TWI534237B - Transparent adhesive tape, film panel with metal film, cover panel - touch panel module laminated body, cover panel - display panel module laminated body, touch panel module - display panel module laminated body, and image display Device - Google Patents

Description

Transparent adhesive tape, film laminate with metal film, cover panel-touch panel module laminate, cover panel-display panel module laminate, touch panel module-display panel module laminate, and image display Device

The present invention relates to a transparent adhesive tape which can inhibit the foaming generated by the interface or the like even if a polycarbonate plate or an acrylic plate is used as the adherend, and the adhesive body generates outgassing in a high temperature environment. The ridge is peeled off, and the deterioration of the metal film is also suppressed. Moreover, the present invention relates to a film laminate with a metal film manufactured using the transparent adhesive tape, a cover panel-touch panel module laminate, a cover panel-display panel module laminate, and a touch panel module. - Display panel module laminate and image display device.

The display panel is used in various fields, especially in mobile phones, personal digital assistants, etc., not only for image display devices but also for input devices. In such an input device, the touch panel is bonded to the cover panel of the surface, for example, via a highly transparent adhesive such as an acrylic adhesive or a transparent adhesive tape. Previously, the cover panel of the touch panel used a glass plate, and recently, in addition to the glass plate, the use of a safe and lightweight polycarbonate plate, acrylic plate, and the like has been increasing.

However, it is known that polycarbonate sheets and acrylic sheets are apt to absorb moisture, and moisture is vaporized under high temperature conditions to generate outgassing. Therefore, there is a problem in that the appearance of poor appearance due to outgassing at the interface between the polycarbonate sheet or the acrylic sheet and the adhesive layer under high temperature conditions causes poor appearance. In order to prevent the appearance defect caused by the peeling of the ridge, for example, the molecular weight of the acrylic polymer which is appropriately adjusted to form the adhesive layer is made, but it is difficult to obtain a charge by such a method. The adhesive layer that inhibits the detachment of the ridges.

Moreover, the adhesive layer of the adhesive or the transparent adhesive tape used for the bonding of the above touch panel directly contacts the metal film surface of the film with the metal thin film, and the metal thin film contains silver, copper, ITO, ZnO, etc. Metal or metal oxide. Therefore, for example, an adhesive or a transparent adhesive tape for such use is required to suppress detachment of the ridge and suppress the occurrence of a decrease in conductivity due to deterioration of the metal thin film.

Patent Document 1 discloses a transparent double-sided transparent adhesive tape or an adhesive sheet having a transparent double-sided transparent adhesive tape or adhesive sheet, a transparent adhesive layer formed on both sides of a transparent substrate, and formed on a transparent substrate. The transparent adhesive layer on at least one side is formed of an adhesive composition containing a specific acrylic polymer (a) and an oligomer (b). In Patent Document 1, the acrylic polymer (a) is an acrylic polymer having an alkyl group having a carbon number of 4 to 12 (meth)acrylic acid alkyl ester. It is a monomer main component, and contains 3 to 10 parts by weight of a carboxyl group-containing monomer as a monomer component with respect to 100 parts by weight of the total monomer component, and further has a weight average molecular weight of 500,000 to 900,000; (b) an oligomer having a glass transition temperature of 60 to 190 ° C and a cyclic structure in which a homopolymer is formed as a monomer main component and 100 weights relative to the total monomer component The mixture contains 3 to 10 parts by weight of a carboxyl group-containing monomer as a monomer component, and further has a weight average molecular weight of 3,000 to 6,000.

Patent Document 1 discloses that the transparent double-sided transparent adhesive tape or the adhesive sheet described in the same document has excellent detachment prevention property, and further has transparency and anti-warpage. The music is also excellent." However, the transparent double-sided transparent adhesive tape or the adhesive sheet described in Patent Document 1 contains a large amount of a carboxyl group-containing component in the composition, and if the transparent adhesive tape or the adhesive sheet is attached to the metal film surface, it is contained. The carboxyl group causes deterioration due to a decrease in the resistance value of the metal thin film. For example, when the transparent adhesive tape or the adhesive sheet is used for the bonding of the touch panel, there is a problem that the touch panel malfunctions.

Patent Document 1: Japanese Laid-Open Patent Publication No. 2005-255877

An object of the present invention is to provide a transparent adhesive tape which can inhibit the subsequent interface generation even when, for example, a polycarbonate plate or an acrylic plate is used as the adherend, and the adherend generates outgassing in a high temperature environment. Foaming or bulging peeling, while also inhibiting the deterioration of the metal film. Moreover, an object of the present invention is to provide a film laminate with a metal film manufactured by using the transparent adhesive tape, a cover panel-touch panel module laminate, a cover panel-display panel module laminate, and a touch panel module. Group-display panel module laminate, and image display device.

The present invention is a transparent adhesive tape having an adhesive layer composed of an adhesive composition containing a (meth) acrylate-based copolymer as a main component, and the dynamic viscoelastic spectrum of the above adhesive layer at a frequency of 10 Hz. The loss tangent has a maximum value in a temperature range of -20 to 20 ° C, and the shear storage elastic modulus at 200 ° C is 2.5 × 10 ⁴ Pa or more, and the gel fraction is 70% by weight or more.

The invention is described in detail below.

The adhesive layer of the transparent adhesive tape of the present invention moves at a frequency of 10 Hz The loss tangent (tan δ) of the state viscoelastic spectrum has a maximum value in the temperature range of -20 to 20 °C. By setting the maximum value of the loss tangent to be within this range, the adhesion to the adherend can be made high at the time of bonding, and the occurrence of bulging peeling in a high-temperature environment can be prevented. The maximum value of the loss tangent is preferably in a temperature range of -15 to 15 ° C, more preferably in a temperature range of -10 to 10 ° C.

It is generally believed that the ridge stripping produced by the interface between the adherend and the adhesive layer which produces an outgassing in a polycarbonate sheet or an acrylic sheet is caused by the outgassing from the adherend under high temperature conditions and Gas pressure causes bubble growth. Therefore, it is considered that the bubble growth on the interface with the polycarbonate sheet or the acrylic sheet can be inhibited by increasing the adhesion or adhesion of the adhesive layer to the polycarbonate sheet and the acrylic sheet.

The temperature at which the loss tangent is the maximum value can be obtained, for example, by using a dynamic viscoelasticity measuring device (for example, manufactured by IT Meter and Control Co., Ltd., DVA-200, etc.) at a frequency of 10 Hz and a temperature rising rate of 5 The shear storage elastic modulus (G') and the shear loss elastic modulus (G") at -50 to 200 °C were measured under the conditions of °C/min, and the horizontal axis was taken as the temperature and the vertical axis was taken as the loss tangent (tan δ). And make a chart.

The adhesive layer of the transparent adhesive tape of the present invention has a shear storage elastic modulus (G') at 200 ° C of 2.5 × 10 ⁴ Pa or more. By making the shear storage elastic modulus at 200 ° C 2.5 × 10 ⁴ Pa or more, the occurrence of ridge peeling can be prevented. The shear storage elastic modulus at 200 ° C is preferably 3.0 × 10 ⁴ Pa or more, more preferably 4.0 × 10 ⁴ Pa or more.

The inventors have found that the ridge peeling produced in a high temperature environment is related to the shear storage elastic modulus measured by the adhesive layer under high temperature conditions. That is, in the high-temperature environment, the peeling of the interface between the polycarbonate sheet, the acrylic sheet, and the like and the adhesive layer tends to be such that the shear storage elastic modulus of the adhesive layer at a frequency of 10 Hz and 200 ° C is measured. The larger the ridges are peeled off, and the smaller the shear storage elastic modulus is, the more the ridges are peeled off. As a result of intensive studies, the inventors have found that the occurrence of ridge peeling can be prevented by setting the elastic modulus of the adhesive at 200 ° C to 2.5 × 10 ⁴ Pa or more.

It is considered that the reason why the ridge is peeled off in a high temperature environment is that the adhesive layer cannot be deformed and peeled off by the pressure of the outgas generated by the adherend. It is considered that by increasing the shear storage elastic modulus of the adhesive layer at 200 ° C, the adhesive layer is hardly deformed even in a high temperature environment, so that the occurrence of ridge peeling can be prevented.

Further, the upper limit of the shear storage elastic modulus (G') of the adhesive layer at 200 ° C is not particularly limited, and a preferred upper limit is 4.0 × 10 ⁶ Pa. When the shear storage elastic modulus (G') at 200 ° C exceeds 4.0 × 10 ⁶ Pa, the adhesion to the adherend tends to be deteriorated, and the ridge peeling may occur.

The shear storage elastic modulus at 200 ° C can be, for example, a dynamic viscoelasticity measuring device (for example, DVA-200, manufactured by IT Meter and Control Co., Ltd.), and the measurement mode is set to a shear mode at a frequency of 10 Hz and a temperature increase rate of 5 ° C. The condition of /min was measured.

The adhesive layer of the transparent adhesive tape of the present invention has a gel fraction of 70% by weight or more. By setting the gel fraction of the above adhesive layer to 70% by weight or more, it is possible to suppress the pressure of the outgas generated from the adherend in a high-temperature environment. The adhesive layer is deformed and the growth of bubbles is suppressed. Further, it is possible to suppress the deterioration of the metal thin film by transferring the component which deteriorates the metal thin film to the interface of the metal thin film. A preferred lower limit of the gel fraction of the above adhesive layer is 75% by weight, and a more preferred lower limit is 80% by weight. Further, the upper limit of the gel fraction of the pressure-sensitive adhesive layer is not particularly limited and may be 100% by weight.

The above gel fraction can be measured, for example, by the following method.

First, the transparent adhesive tape of the present invention was cut into a certain size to prepare a test piece. The obtained test piece was immersed in ethyl acetate at 23 ° C for 24 hours, and then the test piece was taken out from the ethyl acetate through a 200 mesh stainless steel mesh, and dried at 110 ° C for 1 hour. Then, the weight of the test piece after drying was measured, and the gel fraction was calculated using the following formula.

Gel fraction (% by weight) = 100 × (W _{2 -} W ₀ ) / (W _{1 -} W ₀ )

In the formula, W ₀ represents the weight of the substrate, W ₁ represents the weight of the test piece before the immersion, and W ₂ represents the weight of the test piece after the immersion and drying. When the transparent adhesive tape does not have a substrate, W ₀ =0.

