DESCRIPTION A THERMOPLASTIC RESIN COMPOSITION, A SOLAR CELL SEALING SHEET, AND A SOLAR CELL TECHNICAL FIELD [0001] The present invention relates to the sheet for sealing a solar cell between a front and a back material made of a sheet or a plate of a glass, a plastic and the like, particularly relates to a non-crosslinked solar cell sealing sheet capable of performing thermal lamination at low temperature. BACKGROUND ART [0002] Conventionally, as a solar cell sealing sheet of this type, an organic peroxide-containing ethylene-vinyl acetate copolymer (abbreviated as EVA) has been generally used, since it has resin characteristics of good flexibility, high transparency, and excellent long-term durability by blending with an appropriate additive such as a weathering stabilizer, an adhesion promoter and the like. [0003] However, because EVA has such drawbacks as lower melting point and poorer heat resistance that causes heat distortion at the temperature where a solar cell module is used, the hest-resistance has been effected by blending it with an organic peroxide in order to form a crosslinked structure. [0004] A solar cell sealing sheet can be formed by a publicly-known sheet forming method capable of forming a polyolefin, but such a method as blending the organic peroxide has problems to cause deterioration of high speed productivity since the sheet formation is forced to be performed at low temperature in order to prevent decomposition of the organic peroxide. [0005] In the process for producing a solar cell having the structure of (a surface protection layer = glass, plastics)/(a solar cell sealing sheet)/(a power module = a solar cell element) / (a solar cell sealing sheet) / (a surface protection layer = glass, plastics) , generally employed are two processes composed of a tentative adhesion process by thermal lamination under vacuum and a crosslinking process in an oven at high temperature. This crosslinking process by organic peroxide requires several ten minutes, and therefore shortening of the crosslinking process time or elimination itself is strongly requested. [0006] Further, there exists the concern that the power generation efficiency may be lowered by the adverse effect on a power module caused by a decomposition gas (acetic acid gas) from EVA or by the vinyl acetate group of EVA itself. In order to avoid the above-mentioned problems associated with EVA, a solar cell sealing sheet employing an ethylene-a-olefin copolymer (Japanese Patent Laid-Open Publication No. 2000-91611) was proposed. It has been considered that these materials may reduce the adverse effects on a power module, but the balance between heat resistance and flexibility was not sufficiently good, and in addition, good heat resistance could not be realized without crosslinking, so that it has been difficult to eliminate the crosslinking process (Patent Document 1) -[0008] Inventors of the present invention have tackled the development of a solar cell sealing sheet usable even without being crosslinked, based on polypropylene or a copolymer mainly composed of propylene having excellent heat resistance. As a result of investigation by the present inventors, it has become clear that, although the solar cell sealing sheet based on such polypropylene or a copolymer mainly composed of propylene has good flexibility and heat resistance, there exist problems that the applicable temperature range for thermal lamination (process to adhere or fuse by heating a stack of a solar cell power module, a solar cell sealing sheet of the present invention, and further a glass or a back sheet) during solar cell manufacturing is very narrow. During thermal lamination, low temperature as possible (specifically 160°C or less, or more preferably below 160°C) is preferred for thermal lamination, since a power module constituting the above-mentioned solar cell and a surface protection layer are damaged at high temperature. [0010] In Patent Document 2, thermal lamination of a transparent resin between 120°C and 160°C is also described. Patent Document 1: Japanese Patent Laid-Open Publication No. 2000-91611 Patent Document 2: Japanese Patent Laid-Open Publication No. Hll-163377 DISCLOSURE OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION [0011] By investigation of the present inventors, it has become clear that, when a material based on polypropylene or a copolymer mainly composed of propylene is heated