JP2014121817A - Laminate film, back sheet for solar cell module, and solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate film unaccompanied by bleed-out of a ketene compound and capable of realizing high adhesiveness.SOLUTION: Provided is a laminate film including a polyester film and a polymer layer laminated adjacently on at least one surface of the polyester film, wherein the polyester film includes a polyester and a ketenimine compound, and wherein the polymer layer includes a binder having at least one type of functional group selected from among a carboxyl group, a hydroxyl group, an amino group, a sulfonate group, an isocyanate group, an epoxy group, a silanol group, and an alkoxysilyl group.

Description

  The present invention relates to a laminated film, a solar cell module backsheet, and a solar cell module.

  Generally, a solar cell module is formed by laminating glass or a front sheet / transparent filling material (sealing material) / solar cell element / sealing material / back sheet (BS) in this order from the light-receiving surface side on which sunlight enters. It has a structure. The solar cell element is generally embedded in a resin (sealing material) such as EVA (ethylene-vinyl acetate copolymer) and further has a structure in which a protective sheet for solar cell is attached thereon. Among the protective sheets for solar cells, the solar cell module back sheet (BS) disposed particularly on the outermost layer functions to protect the solar cell elements. When the solar cell module is installed in a roof, the backsheet (BS) is expected to be exposed to wind and rain or placed in a high temperature and humidity environment for a long period of time, and therefore excellent weather resistance is required.

  Conventionally, a polyester film, particularly a polyethylene terephthalate (hereinafter referred to as PET) film has been used as a back sheet for a solar cell module. Since the polyester film has excellent heat resistance, mechanical properties, chemical resistance, and the like, it is preferably used for a back sheet for a solar cell module. However, since these films have poor hydrolysis resistance, the molecular weight decreases due to hydrolysis, and the mechanical properties deteriorate due to progress of embrittlement. Therefore, these films can be used as back sheets for solar cells over a long period of time. The practical strength could not be maintained.

  Therefore, in order to improve the hydrolysis resistance of the polyester film, Patent Documents 1 and 2 propose that a ketene imine compound is added to the polyester film as an end-capping agent. Here, the ketene imine compound functions to suppress hydrolysis of the polyester by reacting with the terminal carboxyl group of the polyester.

US Pat. No. 3,692,745 JP-A-10-130482

However, when a polymer layer such as an easy-adhesion layer is laminated on a polyester film containing a ketene imine compound as in Patent Documents 1 and 2, the ketene compound produced by the reaction of the ketene imine compound and the terminal carboxyl group of the polyester is It became clear by the present inventors that it diffuses to the surface.
Such diffusion of the ketene compound is called ketene compound crying. When ketene compound crying occurs, not only the adhesion between the polymer layer and the polyester film is lowered, but also on the polymer layer. This causes a problem because the adhesion between the stacked adherends is also lowered.

  Therefore, in order to solve such a problem of the prior art, the present inventors suppressed the crying of the ketene compound when the polymer layer is laminated on the polyester film containing the ketene imine compound, and has high adhesion. Studies were conducted with the aim of providing a laminated film that can be used.

As a result of intensive studies to solve the above problems, the present inventors laminated a polymer layer containing a binder having a specific functional group on a polyester film containing a ketene imine compound having a specific structure. Thus, it was found that the crying of the ketene compound is suppressed. Thereby, in addition to improving the adhesion between the polymer layer and the polyester film, the present inventors can maintain good adhesion between the polymer layer and the adherend laminated thereon. The headline and the present invention have been completed.
Specifically, the present invention has the following configuration.

（一般式（１）中、Ｒ₁およびＲ₂は、それぞれ独立にアリール基、アリールオキシ基、アリールアミノカルボニル基、またはアリールオキシカルボニル基を表し、Ｒ₃はアルキル基またはアリール基を表す。）
［２］前記ケテンイミン化合物は下記一般式（２）で表されることを特徴とする［１］に記載の積層フィルム。

（一般式（２）中、Ｒ₁₁〜Ｒ₂₀は、それぞれ独立に水素原子、アルキル基、アリール基またはアルコキシ基を表す。Ｒ₁₁〜Ｒ₂₀は互いに結合して環を形成してもよい。Ｒ₃はアルキル基またはアリール基を表す。）
［３］前記ポリマー層は、カルボキシル基、エポキシ基およびアルコキシシリル基の中から選択される少なくとも１種の官能基を有するバインダーを含むことを特徴とする［１］または［２］に記載の積層フィルム。
［４］前記ケテンイミン化合物の添加率は、前記ポリエステルの総量に対して、０．１〜２質量％であることを特徴とする［１］〜［３］のいずれかに記載の積層フィルム。［５］前記ケテンイミン化合物１００質量部に対し、前記カルボキシル基、ヒドロキシル基、アミノ基、スルホン酸基、イソシアネート基、エポキシ基、シラノール基、およびアルコキシシリル基の中から選択される少なくとも１種の官能基を有するバインダーを０．１〜１０００質量部含有することを特徴とする［１］〜［４］のいずれかに記載の積層フィルム。
［６］２軸延伸されたことを特徴とする［１］〜［５］のいずれかに記載の積層フィルム。
［７］［１］〜［６］のいずれかに記載の積層フィルムを用いた太陽電池モジュール用バックシート。
［８］［７］に記載の太陽電池モジュール用バックシートを用いた太陽電池モジュール。
［９］ポリエステルと、下記一般式（１）で表されるケテンイミン化合物とを含む混合物を溶融させた溶融体を流涎して冷却固化させ、ポリエステルフィルムを得るフィルム形成工程と、前記ポリエステルフィルムを２軸方向に延伸する延伸工程と、前記２軸方向に延伸したポリエステルフィルムの少なくとも一方の面に、カルボキシル基、ヒドロキシル基、アミノ基、スルホン酸基、イソシアネート基、エポキシ基、シラノール基、およびアルコキシシリル基の中から選択される少なくとも１種の官能基を有するバインダーを含むポリマー層を形成する工程とを含むことを特徴とするポリエステルフィルムの製造方法。

（一般式（１）中、Ｒ₁およびＲ₂は、それぞれ独立にアリール基、アリールオキシ基、アリールアミノカルボニル基、またはアリールオキシカルボニル基を表し、Ｒ₃はアルキル基またはアリール基を表す。）
［１０］ポリエステルと、下記一般式（１）で表されるケテンイミン化合物とを含む混合物を溶融させた溶融体を流涎して冷却固化させ、ポリエステルフィルムを得るフィルム形成工程と、前記ポリエステルフィルムをＭＤ方向に延伸する延伸工程と、前記ＭＤ方向に延伸したポリエステルフィルムの少なくとも一方の面に、カルボキシル基、ヒドロキシル基、アミノ基、スルホン酸基、イソシアネート基、エポキシ基、シラノール基、およびアルコキシシリル基の中から選択される少なくとも１種の官能基を有するバインダーを含むポリマー層を形成する工程と、前記ポリマー層を積層したポリエステルフィルムをＴＤ方向に延伸する延伸工程とを含むことを特徴とするポリエステルフィルムの製造方法。

（一般式（１）中、Ｒ₁およびＲ₂は、それぞれ独立にアリール基、アリールオキシ基、アリールアミノカルボニル基、またはアリールオキシカルボニル基を表し、Ｒ₃はアルキル基またはアリール基を表す。） [1] A laminated film comprising a polyester film and a polymer layer laminated adjacent to at least one surface of the polyester film, wherein the polyester film is represented by polyester and the following general formula (1) And the polymer layer has at least one functional group selected from a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, an isocyanate group, an epoxy group, a silanol group, and an alkoxysilyl group. A laminated film containing a binder.

(In general formula (1), R ₁ and R ₂ each independently represents an aryl group, an aryloxy group, an arylaminocarbonyl group, or an aryloxycarbonyl group, and R ₃ represents an alkyl group or an aryl group.)
[2] The laminated film according to [1], wherein the ketene imine compound is represented by the following general formula (2).

(In the general formula (2), R _{11 to} R ₂₀ each independently represents a hydrogen atom, an alkyl group, an aryl group or an alkoxy group. R _{11 to} R ₂₀ may combine with each other to form a ring. R ₃ represents an alkyl group or an aryl group.)
[3] The laminate according to [1] or [2], wherein the polymer layer includes a binder having at least one functional group selected from a carboxyl group, an epoxy group, and an alkoxysilyl group. the film.
[4] The laminated film according to any one of [1] to [3], wherein the addition rate of the ketene imine compound is 0.1 to 2% by mass with respect to the total amount of the polyester. [5] At least one functional selected from the carboxyl group, hydroxyl group, amino group, sulfonic acid group, isocyanate group, epoxy group, silanol group, and alkoxysilyl group with respect to 100 parts by mass of the ketene imine compound. The laminated film according to any one of [1] to [4], which contains 0.1 to 1000 parts by mass of a binder having a group.
[6] The laminated film according to any one of [1] to [5], which is biaxially stretched.
[7] A solar cell module backsheet using the laminated film according to any one of [1] to [6].
[8] A solar cell module using the solar cell module backsheet according to [7].
[9] A film forming step for obtaining a polyester film by pouring a melt obtained by melting a mixture containing polyester and a ketene imine compound represented by the following general formula (1) to obtain a polyester film; A stretching step for stretching in the axial direction, and a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, an isocyanate group, an epoxy group, a silanol group, and alkoxysilyl on at least one surface of the polyester film stretched in the biaxial direction Forming a polymer layer containing a binder having at least one functional group selected from the group.

(In general formula (1), R ₁ and R ₂ each independently represents an aryl group, an aryloxy group, an arylaminocarbonyl group, or an aryloxycarbonyl group, and R ₃ represents an alkyl group or an aryl group.)
[10] A film forming step for obtaining a polyester film by pouring a melt obtained by melting a mixture containing polyester and a ketene imine compound represented by the following general formula (1) to cool and solidify the polyester film and MD A stretching process that stretches in the direction, and at least one surface of the polyester film stretched in the MD direction, a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, an isocyanate group, an epoxy group, a silanol group, and an alkoxysilyl group. A polyester film comprising: a step of forming a polymer layer containing a binder having at least one functional group selected from the inside; and a stretching step of stretching the polyester film laminated with the polymer layer in the TD direction. Manufacturing method.

(In general formula (1), R ₁ and R ₂ each independently represents an aryl group, an aryloxy group, an arylaminocarbonyl group, or an aryloxycarbonyl group, and R ₃ represents an alkyl group or an aryl group.)

  According to the present invention, a ketene compound starts to cry on the surface of a polymer layer by laminating a polymer layer containing a binder having a specific functional group on a polyester film containing a ketene imine compound having a specific structure. This can be suppressed. Thereby, the adhesiveness of a polymer layer and a polyester film can be improved. Furthermore, the adhesion between the polymer layer and the adherend laminated thereon can also be improved.

  Further, according to the present invention, even when a laminated film in which a polyester film and a polymer layer are laminated is placed under severe conditions of high temperature and high humidity, the ketene compound is prevented from crying on the surface of the polymer layer. Therefore, the adhesion of the laminated film can be maintained over a long period of time. For this reason, the laminated | multilayer film of this invention are used suitably as a solar cell module backsheet.

FIG. 1 is a cross-sectional view showing an example of the laminated film of the present invention. FIG. 2 is a cross-sectional view showing a state in which the laminated film of the present invention is bonded to an adherend such as an EVA film.

  Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on representative embodiments and specific examples, but the present invention is not limited to such embodiments. In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

(Laminated film)
The present invention relates to a laminated film including a polyester film and a polymer layer laminated adjacent to at least one surface of the polyester film. Here, the polyester film includes polyester and a ketene imine compound represented by the following general formula (1), and the polymer layer includes a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, an isocyanate group, an epoxy group, and a silanol group. And a binder having at least one functional group selected from alkoxysilyl groups.

Here, in the general formula (1), R ₁ and R ₂ each independently represents an aryl group, an aryloxy group, an arylaminocarbonyl group, or an aryloxycarbonyl group, and R ₃ represents an alkyl group or an aryl group. .

  In this invention, it can suppress that the ketene compound produced | generated in a polyester film begins to cry on the surface of a polymer layer by setting a laminated film as the said structure. Furthermore, in the present invention, crying of the ketene compound can be suppressed even when the laminated film is placed under severe conditions of high temperature and high humidity. Thereby, the adhesiveness of a polymer layer and a polyester film can be improved, and also the adhesiveness between the laminated film stuck via a polymer layer and an adherend can be improved. In particular, when the laminated film is used as a back sheet for a solar cell module, the adhesion between the laminated film and the EVA film can be improved, which is preferable.

  FIG. 1 shows an example of a laminated film 10 according to the present invention. A laminated film 10 shown in FIG. 1 has a two-layer structure in which a polyester film 2 and a polymer layer 3 are laminated on one surface of the polyester film 2. In addition, in FIG. 1, although 2 layer structure is shown as a preferable aspect, the polymer layer 3 may be provided in both surfaces of the polyester film 2, and another layer may be provided.

The laminated film 10 is bonded to other members of the solar cell module through the polymer layer 3. FIG. 2 shows a state in which the laminated film 10 is bonded to the EVA film 5 that is a member of the solar cell module.
In the conventional laminated film, the ketene compound is liberated in the polyester film 2 containing the ketene imine compound, and the ketene compound is not only at the interface between the polymer layer 3 and the polyester film 2 but also at the interface between the polymer layer 3 and the EVA film 5. It was spreading until. Such diffusion of the ketene compound is called crying of the ketene compound. In particular, when a ketene compound begins to cry on the interface between the polymer layer 3 and the EVA film 5, the adhesion between the polymer layer 3 and the EVA film 5 deteriorates, and when used over a long period of time, the polymer layer 3 and the EVA film 5 There was a problem that the film 5 peeled off.
However, in the present invention, the polymer layer 3 has at least one functional group selected from among a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, an isocyanate group, an epoxy group, a silanol group, and an alkoxysilyl group. Since the binder is included, diffusion of the ketene compound can be suppressed. This is considered that the above-mentioned binder adsorbs the ketene compound to prevent the ketene compound from crying out on the interface between the polymer layer 3 and the EVA film 5.

  Moreover, the laminated film of the present invention can suppress crying of the ketene compound even under high temperature and high humidity conditions. For this reason, the laminated film of the present invention is particularly suitably used for a solar cell module that is often used under severe conditions of high temperature and high humidity.

(Polyester film)
The laminated film of the present invention has a polyester film as a support. The polyester film used in the present invention contains polyester and a ketene imine compound. Moreover, as a ketene imine compound, if the ketene imine compound as represented by the said General formula (1) can be contained, it is. For this reason, the polyester film has excellent hydrolysis resistance.

  Although the thickness of the polyester film of this invention changes with uses, when using as a member of the solar cell module backsheet, it is preferable that it is 25-300 micrometers, and it is more preferable that it is 120-300 micrometers. By setting the thickness of the polyester film to the above lower limit value or more, sufficient mechanical strength can be obtained, and by making the thickness not more than the above upper limit value, a merit in cost can be obtained.

  The polyester film of the present invention is preferably stretched, more preferably biaxially stretched, and plane biaxially stretched is particularly preferable as compared with stretching such as tubular, and sequential biaxial stretching. It is particularly preferred that

  The polyester film may contain other additives without departing from the gist of the present invention, and examples of the additives include antioxidants and ultraviolet inhibitors.

<Polyester>
The polyester film used in the present invention contains polyester. The kind in particular of polyester is not restrict | limited, A well-known thing can be used as polyester.

  The polyester is preferably a saturated polyester. Thus, by using a saturated polyester, a polyester film that is superior in terms of mechanical strength as compared with a film using an unsaturated polyester can be obtained. Examples of the polyester include a linear saturated polyester synthesized from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof.

  Specific examples of the linear saturated polyester include polyethylene terephthalate (PET), polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylenedimethylene terephthalate), and polyethylene-2,6-naphthalate. Among these, polyethylene terephthalate (PET) or polyethylene-2,6-naphthalate (PEN) is particularly preferable in terms of a balance between mechanical properties and cost, and polyethylene terephthalate is more particularly preferable.

  The polyester may be a homopolymer or a copolymer. Further, polyester may be blended with a small amount of other types of resin, such as polyimide. Further, as the polyester, a crystalline polyester capable of forming anisotropy when melted may be used.

  From the viewpoint of heat resistance and viscosity, the molecular weight of the polyester is preferably 5000 to 30000, more preferably 8000 to 26000, and particularly preferably 12,000 to 24,000. As the weight average molecular weight of the polyester, a value in terms of polymethyl methacrylate (PMMA) measured by gel permeation chromatography (GPC) using hexafluoroisopropanol as a solvent can be used.

  The polyester can be obtained by reacting a dicarboxylic acid or an ester-forming derivative thereof with a low molecular weight aliphatic diol or a high molecular weight diol. Examples of the dicarboxylic acid or its ester-forming derivative include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalene dicarboxylic acid, paraphenylene dicarboxylic acid, dimethyl terephthalate, dimethyl isophthalate, dimethyl orthophthalate, dimethyl naphthalene dicarboxylate, and paraphenylene. And dimethyl dicarboxylate. These may be used alone or in combination of two or more.

Examples of the low molecular weight aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, and 1,5-pentane. Examples include diol, 1,6-hexanediol, 1,4-cyclohexanedimethanol and the like. These may be used alone or in combination of two or more.
Examples of the high molecular weight diol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol and the like. These may be used alone or in combination of two or more.

Examples of the crystalline polyester composed of the above components include polyethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, butanediol terephthalate polytetramethylene glycol copolymer, and the like. . These may be used alone or in combination of two or more.
Particularly preferred among aromatic polyesters are those using terephthalic acid and naphthalenedicarboxylic acid as main components as dicarboxylic acids, and those having ethylene glycol and cyclohexanedimethanol as main components as diols, more preferably polyethylene terephthalate. Polyethylene naphthalate and polycyclohexanedimethylene terephthalate, more preferably polyethylene terephthalate and polyethylene naphthalate.

  Polyester can be synthesized by a known method. For example, polyester can be synthesized by a known polycondensation method or ring-opening polymerization method, and any of transesterification and direct polymerization can be applied.

  When the polyester used in the present invention is a polymer or copolymer obtained by a condensation reaction mainly comprising an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof, An aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof can be produced by an esterification reaction or an ester exchange reaction and then a polycondensation reaction. Moreover, the carboxylic acid value and intrinsic viscosity of the polyester can be controlled by selecting the raw material and reaction conditions. In order to effectively advance the esterification reaction or transesterification reaction and polycondensation reaction, it is preferable to add a polymerization catalyst during these reactions.

  As a polymerization catalyst for polymerizing polyester, Sb-based, Ge-based, and Ti-based compounds are preferably used from the viewpoint of suppressing the carboxyl group content to a predetermined range or less, and Ti-based compounds are particularly preferable. In the case of using a Ti-based compound, an embodiment in which polymerization is performed by using the Ti-based compound as a catalyst in the range of 1 to 30 ppm, more preferably 3 to 15 ppm is preferable. When the proportion of the Ti-based compound is within the above range, the terminal carboxyl group can be adjusted to the following range, and the hydrolysis resistance of the polymer substrate can be kept low.

  Examples of the synthesis of polyester using a Ti compound include Japanese Patent Publication No. 8-301198, Japanese Patent No. 2543624, Japanese Patent No. 3335683, Japanese Patent No. 3717380, Japanese Patent No. 3997756, Japanese Patent No. 3996226, Japanese Patent No. 3997866, Japanese Patent No. 39968671, The methods described in Japanese Patent No. 40000867, Japanese Patent No. 4053837, Japanese Patent No. 4127119, Japanese Patent No. 4134710, Japanese Patent No. 4159154, Japanese Patent No. 4269704, Japanese Patent No. 431538, and the like can be applied.

  The polyester is preferably solid-phase polymerized after polymerization. Thereby, a preferable carboxylic acid value can be achieved. Solid-phase polymerization may be a continuous method (a method in which a tower is filled with a resin, which is slowly heated for a predetermined time and then sent out), or a batch method (a resin is charged into a container). , A method of heating for a predetermined time). Specifically, solid-phase polymerization is described in Japanese Patent No. 2621563, Japanese Patent No. 3121876, Japanese Patent No. 3136774, Japanese Patent No. 3603585, Japanese Patent No. 3616522, Japanese Patent No. 3617340, Japanese Patent No. 3680523, Japanese Patent No. 3717392, Japanese Patent No. 4167159, etc. The method can be applied.

  The temperature of the solid phase polymerization is preferably 170 to 240 ° C, more preferably 180 to 230 ° C, and further preferably 190 to 220 ° C. The solid phase polymerization time is preferably 5 to 100 hours, more preferably 10 to 75 hours, and further preferably 15 to 50 hours. The solid phase polymerization is preferably performed in a vacuum or in a nitrogen atmosphere.

<Ketene imine compound>
The polyester film of the present invention contains a ketene imine compound. The ketene imine compound may be used alone or in combination with other end-capping agents such as carbodiimide compounds.
As the ketene imine compound, a ketene imine compound represented by the following general formula (1) is preferably used. Hereinafter, the ketene imine compound represented by the following general formula (1) will be described.

Here, in the general formula (1), R ₁ and R ₂ each independently represents an aryl group, an aryloxy group, an arylaminocarbonyl group, or an aryloxycarbonyl group, and R ₃ represents an alkyl group or an aryl group. .

The aryl group represented by R ₁ and R ₂ is preferably an aryl group having 6 to 20 carbon atoms, and more preferably an aryl group having 6 to 12 carbon atoms. Examples of the aryl group represented by R ₁ and R ₂ include a phenyl group and a naphthyl group, and among them, a phenyl group is particularly preferable.
The aryl group includes a heteroaryl group. The heteroaryl group refers to a group in which at least one of the ring-constituting atoms of a 5-membered, 6-membered or 7-membered ring exhibiting aromaticity or a condensed ring thereof is substituted with a heteroatom. Examples of the heteroaryl group include imidazolyl group, pyridyl group, quinolyl group, furyl group, thienyl group, benzoxazolyl group, indolyl group, benzimidazolyl group, benzthiazolyl group, carbazolyl group, and azepinyl group. . The hetero atom contained in the heteroaryl group is preferably an oxygen atom, a sulfur atom, or a nitrogen atom, and particularly preferably an oxygen atom or a nitrogen atom.
The aryl group or heteroaryl group represented by R ₁ and R ₂ may further have a substituent, and the substituent is not particularly limited as long as the reactivity between the ketene imine group and the carboxyl group is not lowered. The carbon number of the aryl group or heteroaryl group represented by R ₁ and R ₂ is the number of carbons not including a substituent.

