filing date: 2012-07-24
Publication date: 2013-01-31
Also published as: TW201316526A; JPWO2013015259A1

Abstract

The present invention provides a laminated sheet having both flame resistance and curl properties when compared to a conventional laminated sheet of a polycarbonate resin and polyolefin resin. Also provided is a high-durability back sheet for a solar cell, realized by using the laminated sheet, and a solar cell using the back sheet. The laminated sheet comprises a laminated structure having a layer (P1 layer) whose primary structural component is a polycarbonate resin, an adhesive layer (P2 layer), and a layer (P3 layer) whose primary structural component is a polyolefin resin, wherein at least one surface layer is the P3 layer. The laminated sheet satisfies formulas (1) and (2) where the thickness of the P1 layer of the laminated sheet is T1, thickness of the P2 layer is T2, and thickness of the P3 layer is T3. T1/T3 > 0.5··· (1) T2 > 12 µm··· (2)

Description

Laminated sheet and method for producing the same

The present invention relates to a laminated sheet capable of achieving both flame retardancy and curl characteristics. In particular, the present invention relates to a laminated sheet that can be suitably used as a back sheet for a solar cell, and a method for producing the laminated sheet.

In recent years, photovoltaic power generation has attracted attention as a semi-permanent and pollution-free next-generation energy source, and solar cells are rapidly spreading. A solar cell is composed of a power generation element sealed with a transparent sealing material such as ethylene-vinyl acetate copolymer (EVA), and a transparent substrate such as glass and a resin sheet called a back sheet bonded together. The Sunlight is introduced into the solar cell through the transparent substrate. Sunlight introduced into the solar cell is absorbed by the power generation element, and the absorbed light energy is converted into electrical energy. The converted electric energy is taken out by a lead wire connected to the power generation element and used for various electric devices. Here, the structure which provides gas barrier property and an electrical property by pasting together various raw materials to the biaxially-stretched polyethylene terephthalate (PET) which is a cheap and high-performance with the back laminate has been examined. In addition to gas barrier properties, the olefin resin is a material generally used as a back sheet because it has good adhesion to the sealing material.

On the other hand, in order to increase the productivity of backsheets, the process of dry lamination has been omitted and coextrusion has been studied, but coextrusion is possible due to differences in glass transition temperature and crystallinity even when PET and olefin are coextruded. Is difficult and lacks heat and humidity resistance. Therefore, a back sheet based on polycarbonate that has heat and moisture resistance even when unstretched has been developed. A configuration in which olefins are laminated on both sides of the polycarbonate (Patent Document 1), and a configuration in which a polycarbonate layer is laminated on a cyclic olefin-based resin ( Patent Document 2) has been proposed.

Japanese Patent Laid-Open No. 2001-111077 JP 2006-253427 A

However, the sheet in which the olefin resin is laminated on both surface layers of the polycarbonate resin has a drawback that the flame retardance is low because the layers made of the olefin resin are provided on both surface layers of the sheet. Moreover, in the structure which provided the layer which consists of polycarbonate-type resin in the layer which consists of cyclic olefin resin, although there is a flame retardance, the whole laminated sheet from the asymmetry of the layer which consists of cyclic olefin-type resin and the layer which consists of polycarbonate-type resin When curled, when used as a solar cell backsheet, there were problems such as causing a positional deviation from the sealing material. In view of the conventional problems, the present invention provides a solar cell backsheet that achieves both flame retardancy and curl characteristics.

In order to solve the above problems, the present invention has the following configuration. That is, a laminated sheet having a layer (P1 layer) having a polycarbonate-based resin as a main component (P1 layer), an adhesive layer (P2 layer), and a layer (P3 layer) having a polyolefin-based resin as a main component, One surface layer is a P3 layer, and the P1 layer has a thickness of T1, the P2 layer has a thickness of T2, and the P3 layer has a thickness of T3, and satisfies the following formulas (1) and (2) Sheet.

T1 / T3 ≧ 0.5 (1)
T2 ≧ 12 μm (2)

According to the present invention, it is possible to provide a laminated sheet that is superior in flame retardancy and curl characteristics as compared with conventional laminated sheets of olefin resin and polycarbonate resin. Such a laminated sheet can be suitably used for a solar cell backsheet, and a high-performance solar cell can be provided by using the backsheet.

It is sectional drawing which shows typically an example of a structure of the solar cell using the lamination sheet of this invention. It is a figure which shows typically an example of the chart obtained from the measurement result of the differential scanning calorimeter (DSC).

In the present invention, it has a layer (P1 layer) mainly composed of polycarbonate-based resin, an adhesive layer (P2 layer), and a layer (P3 layer) mainly composed of polyolefin-based resin. In addition, in this specification, it says that the main component is contained exceeding 50 mass%.

In the present invention, the polycarbonate resin, which is the main component of the P1 layer, is a polymer obtained by reacting a dihydroxydiaryl compound with a carbonate such as phosgene or diphenyl carbonate. Examples of dihydroxydiaryl compounds used in polycarbonate resins include 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A), bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxy Phenyl) 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-bromophenyl) propane, 2,2-bis ( 4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3,5) Bis (hydroxyaryl) alkane compounds such as dichlorophenyl) propane, bis (hydroxyaryl) cycloalkane compounds such as 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane Compounds, dihydroxydiaryl ether compounds such as 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether, dihydroxydiaryl sulfide compounds such as 4,4′-dihydroxydiphenyl sulfide, 4 Dihydroxydiaryl sulfoxide compounds such as 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfoxide Emissions, 4,4'-dihydroxy-3,3'-dimethyl diphenyl sulfone dihydroxydiaryl sulfone compounds such as but and the like as examples without limitation. Moreover, these may be used independently or may be used in multiple types as needed.

In addition to the above-mentioned dihydroxydiaryl compound, a compound having 3 or more phenolic hydroxyl groups may be used for the polycarbonate resin in the present invention. Examples thereof 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-based 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 bisphenol A of 80 mol% or more, more preferably 90 mol% or more, and more preferably 95 mol% or more of all dihydroxydiaryl compounds used in the polycarbonate resin. (In the present specification, the same applies to the main component in the case of other structures). Furthermore, the polycarbonate-based resin that is the main component of the P1 layer is that 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A) as a dihydroxydiaryl compound can further improve heat resistance and moist heat resistance. And more preferable. The P1 layer preferably does not contain a polyolefin-based resin or is less than 3% by mass.

In the laminated sheet of the present invention, the P1 layer polycarbonate resin preferably has a number average molecular weight (Mn) of 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 P1 layer polycarbonate-based resin, the higher the moisture and heat resistance and the heat resistance. It is preferable from the viewpoint of form retention in the sealing step of the laminated sheet in the step of sealing together. According to JIS-K7122 (1987 version), the Tg was measured by heating the resin from 25 ° C. to 300 ° C. (1st RUN) at a rate of temperature increase of 20 ° C./min. In the differential scanning calorimetry chart of 2ndRUN obtained by rapidly cooling to room temperature or below and then raising the temperature from room temperature to 300 ° C. at a rate of temperature increase of 20 ° C./min. It is determined by the method described in “9.3 Determination of Glass Transition Temperature (1) Intermediate Glass Transition Temperature Tg” of JIS-K7121 (1987 edition). 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.

