JPH10256580A - Material for solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sufficiently adhesive material for solar cells comprising a polymer containing fluorine and a solar cell module of excellent transparency, dustproof and weather resistance using the material for solar cells. SOLUTION: A material for solar cells comprises an ethylene polymer containing functional group and fluorine made by the copolymerization of (a) 0.05 to 30 mol% of at least one kind of fluoroethylene monomer containing at least one kind of functional group selected among a group of hydroxyl group, carboxyl group, carboxyl acid salt, carboxylester group and epoxy group, and (b) 70 to 99.95 mol% of at least one kind of ethylene monomer containing fluorine without the above functional group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell material having excellent adhesion to other materials and, as a result, improved transparency, and a solar cell module using the same.

[0002]

2. Description of the Related Art Solar cells have already been put into practical use as a clean energy source instead of petroleum energy.
Currently, the important themes are the improvement of the photoelectric exchange efficiency of the photovoltaic element itself, the improvement of the photoelectric exchange efficiency as a solar cell module, and the improvement of construction and application to the site. .

As shown in FIG. 1 which is a schematic sectional view of the basic structure of a solar cell module, a photovoltaic element 2 (terminals and the like are not shown) is provided on an insulating substrate 1 or a film. A transparent filler layer 3 as a protective layer of the device,
Further, a surface film 4 is provided as an outermost layer (a layer exposed on the surface). The light passes through the surface film 4 and the transparent filler layer 3 which are the coating layers of the photovoltaic element 2, reaches the photovoltaic element 2, and is converted into electric energy.

[0004] Therefore, the surface film 4 and the transparent filler layer 3, which are the coating layers, must be excellent in light transmittance, and since they are exposed to sunlight outdoors for a long period of time, they suffer from light degradation. It must be excellent in weather resistance and heat resistance. In addition, since the surface film 4 is always in contact with the outside world, it is required that the contaminants hardly adhere (non-adhesive) and the contaminants are easily removed (antifouling properties). On the other hand, the transparent filler layer 3 is required to have impact resistance in order to buffer external impact and protect the photovoltaic element 2.

In consideration of such demands, tetrafluoroethylene-ethylene copolymer (ETFE), polychlorotrifluoroethylene (PC
TFE), tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA), polyvinyl fluoride (PVd), polyvinylidene fluoride (PVd
F), a fluoropolymer such as a tetrafluoroethylene-hexafluoropropylene copolymer (FEP) or a polyvinylidene fluoride copolymer, and an ethylene-vinyl acetate copolymer (EVA) and a butyral resin for the filler layer 3 A solar cell module using is described in JP-A-7-297439.

Japanese Unexamined Patent Publication (Kokai) No. 7-302925 discloses that the above-mentioned fluorine-containing polymer is used as a surface film material, and that a fluorine-containing rubber such as a vinylidene fluoride-hexafluoropropylene copolymer is used as a material for a transparent filler layer. It has been proposed to use

However, the fluorine-containing polymer has essentially poor adhesion to other materials, and as a result, the surface film and the filler layer are displaced and peeled off.

In the solar cell module described in the above publication, a silane coupling agent, an organic titanate compound, or the like is added to the filler layer, or the surface of the surface film is subjected to a corona discharge treatment or a plasma treatment to improve the adhesiveness. Trying to improve.

However, the addition of a silane coupling agent or the like not only has an insufficient effect of improving the adhesiveness but also degrades the silane coupling agent at the time of bonding at a high temperature to cause coloration or foaming, thereby reducing light transmittance. Lower it. In a method such as a corona discharge treatment of a surface film, the productivity of the surface treatment step itself is poor, and the cost is high. Also, in the first place, the corona discharge treatment alone is insufficient in the adhesiveness to the substrate,
Further, it is necessary to graft a vinyl acetate monomer or the like on the surface, and there is a problem that productivity is poor and cost is disadvantageous. In addition, surface treatment such as sodium etching also causes coloring and lowers light transmittance.

[0010] In addition, as a method for improving the adhesiveness of a fluorine-containing polymer, studies have been made on adhesion by an adhesive composition using a fluorine-containing polymer having a functional group.

For example, a hydrocarbon monomer having a carboxyl group, a carboxylic anhydride residue, an epoxy group or a hydrolyzable silyl group typified by maleic anhydride or vinyltrimethoxysilane is grafted onto a fluoropolymer. Reports of using a polymerized fluoropolymer as an adhesive (for example, JP-A-7-18035, JP-A-7-25952)
JP-A-7-25954, JP-A-7-173230
JP-A-7-173446, JP-A-7-17344
No. 7 publications) and adhesion of a fluorine-containing copolymer obtained by copolymerizing a hydrocarbon monomer containing a functional group such as hydroxylalkyl vinyl ether with tetrafluoroethylene or chlorotrifluoroethylene, and an isocyanate-based curing agent There has been a report (for example, Japanese Patent Application Laid-Open No. Hei 7-228848) in which a conductive composition is cured and used as an adhesive between polyvinyl chloride and ETFE subjected to corona discharge treatment.

An adhesive composition using a fluororesin obtained by graft-polymerizing or copolymerizing a hydrocarbon-based functional group monomer has insufficient heat resistance, and has a high temperature in the process of producing a composite with a fluororesin film. When the temperature is increased by sunlight or when the temperature is increased by processing, the composition may decompose or foam to lower the adhesive strength, peel off, or discolor. In the adhesive composition described in JP-A-7-228848, the fluororesin film requires corona discharge treatment.

[0013]

SUMMARY OF THE INVENTION In view of the above facts, an object of the present invention is to provide a material for a solar cell comprising a fluoropolymer having excellent adhesiveness without requiring a complicated process. It is in.

Another object of the present invention is to provide a solar cell module having excellent transparency, antifouling property and weather resistance by using the solar cell material.

[0015]

SUMMARY OF THE INVENTION The present invention provides (a) a functional group containing at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, a carboxylate, a carboxyester group and an epoxy group. 0.05 to 30 at least one kind of fluorine-containing ethylenic monomer
(B) at least one monomer of the above-mentioned fluorine-containing ethylenic monomer having no functional group and 70 to 99.95.
The present invention relates to a material for a solar cell, comprising a functional group-containing fluorine-containing ethylenic polymer obtained by copolymerizing the polymerizable compound with a mole%.

In this case, the functional group-containing fluorine-containing ethylenic monomer (a) is represented by the formula (1): CX ₂ = CX ¹ -R _f -Y (1) (where Y is -CH ₂ OH) , -COOH, a carboxylate salt, a carboxyester group or an epoxy group, X and X ¹ are the same or different and are a hydrogen atom or a fluorine atom,
R _f is a divalent fluorinated alkylene group having 1 to 40 carbon atoms,
A fluorine-containing oxyalkylene group having 1 to 40 carbon atoms, a fluorine-containing alkylene group containing an ether group having 1 to 40 carbon atoms or a fluorine-containing oxyalkylene group containing an ether bond having 1 to 40 carbon atoms) Preferably, it is a fluorine-containing ethylenic monomer containing various functional groups.

In addition, the fluorine-containing ethylenic monomer (b) having no functional group is preferably tetrafluoroethylene 85-85.
99.7 mol% and formula (2): CF ₂ ＝ CF—R _f ¹ (2) (where R _f ¹ is CF ₃ or OR _f ² (R _f ² is carbon number 1 to
5 perfluoroalkyl group)
It is preferably a mixed monomer of up to 15 mol%.

With respect to the fluorine-containing ethylenic monomer (b) having no functional group, tetrafluoroethylene 40
It is preferably a mixed monomer of about 80 mol%, 20 to 60 mol% of ethylene and 0 to 15 mol% of other copolymerizable monomers.

The fluorine-containing ethylenic monomer (b) having no functional group is preferably vinylidene fluoride.

When the content of the functional group-containing fluorine-containing ethylenic monomer (a) is 0.01 to 30% by mole of the total amount of the monomer, the amount of the fluorine-containing ethylenic monomer having no functional group can be reduced. The compound (b) is a mixed monomer of 70 to 99 mol% of vinylidene fluoride and 1 to 30 mol% of tetrafluoroethylene, based on the total amount of the monomers except the monomer (a); 50-99 mol%, tetrafluoroethylene 0-30 mol%, chlorotrifluoroethylene 1-20
Mol% of mixed monomer, or vinylidene fluoride 60 to 9
It is preferably a mixed monomer of 9 mol%, 0 to 30 mol% of tetrafluoroethylene and 1 to 10 mol% of hexafluoropropylene.

The fluorine-containing ethylenic monomer (b) having no functional group is composed of 40 to 90 mol% of vinylidene fluoride, 0 to 30 mol% of tetrafluoroethylene and 10 to 50 mol% of hexafluoropropene. Mixed monomer with tetrafluoroethylene 40 to 70 mol%, propylene 3
0 to 60 mol%, a mixed monomer with 0 to 20 mol% of other monomers copolymerizable therewith, or a mixture of 40 to 85 mol% of tetrafluoroethylene and 15 to 60 mol% of perfluorovinyl ethers It is preferably a monomer.

The present invention also relates to a solar cell material comprising the functional group-containing fluorine-containing ethylenic polymer in the form of a film.

The present invention also relates to a solar cell surface material using the solar cell material.

The present invention also relates to a surface film using the solar cell material.

The present invention also relates to a material for a transparent filler layer for a solar cell using the material for a solar cell.

The present invention also relates to a sealing material for a solar cell using the above solar cell material.

The present invention also relates to a solar cell module in which at least one of one or more coating materials provided on the light incident side of the photovoltaic element is formed of the above-mentioned solar cell material.

In this case, it is preferable that the coating material includes a surface film and a transparent filler layer, and at least one of the surface film and the transparent filler layer is formed of the solar cell material.

Further, it is preferable that the surface film is formed of the solar cell material.

Preferably, the transparent filler layer is formed of a transparent organic resin.

Preferably, the organic resin is the material for a solar cell.

Preferably, the organic resin is an ethylene-vinyl acetate copolymer.

Preferably, the transparent filler layer contains a glass-based material.

Preferably, the photovoltaic element comprises a semiconductor photoactive layer or a compound semiconductor layer.

Preferably, the semiconductor photoactive layer is a silicon-based semiconductor layer.

It is preferable that the silicon-based semiconductor layer is an amorphous silicon semiconductor layer, a single-crystal amorphous silicon semiconductor layer, or a polycrystalline amorphous silicon semiconductor layer.

[0037] The present invention also relates to a building material in which the solar cell module is arranged so as to be exposed to sunlight.

[0038] The present invention also relates to a roofing material, wherein the solar cell module is arranged to be exposed to sunlight.

Further, the present invention relates to a soundproof wall in which the solar cell module is disposed so as to be exposed to sunlight.

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION The solar cell material of the present invention can be widely applied to members constituting a solar cell, but is particularly useful as a material for a member requiring adhesiveness and weather resistance. From this viewpoint, it can be used as a surface material such as a surface film and its covering material, a material for a transparent filler layer, a sealing material, and also as an adhesive for bonding between members.

