KR20130118866A - Resin having improved adhesion properties, and sheet - Google Patents

Abstract

The present invention relates to an inorganic vinyl compound such as a glass plate, which is obtained by adding or applying a coupling agent to an aromatic vinyl compound-olefin copolymer such as a cross copolymer comprising an aromatic vinyl compound and an olefin, and irradiating energy such as an electron beam. The resin which has adhesiveness, or its sheet is disclosed. Such a resin or its sheet is useful, for example, as a sealing material of a photovoltaic device, a liquid crystal, an EL display, a sealing of a light emitting device, and a resin for bonding.

Description

Adhesive Improved Resin and Sheet {RESIN HAVING IMPROVED ADHESION PROPERTIES, AND SHEET}

TECHNICAL FIELD This invention relates to resin excellent in adhesiveness, such as an inorganic material, for example, a glass plate, a glass fiber, an inorganic filler, and its sheet | seat.

Background Art Conventionally, resins having excellent adhesion to inorganic materials such as glass or sheets thereof are required for applications such as photovoltaic devices (solar cells), liquid crystals, EL display members, sealing of EL light emitting devices, resins for bonding, and the like. have. However, in the conventional resin, it was not satisfactory, such as not being able to obtain sufficient adhesiveness or improving the adhesiveness at a high cost or adversely affecting other physical properties.

For example, the method (patent documents 1-4) which adds a silane coupling agent to EVA type resin and polyolefin resin, knead | mixes, crosslinks, and modifies silane is proposed. Although the adhesiveness with glass is improved by the said method, for example, the method of kneading a coupling agent with resin and carrying out radical crosslinking suppresses crosslinking at the time of sheet forming process, and makes it crosslinking reliably at sealing, The process window Was narrow, and sometimes the problem of molding process and the crosslinking defect at the time of sealing were generated. Moreover, since kneading | mixing raises cost, and also the bad influence on the physical properties, such as a crosslinking agent and a crosslinking assistant which remain, was considered, and the more efficient and stable adhesive improvement method was calculated | required.

Moreover, although patent document 5, 6, 7, 8 describes the sealing material of the photovoltaic power generation device formed by irradiating an electron beam to resin, such as EVA and a polyolefin which mix | blended a silane coupling agent and a crosslinking agent, the fault of crosslinking by a peroxide The main purpose is to adjust the molding processability by controlling the degree of crosslinking by the electron beam or by electron beam crosslinking to replace the.

On the other hand, Patent Documents 9 and 10 disclose unsaturated carboxylic acid derivatives and epoxy compounds with respect to ethylene-based resins for the purpose of improving the adhesion of the sealing material and suppressing deterioration, or modifying them using a silane coupling agent. Further coating methods are described. However, copolymerizing or modifying polar monomers such as carboxylic acid derivatives and epoxy compounds in olefinic resins has high technical difficulty and high possibility of sacrificing other physical properties.

[Patent Document 1] Korean Patent Application Publication No. 62-14111 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-214641 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-36875 [Patent Document 4] Japanese Patent Application Laid-Open No. 2007-318008 [Patent Document 5] Japanese Patent Laid-Open No. 6-334207 [Patent Document 6] Japanese Patent Application Laid-Open No. 2001-119047 [Patent Document 7] Publication No. 8-283696 [Patent Document 8] Japanese Patent Application Laid-Open No. 2009-249556 [Patent Document 9] Japanese Patent Application Laid-Open No. 2002-235047 [Patent Document 10] Japanese Patent Application Laid-Open No. 2002-235049

This invention is made | formed in view of the said situation, Comprising: It aims at providing the resin and its sheet which have the outstanding adhesiveness with an inorganic material, for example glass, etc., and can also provide adhesiveness by an efficient method.

Moreover, an object of this invention is to provide the sealing material using such a resin or a sheet, and the photovoltaic power generation device containing the said sealing material.

According to the main aspect of this invention, the resin which has adhesiveness with inorganic materials, such as glass and silicone, which is made by adding or apply | coating a coupling agent to an aromatic vinyl compound-olefin type copolymer, and irradiating energy is provided. Although the method of addition or application | coating of a coupling agent is not limited, In one Embodiment, resin formed by shape | molding an aromatic vinyl compound-olefin type copolymer to a sheet form, apply | coating a coupling agent to the surface, and irradiating an energy is provided. Moreover, in another embodiment, resin formed by adding a coupling agent to an aromatic vinyl compound-olefin type copolymer, shape | molding in a sheet form, and energy irradiation is provided.

In the above, in one embodiment, the aromatic vinyl compound is styrene, and in another embodiment, the olefin is ethylene. In another embodiment, the aromatic vinyl compound-olefin copolymer is a cross copolymer comprising an aromatic vinyl compound and an olefin. In one embodiment, such cross copolymers have an olefin-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain, wherein the content of units derived from the aromatic vinyl compound and the olefin monomer is determined by the total copolymer mass. It occupies 70 mass% or more, preferably 90 mass% or more, most preferably 95 mass% or more, and the content of the unit derived from the aromatic polyene is preferably 0.01 mass% or more, less than 5 mass% of the copolymer mass. Preferably it is 0.01 mass% or more less than 1 mass%.

