JP2020139108A - Adhesive composition for organic EL display device, adhesive layer for organic EL display device, polarizing film with adhesive layer for organic EL display device, and organic EL display device - Google Patents

Abstract

To provide an adhesive layer for an organic EL display device, which can suppress deterioration of an organic EL element, has high transparency, has low dielectric characteristics not adversely influencing sensitivity of a sensor, and is excellent in resistance to drop impact.SOLUTION: An adhesive layer is formed of an adhesive composition containing a (meth)acrylic polymer and an ultraviolet absorber, in which, with respect to the (meth)acrylic polymer, a rate (a) of alkyl (meth)acrylate (A) having 8 or less alkyl carbon atoms and a rate (b) of alkyl (meth)acrylate (B) having 12 to 24 alkyl carbon atoms satisfy an equation (1): 60≤{(a)+(b)} and an equation (2): 2<{(a)/(b)}≤5, further a peak value (Tg) of tanδ is -20 to -5°C, further the peak value is in a range of 1.6 to 2.6, transmittance at a wavelength of 380 nm is 10% or less, transmittance at a wavelength of 450 nm is 85% or more, total light transmittance is 85% or more, and haze is 1% or less.SELECTED DRAWING: Figure 4

Description

The present invention relates to an adhesive composition for an organic EL (electroluminescent) display device (OLED). The present invention also relates to an organic EL display device pressure-sensitive adhesive layer formed from the organic EL display device pressure-sensitive adhesive composition, and a polarizing film with a pressure-sensitive adhesive layer having the pressure-sensitive adhesive layer. Furthermore, the present invention relates to an organic EL display device using the pressure-sensitive adhesive layer and / or the polarizing film.

In recent years, organic EL display devices equipped with organic EL panels have come to be widely used in various applications such as mobile phones, car navigation devices, personal computer monitors, and televisions. The organic EL display device usually has a circularly polarizing plate (polarizing plate and 1) on the visible side surface of the organic EL panel in order to prevent external light from being reflected by a metal electrode (cathode) and visually recognized as a mirror surface. (A laminate of / 4 wave plates, etc.) is arranged. Further, a decorative panel or the like may be further laminated on the circularly polarizing plate laminated on the visible side surface of the organic EL panel. The constituent members of the organic EL display device such as the circularly polarizing plate and the decorative panel are usually laminated via a bonding material such as an adhesive layer or an adhesive layer.

In an image display device such as an organic EL display device, the components and the like in the image display device may be deteriorated by the incident ultraviolet light, and in order to suppress the deterioration due to the ultraviolet light, a layer containing an ultraviolet absorber. It is known to provide. Specifically, for example, it has at least one ultraviolet absorbing layer, has a light transmittance of 30% or less at a wavelength of 380 nm, and has a visible light transmittance of 80% or more on a wavelength side longer than the wavelength of 430 nm. A transparent double-sided pressure-sensitive adhesive sheet for an image display device (see, for example, Patent Document 1) and a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer containing an acrylic polymer and a triazine-based ultraviolet absorber are known (see, for example, Patent Document 2). ..

Further, the organic EL display device is used in combination with a touch panel having a capacitance type touch sensor. Capacitive touch sensors are required to have higher performance as they become more widespread. Therefore, high performance is also required for the adhesive layer applied to the capacitive touch sensor. However, due to the thinner module, larger screen, and higher definition of the organic EL element in the organic EL display device, the driving noise when driving the display of the organic EL panel adversely affects the sensing of the capacitive touch sensor. , There is a concern that malfunction may occur. The malfunction due to the driving noise may occur when the dielectric constant of the pressure-sensitive adhesive layer is high. Therefore, as a pressure-sensitive adhesive for forming a pressure-sensitive pressure-sensitive adhesive layer, for example, a pressure-sensitive adhesive based on a (meth) acrylic polymer containing an alkyl (meth) acrylate having a long-chain alkyl group as a main component has been proposed. (For example, Patent Document 3). According to the adhesive layer having a low dielectric constant, the influence of the driving noise from the organic EL panel on the capacitive touch sensor can be reduced.

