SEAL. FILM FOR SOLAR CELL MODULE AND SOLAR CELL MODULE UTILIZING THE SAME TECHNICAL FIELD [0001] The present invention relates to a seal film for solar cell module having a gas barrier layer and, also relates to a solar cell module using the seal film. [0002] More specifically, the present invention relates to a seal film for solar cell module excellent in long-term "^V reliability with a significantly improved weather resistance such as hydrolysis resistance and ultra-violet resistance, resulting from a marlcedly improved durability of a gas barrier layer and also relates to a solar cell module using the seal film. BACKGROUND ART [3] In recent years, a solar cell has attracted attention as a next generation energy source and has widely been used in residential and industrial applications. [4] A demand for a solar cell with a longer life of 20 to 30 years (long-term use reliability) is particularly increased with the growing popularization of the solar cell. [5] Requests for the long-term reliability (long-term durability) of a gas barrier layer provided to block water and oxygen, for the prevention of deterioration of the seal film by hydrolysis as well as the provision of characteristics such as ultra-violet resistance to the seal film, and the like, and further for total improvement in weather resistance with these characteristics combined together have been increased day by day. [0006] The seal film for solar cell module also needs to be excellent in processability and to have mechanical properties (toughness and the like) for protecting internal solar cell and for withstanding long-term use. [7] In addition, chemical-resistance to withstand a harsh environment where various kinds of gases are generated such as those in a hot spring area, a sewage facility and the like has been demanded for the seal film. Also, the achievement of electrical insulation and reduced weight which are the basic characteristics of the seal film for solar cell module is of course desired. [8] Conventionally-known seal films for solar cell module generally include ones described in the following items (1) to (6) . (1) A seal film formed of a base material of a fluorine resin sheet and/or a polyethylene terephthalate film (hereinafter sometimes abbreviated to a PET film) and a several tens um thick aluminum foil provided on the base material film as a gas barrier layer is commercially available. (2) A seal film formed of a weather resistant film such as a fluorine resin sheet or the like and a vapor-deposited layer made of a transparent inorganic compound is proposed to improve weather resistance (refer to for example Patent Document 1). (3) A seal film having a l3ir.inated construction with a metal oxide-deposited layer/a white resin film layer is proposed to achieve a laminated construction in which a hydrolysis resistant PET film and a gas barrier film are stacked {refer to for example Patent Document 2). (4) A seal film formed of a PET film and a gas barrier layer and improved in hydrolysis resistance, weather resistance and reflection efficiency is proposed (refer to for example Patent Document 3). (5) For use in a harsh environment such as that of a volcano, a hot spring, and a water or sewer treatment facility, a solar cell module provided with a poly-p-phenylene sulfide (hereinafter sometimes abbreviated to PPS) layer as a gas resistant layer in the outermost layer of a seal film for solar cell module (refer to for example Patent Document 4) and a solar cell module provided with a PPS layer as a gas barrier layer (refer to for example Patent Document 5) are proposed. (6) It is known that a biaxially oriented PPS film is used as an electrical insulator having heat resistance because of its excellent heat resistance and hydrolysis resistance (moisture and heat resistance) (refer to for example Patent Document 6) . [9] However, the conventional seal films described above in items (1) to (6) have some of the following problems and accordingly have not sufficiently widely been applied to a seal film for solar cell module. For example, the seal film described above in item (1) using an aluminum foil as the gas barrier layer is excellent in gas barrier properties but questionable in electrical insulation and v/eight red-action. [0011] In addition, the seal film described above in item (2) is excellent in weather resistance and hydrolysis resistance and has a small fluctuation in gas barrier properties because the seal film uses a fluorine-based film as the base. However, the seal film has a low effect of increasing the mechanical strength of the solar cell module, possibly resulting in a broken solar cell element because of a low mechanical strength (low stiffness) of the fluorine-based film. Also, the seal film is inferior in processability, for example, in bonding. [0012] In the seal films described above in items (3) and (4), the deterioration of the film due to hydrolysis can be prevented because of the use of a hydrolysis resistant PET film. The films, however, have a problem that gas barrier properties deteriorate by long-term use, thereby resulting in a tendency for the reduction in the output of the solar cell module to occur. In addition, the films have another problem that the deterioration of the seal film