TWI758484B - Adhesive composition, adhesive sheet and seal - Google Patents

Abstract

The adhesive composition of the present invention contains: (A) component: modified polyolefin-based resin, (B) component: polyfunctional epoxy compound that is liquid at 25°C, and (C) which may be contained Component: An adhesive composition of a polyfunctional epoxy compound that is solid at 25°C, characterized in that the total amount of (B) component and (C) component exceeds 100 with respect to 100 parts by mass of (A) component parts by mass. The present invention also provides an adhesive sheet having an adhesive layer formed by using the adhesive composition, and a sealing body in which a to-be-sealed object is sealed by the above-mentioned adhesive sheet. According to the present invention, it is possible to provide an adhesive composition that can be easily formed into a sheet, an adhesive sheet having an adhesive layer formed using the adhesive composition and having an excellent unevenness tracking property, and a to-be-sealed object sealed with the above-mentioned adhesive sheet. of the seal.

Description

Adhesive composition, adhesive sheet and seal

The present invention relates to an adhesive composition that can be easily formed into a sheet; an adhesive sheet having an adhesive layer formed using the adhesive composition and having excellent unevenness tracking properties; and a sealed body sealed by the above-mentioned adhesive sheet .

In recent years, an organic EL element has been attracting attention as a light-emitting element capable of emitting light with high brightness by low-voltage direct current driving. However, the organic EL element has a problem that light emission characteristics such as light emission luminance, light emission efficiency, and light emission uniformity are likely to deteriorate over time. The reason for the reduction in light emission characteristics is considered to be due to the penetration of oxygen, moisture, etc. into the organic EL element, resulting in deterioration of electrodes and organic layers. Therefore, the organic EL element is sealed with a sealing material to prevent oxygen and moisture. infiltrate. When sealing an organic EL element with a sealing material, it is necessary to bury minute gaps and unevennesses of the organic EL element, and thus it has been known to develop a sealing material with a low viscosity.

For example, the composition described in Patent Document 1 is a resin composition containing a specific epoxy resin, a specific epoxy resin hardener, a specific microcapsule, and a specific amount of filler, and is measured by an E-type viscometer at 25°C, 2.5 The viscosity at rpm is 0.5~50Pa·s. Patent Document 1 also describes that by using a liquid epoxy resin and a liquid epoxy resin curing agent, and adjusting the filler content, both low viscosity and high moisture resistance of the cured product can be achieved. [Prior Art Documents] [Patent Documents]

[Patent Document 1] WO2012/014499 (US2013128435 A1)

(The problem to be solved by the invention)

The composition described in Patent Document 1 has a low viscosity and is excellent in uneven tracking properties. However, since the composition has fluidity before the hardening reaction, it is necessary to use a special coating device such as a dispenser when sealing the organic EL element. Therefore, an adhesive composition that can be easily formed into a sheet and can form an adhesive layer excellent in uneven tracking properties is expected.

The present invention has been made in view of the above-mentioned facts, and an object of the present invention is to provide an adhesive composition that can be easily formed into a sheet shape, an adhesive sheet having an adhesive layer formed using the adhesive composition and having excellent unevenness tracking properties, and an adhesive sheet that can be sealed It is a sealing body formed by sealing with the above-mentioned adhesive sheet. (means to solve the problem)

The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems, and as a result, they have found that: (i) an adhesive composition containing a modified polyolefin-based resin and one or more types of polyfunctional epoxy compounds has better properties than modified polyolefin resins. An adhesive composition in which 100 parts by mass of polyolefin-based resin, the total amount of polyfunctional epoxy compounds exceeds 100 parts by mass, and at least one of the polyfunctional epoxy compounds is liquid at 25°C, which can be easily formed into sheet-like; (ii) the adhesive layer formed by using the adhesive composition is excellent in tracking properties of concavities and convexities, and the present invention has been completed.

