CN113442538A

CN113442538A - Sheet for sealing

Info

Publication number: CN113442538A
Application number: CN202110325203.8A
Authority: CN
Inventors: 大桥贤
Original assignee: Ajinomoto Co Inc
Current assignee: Ajinomoto Co Inc
Priority date: 2020-03-27
Filing date: 2021-03-26
Publication date: 2021-09-28
Also published as: TW202146223A; JP2021154627A; KR20210120910A

Abstract

The present invention relates to a sealing sheet. The invention provides a sheet for sealing, which can form a sealing layer with excellent appearance when a device is sealed by peeling off a coating after drying without peeling off the coating. The sheet for sealing of the present invention has a layer structure in which a support, a resin composition layer, and a coating film are laminated in this order, the coating film is a polyethylene terephthalate film, and the ratio (II/I) of the haze I before heating of the coating film to the haze II after heating at 150 ℃ for 18 hours under nitrogen is less than 2.0.

Description

Sheet for sealing

Technical Field

The present invention relates to a sealing sheet, and more particularly to a sealing sheet suitable for sealing an electronic device which is resistant to moisture.

Background

Electronic devices such as organic EL devices and solar cells are extremely intolerant to moisture, and have problems such as reduced brightness and efficiency due to moisture. In order to protect these devices, sealing of the devices using a sealing sheet having a resin composition layer is performed.

Generally, the sealing sheet is composed of a support, a resin composition layer, and a coating film for protecting the resin composition layer. Since the sealing performance of the resin composition layer is lowered when moisture is mixed into the resin composition layer, it is desirable to dry the sealing sheet in advance before sealing the device. In general, it is effective to dry the resin composition layer of the sealing sheet after peeling the coating film, but a method of drying without peeling the coating film in order to prevent dust or the like from adhering to the surface of the resin composition layer during drying is also known. For example, patent document 1 discloses a method of efficiently drying with a near-infrared or mid-infrared dryer without peeling off a coating film. As the coating film, a polyethylene terephthalate (hereinafter, simply referred to as "PET") film having high heat resistance and being available at low cost is suitable.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2016/152758 pamphlet.

Disclosure of Invention

Problems to be solved by the invention

On the other hand, in electronic devices such as organic EL devices and solar cells, development of Top Emission (TE) devices and transmission type electronic devices that emit and receive light from the sealing surface side has been advanced. In TE-type and transmission-type electronic devices, since light is emitted from and received by the sealing layer surface, it is required to suppress a reduction in appearance caused by adhesion of foreign substances or the like to the sealing layer. On the other hand, the present inventors have found that when a device is sealed using a PET film as a coating film and a sealing sheet which is dried without peeling off the coating film, a large amount of foreign matter adheres to a sealing layer after peeling off the coating film, and appearance is degraded. This is presumably because oligomers precipitated from the PET film by heating in the drying step adhere to the resin composition layer, and remain in the resin composition layer even after the PET film is peeled off, causing an abnormality in the appearance of the formed sealing layer. Accordingly, an object of the present invention is to provide a sealing sheet which is excellent in the appearance of a sealing layer also in the case where the sealing sheet is dried without peeling a PET film as a coating film and the coating film is peeled thereafter to seal a device.

Means for solving the problems

As a result of intensive studies to solve the above problems, the present inventors have found that, in a sealing sheet comprising a support, a resin composition layer, and a layer formed by sequentially laminating a polyethylene terephthalate film as a coating film, a reduction in the appearance of a sealing layer can be suppressed even when the sealing sheet is dried without peeling the coating film and the coating film is peeled off thereafter to seal a device by setting the ratio of the haze of the coating film before heating to the haze after heating under a predetermined condition to a predetermined range, and have completed the present invention.

That is, the present invention has the following features.

[1] A sheet for sealing, which comprises a support, a resin composition layer, and a coating film laminated in this order, wherein the coating film is a polyethylene terephthalate film, and the ratio (II/I) of the haze I before heating of the coating film to the haze II after heating at 150 ℃ for 18 hours under nitrogen is less than 2.0.

[2] The sealing sheet according to item [ 1], wherein the resin composition layer has a total light transmittance of 90% or more.

[3] The sealing sheet according to item [ 1] or [ 2], wherein the coating film has a top coat layer on the surface on the resin composition layer side.

[4] The sealing sheet according to any one of [ 1] to [ 3 ], which is used for sealing an electronic device.

[5] The sealing sheet according to [ 4 ], wherein the electronic device is a top emission type or a transmission type electronic device.

[6] The sealing sheet according to [ 4 ] or [ 5 ], wherein the electronic device is an organic EL device or a solar cell.

[7] A method of manufacturing an electronic device having an encapsulation layer, comprising:

a step of drying the sealing sheet according to any one of [ 1] to [ 6 ],

A step of peeling off the coating film from the dried sealing sheet, and

and a step of forming a sealing layer by laminating the resin composition layer of the sealing sheet from which the coating film is peeled on the electronic component.

[8] A method for drying a sealing sheet, comprising the step of drying a sealing sheet comprising a layer in which a support, a resin composition layer, and a coating film are laminated in this order, wherein the coating film is a polyethylene terephthalate film having a ratio (II/I) of a haze I before heating to a haze II after heating at 150 ℃ for 18 hours under nitrogen of less than 2.0.

Effects of the invention

According to the present invention, a sealing sheet capable of forming a sealing layer having excellent appearance can be provided.

Detailed Description

The sheet for sealing has a layer structure in which a support, a resin composition layer, and a coating film are sequentially laminated, wherein the coating film is a polyethylene terephthalate film, and the ratio (II/I) of the haze I before heating to the haze II after heating at 150 ℃ for 18 hours under nitrogen is less than 2.0.

< laminating >

The coating film used in the sealing sheet of the present invention is a polyethylene terephthalate film.

The PET film may be subjected to a mold release treatment using a silicone resin-based mold release agent, an alkyd resin-based mold release agent, a fluororesin-based mold release agent, or the like, a matte treatment, a corona treatment, or the like. The PET film may have a multilayer structure of 2 or more layers. The thickness of the PET film is not particularly limited, but from the viewpoints of handling properties, drying of the sealing sheet, and the like, the lower limit is preferably 10 μm, more preferably 20 μm, and the upper limit is preferably 200 μm, more preferably 125 μm. Preferred ranges of thickness of the PET film (i.e., preferred combinations of upper and lower limits) are: (i) 10 to 200 μm, (ii) 20 to 200 μm, (iii) 10 to 125 μm, and (iv) 20 to 125 μm.