It is preferable that the P1 layer constituting the laminated sheet of the present invention contains inorganic particles in a range of 3% by mass to less than 50% by mass. More preferably, they are 5 mass% or more and 30 mass% or less, More preferably, they are 10 mass% or more and 20 mass% or less. The inorganic particles are used for imparting a necessary function to the sheet depending on the purpose. When it is contained in an amount of 50% by mass or more, handling properties may be deteriorated. Examples of inorganic particles that can be suitably used in the present invention include inorganic particles having ultraviolet absorbing ability, particles having a large refractive index difference from polycarbonate resins, conductive particles, pigments, and the like. Further, 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.

More specifically, as the inorganic particles in the present invention, for example, gold, silver, copper, platinum, palladium, rhenium, vanadium, osmium, cobalt, iron, zinc, ruthenium, praseodymium, chromium, nickel, aluminum, tin, Metals such as 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, zirconium oxide, oxide Metal oxides such as aluminum and silicon oxide, lithium fluoride, magnesium fluoride, aluminum fluoride, metal fluorides such as cryolite, metal phosphates such as calcium phosphate, carbonates such as calcium carbonate, barium sulfate, etc. Sulfate , Talc, kaolin and the like.

In the present invention, in view of the fact that it is often used outdoors, when metal oxides such as titanium oxide, zinc oxide, cerium oxide, etc. are used as inorganic particles having ultraviolet absorbing ability, UV resistance due to the particles By taking advantage of the properties, it is possible to exhibit the effect of reducing coloring due to deterioration of the sheet over a long period of time. 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 method of causing the polycarbonate resin constituting the P1 layer to contain inorganic particles is preferably a method in which the polycarbonate resin and the inorganic particles are melt-kneaded in advance using a vented biaxial kneading extruder or a tandem 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 having a higher inorganic particle content 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.

It is preferable that the P1 layer constituting the laminated sheet of the present invention contains organic particles in the range of 0.1% by mass or more and 20% by mass or less. Examples of the organic particles include silicone compounds, crosslinked particles such as crosslinked styrene, crosslinked acryl, and crosslinked melamine, and carbon compounds such as carbon, fullerene, carbon fiber, and carbon nanotube. In addition, in applications used outdoors, when using carbon-based materials such as particles, such as carbon, fullerene, carbon fiber, and carbon nanotube, which have ultraviolet absorbing ability, the ultraviolet absorbing ability of the particles can be utilized for a long time. In addition, the effect of the present invention that suppresses the change in color tone can be remarkably exhibited, and the sheet can also have a design property. It is preferably 0.5% by mass or more from the viewpoint of design properties, and is preferably 12% by mass or less from the viewpoint of suppressing thickening during melt extrusion caused by organic particles. More preferably, it is 1 mass% or more and 8 mass% or less.

In addition, the P1 layer and the P3 layer of the laminated sheet of the present invention may 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 an additive, it is possible to further improve the ultraviolet resistance of the laminated sheet of the present invention. In particular, in terms of improving the ultraviolet resistance of the P1 layer, a benzotriazole type ultraviolet ray It is preferable to contain an absorbent. In addition, with the addition of an antistatic agent or the like, an improvement in withstand voltage can be expected. Moreover, it is preferable that P1 layer in this invention is provided in the surface layer from a flame-retardant viewpoint.

In the present invention, an adhesive layer (P2 layer) is provided between the P1 layer and the P3 layer. The resin used for the P2 layer is preferably one that adheres to both the P1 and P3 layers. For example, low crystalline soft polymers such as acid-modified polyolefins and unsaturated polyolefins, ethylene-acrylic acid ester-maleic anhydride ternary Examples thereof include acrylic adhesives such as copolymers and ethylene vinyl acetate copolymers. Among them, it is preferable to use an acid-modified polyolefin having a polar group introduced from the viewpoint of adhesion between the P1 layer and the P3 layer. Examples of the acid-modified polyolefin include “Admer” manufactured by Mitsui Chemicals, Inc. and “Modic” manufactured by Mitsubishi Chemical Corporation as commercially available products. Further, it is preferable that the P2 layer contains a polyolefin-based elastomer in a proportion of 5% by mass or more and 50% by mass or less with respect to the P2 layer from the viewpoint that the interlayer adhesion after the wet heat treatment can be improved. Here, the interlayer adhesion after the wet heat treatment is the delamination strength after the treatment at 120 ° C. and 100% RH for 48 hours, and the details are as described in “Characteristic Evaluation Method F. Item” in the Examples. The polyolefin-based elastomer may be contained according to the required interlayer adhesion, but is preferably 10% by mass or more for improving interlayer adhesion, and is preferably 30% by mass or less from the viewpoint of cost. The polyolefin-based elastomer generally refers to a copolymer obtained by copolymerizing other α-olefin with polypropylene or polyethylene. Examples of the α-olefin include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and the like. . The polyolefin-based elastomer may be a commercially available product, for example, “Thermo Run”, “Zeras” manufactured by Mitsubishi Chemical Corporation, “Excellen”, “Tough Selenium”, “Esplen”, “Hibler” manufactured by Kuraray, Preferred examples include “Septon”, “Notio” manufactured by Mitsui Chemicals, Inc., “ENGAGE” manufactured by Dow Chemical Co., Ltd., and the like. Further, the P2 layer contains the modified styrene thermoplastic elastomer in a proportion of 3% by mass or more and 15% by mass or less with respect to the P2 layer, so that the interlayer adhesion after treatment at 120 ° C. and 100% RH for 48 hours can be improved. It is preferable from the point which can be performed. Moreover, when P2 layer contains a modified styrene-type thermoplastic elastomer, the fall of the delamination strength by wet heat processing can be suppressed. The degree to which the decrease in delamination strength due to wet heat treatment is suppressed is determined by the degree of delamination strength after wet heat treatment relative to the initial delamination strength between the P1 and P2 layers and between the P2 and P3 layers. The ratio is determined based on the ratio of decrease, and details are as described in “Characteristic Evaluation Method J. Section” in the Examples. In order to improve interlayer adhesion, it is preferably 5% by mass or more, and preferably 12% by mass or less from the viewpoint of cost. Examples of the modified styrene thermoplastic elastomer include a modified styrene-ethylene-butylene-styrene block copolymer. The modified styrene thermoplastic elastomer may be a commercially available product, for example, “Tuftec” M1913 manufactured by Asahi Kasei Chemicals Corporation.

The P3 layer in the present invention is mainly composed of a polyolefin resin. Examples of the polyolefin resin in the present invention include polyethylene, polypropylene, polybutene, polymethylpentene, polycycloolefin, polyhexene, polyoctene, polydecene, and polydodecene. Among these, polyethylene and polypropylene are preferable because they are easy to process and relatively inexpensive. These polyolefin resins may be mixed and copolymerized with other olefin components. For example, when an ethylene-propylene copolymer or an ethylene-propylene-butene copolymer is used, the crystallinity of the resin can be lowered. When applying what copolymerized polypropylene and the other olefin component as polyolefin resin, it is preferable from a viewpoint of making curl small that the polyolefin resin which comprises P3 layer contains 70 mass% or more of propylene components.

In the present invention, when a mixture of a plurality of polyolefin resins is used as the polyolefin resin constituting the P3 layer, it is preferable to contain a polyethylene resin as a constituent component in the range of 5% by mass to 30% by mass. Since the polyethylene resin does not contain tertiary carbon, it is less likely to be oxidized than polypropylene resin, and has high durability against deterioration due to oxidation. The component mentioned here is mixed in the P3 layer and is distinguished from the copolymerized component. If the content is less than 5% by mass, the improvement effect is low. In addition, mixing of incompatible olefins such as polypropylene and polyethylene may reduce brittleness due to poor dispersion. Since the decrease in brittleness may decrease the adhesion with the sealing material, it is preferable to include a compatibilizer for the P3 layer. For example, in a combination of polypropylene and polyethylene, an ethylene-ethylene / butylene / ethylene copolymer is preferably used as a compatibilizing agent, and “Dynalon” 6200P manufactured by JSR Corporation is an example of a commercially available product. The compatibilizing agent is preferably contained in the range of 0.1% by mass to 10% by mass. If it is 0.1% by mass or less, the compatibility effect is low, and if it is 10% by mass or more, the adhesion with the sealant may be lowered.

