KR102008183B1 - Adhesive composition, adhesive film and image display device - Google Patents

Abstract

[Problem] The present invention provides a pressure-sensitive adhesive composition capable of suppressing the occurrence of abnormal smell or outgas without peeling or lifting even if the bending operation is performed under two conditions of high temperature and low temperature.
[Solution] A main component (A) consisting of a curable compound and a photopolymerization initiator (B), wherein the main component (A) contains a (meth) acrylic acid ester monomer (a-1) and a hydroxyl group-containing (meth) acryl monomer. Structural unit derived from the mixture of (a-2) or structural unit (1) derived from said (a-1), said (a-2), and (a-1), and (a-2) ( A mixture of copolymer (a-3) containing 2), wherein the photopolymerization initiator (B) is oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) Propane) and 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propane-1-one The adhesive composition whose glass transition temperature after hardening is less than -57.0 degreeC.

Description

Adhesive composition, adhesive film and image display device {ADHESIVE COMPOSITION, ADHESIVE FILM AND IMAGE DISPLAY DEVICE}

The present invention relates to an adhesive composition suitable for use in a flexible device, an adhesive film formed by curing the adhesive composition, and an image display apparatus including the same. In detail, this invention is equipped with the adhesive composition for optical films, the adhesive film for optical films formed by hardening this adhesive composition, the adhesive sheet for displays (adhesive optical film) provided with this adhesive film, and this adhesive film The present invention relates to an image display device, and to a pressure-sensitive adhesive composition in which peeling or lifting does not occur even if a laminate obtained is subjected to a bending operation of deforming an optical film bonded under each durability test condition. The pressure-sensitive adhesive composition of the present invention is suitably used for lamination of a thin film adherend including an optical film or sheet, and also used for various films or sheets used in liquid crystal display devices such as flexible displays, electroluminescence devices, and the like. It is used suitably for manufacture, and can be commercially available in these technical fields.

Currently, flat panel display panels such as liquid crystal display panels (LCDs) and plasma display panels (PDPs) are mainly used as display panels. The laminated body in which the several film was laminated | stacked is bonded to the surface of a flat panel display panel normally. For example, in LCD, optical films, such as a polarizing plate, a phase difference plate, a viewing angle expansion film, and a brightness improvement film, are laminated | stacked on the surface of a liquid crystal panel normally. And each layer which comprises a flat panel display panel is normally bonded by the adhesive film formed of various adhesives.

On the other hand, in recent years, in addition to flat panel displays, development of a flexible display including a curved display has been progressed from the viewpoints of designability, variety of usage methods, and the like, and flexibility for display panels has been required. BACKGROUND OF THE INVENTION An organic light emitting diode panel (OLED) is mainly used for flexible displays such as curved displays.

The optical film used for flexible displays, such as this curved display, and the optical film laminated body laminated | stacked by the adhesive film or the adhesive layer, in addition to the optical characteristic and durability required by the conventional flat panel display panel, Even if the bending operation to be deformed is required, no peeling or lifting occurs.

As an adhesive film used for the conventional optical film laminated body for flat panel display panels, Patent document 1 proposes the adhesive sheet which bridge | crosslinks the adhesive composition containing an acrylic ester polymer, an acrylic crosslinking monomer, and a crosslinking initiator. have. PTL 2 proposes a photopolymerizable pressure-sensitive adhesive composition containing an acrylic syrup containing an alkoxyalkyl (meth) acrylate monomer, a monomer having two or more polymerizable unsaturated groups, a crosslinking agent and a photopolymerization initiator. In patent document 3, the adhesive composition for optical members containing a base polymer and lactone modified tris [(meth) acryloxyalkyl] isocyanurate is proposed. In patent document 4, the resin composition for optics containing an acrylic acid derivative, an acrylic acid derivative polymer, and a crosslinking agent is proposed.

Prior art literature

(Patent Document 1) JP2014-025073 A

(Patent Document 2) JP2007-161909 A

(Patent Document 3) JP2011-225704 A

(Patent Document 4) JP2010-1449 A

Flexible displays, such as organic light emitting diode panels (OLEDs), are expected to be used under a variety of environments, requiring durability in a wide range of temperatures, or folding resistance (bending resistance) under both high and low temperatures. do. However, in the adhesive of patent document 1, when the adhesive is used for the adhesive film of a flexible display because of the crosslinked structure by an acryl-type crosslinking monomer, at the high temperature during the folding test in two conditions of durability, high temperature, and low temperature. Peeling occurs in the bending operation. Even in the adhesive described in patent document 2, peeling test on two conditions of high temperature and low temperature is not satisfy | filled, and peeling and lifting generate | occur | produce. Moreover, when the polymerization initiator of patent documents 1 and 2 is used, the problem of outgas generation and a bad smell arises. Also in the adhesives described in Patent Documents 3 and 4, there is a problem that the folding test under both conditions of high temperature and low temperature is not satisfied, peeling and lifting occurs, and durability during bending is also not satisfied.

Therefore, this invention is made | formed in view of the said situation, Even if it bends under two conditions of high temperature and low temperature, peeling or lifting does not generate | occur | produce, and it provides the adhesive composition which can suppress generation | occurrence | production of a strange smell or outgas. It aims to do it.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to solve the said problem, the present inventors included the main component (A) which consists of a curable compound containing a predetermined | prescribed acrylic compound, and the predetermined photoinitiator (B), and after hardening It found that the said subject is solved by the adhesive composition whose glass transition temperature is less than -57.0 degreeC, and came to completion of this invention.

According to the present invention, under various durability test conditions, even if bending operation is performed under two conditions of high temperature and low temperature with respect to the bonded film, peeling or lifting does not occur, and folding resistance is excellent under both high temperature and low temperature conditions. Moreover, the adhesive composition which can suppress generation | occurrence | production of an abnormal smell and outgas can be provided. The pressure-sensitive adhesive composition according to the present invention is particularly suitable for flexible display applications.

1 is a cross-sectional view and a plan view of a specimen for measuring shear deformation.
2 is a graph for calculation of shear deformation.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described. In addition, this invention is not limited only to the following embodiment.

Unless otherwise specified in the present specification, the measurement of the operation and the physical properties is measured under the conditions of room temperature (20 ° C or more and 25 ° C or less) / relative humidity 40% RH or more and 50% RH or less.

[Adhesive Composition]

One aspect of the present invention includes a main component (A) and a photopolymerization initiator (B) made of a curable compound, wherein the main component (A) comprises (i) a (meth) acrylic acid ester monomer (a-1) and a hydroxyl group. A mixture of the containing (meth) acrylic monomer (a-2), or (ii) the (meth) acrylic acid ester monomer (a-1), the hydroxyl group-containing (meth) acrylic monomer (a-2), and the ( The copolymer (a-) containing the structural unit (1) derived from the meta) acrylic acid ester monomer (a-1), and the structural unit (2) derived from the said hydroxyl group containing (meth) acryl monomer (a-2). 3) a mixture of 3), wherein the photopolymerization initiator (B) is oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) and 2-hydroxy-1 At least one of-{4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propane-1-one, and the glass transition temperature after curing is -57.0 ° C. Less than, pressure-sensitive adhesive composition The. According to the present invention, under various durability test conditions, even if bending operation is performed under two conditions of high temperature and low temperature with respect to the bonded film, peeling or lifting does not occur, and folding resistance is excellent under both high temperature and low temperature conditions. And it can provide the adhesive composition which can suppress generation | occurrence | production of a strange strange smell and outgas.

For some reason, the detail of whether the said effect is acquired by the adhesive composition of this invention is unclear, but it thinks as follows. That is, if the glass transition temperature after curing of the pressure-sensitive adhesive composition is too high (-57.0 ° C. or more), sufficient flexibility is not obtained for the cured product of the pressure-sensitive adhesive composition at low temperature (eg, −20 ° C.), and folding at low temperature is achieved. It is difficult to obtain resistance (see Comparative Example 3). On the other hand, the present inventors used the (meth) acrylic acid ester monomer (a-1) (or the copolymer (a-3) containing the structural unit derived from this) with low glass transition temperature of a homopolymer. By using the curable compound to be included as the main component (A) and adjusting and controlling the glass transition temperature after curing of the pressure-sensitive adhesive composition to less than -57.0 ° C, a high temperature (for example, 80 ° C) and a low temperature (for example, -20 It was found that the folding resistance at both degrees C) was improved.

In addition, although the detailed reason is not clear, the main component (A) which consists of a curable compound containing a predetermined | prescribed acryl-type compound is combined with the predetermined photoinitiator (B), and the glass transition temperature after hardening of an adhesive composition is made low like the said range. The present inventors have found that the folding resistance can be improved, and the weight loss rate of the pressure-sensitive adhesive composition under high temperature can be made small, which can effectively suppress the occurrence of an odd smell or outgas. This is because when the molecular structure of the photopolymerization initiator is made of Irgacure 184 (see Comparative Example 1) having a lower molecular weight than the photopolymerization initiator (B) or the like, the predetermined glass transition temperature after curing of the pressure-sensitive adhesive composition can be lowered as in the above range. By combining the main component (A) made of a curable compound containing an acryl-based compound, the folding resistance at high and low temperatures can be improved, but the remaining photopolymerization initiator has been gasified, resulting in a strange odor or an outgas. . Moreover, when the molecular structure of a photoinitiator uses the ESAcure KIP160 (refer comparative example 2) etc. which have a molecular structure (similarly high molecular weight) similar to a photoinitiator (B), Although generation | occurrence | production can be suppressed, the problem that the folding resistance in high temperature (for example, 80 degreeC) is not fully acquired due to the molecular structure has arisen. In the adhesive composition of this invention, the glass transition temperature after hardening of an adhesive composition is made to combine the main component (A) which consists of curable compounds containing the predetermined | prescribed acrylic compound which can be made low like the said range, with predetermined | prescribed photoinitiator (B). It is thought that the molecular structure which a predetermined photoinitiator (B) has can suppress the generation | occurrence | production of a strange odor and outgas, and can also improve the folding resistance at high temperature and low temperature. Moreover, it is thought that the storage elastic modulus at high temperature (for example, 80 degreeC) can be improved because of the molecular structure of a photoinitiator.

Moreover, in the adhesive composition of this invention, a curable compound containing a high polar hydroxyl group containing (meth) acryl monomer (a-2) (or a copolymer (a-3) containing the structural unit derived from this) is a main component. It is a requirement to use it as. By using such a structure, it is thought that adhesive force and durability can be ensured by the high polarity of a hydroxyl group containing (meth) acryl monomer (a-2). Moreover, if it is a hydroxyl group containing (meth) acryl monomer (a-2) (or the copolymer (a-3) containing the structural unit derived from this), folding resistance can be improved and it is the case of the adhesive composition under high temperature. It is considered that the weight reduction rate can be made small, and the occurrence of strange smells and outgases can be effectively suppressed.

In addition, the said mechanism is speculative, and this invention is not limited to the said mechanism at all.

Although the glass transition temperature (Tg) after hardening of the adhesive composition of this invention should just be less than -57.0 degreeC, it is preferable that it is -57.5 degrees C or less and -59.0 degrees C or less from a viewpoint of folding resistance at low temperature. The lower limit of the glass transition temperature (Tg) after curing of the pressure-sensitive adhesive composition is not particularly limited, and is included in the technical scope of the present invention when the effect of the present invention can be effectively expressed. In addition, the glass transition temperature after hardening of an adhesive composition can be calculated | required by the method as described in an Example. In order to make the glass transition temperature after hardening of an adhesive composition into the said range, in consideration of the glass transition temperature of a homopolymer, what is necessary is just to select suitably the monomer used for preparation of a main component (A). Or (meth) acrylic acid ester monomer (a-1) having a low glass transition temperature of the homopolymer and a monomer having a relatively high glass transition temperature of the homopolymer (for example, a hydroxyl group-containing (meth) acrylic monomer (a-2) B, the composition ratio of the monomer (a ') copolymerizable with the component (a-1) and the component (a-2) may be appropriately adjusted. Preferably, the minimum of glass transition temperature (Tg) after hardening of the adhesive composition of this invention is -70 degreeC, More preferably, it is -65 degreeC. In the above range, even when the pressure-sensitive operation of the pressure-sensitive adhesive film at a low temperature and high temperature does not cause peeling or lifting, the folding resistance under both high and low temperature conditions is excellent.

As for the adhesive composition of this invention, from the viewpoint of the bending resistance at high temperature, the storage elastic modulus G '(80) at 80 degreeC of the adhesive composition after hardening is preferably 2.0x10 <^4> Pa or more. In addition, the upper limit of the storage elastic modulus G'80 is not restrict | limited in particular, When the effect of this invention can be expressed effectively, it is contained in the technical scope of this invention. Preferably, the upper limit of the storage elastic modulus G '(80) at 80 degreeC of the adhesive composition after hardening is 4.5 * 10 <^4> Pa, More preferably, it is 4.0 * 10 <^4> Pa, 3.5 * 10 <^4> Pa, 3.0 * 10 <^4>. . Within this range, flexural resistance at high temperatures may be good.

As for the adhesive composition of this invention, from the viewpoint of the bending resistance at low temperature, the storage elastic modulus G '(-20) at -20 degreeC of the adhesive composition after hardening is preferably 3.5x10 <^5> Pa or less, and it is 2.6x10 <^5>. It is more preferable that it is less than or equal to 2.55 * 10 <^5> Pa and less than 2.5 * 10 <^5> Pa. In addition, the minimum of storage elastic modulus G '(-20) is not specifically limited, When the effect of this invention can be expressed effectively, it is contained in the technical scope of this invention. Preferably, the minimum of storage elastic modulus G '(-20) at -20 degreeC of the adhesive composition after hardening is 0.5 * 10 <^5> Pa, More preferably, it is 0.7 * 10 <^5> Pa. Within this range, flexural resistance at low temperatures may be good.

In addition, the storage elastic modulus G'80 and G '(-20) employ | adopt the value measured by the method as described in an Example. The storage modulus G'80 and G '(-20) can be controlled by the composition etc. of the main component (A).

In the pressure-sensitive adhesive composition of the present invention, the shear deformation under 90 kPa shear stress after curing is preferably 700% or more from the viewpoint of preventing cracking of the display element and peeling of the adhesive layer when the display is bent, and is 740% or more and 800. It is more preferable that it is% or more, 850% or more, 900% or more, and it is still more preferable that it is 1000% or more. If it is the said range, bending resistance is excellent. In addition, the said shear deformation employ | adopts the value measured by the method as described in an Example. The shear deformation may include the composition of the main component (A), the composition of the copolymer (a-3) that may be included in the main component (A), the amount of the photopolymerization initiator (B) added, and a crosslinking agent or silane coupling agent added as necessary. Can be controlled by the kind and the addition amount thereof. In addition, the upper limit of shear deformation is not specifically limited, When the effect of this invention can be expressed effectively, it is contained in the technical scope of this invention. The upper limit of shear deformation under 90 kPa shear stress after curing is 2000%, preferably 1900%, 1800%, 1700%, 1600%, 1500%, 1400%, 1300%. Within this range, cracking of the display element and peeling of the adhesive layer when the display is curved can be prevented.

It is preferable that the gel fraction of the adhesive composition of this invention is 50% or more and 95% or less, It is more preferable that they are 50% or more and 90% or less, 50% or more and 85% or less, 50% or more and 80% or less, 50% or more It is more preferable that it is below, and it is especially preferable that they are 50% or more and 70% or less. If it is such a range, a punching process and a slit processing can be performed quickly as an optical member provided with an adhesive film. The gel fraction of an adhesive composition employ | adopts the value measured by the method as described in an Example. What is necessary is just to select conditions suitably, such as adjusting the addition amount of each component to the said range, in order to set a gel fraction as mentioned above.