The coating film may have a top coat layer on the surface on the resin composition layer side in order to prevent whitening, opacification, and bright-spot defects caused by the deposition of the oligomer. Examples of the method of laminating the overcoat include Japanese patent application laid-open No. 6-328646 (laminating a laminated film layer formed by laminating a two-liquid reaction resin of a polyester compound and an isocyanate compound), Japanese patent application laid-open No. 2000-289168 (laminating a laminated film containing 10 to 100wt% of polyvinyl alcohol), Japanese patent application laid-open No. 2000-272070 (laminating a laminated film containing a polyester resin having a glass transition temperature of-20 ℃ or higher and less than 60 ℃ as a constituent component), Japanese patent application laid-open No. 2007-253511 (laminating a laminated film formed by a water-soluble acrylic resin, a polyester resin, and a crosslinking agent), and Japanese patent application laid-open No. 2010-253934 (laminating a laminated film formed by a resin composition including a cellulose derivative and a silicon oxide). The thickness of the overcoat layer is not particularly limited, but is preferably 5 to 1000nm, more preferably 10 to 500nm, and still more preferably 20 to 300nm, from the viewpoints of adhesiveness of the overcoat layer, suppression of precipitation of oligomers, and optical properties.

The haze I before heating and the haze II after heating at 150 ℃ for 18 hours under nitrogen were measured according to the methods described in the following examples. The ratio of haze I to haze II (II/I) is less than 2.0, preferably less than 1.9, more preferably less than 1.8, and still more preferably less than 1.7. The lower limit of the ratio (II/I) of the haze I to the haze II is not particularly limited, and is preferably 1.0 as the lowest value, and a lower value is more preferable. When the ratio (II/I) of the haze I to the haze II is 2.0 or more, there is a problem that an appearance abnormality (adhesion of foreign matter or the like) occurs in the sealing layer formed of the sealing sheet. For example, by laminating an overcoat layer on the coating film by the above-described method, the ratio (II/I) of the haze I to the haze II of the coating film can be made less than 2.0.

< support body >

The support used in the sealing sheet of the present invention is not particularly limited, and examples thereof include polyolefins such as polyethylene, polypropylene, polyvinyl chloride, and cycloolefin polymer, polyesters such as polyethylene terephthalate and polyethylene naphthalate, and plastic films such as polycarbonate and polyimide. As the plastic film, PET is particularly preferable. The support may be a metal foil such as an aluminum foil, a stainless steel foil, or a copper foil, or a glass substrate. From the viewpoint of drying the sealing sheet in advance before sealing the device, those having heat resistance are preferable. When the film is used as a part of a component of a device without being peeled off, the film is preferably one having high transparency. In the case of using PET, as described in the above "problem to be solved by the invention", since foreign matter precipitated from the PET film by drying adheres to the resin composition layer to degrade the appearance of the formed seal layer, the ratio (II/I) of the haze I before heating to the haze II after heating at 150 ℃ for 18 hours under nitrogen is preferably less than 2.0, as in the case of the coating film.

Glass substrates, cycloolefin polymers, polyethylene naphthalate and other plastic films having excellent heat resistance and transparency are particularly preferable.

In order to improve the moisture resistance of the sealing sheet, a plastic film having a barrier layer may be used as the support. Examples of the barrier layer include nitrides such as silicon nitride, oxides such as aluminum oxide, stainless steel foils, and metal foils such as aluminum foil. The barrier layer may have a multilayer structure of 2 or more layers. Examples of the plastic film having a barrier layer include films of polyethylene terephthalate, polyethylene naphthalate, polycarbonate, cycloolefin polymer, and the like. The plastic film may have a multilayer structure of 2 or more layers. The plastic film having a barrier layer may be a commercially available plastic film. Examples of the commercially available products include "PRIMEBARRIER" manufactured by letterpress, "べレアル" manufactured by Liguang, BARRIER film "バリアトップ 04" manufactured by Toray, "VIEW-BARRIER" manufactured by Mitsubishi chemical, X-BARRIER "," Flexent "manufactured by Konika Minidao," FIB3 "manufactured by 3M, BARRIER film manufactured by Sumitomo chemical, BARRIER film manufactured by Nikko industries, and BARRIER film manufactured by Fuji film. Further, commercially available products of the polyethylene terephthalate film with aluminum foil include, for example, "PET-added Al (1N 30)" manufactured by eastern ocean aluminum industries, and "PET-added Al 3025" manufactured by fuda metals.

For example, when the sealing sheet of the present invention is used for a display, a polarizing plate or the like may be used as a support. The support may be composed of a plurality of layers having different functions, such as a plastic film having a barrier layer and a polarizing plate. For example, a plastic film having a barrier layer and an adhesive such as an optical adhesive sheet (OCA) for a polarizing plate may be used as the support.

The support may be subjected to a mold release treatment in addition to the matting treatment and the corona treatment. That is, the support may be a releasable support. Examples of the release treatment include release treatment using a release agent such as a silicone resin-based release agent, an alkyd resin-based release agent, or a fluororesin-based release agent. In the present invention, when the support has a release layer, the release layer is also regarded as a part of the support. The thickness of the support is not particularly limited, but is preferably 10 to 200 μm, more preferably 15 to 125 μm, from the viewpoint of handling and the like.

< layer of resin composition >

The resin constituting the resin composition layer used in the sealing sheet of the present invention is not particularly limited as long as the effects of the present invention are exhibited, and examples thereof include thermosetting resins, thermoplastic resins, rubber-based resins, and the like.

Thermosetting resin

The thermosetting resin is not particularly limited, and only 1 kind may be used, or 2 or more kinds may be used in combination, and an epoxy resin is preferably used.

The epoxy resin may be used without limitation as long as it has 2 or more epoxy groups per 1 molecule on average. Examples of the epoxy resin include bisphenol a type epoxy resin, hydrogenated bisphenol a type epoxy resin, biphenyl aralkyl type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, bisphenol F type epoxy resin, phosphorus-containing epoxy resin, bisphenol S type epoxy resin, aromatic glycidyl amine type epoxy resin (e.g., tetraglycidyl diaminodiphenylmethane, triglycidyl-p-aminophenol, diglycidyl toluidine, diglycidyl aniline, etc.), alicyclic epoxy resin, aliphatic chain epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol a novolac type epoxy resin, epoxy resin having a butadiene structure, diglycidyl etherate of bisphenol, diglycidyl etherate of naphthalene diol, diglycidyl etherate of phenol, bisphenol a diglycidyl etherate of phenol, phenol type glycidyl etherate of phenol, phenol type epoxy resin, and epoxy resin, And diglycidyl etherates of alcohols, and alkyl-substituted compounds, halides, and hydrides of these epoxy resins. The epoxy resin may be used in a single amount of 1 kind, or may be used in combination of 2 or more kinds.