Hereinafter, first, the functional group-containing fluorine-containing ethylenic polymer constituting the material of the present invention will be described, and then each material and a solar cell module using the material will be described.

The functional group-containing fluorine-containing ethylenic polymer for use in the solar cell material of the present invention comprises (a) at least one selected from the group consisting of a hydroxyl group, a carboxyl group, a carboxylate, a carboxylester group and an epoxy group. 0.05 to 30 mol% of at least one kind of the functional group-containing fluorine-containing ethylenic monomer having one kind of functional group and (b) the fluorine-containing ethylenic monomer having no functional group It is a fluorine-containing ethylenic polymer having a functional group obtained by copolymerizing at least one kind of a monomer with 70 to 99.95 mol%.

The functional group-containing fluorine-containing polymer used to obtain the material of the present invention is obtained by using the above-mentioned functional group-containing fluorine-containing ethylenic monomer (a), It is important to copolymerize with the ethylenic monomer (b) to introduce a functional group into the fluorinated polymer, thereby giving excellent adhesion. In other words, even a functional group-containing fluoropolymer has excellent heat resistance as compared with a copolymer obtained by copolymerizing a non-fluorine functional group-containing monomer, and is processed at a high temperature (for example, 200 to 400 ° C.). Thermal decomposition and the like at the time can be further suppressed, a large adhesive strength can be obtained, and further, a coating layer free from coloring, foaming, pinholes, leveling defects and the like can be formed on the substrate. Further, even when the material is used at a high temperature, the adhesiveness is maintained, and further, defects of the coating layer such as coloring, whitening, foaming, and pinholes hardly occur.

Further, the functional group-containing fluoropolymer is
As such, it has not only heat resistance but also excellent properties such as chemical resistance, non-adhesion, antifouling, low friction, and weather resistance of fluoropolymers. Can be given without reduction.

The functional group of the functional group-containing fluorine-containing ethylenic polymer is at least one selected from a hydroxyl group, a carboxyl group, a carboxylate, a carboxylester group, and an epoxy group. It can provide adhesion of various layers constituting the solar cell module, such as the insulating substrate 1, the photovoltaic element 2, the transparent filler layer 3, and the surface film 4 shown in FIG.
The type and combination of the functional groups are appropriately selected depending on the type, purpose and application of the surface of the layer constituting the solar cell module,
Those having a hydroxyl group are most preferred in terms of heat resistance.

The functional group-containing fluorine-containing ethylenic monomer (a), which is one of the components constituting the functional group-containing fluorine-containing ethylenic polymer, is represented by the following formula (a-1): CX ₂ ＣCX ¹ —R _f —Y (1) (wherein, Y is —CH ₂ OH, —COOH, a carboxylate, a carboxyester group or an epoxy group, and X and X ¹ are the same or different, and are a hydrogen atom or a fluorine atom. ,
R _f is a divalent fluorinated alkylene group having 1 to 40 carbon atoms,
A fluorine-containing oxyalkylene group having 1 to 40 carbon atoms, a fluorine-containing alkylene group containing an ether group having 1 to 40 carbon atoms, or a fluorine-containing oxyalkylene group containing an ether bond having 1 to 40 carbon atoms) It is preferably a fluorine-containing ethylenic monomer.

Further, specific examples of the functional group-containing fluorine-containing ethylenic monomer (a-1) include a compound represented by the following formula (3): CF ₂ ＣＦCF—R _f ³ —Y (3) R _f ³ is the same as Y in the formula (1) and has 1 to 4 carbon atoms.
0 divalent fluorinated alkylene group or OR _f ⁴ (R _f ⁴ is a divalent fluorinated alkylene group having 1 to 40 carbon atoms or a divalent fluorinated alkylene group containing an ether bond having 1 to 40 carbon atoms) ], Formula (4): CF ₂ = CFCF ₂ -OR _f ⁵ -Y (4) [wherein, Y is the same as Y in formula (1), and R _f ⁵ has 1 to 3 carbon atoms.
9 divalent fluorine-containing alkylene groups or 1 to 39 carbon atoms
Represents a divalent fluorine-containing alkylene group containing an ether bond of the formula], formula (5): CH ₂ ＣＦCFCF ₂ —R _f ⁶ —Y ¹ (5) [wherein, Y ¹ represents Y in formula (1) Same, R _f ⁶ has 1 to 1 carbon atoms
39 divalent fluorine-containing alkylene groups, or OR _f ⁷ (R
_f ⁷ represents a divalent fluorine-containing alkylene group) containing an ether bond of the divalent fluorine-containing alkylene group or 1 to 39 carbon atoms to 39 carbon atoms or formula _{(6): CH 2 = CH} -R _f ⁸ -Y (6) [in the formula, Y is the same as Y in formula (1), R _f ⁸ is 1 to 4 carbon atoms
And a divalent fluorine-containing alkylene group of 0].

The functional group-containing fluorine-containing ethylenic monomers of the formulas (3) to (6) have relatively good copolymerizability with the fluorine-containing ethylenic monomer (b) having no functional group. This is preferred because it does not significantly reduce the heat resistance of the copolymer obtained.

Among these, the formulas (3) and (5) are preferable in view of copolymerizability with the fluorine-containing ethylenic monomer (b) having no functional group and heat resistance of the obtained polymer. The compound of the formula (5) is preferred, and the compound of the formula (5) is particularly preferred.

As the functional group-containing fluorine-containing ethylenic monomer represented by the formula (3),

[0051]

Embedded image

And the like.

As the functional group-containing fluorine-containing monomer represented by the formula (4),

[0054]

Embedded image

And the like.

As the functional group-containing fluorine-containing monomer represented by the formula (5),

[0057]

Embedded image

And the like.

The functional group-containing fluorine-containing monomer represented by the formula (6) includes

[0060]

Embedded image

And the like.

Others

[0063]

Embedded image

And the like.

The fluorine-containing ethylenic monomer (b) having no functional group and copolymerizing with the functional group-containing fluorine-containing ethylenic monomer (a) can be appropriately selected from known monomers. Gives polymers with chemical properties, chemical resistance, weather resistance, antifouling properties, non-adhesiveness, and low friction.

Specific fluorinated ethylenic monomer (b)
As tetrafluoroethylene, formula (2): CF ₂
ＣＦCF—R _f ¹ [R _f ¹ represents CF ₃ or OR _f ² (R _f ² represents a C 1-5 perfluoroalkyl group)], chlorotrifluoroethylene, vinylidene fluoride, vinyl fluoride, Hexafluoroisobutene,

[0067]

Embedded image

(Wherein X ² is selected from a hydrogen atom, a chlorine atom or a fluorine atom, and n is an integer of 1 to 5).

Further, in addition to the fluorine-containing ethylenic monomer having a functional group (a) and the fluorine-containing ethylenic monomer having no functional group (b), heat resistance and non-adhesiveness are not reduced. An ethylenic monomer having no fluorine atom within the range may be copolymerized. In this case, the ethylenic monomer having no fluorine atom has 5 carbon atoms in order not to lower the heat resistance.
It is preferable to select from the following ethylenic monomers, and specific examples include ethylene, propylene, 1-butene and 2-butene.

The content of the functional group in the functional group-containing fluorine-containing ethylenic polymer used in the present invention is 0.05 to 30 mol% of the total amount of the monomers in the polymer. The content of the functional group depends on the types of layers constituting the solar cell module,
It is appropriately selected according to differences in shape, film forming method, conditions, purpose and application, but is preferably 0.05 to 20 mol%, particularly preferably 0.1 to 10 mol%.

When the content of the functional group is less than 0.05%, it is difficult to obtain sufficient adhesiveness with various layers constituting the solar cell module, and it may be difficult to obtain a temperature change, ultraviolet irradiation, rainwater penetration, or the like. It is easy to peel off. Also, 30
If it exceeds mol%, the heat resistance will be reduced, and when firing at a high temperature or using at a high temperature, poor adhesion, coloring, foaming, pinholes, etc. will occur, peeling of the coating layer and elution of decomposition products will occur. Easy to get up.

Preferred examples of the functional group-containing fluorine-containing ethylenic polymer used in the present invention are as follows.

(I) The functional group-containing fluorine-containing ethylenic monomer (a-1) is contained in an amount of 0.05 to 30 mol% based on the total amount of the monomer, and the monomer (a-1) is further added. 85 to 99.7 mol% of tetrafluoroethylene and the above formula (2): CF ₂ = CF-R _f ¹ (2) [R _f ¹ is CF ₃ , OR _f ² ( R _f ² is a polymer of the monomer 0.3 to 15 mole% represented by] selected from a perfluoroalkyl group) having 1 to 5 carbon atoms (I). For example, a tetrafluoroethylene-perfluoro (alkyl vinyl ether) polymer having a functional group (reactive PFA) or a tetrafluoroethylene-hexafluoropropylene polymer having a functional group (reactive FEP).

This polymer (I) is the most excellent among fluorine-containing polymers in heat resistance, chemical resistance, weather resistance, antifouling property and non-adhesiveness, and particularly has a high continuous use temperature and a high temperature. It is excellent in that it can withstand processing and use, and is easy to wipe off dirt and dust due to its non-adhesiveness, and it is easy to wipe off. It is also preferable in that it is flame retardant.

(II) The fluorine-containing ethylenic monomer having a functional group (a-1) is contained in an amount of 0.05 to 30 mol% based on the total amount of the monomer, and the monomer (a-1) is further added. Based on the total amount of the monomers excluding, a polymer of 40 to 80 mol% of tetrafluoroethylene, 20 to 60 mol% of ethylene and 0 to 15 mol% of other copolymerizable monomers (ethylene having a functional group) -Tetrafluoroethylene polymer (II) (reactive E
TFE).

The polymer (II) has particularly excellent mechanical strength while maintaining the excellent heat resistance, chemical resistance, and weather resistance of the fluorine-containing resin, and is hard and tough. Since it has excellent fluidity, it is excellent in that it can be easily formed and composited (laminated, etc.) with other polymers. It is also preferable because of high transparency and flame retardancy.

(III) Polymer (III) comprising 0.05 to 30 mol% of a functional group-containing fluorine-containing ethylenic monomer (a-1) and 70 to 99.9 mol% of vinylidene fluoride (reactive P
VdF).

The polymer (III) has particularly excellent mechanical strength while maintaining the excellent heat resistance and weather resistance of the fluorine-containing resin, and is hard and tough. Since it is excellent, it is excellent in that it can be easily formed and composited (laminated, etc.) with other polymers.

(IV) 0.01 to 3 with respect to the total amount of the monomers
0 mol% of a functional group-containing fluorine-containing ethylenic monomer (a-
1) and a mixed monomer of 70 to 99 mol% of vinylidene fluoride and 1 to 30 mol% of tetrafluoroethylene based on the total amount of the monomers except for the monomer (a-1) a-
1) Vinylidene fluoride is added to the total amount of the monomers except for 50).
To 99 mol%, 0 to 30 mol% of tetrafluoroethylene and 1 to 20 mol% of chlorotrifluoroethylene, or the total amount of the monomers excluding the monomer (a-1). Polymer (IV) with a mixed monomer of vinylidene fluoride 60 to 99 mol%, tetrafluoroethylene 0 to 30 mol%, and hexafluoropropylene 1 to 10 mol%
(Reactive VdF copolymer).