The aryloxy group represented by R ₁ and R ₂ is preferably an aryloxy group having 6 to 20 carbon atoms, and more preferably an aryloxy group having 6 to 12 carbon atoms. Examples of the aryl moiety of the aryloxy group represented by R ₁ and R ₂ include the examples of the aryl group or heteroaryl group described above. The aryloxy group represented by R ₁ and R ₂ may further have a substituent, and the substituent is not particularly limited as long as the reactivity between the ketene imine group and the carboxyl group is not lowered. In addition, carbon number of the aryloxy group which R < ₁ > and R < ₂ > represent shows carbon number which does not contain a substituent.

The arylaminocarbonyl group represented by R ₁ and R ₂ is preferably an arylaminocarbonyl group having 6 to 20 carbon atoms. Preferable examples of the arylamino moiety of the arylaminocarbonyl group having 6 to 20 carbon atoms include a group in which —NH— is linked to the terminal of the aryl group represented by R ₁ and R ₂ . Examples of the aryl moiety of the arylaminocarbonyl group represented by R ₁ and R ₂ include the examples of the aryl group or heteroaryl group described above. The arylaminocarbonyl group represented by R ₁ and R ₂ may further have a substituent, and the substituent is not particularly limited as long as the reactivity between the ketene imine group and the carboxyl group is not lowered. In addition, carbon number of the arylaminocarbonyl group which R < ₁ > and R < ₂ > represent shows carbon number which does not contain a substituent.

Aryloxycarbonyl group represented by R ₁ and R ₂ is preferably an aryloxycarbonyl group having 7 to 20 carbon atoms, more preferably R ₁ and be an aryloxycarbonyl group having 7 to 12 carbon atoms Examples of the aryl moiety of the aryloxycarbonyl group represented by R ₂ include the above-described aryl groups and heteroaryl groups. The aryloxycarbonyl group represented by R ₁ and R ₂ may further have a substituent, and the substituent is not particularly limited as long as the reactivity between the ketene imine group and the carboxyl group is not lowered. In addition, the carbon number of the aryloxycarbonyl group which R < ₁ > and R < ₂ > represent shows the carbon number which does not contain a substituent.

In the general formula (1), R ₁ and R ₂ each independently represents an aryl group, an aryloxy group, an arylaminocarbonyl group, or an aryloxycarbonyl group, but the ketene imine represented by the general formula (1) The compound may be used in combination with a ketene imine compound in which R ₁ and R ₂ are an alkyl group, an alkoxy group, an alkoxycarbonyl group, an aminocarbonyl group, or an acyl group. In this case, the ratio of the ketene imine compound represented by the general formula (1) to the total amount of the ketene imine compound is preferably 80% or more, more preferably 90% or more, and 100%. Is particularly preferred.

The alkyl group represented by R ₁ and R ₂ is preferably an alkyl group having 1 to 20 carbon atoms, and more preferably an alkyl group having 1 to 12 carbon atoms. The alkyl group represented by R ₁ and R ₂ may be linear, branched or cyclic. Examples of the alkyl group represented by R ₁ and R ₂ include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, tert-butyl group, sec-butyl group, iso-butyl group, n- A pentyl group, a sec-pentyl group, an iso-pentyl group, an n-hexyl group, a sec-hexyl group, an iso-hexyl group, a cyclohexyl group, and the like can be given. Of these, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an iso-butyl group, and a cyclohexyl group are more preferable.
The alkyl group represented by R ₁ and R ₂ may further have a substituent. Unless the reactivity of a ketene imine group and a carboxyl group is lowered, the substituent is not particularly limited, and the above substituents can be exemplified similarly. In addition, carbon number of the alkyl group which R < ₁ > and R < ₂ > represent shows carbon number which does not contain a substituent.

The alkoxy group represented by R ₁ and R ₂ is preferably an alkoxy group having 1 to 20 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, and an alkoxy group having 2 to 6 carbon atoms. It is particularly preferred that The alkoxy group represented by R ₁ and R ₂ may be linear, branched or cyclic. Preferable examples of the alkoxy group represented by R ₁ and R ₂ include a group in which —O— is linked to the terminal of the alkyl group represented by R ₁ and R ₂ . The alkoxy group represented by R ₁ and R ₂ may further have a substituent, and the substituent is not particularly limited as long as the reactivity between the ketene imine group and the carboxyl group is not lowered. In addition, carbon number of the alkoxy group which R < ₁ > and R < ₂ > represent shows carbon number which does not contain a substituent.

The alkoxycarbonyl group represented by R ₁ and R ₂ is preferably an alkoxycarbonyl group having 2 to 20 carbon atoms, more preferably an alkoxycarbonyl group having 2 to 12 carbon atoms, and 2 to 6 carbon atoms. Particularly preferred is an alkoxycarbonyl group. Examples of the alkoxy moiety of the alkoxycarbonyl group represented by R ₁ and R ₂ include the examples of the alkoxy group described above. The alkoxycarbonyl group represented by R ₁ and R ₂ may further have a substituent, and the substituent is not particularly limited as long as the reactivity between the ketene imine group and the carboxyl group is not lowered. In addition, carbon number of the alkoxycarbonyl group which R < ₁ > and R < ₂ > represent shows carbon number which does not contain a substituent.

The aminocarbonyl group represented by R ₁ and R ₂ is preferably an alkylaminocarbonyl group having 1 to 20 carbon atoms, more preferably an alkylaminocarbonyl group having 2 to 12 carbon atoms, and 2 carbon atoms. Particularly preferred is an alkylaminocarbonyl group of ˜6. Preferable examples of the alkylamino part of the alkylaminocarbonyl group include a group in which —NH— is linked to the terminal of the alkyl group represented by R ₁ and R ₂ . The alkylaminocarbonyl group represented by R ₁ and R ₂ may further have a substituent, and the substituent is not particularly limited as long as the reactivity between the ketene imine group and the carboxyl group is not lowered. In addition, carbon number of the alkylaminocarbonyl group which R < ₁ > and R < ₂ > represent shows carbon number which does not contain a substituent.

The acyl group represented by R ₁ and R ₂ is preferably an acyl group having 2 to 20 carbon atoms, more preferably an acyl group having 2 to 12 carbon atoms, and an acyl group having 2 to 6 carbon atoms. It is particularly preferred that The acyl group represented by R ₁ and R ₂ may further have a substituent, and the substituent is not particularly limited as long as the reactivity between the ketene imine group and the carboxyl group is not lowered. In addition, carbon number of the acyl group which R < ₁ > and R < ₂ > represent shows carbon number which does not contain a substituent.

R ₃ represents an alkyl group or an aryl group. The alkyl group is preferably an alkyl group having 1 to 20 carbon atoms, and more preferably an alkyl group having 1 to 12 carbon atoms. The alkyl group represented by R ₃ may be linear, branched or cyclic. Examples of the alkyl group represented by R ₃ include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a tert-butyl group, a sec-butyl group, an iso-butyl group, an n-pentyl group, A sec-pentyl group, an iso-pentyl group, an n-hexyl group, a sec-hexyl group, an iso-hexyl group, a cyclohexyl group, and the like can be given. Of these, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, and a cyclohexyl group are more preferable.
The alkyl group represented by R ₃ may further have a substituent. Unless the reactivity of a ketene imine group and a carboxyl group is lowered, the substituent is not particularly limited, and the above substituents can be exemplified similarly.

The aryl group is preferably an aryl group having 6 to 20 carbon atoms, and more preferably an aryl group having 6 to 12 carbon atoms. Examples of the aryl group represented by R ₃ include a phenyl group and a naphthyl group, and among them, a phenyl group is particularly preferable.
The aryl group includes a heteroaryl group. The heteroaryl group refers to a group in which at least one of the ring-constituting atoms of a 5-membered, 6-membered or 7-membered ring exhibiting aromaticity or a condensed ring thereof is substituted with a heteroatom. Examples of the heteroaryl group include imidazolyl group, pyridyl group, quinolyl group, furyl group, thienyl group, benzoxazolyl group, indolyl group, benzimidazolyl group, benzthiazolyl group, carbazolyl group, and azepinyl group. . The hetero atom contained in the heteroaryl group is preferably an oxygen atom, a sulfur atom, or a nitrogen atom, and particularly preferably an oxygen atom or a nitrogen atom.
The aryl group or heteroaryl group represented by R ₃ may further have a substituent, and the substituent is not particularly limited as long as the reactivity between the ketene imine group and the carboxyl group is not lowered.

In addition, General formula (1) may contain the repeating unit. In this case, at least one of R _{1 and} R ₃ is a repeating unit, and this repeating unit preferably contains a ketene imine moiety.

The molecular weight of the portion excluding the nitrogen atom constituting the ketene imine of the ketene imine compound and the substituent bonded to the nitrogen atom is preferably 320 or more. That is, in the general formula (1), the molecular weight of the R ₁ —C (═C) —R ₂ group is preferably 320 or more. The molecular weight of the portion excluding the nitrogen atom of the ketene imine compound and the substituent bonded to the nitrogen atom is preferably 320 or more, more preferably 500 to 1500, and even more preferably 600 to 1000. .
Thus, the ketene imine compound and the ketene compound are stably present in the polyester film by setting the molecular weight of the portion excluding the nitrogen atom constituting the ketene imine and the substituent bonded to the nitrogen atom within the above range. be able to. In addition, by setting the ketene imine compound to a certain molecular weight, not only the ketene compound is volatilized but also the volatilization of the ketene imine compound can be suppressed in the process of forming a polyester film.
Moreover, when a polymer layer is laminated | stacked on a polyester film by making molecular weight into the said range, adhesiveness with a polymer layer can be improved. This is because when the ketene imine compound has a molecular weight within a certain range, the polyester terminal can be made bulky, and the polyester terminal diffuses into the polymer layer and exhibits the anchoring effect.

  Moreover, as a ketene imine compound, it is preferable to use the ketene imine compound represented by following General formula (2). Hereinafter, the ketene imine compound represented by the following general formula (2) will be described.

Here, in the general formula (2), R _{11 to} R ₂₀ each independently represents a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. R _{11 to} R ₂₀ may be bonded to each other to form a ring. R ₃ represents an alkyl group or an aryl group.

In General Formula (2), R _{11 to} R ₂₀ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group, and each represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. It is preferably a group, more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and particularly preferably a hydrogen atom.

The alkyl group represented by R _{11 to} R ₂₀ is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, and an alkyl group having 2 to 6 carbon atoms. It is particularly preferred. The alkyl group represented by R _{11 to} R ₂₀ may be linear, branched or cyclic. Examples of the alkyl group represented by R _{11 to} R ₂₀ include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, tert-butyl group, sec-butyl group, iso-butyl group, n- A pentyl group, a sec-pentyl group, an iso-pentyl group, an n-hexyl group, a sec-hexyl group, an iso-hexyl group, a cyclohexyl group, and the like can be given. Of these, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an iso-butyl group, and a cyclohexyl group are more preferable.