at the neighborhood temperature of the melting point, cloudiness is generated, and thus transparency of a solar cell sealing sheet using this material is seriously damaged. Therefore, the present inventors considered that to develop a non-crosslinked solar cell sealing sheet satisfying both heat resistance and thermal lamination roperties at low temperature by solving these problems was the subject. [0012] An object of the present invention is to provide a thermoplastic resin composition and a solar cell sealing sheet comprised thereof having sufficient heat resistance for practical use with a property that cloudiness is not generated by thermal lamination at low temperature, while retaining flowability in the extent of allowing for molding. MEANS TO SOLVE THE PROBLEMS [0013] A first thermoplastic resin composition of the present invention comprises 1 to 95 % by weight of a propylene-based polymer (A) and 5 to 99 % by weight of a propylene-based copolymer (B) with at least one a-olefin having 2 to 20 carbon atoms other than propylene, wherein (A) has the following characteristics of (i) and (ii) , and (B) has a melting point below 80°C or does not show a melting point as measured by a differential scanning calorimeter (here, the sum of (A) and (B) is 100 % by weight). Characteristics of a propylene-based polymer (A): (i) Melting point measured by a differential scanning calorimeter (DSC) method is in the range of 80 to 135°C. (ii) Endotherm attributable to crystal melting is not observed at 140°C or more in the endothermic curve measured by a differential scanning calorimeter (DSC) method. [0014] In the first thermoplastic resin composition of the present invention, it is preferable for a propylene-based polymer (A) to further satisfy the following (iii). (iii) Melting point (Tm) measured by a differential scanning calorimeter (DSC) and Vicat softening temperature (Tv) measured in accordance with ASTM D1525 satisfy Equation (I) : 0.234 x (Tm)1,277 < Tv < Tm Equation (I) (here, Tm is in the range of 80 to 135°C). [0015] The first thermoplastic resin composition of the present invention may contain 0.1 to 5 parts by weight of a coupling agent (Y) relative to total 100 parts by weight of the propylene-based polymer (A) and the propylene-based copolymer (B). [0016] It is preferable that the first thermoplastic resin composition mentioned above has 0.05 g/lOmin or more of MFR at 230°C. [0017] A thermoplastic resin composition obtained by melt-kneading a mixture, comprising 1 to 95 % by weight of the propylene-based polymer (A) and 99 to 5 % by weight of the propylene-based copolymer (B) (the sum of (A) and (B) is 100 % by weight) , and 0.1 to 5 parts by weight of the coupling agent (Y) relative to 100 parts by weight of the sum of (A) and (B) in the presence of an organic peroxide is one preferred embodiment of the present invention (hereinafter it may be called as "the second thermoplastic resin composition") . It is preferable that the second thermoplastic resin composition has 0.05 g/lOmin or more of MFR at 230°C. [0018] Both of these first and second thermoplastic resin compositions are suitably used for solar cell sealing. A solar cell sealing sheet of the present invention comprises the first or the second thermoplastic resin composition. [0019] A solar cell of the present invention comprises using the above-mentioned solar cell sealing sheet. [0020] A third thermoplastic resin composition of the present invention comprises 1 to 95 % by weight of a propylene-based polymer (AA) and 5 to 99 % by weight of a propylene-based copolymer (BB) with at least one a-olefin having 2 to 20 carbon atoms other than propylene, wherein (AA) satisfies the following (ia) and (iia) and (BB) has a melting point below 80°C or does not show a melting point as measured by a differential scanning calorimeter (DSC) method. A melting point measured by a differential scanning calorimeter (DSC) method is 80°C or more and 140°C or less, (iia) Molecular weight distribution obtained by a gel permeation chromatography (GPC) is 3 or less. [0021] In the third thermoplastic resin composition of the present invention, the propylene-based copolymer (BB) is preferably a propylene-ethylene-a-olefin copolymer (BB-1); A propylene-ethylene-a-olefin copolymer (BB-1) comprises 45 to 92 mol% of the constituent unit derived from propylene, 5 to 25 mol% of the constituent unit derived from ethylene, and 3 