In the adhesive layer of the transparent adhesive tape of the present invention, it is preferred that the sol component has a weight-weight molecular weight satisfying the following formula (a), and the amount of the sol component having a molecular weight of 100,000 or less accounts for the entire sol component in the converted weight content. The following formula (b) is satisfied.

250000≧A≧2000×(100-B) ^1.5 (a)

C≦100-3×(100-B) (b)

In the formula, A represents a converted weight molecular weight of the sol component, B represents a gel fraction (% by weight) of the adhesive layer, and C represents a sol component having a molecular weight of 100,000 or less contained in the sol component, which is contained in the converted weight of the entire sol component. rate (weight%).

If the weight average molecular weight of the sol component of the above adhesive layer does not reach the value of the right side of the formula (a), the deformation of the adhesive layer is caused by the pressure of the outgas generated from the adherend in a high temperature environment, and cannot be suppressed. The growth of bubbles. When the weight average molecular weight of the sol component of the above adhesive layer exceeds the value on the left side of the formula (a) (250,000), the adhesion to the adherend may be deteriorated. A preferred upper limit of the weight average molecular weight of the sol component of the above adhesive layer is 230,000.

When the sol component having a molecular weight of 100,000 or less contained in the sol component of the adhesive layer exceeds the value of the right side of the formula (b), the adhesive layer is caused by the pressure of the outgas generated from the adherend in a high temperature environment. Deformation occurs and the growth of bubbles cannot be suppressed.

Therefore, in a high-temperature environment, it is preferable to satisfy at least any one of the formulas (a) and (b) in order to suppress the growth of the bubble caused by the deformation of the adhesive layer caused by the pressure of the outgas generated by the adherend. More preferably, it satisfies the formula (a) and the formula (b).

The converted weight molecular weight of the above sol component can be measured, for example, by the following method.

First, the transparent adhesive tape of the present invention was cut into a certain size to prepare a test piece. The obtained test piece was immersed in tetrahydrofuran at 23 ° C for 24 hours, and then the solution was separated by a filter. For the fractionated solution, for example, a "2690 Separations Model" manufactured by Waters Co., Ltd. is used as a column, and a weight average of the sol component in terms of polystyrene is measured by GPC (Gel Permeation Chromatography). Molecular weight, molecular weight distribution. Further, the weight average molecular weight in terms of the polystyrene was used as the converted weight molecular weight.

Hereinafter, the constituent elements of the transparent adhesive tape of the present invention having an adhesive layer which more satisfies the loss tangent of the dynamic viscoelastic spectrum at the above frequency of 10 Hz and the shear storage elasticity at 200 ° C are described in more detail. Modulus, gel fraction, and molecular weight of the sol component.

In the present specification, the term "(meth)acrylic acid" means acrylic acid or methacrylic acid.

The above adhesive composition has a (meth) acrylate copolymer as a main component.

In the present specification, the term "main component" means that the pressure-sensitive adhesive usually contains 50% by weight or more, preferably 60% by weight or more, based on the total amount of the (meth)acrylate copolymer, and more preferably Preferably, it is 70% by weight or more.

The (meth) acrylate-based copolymer preferably contains a structural unit derived from a (meth) acrylate monomer having a structure represented by the following formula (1), and is derived from the following formula (2) The constituent unit of the (meth) acrylate monomer of the structure shown. By using the above (meth) acrylate-based copolymer having constituent units derived from the (meth) acrylate monomers, the obtained adhesive layer can be subjected to shear storage elastic modulus and gel at 200 ° C. The rate is within the specified range.

In the formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 4 to 14 carbon atoms. The hydrogen atom of the R ² alkyl group may be substituted with a cycloalkyl group. The cycloalkyl group is not particularly limited, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group.

In the formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an alkyl group having 1 to 3 carbon atoms.

The (meth)acrylate copolymer contains a constituent unit derived from a (meth) acrylate monomer having a structure represented by the above formula (1), and the resulting adhesive layer can be at a frequency of 10 Hz. The loss tangent of the dynamic viscoelastic spectrum is within the specified range, and the foam resistance of the adhesive layer can be improved.

On the other hand, the (meth) acrylate-based copolymer contains a constituent unit derived from a (meth) acrylate monomer having a structure represented by the above formula (2), and the frequency can be made at 10 Hz. When the loss tangent of the dynamic viscoelastic spectrum is kept within the specified range, the shear storage elastic modulus at 200 ° C is adjusted to a prescribed range. The reason for this is considered to be that the molecular chain length of the main chain of the (meth) acrylate-based copolymer is increased, whereby the molecular chains are entangled with each other.

a (meth) acrylate monomer having the structure represented by the above formula (1) There is no particular limitation, and examples thereof include n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate (2-ethyl). Hexyl(meth)acrylate), n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethyloctyl (meth)acrylate, decyl (meth)acrylate, (meth)acrylic acid Isodecyl ester, decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, isotetradecyl (meth) acrylate, and the like. Among them, it is preferably selected from the group consisting of 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, and n-butyl (meth)acrylate. At least one (meth) acrylate monomer is more preferably n-butyl (meth) acrylate.

When the (meth) acrylate-based copolymer contains a constituent unit derived from a (meth) acrylate monomer having a structure represented by the above formula (1), it is derived from the structure represented by the above formula (1). The ratio of the constituent unit of the (meth) acrylate monomer is not particularly limited, and a preferred lower limit is 20% by weight, and a preferred upper limit is 95% by weight. The ratio of the constituent unit derived from the (meth) acrylate monomer having the structure represented by the above formula (1) is more preferably 30% by weight, more preferably 90% by weight, and the lower limit is preferably 35 wt%, the optimal upper limit is 85% by weight.

The (meth) acrylate monomer having the structure represented by the above formula (2) is not particularly limited, and is preferably selected from the group consisting of methyl (meth) acrylate, ethyl (meth) acrylate, and (meth) acrylate. At least one (meth) acrylate monomer in the group consisting of n-propyl ester and isopropyl (meth) acrylate is more preferably ethyl (meth) acrylate.

The above (meth) acrylate-based copolymer is derived from the above-mentioned pass In the case of a constituent unit of the (meth) acrylate monomer having a structure represented by the formula (2), the ratio of the constituent unit derived from the (meth) acrylate monomer having the structure represented by the above formula (2) is not particularly Preferably, the lower limit is preferably 1% by weight, and preferably the upper limit is 60% by weight. The ratio of the constituent unit derived from the (meth) acrylate monomer having the structure represented by the above formula (2) is preferably a lower limit of 2% by weight, more preferably an upper limit of 50% by weight, and further preferably a lower limit of 5 The weight %, further preferably the upper limit is 40% by weight, the optimum lower limit is 10% by weight, and the optimum upper limit is 35% by weight.

The (meth) acrylate-based copolymer preferably further contains a constituent component derived from a monomer having a bicyclic ring structure and one olefinic double bond.

The adhesion of the adhesive layer to a polycarbonate plate or an acrylic plate is obtained by the above (meth)acrylate copolymer containing a constituent derived from a monomer having a bicyclic ring structure and an olefinic double bond. Sharply improved. By increasing the adhesion in this manner, it is possible to further prevent the occurrence of ridge peeling in a high temperature environment.

The bicyclic ring structure is not particularly limited, and examples of the functional group having the above bicyclic ring structure include bicyclo[1.1.0]butyl, bicyclo[1.1.1]pentyl, bicyclo[2.1.0]pentyl, and Bicyclo[3.1.0]hexyl, bicyclo[2.1.1]hexyl, bicyclo[2.2.0]hexyl, bicyclo[2.2.1]heptyl, bicyclo[3.1.1]heptyl,bicyclo[3.2.0]heptyl Bicyclo[4.1.0]heptyl, bicyclo[2.2.2]octyl, bicyclo[3.2.1]octyl, bicyclo[3.3.0]octyl, bicyclo[4.1.1]octyl, bicyclo[4.2. 0] octyl, bicyclo [5.1.0] octyl, bicyclo [3.2.2] fluorenyl, bicyclo [3.3.1] fluorenyl, bicyclo [4.2.1] fluorenyl, bicyclo [4.3.0] fluorenyl, Bicyclo [5.1.1] fluorenyl, bicyclo [5.2.0] fluorenyl, bicyclo [6.1.0] fluorenyl, bicyclo [4.3.1] fluorenyl, and hydrogen having the same A functional group or the like of a structure in which one of the atoms is substituted by a chain alkyl group or a cyclic alkyl group. Furthermore, the above substitution may be one or plural. The bicyclic ring structure is preferably a descending anthracene ring or an isoindole ring, and particularly preferably an isoindole ring.

The olefinic double bond is not particularly limited, and examples of the functional group having the olefinic double bond include a (meth)acryl fluorenyl group, a vinyl group, and an allyl group. Among them, the olefinic double bond is preferably a double bond of a (meth) acryl fluorenyl group, and is preferably a double bond of an acryl fluorenyl group.

As the monomer having a bicyclic ring structure and one olefinic double bond, specifically, for example, isodecyl (meth)acrylate having an isodecyl group and a (meth)acryl fluorenyl group is preferred, and the most preferred one is Isodecyl acrylate having an isodecyl group and an acrylonitrile group.

When the (meth)acrylate copolymer contains a constituent unit derived from the monomer having a bicyclic ring structure and one olefinic double bond, it is derived from the above single ring having a bicyclic ring structure and one olefinic double bond. The ratio of the constituent units of the body is not particularly limited, and a preferred lower limit is 10% by weight, and a preferred upper limit is 60% by weight. When the constituent unit derived from the monomer having a bicyclic ring structure and one olefinic double bond is less than 10% by weight, the effect of improving the adhesion to the adherend may not be obtained, and if it exceeds 60% by weight, There is a case where the obtained adhesive layer has a loss tangent of the dynamic viscoelastic spectrum at a frequency of 10 Hz, and a shear storage elastic modulus of 200 ° C does not reach the prescribed range. A lower limit of the ratio of the constituent unit derived from the above monomer having a bicyclic ring structure and an olefinic double bond is 12% by weight, more preferably 50% by weight, and still more preferably 14% by weight, and further preferably The upper limit is preferably 45% by weight, the lower limit is preferably 15% by weight, and the upper limit is preferably 40% by weight.