The aryl group represented by R _{11 to} R ₂₀ is preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 12 carbon atoms, and an aryl group having 6 carbon atoms. Particularly preferred. Examples of the aryl group represented by R _{11 to} R ₂₀ include a phenyl group and a naphthyl group, and among them, a phenyl group is particularly preferable.
The aryl group includes a heteroaryl group. The heteroaryl group refers to a group in which at least one of the ring-constituting atoms of a 5-membered, 6-membered or 7-membered ring exhibiting aromaticity or a condensed ring thereof is substituted with a heteroatom. Examples of the heteroaryl group include imidazolyl group, pyridyl group, quinolyl group, furyl group, thienyl group, benzoxazolyl group, indolyl group, benzimidazolyl group, benzthiazolyl group, carbazolyl group, and azepinyl group. . The hetero atom contained in the heteroaryl group is preferably an oxygen atom, a sulfur atom, or a nitrogen atom, and particularly preferably an oxygen atom or a nitrogen atom.

The alkoxy group represented by R _{11 to} R ₂₀ is preferably an alkoxy group having 1 to 20 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, and an alkoxy group having 2 to 6 carbon atoms. It is particularly preferred. The alkoxy group represented by R ¹ and R ⁵ may be linear, branched or cyclic. Preferable examples of the alkoxy group represented by R _{11 to} R ₂₀ include a group in which —O— is linked to the terminal of the alkyl group represented by R _{11 to} R ₂₀ .

The alkyl group, aryl group or alkoxy group represented by R _{11 to} R ₂₀ may further have a substituent, and the substituent is not particularly limited.

In the general formula (2), R _{11 to} R ₂₀ may be bonded to each other to form a ring. The ring formed at this time is not particularly limited, but is preferably an aromatic ring. For example, two or more of R _{11 to} R ₁₅ may be bonded to each other to form a condensed ring, and an arylene group or heteroarylene group having 10 or more carbon atoms is formed with a benzene ring substituted by R _{11 to} R _15. May be. Examples of the arylene group having 10 or more carbon atoms formed at this time include aromatic groups having 10 to 15 carbon atoms such as naphthalenediyl group.
Similarly, for example, two or more of R _{16 to} R ₂₀ may be bonded to each other to form a condensed ring, and an arylene group or heteroarylene having 10 or more carbon atoms together with a benzene ring substituted by R _{16 to} R _20. The preferred range at that time is the same as the preferred range when an arylene group or heteroarylene group having 10 or more carbon atoms is formed together with the benzene ring substituted by R _{16 to} R ₂₀ .
However, in the ketene imine compound of the present invention, in the general formula (2), it is preferable that R _{11 to} R ₂₀ are not bonded to each other to form a ring.

  As the ketene imine compound, a ketene imine compound represented by the following general formula (3) may be used. Hereinafter, the ketene imine compound represented by the following general formula (3) will be described.

Here, in general formula (3), R ₁ is preferably an aryl group, an aryloxy group, an arylaminocarbonyl group, or an aryloxycarbonyl group, and is an alkyl group, an alkoxy group, an alkoxycarbonyl group, an aminocarbonyl group, or an acyl group. It may be a group. R ₂ is preferably an aryl group having L ₁ as a substituent, an aryloxy group, an arylaminocarbonyl group, or an aryloxycarbonyl group, and an alkyl group, an alkoxy group, an alkoxycarbonyl group having L ₁ as a substituent, It may be an aminocarbonyl group or an acyl group. R ₃ represents an alkyl group or an aryl group. n represents an integer of 1 to 4, and L ₁ represents an n-valent linking group. The molecular weight of the (R ₁ —C (═C) —R ₂ —) nL ₁ group is preferably 320 or more.

In general formula (3), R ₁ is the same as that in general formula (1), and the preferred range is also the same.

In the general formula (3), R ₂ represents an aryl group having L ₁ is an n-valent linking group, aryloxy group, arylamino group or preferably an aryloxycarbonyl group,, L ₁ as a substituent An alkyl group having an alkyl group, an alkoxy group, an alkoxycarbonyl group, an aminocarbonyl group, or an acyl group may be used. The aryl group, aryloxy group, arylaminocarbonyl group, aryloxycarbonyl group, alkyl group, alkoxy group, alkoxycarbonyl group, aminocarbonyl group or acyl group are the same as those in the general formula (1), and the preferred range is also It is the same.

In general formula (3), R ₃ is the same as that in general formula (1), and the preferred range is also the same.

L ₁ represents an n-valent linking group, where n represents an integer of 1 to 4. Especially, it is preferable that n is 2-4.
Specific examples of the divalent linking group include, for example, —NR ₈ — (R ₈ represents a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent, A hydrogen atom is preferred), —SO ₂ —, —CO—, a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkenylene group, an alkynylene group, a substituted or unsubstituted phenylene group, substituted or unsubstituted Examples thereof include a substituted biphenylene group, a substituted or unsubstituted naphthylene group, -O-, -S- and -SO-, and a group obtained by combining two or more thereof.
Specific examples of the trivalent linking group include a group obtained by removing one hydrogen atom from those having a substituent among the linking groups mentioned as examples of the divalent linking group.
Specific examples of the tetravalent linking group include, for example, a group obtained by removing two hydrogen atoms from those having a substituent among the linking groups mentioned as examples of the divalent linking group.

  In the present invention, by setting n to 2 to 4, a compound having two or more ketene imine moieties in one molecule can be obtained, and a more excellent end-capping effect can be exhibited. Further, by using a compound having two or more ketene imine moieties in one molecule, the molecular weight per ketene imine group can be lowered, and the ketene imine compound and the terminal carboxyl group of the polyester can be reacted efficiently. Furthermore, it can suppress that a ketene imine compound and a ketene compound volatilize by having two or more ketene imine parts in 1 molecule.

  In general formula (3), n is more preferably 3 or 4. By setting n to 3 or 4, a compound having 3 or 4 ketene imine moieties in one molecule can be obtained, and a more excellent end-capping effect can be exhibited.

  As the ketene imine compound, a ketene imine compound represented by the following general formula (4) may be used. Hereinafter, the ketene imine compound represented by the following general formula (4) will be described.

In general formula (4), R ₁ and R ₅ are preferably an aryl group, an aryloxy group, an arylaminocarbonyl group, or an aryloxycarbonyl group, and are an alkyl group, an alkoxy group, an alkoxycarbonyl group, an aminocarbonyl group, or It may be an acyl group. R ₂ and R ₄ are aryl groups having L ₂ as a substituent group, an aryloxy group, an arylamino group or preferably an aryloxycarbonyl group, an alkyl group having L ₂ as a substituent group, an alkoxy group, an alkoxy It may be a carbonyl group, an aminocarbonyl group or an acyl group. R ₃ and R ₆ represent an alkyl group or an aryl group. L ₂ represents a single bond or a divalent linking group. _{R 1 -C (= C) -R} 2 -L 2 -R 4 -C (= C) molecular weight of -R ₅ groups is preferably 320 or more.

In general formula (4), R ₁ is the same as that in general formula (1), and the preferred range is also the same. R ₅ is the same as R ₁ in the general formula (1), and the preferred range is also the same.

In general formula (4), R ₂ is the same as that in general formula (3), and the preferred range is also the same. R ₄ is the same as R ₂ in formula (3), and the preferred range is also the same.

In general formula (4), R ₃ is the same as that in general formula (1), and the preferred range is also the same. R ₆ is the same as R ₃ in the general formula (1), and the preferred range is also the same.

In General Formula (4), L ₂ represents a single bond or a divalent linking group. Specific examples of the divalent linking group include the linking groups exemplified for L ₁ in formula (3).

  The ketene imine compound of the present invention is a compound having at least one ketene imine group. Am. Chem. Soc. 1953, 75 (3), pp 657-660, and the like.

  Although the preferable specific example of General formula (1) is shown below, this invention is not limited to this.

  It is preferable to add a ketene imine compound so that it may become 0.05-5 mass% with respect to polyester, It is more preferable to add so that it may become 0.05-3 mass%, 0.1-2 mass It is more preferable to add so that it may become%. Thus, the hydrolysis resistance of a polyester film can be effectively improved by making the addition rate of a ketene imine compound into the said range.

  The polyester film of the present invention does not refuse to contain a ketene imine compound other than the ketene imine compound of the present invention unless it is contrary to the spirit of the present invention, but 90% of the ketene imine compound contained in the polyester film of the present invention. The above is preferably the ketene imine compound of the present invention, more preferably 95% or more is the ketene imine compound of the present invention, and 100% is particularly preferably the ketene imine compound of the present invention.

It is preferable that the ketene imine compound is reacted in an amount of 5 to 99%, preferably 10 to 90%, more preferably 20 to 80%. If the reaction rate is too low, the hydrolysis resistance is deteriorated. If the reactivity is too high, the viscosity may increase and film formation may be difficult.
The reaction rate of the ketene imine compound can be obtained from the IR spectrum of the polyester film and can be calculated from the peak at 2000 cm ⁻¹ .

(Polymer layer)
The laminated film of the present invention has a polymer layer. The polymer layer used in the present invention is provided on at least one surface of the above-described polyester film, and functions as an easy adhesion layer that bonds the polyester film and the EVA film. The polymer layer includes a binder having at least one functional group selected from among a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, an isocyanate group, an epoxy group, a silanol group, and an alkoxysilyl group.

  These binders react with the ketene compound in the polymer layer and function to adsorb the ketene compound. For this reason, in the polyester film, the ketene compound produced | generated when a ketene imine compound reacts with the terminal carboxyl group of polyester can be adsorb | sucked. Thereby, it is possible to prevent the ketene compound from diffusing to the surface of the polymer layer, and it is possible to suppress crying of the ketene compound.

  As the binder, among the binders described above, those having at least one selected from a carboxyl group, a hydroxyl group, an amino group, an isocyanate group, an epoxy group and an alkoxysilyl group as a functional group are more preferably used. Those having a group as a functional group are particularly preferably used. Since the binder having these functional groups easily adsorbs to the ketene compound in the polymer layer, the ketene compound can be effectively prevented from crying out on the surface of the polymer layer.

  It is preferable that 0.1-1000 mass parts is contained with respect to 100 mass parts of ketene imine compounds contained in a polyester film, and the binder which has a specific functional group as mentioned above contains 0.5-800 mass parts. It is more preferable that 1 to 500 parts by mass is contained. By containing a binder having a specific functional group so as to be within the above range with respect to 100 parts by mass of the ketene imine compound, the ketene compound produced in the polyester film can be adsorbed efficiently, and the crying of the ketene compound It is possible to effectively suppress the ejection.

  The number of functional groups contained in the binder is preferably 1 to 99 mol%, preferably 5 to 50 mol%, more preferably 5 to 40 mol% in one molecule.

  The binder having a specific functional group as described above is preferably composed of polyolefin, polyacryl, polyurethane, polyester, or rubber resin. Such a binder can be obtained by homopolymerizing or copolymerizing a monomer having a specific functional group.

<Polyolefin resin>
As the polyolefin resin, it is also preferable to use a polyvinyl alcohol (PVA) resin. This is because when the polyester film produced according to the present invention is used as a solar battery back sheet, if a polymer layer containing a PVA resin is provided, it has a high affinity with the polyvinyl alcohol resin laminated on the polymer layer. is there. As an example of a commercial item, PVA105 (Kuraray Co., Ltd. product) etc. are mentioned.
Moreover, as polyolefin resin other than PVA, a modified polyolefin copolymer is preferable, for example. Commercially available products may be used as the polyolefin resin. For example, Arrow Base SE-1013N, SD-1010, TC-4010, TD-4010 (manufactured by Unitika Ltd.), Hitech S3148, S3121, S8512. (Manufactured by Toho Chemical Co., Ltd.), Chemipearl S-120, S-75N, V100, EV210H (manufactured by Mitsui Chemicals, Inc.) and the like. Among them, in the present invention, it is preferable to use Arrow Base SE-1013N, manufactured by Unitika Co., Ltd., which is a terpolymer of low density polyethylene, acrylic acid ester, and maleic anhydride. .