Moreover, according to another embodiment, the said energy irradiation is electron beam irradiation, for example, it is generally 10keV-5000keV, Preferably it is 10keV-250keV, More preferably, it is an electron beam of the acceleration voltage of the range of 10 keV-150keV.

In another embodiment, the coupling agent is a silane coupling agent, and in particular, a silane coupling agent having a functional group of any one of an amino group, a methacryloxy group and an epoxy group.

According to the other aspect of this invention, the sheet | seat produced using the said resin, and the sealing material using such a resin or this sheet are provided, and also the photovoltaic power generation apparatus which further contains such a sealing material as a component is provided.

In this way, the aromatic vinyl compound-olefin-based copolymer is specifically selected, a coupling agent is added or applied thereto, and the energy is irradiated to obtain a resin having excellent adhesion to inorganic materials, particularly glass or silicone, or a sheet thereof. Such a resin or its sheet is useful, for example, as a sealing material of a photovoltaic device, a liquid crystal, an EL display, a sealing of a light emitting device, and a resin for bonding.

[Adhesive resin and the sheet]

This invention is excellent in adhesiveness with inorganic materials, such as a glass plate, glass fiber, and an inorganic filler, which can be obtained by adding or apply | coating a coupling agent to an aromatic vinyl compound-olefin type copolymer, and irradiating energy, Preferably, It is resin or its sheet excellent also in a filling property. The sheet in this invention contains the concept of a film, and there is no restriction | limiting in particular in the thickness, Generally, it is the range of 1 micrometer-3 mm.

In this specification, an aromatic vinyl compound-olefin type copolymer means the copolymer obtained by copolymerizing each monomer of an aromatic vinyl compound and an olefin, and content of the unit derived from these monomers is 70 mass% of the total copolymer mass. Above, Preferably it refers to the copolymer which occupies 90 mass% or more, Most preferably, 95 mass% or more. The manufacturing method of the said copolymer is arbitrary.

Examples of the aromatic vinyl compound include styrene and various substituted styrenes such as p-methyl styrene, m-methyl styrene, o-methyl styrene, ot-butyl styrene, mt-butyl styrene, pt-butyl styrene, p-chloro styrene, o-chlorostyrene, etc. are mentioned. Industrially preferably, styrene, p-methylstyrene, p-chlorostyrene, and particularly preferably styrene are used.

Examples of the olefins include ethylene and an α-olefin having 3 to 20 carbon atoms, that is, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene. In the present invention, cyclic olefins are also included in the category of olefins, and examples of the cyclic olefins include vinylcyclohexane, cyclopentene, norbornene and the like. Preferably, a mixture of ethylene or ethylene and an α-olefin, ie propylene, 1-butene, 1-hexene or 1-octene, is used, more preferably ethylene is used.

As an aromatic vinyl compound-olefin type copolymer, the copolymer of ethylene and styrene is preferable.

As a preferable embodiment of this invention, the copolymer as described in EP 0416815A2, JP 3659760, EP 872492B1 which uses the whole base material as an aromatic vinyl compound-olefin type copolymer here, respectively, is used here. It can be illustrated.

More preferably, a cross copolymer is used as an aromatic vinyl compound-olefin type copolymer. The cross copolymer is a copolymer obtained by carrying out anionic polymerization in the coexistence of an olefin-aromatic vinyl compound-aromatic polyene copolymer and an aromatic vinyl compound monomer obtained by coordination polymerization, and an olefin-aromatic vinyl compound-aromatic polyene copolymer chain. (It may be described as a main chain) and an aromatic vinyl compound polymer chain (it may be described as a side chain). The cross-copolymer and its production method are described in WO 2000-37517, USP 6559234, or WO 2007-139116, in which the entire substrate is specified and incorporated herein, respectively, from an aromatic vinyl compound and an olefin monomer. The content of units derived is at least 70 mass%, preferably at least 90 mass%, most preferably at least 95 mass% of the total copolymer mass, and the content of units derived from aromatic polyenes is preferably copolymer mass. Less than 5 mass% of 0.01 mass% or more, More preferably, it is less than 1 mass% 0.01 mass% or more. An aromatic polyene is a monomer which has carbon number of 10 or more and 30 or less, and is capable of coordination polymerization with a plurality of double bonds (vinyl groups) and a single or a plurality of aromatic groups, and one of the double bonds (vinyl groups) is used for coordination polymerization. The double bond left in the polymerized state is an aromatic polyene capable of anionic polymerization. Preferably, one or a mixture of two or more of orthodivinylbenzene, paradivinylbenzene and metadivinylbenzene is preferably used. Among the cross copolymers, most preferably, a cross copolymer in which the main chain is an ethylene-styrene-divinylbenzene copolymer chain and the side chain is a polystyrene chain is used.