It is preferable that the weight loss rate after hardening of the adhesive composition of this invention is less than 1.0%, It is more preferable that it is 0.9% or less, It is further more preferable that it is 0.8% or less, It is especially preferable that it is 0.6% or less. Within such a range, it is possible to effectively suppress the occurrence of an abnormal smell or outgas when the adhesive film is exposed to a high temperature (heating) environment in the manufacturing process of a display or the like. The weight loss rate with respect to the heat of the produced adhesive film adopts the value measured by the method as described in an Example. What is necessary is just to select conditions suitably, such as adjusting the addition amount of each component to the said range, in order to set a weight loss rate as mentioned above. In addition, the minimum of a weight loss rate is not specifically limited, When the effect of this invention can be expressed effectively, it is contained in the technical scope of this invention.

In the pressure-sensitive adhesive composition of the present invention, the adhesive force of the pressure-sensitive adhesive film after curing is preferably 300 g / 25 mm or more, more preferably 350 g / 25 mm or more and 550 g / 25 mm or more, still more preferably 750 g / 25 mm or more, and 800 g / 25 mm. It is especially preferable that it is to 4000g / 25mm. If it is such a range, the outstanding adhesive force with respect to an optical film etc. can be expressed. The adhesive force of the adhesive composition (adhesive film) after hardening employ | adopts the value measured by the method as described in an Example. What is necessary is just to select conditions suitably, such as adjusting the addition amount of each component to the said range, in order to set the adhesive force of the adhesive composition (adhesive film) after hardening as mentioned above. In addition, the upper limit of adhesive force is not specifically limited, When the effect of this invention can be expressed effectively, it is contained in the technical scope of this invention.

Hereinafter, each component of the adhesive composition of this invention is demonstrated in detail.

In addition, in this specification, a "(meth) acrylic acid ester monomer" is a general term of an acrylic acid ester monomer and a methacrylic acid ester monomer. Similarly, the compound containing (meth), such as (meth) acrylic acid, is also a general term for the compound which has "meta" in a name, and the compound which does not have "meta". For this reason, "(meth) acryl" includes both acryl and methacryl. "(Meth) acrylic acid ester monomer" includes both an acrylic acid ester monomer and a methacrylic acid ester monomer. "(Meth) acrylic acid" includes both acrylic acid and methacrylic acid.

In this specification, an "adhesive composition" is also only called "adhesive agent." In addition, in this specification, a "(co) polymer" is a generic term of "polymer (homopolymer)" and "copolymer."

[Main ingredient (A)]

The main component (A) used in this invention consists of a curable compound. In this invention, as a structural component of a main component (A), (i) (meth) acrylic acid ester monomer (a-1) (henceforth only a "(a-1) component") and hydroxyl group containing (meth ) A mixture of acrylic monomer (a-2) (hereinafter also referred to simply as "(a-2) component"), or (ii) said (a-1) component, said (a-2) component, and said (a- 1) The mixture of the structural unit (1) derived from a component, and the copolymer (a-3) containing the structural unit (2) derived from the said (a-2) component is included. The main component (A) contains a copolymer (a-3) comprising the structural unit (1) derived from the component (a-1) and / or the component (a-1) having a low glass transition temperature of the homopolymer, The glass transition temperature after hardening of an adhesive composition can be made low below -57.0 degreeC. In addition, the main component (A) contains a copolymer (a-3) containing the highly polar (a-2) component and / or the structural unit (2) derived from the component (a-2), thereby providing a high polarity. Excellent adhesiveness to optical films, such as a polarizing plate, can be ensured. As a curable compound which a main component (A) contains, in addition to the above, active energy ray curable monomers, such as a (meth) acryl compound, and its (co) polymer, a (meth) acryloyl group, a vinyl group, an allyl group, a propenyl group, and a dithiocarba Polyester resin, polyether resin, polyurethane resin, epoxy resin, etc. which contain polymerizable functional groups, such as a mate group, a diazo group, a cinnamildene group, and / or a cinnamoyl group, etc. can be illustrated. Preferably, the curable compound which comprises main component (A) contains one said polymerizable functional group in a molecule | numerator.

It is preferable that the viscosity of a principal component (A) is 500 mPa * s or more and less than 5000 mPa * s at 25 degreeC from a viewpoint of the applicability | paintability and adhesiveness of an adhesive composition, 1000 mPa * s or more and 4500 mPa * s or less, 1000 mPa * s or more and 2000 mPa * s or less are more preferable. In addition, the said viscosity is a value measured by the method as described in an Example.

As a preferable aspect of the main component (A) which consists of a curable compound which concerns on this invention,

(1) Form containing component (a-1) and component (a-2)

(2) A copolymer comprising the structural unit (1) derived from the component (a-1), the component (a-2) and the component (a-1) and the component (2) derived from the component (a-2) ( and a form including a-3) (hereinafter also referred to simply as copolymer (a-3)) (the form of the curable compound consisting of monomers and polymers, a so-called form of polymer syrup).

However, (3) It shall not contain the form which consists of a copolymer (a-3) (the form which a curable compound consists only of a polymer).

It is considered that the main component (A) is included in the pressure-sensitive adhesive composition of the present invention, thereby having the significance of securing the adhesiveness and basic properties of the pressure-sensitive adhesive film obtained after curing.

Especially, it is preferable that a curable compound contains a copolymer (a-3) from a viewpoint of the ease of formation of the adhesive film which concerns on this invention, the desired effect of this invention, etc. can be exhibited more efficiently. That is, the form (2) of the so-called polymer syrup is preferable.

<(a-1) (meth) acrylic acid ester monomer>

The (meth) acrylic acid ester monomer (a-1) is not particularly limited as long as the alkyl group or the group represented by-(AO) _p -Q is introduced into the ester moiety of the (meth) acrylic acid ester. However, in said "-(AO) _p -Q", A is an alkylene group, Q is an alkyl group, and p is an integer of 1 or more and 20 or less.

The main component (A) contains a copolymer (a-3) containing the structural unit (1) derived from the (meth) acrylic acid ester monomer (a-1) and / or the (meth) acrylic acid ester monomer (a-1). And glass transition temperature after hardening can be made low. Thereby, bending resistance at low temperature can be improved, without reducing adhesiveness.

The carbon number of the alkyl group or the group represented by-(AO) _p -Q is also not particularly limited. From the viewpoint of compatibility or from the viewpoint of lowering the glass transition temperature, carbon number 1 or more and 40 or less are preferable, carbon number 2 or more and 30 or less are more preferable, carbon number 3 or more and 30 or less, further preferably carbon number 4 or more and 28 or less. desirable. The ester moiety of the (meth) acrylic acid ester may be linear, branched, or cyclic, but is preferably linear or branched from the viewpoint of lowering the glass transition temperature. Moreover, carbon number is three or more in the case of ring shape.

In the group represented by-(AO) _p -Q, A has from 1 to 4 carbon atoms (ie, methylene group, ethylene) from the viewpoint of improving the adhesiveness, improving the durability, and effectively exhibiting the desired effect of the present invention. Group, a propylene group or a butylene group), and it is more preferable that they are C2-C3 or less (namely, an ethylene group or a propylene group). At this time, preferably p is an integer of 1 or more and 20 or less, More preferably, it is an integer of 1 or more and 15 or less, More preferably, it is 2 or more and 15 or less. In addition, said Q is an alkyl group. The alkyl group may be linear or branched, and is preferably 1 or more and 12 or less, more preferably 1 or more and 10 or less, as carbon number from the viewpoint of efficiently exposing the desired effect of the present invention. Preferably it is 1 or more and 8 or less, and 1 or more and 6 or less. As an example of such an alkyl group, what was enumerated above can be illustrated.

The (meth) acrylic acid ester monomer (a-1) is typically represented by the following formula (1):

Here, in the formula (1),

R ₁ is a hydrogen atom or a methyl group, and R ₂ is a group represented by the alkyl group or-(AO) _p -Q.

Although it does not restrict | limit especially as an alkyl group in R <_2> of Formula (1), As a C1-C20 alkyl group, For example, a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl Group, tert-butyl group, isobutyl group, n-hexyl group, 2-hexyl group, 3-hexyl group, cyclohexyl group, 1-methylcyclohexyl group, n-heptyl group, 2-heptyl group, 3-hep Tyl group, isoheptyl group, tert-heptyl group, n-octyl group, isooctyl group, tert-octyl group, 2-ethylhexyl group, nonyl group, isononyl group, decyl group, dodecyl group, tridecyl group, tetrade A practical group, a pentadecyl group, a hexadecyl group, a heptadecyl group, or an octadecyl group is mentioned. In particular, a methyl group, a butyl group, 2-ethylhexyl group, n-hexyl group, nonyl group, and isononyl group are preferable from a viewpoint of ensuring adhesiveness and basic characteristics.

Therefore, as a specific example of the (meth) acrylic acid ester monomer (a-1) whose R <_2> of Formula (1) is an alkyl group, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and isopropyl (Meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, n-pentyl (meth) acrylate, isopentyl (meth) acrylate, 2 -Ethylhexyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acryl The rate, lauryl (meth) acrylate, etc. are mentioned.

The (meth) acrylic acid ester monomer (a-1) which has a group represented by-(AO) _p- Q in R <_2> of Formula (1) is necessary for making the glass transition temperature after hardening of an adhesive composition below -57.0 degreeC. Do. Preferably, p is an integer of 2 or more. The group represented by-(AO) _p -Q in R ₂ of formula (1) may be an alkoxyalkyl group. As such alkoxyalkyl group, methoxyethyl group, ethoxymethyl group, ethoxyethyl group, propoxyethyl group, butoxyethyl group, methoxypropyl group, methoxybutyl group, 2-ethylhexyloxyalkyl group are preferable.

As a specific example of the (meth) acrylic acid ester monomer (a-1) which is group in which R <_2> of Formula (1) is represented by-(AO) _p- Q, methoxyethyl (meth) acrylate and ethoxymethyl (meth) acryl Ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, methoxybutyl (meth) acrylate, ethoxydi Ethylene glycol (meth) acrylate, ethoxy triethylene glycol (meth) acrylate, methoxy triethylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, propoxydiethylene glycol (meth) Acrylate, methoxy triethylene glycol (meth) acrylate, 2-ethylhexyl diglycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, methoxy dipropylene glycol (meth) acrylate Preferable.

Among the specific examples of the (meth) acrylic acid ester monomer (a-1), the main component (A) contains, in particular, from the viewpoint of lowering the glass transition temperature and polarity after curing and ensuring excellent flexibility and adhesion. As the (meth) acrylic acid ester monomer (a-1), a glass transition temperature of the homopolymer is preferably less than -60 ° C, preferably -70 ° C or more and -61 ° C or less, and more specifically, 2-ethyl It is especially preferable that it is one or more selected from the group consisting of hexyl acrylate, 2-ethylhexyl diglycol acrylate and ethoxy-diethylene glycol acrylate, methoxypolyethylene glycol acrylate.

These (a-1) components can be used individually or in mixture of 2 or more types. Preferably, the component (a-1) is a component (a-1-1) in which R ₂ in the formula (1) is the alkyl group, and R ₂ in the formula (1) is-(AO) _p -Q. Mixtures of the component (a-1-2) represented by the group can be used. In addition, a commercial item may be used for the component (a-1) or a synthetic product may be used.

As a commercial item of (a-1) component, AEH, AME, 2EHA (above, Nihon Shokubai Co., Ltd.), light acrylate (registered trademark) EC-A, light acrylate (registered trademark) MTG- A, light acrylate (registered trademark) EHDG-AT, light acrylate (registered trademark) 130A, light acrylate (registered trademark) DPM-A, light ester L (above, Kyoeisha Kagaku Co., Ltd.) Product), Biscot # 190, 2-MTA, MPE400A, MPE550A (above, manufactured by Osaka Yukikagaku Kogyo Co., Ltd.), AM-90G, AM-130G (above, Shin-Nakamura Kagakukyogo (New) Nakayama Chemical Co., Ltd.) is suitable.

<(a-2) hydroxyl group-containing (meth) acrylic monomer>

Copolymer containing the structural unit (2) derived from a highly polar hydroxyl group containing (meth) acryl monomer (a-2) and / or a hydroxyl group containing (meth) acryl monomer (a-2) (a- By containing 3) as a main component (A), the outstanding adhesiveness with respect to optical films, such as a high polarizing polarizing plate, can be ensured, suppressing content of a photoinitiator (B) to a certain degree.

The hydroxyl group-containing (meth) acrylic monomer is a non-amide based monomer which does not contain an amide group, and is typically represented by the following formula (2-1):

Here, in the formula (2-1),

R ₅ is a hydrogen atom or a methyl group,

R ₆ is a divalent organic group.

Although there is no restriction | limiting in particular as a divalent organic group, A C1-C10 alkylene group is suitable. Examples of the alkylene group having 1 to 10 carbon atoms include those mentioned above. Moreover, the said alkylene group may have at least 1 C1-C8 alkyl group, a phenoxyalkyl group (C1-C8 of an alkyl group: C1-C8), a phenoxy group, a phenyl group, or a cyclohexyl group as a substituent. The alkyl group having 1 to 8 carbon atoms can also be appropriately selected from the above.

In the specific examples of the hydroxyl group-containing (meth) acryl monomer (2-1), the hydroxyl group-containing (meth) acrylic monomer (2-1) contained in the main component (A) has a glass transition temperature of the homopolymer. It is preferable to use 20 degrees C or less, Preferably it is -50 degreeC or more and -30 degrees C or less, More specifically, 4-hydroxybutyl (meth) acrylate is especially preferable.

The hydroxyl group-containing (meth) acrylic monomer may be a structure represented by the following formula (2-2) as an amide monomer containing an amide group:

Here, in the formula (2-2),

R ₈ is a hydrogen atom or a methyl group,

R ₉ is a single bond or a divalent organic group,

R ₁₀ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

Although there is no restriction | limiting in particular also as a bivalent organic group, C1-C10 alkylene group is suitable. Moreover, the alkylene group may have at least 1 C1-C8 alkyl group, a phenyl group, or a cyclohexyl group as a substituent. The alkylene group having 1 to 10 carbon atoms is a divalent substituent obtained by removing one hydrogen atom of the alkyl group having 1 to 10 carbon atoms below.

Examples of the alkyl group having 1 to 10 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, isobutyl group, n-hexyl group, 2-hexyl group, and 3-hex Real group, cyclohexyl group, 1-methylcyclohexyl group, n-heptyl group, 2-heptyl group, 3-heptyl group, isoheptyl group, tert-heptyl group, n-octyl group, isooctyl group, tert-octyl group , 2-ethylhexyl group, nonyl group, isononyl group, decyl group and the like are suitable.

In the specific example of the said hydroxyl group containing (meth) acryl monomer (2-2), the hydroxyl group containing (meth) acryl monomer (2-2) which a main component (A) contains has a glass transition temperature of the homopolymer. It is preferable to use 100 degrees C or less, Preferably it is -20 degreeC or more and 100 degrees C or less, More specifically, N-hydroxyethyl (meth) acrylamide is especially preferable.

As mentioned above, as (a-2) component, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, and hydroxymethyl (meth) acryl Latex, 3-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide , N- (1-methyl-2-hydroxyethyl) (meth) acrylamide, N-isopropyl-hydroxy (meth) acrylamide and the like are suitable. Among them, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, and N-hydride from the viewpoint of relatively low glass transition temperature of the homopolymer. Oxyethyl (meth) acrylamide and the like are preferable.

As a commercial item of (a-2) component, BHEA, HPA, HEMA, HPMA (above, Nihon Shokubai Co., Ltd.), 4HBA, CHDMMA (above, Nippon Kasei Co., Ltd.), HEA, HPA, 4-HBA (Above, product made by Osaka Yuki Kagaku Kogyo Co., Ltd.), light ester HOA (N), light ester HOP-A (N), light acrylate (registered trademark) HOB-A (above, Kyoeisha Kagaku Co., Ltd.), HEAA (Registered trademark) (manufactured by KJ Chemical Co., Ltd.), N-MAN (manufactured by Miki Riken Co., Ltd.) and the like.