The reason is that according to the present invention, the following adhesive compositions of (1) to (11), the adhesive sheets of (12) to (14), and the sealing bodies of (15) and (16) are provided. (1) An adhesive composition comprising the following (A) components and (B) components, and may also contain (C) components, characterized in that relative to 100 mass of (A) components parts, and the total amount of (B) component and (C) component exceeds 100 parts by mass. (A) Component: Modified polyolefin resin The adhesive composition according to (1), wherein the component (A) is an acid-modified polyolefin-based resin. (3) The adhesive composition according to (1), wherein the total amount of the above-mentioned (B) component and (C) component is more than 100 parts by mass and 200 parts by mass or less with respect to 100 parts by mass of the above-mentioned (A) component . (4) The adhesive composition as described in (1) containing the said (C)component. (5) The adhesive composition according to (4), wherein the content ratio (mass ratio) of the component (B) and the component (C) is [(B) component:(C) component]=100:1 ~1:1. (6) The adhesive composition according to (1), further comprising the following (D) component: (D) component: a tackifier having a softening point of 80° C. or higher (7) as described in (6) The adhesive composition as described in which the content of the said (D) component is 1-200 mass parts with respect to 100 mass parts of said (A) components. (8) The adhesive composition according to (1), further comprising the following (E) component: (E) Component: imidazole-based curing catalyst (9) The adhesive composition according to (8) The content of the component (E) is 1 to 10 parts by mass relative to 100 parts by mass of the total amount of the component (B) and the component (C). (10) The adhesive composition according to (1), further comprising the following (F) component: (F) component: silane coupling agent (11) The adhesive composition according to (10), However, content of the said (F) component is 0.01-10 mass parts with respect to 100 mass parts of said (A) components. (12) An adhesive sheet having an adhesive layer, wherein the adhesive layer is formed using the adhesive composition according to any one of (1) to (11). (13) The adhesive sheet according to (12), wherein the thickness of the adhesive layer is 5 to 25 μm. (14) The adhesive sheet according to (12), further comprising a release film. (15) A sealing body which is sealed by using the adhesive sheet according to any one of (12) to (14) to be sealed. (16) The sealing body according to (15), wherein the material to be sealed is an organic EL element, an organic EL display element, a liquid crystal display element, or a solar cell element. [Inventive effect]

According to the present invention, it is possible to provide an adhesive composition that can be easily formed into a sheet, an adhesive sheet having an adhesive layer formed using the adhesive composition and having an excellent unevenness tracking property, and a to-be-sealed object sealed with the above-mentioned adhesive sheet. of the seal.

Hereinafter, the present invention will be described in detail separately for 1) the adhesive composition, 2) the adhesive sheet, and 3) the sealing body.

1) Adhesive composition The adhesive composition of the present invention contains the following (A) components and (B) components, and may also contain (C) components, wherein, relative to (A) component 100 In parts by mass, the total amount of the (B) component and the (C) component exceeds 100 parts by mass. (A) Component: Modified polyolefin-based resin (B) Component: Polyfunctional epoxy compound that is liquid at 25°C (C) Component: Polyfunctional epoxy compound that is solid at 25°C

(A) Component: Modified polyolefin-based resin The adhesive composition of the present invention is a modified polyolefin-based resin containing the (A) component. The adhesive composition of the present invention is excellent in adhesive strength by containing the modified polyolefin-based resin. Moreover, by using the adhesive composition containing the modified polyolefin resin, a thinner adhesive layer can be efficiently formed.

The modified polyolefin resin is a polyolefin resin into which a functional group is introduced by subjecting a precursor polyolefin resin to a modification treatment using a modifying agent.

The term "polyolefin resin" refers to a polymer containing repeating units derived from olefin-based monomers. Polyolefin resins may be polymers consisting of repeating units derived from olefin-based monomers alone, repeating units derived from olefin-based monomers, and repeating units derived from monomers that can be copolymerized with olefin-based monomers. Units, which make up the aggregates.

The olefin-based monomer is preferably an α-olefin having 2 to 8 carbon atoms, more preferably ethylene, propylene, 1-butene, isobutylene, or 1-hexene, and particularly preferably ethylene or propylene. These olefin-based monomer systems may be used alone or in combination of two or more. As a monomer system which can be copolymerized with an olefin type monomer, vinyl acetate, (meth)acrylate, styrene, etc. are mentioned, for example. These monomer systems which can be copolymerized with the olefin-based monomer can be used alone or in combination of two or more.

Examples of polyolefin resins include: very low density polyethylene (VLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene, polyethylene Propylene (PP), ethylene-propylene copolymer, olefin-based elastomer (TPO), ethylene-vinyl acetate copolymer (EVA), ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate copolymer Wait.

The modifier used when the polyolefin resin is modified is a compound having a functional group in the molecule. Examples of functional groups include carboxyl groups, carboxylic acid anhydride groups, carboxylate ester groups, hydroxyl groups, epoxy groups, amide groups, ammonium groups, nitrile groups, amine groups, amide groups, isocyanate groups, acetyl groups, sulfur groups Alcohol group, ether group, thioether group, sulfo group, phosphine group, nitro group, urethane group, halogen atom, etc. Among them, carboxyl group, carboxylic acid anhydride group, carboxylate ester group, hydroxyl group, ammonium group, amine group, imide group, isocyanate group are preferable, carboxylic acid anhydride group, alkoxysilyl group are more preferable, and alkoxysilyl group is particularly preferable Carboxylic acid anhydride group. The compound which has a functional group may have two or more types of functional groups in a molecule|numerator.