For these olefin resins, polyester resins (for example, Vylonal MD-1245 (manufactured by Toyobo Co., Ltd.)) can be preferably used. It is also preferable to add a polyurethane resin. For example, a carbonate-based urethane resin is preferable. For example, Superflex 460 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) can be preferably used.
These polyolefin resins may be used alone or in combination of two or more. When two or more of these polyolefin resins are used in combination, a combination of an acrylic resin and a polyolefin resin is preferable.

<Polyacrylic resin>
Polyacryl is obtained by copolymerizing the monomers exemplified below. That is, alkyl acrylate, alkyl methacrylate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, 2-ethylhexyl, cyclohexyl, etc.); Hydroxy-containing monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate and 2-hydroxypropyl methacrylate; Epoxy group-containing monomers such as glycidyl acrylate, glycidyl methacrylate and allyl glycidyl ether; acrylic acid and methacrylic acid Carboxylic acids such as itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene sulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.) A monomer having a group or a salt thereof; acrylamide, methacrylamide, N-alkyl acrylamide, N-alkyl methacrylamide, N, N-dialkyl acrylamide, N, N-dialkyl methacrylate (the alkyl group includes a methyl group, an ethyl group, n -Propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, 2-ethylhexyl group, cyclohexyl group, etc.), N-alkoxyacrylamide, N-alkoxymethacrylamide, N, N-dialkoxyacrylamide, N , N-dialkoxymethacrylamide (alkoxy groups include methoxy, ethoxy, butoxy, isobutoxy, etc.), acryloylmorpholine, N-methylolacrylamide, N-methylolmethacrylamide, N-phenol Monomers having an amide group such as ruacrylamide and N-phenylmethacrylamide; monomers of acid anhydrides such as maleic anhydride and itaconic anhydride; 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline Oxazolines such as 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline Group-containing monomers: methoxydiethylene glycol methacrylate, methoxypolyethylene glycol methacrylate, vinyl isocyanate, allyl isocyanate, styrene, α-methylstyrene, vinyl methyl ether, vinyl ethyl ether, vinyl trialkoxysilane, alkyl maleic acid Monoester, alkyl fumaric acid monoesters, alkyl itaconic acid monoester, acrylonitrile, methacrylonitrile, vinylidene chloride, ethylene, propylene, vinyl chloride, vinyl acetate, butadiene.
Examples of commercially available acrylic resins include Julimer ET-410 and SEK-301 (manufactured by Nippon Pure Chemical Industries, Ltd.). Examples of the composite resin of acrylic and silicone include Ceranate WSA1060, WSA1070 (manufactured by DIC Corporation), H7620, H7630, H7650 (manufactured by Asahi Kasei Chemicals Corporation) and the like.
As an example of the commercial item containing an epoxy group, Nipol SX1105 (made by Nippon Zeon Co., Ltd.) etc. are mentioned.

<Polyurethane resin>
Polyurethane is composed of polyol, polyisocyanate, chain extender, crosslinking agent and the like. Examples of polyols include polyoxyethylene glycol, polyoxypropylene glycol, polyethers such as polyoxytetramethylene glycol, polyethylene adipate, polyethylene-butylene adipate, polycaprolactone, and the like by a dehydration reaction of dicarboxylic acid. There are polyesters to be produced, polycarbonates having carbonate bonds, acrylic polyols, castor oil and the like. Examples of polyisocyanates include tolylene diisocyanate, phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and the like. Examples of chain extenders or crosslinking agents include ethylene glycol, propylene glycol, diethylene glycol, trimethylolpropane, hydrazine, ethylenediamine, diethylenetriamine, triethylenetetramine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodicyclohexylmethane, Water etc. are mentioned.

<Polyester resin>
Examples of the polyester resin include polyester resins obtained by polymerizing polyester monomers as exemplified below.
As polyester, the polyester obtained from the following polybasic acid component and diol component can be used. That is, as the polyvalent base component, for example, terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, Examples include pyromellitic acid, dimer acid, and 5-sodium sulfoisophthalic acid. As the polyester constituting the polymer binder, it is preferable to use a copolymerized polyester using two or more kinds of dicarboxylic acid components. The polyester may contain an unsaturated polybasic acid component such as maleic acid or itaconic acid, or a hydroxycarboxylic acid component such as p-hydroxybenzoic acid, if it is in a slight amount.

  Polyester diol components include ethylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylene glycol, dimethylolpropane, and the like, poly (ethylene oxide) ) Glycol and poly (tetramethylene oxide) glycol.

  The polymer layer may further contain a wetting agent, an antistatic agent, a colorant, a surfactant, an ultraviolet absorber and the like. When it contains a wetting agent, the content is 1-20 mass% with respect to solid content, for example.

  The thickness of the polymer layer is 10 to 500 nm. The thickness of the polymer layer may be 10 to 500 nm, preferably 20 to 300 nm, and more preferably 30 to 120 nm. In addition, the thickness of a polymer layer means the average film thickness of a polymer layer. By setting the thickness of the polymer layer within the above range, the adhesion between the polyester film and the polymer layer can be sufficiently enhanced. Moreover, the adsorption reaction of the ketene compound produced | generated in the binder contained in a polymer layer and a polyester film can be accelerated | stimulated by making the thickness of a polymer layer into the said range. Thereby, it can suppress that a ketene compound begins to cry on the surface of a polymer layer.

(Laminated film manufacturing method)
Below, each process of the manufacturing method of the laminated | multilayer film of this invention is demonstrated in detail.

<Film formation process>
In the film formation step, an unstretched polyester film can be formed by cooling and solidifying a melt obtained by melting the mixture used in the present invention and the ketene imine compound described above.
The melting temperature at the time of melting is preferably 120 to 350 ° C, more preferably 150 to 320 ° C, and further preferably 180 to 300 ° C. By setting the melting temperature within the above range, the reactivity of each of the polyester and the ketene imine compound can be increased.

  The melt is preferably passed through a gear pump or a filter, and the melt that has passed through the filter is extruded through a die to a cooling roll and cooled and solidified. The extruded melt can be brought into close contact with the cooling roll using an electrostatic application method. At this time, the surface temperature of the cooling roll is preferably about 10 ° C to 40 ° C.

<Polymer layer forming step>
After the polyester film substrate is prepared as described above, at least one side of the polyester film substrate has a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, an isocyanate group, an epoxy group, a silanol group, and an alkoxysilyl group. A polymer layer containing a binder having at least one functional group selected from is provided. As a method for forming a polymer layer in the present invention, there are a method for bonding a polymer sheet having easy adhesion to a polyester film and a method by coating, but the method by coating is simple and highly uniform thin film formation. Is preferable in that it is possible.

When the polymer layer is formed by coating, a known method such as a gravure coater or a bar coater can be used as the coating method. The solvent of the coating solution used for coating may be water or an organic solvent such as toluene or methyl ethyl ketone. A solvent may be used individually by 1 type and may be used in mixture of 2 or more types.
The coating step is preferably performed between extrusion and heat setting, and is preferably performed at least once after this. Thereby, the adhesiveness of a film base material and a polymer layer can be improved. This is considered to have an effect that the coating component and the chemical bond are expressed by radicals generated by the cleavage of molecules on the surface of the film substrate during stretching, and adhesion can be expressed more effectively.

  In addition, it is also preferable to perform a surface treatment on the polyester film substrate prior to the application of the polymer layer, and examples thereof include corona treatment, flame treatment, ultraviolet treatment, glow treatment, and atmospheric pressure plasma treatment.

<Drying process>
The polymer layer is cured by applying it in layers on a polyester film and drying prior to the stretching step. The polymer layer may have a two-layer structure. In this case, it is preferable that the second layer is applied and then dried and cured. The drying step is a step of supplying drying air to the polymer layer. In the drying step, it is preferable that the polymer layer is also dried and heat-treated.

<Extension process>
The polyester film formed by the film forming process or the laminated film obtained by laminating the polymer layer on the polyester film can be subjected to a stretching process in the stretching process.
In the step of stretching the polyester film, the polyester film is preferably stretched uniaxially or biaxially, and more preferably biaxially stretched. Stretching in the biaxial direction (biaxial stretching) includes stretching in the longitudinal direction (MD: Machine Direction) (hereinafter also referred to as “longitudinal stretching”) and stretching in the width direction (TD: Transverse Direction) (hereinafter referred to as “lateral stretching”). It is also preferred that The longitudinal stretching and lateral stretching may each be performed once, or may be performed a plurality of times, and may be simultaneously performed longitudinally and laterally.
Moreover, after extending | stretching a polyester film to MD direction, it is good also as laminating | stacking a polymer layer as mentioned above, and extending | stretching to TD direction after that, after laminating | stacking a polymer layer on a polyester film, it is biaxial direction. It is good also as extending | stretching.
The stretching treatment is preferably performed at a glass temperature (Tg) ° C. to (Tg + 60) ° C. of the film, more preferably Tg + 3 ° C. to Tg + 40 ° C., and further preferably Tg + 5 ° C. to Tg + 30 ° C.

A preferable draw ratio is 280% to 500%, more preferably 300% to 480%, and further preferably 320% to 460% on at least one side. In the case of biaxial stretching, the film may be stretched evenly in the vertical and horizontal directions, but it is more preferable to stretch one of the stretch ratios more than the other and unevenly stretch. Either vertical (MD) or horizontal (TD) may be increased. The draw ratio here is determined using the following equation.
Stretch ratio (%) = 100 × (length after stretching) / (length before stretching)

The biaxial stretching treatment is performed at, for example, (Tg ₁ ) ° C. to (Tg ₁ +60) ° C., which is the glass transition temperature of the film, once or twice in the longitudinal direction, so that the total magnification becomes 3 to 6 times. stretched, can then be applied _{(Tg 1) ℃ ~ (Tg} + 60) to the magnification in the width direction at ° C. is three to five times.

  The biaxial stretching process can be stretched in the longitudinal direction using two or more pairs of nip rolls whose peripheral speed on the outlet side is increased (longitudinal stretching), and both ends of the film are gripped by chucks and are orthogonally crossed (longitudinal direction). (Perpendicular direction) can be performed (lateral stretching).

  In the stretching step, the film can be heat-treated before or after the stretching treatment, preferably after the stretching treatment. By performing heat treatment, microcrystals can be generated, and mechanical properties and durability can be improved. The film may be subjected to heat treatment at about 180 ° C. to 210 ° C. (more preferably 185 ° C. to 210 ° C.) for 1 second to 60 seconds (more preferably 2 seconds to 30 seconds).

In the stretching step, a thermal relaxation treatment can be performed after the heat treatment. The thermal relaxation treatment is a treatment for shrinking the film by applying heat to the film for stress relaxation. The thermal relaxation treatment is preferably performed in both the MD and TD directions of the film. The various conditions in the thermal relaxation treatment are preferably a treatment at a temperature lower than the heat treatment temperature, and preferably 130 to 205 ° C. In the thermal relaxation treatment, the thermal shrinkage rate (150 ° C.) of the film is preferably 1 to 12% for both MD and TD, and more preferably 1 to 10%. For heat shrinkage (150 ° C), a sample with a measurement direction of 350 mm and a width of 50 mm was cut out, marked at 300 mm intervals near both ends in the longitudinal direction of the sample, and fixed at one end to an oven adjusted to a temperature of 150 ° C. The other end is left free for 30 minutes, and then the distance between the gauge points is measured at room temperature. This length is defined as L (mm), and the heat shrinkage rate is obtained by the following formula using the measured value. Can do.
150 ° C. heat shrinkage (%) = 100 × (300−L) / 300
Further, when the thermal contraction rate is positive, it indicates shrinkage, and negative indicates elongation.