Although the inorganic material which the adhesiveness of the resin or sheet which concerns on this invention becomes a problem can be illustrated with glass, a ceramic, a metal, etc., Especially preferably, it is glass. As glass, although the form of powder form, fiber form, plate form, etc. is arbitrary, Preferably it is plate-shaped glass.

In this invention, a well-known coupling agent can be used. As such a coupling agent, a silane coupling agent, a titanate coupling agent, and an isocyanate coupling agent are mentioned, Preferably a silane coupling agent is used. Such a silane coupling agent can be obtained from Shin-Etsu Chemical Co., Ltd., Dow Corning, and Evonik. A silane coupling agent is a silane compound which has a functional group and a hydrolysis-condensable group in a molecule | numerator. As a functional group, vinyl groups, such as vinyl, methacryloxy, acryloxy, and styryl, an amino group, an epoxy group, a mercapto group, a sulfide group, an isocyanate group, a halogen, etc. can be illustrated. In consideration of high adhesiveness with glass, a vinyl group, an amino group, an epoxy group, a methacryloxy group and an acryloxy group are preferable, and an amino group, a methacryloxy group, and an epoxy group are the most preferable as a functional group. You may have these functional groups in single or multiple in a molecule | numerator. These coupling agents can use 1 type (s) or 2 or more types.

As a silane coupling agent which has a vinyl group as a functional group, vinyl trimethoxysilane and vinyl triethoxysilane can be illustrated, for example. P-styryl trimethoxysilane can be illustrated as a silane coupling agent which has a styryl group as a functional group. 3-acryloxypropyl trimethoxysilane can be illustrated as a silane coupling agent which has an acryloxy group as a functional group. As a silane coupling agent which has a methacryloxy group as a functional group, 3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyl triethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxy A propylmethyl diethoxysilane can be illustrated. As a silane coupling agent which has an epoxy group as a functional group, 3-glycidoxy propyl trimethoxysilane, 3-glycidoxy propyl triethoxysilane, 3-glycidoxy propylmethyl diethoxysilane, 2- (3,4- epoxy) Cyclohexyl) ethyltrimethoxysilane can be illustrated. As a silane coupling agent which has an amino group as a functional group, 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (Aminoethyl) -3-aminopropylethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldiethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, bis (3-trimethoxysilylpropyl) amine, bis (3-triethoxy Silylpropyl) amine and N- (n-butyl) -3-aminopropyltrimethoxysilane.

Although the above is an example which has a methoxy group and an ethoxy group as a hydrolytic condensable group, a triisopropoxy group and an acetoxy group can also be used.

Although there is no restriction | limiting in particular in the usage-amount of a silane coupling agent, When adding to resin by kneading | mixing etc., it is generally used in 0.05 mass%-10 mass% with respect to resin. When applied to the resin, is generally used in a range of ^{0.1g / m 2 ~ 20 g /} m 2.

Resin concerning this invention is prepared by the method of adding or apply | coating a coupling agent to an aromatic vinyl compound-olefin type copolymer, and irradiating energy. That is, in the method of adding a coupling agent to an aromatic vinyl compound-olefin type copolymer, a coupling agent is added and knead | mixed to an aromatic vinyl compound-olefin type copolymer normally using the well-known method for adding an additive to resin. . Industrially, a twin screw extruder, a Banbury mixer, a roll molding machine, etc. can be used, for example. After doing so, it forms a sheet by well-known shaping | molding methods, such as inflation shaping | molding, extrusion shaping | molding, T die shaping | molding, calender shaping | molding, roll molding, and press molding.

On the other hand, as a method of apply | coating a coupling agent to an aromatic vinyl compound-olefin type copolymer, a coupling agent is apply | coated after first forming an aromatic vinyl compound-olefin type copolymer. The said well-known method can be used for sheet formation, and a coupling agent is apply | coated to the obtained sheet | seat using well-known coating methods, such as the gravure coating method, the roll coating method, the dip coating method, and the spraying method, for example. At this time, the coupling agent may be used after diluting in a suitable solvent or without diluting. The latter coating method can reduce the amount of the coupling agent used and is economically superior to the method of adding and kneading the former coupling agent.

Next, energy irradiation is carried out to the aromatic vinyl compound-olefin type copolymer sheet formed by adding or apply | coating a coupling agent as mentioned above. Examples of the energy irradiation used include irradiation with electron beams, gamma rays, X-rays, ultraviolet rays, neutron rays, α rays, infrared rays, visible rays, corona discharge treatments, and plasma treatments. These energy irradiation can be performed using a well-known apparatus. As a preferable embodiment of the present invention, electron beam irradiation is used. As an acceleration voltage of an electron beam, the range of 10 keV-5000 keV is generally used, and the quantity of radiation is generally 1 kGy-500 kGy. The acceleration voltage is appropriately controlled by the thickness of the sheet or the like. In this invention, although the objective of providing adhesiveness by strengthening the interaction between resin and coupling agent in the vicinity of the surface by an electron beam treatment is aimed, in order to achieve this objective, it is preferable that the acceleration voltage of an electron beam is low, Preferably it is 10 keV 250 keV, More preferably, it is 10 keV-150 keV. The interaction reinforcement referred to herein refers to reinforcement of chemical or physical interactions leading to adhesion enhancement, such as grafting, crosslinking, chemical reactions, and entanglement of molecular chains between resins and coupling agents near the surface, for example.

