CN106030828B - Stacked film, solar module backboard and solar module - Google Patents

Abstract

The problem of the present invention is to provide a kind of stacked film, solar module backboard and solar module with hydrolytic resistance and both disguised properties of visible ray.According to the present invention, a kind of stacked film is provided, the stacked film at least has the 1st layer and the 2nd layer containing polyester containing polyester and Chinese white, wherein, above-mentioned 1st layer is in contact with above-mentioned 2nd layer of at least one face, and above-mentioned 1st layer of Chinese white density is 1.0 × 10^‑4~1.0 × 10^‑3g/cm², above-mentioned 2nd layer of thickness is 100~300 μm, and the overall Chinese white concentration of above-mentioned stacked film is more than 0 mass % and less than 2 mass %, and the overall end carboxy concentration of above-mentioned stacked film is 6~30 equivalents/ton.

Description

Stacked film, solar module backboard and solar module

Technical field

The present invention relates to a kind of stacked film, solar module backboard and solar module.

Background technology

Polyester film is cheap and has excellent characteristic, therefore can be used in multiple fields.For needed for polyester film Performance is various.For example, when polyester film is used for into the article that diaphragm used for solar batteries etc. uses for a long time out of doors, Require higher hydrolytic resistance to maintain intensity for a long time, and require from the viewpoint of design it is higher can See light disguise.

Thus, for example having recorded a kind of laminated polyester film in patent document 1, the laminated polyester film is by including 10 The substrate layer of the top layer of~30 weight % Titanium particles and Titanium particles comprising 0.1~4 weight % is formed, and film Titanium particles containing ratio in entirety is 3~8 weight %.Also, a kind of polyester film is recorded in patent document 2, institute Stating polyester film, there is the outermost layer at least one layer to configure multilayer of the inorganic particles concentration containing layer containing inorganic particles Structure, and the content of the inorganic particles in polyester film entirety is 2~10 mass %.

Conventional art document

Patent document

Patent document 1：No. 2010/113920 pamphlet of International Publication

Patent document 2：No. 5288068 publications of Japanese Patent No.

The summary of invention

The invention technical task to be solved

The visible ray disguise of polyester film can be improved by adding Chinese white in polyester film.However, In the process that Chinese white is circulated to the polyester in polyester film manufacture, sent out sometimes through contained moisture in Chinese white Raw poly- ester hydrolysis, and by the shearing by white pigment particle and the thermal decomposition of caused heating, sometimes generation polyester. Accordingly, there exist the molecular weight that Chinese white concentration then polyester is more improved for the purpose of improving visible ray disguise more to decline, and resistance to The problem of water-disintegrable decline.Due to this reason, it is difficult to produce and possess hydrolytic resistance and both disguised properties of visible ray Polyester film.

The polyester film of patent document 1 improves visible ray disguise by top layer, and is improved by substrate layer water-fast Xie Xing, it thus can realize that hydrolytic resistance and visible ray are disguised simultaneously.But the titanium oxide concentration of film entirety is 3~8 weights Measure % and higher, therefore visible ray disguise is excellent, but can not say that hydrolytic resistance is abundant.The polyester film of patent document 2 will be thin The content of the overall inorganic particles of film is set to 2~10 mass %, comes to realize light reflectivity and hydrolytic resistance simultaneously with this.But The content of the overall inorganic particles of film is higher for 2~10 mass %, therefore visible ray disguise is excellent, but can not say water-fast Solution property is abundant.

The present invention completes to solve above-mentioned problem, and it will provide a kind of hidden with hydrolytic resistance and visible ray The stacked film of both properties of property is as the problem that should be solved.And the present invention will provide one kind and include above-mentioned stacked film, the sun Can battery module be used as the problem that should be solved by the use of backboard and solar module.

For solving the means of technical task

The present inventor etc. have found to solve the result that above-mentioned problem is furtherd investigate, at least having containing polyester and The 1st layer of Chinese white and the 2nd layer containing polyester, and in the 1st layer of stacked film being in contact with the 2nd layer of at least one face, By making the 1st layer of Chinese white density, the overall Chinese white concentration of the 2nd layer of thickness, stacked film and stacked film overall End carboxy concentration meets defined condition respectively, can take into account excellent hydrolytic resistance and excellent visible ray is disguised.This Invention is completed based on these results of study.

Specifically, the present invention has following structure.

<1>A kind of stacked film, it at least has the 1st layer and the 2nd layer containing polyester containing polyester and Chinese white, In the stacked film,

1st layer is in contact with the 2nd layer of at least one face,

1st layer of Chinese white density is 1.0 × 10^-4~1.0 × 10^-3g/cm²,

2nd layer of thickness is 100~300 μm,

The overall Chinese white concentration of stacked film is more than 0 mass % and is less than 2 mass %,

The overall end carboxy concentration of stacked film is 6~30 equivalents/ton.

<2>According to<1>Described stacked film, wherein, the 1st layer of Chinese white concentration is 5~20 mass %.

<3>According to<1>Or<2>Described stacked film, wherein, the 1st layer of thickness is 5~50 μm.

<4>According to<1>~<3>Stacked film described in middle either a program, wherein, the 2nd layer of Chinese white concentration for 0~ 1.5 mass %.

<5>According to<1>~<4>Stacked film described in middle either a program, wherein, contain 60 as raw material in the 2nd layer Below the quality % recovery fragment that the width end of stacked film is trimmed and crushed, do not wrap actually in the 1st layer The fragment containing recovery.

<6>According to<1>~<5>Stacked film described in middle either a program, wherein, the stacked film is used for solar cell Module.

<7>A kind of solar module backboard, it is included<1>~<6>Stacked film described in middle either a program.

<8>A kind of solar module, it is included<7>Described solar module backboard.

Invention effect

According to the present invention, there is provided a kind of stacked film with hydrolytic resistance and both disguised properties of visible ray.And According to the present invention, there is provided a kind of solar module back of the body with hydrolytic resistance and both disguised properties of visible ray Plate.Further according to the present invention, there is provided a kind of solar energy of the stacked film comprising the present invention or solar module backboard Battery module.

Brief description of the drawings

Fig. 1 is the sectional view of one of the structure for representing the stacked film of the present invention.

Fig. 2 is other sectional views for the structure for representing the stacked film of the present invention.

Embodiment

Hereinafter, it is described in detail for the present invention.The explanation of described constitutive requirements is according to representational below Embodiment and concrete example and complete, the present invention is not limited to this embodiment.In addition, "~" table is used in this specification The number range shown refers to the scope for being included numerical value described before and after "~" as lower limit and higher limit.

<Stacked film>

The stacked film of the present invention at least has the 1st layer and the 2nd layer containing polyester containing polyester and Chinese white, described Stacked film is characterised by that above-mentioned 1st layer is in contact with above-mentioned 2nd layer of at least one face, and above-mentioned 1st layer of Chinese white is close Spend for 1.0 × 10^-4~1.0 × 10^-3g/cm², above-mentioned 2nd layer of thickness is 100~300 μm, the overall white of above-mentioned stacked film Pigment concentration is more than 0 mass % and less than 2 mass %, and the overall end carboxy concentration of above-mentioned stacked film is 6~30 equivalents/ton.

By being set to this structure, hydrolytic resistance and both disguised properties of visible ray can be realized.On with resistance to The mechanism of both disguised properties of water-disintegrable and visible ray, can infer as follows.I.e. it can be extrapolated that by by Chinese white concentration Relatively low layer comes to the 2nd layer of imparting high hydrolytic resistance, and by regarding the higher layer of Chinese white concentration as the 1st as the 2nd layer Layer to assign the 1st layer high visible disguise, and the Rotating fields by being set to layers 1 and 2 being laminated are and energy It is enough to realize that hydrolytic resistance and visible ray are disguised simultaneously.In detail, deducibility：By the way that the 1st layer of Chinese white density is set to 1.0×10^-4~1.0 × 10^-3g/cm², it is disguised that good visible ray can be achieved；By by the 2nd layer of thickness for 100~ 300 μm, the overall Chinese white concentration of stacked film is set to be less than 2 mass %, and by the end carboxy concentration of stacked film entirety 6~30 equivalents/ton is set to, good hydrolytic resistance can be achieved.

The stacked film of the present invention at least has the 1st layer and the 2nd layer containing polyester containing polyester and Chinese white, and the 1 layer is in contact with the 2nd layer of at least one face.

Fig. 1 is illustrated in by the one of the stacked film of the present invention.Stacked film shown in Fig. 1 is formed by the 1st layer 12 and the 2nd layers 10 Double-decker stacked film, the 1st layer is in contact with the 2nd layer of a face.Also, the present invention stacked film be not limited to as The stacked film of the double-decker of one is shown in Fig. 1, can also one as shown in Figure 2 like that, be with the 1st layer the 12, the 2nd The stacked film of the three-decker for the order stacking that 10 and the 1st layer 12 of layer.In addition, the stacked film of the present invention can also be stacked gradually There are the 1st layer, the 2nd layer and the stacked film of other layers.

When stacked film is used as the purposes for being bonded and using with different materials such as solar cell backboards, if binding face is white Color pigment concentration is larger, then cementability is poor and easily peelable, therefore is preferably the double-decker being made up of layers 1 and 2.

Hereinafter, each layer of the stacked film of the present invention is illustrated.

<1st layer>

1st layer contains polyester and Chinese white, and Chinese white density is 1.0 × 10^-4~1.0 × 10^-3g/cm².Also, the 1 layer is in contact with the 2nd layer of at least one face.