These (a-2) components can be used individually or in mixture of 2 or more types. In addition, a commercial item may be used for the component (a-2) or a synthetic product may be used.

<The monomer copolymerizable with (a ') (a-1) component and (a-2) component>

The main component (A) may contain a monomer (a ') component copolymerizable with the component (a-1) and the component (a-2) as long as the object effect of the present invention is achieved. As a component (a '), the (meth) acryl monomer (a'-1) which has an amide group (henceforth a "(a'-1) component"), the macromonomer (a'-2) which has a polymeric functional group ( Hereinafter, "it is also called (a'-2) component") and other polymerizable monomer (a'-3) (henceforth also called "(a'-3) component") can be illustrated.

`` (Meth) acrylic monomer having (a'-1) amide group ''

The component (a'-1) is not particularly limited as long as it does not contain a hydroxyl group (non-hydroxyl machine) in the (meth) acryl monomer and has an amide group.

The component (a'-1) is typically represented by the following formula (3):

Here, in the formula (3),

R ₈ ′ is a hydrogen atom or a methyl group,

R ₉ ′ is a single bond or a divalent organic group,

R ₁₀ ′ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms,

R <_11>'is a hydrogen atom, a C1-C10 alkyl group, an acyl group, an epoxy group, a C1-C6 alkoxy group, or a dimethylamino group.

Although there is no restriction | limiting in particular also as a divalent organic group, A C1-C10 alkylene group or an acylene group is suitable. Moreover, the alkylene group or the acyl group may have at least 1 C1-C8 alkyl group, a phenyl group, or a cyclohexyl group as a substituent.

As an alkyl group having 1 to 10 carbon atoms, it is as described above for the formula (2-2).

Although carbon number of an acyl group does not have a restriction | limiting in particular, Preferably it is C1-C18, More preferably, it is C1-C6. In addition, an acyl group shall contain an acetoacetoxy group or an acetyl group.

Examples of the alkoxy group having 1 to 6 carbon atoms include methoxy group, ethoxy group, propyloxy group, isopropyloxy group, butoxy group, sec-butoxy group, tert-butoxy group, isobutoxy group, n-hexyloxy group, 2 -Hexyloxy group, 3-hexyloxy group, cyclohexyloxy group, etc. are suitable.

In addition, R ₁₀ ′ and R ₁₁ ′ may form a ring having 1 to 8 carbon atoms and may have an oxygen atom (ie, an oxygen-containing heterocyclic group) or a sulfur atom (ie, a sulfur-containing heterocyclic group) in the ring. do.

From the above, (meth) acryloyl morpholine, N, N- dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, diacetone (meth) acrylamide, (meth) acrylamide, N , N-dimethylaminopropyl (meth) acrylamide, N-isopropyl (meth) acrylamide, Nn-butoxymethylacrylamide, N-isobutoxymethylacrylamide, N-methoxymethylacrylamide, Nt- Butyl acrylamide etc. are suitable, Especially, from a viewpoint of adhesive improvement, (meth) acryloyl morpholine, N, N- dimethyl (meth) acrylamide, N, N- diethyl (meth) acrylamide, Diacetone (meth) acrylamide, (meth) acrylamide, etc. are preferable. In addition, the amide group-containing (meth) acryl monomer (a'-1) may be N, N'-methylenebis (meth) acrylamide.

Commercially available products of the component (a'-1) include ACMO (registered trademark), DMAPAA (registered trademark), DMAA (registered trademark), NIPAM (registered trademark), DEAA (registered trademark) (above, manufactured by KJ Chemical Co., Ltd.), DAAm (Nipka Kasei Co., Ltd.), NBMA, IBMA, NMMA, TBAA, MBAA (above, MRC Unitech Co., Ltd.), etc. are suitable.

`` (A'-2) polymerizable functional group-containing macromonomer ''

The main component (A) which concerns on this invention may also contain the macromonomer (a'-2) which has a polymeric functional group. The component (a'-2) is a high molecular weight monomer having a polymerizable functional group (unsaturated group), and comprises a polymer chain portion and a polymerizable functional group portion.

Bending resistance (bending resistance) improves because the polymer superposed | polymerized (cured) using such a monomer is contained in an adhesive film. The mechanism is believed to depend on the glass transition temperature of the polymer chain portion of the macromonomer. Specifically, when the glass transition temperature of the polymer chain portion is high, the polymer chain portion forms a hard segment in the pressure-sensitive adhesive film, thereby causing cohesive force on the pressure-sensitive adhesive film. Thereby, it is thought that the adhesive force to a base material improves and bending resistance improves. On the other hand, when the glass transition temperature of the polymer chain | strand part of a macromonomer is low, an adhesive film becomes soft and it is considered that bending resistance improves because followability to a base material becomes high. In addition, the said mechanism is speculative, and this invention is not limited to the said mechanism at all.

As a polymerizable functional group of (a'-2) component, group (ethylenically unsaturated group) which has an ethylenically unsaturated double bond is preferable. Specifically, at least one selected from the group consisting of a vinyl group, an allyl group, a (meth) acryloyl group, and a propenyl group is preferable. It is preferable that a polymerizable group exists at the terminal of a macromonomer, and it is more preferable from a viewpoint of stability at the time of superposition | polymerization that only a polymer terminal exists only at one terminal of a macromonomer. However, a polymeric group may exist as a side chain of a macromonomer, and may exist in the both ends of the chain | strand of a macromonomer.

The polymer chain part of (a'-2) component is methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, stearyl (meth) acrylate, and isobutyl (meth) acryl (Co) whose main structural unit is a repeating unit derived from latex, t-butyl (meth) acrylate, styrene, acrylonitrile, hydroxy (meth) acrylate, ethylhexyl acrylate, dimethylsiloxane, and the like It is preferable that it is a polymer. These polymer chain parts may be comprised by a single repeating unit, and may be comprised by a plurality of repeating units. In addition, when a polymer chain is a copolymer which consists of a some repeating unit, the repeating form is not restrict | limited, Any of an alternating copolymer, a random copolymer, and a block copolymer may be sufficient.

The component (a'-2) is typically represented by the following formula (4):

In the formula (4), R ₁₂ represents a hydrogen atom or a methyl group, and X ₁ represents a single bond or a divalent bond group.

As a bivalent coupling group, a linear, branched or cyclic alkylene group, aralkylene group, arylene group, etc. are mentioned, for example. These may further have substituents, such as a hydroxyl group and a cyano group. As carbon number of the said alkylene group, 1 or more and 10 or less are preferable, and 1 or more and 4 or less are more preferable. As this alkylene group, a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, an octylene group, a decylene group, etc. are mentioned, for example. Among these, methylene group, ethylene group, propylene group, etc. are preferable. As carbon number of the said aralkylene group, 7 or more and 13 or less are preferable. As this aralkylene group, a benzylidene group, a cinnamilide group, etc. are mentioned, for example. As carbon number of the said arylene group, 6 or more and 12 or less are preferable. As this arylene group, a phenylene group, cumenylene group, mesitylene group, tolylene group, xylylene group, etc. are mentioned, for example. Among these, a phenylene group is preferable.

Among the divalent linking groups, it may also be selected from -NR _2- , -COO-, -OCO-, -O-, -S-, -SO ₂ NH-, -NHSO _2- , -NHCOO-, -OCONH- or a heterocycle. Induced groups and the like may be interposed as a bonding group. R <_2> is a hydrogen atom or alkyl groups, such as a methyl group, an ethyl group, and a propyl group.

In Formula (4), X ₂ represents methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, stearyl (meth) acrylate, and isobutyl (meth). A polymer obtained by homopolymerizing or copolymerizing one or two or more monomers selected from acrylate, t-butyl (meth) acrylate, styrene and acrylonitrile, or polysiloxane (polyorganosiloxane) in which an organic group is bonded to a silicon atom ). Among them, X ₂ copolymerizes a polymer obtained by homopolymerizing methyl (meth) acrylate, styrene, n-butyl (meth) acrylate, isobutyl (meth) acrylate, acrylonitrile and styrene, It is preferred that it is a polymer or polyorganosiloxane. In view of durability under high temperature, X ₂ is a polymer obtained by homopolymerizing methyl (meth) acrylate, styrene, isobutyl (meth) acrylate, or a polymer obtained by copolymerizing acrylonitrile and styrene. Particularly preferred. Or, in terms of bending resistance at low temperatures, X ₂ is a polyorganosiloxane is preferred, and particularly preferred, poly-dimethyl-siloxane. In addition, as long as it does not affect the performance of an adhesive, a part of methyl groups of polydimethylsiloxane may be substituted by organic groups (ethyl group, a phenyl group, etc.) other than a hydrogen atom or a methyl group.

Moreover, the said polydimethylsiloxane can be obtained by hydrolyzing and condensing dimethyl dialkoxysilane, such as dimethyldimethoxysilane and dimethyl diethoxysilane. Under the present circumstances, organic groups other than a methyl group can be introduce | transduced into polydimethylsiloxane by using together the alkoxysilane which has organic groups other than a methyl group (for example, diethyl diethoxysilane). In addition to the dialkoxy silane compound, a small amount of a trialkoxy silane compound may be added.

The number average molecular weight (Mn) of the component (a'-2) is preferably in the range of 2000 or more and 20000 or less, more preferably in the range of 2000 or more and 10,000 or less, more preferably in the range of 4000 or more and 8000 or less. More preferred. When number average molecular weight (Mn) is 2000 or more, even if the addition amount of the (a'-2) component at the time of synthesize | combining a copolymer (a-3) can improve the performance of an adhesive. On the other hand, when it is 20000 or less, the viscosity of an adhesive is low and workability | operativity is favorable. The value of the number average molecular weight (Mn) can be controlled by appropriately selecting the amounts of the chain transfer agent and the polymerization initiator to be added to the polymerization system. In addition, in this invention, the number average molecular weight (Mn) of a macromonomer shall employ | adopt the value of polystyrene conversion measured by GPC (gel permeation chromatography) method.

As the component (a'-2), a commercially available product or a synthetic product may be used. When synthesize | combining a component (a'-2), there is no restriction | limiting in particular in the synthesis method, For example, (1) The polymer chain (living polymer anion) which comprises a macromonomer by living anion polymerization is manufactured, and meta A method of reacting with methacrylic chloride or the like; (2) a method of polymerizing a radical polymerizable monomer such as methyl methacrylate in the presence of a chain transfer agent such as mercapto acetic acid to obtain an oligomer having a carboxyl group at its terminal, and then reacting it with glycidyl methacrylate or the like; (3) In the presence of an azo polymerization initiator containing a carboxyl group, a radical polymerizable monomer such as methyl methacrylate is polymerized to obtain an oligomer having a carboxyl group at its terminal, and then macromonomerized with glycidyl methacrylate. Any method, such as a method, can be used.

By manufacturing a macromonomer using the above method, the group as shown below is introduce | transduced as a bivalent coupling group represented by X <_1> in the said Formula (4), for example.

As a commercial item of the component (a'-2), for example, the macromonomer whose terminal is a methacryl group and a polymer chain part is polymethyl methacrylate (PMMA) (product name: 45% AA-6 (AA-6S)) , AA-6; Toagosei Co., Ltd.), Macromonomer whose polymer chain portion is polystyrene (Product name: AS-6S, AS-6; Toagosei Co., Ltd.), Polymer chain portion is styrene / acrylic Macromonomer (Product Name: AN-6S; manufactured by Toagosei Co., Ltd.), a copolymer of nitrile, Macromonomer (Product Name: AB-6; Product manufactured by Toagosei Co., Ltd.), whose polymer chain portion is polybutyl acrylate, Macromonomers of butyl methacrylate (product name: AW-6S; manufactured by Toagosei Co., Ltd.), macromonomers (product name: AK-5; product of Toagosei Co., Ltd.), etc., whose polymer chain portion is polydimethylsiloxane. Moreover, these macromonomers may be used independently or may be used together 2 or more types.

`` (A'-3) other polymerizable monomers ''

Specific examples of the other polymerizable monomer copolymerizable with the component (a-1) and the component (a-2) include epoxy groups such as glycidyl (meth) acrylate and methylglycidyl (meth) acrylate, for example. Acrylic monomers; Amino groups such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, N-tert-butylaminoethyl (meth) acrylate, and 2-((meth) acryloxy) ethyltrimethylammonium chloride (Meth) acrylic monomers having; (Meth) acryl monomer which has urethane groups, such as urethane (meth) acrylate; (meth) acrylvinyl monomers having phenyl groups such as p-tert-butylphenyl (meth) acrylate and o-biphenyl (meth) acrylate; Vinyl monomers having silane groups such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethyl) silane, vinyltriacetylsilane and methacryloyloxypropyltrimethoxysilane; Styrene, chloro styrene, α-methyl styrene, vinyl toluene, vinyl chloride, vinyl acetate, vinyl propionate, acrylonitrile, vinyl pyridine and the like. These other monomers may be used independently or may be used in combination of 2 or more type.

<< content of each component in the form of said (1) >>

It is preferable that content of (a-1) component is 70 mass% or more with respect to the total amount of main component (A) from a viewpoint of making glass transition temperature after hardening low. If the upper limit of content of (a-1) component is 99.9 mass% or less, since it is excellent in various durability, excellent in bending resistance at high temperature, and the adhesive force at high temperature improves, it is preferable. The content of the component (a-1) is more preferably 75% by mass or more and 95% by mass or less from a viewpoint of securing excellent adhesion while lowering the glass transition temperature after curing of the pressure-sensitive adhesive composition, and is 75% by mass or more and 90% by mass. 80 mass% or more and 90 mass% or less are more preferable.

From the viewpoint of lowering the glass transition temperature after curing, the component (a-1-1) in the component (a-1) is 70% by mass or more and 99.5% by mass or less with respect to the total amount of the main component (A), preferably 75 Mass% or more and 95 mass% or less, 75 mass% or more and 90 mass% or less, 80 mass% or more and 90 mass% or less are preferable.

From the viewpoint of lowering the glass transition temperature after curing, the component (a-1-2) in the component (a-1) is 0% by mass or more and 30% by mass or less, preferably 1% by mass based on the total amount of the main component (A). 15 mass% or more, 1 mass% or more and 10 mass% or less, 1 mass% or more and 5 mass% or less are preferable.

It is preferable that content of (a-2) component is 0.1 mass% or more and 30 mass% or less with respect to the whole quantity of a main component (A) from a viewpoint of adhesive improvement and durability improvement, 5 mass% or more and 25 mass% or less, It is more preferable that they are 10 mass% or more and 25 mass% or less, and 10 mass% or more and 20 mass% or less.

It is preferable that content of the monomer of Formula (2-1) in (a-2) component is 0.1 mass% or more and 30 mass% or less with respect to whole quantity of a main component (A) from a viewpoint of adhesive improvement and durability improvement, It is more preferable that they are 5 mass% or more and 20 mass% or less, and 10 mass% or more and 20 mass% or less.

Content of the monomer of Formula (2-2) in (a-2) component is 0 mass% or more and 10 mass% or less and 0.1 mass% with respect to whole quantity of a main component (A) from a viewpoint of adhesive improvement and durability improvement. It is preferable that it is 10 mass% or more, and it is more preferable that they are 0.1 mass% or more and 5 mass% or less, 0.1 mass% or more and 3 mass% or less, 0.1 mass% or more and 1 mass% or less.

It is preferable that content of (a ') component is 0 mass% or more and 10 mass% or less with respect to the whole quantity of a main component (A). From the viewpoint of sufficiently securing the amounts of the component (a-1) and the component (a-2), the content of the component (a ') is more preferably 0% by mass or more and 5% by mass or less.