In addition, under certain conditions, corona discharge treatment or plasma treatment, particularly preferably corona discharge treatment, is used. Specific conditions are conditions that the coupling agent used is a silane coupling agent which preferably has an epoxy group or an amino group. Corona discharge treatment can be performed by a well-known apparatus and well-known conditions. Although a preferable corona discharge energy is not specifically limited, Preferably it is the range of 0.1-1000mJ / mm <^2> .

When such an energy irradiation is performed to the aromatic vinyl compound-olefin copolymer sheet formed by adding or applying a coupling agent, high adhesive strength can be achieved with respect to the inorganic material, for example, with respect to glass, a floating roller In the 90 ° peeling test by the method peeling test, peeling strength (adhesive strength) of 22 N / 25 mm or more, preferably 25 N / 25 mm or more can be achieved. In addition, with respect to metals such as silicon (including surface stabilized silicon), aluminum, copper, solder, and the like, peeling strength of 3 N / 6 mm or more can be achieved in the same test.

The irradiation of energy rays is similarly performed even when the coupling agent is added to the aromatic vinyl compound-olefin-based copolymer and kneaded, and when applied after sheeting. It is preferable to employ | adopt the aspect of application | coating of a coupling agent from a viewpoint of the increase of the utilization efficiency of a ring agent.

In this invention, a crosslinking adjuvant can be further added or apply | coated as needed. The crosslinking adjuvant which can be used is a well-known crosslinking adjuvant, For example, triaryl isocyanurate, triaryl cyanurate, N, N'- phenylene bismaleimide, ethylene glycol di (meth) acrylate, propanediol Di (meth) acrylate, butanediol di (meth) acrylate, hexanediol di (meth) acrylate, nonanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and the like. These crosslinking aids may be used individually by 1 type, and may be used in combination of 2 or more type. When mix | blending a crosslinking adjuvant, there is no restriction | limiting in particular in the content, Usually, it is preferable that it is the range of 0.01-5 mass% with respect to total mass.

In addition to the resin of the present invention or a sheet made of the resin, additives used for ordinary resins, for example, heat stabilizers, antioxidants, and antistatic agents, as necessary, within the range of not impairing the object of the present invention. , Fillers, colorants, lubricants, antifogging agents, foaming agents, flame retardants, flame retardant aids and the like may be added.

Since the resin of this invention or its sheet | seat is excellent in adhesiveness with inorganic materials, such as a metal for wiring, silicon | silicone, or glass, sealing of a photovoltaic device (solar cell), a liquid crystal, an EL display member, an EL light emitting device, It is useful as an adhesive resin. Hereinafter, the various sealing member of the photovoltaic device (solar cell) which is a preferable use of the resin of this invention or its sheet | seat is demonstrated in detail.

[Encapsulation material and photovoltaic power generation device]

When the adhesive resin sheet of this invention mentioned above is used as various sealing members of a photovoltaic device (solar cell), especially the sheet | seat for sealing, the preferable physical property is A hardness 50-95, and the total light transmittance is thickness It is 75% or more in 1 mm sheet. Styrene-ethylene copolymer which satisfy | fills such conditions has the composition of 5 mol% or more and 40 mol% or less of styrene content.

Moreover, for this kind of use, a cross copolymer can be used preferably. The cross-copolymer satisfying the above conditions is described in WO 2007-139116, JP-A 2009-120792, JP-A 2010-150442, for which the entire contents are incorporated herein by specifying the source, Since the preparation method, the total light transmittance, and the A hardness are described, those skilled in the art can easily prepare by making a slight trial with reference to them. Specifically, the cross-copolymer which satisfies the above conditions can be achieved by satisfying the following conditions when the aromatic vinyl compound is styrene or olefin. For example, the styrene content of the ethylene-styrene-divinylbenzene copolymer used for manufacture of a cross-copolymer is 5 mol% or more and 40 mol% or less, the divinylbenzene content is 0.01 mol% or more and 3 mol% or less, a weight average The mass ratio of the said ethylene-styrene-divinylbenzene copolymer which occupies 30,000 or more and 150,000 or less and the finally obtained cross copolymer is 40 mass% or more and 95 mass% or less, Preferably they are 40 mass% or more and 90 mass% or less. . When used as an encapsulant, significant heat resistance is required in order to stably maintain a photovoltaic cell or wiring under conditions such as being exposed to direct sunlight in summer. When encapsulation is carried out using thermoplastics without substantially crosslinking the resin, the storage elastic modulus of the resin at 120 ° C is preferably 1 × 10 ⁴ Pa or more, more preferably 1 It should be at least 10 ⁵ Pa. The said storage elastic modulus can be calculated | required simply using a well-known viscoelasticity measuring instrument. Even if the cross-copolymer is not subjected to the crosslinking treatment, it is possible to satisfy the above conditions and can be preferably used in the present invention.

