TW202239928A - Acrylic pressure-sensitive adhesive sheet, acrylic pressure-sensitive adhesive composition, pressure-sensitive adhesive film, and flexible device - Google Patents

Abstract

Provided are: an acrylic pressure-sensitive adhesive sheet which, even when the pressure-sensitive adhesive layer has a reduced thickness, can have both excellent tackiness and excellent elasticity; an acrylic pressure-sensitive adhesive composition which forms the acrylic pressure-sensitive adhesive sheet; a pressure-sensitive adhesive film including a pressure-sensitive adhesive layer constituted from the acrylic pressure-sensitive adhesive sheet; and a flexible device including the pressure-sensitive adhesive film. The acrylic pressure-sensitive adhesive sheet according to an embodiment of the present invention has an adhesive force in application to a polyimide film of 5.5 N/25 mm or greater and an adhesive force in application to a glass of 5.5 N/25 mm or greater, both as measured at 23 DEG C, a peeling rate of 300 mm/min, and a peeling angle of 180 DEG, and has a storage modulus G' at -20 DEG C of 200 kPa or less and a thickness of 25 [mu]m or less.

Description

Acrylic adhesive sheet, acrylic adhesive composition, adhesive film, and flexible device

The invention relates to an acrylic adhesive sheet, an acrylic adhesive composition, an adhesive film, and a flexible device.

Adhesive film is used for reinforcement or surface protection of components of various shapes.

For example, in the case of bonding an integrated circuit (IC) or a flexible printed circuit board (FPC) to a substrate of a semiconductor element (such as a TFT (thin-film transistor, thin-film transistor) substrate, etc.), usually by anisotropic The conductive film (ACF) is bonded by thermocompression. When such thermocompression bonding is performed, an adhesive film may be pasted on the back side of the substrate of the semiconductor element in advance for reinforcement (for example, Patent Document 1).

Also, with regard to the manufacturing method of so-called flexible devices such as foldable devices and rollable devices that are being developed in recent years, in general, a peeling layer and a flexible film substrate are formed on a support substrate such as glass, and a film substrate is formed on the film substrate. A TFT substrate is formed on it, and an organic EL (Electroluminescence, electroluminescence) layer is formed thereon. Then, the support substrate is peeled off to manufacture a flexible device. However, the flexible display layer is very thin, so defects in the device may occur due to handling or the like. Therefore, an adhesive film may be bonded to the back side for reinforcement (for example, Patent Document 2).

The substrate of the semiconductor element or the flexible device is sometimes bent repeatedly. If the bending characteristics of the adhesive film attached to the substrate etc. bending to cause breakage. Specifically, when an adhesive film is attached to a curved portion (for example, a movable curved portion of a folder, etc.), for example, the following problems arise.

When the adhesive film is bent to have an angle, a compressive force acts on the inner diameter side of the bend, and therefore, the adhesive film itself deforms in an attempt to alleviate the force. Specifically, for example, wrinkles tend to occur.

When the adhesive film is bent to have an angle, tensile stress acts on the outer diameter side of the bend. Therefore, when the stress is relaxed, swelling from the adherend occurs.

When the adhesive film is bent and has an angle, the thickness of the adhesive film at the bent position or the stretched position changes greatly, and in this state, wrinkles or bulges are likely to occur. For example, when the adhesive film is stretched, the thickness of the adhesive film becomes significantly thinner, and swelling from the adherend tends to occur.

In this way, in the conventional adhesive film, it was not possible to sufficiently follow the irregularities at the corners or bends.

As one method for solving the above-mentioned problems, for example, the thickness of the adhesive layer is reduced to increase the elasticity. However, when the thickness of the adhesive layer is made thin, there is a problem that it is difficult to maintain the adhesive force. prior art literature patent documents

Patent Document 1: Japanese Patent No. 5600039 Patent Document 2: Japanese Patent No. 6376271

[Problem to be solved by the invention]

The object of the present invention is to provide an acrylic adhesive sheet having both excellent adhesiveness and excellent elasticity even when the thickness of the adhesive layer is thinned, and an acrylic adhesive forming the acrylic adhesive sheet A composition, an adhesive film having an adhesive layer comprising the acrylic adhesive sheet, and a flexible device provided with the adhesive film. [Technical means to solve the problem]

In the acrylic adhesive sheet according to the embodiment of the present invention, At 23°C, at a peeling speed of 300 mm/min and at a peeling angle of 180 degrees, the adhesion to polyimide film is above 5.5 N/25 mm, and the adhesion to glass is above 5.5 N/25 mm, and The storage modulus G' at -20°C is below 200 kPa, The thickness is 25 μm or less.

The acrylic adhesive composition of the embodiment of the present invention is Forming the acrylic adhesive sheet according to the embodiment of the present invention, It contains an acrylic polymer (P) and an oligomer.

In one embodiment, the acrylic polymer (P) is obtained by polymerizing a monomer component (M) containing a monomer (m5) having a polar group other than a hydroxyl group.

In one embodiment, the content rate of the above-mentioned monomer (m5) having a polar group other than a hydroxyl group in the above-mentioned monomer component (M) is 0.1% by weight to 5.0% by weight.

(通式(1)中，R ¹為碳數1～10之烷基，R ²為氫原子、碳數1～10之烷基或-COOR基，R為碳數1～10之烷基) [化2]

(通式(2)中，R ³為碳數1～10之伸烷基，R ⁴為碳數1～10之烷基，R ⁵為氫原子或甲基) In one embodiment, the above-mentioned monomers (m5) having polar groups other than hydroxyl groups include monomers (1) represented by general formula (1), monomers (2) represented by general formula (2) and at least one of the group consisting of N-vinyl-2-pyrrolidone. [chemical 1]

(In general formula (1), R ¹ is an alkyl group with 1 to 10 carbons, R ² is a hydrogen atom, an alkyl group with 1 to 10 carbons or -COOR group, R is an alkyl group with 1 to 10 carbons) [Chem 2]

(In general formula (2), ^R3 is an alkylene group with ¹ to 10 carbons, R4 is an alkyl group with ¹ to 10 carbons, and R5 is a hydrogen atom or a methyl group)

In one embodiment, the content ratio of the oligomer in the acrylic adhesive composition is 0.1 to 6.5 parts by weight with respect to 100 parts by weight of the acrylic polymer (P).

In one embodiment, the weight average molecular weight Mw of the said oligomer is 1000-30000.

In one embodiment, the monomer component (M) includes an alkyl (meth)acrylate.

In one embodiment, the glass transition temperature Tg of the homopolymer of the said alkyl (meth)acrylate is -10 degreeC or less.

In one Embodiment, the content rate of the said alkyl (meth)acrylate in the said monomer component (M) is 50 weight% - 99 weight%.

In one embodiment, the monomer component (M) includes a hydroxyl group-containing monomer (m4).

In one Embodiment, the content rate of the said hydroxyl group containing monomer (m4) in the said monomer component (M) is 0.01 weight% - 30 weight%.

The adhesive film which concerns on embodiment of this invention has the adhesive agent layer containing the acrylic adhesive agent sheet which concerns on embodiment of this invention.

The flexible device according to the embodiment of the present invention includes the adhesive film according to the embodiment of the present invention. [Effect of Invention]

According to the present invention, it is possible to provide an acrylic adhesive sheet having both excellent adhesiveness and excellent elasticity even when the thickness of the adhesive layer is thinned, and an acrylic adhesive forming the acrylic adhesive sheet A composition, an adhesive film having an adhesive layer comprising the acrylic adhesive sheet, and a flexible device provided with the adhesive film.

In this specification, when it is expressed as "(meth)acrylic acid", it means "acrylic acid and/or methacrylic acid", when it is expressed as "(meth)acrylate", it means "acrylate and/or Methacrylate", when expressed as "(meth)allyl", means "allyl and/or methallyl", when expressed as "(meth)acrolein", means Refers to "acrolein and/or methacrolein". Moreover, in this specification, when expressed as "acid (salt)", it means "acid and/or its salt". Examples of salts include alkali metal salts and alkaline earth metal salts, and specifically, sodium salts, potassium salts, and the like.

"Acrylic Adhesive Sheet" The acrylic adhesive sheet according to the embodiment of the present invention is a sheet-shaped acrylic adhesive. Therefore, what can be handled as an acrylic-type adhesive agent sheet independently may be sufficient, and what is considered as one of constituent members such as an acrylic-type adhesive agent layer may be sufficient.

The adhesive force of the acrylic adhesive sheet according to the embodiment of the present invention to the polyimide film is preferably 5.5 N/25 mm or more, more preferably 6.0 N/25 mm or more, more preferably 6.5 N/25 mm or more, still more preferably 7.0 N/25 mm or more, particularly preferably 7.5 N/25 mm or more, most preferably 8.0 N/25 mm or more. The upper limit of the above-mentioned adhesive force is usually the greater the better, but considering the balance with other adhesive properties, etc., it is preferably below 30 N/25 mm. When the above-mentioned adhesive force is adjusted within the above-mentioned range, sufficient adhesiveness can be exhibited to various adherends such as foldable devices and flexible devices such as rollable devices. The measurement of the above-mentioned adhesive force will be described below.

The adhesive force of the acrylic adhesive sheet according to the embodiment of the present invention to a glass plate is preferably 5.5 N/25 mm or more, more preferably 6.0 N/min at 23° C., a peeling speed of 300 mm/min, and a peeling angle of 180 degrees. 25 mm or more, more preferably 6.5 N/25 mm or more, still more preferably 7.0 N/25 mm or more, particularly preferably 7.5 N/25 mm or more, most preferably 8.0 N/25 mm or more. The upper limit of the above-mentioned adhesive force is usually the greater the better, but considering the balance with other adhesive properties, etc., it is preferably below 30 N/25 mm. When the above-mentioned adhesive force is adjusted within the above-mentioned range, sufficient adhesiveness can be exhibited to various adherends such as foldable devices and flexible devices such as rollable devices. The measurement of the above-mentioned adhesive force will be described below.

Typically, the acrylic adhesive sheet according to the embodiment of the present invention has an adhesive force to the polyimide film at 23° C., a peeling speed of 300 mm/min, and a peeling angle of 180 degrees within the above-mentioned range, and has an adhesive force to glass. The adhesive force is within the above-mentioned range. That the acrylic adhesive sheet according to the embodiment of the present invention has such adhesive properties means that the adherend dependence is lower than the adhesive properties of the acrylic adhesive sheet according to the embodiment of the present invention.

The storage modulus G' at -20°C of the acrylic adhesive sheet according to the embodiment of the present invention is preferably 200 kPa or less, more preferably 180 kPa or less, further preferably 160 kPa or less, still more preferably 150 kPa or less, more preferably less than 140 kPa, particularly preferably less than 130 kPa, most preferably less than 120 kPa. Considering the balance with other adhesive properties, etc., the lower limit of the storage modulus G' is preferably 70 kPa or more. If the said storage modulus G' is adjusted in the said range, the acrylic adhesive sheet which concerns on embodiment of this invention can exhibit the outstanding elasticity. When the said storage modulus G' deviates from the said range and is too large, there exists a possibility that elasticity may fall. The determination of the above-mentioned storage modulus G' will be described below.