to 30 mol% of the constituent unit derived from an a-olefin having 4 to 20 carbon atoms, and has its melting point below 80°C or does not show a melting point as measured by a differential scanning calorimeter. [0022] In the third thermoplastic resin composition of the present invention, 0.1 to 5 parts by weight of a coupling agent (Y) may be blended relative to 100 parts of the sum of the propylene-based polymer (AA) and the propylene-based copolymer (BB). [0023] It is preferable that the third thermoplastic resin composition of the present invention has 0.05 g/lOmin or more of MFR at 230°C. The third thermoplastic resin composition is suitably used for solar cell sealing. [0025] Another solar cell sealing sheet of the present invention comprises the third thermoplastic resin composition. Another solar cell of the present invention comprises using the above-mentioned solar cell sealing sheet formed from the third thermoplastic resin composition of the present invention. EFFECT OF THE INVENTION [0026] By using the first or the second thermoplastic resin composition of the present invention, a solar cell sealing sheet having sufficiently good heat resistance for practical use with a property that cloudiness is not generated by thermal lamination at low temperature, while retaining flowability in the extent of allowing for molding, can be provided. By using this solar cell sealing sheet, the applicable temperature range for thermal lamination during the solar cell manufacturing is widened, and specifically, damage to other members (a power module or a surface protection layer) can be reduced since thermal lamination can be performed at lower temperature. Furthermore, since the crosslinking process causing deterioration of resin flowability is not necessary for effecting the heat resistance, the time for solar cell manufacturing process can be shortened significantly and also the recycling of the solar cell after use can be easier. In addition, the first thermoplastic resin composition blended with the coupling agent (Y) becomes a thermoplastic resin composition having excellent adhesive properties with an objective material as well. The second thermoplastic resin composition also becomes a thermoplastic resin composition having excellent adhesive properties with an objective material. [0027] By using the third thermoplastic resin composition of the present invention, a solar cell sealing sheet having sufficiently good heat resistance for practical use with a property that cloudiness is not generated by thermal lamination at low temperature, while retaining flowability in the extent of allowing for molding, can be provided. By using this solar cell sealing sheet, the applicable temperature range for thermal lamination during the solar cell manufacturing is widened, and specifically, damages to other members (a power module or a surface protection layer) can be reduced since thermal lamination can be performed at lower temperature. Furthermore, since the crosslinking process causing deterioration of resin flowability is not necessary for effecting the heat resistance, the time for solar cell manufacturing process can be shortened significantly and also the recycling of the solar cell after use can be easier. BRIEF DESCRIPTION OF THE DRAWINGS [0028] Figure 1 shows the DSC curve when the temperature is raised from -150°C to 200°C for the propylene-based polymer (A-1) used in Example at the heating rate of 20°C/min. Figure 2 shows the DSC curve for the propylene-based polymer (A-2) used in Example. Figure 3 shows the DSC curve for the propylene-based polymer (A-3) used in Example. Figure 4 shows the DSC curve for the propylene-based polymer (A-4) used in Example. Figure 5 shows one embodiment in which the solar cell sealing sheet of the present invention is applied. Figure 6 shows the samples used for heat resistance test in Example 11 and Comparative Example 11. Figure 7 shows the samples used for the glass-adhesion test in Example 11 and Comparative Example 11. BEST MODE FOR CARRYING OUT THE INVENTION [0029] The first and second thermoplastic resin compositions, a solar cell sealing sheet using the compositions thereof, and a solar cell using the solar cell sealing sheet thereof (A) A propylene-based polymer As a propylene-based polymer used in the present invention, there may be mentioned a propylene homopolymer or a copolymer of propylene with at least one a-olefin