Since this polymer (IV) has a low melting point while maintaining the excellent weather resistance of the fluorine-containing resin, it can be used at room temperature to 100 ° C.
Processing at a temperature as low as possible is possible, and particularly preferred is a composite (such as lamination) with a non-fluorine polymer having no heat resistance. Further, it is excellent in flexibility, flexibility and transparency, and can be used not only as a cover film but also as a filler and a sealing material. The reactive group of the fluoropolymer of the present invention is preferable because it can easily crosslink not only with an adhesive function but also with a curing agent and can improve mechanical properties.

(V) 0.05 to 3 based on the total amount of the monomers
0 mol% of a functional group-containing fluorine-containing ethylenic monomer (a-
1) and 40 to 90 mol% of vinylidene fluoride, 0 to 30 mol% of tetrafluoroethylene, and hexafluoropropene 1 based on the total amount of the monomers except for the monomer (a-1).
0 to 50 mol% of the mixed monomer, and tetrafluoroethylene 40% based on the total amount of the monomer except the monomer (a-1)
To 70 mol%, propylene 30 to 60 mol%, and other monomers copolymerizable therewith (for example, vinylidene fluoride, hexafluoropropylene, chlorotrifluoroethylene, perfluorovinyl ethers and the like) 0 to 20
Mol% of the mixed monomer, or tetrafluoroethylene 40 to 100% based on the total amount of the monomer excluding the monomer (a-1)
85 mol%, perfluorovinyl ethers 15 to 60
Polymer (V) with a mole% of mixed monomer (reactive fluoro rubber).

This polymer (V) has good adhesion to metals, elements, electrodes, etc., while maintaining the excellent heat resistance, chemical resistance, weather resistance, and flame retardancy of fluororubber. Or when used as a sealing material. In addition to the adhesive function, crosslinking with a curing agent is also possible using the reactive group of the polymer of the present invention, and crosslinking at a low temperature is also possible by selecting a curing agent. As a result, it is excellent in that mechanical strength can be improved while maintaining transparency.

The functional group-containing fluorine-containing polymer is obtained by polymerizing the above-mentioned functional group-containing fluorine-containing ethylenic monomer (a) and the fluorine-containing ethylenic monomer having no functional group (b) by a known method. It can be obtained by copolymerizing by a method. Among them, a method based on radical copolymerization is mainly used. That is, the means for initiating the polymerization is not particularly limited as long as it proceeds radically, but is initiated by, for example, an organic or inorganic radical polymerization initiator, heat, light or ionizing radiation. As the type of polymerization, solution polymerization, bulk polymerization, suspension polymerization, emulsion polymerization, or the like can be used. The molecular weight is controlled by the concentration of the monomer used for the polymerization, the concentration of the polymerization initiator, the concentration of the chain transfer agent, and the temperature. The composition of the resulting copolymer can be controlled by the composition of the charged monomers.

The solar cell material comprising the functional group-containing fluorine-containing ethylenic polymer described above can take various forms as a material to be applied to various layers constituting a solar cell module. Typically, it is in the form of a film-like material, but in the form of a viscous fluid or powder, such as liquid rubber, or in the form of a paint or adhesive, which has a form in which a polymer is dissolved or dispersed in water or a solvent. The composition may be in the form of a neutral composition.

Among them, the formation into a film can be carried out by a conventional method such as a melt molding method (extrusion method, hot press method, etc.), a cutting method, a casting method and the like. In addition, a fluid composition such as a paint is a polymer obtained by the above-described polymerization method and, if necessary, additives such as a stabilizer, a reinforcing agent, a filler, and an ultraviolet absorber that do not decrease transparency. May be adjusted according to a conventional method such as mixing in a medium (water or solvent) using a blender or a mill. The composition and shape of each material will be described later in the description of each material.

The solar cell material of the present invention will be described in accordance with the basic type of the solar cell module conceptually shown in FIG.

The solar cell material of the present invention can be applied as a surface material. The surface material is a material disposed on the outermost surface on the light incident side of the solar cell module, and is often exposed directly to outdoor weather and environmental changes.

The surface material basically needs to transmit visible light, and it is necessary to prevent a decrease in the transmittance due to adhesion of dirt, dust, and dust when used outdoors. Further, it is necessary to maintain weather resistance and heat resistance in an outdoor environment. Therefore, various uses of a fluororesin film as a surface material have been studied. As described above, the conventional fluororesin surface material has a problem that the adhesion to the substrate is insufficient and the workability is poor. However, a surface material having good adhesiveness can be obtained by using the fluoropolymer of the present invention. As the surface material, specifically, a surface film formed into a film shape may be laminated, or a coating composition may be applied. Further, it may be produced by combining film lamination and application of paint. In particular, the use of a preformed surface film for the surface material, or any layer of the surface material, forms a uniform coating layer on the entire surface of the base material and provides uniform adhesion without uneven adhesion. In view of the above, as a result, pinholes and the like hardly occur, and this is preferable in that the insulating property is maintained.

The surface film of the present invention comprises: (a) a functional group-containing fluorine-containing ethylene having at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, a carboxylate, a carboxyester group and an epoxy group. (B) at least one monomer of the above-mentioned fluorine-containing ethylenic monomer not having a functional group; It is a fluorine-containing adhesive film formed by molding a functional group-containing fluorine-containing ethylenic polymer having a functional group obtained by copolymerizing 95 mol% with no need for surface treatment or use of a general adhesive. It can be adhered to the substrate of the solar cell, thereby giving the substrate excellent weather resistance, antifouling property and non-adhesion of the fluoropolymer.

In this case, the film itself has heat resistance, chemical resistance, mechanical properties, non-adhesiveness, etc.
Efficient film forming such as melt forming is possible, it has good formability, it can be made thin and uniform, and it can be melted by various thermocompression bonding methods and it can be applied to various substrates (I), (II), (III) or (I)
A surface film comprising the polymer of V) is preferred.

For example, polymer (I) (reactive PFA, F
The surface film made of EP) is the most excellent among fluoropolymers in heat resistance, chemical resistance, weather resistance, and non-adhesiveness. Particularly, it has a high continuous use temperature and can withstand high temperature processing and use. In addition, it is excellent in that it is easy to wipe off dirt and dust and easy to wipe off due to its non-adhesiveness. It is also preferable in that it is flame retardant.

The surface film composed of the polymer (II) (reactive ETFE) has particularly excellent mechanical strength while maintaining excellent heat resistance, chemical resistance and weather resistance of the fluoropolymer, It is excellent in that it is hard and tough, and has excellent melt fluidity, so that it can be easily formed and compounded with other polymers (such as lamination). It is also preferable because of high transparency and flame retardancy.

The surface film made of the polymer (III) (reactive PVdF) has particularly excellent mechanical strength while maintaining excellent heat resistance and weather resistance of the fluoropolymer, and is hard and tough. At a certain point, and because of its excellent melt fluidity, it is excellent in that it is easy to process and form a composite with other polymers (such as lamination).

Since the surface film made of the polymer (IV) (reactive VdF copolymer) has a low melting point while maintaining the excellent weather resistance of the fluoropolymer, it can be used at a temperature as low as room temperature to about 100 ° C. Processing is possible, and it is particularly preferable in the case of a composite (such as lamination) with a non-fluorine polymer having no heat resistance. Further, it is excellent in flexibility, flexibility and transparency, and can be used not only as a cover film but also as a filler and a sealing material. The reactive group of the fluoropolymer of the present invention is preferable because it can easily crosslink not only with an adhesive function but also with a curing agent and can improve mechanical properties.

The thickness of the surface film is usually 10 to 200 μm.
m, preferably 30 to 100 μm.

Further, the surface film of the present invention contains a layer of the fluoropolymer having a functional group of the present invention, and a transparent layer made of another material may be provided by lamination or coating. Preferred examples thereof include (A-1) a layer comprising a functional group-containing fluoropolymer of the present invention and (B-1) a layer comprising a fluorine-containing ethylenic polymer having no functional group in a side chain. It is a surface film made.

That is, one surface has adhesiveness to the substrate by a layer made of a fluorine-containing ethylenic polymer having a functional group, and the other surface is a layer made of a general fluorine-containing polymer, By bringing the surface of the adhesive into contact with the base material and bonding it by operations such as thermocompression bonding, the excellent properties of the fluorine-containing polymer, such as excellent chemical resistance, weather resistance, stain resistance, and non-adhesion, can be obtained from the base material. Alternatively, it can be provided to a laminate including a substrate.

The fluorine-containing ethylenic polymer (B-1) having no functional group in the side chain in the surface film obtained by laminating (A-1) and (B-1) of the present invention is specifically described below. Is PF
A, FEP, ETFE, ECTFE, PVDF, and vinylidene fluoride-based copolymer are preferable in that the excellent properties of the above-mentioned fluoropolymer can be imparted to the substrate and the laminate including the substrate.

The surface film composed of the two-layer laminate of the present invention can be variously selected, but each of the two layers is preferably a combination having good adhesion and compatibility with each other in terms of transparency and adhesion.

Specifically, the adhesive layer (A-1) of the two layers imparts the same monomer composition and composition as the fluoropolymer layer (B-1) with adhesiveness. It is preferably selected from a polymer obtained by copolymerizing a fluorine-containing ethylenic monomer (a) having a functional group.

More specifically, i) (A-1) polymer (I) (so-called reactive PFA,
A fluorine-containing adhesive film obtained by laminating a layer composed of (FEP) and a layer composed of at least one polymer selected from the group consisting of (B-1) PFA and FEP has the highest heat resistance, It is preferable because it has excellent properties such as chemical property and non-adhesiveness.

Ii) A fluorine-containing adhesive film obtained by laminating a layer composed of (A-1) polymer (II) (so-called ETFE having a functional group) and a layer composed of (B-1) ETFE is excellent. It is preferable because it has excellent melt molding processability in addition to heat resistance, chemical resistance, mechanical properties and the like.

Iii) (A-1) at least one polymer selected from polymer (III) (so-called functional group-containing PVDF) and polymer (IV) (so-called functional group-containing VdF copolymer)
A fluorine-containing adhesive film obtained by laminating a layer composed of a seed and a layer composed of at least one polymer selected from the group consisting of (B-1) PVDF and vinylidene fluoride-based copolymer,
It is preferable because it has excellent moldability.

The thickness of the two-layer surface film of the present invention is 10 to 500 μm, preferably 30 to 500 μm in total.
It is 200 μm, particularly preferably 40 to 100 μm.

The thickness of each layer is set to 5 to 20 for the adhesive layer (A-1).
0 μm, fluoropolymer layer (B-1) 5 to 495 μm
Of the adhesive layer (A-1) 1
0 to 100 μm, fluorine-containing polymer layer (B-1) 20 to
490 μm, particularly preferably (A-1) 10 to 50 μm
m, (B-1) 30 to 90 μm.