The thickness of the acrylic adhesive sheet according to the embodiment of the present invention is preferably 25 μm or less, more preferably 23 μm or less, further preferably 20 μm or less, still more preferably 18 μm or less, especially preferably 15 μm or less , the best is below 13 μm. The thinner the above-mentioned thickness, the better, but in consideration of the balance with other adhesive properties, etc., the lower limit of the above-mentioned thickness is preferably 1 μm or more, more preferably 3 μm or more, and more preferably 5 μm or more, especially preferably 5 μm or more. More than 7 μm, preferably more than 9 μm. When the thickness of the acrylic pressure-sensitive adhesive sheet is within the above-mentioned range, a thinner thickness of the acrylic pressure-sensitive adhesive sheet can be realized.

In the acrylic adhesive sheet according to the embodiment of the present invention, it is more preferable to adjust the above-mentioned adhesive force to the polyimide film, the storage modulus G' at -20°C, and the thickness to be within the above-mentioned range. By adjusting in this way, the acrylic adhesive sheet according to the embodiment of the present invention can have both excellent adhesiveness and excellent elasticity even if the thickness of the adhesive layer is thinned.

The acrylic adhesive sheet according to the embodiment of the present invention is preferably formed from an acrylic adhesive composition.

In this way, the acrylic adhesive sheet can be defined as being formed from the acrylic adhesive composition. This is because the acrylic adhesive sheet becomes an acrylic adhesive sheet due to the crosslinking reaction of the acrylic adhesive composition by heating or ultraviolet radiation, etc. sheet is impossible and almost impractical (“impossible, impractical situation”), therefore, by specifying “formed from an acrylic adhesive composition”, the acrylic adhesive Sheets are properly identified as "things".

When forming the acrylic adhesive sheet according to the embodiment of the present invention from an acrylic adhesive composition, the method for forming such an acrylic adhesive sheet can be adopted within the range that does not impair the effects of the present invention. any suitable method. As a method for forming such an acrylic adhesive sheet, for example, a method of coating an acrylic adhesive composition on any suitable substrate, heating, drying, and curing as necessary , thereby forming an acrylic adhesive sheet on the substrate. Regarding the mechanism of such coating, any appropriate mechanism can be adopted within the range not impairing the effect of the present invention. As such a coating mechanism, for example, a gravure roll coater, a reverse roll coater, a touch roll coater, a dip roll coater, a rod coater, a knife coater, an air knife Coater, Spray Coater, Notch Wheel Coater, Direct Coater, Roller Brush Coater. Heating and drying of the acrylic adhesive composition can employ any appropriate method within the range not impairing the effects of the present invention. As such a method of heating and drying, heating to about 60°C to 180°C may, for example, be mentioned. Curing of the acrylic adhesive composition can employ any appropriate method within the range not impairing the effects of the present invention. As such a curing method, for example, ultraviolet irradiation, laser irradiation, alpha-ray irradiation, beta-ray irradiation, gamma-ray irradiation, X-ray irradiation, and electron beam irradiation may be mentioned.

"Acrylic Adhesive Composition" The acrylic adhesive composition which concerns on embodiment of this invention is an acrylic adhesive composition which forms the acrylic adhesive sheet which concerns on embodiment of this invention.

"Acrylic Polymer (P)" The acrylic adhesive composition according to the embodiment of the present invention preferably contains an acrylic polymer (P). The acrylic polymer (P) may be only 1 type, or may be 2 or more types. When the acrylic adhesive composition of embodiment of this invention contains an acrylic polymer (P), the effect of this invention can be exhibited further.

As the weight average molecular weight Mw of the acrylic polymer (P), any appropriate weight average molecular weight Mw can be adopted within the range that does not impair the effect of the present invention. The weight average molecular weight Mw is preferably 500,000 to 2.5 million, more preferably 800,000 to 2.3 million, further preferably 1 million to 2.2 million, particularly preferably 1.1 million to 2.1 million, most preferably 1.3 million ~1.6 million.

The content ratio of the acrylic polymer (P) in the acrylic adhesive composition according to the embodiment of the present invention is preferably at least 50% by weight, more preferably at least 70% by weight, still more preferably at least 90% by weight, especially It is preferably at least 95% by weight, most preferably at least 97% by weight. The upper limit of the above content ratio is preferably 99.9% by weight or less. If the said content ratio is adjusted in the said range, even if the thickness of an adhesive layer becomes thin, the acrylic adhesive agent sheet which has both excellent adhesiveness and excellent elasticity can be provided.

The acrylic polymer (P) is preferably obtained by polymerizing the monomer component (M).

In this way, the acrylic polymer (P) can be defined as one obtained by polymerizing the monomer component (M). This is because the acrylic polymer (P) becomes the acrylic polymer (P) through the polymerization reaction of the monomer component (M), and it is impossible to directly specify the acrylic polymer (P) from its structure and This situation is almost impractical ("impossible, impractical situation"), therefore, by specifying "obtained by polymerizing the monomer component (M)", the acrylic polymer (P) is properly The land is designated as "things".

The monomer component (M) preferably contains a monomer (m5) having a polar group other than a hydroxyl group. The monomer (m5) which has a polar group other than a hydroxyl group may be only 1 type, and may be 2 or more types.

In terms of further exhibiting the effect of the present invention, the content ratio of the monomer (m5) having a polar group other than the hydroxyl group in the monomer component (M) is preferably 0.01% by weight to 40% by weight, more preferably 0.05% by weight % by weight to 20% by weight, more preferably 0.1% by weight to 10% by weight, more preferably 0.3% by weight to 5.0% by weight, most preferably 0.4% by weight to 4.0% by weight, most preferably 0.5% by weight to 3.5% by weight weight%.

Regarding the monomer (m5) having a polar group other than a hydroxyl group, any suitable monomer having a polar group other than a hydroxyl group can be employed within a range not impairing the effects of the present invention. As such a monomer (m5) having a polar group other than a hydroxyl group, a homopolymer having a glass transition temperature Tg of 100° C. or lower is preferable. The above-mentioned Tg is preferably at most 95°C, more preferably at most 90°C. The lower limit of the above Tg is preferably -30°C or higher, more preferably -10°C or higher. The glass transition temperature Tg of a homopolymer (homopolymer) of a monomer (m5) having a polar group other than a hydroxyl group may affect the adhesive property and bending property of the acrylic polymer (P). By using a monomer having a polar group other than a hydroxyl group whose glass transition temperature Tg of a homopolymer (homopolymer) is within the above-mentioned range as a monomer having a polar group other than a hydroxyl group (m5), the acrylic polymerization can be properly adjusted. The adhesiveness and elasticity of the object (P) can further demonstrate the effect of the present invention.

As a monomer (m5) having a polar group other than a hydroxyl group, it is preferable to include a homopolymer having a glass transition temperature Tg of 50° C. to 100° C. in order to further exhibit the effect of the present invention. Monomers with polar groups other than hydroxyl groups. The glass transition temperature Tg of the homopolymer of the monomer is preferably from 60°C to 95°C, more preferably from 70°C to 90°C.

In terms of being able to further exhibit the effects of the present invention, the glass transition temperature Tg of the homopolymer (homopolymer) in the monomer (m5) having a polar group other than the hydroxyl group is 50°C to 100°C (preferably 60°C to 95°C, more preferably 70°C to 90°C), the content ratio of monomers having polar groups other than hydroxyl groups is preferably 30% by weight to 100% by weight, more preferably 50% by weight to 100% by weight, and further Preferably it is 70% by weight to 100% by weight, particularly preferably 90% by weight to 100% by weight, most preferably 95% by weight to 100% by weight.

Here, the glass transition temperature Tg of a homopolymer (homopolymer) of a monomer (m5) having a polar group other than a hydroxyl group that may be included in the monomer component (M) may be a value recorded in a known document, For example, the values described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) can be used. In addition, when plural numerical values are described in the above-mentioned "Polymer Handbook", conventional values are adopted. For monomers (m5) having polar groups other than hydroxyl groups that are not described in the above-mentioned "Polymer Handbook", the catalog values of monomer manufacturers are adopted. Regarding the Tg of homopolymers of alkyl (meth)acrylates that are not described in the above-mentioned "Polymer Handbook" and that do not provide the catalog values of monomer manufacturers, the Tg of the homopolymer of alkyl (meth)acrylate is used from Japanese Patent Application Laid-Open No. 2007-51271 The value obtained by the recorded measurement method.

(通式(1)中，R ¹為碳數1～10之烷基，R ²為氫原子、碳數1～10之烷基或-COOR基，R為碳數1～10之烷基) [化4]

(通式(2)中，R ³為碳數1～10之伸烷基，R ⁴為碳數1～10之烷基，R ⁵為氫原子或甲基) As a monomer (m5) having a polar group other than a hydroxyl group, it is preferable to include a monomer (1) represented by the general formula (1), a monomer (2) represented by the general formula (2) and N - At least one member selected from the group consisting of vinyl-2-pyrrolidone. [Chem 3]

(In general formula (1), R ¹ is an alkyl group with 1 to 10 carbons, R ² is a hydrogen atom, an alkyl group with 1 to 10 carbons or -COOR group, R is an alkyl group with 1 to 10 carbons) [chemical 4]

(In general formula (2), ^R3 is an alkylene group with ¹ to 10 carbons, R4 is an alkyl group with ¹ to 10 carbons, and R5 is a hydrogen atom or a methyl group)

The monomer (1) represented by general formula (1) may be only 1 type, and may be 2 or more types.

The monomer (1) represented by the general formula (1) has two polymerizable double bonds at the terminal, and has a structure (C-CH ₂ -O-CH ₂ - C), and at least one of the second carbon atoms from the end of the two polymerizable double bonds at the end has an alkyl ester group (COOR ¹ group), thereby being able to promote cyclopolymerization, and to Alkyl ester groups are introduced into the structure constructed by chemical polymerization. With these features, the obtained acrylic adhesive can simultaneously exhibit better flexibility and better recovery for bending actions.

The monomer (2) represented by general formula (2) may be only 1 type, and may be 2 or more types.

The monomer (2) represented by the general formula (2) has a (meth)acrylate structure (CH ₂ =C(R ⁵ )COO-) and a carbamoyloxy structure (-O-CO-NH-) This characteristic, by virtue of these characteristics, for the obtained acrylic adhesive, it is possible to simultaneously exhibit more excellent bendability and more excellent recovery for bending action.

In the monomer (1) represented by the general formula (1), R ¹ is an alkyl group having 1 to 10 carbon atoms. In terms of being able to further exhibit the effect of the present invention, R ¹ is preferably an alkyl group having 1 to 8 carbon atoms. The alkyl group is more preferably an alkyl group having 1 to 6 carbon atoms, further preferably an alkyl group having 1 to 3 carbon atoms, particularly preferably a methyl group or an ethyl group, most preferably a methyl group.

In the monomer (1) represented by the general formula (1), R ² is a hydrogen atom, an alkyl group having 1 to 10 carbons, or a -COOR group. When R ² is an alkyl group with 1 to 10 carbons, in terms of being able to further exhibit the effect of the present invention, R ² is preferably an alkyl group with 1 to 8 carbons, more preferably an alkyl group with 1 to 6 carbons , and more preferably an alkyl group having 1 to 3 carbon atoms. When R ² is a -COOR group, R is an alkyl group with 1 to 10 carbons, and in terms of being able to further exhibit the effects of the present invention, R is preferably an alkyl group with 1 to 8 carbons, more preferably 1 carbons An alkyl group of 6 to 6, more preferably an alkyl group having 1 to 3 carbon atoms, particularly preferably a methyl group or an ethyl group, most preferably a methyl group. In terms of being able to further exhibit the effects of the present invention, R ² is preferably a hydrogen atom.