JP 2012-2111305 Japanese Unexamined Patent Publication No. 2013-75978 Japanese Unexamined Patent Publication No. 2013-082880

The adhesive sheet described in Patent Documents 1 and 2 can control the transmittance of light having a wavelength of 380 nm. However, when the adhesive sheet is used in an organic EL display device, the organic EL element can be used for a long time. May deteriorate, and it was not enough. This is because the pressure-sensitive adhesive sheets described in Patent Documents 1 and 2 can absorb light having a wavelength of 380 nm, but have a wavelength region (380 nm) shorter than the light emitting region (longer wavelength side than 430 nm) of the organic EL element. It is considered that the light of ~ 430 nm) is not sufficiently absorbed and the transmitted light causes deterioration.

Therefore, in order to suppress the deterioration of the organic EL element, the transmission of light having a wavelength (380 nm to 430 nm) shorter than the light emitting region (longer wavelength side than 430 nm) of the organic EL element is suppressed, and the organic EL element is described. It is necessary to use a layer having a sufficient transmittance of visible light in the light emitting region of the above and having high transparency in an organic EL display device.

On the other hand, organic EL display devices are used for various purposes. For example, when they are used for module devices for mobile applications, drop impact resistance is required. Therefore, the pressure-sensitive adhesive layer used in the organic EL display device is required to have resistance to peeling at the time of drop impact as drop impact resistance. In particular, the low dielectric constant pressure-sensitive adhesive layer described in Patent Document 3 has a high glass transition point (Tg), and therefore has insufficient drop impact resistance. In particular, the high level of drop impact resistance could not be satisfied.

Therefore, the present invention has a low dielectric property that can suppress deterioration of the organic EL element, has high transparency, and does not adversely affect the sensor sensitivity, and has a high degree of drop impact resistance. It is an object of the present invention to provide an adhesive layer for an organic EL display device having excellent characteristics.

The present invention also provides a polarizing film with an adhesive layer having a polarizing film and an adhesive layer for an organic EL display device, and the present invention further provides a polarizing film with the adhesive layer and / or the adhesive layer. It is an object of the present invention to provide an organic EL display device including.

As a result of diligent studies to solve the above problems, the present inventors have found the following pressure-sensitive adhesive layer for an organic EL display device and have completed the present invention.

That is, the present invention is a pressure-sensitive adhesive layer for an organic EL display device formed from a pressure-sensitive adhesive composition containing a (meth) acrylic polymer and an ultraviolet absorber.
The (meth) acrylic polymer includes an alkyl (meth) acrylate (A) having an alkyl group having 8 or less carbon atoms at the ester terminal and an alkyl (meth) acrylate (B) having an alkyl group having 12 to 24 carbon atoms at the ester terminal. ), Which was obtained by polymerizing a monomer component containing a monofunctional monomer component.
The ratio (a:% by weight) of the alkyl (meth) acrylate (A) and the ratio (b:% by weight) of the alkyl (meth) acrylate (B) to 100% by weight of the monofunctional monomer component are as follows. Satisfying (1) and equation (2)
Equation (1): 60 ≦ {(a) + (b)}
Equation (2): 2 << {(a) / (b)} ≦ 5
And the adhesive layer is
The peak value (Tg) of tan δ when the dynamic viscoelasticity is measured at a frequency of 1 Hz is -20 to -5 ° C, and the tan δ at the peak value is in the range of 1.6 or more and 2.6 or less. ,
The transmittance at a wavelength of 380 nm is 10% or less, and the transmittance at a wavelength of 450 nm is 85% or more.
An adhesive layer for an organic EL display device, characterized in that the total light transmittance is 85% or more and the haze is 1% or less.
Regarding.

In the pressure-sensitive adhesive layer for an organic EL display device, it is preferable that the maximum absorption wavelength of the absorption spectrum of the ultraviolet absorber exists in a wavelength region of 300 to 400 nm.

In the pressure-sensitive adhesive layer for an organic EL display device, the monofunctional monomer component can further contain at least one cohesive monomer selected from a cyclic nitrogen-containing monomer and an alicyclic structure-containing monomer. The proportion of the cohesive monomer in the monofunctional monomer component is preferably 10 to 22% by weight.

In the pressure-sensitive adhesive layer for an organic EL display device, the monofunctional monomer component can further contain a hydroxyl group-containing monomer. The proportion of the hydroxyl group-containing monomer in the monofunctional monomer component is preferably 1.5 to 10% by weight.