Also, as the polyolefin resin constituting the P3 layer, polyolefin elastomer may be used as the polyolefin resin that can be used when a mixture of a plurality of polyolefin resins is used. Polyolefin elastomers are those obtained by copolymerizing polypropylene and polyethylene with other α-olefins. Preferred α-olefins are 1-butene, 1-pentene, 1-hexene, 1-heptene, 1- Examples include octene, 1-nonene, 1-decene, 1-dodecene and 4-methyl-1-pentene. These polyolefin-based elastomers are preferably contained in a proportion of 5% by mass or more and 50% by mass or less with respect to the P3 layer. By including a polyolefin-based elastomer, in addition to the improvement in interlayer adhesion after treatment at 120 ° C. and 100% RH for 48 hours, the rigidity of the P3 layer is reduced, so that the curling of the laminated sheet is improved, which is preferable. Moreover, when P3 layer contains polyolefin-type elastomer, it is preferable also from a viewpoint which can suppress the fall of the delamination strength by wet heat processing. Preferably, it is 10 mass% or more and 30 mass% or less. The polyolefin-based elastomer may be a commercially available product, for example, “Thermo Run”, “Zeras” manufactured by Mitsubishi Chemical Corporation, “Excellen”, “Tough Selenium”, “Esplen”, “Hibler” manufactured by Kuraray, Preferred examples include “Septon”, “Notio” manufactured by Mitsui Chemicals, Inc., “ENGAGE” manufactured by Dow Chemical Co., Ltd., and the like.

The crystal melting energy of the P3 layer is preferably 80 J / g or less. Setting the crystal melting energy within this range is preferable from the viewpoint of reducing curling and improving the adhesion to the sealing material. More preferably, it is 70 J / g or less, More preferably, it is 60 J / g or less. Here, the crystal melting energy refers to the differential scanning calorimeter “Robot DSC-RDC220” manufactured by Seiko Denshi Kogyo Co., Ltd. according to JIS-K7122 (1987 version), and the disk session “SSC / 5200” for data analysis. This is a value obtained from the second run measured using, and the details are as described in “Characteristic Evaluation Method C. Item” in the Examples. The crystal melting energy can be adjusted by copolymerizing other olefin components in the olefin molecular chain or by the stereoregularity of the olefin crystal form. The stereoregularity can be adjusted by a catalyst during polymerization. As an example of the copolymer component, α-olefin is preferable as described above, and ethylene-propylene copolymer and ethylene-propylene-butene copolymer are particularly preferable. In addition, the stereoregularity of the olefin is preferably atactic. The lower limit of the crystal melting energy is not particularly limited, but most of them are 10 J / g or more when a polyolefin resin is the main component.

The melting endothermic peak temperature of the P3 layer in the present invention is preferably 100 ° C. or higher and 150 ° C. or lower. If it is less than 100 ° C, the heat resistance may be inferior. On the other hand, if it exceeds 150 ° C., the adhesiveness to the sealing material may be lowered.

In the case where the P3 layer has a phase separation structure and exhibits a melting endothermic peak temperature, all of them are preferably 100 ° C. or higher and 150 ° C. or lower. In such a case, the crystal melting energy is The sum of the peaks is preferably 80 J / g or less.

The melt flow rate (MFR) (230 ° C.) of the polyolefin resin is preferably from 0.5 to 30. If it is less than 0.5 or more than 30, the fluidity is low, and stacking unevenness or flow marks may occur.

In the present invention, it is preferable that the polycarbonate resin is contained in the range of 5% by mass to 25% by mass with respect to the P3 layer. By including the polycarbonate-based resin within this range, it is possible to minimize a decrease in gas barrier properties and improve flame retardancy and curl characteristics. If it is less than 5% by mass, the effect of improving the flame retardancy is low, and if it exceeds 25% by mass, the gas barrier property and the adhesion to the sealing material may be inferior. Here, the gas barrier property refers to the water vapor permeability obtained by measuring according to the method prescribed in Appendix B of “Water vapor permeability test method for plastic films and sheets (instrument measurement method)” JIS-K7129 (1992 edition). The details are as described in “Characteristic Evaluation Method I. Item” in the Examples. The flame retardancy is a burning rate of the sheet when the sheet is ignited, and details are as described in “Characteristic Evaluation Method G. Item” in the Examples. In view of the adhesion to the sealing material, it is preferably 15% by mass or less.

The P3 layer constituting the laminated sheet of the present invention preferably contains inorganic particles in the range of 1% by mass to 30% by mass with respect to the P3 layer. More preferably, they are 2 mass% or more and 20 mass% or less, More preferably, they are 3 mass% or more and 10 mass% or less. The inorganic particles are used for imparting a necessary function to the film according to the purpose. In the present invention, in view of the fact that it is often used outdoors, when inorganic oxides having ultraviolet absorbing ability use metal oxides such as titanium oxide, zinc oxide, and cerium oxide, they are resistant to ultraviolet rays caused by the particles. By taking advantage of the properties, it is possible to exhibit the effect of reducing coloring due to deterioration of the sheet over a long period of time. 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.

It is preferable that the P3 layer constituting the laminated sheet of the present invention contains organic particles in the range of 0.1% by mass to 20% by mass with respect to the P3 layer. 0.5 mass% or more is preferable from a viewpoint of concealability and design property, and 12 mass% or less is preferable from a viewpoint of the thickening suppression at the time of the melt extrusion resulting from an organic particle. More preferably, it is 1 mass% or more and 8 mass% or less. Examples of the organic particles include silicone compounds, crosslinked particles such as crosslinked styrene, crosslinked acryl, and crosslinked melamine, and carbon compounds such as carbon, fullerene, carbon fiber, and carbon nanotube. Further, when carbon is used as the organic particles in the P3 layer, it is particularly preferable because design properties and ultraviolet resistance can be simultaneously imparted.

In the present invention, when the thickness of the P1 layer is T1, the thickness of the P2 layer is T2, and the thickness of the P3 layer is T3, the expressions (1) and (2) must be satisfied.
T1 / T3 ≧ 0.5 (1)
T2 ≧ 12 μm (2)
By satisfying the expressions (1) and (2) at the same time, curling of the entire sheet can be suppressed. Here, curl is a total value of the height at which the four corners of the sheet float from the plane when the laminated sheet having a thickness of 27 μm or more is cut into a 100 mm square and the cut sheet is placed on a flat surface in an unweighted state. The details are as described in “Characteristic Evaluation Method D. Item” in the Examples. In the laminated structure of the polycarbonate-based resin and the polyolefin-based resin in the present invention, a curl is generated in which at least three corners of the sheet are lifted from the plane so that the polyolefin side (P3 layer) is the inside. When the lamination ratio of the polycarbonate resin is increased, the rigidity of the sheet is increased and the curl is reduced. Therefore, in the formula (1), as T1 / T3 is larger, the curl tends to be improved, but the gas barrier property may be lowered by decreasing the ratio of the olefin layer in the laminated sheet. For this reason, T1 / T3 is preferably 15 or less. More preferably, it is 10 or less, More preferably, it is 5 or less, Most preferably, it is 2 or less. On the other hand, when T1 / T3 is less than 0.5, the lamination ratio of polyolefin is too large, and the curl becomes large regardless of the thickness of T2. In view of both gas barrier properties and curl, T1 / T3 is preferably 0.6 or more, and most preferably 0.7 or more.