Examples of the modified polyolefin-based resins include acid-modified polyolefin-based resins and silane-modified polyolefin-based resins. From the viewpoint of obtaining more excellent effects of the present invention, acid-modified polyolefin-based resins are preferred.

The term "acid-modified polyolefin-based resin" refers to a polyolefin resin that is graft-modified with an acid. For example, a polyolefin resin is reacted with an unsaturated carboxylic acid or an unsaturated carboxylic acid anhydride (hereinafter collectively referred to as "unsaturated carboxylic acid, etc.") to introduce a carboxyl group or a carboxylic acid anhydride group (graft modification).

Unsaturated carboxylic acids and the like to be reacted with polyolefin resins include, for example, maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaric acid, tetrahydrophthalic acid, and aconitum Unsaturated carboxylic acids such as acid; unsaturated carboxylic anhydrides such as maleic anhydride, itaconic anhydride, glutaric anhydride, citraconic anhydride, aconitic anhydride, norenedicarboxylic anhydride, tetrahydrophthalic anhydride, etc. These systems can be used individually by 1 type or in combination of 2 or more types. Among them, maleic anhydride is preferred from the viewpoint of easily obtaining an adhesive composition having a higher adhesive strength.

The amount of the unsaturated carboxylic acid 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, and particularly preferably 0.2 to 1.0 parts by mass relative to 100 parts by mass of the polyolefin resin . The adhesive composition containing the acid-modified polyolefin-based resin thus obtained has more excellent adhesive strength.

A commercially available thing can also be used for acid-modified polyolefin resin. Examples of commercially available products include ADMER (registered trademark) (manufactured by Mitsui Chemicals Corporation), UNISTOLE (registered trademark) (manufactured by Mitsui Chemicals Corporation), BondyRam (manufactured by Polyram Corporation), orevac (registered trademark) (manufactured by ARKEMA Corporation), MODIC (registered trademark) (manufactured by Mitsubishi Chemical Corporation) and the like.

The so-called "silane-modified polyolefin-based resin" refers to a polyolefin resin that is graft-modified using an unsaturated silane compound. The silane-modified polyolefin resin has a structure in which an unsaturated silane compound belonging to the side chain is graft-copolymerized on the main chain of the polyolefin resin. For example: silane-modified polyethylene resin and silane-modified ethylene-vinyl acetate copolymer. Among them, the preferable ones are silane-modified polyethylene resins such as silane-modified low-density polyethylene, silane-modified ultra-low-density polyethylene, and silane-modified linear low-density polyethylene.

The unsaturated silane compound to be reacted with the polyolefin resin is preferably an ethylene silane compound, such as ethylene trimethoxy silane, ethylene triethoxy silane, ethylene tripropoxy silane, ethylene triisopropoxy silane Silane, Ethylene Tributoxy Silane, Ethylene Tripentoxy Silane, Ethylene Triphenoxy Silane, Ethylene Tribenzyloxy Silane, Ethylene Trimethylene Dioxy Silane, Ethylene Triethylene Dioxy Silane, Vinyl Acrylic Acid Oxysilane, ethylene triacetoxysilane, ethylene tricarboxysilane, etc. These systems can be used individually by 1 type or in combination of 2 or more types. When the unsaturated silane compound is graft-polymerized to the polyolefin resin belonging to the main chain, a conventional method of known graft-polymerization can be adopted for the conditions.

The amount of the unsaturated silane compound to be reacted with the polyolefin resin is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 7 parts by mass, and particularly preferably 0.5 to 5 parts by mass relative to 100 parts by mass of the polyolefin resin. By making the amount of the unsaturated silane compound reacted within the above-mentioned range, the adhesive composition containing the obtained silane-modified polyolefin-based resin becomes more excellent in adhesive strength.

The silane-modified polyolefin-type resin can also use a commercial item. As a commercially available product, for example, LINKLON (registered trademark) (manufactured by Mitsubishi Chemical Corporation) and the like can be used. Especially preferably, LINKLON of low-density polyethylene system, LINKLON of linear low-density polyethylene system, LINKLON of ultra-low-density polyethylene system, and LINKLON of ethylene-vinyl acetate copolymer system can be used.

The modified polyolefin-based resins may be used alone 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)-based solvent of the modified polyolefin-based resin can be determined in terms of standard polystyrene by performing gel permeation chromatography (GPC) using tetrahydrofuran (THF).

(B) Component: a liquid polyfunctional epoxy compound at 25°C The adhesive composition of the present invention contains a 25°C liquid polyfunctional epoxy compound of the (B) component. The "polyfunctional epoxy compound that is liquid at 25°C" refers to a polyfunctional epoxy compound that has a certain volume (excluding volatile components) at 25°C, but has an indeterminate shape. The viscosity at 25°C of the "liquid polyfunctional epoxy compound at 25°C" used in the present invention is usually 0.1-100,000 mPa·s, preferably 0.2-50,000 mPa·s, more preferably 0.3-10,000 mPa·s s. The component (B) has the effect of lowering the storage elastic modulus of the adhesive composition when the adhesive composition is at a high temperature (hereinafter also referred to as "storage elastic modulus lowering effect"). Therefore, by using the adhesive composition of the present invention, it is possible to efficiently form an adhesive layer excellent in uneven tracking properties.