From the viewpoint of reactivity and the like, the epoxy equivalent of the epoxy resin is preferably 50 to 5,000, more preferably 50 to 3,000, still more preferably 80 to 2,000, and still more preferably 100 to 1,500. The "epoxy equivalent" refers to the number of grams (g/eq) of a resin containing 1 gram equivalent of epoxy groups, and is measured by a method specified in JIS K7236. The weight average molecular weight of the epoxy resin is preferably 5,000 or less.

Suitable epoxy resins include bisphenol a type epoxy resins, bisphenol F type epoxy resins, phenol novolac type epoxy resins, biphenyl aralkyl type epoxy resins, naphthalene type epoxy resins, alicyclic epoxy resins, aliphatic chain epoxy resins, and the like.

The epoxy resin may be in either a liquid state or a solid state, or a liquid epoxy resin and a solid epoxy resin may be used in combination. Herein, "liquid" and "solid" refer to the state of the epoxy resin at normal temperature (25 ℃). From the viewpoint of coatability, processability, and adhesiveness, it is preferable that at least 10% by mass or more of the entire epoxy resin used be a liquid epoxy resin. From the viewpoint of varnish viscosity, it is particularly preferable to use a liquid epoxy resin and a solid epoxy resin in combination. The mass ratio of the liquid epoxy resin to the solid epoxy resin (liquid epoxy resin: solid epoxy resin) is preferably 1:2 to 1:0, and more preferably 1:1.5 to 1: 0.1.

The content of the thermosetting resin in the resin composition is preferably 10 to 79.9% by mass, more preferably 20 to 70% by mass, and still more preferably 30 to 65% by mass, based on 100% by mass of the nonvolatile matter of the resin composition.

The content of the epoxy resin in the resin composition is preferably 10 to 79.9% by mass, more preferably 20 to 70% by mass, and still more preferably 30 to 65% by mass, based on 100% by mass of nonvolatile components in the resin composition.

Thermoplastic resin or rubber-based resin

The thermoplastic resin or the rubber-based resin may be used without particular limitation, and examples thereof include polyolefin-based resins, polyester resins, cycloolefin resins, phenoxy resins, polyvinyl acetal resins, polyimide resins, polyamideimide resins, polyethersulfone resins, polysulfone resins, and (meth) acrylic resins. Among them, polyolefin resins are preferable from the viewpoint of adhesiveness and resistance to adhesive moisture and heat. These thermoplastic resins may be used alone in 1 kind, or 2 or more kinds may be used in combination.

(polyolefin resin)

The polyolefin-based resin that can be used in the present invention is not particularly limited as long as it has a skeleton derived from an olefin monomer. Examples of the polyolefin-based resin include those described in the pamphlet of international publication No. 2017/057708 and those described in the pamphlet of international publication No. 2011/016408. The polyolefin resin is preferably a polyethylene resin, a polypropylene resin, a polybutene resin, or a polyisobutylene resin. These polyolefin resins may be homopolymers, copolymers such as random copolymers and block copolymers. Examples of the copolymer include a copolymer of 2 or more kinds of olefins and a copolymer of an olefin and a monomer other than an olefin such as a non-conjugated diene and styrene. Examples of preferable copolymers include ethylene-nonconjugated diene copolymers, ethylene-propylene-nonconjugated diene copolymers, ethylene-butene copolymers, propylene-butene-nonconjugated diene copolymers, styrene-isobutylene-styrene copolymers, and the like. As the polyolefin resin, for example, an isobutylene-modified resin described in international publication No. 2011/62167, a styrene-isobutylene-modified resin described in international publication No. 2013/108731, and the like can be preferably used.

The polyolefin resin preferably includes a polyolefin resin having an acid anhydride group (i.e., carbonyloxycarbonyl group (-CO-O-CO-)) and/or a polyolefin resin having an epoxy group, from the viewpoint of imparting excellent physical properties such as adhesiveness and resistance to moist heat of adhesion. Examples of the acid anhydride group include a group derived from succinic anhydride, a group derived from maleic anhydride, and a group derived from glutaric anhydride. The acid anhydride group may have 1 or 2 or more. The polyolefin-based resin having an acid anhydride group can be obtained by, for example, graft-modifying a polyolefin-based resin with an unsaturated compound having an acid anhydride group under radical reaction conditions. Further, the unsaturated compound having an acid anhydride group may be subjected to radical copolymerization together with an olefin or the like. Similarly, the polyolefin resin having an epoxy group can be obtained by graft-modifying a polyolefin resin with an unsaturated compound having an epoxy group such as glycidyl (meth) acrylate, 4-hydroxybutyl acrylate glycidyl ether, or allyl glycidyl ether under a radical reaction condition. In addition, an unsaturated compound having an epoxy group may be subjected to radical copolymerization together with an olefin or the like. The polyolefin resin may be used in 1 kind or 2 kinds or more, and a polyolefin resin having an acid anhydride group and a polyolefin resin having an epoxy group may be used in combination.

The concentration of the acid anhydride group in the polyolefin resin having an acid anhydride group is preferably 0.05 to 10mmol/g, more preferably 0.1 to 5 mmol/g. The concentration of the acid anhydride group is obtained from the value of the acid value defined as the mg number of potassium hydroxide required for neutralizing 1g of the acid present in the resin, in accordance with JIS K2501. The amount of the polyolefin resin having an acid anhydride group in the polyolefin resin is preferably 0 to 70% by mass, and more preferably 10 to 50% by mass.

The concentration of epoxy groups in the polyolefin resin having epoxy groups is preferably 0.05 to 10mmol/g, more preferably 0.1 to 5 mmol/g. The epoxy group concentration can be determined from the epoxy equivalent obtained in accordance with JIS K7236-1995. The amount of the polyolefin resin having an epoxy group in the polyolefin resin is preferably 0 to 70% by mass, and more preferably 10 to 50% by mass.

The polyolefin resin particularly preferably contains both a polyolefin resin having an acid anhydride group and a polyolefin resin having an epoxy group, from the viewpoint of imparting excellent physical properties such as moisture permeation resistance. Such polyolefin-based resins can form a sealant layer having excellent moisture permeation resistance and the like by reacting an acid anhydride group and an epoxy group with each other by heating to form a crosslinked structure. The crosslinked structure may be formed after sealing, but when the object to be sealed such as an organic EL device is not resistant to heat, it is desirable to seal the object using a sealing film, and the crosslinked structure is formed in advance when the sealing film is manufactured. The ratio of the polyolefin resin having an acid anhydride group and the polyolefin resin having an epoxy group is not particularly limited as long as a suitable crosslinked structure can be formed, and the molar ratio of the epoxy group to the acid anhydride group (epoxy group: acid anhydride group) is preferably 100:10 to 100:200, more preferably 100:50 to 100:150, and particularly preferably 100:90 to 100: 110.