1st layer of Chinese white density is 1.0 × 10^-4~1.0 × 10^-3g/cm², preferably 1.0 × 10^-4~7.0 × 10^-4~g/cm², more preferably 1.5 × 10^-4~6.0 × 10^-4g/cm².By the 1st layer of Chinese white density is set to 1.0 × 10^-4g/cm²More than, it is possible to increase visible ray is disguised, by being set to 1.0 × 10^-3g/cm²Below, it is possible to increase hydrolytic resistance.

1st layer of Chinese white density is the ginseng determined by Chinese white concentration contained in the 1st layer of thickness and the 1st layer Number, specifically, can be by being calculated with following formula.

D=t × ρ × C × 10^-6

Herein,

Chinese white density：D g/cm²

Chinese white concentration：C mass %

1st thickness degree：tμm

1st layer of density：ρg/cm³。

Contained Chinese white concentration is preferably 5~20 mass % in 1st layer, more preferably 5~15 mass %, further Preferably 6~12 mass %.By being set to that sufficient visible ray disguise more than 5 mass % can be obtained, by being set to 20 matter Amount below % can improve hydrolytic resistance.

1st layer of Chinese white concentration is by the ratio of the quality of shared Chinese white in the quality of the 1st layer of entirety Parameter expressed as a percentage, specifically, it can determine by the following method.That is, in crucible, by the 1st in stacked film Layer takes 3g as measure sample, and with 900 DEG C of heating for carrying out 120 minutes in electric oven.After being cooled down afterwards in electric oven Crucible is taken out, and determines the quality of the ash content remained in crucible.The ash content is Chinese white powder, by the quality of ash content divided by survey The quality for determining sample and be multiplied by 100 value as Chinese white concentration.

1st layer of thickness has no particular limits, for example, 1~100 μm, preferably 5~50 μm, more preferably 10~50 μm, more preferably 30~50 μm.Visible ray disguise can be improved if the 1st layer of thickness is more than 5 μm, if 50 μm Hydrolytic resistance can be then improved below.

<2nd layer>

2nd layer contains polyester.2nd layer of thickness be 100~300 μm, more preferably 200~300 μm, further preferably For 200~250 μm.Sufficient hydrolytic resistance can be obtained by the way that thickness is set into more than 100 μm, by being set to less than 300 μm, life Yield uprises, more economical.

On polyester contained in the 2nd layer, and polyester contained in the 1st layer can be identical, also can be different.

2nd layer can contain Chinese white, can also not contain.When containing Chinese white in the 2nd layer, institute in the 1st layer Contained Chinese white can be identical in the Chinese white contained and the 2nd layer, also can be different.

When containing Chinese white in the 2nd layer, Chinese white concentration is preferably 0~1.5 mass %, and more preferably 0~1 Quality %, is not contained actually further preferably.Do not contain actually and refer to wrap in the range of the effect of the present invention is not influenceed Contain, such as represent below 0.1 mass %.

<Polyester>

Polyester for the 1st layer and the 2nd layer has no particular limits, such as can enumerate by aromatic acid or its ester shape Become second nature derivative and glycol or the line style saturated polyester of its ester formative derivative synthesis.

As the concrete example of polyester, can enumerate PET (PET), polyethylene terephthalate, Polybutylene terephthalate (PBT), poly- (terephthalic acid (TPA) Isosorbide-5-Nitrae-cyclohexane dicarboxylates), poly- NDA second diester Deng.Wherein, from the point of view of the balance this point of mechanics physical property and cost, more preferably PET or poly- 2,6- naphthalenes Dioctyl phthalate second diester, particularly preferred PET.

Above-mentioned polyester can be homopolymer, or copolymer.Moreover, it can also mix other species on a small quantity in above-mentioned polyester Resin, such as polyimides etc..

In polymeric polyester, from the viewpoint of carboxyl-content is suppressed below prescribed limit, preferably by Sb systems, Ge System, the compound of Ti systems are used as catalyst, wherein particularly preferred Ti based compounds.When using Ti based compounds, preferably pass through By Ti based compounds in more than 1ppm and below 30ppm scope, more preferably in more than 3ppm and below 15ppm scope As catalyst come the mode that is polymerize.If the ratio of Ti based compounds is within the above range, terminal carboxyl group can be contained Amount is adjusted to scope described later, can remain the hydrolytic resistance of polymer relatively low.

It can be applicable in the synthesis of polyester of Ti based compounds has been used for example in Japanese Patent Publication 8-301198 Number publication, Japanese Patent No. 2543624, Japanese Patent No. 3335683, Japanese Patent No. 3717380, Japanese Patent No. No. 3897756, Japanese Patent No. 3962226, Japanese Patent No. 3979866, Japanese Patent No. 3996871, Japan specially Profit the 4000867th, Japanese Patent No. 4053837, Japanese Patent No. 4127119, Japanese Patent No. No. 4134710, day Method described in this patent the 4159154th, Japanese Patent No. 4269704, Japanese Patent No. 4313538 etc..

The carboxyl-content of each polyester in 1st layer and the 2nd layer is preferably more preferably 20 equivalents/ton below 35 equivalents/ton Hereinafter, below especially preferably 17 equivalents/ton.

If the carboxyl-content of polyester be 35 equivalents/ton below, hydrolytic resistance can be kept, can by it is damp and hot through when after Intensity decline is suppressed to smaller.The lower limit of carboxyl-content is from the point of view of this point of cementability is kept, preferably 2 equivalents/ton.Separately Outside, in this manual, " equivalent/ton " represents the molar equivalent of every 1 ton (1000kg).

Carboxyl-content (AV) is the value determined by the following method.That is, after polyester 0.1g being dissolved in into phenmethylol 5ml, Add in the mixed solution of 5ml chloroforms and instill phenolic red indicator, to it with benchmark liquid (0.01N KOH- phenmethylols mixed solution) Titrated.The concentration of terminal carboxyl group " equivalent/ton " is calculated by the infusion volume.

Carboxyl-content in polyester can be carried out by polymerization catalyst species, film forming condition (film temperature and time) Adjustment.

Form the 1st layer or the 2nd layer of polyester preferably solid phase after polymerisation.Thereby, it is possible to reach preferable carboxyl to contain Amount.Solid phase can be that continuity method (makes to be full of resin in tower, and while heating carried out to it while making it fully be detained regulation The method sent out after time), or batch process (putting into resin in a reservoir, and the method for heating the stipulated time).Specifically Ground, Japanese Patent No. 2621563, Japanese Patent No. 3121876, Japanese Patent No. can be applicable in solid phase No. 3136774, Japanese Patent No. 3603585, Japanese Patent No. 3616522, Japanese Patent No. 3617340, Japan specially Method described in profit the 3680523rd, Japanese Patent No. 3717392, Japanese Patent No. 4167159 etc..

The temperature of solid phase be preferably more than 170 DEG C and less than 240 DEG C, more preferably more than 180 DEG C and 230 DEG C with Under, more preferably more than 190 DEG C and less than 220 DEG C.Also, solid state polymerization time is preferably more than 5 hours and 100 hours Hereinafter, more preferably more than 10 hours and less than 75 hours, more preferably more than 15 hours and less than 50 hours.Solid polycondensation Conjunction is preferably carried out in a vacuum or under nitrogen atmosphere.

1st layer or the 2nd layer is after above-mentioned polyester for example is carried out into melting extrusion with film-form, to be roused using curtain coating (casting drum) is allowed to cool solidification non-stretched film is made, and by the non-stretched film at Tg~(Tg+60) DEG C The stretching of 1 time or more than 2 times is carried out in a manner of total multiplying power is turned into 3 times~6 times along long side direction, afterwards in Tg~(Tg+ DEG C 60) biaxially oriented film stretched in the width direction in a manner of multiplying power turns into 3~5 times at.

Furthermore, it is possible to the heat treatment of 1~60 second is carried out at 180~230 DEG C as needed.

1st layer can carry out such as corona for the face of side opposite with the face of the side at least provided with the 2nd layer as needed Processing, flame treatment, glow discharge process etc. are surface-treated.In Corona discharge Treatment, generally with carrying out overlay film to derivative Metallic roll (dielectric roller) insulation electrode between apply high frequency, high pressure generates the insulation breakdown of interelectrode air, thus Make interelectrode air ionization, and corona discharge is produced between electrode.Also, by making polymeric substrate pass through corona discharge Between come carry out.

As preferable treatment conditions, 1~3mm of gap clearance of preferred electrode and dielectric roller, frequency 1~ 100kHz, apply energy 0.2~5kVA minutes/m²Left and right.

Glow discharge process is the method that also referred to as vacuum plasma treatment or low pressure plasma are handled, and is to pass through The method that electric discharge in the gas (plasma gas) of low pressure atmosphere produces plasma to handle substrate surface. In the processing of the present invention low pressure plasma that uses be plasma gas it is relatively low in pressure under conditions of generate it is non-flat Weigh plasma.The processing of the present invention is entered by placing processed film (polymeric substrate) in the low pressure plasma atmosphere OK.

In glow discharge process, as the method for producing plasma, direct current glow discharge, high frequency can be utilized to put The methods of electricity, microwave discharge.The power supply used in electric discharge can be that direct current is alternatively exchange.During using exchange, preferably 30Hz~ 20MHz or so scope.During using exchange, 50 or 60Hz commercial frequency can be used, it is possible to use 10~50kHz or so height Frequently.Also, the it is preferred that method of the high frequency using 13.56MHz.