`` Form of (2) above ''

As one aspect which concerns on this invention, the main component (A) is a structure derived from the structural unit (1) and (a-2) component derived from (a-1) component, (a-2) component, and (a-1) component The form containing the copolymer (a-3) containing a unit (2) (henceforth only a copolymer (a-3)) (the form which a curable compound consists of a monomer and a polymer) is mentioned. In this embodiment, in the raw material monomer of the copolymer (a-3), the (a-1) component, the (a-2) component and the (a ') component added as necessary are the copolymer (a -3) in the form of a so-called polymer syrup, which is a solvent for dissolving.

Suitable content of the component (a-1), the component (a-2) and the component (a ') in the form of (2) is &quot; content of each component in the form of (1) &quot; Since it is the same as the suitable content described in, description is omitted here. In addition, suitable content of (a-1) component, (a-2) component, and (a ') component here refers to content before copolymerizing the one part. The suitable content of the unreacted component (a-1), the component (a-2) and the component (a ') after copolymerizing a part thereof is determined by the amount used for copolymerization (the following copolymer (a-3) It can be said that the range except content range and the range except the ratio of each structural unit which comprises copolymer (a-3) of a nucleus) is preferable.

In addition, suitable content of each structural unit of the copolymer (a-3) contained in the form of (2) is each component described in the term of <content of each component in the form of said (1) >> (( Suitable content of a-1) component, (a-2) component, (a ') component) is applied as it is.

That is, the copolymer (a-3) contained in the form of (2) is 70 mass% or more and 99.9 mass% or less of the structural unit derived from a (meth) acrylic acid ester monomer (a-1), and hydroxyl group containing (meth 0.1 mass% or more and 30 mass% or less of the structural unit derived from an acrylic monomer (a-2), and 0 mass of structural units derived from the monomer ((a ') which can copolymerize with (a-1) component and (a-2) component. It is preferable to contain% or more and 10 mass% or less (However, the total amount of the structural unit derived from the said (a-1) component, (a-2) component, and (a ') component is 100 mass%.) The copolymer (a-3) contained in the form of) is more preferably 75% by mass or more and 95% by mass or less of a structural unit derived from a (meth) acrylic acid ester monomer (a-1), and a hydroxyl group-containing ( 5 mass% or more and 25 mass% or less of the structural unit derived from a meta) acryl monomer (a-2), and the structural unit 0 derived from the monomer ((a ') which is copolymerizable with a component (a-1) and a component (a-2). % By mass 5 or more Mass% or less (However, the total amount of the said (a-1) component, (a-2) component, and the structural unit derived from (a ') contains 100 mass%).

In the form of (2), content of the copolymer (a-3) with respect to the total amount (gross mass) of a main component (A) has favorable applicability | paintability to the to-be-adhered body of adhesive composition, and durability and folding resistance are From a viewpoint of being excellent, they are 4 mass% or more and 20 mass% or less, More preferably, they are 6 mass% or more and 12 mass% or less. Content of this copolymer (a-3) can be controlled by controlling a polymerization rate etc. in the block polymerization method using the photoinitiator mentioned later, for example.

[Production of Copolymer (a-3)]

In the aspect of the above (2), the method for producing the copolymer (a-3) which can be included in the main component (A) is not particularly limited, and a solution polymerization method using a polymerization initiator, a bulk polymerization method, and an emulsion polymerization Conventionally well-known methods, such as a method, suspension polymerization method, reverse phase suspension polymerization method, thin film polymerization method, and spray polymerization method, can be used. As a method of polymerization control, adiabatic polymerization method, temperature controlled polymerization method, isothermal polymerization method, etc. are mentioned. As the polymerization initiator, any of a thermal polymerization initiator and a photopolymerization initiator may be used. Further, in addition to or in addition to the method of initiating polymerization by the polymerization initiator, a method of initiating polymerization by irradiating active energy rays such as radiation, electron beams, and ultraviolet rays may be employed. Among them, a solution polymerization method using a thermal polymerization initiator or a bulk polymerization method using a photopolymerization initiator is more preferable because the molecular weight can be easily controlled and impurities can be reduced. That is, in the step of preparing the copolymer (a-3) that can be included in the main component (A) as shown in the examples, it is not necessary to use a predetermined photopolymerization initiator (B) as the polymerization initiator, but may be used. In the aspect of the above (2), the pressure-sensitive adhesive composition by adding a predetermined photopolymerization initiator (B) to the main component (A) obtained by the method for producing the copolymer (a-3) that can be included in the main component (A). It can form. That is, the photopolymerization initiator (B) is used in the step of curing the pressure-sensitive adhesive composition to form the pressure-sensitive adhesive film, and the photopolymerization initiator (B) does not necessarily need to be used in the step of preparing the copolymer (a-3) which may be included in the main component (A). (See Examples). Of course, even when preparing the copolymer (a-3) which can be contained in the main component (A), you may use the predetermined photoinitiator (B).

In one Embodiment of the adhesive composition of this invention, a copolymer (a-3) contains the said (meth) acrylic acid ester monomer (a-1) and the said hydroxyl group containing (meth) acryl monomer (a-2). It is superposed | polymerized by solution polymerization of the reaction liquid to make. As a solution polymerization method using a thermal polymerization initiator, for example, the thermal polymerization initiator with respect to 100 mass parts of total amounts of the raw material monomer of a copolymer (a-3) using ethyl acetate, toluene, methyl ethyl ketone, etc. as a solvent. Preferably, 0.01 mass part or more and 1 mass part or less are added, and it makes it react for 3 hours or more and 10 hours or less in nitrogen atmosphere, for example at reaction temperature 40 degreeC or more and 90 degrees C or less (or 60 degreeC or more and 90 degrees C or less). A method is mentioned.

Examples of the thermal polymerization initiator include 2,2-azobisisobutyronitrile (AIBN), 2,2'-azobis (2-methylbutyronitrile), azobiscyano valeric acid, 2 , 2'-azobis (4-methoxy-2.4-dimethylvaleronitrile), 2,2'-azobis (2.4-dimethylvaleronitrile), dimethyl 2,2'-azobis ( 2-methylpropionate), 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis [ N- (2-propenyl) -2-methylpropionamide], 2,2'-azobis (N-butyl-2-methylpropionamide), 2,2'-azobis [2- (2-imida Zolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] disulfate dihydrate, 2,2'-azobis (2- Methylpropionamidine) dihydrochloride, 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate, 2,2'-a Bis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis (1-imino-1-pyrrolidino-2-methylpropane) dihydrochloride, 2,2 ' Azo compounds such as azobis [2-methyl-N- (2-hydroxyethyl) propionamide]; tert-butylperoxy pivalate, tert-butylperoxybenzoate, tert-butylperoxy-2-ethylhexanoate, di-tert-butylperoxide, cumene hydroperoxide, benzoyl peroxide, tert-butylhydride Organic peroxides such as loperoxide; Inorganic peroxides, such as hydrogen peroxide, ammonium persulfate, potassium persulfate, and sodium persulfate, are mentioned. These thermal polymerization initiators may be used alone or in combination of two or more thereof. The obtained copolymer (a-3) is added to the component (a-1) and the component (a-2) to form the component (a-1), the component (a-2) and the copolymer (a-3). Main component (A) (polymer syrup) can also be obtained (form (2)).

Although it does not restrict | limit especially as a block polymerization method using a photoinitiator, For example, the raw material monomer of a copolymer (a-3) and a photoinitiator are added, and reaction start temperature is usually 20 degreeC or more and 35 degrees C or less in nitrogen atmosphere. The active energy ray is irradiated. In the step in which the temperature in the reaction system rises from 5 ° C to 15 ° C from the reaction start temperature, a method of stopping the reaction by introducing air into the reaction system and the like to obtain a copolymer (a-3) is mentioned. At this time, it is not necessary to react all the raw material monomers to be used, and what is necessary is just to stop reaction at the stage which became desired polymerization conversion ratio (= moderate viscosity). According to this method, the component (a-1), the component (a-2) and the component (a ') added as necessary as the unreacted raw material monomer become solvents for dissolving the copolymer (a-3). The main component (A) (polymer syrup) containing the component (a-1), the component (a-2) and the copolymer (a-3) can be obtained (form (2) above).

Examples of active energy rays used in the bulk polymerization method include ultraviolet rays (UV), visible light, laser rays, α rays, β rays, γ rays, X rays, electron beams, and the like. In terms of cost, ultraviolet rays are suitably used. That is, in one preferable embodiment of the adhesive composition of this invention, a copolymer (a-3) is the said (meth) acrylic acid ester monomer (a-1) and the said hydroxyl group containing (meth) acryl monomer (a-2) It is polymerized by ultraviolet irradiation of the reaction liquid containing). More preferably, ultraviolet rays with a wavelength of 200 nm or more and 400 nm or less are used. An ultraviolet-ray can be irradiated using light sources, such as a high pressure mercury lamp, a microwave excitation lamp, a chemical lamp, and black light. The roughness is preferably 0.1 mW / cm ² or more and 20.0 mW / cm ² or less.

Examples of the photopolymerization initiator include acetophenone, 3-methylacetophenone, benzyldimethyl ketal, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1- (4-isopropylphenyl) -2 -Hydroxy-2-methylpropan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-hydroxy-2-methyl-1 Acetophenones such as -phenylpropan-1-one; Benzophenones including benzophenone, 4-chlorobenzophenone and 4,4'-diaminobenzophenone; Benzoin ethers such as benzoin propyl ether and benzoin ethyl ether; Thioxanthones such as 4-isopropyl thioxanthone; 1-hydroxycyclohexylphenyl ketone, xanthone, fluorenone, camphorquinone, benzaldehyde, anthraquinone and the like. These photoinitiators can be used individually or in mixture of 2 or more types.

A photoinitiator may use a commercial item, As an example of a commercial item, Irgacure (trademark) 127, 184, 819, 907, 651, 1700, 1800, 819, 369, 261, DAROCUR (registration) Trademark) TPO, Tarocure (registered trademark) 1173 (above, BASF Japan Corporation), Ezacure (registered trademark) KIP150, TZT (above, DKSH Japan Corporation), Kayakure (KAYACURE) (registered trademark) BMS, DMBI (above, Nihon Kayaku Co., Ltd. product) etc. are mentioned.

The usage-amount of a photoinitiator becomes like this. Preferably it is 0.0005 mass part or more and 1 mass part or less, More preferably, it is 0.002 mass part or more and 0.5 mass part or less with respect to 100 mass parts of total amounts of the raw material monomer of a copolymer (a-3).

In addition, in the synthesis | combination of a copolymer (a-3), in order to adjust molecular weight, you may use a chain transfer agent. For example, methyl mercaptan, t-butyl mercaptan, decyl mercaptan, benzyl mercaptan, lauryl mercaptan, stearyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, mercaptoacetic acid, mercapto Mercaptans such as propionic acid and esters thereof, 2-ethylhexyl thioglycol and octyl thioglycolate; Alcohols such as methanol, ethanol, propanol, n-butanol, isopropanol, t-butanol, hexanol, benzyl alcohol and allyl alcohol; Halogenated hydrocarbons such as chloroethane, fluoroethane and trichloroethylene; Carbonyls such as acetone, methyl ethyl ketone, cyclohexanone, acetophenone, acetaldehyde, propionaldehyde, n-butylaldehyde, furfural and benzaldehyde; Methyl-4-cyclohexene-1,2-dicarboxylic acid anhydride, (alpha) -methylstyrene, etc. are mentioned. These may be used independently or may be used together 2 or more types.

In the present invention, the weight average molecular weight (Mw) of the copolymer (a-3) is preferably 1 million or more and 2.5 million or less, and more preferably 1.2 million or more and 2.1 million or less. If the weight average molecular weight is 1 million or more, it is excellent in suppressing the occurrence of durability, peeling and lifting, and the adhesiveness is improved. Moreover, if it is 2.5 million or less, the viscosity of a copolymer solution will become moderate and workability, such as coating property, will improve.

In the present invention, the glass transition temperature of the copolymer (a-3) is preferably less than -57.0 ° C, more preferably -59.0 ° C or less. Preferably, the minimum of the glass transition temperature of the copolymer (a-2) of this invention is -100 degreeC, More preferably, it is -80 degreeC. In the above range, even when the pressure-sensitive operation of the pressure-sensitive adhesive film at a low temperature and high temperature does not cause peeling or lifting, the folding resistance under both high and low temperature conditions is excellent.

[Photopolymerization Initiator (B)]

The adhesive composition which concerns on this invention contains a predetermined photoinitiator (B). Specifically, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) and 2-hydroxy-1- {4- [4- (2-hydroxy -2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propane-1-one. A photoinitiator (B) may use a commercial item, As an example of a commercial item, Irgacure (trademark) 127 (made by BASF Japan Corporation), Ezacure (registered trademark) KIP150 (made by DKSH Japan Corporation), Ezacure (Registered trademark) one (made by DKSH Japan Co., Ltd.), etc. are mentioned. In the adhesive composition which concerns on this invention, the main component (A) which consists of a curable compound containing the said acryl-type compound is combined with the said specific photoinitiator (B), and the glass transition temperature after hardening of an adhesive composition is adjusted to less than -57.0 degreeC, By controlling, while suppressing content of a photoinitiator (B) to a certain extent, folding resistance can be improved, Furthermore, the weight loss rate of the adhesive composition under high temperature can be made small, and abnormal odor and outgassing can be suppressed effectively. It is excellent in that it is.

In addition, by suppressing the content of the predetermined photopolymerization initiator (B) to a certain degree, the hardness of the pressure-sensitive adhesive composition formed by curing the pressure-sensitive adhesive composition is excessively increased, and the adhesion and durability can also be prevented from being lowered. In detail, it is preferable to make content of the said photoinitiator (B) into 0.05 mass part or more and 1.0 mass part or less with respect to 100 mass parts of main components (A). Thereby, in addition to the said effect, when the main component (A) is the form of a polymer syrup, it is excellent at the point which carries out a final copolymerization reaction and becomes easy to form an adhesive film. As for the addition amount at the time of adding such a photoinitiator (B), 0.1 mass part or more and 1.0 mass part or less are more preferable with respect to 100 mass parts of main components (A).

Moreover, it is preferable that it is 300 or more, and, as for the number average molecular weight (Mn) of a photoinitiator (B), it is more preferable that it is 400 or more. When the number average molecular weight (Mn) is 300 or more, it is excellent in solubility in the main component (A), and excellent in suppressing the generation of durability, peeling and lifting, adhesion is improved, and abnormal odor and outgas generation are suppressed. can do. In addition, the upper limit of the number average molecular weight (Mn) of a photoinitiator (B) is not specifically limited, When the effect of this invention can be expressed effectively, it is contained in the technical scope of this invention. In addition, the number average molecular weight (Mn) of a photoinitiator (B) can be measured by mass spectrometry.

[Bridge]

The adhesive composition of this invention can contain a crosslinking agent further. The content at the time of adding a crosslinking agent produces an optimal value extensively according to the kind of crosslinking agent to be used. For example, the crosslinking agent used by the Example and comparative example which are mentioned later is one of the smallest effects, and even 0.2 mass part (addition amount in an Example) with respect to 100 mass parts of main components (A), It can fully exhibit the effect. In addition, although it does not enumerate in an Example, in the experiment of this inventor, it is prescribed | regulated uniquely, for example, there exists a crosslinking agent which cannot obtain an effect about 10 mass parts with respect to 100 mass parts of main component (A), for example. It can't be done. As a rough target, it is the range of 0.0001 mass part or more and 15 mass parts or less with respect to 100 mass parts of main components (A). It is preferable to confirm and use the optimal range suitable for each crosslinking agent through the preliminary experiment etc. in the said target range. By using it in the optimum range suitable for each crosslinking agent, a gelation rate can be improved and there exists a technical effect of both adhesiveness and bending resistance.