proceeds in a short time due to the deteriorations by heat resistance, hydrolysis and generated toxic gas in an atmosphere including a high temperature, a high humidity, a specific toxic gas and the lilce in a hot spring area, a sewer treatment facility and the like, resulting in rapid reduction in the life of the solar cell module. [0013] The seal film described above in item (5) has an effect of preventing the deterioration of the seal film in an external environment in an atmosphere including a high temperature, a high hiimidity, a chemical, a generated toxic gas and the like because a biaxially oriented PPS film is stacked in the outermost layer of the seal film. However, the gas barrier properties of the gas barrier layer deteriorate by long-term use as similar to the seal film described above in items (3) and (4), thereby resulting in the reduction in the output of the solar cell module. Accordingly, the seal film cannot achieve a reliability of enabling a longer life of 20 to 30 years . [14] Patent Document 1: Japanese Patent Application Kokai Publication No. 2000-138387 Patent Document 2: Japanese Patent Application Kokai Publication No. 2002-100788 Patent Document 3: Japanese Patent Application Kokai Publication No. 2002-26354 Patent Document 4: Japanese Patent Application Kokai Publication No. 2003-31824 Patent Document 5: Japanese Patent Application Kokai Publication No. 2005-86104 Patent Document 6: Japanese Patent Application Kokai Publication No. Sho 55-3 5459 DISCLOSURE OF INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION [15] In consideration of the foregoing problems, an object of the present invention is to provide a seal film which solves a problem of the deterioration of the seal film due to external environment, and also to provide a solar cell module using the seal film. In the seal film, prevention of the gas barrier property deterioration due to long-term use that has been a problem with the prior art is achieved, combination of environraental resistance properties (heat resistance, hydrolysis resistance, weather resistance, chemical resistance, and the like) is well balanced, and thus markedly excellent long-term reliability is achieved. MEANS FOR SOLVING THE PROBLEMS [0016] A seal film for solar cell module of the present invention has the following construction (1). (1) The seal film for solar cell module includes: a resin film layer including a biaxially oriented film layer formed of a resin composition containing poly-p-phenylene sulfide as a major component; and a gas barrier layer formed of at least one selected from the group consisting of a metal, a metal oxide, an inorganic compound, and an organic compound. In the seal film for solar cell module, longitudinal and width direction heat shrink ratios at 150°C of the seal film for solar cell module are both within a range of -2 . 0% to +2.0%, and an absolute value of a difference between the longitudinal and width direction heat shrink ratios at 150°C is 2.0% or less. [0017] More specifically, the seal film for solar cell module of the present invention preferably has any of the following constructions (2) to (4). (2 ) In the seal film for solar cell module according to foregoing (1), a ratio (laminating ratio: B/AxlOO) of an overall thickness (B) of the biaxially oriented film layer to the thickness (A) of the seal film for solar cell module is 10% or more, the biaxially oriented film layer forming the seal film and being formed of the resin composition containing poly-p-phenylene sulfide as the major component. (3) In the seal film for solar cell module according to the foregoing item (1) or (2) , a high temperature volatile content of the biaxially oriented film formed of the resin composition containing poly-p-phenylene sulfide as the major component is 0.02% by mass or less. (4) A seal film for solar cell module in which a weather resistant resin layer is stacked on at least one surface of the seal film for solar cell module according to any one of the foregoing items (1) to (3) . [0018] A solar cell module of the present invention also has the following construction (5). (5) A solar cell module including the seal film for solar cell module according to any one of the foregoing items (1) to (4) disposed on at least one surface of the solar cell module. EFFECT OF THE INVENTION [19] According to the present invention, the seal film for solar cell module in which environmental resistance including heat resistance, hydrolysis resistance, weather resistance and chemical resistance (toxic-gas resistance) is improved and change with time in gas barrier property is effectively prevented. This is enabled by using a PPS film excelling in heat resistance, hydrolysis resistance and chemical resistance as the seal film, by controlling a heat dimensional change ratio of the seal film within a particular range, and by balancing heat dimensional change ratio characteristics in the longitudinal and width directions. In the seal film for solar cell module of the present inventicri, deterioration due to external environment including a harsh high temperature, a high humidity, a generated toxic gas, ultra-violet light and the like is prevented, and prevention of the gas barrier property deterioration due to long-term use that has