Moreover, although MFR value (200 degreeC, weight 98N) of raw material resin is not specifically limited, Generally, they are 0.1g / 10min or more and 300g / 10min or less. If it is lower than this, voids are likely to occur at the time of encapsulation at the time of encapsulation, and if higher than this, there may be a fear of lack of heat resistance, that is, creep phenomenon of the solar cell or wiring under the environment. The said MFR value can be easily estimated by those skilled in the art from the well-known literature of resin to be used, and can also be adjusted by adding a small amount of oil and a plasticizer.

Moreover, as various sealing members, especially the sheet | seat for sealing of a photovoltaic device (solar cell), adhesiveness with glass is important especially from a point of ensuring reliability. In the 90 degree peeling test by a floating roller method peeling test, it is preferable to show the peeling strength (adhesive strength) of 25 N / 25mm or more.

Moreover, as a sheet | seat for sealing of a photovoltaic device (solar cell), it is preferable for sealing that a sheet | seat main body is substantially thermoplastic, and for this reason, the influence other than bridge | crosslinking by electron beam irradiation is an inorganic material, for example, glass, It is preferable to be limited to the vicinity of the sheet surface which needs adhesion. Therefore, in general, it is preferable to control the reach depth of the electrons by changing the acceleration voltage of the electron beam or to irradiate only the surface where adhesion is required. It is preferable for the sealing resin sheet for photovoltaic devices that a sheet center part or the opposite surface of an electron beam irradiation surface is not irradiated with an electron beam substantially, and is thermoplastic. As a preferable example of enhancing the interaction near the surface only, the degree of crosslinking of the whole sheet is substantially low, and in the evaluation of the gel fraction of the whole sheet, it is generally 50% or less, particularly preferably 30% or less. The gel fraction is determined by ASTMD-2765-84.

Moreover, in preferable embodiment as a sealing material of a photovoltaic device (solar cell), the light-resistant agent comprised from the ultraviolet absorber which converts light energy into harmless thermal energy, and the hindered amine-type light stabilizer which captures the radical produced by photooxidation. Compound. As a ultraviolet absorber, a benzotriazole type, a triazine type, a benzophenone type, a benzoate type, an oxalic acid anilide type, or a malonic acid ester type can be illustrated. The mass ratio of the ultraviolet absorber and the hindered amine light stabilizer is in the range of 1: 100 to 100: 1, and the total amount of the mass of the ultraviolet absorber and the hindered amine light stabilizer is the light-resistant mass, and the amount of the resin is 100 mass of resin. It is the range of 0.05-5 mass parts with respect to mass part. The above light-resistant agents can be obtained, for example, as ADEKA STAB LA series from ADEKA Co., Ltd., or as Smithson series from Smica Chemtex.

The following plasticizer and anti-aging agent can be further added as needed for the purpose of the characteristic improvement as a sealing material.

<Plasticizer>

The sealing material can mix | blend the well-known arbitrary plasticizers conventionally used for vinyl chloride and other resin. The plasticizer used preferably is an oil, an oxygen-containing, or a nitrogen-containing plasticizer, and more preferably, it is selected from paraffinic oil, naphthenic oil, ester plasticizer, epoxy plasticizer, ether plasticizer, or amide plasticizer. .

These plasticizers are comparatively good in compatibility, hard to bleed, and the plasticizing effect which can be evaluated in the grade which glass transition temperature falls is large, and can be used preferably.

The compounding quantity of a plasticizer is 1 mass part or more and 20 mass parts or less, Preferably they are 1 mass part or more and 10 mass parts or less with respect to 100 mass parts of resin of this invention or its sheet. If it is less than 1 mass part, the said effect is inadequate, and when it is higher than 20 mass parts, it may become a cause of bleeding, excessive softening, and expression of excessive adhesiveness by this. Further, by adding a plasticizer, the fluidity of the sealing material can be improved. When the MFR value of resin used especially is low, it becomes possible to adjust to a suitable MFR value as a sealing material by adding a plasticizer in said range.

<Aging agent>

Examples of suitable anti-aging agents include hindered phenolic antioxidants, phosphorus stabilizers, lactone stabilizers, vitamin E stabilizers, sulfur stabilizers and the like. The amount of use is 3 parts by mass based on 100 parts by mass of the resin composition. It is as follows.

<Film, sheet>

Although there is no restriction | limiting in particular in the thickness as a sheet | seat for sealing materials of a photovoltaic device, Generally, it is 30 micrometers-1 mm, Preferably it is 100 micrometers-0.5 mm. In order to manufacture such a resin sheet, well-known shaping | molding methods, such as inflation molding, extrusion molding, T die molding, calender molding, and roll molding, can be employ | adopted.

