JP7138407B2 - Adhesive composition, adhesive sheet, and sealing body - Google Patents

Description

The present invention provides an adhesive composition that is easily molded into a sheet shape and that does not easily corrode electrode members, organic semiconductors, etc. when used as a sealing material, and an electrode member formed using this adhesive composition. The present invention relates to an adhesive sheet having an adhesive layer that does not easily corrode organic semiconductors, etc., and a sealing body obtained by sealing an object to be sealed with the adhesive sheet.

In recent years, organic EL elements have attracted attention as light-emitting elements capable of high-luminance light emission by low-voltage direct-current driving.
However, the organic EL element has a problem that the luminescence characteristics such as luminance, luminous efficiency, and luminous uniformity tend to deteriorate over time.
As a cause of the problem of deterioration in light emission characteristics, it is thought that oxygen, moisture, etc. enter the interior of the organic EL element and deteriorate the electrodes and organic layers. and to prevent the ingress of oxygen and moisture.
As a method for forming such a sealing material, a method using a thermosetting resin sheet is known.

For example, Patent Document 1 discloses (A) a polyisobutylene resin, (B) a polyisoprene resin and/or polyisobutylene resin having a functional group capable of reacting with an epoxy group, (C) a tackifying resin, and (D) an epoxy resin. A resin composition containing a resin, a resin composition sheet containing the resin composition, and the like are described.
Patent Document 1 also describes that the resin composition can be easily formed into a sheet, and that the obtained resin composition sheet is suitably used for encapsulating an organic EL element.

WO2011/062167 (US2012/0283375 A1)

Patent Literature 1 describes that the use of a tackifying resin improves the adhesiveness of the resin composition.
Furthermore, according to the study of the present inventors, it was also found that a resin composition containing a tackifying resin having a relatively high softening point is suitable as a raw material for an adhesive sheet because of its excellent shape retention.
However, in spite of such advantages, it has been found that when the organic EL element is sealed with a resin composition containing a tackifying resin, the organic EL element is easily deteriorated and dark spots are likely to occur.

As a result of further studies by the present inventors, it was conceived that one of the causes of the deterioration of the organic EL element is that the antioxidant corrodes the electrode member, the organic semiconductor, and the like. Since antioxidants are usually added to commercially available tackifying resins, sealing organic EL elements with a resin composition obtained by blending a tackifying resin deteriorates the organic EL elements. I found it easier.
The present invention has been made in view of the above circumstances, and provides an adhesive composition that is easy to mold into a sheet shape and that does not easily corrode electrode members, organic semiconductors, etc. when used as a sealing material. To provide an adhesive sheet having an adhesive layer which is formed using a composition and which hardly corrodes electrode members, organic semiconductors, etc., and a sealing body obtained by sealing an object to be sealed with the adhesive sheet. aim.

The present inventors have made intensive studies to solve the above problems, and found that an adhesive composition containing a modified polyolefin resin, a polyfunctional epoxy compound that is liquid at 25°C, and a polyfunctional epoxy compound that is solid at 25°C. The inventors have found that the product can be easily formed into a sheet without using a tackifying resin and have excellent sealing performance, and have completed the present invention.

Thus, according to the present invention, the following adhesive compositions (1) to (9), adhesive sheets (10) to (12), and sealing bodies (13) and (14) are provided.
(1) An adhesive composition containing the following components (A), (B), and (C), wherein the volatile components contained in the adhesive composition are analyzed by the purge and trap method described below. The content of the volatile antioxidant, converted to toluene, is 0.2 mg/cm ³ or less when the adhesive composition is mixed.
(A) component: modified polyolefin resin (B) component: polyfunctional epoxy compound that is liquid at 25°C (C) component: polyfunctional epoxy compound that is solid at 25°C [purge & trap method]
An adhesive layer (18 mm × 18 mm × 12 µm) formed using the adhesive composition was placed in a glass tube, heated at 120°C for 20 minutes in a helium stream, and gas released from the adhesive layer was collected. Collect continuously in tubes. The collected gas is then introduced into a gas chromatography-mass spectrometer and analyzed for volatile components contained in the adhesive composition. At this time, the amount of the volatile antioxidant is quantified from a calibration curve prepared using toluene.