The (meth) acrylate-based copolymer preferably further contains a constituent component derived from a monomer having a polyethylene oxide chain having a repeating number of ethylene oxide of 8 to 45 and one olefinic double bond. The (meth) acrylate-based copolymer contains a constituent component derived from a monomer having a polyethylene oxide chain having an ethylene oxide repeat number of 8 to 45 and an olefinic double bond. When the obtained adhesive layer is returned to room temperature after exposure to high temperature and high humidity, water can be slightly dispersed, and as a result, whitening can be suppressed. In particular, when a film having a metal thin film containing a metal such as silver, copper, ITO, ZnO, or a metal oxide is used as the adherend, the whitening of the acrylic adhesive is remarkable, but the content is derived from having an epoxy resin. The repeating number of ethane is a constituent component of a polyethylene oxide chain of 8 to 45 and a monomer of one olefinic double bond, and the transparent adhesive tape of the present invention contains a metal or metal oxide such as ITO. When the metal thin film is used as a adherend, it can also suppress whitening which occurs under high temperature and high humidity.

When the number of repetitions of ethylene oxide in the above polyethylene oxide chain is less than 8, the obtained adhesive layer cannot sufficiently suppress the whitening which occurs under high temperature and high humidity. When the number of repetitions of the above ethylene oxide exceeds 45, the obtained adhesive cannot sufficiently suppress the whitening which occurs under high temperature and high humidity. Further, when the number of repetitions of the ethylene oxide exceeds 45, the compatibility of the monomer having a polyethylene oxide chain with another monomer which is a main component is lowered, and the adhesion of the obtained adhesive layer is improved. decline.

The monomer having a polyethylene oxide chain having a repeating number of ethylene oxide of 8 to 45 and one olefinic double bond is not particularly limited, and the whitening effect at high temperature and high humidity can be further effectively suppressed. In other words, a monomer having a structure represented by the following formula (3) is preferred.

In the formula (3), R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents an alkyl group having 1 to 30 carbon atoms, and n represents an integer of 8 to 45.

Moreover, since the monomer having a polyethylene oxide chain having an ethylene oxide repeat number of 8 to 45 and one olefinic double bond suppresses the whitening effect under high temperature and high humidity, the effect is particularly high. In the above formula (3), R ⁵ is a hydrogen atom or a methyl group, R ⁶ is an alkyl group having a carbon number of 18, and n is a monomer of 30, or R ⁵ is a hydrogen atom or a methyl group in the formula (3). R ⁶ is an alkyl group having 1 carbon number, and n is 23. The above specific single system having a polyethylene oxide chain having a repeating number of ethylene oxide of 8 to 45 and one olefinic double bond can inhibit whitening by a small amount of addition, so that the above acrylic copolymer is not copolymerized. The glass transition temperature (Tg) of the object rises above the desired level, and thus does not adversely affect the reliability of the transparent adhesive tape of the present invention.

Among the above-mentioned monomers having a polyethylene oxide chain having a repeating number of ethylene oxide of 8 to 45, as a commercially available product, for example, Blemmer PME-1000 (repeating number of ethylene oxide = 23, terminal) Methyl, manufactured by Nippon Oil Co., Ltd., Blemmer PME-400 (number of repeats of ethylene oxide = 9, terminal methyl, manufactured by Nippon Oil Co., Ltd.), Blemmer PME-2000 (number of repeats of ethylene oxide = 45, end Methyl, manufactured by Nippon Oil Co., Ltd.), NK Ester AM-130G (ring Ethylene oxide repeat number = 13, terminal methyl group, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), Light Ester 041MA (ethylene oxide repeat number = 30, terminal methyl group, manufactured by Kyoeisha Chemical Co., Ltd.), Blemmer PSE- 1300 (repeating number of ethylene oxide = 30, terminal octadecyl, manufactured by Nippon Oil Co., Ltd.), Blemmer AE-400 (repeating number of ethylene oxide = 10, terminal hydroxyl group, manufactured by Nippon Oil Co., Ltd.), Blemmer ANE -1300 (repeating ethylene oxide = 30, terminal mercaptophenyl group, manufactured by Nippon Oil Co., Ltd.) and the like.

When the (meth) acrylate-based copolymer contains a constituent unit derived from the above-mentioned monomer having a polyethylene oxide chain having an ethylene oxide repeat number of 8 to 45 and one olefinic double bond, the source The ratio of the constituent unit of the monomer having a polyethylene oxide chain having an ethylene oxide repeating number of 8 to 45 and one olefinic double bond is not particularly limited, and a preferred lower limit is 0.5% by weight. The upper limit is preferably 10% by weight. If the constituent unit derived from the above-mentioned monomer having a polyethylene oxide chain having an ethylene oxide repeating number of 8 to 45 and one olefinic double bond is less than 0.5% by weight, whitening may occur. If it exceeds 10% by weight, there is a case where the obtained adhesive layer has a loss tangent of the dynamic viscoelastic spectrum at a frequency of 10 Hz, and a shear storage elastic modulus of 200 ° C does not reach a predetermined range. A lower limit of the ratio of the constituent units derived from the above-mentioned monomer having a polyethylene oxide chain having an ethylene oxide repeating number of from 8 to 45 and one olefinic double bond is 0.7% by weight, and more preferably, the upper limit is 8重量%, further preferably, the lower limit is 0.9% by weight, further preferably the upper limit is 6% by weight, the most preferred lower limit is 1% by weight, and the most preferred upper limit is 5% by weight.

The (meth) acrylate-based copolymer may further contain a constituent unit derived from a monomer having a carboxyl group and one olefinic double bond. By the above (meth) propylene The acid ester-based copolymer contains a constituent unit derived from a monomer having a carboxyl group and one olefinic double bond, and the intermolecular interaction is increased, and the cohesive force of the adhesive layer is improved.

The monomer having a carboxyl group and one olefinic double bond is not particularly limited, and examples thereof include (meth)acrylic acid, (meth)acryloylacetic acid (meth) acryloylacetic acid, and (meth)acrylic acid oxime. An unsaturated monocarboxylic acid such as propyl propionic acid, (meth) acrylonitrile butyric acid, (meth) acryl valeric acid or crotonic acid, maleic acid, fumaric acid, methyl cis-butane An unsaturated dicarboxylic acid such as citraconic acid, mesaconic acid or itaconic acid.

When the (meth) acrylate-based copolymer contains a constituent unit derived from the monomer having a carboxyl group and one olefinic double bond, the constituent unit derived from the monomer having a carboxyl group and one olefinic double bond The ratio is not particularly limited, and a preferred upper limit is 3% by weight. When the constituent unit derived from the monomer having a carboxyl group and one olefinic double bond exceeds 3% by weight, when a metal thin film containing a metal such as ITO or a metal oxide is used as the adherend, it is easy to The case where the metal film is deteriorated. A more preferable upper limit of the ratio of the constituent unit derived from the monomer having a carboxyl group and one olefinic double bond is 1.5% by weight, and further preferably, the upper limit is 0.5% by weight.

The (meth) acrylate-based copolymer may further contain a constituent unit derived from a monomer having a structure represented by the following formula (4). By including such a constituent derived from a monomer having a hydroxyl group, the adhesion of the obtained transparent adhesive tape to the glass sheet can be improved. It is generally believed that due to the hydroxyl groups in the adhesive layer of the transparent adhesive tape and the hydroxyl groups present in the surface of the glass plate Hydrogen bonds are formed between them, so the force is increased.

In the formula (4), R ⁷ represents a hydrogen atom or a methyl group, and R ⁸ represents an alkyl group having a hydroxyl group.

Examples of the monomer having a structure represented by the above formula (4) include 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2-hydroxy(meth)acrylate. Propyl ester, 6-hydroxyhexyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-(methyl)propenyloxyethyl 2-hydroxypropyl phthalate (2-( Meth)acryloyloxyethyl 2-hydroxypropyl phthalate), 2-(meth)acryloyloxyethyl acid phosphate, and the like. In addition, examples of the commercially available product having a monomer having a structure represented by the above formula (4) include, for example, PLACCEL FA2D (manufactured by Daicel Co., Ltd.), Blemmer AE90, Blemmer AE200, and Blemmer AE400 (manufactured by Nippon Oil Co., Ltd.).

When the (meth) acrylate-based copolymer contains a constituent unit derived from a monomer having a structure represented by the above formula (4), a constituent unit derived from a monomer having a structure represented by the above formula (4) The ratio is not particularly limited, and is preferably a (meth) acrylate-based copolymer having a hydroxyl value of from 10 to 150 mgKOH/g. If the (meth) acrylate copolymer has a hydroxyl value of less than 10 When it is more than 150 mgKOH/g, if it is more than 150 mgKOH/g, the resin may be generated by polymerization due to impurities contained in the monomer having the structure represented by the above formula (4). The case of gelation. The hydroxyl value of the (meth) acrylate-based copolymer is more preferably in the range of 15 to 100 mgKOH/g.

Further, the hydroxyl value of the (meth) acrylate-based copolymer can be calculated by the following formula.

Hydroxyl value of (meth)acrylate copolymer (mgKOH/g) =56110×n×W/M

M: molecular weight of hydroxyl-containing monomer (-)

n: number of hydroxyl groups in one molecule of a hydroxyl group-containing monomer

W: weight ratio of the hydroxyl group-containing monomer in the (meth) acrylate copolymer (wt%)

A preferred lower limit of the weight average molecular weight of the above (meth) acrylate-based copolymer is 600,000, and a preferred upper limit is 1.5 million. If the weight average molecular weight of the (meth) acrylate-based copolymer is less than 600,000, the obtained adhesive layer may have a high temperature elastic modulus, and the 200 ° C shear storage elastic modulus may not reach a predetermined range and reliability. The situation of decline. When the weight average molecular weight of the (meth)acrylate copolymer exceeds 1.5 million, the fluidity may be lowered and the adhesion to the adherend may be lowered. The lower limit of the weight average molecular weight of the above (meth) acrylate-based copolymer is 700,000, and the upper limit is more preferably 1.4 million, and the lower limit is preferably 800,000, and the upper limit is preferably 1.3 million.

Furthermore, the weight average molecule of the above (meth) acrylate copolymer The amount means the value measured by polystyrene conversion by gel permeation chromatography (GPC). Specifically, for example, the above-mentioned (meth) acrylate-based copolymer is diluted with tetrahydrofuran (THF, Tetrahydrofuran) by a filter to obtain a dilution obtained by using a filter, and the obtained filtrate is used for a column (for example, Waters Corporation). The GPC method of the manufactured product name "2690 Separations Model" or the like is measured, whereby the weight average molecular weight of the above (meth)acrylate copolymer can be determined.