As the plasma gas used in glow discharge process, can use oxygen, nitrogen, vapor, argon gas, The inorganic gas such as helium, the mixed gas of particularly preferred oxygen or oxygen and argon gas.And specifically, it is preferable to use oxygen and argon gas Mixed gas.When using the mixed gas of oxygen and argon gas, as both ratios, oxygen is calculated as with intrinsic standoff ratio: argon gas= 100: 0~30: 70, more preferably 90: 10~70: 30.Also, do not introduce gas into process container particularly preferably, But plasma will be used as by leaking into the gas such as the air in process container or the vapor come out from treated object The method of body gas.

Pressure as plasma gas is, it is necessary to may achieve the low pressure of nonequilibrium plasma condition.As specific The pressure of plasma gas be preferably 0.005~10Torr (0.666~1333Pa) left and right scope, more preferably 0.008 The scope of~3Torr (1.067~400Pa) left and right.Cementability is improved if being more than 0.666Pa if the pressure of plasma gas Effect is abundant, can then suppress to make electric discharge become unstable phenomenon because electric current increases if below 1333Pa.

As plasma output, according to the shapes and sizes of process container, shape of electrode etc., can not lump together, But preferably 100~2500W or so, more preferably 500~1500W or so.

The processing time of glow discharge process is preferably 0.05~100 second, more preferably 0.5~30 second or so.If processing Time is that then can fully obtain cementability improved effect in more than 0.05 second, and processed film can be then prevented if less than 100 seconds Deformation and coloring etc..

The discharge process intensity of glow discharge process depends on plasma output and processing time, preferably 0.01~ 10kVA minutes/m²Scope, more preferably 0.1~7kVA minutes/m²Scope.

By the way that discharge process intensity is set into 0.01kVA minutes/m²More than, it can obtain sufficient cementability improvement effect Fruit, by being set to 10kVA minutes/m²Hereinafter, deformation or this problem of coloring of processed film can be avoided.

In glow discharge process, it is also preferred that being heated in advance to processed film.With it, with without heating When compare, good cementability can be obtained with the short time.Heating-up temperature is preferably the softening temperature+20 of the 40 DEG C~film that is processed DEG C scope, the scope of the softening temperature of more preferably 70 DEG C~processed film., can by the way that heating-up temperature is set into more than 40 DEG C Obtain the improved effect of sufficient cementability.Also, can by the way that heating-up temperature is set to below the softening temperature of processed film The good treatability of film is ensured in processes.

As the specific method for the temperature for improving processed film in a vacuum, adding based on infrared heater can be enumerated Heating hot, based on the contact with hot-rolling etc..

As flame treatment, such as the flame treatment using the flame for having imported silane compound can be enumerated.

On the 2nd layer of polyester, as the form of material resin, particle, fine hair, their mixture etc. can be used, And the quality ratio of fine hair is preferably set to less than 60% to be mixed with particle.By the way that so particle and fine hair are mixed Close to use, the melting or thermal history of material resin can be adjusted.Fine hair is, for example, to be crushed unwanted film And as the smashing thing of small pieces (so-called fragment) or piece bits etc., i.e., the width end of stacked film is trimmed, crushed Recovery fragment.Recovery ratio can be improved by improving fine hair ratio, and can reduce the cost of raw material.On the other hand, fine hair ratio Rate increase can increase volume, bulk density with for example only have particle when compared to decline.As the resin for obtaining fine hair Film, it is adapted to polyester film, the preferably film with the polyester of the polyester resin identical type in material resin.By by fine hair Ratio is set to below 60 mass %, can suppress relatively low by the amplitude of fluctuation of the end COOH amounts of the polyester film obtained. Wherein, due to it is identical the reasons why, the quality ratio of fine hair is preferably more preferably 10~50 mass % below 60 mass %, especially It is preferably 30~50 mass %.

As the size of fine hair, as long as then being had no particular limits in the range of Volume Changes are endowed, preferred fine hair Thickness be 20~5000 μm.Wherein, from by bulk density become too small and fullness rate will not excessive descent mode From the viewpoint of to avoid melting deficiency, preferred scope of the thickness of fine hair at 100~1000 μm, more preferably 100~500 μm Scope.

Also, from the point of view of the end COOH amounts for the polyester film produced more decline this point, the preferred size of fine hair Deviation is smaller, such as the deviation of the thickness of preferred fine hair is within ± 100%, within more preferably ± 50%, further preferably Within ± 10%.When using fine hair, by the way that thickness equidimension deviation to be suppressed to smaller, will can be obtained polyester The variation of the end COOH amounts of film is suppressed to relatively low.

As the bulk density of fine hair, in the range of the bulk density of material resin meets above range, preferably 0.3 ~0.7 scope.The bulk density of material resin refers to medium into the container for being about to powder with steady state and being put into constant volume After processing, volume by the quality for the powder for being set to regulation shape divided by now and the proportion (matter of per unit volume obtained Amount), bulk density more small size is bigger.

Additionally, it is preferred that the 1st layer does not include recovery fragment actually.Do not include actually and refer to do not influenceing the effect of the present invention Include, such as represented below 0.1 mass % in the range of fruit.

<Chinese white>

1st layer contains Chinese white.Also, the 2nd layer can contain Chinese white, can also not contain.By making the 1st layer In improve the reflectivity of light (whiteness) containing Chinese white, and visible ray disguise is improved, thus, it is possible to assign design. Further, it is possible to improve the reflectivity (whiteness) of light, and improve the generating efficiency of solar cell.

The average grain diameter for forming the particle (hereinafter referred to as " particle ") of Chinese white is not particularly limited, but preferably 0.1 The particle of the particle of~10 μm of particle, more preferably 0.1~5 μm, more preferably 0.15~1 μm.If particle is averaged Particle diameter is 0.1~10 μm, then also the whiteness of film can be set into more than 50 even if for less addition.

In addition, the average grain diameter of particle can be obtained by electron microscope method, specifically can be by the following method Obtain.

Particle is observed with scanning electron microscope, according to the suitably sized change multiplying power of particle, and by the photograph of shooting Piece is amplified duplication.Then, the particle for randomly selected at least more than 200, the periphery of each particle is tracked. By image analysis apparatus, by these tracing figure pictures to determine the equivalent circle diameter of particle, and their average value is set to flat Equal particle diameter.

Particle can be any of inorganic particulate or organic filler, can also be used in combination both.Thus, the anti-of light can be improved Penetrate rate and improve the generating efficiency of solar cell.As the inorganic particulate preferably used, such as wet type and dry type can be used Silica, cataloid, calcium carbonate, alumina silicate, calcium phosphate, aluminum oxide, magnesium carbonate, zinc carbonate, titanium oxide, zinc oxide (zinc white), antimony oxide, cerium oxide, zirconium oxide, tin oxide, lanthana, magnesia, barium carbonate, basic lead carbonate (white lead), sulfuric acid Barium, calcium sulfate, lead sulfate, zinc sulphide, mica, mica titanium, talcum, clay, kaolin, lithium fluoride and calcirm-fluoride etc., it is especially excellent Select titanium dioxide, barium sulfate.In addition, titanium oxide can be any of Detitanium-ore-type, rutile-type.Also, can be to particle table The inorganic processing of aluminum oxide or silica etc. is implemented in face, can also implement the organic process of silicon systems or alcohol system etc..

The preferred titanium dioxide in these particles, thus can also play excellent durability under the irradiation of light.Specifically Ground, 63 DEG C, 50%Rh, exposure intensity 100mW/cm²When the lower UV for carrying out 100 hours irradiates, extension at break conservation rate is preferred For more than 35%, more preferably more than 40%.The light that polyester can also be suppressed thus by the irradiation of light is decomposed and deteriorated, therefore more It is suitable as the back protection film of solar cell used out of doors.

Rutile-type and Detitanium-ore-type in titanium dioxide be present, but preferably add in the polyester based on rutile-type TiO 2 particles.The spectral reflectance of the ultraviolet of Detitanium-ore-type is very big, in contrast, rutile-type has ultraviolet suction The characteristic of yield larger (spectral reflectance is smaller).This light splitting that the present inventor is conceived in the crystal habit of titanium dioxide is special The difference of property, finds the UV absorbing properties by using rutile-type, can be in rear surface of solar cell protection polyester Light resistance is improved in film (backboard used for solar batteries).Even if other ultra-violet absorbers are not thus added actually, in light Film durability under irradiation is also excellent.Therefore, it is not easy to produce because of oozing out for ultra-violet absorber under pollution or adhesiveness Drop.

In addition, as described above, it is preferred to TiO 2 particles based on rutile-type, " main body " mentioned here means Rutile titanium dioxide amount in whole TiO 2 particles is more than 50 mass %.

Also, it is preferred that the anatase titanium dioxide amount in whole TiO 2 particles is below 10 mass %.More preferably For below 5 mass %, especially preferably 0 mass %.If the content of anatase titanium dioxide exceedes above-mentioned higher limit, entirely Shared rutile titanium dioxide amount is reduced in TiO 2 particles, therefore UV absorbing properties become insufficient sometimes, Further, since the photocatalysis of anatase titanium dioxide is stronger, therefore inclining for light resistance decline is also had by the effect To.Rutile titanium dioxide and anatase titanium dioxide can enter according to x-ray structure diffraction or light splitting absorption characteristic Row difference.

Rutile titanium dioxide particle can implement the inorganic processing of aluminium dioxide or silica etc. to particle surface, The organic process of silicon systems or alcohol system etc. can also be implemented.Rutile titanium dioxide can be matched with polymer blend it Before, the adjustment of particle diameter and the removal of oversize grain are carried out using purifying technique.As the industrial mechanism of purifying technique, pulverizer Structure can for example apply aeropulverizer, ball mill, as classification mechanism, such as can apply dry-type centrifugal separation or the centrifugation of wet type Separation.