having 2 to 20 carbon atoms other than propylene. Here, examples of the a-olefin having 2 to 20 carbon atoms other than propylene include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-l-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like, though a copolymer with ethylene and/or an a-olefin having 4 to 10 carbon atoms may be preferably used. [0030] The constituent unit derived from a-olefins in the polypropylene may be 35 mol% or less, preferably 20 mol% or less (here, the sum of the constituent unit derived from propylene and the constituent unit derived from a-olefin (other than propylene) is 100 mol%) . Further two or more kinds of the constituent units derived from the a-olefins other than propylene may be contained. [0031] These a-olefins may form a random or a block copolymer with propylene, though a random copolymer may be preferably used in the present invention. [0032] As mentioned above, in the present invention a random copolymer of propylene with an a-olefin having 2 to 20 carbon atoms (other than propylene) is preferred, wherein the amount of the constituent unit derived from a-olefin having 2 to 20 carbon atoms is preferably 1 to 7.5 mol%, more preferably 2 to 7 mol%, and further preferably 2.5 to 6.5 mol%. [0033] Further, a propylene-based polymer (A) has desirably the melt flow rate (MFR) of 0.01 to 1000 g/lOmin, and preferably 0.05 to 100 g/lOmin as measured at 230°C under a load of 2.16 kg in accordance with ASTM D1238. [0034] The melting point (the peak of the endothermic curve showing melting of propylene-based polymer crystals) of the propylene-based polymer (A) of the present invention as measured by a differential scanning calorimeter (DSC) is in the range of 80 to 135°C, preferably 100 to 135°C, more preferably 110 to 130°C, and particularly preferably 115°C to 130°C. [0035] In the propylene-based polymer (A) of the present invention, the endotherm due to crystal melting is not observed at 140°C or more in the endothermic curve as measured by a differential scanning calorimeter (DSC) method. Here, the methods for measuring melting point and for confirmation of whether or not the endotherm at 140°C or more exists are as those described in " (1) Melting point and confirmation of presence or absence of the endotherm at 140°C or more" in Examples. [0036] Here, the phrase "the endotherm due to crystal melting is not observed" is defined as follows. [0037] Namely, dried alumina packed in the same aluminum pan as the one described in 1-1} of the above-mentioned " (1} Melting point and confirmation of presence or absence of the endotherm at 140°C or more" is prepared as the reference, and then the vertical axis value (heat quantity) of the endothermic curve obtained according to the conditions of (i) to (iii) in the above-mentioned 1-1) is taken as follows. [0038] Dtop = the vertical axis value at the peak point of melting point (maximum melting point) Di4o°C = the vertical axis value at 140°C Di5o°C = the vertical axis value at 150°C Further, Dl and D2 are defined as below, and when they satisfy Equation (1) or preferably Equation (1'), it means that the endotherm due to crystal melting is not observed at 14 0°C or more. [0039] Dl = Dtop - D150°C D2 = Di40°C - Di5o°C D2/D1<0.05 Equation (1) D2/D1<0.03 Equation Here, D2 may take a negative value. Here, the DSC measurement conditions to confirm melting point and the quantity of heat of fusion are those described in Examples. [0041] A propylene-based polymer (A) has the tensile modulus of usually 600 MPa or more, preferably 700 MPa or more, and more preferably 750 MPa or more as measured at 23°C by using a dumbbell in accordance with JIS K7113-2, the chuck distance of 80 mm, and the tensile rate of 200 mm/min, though the modulus is not particularly restricted to these values. [0042] The sample for the measurement is the press sheet obtained by hot-pressing a sample at 190°C between the upper and the lower SUS molds with 4-mm thickness, followed by rapid cooling with a cooling chiller of 20°C for molding, then kept for 72 hours or longer. [0043] The propylene-based polymers (A) of the present invention are suitably those whose melting point (Tm) measured by a differential scanning calorimeter (DSC) and Vicat softening temperature (Tv) measured in accordance with ASTM D1525 satisfy the following Equation (2) or preferably Equation (2)'. 