The number average molecular weight of the polyolefin resin is not particularly limited, and is preferably 1,000,000 or less, more preferably 750,000 or less, even more preferably 500,000 or less, even more preferably 400,000 or less, even more preferably 300,000 or less, particularly preferably 200,000 or less, and most preferably 150,000 or less, from the viewpoint of providing good coatability of the varnish of the resin composition and good compatibility with other components in the resin composition. On the other hand, the number average molecular weight is preferably 1,000 or more, more preferably 3,000 or more, even more preferably 5,000 or more, even more preferably 10,000 or more, even more preferably 30,000 or more, and particularly preferably 50,000 or more, from the viewpoint of preventing shrinkage during application of the varnish of the resin composition, allowing the formed resin composition layer to exhibit moisture permeation resistance, and improving mechanical strength. The number average molecular weight in the present invention is measured by a Gel Permeation Chromatography (GPC) method (polystyrene conversion). The number average molecular weight by GPC can be specifically calculated by using LC-9A/RID-6A manufactured by Shimadzu corporation as a measuring apparatus, Shodex K-800P/K-804L/K-804L manufactured by Showa Denko K.K. K-800P/K-804L/K-804L as a column, toluene or the like as a mobile phase, at a column temperature of 40 ℃ and using a standard curve of standard polystyrene.

The polyolefin resin in the present invention is preferably amorphous from the viewpoint of suppressing the decrease in fluidity due to the thickening of the varnish. Herein, non-crystalline means that the polyolefin-based resin does not have a definite melting point, and for example, a polyolefin-based resin in which a definite peak is not observed when the melting point of the polyolefin-based resin is measured by DSC (differential scanning calorimetry) can be used.

Next, specific examples of the polyolefin-based resin will be described. Specific examples of the polyisobutylene resin include "オパノール B100" (viscosity-average molecular weight: 1,110,000) manufactured by BASF corporation and "B50 SF" (viscosity-average molecular weight: 400,000) manufactured by BASF corporation.

Specific examples of the polybutene-based resin include "HV-1900" (polybutene, number average molecular weight: 2,900) manufactured by JX エネルギー, and "HV-300M" (modified product of maleic anhydride-modified liquid polybutene ("HV-300" (number average molecular weight: 1,400)) manufactured by Toho chemical industries, a number average molecular weight of 2,100, the number of carboxyl groups constituting the acid anhydride group of 3.2/1 molecule, an acid value of 43.4mgKOH/g, and an acid anhydride group concentration of 0.77 mmol/g.

Specific examples of the styrene-isobutylene copolymer include "SIBSTAR T102" (styrene-isobutylene-styrene block copolymer, number average molecular weight: 100,000, styrene content: 30% by mass) manufactured by カネカ, and "T-YP 757B" (maleic anhydride-modified styrene-isobutylene-styrene block copolymer, acid anhydride group concentration: 0.464mmol/g, number average molecular weight: 100,000) manufactured by Star light PMC, and "T-YP 766" (glycidyl methacrylate-modified styrene-isobutylene-styrene block copolymer, epoxy group concentration: 0.638mmol/g, number average molecular weight: 100,000) manufactured by Star light PMC, and "T-YP 8920" (maleic anhydride-modified styrene-isobutylene-styrene copolymer, acid anhydride group concentration: 0.464mmol/g, epoxy group concentration, and the like, Number average molecular weight: 35,800) "T-YP 8930" by starlight PMC corporation (glycidyl methacrylate-modified styrene-isobutylene-styrene copolymer, epoxy group concentration: 0.638mmol/g, number average molecular weight: 48,700).

Specific examples of the polyethylene resin and the polypropylene resin include "EPT X-3012P" (ethylene-propylene-5-ethylidene-2-norbornene copolymer) manufactured by Mitsui chemical corporation, "EPT 1070" (ethylene-propylene-dicyclopentadiene copolymer) manufactured by Mitsui chemical corporation, and "タフマー A4085" (ethylene-butene copolymer) manufactured by Mitsui chemical corporation.

Specific examples of the propylene-butene copolymer include "T-YP 341" (glycidyl methacrylate-modified propylene-butene random copolymer, amount of butene units based on 100% by mass of the total of propylene units and butene units: 29% by mass, epoxy group concentration: 0.638mmol/g, and number average molecular weight: 155,000), "T-YP 279" (maleic anhydride-modified propylene-butene random copolymer, amount of butene units based on 100% by mass of the total of propylene units and butene units: 36% by mass, acid anhydride group concentration: 0.464mmol/g, and number average molecular weight: 35,000), "T-YP 276" (glycidyl methacrylate-modified propylene-butene random copolymer, amount of butene units based on 100% by mass of the total of propylene units and butene units: 36% by mass, "manufactured by Star light PMC, Epoxy group concentration: 0.638mmol/g, number average molecular weight: 57,000), T-YP312 (maleic anhydride-modified propylene-butene random copolymer, amount of butene units based on 100 mass% of the total of propylene units and butene units: 29 mass%, acid anhydride group concentration: 0.464mmol/g, number average molecular weight: 60,900), T-YP313 (glycidyl methacrylate-modified propylene-butene random copolymer, available from star PMC corporation, "amount of butene units based on 100 mass% of the total of propylene units and butene units: 29 mass%, epoxy group concentration: 0.638mmol/g, number average molecular weight: 155,000), and "T-YP 429" (maleic anhydride-modified ethylene-methyl methacrylate copolymer, amount of methyl methacrylate units based on 100 mass% of the total of ethylene units and methyl methacrylate units, manufactured by star PMC: 32 mass%, acid anhydride group concentration: 0.46mmol/g, number average molecular weight: 2,300), and "T-YP 430" manufactured by starlight PMC corporation (maleic anhydride-modified ethylene-methyl methacrylate copolymer, amount of methyl methacrylate units based on 100 mass% of the total of ethylene units and methyl methacrylate units: 32 mass%, acid anhydride group concentration: 1.18mmol/g, number average molecular weight: 4,500), "T-YP 431" manufactured by star PMC corporation (glycidyl methacrylate-modified ethylene-methyl methacrylate copolymer, epoxy group concentration: 0.64mmol/g, number average molecular weight: 2,400), T-YP432 (glycidyl methacrylate-modified ethylene-methyl methacrylate copolymer, epoxy group concentration: 1.63mmol/g, number average molecular weight: 3,100).