(2) The adhesive composition according to (1), wherein the component (A) is an acid-modified polyolefin resin.
(3) The adhesive composition according to (1) or (2), wherein the total amount of component (B) and component (C) is 100 to 200 parts by mass per 100 parts by mass of component (A). thing.
(4) The content ratio (mass ratio) of the component (B) and the component (C) is [component (B): component (C)] = 100:1 to 1:1, (1) to (3) ).
(5) The adhesive composition according to any one of (1) to (4), further comprising component (D) below.
Component (D): imidazole-based curing catalyst (6) The content of component (D) is 1 to 10 parts by mass per 100 parts by mass of the total amount of component (B) and component (C), ( The adhesive composition according to 5).
(7) The adhesive composition according to any one of (1) to (6), further comprising component (E) below.
(E) component: silane coupling agent

(8) The adhesive composition according to (7), wherein the content of component (E) is 0.01 to 10 parts by mass per 100 parts by mass of component (A).
(9) The adhesive composition according to any one of (1) to (8), wherein the volatile antioxidant is a hindered phenol antioxidant.
(10) An adhesive sheet having an adhesive layer, wherein the adhesive layer is formed using the adhesive composition according to any one of (1) to (9).
(11) The adhesive sheet according to (10), wherein the adhesive layer has a thickness of 5 to 25 μm.
(12) The adhesive sheet according to (10) or (11), further comprising a release film.
(13) A sealed body in which an object to be sealed is sealed using the adhesive sheet according to any one of (10) to (12).
(14) The sealing body according to (13), wherein the object to be sealed is an organic EL element, an organic EL display element, a liquid crystal display element, or a solar cell element.

According to the present invention, an adhesive composition that is easy to mold into a sheet shape and that does not easily corrode electrode members, organic semiconductor materials, etc. when used as a sealing material, is formed using this adhesive composition. , an adhesive sheet having an adhesive layer that does not easily corrode electrode members, organic semiconductors, and the like, and a sealing body obtained by sealing an object to be sealed with the adhesive sheet.

Hereinafter, the present invention will be described in detail by dividing into 1) adhesive composition, 2) adhesive sheet, and 3) encapsulant.

1) Adhesive Composition The adhesive composition of the present invention is an adhesive composition containing the following components (A), (B), and (C), and is subjected to the following purge and trap method. The content of the volatile antioxidant is 0.2 mg/cm ³ or less in terms of toluene when the volatile components contained in the adhesive composition are analyzed.
(A) component: modified polyolefin resin (B) component: polyfunctional epoxy compound that is liquid at 25°C (C) component: polyfunctional epoxy compound that is solid at 25°C

[Purge & Trap Method]
An adhesive layer (18 mm × 18 mm × 12 µm) formed using the adhesive composition was placed in a glass tube, heated at 120°C for 20 minutes in a helium stream, and gas released from the adhesive layer was collected. Collect continuously in tubes. The collected gas is then introduced into a gas chromatography-mass spectrometer and analyzed for volatile components contained in the adhesive composition. At this time, the amount of the volatile antioxidant is quantified from a calibration curve prepared using toluene.

(A) Component: Modified Polyolefin Resin The adhesive composition of the present invention contains a modified polyolefin resin as the (A) component.
Since the adhesive composition of the present invention contains a modified polyolefin resin, it has excellent adhesive strength. Also, by using an adhesive composition containing a modified polyolefin resin, a relatively thin adhesive layer can be efficiently formed.

The modified polyolefin resin is a polyolefin resin into which a functional group is introduced, which is obtained by modifying a polyolefin resin as a precursor using a modifying agent.

A polyolefin resin refers to a polymer containing a repeating unit derived from an olefinic monomer. The polyolefin resin may be a polymer consisting only of repeating units derived from an olefinic monomer, or may be a polymer comprising repeating units derived from an olefinic monomer and a monomer copolymerizable with the olefinic monomer. It may be a polymer consisting of a repeating unit of

The olefinic monomer is preferably an α-olefin having 2 to 8 carbon atoms, more preferably ethylene, propylene, 1-butene, isobutylene, or 1-hexene, and still more preferably ethylene or propylene. These olefinic monomers may be used singly or in combination of two or more.
Examples of monomers copolymerizable with olefinic monomers include vinyl acetate, (meth)acrylic acid esters, and styrene. These monomers copolymerizable with the olefinic monomer can be used singly or in combination of two or more.

Polyolefin resins include very low density polyethylene (VLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene, polypropylene (PP), ethylene-propylene co- Polymers, olefin elastomers (TPO), ethylene-vinyl acetate copolymers (EVA), ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester copolymers, and the like.