  As described above, a laminated film in which the crying of the ketene compound is suppressed can be produced by the above-described method. As will be described later, the laminated film of the present invention can be suitably used not only as a protective sheet for a solar cell module (back sheet for a solar cell module) but also for other uses.

(Back sheet for solar cell module)
The back sheet for a solar cell module of the present invention includes the above-described laminated film. In the laminated film of the present invention, since the ketene compound produced in the polyester film is suppressed from crying on the surface of the polymer layer, even when used for a back sheet for a solar cell module, it is good as an EVA film. High adhesion can be maintained.

  In the back sheet for a solar cell module of the present invention, for example, the following functional layer may be applied to the laminated film after uniaxial stretching and / or biaxial stretching. For coating, a known coating technique such as a roll coating method, a knife edge coating method, a gravure coating method, or a curtain coating method can be used.

<Reflective layer (colored layer)>
The back sheet for a solar cell module may further have a reflective layer (colored layer) as a functional layer. The colored layer is a layer arranged in contact with the surface of the polyester film or through another layer, and can be constituted using a pigment or a binder.

  The first function of the colored layer is to increase the power generation efficiency of the solar cell module by reflecting the light that has reached the back sheet without being used for power generation in the solar cell out of the incident light and returning it to the solar cell. is there. The second function is to improve the decorativeness of the appearance when the solar cell module is viewed from the front side. In general, when a solar cell module is viewed from the front side, a back sheet can be seen around the solar cell, and the decorativeness can be improved by providing a colored layer on the back sheet.

  Examples of the pigment include inorganic pigments such as titanium oxide, barium sulfate, silicon oxide, aluminum oxide, magnesium oxide, calcium carbonate, kaolin, talc, ultramarine blue, bitumen, and carbon black, and organic pigments such as phthalocyanine blue and phthalocyanine green. It is done. Among these pigments, a white pigment is preferable from the viewpoint of constituting a colored layer as a reflective layer that reflects incident sunlight. As the white pigment, for example, titanium oxide, barium sulfate, silicon oxide, aluminum oxide, magnesium oxide, calcium carbonate, kaolin, talc and the like are preferable.

As a binder suitable for the colored layer, for example, polyester, polyurethane, acrylic resin, polyolefin, or the like can be used. From the viewpoint of durability, the binder is preferably an acrylic resin or a polyolefin. As the acrylic resin, a composite resin of acrylic and silicone is also preferable. Examples of preferred binders include the following.
Examples of polyolefins include Chemipearl S-120 and S-75N (both manufactured by Mitsui Chemicals). Examples of the acrylic resin include Julimer ET-410 and SEK-301 (both manufactured by Nippon Pure Chemical Industries, Ltd.). Examples of the composite resin of acrylic and silicone include Ceranate WSA1060, WSA1070 (both manufactured by DIC Corporation), H7620, H7630, H7650 (both manufactured by Asahi Kasei Chemicals Corporation) and the like.

  In addition to the binder and the pigment, a cross-linking agent, a surfactant, a filler, and the like may be further added to the colored layer in the present invention as necessary.

<Undercoat layer>
An undercoat layer can be provided in the laminated film of the present invention. For example, when a colored layer is provided, the undercoat layer may be provided between the colored layer and the polyester film. The undercoat layer can be formed using a binder, a crosslinking agent, a surfactant, and the like.

  Examples of the binder contained in the undercoat layer include polyester, polyurethane, acrylic resin, and polyolefin. In addition to the binder, an epoxy, isocyanate, melamine, carbodiimide, oxazoline, or other crosslinking agent, anionic or nonionic surfactant, silica or other filler may be added to the undercoat layer.

<Anti-fouling layer (fluorine resin layer / silicon resin layer)>
The polyester film of the present invention is preferably provided with at least one of a fluorine-based resin layer and a silicon-based (Si-based) resin layer as an antifouling layer. By providing the fluorine-based resin layer or the Si-based resin layer, it is possible to prevent contamination of the polyester surface and improve weather resistance. Specifically, it is preferable to have the fluororesin-based coating layer described in JP2007-35694A, JP2008-28294A, and WO2007 / 063698.
Moreover, it is also preferable to stick together fluorine resin films such as Tedlar (manufactured by DuPont).

[Solar cell module]
The solar cell module of the present invention includes the polyester film of the present invention or the back sheet for the solar cell module of the present invention.
The solar cell module of the present invention comprises a solar cell element that converts light energy of sunlight into electric energy, a transparent substrate on which sunlight is incident, and the polyester film (back sheet for solar cell) of the present invention described above. It is arranged and arranged between. A space between the substrate and the polyester film can be configured by sealing with a resin (so-called sealing material) such as an ethylene-vinyl acetate copolymer.

  The members other than the solar cell module, the solar cell, and the back sheet are described in detail in, for example, “Photovoltaic power generation system constituent material” (supervised by Eiichi Sugimoto, Kogyo Kenkyukai, published in 2008).

  The transparent substrate only needs to have a light-transmitting property through which sunlight can pass, and can be appropriately selected from base materials that transmit light. From the viewpoint of power generation efficiency, the higher the light transmittance, the better. For such a substrate, for example, a glass substrate, a transparent resin such as an acrylic resin, or the like can be suitably used.

  Examples of solar cell elements include silicon-based materials such as single crystal silicon, polycrystalline silicon, and amorphous silicon, and group III-V such as copper-indium-gallium-selenium, copper-indium-selenium, cadmium-tellurium, gallium-arsenide, and II. Various known solar cell elements such as a group VI compound semiconductor can be applied.

  The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

  The ketene imine compound represented by the general formula (1) of the present invention, which was a ketene imine compound having the following structure, was used as an end-capping agent in each Example.

  The above ketene imine compound was synthesized by the following method.

[Synthesis Example 1]
(Synthesis of ketene imine (1))
<Synthesis of ketimine body (1)>
After charging 91 g (0.50 mol) of benzophenone, 27 g (0.25 mol) of p-phenylenediamine, 112 g (1.0 mol) of DABCO, and 1.5 L of chlorobenzene into a three-necked flask, the mixture was stirred at 125 ° C. for 1 hour, and then titanium tetrachloride. 95 g (0.5 mol) was slowly added. After stirring for 4 hours, the precipitate was filtered and the filtrate was concentrated. The solid obtained by concentration was washed with methanol to obtain 86 g (0.2 mol) of a ketimine compound (1) as a yellow powder.

<Synthesis of Aziridine Form (1)>
Ketimine compound (1) 44 g (0.1 mol), triethylbenzylammonium chloride 2 g and chloroform 300 ml were charged into a three-necked flask, and 200 g of 50% aqueous sodium hydroxide solution at 60 ° C. was added all at once with stirring, and the internal temperature was 40- Stir at 50 ° C. for 1 hour. After adding 300 ml of pure water and 500 ml of chloroform to remove the aqueous layer, the solution was concentrated and washed with MEK to obtain 30 g (0.05 mol) of aziridine (1).

<Synthesis of ketene imine (1)>
Aziridine (1) 30 g (0.05 mol), sodium iodide 135 g, and acetone 700 ml were charged into a flask and refluxed for 2 hours. After cooling, it was added to 1.4 L of 4% aqueous sodium thiosulfate solution and stirred for 30 minutes. The precipitated solid was filtered and washed with methanol to obtain 23 g (0.05 mol) of a yellow solid.
¹ H-NMR (DMSO) δ (ppm); 7.2-7.6 (24H)

[Synthesis Example 2]
(Synthesis of ketene imine (2))
<Synthesis of Mesyl Form (2)>
100 g (0.96 mol) of neopentyl glycol, 242 g (2.11 mol) of methanesulfonyl chloride and 900 ml of ethyl acetate are charged into a three-necked flask, and 214 g (2.11 mol) of triethylamine is slowly added dropwise at 0 to 10 ° C. Stir for 1 hour. After adding 500 ml of pure water and removing the aqueous layer, it was dried over sodium sulfate. After filtering sodium sulfate, the filtrate was concentrated to obtain 234 g (0.90 mol) of mesyl form (2).

<Synthesis of benzophenone (2)>
A flask was charged with 147 g (0.744 mol) of 4-hydroxybenzophenone, 80.6 g (0.31 mol) of mesyl compound (2), 308 g (2.23 mol) of potassium carbonate, and 1.3 L of DMF, and stirred at 120 ° C. for 16 hours. . After the reaction, the reaction solution was cooled, the reaction solution was added to 10 L of pure water, stirred for 30 minutes, filtered under reduced pressure, and washed with methanol to obtain 90 g (0.194 mol) of a benzophenone compound (2).

<Synthesis of ketimine body (2)>
A benzophenone compound (2) 82 g (0.177 mol), aniline 49 g (0.53 mol), DABCO 119 g (1.06 mol), and chlorobenzene 3.0 L were charged into a three-necked flask and stirred at 125 ° C. for 1 hour, and then tetrachloride. 67 g (0.353 mol) of titanium was slowly added. After stirring for 4 hours, the precipitate was filtered and the filtrate was concentrated. The solid obtained by concentration was washed with methanol to obtain 103 g (0.17 mol) of a ketimine compound (2) as a yellow powder.

<Synthesis of Aziridine Form (2)>
Ketimine compound (2) 88 g (0.143 mol), triethylbenzylammonium chloride 4.0 g, chloroform 600 ml were charged into a three-necked flask, and with stirring, 400 g of 50% aqueous sodium hydroxide solution 400 g was added all at once. It stirred at 40-50 degreeC for 1 hour. After adding 800 ml of pure water and 1200 ml of chloroform to remove the aqueous layer, the solution was concentrated to obtain 111 g (0.14 mol) of aziridine (2).

<Synthesis of ketene imine (2)>
Aziridine (2) 111 g (0.14 mol), sodium iodide 428 g, and acetone 2.0 L were charged into a flask and refluxed for 2 hours. After cooling, it was added to 4.2 L of 4% aqueous sodium thiosulfate solution and stirred for 30 minutes. The precipitated solid was filtered and purified by column to obtain 63.8 g (0.1 mol) of ketene imine (2).
¹ H-NMR (DMSO) δ (ppm); 1.1 (6H), 3.85 (4H), 7.0-7.6 (28H)

[Synthesis Example 3]
(Synthesis of ketene imine (3))
<Synthesis of mesyl body (3)>
Trimethylolpropane 100 g (0.75 mol), methanesulfonyl chloride 282 g (2.46 mol) and ethyl acetate 900 ml were charged into a three-necked flask, and 249 g (2.46 mol) of triethylamine was slowly added dropwise at 0-10 ° C. at room temperature. Stir for 1 hour. After adding 500 ml of pure water and removing the aqueous layer, it was dried over sodium sulfate. After filtering sodium sulfate, the filtrate was concentrated to obtain 2002 g (0.55 mol) of mesyl form (3).