0.234 x (T)1-277 < Tv < Tm Equation (2) 0.234 x (T)1-277 < Tv < 0.902 x (Tm)1'011 Equation (2)': (here, Tm is between 80°C and 135°C). [0044] The propylene-based polymer (A) having (i) melting point of 135°C or less and satisfying the above-mentioned (ii) indicates that it has a narrow composition distribution, namely a narrow melting point distribution. [0045] The thermoplastic resin composition of the present invention using such propylene-based polymer (A) can maintain good transparency because less cloudiness takes place even though the temperature of the thermal lamination is further lowered. [0046] The propylene-based polymer (A) having (i) melting point of 135°C or less and satisfying the (ii) , and further the above-mentioned relationships between melting point Tm and Vicat softening temperature Tv, means that it is composed of molecules having homogeneous composition distribution. [0047] Generally, polypropylene has lower Vicat softening temperature (Tv) than melting point (Tm), and especially polypropylene with wider composition distribution tends to have larger difference between melting point Tm and Vicat softening temperature Tv. On the contrary, Tm and Tv satisfying the above equations (the difference between melting point Tm and Vicat softening temperature Tv is small) means that the propylene-based polymer (A) has a very narrow composition distribution. [0048] The sample for the measurement of the Vicat softening point is the press sheet that is obtained by hot-pressing a sample at 190°C between the upper and the lower SUS molds with 4-mm thickness, followed by rapid cooling with a cooling chiller of 20°C for molding, then kept for 72 hours or longer. [0049] The thermoplastic resin composition of the present invention using such propylene-based polymers (A) can maintain good transparency because cloudiness does not take place even though the thermal lamination is performed at the neighborhood temperature of the melting point (namely around at 150°C) . [0050] As a reason for this, it is speculated that such propylene-based polymer (A) does not contain a component with high-melting point (namely a component showing the endotherm at 135°C or more) because of a homogeneous composition distribution, and thus its crystalline lamella and crystalline domain size formed by crystallization become homogeneous. The propylene-based polymer (A) of the present invention may be used either in isotactic or syndiotactic structures. In addition, plural propylene-based polymers (A) may be used in combination as appropriate, and for instance, two or more kinds of components having different melting point, rigidity, or molecular weight may be also used. [0052] The above-mentioned propylene-based polymer (A) is obtained by polymerizing propylene or copolymerizing propylene with other a-olefin by using a Ziegler catalyst composed of solid catalyst component containing, for example, magnesium, titanium, halogen and an electron-donor as essential components, an organoaluminum compound, and an electron-donors, or by using a metallocene catalyst composed of a metallocene compound as one component, though the polymer obtained by using a metallocene catalyst system composed of a metallocene compound as one component can be preferably used as the propylene-based polymer (A) having the above-mentioned characteristics. [0053] As the metallocene catalyst to be used, a metallocene catalyst composed of a publicly-known metallocene compound capable of polymerizing an a-olefin, an organoaluminum oxy-compound and/or a compound capable of forming an ion pair by reacting with a metallocene compound may be mentioned, but a metallocene catalyst capable of performing a stereoregular polymerization affordable such structures as isotactic or syndiotactic structure and the like may be preferably mentioned. For instance, they can be produced by using the catalysts described in the pamphlet of International Publication WO 2001-27124 and in Japanese Patent Laid-Open Publication No. 2006-52313. Preferred specific examples of the a-olefin used for copolymerization with propylene include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-l-pentene, 1-octene and the like. [0054] A commercially available polymer may be also used as (A) . For example, a propylene-based polymer (A) that satisfies Equation (2), preferably Equation (2)', may be produced by fractionally removing a component with low melting point from a propylene-based polymer that