In the formula (2), curling occurs when T2 is less than 12 μm. Curling can be reduced by satisfying this range. Furthermore, satisfying the formula (2) also has an effect of improving interlayer adhesion after treatment at 120 ° C. and 100% RH for 48 hours, and further has an effect of suppressing a decrease in delamination strength due to wet heat treatment. The degree to which the decrease in the delamination strength due to the wet heat treatment is suppressed is determined by the delamination strength after the wet heat treatment relative to the initial delamination strength between the P1 layer and the P2 layer and between the P2 layer and the P3 layer. Judgment is made based on the ratio of the degree of decrease, and details are as described in “Characteristic Evaluation Method J. Section” in the Examples. The upper limit of the thickness T2 of the P2 layer is not particularly limited, but is preferably 100 μm or less for reasons such as production speed. Furthermore, if considering the curling characteristics, delamination strength, production speed, etc., the thickness of the P2 layer is preferably 5% or more and 20% or less, and 15 μm or more and 60 μm or less with respect to the total thickness of the laminated sheet. Is preferred. More preferably, it is 20 μm or more and 40 μm or less. Here, the delamination strength refers to the strength when peeling with the T-type measured according to JIS-K6854-3 (1999 edition). In view of use outdoors such as a solar cell backsheet, the initial delamination strength and the delamination strength after 120 ° C. and 100% RH 48 hr wet heat treatment are both preferably 3 N / 15 mm or more. More preferably, both are 5 N / 15 mm or more, More preferably, both are 8 N / 15 mm or more, Most preferably, both are 10 N / 15 mm or more. The initial delamination strength is determined by the interaction between the release interface resins in addition to the thickness of T2, and the resin may be selected according to the required peel strength. In particular, in the case of interfacial peeling between the P1 layer and the P2 layer, the main component of the P1 layer is polycarbonate. Therefore, the resin constituting the P2 layer should have a high acid value, or a polar functional group should be introduced into the resin. Etc. are effective. Further, the delamination strength after the wet heat treatment at 120 ° C. and 100% RH for 48 hours can suppress a decrease from the initial delamination strength by including the polyolefin elastomer in the P2 layer and the P3 layer in addition to the thickness of T2.

The total thickness of the laminated sheet of the present invention is preferably 27 μm or more and 600 μm or less, more preferably 30 μm or more and 450 μm or less, and most preferably 40 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 a backsheet. When the thickness of the laminated sheet of the present invention is less than 27 μm, the flatness of the sheet may be reduced, or the P2 layer may be too thin, and the effect of improving characteristics due to the inclusion of particles may be reduced. In this case, for example, when used as a solar cell backsheet, the overall thickness of the solar cell may become too thick.

The thickness T1 of the P1 layer in the laminated sheet of the present invention is preferably 5 μm or more and 200 μm or less, and when used for a solar cell backsheet, it may be determined by a required withstand voltage. Preferably they are 30 micrometers or more and 190 micrometers or less, More preferably, they are 50 micrometers or more and 180 micrometers or less. If it is less than 5 μm, there is no self-supporting property, and if it exceeds 200 μm, the overall thickness of the solar battery cell may be too thick.

The thickness T3 of the P3 layer in the laminated sheet of the present invention is preferably 10 μm or more and 400 μm or less, and when used for a solar cell backsheet, it may be determined by the required water vapor permeability and withstand voltage. Preferably they are 10 micrometers or more and 250 micrometers or less, More preferably, they are 30 micrometers or more and 200 micrometers or less. When the thickness is less than 10 μm, the adhesiveness with the sealing material is deteriorated, the water vapor permeability is deteriorated, and when the thickness is more than 400 μm, the entire thickness of the solar battery cell may be too thick.

The laminated structure of the laminated sheet in the present invention is at least P1 layer / P2 layer / P3 layer, and the P3 layer is provided on any one of the surface layers. By providing the P3 layer on the surface layer, the adhesion to the sealing material is improved. Moreover, when P3 layer is provided in both surface layers, although it is excellent in adhesiveness, since a polyolefin resin is made into a main structural component, a flame retardance is hard to be acquired. On the other hand, when P1 layer is provided in both surface layers, although it is excellent in a flame retardance, sufficient adhesiveness with a sealing material cannot be obtained. By providing the P3 layer only on one surface, both flame retardancy and adhesion with the sealing material can be achieved. In addition, each of the P1 layer, the P2 layer, and the P3 layer may have a laminated structure, and may have a multilayer structure according to a required function.

Also, the laminated sheet of the present invention can be laminated with other films and the like. Also in this case, the P3 layer may have a laminated structure provided on any one of the surface layers. Examples of 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 flame resistance for imparting flame resistance A layer, a hard coat layer for improving impact resistance and scratch resistance, and the like can be arbitrarily selected and used depending on applications. 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 and 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.

The laminated sheet of the present invention preferably has a Δb of 10 or less when the P1 layer is used as the incident surface from the viewpoint of ultraviolet resistance. Here, Δb is a value calculated using K0 as the b value measured with the laminated sheet P1 layer before the ultraviolet treatment as the incident surface, and K as the b value measured with the laminated sheet P1 layer after the ultraviolet treatment as the incident surface, Details are as described in “Characteristic Evaluation Method H. Item” in the Examples. Preferably it is 6 or less. More preferably, it is 3 or less. In order to set Δb to 10 or less, a preferable method is to add 10% by mass or more of inorganic particles to the P1 layer, and Δb can be reduced according to the content of inorganic particles.

From the viewpoint of gas barrier properties, the laminated sheet of the present invention preferably has a water vapor permeability of 0.0001 g / m ² · day to 10 g / m ² · day. More preferably, it is 0.0001 g / m ² · day or more and 5 g / m ² · day or less, and most preferably 0.0001 g / m ² · day or more and 3 g / m ² · day or less. By setting it as this range, deterioration inside the solar cell due to permeation of gas from the back sheet to the sealing material can be prevented. Here, the water vapor transmission rate is a value obtained by measurement according to the method prescribed in Appendix B of “Test method for water vapor transmission rate of plastic film and sheet (instrument measurement method)” JIS-K7129 (1992). Is as described in “Characteristic Evaluation Method I. Item” in the Examples. In the present invention, the water vapor transmission rate can be adjusted by the total thickness of the P2 layer thickness T2 and the P3 layer thickness T3, and the water vapor transmission rate decreases as the total thickness increases.

Next, an example is given and demonstrated about the manufacturing method of the lamination sheet of the present invention. As a method of laminating the P1, P2, and P3 layers in the laminated sheet of the present invention, for example, the P1 layer raw material, the P2 layer raw material, and the P3 layer raw material are respectively charged into three 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. Of these, the coextrusion method is preferred 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 the laminated sheet of the present invention is produced by a co-extrusion method, first, a composition for P1 layer having a polycarbonate resin as a main constituent, a composition for P2 layer, and a P3 layer having a polyolefin resin as a main constituent Are fed to separate extruders and melted respectively. At this time, it is preferable to dry the composition for each layer, and as a condition at the time of melting, the composition for the P1 layer is 240 ° C. or more and 300 ° C. or less under a nitrogen stream, and the composition for the P2 layer and It is preferable that the composition for the P3 layer is supplied to each of three extruders heated to 180 ° C. or higher and 280 ° C. or lower and melted. Next, after melting, the P1 layer, the P2 layer, and the P3 layer are joined and laminated in this order, and extruded from the T-die into a sheet shape to form a laminated sheet. At this time, it is preferable that the P1 layer, the P2 layer, and the P3 layer are joined and laminated using a multi-manifold die, a feed block, a static mixer, pinol, or the like, and co-extruded from the die. When the difference in melt viscosity is large, a multi-manifold is preferable from the viewpoint of suppressing lamination unevenness. 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.