been a problem with the prior art is achieved. The seal film for solar cell module has well-balanced combination of environmental resistance properties including heat resistance, hydrolysis resistance, weather resistance and chemical resistance {resistance to deterioration by a toxic gas), and consequently achieves an excellent long-term reliability. [0021] In addition, in the solar cell module using the seal film for solar cell module of the present invention, reduction in output due to penetration of water vapor can be significantly improved. The solar cell module is resistant to deterioration by hydrolysis, ultraviolet light and generated toxic gas, and thus excellent in environmental resistance. Furthermore, the solar cell module is excellent in lightweight properties and mechanical strength. BRIEF DESCRIPTION OF DRAWINGS [0022] [Fig. 1] Fig. 1 is a diagram showing a basic construction of the seal film for solar cell module of the present invention. [Fig. 2] Fig. 2 is a diagram showing an example of the construction of the solar cell module of the present invention. [Fig. 3] Fig. 3 is a diagram showing an example of the construction of the seal film for solar cell module of the present invention provided with a weather resistance resin layer. [Fig. 4] Fig. 4 is a diagrain showing a stack construction of the seal film for solar cell module of the present invention manufactured according to an embodiment. EXPLANATION OF REFERENCE NUMERALS [23] 1 Front sheet layer 2 Filling adhesive resin 3 Solar cell element 4 Back sheet layer 41 Gas barrier layer 41a Silicon oxide film layer used as a gas barrier layer 42 Resin film layer 42a Polyphenylene sulfide film layer 42b Film layer other than polyphenylene sulfide film layer 43 Gas barrier layer supporting film 44 Weather resistant layer BEST MODE FOR CARRYING OUT THE INVENTION [24] A basic construction of a seal film for solar cell module of the present invention is formed of two layers of a resin film layer 42 and a gas barrier layer 41 as shown in Fig. 1. In the present invention, a seal film for solar cell module refers to a seal film used as either or both of the front sheet and the back sheet provided on either sides of the solar cell module described below. [25] The seal film for solar cell module has a specific construction formed of a resin film layer 42 including: a biaxially oriented film layer formed of a resin composition containing poly-p-phenylene sulfide as a major component; and a gas barrier layer 41 fcrmed of at least one selected from the group consisting of a metal, a metal oxide, an inorganic compound, and an organic compound. In the resin film layer 42, longitudinal and width direction heat shrink ratios at 150°C of the seal film for solar cell module are both within a range of -2.0% to +2.0%, and an absolute value of a difference between the longitudinal and width direction heat shrink ratios at 150°C is 2.0% or less. [0026] The resin film layer 42 is formed of a plastic film, and has main roles to provide electrical insulation, to mechanically protect enclosed solar cell elements, and to take in light. In the present invention, it is important that the resin film layer includes a biaxially oriented film layer formed of a resin composition containing PPS as a major component (hereinafter sometimes abbreviated to a PPS film) in order to provide resistance to harsh external environment. [28] The resin film layer 42 may further include a plastic film layer other than the PPS film. Examples of the plastic film other than the PPS film include a polyester-based film, which may be stretched or unstretched, such as polyethylene terephthalate (hereinafter sometimes abbreviated to PET) or polyethylene naphthalate (hereinafter sometimes abbreviated to PEN) , an fluorine film, which may be stretched or unstretched, such as polytetrafluoroethylene (PTFE), a perfluoroalkoxy (PFA) resin formed of a copolymer of tetrafluoroethylene and perfluoro (alkyl vinyl ether), a copolymer of tetrafl-acrcethylene ar.d hexaflucropropylene, a copolymer of tetrafluoroethylene, perfluoro (alkyl vinyl ether) and hexafluoropropylene (EPF), a copolymer of tetrafluoroethylene and ethylene or propylene (ETFE), polychlorotrifluoroethylene resin (PCTFE) , a copolymer of ethylene and chlorotrifluoroethylene resin (ECTFE), vinylidene fluoride resin (PVDF), a vinyl fluoride resin (PVF), a olefin-based fluorine film, a nylon-based fluorine film, or the like. A single film of a PET film or a PEN film, and a laminated film using a PET film or a PEN film as some layers of the film are particularly preferable in consideration of a balance between processability, mechanical strength, weather resistance, price, and the like. [0029] Fig. 1 shows a basic construction of the seal film of the present invention. As for the thickness in the basic construction of the seal film of the present invention, when the overall thickness of the seal film for solar cell module is designated as (A) and the thickness of the PPS layer is designated as (B) , the laminating ratio (laminating ratio: (B/A xlOO)) of the PPS film is preferably 10% or more, more preferably 15% or more. The thickness of the PPS film layer is made 10% or more relative to the overall thickness of the seal film because a better