In the monomer (2) represented by the general formula (2), R ³ is an alkylene group having 1 to 10 carbon atoms, and in terms of being able to further exhibit the effect of the present invention, R ³ is preferably an alkylene group having 1 to 8 carbon atoms An alkylene group, more preferably an alkylene group with 1 to 6 carbons, more preferably an alkylene group with 1 to 3 carbons, especially a methylene group (-CH ₂ -) or an ethylene group (- CH2CH2- ₎ , most preferably ethylidene _{( -CH2CH2- )} .

In the monomer (2) represented by general formula (2), R ⁴ is an alkyl group having 1 to 10 carbon atoms, and in terms of being able to further exhibit the effect of the present invention, R ⁴ is preferably an alkyl group having 2 to 8 carbon atoms. The alkyl group is more preferably an alkyl group having 3 to 6 carbon atoms, further preferably an alkyl group having 3 to 5 carbon atoms, especially preferably a butyl group, most preferably a n-butyl group.

In the monomer (2) represented by the general formula (2), R ⁵ is a hydrogen atom or a methyl group, and R ⁵ is preferably a hydrogen atom in terms of being able to further exhibit the effects of the present invention.

In terms of being able to further exhibit the effects of the present invention, the monomer component (M) is selected from the monomer (1) represented by the general formula (1), the monomer (2) represented by the general formula (2), and N -The content rate of at least one kind from the group consisting of vinyl-2-pyrrolidone is preferably 0.01% by weight to 30% by weight, more preferably 0.05% by weight to 10% by weight, and still more preferably 0.1% by weight ~5.0% by weight, more preferably 0.3% by weight to 4.0% by weight, especially preferably 0.4% by weight to 3.5% by weight, most preferably 0.5% by weight to 3.0% by weight.

When the monomer component (M) contains the monomer (1) represented by the general formula (1), in the aspect that can further exhibit the effect of the present invention, the monomer component (M) represented by the general formula (1) The content ratio of the indicated monomer (1) is preferably 0.01% by weight to 20% by weight, more preferably 0.1% by weight to 10% by weight, further preferably 0.2% by weight to 5.0% by weight, and still more preferably 0.3% by weight % to 3.0% by weight, particularly preferably 0.4% to 2.0% by weight, most preferably 0.5% to 1.5% by weight.

When the monomer component (M) contains the monomer (2) represented by the general formula (2), in the aspect that can further exhibit the effect of the present invention, the monomer component (M) represented by the general formula (2) The content ratio of the indicated monomer (2) is preferably 0.01% by weight to 20% by weight, more preferably 0.05% by weight to 10% by weight, further preferably 0.1% by weight to 8.0% by weight, and still more preferably 1.0% by weight % to 6.0% by weight, more preferably 1.2% to 4.0% by weight, most preferably 1.5% to 3.0% by weight.

When the monomer component (M) contains N-vinyl-2-pyrrolidone, in the aspect that can further exhibit the effect of the present invention, the N-vinyl-2-pyrrolidone in the monomer component (M) The content ratio of ketone is preferably 0.01% by weight to 20% by weight, more preferably 0.05% by weight to 10% by weight, still more preferably 0.1% by weight to 5.0% by weight, still more preferably 0.2% by weight to 3.0% by weight, Most preferably, it is 0.3% by weight to 2.0% by weight, most preferably, it is 0.4% by weight to 1.5% by weight.

As a monomer (m5) having a polar group other than a hydroxyl group, in addition to the monomer (1) represented by the general formula (1), the monomer (2) represented by the general formula (2), N-vinyl-2 - other than pyrrolidone, for example: carboxyl group-containing monomers, nitrogen-containing monomers other than N-vinyl-2-pyrrolidone, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, cyanide-containing monomers, monomers containing acid anhydride groups, vinyl esters (such as vinyl acetate (VAc), vinyl propionate, vinyl laurate), aromatic vinyl compounds, monomers containing amide groups, amide rings Oxygen monomers, (meth)acryloyl methionine, vinyl ethers.

Examples of carboxyl group-containing monomers include acrylic acid (AA), methacrylic acid (MAA), carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, Malic acid, crotonic acid, methacrylic acid.

Nitrogen-containing monomers other than N-vinyl-2-pyrrolidone include, for example, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, and vinylpiperidone. , Vinyl pyrroline, vinyl pyrrole, vinyl imidazole, vinyl oxazole, vinyl phospholine, (meth)acryloyl 𠰌line, N-vinyl carboxamides, N-vinyl caprolactam Nitrogen-containing vinyl monomers such as acrylonitrile, methacrylonitrile and other cyano-containing acrylic monomers.

The monomer component (M) preferably contains an alkyl (meth)acrylate. The alkyl group in the ester part is preferably an alkyl group having 1 to 16 carbon atoms. The alkyl group of the ester moiety mentioned here does not include the alkyl group containing a polar group such as a hydroxyl group.

Alkyl (meth)acrylate may be only 1 type, and may be 2 or more types.

At the point where the effects of the present invention can be further exhibited, the content ratio of the alkyl (meth)acrylate in the monomer component (M) is preferably from 50% by weight to 99% by weight, more preferably from 70% by weight to 98% by weight %, more preferably 80% by weight to 97% by weight, particularly preferably 85% by weight to 96% by weight, most preferably 90% by weight to 96% by weight.

Regarding the alkyl (meth)acrylate, any suitable alkyl (meth)acrylate can be employed within the range not impairing the effect of the present invention. As such an alkyl (meth)acrylate, for example, a compound represented by the following formula (1) can be preferably used. CH ₂ =C(R ¹ )COOR ² (1)

Here, R ¹ in the above formula (1) is a hydrogen atom or a methyl group, and R ² is an alkyl group having 1 to 20 carbon atoms.

In terms of being able to further exhibit the effect of the present invention, R is preferably an alkyl group with 1 to 16 carbons, more preferably an alkyl group with ² to 14 carbons, and even more preferably an alkyl group with 4 to 14 carbons, Especially preferred is an alkyl group having 4 to 12 carbon atoms.

The above-mentioned alkyl group is preferably a chain alkyl group at the point that the effect of the present invention can be further exhibited. Here, the term "chain" includes both linear and branched chains.

Examples of alkyl (meth)acrylates in which R is a chain alkyl group having ¹ to 20 carbons include: methyl (meth)acrylate, ethyl (meth)acrylate, (meth)acrylic acid Propyl ester, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, second butyl (meth)acrylate, amyl (meth)acrylate, (meth)acrylate base) isopentyl acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate ester, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, (meth)acrylate ) lauryl acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, ( Heptadecyl (meth)acrylate, Stearyl (meth)acrylate, Isostearyl (meth)acrylate, Nonadecyl (meth)acrylate, Eicosane (meth)acrylate base ester.

In terms of being able to further exhibit the effect of the present invention, the glass transition temperature Tg of the homopolymer (homopolymer) of alkyl (meth)acrylate that may be included in the monomer component (M) is preferably -10°C or less, more preferably Preferably it is -12°C or lower, more preferably -15°C or lower, especially preferably -18°C or lower, most preferably -20°C or lower. The lower limit of the glass transition temperature Tg is preferably -80°C or higher. The glass transition temperature Tg of the homopolymer (homopolymer) of the alkyl (meth)acrylate that may be included in the monomer component (M) may affect the adhesion and bending properties of the acrylic polymer (P). By using an alkyl (meth)acrylate whose glass transition temperature Tg of a homopolymer (homopolymer) is within the above-mentioned range as an alkyl (meth)acrylate that can be contained in the monomer component (M), it is possible to appropriately adjust The adhesiveness and elasticity of the acrylic polymer (P) can further exhibit the effect of the present invention.

Here, the glass transition temperature Tg of the homopolymer (homopolymer) of alkyl (meth)acrylate that may be contained in the monomer component (M) is different from the above-mentioned monomer (m5) having a polar group other than a hydroxyl group. Likewise, values described in known materials, for example, values described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) can be used. In addition, when plural numerical values are described in the above-mentioned "Polymer Handbook", conventional values are adopted. Regarding the alkyl (meth)acrylates not listed in the above-mentioned "Polymer Handbook", the catalog value of the monomer manufacturer is used. Regarding the Tg of homopolymers of alkyl (meth)acrylates that are not described in the above-mentioned "Polymer Handbook" and that do not provide the catalog values of monomer manufacturers, the Tg of the homopolymer of alkyl (meth)acrylate is used from Japanese Patent Application Laid-Open No. 2007-51271 The value obtained by the recorded measurement method.

Representative examples of the glass transition temperature Tg of the homopolymer (homopolymer) of the alkyl (meth)acrylate that may be contained in the monomer component (M) are as follows, for example. 2-ethylhexyl acrylate (2EHA): -70°C Lauryl Acrylate (LA): -23°C n-Butyl Acrylate (BA): -55°C

In terms of being able to further exhibit the effects of the present invention, the monomer component (M) is preferably a (meth)acrylic alkylene having a glass transition temperature Tg of a homopolymer (homopolymer) in the range of -80°C to -60°C. base ester (m1) as an alkyl (meth)acrylate. When the monomer component (M) contains an alkyl (meth)acrylate (m1), the alkyl (meth)acrylate in the monomer component (M) can further exhibit the effect of the present invention The content ratio of (m1) is preferably 40% by weight to 99% by weight, more preferably 45% by weight to 90% by weight, still more preferably 50% by weight to 80% by weight, particularly preferably 55% by weight to 75% by weight , optimally 60% by weight to 70% by weight.

As mentioned above, the glass transition temperature Tg of the homopolymer (homopolymer) of alkyl (meth)acrylate that may be included in the monomer component (M) may affect the adhesive properties and bending properties of the acrylic polymer (P) . Therefore, the (meth)acrylic acid that can be contained in the monomer component (M) is used by adjusting the content ratio of the alkyl (meth)acrylate (m1) in the monomer component (M) to the above range. Alkyl esters can appropriately adjust the adhesiveness and elasticity of the acrylic polymer (P), and can further exhibit the effects of the present invention.

As the above-mentioned alkyl (meth)acrylate (m1), 2-ethylhexyl acrylate (2EHA) (the glass transition temperature Tg of its homopolymer (homopolymer)=-70 degreeC) is mentioned, for example.

In terms of being able to further exhibit the effect of the present invention, the monomer component (M) is preferably a (meth)acrylic alkylene having a glass transition temperature Tg of a homopolymer (homopolymer) in the range of -40°C to -10°C. base ester (m2) as an alkyl (meth)acrylate. When the monomer component (M) contains an alkyl (meth)acrylate (m2), in the aspect that can further exhibit the effects of the present invention, the alkyl (meth)acrylate in the monomer component (M) The content ratio of (m2) is preferably 5% by weight to 50% by weight, more preferably 7% by weight to 40% by weight, further preferably 10% by weight to 30% by weight, particularly preferably 13% by weight to 25% by weight , optimally 15% by weight to 22% by weight.

As mentioned above, the glass transition temperature Tg of the homopolymer (homopolymer) of alkyl (meth)acrylate that may be included in the monomer component (M) may affect the adhesiveness and elasticity of the acrylic polymer (P). Then, the (meth)acrylic acid that can be contained in the monomer component (M) is used by adjusting the content ratio of the alkyl (meth)acrylate (m2) in the monomer component (M) to the above range. Alkyl esters can appropriately adjust the adhesiveness and elasticity of the acrylic polymer (P), and can further exhibit the effects of the present invention.