Further, a composition obtained by mixing a resin obtained by processing the laminated sheet of the present invention into chips or flakes in a range of 5% by mass or more and 50% by mass or less with respect to the composition for P3 layer and a composition for P3 layer It is also possible to do. In this case, it is particularly preferable to use cutting loss or waste generated in the production process of the laminated sheet of the present invention as the laminated sheet to be processed into chips or flakes because loss is reduced and productivity is improved. A known method may be used as a method of processing into a chip shape or flake shape, but it is preferable to form a flake shape without melting and heating as much as possible from the viewpoint of suppressing a decrease in molecular weight and oxidation deterioration.
When the laminated sheet of the present invention is produced by the co-extrusion method, when the P1 layer is in contact with the casting drum surface, the cooling temperature at the first stage is 50 ° C. or higher, “the glass transition temperature of the polycarbonate resin—10 ° C.” The following is preferable from the viewpoint of good flatness of the obtained sheet. Moreover, it is also preferable from the viewpoint of obtaining flatness that the casting is performed by a calendar method. In this case, if the drum roll temperature in contact with the P3 layer is set to 15 ° C. or less, the volume shrinkage at the time of olefin cooling solidification is suppressed and the curling of the sheet is reduced. This is preferable. Furthermore, when winding a laminated sheet in a roll shape, it is preferable from the viewpoint of reducing the curl of the sheet when the P3 layer is wound around the outer surface.

The laminated sheet of the present invention obtained by the above-described method may be subjected to processing such as heat treatment or aging as necessary within the range where the effects of the present invention are not impaired. The upper limit of the heat treatment temperature is not more than “glass transition temperature −10 ° C.”, more preferably “glass transition temperature −30 ° C.” or less, more preferably “less than“ glass transition temperature ”of the resin constituting the P1 layer, from the planarity of the sheet. The glass transition temperature is −50 ° C. or lower. The heat treatment time is preferably 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. Moreover, in order to improve the adhesiveness of the laminated sheet of the present invention obtained by the above method, corona treatment or plasma treatment may be performed.

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 2 such as EVA resin, a transparent substrate 4 such as glass, and the laminate of the present invention. Although a sheet | seat is bonded and comprised as the solar cell backsheet 1, it is not limited to this, It can use for arbitrary structures. 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.

In the laminated sheet of the present invention, as a method of laminating with other films, etc., for example, a method of co-extrusion and processing into a sheet (co-extrusion method), a coating layer raw material is put into an extruder into a sheet made of a single film Then, melt extrusion and laminating while extruding from the die (melt laminating method), making each film separately, thermocompression bonding with heated rolls etc. (thermal laminating method), pasting through adhesive A method of bonding (adhesion method), a method of applying and drying a solution dissolved in a solvent (coating method), a method of combining these, and the like can be used.

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 2 in which the power generating element is sealed. Here, 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 P3 layer is disposed so as to be positioned on the sealing material 2 side. This is preferable in that the adhesion to the stopper can be further increased. Moreover, it is preferable to arrange | position so that P1 layer of the lamination sheet of this invention may be located at least on the opposite side to the sealing material 2. FIG. 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.

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 it satisfies the above characteristics. 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.

In addition, in order to provide these substrates with adhesion to an EVA resin or the like that is a sealing material for power generation elements, 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 generating element covers the surface of the power generating element with resin and fixes it, protects the power generating element from the external environment, and has 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, T3, stacking ratio T1 / T3
It was determined by the following procedures (A1) to (A4). In addition, the measurement is performed by changing the location at 10 locations, and the average value of the layer thickness T1 (μm) of the P1 layer, the layer thickness T2 (μm) of the P2 layer, the layer thickness T3 (μm) of the P3 layer, the lamination ratio T1 / T3.
(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. Although the observation location is determined randomly, the vertical direction of the image is parallel to the thickness direction of the laminated sheet, and the horizontal direction of the image is parallel to the surface direction of the laminated sheet. 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, the layer thickness T2 of the P2 layer, and the thickness T3 of the P3 layer in the image obtained in (A2) were determined.
(A4) T1 was divided by T3, and the lamination ratio T1 / T3 was calculated.

B. Inorganic particle content Wa1, Wa2, organic particle content Wa3, Wa4
Each of the P1 layer and the P3 layer is scraped or peeled off from the laminated sheet to separate the P1 layer and the P3 layer. About them, the inorganic particle content rate Wa1 of the P1 layer and the inorganic particle content rate Wa2 of the P3 layer are as follows. The organic particle content Wa3 of the P1 layer and the organic particle content Wa4 of the P3 layer were determined.
The mass wa1 ″ (g) of the material cut out from the P1 layer and the mass wa3 ″ (g) of the material cut out from the P3 layer were measured. Subsequently, it was made to melt | dissolve in a methylene chloride, and the inorganic particle and the organic particle were fractionated among the insoluble matters by centrifugation. The obtained inorganic particles and organic 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 wa1 ′ (g) of the obtained inorganic particles and the mass wa3 ′ of the organic particles were determined, and the inorganic particle content Wa1 and the organic particle content Wa3 were measured from the following formulas (4) and (5).
P1 layer inorganic particle content (% by mass) Wa1 = (wa1 ′ / wa1 ″) × 100 (4)
Organic particle content of P1 layer (mass%) Wa3 = (wa3 ′ / wa3 ″) × 100 (5)
Also in the P3 layer, the solvent to be dissolved was changed to ortho-dichlorobenzene (100 ° C.), and the inorganic particle content Wa2 and the organic particle content Wa4 in the P3 layer were determined in the same manner as in the P1 layer.

C. It was measured and calculated according to JIS-K7122 (1987 version) using the melting point Tm of the P3 layer and crystal melting energy differential scanning calorimetry (DSC). The P3 layer was cut out from the laminated sheet, a sample was set, and the temperature was raised from 25 ° C. to 200 ° C. at 20 ° C./min. The measurement result obtained here is a first run. Next, it was rapidly cooled to 25 ° C., and again heated from 25 ° C. to 200 ° C. at a rate of 20 ° C./min. The measurement result of the second run at this time is schematically shown in FIG. FIG. 2A is a peak top showing the melting point Tm, and FIG. 2B (area of the hatched portion), which is an integrated value from the base line, was used as the crystal melting energy.
Equipment: “Robot DSC-RDC220” manufactured by Seiko Electronics Industry Co., Ltd.
Data Analysis “Disk Session SSC / 5200”
Sample mass: 2mg
D. A laminated sheet having a curl thickness of 27 μm or more is cut into a square of 100 mm, and the cut sheet is left so as to be convex downward when curled in a state of no load and no wind on a horizontal and flat surface. The four corners are the total values of the heights above the plane, and the determination was made as follows based on these values.
When the total height of the four corners is less than 20 mm: ◎
When the total height of the four corners is 20 mm or more and less than 50 mm: ○
When the total height of the four corners is 50 mm or more and less than 100 mm: △
When the total height of the four corners is 100 mm or more: ×
～ to △ are good, among which ◎ is the best.