The "polyfunctional epoxy compound" refers to a compound having two or more epoxy groups in the molecule.

(B) Component system, for example: 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, etc. (B) The polyfunctional epoxy compound system of a component can be used individually by 1 type or in combination of 2 or more types. The molecular weight of the polyfunctional epoxy compound of the component (B) is preferably 700 to 5,000, more preferably 1,200 to 4,500. By using the adhesive composition containing the component (B) having a molecular weight of 700 or more, a sealing material with lower outgassing properties can be easily obtained. On the other hand, since the adhesive composition containing the component (B) having a molecular weight of 5,000 or less has better fluidity, the use of such an adhesive composition can easily form an adhesive layer with better uneven tracking properties .

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

(C)component: the polyfunctional epoxy compound which is solid at 25 degreeC The adhesive composition of this invention may contain the polyfunctional epoxy compound which is solid at 25 degreeC of (C)component. The "polyfunctional epoxy compound that is solid at 25°C" refers to a polyfunctional epoxy resin having a softening point in a temperature range of 25°C or higher. The polyfunctional epoxy compound of (C) component is different from the polyfunctional epoxy compound of (B) component, and it is thought that it has almost no storage elastic modulus lowering effect. Therefore, when the adhesive composition containing the (C) component in place of the (B) component is used, the storage elastic modulus hardly decreases even at high temperature. However, when the component (C) is used in combination with the component (B), the effect of reducing the storage elastic modulus of the component (B) can be further enhanced. The reason is considered that the presence of the component (C) increases the sea area ratio of the sea-island structure described later. Moreover, since (C)component also has the effect of improving the film-forming property of an adhesive composition, the adhesive composition containing (C)component can be formed into a sheet shape more easily. Therefore, it is more preferable that the adhesive composition of this invention contains (C)component.

(C) Component system, for example: 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, etc. (C) The polyfunctional epoxy compound system of a component can be used individually by 1 type or in combination of 2 or more types. The molecular weight of the polyfunctional epoxy compound of the component (C) is preferably 500 to 10000, more preferably 1000 to 5000.

In the adhesive composition of the present invention, with respect to 100 parts by mass of (A) component, the total amount of (B) component and (C) component [when the adhesive composition does not contain (C) component, refers to (B) The component content (the same applies hereinafter)] is more than 100 parts by mass, preferably more than 100 parts by mass and not more than 200 parts by mass, and more preferably not less than 120 parts by mass and not more than 200 parts by mass. When the total amount of the component (B) and the component (C) exceeds 100 parts by mass relative to 100 parts by mass of the component (A), it is possible to efficiently form the compound having the modified polyolefin resin (component (A)). "Island" and a sea-island structure adhesive layer consisting of a "sea" of polyfunctional epoxy compounds (component (B) and component (C)). The adhesive layer of such a sea-island structure is excellent in uneven tracking properties because the storage modulus of elasticity during heating is greatly reduced.

When the adhesive composition of the present invention contains (C) component, the content ratio (mass ratio) of (B) component and (C) component is preferably [(B) component:(C) component]=100:1 ~1:1, preferably 10:1~2:1. When the amount of (C)component with respect to (B)component increases, there exists a tendency to maintain a fixed shape easily when shaping|molding an adhesive composition into a sheet shape.

The adhesive composition of this invention may contain components other than the said (A) component, (B) component, and (C) component. Components other than (A) component, (B) component, and (C) component can be, for example, the following (D) component, (E) component, and (F) component. (D) Component: Tackifier with a softening point of 80°C or higher (E) Component: Imidazole-based hardening catalyst (F) Component: Silane coupling agent

(D) Component: Tackifier having a softening point of 80°C or higher The adhesive composition containing the (B) component has a low storage elastic modulus before curing and is excellent in uneven tracking properties. However, such an adhesive composition may be difficult to maintain a certain shape, and it may be difficult to shape into a sheet. In particular, when the component (C) is not contained, or when the content of the component (C) is small, it is likely to be difficult to form into a sheet. In this case, by containing the component (D), the formability can be improved.