Modifiers used for modification treatment of polyolefin resins are compounds having functional groups in their molecules.
Functional groups include carboxyl group, carboxylic acid anhydride group, carboxylic acid ester group, hydroxyl group, epoxy group, amide group, ammonium group, nitrile group, amino group, imide group, isocyanate group, acetyl group, thiol group, ether group. , a thioether group, a sulfone group, a phosphonic group, a nitro group, a urethane group, a halogen atom, and the like. Among these, a carboxyl group, a carboxylic anhydride group, a carboxylic acid ester group, a hydroxyl group, an ammonium group, an amino group, an imide group, and an isocyanate group are preferred, and a carboxylic anhydride group and an alkoxysilyl group are more preferred. are particularly preferred.
A compound having a functional group may have two or more functional groups in the molecule.

Modified polyolefin resins include acid-modified polyolefin resins and silane-modified polyolefin resins. Acid-modified polyolefin-based resins are preferred from the standpoint of obtaining more excellent effects of the present invention.

Acid-modified polyolefin resin refers to a polyolefin resin graft-modified with an acid. For example, a polyolefin resin is reacted with an unsaturated carboxylic acid or an unsaturated carboxylic acid anhydride (hereinafter sometimes referred to as "unsaturated carboxylic acid, etc.") to introduce a carboxyl group or the like (graft modification). mentioned.

Examples of unsaturated carboxylic acids to be reacted with the polyolefin resin include unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, tetrahydrophthalic acid, and aconitic acid; maleic anhydride, itaconic anhydride, unsaturated carboxylic anhydrides such as glutaconic anhydride, citraconic anhydride, aconitic anhydride, norbornenedicarboxylic anhydride, and tetrahydrophthalic anhydride;
These can be used individually by 1 type or in combination of 2 or more types. Among these, maleic anhydride is preferable because it is easy to obtain an adhesive composition having excellent adhesive strength.

The amount of the unsaturated carboxylic acid or the like to be reacted with the polyolefin resin is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 3 parts by mass, still more preferably 0.2 parts by mass, based on 100 parts by mass of the polyolefin resin. ~1.0 part by mass. The adhesive composition containing the acid-modified polyolefin resin obtained in this manner is superior in adhesive strength.

Commercially available products can also be used as the acid-modified polyolefin resin. Examples of commercially available products include ADMER (registered trademark) (manufactured by Mitsui Chemicals, Inc.), Unistol (registered trademark) (manufactured by Mitsui Chemicals, Inc.), BondyRam (manufactured by Polyram), orevac (registered trademark) (manufactured by ARKEMA), Modic (registered trademark) (manufactured by Mitsubishi Chemical Corporation) and the like.

The silane-modified polyolefin resin is a polyolefin resin graft-modified with an unsaturated silane compound. The silane-modified polyolefin resin has a structure in which an unsaturated silane compound, which is a side chain, is graft-copolymerized with a polyolefin resin, which is a main chain. Examples thereof include silane-modified polyethylene resins and silane-modified ethylene-vinyl acetate copolymers, and silane-modified polyethylene resins such as silane-modified low density polyethylene, silane-modified ultra-low density polyethylene, and silane-modified linear low density polyethylene are preferred.

As the unsaturated silane compound to be reacted with the polyolefin resin, a vinylsilane compound is preferable. silane, vinyltriphenoxysilane, vinyltribenzyloxysilane, vinyltrimethylenedioxysilane, vinyltriethylenedioxysilane, vinylpropionyloxysilane, vinyltriacetoxysilane, vinyltricarboxysilane, and the like. These can be used individually by 1 type or in combination of 2 or more types.
As for the conditions for graft polymerization of the unsaturated silane compound to the main chain polyolefin resin, a conventional graft polymerization method may be adopted.

The amount of the unsaturated silane compound to be reacted with the polyolefin resin is preferably 0.1 to 10 parts by mass, particularly preferably 0.3 to 7 parts by mass, based on 100 parts by mass of the polyolefin resin. Further, it is preferably 0.5 to 5 parts by mass. When the amount of the unsaturated silane compound to be reacted is within the above range, the obtained adhesive composition containing the silane-modified polyolefin resin has excellent adhesive strength.

A commercially available product can also be used as the silane-modified polyolefin resin. Commercially available products include, for example, Linklon (registered trademark) (manufactured by Mitsubishi Chemical Corporation). Among them, low-density polyethylene-based Linklon, linear low-density polyethylene-based Linklon, ultra-low-density polyethylene-based Linklon, and ethylene-vinyl acetate copolymer-based Linklon can be preferably used.

Modified polyolefin-based resins may be used singly or in combination of two or more.