E. Adhesiveness to sealing material Using the strength when peeled at 180 ° measured according to JIS-K6854-2 (1994 edition), the adhesiveness of the sealing material was evaluated from the peel strength between the EVA sheet and the P3 layer. did. The test specimen is a 500 μm-thick EVA sheet manufactured by Sanvic Co., Ltd., and a laminated sheet of Examples and Comparative Examples subjected to corona treatment on a semi-tempered glass having a thickness of 3 mm, and a commercially available glass laminator is used. After depressurization, a product subjected to press treatment at 143 ° C. under a load of 29.4 N / cm ² for 15 minutes was used. The width of the test piece for the peel strength test was 10 mm, two test pieces were prepared, and each test piece was measured at three locations with different locations, and the average value of the obtained measured values was taken as the peel strength value.
From the obtained peel strength, the adhesiveness of the sealing material was determined as follows.
When peel strength is 50 N / 10 mm or more: S
When the peel strength is 40 N / 10 mm or more and less than 50 N / 10 mm: A
When peel strength is 30N / 10mm or more and less than 40N / 10mm: B
When the peel strength is 20 N / 10 mm or more and less than 30 N / 10 mm: C
When peel strength is less than 20 N / 10 mm: D
S to C are good, and S is the best among them.

F. Interlayer adhesion after wet heat treatment Adhesion was evaluated from the delamination strength after wet heat treatment. As the delamination strength, the strength at the time of peeling with a T-type measured according to JIS-K6854-3 (1994 edition) was used. Here, the interlayer may be an interlayer capable of interfacial separation such as between the P1 layer and the P2 layer and between the P2 layer and the P3 layer. The width of the test piece for the peel strength test is 15 mm, and two test pieces are prepared. The test piece is changed in place and measured at three points, and the average value of the obtained measured values is the delamination strength after the wet heat treatment. As described below, the interlayer adhesion after the wet heat treatment was determined. Moreover, it processed for 48 hours on the conditions of temperature 120 degreeC and 100% RH in the pressure cooker by Tabay Espec Co., Ltd. as wet heat treatment conditions.
When peel strength is 10N / 15mm or more: S
When the peel strength is 6 N / 15 mm or more and less than 10 N / 15 mm: A
When peel strength is 3N / 15mm or more and less than 6N / 15mm: B
When peel strength is 1N / 15mm or more and less than 3N / 15mm: C
When peel strength is less than 1 N / 15 mm: D
S to C are good, and S is the best among them.

G. Flame retardance Based on the UL94HB test, the sheet was cut into a size of 13 mm x 125 mm, and the first marked line was drawn at 25.4 mm from the cut end in the longitudinal direction, and the second marked line was drawn at 101.6 mm. The burning rate from the first marked line to the second marked line when the combustion test was performed while being held horizontally was performed at N = 3 in the width direction and the longitudinal direction of the sheet, and the average value was obtained. The obtained burning rate was determined as follows.
When the burning rate is less than 100 mm / min: A
When the burning rate is 100 mm / min or more and less than 110 mm / min: B
When the burning rate is 110 mm / min or more and less than 130 mm / min: C
When the burning rate is 130 mm / min or more and less than 150 mm / min: D
When the burning rate is 150 mm / min or more: E
As for flame retardancy, A to D are good, and A is the best among them.

H. UV resistance When the b value measured from the laminated sheet P1 layer side before the ultraviolet ray treatment is K0, and the b value measured from the laminated sheet P1 layer side after the ultraviolet ray treatment is K, the value obtained by the following equation (3) is The UV resistance of the laminated sheet was evaluated from this value as Δb on the P1 layer side.
Δb = K−K0 (3) The ultraviolet ray treatment is performed using a xenon weather meter SC750 manufactured by Suga Test Instruments Co., Ltd., at a temperature of 65 ° C., a relative humidity of 50% RH, and an intensity of 150 mW / cm ² (light source: xenon lamp). , Wavelength range: 290 to 400 nm), the P1 layer side was irradiated for 1000 hours. The method for obtaining the b value is as follows.
Using a spectroscopic color difference meter SE-2000 (manufactured by Nippon Denshoku Industries Co., Ltd.), the b value of the P1 layer was measured in the reflection mode according to JIS-Z8722 (2000 version). The number of samples was n = 5, the sample measurement diameter was 30 mmφ, each b value was measured, and the average value was calculated. From the obtained Δb on the P1 layer side, the ultraviolet resistance of the laminated sheet was determined as follows.
When the color change Δb is less than 3: S
When the color change Δb is 3 or more and less than 6: A
When the color change Δb is 6 or more and 10 or less: B
When color change Δb exceeds 10: C
S to B are good, and S is the best among them.

I. Gas barrier property Using PERMATRAN W-TWIN manufactured by MOCON, according to the method prescribed in Appendix B of “Test method for water vapor permeability of plastic films and sheets (instrument measurement method)” JIS-K7129 (1992 version), Measurements were performed under 90% RH conditions. The gas barrier property of the laminated sheet was determined from the obtained water vapor permeability as follows.
When the water vapor transmission rate is less than 3 g / m ² · day: S
When the water vapor transmission rate is 3 g / m ² · day or more and less than 5 g / m ² · day: A
When the water vapor transmission rate is 5 g / m ² · day or more and 10 g / m ² · day or less: B
When the water vapor permeability exceeds 10 g / m ² · day: C
S to B are good, and S is the best among them.

J. et al. Depression suppression degree of delamination strength due to wet heat treatment Depression suppression degree of delamination strength due to wet heat treatment was calculated from the following formula (6) when the initial delamination strength was G ⁰ and delamination strength G ¹ after wet heat treatment. Judgment is made from the delamination strength reduction ratio after the wet heat treatment.
Ratio of reduction in delamination strength after wet heat treatment = G ¹ / G ⁰ (6)
Here, as the delamination strength, the strength at the time of peeling with the T type measured according to JIS-K6854-3 (1994 edition) was used. The interlayer may be an interlayer capable of interfacial separation such as between the P1 layer and the P2 layer and between the P2 layer and the P3 layer. The width of the test piece for the peel strength test was 15 mm, two test pieces were prepared, and each test piece was measured at three locations by changing the location. The average value of the obtained measured values was taken as the delamination strength. Further, as a wet heat treatment condition, a pressure cooker manufactured by Tabai Espec Co., Ltd. was used for 48 hours under the conditions of a temperature of 120 ° C. and 100% RH. From the value calculated from the equation (6), the degree of suppression of decrease in delamination strength due to wet heat treatment was determined as follows.
When the delamination strength reduction ratio after wet heat treatment is 1.0 or more: S
When delamination strength reduction ratio after wet heat treatment is 0.7 or more and less than 1.0: A
When the delamination strength reduction ratio after wet heat treatment is 0.5 or more and less than 0.7: B
When the delamination strength reduction ratio after wet heat treatment is 0.3 or more and less than 0.5: C
When the delamination strength reduction ratio after wet heat treatment is less than 0.3: D
S to B are good, and S is the best among them.

[material]
-Polycarbonate-type resin The following were used as polycarbonate-type resin which comprises P1 layer.
(PC1) "Taflon" A2200 manufactured by Idemitsu Kosan Co., Ltd.
Used in Examples 1-35, 37-80 and Comparative Examples 1-4.
(PC2) "Taflon" A1700 manufactured by Idemitsu Kosan Co., Ltd.
Used in Example 36 and Examples 81-101.