In the present invention organic filler can also be used as Chinese white.It is preferred that the resistance to hot grain in polyester film-forming process Son, such as using the particle being made up of crosslinked resin, can specifically use with polystyrene of divinyl benzene crosslinked etc.. The size or addition of particle are identical with the situation of inorganic particulate.

As the known method used when adding particle in polyester film, can use all the time known various Method.As its exemplary process, following methods can be enumerated.

(A) ester exchange reaction when PET synthesizes or esterification add particle before terminating, or The method that particle is added before polycondensation reaction starts.

(B) particle, and the method for carrying out melting mixing are added in PET.

(C) above-mentioned (A), (B) method in manufacture the master batch (or also referred to as masterbatch (MB)) of the particle largely added, and The PET for not containing they and particle is kneaded, so as to the method for the particle containing ormal weight.

(D) method for directly using the master batch of above-mentioned (C).

Wherein, mother material (the MB methods preferably in advance mixed polyester and particle using extruder：Above-mentioned (C)).And And can use and in advance put into undried polyester resin and particle in extruder, and while moisture and air etc. are entered Row degassing, while making MB method.A small amount of polyester resin is further preferably at least dried in advance to make MB method, this The acid number that polyester can be suppressed rises.Deaerated at this point it is possible to enumerate while the method extruded, or do not deaerate and by fully dry Method that dry polyester resin is extruded etc..

For example, make the polyester put into during MB preferably reduces moisture rate beforehand through drying.As drying condition, preferably In 100~200 DEG C, dry more preferably in 120~180 DEG C more than 1 hour, more preferably dry more than 3 hours, it is further excellent Choosing is dried more than 6 hours.Thus, below 50ppm is preferably turned into the amount of moisture of polyester resin, more preferably as below 30ppm Mode fully dry.The method of premixing is not particularly limited, and be may be based on method in batches, be may also rely on uniaxially or biaxially Mixing extruder above.Deaerated it is preferred that using while at 250 DEG C~300 DEG C, preferably 270 DEG C~280 when making MB Molten polyester resin at a temperature of DEG C, 1 degassing mouth for being preferably provided with more than 2 is set in preparation kneading machine, carried out More than 0.05MPa more preferably carries out more than 0.1MPa continuous attraction degassing, and the method for maintaining the decompression in mixer etc..

<Other materials>

It can use in the 1st layer in addition to polyester and Chinese white, and also add in addition to polyester in the 2nd layer Add end-capping reagent, the material of hydrolytic resistance (weatherability) is improved with this.Moreover, in the range of the effect of the present invention is not hindered, Various additives can be added in the 1st layer and/or the 2nd layer, such as phase solvation, plasticizer, weather resisting agent, antioxidant, heat are surely Determine agent, lubricant, antistatic additive, brightening agent, colouring agent, conductive agent, ultra-violet absorber, fire retardant, flame retardant and dyestuff Deng.

(end-capping reagent)

1st layer and/or the 2nd layer can contain 0.1~10 mass % relative to the gross mass of polyester resin and polyester resin End-capping reagent.0.2~5 matter is more preferably relative to the above-mentioned addition of the end-capping reagent of the gross mass for the polyester resin for forming polyester Measure %, more preferably 0.3~2 mass %.

Poly- ester hydrolysis passes through the H as caused by terminal carboxylic etc.⁺The catalytic effect of (proton) and be accelerated, therefore in order to carry High hydrolytic resistance (weatherability), it is effective to add with the end-capping reagent of terminal carboxylic's reaction.

If the addition of end-capping reagent is more than 0.1 mass % relative to the gross mass of polyester resin, weatherability is easily found Effect is improved, if below 10 mass %, then can suppress end-capping reagent and be had an effect relative to polyester as plasticizer, therefore can Suppress the decline of mechanical strength and heat resistance.

As end-capping reagent, epoxide, carbodiimide compound, oxazoline compounds, carbonate products can be enumerated Deng the carbodiimide that preferably higher with the compatibility of PET (PET) and end-blocking can be higher.

End-capping reagent (especially carbodiimide end-capping reagent) is preferably HMW.Thus, it is possible to during reducing melted masking Volatilization.Molecular weight is preferably 200~100,000, more preferably 2000~80,000, more preferably 10,000~50,000.If end-capping reagent The molecular weight of (especially carbodiimide end-capping reagent) is then easily uniformly dispersed and become easily fully in the polyester within the above range It was found that weatherability improved effect, also, it is not volatile in extrusion, film-forming process, and easily find that weatherability improves effect.

In addition, the molecular weight of end-capping reagent refers to weight average molecular weight.

(carbodiimide system end-capping reagent)

Carbodiimide compound with carbodiimide has mono-functional's carbodiimide and multi-functional carbodiimide, makees For mono-functional's carbodiimide, dicyclohexylcarbodiimide, DIC, dimethyl carbodiimide, two can be enumerated Isobutyl group carbodiimide, dioctyl carbodiimide, ter /-butylisopropyl carbodiimide, diphenyl carbodiimide, di-t-butyl carbon Diimine and two-betanaphthyl carbodiimide etc..Particularly preferred dicyclohexylcarbodiimide or DIC.

Also, as multi-functional carbodiimide, preferably using the carbodiimide that the degree of polymerization is 3~15.Specifically, can Exemplify 1,5- naphthalenes carbodiimide, 4,4 '-diphenyl methane carbodiimide, 4,4 '-diphenyldimethyhnethane carbodiimide, 1, 3- phenylenes carbodiimide, Isosorbide-5-Nitrae-phenylene vulcabond, 2,4- toluene carbodiimide, 2,6- toluene carbodiimide, 2,4- The mixture of toluene carbodiimide and 2,6- toluene carbodiimide, hexa-methylene carbodiimide, hexamethylene-Isosorbide-5-Nitrae-carbodiimide, Xylyl carbodiimide, isophorone carbodiimide, dicyclohexyl methyl hydride -4,4 '-carbodiimide, hexahydrotoluene carbon two are sub- Amine, tetramethyl xylylen carbodiimide, 2,6- diisopropyl phenyls carbodiimide and 1,3,5- triisopropylbenzene -2,4- carbon Diimine etc..

Carbodiimide compound can produce isocyanates system gas, therefore the preferably higher carbon of heat resistance by thermal decomposition Diimine compounds.In order to improve heat resistance, molecular weight (degree of polymerization) is more high more preferred, more preferably by carbodiimide compound End is set to the higher structure of heat resistance.Also, easily cause further thermal decomposition if thermal decomposition is caused, therefore need The extrusion temperature of polyester is set to compared with time such as low temperature as far as possible.

The carbodiimide of end-capping reagent is it is also preferred that with cyclic structure (for example, Japanese Patent Publication 2011-153209 publications Described carbodiimide).These can also find to imitate with above-mentioned HMW carbodiimide identical even if for low molecule amount Fruit.This is due to that ring-opening reaction, a side and the pet reaction, open loop occur for the terminal carboxylic of polyester and the carbodiimide of ring-type The opposing party and other polyester react and molecular weight, therefore, suppress the generation of isocyanates system gas.

In these have the material of cyclic structure, in the present invention, end-capping reagent is preferably to have carbodiimide, and is had The carbodiimide compound for the cyclic structure that its first nitrogen and the second nitrogen are bonded by being bonded base.Moreover, end-capping reagent is more excellent Elect the carbodiimide (being also called aromatic cyclic carbodiimide) for including cyclic structure, the carbodiimide tool of the cyclic structure as There are the carbodiimide that at least one is adjacent with aromatic rings, and the first nitrogen and the second nitrogen of the carbodiimide adjacent with aromatic rings It is bonded by being bonded base.

Aromatic cyclic carbodiimide can have multiple cyclic structures.

If aromatic cyclic carbodiimide can be preferably by intramolecular without the carbodiimide of more than 2 The aromatic series carbon diimine for the ring structure that first nitrogen and the second nitrogen are bonded by being bonded base, i.e., monocyclic aromatic series carbon diimine.

Cyclic structure has 1 carbodiimide (- N=C=N-), and its first nitrogen and the second nitrogen are by being bonded base key Close.Only there is 1 carbodiimide in 1 cyclic structure, such as loop coil etc., when having multiple cyclic structures in the molecule, If having 1 carbodiimide in each cyclic structure being bonded with spiro-atom, there can be multiple carbon two as compound Imido grpup is self-evident.Atomicity in cyclic structure is preferably 8~50, more preferably 10~30, more preferably 10~ 20, especially preferably 10~15.

Here, the atomicity in cyclic structure means to directly constitute the quantity of the atom of cyclic structure, for example, if 8 Yuan of rings are then 8, are then 50 if 50 yuan of rings.If this, which is due to atomicity in cyclic structure, is less than 8, cyclic carbodimide The stability of compound declines, and takes care of sometimes, using can become difficult.And according to the viewpoint of reactivity, for the upper of first number of rings Limit value is not particularly limited, but atomicity be less than 50 Cyclic carbodiimide compound synthesis difficulty it is smaller, can will be into Originally it is suppressed to relatively low.According to related viewpoint, the atomicity in cyclic structure is preferably 10~30, and more preferably 10~20, especially It is preferred that 10~15 scope.

As the concrete example of the carbodiimide system end-capping reagent with cyclic structure, following compound can be enumerated.But this hair It is bright not to be limited because of example in detail below.

[chemical formula 1]

(epoxy end-capping reagent)

As the preference of epoxide, epihydric alcohol ester compound and glycidyl ether compound etc. can be enumerated.