As the above-mentioned alkyl (meth)acrylate (m2), for example, lauryl acrylate (LA) (the glass transition temperature Tg of its homopolymer (homopolymer) = -23° C.) can be mentioned, for example.

In terms of being able to further exhibit the effects of the present invention, the monomer component (M) is preferably a homopolymer (homopolymer) whose glass transition temperature Tg is in a range exceeding -60°C and not reaching -40°C (methyl ) Alkyl acrylate (m3) as alkyl (meth)acrylate. When the monomer component (M) contains an alkyl (meth)acrylate (m3), in the aspect that can further exhibit the effect of the present invention, the alkyl (meth)acrylate in the monomer component (M) The content ratio of (m3) is preferably 0.1% by weight to 30% by weight, more preferably 1% by weight to 20% by weight, still more preferably 3% by weight to 15% by weight, particularly preferably 4% by weight to 13% by weight , most preferably 5% by weight to 10% by weight.

As mentioned above, the glass transition temperature Tg of the homopolymer (homopolymer) of alkyl (meth)acrylate that may be included in the monomer component (M) may affect the adhesiveness and elasticity of the acrylic polymer (P). Then, by adjusting the content ratio of the alkyl (meth)acrylate (m3) in the monomer component (M) to the above range, it can be used as (meth)acrylic acid that can be contained in the monomer component (M) Alkyl esters can appropriately adjust the adhesiveness and elasticity of the acrylic polymer (P), and can further exhibit the effects of the present invention.

As the above-mentioned alkyl (meth)acrylate (m3), n-butyl acrylate (BA) (the glass transition temperature Tg of its homopolymer (homopolymer)=-55 degreeC) is mentioned, for example.

In terms of being able to further demonstrate the effect of the present invention, the monomer component (M) preferably comprises a group selected from alkyl (meth)acrylate (m1), alkyl (meth)acrylate (m2), (meth)acrylate base) at least one of the group consisting of alkyl (m3) acrylates, more preferably at least one selected from the group consisting of alkyl (meth)acrylates (m1), alkyl (meth)acrylates (m2), ( At least two of the group consisting of alkyl meth)acrylates (m3), more preferably including alkyl (meth)acrylates (m1), alkyl (meth)acrylates (m2), ( Alkyl meth)acrylates (m3) all.

In terms of being able to further exhibit the effect of the present invention, representatively, the monomer component (M) is preferably selected from the group consisting of 2-ethylhexyl acrylate, lauryl acrylate, and n-butyl acrylate. At least one, more preferably at least two selected from the group consisting of 2-ethylhexyl acrylate, lauryl acrylate, and n-butyl acrylate, and more preferably 2-ethylhexyl acrylate, acrylic acid Lauryl, n-butyl acrylate all.

The monomer component (M) preferably contains a hydroxyl group-containing monomer (m4). Only 1 type may be sufficient as a hydroxyl group containing monomer (m4), and 2 or more types may be sufficient as it.

In terms of being able to further exhibit the effects of the present invention, the glass transition temperature Tg of the homopolymer (homopolymer) of the hydroxyl-containing monomer (m4) that may be included in the monomer component (M) is preferably -10°C or less, more preferably It is -15°C or lower, more preferably -20°C or lower, particularly preferably -25°C or lower, most preferably -30°C or lower. The lower limit of the glass transition temperature Tg is preferably -80°C or higher. The glass transition temperature Tg of the homopolymer (homopolymer) of the hydroxyl-containing monomer (m4) that may be contained in the monomer component (M) may affect the adhesiveness and elasticity of the acrylic polymer (P). By adopting the hydroxyl group-containing monomer (m4) whose glass transition temperature Tg of the homopolymer (homopolymer) is in the above-mentioned range as the hydroxyl group-containing monomer (m4) that can be included in the monomer component (M), it is possible to properly adjust the acrylic system. The adhesiveness and elasticity of the polymer (P) can further demonstrate the effect of the present invention.

Here, the glass transition temperature Tg of the homopolymer (homopolymer) of the hydroxyl group-containing monomer (m4) that may be included in the monomer component (M) is different from the above-mentioned monomer (m5) having a polar group other than the hydroxyl group or As for the above-mentioned alkyl (meth)acrylate, values described in known materials, for example, values described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) can be used. In addition, when plural numerical values are described in the above-mentioned "Polymer Handbook", conventional values are adopted. For hydroxyl-containing monomers (m4) that are not described in the above-mentioned "Polymer Handbook", the catalog values of monomer manufacturers are used. Regarding the Tg of the homopolymer of the hydroxyl group-containing monomer (m4) that is not described in the above-mentioned "Polymer Handbook" and does not provide the catalog value of the monomer manufacturer, the Tg described in JP-A-2007-51271 is used The value obtained by the measurement method.

Representative examples of the glass transition temperature Tg of the homopolymer (homopolymer) of the hydroxyl group-containing monomer (m4) that may be contained in the monomer component (M) are as follows, for example. 2-Hydroxyethyl acrylate: -15°C 4-Hydroxybutyl acrylate: -40°C

When the monomer component (M) contains a hydroxyl group-containing monomer (m4), the content ratio of the hydroxyl group-containing monomer (m4) in the monomer component (M) is preferable in terms of further exhibiting the effect of the present invention 0.01% by weight to 30% by weight, more preferably 0.1% by weight to 20% by weight, more preferably 0.5% by weight to 15% by weight, most preferably 1% by weight to 10% by weight, most preferably 2% by weight to 5% by weight.

Examples of the hydroxyl group-containing monomer (m4) include: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (meth)acrylate ) Hydroxyalkyl (meth)acrylates such as 2-hydroxybutyl acrylate, 4-hydroxybutyl (meth)acrylate; polypropylene glycol mono(meth)acrylate; N-hydroxyethyl (meth)acrylic acid amine.

In terms of being able to further exhibit the effects of the present invention, the hydroxyl-containing monomer (m4) preferably includes a hydroxyalkyl (meth)acrylate, more preferably a straight-chain alkane having an alkyl moiety of 2 to 4 carbons. Hydroxyalkyl (meth)acrylates. As the hydroxyalkyl (meth)acrylate, for example, 2-hydroxyethyl acrylate (HEA) and 4-hydroxybutyl acrylate (4HBA) can be mentioned, and acrylic acid is preferable because it can further exhibit the effects of the present invention. 4-Hydroxybutyl ester.

In terms of being able to further demonstrate the effect of the present invention, the monomer component (M) preferably comprises a group selected from alkyl (meth)acrylate (m1), alkyl (meth)acrylate (m2), (meth)acrylate base) at least one of the group consisting of alkyl acrylate (m3) and a hydroxyl group-containing monomer (m4), more preferably comprising the group consisting of alkyl (meth)acrylate (m1), At least two of the group consisting of alkyl ester (m2), alkyl (meth)acrylate (m3) and hydroxyl-containing monomer (m4), and preferably include alkyl (meth)acrylate ( All of m1), alkyl (meth)acrylate (m2), alkyl (meth)acrylate (m3), and hydroxyl-containing monomer (m4).

In terms of being able to further exhibit the effect of the present invention, representatively, the monomer component (M) is preferably selected from the group consisting of 2-ethylhexyl acrylate, lauryl acrylate, and n-butyl acrylate. At least 1 kind and a hydroxyl-containing monomer (m4), more preferably at least 2 kinds selected from the group consisting of 2-ethylhexyl acrylate, lauryl acrylate, and n-butyl acrylate and a hydroxyl-containing monomer (m4 ), and further preferably include all of 2-ethylhexyl acrylate, lauryl acrylate, n-butyl acrylate and hydroxyl-containing monomers (m4).

In terms of further exhibiting the effects of the present invention, the alkyl (meth)acrylate (m1), alkyl (meth)acrylate (m2), alkyl (meth)acrylate in the monomer component (M) The content ratio of the total amount of the base ester (m3) and the hydroxyl group-containing monomer (m4) is preferably 60% by weight to 99.9% by weight, more preferably 70% by weight to 99.8% by weight, still more preferably 80% by weight to 99.7% by weight % by weight, preferably 90% by weight to 99.6% by weight, most preferably 95% by weight to 99.5% by weight.

The monomer component (M) may also contain the above-mentioned monomer (m5) having a polar group other than the hydroxyl group, the above-mentioned alkyl (meth)acrylate, and the above-mentioned hydroxyl-containing monomer within the range that does not impair the effect of the present invention. Other monomers other than (m4). Other monomers can be used, for example, to adjust the glass transition temperature (Tg) of the acrylic polymer (P), adjust the adhesive properties, and the like. The other monomer may be only 1 type, and may be 2 or more types.

The content ratio of other monomers in the monomer component (M) is preferably at most 20% by weight, more preferably at most 10% by weight, still more preferably at most 5% by weight, especially preferably at most 3% by weight, most preferably at most 3% by weight 1% by weight or less.

As a method of obtaining the acrylic polymer (P), for example, various polymerization methods known as synthesis methods of acrylic polymers, such as solution polymerization, emulsion polymerization, block polymerization, and suspension polymerization, can be suitably used. Among these polymerization methods, a solution polymerization method can be preferably used. As a method for supplying monomers during solution polymerization, a one-time addition system for supplying the entire amount of monomer components at once, a continuous supply (dropping) system, a batch supply (dropping) system, etc. can be suitably employed. The polymerization temperature can be appropriately selected according to the type of monomer and solvent used, the type of polymerization initiator, etc., and is preferably 20°C or higher, more preferably 30°C or higher, further preferably 40°C or higher, more preferably 170°C or lower, more preferably 160°C or lower, still more preferably 140°C or lower. As a method for obtaining an acrylic polymer, photopolymerization by irradiating light such as UV (ultraviolet) (typically, in the presence of a photopolymerization initiator), or irradiating β-rays, γ-rays, etc. Active energy ray irradiation polymerization such as radiation polymerization by radiation.

As a solvent used for solution polymerization (polymerization solvent), it can select suitably from arbitrary appropriate organic solvents. For example, aromatic compounds (typically aromatic hydrocarbons) such as toluene, acetates such as ethyl acetate, aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane, and the like may be mentioned.

The initiator used for polymerization (polymerization initiator) can be appropriately selected from any appropriate polymerization initiators according to the type of polymerization method. The polymerization initiator may be only 1 type, and may be 2 or more types.

Examples of polymerization initiators include: 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis Dimethyl (2-methylpropionate), 4,4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2'-azobis(2-amidinopropane) Dihydrochloride, 2,2'-Azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-Azobis(2-methyl Disulfate, 2,2'-Azobis(N,N'-Dimethylisobutylamidine), 2,2'-Azobis[N-(2-carboxyethyl)- Azo-based initiators such as 2-methylpropionamidine]hydrate (VA-057, manufactured by Wako Pure Chemical Industries, Ltd.); persulfates such as potassium persulfate and ammonium persulfate, di(2-ethyl peroxydicarbonate) Hexyl) ester, di(4-tert-butylcyclohexyl) peroxydicarbonate, di-butyl peroxydicarbonate, tertiary butyl peroxyneodecanoate, tertiary peroxypivalic acid Hexyl ester, tertiary butyl peroxypivalate, dilauroyl peroxide, dioctyl peroxide, 1,1,3,3-tetramethylbutyl peroxide, 2-ethylhexanoate, peroxide Bis(4-methylbenzoyl), dibenzoyl peroxide, tert-butyl peroxyisobutyrate, 1,1-di(tert-hexylperoxy)cyclohexane, tert-butylperoxy Peroxide-based initiators such as hydrogen peroxide and hydrogen peroxide; combinations of persulfate and sodium bisulfite, combinations of peroxide and sodium ascorbate, etc. Initiator; substituted ethane-based initiators such as phenyl substituted ethane; aromatic carbonyl compounds.