The method for producing the (meth) acrylate-based copolymer is not particularly limited, and examples thereof include a method of radically polymerizing a mixed monomer containing the above monomers in the presence of a polymerization initiator.

The polymerization method is not particularly limited, and examples thereof include a conventionally known polymerization method such as solution polymerization, emulsion polymerization, suspension polymerization, and bulk polymerization. Among them, solution polymerization is preferred.

The solvent to be used in the solution polymerization is not particularly limited, and examples thereof include ethyl acetate, toluene, dimethyl hydrazine, ethanol, acetone, and diethyl ether.

The amount of the solvent to be used in the solution polymerization is not particularly limited, and a lower limit is preferably 25 parts by weight based on 100 parts by weight of the mixed monomer, and a preferred upper limit is 300 parts by weight. When the amount of the solvent is less than 25 parts by weight, the molecular weight distribution of the obtained (meth) acrylate-based copolymer may be broadened. The adhesive layer composed of the adhesive containing such a (meth) acrylate-based copolymer may have a decrease in adhesion and cohesive force to the adherend and a decrease in reliability. If the amount of the above solvent is more than 300 parts by weight, the present invention is used to prepare a viscous (meth) acrylate copolymer. When the adhesive is formed to form an adhesive layer, a step of removing the solvent may be required.

The polymerization initiator is not particularly limited, and examples thereof include a persulfate, an organic peroxide, and an azo compound. Among them, an organic peroxide or an azo compound is preferred in view of the influence on the metal thin film when a metal thin film containing a metal such as ITO or a metal oxide is used as the adherend.

The persulfate salt is not particularly limited, and examples thereof include potassium persulfate, sodium persulfate, and ammonium persulfate. The organic peroxide is not particularly limited, and examples thereof include 1,1-bis(trihexyl peroxide)-3,3,5-trimethylcyclohexane and third hexyl peroxypivalate ( T-hexyl peroxy pivalate), tert-butyl peroxypivalate, laurel peroxide, 2,5-dimethyl-2,5-bis(2-ethylhexyl)peroxide Oxidized 3-hexyl hexanoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxyisobutyrate, peroxy-3,5,5-trimethylhexanoic acid Tributyl ester, butyl laurate, etc. The azo compound is not particularly limited, and examples thereof include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), and 4,4'- Azobis(4-cyanovaleric acid), 2,2'-azobis(2-methylbutyronitrile), azobis cyclohexanecarbonitrile, and the like.

These polymerization initiators may be used singly or in combination of two or more.

The amount of the polymerization initiator to be added is not particularly limited, and a preferred lower limit of 100 parts by weight of the above mixed monomer is 0.02 parts by weight, and a preferred upper limit is 0.5 parts by weight. When the amount of the above polymerization initiator is less than 0.02 parts by weight, the polymerization reaction may be insufficient or the polymerization reaction may take a long time. If the amount of the above polymerization initiator is more than 0.5 parts by weight, there is The weight average molecular weight of the obtained (meth) acrylate type copolymer is too low or the molecular weight distribution is too wide. The adhesive layer composed of the adhesive containing such a (meth) acrylate-based copolymer may have a decrease in adhesion to the adherend and a decrease in the cohesive force, and the reliability may be lowered.

The above adhesive composition preferably contains a crosslinking agent. By containing the above crosslinking agent, a crosslinked structure can be formed in the above (meth)acrylate copolymer. Further, the gel fraction of the obtained adhesive can be adjusted to a predetermined range by appropriately adjusting the kind or amount of the above-mentioned crosslinking agent.

The crosslinking agent is not particularly limited, and examples thereof include an isocyanate crosslinking agent, an aziridine crosslinking agent, an epoxy crosslinking agent, and a metal chelate crosslinking agent. Among them, an isocyanate crosslinking agent and/or an epoxy crosslinking agent are preferred in terms of performance such as heat resistance and durability.

The isocyanate crosslinking agent is not particularly limited, and is preferably an aliphatic isocyanate crosslinking agent. Among the above-mentioned aliphatic isocyanate-based crosslinking agents, for example, Coronate HX (manufactured by NIPPON POLYURETHANE Co., Ltd.), MITEC NY260A (manufactured by Mitsubishi Chemical Corporation), and the like are mentioned.

The epoxy-based crosslinking agent is not particularly limited, and is preferably an aliphatic epoxy-based crosslinking agent. In the above-mentioned aliphatic epoxy-based crosslinking agent, for example, DENACOL EX212, DENACOL EX214 (all manufactured by Nagase Chemtech X), E-5C (manufactured by Zaken Chemical Co., Ltd.), and the like are available as other commercially available products. The crosslinking agent is, for example, E-AX (manufactured by Soken Chemical Co., Ltd.).

The amount of the above crosslinking agent is not particularly limited, and is relative to the above (meth) A preferred lower limit of 100 parts by weight of the acrylate-based copolymer is 0.01 parts by weight, and a preferred upper limit is 10 parts by weight. When the amount of the above-mentioned crosslinking agent is less than 0.01 part by weight, the crosslinking of the (meth)acrylate-based copolymer may be insufficient, and the cohesive force of the obtained pressure-sensitive adhesive layer may be lowered to deteriorate the workability. The lower limit of the above-mentioned crosslinking agent is preferably 0.1 part by weight, more preferably 3.0 part by weight.

The above adhesive composition preferably contains a rust inhibitor. By containing a rust inhibitor, even if the transparent adhesive tape of the present invention is used for the touch panel bonding, the adhesive layer directly contacts the metal foil film surface of the film with the metal film and the metal film contains metal or In the case of a metal oxide, deterioration of the metal thin film can be further prevented.

The rust inhibitor is not particularly limited, and examples thereof include benzotriazole, alkylbenzotriazole, dicyclohexyl ammonium nitrite, diisopropyl ammonium nitrite, amine salts, and lower grades. A conventionally known rust inhibitor such as a fatty acid and such a salt, Ethylenediaminetetraacetic acid, gluconic acid, nitrogen triacetic acid, diethylenetriaminepentaacetic acid, or sodium citrate. Among them, preferred are benzotriazole and alkylbenzotriazole.

The amount of the rust inhibitor to be added is not particularly limited, and a lower limit is preferably 0.01 parts by weight based on 100 parts by weight of the (meth) acrylate-based copolymer, and a preferred upper limit is 10 parts by weight. If the amount of the rust inhibitor is less than 0.01 parts by weight, the rust-proof hardening of the metal is insufficient. If the amount of the rust inhibitor is more than 10 parts by weight, there is adhesion to the adhesive layer obtained by the adherend. The situation is reduced and the reliability is degraded. The lower limit of the above rust inhibitor It is 0.05 parts by weight, and a more preferred upper limit is 5.0 parts by weight.

The above adhesive composition may further contain a tackifying resin.

The tackifier resin is not particularly limited, and examples thereof include a xylene resin, a phenol resin, a rosin resin, and a terpene resin. These tackifier resins may be used singly or in combination of two or more. Among them, a xylene resin is preferred, and an alkylphenol reactant of a xylene resin is more preferred.

Further, as the tackifying resin, a hydrogenated resin is preferably used, and the transparency of the obtained adhesive layer is improved by using such a hydrogenated resin.

The above adhesive composition preferably further contains a decane coupling agent. In general, when a metal thin film containing a metal such as ITO or a metal oxide is used as the adherend, if an acrylic adhesive is used, the resistance value due to deterioration of the metal thin film is lowered, but the adhesive composition is used. When a ruthenium coupling agent is contained, even when a metal film containing a metal such as ITO or a metal oxide is used as the adherend, the deterioration of the resistance due to deterioration of the metal thin film generated under high temperature and high humidity can be suppressed. Further, by containing the above decane coupling agent, the obtained adhesive layer improves the adhesion to the adherend.

The decane coupling agent is not particularly limited, and examples thereof include vinyl trimethoxy decane, vinyl triethoxy decane, γ-methacryloyloxypropyl trimethoxysilane, and γ. - γ-methacryloyloxypropyl methyldimethoxysilane, γ-glycidoxypropyl trimethoxysilane, γ-glycidoxymethyl Dimethoxydecane, γ-glycidoxymethyldiethoxydecane (γ-glycidoxypropyl) Diethoxymethylsilane), γ-epoxypropoxy triethoxy decane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ- Aminopropyltrimethoxydecane, γ-aminopropyltriethoxydecane, γ-aminopropyltrimethylmethoxydecane, N-(2-aminoethyl)3-aminopropyltriethoxy矽, N-(2-aminoethyl) 3-aminopropylmethyldimethoxydecane, γ-mercaptopropyl trimethoxysilane, γ-mercaptopropyltriethoxysilane , butyl butyl trimethoxy decane, γ-mercaptopropyl methyl dimethoxy decane, and the like. Among them, an epoxy group-containing decane coupling agent is preferred.

The amount of the decane coupling agent to be added is not particularly limited, and is preferably 0.01 parts by weight, preferably 5 parts by weight, based on 100 parts by weight of the (meth) acrylate copolymer. When the amount of the above-mentioned decane coupling agent is less than 0.01 part by weight, the adhesion to the adherend may be lowered to cause peeling or the effect of suppressing the decrease in the resistance value due to deterioration of the metal thin film may not be sufficiently obtained. When the amount is 5 parts by weight, the release property of the release paper or the release film may be lowered, and the release paper or the release film may not be peeled off or may be peeled off, but the surface of the adhesive layer may be rough. A more preferred lower limit of the amount of the above decane coupling agent is 0.05 parts by weight, and a more preferred upper limit is 3 parts by weight.

Further, the above-mentioned adhesive composition may further contain a conventionally known additive such as a filler or an anti-aging agent, as long as the effects of the present invention are not impaired.

Further, another aspect of the present invention is a transparent adhesive tape having an adhesive layer composed of an adhesive composition containing a (meth) acrylate copolymer, a crosslinking agent, a rust preventive, and a decane coupling agent. And the above (meth)acrylic acid The ester-based copolymer contains 20 to 95% by weight of a constituent unit derived from a (meth) acrylate monomer having a structure represented by the above formula (1), and is derived from a structure having the structure represented by the above formula (2). 1 to 60% by weight of the constituent unit of the acrylate monomer, and 10 to 60% by weight of the constituent unit derived from the monomer having a bicyclic ring structure and an olefinic double bond, derived from the above-mentioned ethylene oxide a repeating number of a polyethylene oxide chain of 8 to 45 and a monomer of one olefinic double bond of 0.5 to 10% by weight, and containing a monomer derived from the structure represented by the above formula (4) In the constituent unit, the (meth) acrylate copolymer derived from the monomer has a hydroxyl value of 10 to 150 mgKOH/g and a weight average molecular weight of 600,000 to 1,500,000.