effect of controlling the deterioration of the seal film due to a harsh external environment including a high temperature, a high hiomidity, a generated gas, ultra-violet light and the like can be obtained. It is an object of the present invention to obtain the above effect. The higher ratio of the thickness of the PPS film layer enhances more the effect of the present invention. The upper limit of the ratio of the thickness of the ?PS film layer is therefore up to near 100%. However, the higher ratio of the thickness of the PPS film layer sometimes causes the seal film to be brittle and to thereby tend to be split off. Therefore, in this respect, the upper limit is preferably 95%, more preferably 90%. [30] The PPS film layer may be formed of several separate laminated PPS film layers. Alternatively, the PPS film layer may of course be made of a single PPS film. In some cases, the PPS film is used as a base film of a gas barrier layer described below. Such a film is also included in the PPS film layer of the present invention. The thickness (A) of the seal film for solar cell module is the total of the thickness of the resin film layer and the thickness of the gas barrier layer. When the PPS film layer is formed of two or more laminated layers, the thickness of the PPS film layer (B) is the total of the thicknesses of these layers. [31] The gas barrier layer in the seal film of the present invention refers to a layer having barrier properties against water vapor and oxygen. To be specific, the gas barrier layer is foirmed of at least one selected from the group consisting of an inorganic compound, such as metal, metal oxide, silica or the like, and an organic compound, and can be formed by a conventionally known method including vapor deposition, sputtering, coating or the like. [32] For the gas barrier layer of the present invention, water vapor barrier properties are more important. The gas barrier layer of the present invention is a layer preferably achieving an initial value (value before an aging test) of water vapor permeability measured by a m.ethod based on JIS K7129-1992 B method (the same as a measurement method of the water vapor permeability of the seal film to be described later) of 2.0 g/m^/24hr or less. A preferred construction composition of the gas barrier layer includes aluminum oxide and silicon oxide. [33] The gas barrier layer may be directly provided on the foregoing resin film layer by the abovementioned vapor deposition method and the like; alternatively, the gas barrier layer once provided on another film may be provided on the resin film with an adhesive. The latter method is generally used because of the low price. The foregoing another film is not particularly limited; however, in general, a PET, PEN, PPS, or fluorine-based film or the like is preferably used as the film. The thickness of these films is not particularly limited and preferably within a thickness range of 5 to 25 ijm from the viewpoints of the processability and economy of the vapor deposition, sputtering, coating and the like. [34] In the present invention, poly-p-phenylene sulfide refers to a polymer preferably containing 90 mol% or more, more preferably 95 mol% or more of the PPS component and being formed of construction units represented by the following formula (1) . The content of the PPS component less than 90 mol% causes crystallinity, thermal transition temperature and melting point of the polymer to be low. Consequently, advantages of a resin composition containing PPS as a major component such as heat resistance, hydrolysis resistance, mechanical properties and chemical resistance cannot sometimes CD [35] A unit containing other copolymerizable sulfide bond may¬be contained in the above PPS resin, as long as the amount of unit is less than 10 mol%, preferably less than 5 mol% relative to the repeated units. In this case, the construction units may be copolymerized by either a random type or a block type copolymerization method. [36] successfully be exhibited. [Chemical formula 1] In the present invention, the resin composition containing PPS as a major component refers to a composition containing 60% by mass or more of PPS. If the content of PPS is less than 60% by mass, it is difficult to successfully exhibit the mechanical properties, heat resistance, hydrolysis resistance, moisture absorption dimension stability, chemical resistance and the like of a layer formed of the composition of the seal film for solar cell module of the present invention. As the remaining contents less than 40% by mass, the composition may contain additives such as a polymer other than PPS, an inorganic or organic filler, a lubricant, and a coloring agent. In addition, a melt viscosity of the PPS composition is preferably within a range of 100 to 50000 poise at 30°C and at a shear velocity of 200 sec'^ because of the easiness of molding and film formation processing, and more preferably 500 to 20000 poise. A biaxially oriented film formed of the PPS resin composition refers to a film formed by melt-extruding, biaxially extending and heat-treating a resin composition containing the aforementioned PPS as a major component and preferably has a thickness within a range of 5 to 3 00 ym from the viewpoint of processability, mechanical