The content of the polyolefin resin in the resin composition of the present invention is not particularly limited. However, from the viewpoint of providing good coatability and compatibility and ensuring good moisture-heat resistance and workability (inhibition of tackiness), the content is preferably 80% by mass or less, more preferably 75% by mass or less, still more preferably 70% by mass or less, further preferably 60% by mass or less, further more preferably 55% by mass or less, and particularly preferably 50% by mass or less, relative to 100% by mass of the nonvolatile component of the resin composition. On the other hand, from the viewpoint of improving moisture permeation resistance and improving transparency, the content is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, further preferably 7% by mass or more, further more preferably 10% by mass or more, particularly preferably 35% by mass or more, and most preferably 40% by mass or more, relative to 100% by mass of the nonvolatile component of the resin composition.

Adhesion-imparting agent

The resin composition of the present invention may further contain an adhesion-imparting agent for the purpose of further improving adhesiveness. The adhesion imparting agent is also referred to as a tackifier, and examples thereof include terpene-based resins, rosin-based resins, alicyclic hydrocarbon-based resins, aliphatic/aromatic copolymer-based hydrocarbon resins, aromatic hydrocarbon-based resins, coumarone-type resins, and the like. The adhesion-imparting agent may be used in combination of 2 or more. More preferable examples of the adhesion imparting agent include aliphatic/aromatic copolymerized hydrocarbon resins, aromatic hydrocarbon resins, and coumarone/indene resins.

The content of the adhesion-imparting agent in the resin composition of the present invention is preferably 5 to 75% by mass, more preferably 6 to 69% by mass, and still more preferably 8 to 63% by mass, based on 100% by mass of the nonvolatile component of the resin composition.

Examples of commercially available adhesion imparting agents include Arkon P-90, Arkon P-100, Arkon P-115, Arkon P-125 (saturated hydrocarbon Resin containing a cyclohexane ring), Pine Crystal ME-G, Pine Crystal ME-H, T-REZ RB093, T-REZ RC115, Neoplaster L90, Neoplaster 120, Neoplaster 140, T-REZ HA-105, Petco 120, Petrtac 90HS, Petrotac 100V, Novalues C9, Novalues L, Nitto Resin L-5, Nitto Resin V-120S, Nitto Resin G-90, all available from Mitsuba chemical industries, and the like.

Hygroscopic filler

The resin composition of the present invention may further contain a hygroscopic filler. Examples of the hygroscopic filler include metal oxides and metal hydroxides. Examples of the metal oxide include calcium oxide, magnesium oxide, strontium oxide, aluminum oxide, barium oxide, calcined hydrotalcite, calcined dolomite, and the like. Examples of the metal hydroxide include calcium hydroxide, magnesium hydroxide, strontium hydroxide, aluminum hydroxide, barium hydroxide, and half-burned hydrotalcite. As the hygroscopic filler, those surface-treated with a surface treatment agent can be used. Examples of the surface treatment agent used for the surface treatment include higher fatty acids, alkylsilanes, and silane coupling agents.

The content of the hygroscopic filler in the resin composition is not particularly limited, and is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 20% by mass or more, particularly preferably 25% by mass or more, preferably 80% by mass or less, more preferably 75% by mass or less, further preferably 70% by mass or less, and for example, may be 65% by mass or less and 60% by mass or less, based on 100% by mass of the nonvolatile content of the resin composition.

Curing agent and/or curing accelerator

The resin composition of the present invention may further contain a curing agent and/or a curing accelerator. The curing agent and/or curing accelerator may be used alone in 1 kind, or may be used in combination with 2 or more kinds. Examples of the curing agent include imidazole compounds, tertiary and quaternary amine compounds, dimethylurea compounds, organic phosphine compounds, primary and secondary amine compounds, and the like. Examples of the curing accelerator include imidazole compounds, tertiary or quaternary amine compounds, dimethylurea compounds, and organic phosphine compounds.

The content of the curing agent and/or the curing accelerator in the resin composition is not particularly limited, but is preferably 5% by mass or less, more preferably 1% by mass or less, and further preferably 0.0005% by mass or more, more preferably 0.001% by mass or more, based on 100% by mass of the nonvolatile component of the resin composition.

Other ingredients

The resin composition of the present invention may further contain other additives different from the above-mentioned components within a range not impairing the effects thereof. Examples of such additives include inorganic fillers such as silica, alumina, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, boron nitride, aluminum borate, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, and calcium zirconate; organic fillers such as rubber particles, silicon powder, nylon powder, and fluorine powder; thickeners such as Orben, Benton, and the like; silicone, fluorine, or polymer defoaming or leveling agents; and adhesion-imparting agents such as triazole compounds, thiazole compounds, triazine compounds, and porphyrin compounds.

Since it is necessary to efficiently emit or receive light from the sealing surface side, the total light transmittance of the resin composition layer is preferably 90% or more, more preferably 92% or more, and still more preferably 95% or more. The total light transmittance may be determined according to, for example, JIS K7361-1 "test method for total light transmittance of plastic-transparent material part 1: single beam method ".

< method for producing resin composition >

The method for producing the resin composition of the present invention is not particularly limited, and examples thereof include a method of adding compounding ingredients and, if necessary, a solvent, and mixing them using a kneading roll, a rotary mixer, and the like.

< sheet for sealing >

For example, the sealing sheet can be obtained by applying the resin composition of the present invention prepared in the form of varnish by blending an organic solvent to a support, drying the obtained coating film by heating or blowing hot air, etc., to form a resin composition layer on the support, and further laminating a coating film on the resin composition layer. Alternatively, the sealing sheet is also obtained by applying the resin composition of the present invention prepared in the form of varnish by blending an organic solvent to a coating film, drying the resulting coating film by heating or blowing hot air, etc., to form a resin composition layer on the coating film, and further laminating a support on the resin composition layer.

< use >)

The sealing sheet of the present invention is used as a sealing member for electronic devices such as organic EL devices (top emission type and transmission type organic EL devices, etc.) and solar cells (dye-sensitized solar cells, organic thin-film solar cells, perovskite type solar cells, etc.).

Method for manufacturing electronic device having sealing layer

The method for manufacturing an electronic device having a sealing layer of the present invention includes: the sealing sheet of the present invention is dried, the coating film is peeled off from the dried sealing sheet, and the resin composition layer of the sealing sheet from which the coating film is peeled off is laminated on an electronic component to form a sealing layer.