The usage-amount of a polymerization initiator is preferably 0.005-1 weight part with respect to 100 weight part of monomer components (M), More preferably, it is 0.01-1 weight part.

For the polymerization, any other appropriate additives may also be contained within the range not impairing the effect of the present invention.

"Oligomer" The acrylic adhesive composition according to the embodiment of the present invention preferably contains an oligomer. The oligomer may be only 1 type, and may be 2 or more types. When the acrylic adhesive composition of embodiment of this invention contains an oligomer, the effect of this invention can be exhibited further.

The weight average molecular weight Mw of the oligomer is preferably from 1,000 to 30,000, more preferably from 1,500 to 10,000, still more preferably from 2,000 to 8,000, especially preferably from 2,000 to 5,000. By using the oligomer of such a weight average molecular weight Mw, the adhesiveness and elasticity of an acrylic adhesive sheet can be improved.

As an oligomer, an acrylic oligomer is preferable at the point which has easy affinity with an acrylic polymer.

The glass transition temperature Tg of the acrylic oligomer is preferably at least 20°C, more preferably at least 40°C, still more preferably at least 60°C, particularly preferably at least 80°C, most preferably at least 100°C. The upper limit of the glass transition temperature Tg of the acrylic oligomer is preferably at most 200°C, more preferably at most 180°C, still more preferably at most 160°C.

The glass transition temperature Tg of the acrylic oligomer refers to the Tg of the homopolymer (homopolymer) based on the constituent monomers and the weight fraction of the monomer (copolymerization ratio on a weight basis), calculated according to the Fox formula value. As shown below, Fox's formula is a relationship between the Tg of a copolymer and the glass transition temperature Tgi of a homopolymer obtained by homopolymerizing the monomers constituting the copolymer. 1/Tg＝Σ(Wi/Tgi)

In the above Fox formula, Tg represents the glass transition temperature of the copolymer (unit: K), Wi represents the weight fraction of monomer i in the copolymer (copolymerization ratio on a weight basis), and Tgi represents the homopolymer of monomer i The glass transition temperature (unit: K). As Tg of the homopolymer, values described in known materials, for example, values described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) can be used. When plural numerical values are described in the above-mentioned "Polymer Handbook", conventional values are adopted. For monomers that are not listed in the "Polymer Handbook" above, the catalog values of monomer manufacturers are used. The Tg of homopolymers of monomers that are not described in the above-mentioned "Polymer Handbook" and that do not provide the catalog values of monomer manufacturers is obtained using the measurement method described in Japanese Patent Application Laid-Open No. 2007-51271 value.

The acrylic oligomer contains an alicyclic alkyl (meth)acrylate as a main constituent monomer component. The alicyclic alkyl (meth)acrylate may be only 1 type, or may be 2 or more types.

Examples of the alicyclic alkyl (meth)acrylate include: cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, (meth)acrylic acid Cycloalkyl (meth)acrylates such as cyclooctyl esters; (meth)acrylates with bicyclic aliphatic hydrocarbon rings such as iso(meth)acrylates; dicyclopentanyl (meth)acrylates, Dicyclopentyloxyethyl (meth)acrylate, Tricyclopentyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate (Meth)acrylic acid esters having three or more aliphatic hydrocarbon rings, such as ester, 2-ethyl-2-adamantyl (meth)acrylate, etc.

As the alicyclic alkyl (meth)acrylate, dicyclopentyl acrylate, dicyclopentyl methacrylate, cyclohexyl acrylate, methacrylate ring hexyl ester.

In terms of further exhibiting the effect of the present invention, the content ratio of the alkyl alicyclic (meth)acrylate to the total amount of monomer components constituting the acrylic oligomer is preferably 10% by weight to 99% by weight, More preferably, it is 30 weight% - 98 weight%, More preferably, it is 40 weight% - 97 weight%, Most preferably, it is 50 weight% - 96 weight%.

The acrylic oligomer may contain a chain alkyl (meth)acrylate having a chain alkyl group as a constituent monomer component. The chain alkyl (meth)acrylate which has a chain alkyl group may be only 1 type, and may be 2 or more types. Here, the term "chain" includes both linear and branched chains.

The chain alkyl (meth)acrylate is preferably a chain alkyl (meth)acrylate having a chain alkyl group having 1 to 20 carbon atoms, for example, methyl (meth)acrylate , Ethyl (meth)acrylate, Propyl (meth)acrylate, Isopropyl (meth)acrylate, n-Butyl (meth)acrylate, Isobutyl (meth)acrylate, No. Dibutyl, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, ( Octyl methacrylate, Isooctyl (meth)acrylate, Nonyl (meth)acrylate, Isononyl (meth)acrylate, Decyl (meth)acrylate, Isodecyl (meth)acrylate, Undecyl (meth)acrylate, Lauryl (meth)acrylate, Tridecyl (meth)acrylate, Myristyl (meth)acrylate, Pentadecyl (meth)acrylate ester, cetyl (meth)acrylate, heptadecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, (meth)acrylic acid Nonadecyl ester, eicosyl (meth)acrylate.

As the chain alkyl (meth)acrylate, methyl methacrylate is preferable at the point that the effect of the present invention can be further exhibited.

In terms of further exhibiting the effect of the present invention, the content ratio of the chain alkyl (meth)acrylate to the total amount of monomer components constituting the acrylic oligomer is preferably 10% by weight to 90% by weight, and more preferably Preferably, it is 20 weight% - 80 weight%, More preferably, it is 30 weight% - 70 weight%.

The acrylic oligomer may contain (meth)acrylic acid as a constituent monomer component. (Meth)acrylic acid may be only 1 type, and may be 2 or more types.

As (meth)acrylic acid, acrylic acid is preferable at the point which can express the effect of this invention further.

The content ratio of (meth)acrylic acid to the total amount of monomer components constituting the acrylic oligomer is preferably 0.1% by weight to 20% by weight, more preferably 1% by weight, so that the effect of the present invention can be further exhibited. ~10% by weight, more preferably 3% by weight to 7% by weight.

Oligomers are obtained by polymerizing constituent monomer components by various polymerization methods. When the oligomer is polymerized, any appropriate additive can be used within the range not impairing the effects of the present invention. As such an additive, a polymerization initiator and a chain transfer agent are mentioned, for example.

In terms of further exhibiting the effect of the present invention, the content ratio of the oligomer in the acrylic adhesive composition is preferably 0.1 to 6.5 parts by weight, more preferably 0.5 parts by weight to 5.5 parts by weight, more preferably 1.0 parts by weight to 4.5 parts by weight, more preferably 1.0 parts by weight to 4.0 parts by weight, even more preferably 1.0 parts by weight to 3.5 parts by weight, especially preferably 1.0 parts by weight to 3.0 parts by weight, preferably 1.5 to 2.5 parts by weight.

"Crosslinking agent" The acrylic adhesive composition according to the embodiment of the present invention may also contain a crosslinking agent. Only one type of crosslinking agent may be used, or two or more types may be used.

By using a crosslinking agent, moderate cohesion can be imparted to the acrylic adhesive. The crosslinking agent may be contained in the acrylic adhesive in a form after a crosslinking reaction, a form before a crosslinking reaction, a form in which a part of the crosslinking reaction has undergone a crosslinking reaction, an intermediate form or a composite form thereof, or the like. The cross-linking agent is typically contained in the acrylic adhesive in the form of cross-linking reaction.

In order to further exhibit the effect of the present invention, the content ratio of the crosslinking agent in the acrylic adhesive composition is preferably 0.005 to 10 parts by weight, more preferably 100 parts by weight of the acrylic polymer (P). Preferably it is 0.01 to 7 parts by weight, more preferably 0.01 to 5 parts by weight, more preferably 0.01 to 1 part by weight, even more preferably 0.01 to 0.5 parts by weight, especially preferably 0.01 parts by weight Parts by weight to 0.35 parts by weight, most preferably 0.01 parts by weight to 0.1 parts by weight.

Examples of crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, silicone crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, and silane crosslinking agents. Crosslinking agents such as crosslinking agents, alkyl etherified melamine crosslinking agents, metal chelate crosslinking agents, peroxides, etc., are preferably isocyanate crosslinking agents, cyclic An oxygen-based crosslinking agent and a peroxide, more preferably an isocyanate-based crosslinking agent and a peroxide.

As the isocyanate-based crosslinking agent, a compound having two or more isocyanate groups (including isocyanate-regenerating polar groups in which isocyanate groups are temporarily protected by blocking agents or polymerization, etc.) can be used in one molecule. Examples of the isocyanate-based crosslinking agent include aromatic isocyanates such as toluene diisocyanate and xylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; and aliphatic isocyanates such as hexamethylene diisocyanate.

As the isocyanate-based crosslinking agent, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; cyclopentyl diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, etc. Alicyclic cyclohexylene diisocyanate such as isocyanate; 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, polymethylene polyphenylisocyanate and other aromatics Diisocyanates; trimethylolpropane/toluene diisocyanate trimer adduct (for example, manufactured by Toso Corporation, trade name Coronate L), trimethylolpropane/hexamethylene diisocyanate trimer adduct (for example, manufactured by Toso Corporation, trade name: Coronate HL), isocyanurate body of hexamethylene diisocyanate (for example, manufactured by Toso Corporation, trade name: Coronate HX) and other isocyanate adducts; benzene Trimethylolpropane adduct of dimethyl diisocyanate (for example, manufactured by Mitsui Chemicals, trade name: Takenate D110N), trimethylolpropane adduct of xylylene diisocyanate (for example, Mitsui Chemicals Manufactured, trade name: Takenate D120N), trimethylolpropane adduct of isophorone diisocyanate (for example, manufactured by Mitsui Chemicals, trade name: Takenate D140N), trimethylol of hexamethylene diisocyanate Propane adducts (for example, manufactured by Mitsui Chemicals, trade name: Takenate D160N); polyether polyisocyanate, polyester polyisocyanate, and their adducts with various polyols; bonded by isocyanurate , biuret linkage, allophanate linkage and other multifunctional polyisocyanates. Among these, aromatic isocyanate and alicyclic isocyanate are preferable in terms of both deformability and cohesion in a good balance.

As an epoxy-type crosslinking agent, the polyfunctional epoxy compound which has 2 or more epoxy groups in 1 molecule can be used. Examples of epoxy-based crosslinking agents include N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidylaniline, 1,3-bis(N,N- Diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol Diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylol Diglycidyl adipate, diglycidyl adipate, diglycidyl phthalate, tris(2-hydroxyethyl) isocyanurate triglycidyl ether, resorcinol diglycidyl ether, bis Phenol-S-diglycidyl ether, an epoxy resin with two or more epoxy groups in the molecule. As a commercial item of an epoxy-type crosslinking agent, the products called "Tetrad C" and "Tetrad X" by Mitsubishi Gas Chemical Co., Ltd. are mentioned, for example.