does not satisfy Equation (2). [0055] (B) A propylene-based copolymer The propylene-based copolymers (B) of the present invention is a copolymer of propylene with at least one a-olefin having 2 to 20 carbon atoms other than propylene and have melting point below 80°C or do not show melting point as measured by a differential scanning calorimeter DSC. Here, the phrase "do not show melting point" means that the crystal melting peak with the heat of crystal melting of 1 J/g or more is not observed between -150 to 200°C. The measurement conditions are as those described in Examples. [0056] It is preferred that the propylene-based copolymer (B) used in the present invention has melting point of 60°C or less or does not show a melting point as measured by DSC, and more preferably does not show a melting point. [0057] In the propylene-based copolymer (B) of the present invention, an a-olefin used as a comonomer is preferably ethylene and/or an a-olefin having 4 to 20 carbon atoms. [0058] The propylene-based copolymer (B) of the present invention contains 45 to 92 mol% and preferably 56 to 90 mol% of a propylene unit, and 8 to 55 mol% and preferably 10 to 44 mol% of an a-olefin as a comonomer. [0059] The propylene-based copolymer (B) of the present invention desirably has the melt flow rate (MFR) of 0.01 to 1000 g/lOmin, and preferably 0.05 to 50 g/lOmin as measured at 230°C and under a load of 2.16 kg in accordance with ASTM D1238. [0060] As the method for producing the propylene-based copolymer (B) of the present invention, there is no particular restriction, but a publicly-known catalyst capable of performing stereoregular polymerization of olefins to afford isotactic or syndiotactic structures may be mentioned. For example it can be produced by copolymerizing propylene with other a-olefins in the presence of a catalyst composed of a solid titanium component and an organometallic compound as a main component, or a metallocene catalyst composed of a metallocene compound as one catalyst component. Preferably, as described later, it is produced by copolymerizing propylene, ethylene, and an a-olefin having 4 to 20 carbon atoms in the presence of a metallocene catalyst. For example, a catalyst described in International Publication WO 2004-087775, for example, such a catalyst described in Examples le to 5e in the pamphlet of said document and the like may be used. [0061] The propylene-based copolymer (B) of the present invention is preferred to have the following properties additionally and independently. [0062] Triad tacticity (mm fraction) as measured by 13C-NMR is preferably 85 % or more, more preferably 85 to 97.5 %, further preferably 87 to 97 %, particularly preferably 90 to 97%. When the triad tacticity (mm fraction) is within this range, the polymer has particularly excellent balance between flexibility and mechanical strength, so that it is suitable for the present invention. The mm fraction can be measured by the method described from the line 7 of page 21 to the line 6 of page 26 in the pamphlet of International Publication WO 2004-087775. [0063] Shore A hardness of the propylene-based copolymer (B) of the present invention is not particularly restricted, but usually in the range of 30 to 80, preferably 35 to 75. [0064] Further, the propylene-based copolymer (B) in the present invention has the stress (M100) at 100 %-strain of usually 4 MPa or less, preferably 3 MPa or less, and more preferably 2 MPa or less as measured at 23°C in accordance with JIS K6301 by using JIS3 dumbbell, the span distance of 30 mm and the tensile rate of 30 mm/min. When the M100 of a propylene-based copolymer (B) is in this range, it is excellent in flexibility, transparency, and rubber elasticity. [0065] The propylene-based copolymer (B) of the present invention has crystallinity of usually 20 % or less, and preferably 0 to 15 % as measured by X-ray diffraction. The propylene-based copolymer (B) of the present invention has a single glass transition temperature, and its glass transition temperature Tg as measured by a differential scanning calorimeter (DSC) is usually -10 °C or less, and preferably in the range of -15°C or less. When the glass transition temperature Tg of the propylene-based copolymer (B) of the present invention is in the above-mentioned range, it is excellent in cold resistance and low-temperature properties. [0067] The propylene-based copolymer (B) of the present