properties and environmental resistance properties. A PPS film containing additives within the above range and colored in white or black may be used. [38] A PPS film having a high temperature volatile content of 0.02% by mass or less is particularly preferable from the viewpoint of particularly important ultra-violet resistance among various kinds of weather resistance. The high temperature volatile content here refers to a difference between the volatile content (% by mass) generated from the PPS film at 250°C and the volatile content (% by mass) generated from the PPS film at 150°C and is a value determined by using the equation shown below. The PPS film having more than 0.02% by mass of the high temperature volatile content is not preferable because the film contains a large amount of impurities and tends to be changed in color to brown when irradiated by ultra-violet light and, generally, deterioration in the mechanical properties are fast. •High temperature volatile content (% by mass) = {volatile content generated at 250°C (% by mass)} - {volatile content generated at 150°C (% by mass)} In the present invention, a solar cell module refers to a system converting sunlight into electricity. An example of general model of the structure of the solar cell module is shown in Fig. 2. That is, the basic construction is formed of a front sheet layer 1, a filling adhesive resin layer 2, solar cell elements 3, a filling adhesive resin layer 2 and a back sheet layer 4 in this order from a sunlight incoming side. In some cases, the solar cell module is incorporated into a residential roof, mounted to a building or a fence or used in an electronic component. Such a solar cell module includes one which is called a day lighting type or a see-through type, allows sunlight to penetrate and is thus used in a window or sound barrier wall of a freeway and a railway. A flexible type is also practically used. The front sheet layer refers to a layer provided to allow sunlight to efficiently penetrate and to protect the internal solar cell elements. [41] The filling adhesive resin layer is used for the purposes of adhesion and filling for accommodation and seal of the solar cell elements between the front sheet and the back sheet, and needs to have weather resistance, water resistance (hydrolysis resistance), transparency, adhesion properties, and the like. Examples suitably used for the filling adhesive resin layer include an ethylene-vinyl acetate copolymer resin (hereinafter sometimes abbreviated to EVA), polyvinyl butyral, ethylene-vinyl acetate partial oxide, a silicone resin, an ester-based resin, an olefin-based resin, and the like. EVA is most general. The back sheet layer is used to protect the solar cell elements on the back surface side of the solar cell module and needs to have water vapor blocking performance, electrical insulation performance, mechanical properties, and the like. The back sheet includes a white type one reflecting sunlight incoming from the front sheet side for reuse of the sunlight, a type colored in black or the like in consideration of design, or a transparent type one allowing sunlight to also enter the module from the back sheet side. The present invention can be applied to all these types. [43] In the present invention, the seal film for solar cell module refers to a seal film used as both or one of the front sheet and the back sheet as described above and has a basic construction formed of two layers of a resin film layer and a gas barrier layer as described above. The thickness of each of the front sheet and the back sheet is preferably within a range of 30 iJin to 7 00 pin from the viewpoints of mechanical strength, electrical insulation properties and processability, and more preferably within a range of 35 ym to 500 ijm. In the present invention, the thickness of the seal film for solar cell module is preferably within a range of 100 ym to 700 iJm, more preferably 120 lom to 500 lom for the front sheet, and is preferably within a range of 3 0 pm to 400 pm, more preferably 35 laiti to 3 00 Vim for the back sheet. [44] In the present invention, it is important that the longitudinal direction and width direction heat shrink ratios at 150°C of the aforementioned seal film for solar cell module are both within a range of -2.0% to +2.0%, preferably -1.7% to +1.7%, mors preferably -1.5% tc -1.5%. Furthermore, it is important that the absolute value of the difference between the longitudinal and width direction heat shrink ratios at 150°C is controlled so as to be 2 .0% or less, preferably 1.5% or less. [45] That is, heat shrinkage is prevented as much as possible and the characteristics in the longitudinal and width directions are balanced as well as possible. The deterioration of the gas barrier properties of the seal film for solar cell module after a long time use can thereby be controlled to improve the reduction with time in the output of the solar cell module. This is the largest effect of the present invention. [46] Here, in the present invention, the heat shrink ratio refers to a value after treatment at 150°C for 30 minute measured based on a dimensional change measuring method of JIS C2151-1990 and represented by a minus sign for expansion and by a plus sign for