In the pressure-sensitive adhesive layer for an organic EL display device, the monomer component can further contain 3 parts by weight or less of a polyfunctional monomer with respect to 100 parts by weight of the monofunctional monomer component.

In the pressure-sensitive adhesive layer for an organic EL display device, the pressure-sensitive adhesive composition can further contain a dye compound existing in a wavelength region in which the maximum absorption wavelength of the absorption spectrum is 380 to 430 nm.

In the pressure-sensitive adhesive layer for an organic EL display device, the pressure-sensitive adhesive composition can further contain 3 parts by weight or less of a cross-linking agent with respect to 100 parts by weight of the (meth) acrylic polymer.

In the pressure-sensitive adhesive layer for an organic EL display device, the pressure-sensitive adhesive composition can further contain 3 parts by weight or less of a silane coupling agent with respect to 100 parts by weight of the (meth) acrylic polymer.

In the pressure-sensitive adhesive layer for an organic EL display device, the pressure-sensitive adhesive composition can further contain a photopolymerization initiator.

In the pressure-sensitive adhesive layer for an organic EL display device, the pressure-sensitive adhesive composition can further contain an antioxidant.

The pressure-sensitive adhesive layer for an organic EL display device preferably has a relative permittivity of 4.0 or less at a frequency of 100 kHz.

The pressure-sensitive adhesive layer for an organic EL display device preferably has a gel fraction of 40 to 90% by weight.

The pressure-sensitive adhesive layer for an organic EL display device preferably has a 180-degree peel adhesive force (peeling speed 300 mm / min) with respect to non-alkali glass of 7 N / 20 mm or more.

The pressure-sensitive adhesive layer for an organic EL display device preferably has a separator on at least one side.

The present invention also relates to a polarizing film having an adhesive layer for an organic EL display device and a polarizing film with an adhesive layer for an organic EL display device.

The polarizing film with an adhesive layer for an organic EL display device is such that the polarizing film is provided with a transparent protective film on one surface of a polarizer and has a retardation film on the other surface. It is preferable that the pressure-sensitive adhesive layer for a display device is provided on the surface of the retardation film opposite to the surface in contact with the polarizer and / or the surface of the transparent protective film opposite to the surface in contact with the polarizer.

The polarizing film with an adhesive layer for an organic EL display device has an adhesive layer having a first adhesive layer, a transparent protective film, a polarizer, a second adhesive layer, a retardation film, and a third adhesive layer in this order. It's a polarizing film
Of the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer, and the third pressure-sensitive adhesive layer, at least one pressure-sensitive adhesive layer is preferably the pressure-sensitive adhesive layer for an organic EL display device.

In the polarizing film with an adhesive layer for an organic EL display device, it is preferable that the retardation film is a 1/4 wave plate and the polarizing film is a circular polarizing film.

The present invention also relates to an organic EL display device characterized in that at least one polarizing film with an adhesive layer for an organic EL display device or a polarizing film with an adhesive layer for an organic EL display device is used.

The organic EL display device is an organic EL display device with a touch panel having an organic EL panel, a circularly polarizing film provided in order from the visual side of the organic EL panel, and a touch panel having at least one sensor film.
It is preferable in an embodiment in which the pressure-sensitive adhesive layer for an organic EL display device is provided so as to be in contact with at least one sensor film on the visual side of the circularly polarizing film.

As described above, the pressure-sensitive adhesive layer for an organic EL display device is suitable as a pressure-sensitive adhesive layer for a touch panel used for contacting and providing at least one sensor film in the organic EL display device with a touch panel.

The pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer for an organic EL display device of the present invention is formed from a pressure-sensitive adhesive composition containing an ultraviolet absorber in addition to an acrylic polymer as a base polymer. The ultraviolet absorber can suppress deterioration due to ultraviolet light where light in the near-ultraviolet to ultraviolet region is not transmitted. Further, the pressure-sensitive adhesive layer for an organic EL display device of the present invention has high transparency, and deterioration of the organic EL element can be suppressed without interfering with the display performance of the organic EL element. Therefore, the organic EL display device using the pressure-sensitive adhesive layer for the organic EL display device and / or the polarizing film with the pressure-sensitive adhesive layer including the pressure-sensitive adhesive layer for the organic EL display device of the present invention has excellent weather resistance and deterioration resistance. The life can be extended.