The method for producing the above-mentioned adhesive composition is not particularly limited, and examples thereof include the above-mentioned (meth)acrylate-based copolymer and, if necessary, the above-mentioned crosslinking agent, the above-mentioned tackifying resin, and the above-described decane coupling agent. A method in which the above additives and the like are mixed and stirred.

The thickness of the above-mentioned adhesive layer of the transparent adhesive tape of the present invention is not particularly limited, and a preferred lower limit is 5 μm, and a preferred upper limit is 1 mm. When the thickness of the above-mentioned adhesive layer is less than 5 μm, the adhesion of the adhesive layer to the adherend is lowered and the reliability is lowered. When the thickness of the above-mentioned pressure-sensitive adhesive layer exceeds 1 mm, the operability of the adhesive component may be bleed out. The lower limit of the thickness of the above adhesive layer is preferably 10 μm, and the lower limit is preferably 20 μm, more preferably 500 μm, and further preferably 300 μm.

The transparent adhesive tape of the present invention may be an unsupported type having no substrate, or may be a support type in which an adhesive layer is formed on both sides of the substrate.

The substrate is not particularly limited as long as it has transparency, and examples thereof include acrylic acid, olefin, polycarbonate, vinyl chloride, ABS (acrylonitrile butadiene styrene), and polyethylene terephthalate. A sheet made of a transparent resin such as a diester (PET), nylon, an amine ester or a polyimide, having a mesh-like structure, an apertured sheet, or the like.

The thickness of the substrate is not particularly limited, and a preferred lower limit is 2 μm, and a preferred upper limit is 200 μm. If the thickness of the substrate is less than 2 μm, the resulting transparent adhesive tape may be insufficient in strength and may be damaged or become difficult to handle. When the thickness of the base material exceeds 200 μm, the stiffness of the base material is too strong, and the followability of the surface of the obtained transparent adhesive tape may be deteriorated. The lower limit of the above substrate thickness is preferably 5 μm, and more preferably the upper limit is 100 μm.

The method of producing the transparent adhesive tape of the present invention is not particularly limited. As a method of producing a non-supporting transparent adhesive tape, for example, a method of forming an adhesive layer by applying the above-described adhesive composition onto a release-treated surface of a release paper or a release film can be used. On the adhesive layer, the newly prepared release paper or release film is superposed on the release-treated surface in contact with the adhesive layer to obtain a laminate, and then the obtained laminate is pressurized by a rubber roller or the like.

Further, as a method of producing the transparent adhesive tape of the present invention, a method of freely mixing a monomer having the above-mentioned respective monomers which are raw materials of the (meth)acrylate-based copolymer can be used by bulk polymerization. The base polymerization is carried out until the above (meth) acrylate-based copolymer is produced to carry out banding.

In the above-mentioned bulk polymerization, photopolymerization is preferred in terms of easy removal of heat of polymerization and easy control of the reaction.

In particular, as a method of producing the transparent adhesive tape of the present invention, it is preferred to use a method of coating a monomer composition containing the above mixed monomer, a photopolymerization initiator, an optional additive, and the like without a solvent. After forming a monomer layer on a release surface of a transparent synthetic resin film which has been subjected to release treatment on one side, a release process of another transparent synthetic resin film which is subjected to release treatment on a side of the monomer layer is superposed on the monomer layer On the surface, the monomer layer is subjected to light irradiation such as ultraviolet irradiation through a synthetic resin film, whereby the mixed monomer is subjected to radical polymerization.

In the case where photopolymerization is carried out in the presence of a rust inhibitor such as benzotriazole, a (meth) acrylate-based copolymer having a high molecular weight may not be obtained due to polymerization inhibition. Therefore, when the polymerization is carried out in the presence of a rust inhibitor, it is preferred to use a method other than photopolymerization such as solution polymerization.

In addition, the transparent synthetic resin film is not particularly limited, and examples thereof include a polyethylene terephthalate film.

Further, in the case where the transparent adhesive tape of the present invention is produced by photopolymerization, it is preferred that the mixed monomer contains two or more polymerizable functional groups in terms of forming a crosslinked structure at the same time of polymerization. Polyfunctional (meth) acrylate. The polyfunctional (meth) acrylate is not particularly limited, and examples thereof include 1,6-hexanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, and polypropylene glycol. Di(meth)acrylate, hydrogenated polybutadiene di(meth)acrylate, trimethylolpropane triacrylate, pentaerythritol tri(meth)acrylate, neopentyl alcohol tetra(methyl) Acrylate, polyurethane II (A) Acrylate, polyester di(meth)acrylate, and the like. Among them, 1,6-hexanediol diacrylate, polypropylene glycol diacrylate, hydrogenated polybutadiene is preferred in terms of a small decrease in stress dispersibility of the obtained adhesive layer and excellent adhesion performance. Diacrylate, polyurethane diacrylate, polyester diacrylate.

In the case where the above-mentioned mixed monomer contains the above-mentioned polyfunctional (meth) acrylate, the compounding amount of the above polyfunctional (meth) acrylate is not particularly limited, and a preferred lower limit of the above mixed monomer is 0.02% by weight. A preferred upper limit is 5% by weight. When the amount of the above-mentioned polyfunctional (meth) acrylate is less than 0.02% by weight, the crosslinking of the (meth) acrylate-based copolymer is insufficient, and the cohesive force of the obtained adhesive layer is lowered to deteriorate the workability. . When the amount of the above-mentioned polyfunctional (meth) acrylate is more than 5% by weight, the adhesion of the obtained adhesive layer to the adherend and the initial adhesion are lowered, and the reliability is lowered.

A more preferred lower limit of the above-mentioned polyfunctional (meth) acrylate in the above mixed monomer is 0.05% by weight, and a more preferred upper limit is 3% by weight.

The photopolymerization initiator is not particularly limited, and examples thereof include 4-(2-hydroxyethoxy)phenyl (2-hydroxy-2-propyl) ketone (manufactured by Merck, trade name "Darocur 2959"). Ketone photopolymerization initiator, α-hydroxy-α,α'-dimethyl-acetophenone (manufactured by Merck, trade name "Darocur 1173"), methoxyacetophenone, 2,2-di Methoxy-2-phenylacetophenone (manufactured by Ciba-Geigy Co., Ltd., trade name "Irgacure 651"), 2-hydroxy-2-cyclohexylacetophenone (manufactured by Ciba-Geigy Co., Ltd., trade name "Irgacure" 184") acetophenone photopolymerization initiator, benzyl dimethyl A ketal-based photopolymerization initiator such as a ketal, a halogenated ketone, an acyl phosphinoxide, an acyl phosphonate or the like.

The amount of the photopolymerization initiator to be added is not particularly limited, and a preferred lower limit of 100 parts by weight of the above mixed monomer is 0.01 part by weight, and a preferred upper limit is 5 parts by weight. When the amount of the photopolymerization initiator is less than 0.01 part by weight, the polymerization of the above-mentioned mixed monomer may be incomplete, and the obtained adhesive layer may not have the required physical properties due to a decrease in cohesive force. When the amount of the photopolymerization initiator is more than 5 parts by weight, the amount of radical generated during light irradiation increases, and the number average molecular weight of the obtained acrylic copolymer decreases or the gel fraction of the adhesive layer decreases. It inhibits the whitening of the adhesive layer produced under high temperature and high humidity.

A more preferred lower limit of the amount of the photopolymerization initiator to be added to 100 parts by weight of the above mixed monomer is 0.03 part by weight, and a more preferred upper limit is 1 part by weight.

The lamp used for the light irradiation is not particularly limited, and examples thereof include a lamp having a light-emitting distribution at a wavelength of 400 nm or less.

Examples of the lamp having a light-emitting distribution at a wavelength of 400 nm or less include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excited mercury lamp, and a metal halide lamp. Wherein, the light in the active wavelength region of the photopolymerization initiator is efficiently emitted, and the light absorption of the components other than the photopolymerization initiator contained in the monomer layer is less, and the light sufficiently reaches the above It is preferred that the inside of the monomer layer is effective for polymerizing the above mixed monomer. Learn to light.

The light irradiation intensity at the time of the light irradiation is not particularly limited. However, since it is a factor that affects the polymerization degree of the obtained acrylic copolymer, it is appropriately adjusted in accordance with the polymerization degree of the target acrylic copolymer or the performance of the pressure-sensitive adhesive layer.

For example, when an acetophenone-based photopolymerization initiator is used as the photopolymerization initiator, the light irradiation intensity in the wavelength region effective for photolysis of the acetophenone-based photopolymerization initiator is preferably from 0.1 to 100. mW/cm ² . Further, the wavelength region effective for photolysis of the acetophenone-based polymerization initiator is different depending on the photopolymerization initiator, and is usually about 365 nm to 420 nm.

When the transparent adhesive tape of the present invention is used, even when an adherend such as a polycarbonate plate or an acrylic plate which generates an outgassing in a high-temperature environment is used as the adherend, the subsequent interface can be suppressed. Bubble or ridge peeling. Moreover, even when it adheres directly to the metal film surface of the film which attached the metal film, the deterioration of the metal film can be suppressed. Further, it is also possible to suppress whitening which occurs when returning to normal temperature from a high temperature environment.

The transparent adhesive tape of the present invention is preferably a laminate in which a polycarbonate sheet is bonded to a metal film surface of a film with a metal film, and a metal film surface of an acrylic sheet and a film with a metal film. The laminate obtained by laminating the laminated body or the metal film surface of the two films with the metal thin film adhered to each other in an environment of a temperature of 85 ° C and a relative humidity of 85% for 240 hours, and the diameter is generated. The number of bubbles above 10 μm is 0.

The transparent adhesive tape of the present invention is preferably attached to a metal film surface of a film with a metal film at a temperature of 85 ° C and a relative humidity of 85%. The resistance value of the metal film after being left for 240 hours in the environment was within ±10% as compared with that before the placement.

The transparent adhesive tape of the present invention is preferably a laminate in which a polycarbonate sheet is bonded to a metal film surface of a film having a metal film, and a metal film on which an acrylic plate and a film having a metal film are attached. The laminated body obtained by laminating the laminated body or the ITO surface of the film with the metal film attached thereto was placed in an environment of a temperature of 85 ° C and a relative humidity of 85% for 240 hours, and taken out, and taken out for 20 minutes. The haze value is within ±1% compared to before placement.