shrinkage. In the present invention, the heat shrink ratio is determined by the value after treatment at 150°C for 30 minute because of the following reason. That is, the maximum temperature in the use environment of a solar cell module is usually about 100°C to 120°C. The processing temperature of the seal film and the temperature for processing such as the construction of the solar cell module are about 120°C to 180°C. Accordingly, the heat treatment condition of 150°C and 30 minute near the above use environment temperature and the above processing temperature is selected from the temperature conditions of the above JIS standards. If the seal film has a heat shrink ratio within a range specified according to the present invention under the heat treatment condition, the gas barrier properties do not deteriorate in actual use environment and processing. As a result, an excellent seal film for solar cell module can be formed. [47] If any one of the longitudinal direction and width direction heat shrink ratios is out of a range of -2. 0% to +2.0%, the gas barrier properties significantly deteriorate with time. The output of the solar cell module consequently is to be out of the acceptable range of the output reduction with time. The above acceptable range is an object of the present invention. As a result, an object of the present invention cannot be achieved. [48] The cause for this is estimated to be as follows. That is, between a resin layer and a gas barrier layer formed of a vapor deposited overcoat layer of a metal oxide or the like which constructs the foregoing seal film for solar cell module of the present invention and between these layers and the filling adhesive resin layer to fix the solar cell elements by filling, the resin film layer repeats change in dimension due to shrinkage and expansion under a mount environment. Accordingly, stress is applied to the overcoat layer made of a hard metal oxide forming the gas barrier layer to thereby create cracks, resulting in the deterioration of water vapor barrier properties. [49] Furthermore, if the absolute value of a difference between longitudinal and width direction heat shrink ratios exceeds 2.0%, the same problem occurs. Consequently, an object of the present invention cannot be achieved. Therefore, the two requireir.ents are most importanr in the present invention. The exceedance of the absolute value of a difference between heat shrink ratios beyond 2.0% refers to a case in which, for example, the seal film expands or shrinks excessively more in one of the longitudinal and width directions than in the other, or a case in which the seal film expands in one direction and shrinks in the other direction, and thus the difference between heat shrink ratios exceeds 2.0%. The reason why the same problem arises when the absolute value of a difference between the longitudinal and width direction heat shrink ratios exceeds 2.0% in the above manner is estimated to be as follows. A metal oxide constructing the gas barrier layer receives larger stress when the seal film unequally expands or shrinks in the longitudinal and width directions as compared to when the seal film equally expands or shrinks in the longitudinal and width directions. Note that, in the present invention, a difference between longitudinal and width direction heat shrink ratios refers to a value obtained by determining each of the longitudinal and width direction heat shrink ratios to two decimal places and by then rounding off the absolute value of the difference between the determined values to one decimal place. [0050] Furthermore, the seal film for solar cell module of the present invention preferably has at least one surface laminated with a resin layer 44 having weather resistance (hereinafter referred to as weather resistant resin layer) as shown in Fig. 3 to provide good weather resistance. In particular, it is more preferable that the resin layer 44 having weather resistance be used on the front sheet side. Note that weather resistance refers to properties uhat deterioration by ultra-violet light irradiation hardly occurs. As the weather resistant resin layer, for example, a fluorine resin sheet, a polycarbonate resin and an acryl resin are particularly preferable from the viewpoints of weather resistance and transparency. The thickness of the weather resistant resin layer is preferably within a range of 5 ym to 100 lam from the viewpoints of transparency, processability, economy, and weight reduction. Here, as the fluorine resin sheet, the aforementioned sheet can be used. Resin sheets of a derivative or a modified resin of polycarbonate or acryl resin are included. As for the acryl resin, a benzotriazole-based monomer-copolymerized acryl resin is particularly preferable from the viewpoints of weather resistance, transparency and thin film formation. The benzotriazole-based monomer-copolymerized acryl resin refers to a resin obtained by copolymerizing a benzotriazole-based reactive monomer and an acryl monomer, and may be in any form such as an organic solvent-soluble one, water-dispersed one and the like. The banzotriazole-based monomer may be a monomer having benzotriazole in basic skeleton and an unsaturated double bond, and not particularly limited. A preferred monomer