<Synthesis of benzophenone (3)>
151 g (0.76 mol) of 4-hydroxybenzophenone, 77 g (0.21 mol) of mesyl compound (3), 315 g (2.28 mol) of potassium carbonate and 1.3 L of DMF were charged into a flask and stirred at 120 ° C. for 16 hours. After the reaction, the reaction solution was cooled, the reaction solution was added to 10 L of pure water, stirred for 30 minutes, filtered under reduced pressure, and washed with methanol to obtain 110 g (0.163 mol) of a benzophenone compound (3).

<Synthesis of ketimine body (3)>
Benzophenone compound (3) 100 g (0.148 mol), aniline 62 g (0.67 mol), DABCO 150 g (1.34 mol) and chlorobenzene 3.8 L were charged into a three-necked flask and stirred at 125 ° C. for 1 hour, followed by tetrachloride. 84 g (0.453 mol) of titanium was slowly added. After stirring for 4 hours, the precipitate was filtered and the filtrate was concentrated. The solid obtained by concentration was washed with methanol to obtain 126 g (0.14 mol) of a ketimine compound (3) as a yellow powder.

<Synthesis of Aziridine Form (3)>
Ketimine compound (2) 88 g (0.143 mol), triethylbenzylammonium chloride 4.0 g, chloroform 600 ml were charged into a three-necked flask, and with stirring, 400 g of 50% aqueous sodium hydroxide solution 400 g was added all at once. It stirred at 40-50 degreeC for 1 hour. After adding 800 ml of pure water and 1200 ml of chloroform to remove the aqueous layer, the solution was concentrated to obtain 111 g (0.14 mol) of aziridine (2).

<Synthesis of ketene imine (2)>
Aziridine (2) 111 g (0.14 mol), sodium iodide 428 g, and acetone 2.0 L were charged into a flask and refluxed for 2 hours. After cooling, it was added to 4.2 L of 4% aqueous sodium thiosulfate solution and stirred for 30 minutes. The precipitated solid was filtered and purified by column to obtain 63.8 g (0.1 mol) of ketene imine (2).
¹ H-NMR (DMSO) δ (ppm); 1.10 (3H), 2.90 (2H), 3.85 (6H), 7.0-7.6 (42H)

[Synthesis Example 4]
(Synthesis of ketene imine (4))
<Synthesis of benzophenone (4)>
A flask was charged with 335 g (1.69 mol) of 4-hydroxybenzophenone, 135 g (0.35 mol) of tetrabromopentaerythritol, 691 g (5.0 mol) of potassium carbonate, and 3.0 L of DMF, and stirred at 120 ° C. for 6 hours. After the reaction, the reaction solution was cooled, the reaction solution was added to 10 L of pure water, stirred for 30 minutes, and then filtered under reduced pressure to obtain 300 g (1.69 mol) of a benzophenone compound (4).

<Synthesis of ketimine body (4)>
Benzophenone compound (4) 109 g (0.127 mol), aniline 70.8 g (0.762 mol), DABCO 229.6 g (1.546 mol), and chlorobenzene 3.0 L were charged into a three-necked flask and stirred at 125 ° C. for 1 hour. Thereafter, 99 g (0.51 mol) of titanium tetrachloride was slowly added. After stirring for 4 hours, the precipitate was filtered and the filtrate was concentrated. The solid obtained by concentration was washed with methanol to obtain 135 g (0.117 mol) of a ketimine compound (4) as a yellow powder.

<Synthesis of Aziridine Form (4)>
Ketimine body (4) 43 g (0.0375 mol), triethylbenzylammonium chloride 1.5 g and chloroform 230 ml were charged into a three-necked flask, and with stirring, 150 g of 50% aqueous sodium hydroxide solution at 60 ° C. was added all at once. It stirred at 40-50 degreeC for 1 hour. After adding 300 ml of pure water and 450 ml of chloroform to remove the aqueous layer, the solution was concentrated to obtain 41 g (0.0276 mol) of the aziridine compound (4).

<Synthesis of ketene imine (4)>
The flask was charged with 41 g (0.0276 mol) of aziridine (4), 170 g of sodium iodide and 900 ml of acetone, and refluxed for 2 hours. After cooling, it was added to 1.7 L of 4% sodium thiosulfate aqueous solution and stirred for 30 minutes. The precipitated solid was filtered and purified by column to obtain 24 g (0.02 mol) of ketene imine (4).
¹ H-NMR (DMSO) δ (ppm); 4.34 (8H), 7.0-7.5 (56H)

[Synthesis Example 5]
(Synthesis of ketene imine (5))
It synthesize | combined like the ketene imine (4) except having changed aniline into o-toluidine at the time of the synthesis | combination of a ketimine body (5).

[Synthesis Example 6]
(Synthesis of ketene imine (6))
<Synthesis of Benzophenone (6)>
250 g (1.47 mol) of diphenyl ether and 3.0 L of chlorobenzene were charged into a three-necked flask, and 420 g (3.16 mol) of aluminum chloride and 444 g (3.16 mol) of benzoyl chloride were added while cooling to 0 ° C. and stirring. After stirring for 2 hours, 2.0 L of ethyl acetate and 15 L of 1N HCl water were added, filtered, and washed with 1 L of pure water, 1 L of ethyl acetate, and 1 L of methanol to obtain 495 g of a benzophenone compound (6).

<Synthesis of ketimine body (6)>
A benzophenone compound (6) (134 g, 0.354 mol), aniline (99 g, 1.06 mol), DABCO (238 g, 2.12 mol), and chlorobenzene (3.0 L) were charged into a three-necked flask and stirred at 125 ° C. for 1 hour, followed by tetrachloride. 13.4 g (0.7 mol) of titanium was slowly added. After stirring for 4 hours, the precipitate was filtered and the filtrate was concentrated. The solid obtained by concentration was washed with methanol to obtain 184.9 g (0.35 mol) of a ketimine compound (6) as a yellow powder.

<Synthesis of Aziridine Form (6)>
120 g (0.227 mol) of ketimine body (6), 2.9 g of triethylbenzylammonium chloride, and 1.2 L of chloroform were charged into a three-necked flask, and 720 g of a 50% aqueous sodium hydroxide solution at 60 ° C. was added all at once while stirring. The temperature was stirred at 40-50 ° C. for 1 hour. After adding 1.4 ml of pure water and 1.8 L of chloroform to remove the aqueous layer, the solution was concentrated to obtain 152.3 g (0.227 mol) of an aziridine compound (6).

<Synthesis of ketene imine (6)>
The flask was charged with 60 g (0.087 mol) of aziridine (6), 20 g of zinc powder and 800 ml of THF. While cooling to 0 ° C. and stirring, 0.9 ml of concentrated hydrochloric acid was added in three portions. After stirring for 30 minutes, the reaction solution was added to 4 L of methanol, and the precipitated solid was filtered to obtain 44 g (0.08 mol) of ketene imine (6).
¹ H-NMR (DMSO) δ (ppm); 7.12 (4H), 7.25-7.6 (24H)

[Synthesis Example 7]
(Synthesis of ketene imine (7))
It was synthesized in the same manner as ketene imine (6) except that aniline was changed to 2,6-dimethylaniline at the time of synthesis of ketimine body (7).

  The laminated film of Examples 1-17 and Comparative Examples 1-3 was produced by the following method. Table 1 shows the types of ketene imine compounds or binders.

[Production of polyester film]
-Process (A)-
4.7 tons of high-purity terephthalic acid and 1.8 tons of ethylene glycol were mixed for 90 minutes to form a slurry, which was continuously supplied to the first esterification reactor at a flow rate of 3800 kg / h. Next, an ethylene glycol solution of a citric acid chelate titanium complex ("VERTEC AC-420", manufactured by Johnson Matthey) in which citric acid is coordinated to Ti metal is continuously supplied to the first esterification reaction tank. While stirring at an internal temperature of 250 ° C., the reaction was carried out with an average residence time of about 4.4 hours to obtain an oligomer. At this time, the citric acid chelate titanium complex was continuously added so that the amount of Ti added was 9 ppm in terms of element. The acid value of the obtained oligomer was 500 eq / ton.

The obtained oligomer was transferred to a second esterification reaction tank and reacted by stirring at a reaction tank temperature of 250 ° C. and an average residence time of 1.2 hours to obtain an oligomer having an acid value of 180 eq / ton. The inside of the second esterification reaction tank is divided into three zones from the first zone to the third zone. From the second zone, an ethylene glycol solution of magnesium acetate is added, and the amount of Mg added is 75 ppm in terms of element. Then, from the third zone, an ethylene glycol solution of trimethyl phosphate was continuously supplied so that the addition amount of P was 65 ppm in terms of element. The ethylene glycol solution of trimethyl phosphate was prepared by adding a 25 ° C. trimethyl phosphate solution to a 25 ° C. ethylene glycol solution and stirring at 25 ° C. for 2 hours (phosphorus compound content in the solution: 3 .8% by mass).
As a result, an esterification reaction product was obtained.

-Process (B)-
The esterification reaction product obtained in the step (A) was continuously supplied to the first polycondensation reaction tank. Next, polycondensation (ester exchange reaction) is carried out with an average residence time of about 1.8 hours while stirring the esterification reaction product at a reaction temperature of 270 ° C. and a reaction tank pressure of 20 torr (2.67 × 10 ⁻³ MPa). It was.

Next, the obtained reaction product was transferred from the first polycondensation reaction tank to the second double condensation reaction tank. Thereafter, the reaction product was stirred in the second double condensation reaction tank at a reaction tank temperature of 276 ° C. and a reaction tank pressure of 5 torr (6.67 × 10 ⁻⁴ MPa), and the residence time was about 1.2 hours. (Transesterification reaction).

Subsequently, the reaction product obtained by the transesterification reaction is further transferred from the second double condensation reaction tank to the third triple condensation reaction tank. In this reaction tank, the reaction tank internal temperature is 276 ° C. and the reaction tank internal pressure is 1. While stirring at 5 torr (2.0 × 10 ⁻⁴ MPa), the reaction (transesterification reaction) was performed under the condition of a residence time of 1.5 hours. Carboxylic acid value: 22 eq / ton, IV (intrinsic viscosity): 0.65 dl / G reaction product (polyethylene terephthalate (PET)) was obtained.

  Furthermore, the obtained PET was subjected to a heat treatment (solid phase polymerization) at 205 ° C. for 24 hours under a reduced pressure of 50 Pa using a rotary vacuum polymerization apparatus. Thereafter, nitrogen gas at 25 ° C. was allowed to flow into the vacuum polymerization apparatus, and the pellet was cooled to 25 ° C. to obtain PET having a carboxylic acid value of 15 eq / ton and IV of 0.78 dl / g.

<Evaluation of polyester resin>
Using the obtained polyester resin, the carboxylic acid value was measured by the following method.
(Acid value of resin (terminal COOH group amount))
About the obtained polyester resin, H.M. A. Pohl, Anal. Chem. 26 (1954) 2145, the amount of terminal COOH groups was measured by a titration method. Specifically, the polyester resin was dissolved in benzyl alcohol at 205 ° C., a phenol red indicator was added, and titration was performed with a water / methanol / benzyl alcohol solution of sodium hydroxide.

-Extrusion molding (synthesis process, film formation process)-
The obtained polyester resin is charged into a hopper of a biaxial kneading and extruding machine having a diameter of 50 mm with a main feeder, a ketene imine compound is charged into a sub-feeder, and the contents are measured so that the respective contents are as shown in Table 1. The resin was melted and extruded so that the maximum resin temperature reached 300 ° C. The extruded melt (melt) was passed through a gear pump and a filter (pore diameter: 20 μm), and then extruded from a die to a 20 ° C. cooling roll to obtain an amorphous sheet. The extruded melt was brought into close contact with the cooling roll using an electrostatic application method.