The use of the transparent adhesive tape of the present invention is not particularly limited. When manufacturing an image display device such as a mobile phone or a personal digital assistant, it can be preferably used for the cover panel and the touch panel module for protecting the surface, or The cover panel and the display panel module, or the touch panel module and the display panel module (refer to FIG. 1). Especially in the case where the above-mentioned cover panel is a polycarbonate plate or an acrylic plate, it is preferable.

Moreover, a cover panel-touch panel module laminated body formed by the transparent adhesive tape of the present invention and then covering the panel and the touch panel module, and the cover panel and the display panel module via the transparent adhesive tape of the present invention The cover panel-display panel module laminate body, the touch panel module-display panel module laminated body formed by the transparent adhesive tape of the present invention and the touch panel module and the display panel module are also One of the inventions.

The transparent adhesive tape of the present invention can also be preferably used for bonding two films with a metal film (refer to Fig. 1).

Further, a film-attached body with a metal film formed by laminating two films with a metal film via the transparent adhesive tape of the present invention is also the present invention. One.

Moreover, the ITO film laminate having the present invention, the cover panel-touch panel module laminate of the present invention, the cover panel-display panel module laminate of the present invention, or the touch panel module of the present invention-display The image display device of the panel module laminate is also one of the inventions.

According to the present invention, it is possible to provide a transparent adhesive tape which can suppress the occurrence of the subsequent interface even when, for example, a polycarbonate plate or an acrylic plate is used as the adherend, and the adhesive body generates outgassing in a high temperature environment. The bubble or ridge is peeled off, and the deterioration of the metal film is also suppressed. Moreover, a film laminated body with a metal film manufactured by using the transparent adhesive tape, a cover panel-touch panel module laminated body, a cover panel-display panel module laminated body, a touch panel module-display Panel module laminated body and image display device.

Hereinafter, the aspects of the present invention will be described in further detail by way of examples, but the present invention is not limited to the examples.

(Example 1)

(1) Manufacture of (meth) acrylate copolymer

30 parts by weight of ethyl acrylate, 44.8 parts by weight of n-butyl acrylate, 21 parts by weight of isodecyl acrylate, and Blemmer PME as a monomer having a polyethylene oxide chain were added to a reactor equipped with a thermometer, a stirrer, and a cooling tube. -1000 (repeating number of ethylene oxide = 23, terminal methyl group, manufactured by Nippon Oil Co., Ltd.) 3 parts by weight, 1 part by weight of acrylic acid, 0.2 parts by weight of 2-hydroxyethyl acrylate, and 100 parts by weight relative to the monomers 60 parts by weight of acetic acid The ethyl ester was purged with nitrogen for 30 minutes to carry out nitrogen substitution, and then the reactor was heated to 70 °C. After 30 minutes, 0.12 part by weight of the third hexylperoxypivalate as a polymerization initiator was diluted with 40 parts by weight of ethyl acetate with respect to 100 parts by weight of the monomer, and polymerization initiation was obtained over 5 hours. The solution was dropped into the above reactor. Thereafter, the reaction was allowed to proceed for 8 hours from the addition of the polymerization initiator at 70 ° C to obtain a (meth) acrylate copolymer solution having a solid content of 50%.

For the obtained (meth) acrylate-based copolymer, a thermal decomposition apparatus (Double-Shot Pyrolyzer, manufactured by Frontier Lab, Inc.), and a GC-MS (gas chromatography mass spectrometry) apparatus (manufactured by JEOL Ltd., Q-1000GC) were used. , FT-IR (Fourier Transform Infrared Spectrometer) (manufactured by Thermo Fisher Scientific, NICOLET 6700) and NMR (Nuclear Magnetic Resonance) (manufactured by JEOL Ltd., JNM-ECA400), and the constituent units derived from the respective monomers constituting the acrylic copolymer were measured. The proportion (% by weight). The ratio (% by weight) of the constituent units obtained is shown in Table 1.

In addition, the "2690 Separations Model" manufactured by Waters Co., Ltd. was used as a column for the obtained (meth)acrylate copolymer, and the weight average molecular weight in terms of polystyrene was measured by a GPC method. The weight average molecular weight obtained is shown in Table 1.

Further, the hydroxyl value of the (meth) acrylate-based copolymer obtained by the above method is shown in Table 1.

(2) Manufacture of transparent adhesive tape

In the obtained (meth) acrylate copolymer solution, 100 parts by weight of the solid content component of the (meth) acrylate copolymer is used in a solid form KBTEC-403 (Shin-Etsu) which is a decane coupling agent is added in an amount of 0.5 parts by weight in terms of solid content, and is added as a crosslinking agent in the amount of 3 parts by weight. The chemical industry company), stirring, to prepare an adhesive composition.

The obtained adhesive composition is coated on a release treatment surface of a release polyethylene terephthalate film, and dried at 100 ° C for 10 minutes to remove ethyl acetate in the adhesive composition solution to form The adhesive layer having a thickness of 50 μm and 100 μm is further adhered to the obtained adhesive layer, and the newly prepared release polyethylene terephthalate film is superposed on the release-treated surface to contact the adhesive layer to obtain a laminate. . The laminated body obtained by pressurizing the laminated body was obtained by a rubber roller, thereby obtaining a transparent adhesive tape (thickness of 50 μm and 100 μm) to which a release-type polyethylene terephthalate film was attached.

(3) Maximum temperature of loss tangent and determination of shear storage elastic modulus at 200 °C

A transparent adhesive tape having a thickness of 1 mm was obtained by overlapping the obtained transparent adhesive tapes having a thickness of 100 μm. The shear adhesive elastic modulus of the obtained transparent adhesive tape at 200 ° C was measured by a dynamic viscoelasticity measuring device (manufactured by IT Meter and Control, DVA-200) at a frequency of 10 Hz and a heating rate of 5 ° C/min. '). Further, a dynamic viscoelasticity measuring apparatus (DVA-200, manufactured by IT Meter and Control Co., Ltd.) was used, and the measurement mode was set to a shear mode, and the temperature was measured at a frequency of 10 Hz and a temperature elevation rate of 5 ° C/min. °C shear storage elastic modulus (G') and shear loss elastic modulus (G"), and the horizontal axis as the temperature, the vertical axis as the loss tangent (tan Let δ) make a graph and find the temperature at which the loss tangent is the maximum value.

(4) Determination of gel fraction of adhesive layer

A transparent adhesive tape having a thickness of 100 μm was cut into a rectangular shape of 50 mm × 25 mm to prepare a test piece, and the weight W _{1 of the} produced test piece was measured. After the test piece was immersed in ethyl acetate at 23 ° C for 24 hours, the test piece was taken out from the ethyl acetate using a 200 mesh stainless steel sieve, and dried at 110 ° C for 1 hour. The weight W ₂ of the test piece after drying was measured, and the gel fraction was calculated by the following formula.

Gel fraction (% by weight) = 100 × (W _{2 -} W ₀ ) / (W _{1 -} W ₀ )

In the formula, W ₀ represents the weight of the substrate, W ₁ represents the weight of the test piece before the immersion, and W ₂ represents the weight of the test piece after the immersion and drying. In the case where the transparent adhesive tape does not have a substrate, W ₀ =0.

(5) Determination of molecular weight of sol component

A transparent adhesive tape having a thickness of 100 μm was cut into a rectangular shape of 50 mm × 50 mm to prepare a test piece, which was immersed in tetrahydrofuran at 23 ° C for 24 hours. Thereafter, the solution was separated by a filter, and the "2690 Separations Model" manufactured by Waters Co., Ltd. was used as a column, and the converted weight molecular weight and molecular weight distribution of the sol component in terms of polystyrene were measured by a GPC method.

In the table, when the weight average molecular weight of the sol component satisfies the following formula (a) and the ratio of the component having a molecular weight of 100,000 or less satisfies the following formula (b), it is referred to as "○", and when only one of the formulas is satisfied, "△", when both types are not satisfied, it is recorded as "X".

250000≧A≧2000×(100-B) ^1.5 (a)

C≦100-3×(100-B) (b)

In the formula, A represents a converted weight molecular weight of the sol component, B represents a gel fraction (% by weight) of the adhesive layer, and C represents a sol component having a molecular weight of 100,000 or less contained in the sol component, which is contained in the converted weight of the entire sol component. Rate (% by weight).

(Examples 2 to 29, Comparative Examples 1 to 4)

The same procedure as in Example 1 was carried out except that the monomer type and ratio of the (meth)acrylate copolymer, the decane coupling dose, the type and amount of the crosslinking agent, and the like were set as shown in Tables 1 to 4. (Meth) acrylate copolymer and transparent adhesive tape. Further, the maximum loss tangent temperature, the shear storage elastic modulus at 200 ° C, the gel fraction, and the molecular weight of the sol component were measured in the same manner as in Example 1.

(Evaluation)

The following evaluations were performed on the transparent adhesive tape and the film laminate obtained in the examples and the comparative examples. The results are shown in Tables 1 to 4.

(1) Evaluation of whitening (measurement of haze value)

The obtained transparent adhesive tape having a thickness of 100 μm was cut into a planar shape of 40 mm × 60 mm. The release polyethylene terephthalate film on the side of the cut transparent adhesive tape was peeled off, and the exposed surface of the transparent adhesive tape was attached to a transparent polyethylene terephthalate film having a thickness of 75 μm. Further, the release polyethylene terephthalate film on the other side of the transparent adhesive tape was peeled off, and the surface of the transparent adhesive tape exposed was attached to a glass slide (trade name "S-1214", manufactured by MATSUNAMI Co., Ltd.). A test piece having a layer structure of an adhesive layer/slide was prepared. The test piece was placed at a temperature of 85 ° C and a relative humidity (RH) of 85%. In a high humidity environment. The haze value (%) of the test piece before the start of the placement and after 240 hours of the placement was measured using a fog meter (automatic fog meter "TC-HIIIDPK", manufactured by Tokyo Denshoku Co., Ltd.), and the haze was calculated by the following formula. value.