In the present invention, suitable reinforcing agents, fillers, stabilizers,
It is also possible to incorporate an ultraviolet absorber, a pigment and other additives as appropriate. With such additives, it is also possible to improve thermal stability, surface hardness, weather resistance, chargeability, etc.

In the surface film of the present invention, the adhesive which can be melt-molded such as the above-mentioned polymers (I), (II), (III) and (IV) employs compression molding, extrusion molding and the like. In particular, melt extrusion is the preferred method for reasons such as productivity and quality.

In the present invention, the integral bonding of the two-layer surface film (A-1) and (B-1) is performed by combining (A-1) and (B-1).
-1) A method of superimposing and molding each formed film, a method of coating the other on one formed film, and a method of achieving joint joining simultaneously with film forming by a multi-layer coextrusion method. A multi-layer coextrusion molding method is preferable in view of productivity and quality.

The solar cell material of the present invention is also useful as a material for a transparent filler layer. As described above, the transparent filler layer is required to have impact resistance (buffer) in addition to transparency, weather resistance, and heat resistance. From this viewpoint, the polymer (V) is further required to be flame-retardant. (Reactive fluoro rubber) is optimal.

Further, the filler layer using the reactive fluoro rubber of the present invention can be vulcanized and adhered by mixing a vulcanizing agent. As the vulcanization method, an organic peroxide vulcanization method, a polyol vulcanization method, and an amine vulcanization method, which are ordinary vulcanization methods for fluororubber, can be employed.

For example, when vulcanizing an organic peroxide,
A monomer containing bromine or iodine may be copolymerized with fluororubber for the purpose of introducing a vulcanization site, or a chain transfer agent containing iodine may be used during polymerization, or bromine or iodine may be used as a vulcanization site. Vulcanizing organic bases such as organic onium compounds such as organic quaternary ammonium salts and organic quaternary phosphonium salts, nitrogen-containing organic compounds such as amines and imines, and organic phosphorus compounds such as phosphines and phosphites It may be used as an accelerator. When bromine or iodine is introduced as a vulcanization site, an unsaturated polyfunctional compound is used as a vulcanization aid. When an organic base is used as a vulcanization accelerator, a divalent metal oxide or hydroxide is used as an acid acceptor.

Examples of the organic peroxide include benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (peroxybenzoate) hexyne-3,1,4-bis (t
tert-butylperoxyisopropyl) benzene, lauroyl peroxide, tert-butylperacetate, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3, 2,5-dimethyl-2,
5-di (tert-butylperoxy) hexane, te
rt-butyl perbenzoate, tert-butyl perphenyl acetate and the like are used. Examples of the unsaturated polyfunctional compound include triallyl isocyanurate, triallyl cyanurate, trimethylolpropane trimethacrylate, and polybutadiene.

Examples of the organic base include tetrabutylammonium hydrogen sulfate, tetrabutylammonium bromide,
8-benzyl-1,8-diazabicyclo [5.4.0]
-7-undecenium chloride, p-toluenesulfonic acid 1,8-diazabicyclo [5.4.0] -7-undecenium, tetrabutylphosphonium chloride, trioctylmethylphosphonium chloride, triphenylbenzylphosphonium chloride, 1,8 -Diazabicyclo [5.4.0] -7-undecene, pyridine, tributylamine, triphenylphosphine, tributylphosphite and the like are used.

In the case of polyol vulcanization using a polyhydroxy compound as a vulcanizing agent, an organic onium compound is used as a vulcanization accelerator, and a divalent metal oxide or hydroxide is used as an acid acceptor. . As the polyhydroxy compound, any of the known compounds used for vulcanizing the polyol of fluororubber can be used, and among them, aromatic polyhydroxy compounds such as bisphenol AF, bisphenol A, and hydroquinone are preferably used.

As the organic onium compound, any of the known compounds used for vulcanizing the polyol of fluororubber can be used, and quaternary phosphonium salts such as triphenylbenzylphosphonium chloride and trioctylmethylphosphonium chloride, and tetrabutylammonium Bromide, tetrabutylammonium hydrogen sulfate, 8-
Benzyl-1,8-diazabicyclo [5.4.0] -7
-Quaternary ammonium salts such as undecenium chloride, iminium salts, sulfonium salts and the like are used.

In the case of amine vulcanization using a polyamine compound as a vulcanizing agent, a divalent metal oxide or hydroxide is used as an acid acceptor. As the polyamine compound, all known compounds used for amine vulcanization of fluororubber can be used, and hexamethylenediamine,
Hexamethylene diamine dicarbamate, disinnamylidene hexamethylene diamine, and the like are used. Also,
As the acid acceptor, oxides or hydroxides of magnesium, calcium, zinc, lead and the like are used.

The elastomeric fluorine-containing adhesive thus obtained can be adhered to or laminated on a substrate by a conventionally known method such as extrusion, coextrusion, and coating.

By utilizing the reactive group in the reactive fluororubber of the present invention, the adhesiveness of the base material to the insulating substrate, the element, and the metal reinforcing layer can be improved. Still further, the reactive group can be cross-linked by reacting itself or a general curing agent,
Crosslinking at about room temperature is possible, and mechanical properties can be improved while maintaining transparency. When cross-linking by reaction with a curing agent using these functional groups, examples of the curing agent include general curing agents such as isocyanate-based, epoxy-based, polyol-based, polycarboxylic acid-based, acid anhydride-based, and silicon-based curing agents. Is available.

Further, the transparent filler layer may be made of glass wool, glass fiber, glass nonwoven fabric, or the like to prevent scratches and breaks during construction, damage to rain, snow, hail, hail, etc., and leakage accidents due to cracks. A glass-based material may be blended and strengthened to improve scratch resistance and impact resistance. In addition, additives such as a curing agent, a curing accelerator, and an ultraviolet absorber may be blended, but the amount should be an amount which does not impair the above-mentioned required properties.

When the material of the present invention is applied to a surface material typified by a surface film, a material conventionally used as a material for the transparent filler layer, for example, disclosed in JP-A-7-297439. Ethylene as described
Vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, urethane resin, butyral resin, silicone resin, etc., or vinylidene fluoride described in JP-A-7-302925 A fluorine rubber such as a ride (VdF) -hexafluoropropylene (HFP) copolymer may be used.

In particular, EVA is preferable because it has transparency, flexibility and flexibility, has good adhesion to elements and insulating base materials, and is inexpensive. Further, EVA crosslinked with an organic peroxide or the like is preferable in terms of heat resistance and weather resistance.

The maximum thickness of the transparent filler layer is usually about 50 to 1000 μm, preferably 300 to 600 μm.

Further, as a member or a layer of a solar cell module to which the solar cell material of the present invention can be applied, an adhesive layer for bonding to a member (layer) not using the material of the present invention, In order to seal so that water or the like does not penetrate, a sealing material, an insulating base material, and the like for joining modules or a module and a base material such as another building material may be used. When applied to those members, the polymers (I) to (I) may be used depending on the properties required for the members.
The polymer may be selected from (V).

Next, the solar cell module of the present invention produced using the solar cell material of the present invention will be described.

As a basic structure of the solar cell module of the present invention, at least one of one or two or more coating materials provided on the light incident side of the photovoltaic element is the solar cell material of the present invention. It is formed.

The solar cell module has, for example, the basic structure shown in FIG.

As another embodiment of the solar cell module, there is a solar cell module whose schematic sectional view is shown in FIG. 2, for example. In the embodiment shown in FIG. 2, the surface film 14, the transparent filler layer 13,
The photovoltaic element 12, the back filler layer 15, the insulating layer 11, the back filler layer 15, and the reinforcing layer 16 are stacked in this order.

Examples of the coating material on the light incident side of the module of the present invention include surface films 4 and 14 and transparent filler layers 3 and 13. And so on.

As the surface film and the transparent filler layer, the above-mentioned materials can be suitably applied.

Further, in the embodiment shown in FIG. 2, the material for a solar cell of the present invention may be applied to the backside filler layer. In that case, transparency is not required, but it is preferable to use the above-mentioned polymers (I) to (V) from the viewpoint of adhesiveness, and to use the above-mentioned polymer (VI) when importance is placed on the buffering property. Of course, EVA or butyral resin may be used as in the conventional case.

The photovoltaic element does not need to have a special specification for the module of the present invention, and one containing a semiconductor active layer or a compound semiconductor layer, particularly a silicon-based semiconductor layer is used. Examples of the silicon-based semiconductor layer include an amorphous silicon semiconductor layer, a single-crystal silicon semiconductor layer, and a polycrystalline silicon semiconductor layer. However, the silicon-based semiconductor layer has mass productivity, can be reduced in cost, is lightweight, has a low installation cost, is flexible. A material including an amorphous silicon semiconductor layer is preferable because it has flexibility, can be bent, can be installed in any location, and can be installed locally.

As the insulating layers 1 and 11, those conventionally used can be used as they are. For example, polyamide, fluororesin represented by polyvinyl fluoride, polyimide, polyetherimide, polyethersulfone, PPS,
An electrically insulating material such as polyetherketone may be used.

The reinforcing layer 16 is provided to provide mechanical strength to the solar cell module and prevent thermal deformation. For example, a steel sheet such as a dull steel sheet and a carbanium steel sheet, various plastic sheets, and FRP are used. .

As described above, the fluorine-containing polymer containing the functional group of the present invention can be used in various parts of the solar cell module.

Next, preferred combinations of solar cell modules formed using the solar cell material of the present invention will be specifically described. The numbers in parentheses are the symbols indicating the respective layers in FIG. 1 or FIG.

I) A surface film formed by molding the polymer (II) (reactive ETFE) or the polymer (IV) (reactive VdF copolymer) (14) ii) A transparent film made of EVE reinforced with a glass nonwoven fabric Filler layer (13) iii) Photovoltaic device made of amorphous silicon (1
2) iv) Backside filler layer made of stainless steel plate (15) v) Insulating substrate made of PET film (11) vi) Solar cell module consisting of reinforcing layer made of galvanium steel plate (16) has good productivity It is preferable in that it is lightweight, has high flexibility, can be bent, and is easy to construct.

I) Surface film formed by molding ETFE or VdF copolymer (14) ii) Transparent filler layer made of crosslinked polymer (V) (reactive fluororubber) (13) iii) Amorphous Silicon photovoltaic device (1
2) iv) Backside filler layer made of SUS plate (15) v) Reinforcement layer made of galvanium steel plate (16) It is preferable in terms of properties.

I) Polymer (I) (Reactive PFA, FE
P) Surface film formed by molding (14) ii) Transparent filler layer made of EVE reinforced with glass nonwoven fabric (13) iii) Photovoltaic element made of amorphous silicon (1)
2) iv) Backside filler layer composed of stainless steel plate (15) v) Insulating substrate composed of PET film (11) vi) Solar cell module composed of reinforcing layer composed of galvanium steel sheet (16) It is particularly preferable because it has excellent non-adhesiveness, is lightweight, has high flexibility, can be bent, and is easy to construct.