The kind of crosslinking agent which can be used for the adhesive composition of this invention is not specifically limited, A vinyl compound (so-called acrylic crosslinking agent), an isocyanate compound, a carbodiimide compound, an oxazoline compound, an epoxy compound, a polyfunctional acrylic acid ester It is preferable that it is at least 1 sort (s) chosen from the group which consists of a monomer, a peroxide, a titanium coupling agent, a zirconium compound, an aluminum chelate compound, and a thermal acid generator. In particular, the crosslinking agent is more preferably at least one selected from the group consisting of vinyl compounds (so-called acrylic crosslinking agents), isocyanate compounds, carbodiimide compounds, oxazoline compounds, epoxy compounds, and peroxides, and furthermore, adhesion From the standpoint of the properties and the durability, it is more preferable to be at least one of a vinyl compound (so-called acrylic crosslinking agent), an isocyanate compound, and a peroxide.

Moreover, the crosslinking agent which concerns on this invention includes what forms a crosslinked structure by itself (hardening agent type), and also includes the thing which accelerates a crosslinking reaction (curing catalyst type) although it does not form a crosslinking structure by itself. In particular, the latter are peroxides and thermal acid generators.

(Vinyl compound (so-called acrylic crosslinking agent))

As a vinyl compound (so-called acrylic crosslinking agent) suitably used as a crosslinking agent, acrylic acid or methacrylic acid which has two or more polymerizable unsaturated bonds in a molecule | numerator, derivatives thereof, etc. are mentioned, In particular, acryloyl group is contained in a molecule | numerator. It is preferable that it is a compound (henceforth also called "acrylic-acid derivative") which has two or more, and it is preferable that the density | concentration of the said acrylic acid derivative is made into the range of 0.001-0.2 mol / kg by the mass molar concentration of the said acryloyl group. .

Moreover, according to molecular weight, the thing of (A) low molecular weight whose molecular weight is less than 4,000 and the thing of (B) high molecular weight whose molecular weight is 4,000 or more are mentioned as an acrylic acid derivative, and it classifies below and demonstrates respectively.

The molecular weight (a) of less than 4,000 as having a low molecular weight is bisphenol A diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, and 1,9-nonanediol di Acrylate, 1,3-butylene glycol diacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate, glycerol diacrylate, neopentyl glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate Acrylate, polybutylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, tris (acryloxyethyl) isocyanurate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylic Latex, dipentaerythritol hexaacrylate, dipenta Acrylate monomers such as discrete erythritol pentaacrylate; Although acryl oligomers, such as an epoxy acrylate, polyester acrylate, urethane acrylate, and an acryl acrylate, etc. are mentioned, Trimethylol propane triacrylate, pentaerythritol triacrylate, and tris (acryloxyethyl) isocyanu Preferred are acrylates such as latex, pentaerythritol tetraacrylate, and dipentaerythritol tetraacrylate. In addition, among the compounds having two or more polymerizable unsaturated bonds described above in the molecule, those having two or more acryloyl groups in the molecule can be appropriately selected and used. As a commercial item which the said (a) molecular weight is less than 4,000, A-TMM-3, A-TMM-3L, A-TMM-3LM-N, ATM-35E, A-TMMT, A-9550, A-DPH (above, new Nakamura Kagakukyo Co., Ltd., PETIA, PETRA, EBECRYL (registered trademark) 40, EBECRYL (registered trademark) 180, DPHA (above, DAICEL-ALLNEX LTD.), Light acrylate (registered trademark) ) PE-3A, light acrylate (registered trademark) PE-4A, light acrylate (registered trademark) DPE-6A (above, Kyoeisha Kagaku Co., Ltd.), Miramer M340, Miramer M4004, Miramer M600 (above, Toyo Chemicals) Co., Ltd.) may be exemplified.

(B) A molecular weight of 4,000 or more as a high molecular weight is a high molecular weight compound having two or more reactive unsaturated bonds (hereinafter referred to as a "high molecular weight crosslinking agent"), preferably having a weight average molecular weight of 4,000 to 20,000, It is more preferable that they are 8,000-16,000. When the molecular weight of a high molecular weight crosslinking agent exceeds 20,000, the viscosity of an adhesive composition will become high too much and a sheet preparation will become difficult. As high molecular weight crosslinking agent, following (a)-(e) which uses alkylene glycol as a raw material from the point of compatibility with the other adhesive composition material before hardening of an adhesive composition is mentioned preferably.

As a vinyl compound (so-called acryl-type crosslinking agent) used suitably as a crosslinking agent which uses alkylene glycol as a raw material, the following are mentioned.

(a) di (meth) acrylates of dialcohol compounds; The di (meth) acrylate of a dialcohol compound can be obtained by making polyalkylene glycol, such as polyethyleneglycol, polypropylene glycol, polybutylene glycol, and acrylic acid or methacrylic acid react, for example.

(b) di (meth) acrylates of epoxy resins; The di (meth) acrylate of an epoxy resin is an epoxy resin which has two epoxy groups in the molecule | numerators, such as diglycidyl ether of polyalkylene glycol, such as polyethyleneglycol, polypropylene glycol, and a polybutylene glycol, for example. It can obtain by making it react with acrylic acid or methacrylic acid.

(c) di (meth) acrylates of polyester whose both ends are hydroxyl groups; The di (meth) acrylate of the polyester whose both ends are hydroxyl groups is produced by making a polyester polyol react with saturated acid and a polyhydric alcohol in detail. Examples of the saturated acid include aliphatic dicarboxylic acids such as azelaic acid, adipic acid and sebacic acid, and examples of the polyhydric alcohol include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, butylene glycol, polyethylene glycol, and polypropylene glycol. There is this. By reacting such polyester polyol and acrylic acid or methacrylic acid, di (meth) acrylate of polyester can be obtained.

(d) di (meth) acrylates of polyurethanes; Polyurethane's di (meth) acrylate is obtained by making a polyurethane react with a polyhydric alcohol compound and a polyhydric isocyanate compound. Examples of the polyhydric alcohol include propylene glycol, tetramethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 2- Methyl-1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, poly 1,2-butylene glycol, polypropylene glycol, polytetramethylene glycol, ethylene glycol -Propylene glycol block copolymer, ethylene glycol tetramethylene glycol copolymer, methylpentanediol modified polytetramethylene glycol, propylene glycol modified polytetramethylene glycol, propylene oxide adduct of bisphenol A, propylene oxide addition of hydrogenated bisphenol A Sieve, propylene oxide adduct of bisphenol F, propylene oxide adduct of hydrogenated bisphenol F, and the like. As a polyvalent isocyanate compound, tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate , Tetramethylxylylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate Diisocyanates such as anate, norbornene diisocyanate, polymers of the diisocyanates described above, or urea modifications and burette modifications of the diisocyanates.

These polyhydric alcohols and polyhydric isocyanate can be used individually by 1 type or in combination of 2 or more types, respectively.

As such a polyurethane, the di (meth) acrylate of a polyurethane can be obtained by making the compound which has a hydroxyl group in the terminal obtained by making it react with excess polyhydric alcohol with acrylic acid or methacrylic acid.

(e) a compound obtained by reacting a polyurethane with a compound having a hydroxyl group and a reactive double bond (hereinafter also referred to as "reactive double bond terminal polyurethane"); A reactive double bond terminal polyurethane can be obtained by reacting the compound which has an isocyanate group in the terminal obtained by excessively reacting polyvalent isocyanate with the compound which has a hydroxyl group and a reactive double bond. The compound which has an isocyanate group in the terminal obtained by making the polyhydric isocyanate react excessively uses the same thing as the polyhydric alcohol compound and polyhydric isocyanate compound which become a raw material of polyurethane as described in said (d). You can get it by

Examples of the compound having a reactive double bond with a hydroxyl group include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, polyethylene glycol monoacrylate, Polypropylene glycol monoacrylate, ethylene glycol propylene glycol block copolymer monoacrylate, ethylene glycol tetramethylene glycol copolymer monoacrylate, caprolactone-modified monoacrylate (brand name: Plaque Cell FA series, Daicel Kagaku Corporation Products), acrylic acid derivatives such as pentaerythritol triacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, Polyethylene Glycol Monomethacrylate, Polypropylene Glycol Monomethacrylate, ethylene glycol propylene glycol block copolymer monomethacrylate, ethylene glycol tetramethylene glycol copolymer monomethacrylate, caprolactone-modified monomethacrylate (brand name: Plaque Cell FA series, Daiselkaga Methacrylic acid derivatives, such as the Co. company make, pentaerythritol trimethacrylate, etc. are mentioned. These compounds are used individually by 1 type or in combination of 2 or more types.

(B) A high molecular weight crosslinking agent as a crosslinking agent having a molecular weight of 4,000 or more, in terms of toughness of the cured product in the above (a) to (d), (d) a di (meth) acrylate of polyurethane and (e) a reactive double bond Terminal polyurethanes (particularly those in which the reactive double bonds are based on acryloyl groups) are preferred.

Moreover, among these, it is more preferable that the diol component of a polyurethane consists of polypropylene glycol and polytetramethylene glycol, The diol component is polypropylene glycol and polytetramethylene glycol, and the diisocyanate component is isophorone. Particular preference is given to using polyurethanes which are diisocyanates.

When the compatibility between the main component (A) and the high molecular weight crosslinking agent is low, when the amount of the high molecular weight crosslinking agent is increased, the cured product becomes cloudy, but the compatibility with the main component (A) is obtained by using alkylene glycol as the raw material of the high molecular weight crosslinking agent. It can improve and can maintain transparency regardless of the quantity of a high molecular weight crosslinking agent.

Moreover, when a high molecular weight crosslinking agent is used as a vinyl compound (so-called acrylic crosslinking agent) suitably used as a crosslinking agent, hardened | cured material may be prevented from falling down and adhesive force becomes low too much even when it uses in comparatively large quantity. Thereby, the usage-amount of a crosslinking agent can be increased and it can suppress that the characteristic of hardened | cured material changes by the error at the time of compounding.

As a synthesis method of the high molecular weight crosslinking agent, known polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization can be used.

The above high molecular weight crosslinking agent can be used individually or in combination of 2 or more types.

It is preferable that the vinyl compound (so-called acrylic crosslinking agent) used suitably as a crosslinking agent contains 0.001-0.2 mol / kg by mass molar concentration of acryloyl group.

As a compounding quantity of the vinyl compound (so-called acryl-type crosslinking agent) used suitably as a crosslinking agent, it is more preferable that it is 0.001-0.2 mol / kg by mass mass concentration of acryloyl group, It is still more preferable that it is 0.005-0.1 mol / kg, 0.01 Particularly preferred is from 0.08 mol / kg.

When the density | concentration of the vinyl compound (so-called acrylic crosslinking agent) used suitably as a crosslinking agent is less than 0.001 mol / kg by the mass molar concentration of acryloyl group, it may become difficult for the hardened | cured material of an adhesive composition to maintain a shape, and conversely When it exceeds 0.2 mol / kg, adhesive force may become small, or a problem may arise in wet heat reliability. Moreover, the hardened | cured material of an adhesive composition may recede and a problem may arise easily in a mechanical characteristic.

As a vinyl compound (so-called acrylic crosslinking agent) suitably used as a crosslinking agent, a polymerizable unsaturated bond such as acrylonitrile, styrene, vinyl acetate, ethylene, propylene, or the like, in addition to a compound having two or more acryloyl groups in the molecule The compound which has one in it can be used.

In order to acquire the effect of this invention, in the whole quantity of the polymeric compound used as a vinyl compound (so-called acrylic crosslinking agent) used suitably as a crosslinking agent, monomers other than the compound which has two or more acryloyl groups in a molecule (the said polymerizable property) 90 mass% or less is preferable, as for the usage-amount of the compound which has one unsaturated bond in a molecule | numerator, 50 mass% or less is more preferable, and its 20 mass% or less is still more preferable.

Moreover, as a vinyl compound (so-called acrylic crosslinking agent) used suitably as a crosslinking agent, the compound which has two or more acryloyl groups in a molecule | numerator, and the compound which has two or more polymerizable unsaturated bonds in a molecule can be used together. When there are too many compounds which have two or more polymerizable unsaturated bonds in a molecule | numerator, there exists a tendency for adhesive force to become small too much and to easily tear an adhesive sheet by an impact.

(Isocyanate Compound)

It is an isocyanate compound suitably used as a crosslinking agent, It does not specifically limit, For example, a trimethylol-propantolylene diisocyanate, a triaryl isocyanate, a dimer acid diisocyanate, 2 , 4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 1,4-phenylene diisocyanate, xylylene diisocyanate (XDI), tetramethylxylidenediisocyanate (TMXDI), tolidine diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI), hexamethylene diisocyanate ( HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, Bonanediisocyanatomethyl (NBDI), transcyclohexane 1,4-diisocyanate, isophorone diisocyanate (IPDI), H6-XDI (hydrogenated XDI), H12-MDI (hydrogenated MDI), Carbodiimide-modified diisocyanates of the diisocyanates, or isocyanurate-modified diisocyanates thereof; and the like, and these may be used alone or in combination of two or more thereof. Moreover, you may use together with the peroxide mentioned later. Adducts of polyol compounds such as the above isocyanate compound and trimethylolpropane, and the beret body and isocyanurate body of these isocyanate compounds can also be suitably used.

In addition, a commercial item or a synthetic product may be used for an isocyanate compound. As a commercial item, Coronate (registered trademark) L, Coronate (registered trademark) HL, Coronate (registered trademark) HX, Coronate (registered trademark) 2030, Coronate (registered trademark) 2031 (for example) Nippon Polyurethane Co., Ltd.), Takeate (registered trademark) D-102, Takeate (registered trademark) D-110N, Takeate (registered trademark) D-200, Takenate (registered trademark) D -202 (above, Mitsui Chemical Co., Ltd.), DURANATE (registered trademark) 24A-100, Duranate (registered trademark) TPA-100, Duranate (registered trademark) TKA-100, Duranate (registered trademark) ) P301-75E, Duranate® E402-90T, Duranate® E405-80T, Duranate® TSE-100, Duranate® D-101, Duranate® ) D-201 (above, Asahi Kasei Chemical Co., Ltd.), Sumidule (registered trademark) N-75, N-3200, N-3300 (above, Sumika Bayer urethane Co., Ltd.) G) and the like. Among them, Coronate (registered trademark) L, Coronate (registered trademark) HL, Coronate (registered trademark) HX, Takenate (registered trademark) D-110N, Duranate (registered trademark) 24A-100, Duranate ( Trademark) TPA-100 is preferred, and more preferred are Coronate® L, Coronate® HX, and Duranate® 24A-100.

(Carbodiimide compound)

As a carbodiimide compound suitably used as a crosslinking agent, it is not specifically limited, For example, those of Paragraph "0039"-"0046" of Unexamined-Japanese-Patent No. 2012-246444, or what modified them suitably Can be mentioned.

(Oxazoline compound)

It does not specifically limit as an oxazoline compound used suitably as a crosslinking agent, For example, those described in Paragraph "0037" of Unexamined-Japanese-Patent No. 2015-087539, or what modified them suitably are mentioned.

(Epoxy compound)

Arbitrary suitable epoxy crosslinking agents can be employ | adopted as an epoxy crosslinking agent (epoxy compound) used suitably as a crosslinking agent. For example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerine diglycidyl ether, neo Pentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, tetraglycidyl xylene diamine, trimethylolpropane polyglycidyl ether, diglycerol polyglycidyl Tere, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether and the like can be used.

As a commercial item, For example, Adekaresin (registered trademark) of TETRAD (trademark) C, Tetrad (trademark) X of Mitsubishi Kasuga Gaku Co., Ltd. product, Adeka (ADEKA) product ) EPU series, Adeka resin (registered trademark) EPR series, CELLOXIDE (registered trademark) made from Daicel Corporation, etc. are mentioned. In particular, such liquid epoxy resins are preferable in that the pressure-sensitive adhesive mixing operation when producing the pressure-sensitive adhesive film becomes easy.