The number average molecular weight (Mn) of the modified polyolefin resin is preferably 10,000 to 2,000,000, more preferably 20,000 to 1,500,000.
The number average molecular weight (Mn) of the modified polyolefin resin can be obtained as a standard polystyrene conversion value by performing gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

(B) Component: Polyfunctional Epoxy Compound Liquid at 25°C The adhesive composition of the present invention contains a polyfunctional epoxy compound that is liquid at 25°C as component (B).
"A polyfunctional epoxy compound that is liquid at 25°C" refers to a polyfunctional epoxy compound that has a fixed volume at 25°C (excluding the volatilized portion) but does not have a fixed shape. The viscosity at 25° C. of the “polyfunctional epoxy compound that is liquid at 25° C.” used in the present invention is usually 0.1 to 100,000 mPa s, preferably 0.2 to 50,000 mPa s, more preferably 0.3 to 10,000 mPa·s.
Since the adhesive composition of the present invention contains the component (B), it has excellent fluidity when heated. Therefore, by using the adhesive composition of the present invention, it is possible to efficiently form an adhesive layer having good conformability to irregularities.

A polyfunctional epoxy compound means a compound having two or more epoxy groups in the molecule.

Component (B) includes bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, hydrogenated bisphenol S type epoxy resin, and the like. mentioned.
The (B) component polyfunctional epoxy compounds may be used singly or in combination of two or more.
The molecular weight of the (B) component polyfunctional epoxy compound is preferably 700 to 5,000, more preferably 1,400 to 4,500.
By using an adhesive composition containing the component (B) having a molecular weight of 700 or more, it becomes easier to obtain a sealing material with lower outgassing properties. On the other hand, since an adhesive composition containing component (B) having a molecular weight of 5,000 or less is superior in fluidity, the use of such an adhesive composition facilitates the formation of an adhesive layer that is superior in conformability to irregularities. Become.

The epoxy equivalent of the (B) component polyfunctional epoxy compound is preferably 100 g/eq to 500 g/eq, more preferably 150 g/eq to 300 g/eq. By using an adhesive composition in which the polyfunctional epoxy compound of component (B) has an epoxy equivalent of 100 g/eq or more and 500 g/eq or less, it is possible to efficiently form a sealing material having high adhesive strength and excellent curability. can.

(C) Component: Polyfunctional Epoxy Compound Solid at 25°C The adhesive composition of the present invention contains a polyfunctional epoxy compound that is solid at 25°C as component (C).
"A polyfunctional epoxy compound that is solid at 25°C" is a polyfunctional epoxy resin that has a softening point in a temperature range of 25°C or higher.
By containing the component (C), the adhesive composition of the present invention is less likely to become liquid and easily maintains a constant shape, and thus can be easily molded into a sheet.

Component (C) includes bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, hydrogenated bisphenol S type epoxy resin, and the like. mentioned.
The (C) component polyfunctional epoxy compounds may be used singly or in combination of two or more.
The molecular weight of the (C) component polyfunctional epoxy compound is preferably 500 to 10,000, more preferably 1,000 to 5,000.

In the adhesive composition of the present invention, the total amount of components (B) and (C) is preferably 100 to 200 parts by mass, more preferably 120 to 170 parts by mass, per 100 parts by mass of component (A). part by mass.
When the content of components (A) to (C) satisfies the above requirements, the adhesive composition has appropriate fluidity and can easily maintain a constant shape.

The content ratio (mass ratio) of component (B) and component (C) is preferably [component (B): component (C)] = 100:1 to 1:1, preferably 10:1 to 2:1. is more preferable.
As the amount of component (B) relative to component (C) increases, the adhesive composition becomes more fluid when heated.
On the other hand, as the amount of component (C) relative to component (B) increases, the adhesive composition tends to maintain a constant shape.

As will be described later, the adhesive composition of the present invention has an extremely low content of volatile antioxidants. Since commercially available tackifiers usually contain an antioxidant, the adhesive composition of the present invention preferably does not contain a tackifier.
However, the tackifier has the effect of increasing the adhesiveness of the adhesive composition and the effect of maintaining the shape of the adhesive composition. easily inferior.
Therefore, component (C) is an essential component in the adhesive composition of the present invention. By using the component (C), an adhesive composition with better adhesion can be obtained. In addition, by using component (B) and component (C) together and adjusting their proportions, the fluidity of the adhesive composition can be moderated, so that an adhesive layer of a certain shape can be formed. becomes easier.