The tackifier of the component (D) is a tackifier having a softening point of 80°C or higher, and the rest are not particularly limited. Examples include: rosin-based resins such as polymerized rosin, polymerized rosin esters, and rosin derivatives; terpene-based resins such as polyterpene resins, aromatic modified terpene resins and their hydrogenated products, and terpene phenol resins; coumarone-indene Resins; aliphatic petroleum resins, aromatic petroleum resins and their hydrides, petroleum resins such as aliphatic/aromatic copolymer petroleum resins; low molecular weight polymers of styrene or substituted styrene; α-methylstyrene monomer Polymer resin, α-methylstyrene/styrene copolymer resin, styrene monomer/aliphatic monomer copolymer resin, styrene monomer/α-methylstyrene/aliphatic Styrene resins such as monomer copolymerization resins, styrene monomer monomer resins, styrene monomer/aromatic monomer copolymerization resins, and the like. Among them, a styrene-based resin is preferable, and a styrene-based monomer/aliphatic monomer copolymerized resin is more preferable. These tackifiers may be used alone or in combination of two or more.

By using a tackifier having a softening point of 80°C or higher, an adhesive composition having excellent tackiness at high temperature can be obtained. Moreover, the workability|operativity at the time of shaping|molding the adhesive composition into a sheet shape is also improved.

When the adhesive composition of this invention contains (D) component, the content is preferably 1-200 mass parts, more preferably 10-150 mass parts with respect to 100 mass parts of said (A) components. When the content of the component (D) is too small, the adhesive composition may be difficult to form into a sheet. On the other hand, when the content of the component (D) is too large, the adhesive layer may become brittle.

(E) Component: imidazole-based curing catalyst imidazole-based curing catalysts include, for example: 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2- Ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dimethylol Imidazole etc. Among these, 2-ethyl-4-methylimidazole is preferable. These imidazole-based hardening catalysts may be used alone or in combination of two or more.

By using an adhesive composition containing an imidazole-based hardening catalyst, a cured product having excellent adhesiveness even at high temperature can be easily obtained.

When the adhesive composition of the present invention contains (E) component, the content is preferably 1 to 10 parts by mass, more preferably 100 parts by mass of the total amount of the above-mentioned (B) component and (C) component. 2 to 5 parts by mass. The hardened product of the adhesive composition having the imidazole-based hardening catalyst content in this range has excellent adhesiveness even at high temperature.

(F) Component: Silane Coupling Agent As the silane coupling agent, a known silane coupling agent can be used. Among them, an organosilicon compound having at least one alkoxysilyl group in the molecule is preferable. Examples of silane coupling agents include polymerizable unsaturated group-containing silicon compounds such as ethylene trimethoxy silane, ethylene triethoxy silane, methacryloyloxypropyl trimethoxy silane; 3-glycidoxy silane Silicon compounds with epoxy structures such as propyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane;3 -aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-8-aminooctyltrimethoxysilane, N -(2-Aminoethyl)-3-aminopropylmethyldimethoxysilane and other amine-containing silicon compounds; 3-chloropropyltrimethoxysilane; 3-isocyanatopropyltriethoxysilane , 3-mercaptopropyl trimethoxysilane, 3-trimethoxysilyl propyl succinic anhydride, etc. These silane coupling agents may be used alone or in combination of two or more.

By using an adhesive composition containing a silane coupling agent, a cured product with better adhesive strength in normal temperature and high temperature environments can be easily obtained.

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

The adhesive composition of the present invention may also contain a solvent. Examples of the solvent system include aromatic hydrocarbon-based solvents such as benzene and toluene; ester-based solvents such as ethyl acetate and butyl acetate; ketone-based solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; Alicyclic hydrocarbon-based solvents such as heptane; alicyclic hydrocarbon-based solvents such as cyclopentane, cyclohexane, and methylcyclohexane; and the like. These solvent systems can be used individually by 1 type or in combination of 2 or more types. The solvent content can be appropriately determined in consideration of coatability and the like.

The adhesive composition of this invention may contain other components in the range which does not inhibit the effect of this invention. Examples of the other components include additives such as ultraviolet absorbers, antistatic agents, light stabilizers, antioxidants, resin stabilizers, fillers, pigments, extenders, and softeners. These systems 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 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 storage elastic modulus of the adhesive composition of the present invention is measured for its solid content, the storage elastic modulus at 23°C is preferably 0.1-600 MPa, more preferably 0.2-500 MPa. By storing the elastic modulus at 23°C above 0.1 MPa, it can be easily formed into a thin sheet. On the other hand, when the storage elastic modulus at 23° C. is 600 MPa or less, a relatively soft adhesive layer with excellent sealing properties can be formed. In this specification, the "solid content" refers to the solid content excluding volatile substances such as solvents.

When the storage elastic modulus of the adhesive composition of the present invention is measured for its solid content, the upper limit of the storage elastic modulus at 80° C. is preferably 0.1 MPa. Adhesive compositions with a storage elastic modulus of 0.1 MPa or less at 80°C tend to have good uneven tracking properties. Furthermore, the lower limit of the storage elastic modulus at 80°C is preferably 1 kPa. The adhesive composition having a storage elastic modulus of 1 kPa or more at 80°C is more excellent in handling properties.