I) Polymer (I) (Reactive PFA, FE
P) A surface film formed by molding (4) ii) A photovoltaic element made of polycrystalline silicon (2 iii) A solar cell module consisting of a glass insulating plate (1) has anti-fouling and non-adhesive properties Further, it is preferable because it has the effect of preventing breakage and scattering.

In the solar cell module of the present invention, for example, the materials and elements of the respective layers in the form of a film are stacked in the order shown in FIG. 2, and a heat-pressing method such as a hot roll method or a hot pressing method, a high frequency heating method, a microwave heating method, Each layer and element can be pressed by a vacuum pressing method (such as a vacuum pressing method) or a pneumatic method.

By the way, expectations for solar cells as a supply source of clean energy are increasing.
Since the amount of power obtained by a solar cell is proportional to the area of the solar cell, a large solar cell installation site is required to obtain a large amount of power. Utilizing a house roof as such an installation location is also suitable in that it is close to a power consuming location.

The simplest method of installing a solar cell on a building material such as a roof of a house or the like is to install a gantry on a roof tile by fixing the gantry to a roof structural member with a metal fitting or the like. This is a method of installing a module including a solar cell element. However, in this case, the gantry or module becomes a structure independent of the roof, which not only requires great strength, but also the gantry and the solar cell module impair the aesthetics of the house or building. There is a problem.

Therefore, as an alternative, a building material in which a module such as a solar cell tile is integrated has been developed. This solar cell building material is formed by directly forming a solar cell element on a base material, or by attaching or embedding a solar cell element to a base material.

As described above, the greatest feature of the present invention is that by using a fluoropolymer having excellent adhesiveness, it is possible to avoid blending of various additives and use of an adhesive which impair transparency. In addition, excellent adhesiveness can be obtained without special treatment. By improving the adhesiveness, as a result, the transparency, the antifouling property and the weather resistance are improved, and the photoelectric conversion efficiency of the solar cell is improved.

Therefore, a large number of the solar cell modules of the present invention are arranged in series or in parallel, and this is exposed to sunlight such as building materials, for example, roof panels, soundproof walls, wall materials for buildings, glass curtain walls and metal curtain walls. An excellent clean power source can be obtained by arranging the power supply in a portion where the power is supplied. The arrangement method and the like may be a conventional method.

[0146]

EXAMPLES The present invention will be described below based on Synthesis Examples, Reference Examples and Examples, but the present invention is not limited thereto.

Synthesis Example 1 (Synthesis of PFA having hydroxyl group) Pure water (1500 ml) was placed in a 6-liter glass-lined autoclave equipped with a stirrer, a valve, a pressure gauge, and a thermometer.
After sufficiently purging with nitrogen gas, vacuum is applied and 1,2-dichloro-1,1,2,2-tetrafluoroethane (R-1
14) 1500 g was charged.

Then, perfluoro- (1,1,9,9
-Tetrahydro-2,5-bistrifluoromethyl-
3,6-dioxa-8-nonenol) (formula 7)

[0149]

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5.0 g, perfluoro (propyl vinyl ether) (PPVE) 130 g, methanol 180
g was injected using nitrogen gas, and the temperature in the system was maintained at 35 ° C.

While stirring, tetrafluoroethylene gas (TFE) was injected so that the internal pressure became 8.0 kgf / cm ² G. Then, 0.5 g of a 50% methanol solution of di-n-propylperoxydicarbonate was added to
The reaction was started by injecting with nitrogen.

[0152] Since the pressure lowered with the progress of the polymerization reaction, re-pressurized with tetrafluoroethylene gas at the time when decreased to 7.5 kgf / cm ² G to 8.0 kgf / cm ^2, the step-down was repeated booster .

While continuing the supply of tetrafluoroethylene, about 60% of tetrafluoroethylene gas was supplied from the start of polymerization.
Every time the g was consumed, 2.5 g of the fluorine-containing ethylenic monomer having a hydroxy group (the compound represented by the formula 7) was injected 9 times in total (22.5 g in total) to continue the polymerization. , About 600 g of tetrafluoroethylene from the start of polymerization
Stop the supply at the time of consumption, cool the autoclave,
Unreacted monomer and R-114 were released.

The obtained polymer was washed with water and methanol, and then dried under vacuum to obtain 710 g of a white solid (powder). The composition of the obtained copolymer was ¹⁹ F-
According to NMR analysis and IR analysis, TFE / PPVE / (formula 7
= 97.0 / 2.0 / 1.0 mol%). In addition, the infrared spectrum shows -O at 3620 to 3400 cm ^-1 .
H characteristic absorption was observed. Tm = 3 by DSC analysis
Decomposition starting point: 365 ° C, 1% by DTGA analysis at 05 ° C
The thermal decomposition temperature Td was 375 ° C. Using a nozzle with a diameter of 2 mm and a length of 8 mm using a Koka type flow tester,
The melt flow rate was measured at 372 ° C. for 5 minutes with a load of 7 kgf / cm ² and found to be 32 g / 10 min.

The obtained white powder was extruded at 350 to 370 ° C. with a twin screw extruder (Labo Plastmill, Toyo Seiki Co., Ltd.) to produce pellets.

Synthesis Example 2 (Synthesis of PFA having hydroxyl group) Pure water (1500 ml) was placed in a 6-liter glass-lined autoclave equipped with a stirrer, a valve, a pressure gauge, and a thermometer.
After sufficiently purging with nitrogen gas, vacuum is applied and 1,2-dichloro-1,1,2,2-tetrafluoroethane (R-1
14) 1500 g was charged.

Next, perfluoro- (1,1,9,9
-Tetrahydro-2,5-bistrifluoromethyl-
10,6-Dioxa-8-nonenol) (formula 7).
2 g, perfluoro (propyl vinyl ether) (PP
VE) 130 g and methanol 180 g were injected under pressure using nitrogen gas, and the temperature in the system was maintained at 35 ° C.

While stirring, tetrafluoroethylene gas (TFE) was injected so that the internal pressure became 8.0 kgf / cm ² G. Then, 0.5 g of a 50% methanol solution of di-n-propylperoxydicarbonate was injected under pressure using nitrogen to start the reaction.

[0159] Since the pressure lowered with the progress of the polymerization reaction, re-pressurized with tetrafluoroethylene gas at the time when decreased to 7.5 kgf / cm ² G to 8.0 kgf / cm ^2, the step-down was repeated booster .

While continuing the supply of tetrafluoroethylene, about 60% of tetrafluoroethylene gas was supplied from the start of polymerization.
Every time the g was consumed, 5.14 g of the fluorine-containing ethylenic monomer having a hydroxy group (compound represented by the formula 7) was injected 9 times in total (46.3 g in total) to continue the polymerization. From the start of polymerization, tetrafluoroethylene is about 600
The feed was stopped at the point when the g had been consumed, the autoclave was cooled, and the unreacted monomer and R-114 were released.

The obtained polymer was washed with water and methanol, and then dried under vacuum to obtain 721 g of a white solid (powder). The composition of the obtained copolymer was ¹⁹ F-
According to NMR analysis and IR analysis, TFE / PPVE / (formula 7
= 97.6 / 2.0 / 1.8 mol%). In addition, the infrared spectrum shows -O at 3620 to 3400 cm ^-1 .
H characteristic absorption was observed. Tm = 3 by DSC analysis
11 ° C., decomposition start temperature 368 ° C. by DTGA analysis, 1
% Thermal decomposition temperature Td = 362 ° C. The melt flow rate was measured with a nozzle having a diameter of 2 mm and a length of 8 mm using a Koka type flow tester at 372 ° C. for 5 minutes and a load of 7 kgf / cm ² , and the melt flow rate was measured to be 85 g / 10 min.
Met.

The obtained white powder was extruded at 350 to 370 ° C. with a twin screw extruder (Labo Plastmill, Toyo Seiki Co., Ltd.) to produce pellets.

Synthesis Example 3 (Synthesis of PFA containing no functional group)
Perfluoro (1,1,9,9-tetrahydro-2,
5-bistrifluoromethyl-3,6-dioxa-8-
Synthesis was performed in the same manner as in Synthesis Example 1 except that nonenol) (the compound represented by the formula (7)) was not used, and 240 g of methanol was used, to obtain 597 g of PFA containing no functional group.

The obtained PFA was analyzed in the same manner as in Synthesis Example 1. TFE / PPVE = 98.2 / 1.8 mol% Tm = 310 ° C. Td = 469 ° C. (1% weight loss) Melt flow rate = It was 24 g / 10 min.

The obtained white powder was extruded in the same manner as in Synthesis Example 1 to produce pellets.

Synthesis Example 4 (Synthesis of ETFE Having Hydroxyl Group) Into a 6-liter glass-lined autoclave equipped with a stirrer, a valve, a pressure gauge, and a thermometer, 1500 ml of pure water was placed, and the atmosphere was sufficiently replaced with nitrogen gas. Vacuum was applied and 1500 g of octafluorocyclobutane (C-318) was charged.

Then, perfluoro- (1,1,9,9
-Tetrahydro-2,5-bistrifluoromethyl-
3,6-dioxa-8-nonenol) (formula 7)

[0168]

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2.7 g of perfluoro (1,1,5-
5.7 g of trihydro-1-pentene) was injected under pressure using nitrogen gas, and the temperature in the system was maintained at 35 ° C.

The internal pressure was 9.0 kgf / while stirring.
A mixed gas of tetrafluoroethylene / ethylene (97: 3 mol%) which had been mixed in advance so as to have a cm ² G was injected. Next, 16 g of a 50% methanol solution of di-n-propylperoxydicarbonate was injected under pressure using nitrogen to start the reaction.

Since the pressure decreases with the progress of the polymerization reaction, when the pressure decreases to 8.5 kgf / cm ² G, the mixture is mixed with a tetrafluoroethylene / ethylene (65:35 mol%) mixed gas separately mixed in advance. 0.0kgf / cm
^The pressure was increased again to ² , and the pressure reduction and pressure increase were repeated.

[0172] Tetrafluoroethylene / ethylene (6
5:35 mol%) While continuing to supply the mixed gas, every time about 22 g of the tetrafluoroethylene / ethylene mixed gas is consumed from the start of the polymerization, the above-mentioned fluorine-containing ethylenic monomer having a hydroxy group (the above formula 7) 1.0 g of perfluoro (1,1,5-trihydro-1-pentene) and 1.0 g of perfluoro (1,1,5-trihydro-1-pentene) were injected 10 times in total, and the polymerization was continued. When about 210 g had been consumed, the feed was stopped and the autoclave was cooled to release unreacted monomer and C-318.

The obtained polymer was washed with water and methanol, and then dried under vacuum to obtain 187 g of a white solid (powder). The composition of the obtained copolymer was ¹⁹ F-
From NMR analysis, TFE / ethylene / perfluoro (1,1,5-trihydro-1-pentene) / (formula 7
= 64.0 / 33.4 / 1.8 / 0.8 mol%). The infrared spectrum is 3650-3400c.
Characteristic absorption of -OH was observed at m ^-1 . Tm = 206 ° C. by DSC analysis, decomposition start point 29 by DTGA analysis
3 ° C., 1% thermal decomposition temperature Td = 356 ° C. Using a nozzle having a diameter of 2 mm and a length of 8 mm using a Koka type flow tester, preheating at 297 ° C. for 5 minutes, load 5 kgf / cm ²
The melt flow rate was measured at 74 g / 10 m.
was in.