△ haze value (%) = {haze value after 240 hours of placement (%)} - {haze value (%) before placement starts}

(2) Whether there is whitening when attached to the ITO film

The obtained transparent adhesive tape having a thickness of 100 μm was cut into a planar shape of 40 mm × 60 mm. The release polyethylene terephthalate film on the side of the cut transparent adhesive tape was peeled off, and the exposed surface of the transparent adhesive tape was attached to a transparent polyethylene terephthalate film having a thickness of 25 μm. Further, the release polyethylene terephthalate film on the other side of the transparent adhesive tape was peeled off, and the exposed surface of the transparent adhesive tape was attached to a film of 0.10 mm thick with an ITO film (amorphous ITO film, tail cell) A test piece having a layer structure of an adhesive layer/ITO film was produced on the ITO surface of an industrial company.

The test piece was placed in a high temperature and high humidity environment of 85 ° C and 85% RH. The haze value (%) of the test piece before the start of the placement and after the lapse of 240 hours was measured using a fog meter (automatic fog meter "TC-HIIIDPK", manufactured by Tokyo Denshoku Co., Ltd.), and the Δ haze was calculated by the above formula. value. When the value of Δ haze is less than 1, it is evaluated as “○”, and when the value of Δ haze is 1 or more and is less than 3, it is evaluated as “△”, and when the value of Δ haze is 3 or more, it is evaluated as “×”. "."

(3) Resistance evaluation between ITO films

The obtained transparent adhesive tape having a thickness of 100 μm was cut into a planar shape of 40 mm × 60 mm. Further cut 2 angles in a size of 10 mm × 10 mm And cut into a convex strip shape. The release polyethylene terephthalate film on the side of the cut transparent adhesive tape was peeled off, and the exposed surface of the transparent adhesive tape was attached to a transparent polyethylene terephthalate film having a thickness of 25 μm. Further, the release polyethylene terephthalate film on the other side of the transparent adhesive tape was peeled off, and the exposed surface of the transparent adhesive tape was attached to an ITO film having a thickness of 0.18 mm having a planar shape of 40 mm × 60 mm ( On the ITO surface of the amorphous ITO film, manufactured by Oike Industrial Co., Ltd., a conductive film layer of a transparent adhesive tape and polyethylene terephthalate is sequentially laminated on the ITO surface with the ITO film. body.

The initial resistance value of the obtained conductive film laminate was measured. Further, the conductive film laminate was allowed to stand in a high-temperature and high-humidity environment at 85 ° C and a relative humidity of 85% RH for 240 hours, and the resistance value of the conductive film laminate after standing was measured. In addition, the resistance value is measured in such a manner that the portion of the ITO film on which the ITO film is attached is not attached with a transparent adhesive tape to expose the surface of the ITO film, so that the transparent adhesive tape covers the form between the terminal and the terminal to contact the 2-terminal resistor. The terminal of the value measuring device is used to measure the resistance value. The deterioration level of the ITO film was evaluated using the rate of change of the resistance value calculated by the following formula.

Resistance change rate (%) = (R _{1 -} R ₀ ) / R ₀ × 100

In the formula, R ₀ represents an initial resistance value, and R ₁ represents a resistance value after being left in a high-temperature and high-humidity environment for 240 hours.

Further, the rate of change in the resistance value is preferably 20% or less, more preferably 15% or less. If the rate of change of the resistance value exceeds 20%, there is a case where an erroneous electric signal is input to the identification portion of the touch panel having the ITO film and an error is caused in response.

(4) Bubble generation state (flame resistance test)

The obtained transparent adhesive tapes having a thickness of 100 μm and 50 μm were cut into a flat shape of 45 mm × 60 mm. The release-type polyethylene terephthalate film on the side of the transparent adhesive tape is peeled off, and the exposed surface of the transparent adhesive tape is attached to the touch panel module having a thickness of 0.18 mm. Further, the release polyethylene terephthalate film on the other side of the transparent adhesive tape was peeled off, and the exposed surface of the transparent adhesive tape was bonded to a polycarbonate plate (PC plate) having a flat shape of 1 mm in thickness. Thereby, a module laminated body in which a transparent adhesive tape and a touch panel module are sequentially laminated on a polycarbonate plate (PC board) is obtained.

Thereafter, the obtained module laminate was treated with an autoclave at 23 ° C and 0.5 MPa for 15 minutes, and then allowed to stand at a temperature of 85 ° C and 85% RH or at a temperature of 60 ° C and 90% RH. After 240 hours, the cover panel-touch panel module laminate was obtained. The state of bubble generation at the interface of the resulting cover panel-touch panel module laminate was visually observed. When the bubble of 0.01 mm or more is not observed at all, it is set to "5 points", and when one cover of the cover panel-touch panel module is observed, one or two bubbles of 0.01 mm or more are observed. "4 points", when each cover panel-touch panel module laminate is observed, 3 to 5 bubbles of 0.01 mm or larger are set as "3 points", when each cover panel-touch panel module In the grouped layer, 6 to 9 bubbles of 0.01 mm or larger were observed as "2 points", and 10 or more bubbles of 0.01 mm or more were observed in each of the cover panel-touch panel module laminates. In the case of "1 minute", the bubble generation state is evaluated.

(Embodiment 30)

(1) Manufacture of (meth) acrylate copolymer

56.5 parts by weight of n-butyl acrylate, 10 parts by weight of 2-ethylhexyl acrylate, and 30 parts by weight of isodecyl acrylate were added to a reactor equipped with a thermometer, a stirrer, and a cooling tube as a single polyethylene oxide chain. Blemmer PSE-1300 (manufactured by Nippon Oil Co., Ltd.) 1.5 parts by weight, acrylic acid 1 1 part by weight, 1 part by weight of 4-hydroxybutyl acrylate, and 100 parts by weight of ethyl acetate based on 100 parts by weight of the monomers, and after nitrogen substitution by blowing nitrogen for 30 minutes, the reactor was heated to 60 ° C. . 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was diluted with 1 part by weight of ethyl acetate with respect to 100 parts by weight of the monomer. After 30 minutes, the obtained polymerization initiator solution was added to the above reactor at 60 ° C, and the reaction was allowed to proceed for 6 hours from the addition of the polymerization initiator to obtain a (meth) acrylate copolymer having a solid content of 50%. Solution.

(2) Manufacture of transparent adhesive tape

In the obtained (meth) acrylate-based copolymer solution, a decane coupling agent, a rust inhibitor, a curing agent, or the like was added in the amount shown in Table 5, and adhesion was obtained in the same manner as in Example 1. Composition and transparent adhesive tape. Further, in the same manner as in Example 1, the maximum loss tangent temperature, the storage elastic modulus at 200 ° C, the gel fraction, and the molecular weight of the sol component were measured.

(Examples 31 to 34, Comparative Examples 5 and 6)

The same procedure as in Example 30 except that the monomer species and ratio of the (meth)acrylate copolymer, the production method, the decane coupling dose, the type and amount of the curing agent were set as described in Table 5, A (meth) acrylate copolymer, an adhesive composition, and a transparent adhesive tape were obtained. Further, in the same manner as in Example 1, the maximum loss tangent temperature, the storage elastic modulus at 200 ° C, the gel fraction, and the molecular weight of the sol component were measured.

(Comparative Example 7)

56.5 parts by weight of n-butyl acrylate, 2-ethylhexyl acrylate 10 Parts by weight, 30 parts by weight of isodecyl acrylate, 1.5 parts by weight of Blemmer PSE-1300 (manufactured by Nippon Oil Co., Ltd.) as a monomer having a polyethylene oxide chain, 1 part by weight of acrylic acid, and 1 part by weight of 4-hydroxybutyl acrylate And 2,2-dimethoxy-2-phenylacetophenone as a photopolymerization initiator, based on 100 parts by weight of the monomer, (manufactured by Ciba-Geigy Co., Ltd., trade name) "Irgacure 651") was sufficiently stirred in a glass reaction vessel, and nitrogen gas was blown in for 30 minutes to carry out nitrogen substitution, and then irradiated with a low pressure mercury lamp for several minutes to obtain a viscous liquid. 0.06 parts by weight of 1,6-hexanediol diacrylate as a crosslinking agent was added to the obtained composition, and 2,2-dimethoxy-2-phenylbenzene as an additional photopolymerization initiator 0.02 parts by weight of ketone, 1 part by weight of benzotriazole (manufactured by Wako Pure Chemical Industries, Ltd.) as a rust preventive agent, and 1 part by weight of KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a decane coupling agent, and sufficiently stirred.

After the obtained mixture was subjected to vacuum defoaming, it was applied to a release-treated surface of a 50 μm-thick release polyethylene terephthalate film so as to have a thickness of 100 μm, so that the above-mentioned release type was paired. The release treatment surface of the phthalic acid phthalate film was coated on the coated surface, and was irradiated with a low-pressure mercury lamp for 5 minutes to obtain a transparent film coated with a release polyethylene terephthalate film on both sides. Adhesive tape (thickness 100 μm).

(Examples 35 to 46, Comparative Examples 8, 9)

The same manner as in Example 1 except that the monomer type and ratio of the (meth)acrylate copolymer, the decane coupling dose, the type and amount of the crosslinking agent, and the like were set as described in Tables 6 and 7. A (meth) acrylate copolymer and a transparent adhesive tape were obtained. Also, in the same manner as in the first embodiment, The maximum loss tangent temperature, the shear storage elastic modulus at 200 ° C, the gel fraction, and the molecular weight of the sol component were measured.

(Evaluation)

The transparent adhesive tape and the film laminate obtained in the examples and the comparative examples were evaluated by the above method (1) evaluation of whitening production (measurement of haze value), and (2) whitening when attached to an ITO film. The presence or absence, (3) resistance evaluation between ITO films, and (4) bubble generation state (flame resistance test). Further, the following evaluation was performed. The results are shown in Tables 5 to 7.

Among them, the molecular weight of the transparent adhesive tape obtained in Comparative Example 7 was not improved, and the band shape was not maintained, so that the adhesion evaluation to the glass plate and the tempered glass plate could not be performed.

Further, in Comparative Example 9, the adhesive solution was gelated during the polymerization, and the adhesive could not be prepared, and the data could not be collected.