The adhesive composition of the present invention may contain components other than the components (A), (B) and (C).
Components other than the components (A), (B), and (C) include the following components (D) and (E).
(D) component: imidazole-based curing catalyst (E) component: silane coupling agent

(D) Component: Imidazole Curing Catalyst Imidazole curing catalysts include 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, and 2-phenyl. -4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole and the like. Among these, 2-ethyl-4-methylimidazole is preferred.
These imidazole-based curing catalysts can be used singly or in combination of two or more.

By using an adhesive composition containing an imidazole-based curing catalyst, it becomes easier to obtain a cured product having excellent adhesiveness even at high temperatures.

When the adhesive composition of the present invention contains component (D), its content is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the total amount of components (B) and (C). More preferably, it is 2 to 5 parts by mass. A cured product of an adhesive composition having an imidazole-based curing catalyst content within this range exhibits excellent adhesiveness even at high temperatures.

(E) Component: Silane Coupling Agent As the silane coupling agent, a known silane coupling agent can be used. Among them, organosilicon compounds having at least one alkoxysilyl group in the molecule are preferred.
Silane coupling agents include polymerizable unsaturated group-containing silicon compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane; 3-glycidoxypropyltrimethoxysilane, 8-glycidoxyoctyl Silicon compounds having an epoxy structure such as trimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxy Amino group-containing silicon compounds such as silane, N-(2-aminoethyl)-8-aminooctyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane; 3-chloropropyltrimethoxysilane 3-isocyanatopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-trimethoxysilylpropylsuccinic anhydride; and the like.
These silane coupling agents can be used singly or in combination of two or more.

By using an adhesive composition containing a silane coupling agent, it becomes easier to obtain a cured product having excellent adhesive strength under normal temperature and high temperature environments.

When the adhesive composition of the present invention contains a silane coupling agent, the content thereof is preferably 0.01 to 10 parts by mass, more preferably 0.02 parts by mass, per 100 parts by mass of component (A). ~5 parts by mass.

The adhesive composition of the invention may contain a solvent.
Examples of solvents include aromatic hydrocarbon solvents such as benzene and toluene; ester solvents such as ethyl acetate and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as heptane; alicyclic hydrocarbon solvents such as cyclopentane, cyclohexane, and methylcyclohexane; and the like.
These solvents can be used singly or in combination of two or more.
The content of the solvent can be appropriately determined in consideration of coatability and the like.

The adhesive composition of the present invention may contain other components as long as the effects of the present invention are not impaired.
Other components include additives such as UV absorbers, antistatic agents, light stabilizers, antioxidants, resin stabilizers, fillers, pigments, extenders and softeners.
These can be used individually by 1 type or in combination of 2 or more types.
When the adhesive composition of the present invention contains these additives, the content thereof can be appropriately determined according to the purpose.

The adhesive composition of the present invention can be prepared by appropriately mixing and stirring predetermined components according to a conventional method.

When the adhesive composition of the present invention was analyzed for volatile components contained in the adhesive composition by the following purge and trap method, the content of the volatile antioxidant was 0.00 in terms of toluene. It is characterized by being 2 mg/cm ³ or less.
An "antioxidant" is an antioxidant substance added to inhibit oxidation of the components in the resin composition. Examples of antioxidants include phenol antioxidants, phosphorus antioxidants, sulfur antioxidants, amine antioxidants, and the like. "Volatile antioxidant" is, among antioxidants, when it is contained in the adhesive layer, when the adhesive layer is heated to 120 ° C. in an inert gas (such as helium) stream Second, it is an antioxidant having a property of being released as a volatile component from the adhesive layer.
Such volatile antioxidants are not particularly limited, but include, for example, hindered phenol-based antioxidants.

[Purge & Trap Method]
An adhesive layer (18 mm × 18 mm × 12 µm) formed using the adhesive composition was placed in a glass tube, heated at 120°C for 20 minutes in a helium stream, and gas released from the adhesive layer was collected. Collect continuously in tubes. The collected gas is then introduced into a gas chromatography-mass spectrometer and analyzed for volatile components contained in the adhesive composition. At this time, the amount of the volatile antioxidant is quantified from a calibration curve prepared using toluene.

When a commercial product is used as a raw material for preparing an adhesive composition, and the commercial product contains an antioxidant, the resulting adhesive composition will contain an antioxidant. .
Therefore, when producing the adhesive composition of the present invention, it is important to use production raw materials that do not contain any antioxidant or that contain a very small amount of antioxidant.
As described above, commercially available tackifiers usually contain antioxidants, so in the adhesive composition of the present invention, no tackifier is used, and instead the component (B) and ( It is preferable to improve adhesiveness and shape retention by using component C in combination.