The storage elastic modulus of the solid content of the adhesive composition of the present invention, for example, the sheet-like adhesive obtained by coating the adhesive composition of the present invention and drying it is used as a test piece, and then according to the method described in the examples. Determination.

The adhesive composition having the above-mentioned properties can be efficiently obtained by optimizing the amount of the (B) component and the amount of the (C) component to be used if necessary. Specifically, by adding the (B) component, the storage elastic modulus at 23°C and 80°C tends to be lowered. On the other hand, when the (B) component is excessively added, it may be difficult to form into a sheet. In this case, by adding an appropriate amount of the (C) component, the formability can be improved, and the 80° C. storage elastic modulus can be lowered.

The adhesive composition of the present invention is easy to form into a sheet, and is excellent in uneven tracking properties. Therefore, the adhesive composition of the present invention is quite suitable for forming a sealing material.

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

The thickness of the adhesive layer of the adhesive sheet is not particularly limited, but is preferably 5 to 25 μm, more preferably 10 to 20 μm. An adhesive layer having a thickness within the above range is quite suitable as a sealing material.

The adhesive sheet of the present invention may also be provided with a release film. The release film functions as a support in the production process of the adhesive sheet, and functions as a protective sheet for the adhesive layer until the adhesive sheet is used. When the adhesive sheet of the present invention is used, the release film is usually peeled and removed.

For the release film, a known one can be used. For example, a release layer subjected to release treatment with a release agent is provided on the base material for release films. Examples of the base material for the release film include paper base materials such as cellophane, coated paper, and fine paper; laminated paper in which thermoplastic resins such as polyethylene are laminated on these paper base materials; and polyethylene terephthalate Diester resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polypropylene resin, polyethylene resin and other plastic films, etc. Examples of release agents include rubber-based elastomers such as polysiloxane-based resins, olefin-based resins, isoprene-based resins, and butadiene-based resins; long-chain alkyl-based resins, alkyd-based resins, and fluorine-based resins Wait.

When the adhesive sheet of the invention has a release film, the number of release films may be one or two, and usually one (two in total) release films are provided on both sides of the adhesive layer. In this case, the two peeling films may be the same or different, but preferably the two peeling films have different peeling forces. Because the peeling force of the two peeling films is different, the adhesive sheet is less prone to problems when used. That is, by setting the peeling force of the two peeling films to be different, the step of tearing the peeling film first can be performed efficiently.

The manufacturing method of an adhesive sheet is not specifically limited. Adhesive sheets can be produced, for example, using a casting method. When an adhesive sheet is produced by a casting method, by using a known method, the adhesive composition of the present invention is applied to the release-treated surface of the release film, and the obtained coating film is dried to produce an adhesive with a release film layer, and then an adhesive sheet can be obtained by overlapping 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, and gravure coating. The drying conditions when the coating film is dried can be, for example, a drying temperature of 80 to 150° C. and a drying time of 30 seconds to 5 minutes.

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

The 23°C tear-off adhesive strength of the hardened adhesive layer is usually 1~100N/25mm, preferably 10~50N/25mm. In addition, the tear-off adhesion strength at 85°C is usually 1 to 100N/25mm, preferably 5 to 50N/25mm. 23°C tear-off adhesion strength is based on JIS Z0237:2009, under the conditions of temperature 23°C, relative humidity 50%, and temperature 85°C (uncontrolled humidity), respectively, according to the peeling angle of 180°. measurable. The water vapor transmission rate of the adhesive layer after hardening treatment is usually 0.1~200g‧m ^-2 ‧day ^-1 , preferably 1~150g‧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 excellent in uneven tracking properties. Therefore, by using the adhesive sheet of this invention, an organic electroluminescent element etc. can be sealed without a gap.

3) Sealing body The sealing system of the present invention is sealed using the adhesive sheet of the present invention. The sealing system 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, and the sealing material may be, for example, an adhesive layer derived from the adhesive sheet of the present invention (hardened product of the adhesive layer).

The substrate is not particularly limited, and various substrate materials can be used. It is particularly preferable to use a substrate material with high visible light transmittance. In addition, it is preferable to use a material that has high blocking performance against moisture and gas to penetrate from the outside of the element, and is excellent in solvent resistance and weather resistance. Specific examples include transparent inorganic materials such as quartz and glass; polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polystyrene, polyethylene, polypropylene, polyphenylene sulfide, Transparent plastics such as polyvinylidene fluoride, cellulose acetate, brominated phenoxy, aramides, polyimides, polystyrenes, polyarylates, polysaccharides, and polyolefins; the aforementioned gas barrier Sex films, etc. The thickness of the substrate is not particularly limited, and can be appropriately selected after considering the light transmittance and the performance inside and outside the blocking element.