is 2-{2,-hydroxy-5,-methacryloxyethylphenyl)-2H-benzotriazole. Acryl monomers usable for copolymerization with this monomer include alkyl acrylate, alkyl methacrylate (where the alkyl group is a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a t-butyl group, a 2-ethylhexyl group, a lauryl group, a stearyl group, a cyclohexyl group or the like), a monomer having a crosslinkable functional group such as a monomer having a carboxyl group, a msthylol group, an acid anJiydride group, a sulfonate group, an amide group, a methylolized amide group, a methylolized amino group (including a substituted amino group) , an alkylolized amino group, a hydroxyl group, an epoxy group or the like. Examples of the monomer having the above described functional group include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, vinylsulfonic acid, styrenesulfonic acid, acrylamide, methacrylamide, N-methylmethacrylamide, methylolized acrylamide, methylolized methacrylamide, diethylaminoethylvinylether, 2-aminoethylvinylether, 3-aminopropylvinylether, 2-aminobutylvinylether, dimethylaminoethyl methacrylate and monomers obtained by methylolizing the above amino groups, (3-hydroxyethyl acrylate, p-hydroxyethyl methacrylate, (3-hydroxypropyl acrylate, p-hydroxypropyl methacrylate, 3-hydroxyvinyl ether, 5-hydroxypenthyl vinyl ether, 6-hydroxyhexyl vinyl ether, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, glycidyl acrylate, glycidyl methacrylate and the like; however, the monomer having the above described functional group is not necessarily limited thereto. In addition to the above monomers, monomers such as acrylonitrile, methacrylonitrile, styrene, butyl vinyl ether, a monomer or dialkyl ester of maleic acid or itaconic acid, methyl vinyl ketone, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl pyridine, vinyl pyrrolidone, alkoxysilane having a vinyl group, polyester having an unsaturated bond and the like may be used as a copolymerization component. [0051] In the present invention, one or more kinds of the above acr-yl-base monomers may be copolwierized. in any ratio. Methacrylate or styrene is preferably contained at a ratio of 50% by mass or more, more preferably 7 0% by mass or more, in an acryl component from the viewpoint of the hardness of the laminated film. A benzotriazole-based monomer and an acryl monomer are preferably copolymerized at a copolymerization ratio of the benzotriazole-based monomer of 10 to 70% by mass or less, more preferably 20 to 65% by mass or less, particularly preferably 25 to 60% by mass or less from the viewpoints of weather resistance, the adhesion properties of the weather resistant resin layer to the seal film for solar cell module and the durability of the weather resistant resin layer. The molecular weight of the copolymerization monomer is not particularly limited, and preferably 5000 or more, more preferably 10000 or more from the viewpoint of the durability of the weather resistant resin layer. A laminating thickness is not particularly limited, and preferably within a range of 0.3 to 10 pn^ from the viewpoints of weather resistance and blocking prevention. [52] A circuit may be formed of a metal layer, a conductive resin layer, a transparent conductive layer or the like on the surface of the seal film for solar cell module of the present invention. [53] Next, an example of a method of manufacturing the seal film for solar cell module of the present invention will be described. Firstly, a method of producing a PPS film constructing che seal film for solar cell inodule of rhe present invention wi 11 be described. [55] The PPS is produced by a method in which alkaline sulfide and p-dichlorobenzene are reacted with each other in a polar solvent at a high temperature and a high pressure. In particular, sodium sulfide and p-dichlorobenzene are preferably reacted with each other in an amide-based polar solvent having a high boiling point such as N-methyl-pyrrolidone. In this case, it is particularly preferable that a so-called polymerization aid such as caustic alkali or a carboxylic acid salt of an alkali metal be added to control a polymerization degree and that reaction be carried out at 230 to 280°C. The pressure in a polymerization system and a polymerization time are suitably determined depending on the kind and amount of an aid to be used and a desired polymerization degree. The obtained polymer is further preferably washed by using water or an organic solvent containing no metal ion to remove a byproduct salt formed during polymerization and the polymerization aid. [56] Inert inorganic particles or the like are mixed with the PPS polymer thus obtained to produce a PPS resin composition. The mixing method is as follows. Both are mixed and blended by a mixer and the like. Thereafter, the mixture is pushed out in a gut shape while melt-extrusion-mixed by a known method typified by an extruder, and then cut into pellets. A mixture formed by melt-mixing an additive in a high concentration is once cut into pellets. Then, the pellets may be mixed with other pellets not containing the additive to dilute the concentration of chs addicive. [57] It is preferable that the PPS film constructing the resin film layer of the present invention contain a lower amount of impurities from the viewpoint of weather resistance (ultra-violet resistance) . That is, the PPS film particularly preferably contains 0. 