Since the adhesive composition of the present invention contains an extremely small amount of volatile antioxidant, it hardly corrodes electrode members, organic semiconductors, etc. when used as a sealing material. Therefore, the adhesive composition of the present invention is suitably used when forming a sealing material.

2) Adhesive Sheet The adhesive sheet of the present invention is an adhesive sheet having an adhesive layer, and the adhesive layer is formed using the adhesive composition of the present invention.

Although the thickness of the adhesive layer of the adhesive sheet is not particularly limited, it is preferably 5 to 25 μm, more preferably 10 to 20 μm.
An adhesive layer having a thickness within the above range is suitably used as a sealing material.

The adhesive sheet of the present invention may have a release film.
The release film functions as a support during the manufacturing process of the adhesive sheet and as a protective sheet for the adhesive layer until the adhesive sheet is used.
When using the adhesive sheet of the present invention, the release film is usually peeled off.

As the release film, a conventionally known one can be used. For example, there is a substrate for a release film having a release layer treated with a release agent on the substrate.
Examples of substrates for release films include paper substrates such as glassine paper, coated paper, and fine paper; laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper substrates; polyethylene terephthalate resin, polybutylene terephthalate resin, plastic films such as polyethylene naphthalate resin, polypropylene resin, polyethylene resin; and the like.
Examples of release agents include rubber-based elastomers such as silicone-based resins, olefin-based resins, isoprene-based resins and butadiene-based resins, long-chain alkyl-based resins, alkyd-based resins, fluorine-based resins, and the like.

When the adhesive sheet of the present invention has a release film, the number of release films may be one or two, but usually one on each side of the adhesive layer, two in total. of release film. At this time, the two release films may be the same or different, but the two release films preferably have different release strengths. Since the peel strengths of the two peel films are different, problems are less likely to occur when using the adhesive sheet. That is, by making the peeling forces of the two peeling films different, the step of peeling the peeling films first can be performed more efficiently.

The manufacturing method of the adhesive sheet is not particularly limited. For example, a casting method can be used to manufacture the adhesive sheet.
When the adhesive sheet is produced by a casting method, the adhesive composition of the present invention is applied to the release-treated surface of the release film using a known method, and the resulting coating film is dried to obtain a release film-attached film. An adhesive sheet can be obtained by manufacturing an adhesive layer and then laminating another release film on the adhesive layer.

Examples of methods for applying the adhesive composition include spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, gravure coating and the like.
Drying conditions for drying the coating film include, for example, 80 to 150° C. for 30 seconds to 5 minutes.

The adhesive layer of the adhesive sheet of the present invention has thermosetting properties.
Conditions for thermosetting the adhesive layer are not particularly limited.
The heating temperature is usually 80-200°C, preferably 90-150°C.
The heating time is usually 30 minutes to 12 hours, preferably 1 to 6 hours.

The peeling adhesive strength of the adhesive layer after curing treatment at 23° C. is usually 1 to 100 N/25 mm, preferably 10 to 50 N/25 mm, and the peeling adhesive strength at 85° C. is usually 1 to 100 N. /25mm, preferably 5 to 50N/25mm.
The peeling adhesive strength at 23°C is based on JIS Z0237: 2009, under the conditions of a temperature of 23°C and a relative humidity of 50% and a temperature of 85°C (no humidity control), and a peel angle of 180°. A peel test can be performed and measured.
The water vapor transmission rate of the adhesive layer after curing is usually 0.1 to 200 g·m ^-2 ·day ^-1 , preferably 1 to 150 g·m ^-2 ·day ^-1 .
The water vapor transmission rate can be measured using a known water vapor transmission rate measuring device.

As described above, the adhesive layer of the adhesive sheet of the present invention is less likely to corrode electrode members, organic semiconductors, and the like. Therefore, by using the adhesive sheet of the present invention, it is possible to extend the life of the organic EL element and the like.

3) Sealing body The sealing body of the present invention is obtained by sealing an object to be sealed using the adhesive sheet of the present invention.
The sealing body of the present invention includes, for example, a substrate, an element (object to be sealed) formed on the substrate, and a sealing material for sealing the element, The encapsulant is derived from the adhesive layer of the adhesive sheet of the present invention (hardened adhesive layer).