As the concrete example of epihydric alcohol ester compound, glycidyl benzoate, p t butylbenzoic acid contracting can be enumerated Water glyceride, to toluene acid glycidyl ester, cyclohexane-carboxylic acid ethylene oxidic ester, n-nonanoic acid ethylene oxidic ester, stearic acid shrink it is sweet Grease, bay acid glycidyl ester, palm acid glycidyl ester, behenyl acid glycidyl ester, glycidyl neodecanoate, oleic acid Ethylene oxidic ester, linoleic acid ethylene oxidic ester, linolenic acid ethylene oxidic ester, Dill acetylenic acids ethylene oxidic ester, stearic acid shrink sweet Grease, terephthalic acid diglycidyl ester, Diglycidyl M-phthalate, o-phthalic acid diglycidyl ester, naphthalene Dicarboxylic acids 2-glycidyl ester, methylterephthalic acid's 2-glycidyl ester, hexahydrophthalic acid 2-glycidyl ester, tetrahydrochysene O-phthalic acid diglycidyl ester, cyclohexane dicarboxylic acid 2-glycidyl ester, adipic acid 2-glycidyl ester, butanedioic acid two contract Water glyceride, Diglycidyl Sebacate, the ketone acid 2-glycidyl ester of dodecane two, octadecane dicarboxylic acids 2-glycidyl Ester, trimellitic acid three-glycidyl ester and pyromellitic acid tetra glycidyl ester etc., and can use these in a kind or 2 kinds with On.

Also, as the concrete example of glycidyl ether compound, phenyl glycidyl ether, adjacent phenyl glycidyl can be enumerated Ether, Isosorbide-5-Nitrae-bis- (beta, gammas-glycidoxy) butane, 1,6- double (beta, gamma-glycidoxy) hexane, Isosorbide-5-Nitrae-bis- (beta, gamma-epoxies third Epoxide) benzene, 1- (beta, gamma-glycidoxy) -2- Ethoxyethanes, 1- (beta, gamma-glycidoxy) -2- benzyloxies ethane, 2, 2- is double-[p- (beta, gamma-glycidoxy) phenyl] propane and 2,2- it is double-(4- hydroxyphenyls) propane or 2,2- it is double-(4- hydroxyphenyls) Bisglycidyl base polyethers that methane etc. is obtained using the reaction of bis-phenol and epichlorohydrin etc., they can be used one kind or two or more.

(oxazolines system end-capping reagent)

Zuo Wei oxazoline compounds, You Xuan bisoxazoline compounds, it can specifically exemplify 2,2 '-bis- (2- oxazoles Quinoline), 2,2 '-bis- (4- methyl -2- oxazolines), 2,2 '-bis- (4,4- dimethyl -2- oxazolines), 2,2 '-bis- (4- ethyls -2- Oxazoline), 2,2 '-bis- (4,4 '-diethyl -2- oxazolines), 2,2 '-bis- (4- propyl group -2- oxazolines), 2,2 '-bis- (4- fourths Base -2- oxazolines), 2,2 '-bis- (4- hexyl -2- oxazolines), 2,2 '-bis- (4- phenyl -2- oxazolines), 2,2 '-bis- (4- hexamethylenes Base -2- oxazolines), 2,2 '-bis- (4- benzyl -2- oxazolines), 2,2 '-TOPOT 2,2′ p phenylenebis (2- oxazolines), 2,2 '-metaphenylene Double (2- oxazolines), 2,2 '-adjacent phenylene double (2- oxazolines), 2,2 '-TOPOT 2,2′ p phenylenebis (4- methyl -2- oxazolines), 2,2 ' - TOPOT 2,2′ p phenylenebis (4,4- dimethyl -2- oxazolines), 2,2 '-metaphenylene double (4- methyl -2- oxazolines), 2,2 '-sub- benzene Base double (4,4- dimethyl -2- oxazolines), 2,2 '-ethylenebis (2- oxazolines), 2,2 '-tetramethylene double (2- oxazolines), 2,2 '-hexamethylene bis (2- oxazolines), 2,2 '-eight di-2-ethylhexylphosphine oxides (2- oxazolines), 2, double (the 2- oxazoles of 2 '-decamethylene Quinoline), 2,2 '-ethylenebis (4- methyl -2- oxazolines), 2,2 '-tetramethylene double (4,4- dimethyl -2- oxazolines), 2,2 ' - 9,9 '-biphenoxyl ethane double (2- oxazolines), 2,2 '-cyclohexylidene is double (2- oxazolines) and 2, double (the 2- Evil of 2 '-diphenylene Oxazoline) etc..Among those, from the reactivity with polyester, most preferably with 2,2 '-bis- (2- oxazolines).On moreover, Can realize the purpose of the present invention as long as stating and enumerating bisoxazoline compounds, then can be used alone a kind, also can by 2 kinds with On be used in combination.

This end-capping reagent needs to be directed into polyester film.Do not react directly even, can not obtain above-mentioned with polyester molecule Effect.This is due to that coating layer is added on PET, and polyester will not also react with end-capping reagent.

<Other layers>

The stacked film of the present invention can also be laminated with other layers in addition to the 1st layer, the 2nd layer., can be with as other layers Enumerate relatively low layer of the higher layer of whiteness (space or the more layer of particle), whiteness (space or the less layer of particle) etc.. As other layers, for example, can referenced patent disclose 2013-65846 publications 0065~0066 section of grade record, in these Appearance is incorporated into present specification.

<The physical property of stacked film>

In the stacked film of the present invention, the overall Chinese white concentration of stacked film is more than 0 mass % and less than 2 mass %, excellent 0.5 mass % is elected as less than 2 mass %, more preferably 1.5 mass % are less than 2 mass %.By by film Overall Chinese white concentration is set to be more than 0 mass %, it is possible to increase visible ray is disguised, by being set to be less than 2 mass %, energy Enough improve hydrolytic resistance.

The overall Chinese white concentration of film is by the quality of shared Chinese white in the overall quality of stacked film Ratio parameter expressed as a percentage, specifically, it can determine by the following method.That is, in crucible, using stacked film as Measure sample takes 3g, and with 900 DEG C of heating for carrying out 120 minutes in electric oven.Earthenware is taken out after being cooled down afterwards in electric oven Crucible, and determine the quality of the ash content remained in crucible.The ash content is Chinese white powder, by the quality of ash content divided by measure sample Quality and be multiplied by 100 value as Chinese white concentration.

Amount (the end carboxy concentration that hydrolytic resistance passes through terminal carboxyl group；AV) improved.Therefore, stacked film is overall End carboxy concentration is 6~30 equivalents/ton, preferably 10~25 equivalents/ton, more preferably 10~20 equivalents/ton.

If end carboxy concentration is less than 6 equivalents/ton, the carboxyl (COOH yls) on surface becomes that very few (polarity became It is low), the cementability adhesiveness with different materials can decline sometimes.Also, if end carboxy concentration gathers more than 30 equivalents/ton The H of the COOH bases of ester molecule end⁺Promote to hydrolyze as catalyst, sometimes result in hydrolytic resistance decline.

In addition, end carboxy concentration is after polyester 0.1g is dissolved in into phenmethylol 5ml, the mixed of 5ml chloroforms with the addition of Close in solution and instill phenolic red indicator, it is titrated with benchmark liquid (0.01N KOH- phenmethylols mixed solution), and by this The value that infusion volume calculates.

The overall thickness of stacked film is preferably 100~400 μm, more preferably 100~300 μm, more preferably 100~ 250 μm, especially preferably 110~250 μm.

Also, the 1st layer of thickness is relative to the ratio between overall thickness of stacked film (overall thickness of the 1st layer of thickness/stacked film Degree) it is preferably 0.01~0.30, more preferably 0.02~0.25.

The present invention stacked film can be used in various uses, can be used in solar module film (such as Diaphragm of solar cell etc.), building materials film and outdoor advertising film etc..

<The manufacture method of stacked film>

The manufacture method of stacked film of the present invention has no particular limits, but from the cementability of interlayer and the viewpoint of productivity ratio From the point of view of, preferably manufactured by coetrusion.When for the double-decker of layers 1 and 2 when, prepare 2 extruders, one It is put into individual extruder and forms the 1st layer of composition, is put into another extruder and forms the 2nd layer of composition, and will be from The molten mass (melt) of each extruder extrusion makes its interflow using bilayer charging block assembly, and remain its laminated arrangement and Extruded from mould, so as to obtain non-stretched stacked film (coextrusion process).Biaxial stretch-formed (stretching work can be carried out to stacked film Sequence) come obtain the present invention stacked film.

Polyester for the 1st layer and the 2nd layer carries out solid phase preferably after polycondensation.Solid phase as described above, it is preferred to Mode it is same.

In process is coextruded, it will be kneaded via the polyester melt after solid phase, and by for forming the 1st layer of composition 1st layer of composition and the composition of the 2nd layer of the composition for forming the 2nd layer are melted respectively with 2 extruders, and By molten mass (melt) after collaborating during bilayer feeds block assembly and being set to laminated arrangement, extruded from mould, and forming the 2nd layer Composition at least one face on stacking form the 1st layer of composition, be consequently formed stacked film.

For example, the polyester polymerizeing via above-mentioned solid phase is dried, after residual moisture is set into below 100ppm, utilize Extruder is melted.Melting temperature be preferably more than 250 DEG C and less than 320 DEG C, more preferably more than 260 DEG C and 310 DEG C with Under, more preferably more than 270 DEG C and less than 300 DEG C.

From the point of view of further the end COOH this point caused by thermal decomposition is suppressed, more preferably put to carrying out nitrogen in extruder Change.

The molten mass (melt) melted in an extruder after gear pump, filter etc. from mould by extruding.Now, will use In the composition for the 2nd layer of composition for forming the 2nd layer and for forming the 1st layer at least one side side for the composition for forming the 2nd layer The 1st layer of composition composition using feeding after block assembly collaborates and be set to laminated arrangement, extruded from mould and stacked film be made.