As a to-be-sealed object system, an organic EL element, an organic EL display element, a liquid crystal display element, a solar cell element, etc. are mentioned, for example.

The manufacturing method of the sealing body of this invention is not specifically limited. For example, after overlapping the adhesive layer of the adhesive sheet of the present invention on the object to be sealed, heating is applied to make the adhesive layer of the adhesive sheet and the object to be sealed adhere. Next, the sealing body of this invention can be manufactured by hardening this adhesive bond layer.

Adhesion conditions for adhering the adhesive layer of the adhesive sheet to the object to be sealed are not particularly limited. The adhesion temperature is, for example, 23 to 100°C, preferably 40 to 80°C. The adhesion treatment may be performed while applying pressure. The hardening conditions at the time of hardening the adhesive layer can be those described above.

The sealing system of the present invention is sealed by means of the adhesive sheet of the present invention. Therefore, the sealing system of the present invention can maintain the performance of the sealed object for a long time. [Example]

Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited in any way by the following examples. "Part" and "%" in each example are the quality standards unless otherwise stated.

[Example 1] 100 parts of an acid-modified polyolefin-based resin (acid-modified α-olefin polymer, manufactured by Mitsui Chemicals Co., Ltd., trade name: UNISTOLEH-200, number average molecular weight: 47,000), a polyfunctional epoxy compound (1) (Hydrogenated bisphenol A epoxy resin, manufactured by Mitsubishi Chemical Corporation, trade name: YX8034, liquid at 25°C, epoxy equivalent 270 g/eq) 125 parts, tackifier (styrene-based monomer aliphatic Monomer copolymer, softening point 95°C, manufactured by Mitsui Chemicals Co., Ltd., trade name: FTR6100) 50 parts, and imidazole-based hardening catalyst (manufactured by Shikoku Chemical Co., Ltd., trade name: Curezol 2E4MZ, 2-ethyl-4- Methylimidazole) 1.25 parts, was dissolved in methyl ethyl ketone, and prepared the adhesive composition 1 with a solid content concentration of 32%. The adhesive composition 1 was applied to the peeling-treated surface of a release film (manufactured by Lintec, trade name: SP-PET382150), and the obtained coating film was dried at 100° C. for 2 minutes to form an adhesive with a thickness of 12 μm. The adhesive sheet 1 was obtained by bonding the peeling-treated surface of another release film (manufactured by Lintec, trade name: SP-PET381031) to the agent layer.

[Example 2] Except that in Example 1, the amount of the polyfunctional epoxy compound (1) was changed to 150 parts, and the amount of the imidazole-based hardening catalyst was changed to 1.5 parts, the rest were carried out in the same manner as Example 1 The adhesive sheet 2 was obtained in the same manner.

[Example 3] 100 parts of an acid-modified polyolefin-based resin (acid-modified α-olefin polymer, manufactured by Mitsui Chemicals, trade name: UNISTOLEH-200, number average molecular weight: 47,000), a polyfunctional epoxy compound (2) (Hydrogenated bisphenol A epoxy resin, manufactured by Mitsubishi Chemical Corporation, trade name: YX8000, liquid at 25°C, epoxy equivalent: 205 g/eq) 100 parts, polyfunctional epoxy compound (3) ( Hydrogenated bisphenol A epoxy resin, manufactured by Mitsubishi Chemical Corporation, trade name: YX8040, solid at 25°C, epoxy equivalent: 1100 g/eq) 25 parts, imidazole-based hardening catalyst (manufactured by Shikoku Chemical Co., Ltd., trade name : Curezol 2E4MZ, 1 part of 2-ethyl-4-methylimidazole), and 0.1 part of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM4803) were dissolved in methyl ethyl ketone to prepare 25% solid content Adhesive Composition 2. The adhesive composition 2 was applied to the peeling-treated surface of a release film (manufactured by Lintec, trade name: SP-PET382150), and the obtained coating film was dried at 100° C. for 2 minutes to form an adhesive with a thickness of 12 μm. The adhesive sheet 3 was obtained by bonding the peeling-treated surface of another release film (manufactured by Lintec, trade name: SP-PET381031) to the agent layer.

[Example 4] Adhesive composition 3 was prepared in the same manner as in Example 3 except that the amount of the polyfunctional epoxy compound (3) was changed to 50 parts, and the adhesive composition 3 was used. Adhesive sheet 4 is obtained.

[Comparative Example 1] In Example 1, except that the amount of the polyfunctional epoxy compound (1) was changed to 100 parts, and the amount of the imidazole-based hardening catalyst was changed to 1.0 parts, the rest were carried out in the same manner as Example 1 The adhesive sheet 5 was obtained in the same manner.