-Adhesive layer resin The following were used as adhesive layer resin which comprises P2 layer.
(Adhesive Resin 1) “Modic” F534A manufactured by Mitsubishi Chemical Corporation, acid-modified polyolefin Used in Examples 1-36, 40-80, and Comparative Examples 1-4.
(Adhesive resin 2) “Modic” F532 manufactured by Mitsubishi Chemical Corporation, acid-modified polyolefin Used in Example 37.
(Adhesive Resin 3) “Modic” P553A manufactured by Mitsubishi Chemical Corporation, acid-modified polyolefin Used in Example 38.
(Adhesive Resin 4) “Admer” SF731, manufactured by Mitsui Chemicals, Inc., acid-modified polyolefin Used in Example 39.
(Adhesive resin 5) “Modic” F535 manufactured by Mitsubishi Chemical Corporation, acid-modified polyolefin Used in Examples 81 to 101.

-Polyolefin resin The following were used as polyolefin resin.
(LLDPE1) "Sumikasen L" GA401 manufactured by Sumitomo Chemical Co., Ltd.
Used in Examples 1 to 7 and Examples 81 to 101.
(PP1) Prime Polymer Co., Ltd. “Prime Polypro” E100GV
Used in Examples 8-14.
(PP2) "Prime Polypro" F704NP manufactured by Prime Polymer
Used in Examples 15-21 and Comparative Examples 1-4.
(PP3) Prime Polymer Co., Ltd. “Prime Polypro” F744NP (ethylene content 4.2 mass%)
Used in Examples 22-28.
(EPBC1) "Noblen" FL6745A manufactured by Sumitomo Chemical Co., Ltd.
Used in Examples 29-80.
(EPC1) "Nobren" FL6412 manufactured by Sumitomo Chemical Co., Ltd.
Used in Examples 81-101.

-Polyolefin elastomers The following were used as polyolefin elastomers.
(Elastomer 1) “Notio” PN2060 manufactured by Mitsui Chemicals, Inc.
Used for P3 layer of Examples 14, 21, 28, 35, 53, and P2 layer of Examples 60, 76.
(Elastomer 2) “ENGAGE” 8200 manufactured by Dow Chemical Co., Ltd.
Examples 50 to 52, 54, 55, 59, 63 to 72, 79,
80 P3 layers, and
Used for P1 layer of Examples 56 to 59, 61, 62, 73 to 75, 77, 78.

-Modified styrene thermoplastic elastomer The following were used as a modified styrene thermoplastic elastomer.
(M-SEBS) "Tough Tech" M1913 manufactured by Asahi Kasei Chemicals
Used in Examples 84-87, 91-94, 98-101.

-Compatibilizer The following were used as a compatibilizer applied to the P3 layer.
(Dynalon) “Dynalon” 6200P manufactured by JSR Corporation
Used in Examples 83-87, 90-94, 97-101.

Inorganic particles Rutile type titanium dioxide was used as inorganic particles. In each Example etc., the following mastered resin was used so that it might become a mixing ratio of a table | surface description.
(MB2) Resin obtained by mastering PC2 and titanium dioxide at a ratio of 50% by mass / 50% by mass Reference Example 2, Examples 6 to 39, 42, 43, 68 to 78,
Used for P1 layer of 88-94 and Comparative Examples 1-4.
(MB5) Resin in which EPC1 and titanium dioxide were mastered at a ratio of 30% by mass / 70% by mass Reference Examples 1, 2, Examples 12, 13, 19, 20, 26,
Used for P3 layer of 27, 81-94.
(MB6) Resin in which EPBC1 and titanium dioxide were mastered at a ratio of 30% by mass / 70% by mass Used for P3 layer of Examples 33, 34, 36 to 42, 44 to 62, 68 to 78.

-Organic particles Carbon black was used as organic particles. In each Example etc., the following mastered resin was used so that it might become a mixing ratio of a table | surface description.
(MB1) Resin in which PC2 and carbon black are mastered at a ratio of 90% by mass / 10% by mass Reference Examples 1, 3, Examples 40, 41, 44 to 47, 50 to 67,
Used for 79-87 and 95-101 P1 layers.
(MB4) Resin obtained by mastering EPC1 and carbon black at a ratio of 90% by mass / 10% by mass Used for P3 layer in Reference Example 3, Examples 63 to 67, 95 to 101.
(MB7) Resin obtained by mastering PC2 and carbon black at a ratio of 80% by mass / 20% by mass Used for the P1 layer of Examples 48 and 49.

-Ultraviolet absorber "TINUVIN329" by BASF Japan Ltd. was used as an ultraviolet absorber. In each Example etc., the following mastered resin was used so that it might become a mixing ratio of a table | surface description.
(MB3) Resin in which PC2 and “TINUVIN329” were mastered at a ratio of 90% by mass / 10% by mass Used in Examples 81-101.

・ Resin processed into flakes from laminated sheets The following resin was processed into flakes for cutting loss and edge parts (hereinafter simply referred to as “laminated sheets”) of the laminated sheets obtained in Reference Examples 1 to 3. Using.
(Flake 1) A resin in which the laminated sheet obtained in Reference Example 1 is made into flakes.
(Flake 2) A resin obtained by making the laminated sheet obtained in Reference Example 2 into a flake shape.
(Flake 3) A resin in which the laminated sheet obtained in Reference Example 3 is made into flakes.

(Reference Examples 1 to 3)
With the extruder 1 as the P1 layer, the extruder 2 as the P2 layer, and the extruder 3 as the P3 layer, the resins shown in Table 2-1 were melted in each extruder at the extrusion temperatures shown in Table 2-2. Next, the layers melt-extruded from each extruder are joined together in a multi-manifold die so that the layers P1 layer / P2 layer / P3 layer are laminated in order, and the resin discharged from the die is placed on a cast drum having a surface temperature of 10 ° C. Then, it was cooled and solidified so that the P3 layer side was in contact with the cast drum surface to obtain a laminated sheet.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not necessarily limited thereto.

(Examples 1 to 101, Comparative Examples 1 and 2)
Using the extruder 1, the extruder 2 and the extruder 3, the resin was put into each extruder at the resin mixing ratio shown in Table 1 for each layer and melted at the extrusion temperature shown in Table 1. Next, the layers melt-extruded from the extruder 1 are the P1 layer, the extruder 2 is the P2 layer, the extruder 3 is the P3 layer, and the layers are joined together in the order of P1 layer / P2 layer / P3 layer. The resin discharged from the die was cooled and solidified on the cast drum to obtain a laminated sheet. The P1 layer, P2 layer, and P3 layer had thicknesses and lamination ratios shown in Table 1. The P1 layer PC and the resin mastered with PC were those dried at 110 ° C. for 6 hours.
The obtained laminated sheet was evaluated for flame retardancy, curl characteristics, and adhesion to a sealing material. As a result, as shown in Table 1, it was found that the examples were laminated sheets excellent in flame retardancy and curl characteristics.
Further, Examples 6 to 39, 42, 43, and 68 to 78 had excellent ultraviolet resistance because the P1 layer contained titanium dioxide as inorganic particles. In Examples 12, 13, 19, 20, 26, 27, 33, 34, and 36 to 39, the P3 layer also contained titanium dioxide as inorganic particles, and thus was further excellent in UV resistance.
Further, Examples 1 to 7 and 22 to 80 had excellent adhesion to the sealing material because the melting point of the P3 layer was about 130 ° C.
Further, since the P3 layer of Examples 14, 21, 28, 35, 50 to 55, 59, 63 to 72, 79, 80, and the P2 layer of Examples 56 to 62, 73 to 78 contained polyolefin elastomer. It was excellent in curling, adhesion to a sealing material, and suppression of a decrease in delamination strength after wet heat treatment.
Furthermore, the polyolefin elastomer was contained in the P3 layer of Examples 14, 21, 28, 35, 50 to 55, 59, 63 to 72, 79, 80 and the P2 layer of Examples 56 to 62, 73 to 78. In addition, the degree of suppression of decrease in delamination strength was excellent. In particular, Example 59 included polyolefin elastomer in both P2 and P3 layers, and Examples 62 and 78 included 50% by mass of polyolefin elastomer in P2 layer. Excellent suppression.
Further, in Examples 14 and 21 to 80, since the crystal melting energy of the P3 layer was 80 J / g or less, the curl characteristics and the adhesion to the sealing material were excellent.
Further, the P1 layer of Examples 40, 41, 44 to 67, 79, and 80 and the P3 layer of Examples 63 to 67 contained carbon black as organic particles, and thus were excellent in ultraviolet resistance and design.
On the other hand, Comparative Example 1 was inferior in curl characteristics because the thickness of the P2 layer was less than 12 μm.
Since Comparative Example 2 had T1 / T3 of less than 0.5, the curl characteristics were inferior.