(peroxide)

A peroxide suitably used as a crosslinking agent can be used as long as it can generate radicals by heating to achieve crosslinking of the pressure sensitive adhesive. However, in view of workability and stability, the half-life temperature is preferably 80 ° C or higher and 160 ° C for 1 minute. Hereinafter, More preferably, it is preferable to use peroxide of 90 degreeC or more and 140 degrees C or less. On the other hand, the half-life of the peroxide is an index indicating the decomposition rate of the peroxide, which is a time at which the peroxide decomposition amount is halved, and regarding the decomposition temperature for obtaining the half-life at any time and the half-life at any temperature, the manufacturer It is described in a catalog and the like, and is described in, for example, the organic peroxide catalog ninth edition (May 2003) issued by Nihon Yushi Co., Ltd. (Nichiyu Co., Ltd.).

As such a peroxide, bis (2-ethylhexyl) peroxydicarbonate (1 minute half life temperature 90.6 degreeC), bis (4-t-butyl cyclohexyl) peroxy dicarbonate (1 minute half life temperature 92.1 degreeC), bis-sec Butyl peroxydicarbonate (1 minute half life temperature 92.4 ° C.), t-butyl peroxy neodecanoate (1 minute half life temperature 103.5 ° C.), t-hexyl peroxy pivalate (1 minute half life temperature 109.1 ° C.), t Butyl peroxy pivalate (half life temperature 110.3 ° C.), dilauroyl peroxide (half life temperature 116.4 ° C.), bis-n-octanoyl peroxide (half life temperature 117.4 ° C.), 1,1, 3,3-tetramethylbutylperoxy-2-ethylhexanoate (1 minute half-life temperature 124.3 ° C), bis (4-methylbenzoyl) peroxide (1 minute half-life temperature 128.2 ° C), dibenzoylperoxide (1 minute Half-life temperature 130.0 ° C), t-butylperoxybutyrate (1 minute half-life temperature 136.1 ° C), and the like. And bis (4-t-butylcyclohexyl) peroxydicarbonate, dilauroyl peroxide, and dibenzoyl peroxide excellent in crosslinking reaction efficiency are preferably used. In particular, bis (4-t-butylcyclohexyl) peroxydicarbonate is preferable in view of decomposition temperature. These can be used 1 type or 2 or more types. Moreover, you may use together with the above-mentioned isocyanate compound.

(Titanium coupling agent)

As a titanium coupling agent suitably used as a crosslinking agent, it does not specifically limit, For example, it does not specifically limit, For example, those described in Paragraph "0072" of Unexamined-Japanese-Patent No. 2014-085616, or those The formula modified suitably can be mentioned.

(Zirconium compound)

It does not specifically limit as a zirconium compound suitably used as a crosslinking agent, For example, those described in Paragraph "0073" of Unexamined-Japanese-Patent No. 2014-085616, or those which modified them suitably are mentioned.

(Aluminum Chelate Compound)

It does not specifically limit as aluminum chelate compound used suitably as a crosslinking agent, For example, those described in Paragraph "0037" of Unexamined-Japanese-Patent No. 2008-251089, or those modified suitably are mentioned.

(Thermal acid generator)

Examples of the thermal acid generator include hexafluoroantimonate sulfonium salts, and commercially available products include SI-60, SI-60L, SI-80, SI-80L, SI-100, and SI-100L (above). , Sanshin Kagaku Kogyo Co., Ltd., CI-2624 (above, Nihon Soda Co., Ltd.), etc. are mentioned. You may use a thermal acid generator individually or in combination of 2 or more types.

[Silane coupling agent]

The pressure-sensitive adhesive composition of the present invention may further contain a silane coupling agent. This is because when using a silicon film (film), adhesiveness with a silicon film improves by containing a silane coupling agent.

A silane coupling agent does not have a siloxane bond and shows that it has two or more different reactors in a molecule | numerator.

The silane coupling agent used for the adhesive composition of this invention is not specifically limited, For example, 3-glycidoxy propyl triethoxysilane, methyl trimethoxysilane, dimethyldimethoxysilane, and trimethylmethoxy Silane, n-propyltrimethoxysilane, ethyltrimethoxysilane, diethyldiethoxysilane, n-butyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltrimethoxysilane, phenyltri Methoxysilane, diphenyldimethoxysilane, cyclohexylmethyldimethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ Methacryloxypropylmethyl Imethoxysilane, (gamma) -methacryloxypropyl trimethoxysilane, (gamma) -methacryloxypropyl methyl diethoxysilane, (gamma) -methacryloxypropyl triethoxysilane, (gamma) -acryloxypropyl trimethoxysilane, N- β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrie Oxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimeth Oxysilane, (gamma) -mercaptopropylmethyldimethoxysilane, bis- (3- [triethoxysilyl] propyl) tetrasulfide, (gamma)-isocyanatepropyl triethoxysilane, etc. are mentioned. Moreover, the silane coupling agent which has functional groups, such as an epoxy group (glycidoxy group), an amino group, a mercapto group, and a (meth) acryloyl group, the silane coupling agent containing the functional group reactive with these functional groups, another coupling agent, polyiso The compound which has a hydrolyzable silyl group obtained by making cyanate etc. react with arbitrary functional groups at arbitrary ratios can also be used.

A commercial item may be used and the said silane coupling agent may use a synthetic product. As a commercial item of a silane coupling agent, it is KBM-303, KBM-403, KBE-402, KBE-403, KBE-502, KBE-503, KBM-5103, KBM-573, KBM-802, KBM-803, for example. And KBE-846, KBE-9007 (above, manufactured by Shin-Etsu Chemical Co., Ltd.).

The said silane coupling agents may be used individually or in combination of 2 or more types.

It is preferable that they are 0.0001 mass part or more and 10 mass parts or less with respect to 100 mass parts of main components (A), and, as for content when the adhesive composition of this invention contains a silane coupling agent, it is more preferable that they are 0.001 mass part or more and 5 mass parts or less. It is especially preferable that they are 0.01 mass part or more and 3 mass parts or less. If it is such a range, durability can be improved.

[solvent]

The solvent may be contained in the adhesive composition of this invention. Although it does not specifically limit as this solvent, Ester, such as ethyl acetate and n-butyl acetate; Aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; Alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; Organic solvents, such as ketones, such as methyl ethyl ketone and a methyl isobutyl ketone, are mentioned. These solvents can be used individually or in combination of 2 or more types.

In addition, as mentioned above, when the copolymer (a-3) is synthesize | combined by the bulk polymerization method using a photoinitiator, the obtained copolymer (a-3) is an unreacted (a-1) component, ( The form which contains at least one of a-2) component and (a ') component as a solvent can be set as what is called a polymer syrup. As a solvent used in this polymer syrup, (a-1) component, (a-2) component, and (a ') component which were illustrated above are mentioned. Therefore, the adhesive composition of this invention may contain at least one of (a-1) component, (a-2) component, and (a ') component as a solvent in a composition.

[Other Additives]

If necessary, the pressure-sensitive adhesive composition may contain, as necessary, known additives such as crosslinking accelerators, anti-aging agents, fillers, colorants (such as pigments and dyes), ultraviolet absorbers, antioxidants, chain transfer agents, plasticizers, softeners, surfactants, and antistatic agents. Other additive components) may be contained within a range that does not impair the effects of the present invention.

[Manufacturing Method of Adhesive Composition]

It does not specifically limit as a manufacturing method of the said adhesive composition. For example, when the curable compound in main component (A) is a form of said (1) which consists only of monomers, (a-1) component, (a-2) component, photoinitiator (B), and it adds as needed (a ') A component, a crosslinking agent, a silane coupling agent, a solvent, the method of mixing other additives, etc. are mentioned.

When the curable compound in the main component (A) is in the form of the above (2) consisting of a monomer and a polymer, a polymer syrup and photopolymerization comprising the component (a-1), the component (a-2) and the copolymer (a-3) The initiator (B) and the method (a ') added as needed, a crosslinking agent, a silane coupling agent, a solvent, a method of mixing other additives, etc. are mentioned.

The addition method of the photoinitiator (B) which concerns on this invention is not specifically limited. For example, a photoinitiator (B) comprises the (B) solution which prepared and melt | dissolved the photoinitiator (B) in at least one of (a-1) component and (a-2) component, and comprises a main component (A). You may adjust and add so that it may become desired content with respect to curable compound whole quantity. Or as shown in the Example, you may melt | dissolve and prepare a photoinitiator (B) in polymer syrup so that content may become desired content with respect to the curable compound whole quantity which comprises a main component (A).

[Adhesive film]

In one embodiment of the present invention, there is provided an adhesive film formed by curing the adhesive composition of the present invention. The pressure-sensitive adhesive film of the present invention is a cured layer of the pressure-sensitive adhesive composition of the present invention, and is formed by appropriately performing a curing treatment after applying (for example, applying) the pressure-sensitive adhesive composition (solution) of the present invention to a suitable substrate (support). Can be. When performing 2 or more types of hardening processes (drying, crosslinking, superposition | polymerization, etc.), these can be performed simultaneously or in multiple stages. In the adhesive composition of this invention, final copolymerization reaction is typically performed as the said hardening process (component (a-1), component (a-2), and / or copolymer (a-3), and a necessity. Thus, the added component (a ')) is subjected to the copolymerization reaction to form a complete polymer). For example, when an active energy ray curable adhesive composition is used, active energy ray irradiation is performed. If necessary, curing treatment such as crosslinking and drying may be performed. When it is necessary to dry with active energy ray hardenable adhesive composition, you may perform active energy ray hardening after drying.

In application of an adhesive composition, you may add a 1 or more types of solvent suitably.

As a base material of an adhesive film, the separator mentioned later can be used.

The coating method is not particularly limited, and various known methods can be used. For example, roll coat, baker applicator, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Methods, such as an extrusion coat method, are mentioned.

In the adhesive composition of this invention, since it contains a predetermined photoinitiator (B), after applying the adhesive composition of this invention directly on a to-be-adhered body, or to a predetermined to-be-coated body, such as a base material and a separator, or After coating on one surface on a support (base material), an adhesive film is obtained by irradiating an active energy ray. Usually, the illuminance is 1 mW / cm ² over 200 mW / cm ² or less UV light in the above wavelength 200nm 400nm or less, and irradiated to 200mJ / cm ² or more 10000mJ / cm ² or less at a cumulative amount of light is an adhesive film by photo-polymerization Obtained.

When the adhesive composition of this invention contains a solvent, it is preferable to dry a solvent. As a drying method of a solvent, the appropriate method can be employ | adopted according to the objective. Preferably, the method of heat-drying a coating film can be used. Heat-drying temperature becomes like this. Preferably it is 40 degreeC or more and 200 degrees C or less, More preferably, they are 50 degreeC or more and 180 degrees C or less, Especially preferably, they are 70 degreeC or more and 170 degrees C or less. By making heating temperature into the said range, the adhesive film which has the outstanding adhesive characteristic is obtained.

In addition, a drying time can be set suitably. Preferably it is for 5 seconds or more and 30 minutes or less, More preferably, it is for 5 seconds or more and 20 minutes or less, Especially preferably, it is for 10 seconds or more and 15 minutes or less. Heat drying can also be performed twice or more by changing conditions. For example, after drying at 40 degreeC or more and less than 100 degreeC for 0.1 minute or more and 10 minutes or less, you may further perform further drying process for 100 minutes or more and 200 degrees C or less for 1 minute or more and 20 minutes or less. Thereby, peeling, lifting, and crack generation by the volatilization of a solvent can be prevented.

The thickness (dry film thickness) of the pressure-sensitive adhesive film of the present invention is not particularly limited and may be appropriately set according to the use purpose. For example, in adhesive films, such as an optical film used for flexible displays, such as a curved display, it is preferable that they are 1 micrometer or more and 200 micrometers or less from a viewpoint of adhesiveness and bending resistance. In particular, when the pressure-sensitive adhesive film is formed using the pressure-sensitive adhesive composition of the present embodiment, even when the film thickness is significantly thinner than in the past, the same level as that of the thick film (usually about 200 μm) of flexible displays, such as curved displays, is provided. It is more preferable that the thickness (dry film thickness) of the adhesive film of this invention is 1 micrometer or more and 70 micrometers or less from the point which has the high adhesiveness of the adhesive film, and also the bending resistance superior to a thick film is obtained, and it is 5 micrometers or more and 70 micrometers or less. More preferred.

In addition, when the pressure-sensitive adhesive film according to the present invention is exposed, the pressure-sensitive adhesive film can be protected by a peeled sheet (separator) or the like until it is provided for practical use.

As a separator, for example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate (PET) film, polybutyl Plastic films, such as a lenterephthalate (PBT) film, a polyurethane film, and an ethylene-vinyl acetate copolymer film, are mentioned. In addition, suitable thin materials, such as porous materials, such as a paper, a cloth, and a nonwoven fabric, a net, a foam sheet, metal foil, and these laminates, are mentioned. However, in view of excellent surface smoothness, plastic films are suitably used.

The thickness of a separator is 5 micrometers or more and 200 micrometers or less normally, Preferably they are 5 micrometers or more and about 100 micrometers or less.

In addition, the separator can be subjected to antistatic treatment such as a release agent, antifouling treatment, coating type, kneading type, vapor deposition type, etc., with a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, silica powder, or the like, as necessary. . In particular, the peelability from the pressure-sensitive adhesive film can be further improved by appropriately performing a peeling treatment such as silicon treatment, long chain alkyl treatment, or fluorine treatment on the surface of the separator.

The adhesive film may have a glass transition temperature of less than -57.0 ° C. In the above range, even when the bending operation at the low temperature and high temperature of the pressure-sensitive adhesive film does not occur, peeling or lifting does not occur, and the folding resistance under both the high temperature and the low temperature is excellent.

The adhesive film is a 150-micrometer-thick PET film, a 50-micrometer-thick adhesive film, and a 100-micrometer thick film, respectively, by bonding a 150-micrometer-thick PET (polyethylene terephthalate) film and a 100-micron-thick PET film to both sides of a 50-micron-thick adhesive film. The three-layered specimen in which the PET film is bonded is placed in a bending tester with a 150-micrometer-thick PET film bent inward, bent at a radius of curvature of 3 mm, and bent at one cycle at a bending temperature of -20 ° C for 30 cycles per minute. When lifted between the adhesive film and the PET film, the first number of times that bubbles are generated may be 30,000 or more times, for example, 30,000 or more times 100,000 times or less. It can be used for flexible display in the above range. Lifting and bubble generation can be evaluated by a conventional method using a naked eye or an optical microscope.

When the pressure-sensitive adhesive film is evaluated at the bending temperature of 60 ° C. in the same manner as above, the pressure-sensitive adhesive film may be 30,000 times or more, for example, 30,000 times or more and 50,000 times or less, in which the number of times the bubbles are first generated. It can be used for flexible display in the above range.

As for the adhesive film, the storage elastic modulus G '(80) at 80 degreeC is preferable from a viewpoint of bending resistance at high temperature, 2.0x10 <^4> Pa or more. Preferably, the upper limit of the storage elastic modulus G'80 at 80 degreeC of an adhesive film is 4.0 * 10 <^4> Pa, More preferably, it is 3.5 * 10 <^4> Pa and 3.0 * 10 <^4> Pa. Within this range, flexural resistance at high temperatures may be good.

From the standpoint of bending resistance at low temperatures, the pressure-sensitive adhesive film preferably has a storage modulus of G '(-20) of -20 占 폚 of 3.5 × 10 ⁵ GPa or less, 2.6 × 10 ⁵ GPa or less, and 2.55 × 10 ⁵ GPa or less It is more preferable that it is 2.5 * 10 <^5> Pa or less. Preferably, the minimum of storage elastic modulus G '(-20) at -20 degreeC of an adhesive film is 0.5 * 10 <^5> Pa, More preferably, it is 0.7 * 10 <^5> Pa. Within this range, flexural resistance at low temperatures may be good.