Examples of peroxides include: dibenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, di-tert-butyl peroxy-3,3,5- Trimethylcyclohexane, tert-butyl hydroperoxide, tert-butyl cumyl peroxide, 2,5-dimethyl-2,5-di(tert-butyl peroxy)hexane Alkyne-3, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, 2,5-dimethyl-2,5-mono(tert-butylperoxy) Hexane, α,α'-bis(tert-butylperoxy-m-isopropyl)benzene, bis(2-ethylhexyl) peroxydicarbonate, bis(4-tert-butyl peroxydicarbonate) Cyclohexyl) ester, di-butyl peroxydicarbonate, tertiary butyl peroxyneodecanoate, tertiary hexyl peroxypivalate, tertiary butyl peroxypivalate, dibutyl peroxide Lauryl, Di-n-octyl peroxide, 1,1,3,3-Tetramethylbutyl peroxide, Di(4-methylbenzoyl) peroxide, Isobutyric peroxide Tertiary butyl ester, 1,1-di(tertiary hexylperoxy)cyclohexane, 1,1-bis(tertiary butylperoxy)cyclohexane, 2-ethylhexyl peroxycarbonate Butyl peroxide, tertiary amyl isopropyl carbonate, 3,5,5-trimethylhexyl peroxide, tert-butyl peroxide 2-hexanoate, tertiary butyl peroxypivalate, peroxide Oxidation of tertiary hexyl pivalate. As a commercially available product of a peroxide, the product called "Nyper BMT" series by the NOF Corporation can be mentioned, for example.

《Adhesion Imparting Resin》 The acrylic adhesive composition according to the embodiment of the present invention may also contain an adhesion-imparting resin to adjust adhesive properties, bending properties, and the like. Only 1 type may be sufficient as tackifier resin, and 2 or more types may be sufficient as it.

Examples of tackifying resins include rosin-based tackifying resins, terpene-based tackifying resins, hydrocarbon-based tackifying resins, epoxy-based tackifying resins, polyamide-based tackifying resins, elastic-based tackifying resins, Phenolic tackifying resin, ketone tackifying resin.

In order to further exhibit the effects of the present invention, the amount of the tackifying resin used is preferably 5 to 70 parts by weight, more preferably 10 to 60 parts by weight, based on 100 parts by weight of the acrylic polymer (P). parts, more preferably 15 to 50 parts by weight, more preferably 20 to 45 parts by weight, particularly preferably 25 to 40 parts by weight, most preferably 25 to 35 parts by weight.

It is preferable that the tackiness imparting resin contains tackiness imparting resin TL whose softening point is less than 105 degreeC at the point which can express the effect of this invention further. The tack-imparting resin TL can effectively help improve the deformability of the adhesive layer in the plane direction (shear direction). From the viewpoint of obtaining a higher deformability-enhancing effect, the softening point of the tackifying resin used as the tackifying resin TL is preferably 50°C to 103°C, more preferably 60°C to 100°C, and still more preferably 65°C to 95°C, especially 70°C to 90°C, most preferably 75°C to 85°C.

The softening point of the tack-imparting resin is defined as a value measured based on the softening point test method (ring and ball method) specified in JIS K5902 and JIS K2207. Specifically, the sample is rapidly melted at the lowest possible temperature and filled into a ring placed on a flat metal plate, taking care not to bubble. After cooling, use a slightly heated knife to cut off the portion raised from the flat surface on the upper end of the containment ring. Next, put the holder (ring table) in a glass container (heating bath) with a diameter of 85 mm or more and a height of 127 mm or more, and inject glycerin until the depth becomes 90 mm or more. Next, immerse the steel ball (9.5 mm in diameter, 3.5 g in weight) and the ring filled with the sample into glycerin without contacting each other, and keep the temperature of glycerin at 20°C±5°C for 15 minutes. Next, place the steel ball in the center of the surface of the sample in the ring, and place it in a fixed position on the holder. Next, keep the distance from the upper end of the ring to the glycerol surface at 50 mm, place a thermometer so that the center of the mercury bulb of the thermometer is at the same height as the center of the ring, and heat the container. The flame of the Bunsen burner used for heating should be located in the middle of the center of the bottom of the container and the edge, and it should be heated evenly. Furthermore, the rate of rise of the bath temperature after reaching 40°C after the start of heating must be 5.0±0.5°C per minute. The sample gradually softens and flows down from the ring, and the temperature when it finally touches the bottom plate is read as the softening point. The measurement of softening point was carried out more than 2 times at the same time, and the average value was taken.

The amount of tackifying resin TL used is preferably 5 to 50 parts by weight, more preferably 10 parts by weight, based on 100 parts by weight of the acrylic polymer (P) so that the effects of the present invention can be further exhibited. ∼45 parts by weight, more preferably 15 parts by weight to 40 parts by weight, especially preferably 20 parts by weight to 35 parts by weight, most preferably 25 parts by weight to 32 parts by weight.

As the tackifier resin TL, one or two or more kinds appropriately selected from those whose softening point is less than 105° C. among the tackifier resins exemplified above can be used. Tack-providing resin TL preferably contains rosin-based resin.

About the rosin-type resin which can be used preferably as tackiness imparting resin TL, rosin esters, such as unmodified rosin ester and modified rosin ester, etc. are mentioned, for example. As a modified rosin ester, hydrogenated rosin ester is mentioned, for example.

It is preferable that tackiness imparting resin TL contains hydrogenated rosin ester at the point which can express the effect of this invention further. Regarding the hydrogenated rosin ester, in order to further exhibit the effect of the present invention, the softening point is preferably less than 105°C, more preferably 50°C to 100°C, further preferably 60°C to 90°C, particularly preferably 70°C ~85°C, the best is 75°C~85°C.

Tack-providing resin TL may contain non-hydrogenated rosin ester. Here, the term "non-hydrogenated rosin ester" is a concept that collectively refers to those other than hydrogenated rosin esters among the above-mentioned rosin esters. Examples of non-hydrogenated rosin esters include unmodified rosin esters, disproportionated rosin esters, and polymerized rosin esters.

As a non-hydrogenated rosin ester, in order to further exhibit the effects of the present invention, the softening point is preferably less than 105°C, more preferably 50°C to 100°C, further preferably 60°C to 90°C, and especially preferably 70°C. ℃～85℃, the best is 75℃～85℃.

The tack-imparting resin TL may contain other tack-imparting resins other than the rosin-based resin. As other tackifier resins, one or two or more kinds appropriately selected from those whose softening point is less than 105° C. among the tackifier resins exemplified above can be used. The tack-imparting resin TL may contain, for example, a rosin-based resin and a terpene resin.

In terms of further exhibiting the effect of the present invention, the content ratio of the rosin-based resin in the entire tack-imparting resin TL is preferably more than 50% by weight, more preferably 55% by weight to 100% by weight, and still more preferably 60% by weight. % by weight to 99% by weight, particularly preferably 65% by weight to 97% by weight, most preferably 75% by weight to 97% by weight.

In terms of further exhibiting the effects of the present invention, the tackifying resin may include a combination of tackifying resin TL and tackifying resin TH having a softening point of 105° C. or higher (preferably 105° C. to 170° C.).

As the tackifier resin TH, one or two or more kinds appropriately selected from the tackifier resins exemplified above having a softening point of 105° C. or higher can be used. The tackifier resin TH may contain at least one selected from rosin-based tackifier resins (eg, rosin esters) and terpene-based tackifier resins (eg, terpene phenol resins).

"Other Ingredients" The acrylic adhesive composition according to the embodiment of the present invention may also contain a leveling agent, a crosslinking aid, a plasticizer, a softener, a filler, an antistatic agent, an antiaging agent, an ultraviolet absorber, an antioxidant, Light stabilizers, cross-linking catalysts, cross-linking retarders and other common additives in the field of adhesives. These various additives can be conventionally used conventionally known ones.

As a crosslinking catalyst, iron triacetylacetonate, tetra-n-butyl titanate, tetraisopropyl titanate, butyltin oxide, dibutyltin dilaurate, etc. are mentioned, for example. As the crosslinking retarder, for example, a compound capable of producing keto-enol tautomerism can be exemplified. Specifically, for example, β-diketones such as acetylacetone and 2,4-hexanedione can be exemplified; Acetyl acetates such as methyl acetylacetate and ethyl acetylacetate; propionyl acetates such as ethyl propionyl acetate; isobutyryl acetates such as ethyl isobutyryl acetate; methyl malonate, propionyl Malonic acid esters such as ethyl diacid, etc.

"Adhesive Film" The adhesive film which concerns on embodiment of this invention has the adhesive agent layer containing the acrylic adhesive agent sheet which concerns on embodiment of this invention.

The adhesive film according to the embodiment of the present invention may be a substrate-free film consisting only of an adhesive layer, or may be a substrate-attached film having a substrate layer and an adhesive layer. The adhesive film of the present invention may have other appropriate layers other than the base material layer and the adhesive agent layer within the range that does not impair the effect of the present invention.

The base material layer may be one layer, or may be two or more layers. The base material layer is preferably one layer at the point that the effects of the present invention can be further exhibited.

The adhesive layer may be one layer, or may be two or more layers. The adhesive agent layer is preferably one layer at the point that the effects of the present invention can be further exhibited.

The adhesive film according to the embodiment of the present invention may also be provided with any suitable release liner on the surface of the adhesive layer opposite to the substrate layer for protection before use.

As the release liner, for example, a release liner in which the surface of a base material such as paper or a plastic film (liner base material) is treated with silicone, a surface of a base material such as a paper or plastic film (liner base material) Release liner laminated with polyolefin resin, etc. Regarding the plastic film used as the base material of the gasket, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, etc.

The thickness of the release liner is preferably from 1 μm to 500 μm, more preferably from 3 μm to 450 μm, further preferably from 5 μm to 400 μm, especially preferably from 10 μm to 300 μm.

The thickness of the adhesive film according to the embodiment of the present invention is preferably 1 μm to 500 μm, more preferably 5 μm to 200 μm, further preferably 10 μm to 150 μm, especially preferably 20 μm to 100 μm, most preferably 30μm～80μm. If the thickness of the adhesive film of embodiment of this invention exists in the said range, the effect of this invention can be exhibited further.

The total light transmittance of the adhesive film according to the embodiment of the present invention is preferably at least 20%, more preferably at least 30%, further preferably at least 40%, especially preferably at least 50%, most preferably at least 60%. If the total light transmittance of the adhesive film of this invention is in the said range, it can exhibit further excellent transparency.

The haze of the adhesive film according to the embodiment of the present invention is preferably 15% or less, more preferably 13% or less, further preferably 10% or less, especially preferably 8% or less, most preferably 6% or less. If the haze of the adhesive film of this invention exists in the said range, it can exhibit further excellent transparency.

The adhesive film according to the embodiment of the present invention can have both excellent adhesiveness and excellent elasticity, so it is preferably used in flexible devices such as foldable devices or rollable devices.

"Substrate layer" The thickness of the substrate layer is preferably from 1 μm to 500 μm, more preferably from 5 μm to 300 μm, further preferably from 10 μm to 100 μm, especially preferably from 15 μm to 80 μm, most preferably from 20 μm to 60 μm . If the thickness of the base material layer is within the above range, the effects of the present invention can be further exhibited.