The substrate is not particularly limited, and various substrate materials can be used. In particular, it is preferable to use a substrate material having a high visible light transmittance. Further, it is preferable to use a material that has a high barrier performance to block moisture and gas that try to enter from the outside of the element, and that is excellent in solvent resistance and weather resistance. Specifically, transparent inorganic materials such as quartz and glass; Transparent plastics such as polystyrenes, polyarylates, polysulfones, polyolefins, etc., and the aforementioned gas barrier films;
The thickness of the substrate is not particularly limited, and can be appropriately selected in consideration of the light transmittance and the ability to block the inside and outside of the device.

Objects to be sealed include organic EL elements, organic EL display elements, liquid crystal display elements, solar cell elements, and the like.

The method for manufacturing the sealed body of the present invention is not particularly limited. For example, after the adhesive layer of the adhesive sheet of the present invention is placed on the object to be sealed, the adhesive layer of the adhesive sheet and the object to be sealed are adhered by heating.
By then curing this adhesive layer, the sealing body of the present invention can be produced.

Adhesion conditions for adhering the adhesive layer of the adhesive sheet and the object to be sealed are not particularly limited. The bonding temperature is, for example, 23-100°C, preferably 40-80°C. This adhesion treatment may be performed while applying pressure.
As the curing conditions for curing the adhesive layer, the conditions described above can be used.

The sealed body of the present invention is obtained by sealing an object to be sealed with the adhesive sheet of the present invention.
Therefore, in the sealed body of the present invention, the performance of the sealed object is maintained for a long period of time.

EXAMPLES The present invention will be described in more detail below with reference to examples. However, the present invention is by no means limited to the following examples.
Parts and % in each example are based on mass unless otherwise specified.

[Example 1]
Acid-modified polyolefin resin (acid-modified α-olefin polymer, manufactured by Mitsui Chemicals, trade name: UNISTOL H-200, number average molecular weight: 47,000) 100 parts, polyfunctional epoxy compound (1) (hydrogenated bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation, trade name: YX8000, liquid at 25 ° C., epoxy equivalent: 205 g / eq, viscosity at 25 ° C.: 1900 mPa s) 100 parts, polyfunctional epoxy compound (2) (hydrogenated bisphenol A-type epoxy resin, manufactured by Mitsubishi Chemical Corporation, trade name: YX8040, solid at 25 ° C., epoxy equivalent: 1100 g / eq, softening point: 84 ° C.) 25 parts, imidazole-based curing catalyst (manufactured by Shikoku Kasei Co., Ltd., trade name: Curesol 2E4MZ, 2-ethyl-4-methylimidazole) and 0.1 part of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM4803) are dissolved in methyl ethyl ketone to form an adhesive with a solid concentration of 25%. Composition 1 was prepared.
This adhesive composition 1 was applied on the release-treated surface of a release film (manufactured by Lintec, trade name: SP-PET382150), and the resulting coating film was dried at 100 ° C. for 2 minutes to give an adhesive with a thickness of 12 μm. An adhesive layer was formed, and the release-treated surface of another release film (trade name: SP-PET381031, manufactured by Lintec Corporation) was adhered thereon to obtain an adhesive sheet 1.

[Example 2]
Adhesive composition 2 was prepared in the same manner as in Example 1, except that the amount of polyfunctional epoxy compound (2) was changed to 50 parts, and adhesive sheet 2 was obtained using this. rice field.

[Example 3]
In Example 1, polyfunctional epoxy compound (3) (hydrogenated bisphenol A epoxy resin, manufactured by Mitsubishi Chemical Corporation, trade name: YX8034, liquid at 25° C., epoxy equivalent: Adhesive Composition 3 was prepared and Adhesive Sheet 3 was obtained in the same manner as in Example 1, except for using 270 g/eq, viscosity at 25° C.: 9000 mPa·s).

[Comparative Example 1]
Acid-modified polyolefin resin (α-olefin polymer, manufactured by Mitsui Chemicals, Inc., trade name: UNISTOL H-200, number average molecular weight: 47,000) 100 parts, polyfunctional epoxy compound (1) (hydrogenated bisphenol A type Epoxy resin, manufactured by Mitsubishi Chemical Corporation, trade name: YX8000, liquid at 25 ° C.) 100 parts, tackifier (styrene-based monomer aliphatic monomer copolymer, softening point 95 ° C., manufactured by Mitsui Chemicals, trade name: FTR6100 ) 50 parts, an imidazole-based curing catalyst (manufactured by Shikoku Kasei Co., Ltd., trade name: Cursol 2E4MZ, 2-ethyl-4-methylimidazole) 1 part, and a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM6803) 0.1 part was dissolved in methyl ethyl ketone to prepare adhesive composition 4 having a solid concentration of 30%.
Adhesive sheet 4 was obtained in the same manner as in Example 1, except that adhesive composition 4 was used.