(5) Adhesion evaluation (glass plate)

The obtained transparent adhesive tape having a thickness of 100 μm was cut into a flat shape of 25 mm × 100 mm. The release polyethylene terephthalate film on the side of the cut transparent adhesive tape was peeled off, and the exposed surface of the transparent adhesive tape was attached to a polyethylene terephthalate film having a thickness of 25 μm. Further, the release polyethylene terephthalate film on the other side of the transparent adhesive tape was peeled off, and the exposed surface of the transparent adhesive tape was bonded to a glass plate having a thickness of 1 mm (trade name "S-1214", manufactured by MATSUNAMI Co., Ltd. In this way, a laminated sample of a transparent adhesive tape and a polyethylene terephthalate film is sequentially laminated on the glass plate. Furthermore, when the exposed surface of the transparent adhesive tape is attached to the glass plate, a rubber roller of 2.0 kg is placed on the polyethylene terephthalate film on the upper surface to 300 The speed of mm/min allows the rubber roller to reciprocate once to perform the bonding. Thereafter, it was allowed to stand at 23 ° C and a relative humidity (RH) of 50% for 20 minutes to prepare a test sample.

For the obtained test samples, a tensile test in the 180° direction was performed at a peeling speed of 300 mm/min, and the adhesive force (N/25 mm) was measured.

(6) Adhesion evaluation (tempered glass plate)

The obtained transparent adhesive tape having a thickness of 100 μm was cut into a flat shape of 25 mm × 100 mm. The release polyethylene terephthalate film on the side of the cut transparent adhesive tape was peeled off, and the exposed surface of the transparent adhesive tape was attached to a polyethylene terephthalate film having a thickness of 25 μm. Further, the release polyethylene terephthalate film on the other side of the transparent adhesive tape was peeled off, and the exposed surface of the transparent adhesive tape was bonded to a tempered glass plate having a thickness of 1 mm (trade name "Gorilla Glass", manufactured by Corning Co., Ltd. In this way, a laminated sample of a transparent adhesive tape and a polyethylene terephthalate film is sequentially laminated on the tempered glass plate. Furthermore, when the exposed surface of the transparent adhesive tape is attached to the tempered glass plate, a rubber roller of 2.0 kg is placed on the polyethylene terephthalate film on the upper surface, and the rubber roller is driven at a speed of 300 mm/min. Round trip once to make a fit. Thereafter, it was allowed to stand at 23 ° C and a relative humidity (RH) of 50% for 20 minutes to prepare a test sample.

For the obtained test samples, a tensile test in the 180° direction was performed at a peeling speed of 300 mm/min, and the adhesive force (N/25 mm) was measured.

(7) Copper corrosion

The obtained transparent adhesive tape having a thickness of 100 μm was cut into a planar shape of 40 mm × 60 mm. Peel-off of the transparent adhesive tape on one side of the release For the ethylene terephthalate film, the exposed surface of the transparent adhesive tape was attached to a copper foil having a thickness of 35 μm. The test piece was placed in a thermo-hygrostat having a temperature of 85 ° C and a humidity of 85%, and the surface of the test piece was visually observed after 120 hours of visual observation. When there is no discoloration, it is evaluated as "○", and when there is discoloration, it is evaluated as "X".

[Industrial availability]

According to the present invention, it is possible to provide a transparent adhesive tape which can suppress generation of a subsequent interface even when, for example, a polycarbonate plate or an acrylic plate is used as the adherend, and the adherend generates outgassing in a high temperature environment. The foaming or bulging peeling also suppresses the deterioration of the metal film. Moreover, a film laminated body with a metal film manufactured by using the transparent adhesive tape, a cover panel-touch panel module laminated body, a cover panel-display panel module laminated body, a touch panel module-display Panel module laminated body and image display device.

1‧‧‧Video display devices for mobile phones, personal digital assistants, etc.

2‧‧‧Transparent adhesive tape of the invention

3‧‧‧ Cover panel

4‧‧‧Touch panel module

5‧‧‧Display panel module

6‧‧‧Metal film with metal film

7‧‧‧Transparent adhesive tape of the present invention

8‧‧‧Support (polyethylene terephthalate film, etc.)

9‧‧‧Metal laminate with metal film

10‧‧‧Touch panel module

1 is a schematic view showing an image display device such as a mobile phone or a personal digital assistant that is used to attach a cover panel for protecting a surface to a surface of a display panel module or a touch panel module using the transparent adhesive tape of the present invention. .

Claims (28)

A transparent adhesive tape having an adhesive layer composed of an adhesive composition containing a (meth) acrylate-based copolymer as a main component, characterized in that the adhesive layer has a dynamic viscoelastic spectrum at a frequency of 10 Hz. The loss tangent has a maximum value in the temperature range of -20 to 20 ° C, and the shear storage elastic modulus at 200 ° C is 2.5 × 10 ⁴ Pa or more, and the gel fraction is 70% by weight or more. The transparent adhesive tape of the sol component of the adhesive agent layer, wherein the converted weight molecular weight of the sol component of the adhesive layer satisfies the following formula (a), and the amount of the sol component having a molecular weight of 100,000 or less accounts for the entire weight ratio of the sol component. It satisfies the following formula (b), 250,000 ≧A ≧ 2000 × (100-B) ^1.5 (a) C ≦ 100-3 × (100-B) (b) where A represents the converted weight molecular weight of the sol component, B represents the gel fraction (% by weight) of the adhesive layer, and C represents the converted weight content (% by weight) of the sol component having a molecular weight of 100,000 or less contained in the sol component as a whole. The transparent adhesive tape according to claim 1 or 2, wherein the (meth) acrylate-based copolymer has the following structural unit: (meth) acrylate derived from a structure represented by the following formula (1) a constituent unit of the monomer and a constituent unit derived from a (meth) acrylate monomer having a structure represented by the following formula (2), In the formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkyl group having 4 to 14 carbon atoms, and a hydrogen atom of an alkyl group of R ² may be substituted with a cycloalkyl group. In the formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an alkyl group having 1 to 3 carbon atoms. The transparent adhesive tape of claim 3, wherein the (meth) acrylate monomer having the structure represented by the general formula (1) is selected from the group consisting of n-butyl (meth) acrylate and (meth) acrylate At least one of a group consisting of butyl ester, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, and isooctyl (meth)acrylate ( Methyl) acrylate monomer. The transparent adhesive tape of claim 3, wherein the (meth) acrylate monomer having the structure represented by the general formula (2) is selected from the group consisting of methyl (meth) acrylate and ethyl (meth) acrylate. At least one (meth) acrylate monomer of a group consisting of n-propyl (meth) acrylate and isopropyl (meth) acrylate. For example, the transparent adhesive tape of the third application patent scope, wherein The (meth) acrylate monomer having a structure represented by the formula (1) contains n-butyl (meth) acrylate, and the (meth) acrylate monomer having a structure represented by the formula (2) contains (meth)acrylic acid. Ethyl ester. The transparent adhesive tape of claim 3, wherein the (meth) acrylate-based copolymer further contains a constituent unit derived from a monomer having a bicyclic ring structure and one olefinic double bond. For example, the transparent adhesive tape of the seventh aspect of the patent application, wherein the double loop structure is an isocyclic ring. The transparent adhesive tape of claim 7, wherein the olefinic double bond is a double bond of a (meth) acrylonitrile group. The transparent adhesive tape of claim 7, wherein the olefinic double bond is a double bond of an acrylonitrile group. The transparent adhesive tape of claim 3, wherein the (meth) acrylate copolymer further has the following structural unit: a polyethylene oxide chain derived from ethylene oxide having a repeat number of 8 to 45 And a constituent unit of one monomer of an olefinic double bond. The transparent adhesive tape of claim 11, wherein the monomer having a polyethylene oxide chain having an ethylene oxide repeating number of 8 to 45 has a monomer having a structure represented by the following formula (3) , In the formula (3), R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents an alkyl group having 1 to 30 carbon atoms, and n represents an integer of 8 to 45. The transparent adhesive tape of claim 12, wherein, in the formula (3), R ⁵ is a hydrogen atom or a methyl group, R ⁶ is an alkyl group having a carbon number of 18, and n is 30. The transparent adhesive tape of claim 12, wherein, in the formula (3), R ⁵ is a hydrogen atom or a methyl group, R ⁶ is an alkyl group having 1 carbon atom, and n is 23. The transparent adhesive tape of the third aspect of the invention, wherein the (meth) acrylate-based copolymer further contains a constituent unit derived from a monomer having a structure represented by the following formula (4), and has a hydroxyl value of 10 ~150mgKOH/g, In the formula (4), R ⁷ represents a hydrogen atom or a methyl group, and R ⁸ represents an alkyl group having a hydroxyl group. The transparent adhesive tape according to claim 1 or 2, wherein the adhesive composition further contains 0.01 to 5 parts by weight of the decane coupling agent per 100 parts by weight of the (meth) acrylate-based copolymer. The transparent adhesive tape according to the first or second aspect of the invention, wherein the adhesive composition contains 0.01 to 10 parts by weight of the rust inhibitor with respect to 100 parts by weight of the (meth)acrylate copolymer. Such as the transparent adhesive tape of claim 17 of the patent scope, wherein the rust inhibitor It is a benzotriazole or an alkylbenzotriazole. The transparent adhesive tape of claim 1 or 2, wherein the adhesive composition further comprises an isocyanate-based crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, and a metal chelate compound. At least one crosslinking agent in the group consisting of crosslinking agents. The transparent adhesive tape of claim 1 or 2, wherein the adhesive layer has a thickness of 5 μm to 1 mm. The transparent adhesive tape of claim 1 or 2 is used for two films with a metal film attached to each other, a cover panel and a touch panel module, a cover panel and a display panel module, or The touch panel module is followed by the display panel module. A film laminate with a metal film, which is a film with two metal films, according to the patent scopes 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, The transparent adhesive tape of 14, 15, 16, 17, 18, 19, 20 or 21 is then formed. A cover panel-touch panel module laminated body, which is a cover panel and a touch panel module, according to the patent scopes 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, The transparent adhesive tape of 13, 14, 15, 16, 17, 18, 19, 20 or 21 is then formed. The cover panel-touch panel module laminate of claim 23, wherein the cover panel is a polycarbonate plate or an acrylic plate. A cover panel-display panel module laminated body, which is a cover panel and a display panel module, according to the patent scopes 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or 21 transparent adhesive tapes were formed. For example, the cover panel-display panel module laminate of claim 25, wherein the cover panel is a polycarbonate plate or an acrylic plate. A touch panel module-display panel module laminated body, which is a touch panel module and a display panel module, according to the patent scope 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, The transparent adhesive tape of 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or 21 is then formed. An image display device comprising: a film laminate with a metal film in claim 22; a cover panel-touch panel module laminate of claim 23 or 24, and a patent application scope 25 or 26 The cover panel of the item-display panel module laminate, or the touch panel module-display panel module laminate of claim 27th.