invention, when there exists melting point (Tm, °C) in the endothermic curve of a differential scanning calorimeter (DSC) method, has the guantity of heat of fusion AH of usually 30 J/g or less and is also subject to the following equation between C3 content (mol%) and the quantity of heat of fusion AH (J/g). AH < 345Ln(C3 content mol%) - 1492, here, when there is a melting point, 70 (1) Melting point and confirmation of presence or absence of the endotherm at 140°C or more 1-1) Melting point From the measured exothermic and endothermic curves, the maximum melting peak temperature during heating was taken as Tm. The measurement was performed as follows: after a sample was packed in an aluminum pan, (i) it was heated to 200°C at a heating rate of 100°C/min and kept at 200°C for 5 minutes, (ii) cooled to -150°C at 20°C/min, and then (iii) heated to 200°C at a heating rate of 20°C/min. The temperature at the endothermic peak observed in the above (iii) was taken as Tm. [0164] 1-2) Confirmation of presence or absence of the endotherm at 140°C or more (see Figure 1) Dried alumina packed in the same aluminum pan as the one described above in 1-1) was prepared as the reference, and then the vertical axis value (heat quantity) of the endothermic curve in (iii) obtained by the measurement according to the conditions of the above-mentioned 1-1) was taken as follows. [0165] Dtop - the vertical axis value at the peak position of melting point (maximum melting point) Di4o°C = the vertical axis value at 140°C Di5o°C = the vertical axis value at 150°C From these values, Dl and D2 defined as below were calculated to confirm whether they satisfy Equation (1) or not. [0166] Dl = Dtop - D150°C D2 = D140°C - D150°C D2/D1<0.05 Equation (1) (2) Contents of comonomers (ethylene, 1-butene) They were measured by the 13C-NMR spectrum analyses. [0167] (3) MFR MFR was measured at 190°C or 230°C under a load of 2.16 kg in accordance with ASTM D1238. [0168] (4) Vicat softening temperature The measurement was performed in accordance with ASTM D1525 . [0169] (5) Density The density was measured in accordance with the method described in ASTM 1505. [0170] (6) Shore A hardness A sample sheet with 2 mm thickness was kept at room temperature for 48 hours after the measurement, then it was contacted with a push pin of A-type instrument to read the scale immediately (in accordance with ASTM D2240). [0171] (7-1) Tensile modulus (a propylene-based polymer (A)) The measurement was performed at 23°C with the chuck distance of 80 mm and tensile rate of 200 mm/min by using a dumbbell in accordance with JIS K7113-2. The sample for the measurement was the press sheet that was obtained by hot-pressi'ng a sample at 190°C between the upper and the lower SUS molds with 4-mm thickness, then rapidly cooling it with a cooling chiller of 20°C for molding, then leaving it for 72 hours or longer. [0172] (7-2) Tensile modulus (a propylene-based copolymer (B)) The measurement was performed at 23°C with the span distance of 30 mm and tensile rate of 200 mm/min by using a JIS3 dumbbell in accordance with JIS K6301. [0173] The sample for the measurement was the press sheet that was obtained by hot-pressing a sample at 190°C between the upper and the lower SUS molds with 4-mm thickness, then rapidly cooling it with a cooling chiller of 20°C for molding. (8) Molecular weight distribution (Mw/Mn) The measurement was performed by a Gel Permeation Chromatography (GPC) at the column temperature of 140°C by using an o-dichlorobenzene solvent (mobile phase) (Mw; weight-average molecular weight, Mn; number-average molecular weight, relative to polystyrene standards). Specifically, the molecular weight distribution was measured by using a gel permeation chromatograph Alliance GPC-2000 manufactured by Waters Corporation in the following manner. Separation columns : two TSKgel GNH6-HT columns and two TSKgel GNH6-HTL columns, all having a column diameter of 7. 5 mm and a column length of 300 mm; column temperature: 140°C; mobile phase: an o-dichlorobenzene (Wako Pure Chemical Industries, Ltd.) containing 0.025 % by weight of BHT (Takeda Pharmaceutical Co., Ltd.) as an antioxidant; moving rate: 1.0 mL/min; sample concentration: 15 mg/10-milliliters; injection volume: 500 microliters; detector: a differential refractometer; standard polystyrenes: polystyrene with Mw<1000 and Mw>4xl06 manufactured by Tosoh Corp., and polystyrene with 1000