Synthesis Example 5 (Synthesis of ETFE Having Methyl Ester Group)
Into a 6-liter glass-lined autoclave equipped with a valve, a pressure gauge, and a thermometer, 1500 ml of pure water was charged, sufficiently purged with nitrogen gas, evacuated, and charged with 1500 g of octafluorocyclobutane (C-318).

Then, perfluoro- (9,9-dihydro-2,5-bistrifluoromethyl-3,6-dioxa-8-nonenoic acid) methyl (formula 8)

[0176]

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3.1 g of perfluoro (1,1,5-
5.7 g of trihydro-1-pentene) was injected under pressure using nitrogen gas, and the temperature in the system was maintained at 35 ° C.

The internal pressure was adjusted to 9.0 kgf / while stirring.
A mixed gas of tetrafluoroethylene / ethylene (97: 3 mol%) which had been mixed in advance so as to have a cm ² G was injected. Next, 16 g of a 50% methanol solution of di-n-propylperoxydicarbonate was injected under pressure using nitrogen to start the reaction.

Since the pressure decreases with the progress of the polymerization reaction, when the pressure decreases to 8.5 kgf / cm ² G, the mixture is mixed with a tetrafluoroethylene / ethylene (65:35 mol%) mixed gas separately mixed in advance. 0.0kgf / cm
^The pressure was increased again to ² , and the pressure reduction and pressure increase were repeated.

Tetrafluoroethylene / ethylene (6
While continuing to supply the mixed gas, every time about 22 g of the tetrafluoroethylene / ethylene mixed gas is consumed from the start of the polymerization, the above-mentioned fluorine-containing ethylenic monomer having a hydroxy group (the above formula 8) Compound shown)
1.0 g of perfluoro (1,1,5-trihydro-1-pentene) and 0.9 g of perfluoro (1,1,5-trihydro-1-pentene) were injected 10 times in total, and the polymerization was continued. About 210 g of tetrafluoroethylene / ethylene was consumed from the start of the polymerization. At this point, the feed was stopped and the autoclave was cooled, releasing unreacted monomer and C-318.

The obtained polymer was washed with water and methanol, and then dried under vacuum to obtain 184 g of a white solid (powder). The composition of the obtained copolymer was ¹⁹ F-
From NMR analysis, TFE / ethylene / perfluoro (1,1,5-trihydro-1-pentene) / (formula 8
(Fluorinated ethylenic monomer having a methyl ester group represented by the formula) = 64.7 / 33.0 / 1.5 / 0.8 mol%. The infrared spectrum is 1790 cm ^-1 .

[0182]

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The characteristic absorption of was observed. Tm = 214 ° C. by DSC analysis, decomposition start point 28 by DTGA analysis
5 ° C., 1% thermal decomposition temperature Td = 359 ° C. Using a nozzle having a diameter of 2 mm and a length of 8 mm using a Koka type flow tester, preheating at 297 ° C. for 5 minutes, load 5 kgf / cm ²
The melt flow rate was measured at 51 g / 10 m.
was in.

Synthesis Example 6 (Synthesis of ETFE containing no functional group) In Synthesis Example 4, the perfluoro (1,1,9,9-tetrahydro-
2,5-bistrifluoromethyl-3,6-dioxa-
Synthesis was performed in the same manner as in Synthesis Example 1 except that 8-nonenol) (the compound represented by the formula 7) was not used, to obtain 166 g of a white powder of ETFE containing no functional group.

The ETFE obtained in the same manner as in Synthesis Example 4 was analyzed. TFE / ethylene / perfluoro (1,1,5-trihydro-1-pentene) = 64.7 / 33.5 / 1.8
Mol% Tm = 226 ° C. Td = 368 ° C. (1% weight loss) Melt flow rate = 14 g / 10 min.

Synthesis Example 7 (Synthesis of Fluoropolymer Using Fluorine-Free Functional Group-Containing Monomer) Acetic acid was placed in a 1-liter stainless steel autoclave equipped with a stirrer, a valve, a pressure gauge, and a thermometer. 250 g of butyl, vinyl pivalate (VPi)
4 g of 4-hydroxybutyl vinyl ether (HBV) as a hydroxyl-containing monomer having no fluorine
E) 32.5 g and 4.0 g of isopropoxycarbonyl peroxide were charged, cooled to 0 ° C. with ice, filled with nitrogen gas and replaced, and evacuated to obtain 47.5 g of isobutylene (IB).
g and 142 g of tetrafluoroethylene (TFE).

While stirring, the mixture was heated to 40 ° C. and reacted for 30 hours. When the pressure in the reaction vessel dropped to 2.0 kg / cm ² or less, the reaction was stopped. When the autoclave was cooled and unreacted gas monomers were released, a butyl acetate solution of the fluoropolymer was obtained. The polymer concentration was 45%.

From the obtained fluorinated polymer solution in butyl acetate, the fluorinated polymer was taken out by a reprecipitation method and sufficiently isolated by drying under reduced pressure. ¹ H-NMR, ¹⁹ F
When the obtained fluoropolymer was analyzed by -NMR elemental analysis, TFE / IB / VPi / HBVE = 44 /
It was a polymer consisting of 34/15/7 mol.

Reference Example 1 (Preparation of Film by Extrusion of PFA Having a Hydroxyl Group) The pellet obtained in Synthesis Example 1 was used in a single screw extruder (Labo Plastmill, Toyo Seiki Co., Ltd.) at a temperature of 360 ° C. to 3 ° C.
Extruded at 80 ° C, roll temperature 120 ° C, width 10c
m, a film having a thickness of 100 to 150 μm was obtained.

Reference Example 2 (Production of a film by extrusion of PFA having a hydroxyl group) The same procedure as in Reference Example 1 was carried out except that the pellets obtained in Synthesis Example 2 were used, and the width was 10 cm and the thickness was 100 to 150 μm.
m film was obtained.

Reference Example 3 (Preparation of Film by Extrusion of PFA Containing No Functional Group) A film having a width of 10 cm and a thickness of 100 to 150 μm was prepared in the same manner as in Reference Example 1 except that the pellets obtained in Synthesis Example 3 were used. I got it.

Reference Example 4 (Production of ETFE Film Having Hydroxyl Group)
Put the white powder obtained in Synthesis Example 4 into a 100 mm
After setting in a press set at 70 ° C. and preheating for 30 minutes, compression molding was performed at 70 kg / cm ² for 1 minute to obtain a film having a thickness of 0.1 mm.

Reference Example 5 (Production of ETFE Film Having Methyl Ester Group)
A film having a thickness of 0.1 mm was obtained in the same manner as in Reference Example 4, except that the white powder obtained in Synthesis Example 5 was used.

Reference Example 6 (Production of ETFE Film Containing No Functional Group) Synthesis Example 6
A film having a thickness of 0.1 mm was obtained in the same manner as in Reference Example 4 except that the obtained white powder was used.

Examples 1 to 4 (Visible light transmittance of functional group-containing fluoropolymer film) PFA having functional groups obtained in Reference Examples 1, 2, 4, and 5
Alternatively, for each of the ETFE films, the light transmittance in a representative visible region was measured using Hitachi spectrophotometer V-3410. Table 1 shows the results.

Comparative Examples 1 and 2 (Visible light transmission of fluoropolymer film containing no functional group) The functional groups obtained in Reference Examples 3 and 6 were replaced with the films obtained in Reference Examples 1, 2, 4 and 5. Not including PFA or ET
The light transmittance in a typical visible region was measured in the same manner as in Example 1 except that the FE film was used. Table 1 shows the results.

[0197]

[Table 1]

Examples 5 to 8 (Adhesion between PFA film having hydroxyl group and metal) As a metal plate, a degreased chromium-treated aluminum plate, a pure aluminum plate, a dull steel plate or a galvanium steel plate having a thickness of 0.5 mm was used. Then, an adhesion test with a PFA film having a hydroxyl group (the film of Reference Example 1) was performed as follows. The results are shown in Table 2.

(Preparation of Test Piece for Peeling Test) FIG. 3 is a schematic perspective view of a laminate obtained for preparing a test piece for peeling test. As shown in FIG. 3, the width a from the end (100 m
In the part m), the hydroxyl group-containing fluorine-containing film obtained in Reference Example 1 was used as the adhesive 23, and the width b (5
0 mm), a spacer (aluminum foil) 22 having a thickness of 0.1 mm is sandwiched between the two metal plates 21 at 350 ° C.
After preheating (20 minutes), it was pressurized at 50 kg / cm ² for 1 minute.

The thickness of the layer of the adhesive 23 in each of the obtained laminates was 0.1 mm. Further, the laminate is set to a width c (2
5mm), and the metal plate 2 with spacers
1 was bent into a T-shape to obtain a test piece for a peel test. FIG. 5 shows a schematic perspective view of a test piece for a peel test obtained in FIG. 4.

(Peeling Test) JIS K6854-197
Orientec Co., Ltd. based on T-type peel test method 7
Measurement was performed at room temperature at a cross head speed of 50 mm / min using a Tensilon universal testing machine. Measurements were made of the maximum peel strength (kgf / 25 mm) and the minimum peel strength (kgf / 2
5 mm). Table 2 shows the results.

Comparative Examples 3 to 6 (Adhesion between PFA containing no functional group and metal) Reference Example 1
Preparation of a test piece and peel test were performed in the same manner as in Example 5 except that the PFA film having no functional group obtained in Reference Example 3 was used instead of the PFA film having a hydroxyl group. The results are shown in Table 2.

[0203]

[Table 2]

Example 9 (Adhesion between PFA having hydroxyl group and stainless steel) A laminated test plate was prepared as follows using a degreased SUS304 steel plate having a length of 150 mm, a width of 70 mm and a thickness of 0.5 mm as a metal plate. Was prepared. The PFA film containing a hydroxyl group obtained in Reference Example 4 and the PFA film containing no functional group obtained in Reference Example 5 were cut into the same size as the SUS plate.

Further, a polyimide film (Kapton 200-H manufactured by DuPont) was cut into a similar size as a release film.

FIG. 5 is a schematic sectional view of the laminate test plate obtained in FIG. As shown in FIG. 5, the hydroxyl group-containing PFA film 32, the PFA film 33 containing no functional group, and the polyimide film 34 were sandwiched between two SUS plates 31, and set in a press set at 350 ° C. , after preheat (20 minutes), 1 50 kg / cm ²
Pressed for minutes to obtain a laminated test piece.

After cooling, the SUS plate 31 in contact with the polyimide film 34 was removed, and the polyimide film 34 spontaneously peeled off at the interface of the PFA film 33 containing no functional group.

FIG. 6 shows a schematic cross-sectional view of the resulting three-layer laminate. As shown in FIG. 6, the SFA having good transparency was obtained by using the hydroxyl group-containing PFA film 32 as an adhesive layer.
A three-layer laminate of the US plate 31 and the PFA film 33 was obtained.