Moreover, it is not necessary to necessarily be a single layer as a sheet | seat for sealing materials of a photovoltaic device, Another suitable resin is used by using the adhesive resin sheet which concerns on this invention for a glass adhesive surface or the adhesive surface with cells, such as a silicon cell. The sheets may be further laminated to have a multilayer structure. Here, as another suitable resin sheet, the compounding quantity of a silane coupling agent may be small, or may be a sheet of the aromatic vinyl compound-olefin type copolymer, preferably a cross copolymer, which is not mix | blended, and another resin, for example, EVA or another ethylene Sheets of the system copolymer may also be used.

<Bridge>

In the encapsulant of the photovoltaic device made of the resin sheet of the present invention, considering the simplification of the encapsulation process and the recyclability of the photovoltaic device, the crosslinking treatment is performed to reinforce the bonding of the coupling agent and the resin sheet. Only the vicinity of the sheet surface is preferable, and the center part which occupies most of a sheet | seat or the opposite surface to the adhesive surface with glass is preferable to use it as a sealing material, without being substantially bridge | crosslinked. However, when high heat resistance is requested | required by the sheet | seat itself, or after sealing, further crosslinking process can also be performed. Generally, a crosslinking process adds a crosslinking agent and a crosslinking adjuvant to the said thermoplastic sealing material, shape | molds a film and a sheet on condition of a crosslinking temperature below, and crosslinks on predetermined crosslinking conditions after sealing of a solar cell. Thermoplasticity of the thermoplastic encapsulant of the present invention is important in the process of encapsulating a solar cell by melting and flow in the encapsulation process. Subsequent crosslinking conditions are arbitrarily determined by the crosslinking agent and crosslinking adjuvant used. The crosslinking agent and crosslinking adjuvant which can be used for the said thermoplastic sealing material are normally used for ethylene resin, styrene resin, and a styrene-ethylene copolymer, and are known. Preferable crosslinking agents, crosslinking aids, and crosslinking conditions are described, for example, in Japanese Patent Application Laid-Open No. 10-505621 (WO 96/07681), Japanese Patent Application Laid-Open No. 08-139347, and Japanese Patent Laid-Open No. 2000-183381. The encapsulation material subjected to such crosslinking treatment eliminates the merit of recycling, but does not liberate high water vapor barrier properties (low water vapor transmission rate), high volume resistivity, and corrosive substances such as acetic acid. It is advantageous in terms of improving reliability.

As a solar cell using the sealing material which concerns on this invention, the solar cell of each type of single crystal silicon type | system | group, polycrystal silicon type | system | group, amorphous silicon type | system | group, a compound type, and an organic type is illustrated. Even in a form in which a solar cell such as a thin film solar cell adheres to the surface glass and transparency is not required for the encapsulant, it does not favor high water vapor barrier properties (low water vapor transmission rate), high volume resistivity, and corrosive substances such as acetic acid. The point is advantageous in terms of improving the reliability of the solar cell.

[Example]

Hereinafter, although an Example demonstrates this invention, these Examples do not limit this invention.

<Raw material resin>

The raw material resins used in Examples and Comparative Examples are as follows.

The following cross-copolymer was manufactured by the manufacturing method of WO2000 / 37517 or WO 2007139116 which uses the whole content here, specifying the source, and the following composition was similarly calculated | required by the method of these publications. These cross-copolymers are copolymers having an ethylene-styrene-divinylbenzene copolymer chain and a polystyrene chain, which are obtained by performing anionic polymerization in the coexistence of an ethylene-styrene-divinylbenzene copolymer obtained by coordination polymerization and a styrene monomer. to be.

The styrene content, the divinylbenzene content, the weight average molecular weight (Mw), the molecular weight distribution (Mw / Mn) of the ethylene-styrene-divinylbenzene copolymer to be used, the ethylene content in the cross- -Styrene-divinylbenzene copolymer, the molecular weight (Mw) and the molecular weight distribution (Mw / Mn) of the polystyrene chain. The total styrene content is the sum of the styrene-styrene-divinylbenzene copolymer chains and polystyrene chains contained in the cross-copolymer.

[Cross Copolymer 1]

Styrene content of ethylene-styrene-divinylbenzene copolymer 15 mol%, divinylbenzene content 0.040 mol%, Mw = 70000, Mw / Mn = 2.2, content of ethylene-styrene-divinylbenzene copolymer 67 mass%, polystyrene Mw = 35000, Mw / Mn = 1.2 of chain, 60 mass% of total styrene content.

[Cross Copolymer 2]

Styrene content of ethylene-styrene-divinylbenzene copolymer 25 mol%, divinylbenzene content 0.035 mol%, Mw = 90000, Mw / Mn = 2.3, content of ethylene-styrene-divinylbenzene copolymer 67 mass%, polystyrene Mw = 44000 of the chain, Mw / Mn = 1.2, 70 mass% of total styrene content.

[Cross Copolymer 3]

Styrene content of ethylene-styrene-divinylbenzene copolymer 23 mol%, divinylbenzene content 0.035 mol%, Mw = 103000, Mw / Mn = 2.2, content of ethylene-styrene-divinylbenzene copolymer 52 mass%, polystyrene Mw = 35000, Mw / Mn = 1.2 of chain, 75 mass% of total styrene content.