The pressure-sensitive adhesive film has a ratio of storage modulus G '(-20) at -20 ° C to storage modulus G' (80) at 80 ° C of 1: 0.2 to 1: 1, preferably 1: 0.4 to 1: 1. Can be In the above range, the bending resistance is good at both low and high temperatures, so that the reliability of the flexible display may be good.

In the adhesive film, the shear deformation under 90 kPa shear stress is preferably 700% or more from the viewpoint of preventing cracking of the display element and peeling of the adhesive layer when the display is bent, and is 740% or more, 800% or more, 850% or more and 900. It is more preferable that it is% or more, even more preferably 1000% or more, preferably 2000% or less, preferably 1900% or less, 1800% or less, 1700% or less, 1600% or less, 1500% or less, 1400% or less, or 1300% or less. If it is this range, bending resistance is excellent.

The adhesive film preferably has an adhesive force of 300 g / 25 mm or more, more preferably 350 g / 25 mm or more, 550 g / 25 mm or more, still more preferably 750 g / 25 mm or more, and preferably 4,000 g / 25 mm or less. If it is such a range, the outstanding adhesive force with respect to an optical film etc. can be expressed.

It is preferable that the weight loss rate of the following Formula 3 is less than 1.0%, It is more preferable that it is 0.9% or less, It is more preferable that it is 0.8% or less, It is preferable that the adhesive film is 0.6% or less. Within this range, it is possible to effectively suppress the occurrence of an abnormal smell or outgas when the adhesive film is exposed to a high temperature (heating) environment in a manufacturing process such as a display.

<Equation 3>

% Reduction in weight = [(weight before heat treatment of adhesive film-weight after heat treatment of adhesive film) / weight before heat treatment] x100

(The above heat treatment is to leave the adhesive film at 150 ° C. for 1 hour.)

[Adhesive sheet]

In one embodiment of the present invention, an adhesive sheet containing an adhesive film formed by curing the adhesive composition of the present invention is provided. The pressure-sensitive adhesive sheet is a so-called base material pressure-sensitive adhesive sheet (one-sided or double-sided adhesive sheet) in which the pressure-sensitive adhesive film is prepared on one side or both sides of a sheet-shaped substrate (support) without fixing the adhesive film from the substrate. Alternatively, the adhesive film may be formed on a substrate having a peelability such as a peeling film (peel liner) (such as peeling or a resin sheet having a peeling treatment on the surface thereof), and the substrate supporting the adhesive film is removed at the time of sticking. It may be a so-called (double-sided) pressure-sensitive adhesive sheet without a form.

The concept of the adhesive sheet referred to herein may include those referred to as adhesive tapes, adhesive labels, adhesive films, and the like. Moreover, the said adhesive film is not limited to what was formed continuously, For example, the adhesive film formed in a regular or random pattern, such as a dot shape and stripe shape, may be sufficient.

As said base material (support), plastic materials, such as polyethylene terephthalate (PET) and a polyester film, porous materials, such as paper and a nonwoven fabric, metal foil, etc. are mentioned, for example.

As a constituent material of the said plastic base material, if it can be formed in a sheet form or a film form, it will not specifically limit, For example, polyethylene, a polypropylene, poly-1-butene, poly-4-methyl-1- pentene, Polyolefins such as ethylene propylene copolymer, ethylene-1-butene copolymer, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer and ethylene vinyl alcohol copolymer; Polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate and polybutylene terephthalate; Polyamides such as polyacrylate, polystyrene, nylon 6, nylon 6,6 and partially aromatic polyamide; Polyvinyl chloride, polyvinylidene chloride, polycarbonate, and the like.

The thickness of the substrate is not particularly limited, but is preferably 4 µm or more and 100 µm or less, more preferably 4 µm or more and 50 µm or less.

The plastic substrate may be subjected to release and antifouling treatments, acid treatments, alkali treatments, primer treatments, corona treatments, plasma treatments, ultraviolet treatments, etc., if necessary, with a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, silica powder, or the like. Antistatic treatment such as easy adhesion treatment, coating type, kneading type, and vapor deposition type may be performed.

Moreover, the separator illustrated above is mentioned as said peeling film (peeling liner).

[Usage]

The pressure-sensitive adhesive composition, pressure-sensitive adhesive film and pressure-sensitive adhesive sheet of the present invention described above can be applied to various applications, and can be used, for example, for optical members such as optical films. As such an optical film, it does not specifically limit, What is used for formation of image display apparatuses, such as a liquid crystal display device, is mentioned. For example, at least one of a polarizing plate or a retardation plate, and at least one of a conductive layer and a protective layer, a cover film, a transparent conductive film, a window film, a viewing angle magnifying film for improving the viewing angle of a liquid crystal monitor, and the like. And an optical compensation film, a brightness enhancing film for increasing the contrast of the display, and even those laminated thereon. That is, in one Embodiment of this invention, the optical member provided with the adhesive film which hardened the adhesive composition which concerns on this invention is provided.

The pressure-sensitive adhesive composition of the present invention may be used by directly applying on one side or both sides of the optical member to form an adhesive film, and is used by previously forming an adhesive film on the release film, and transferring this onto one side or both sides of the optical member. You may be. Since the adhesive composition of this invention has the outstanding durability, the lifting and peeling of the adhesive film by heat processing or a high humidity process can be prevented.

The adhesive composition, the adhesive film, and the adhesive sheet of this invention are used suitably for an image display apparatus. As an image display apparatus, a liquid crystal display apparatus, an organic electroluminescence display, a plasma display (PDP), a curved display, a flexible display, etc. are mentioned.

As described above, the present invention relates to an adhesive composition, an adhesive film, an adhesive sheet, and an image display device, wherein the adhesive force and bending resistance hardly occur when peeling or lifting occurs even when bending under high temperature and low temperature conditions. The adhesive composition excellent in the balance of can be provided. Moreover, the adhesive composition of this invention is used suitably for manufacture of the various films or sheets used for liquid crystal display elements, such as a flexible display, an electroluminescent element, etc., and can be compatible with these technical fields.

[ Example ]

The effect of this invention is demonstrated using the following example and a comparative example. However, the technical scope of the present invention is not limited only to the following examples. In addition, all the parts and% in each case are a mass reference | standard. Unless otherwise specified, all room temperature standing conditions are 23 degreeC (room temperature) and 55% RH.

<Viscosity>

The main component (A) put into the glass bottle was temperature-controlled at 25 degreeC, and it measured by the Brookfield viscometer.

Measurement of Weight Average Molecular Weight of Copolymer (a-3)

The weight average molecular weight of the copolymer (a-3) was measured by GPC (gel permeation chromatography).

Analysis equipment: manufactured by Tosoh Corporation, HLC-8120GPC

Column: Tosoh Corporation, G7000H _XL + GMH _XL + GMH _XL

ㆍ Column Size: Each 7.8mmφx30cm Total 90cm

Column temperature: 40 ° C

ㆍ flow rate: 0.8 ml / min

ㆍ injection volume: 100µl

Eluent: tetrahydrofuran

Detector: Differential Refractometer (RI)

ㆍ Standard sample: Polystyrene.

(Manufacture example 1)

<Preparation of main component (A-1)>

The main component (A-1) was prepared as shown below.

The reaction was performed in the reaction box provided in four flasks (FL20SBL by Sankyo Denki Co., Ltd., 315 nm or more and 400 nm or less) of UV lamps in the environment which shielded external ultraviolet rays.

81 parts by mass of 2-ethylhexyl acrylate (2EHA) (manufactured by Nihon Shokubai Co., Ltd.) and 4-hydroxybutyl acrylate (4HBA) in a reaction vessel equipped with a nitrogen gas introduction tube, a thermometer, and a stirring device. 15 parts by mass of Nippon Kasei Co., Ltd., 3 parts by mass of methoxy polyethylene glycol acrylate (AM-130G, product of Shin-Nakamura Kagakukyo Co., Ltd.), N-hydroxyethyl acrylamide (HEAA) (manufactured by KJ Chemical Co., Ltd.) 0.005 parts by mass of 2,2-dimethoxy-1,2-diphenylethan-1-one (Irgacure® 651; manufactured by BASF) as 1 part by mass and a polymerization initiator are dissolved (polymerization initiator). Was dissolved in a monomer solution), and then UV irradiation was performed at room temperature under a nitrogen atmosphere. Specifically, ultraviolet light (UV) (wavelength: 365 nm) having an illuminance of 2.5 mA / cm ² was irradiated using black light (FL20SBL, manufactured by Sangyo Denki Co., Ltd.) to initiate polymerization. After the start of the reaction (irradiation), the temperature of the reaction system was increased, but the irradiation of the black light was stopped when the increase in the reaction temperature from the start of the reaction (irradiation) reached 7 ° C, and air was introduced into the reaction vessel from the air pump. The reaction was forcibly stopped. That is, UV irradiation is performed until the temperature rise from the start reaches 7 degreeC, and the main component (A-) which is a polymer solution containing the copolymer (a-3-1) by which one part of the said monomer components superposed | polymerized by this. 1) (in the form of a so-called polymer syrup) were prepared.

The weight average molecular weight of the copolymer (a-3-1) in the main component (A-1) was 1,190,000 (in terms of GPC polystyrene) and had a polymerization rate of 10.0%. The viscosity of the main component (A-1) was 1400 mPa · s. In addition, the copolymer (a-3-1) in the main component (A-1) was 10.0 parts by mass. In addition, said "polymerization rate" is the value of the reaction rate computed making 100% the case where all the injection monomers became a polymer (it does it similarly hereafter).

(Manufacture example 2)

<Preparation of main component (A-2)>

The main component (A-2) was prepared as shown below.

The reaction was performed in the reaction box provided in four flasks (FL20SBL by Sankyo Denki Co., Ltd., 315 nm or more and 400 nm or less) of UV lamps in the environment which shielded external ultraviolet rays.

70 mass parts of 2-ethylhexyl acrylate (made by Nihon Shokubai Co., Ltd.), 4-hydroxybutyl acrylate (made by Nippon Kasei Co., Ltd.) 30 to the reaction container provided with the nitrogen gas inlet tube, the thermometer, and the stirring apparatus in the said box. 0.005 parts by mass of 2,2-dimethoxy-1,2-diphenylethan-1-one (Irgacure® 651; manufactured by BASF Corporation) as a mass part and a polymerization initiator were dissolved to form a polymerization initiator. After dissolving in a monomer solution), UV irradiation was performed at room temperature under a nitrogen atmosphere. In detail, in order to start superposition | polymerization, the ultraviolet-ray (UV) (wavelength: 365 nm) of illuminance 2.5 dl / cm <^2> was irradiated using black light (FL20SBL, product of Sankyo Denki Co., Ltd.). After the start of the reaction (irradiation), the temperature of the reaction system increased, but when the increase in the reaction temperature from the start of the reaction (irradiation) reached 7 ° C, irradiation of the black light was stopped, and air was introduced into the reaction vessel from the air pump. The reaction was forcibly stopped by doing so. That is, UV irradiation is performed until the temperature rise from the start time reaches 7 degreeC, and the main component (A) which is a polymer solution containing the copolymer (a-3-2) by which one part of the said monomer components superposed | polymerized by this. -2) (in the form of a so-called polymer syrup) were prepared.

The weight average molecular weight of the copolymer (a-3-2) in the main component (A-2) was 2.2 million (in terms of GPC polystyrene), and the polymerization rate was 9.5%. The viscosity of the main component (A-2) was 2500 mPa · s. In addition, the copolymer (a-3-2) in the main component (A-2) was 9.5 parts by mass.

Tg of the homopolymer shown in following Table 2 is the value calculated | required by the DSC method based on JISK7121 (1987). In addition, as long as the catalog value of each manufacturer is the value calculated | required by the said measuring method, you may apply the catalog value of each manufacturer.

[Evaluation 1]

<Measurement of glass transition temperature of main component>

The glass transition temperature (Tg) of each main component (or copolymer) is represented by the formula of the following FOX from the monomer units constituting the copolymers (a-3-1, a-3-2) of each main component and their ratios. It is a calculated value. As for each homopolymer Tg, 2-ethylhexyl acrylate is -64.5 degreeC, 4-hydroxybutyl acrylate is -37.2 degreeC, methoxy polyethyleneglycol acrylate AM-130G is -66.6 degreeC, N-hydroxyethyl acrylamide Was 91.7 ° C, Tg of the main component (A-1) was -59.9 ° C, and Tg of the main component (A-2) was -57.0 ° C.

The theoretical glass transition temperature obtained from the equation of FOX agrees well with the measured glass transition temperature determined by differential scanning calorimetry (DSC), dynamic viscoelasticity, and the like.

(Example 1)

(Preparation of Adhesive Composition)

Oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) as a photopolymerization initiator (B) based on 100 parts by mass of the main component (A-1) obtained in Production Example 1) 0.3 parts by mass of (Ezacure (registered trademark) One, product of DKSH Japan Co., Ltd .; number average molecular weight 424.57) was mixed, mixed and degassed to obtain a photopolymerizable pressure-sensitive adhesive composition.

(Formation of Adhesive Film)

Next, a baker-type applicator is placed on a PET film (trade name: MRF50, manufactured by Mitsubishi Kagaku Polyester Film Co., Ltd., thickness: 50 µm) to which the photopolymerizable pressure-sensitive adhesive composition (coating solution) is subjected to a release treatment by a silicone-based release agent as a release film. It applied so that it might become a coating thickness of 50 micrometers using, and the coating film was formed. The PET film (peel film) subjected to the release treatment with the same silicone mold release agent on the coating film is further placed on the coating film, and the peeling film is disposed above and below the coating film of the pressure-sensitive adhesive composition to be laminated (sealed). It was. Then, the pressure-sensitive adhesive was irradiated with ultraviolet light (wavelength: 365 nm) having an illuminance of 2.5 mW / cm ² for 10 minutes using a black light (FL20SBL, manufactured by Sangyo Denki Co., Ltd.) at normal temperature (accumulated light amount: 1500 mJ / cm ² ). The coating film of the composition was cured. This obtained the adhesive sheet in which the 50-micrometer-thick colorless transparent adhesive film was hold | maintained between two PET films.

(Example 2)

Oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) of Photopolymerization Initiator (B) (Ezacure (R) One, DKSH Japan) Oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propaneone) (Ezacure (registered trademark) KIP150; DKSH Japan Co., Ltd.) instead of number average molecular weight 424.57 Product, sold as 2-hydroxy-2-methyl [4- (1-methylvinyl) phenyl] propanol oligomer), was prepared in the same manner as in Example 1 to prepare an adhesive composition and an adhesive sheet.

(Example 3)

Oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) of Photopolymerization Initiator (B) (Ezacure (R) One, DKSH Japan) 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propane-1 instead of the number average molecular weight 424.57) A pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet were produced in the same manner as in Example 1, except that -ON (Irgacure (registered trademark) 127) and manufactured by BASF Japan Co., Ltd.) was used.

(Example 4)

In Example 1, the adhesive composition and the adhesive sheet were produced like Example 1 except having used 0.1 mass part instead of using 0.3 mass part of photoinitiators (B).

(Example 5)

In Example 1, the adhesive composition and the adhesive sheet were produced like Example 1 except having used 1.0 mass part instead of using 0.3 mass part of photoinitiators (B).

(Example 6)

In Example 1, 0.2 parts by mass of dipentaerythritol hexaacrylate (A-DPH, manufactured by Shin-Nakamura Kagaku Kogo Co., Ltd.) was further used as a crosslinking agent (C) with respect to 100 parts by mass of the main component (A-1). In the same manner as in Example 1, an adhesive composition and an adhesive sheet were produced.