(drying step of sealing sheet)

The sealing sheet of the present invention is dried. The drying method is not particularly limited, and examples thereof include convection heat transfer drying, conduction heat transfer drying, radiation heat transfer drying, microwave drying, drying with hot air, drying with irradiation of near infrared rays or mid infrared rays, and the like. The method of drying the sealing sheet is not particularly limited, and examples thereof include a method of putting a drying rack provided with the sealing sheet into a drying furnace and heating the drying rack, a method of putting the drying rack into the drying furnace and then heating the drying rack in vacuum, and a method of putting the drying rack provided with the sealing sheet into a drying furnace of a conveying system and heating the drying rack. The following describes, as examples, conductive heat transfer drying, drying by hot air, and drying by irradiation with near infrared rays or mid-infrared rays.

Conductive heat transfer drying may use a ceramic heating plate or the like. Drying by conductive heat transfer drying is preferably performed under a dry air or dry inert gas atmosphere. Examples of the inert gas include nitrogen, argon, helium, neon, and the like. The amount of water vapor contained in the air or the inert gas is preferably 0 to 500ppm (i.e., 0 to 500. mu. mol/mol), more preferably 0 to 250ppm, further preferably 0 to 100ppm, further preferably 0 to 50ppm, and particularly preferably 0 to 30 ppm.

In order to avoid adverse effects on the resin composition layer and to efficiently dry the resin composition layer, the drying temperature is preferably 60 to 180 ℃, more preferably 60 to 170 ℃, even more preferably 60 to 160 ℃, even more preferably 80 to 150 ℃, even more preferably 90 to 150 ℃, and the drying time is preferably 0.5 to 300 minutes, even more preferably 1 to 240 minutes, even more preferably 5 to 180 minutes, even more preferably 10 to 180 minutes. Herein, the drying temperature means a surface temperature of the coating film on the resin composition layer, which can be measured by mounting a surface contact type K thermocouple on the coating film. The drying time means a time during which the surface temperature of the coating film reaches a predetermined drying temperature.

In the case of conveying and installing the sealing sheet in the conductive heat transfer drying apparatus, the sealing sheet may be conveyed to the drying apparatus in a state of being fixed to a glass substrate or the like, and dried, in order to prevent the sealing sheet from being bent or the like.

For drying, a commercially available conduction heat transfer drying apparatus may be used. Examples of a commercially available conduction and heat transfer drying device include a ceramic heating plate manufactured by アズワン.

For drying with hot air, a hot air circulation oven or the like can be used. The drying with hot air is preferably performed under a dry air or dry inert gas atmosphere. Examples of the inert gas include nitrogen, argon, helium, neon, and the like. The amount of water vapor contained in the air or the inert gas is preferably 0 to 500ppm (i.e., 0 to 500. mu. mol/mol), more preferably 0 to 250ppm, further preferably 0 to 100ppm, further preferably 0 to 50ppm, and particularly preferably 0 to 30 ppm.

When the sealing sheet is conveyed and installed in a drying device using hot air, the sealing sheet may be conveyed to the drying device in a state of being fixed to a glass substrate or the like, and dried, in order to prevent the sealing sheet from being bent or the like.

For drying, a commercially available drying device using hot air may be used. Examples of commercially available drying devices using hot air include a hot air circulation dryer manufactured by Iskawa corporation.

For drying by irradiation with near infrared rays or mid infrared rays, a near infrared ray or mid infrared ray dryer may be used. The near infrared ray or middle infrared ray dryer means a dryer which irradiates near infrared ray or middle infrared ray. Examples of the filament (heat source) used as the light source (heater) of the near-infrared or mid-infrared dryer include tungsten, nichrome, carbon, KANTHAL (registered trademark), and the like, and tungsten and KANTHAL are preferable, and tungsten is particularly preferable. In order to dry the resin composition layer efficiently, a near infrared ray or a mid infrared ray dryer having an irradiation peak wavelength in the range of 1.0 to 4.0 μm is preferably used. The peak wavelength is more preferably in the range of 1.0 to 3.5. mu.m, still more preferably 1.25 to 3.5. mu.m, and yet more preferably 1.5 to 3.5. mu.m. In the present specification, the near infrared or mid infrared region means a range of wavelengths of 0.78 to 4.0 μm, the near infrared region means a range of 0.78 μm or more and less than 2.0 μm, and the mid infrared region means a range of 2.0 μm or more and 4.0 μm or less. In this specification, near infrared rays or mid infrared rays are sometimes simply referred to as infrared rays, and near infrared rays or mid infrared rays dryers are sometimes simply referred to as infrared dryers.

The drying by means of a near-infrared or mid-infrared dryer is preferably carried out under a dry air or dry inert gas atmosphere. Examples of the inert gas include nitrogen, argon, helium, neon, and the like. The amount of water vapor contained in the air or the inert gas is preferably 0 to 500ppm (i.e., 0 to 500. mu. mol/mol), more preferably 0 to 250ppm, further preferably 0 to 100ppm, further preferably 0 to 50ppm, and particularly preferably 0 to 30 ppm.

The infrared ray is preferably irradiated from the coating film side to the sealing sheet. In order to dry the sealing sheet efficiently, the distance between the light source (heater) of the near infrared or mid-infrared dryer and the sealing sheet is preferably 5 to 100cm, more preferably 10 to 50cm, and even more preferably 10 to 30cm, and the irradiation angle of the infrared rays is preferably 0 to 80 degrees, more preferably 0 to 70 degrees, and even more preferably 0 to 60 degrees.

In order to prevent the sealing sheet from being bent or the like when the sheet is conveyed to the infrared dryer, the sealing sheet may be conveyed to the infrared dryer in a state of being fixed to a glass substrate or the like, and dried.

For drying, a commercially available near infrared or mid infrared dryer may be used. Examples of commercially available near-infrared or mid-infrared dryers include, for example, a near-infrared wavelength control system manufactured by japan.

(peeling step of coating film)

The coating film is peeled off from the sealing sheet dried by the above (drying step of the sealing sheet).

The step of peeling the coating film from the sealing sheet is preferably performed in a dry air or dry inert gas atmosphere. Examples of the inert gas include nitrogen, argon, helium, neon, and the like. The amount of water vapor contained in the air or the inert gas is preferably 0 to 500ppm (i.e., 0 to 500. mu. mol/mol), more preferably 0 to 250ppm, further preferably 0 to 100ppm, further preferably 0 to 50ppm, and particularly preferably 0 to 30 ppm.

(step of Forming sealing layer)

The sealing layer is formed by laminating the resin composition layer of the sealing sheet from which the coating film has been peeled off (coating film peeling step) on an electronic component.