Forming the 1st layer of composition can be laminated on a face for forming the 2nd layer of composition, can also be in two faces Upper stacking.

Utilize chilled roll (chilled roll, chill roll) to be cooled down from the melt of each extrusion die coextrusion, Solidification.Now, the temperature of chilled roll is preferably more than 10 DEG C and less than 80 DEG C, more preferably more than 15 DEG C and less than 70 DEG C, More preferably more than 20 DEG C and less than 60 DEG C.In addition, from the adhesiveness improved between melt and chilled roll, and improve cold But from the viewpoint of efficiency, preferably it is previously applied electrostatic before chilled roll and melt contacts.Moreover, further preferably rolled from chill The opposite of roller blows cold wind and contacted with chill roll to promote to cool down.Thus, even if (specifically, the thickness after stretching is for thick film More than 250 μm, the further film for more than 300 μm), also can effectively be cooled down.

In addition, when cooling down insufficient, spherocrystal is also easy to produce, this causes stretching uneven sometimes, and produces uneven thickness.

In stretching process, carry out by be coextruded process make non-stretched stacked film vertical stretching and horizontal stretching, And (the Tg1 more than (Tg1+10) DEG C and below (Tg1+35) DEG C by film surface temperature control during vertical stretching and during horizontal stretching Represent the 1st layer of glass transition temperature).If film surface temperature during vertical stretching and during horizontal stretching for (Tg1+10) DEG C with On, then due to stress during stretching can be reduced, therefore can be stretched in the case where assigning the stretching ratio needed for hydrolytic resistance, If below (Tg1+35) DEG C, then the orientation needed for the improvement of hydrolytic resistance can be assigned.When biaxial stretch-formed (during vertical stretching and horizontal stroke During stretching) film surface temperature be more preferably more than (Tg1+12) DEG C and (Tg1+30) DEG C below.

For example, non-stretched stacked film is imported into the roller group for the temperature for being heated to more than 70 DEG C and less than 140 DEG C, and edge Length direction (longitudinal direction, i.e. the direction of advance of film) is stretched with the extensibility of more than 3 times and less than 5 times, and with 20 DEG C with Upper and 50 DEG C of temperature below roller groups are cooled down.Then, drawn while the both ends of film with clip hold while importing Width machine, and be heated to more than 80 DEG C and in the atmosphere of less than 150 DEG C of temperature, it is (wide along the direction at a right angle with length direction Degree direction) stretched with the extensibility of more than 3 times and less than 5 times.

Length direction and width are preferably set to more than 3 times and less than 5 times by extensibility.Also, its area times Rate (vertical stretching ratio × horizontal stretching ratio) is preferably more than 9 times and less than 15 times.If area multiplying power is more than 9 times, can obtain The reflectivity of the biaxial stretch-formed stacked film obtained and disguised and film strength are good, and if area multiplying power is less than 15 times, Breakage during stretching can be avoided.

As carrying out biaxial stretch-formed method, the stretching except carrying out length direction and width respectively as described above Gradually beyond biaxial stretching method, biaxial stretching method while also having the stretching for carrying out length direction and width simultaneously, Can be any of the two.

In order to complete the crystalline orientation of obtained biaxially oriented film and assign flatness and dimensional stability, continue The heat fixation processing of biaxially oriented film is carried out in stenter, equably gradually can be cooled to room temperature after cooling.Generally, it is hot The thermal contraction of the more low then film of fixing process temperature (Ts) is bigger, therefore in order to assign high thermal dimensional stability, is preferably heat-treated Temperature is higher.However, oriented crystalline declines if heat treatment temperature is too high, the hydrolytic resistance for the film that its result is formed has When it is poor.

In the present invention, when carrying out the heat fixation processing of biaxially oriented film, it is set to by the 2nd layer of crystalline melting peak In the case of Tm2 (DEG C), by film surface temperature control during heat fixation more than (Tm2-40) DEG C and less than Tm2 DEG C.It is if hot Film surface temperature when fixed is more than (Tm2-40) DEG C, then the removal effect of the overstrain based on heat fixation is abundant, heat The level turned into permissible range is shunk, if less than Tm2 DEG C, then can be prevented water-fast as caused by relaxing the 2nd layer of orientation The deterioration of solution property.

In addition, the stacked film of the present invention can act as forming the backboard of solar module, gas sometimes during module is used Atmosphere temperature can rise to 100 DEG C or so.Therefore, more than film surface temperature during heat fixation more preferably (Tm2-30) DEG C And below (Tm2-10) DEG C.

And can as needed in the width direction or length direction implement 1~12% relaxation processes.For thermosetting Fixed polyester film, below Tg is generally cooled to, and cuts away the clip grip portion and wound into rolls at polyester film both ends.This When, preferably below final heat fixation treatment temperature and within the temperature range of more than Tg in the width direction and/or length direction enters The relaxation processes of row 1~12%.

Also, from the viewpoint of dimensional stability, cooling preferably from final heat-fixing temperature untill room temperature with per second 1 More than DEG C and less than 100 DEG C of cooling velocity is gradually cooled down.Especially, from Tg+50 DEG C untill Tg, preferably with 1 DEG C per second Above and less than 100 DEG C of cooling velocity is gradually cooled down.Cooled down and the method for relaxation processes is not particularly limited, can be with Carried out using known method, but from improve stacked film dimensional stability from the viewpoint of, particularly preferably while Cooling is carried out in multiple temperature provinces successively while carrying out these processing.

Also, when manufacturing above-mentioned stacked film, for the purpose of improving and be laminated film strength, can carry out multistage vertical stretching, The stretching used known to stretching, again vertically and horizontally stretching, transverse and longitudinal stretching etc. in oriented film is indulged again.Vertical stretching and horizontal drawing The order stretched can be opposite.

The detailed content of the manufacture method of stacked film can be see, for example Japanese Patent Publication 2011-211087 publications The record of 0098~0110 section of grade, these contents are incorporated into present specification.

<Solar module backboard>

The backboard used for solar batteries of the present invention includes the stacked film of the present invention.The backboard used for solar batteries of the present invention leads to Cross the stacked film that the present invention is set and form, and relative to adherend, can be as needed at least provided with the easy of 1 layer of easy-adhesion Cementability layer, UV-absorbing layer, there is the functional layer such as white layer of light reflective and form.Due to possessing the layer of the present invention Folded film, therefore stable endurance quality is shown in long-term use.

The present invention backboard used for solar batteries for example can after uniaxial tension and/or it is biaxial stretch-formed after stacked film on It is coated with following function layer.Being coated with middle energy uses rolling method, blade coating (knife edge) method, gravure coating process, curtain to apply Coating technique known to cloth method etc..

Also, can implement before carrying out these and being coated with surface treatment (flame treatment, sided corona treatment, at plasma Reason, UV treatment etc.).Also, it is preferred that it is bonded using adhesive.

(easy-adhesion layer)

Using the present invention stacked film to form solar module when, preferably solar cell device with encapsulation The side that the encapsulating material of the battery side substrate of agent encapsulation is opposite has easy-adhesion layer.By relative to (outstanding comprising encapsulant It is ethylene vinyl acetate copolymer) adherend (for example, the battery side substrate that solar cell device is encapsulated with encapsulating material Encapsulant surface) set show cementability easy-adhesion layer, will can be bonded securely between backboard and encapsulant.Tool Body, easy-adhesion layer is 10N/cm especially with the bonding force of the EVA (ethylene vinyl acetate copolymer) as encapsulating material More than, preferably more than 20N/cm.

Moreover, easy-adhesion layer can not cause the stripping of backboard in the use of solar module, it is expected for this easy Cementability layer has higher humidity resistance.

(adhesive)

Easy-adhesion layer can include at least one kind of of adhesive.As adhesive, for example, can use polyester, polyurethane, Acrylic resin, polyolefin etc..Wherein, from the viewpoint of durability, preferred acrylic resins, polyolefin.Also, as third Olefin(e) acid resin, it is also preferred that the compound resin of acrylic acid and silica gel.As preferable adhesive, example below can be enumerated.

As the example of said polyolefins, CHEMIPEARL S-120 can be enumerated, CHEMIPEARL S-75N (is Mitsui Chemicals, Inc. system).As the example of aforesaid propylene acid resin, can enumerate JURYMER ET-410, JURYMER SEK-301 (being Nippon Pure Chemical Co., Ltd.s system).Also, as aforesaid propylene acid and silicon The example of the compound resin of glue, CERANATE WSA1060 can be enumerated, CERANATE WSA1070 (is DIC Corporation systems) and H7620, H7630, H7650 (being ASAHI KASEICHEMICALS CORPORATION systems).

The amount of above-mentioned adhesive is preferably 0.05~5g/m²Scope, particularly preferred 0.08~3g/m²Scope.Adhesive Amount is by for 0.05g/m²Better bonding force can be obtained above, by for 5g/m²Better face can be obtained below Shape.

(particulate)

Easy-adhesion layer can contain fine-grained at least one kind of.Contain in easy-adhesion layer preferably with respect to the overall quality of layer There is particulates more than 5 mass %.

As particulate, the inorganic micro- of silica, calcium carbonate, magnesia, magnesium carbonate, tin oxide etc. can be suitably enumerated Grain.From the point of view of the less this point of decline of cementability wherein when exposed to damp and hot atmosphere, particularly preferred tin oxide, silica Particulate.