(Example 7)

In Example 6, an adhesive composition and an adhesive sheet were produced in the same manner as in Example 6 except that 0.3 parts by mass was used instead of 0.2 parts by mass of the crosslinking agent (C).

(Comparative Example 1)

Oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) of Photopolymerization Initiator (B) (Ezacure (R) One, DKSH Japan) In the same manner as in Example 1, except that 1-hydroxycyclohexylphenyl ketone (IRGACURE® 184, manufactured by BASF Japan Co., Ltd.) was used instead of the number average molecular weight 424.57. The composition and the adhesive sheet were produced.

(Comparative Example 2)

Oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) of Photopolymerization Initiator (B) (Ezacure (R) One, DKSH Japan) 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) phenoxy] phenyl} -2-methylpropanone (Eza) instead of the number average molecular weight 424.57) A pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet were prepared in the same manner as in Example 1, except that Cure KIP160, manufactured by DKSH Japan, Inc .; number average molecular weight 342.39) was used.

(Comparative Example 3)

In Example 3, an adhesive composition and an adhesive sheet were produced in the same manner as in Example 3 except that the main component (A-2) was used instead of the main component (A-1).

<Measurement of storage modulus>

The pressure-sensitive adhesive sheets obtained in the examples and the comparative examples were cut out to a size of 1.0 mm × 1.0 mm, two PET films were peeled off, the pressure-sensitive adhesive film was taken out, and the laminate was processed to have a thickness of 3 mm. The pressure-sensitive adhesive film (cured pressure-sensitive adhesive composition) after lamination was attached to a dynamic viscoelasticity measuring device (Exstar DMS7100, manufactured by Hitachi High-Tech Science Co., Ltd.). In the shear mode, the frequency 1 Hz, and the temperature increase rate of 5 ° C./min, measurements were carried out in the temperature range of −30 ° C. to 100 ° C., and the storage modulus G ′ (-20) at −20 ° C. and the storage modulus G ′ at 80 ° C. (80) was measured. The results obtained are shown in Table 4 below.

<Measurement of Glass Transition Temperature after Curing of Adhesive Composition>

The glass transition temperature after hardening was measured using the adhesive composition produced by each Example and the comparative example. That is, the measurement was carried out by the DSC method according to JIS K7121 (1987), and these results are the same as those obtained by the measurement of the glass transition temperature (Tg) of the main component (copolymer). do. The obtained results are shown in Table 4 above.

[evaluation]

<Measurement of gel fraction>

The gel fraction of the adhesive composition produced by each Example and the comparative example was measured. The gel fraction was performed by the following method. That is, about 0.1 g of the adhesive composition was weighed, and the weight W ₁ (g) was measured. This was collected into a sample bottle, and about 30 g of ethyl acetate was added and left to stand for 24 hours. The contents of the sample bottle after a predetermined period of time were separated by filtration through a 200 mesh stainless steel wire mesh (weight of the film W ₂ (g)), and the total weight W ₃ (g) obtained by drying the wire mesh and the residue at 90 ° C. for 1 hour. Was measured. The gel fraction was computed by following formula (2) from these measured values. The results obtained are shown in Table 4 below.

<Measurement of adhesive force>

Two PET films were peeled off from the adhesive sheet obtained by each Example and the comparative example, and the adhesive film was taken out.

Two PET films having a thickness of 50 µm (trade name: MRF50, manufactured by Mitsubishi Kagaku Polyester Film Co., Ltd.) were prepared, and corona treatment was performed on the surface on which the peeling treatment of the PET film was not performed. The pressure-sensitive adhesive film was bonded to the corona-treated side using a laminator, cut into a width of 25 mm x length of 100 mm, and then autoclaved at 50 ° C. and 0.5 MPa for 15 minutes to completely adhere. Then, after 1 hour standing in 23 degreeC and 55% RH atmosphere, adhesive force was measured. The corona treatment was performed by passing a PET film twice through a corona irradiation section set to a speed of 1.6 m / min and a voltage of 9.5 kV using a 3DT corona treating system (manufactured by Poly DYNE).

Adhesive force is JIS Z0237 (2009) at a peel angle of 180 ° and a peel rate of 0.3 m / min using a tensile tester (Tenshiron Universal Testing Machine STA-1150, product of Orient Tech Co., Ltd.) at 23 ° C and 55% RH atmosphere. Based on the test method of the adhesive tape and the adhesive sheet, it calculated | required by measuring the adhesive force (g / 25mm) at the time of pulling out and peeling a PET film. The results obtained are shown in Table 4 below.

<Measurement of Shear Deformation>

On the 50-micrometer-thick PET film (brand name: MRF50, Mitsubishi Chemical Co., Ltd. product), the adhesive composition obtained by each Example and the comparative example was apply | coated using the baker applicator, and the coating film was obtained. The obtained coating film was irradiated with the ultraviolet-ray (wavelength: 360 nm) of illumination intensity 2.5k / cm <^2> for 10 minutes using black light (accumulated light quantity: 1500 mJ / cm <^2> ), and the coating film was hardened. This obtained the 50-micrometer-thick adhesive film.

Shear deformation of the pressure-sensitive adhesive film was evaluated at 25 ° C. using a TA.XT_Plus Texture Analyzer (manufactured by Stable Micro System).

Referring to FIG. 1, two end portions of a PET (polyethylene terephthalate) film (thickness: 75 μm) having a width x length (50 mm × 20 mm) by an adhesive film having a width × length × thickness (20 mm × 20 mm × 50 μm) of each other The adhesive was laminated in the order of PET film / adhesive film / PET film and a specimen was prepared in which the contact area between the PET film and the adhesive film became horizontal x vertical (20 mm × 20 mm). The jig was fixed to both ends of the PET film of the specimen. The contact area between the PET film and the jig was set to be horizontal x vertical (15 mm x 20 mm). At 25 ° C, one jig is fixed at 10 MPa and the other jig is 1000% of the initial thickness of the adhesive film (unit: μm, X _o ) at a speed of 300 mm / min (10 times the initial thickness of the adhesive film, X ₃ ) After pulling up to reach the length of 1000% of the thickness of the adhesive film and maintained for 10 seconds and then restored to the speed (300mm / min) at the same speed as the pulled pressure-sensitive adhesive film when a force of 0kPa is applied to the adhesive film This increased length is called X ₂ (unit: μm). Referring to Figure 2, the length of the pressure-sensitive adhesive film X-axis, the force applied to the pressure-sensitive adhesive film to obtain a graph. When the length of the pressure-sensitive adhesive film stretched when a force of 90 kPa is applied to the pressure-sensitive adhesive film is X ₁ (unit: μm), the shear strain is a value calculated by the following formula (1).

<Equation 1>

Shear strain = (X ₁ ) / (X ₀ ) x 100

The results obtained are shown in Table 4 below.

<Measurement of Folding Resistance (Bending Test)>

2 PET films were peeled off from the adhesive sheet obtained by each Example and the comparative example, the 50-micrometer-thick adhesive film was taken out, and a hand was carried out on a 150-micrometer-thick PET film (brand name: A4300, Toyobo Co., Ltd. product). After attaching the 50-micrometer-thick adhesive film using a lamination, the 100-micrometer-thick PET film (brand name: A4100, Toyobo Co., Ltd.) was piled up, and it autoclaved for 15 minutes on 50 degreeC and 0.5 MPa conditions, and completely. It adhered closely. This obtained the adhesive sheet which two PET films adhered by the adhesive film of thickness 50micrometer.

The obtained adhesive sheet was a bending film tester (brand name: a bending tester, the product made by Tester Sangyo Co., Ltd.), and as a test environment, a PET film with a thickness of 150 µm was placed under conditions of a low temperature environment of -20 ° C or a high temperature environment of 60 ° C. By applying a repeated distortion load of 3 mm radius of curvature (30 cycles per minute = 30 cycles per minute, the number of repetitions: 30,000 times), it was visually checked whether peeling, lifting, wrinkles, etc., of the adhesive film and PET film were occurring. The evaluation results are shown in Table 4 below. It is practical if an evaluation result is "(circle)".

(Evaluation standard)

(Circle): It shows that there was no peeling, lifting, a wrinkle, etc.

X: It shows that there existed peeling and lifting.

<Weight loss rate>

0.3 g of the adhesive film obtained in each Example and Comparative Example was dried in a warm air oven at 150 ° C. for 1 hour, and after being taken out, it was left to stand at room temperature for 1 minute, the weight was measured, and the weight loss ratio ( %) Was obtained. The results obtained are shown in Table 4 below.

<Equation 3>

% Reduction in weight = [(weight before heat treatment of adhesive film-weight after heat treatment of adhesive film) / weight before heat treatment] x100

(The above heat treatment is to leave the adhesive film at 150 ° C. for 1 hour.)

The detail of the photoinitiator (B) and crosslinking agent (C) of Table 3 is shown in following Table 5.

Ezacure One
(Esacure One) Oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone)
(Ezacure (registered trademark) One, product of DKSH Japan) Ezacure KIP-150 Oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone)
(Ezacure (registered trademark) KIP-150, product of DKSH Japan) Irg-127 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propane-1-one
(Irgacure (registered trademark) 184, product made by BASF Japan) Irg-184 1-hydroxycyclohexylphenyl ketone
(Irgacure (registered trademark) 184, product made by BASF Japan) Ezacure KIP-160 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) phenoxy] phenyl} -2-methylpropanone
(Ezacure (registered trademark) KIP160; product of DKSH Japan Corporation) A-DPH Dipentaerythritol hexaacrylate
(NK ester A-DPH, product of Shin-Nakamura Kagaku Kyogo Co., Ltd.)

As shown in Table 4, the pressure-sensitive adhesive composition and the pressure-sensitive adhesive film of the present invention, under the durability test conditions, even if the bending test under the two conditions of high temperature and low temperature for the bonded film does not occur peeling or lifting, It is excellent in folding resistance in two conditions at low temperature, and can also suppress the occurrence of an abnormal smell or outgas.

On the other hand, Comparative Example 1 and Comparative Example 2, which does not include the photopolymerization initiator of the present invention, the weight loss rate is more than 1.0% can not effectively suppress the outgas generation or poor bending durability at high temperatures. In addition, Comparative Example 3 outside the glass transition temperature of the present invention did not have good bending resistance at low temperatures.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (20)

As an adhesive composition,
It comprises a main component (A) and a photopolymerization initiator (B) consisting of a curable compound,
The main component (A),
(i) a mixture of a (meth) acrylic acid ester monomer (a-1) and a hydroxyl group-containing (meth) acrylic monomer (a-2), or
(ii) The structural unit derived from the said (meth) acrylic acid ester monomer (a-1), the said hydroxyl group containing (meth) acryl monomer (a-2), and the said (meth) acrylic acid ester monomer (a-1) It contains the mixture of (1) and the copolymer (a-3) containing the structural unit (2) derived from the said hydroxyl group containing (meth) acryl monomer (a-2),
The photoinitiator (B) is an oligomer of (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) and 2-hydroxy-1- {4- [4- At least one of (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propane-1-one,
In the said adhesive composition, the glass transition temperature after hardening is less than -57.0 degreeC,
The said adhesive composition is an adhesive composition whose shear deformation under 90 kPa shear stress after hardening is 700% or more.
The adhesive composition of Claim 1 whose content of the said photoinitiator (B) is 0.05 mass part or more and 1 mass part or less with respect to 100 mass parts of said main components (A).
The adhesive composition of Claim 1 or 2 whose storage elastic modulus in 80 degreeC after hardening is 2.0 * 10 <^4> Pa or more.
The adhesive composition of Claim 1 or 2 whose storage elastic modulus in -20 degreeC after hardening is 3.5x10 <^5> Pa or less.
delete The adhesive composition of Claim 1 or 2 whose gel fraction is 50% or more and 95% or less.
The said (meth) acrylic acid ester monomer (a-1) is a (meth) acrylic acid ester monomer (a-1-1) component which has an alkyl group,-(AO) _p- Q ( A is a (meth) acrylic acid ester monomer (a-1-2) component having a group represented by an alkylene group having 1 to 4 carbon atoms, an integer represented by 1 to 20 carbon atoms, and Q is an alkyl group having 1 to 12 carbon atoms. Pressure-sensitive adhesive composition comprising a mixture of.
The adhesive composition of Claim 1 or 2 in which the said hydroxyl group containing (meth) acryl monomer (a-2) contains the monomer whose glass transition temperature of a homopolymer is -20 degrees C or less.
The adhesive composition of Claim 7 in which the said hydroxyl group containing (meth) acryl monomer (a-2) further contains the hydroxyl group containing (meth) acryl monomer which has an amide group.
The said (meth) acrylic acid ester monomer (a-1) 75 mass% or more and 95 mass% or less and the said hydroxyl group containing of Claim 1 or 2 with respect to the total amount of the said main component (A). Adhesive composition containing 5 mass% or more and 25 mass% or less of acrylic monomer (a-2).
The adhesive film formed by hardening | curing the adhesive composition of Claim 1 or 2.
Glass transition temperature is less than -57.0 ℃,
150m thick PET (polyethylene terephthalate) film and 100m thick PET film are bonded to both sides of 50m thick adhesive film, 150m thick PET film, 50m thick adhesive film, 100m thick PET film When the bonded three-layered specimen was bent at a bending cycle of -30 ° C at 30 cycles per minute at a bending temperature of -20 ° C, the PET film having a thickness of 150 µm was bent inward, bent at 3 mm in a bending tester, and then bent. And the number of times the initial recovery of the bubbles between the PET film and 30,000 times, the adhesive film.
The method of claim 12, wherein the pressure-sensitive adhesive film is the initial recovery of the lifting and bubbles between the pressure-sensitive adhesive film and the PET film when bending at 30 cycles per minute at the bending temperature of 60 ℃ for the specimen is more than 30,000 times, Adhesive film.
The pressure-sensitive adhesive film according to claim 12, wherein the pressure-sensitive adhesive film has a storage modulus G '(80) of at least 80 x 10 ⁴ Pa.
The pressure-sensitive adhesive film of claim 12, wherein the pressure-sensitive adhesive film has a storage modulus G '(-20) of -20 ° C of 3.5 x 10 ⁵ Pa or less.
The pressure-sensitive adhesive film of claim 12, wherein the pressure-sensitive adhesive film has a ratio of storage elastic modulus G '(-20) at -20 ° C: storage elastic modulus G' (80) at 80 ° C from 1: 0.2 to 1: 1. .
The pressure-sensitive adhesive film of claim 12, wherein the pressure-sensitive adhesive film has a shear strain of at least 700% under 90 kPa shear stress.
The pressure-sensitive adhesive film of claim 12, wherein the pressure-sensitive adhesive film has a weight loss ratio of Equation 3 below 1.0%:
<Equation 3>
% Reduction in weight = [(weight before heat treatment of adhesive film-weight after heat treatment of adhesive film) / weight before heat treatment] × 100
(The heat treatment in the above is to leave the adhesive film at 150 ℃ 1 hour).
The method of claim 12, wherein the adhesive film,
A main component (A) consisting of the curable compound, including a photoinitiator (B),
The main component (A) is a mixture of a (meth) acrylic acid ester monomer (a-1) and a hydroxyl group-containing (meth) acrylic monomer (a-2); And a copolymer comprising a structural unit (1) derived from the (meth) acrylic acid ester monomer (a-1) and a structural unit (2) derived from the hydroxyl group-containing (meth) acrylic monomer (a-2). at least one of (a-3),
The photoinitiator (B) is an oligomer of (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) and 2-hydroxy-1- {4- [4- The adhesive film which is formed from the adhesive composition which is at least 1 sort (s) of (2-hydroxy-2-methyl- propionyl) -benzyl] phenyl} -2-methyl- propane- 1-one.
An image display device comprising the adhesive film of claim 12.

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