[Cross Copolymer 4]

Styrene content of ethylene-styrene-divinylbenzene copolymer 24 mol%, divinylbenzene content 0.030 mol%, Mw = 115000, Mw / Mn = 2.2, content of ethylene-styrene-divinylbenzene copolymer 77 mass%, polystyrene Mw = 26000 of the chain, Mw / Mn = 1.2.

[Cross Copolymer 5]

Styrene content of ethylene-styrene-divinylbenzene copolymer 10 mol%, divinylbenzene content 0.040 mol%, Mw = 105000, Mw / Mn = 2.2, content of ethylene-styrene-divinylbenzene copolymer 85 mass%, polystyrene Mw = 22000 of the chain, Mw / Mn = 1.2.

[Ethylene-Styrene Copolymer 1]

Styrene content 41 mass% (16 mol%), Mw = 120000, Mw / Mn = 2.2.

The ethylene-styrene copolymer was prepared by the production method described in JP 3659760.

The physical properties of the used resin are summarized in Table 1.

[Table 1]

<Silane coupling agent>

The following silane coupling agent by Shin-Etsu Chemical Co., Ltd. was used.

3-aminopropyltriethoxysilane (KBE-903)

3-aminopropyltrimethoxysilane (KBM-903)

N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane (KBM-602)

3-glycidoxyoxytrimethoxysilane (KBM-403)

3-methacryloxypropyltrimethoxysilane (KBM-503)

In addition, the silane coupling agent by the following Evonik company was used.

Bis (3-trimethoxysilylpropyl) amine

<Sheet making>

The sheet | seat of thickness 0.4mm shape | molded by the heat press method (temperature 180 degreeC, time 3 minutes, the pressure 50kg / cm <^2> ) was used for the sample sheet.

<Addition, kneading method>

Using a Brabender plasticoder (PL2000 type, manufactured by Brabender), about 45 g of a total of the resin and the additives were kneaded at 180 ° C, 100 rpm, for 5 minutes to prepare a resin composition.

<Tensile test>

In accordance with JISK-6251, the obtained film is cut into No. 2 1/2 type test piece shape, and the initial tensile modulus, breaking point elongation, and breaking at a tensile rate of 500 mm / min using Shimadzu Corporation AGS-100 D type tensile tester. Intensity was measured.

<Application method>

A silane coupling agent and acetic acid were dissolved in cyclohexane to prepare a solution of 2% by mass of a coupling agent and 2% by mass of acetic acid. The cyclohexane solution was applied in the form of a sheet to a thickness of 45 microns using a bar coater. After that, it was allowed to dry naturally throughout the day.

<Electron beam irradiation>

A predetermined irradiation dose (kGy) was irradiated once with an acceleration voltage of 125 kV using an Iwasaki Electric EB apparatus TYPE: CB250 / 15 / 180L. In the case of the sheet | seat by the apply | coating method, the coating surface was irradiated.

<Compression with glass>

The surface of the glass plate of width 25mm and length 60mm was wash | cleaned with acetone, and it fully dried. The sheet was cut into a width of 25 mm and a length of 60 mm, and adhered to the glass plate so that bubbles did not enter. Thereafter, a load of 0.03 MPa was applied in the heating oven, and the mixture was crimped at 160 ° C. for 15 minutes.

<Adhesion strength measurement>

The Shimadzu Corporation AGS-100 D type tensile tester was used, and measured at a pulling rate of 100 mm / min under a 90 ° peeling condition by a floating roller method.

<Gel fraction>

According to ASTMD-2765-84, it calculated | required as follows. That is, the weighed 1.0 g polymer (size about 1 mm) was wrapped in 100 mesh stainless steel tower, and weighed. After extracting this in boiling xylene for about 5 hours, the tower was collect | recovered and dried at 90 degreeC in vacuum for 10 hours or more. After cooling sufficiently, the tower was weighed and the gel amount in the polymer was calculated by the following formula.

Gel quantity = (mass / initial polymer mass of polymer remaining in tower) * 100

&Lt; Example 1 &gt;

To 100 parts by mass of Cross-Copolymer 1, 0.1 parts by mass of Irga Knox 1076 manufactured by Chiba Japan was added as 0.2 parts by mass of weathering agent LA-52 and LA-36 manufactured by ADEKA Corporation, and antioxidant. Kneading was performed using a vendor. 0.4 mm thick sheet | seat was produced for the obtained resin kneaded material by the said hot press method.

With respect to cyclohexane, the silane coupling agent: 3-aminopropyl triethoxysilane was dissolved at the density | concentration of 2 mass% and acetic acid 2 mass%, and the solution for coating was prepared. The cyclohexane solution was applied to the production sheet using a bar coater at an opening thickness of 45.7 microns. It was then dried all day in the draft.

The electron beam irradiation of 50 kGy was performed once with the acceleration voltage of 125 kV with respect to the coupling agent application surface of the obtained sheet | seat. After a few days from the irradiation, pressing with glass was carried out in accordance with the above.