In order to prevent the resin composition layer of the sealing sheet after drying from adsorbing moisture or the like, sealing is preferably performed under an inert gas atmosphere or under vacuum. Examples of the inert gas include nitrogen, argon, helium, neon, and the like. The ambient pressure (pressure of inert gas) when sealing is performed under an inert gas atmosphere is preferably 1X 10⁵Pa or so. The pressure (reduced pressure) around the sealing member is preferably 1 to 1X 10³Pa, more preferably 1 to 1X 10²Pa。

The apparatus used for lamination is not particularly limited, and known apparatuses such as a roll laminator, a press (プレス), and the like can be used. Further, a plurality of apparatuses such as a roll laminator and a punch press can be used in combination.

[ roll laminator ]

When the roll laminator is used, the roll speed is preferably 10 to 1500 mm/min, more preferably 100 to 500 mm/min, in order to achieve good adhesion of the resin composition layer to the support.

In order to avoid damage to the electronic device, the roll pressure of the roll laminator is preferably 0 to 0.5MPa, and more preferably 0 to 0.3 MPa. Herein, roll pressing means a pressurizing force generated by an air gun (エアシリンジ), expressed as gauge pressure (original pressure). Further, the rolling to 0 means that the pressing force is 0. When the roll pressure is 0, it is preferable that the laminate is laminated by a roll laminator and then pressed by a press machine to be described later.

The roll temperature of the roll laminator is preferably 30 to 120 ℃, more preferably 40 to 110 ℃, and further preferably 50 to 100 ℃ in order to soften the resin composition layer and improve the followability to the substrate. Herein, the roll temperature means a temperature of a roll surface in which a heater is built in the roll and is digitally controlled, and can be measured by a surface contact type K thermocouple.

For lamination, a commercially available roll laminator can be used. Examples of commercially available roll LAMINATORs include "LPD 2325" manufactured by FUJIPLA, "roll LAMINATOR VA 770H" manufactured by Dacheng LAMINATOR, "roll LAMINATOR VA 700", "roll LAMINATOR VAII-700", and "Mach 630 up" manufactured by Bondon. Examples of the material of the roller laminator include stainless steel, rubber, and the like, and silicone rubber is preferable.

[ punching machine ]

When a press machine is used, the press pressure is preferably 0.01 to 0.5MPa, more preferably 0.01 to 0.3MPa, in order to prevent cracks in the electronic device due to the pressure. Herein, the pressing pressure of the pressing machine means a pressure applied to the pressed body (i.e., a pressure applied to the surface of the sealing sheet) by the vacuum cylinder or load control.

The press temperature of the press is preferably 30 to 120 ℃, more preferably 40 to 120 ℃, further preferably 50 to 110 ℃, further preferably 60 to 100 ℃, and the press time is preferably 20 to 450 seconds, more preferably 60 to 300 seconds. Herein, the press temperature of the press machine means a temperature of a surface of a press portion (for example, a flat plate such as a metal plate) of the press machine in which a cartridge heater is built in the surface and digitally controlled, and can be measured by a surface contact type K thermocouple.

For lamination, a commercially available punch press may be used. Examples of commercially available press machines include "batch vacuum press CVP-300" manufactured by MORTON corporation; a vacuum press machine "VHI-2051" manufactured by Beichuan Kogyo Co. Examples of the material of the flat plate for pressing include stainless steel, alloys of iron, and the like, and stainless steel is preferable.

[ curing of the resin composition layer ]

When a thermosetting sealing sheet is used, the laminate of the sealing sheet and the substrate is heated to form a cured resin composition layer (i.e., a sealing layer). Curing can be carried out using, for example, a hot air circulation oven, an infrared heater, a hot air gun, a high-frequency induction heating device, a hot plate, or the like. When the hot stamping is performed using a stamping press for lamination, the lamination and the curing of the resin composition layer may be performed simultaneously. The curing temperature varies depending on the resin composition layer and the support, but is preferably 80 to 120 ℃, more preferably 80 to 110 ℃, and the curing time is preferably 10 to 120 minutes, more preferably 10 to 60 minutes. The thickness of the cured resin composition layer is preferably 3 to 200 μm, more preferably 5 to 150 μm, and still more preferably 10 to 100 μm.

When a pressure-sensitive adhesive sealing sheet is used, the resin composition layer is cured by heating the sealing sheet before the sealing sheet is laminated on the substrate. However, after the sealing sheet and the substrate are laminated, they may be further heated. When the pressure-sensitive adhesive type sealing sheet is laminated and then heated, the heating temperature is preferably 50 to 150 ℃, more preferably 60 to 100 ℃, and still more preferably 60 to 90 ℃ in order to avoid thermal deterioration of the electronic device.

< method for drying sealing sheet of the present invention >

The method for drying a sealing sheet of the present invention includes a step of drying a sealing sheet comprising a layer in which a support, a resin composition layer, and a coating film are sequentially laminated, the coating film being a polyethylene terephthalate film having a ratio (II/I) of a haze I before heating to a haze II after heating at 150 ℃ for 18 hours under nitrogen of less than 2.0.

The coating film is as described in < coating film > of the sealing sheet of the present invention. The drying step is as described above in the method for manufacturing an electronic device having a sealing layer according to the present invention (drying step of a sealing sheet).

< electronic device >

The electronic device in which the sealed portion is sealed with the sealing sheet of the present invention can be manufactured by, for example, laminating the sealing sheet of the present invention on the sealed portion in the electronic device.

[ examples ]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the examples below, and may be modified as appropriate within the scope that can be adapted to the gist described above and below, and all of them are included in the technical scope of the present invention.

< membrane >

Details of the coating used in the following examples and comparative examples are shown in table 1 below. The coating film was entirely a PET film subjected to a release treatment with a silicone resin-based release agent. As the film C, a film in which an organic film is laminated on the film B as an overcoat layer is used. The surfaces of the films C and D on the side of the organic overcoat layer were subjected to a mold release treatment.

[ Table 1]

Film coating	Manufacturer of the product	Coated substrate	Film thickness	Outer coating
					Film A	Prince F-TEX	PET film	25μm	-
Film B	Toyo CLOTH	PET film	38μm	-
					Film C	Toyo CLOTH	PET film	38μm	Presence of an organic overcoat
Film D	Prince F-TEX	PET film	50μm	Presence of an organic overcoat

< production of varnish of resin composition >

Preparation example: production of clear olefin resin composition

A mixture was prepared by dispersing 35 parts by mass of a maleic anhydride-modified liquid polyisobutylene ("HV-300M" manufactured by Toho chemical industry Co., Ltd.), 60 parts by mass of a polybutene ("HV-1900" manufactured by JX エネルギー Co., Ltd.), and 100 parts by mass of a half-burned hydrotalcite in 130 parts by mass of a 60 mass% Swasol solution of a saturated hydrocarbon resin having a cyclohexane ring (Arkon P-125 "manufactured by Mikan chemical Co., Ltd.) using a three-roll mill. To the obtained mixture, 200 parts by mass of a 20 mass% Swasol solution of a glycidyl methacrylate-modified polypropylene-polybutene copolymer ("T-YP 341" manufactured by Star photo PMC Co.), 0.5 part by mass of an amine-based curing accelerator (2, 4, 6-tris (dimethylaminomethyl) phenol) and 16 parts by mass of toluene were mixed, and the obtained mixture was uniformly dispersed by a high-speed rotary mixer to obtain an olefin-based resin composition varnish.