The Young's modulus of the substrate layer at 23°C is preferably at least 6.0×10 ⁷ Pa, more preferably at least 1.0×10 ⁸ Pa, further preferably at least 5.0×10 ⁸ Pa, and most preferably at least 8.0×10 ⁸ Pa Above, more preferably 1.0×10 ⁹ Pa or above. Typically, the upper limit of the Young's modulus of the substrate layer at 23°C is preferably not more than 1.0×10 ¹¹ Pa. If the Young's modulus of the base material layer at 23° C. is within the above-mentioned range, the effect of the present invention can be further exhibited. If the Young’s modulus of the substrate layer at 23°C is too low, when the adhesive film is bent and has an angle, it may not be able to maintain the stretch of the outer diameter side enough to resist the compression of the inner diameter side, and the thickness is likely to change. It is easy to bulge from the adherend. If the Young's modulus of the substrate layer at 23° C. is too high, the adhesive film may not be easily deformed. The determination method of Young's modulus will be described below.

As for the material of the base material layer, any appropriate material can be adopted within the range not impairing the effect of the present invention. As a material of such a base material layer, a typical resin material is mentioned.

Regarding the resin material used as the material of the substrate layer, for example, polyimide (PI), polyether ether ketone (PEEK), polyethylene terephthalate (PET), polyethylene naphthalate Acrylic resins such as ester (PEN), polybutylene terephthalate (PBT), polymethyl methacrylate (PMMA), polycarbonate, triacetyl cellulose (TAC), polystyrene, polyarylate , polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), fully aromatic polyamide (aromatic polyamide) , polyvinyl chloride (PVC), polyvinyl acetate, polyphenylene sulfide (PPS), fluorine-based resins, and cyclic olefin-based polymers.

"Adhesive Layer" As for the thickness of the adhesive layer, the thickness of the acrylic adhesive sheet according to the embodiment of the present invention can be used. Therefore, the thickness of the adhesive layer is preferably 25 μm or less, more preferably 23 μm or less, further preferably 20 μm or less, further preferably 18 μm or less, especially preferably 15 μm or less, most preferably 13 μm or less . The thinner the above-mentioned thickness, the better, but in consideration of the balance with other adhesive properties, etc., the lower limit of the above-mentioned thickness is preferably 1 μm or more, more preferably 3 μm or more, and more preferably 5 μm or more, especially preferably 5 μm or more. More than 7 μm, preferably more than 9 μm.

The adhesive layer is one form of an acrylic adhesive sheet. As the formation method of the adhesive layer, any suitable formation method can be employ|adopted in the range which does not impair the effect of this invention. As such a forming method, for example, the method of applying an acrylic adhesive composition on an arbitrary suitable substrate, heating, drying, and curing as necessary to form an acrylic adhesive composition on the substrate An acrylic adhesive layer is formed. Regarding the mechanism of such coating, any appropriate mechanism can be adopted within the range not impairing the effect of the present invention. As such a coating mechanism, for example, a gravure roll coater, a reverse roll coater, a touch roll coater, a dip roll coater, a rod coater, a knife coater, an air knife Coater, Spray Coater, Notch Wheel Coater, Direct Coater, Roller Brush Coater. Heating and drying of the acrylic pressure-sensitive adhesive composition can adopt any appropriate method within the range that does not impair the effect of the present invention. As such a method of heating and drying, heating to about 60°C to 180°C may, for example, be mentioned. Curing of the acrylic adhesive composition can employ any appropriate method within the range not impairing the effect of the present invention. Examples of such curing methods include ultraviolet irradiation, laser irradiation, alpha-ray irradiation, beta-ray irradiation, gamma-ray irradiation, X-ray irradiation, and electron beam irradiation.

"Flexible Device" The adhesive film of the present invention can have both excellent adhesiveness and excellent elasticity, so it can be preferably installed on a bendable device (bendable device) or a foldable device (foldable device) or a foldable device with a movable bending part. Flexible devices such as curling devices (rollable devices).

That is, the flexible device according to the embodiment of the present invention includes the adhesive film according to the embodiment of the present invention. The flexible device of the present invention includes the adhesive film of the embodiment of the present invention. The foldable device of the present invention may also include any other suitable components as long as it has the adhesive film of the embodiment of the present invention.

FIG. 1 is a schematic cross-sectional view showing one embodiment of the flexible device of the present invention as a representative example of a usage form of the adhesive film according to the embodiment of the present invention. In FIG. 1 , a foldable device 1000 according to an embodiment of the present invention includes a cover film 10, an adhesive layer 20, a polarizer 30, an adhesive layer 40, a touch sensor 50, an adhesive layer 60, an OLED (organic light- emitting diode (organic light emitting diode) 70, the adhesive film 100 of the embodiment of the present invention. The adhesive film 100 according to the embodiment of the present invention includes an adhesive layer 80 and a base material layer 90 in FIG. 1 . The adhesive layer 20, the adhesive layer 40, and the adhesive layer 60 may contain the same adhesive composition as the adhesive layer 80 constituting the adhesive film 100 according to the embodiment of the present invention, or may contain a different composition. The adhesive layer of the adhesive. Example

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. However, the present invention is not limited by any of these. In addition, in the following description, unless otherwise specified, "part" and "%" are based on weight.

Abbreviations and details of raw materials used in the following production examples, examples, and comparative examples are as follows. 2EHA: 2-ethylhexyl acrylate (glass transition temperature Tg of its homopolymer (homopolymer) = -70°C) LA: lauryl acrylate (glass transition temperature of its homopolymer (homopolymer) Tg = -23°C) BA: n-butyl acrylate (glass transition temperature Tg of its homopolymer (homopolymer) = -55°C) 4HBA: 4-hydroxybutyl acrylate (glass transition temperature of its homopolymer (homopolymer) Tg = -32°C) NVP: N-vinyl-2-pyrrolidone (glass transition temperature Tg of its homopolymer (homopolymer) = about 80° C.) AOMA (registered trademark): Cyclopolymerizable monomer manufactured by Nippon Shokubai Co., Ltd. In formula (1), R ¹ is a methyl group, R ² is a hydrogen atom) (the glass transition temperature Tg of its homopolymer (homopolymer) = about 80°C) V#216: Acrylic acid-2-butylaminoformyloxy Ethyl ester (Viscoat#216, manufactured by Osaka Organic Chemical Industry Co., Ltd.) (in the general formula (2), R ³ is -CH ₂ CH ₂ -, R ⁴ is n-butyl, R ⁵ is a hydrogen atom) (the homopolymer Homopolymer glass transition temperature Tg = 0°C) MMA: methyl methacrylate HEA: hydroxyethyl acrylate AIBN: 2,2'-azobisisobutyronitrile Irgacure184: photopolymerization initiator (manufactured by BASF Corporation ) Irgacure651: photopolymerization initiator (manufactured by BASF) DCPMA: dicyclopentyl methacrylate CHMA: cyclohexyl methacrylate AA: acrylic acid C/HX: Coronate HX (isocyanate-based cross-linking agent manufactured by Toso Corporation) ) D110N: Takenate D110N (Isocyanate-based cross-linking agent manufactured by Mitsui Chemicals Co., Ltd.) HDDA: 1,6-hexanediol diacrylate BPO: peroxide (Nyper BMT-40SV, manufactured by NOF Corporation) Iron triacetylacetonate : Iron catalyst (manufactured by Nippon Chemical Industry Co., Ltd.) Irganox1010: Antioxidant (manufactured by BASF Corporation) KBM403: Silane coupling agent (manufactured by Shin-Etsu Chemical Industry Co., Ltd.)

＜Adhesion to polyimide film＞ After peeling off the separator (MRQ50T100J) with the weakest peeling force among the separators of the adhesive film, a polyimide base material (trade name "Upilex 25RN", manufactured by Ube Industries, Ltd.) with a thickness of 25 μm was attached, and the attached Adhesive film for polyimide substrate. Cut the adhesive film of the agglomerated polyimide base material into a width of 25 mm x a length of 100 mm, peel off the separator (JT-50Wa) to expose the adhesive, and stick it to the polyimide with a 2 kg hand pressure roller back and forth once. An imide film (trade name "Upilex 50S", manufactured by Ube Industries, Ltd.) was used to obtain a sample for evaluation. The obtained evaluation sample was stored at room temperature for 30 minutes, and then measured with a tensile tester. As a tensile testing machine, a product named "Autograph AG-Xplus HS 6000 mm/min high-speed mode (AG-50NX plus)" manufactured by Shimadzu Corporation was used. After the sample for evaluation was placed in the tensile testing machine, the tensile test was started. The conditions of the tensile test were set at a peeling angle of 180 degrees and a peeling speed (tensile speed) of 300 mm/min. The load when peeling off the adhesive film from the said polyimide film (Upilex 50S) was measured, and the average load at this time was made into adhesive force.

＜Adhesion to glass＞ Cut the adhesive film of the agglomerated polyimide substrate into a width of 25 mm×length of 100 mm, peel off the spacer (JT-50Wa) to expose the adhesive, and attach it to the glass with a 2 kg hand pressure roller back and forth once (product name: S2004U8, manufactured by Matsunami Glass Industry Co., Ltd.), instead of the non-tin surface, cut the adhesive film of the agglomerated polyimide substrate into a width of 25 mm x length of 100 mm, and peel off the separator (JT-50Wa) to make the adhesion The agent was exposed, and it was attached to a polyimide film (trade name "Upilex 50S", manufactured by Ube Industries, Ltd.) by a 2 kg hand roller back and forth once. The method of measuring the adhesive force> is carried out in the same way.

＜Storage modulus G'＞ The storage modulus G' is equivalent to the part stored in the form of elastic energy when the material is deformed, and it is an index indicating the degree of hardness. Only the adhesive layer was removed from the adhesive film, laminated to a thickness of about 1 mm, and punched into ϕ9 mm to make cylindrical pellets as samples for measurement. Using a dynamic viscoelasticity measurement device (ARES manufactured by Rheometrics), the obtained measurement sample was fixed to a ϕ8 mm parallel plate jig, and the storage modulus G' was calculated. The measurement conditions are as follows. Assay: Shear Mode Temperature range: -60℃～210℃ Heating rate: 5°C/min Frequency: 1Hz

＜Weight average molecular weight Mw＞ The weight average molecular weight is determined by gel permeation chromatography (GPC) method. Specifically, using "Agilent 1260 Infinity" (manufactured by Agilent Technologies) as a GPC measurement device, a 0.1% by weight tetrahydrofuran solution containing an amine component was prepared in consideration of the polymer concentration of the sample, and left for 20 hours. After filtration with a 0.45 μm membrane filter, the filtrate was subjected to GPC determination. Measurement was performed under the following conditions, and it calculated from the standard polystyrene conversion value. (Molecular weight measurement conditions) ・Sample concentration: 0.1% by weight (tetrahydrofuran solution containing amine components) ・Sample injection volume: 100 μL ・Tube string: Trade name "TSKgel GMH-H(S)" (manufactured by Toso Corporation) ・Eluent: Tetrahydrofuran with added amine components ・Flow rate: 0.5 mL/min ・Detector: Differential refractometer (RI) ・Column temperature (measuring temperature): 40°C ・Standard sample: polystyrene (PS)

[Production example 1]: Production of acrylic polymer (1) 68.0 parts by weight of 2EHA, 19.4 parts by weight of LA, 7.8 parts by weight of BA, 3.9 parts by weight of 4HBA, and 1.0 parts by weight of AOMA (registered trademark) were put into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler. Add 0.1 part by weight of AIBN as a polymerization initiator, add ethyl acetate so that the total concentration thereof becomes 42% by weight, stir slowly, and replace the system with nitrogen for 1 hour to keep the liquid temperature in the flask at 58 The polymerization reaction was carried out at about °C for 5 hours, and after the completion of the reaction, ethyl acetate was added to adjust the polymer concentration to 32% by weight to obtain a solution of the acrylic polymer (1). The results are shown in Table 1.