Further, 100 1-mm square bases were formed on the obtained three-layer laminate until it reached the base SUS plate with a cutter knife, and the center of the base was extruded 5 mm with an Erichsen tester. As a result, the films 32 and 33 did not peel off at all, but adhered firmly to the substrate. The PFA film showed strong adhesion to the SUS plate.

Comparative Example 7 (Adhesion between PFA Film Having No Functional Group and Stainless Steel) A laminate was obtained in the same manner as in Example 9 except that a PFA film having a hydroxyl group was not used. FIG.
1 shows a schematic cross-sectional view of the obtained laminate. As shown in FIG. 7, a SUS plate 31 and a PFA film 33 containing no functional groups
To obtain a laminate. Although the obtained laminate was apparently adhered, it could be easily peeled off.

Further, an Erichsen test was conducted in the same manner as in Example 9. In 60 out of 100 base stitches, peeling was performed centering on the cut.

Example 10 (Adhesion between PFA having a hydroxyl group and glass)
Using a Pyrex glass of 30 × 20 × 5 mm as a glass plate, the hydroxyl group-containing P obtained in Reference Example 1 was used.
An adhesion test with FA was performed as follows.

(Preparation of Test Piece for Tensile Shear Test) FIG. 8 is a schematic perspective view of a test piece for tensile shear test. As shown in FIG. 8, PFA having a hydroxyl group obtained in Reference Example 1
Film (width d 20 mm, length e 10 mm, thickness f
(0.1 mm) was used as an adhesive 35 between the Pyrex glass plates 36, a load of 3 kg was applied, and the mixture was left in an electric furnace at 350 ° C. for 30 minutes to obtain a test piece. The thickness of the layer of the adhesive 35 was adjusted to 0.1 mm by a spacer.

(Adhesive Strength) The adhesive strength was measured by a tensile shear method. FIG. 9 is a schematic explanatory view for explaining an apparatus used for measuring the adhesive strength. As shown in FIG.
The test jig 38 conforming to the shape of No. 7 was set on an Orientec Co., Ltd. Tensilon universal testing machine 39, and a tensile shear test was performed at a crosshead speed of 20 mm / min. The measurement showed the maximum adhesive strength (kgf / cm ² ).

(Warm Water Resistance Test) A test piece prepared in the same manner as above was immersed in warm water at 50 ° C. for 72 hours, and the appearance and adhesive strength were observed.

(Methanol Resistance Test) The test piece was immersed in methanol at room temperature for 72 hours, and the appearance of adhesiveness was observed.

The results are shown in Table 3.

Comparative Example 8 (Adhesion test between PFA having no functional group and glass) The PFA film having no functional group obtained in Reference Example 3 was used instead of the PFA film having a hydroxyl group of Reference Example 1. Except for the above, a test piece was prepared and various tests were performed in the same manner as in Example 10. Table 3 shows the results.

[0219]

[Table 3]

Example 11 (Adhesive durability between hydroxyl group-containing PFA film and glass) (Preparation of laminate for adhesion durability test) FIG. 10 shows a laminate test plate prepared for obtaining a laminate for adhesion durability test. FIG. 150 m long as shown in FIG.
m, length 120m in the center of a glass plate 40 70mm wide
m, the PFA film 32 having a hydroxyl group obtained in Reference Example 2 cut into a width of 40 mm is placed thereon, and a PFA film 33 having no functional group of the same size (Reference Example 3)
Film) and a polyimide film 34 (Example 9)
And an aluminum plate 41 having the same size as the glass plate 40, and then set on a press set at 350 ° C., preheated (20 minutes), and then
A laminate test plate was obtained by pressing at kg / cm ² for 1 minute. After cooling, the aluminum plate 41 and the polyimide film 34 were removed to obtain a laminate for an adhesion durability test.

FIG. 11 is a schematic sectional view of the laminated body for the adhesive durability test obtained in FIG.

(Weather Resistance Test) The above-mentioned hydroxyl group-containing PFA film 32 was used as an adhesive layer to obtain a P
The laminate obtained by laminating the FA film 33 on the glass plate 40 was put into an I-Super UV tester (manufactured by Iwasaki Electric Co., Ltd.), and an accelerated weather resistance test was performed. A sample having no change in appearance was marked with “○”.

(Heat Resistance Test) The laminate was left in an atmosphere at 150 ° C. for 12 hours. ○ those that have no change in appearance
And

(Temperature / humidity cycle) -40 ° C./1 hour, 8
5 ° C / 85% RH / 4 hours temperature / humidity cycle test
Cycled. A sample having no change in appearance was marked with “○”.

Table 4 shows the results of the various tests described above.

Comparative Example 9 (Adhesion durability between PFA film having no functional group and glass) The PFA film having no functional group obtained in Reference Example 3 was used in place of the hydroxyl group-containing PFA film. In the same manner as in Example 11, a test laminate was prepared and subjected to a durability test. Table 4 shows the results.

Comparative Example 10 (Adhesion durability of surface-treated FEP / EVA film / glass laminate) An EVA film (manufactured by Sumitomo Chemical Co., Ltd., Bond First 7B, thickness of 200 μm) was used instead of the hydroxyl group-containing PFA film. As an adhesive layer, a one-sided surface treated film of FEP (NEOFLON FEP film NF-0100B1 manufactured by Daikin Industries, Ltd.) was used instead of a PFA film containing no functional group, and the surface treated surface was EVA.
Surface treatment F was performed in the same manner as in Example 11 except that the film was superposed in contact with the film layer, and was press-bonded at a temperature of 180 ° C.
An EP / EVA / glass laminate was obtained. Using this, the same durability test as in Example 11 was performed. Table 4 shows the results.

[0228]

[Table 4]

Example 12 (Adhesion between hydroxyl group-containing PFA film and polyimide film) FIG. 12 shows an adhesion test (T-peel test).
1 is a schematic cross-sectional view of a laminate test plate prepared for obtaining a laminate used for the present invention. As shown in FIG. 12, the hydroxyl group-containing PFA film 32 obtained in Reference Example 1, the PFA film 33 containing no functional group and the polyimide film 34 obtained in Reference Example 3 (the same as Example 9) were used in the same manner as in Example 7. It was cut into a size, sandwiched between two SUS plates 31, and heated by a press in the same manner as in Example 9 to obtain a laminate test plate. After cooling, the SUS plate 31 was peeled off to obtain a laminate. FIG. 14 shows a schematic cross-sectional view of the obtained laminate.
Further, the laminate was cut into a width of 25 mm.

FIG. 14 is a schematic cross-sectional view of a laminate to be subjected to a T-peel test. As shown in FIG. 14, the interface between the polyimide film 34 and the hydroxyl group-containing PFA film 32 was partially peeled off, and a T-type peeling test was performed in the direction of the arrow shown in FIG. At an average peeling load of 4.0 kgf / 25 mm.

Comparative Example 11 (Adhesion between PFA Film Containing No Functional Group and Polyimide Film) FIG. 15 is a schematic sectional view of a laminate to be subjected to a T-peel test. As shown in FIG.
A part of the interface between the obtained polyimide film 34 having a width of 25 mm and the PFA film 33 containing no functional group was peeled off, and a T-type peel test was performed in the direction of the arrow shown in FIG. 15 in the same manner as in Example 12. No adhesion was shown.

Example 13 (Adhesion between Hydroxyl Group-Containing PFA Film and Polycrystalline Silicon) FIG. 16 is a schematic cross-sectional view of a laminate test plate prepared to obtain a laminate for an adhesion test. FIG.
As shown in the figure, a hydroxyl group-containing PFA film 32 (obtained in Reference Example 1) obtained by cutting a polycrystalline silicon plate 42 having a length of 75 mm and a width of 35 mm into the same size as the polycrystalline silicon plate 42 on the back side thereof. Glass plate 40 in between
On top. Next, on the surface side of the polycrystalline silicon plate 42, the hydroxyl group-containing PF
An A film 32 (obtained in Reference Example 1), a PFA film 33 containing no functional group (obtained in Reference Example 3), a polyimide film 34 (same as in Example 9), and a glass plate 40 A laminate test plate was obtained by applying a load of 1.5 kg thereon and heating at 350 ° C. for 20 minutes. After cooling, the outermost glass plate 40 was removed, and the polyimide film 34 was peeled off to obtain a laminate. FIG. 18 shows a schematic sectional view of the obtained laminate. As shown in FIG. 17, a hydroxyl group-containing PFA film 32 was used as an adhesive layer,
A laminate was obtained in which the polycrystalline silicon plate 42 and the PFA film 33 provided on the surface of the glass plate 40 had excellent transparency and were firmly adhered.

(Measurement of Adhesive Strength) FIG. 18 is a schematic sectional view of the laminate used for measuring the adhesive strength. As shown in FIG. 18, the films 33 and 32 adhered to the surface of the polycrystalline silicon plate 42 of the laminate are cut into strips at intervals of 10 mm with a cutter, and one end of each strip-shaped film is cut. The polycrystalline silicon plate 42 and the surface film 3 thereon were turned up and pulled at an angle of 90 ° with respect to the substrate.
When the peel strength between No. 3 and No. 32 was measured, 5.6 k
gf / 10 mm.

Comparative Example 12 (Adhesion between PFA Film Containing No Functional Group and Polycrystalline Silicon Plate) PFA film having no functional group instead of hydroxyl group-containing PFA film (obtained in Reference Example 1) (Reference Example) Example 13 except that the product obtained in Example 3 was used.
In the same manner as in the above, a laminate including a polycrystalline silicon plate was obtained.

FIG. 19 is a schematic sectional view of the laminate obtained. When the peel strength between the polycrystalline silicon plate 42 and the surface film 33 was measured in the same manner as in Example 13, it was 1.8 k.
gf / 10 mm.

Example 14 (Durability of a laminate of a hydroxyl group-containing PFA film and a polycrystalline silicon plate) (Preparation of a sample for durability test) In the same manner as in Example 13, a surface film was cut with a cutter at intervals of 10 mm. A cut was made to reach the material to obtain a laminate, which was used as a sample for a durability test.

(Hot water resistance test) The durability test sample was immersed in 60 ° C. hot water for 24 hours.

(Methanol Dipping Test) The durability test sample was dipped in methanol at room temperature for 72 hours.

(Hydrochloric Acid Resistance Test) The durability test sample was immersed in 10% hydrochloric acid at room temperature for 24 hours.

Table 5 shows the test results.

Comparative Example 13 (Durability of laminate of PFA film containing no functional group and polycrystalline silicon plate) Example 1 was repeated except that PFA containing no functional group was used instead of PFA having a hydroxyl group.
In the same manner as in Example 4, a test sample was prepared and a durability test was performed. Table 5 shows the results.