On the following day, the adhesive strength measurement was performed, but the adhesive strength was high, resulting in material destruction of the sheet. The adhesive strength measured at the time of resurfacing was 35 N / 25 mm or more.

<Examples 2-10>

In the same manner as in Example 1, however, the test was performed while changing the resin, the silane coupling agent, and the electron beam irradiation conditions of the sheet. Test conditions and results are shown in Table 2. In addition, the resin kneaded material using the cross copolymers 4 and 5 was not added the Irganox 1076 made from Chiba Japan Co., Ltd. which is an antioxidant.

<Examples 11-20>

In the same manner as in Example 1, however, when dissolving the silane coupling agent in cyclohexane, a solution for application was prepared without using acetic acid, and the resin, silane coupling agent, and electron beam irradiation conditions of the sheet were changed. The test was carried out in the same manner. When 3-methacryloxypropyl trimethoxysilane was used, 3-methacryloxypropyl trimethoxysilane was melt | dissolved in the density | concentration of 10 mass% with respect to cyclohexane, and the solution for coating was prepared. The test conditions and results are shown in Table 2.

<Comparative Examples 1-6>

In the same manner as in Example, the adhesion test with glass was carried out without irradiating the sheet with an electron beam. Test conditions and results are shown in Table 3.

<Comparative Examples 7-9>

In the same manner as in Example, except that a coupling agent was not used, the adhesion test with glass was carried out after the irradiation with the electron beam. Test conditions and results are shown in Table 3.

<Comparative Example 10-12>

In the same manner as in Example, the adhesion test with glass was conducted without using a coupling agent and irradiating an electron beam. Test conditions and results are shown in Table 3.

[Table 2]

[Table 3]

<Examples 21-25>

The adhesive strength was similarly measured after leaving the test piece obtained by carrying out similarly to Example 1, 4, 5, 7 for 1000 hours by 85 degreeC and 85% of humidity conditions with a constant temperature and humidity device. The results are shown in Table 4. In Examples 21, 23, 24, and 25 (samples identical to Examples 1, 5, 7, and 18, respectively), the adhesive strength was 35 N / 25 mm or more, and the material was broken, thereby showing substantially equivalent adhesive strength. In Example 22 (the same sample as in Example 4), the adhesive strength was 35 N / 25 mm or more and the material was broken, and the adhesive strength was increased.

[Table 4]

<Examples 26-27>

In the same manner as in Example 1, however, when dissolving the silane coupling agent in cyclohexane, a solution for coating was prepared without using acetic acid, and the resin of the sheet and the silane coupling agent were changed, and corona instead of electron beam irradiation. The test was carried out in the same manner as the discharge treatment (corona discharge energy 4 mJ / mm ² ). Test conditions and results are shown in Table 5.

[Table 5]

<Examples 28-30>

In the same manner as in Example 1, however, when dissolving the silane coupling agent in cyclohexane, a solution for coating was prepared without using acetic acid, the resin of the sheet and the silane coupling agent were changed to carry out electron beam irradiation or corona treatment. Was carried out. In the adhesion test, it pressed with the sheet | seat by the same method using the tab wire for solar cells (super soft copper flat plating wire: lead-free solder, width 6mm) instead of glass. The measurement of adhesive strength was performed on 180 degree peeling conditions. Test conditions and results are shown in Table 6.

TABLE 6

In the above result, it was confirmed that adhesiveness with glass and a metal increased remarkably by giving a coupling agent process to an aromatic vinyl compound-olefin type copolymer, and performing electron beam irradiation or corona treatment further.

Claims (13)

The resin which has adhesiveness with an inorganic material formed by adding or apply | coating a coupling agent to an aromatic vinyl compound-olefin type copolymer, and irradiating energy. The method according to claim 1,
The said aromatic vinyl compound is styrene. The method according to claim 1 or 2,
Resin wherein said olefin is ethylene. The method according to claim 1,
The aromatic vinyl compound-olefin copolymer is a cross copolymer comprising an aromatic vinyl compound and an olefin. 5. The method according to any one of claims 1 to 4,
Resin whose said energy beam is an electron beam. 6. The method according to any one of claims 1 to 5,
Resin whose said inorganic material is glass. 7. The method according to any one of claims 1 to 6,
Resin whose said coupling agent is a silane coupling agent. The method of claim 7,
The said silane coupling agent has either an amino group, an epoxy group, or a methacryloxy group. The method according to any one of claims 1 to 8,
A resin obtained by molding the aromatic vinyl compound-olefin copolymer into a sheet shape, applying a coupling agent to the surface thereof, and irradiating energy. The method according to any one of claims 1 to 8,
The resin formed by adding a coupling agent to the said aromatic vinyl compound-olefin type copolymer, shape | molding to a sheet form, and energy irradiation. The sheet formed from the resin of any one of Claims 1-10. The sealing material formed using the resin of any one of Claims 1-10, or the sheet | seat of Claim 11. The photovoltaic device comprising the encapsulant of claim 12 as a component.