[Comparative Example 2]
In Comparative Example 1, polyfunctional epoxy compound (3) (hydrogenated bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation, trade name: YX8034, liquid at 25° C.) was used instead of polyfunctional epoxy compound (1). Adhesive Composition 5 was prepared in the same manner as in Comparative Example 1, except for the above, and Adhesive Sheet 5 was obtained using this.

The adhesive sheets 1-5 obtained in Examples 1-3 and Comparative Examples 1-2 were analyzed as follows.
[Analysis of outgassing]
One release film of the adhesive sheet obtained in Examples or Comparative Examples was peeled off, the adhesive sheet was placed on a glass plate so that the exposed adhesive layer faces the glass plate, and the adhesive sheet was heated at 23°C using a heat laminator. Glued.
Next, the remaining release film was peeled off and used as a measurement sample, outgassing was generated under conditions of 120° C. for 20 minutes, and the generated amount was quantified.
The amount of outgassing was quantified using a gas chromatograph mass spectrometer (GCMS-QP2010, manufactured by Shimadzu Corporation) using a column of 5%-Diphenyl-95% Dimethyl polysiloxane (HP-5ms). At this time, a calibration curve was created using toluene.
The detected amount of outgassing (amount of outgassing (mg) per 1 ^cm3 of adhesive sheet) and the amount of volatile antioxidant (di-t-butylhydroxytoluene) contained therein (amount per 1 ^cm3 of adhesive sheet ( mg)) are shown in Table 1.

Table 1 shows the following.
Di-t-butylhydroxytoluene was not detected in the adhesive sheets of Examples 1-3. On the other hand, in Comparative Examples 1 and 2, di-t-butylhydroxytoluene was detected.
As described above, the adhesive sheets of Examples 1 to 3 hardly contain a compound that can corrode the electrode member or the organic semiconductor. and organic semiconductors.

Claims (11)

The object to be sealed is a sealed body obtained by sealing using the following adhesive sheet 1 ,
A sealing body, wherein the object to be sealed is an organic EL element, an organic EL display element, a liquid crystal display element, or a solar cell element.
[Adhesive sheet 1]
An adhesive sheet having an adhesive layer, wherein the adhesive layer is formed using the following adhesive composition 2.
[Adhesive composition 2]
When an adhesive composition containing the following components (A), (B), and (C) is analyzed for volatile components contained in the adhesive composition by the following purge and trap method: and a volatile antioxidant content of 0.2 mg/cm ³ or less in terms of toluene.
(A) component: modified polyolefin resin
Component (B): Polyfunctional epoxy compound that is liquid at 25°C
Component (C): a polyfunctional epoxy compound that is solid at 25°C
[Purge & Trap Method]
An adhesive layer (18 mm × 18 mm × 12 µm) formed using the adhesive composition was placed in a glass tube, heated at 120°C for 20 minutes in a helium stream, and gas released from the adhesive layer was collected. Collect continuously in tubes. The collected gas is then introduced into a gas chromatography mass spectrometer and analyzed for volatile components contained in the adhesive composition. At this time, the amount of the volatile antioxidant is quantified from a calibration curve prepared using toluene. The sealing body according to claim 1, wherein the component (A) is an acid-modified polyolefin resin. 3. The encapsulant according to claim 1, wherein the total amount of said components (B) and (C) is 100 to 200 parts by mass per 100 parts by mass of said (A) component. Any one of claims 1 to 3, wherein the content ratio (mass ratio) of the component (B) and the component (C) is [component (B): component (C)] = 100:1 to 1:1. Encapsulant as described. The sealing body according to any one of claims 1 to 4, wherein the adhesive composition 2 further contains the following component (D).
(D) component: imidazole-based curing catalyst 6. The sealing body according to claim 5, wherein the content of component (D) is 1 to 10 parts by mass per 100 parts by mass of the total amount of components (B) and (C). The sealing body according to any one of claims 1 to 6, wherein the adhesive composition 2 further contains the following component (E).
(E) component: silane coupling agent The sealing body according to claim 7, wherein the content of component (E) is 0.01 to 10 parts by mass with respect to 100 parts by mass of component (A). The encapsulant according to any one of claims 1 to 8, wherein said volatile antioxidant is a hindered phenolic antioxidant. The sealing body according to any one of claims 1 to 9, wherein the thickness of the adhesive layer constituting said adhesive sheet 1 is 5 to 25 µm. The sealing body according to any one of claims 1 to 10, wherein the adhesive sheet 1 further has a release film.