[Production examples 2-6, 8]: Production of acrylic polymers (2)-(6), (8) Except having changed monomer components and various conditions as described in Table 1, it carried out similarly to manufacture example 1, and obtained the solution of acrylic-type polymer (2)-(6), (8). The results are shown in Table 1.

[Manufacturing Example 7]: Preparation of Acrylic Polymer (7) An acrylic resin (manufactured by Soken Chemical Co., Ltd., trade name "SK2137") obtained by using 99.0 parts by weight of BA and 1.0 part by weight of 4HBA as monomer components was used as an acrylic polymer (7). The results are shown in Table 1.

[Manufacture Example 9]: Manufacture of acrylic oligomer (A) Mix 60 parts by weight of DCPMA and 40 parts by weight of MMA as monomer components, 3.5 parts by weight of α-thioglycerol as a chain transfer agent, and 100 parts by weight of toluene as a polymerization solvent, and stir at 70°C under a nitrogen atmosphere 1 hour. Next, after putting in 0.2 weight part of AIBN as a thermal-polymerization initiator, and reacting at 70 degreeC for 2 hours, it heated up to 80 degreeC and reacted for 2 hours, and obtained the acrylic oligomer (A). The weight average molecular weight Mw of the acrylic oligomer (A) was 5100, and the glass transition temperature (Tg) was 130 degreeC.

[Manufacture Example 10]: Manufacture of acrylic oligomer (B) 95 parts by weight of CHMA and 5 parts by weight of AA as monomer components, 10 parts by weight of α-methylstyrene dimer (manufactured by NOF Corporation, trade name "Nofmer MSD") as a chain transfer agent, 10 parts by weight of AIBN as a starter was mixed with toluene so that the concentration of these raw materials became 50% by weight, and reacted at 85° C. for 2 hours under a nitrogen atmosphere. Next, the temperature was raised to 86° C., and the reaction was performed for 1.5 hours to obtain an acrylic oligomer (B). The weight average molecular weight of the acrylic oligomer (B) was 4000, and the glass transition temperature (Tg) was 67 degreeC.

[Example 1] 100 parts by weight of acrylic polymer (1), 0.09 parts by weight of C/HX as a crosslinking agent, 2 parts by weight of acrylic oligomer (A), 0.3 parts by weight of Irganox1010 as an antioxidant, and the third part of a catalyst Mix 0.01 parts by weight of iron acetylacetonate, stir well, and dilute with ethyl acetate and 2% by weight of acetylacetone as a solvent amount so that the total solid content becomes 21% by weight, thereby obtaining an acrylic adhesive composition (1) Coating solution. The obtained coating solution of the acrylic adhesive composition (1) was coated on a 50 μm-thick release sheet containing a polyester resin ( Product name: JT-50Wa, manufactured by Nitto Denko Co., Ltd.), the silicone-treated surface was dried at a drying temperature of 130°C and a drying time of 1 minute. Then, the silicone-treated side of a 50 μm-thick release sheet made of polyester resin (product name: MRQ50T100J, manufactured by Mitsubishi Chemical Co., Ltd.) that has been silicone-treated on one side is in contact with the surface of the obtained adhesive layer. bonded to obtain an adhesive film (1). This was aged at 50° C. for 3 days, and various evaluations were performed. The results are shown in Table 3.

[Embodiments 2-9] Except for changing the raw material composition and various conditions as shown in Table 2, it was carried out in the same manner as in Example 1 to obtain coating solutions of acrylic adhesive compositions (2) to (9) and adhesive films (2) to (9). . This was aged at 50° C. for 3 days, and various evaluations were performed. The results are shown in Table 3.

[Comparative examples 1 to 5] Except for changing the raw material composition and various conditions as shown in Table 2, it was carried out in the same manner as in Example 1 to obtain coating solutions of acrylic adhesive compositions (C1) to (C5) and adhesive films (C1) to (C5). . This was aged at 50° C. for 3 days, and various evaluations were performed. The results are shown in Table 3.

[Table 1] Acrylic polymer Monomer composition (parts by weight) Polymerization initiator (parts by weight) Polymerization concentration (weight%) Polymerization time (hours) Polymerization temperature (℃) Polymer concentration after reaction (weight %) Mw (ten thousand) 2EHA LA BA 4HBA NVP AOMA V#216 AIBN (1) 68.0 19.4 7.8 3.9 - 1.0 - 0.1 42 5 58 32 135 (2) 66.7 19.0 7.6 3.8 - 1.0 1.9 0.1 42 5 58 32 141 (3) 67.9 19.4 7.8 3.9 1.0 - - 0.1 42 5 58 32 157 (4) 70.3 8.0 20.1 1.0 0.6 - - 0.1 47 6 56 twenty four 209 (5) 50.4 39.0 - 8.9 - 2.4 - 0.2 40 7 60 36 116 (6) 89.4 - - 8.9 1.7 - - 0.2 40 7 60 36 90 (7) - - 99.0 1.0 - - - - - - - 16.5 160 (8) 68.6 7.8 19.6 3.9 - - - 0.1 42 5 58 27 160

[Table 2] 100 parts by weight of acrylic polymer Crosslinking agent (parts by weight) Acrylic oligomer (parts by weight) Antioxidant (parts by weight) Catalyst (parts by weight) Acetyl acetone Thickness (μm) drying conditions BPO C/HX D110N (A) (B) Irganox1010 Iron triacetylacetonate temperature(℃) time (minutes) Example 1 (1) - 0.09 2 - 0.3 0.01 2% by weight of solvent 13 130 1 Example 2 (2) - 0.05 - 2 - 0.3 0.01 2% by weight of solvent 13 130 1 Example 3 (3) - 0.05 - 2 - 0.3 0.01 2% by weight of solvent 13 130 1 Example 4 (4) - 0.03 - 3 - 0.3 0.01 2% by weight of solvent 13 130 1 Example 5 (5) - 0.10 - 3 - 0.3 0.01 2% by weight of solvent 13 130 1 Example 6 (4) - 0.03 - 5 0.3 0.01 2% by weight of solvent 13 130 1 Example 7 (4) - 0.03 - - 5 0.3 0.01 2% by weight of solvent 13 130 1 Example 8 (4) 0.25 - - 3 - 0.3 0.01 2% by weight of solvent 13 155 2 Example 9 (4) 0.28 - - 3 - 0.3 - - 13 155 2 Comparative example 1 (6) - 0.10 - 0 0 0.3 0.01 2% by weight of solvent 18 130 1 Comparative example 2 (7) 0.3 - 0.095 0 0 - - - 13 155 2 Comparative example 3 (7) 0.3 - 0.095 7 - - - - 13 155 2 Comparative example 4 (8) - 0.10 - 5 - 0.3 0.01 2% by weight of solvent 13 130 1 Comparative Example 5 (7) 0.3 - 0.095 - 10 - - - 20 155 2

[table 3] Paste thickness (μm) Adhesion (N/25 mm) Storage modulus G' (kPa) at -20°C p-polyimide membrane against glass Example 1 13 8.4 8.0 115 Example 2 13 8.0 8.3 114 Example 3 13 8.0 8.1 92 Example 4 13 7.2 7.1 127 Example 5 13 7.0 7.7 140 Example 6 13 7.5 6.9 148 Example 7 13 7.4 7.2 181 Example 8 13 7.2 7.5 155 Example 9 13 7.0 7.2 140 Comparative example 1 18 6.4 1.9 142 Comparative example 2 13 5.0 2.8 200 Comparative example 3 13 7.3 6.9 415 Comparative example 4 13 4.6 3.8 123 Comparative Example 5 20 7.2 8.4 352 [Industrial availability]

The acrylic adhesive sheet or the like according to the embodiment of the present invention can be used in so-called flexible devices such as foldable devices or rollable devices.

10: Cover film 20: Adhesive layer 30: polarizer 40: Adhesive layer 50:Touch sensor 60: Adhesive layer 70: OLED 80: Adhesive layer 90: substrate layer 100: adhesive film 1000: collapsible device

Fig. 1 is a schematic cross-sectional view showing one embodiment of the flexible device of the present invention, showing one usage form of the adhesive film according to the embodiment of the present invention.

10: Cover film

20: Adhesive layer

30: polarizer

40: Adhesive layer

50:Touch sensor

60: Adhesive layer

70: OLED

80: Adhesive layer

90: substrate layer

100: adhesive film

1000: collapsible device

Claims (14)

An acrylic adhesive sheet whose adhesion to polyimide film is above 5.5 N/25 mm, and its adhesion to glass is 5.5 N at 23°C, peeling speed 300 mm/min, and peeling angle 180 degrees /25 mm or more, and The storage modulus G' at -20°C is below 200 kPa, The thickness is 25 μm or less. An acrylic adhesive composition, which forms the acrylic adhesive sheet as claimed in claim 1, It contains an acrylic polymer (P) and an oligomer. The acrylic adhesive composition according to claim 2, wherein the above-mentioned acrylic polymer (P) is obtained by polymerizing the monomer component (M), and the monomer component (M) contains monomers having polar groups other than hydroxyl groups. body (m5). The acrylic adhesive composition according to claim 3, wherein the monomer component (M) has a content ratio of the monomer (m5) having a polar group other than the hydroxyl group in the range of 0.1% to 5.0% by weight. The acrylic adhesive composition as claimed in item 3 or 4, wherein the above-mentioned monomer (m5) having a polar group other than hydroxyl group comprises monomer (1) represented by general formula (1), general formula (2 ) represented by monomer (2) and at least one of the group consisting of N-vinyl-2-pyrrolidone, [Chem. 1]

(In general formula (1), R ¹ is an alkyl group with 1 to 10 carbons, R ² is a hydrogen atom, an alkyl group with 1 to 10 carbons or -COOR group, R is an alkyl group with 1 to 10 carbons) [Chem 2]

(In general formula (2), R ³ is an alkylene group having 1 to 10 carbons, R ⁴ is an alkyl group having 1 to 10 carbons, and R ⁵ is a hydrogen atom or a methyl group). The acrylic adhesive composition according to any one of claims 2 to 5, wherein the content ratio of the oligomer in the acrylic adhesive composition is 100 parts by weight of the acrylic polymer (P) 0.1 to 6.5 parts by weight. The acrylic adhesive composition according to any one of claims 2 to 6, wherein the weight average molecular weight Mw of the oligomer is 1,000-30,000. The acrylic adhesive composition according to any one of claims 3 to 7, wherein the above-mentioned monomer component (M) contains an alkyl (meth)acrylate. The acrylic adhesive composition according to claim 8, wherein the glass transition temperature Tg of the homopolymer of the above-mentioned alkyl (meth)acrylate is -10°C or lower. The acrylic adhesive composition according to claim 8 or 9, wherein the content ratio of the above-mentioned alkyl (meth)acrylate in the above-mentioned monomer component (M) is 50% by weight to 99% by weight. The acrylic adhesive composition according to any one of claims 3 to 10, wherein the monomer component (M) includes a hydroxyl-containing monomer (m4). The acrylic adhesive composition according to Claim 11, wherein the content ratio of the above-mentioned hydroxyl-containing monomer (m4) in the above-mentioned monomer component (M) is 0.01% by weight to 30% by weight. An adhesive film having an adhesive layer comprising the acrylic adhesive sheet according to claim 1. A flexible device, which is provided with the adhesive film according to claim 13.

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