Furthermore, since the P1 layers of Examples 82 to 87, 89 to 94, and 96 to 101 contained an ultraviolet absorber, they were more excellent in UV resistance.

Furthermore, since the P2 layers of Examples 84 to 87, 91 to 94, and 98 to 101 contained a modified styrene elastomer, they were excellent in the degree of suppressing the decrease in delamination strength.

Furthermore, Examples 85 to 87, 92 to 94, and 99 to 101 were more excellent in flame retardancy and curl characteristics because the P3 layer contained a polycarbonate resin. Moreover, since the loss generated during the production of the laminated sheet was reused, the yield was improved and the productivity was excellent.

(Comparative Example 3)
Using the extruder 1, the extruder 2 and the extruder 3, the resins shown in Table 1 were melted at the extrusion temperature shown in Table 1. Next, the layer melt-extruded from the extruder 1 is the P1 layer, the extruder 2 is the P2 layer, the extruder 3 is the P3 layer, and the layers are laminated in the order of P1 layer / P2 layer / P3 layer / P2 layer / P1 layer. The layers were joined at the manifold, and the resin discharged from the die was cooled and solidified on the cast drum to obtain a laminated sheet. The P1 layer, P2 layer, and P3 layer had thicknesses and lamination ratios shown in Table 1. The P1 layer PC used was dried at 110 ° C. for 6 hours.
The obtained laminated sheet was evaluated for flame retardancy and curl characteristics. As a result, as shown in Table 1, since the P3 layer was not provided on at least one surface layer, the adhesion with the sealing material was inferior.

(Comparative Example 4)
Using the extruder 1, the extruder 2 and the extruder 3, the resins shown in Table 1 were melted at the extrusion temperature shown in Table 1. Next, the layer melt-extruded from the extruder 1 is the P1 layer, the extruder 2 is the P2 layer, the extruder 3 is the P3 layer, and the layers are laminated in the order of P3 layer / P2 layer / P1 layer / P2 layer / P3 layer. The layers were joined at the manifold, and the resin discharged from the die was cooled and solidified on the cast drum to obtain a laminated sheet. The P1 layer, P2 layer, and P3 layer had thicknesses and lamination ratios shown in Table 1. The P1 layer PC used was dried at 110 ° C. for 6 hours.
The obtained laminated sheet was evaluated for flame retardancy and curl characteristics. As a result, as shown in Table 1, since the P3 layers were provided on both surface layers, the flame retardancy was poor.

The laminated sheet of the present invention can provide a laminated sheet having excellent compatibility between flame retardancy and curl characteristics as compared with conventional laminated sheets of polycarbonate resin and polyolefin resin. 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.

1: Back sheet for solar cell 2: Sealing material 3: Power generation element 4: Transparent substrate 5: Surface on the sealing material 2 side of the back sheet for solar cell 6: Side opposite to the sealing material 2 of the back sheet for solar cell Surface a: melting endothermic peak temperature b: crystal melting energy

Claims

A laminated sheet having a layer (P1 layer) mainly composed of a polycarbonate-based resin, an adhesive layer (P2 layer), and a layer (P3 layer) mainly composed of a polyolefin-based resin, A laminated sheet having a laminated structure in which the surface layer is a P3 layer, wherein the thickness of the P1 layer is T1, the thickness of the P2 layer is T2, and the thickness of the P3 layer is T3, and satisfies the following formulas (1) and (2).
T1 / T3 ≧ 0.5 (1)
T2 ≧ 12 μm (2)
The laminated sheet according to claim 1, wherein the polyolefin-based resin constituting the P3 layer contains a polyethylene resin as a constituent component in a range of 5% by mass to 30% by mass.
The laminated sheet according to claim 1 or 2, wherein the P2 layer contains 3% by mass or more and 15% by mass or less of the modified styrene thermoplastic elastomer.
The laminated sheet according to any one of claims 1 to 3, wherein the crystal melting energy of the P3 layer is 80 J / g or less.
The laminated sheet according to any one of claims 1 to 4, wherein the P1 layer contains 3% by mass or more and less than 50% by mass of inorganic particles.
The laminated sheet according to any one of claims 1 to 5, wherein the P1 layer contains 0.1% by mass or more and 20% by mass or less of organic particles.
The laminated sheet according to any one of claims 1 to 6, wherein the P3 layer contains 5 mass% or more and 50 mass% or less of a polyolefin-based elastomer.
The laminated sheet according to any one of claims 1 to 7, wherein the P3 layer contains 1% by mass to 30% by mass of inorganic particles.
The laminated sheet according to any one of claims 1 to 8, wherein the P2 layer comprises acid-modified polyolefin as a main constituent.
The laminated sheet according to any one of claims 1 to 9, wherein the P2 layer contains 5 to 50% by mass of a polyolefin-based elastomer.
The laminated sheet according to any one of claims 1 to 10, comprising a polycarbonate-based resin in a range of 5% by mass to 25% by mass with respect to the P3 layer.
A solar cell backsheet using the laminated sheet according to any one of claims 1 to 11.
The solar cell using the solar cell backsheet of Claim 12.
The method for producing a laminated sheet according to any one of claims 1 to 11, comprising a composition for P1 layer, a composition for P2 layer, and a polyolefin resin mainly comprising a polycarbonate resin. Supplying the composition for the P3 layer as a constituent component to different extruders, respectively, melting each P1 layer, P2 layer, P3 layer in this order and laminating them, and extruding them from the T die into a sheet The manufacturing method of the laminated sheet containing.
A composition obtained by mixing a resin obtained by processing the laminated sheet according to any one of claims 1 to 11 into chips or flakes in a range of 5% by mass or more and 50% by mass or less with respect to the composition for the P3 layer. The manufacturing method of the lamination sheet of Claim 14 used as a composition for layers.
As a composition for the P2 layer, a resin mainly composed of acid-modified polyolefin is mixed in a proportion of 50% by mass to 95% by mass and a polyolefin elastomer is mixed in a proportion of 5% by mass to 50% by mass and supplied to the extruder. The manufacturing method of the lamination sheet of Claim 14 or Claim 15 to do.
As a composition for the P3 layer, a resin mainly composed of a polyolefin resin is mixed in a proportion of 50 to 95% by mass and a polyolefin elastomer is mixed in a proportion of 5 to 50% by mass and supplied to an extruder. The method for producing a laminated sheet according to any one of claims 14 to 16.