-Stretching (biaxial stretching process)-
As described above, the polymer layer laminated film was sequentially biaxially stretched by the following method to obtain a polyester film having a thickness of 250 μm.
<Stretching method>
(A) Longitudinal stretching The unstretched film was passed between two pairs of nip rolls having different peripheral speeds and stretched in the longitudinal direction (conveying direction). The preheating temperature was 90 ° C., the stretching temperature was 90 ° C., the stretching ratio was 3.5 times, and the stretching speed was 3000% / second.
(B) Transverse stretching The longitudinally stretched film was stretched laterally under the following conditions using a tenter.
<Conditions>
-Preheating temperature: 100 ° C
-Stretching temperature: 110 ° C
-Stretching ratio: 4.2 times-Stretching speed: 70% / second

-Heat fixation / thermal relaxation-
Then, the stretched film after finishing longitudinal stretching and lateral stretching was heat-set under the following conditions. Further, after heat setting, the tenter width was reduced and heat relaxation was performed under the following conditions.
<Heat setting conditions>
・ Heat setting temperature: 198 ℃
・ Heat setting time: 2 seconds <thermal relaxation conditions>
-Thermal relaxation temperature: 195 ° C
-Thermal relaxation rate: 5%

(Examples 1 to 17)
Then, in Examples 1-17, the polymer layer coating liquid which mixed the binder of Table 1 was apply | coated using the bar-coater.

The composition of the coating solution for forming a polymer layer adjacent to the polyester support was as follows.
・ Binder: 400.0 parts by mass Nonionic surfactant: 15.0 parts by mass (Naroacty CL95, manufactured by Sanyo Chemical Industries, Ltd., solid content concentration: 1% by mass)
-Oxazoline-based crosslinking agent: 180.8 parts by mass (Epocross WS-700, manufactured by Nippon Shokubai Co., Ltd., solid content concentration: 25% by mass)
-Distilled water ... 30.0 mass parts The coating liquid for polymer layer formation of the said composition was apply | coated to the corona treatment surface of the polyester support body. At that time, the coating amount of the coating liquid for forming the polymer layer was adjusted so that the addition rate of the binder described in Table 1 was obtained. Then, it dried at 175 degreeC for 2 minute (s), and the polymer layer adjacent to a polyester support body was formed.

The following were used as the binder. In Examples 1-17, the binder of Table 1 was selected and used as a binder of the coating liquid for polymer layer formation.
・ Arrow base SE-1013N Unitika Co., Ltd.
・ Ceranate WSA1070 (silicone / acrylic composite polymer) DIC Corporation, solid content concentration 38% by mass
・ Nipol SX1105 Made by Nippon Zeon ・ PVA105 (polyvinyl alcohol) 50% aqueous solution Kuraray Co., Ltd. ・ PMMA ALDRICH

(Comparative Example 1)
In Comparative Example 1, a coating solution for forming a polymer layer having the following composition was prepared.
・ PMMA (manufactured by ALDRICH)… 100.0 parts by mass • Distilled water… 900.0 parts by mass

The polymer layer forming coating solution is applied to the corona-treated surface of the polyester support so that the binder coating amount is 5.1 g / m ² (283 parts by mass with respect to 100 parts by mass of the ketene imine compound), and at 175 ° C. for 2 minutes. Dried to form a polymer layer adjacent to a 8 μm dry thickness polyester support.

(Comparative Examples 2 and 3)
Comparative Examples 2 and 3 did not form a polymer layer on the polyester support.

-Winding-
After heat setting and heat relaxation, both ends of the laminated film were trimmed by 10 cm. Then, after extruding (knurling) with a width of 10 mm at both ends, it was wound up with a tension of 25 kg / m. The width was 1.5 m and the winding length was 2000 m.
The polyester film of Examples 1-17 and Comparative Examples 1-3 was produced as mentioned above.

  The laminated films of Examples 1 to 17 and Comparative Examples 1 to 3 were evaluated by the following methods, and the results are shown in Table 1.

-Evaluation of the performance of laminated films-
(Hydrolysis resistance (PCT test))
The hydrolysis resistance was evaluated based on the half life of elongation at break. The breaking elongation retention half-life was determined by subjecting the laminated films obtained in Examples and Comparative Examples to storage treatment (heating treatment) under the conditions of 120 ° C. and relative humidity of 100%. The breaking elongation (%) shown was evaluated by measuring the storage time at which the breaking elongation (%) exhibited by the laminated film before storage was 50%. The obtained results are shown in Table 1 below.
5: Break elongation half-life of 200 hours or more 4: Break elongation half-life of 170 hours to less than 200 hours 3: Break elongation half-life of 140 hours to less than 170 hours 2: Break elongation half-life of 110 hours or more Less than 140 hours 1: Break elongation half-life is less than 110 hours The longer the break elongation retention half-life, the better the hydrolysis resistance of the laminated film. That is, the laminated film of the present invention preferably has a breaking elongation half-life of 130 hours or more and more preferably 160 hours or more before and after being subjected to a storage treatment at 120 ° C. and a relative humidity of 100%.

(Adhesion)
Two sample films (MD 20 cm, TD 3 cm) were prepared, and an EVA film having a thickness of 2 mm, a width of 3 cm, and a length of 10 cm was sandwiched on both sides of the easy adhesion layer. At this time, a polyester film was prepared, and an EVA film was placed on one end of both films. That is, the polyester film protrudes from the EVA film by 10 cm on the same side.
The EVA film was heat-treated at 140 ° C. for 5 minutes while applying a pressure of 1 atm of both polyester films, and then allowed to stand at room temperature for one day. Then, the polyester film at both ends was put on a tensile tester, both ends were pulled in the direction of 180 degrees at 30 mm / min, the maximum stress was measured, and it was corrected per unit width (divided by 30 because the sample was 3 cm, to the force per 1 mm Conversion is shown in Table 1.
5: Peeling force 14 N / mm or more 4: Peeling force 10 to 14 N / mm or more 3: Peeling force 8 to 10 N / mm or more 2: Peeling force 4 to 8 N / mm or more 1: Peeling force 4 N / mm or less

  Since the laminated film of Examples 1-17 is comprised from the polymer film containing the polyester film containing the ketene imine compound represented by General formula (1) mentioned above, and the binder which has a specific functional group, hydrolysis resistance It can be seen that the ketene compound is suppressed from crying. Thereby, the adhesiveness with the EVA film is good. In particular, Examples 2 to 4 and 6 to 16 have extremely excellent hydrolysis resistance and an effect of suppressing crying out, and are understood to be preferable examples.

On the other hand, Comparative Example 1 does not contain a binder having a specific functional group. Since the polyester film contains the ketene imine compound represented by the general formula (1) described above, the polyester film exhibits excellent hydrolysis resistance, but does not contain a binder having a specific functional group. Unloading is not suppressed. For this reason, adhesiveness with an EVA film is remarkably bad.
In Comparative Example 2, the polyester film contains no ketene imine compound, and no polymer layer is formed. In Comparative Example 2, since the polyester film does not contain a ketene imine compound, the hydrolysis resistance is extremely poor. Moreover, since the polymer layer is not formed, the adhesiveness of the polyester film and the EVA film is lowered.
Since the comparative example 3 contains the ketene imine compound in the polyester film, it shows hydrolysis resistance. However, since the polymer layer is not formed, the adhesion between the polyester film and the EVA film is lowered.

  From the above, it was found that in the laminated film of the present invention, in addition to suppressing hydrolysis of the polyester film, crying of the ketene compound produced in the polyester film can be suppressed.

  According to the present invention, a ketene compound starts to cry on the surface of a polymer layer by laminating a polymer layer containing a binder having a specific functional group on a polyester film containing a ketene imine compound having a specific structure. This can be suppressed. Thereby, since the solar cell module backsheet excellent in adhesiveness with an EVA film can be obtained, industrial applicability is high.

2 Polyester film 3 Polymer layer 5 EVA film (attachment)
10 Laminated film

Claims (10)

A laminated film comprising a polyester film and a polymer layer laminated adjacent to at least one surface of the polyester film,
The polyester film includes polyester and a ketene imine compound represented by the following general formula (1),
The polymer layer includes a binder having at least one functional group selected from a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, an isocyanate group, an epoxy group, a silanol group, and an alkoxysilyl group. .

(In general formula (1), R ₁ and R ₂ each independently represents an aryl group, an aryloxy group, an arylaminocarbonyl group, or an aryloxycarbonyl group, and R ₃ represents an alkyl group or an aryl group.) The laminated film according to claim 1, wherein the ketene imine compound is represented by the following general formula (2).

(In the general formula (2), R _{11 to} R ₂₀ each independently represents a hydrogen atom, an alkyl group, an aryl group or an alkoxy group. R _{11 to} R ₂₀ may combine with each other to form a ring. R ₃ represents an alkyl group or an aryl group.)   The laminated film according to claim 1 or 2, wherein the polymer layer includes a binder having at least one functional group selected from a carboxyl group, an epoxy group, and an alkoxysilyl group.   The addition rate of the said ketene imine compound is 0.1-2 mass% with respect to the total amount of the said polyester, The laminated | multilayer film of any one of Claims 1-3 characterized by the above-mentioned.   100 parts by mass of the ketene imine compound has at least one functional group selected from the carboxyl group, hydroxyl group, amino group, sulfonic acid group, isocyanate group, epoxy group, silanol group, and alkoxysilyl group. The laminated film according to any one of claims 1 to 4, comprising 0.1 to 1000 parts by mass of a binder.   The laminated film according to any one of claims 1 to 5, wherein the laminated film is biaxially stretched.   The back sheet | seat for solar cell modules using the laminated | multilayer film of any one of Claims 1-6.   The solar cell module using the solar cell module backsheet of Claim 7. A film forming step for obtaining a polyester film by pouring a melt obtained by melting a mixture containing polyester and a ketene imine compound represented by the following general formula (1) to be cooled and solidified;
A stretching step of stretching the polyester film in a biaxial direction;
At least one selected from a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, an isocyanate group, an epoxy group, a silanol group, and an alkoxysilyl group is formed on at least one surface of the polyester film stretched in the biaxial direction. And a step of forming a polymer layer containing a binder having a kind of functional group.

(In general formula (1), R ₁ and R ₂ each independently represents an aryl group, an aryloxy group, an arylaminocarbonyl group, or an aryloxycarbonyl group, and R ₃ represents an alkyl group or an aryl group.) A film forming step for obtaining a polyester film by pouring a melt obtained by melting a mixture containing polyester and a ketene imine compound represented by the following general formula (1) to be cooled and solidified;
A stretching step of stretching the polyester film in the MD direction;
At least one selected from a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, an isocyanate group, an epoxy group, a silanol group, and an alkoxysilyl group on at least one surface of the polyester film stretched in the MD direction. Forming a polymer layer containing a binder having a functional group of:
And a stretching step of stretching the polyester film on which the polymer layer is laminated in the TD direction.

(In general formula (1), R ₁ and R ₂ each independently represents an aryl group, an aryloxy group, an arylaminocarbonyl group, or an aryloxycarbonyl group, and R ₃ represents an alkyl group or an aryl group.)

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