< production of sheet for sealing >

Example 1: the olefin-based resin composition varnish obtained in the production example was uniformly applied to the surface of the film C subjected to the mold release treatment by a die coater, and heated at 130 ℃ for 30 minutes, thereby obtaining a sheet having a resin composition layer with a thickness of 20 μm. Then, thin glass plate (OA-10G, 50 μm, manufactured by Nippon electric glass Co., Ltd.) as a support was laminated on the resin composition layer of the obtained sheet to obtain a sealing sheet.

Example 2: a sealing sheet was produced in the same manner as in example 1, except that the film D was used as a coating film instead of the film C.

Comparative examples 1 and 2: a sealing sheet (thickness of the resin composition layer: 20 μm) was produced in the same manner as in example 1, except that the films A and B were used as the coating films, respectively, instead of the film C.

< method of measurement >

(1) Measurement of haze of coating film

The haze of films A, B, C and D described in table 1 was measured as follows. First, the film was cut into 50mm × 50mm to prepare a test piece. The haze I of the initial coating was measured using a haze meter (HZ-V3, manufactured by SUGA TEST MACHINE) in accordance with JIS K7136. Subsequently, the film subjected to the measurement was dried by heating at 150 ℃ for 18 hours in a nitrogen oven, and the surface opposite to the surface subjected to the mold release treatment was wiped for cleaning to measure the haze II of the film after heating in the same manner.

The ratio of the initial haze I measured as described above to the haze II after heating (i.e., II/I, hereinafter sometimes referred to as "haze ratio") was calculated, and the coating was evaluated by the following criteria.

(reference of haze ratio)

Good (good): haze ratio of less than 2.0

X (bad): the haze ratio is 2.0 or more.

(2) Evaluation of appearance of sealing layer

The substrates as the sealed portions were sealed using the sealing sheets prepared in examples and comparative examples, and the appearance when the sealing layer was formed was evaluated as follows. First, the sealing sheet was heated at 150 ℃ for 1 hour under a nitrogen atmosphere without peeling off the coating film, and the resin composition layer was dried. Subsequently, the coating film was peeled off, and the resultant was bonded to a top-emission anode substrate (ITO/Ag alloy film/ITO, anode composition, manufactured by Toyobo industries Co., Ltd.) at 80 ℃ using a roll laminator. After the bonding, the number of foreign matter adhering to the anode substrate on which the sealing layer was formed was measured at a magnification of 200 times from a sheet glass as a support using a digital microscope (VHS-5000, manufactured by KEYENCE corporation), and the appearance of the sealing layer was evaluated according to the following criteria.

(Standard of appearance)

Good (good): per 500 μm × 500 μm, the number of foreign substances adhered is less than 100

X (bad): the number of foreign substances adhered per 500. mu. m.times.500. mu.m is 100 or more.

The evaluation results are shown in the following table.

[ Table 2]

From the evaluation results, it was found that when a PET film having a haze ratio of less than 2.0 was used as a sealing sheet for a coating film, the number of foreign matters adhering to the anode substrate on which the sealing layer was formed was less than 100, and a sealing layer having excellent appearance was able to be formed.

Sealing of top emission organic EL device Using sealing sheet of example 1

A top emission type organic EL device was prepared as follows. First, an organic material was formed as a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer on a substrate made by intee corporation by vacuum evaporation. Next, an inorganic material was formed into a film as an electron injection layer and a cathode by vacuum deposition. As the cathode, a co-evaporated material of Mg and Ag was used. Next, the sealing sheet of example 1 was dried at 150 ℃ under a nitrogen atmosphere for 3 hours without peeling off the coating film. The dried sealing sheet was peeled off, and the resulting laminate was bonded to a device at 80 ℃ using a roll laminator so that the resin composition layer was on the lower side. After the bonding, the number of foreign matter adhering was observed from the thin glass plate as a support by using a digital microscope, and as a result, the number was less than 100, and it was confirmed that the appearance was excellent.

Industrial applicability

The sealing sheet of the present invention is dried without peeling off the coating film as the polyethylene terephthalate film, and can prevent dust and the like from adhering to the surface of the resin composition layer during drying, and can suppress the generation of foreign matter in the coating film during drying. Therefore, the sheet can be suitably used as a sealing sheet for electronic devices which do not resist moisture and require high appearance for a sealing layer. The sealing sheet of the present invention is particularly useful as a sealing sheet for electronic devices such as organic EL devices (top emission type and transmission type organic EL devices, etc.) and solar cells (dye-sensitized solar cells, organic thin-film solar cells, perovskite type solar cells, etc.).

Claims

1. A sheet for sealing, which comprises a support, a resin composition layer, and a coating film laminated in this order, wherein the coating film is a polyethylene terephthalate film, and the ratio (II/I) of the haze I before heating of the coating film to the haze II after heating at 150 ℃ for 18 hours under nitrogen is less than 2.0.

2. The sealing sheet according to claim 1, wherein the resin composition layer has a total light transmittance of 90% or more.

3. The sealing sheet according to claim 1 or 2, wherein the coating film has a top coat layer on the surface on the resin composition layer side.

4. The sealing sheet according to any one of claims 1 to 3, which is used for sealing an electronic device.

5. The sealing sheet according to claim 4, wherein the electronic device is a top emission type or a transmission type electronic device.

6. The sealing sheet according to claim 4 or 5, wherein the electronic device is an organic EL device or a solar cell.

7. A method of manufacturing an electronic device having an encapsulation layer, comprising:

a step of drying the sealing sheet according to any one of claims 1 to 6,

A step of peeling off the coating film from the dried sealing sheet, and

8. A method for drying a sealing sheet, comprising the step of drying a sealing sheet comprising a layer in which a support, a resin composition layer, and a coating film are laminated in this order, wherein the coating film is a polyethylene terephthalate film having a ratio (II/I) of a haze I before heating to a haze II after heating at 150 ℃ for 18 hours under nitrogen of less than 2.0.