The particle diameter of particulate is preferably 10~700nm or so, more preferably 20~300nm or so.By using particle diameter upper The particulate of scope is stated, good easy-adhesion can be obtained.For particulate shape without especially limiting, can use it is spherical, The particulate of unsetting, aciculiform etc..

It is preferably 5~400 relative to the adhesive in easy-adhesion layer as addition of the particulate in easy-adhesion layer Quality %, more preferably 50~300 mass %.If the addition of particulate is more than 5 mass %, when in damp and hot atmosphere It is excellent in adhesion, if below 400 mass %, then the planar of easy-adhesion layer is better.

(crosslinking agent)

Easy-adhesion layer can contain at least one kind of of crosslinking agent.

As the example of crosslinking agent, epoxy, isocyanates system, melamine series, carbodiimide Xi, oxazoles can be enumerated The crosslinking agent of quinoline system etc..From ensure it is damp and hot through when after cementability from the viewpoint of, Qi You Xuan oxazolines systems of You among those Crosslinking agent.

As the concrete example of Shang Shu oxazolines system crosslinking agent, 2- vinyl -2- oxazolines, 2- vinyl -4- can be enumerated Methyl -2- oxazolines, 2- vinyl -5- methyl -2- oxazolines, 2- isopropenyl -2- oxazolines, 2- isopropenyl -4- methyl - 2- oxazolines, 2- isopropenyl -5- ethyl-2-oxazolines, 2,2 '-bis--(2- oxazolines), 2,2 '-methylene-bis--(2- oxazoles Quinoline), 2,2 '-vinyl-bis--(2- oxazolines), 2,2 '-trimethylene-bis--(2- oxazolines), 2,2 '-tetramethylene-bis-- (2- oxazolines), 2,2 '-hexa-methylene-bis--(2- oxazolines), 2,2 '-eight methylene-bis--(2- oxazolines), 2,2 '-ethene Base-bis--(4,4 '-dimethyl -2- oxazoline), 2,2 '-to phenylene-bis--(2- oxazolines), 2,2 '-metaphenylene-bis--(2- Oxazoline), 2,2 '-metaphenylene-bis--(4,4 '-dimethyl -2- oxazoline), double-(2- oxazolinyls hexamethylene) thioether, it is double - (2- oxazolinyls norcamphane) thioether etc..It can also enough it is preferably by these compound (co) polymerization bodies.

Also, as the compound of Ju You oxazolinyls, it can also utilize Epocros K2010E, Epocros K2020E, Epocros K2030E, Epocros WS500, Epocros WS700 (be NIPPON SHOKUBAI CO., LTD. make) etc..

Preferred addition of the crosslinking agent in easy-adhesion layer is preferably 5~50 matter relative to the adhesive of easy-adhesion layer Measure %, more preferably 20~40 mass %.Good crosslinking effect can be obtained for more than 5 mass % by making the addition of crosslinking agent Fruit, and be not easy to cause the intensity in reflecting layer to decline and poor attachment, by can be by the working life of coating fluid for below 50 mass % It is more permanent to be kept as.

(additive)

Polystyrene, polymethyl methacrylate, titanium dioxide can further be added as needed in easy-adhesion layer Interfacial agent etc. known to delustering agent, anion system or nonionic system etc. known to silicon etc..

(forming method of easy-adhesion layer)

As the forming method of easy-adhesion layer, have and fit to the polymer flake with easy-adhesion on polyester film Method or method based on coating, the method based on coating is easy and can be formed as the higher film of uniformity, from this From the point of view of point preferably.As coating method, such as method known to intaglio plate coating or rod painting etc. can be utilized.As for coating The solvent of coating fluid, can be water, or such as toluene or the organic solvent of methyl ethyl ketone.Solvent can be used alone a kind, also may be used So that two or more to be used in mixed way.

Also, during by being coated with to form easy-adhesion layer, as described in the manufacture method in the present invention, preferably It is simultaneous in dry section after heat treatment to be coated layer drying and heat treatment.In addition, dyed layer described later is formed by being coated with It is or also identical during other functional layers.

(physical property)

The thickness of easy-adhesion layer is not particularly limited, it is often preferred that 0.05~8 μm of scope, more preferably 0.1~5 μm Scope.By the way that the thickness of easy-adhesion layer is set into more than 0.05 μm, required easy-adhesion can be readily available, by setting For less than 8 μm, planar can be preferably maintained.

On easy-adhesion layer, from not influenceing to colour when being configured with dyed layer (especially reflecting layer) between polyester film From the viewpoint of the effect of layer, preferably there is the transparency.

<Solar module>

The solar module of the present invention is characterised by the stacked film comprising the present invention or the backboard of the present invention.

The solar module of the present invention is configured to the transparent substrate in incident sunshine and the already described present invention Stacked film (backboard used for solar batteries) between configuration the luminous energy of sunshine is converted into the solar cell device of electric energy.Base It can be configured to carry out such as with the resin (so-called encapsulating material) ethylene vinyl acetate copolymer between plate and stacked film Encapsulation.

On the part beyond solar module, solar battery cell, backboard, such as it is recorded in detail " too Photovoltaic power generation system constituent material " (supervise, Kogyo Chosakai Publishing Co., Ltd.s, 2008 by China fir this honor one Distribution).

The substrate of the transparency can fit as long as there is the transmitance of permeable sunshine from the base material of transmitted light Locality selection.From the viewpoint of generating efficiency, the transmissivity of light is more high more preferred, as this substrate, such as can be appropriate Ground uses transparent resins such as glass substrate, acrylic resin etc..

As solar cell device, can be applicable the silicon systems such as monocrystalline silicon, polysilicon, non-crystalline silicon, copper-indium-gallium-selenium, copper- The various known solar cell devices of the iii-vs or II-VI group group compound semiconductor system etc. such as indium-selenium, cadmium-tellurium, gallium-arsenic.

Embodiment

Following examples and comparative example are enumerated the feature of the present invention to be described in further detail.Following examples Shown in material, usage amount, ratio, process content, processing sequence etc. then can be appropriate without departing from spirit of the invention Changed on ground.Therefore, the scope of the present invention is should not be construed as to be limited by concrete example as shown below.

Embodiment 1：The making of stacked film

<The synthesis of polyester>

-ester-

In the first esterification groove, by 1.8 tons of high purity terephthalic acid 4.7 tons (4700kg) and ethylene glycol (1800kg) carries out the mixing of 90 minutes to form mud, and is continuously supplied in the first esterification groove with 3800kg/h flow In.Further continuously supply citric acid be coordinated in Ti metals lemon acid sequestering agent titanium complex (VERTEC AC-420, Johnson Matthey Japan G.K. systems) ethylene glycol solution, and 250 DEG C of temperature, the bar being stirred in reactive tank Under part, reacted with the mean residence time of about 4.3 hours.Now, turned into according to Ti additions in terms of Ti element scaled values 9ppm mode continuously adds lemon acid sequestering agent titanium complex.Now, the acid number of the oligomer obtained is 600 equivalents/ton.

The reactant is transferred to the second esterification groove, is being stirred, in reactive tank under conditions of 250 DEG C of temperature, Reacted with the mean residence time of 1.2 hours, so as to obtain the oligomer that acid number is 200 equivalents/ton.Second esterification The inside of groove is separated into 3 areas, is turned into from the 2nd area by the ethylene glycol solution of magnesium acetate according to Mg additions in terms of element scaled value 67ppm mode is continuously supplied, then from the 3rd area by the ethylene glycol solution of trimethyl phosphate according to P additions with member Plain scaled value meter is carried out continuously supply as 65ppm mode.

- polycondensation reaction-

Esterification reaction product by above-mentioned acquisition is continuously fed in the first polycondensation reaction groove, be stirred, Pressure 2.67 × 10 in 270 DEG C of reaction temperature, reactive tank^-3Under conditions of MPa (20torr), with the Mean Residence of about 1.8 hours Time carries out polycondensation.

And then be transferred in the second polycondensation reaction groove, and in the reactive tank to be stirred, temperature 276 in reactive tank DEG C, pressure 6.67 × 10 in reactive tank^-4MPa (5torr), the condition of about 1.2 hours holdup times are reacted (polycondensation).

Then, it is further transferred in the 3rd polycondensation reaction groove, in the reactive tank, with 278 DEG C of temperature in reactive tank, instead Answer pressure 2.0 × 10 in groove^-4MPa (1.5torr), the condition of 1.5 hours holdup times are reacted (polycondensation), anti-so as to obtain Answer product (PET；PET is simply denoted as below).

For the PET (reaction product) obtained, high de-agglomeration energy type high-frequency inductive coupling plasma weight point is utilized Analyse (HR-ICP-MS；SII Nano Technology company system AttoM) it is measured.As a result, Ti=9ppm, Mg= 67ppm, P=58ppm.P is slightly reduced relative to initial addition, and this deducibility is is because of institute of volatilizing in the course of the polymerization process Cause.

- solid phase process-

(diameter 3mm, length 7mm) will be granulated by the PET of above-mentioned polymerization, and for resulting resin particle (Gu Have viscosity IV=0.60dl/g, end carboxy concentration=25 equivalents/ton) solid phase is implemented as follows.

, can be by the way that polyester be melted in o-chlorphenol, and according to 25 in addition, the intrinsic viscosity (IV) on polyester The solution viscosity determined at DEG C calculates intrinsic viscosity by following formula.

η sp/C=[η]+K [η]²·C

Here, η sp=(solution viscosity/solvent viscosity) -1, C is dissolving polymer weight (this measure per 100ml solvents In be set to 1g/100ml), K is Huggins constant (being set to 0.343), and solution viscosity, solvent viscosity can utilize oersted Wa Er Moral viscosimeter determines.