02% or less by mass of a high temperature volatile content because the change in color by ultra-violet light and the deterioration of the mechanical properties to hardly occur. A method of reducing the high temperature volatile content is to dry a polyphenylene sulfide resin composition obtained in the above manner preferably under a reduced pressure, more preferably under a reduced pressure of a vacuum degree of 0 to 50 mmHg, preferably at 120 to 200°C, more preferably 160°C to 195°C, and preferably for 3 hours or more, more preferably for 5 to 10 hours while being stirred by a mixer. [58] The above composition is further dried again under a reduced pressure, preferably at a vacuum degree of 0 to 50 mmHg, at 120°C to 170°C and for 1 hour or more. The amount of volatile content to be noted can be controlled within a targeted range by carrying out drying in two steps in the above manner. At this time, a difference obtained by subtracting the volatile content at 150°C from the volatile content at 250°C of the resin composition obtained by the above processes is made to be 0.3% by mass or less. The high temperature volatile content of the PPS film produced by melt-extruding, casting, biaxially stretching and heat-treating the resin composition as described below can be controlled to be 0.02% by mass or less. Drying may be carried out in multi steps, that is, the resin composition is dried, then gradually cooled to a room temperature and dried again. Here, a drying temperature exceeding 200°C may lead to thermal deterioration of the polymer to generate a foreign matter, or cause problems in film formation such as solidification of the dried raw material and thickness variation and the like. Furthermore, when the temperature is less than 120°C, an effect of reducing a difference in the volatile content referred to in the present invention cannot be achieved. In addition, the polymerized powder raw material may directly be dried in multi steps by the above method. The high temperature volatile content to be noted can be controlled within a desired range by the following method as well as the above method. [0060] The resin composition is obtained by the same method as described above. The resin composition is again supplied to an extruder having a vent hole. The resin composition is preferably dried under a reduced pressure, preferably under a reduced pressure of a vacuum degree of 0 to 50 mmHg, preferably at 120 to 200°C, more preferably at 160°C to 195°C, preferably for 3 hours or more, more preferably for 5 to 8 hours while being stirred by a mixer, and then again extruded. At this time, drying is more preferably carried out in two steps by the same method as described above. The high temperature volatile content can be reduced within a targeted range by carrying out extrusion in multiple steps in the above manner. [0061] The PPS obtained above is then formed into a biaxially stretched film to obtain a biaxially oriented layer of the PPS. The PPS resin composition obtained above is supplied to a melt-extruder typified by an extruder. The molten polymer is then continuously extruded from a slit-shaped die such as a T die and thereafter forcibly cooled to obtain an unoriented and uncrystallized sheet. As for such a forced cooling means, a method in which the molten polymer is cast on a cooled metal drum to be cooled to a glass transition temperature (hereinafter sometimes abbreviated to Tg) or less of the PPS for solidification is most preferable because the thickness irregularity is small. [0062] The sheet obtained in such a manner is biaxially stretched. A sequential biaxial stretching method and a simultaneous biaxial stretching method including a tenter method and a tubular method can be used as the stretching method. Conditions under which the sheet is biaxially stretched are somewhat different depending on the properties of the polymer to be used and the stretching method. In the sequential biaxial stretching method, it is preferable that stretching temperatures of both the longitudinal direction (hereinafter sometimes abbreviated to MD) and the width direction (hereinafter sometimes abbreviated to TD) of the film be in a range of 85 to 105°C, stretching magnifications in both the longitudinal direction and the width direction be 1.5 to 4.5 and a MD/TD stretching magnification ratio (stretching magnification in MD/stretching magnification in TD) be in a range of 0.6 to 1.3, from the viewpoints of the thickness irregularity of the film, control of molecular orientation and the balance of heat shrink ratios. Furthermore, it is particularly preferable that orientation factors OF be controlled to be 0.33 to 0.75 in both an edge direction and an end direction and the OF ratio between both directions (edge direction/end direction) be in a range of preferably 0.7 to 1.4, more preferably 0.8 to 1.3 from the viewpoints of the mechanical properties deterioration by the environment and the balance of heat shrink ratios in both axes referred to in the present invention. Here, the orientation factor OF measured in the edge direction (or end direction) refers to a value defined by a ratio I