[0242]

[Table 5]

Comparative Example 14 (Heat Resistance of Fluoropolymer Using Fluorine-Free Functional Group-Containing Monomer) The thermal decomposition temperature of the fluorinated copolymer obtained in Synthesis Example 7 was measured by TGA analysis. As a result, the temperature was 220 ° C. at a 1% thermal decomposition temperature. It was found that the fluorinated copolymer using a functional group-containing monomer having no fluorine as obtained in Synthesis Example 7 had low heat resistance. Further, Synthesis Example 7
The obtained fluoropolymer was dissolved in butyl acetate to a concentration of 10% by weight.

FIG. 20 is a schematic sectional view of the laminate test plate obtained. The butyl acetate solution of the fluorinated polymer of Synthesis Example 7 was applied on an aluminum plate 41 which had been subjected to the same pretreatment as in Example 5 by air spray so as to have a thickness of about 10 μm, and dried at 90 ° C. for 10 minutes by infrared radiation. did.

On the painted surface, the ETFE film 43 containing no functional group obtained in Reference Example 6, the polyimide film 34 for releasing (the same as in Example 9), and the aluminum plate 41 were sequentially laminated, and the temperature was set at 270 ° C. It was set in a press machine, preheated for 30 minutes, and then heated and pressed at 70 kgf / cm ² for 1 minute to obtain a laminate test plate.

After cooling, the aluminum plate 41 in contact with the polyimide film 34 and the polyimide film 34 were removed.

The obtained laminate was colored yellow-brown and PF
Foaming and peeling occurred between the A film 43 and the aluminum plate 41, and a uniform and transparent laminate was not obtained.

[0248]

According to the present invention, a solar cell material made of a fluoropolymer having excellent adhesiveness can be obtained without requiring complicated steps. Further, according to the present invention, by using the solar cell material, transparency,
A solar cell module excellent in antifouling property and weather resistance can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a basic structure of a solar cell module.

FIG. 2 is a schematic sectional view showing another basic structure of the solar cell module.

FIG. 3 is a schematic perspective view of a laminate prepared for obtaining a test piece to be subjected to a peel test in an example of the present invention.

FIG. 4 is a schematic perspective view of a test piece used for a peel test in an example of the present invention.

FIG. 5 is a schematic cross-sectional view of a laminate test plate manufactured to obtain a three-layer laminate in Example 9 of the present invention.

FIG. 6 is a schematic sectional view of a three-layer laminate obtained in Example 9 of the present invention.

FIG. 7 is a schematic sectional view of a three-layer laminate obtained in Comparative Example 7 of the present invention.

FIG. 8 is a schematic sectional view of a test piece for a tensile shear test obtained in Example 10 of the present invention.

FIG. 9 is a schematic explanatory view of an apparatus used for measuring an adhesive strength by a tensile shear method in Example 10 of the present invention.

FIG. 10 is a schematic cross-sectional view of a laminate test plate manufactured to obtain a laminate for an adhesion durability test in Example 11 of the present invention.

FIG. 11 is a schematic sectional view of a laminate for an adhesion durability test obtained in Example 11 of the present invention.

FIG. 12 shows an adhesion test (T) in Example 12 of the present invention.
FIG. 3 is a schematic cross-sectional view of a laminate test plate manufactured to obtain a laminate used for a mold release test).

FIG. 13 is a schematic sectional view of a laminate used in an adhesion test (T-peel test) obtained in Example 12 of the present invention.

FIG. 14 is a schematic sectional view of a laminate subjected to a T-peel test in Example 12 of the present invention.

FIG. 15 is a schematic sectional view of a laminate subjected to a T-peel test in Comparative Example 11 of the present invention.

FIG. 16 is a schematic cross-sectional view of a laminate test plate manufactured to obtain a laminate for an adhesion test in Example 13 of the present invention.

FIG. 17 is a schematic cross-sectional view of a laminate for an adhesiveness test obtained in Example 13 of the present invention.

FIG. 18 is a schematic sectional view of a laminate used for measurement of adhesive strength in Example 13 of the present invention.

FIG. 19 is a schematic sectional view of a laminate obtained in Comparative Example 19 of the present invention.

FIG. 20 is a schematic sectional view of a laminate test plate obtained in Comparative Example 14 of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1, 11 Insulating substrate 2, 12 Photovoltaic element 3, 13 Transparent filler layer 4, 14 Surface film 15 Back filler layer 16 Reinforcement layer 21 Metal plate 22 Spacer 23, 35 Adhesive 31 SUS plate 32 Hydroxyl group-containing PFA Film 33 PFA film containing no functional group 34 polyimide film 36 Pyrex glass plate 37 test piece 38 test jig 39 testing machine 40 glass plate 41 aluminum plate 42 polycrystalline silicon plate 43 a fluorine-free functional group-containing monomer Fluoropolymer coating used

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahiro Kumegawa 1-1, Nishiichitsuya, Settsu-shi, Osaka Daikin Industries, Ltd. Yodogawa Works (72) Inventor Noritoshi Oka 1-1-1, Nishiichitsuya, Settsu-shi, Osaka Daikin Inside Yodogawa Seisakusho Co., Ltd. (72) Inventor Hisato Masamitsu 1-1-1, Nishiichitsuya, Settsu-shi, Osaka Daikin Industrial Co., Ltd. (72) Tetsuo Shimizu 1-1-1, Nishiichitsuya Settsu-shi, Osaka, Daikin Inside Yodogawa Manufacturing Co., Ltd.

Claims (25)

[Claims] 1. A method for producing a functional group-containing fluorine-containing ethylenic monomer having at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, a carboxylate, a carboxyester group and an epoxy group. 0.05 to 30 mol% of at least one monomer and 70 to 99.95 mol% of at least one monomer of the fluorine-containing ethylenic monomer having no functional group (b) A solar cell material comprising a functional group-containing fluorine-containing ethylenic polymer obtained by copolymerization. 2. The functional group-containing fluorine-containing ethylenic monomer (a) is represented by the formula (1): CX ₂ ＣCX ¹ -R _f -Y (1) (where Y is -CH ₂ OH,- COOH, carboxylate, carboxyester group or epoxy group, X and X ¹ are the same or different, and are a hydrogen atom or a fluorine atom,
R _f is a divalent fluorinated alkylene group having 1 to 40 carbon atoms,
A fluorine-containing oxyalkylene group having 1 to 40 carbon atoms, a fluorine-containing alkylene group containing an ether group having 1 to 40 carbon atoms or a fluorine-containing oxyalkylene group containing an ether bond having 1 to 40 carbon atoms) The solar cell material according to claim 1, comprising a functional group-containing fluorine-containing ethylenic polymer, which is a kind of functional group-containing fluorine-containing ethylenic monomer. 3. The method according to claim 1, wherein the fluorine-containing ethylenic monomer having no functional group (b) is tetrafluoroethylene 85 to 9
9.7 mol% and the formula (2): CF ₂ ＣＦCF—R _f ¹ (2) (where R _f ¹ is CF ₃ or OR _f ² (R _f ² is carbon number 1 to
5 perfluoroalkyl group)
The material for a solar cell according to claim 1, comprising a functional group-containing fluorine-containing ethylenic polymer which is a mixed monomer of up to 15 mol%. 4. The fluorinated ethylenic monomer having no functional group (b) is a tetrafluoroethylene of 40 to 80.
The functional group-containing fluorine-containing ethylenic polymer according to claim 1 or 2, which is a mixed monomer of mol%, ethylene of 20 to 60 mol%, and 0 to 15 mol% of another copolymerizable monomer. Materials for solar cells. 5. The solar cell according to claim 1, wherein the fluorine-containing ethylenic monomer having no functional group (b) is a functional group-containing fluorine-containing ethylenic polymer that is vinylidene fluoride. material. 6. The functional group-containing fluorine-containing ethylenic monomer (a) in an amount of 0.01 to 30 mol% based on the total amount of the monomers.
And a mixed monomer of 70 to 99 mol% of vinylidene fluoride and 1 to 30 mol% of tetrafluoroethylene, based on the total amount of the monomers excluding the monomer (a); A mixed monomer of 50 to 99 mol% of vinylidene fluoride, 0 to 30 mol% of tetrafluoroethylene, and 1 to 20 mol% of chlorotrifluoroethylene, based on the total amount of the monomers excluding, or the monomer (a) Functional group obtained by copolymerizing 60 to 99 mol% of vinylidene fluoride, 0 to 30 mol% of tetrafluoroethylene, and 1 to 10 mol% of hexafluoropropylene with respect to the total amount of the monomers except for The solar cell material according to claim 1, comprising a fluorine-containing ethylenic polymer. 7. The fluorine-containing ethylenic monomer (b) having no functional group comprises 40 to 90 mol% of vinylidene fluoride, 0 to 30 mol% of tetrafluoroethylene and 10 to 50 mol% of hexafluoropropene. Mixed monomer, tetrafluoroethylene 40 to 70 mol%, propylene 30 to
60 mol%, other monomers copolymerizable therewith
20 mol% of a mixed monomer, or 40 to 85 mol% of tetrafluoroethylene, perfluorovinyl ether 1
The solar cell material according to claim 1, comprising a functional group-containing fluorine-containing ethylenic polymer which is a mixed monomer in an amount of 5 to 60 mol%. 8. A material for a solar cell comprising the functional group-containing fluorine-containing ethylenic polymer according to claim 1, which is in the form of a film. 9. A solar cell surface material comprising the solar cell material according to claim 1. 10. A surface film comprising the solar cell material according to claim 1. 11. A material for a transparent filler layer for a solar cell, comprising the material for a solar cell according to claim 1. Description: 12. A solar cell sealing material comprising the solar cell material according to claim 1, 2 or 7. 13. A solar cell module, wherein at least one of one or two or more coating materials disposed on the light incident side of a photovoltaic element is formed of the material according to claim 1. . 14. The solar cell according to claim 13, wherein the covering material comprises a surface film and a transparent filler layer, and at least one of the surface film and the transparent filler layer is formed of the material according to claim 1. Battery module. 15. The solar cell module according to claim 14, wherein the surface film is formed of the material according to any one of claims 1 to 6. 16. The solar cell module according to claim 14, wherein the transparent filler layer is formed of a transparent organic resin. 17. The solar cell module according to claim 16, wherein the organic resin is the material according to claim 7. 18. The solar cell module according to claim 16, wherein said organic resin is an ethylene-vinyl acetate copolymer. 19. The solar cell module according to claim 14, wherein the transparent filler layer contains a glass-based material. 20. The solar cell module according to claim 13, wherein said photovoltaic element includes a semiconductor photoactive layer or a compound semiconductor layer. 21. The solar cell module according to claim 20, wherein said semiconductor photoactive layer is a silicon-based semiconductor layer. 22. The solar cell module according to claim 21, wherein the silicon-based semiconductor layer is an amorphous silicon semiconductor layer, a single-crystal amorphous silicon semiconductor layer, or a polycrystalline amorphous silicon semiconductor layer. 23. A building material, wherein the solar cell module according to claim 13 is disposed so as to be exposed to sunlight. 24. A roofing material, wherein the solar cell module according to claim 13 is arranged so as to be exposed to sunlight. 25. A soundproof wall in which the solar cell module according to claim 13 is disposed so as to be exposed to sunlight.