For the polyester being polymerize by already described esterification in solid phase, existed using -30 DEG C of nitrogen of dew-point temperature Heated 7 minutes in 140 DEG C, and it is Pre-crystallizing to carry out for the purpose of set during preventing solid phase.

Dried 4 hours in 165 DEG C followed by the heated nitrogen of -30 DEG C of dew-point temperature, make moisture rate in resin into For below 50ppm.

Then, after dry polyester resin being preheated into 205 DEG C, followed by carrying out 25 hours nitrogen in 207 DEG C Ring carries out solid phase.As nitrogen circulation condition, by gas ratio (relative to the nitrogen amount of the circulation of the amount of resin of discharge) It is set to 1.5m³/ kg, superficial linear velocity in a column are set to the 0.08m/ seconds, glycol concentration is set to 240ppm, water concentration is set to 12ppm, pass through second Mole intrinsic standoff ratio of glycol and water (mole partial pressure of mole partial pressure/water of ethylene glycol) carries out solid polycondensation using 20 nitrogen Close.In order to be set to above-mentioned mixed gas composition, the ethylene glycol of moisture content 100ppm high-purity is used in ethylene glycol washer, And the temperature of washer is set to 35 DEG C.Pressure in washer is set to 0.1MPa~0.11MPa scope.

Then the resin discharged from reaction process (500kg/h) is cooled to 60 DEG C.The intrinsic viscosity of resulting resin Spend IV=0.78dl/g, end carboxy concentration=9 equivalents/ton.

<The making of master batch>

It is kneaded in PET particles in a manner of titanium oxide turns into 40~60 mass % to make master batch.

<Extrusion film>

For the 1st layer, above-mentioned PET and above-mentioned master batch are mixed in a manner of titanium oxide concentration turns into 12 mass %, And be dried to below moisture content 100ppm, it is supplied in extruder 1 and with 285 DEG C of progress melting extrusions.As extruder 1, use the biaxial extruder of the equidirectional Xuan Zhuan Nogami mould assemblys of the dual blow vent formula for possessing 2 blow vents.

For the 2nd layer, above-mentioned PET and the stacked film to being obtained width end are subjected to trimming crushing and made The recovery fragment of work is mixed in a manner of titanium oxide concentration turns into 0.2 mass %, and is dried to moisture content 100ppm After below, extruder 2 is supplied in and with 285 DEG C of progress melting extrusions.As extruder 2, have using in the same manner as extruder 1 The biaxial extruder of the equidirectional Xuan Zhuan Nogami mould assemblys of dual blow vent formula of 2 blow vents.

The molten mass (melt) from each outlet of extruder extrusion is set to pass through gear pump, metal fiber filter (20 μm of aperture) Afterwards, make its interflow using bilayer charging block assembly, and remain its laminated arrangement and be expressed into from mould on chill roll.For The melt extruded applies method using electrostatic and is adhered on chill roll.Chill roll utilizes hollow casting roller, and makes wherein Water as thermophore is by carrying out temperature adjustment.

<Stretching is batched>

For being expressed into the non-stretched film on chill roll and solidified using the above method, implement by the following method gradually It is biaxial stretch-formed, so as to obtain the film of 250 μ m thicks.In addition, stretching carries out vertical stretching with 95 DEG C, carries out horizontal stretching with 140 DEG C, And carried out with the order of vertical stretching, horizontal stretching.Afterwards, after carrying out 12 seconds heat fixations with 210 DEG C, transversely relaxed with 205 DEG C 3%.After stretching, 10cm is respectively trimmed at both ends, and after implementing thickness processing to both ends, rolled up in diameter 30cm resin-made core Around 3000m.In addition, width is 1.5m.Also, the 1st layer of thickness is 10 μm, and the 2nd layer of thickness is 240 μm.

The result calculated according to the product of the 1st layer of thickness, the 1st layer of density and Chinese white concentration, the 1st layer white Color density of pigment is 1.8 × 10^-4g/cm²。

- vertical stretching-

Make non-stretched film by between 2 pairs of different rolls of peripheral speed, and entered with following conditions along longitudinal direction (conveying direction) Row stretching.

Preheating temperature：95℃

Draft temperature：95℃

Stretching ratio：3.5 again

Draw speed：3000%/second

- it is horizontal stretching-

Above-mentioned film for indulging stretching, horizontal stretching is carried out by following conditions using stenter.

Preheating temperature：110℃

Draft temperature：120℃

Stretching ratio：3.9 again

Draw speed：70%/second

<Evaluation of measuring>

Following measure, evaluation are carried out for the PET before and after the solid phase by above-mentioned acquisition.

- end carboxy concentration-

After polyester 0.1g is dissolved in into phenmethylol 5ml, phenol red instruction is instilled in the mixed solution that with the addition of 5ml chloroforms Agent, it is titrated with benchmark liquid (0.01N KOH- phenmethylols mixed solution).The dense of terminal carboxyl group is calculated by infusion volume Spend [equivalent/ton].

- Chinese white concentration-

The overall Chinese white concentration of film is by the ratio of the quality of Chinese white shared in the overall quality of stacked film Example parameter expressed as a percentage, can specifically be determined by the following method.That is, in crucible, using stacked film as measure Sample takes 3g, and with 900 DEG C of heating for carrying out 120 minutes in electric oven.Crucible is taken out after being cooled down afterwards in electric oven, and Determine the quality of the ash content remained in crucible.The ash content is Chinese white powder, by the quality of ash content divided by the matter of measure sample Measure and be multiplied by the 100 value Chinese white concentration overall as stacked film.

1st layer of Chinese white concentration in said determination method by being used as measure sample in stacked film using 3g's 1st layer is similarly measured.

2nd layer of Chinese white concentration in said determination method by being used as measure sample in stacked film using 3g's 2nd layer is similarly measured.

Embodiment 2~11, comparative example 1~11：The making of stacked film

By the overall Chinese white concentration of the 1st layer in embodiment 1 and the 2nd layer of Chinese white density, thickness, film and End carboxy concentration etc. is changed to such as the record in following tables, similarly produce other embodiment and comparative example in addition Stacked film.

- hydrolytic resistance-

For the film obtained by film~stretch process, provided with 120 DEG C under 100% wet heat condition Time-triggered protocol, extension at break degree measure is carried out by JIS-K7127 methods afterwards, and commented according to following metewands Valency.A and B is the benchmark that can be allowed in actual use.

A：Extension at break degree reduces time untill the 50% of untreated membrane more than 90 hours and for less than 100 hours

B：Extension at break degree reduces time untill the 50% of untreated membrane more than 80 hours and for less than 90 hours

C：Extension at break degree reduces time untill the 50% of untreated membrane more than 70 hours and for less than 80 hours

D：The time that extension at break degree is reduced untill the 50% of untreated membrane is less than 70 hours

- visible ray disguise-

By the optical concentration (O.D.) in Macbeth optical concentrations meter measure visible region (380-700nm), and according to Following metewands are evaluated.A, B and C is the benchmark that can be allowed in actual use.

A：Optical concentration is more than 0.6 [O.D.]

B：Optical concentration more than 0.5 [O.D.] and for 0.6 [O.D.] below

C：Optical concentration more than 0.4 [O.D.] and for 0.5 [O.D.] below

D：Optical concentration be 0.4 [O.D.] below

[table 1]

From above-mentioned table, in the 1st layer, the 2nd layer and the overall embodiments 1~11 for all meeting regulation important documents of stacked film, Hydrolytic resistance and visible ray disguise are excellent.On the other hand, it is known that in the 1st layer, the 2nd layer and stacked film entirety any one not In the comparative example 1~11 for meeting regulation important document, both hydrolytic resistance and visible ray disguise can not be met.

Industrial applicability

The stacked film of the present invention can maintain intensity for a long time out of doors because hydrolytic resistance is excellent, and visible ray It is disguised also excellent, therefore design is also excellent.By using the stacked film of the present invention, solar module use can be obtained Backboard and solar module.Moreover, the stacked film of the present invention can be used in building materials with film, outdoor advertising with film etc., And utilizability industrially is higher.

Symbol description

The 1st layer of the 2nd layer of 10-, 12-.

Claims (7)

1. a kind of stacked film, it at least has the 1st layer and the 2nd layer containing polyester containing polyester and Chinese white, wherein,

Described 1st layer is in contact with described 2nd layer of at least one face,

Described 1st layer of Chinese white density is 4.3 × 10^-4~5.4 × 10^-4g/cm²,

Described 1st layer of thickness is 30~50 μm,

Described 2nd layer of thickness is 100~300 μm,

The overall Chinese white concentration of the stacked film is 1.58 mass % less than 2 mass %,

The overall end carboxy concentration of the stacked film is 6~17 equivalents/ton,

Described 1st layer of Chinese white concentration is 6~12 mass %.

2. stacked film according to claim 1, wherein,

Described 2nd layer of Chinese white concentration is 0~1.5 mass %.

3. stacked film according to claim 1, wherein,

In described 2nd layer, as raw material, the width end to the stacked film containing below 60 mass % is repaiied The recovery fragment cut and crushed, the recovery fragment is not included actually in described 1st layer.

4. stacked film according to claim 2, wherein,

In described 2nd layer, as raw material, the width end to the stacked film containing below 60 mass % is repaiied The recovery fragment cut and crushed, the recovery fragment is not included actually in described 1st layer.

5. according to stacked film according to any one of claims 1 to 4, wherein,

The stacked film is used for solar module.

6. a kind of solar module backboard, it includes stacked film according to any one of claims 1 to 4.

7. a kind of solar module, it includes the solar-electricity containing stacked film according to any one of claims 1 to 4 Pond module backboard.