The following tests were performed on the adhesive sheets 1 to 5 obtained in Examples 1, 2 and Comparative Example 1. [Measurement of Storage Elasticity Modulus] The adhesive layers of the adhesive sheets obtained in Examples or Comparative Examples were stacked, and laminated at 23° C. using a thermocompressor to obtain a laminated body having a thickness of 1 mm. This laminate was used as a sample, and the storage elastic modulus of the adhesive layer before curing was measured using a storage elastic modulus measuring device (Physica MCR301, manufactured by Anton Paar) at a frequency of 1 Hz and a temperature range of 23 to 150°C. The storage elastic modulus coefficients at 23°C and 80°C are shown in Table 1.

[Evaluation of Embeddability of Concavities and Concavities] The adhesive layer of the adhesive sheet obtained in Examples or Comparative Examples was overlapped with a polyethylene terephthalate film (PET) having a thickness of 25 μm to obtain an adhesive layer with PET. On the other hand, a small piece of polyethylene terephthalate with a thickness of 10 μm was left standing on a glass substrate (simulation device). The above-mentioned adhesive layer with PET was superimposed on the glass substrate in such a manner that the adhesive layer was opposite to the glass substrate and completely covered the simulation device on the glass substrate. Next, after heating these to 60 degreeC using a thermocompression bonding machine, the adhesive bond layer was hardened under the conditions of 100 degreeC and 2 hours. Observation was carried out with an optical microscope to investigate whether or not the unevenness was lifted, and the unevenness burying property was evaluated according to the following criteria. ○: No floating. ×: There is floating. The evaluation results are shown in Table 1.

[Table 1]

The following items are known from Table 1. The adhesive sheet-based polyfunctional epoxy compound content of Examples 1 to 4 is higher than that of the modified polyolefin-based resin. In addition, the adhesive sheets of Examples 3 and 4 contained both the polyfunctional epoxy compound in a liquid state at 25°C and the polyfunctional epoxy compound in a solid state at 25°C. Compared with the adhesive sheet of Comparative Example 1, these adhesive sheets had lower elastic modulus in storage at 80°C, and were excellent in burial properties of concavities and convexities.

without

without.

Claims (16)

An adhesive composition containing the following (A) components and (B) components, and also containing (C) components, is characterized in that: with respect to 100 parts by mass of (A) components, ( The total amount of B) component and (C) component exceeds 100 parts by mass; (A) component: modified polyolefin-based resin (B) component: a polyfunctional group having a molecular weight of 700 to 5,000 and being liquid at 25°C Epoxy compound (C) component: a polyfunctional epoxy compound having a molecular weight of 1,000 to 5,000 and being solid at 25°C. The adhesive composition according to claim 1, wherein the component (A) is an acid-modified polyolefin-based resin. The adhesive composition of claim 1, wherein the total amount of the above-mentioned (B) component and (C) component is more than 100 parts by mass and 200 parts by mass or less with respect to 100 parts by mass of the above-mentioned (A) component. The adhesive composition according to any one of claims 1 to 3 of the scope of application, which contains the above-mentioned (C) component. The adhesive composition according to claim 4, wherein the content ratio (mass ratio) of the above-mentioned (B) component and (C) component is [(B) component:(C) component]=100:1~1 :1. The adhesive composition according to claim 1, further comprising the following (D) component: (D) component: an adhesive with a softening point of 80°C or higher. The adhesive composition according to claim 6, wherein the content of the component (D) is 1 to 200 parts by mass relative to 100 parts by mass of the component (A). The adhesive composition of claim 1 of the scope of the application further comprises the following (E) component: (E) component: imidazole-based hardening catalyst. The adhesive composition of claim 8, wherein the content of the component (E) is 1 to 10 parts by mass relative to 100 parts by mass of the total amount of the component (B) and the component (C). The adhesive composition according to claim 1, further comprising the following (F) component: (F) component: a silane coupling agent. The adhesive composition according to claim 10, wherein the content of the component (F) is 0.01 to 10 parts by mass relative to 100 parts by mass of the component (A). An adhesive sheet is an adhesive sheet with an adhesive layer, wherein the above-mentioned adhesive layer is formed by using the adhesive composition of any one of items 1 to 11 of the patent application scope. As for the adhesive sheet of claim 12, the thickness of the adhesive layer is 5-25 μm. The adhesive sheet of claim 12 of the scope of the application is further provided with a release film. A sealing body is sealed by using the adhesive sheet according to any one of items 12 to 14 of the patent application scope. The sealing body of Claim 15 whose said to-be-sealed material is an organic EL element, an organic EL display element, a liquid crystal display element, or a solar cell element.