Further, in order to reduce the dielectric constant, it is considered that the dipole moment of the molecule should be reduced and the molar volume should be increased according to the Clausius-Mossotti equation. The acrylic polymer according to the present invention has an alkyl (meth) acrylate (B) having a long-chain alkyl group as a monomer unit, and has a low dielectric constant to the extent that the pressure-sensitive adhesive layer does not adversely affect the sensor sensitivity. Can be transformed into. The adhesive layer having a suppressed relative permittivity in this way can reduce the influence of malfunction due to the influence of drive noise from the organic EL panel on the capacitive touch sensor. Therefore, the pressure-sensitive adhesive layer of the present invention can be suitably applied to a touch sensor having a fast response speed and high sensitivity.

Further, the acrylic polymer according to the present invention contains two types of (meth) acrylates (A) and (B) having different carbon atoms in the alkyl group in a predetermined ratio, and has a long length. Despite having an alkyl (meth) acrylate (B) having an alkyl group in the chain as a monomer unit, the pressure-sensitive adhesive layer of the present invention has a glass transition temperature (Tg) of -5 related to the peak value of tan δ. The temperature or less and tan δ at the peak value are controlled within a predetermined range. As described above, according to the present invention, while maintaining the adhesive properties as the adhesive layer and suppressing the relative permittivity to the extent that the sensor sensitivity is not adversely affected as described above, a high degree of drop impact resistance is achieved. An adhesive layer having is obtained. The pressure-sensitive adhesive layer of the present invention is formed by interlayer-filling a printed glass (cover glass, etc.), an optical film, a capacitive touch sensor, and an air layer above the organic EL display device in an organic EL display device. It is possible to provide a mobile module device having excellent peeling resistance at the time of a drop impact.

(A)-(c) is a cross-sectional view schematically showing an embodiment of a polarizing film with an adhesive layer for an organic EL display device of the present invention. It is sectional drawing which shows typically one Embodiment of the organic EL display device of this invention. It is sectional drawing which shows typically one Embodiment of the organic EL display device of this invention. It is sectional drawing which shows typically one Embodiment of the organic EL display device of this invention.

1. 1. Adhesive layer for organic EL display device The pressure-sensitive adhesive layer for organic EL display device of the present invention is formed from a pressure-sensitive adhesive composition containing a (meth) acrylic polymer and an ultraviolet absorber.

(1) Partial Polymer of Monomer Component and (Meta) Acrylic Polymer The (meth) acrylic polymer contained in the pressure-sensitive adhesive composition is an alkyl (meth) acrylate having an alkyl group having 8 or less carbon atoms at the ester terminal. (A) and polymerizing a partial polymer of a monomer component containing a monofunctional monomer component containing an alkyl (meth) acrylate (B) having an alkyl group having 12 to 24 carbon atoms at the ester terminal and / or the monomer component. Obtained by In addition, "alkyl (meth) acrylate" refers to alkyl acrylate and / or alkyl methacrylate, and has the same meaning as (meth) of the present invention.

Further, the alkyl (meth) acrylate (A) and the alkyl (meth) acrylate (B) are the ratio of the alkyl (meth) acrylate (A) to 100% by weight of the monofunctional monomer component in the monomer component. The ratio (b:% by weight) of a:% by weight) and the alkyl (meth) acrylate (B) is used so as to satisfy the following formulas (1) and (2).
Equation (1): 60 ≦ {(a) + (b)}
Equation (2): 2 << {(a) / (b)} ≦ 5
By using the alkyl (meth) acrylate (A) and the alkyl (meth) acrylate (B) in the above range, these monomer units can be introduced into the (meth) acrylic polymer in a well-balanced manner, and a pressure-sensitive adhesive can be used. It is possible to impart low dielectric properties and peeling resistance at the time of drop impact to the layer.

The total {(a) + (b)} of the ratio (a) of the alkyl (meth) acrylate (A) and the ratio (b) of the alkyl (meth) acrylate (B) according to the formula (1) is It is 60% by weight or more with respect to 100% by weight of the monofunctional monomer component in the monomer component. From the viewpoint of easy balance of adhesive properties and drop impact resistance, the total is preferably 65% by weight or more, more preferably 70% by weight or more, and further preferably 75% by weight or more. Is preferable. On the other hand, the total may be 100% by weight, but it is preferably 95% by weight or less from the viewpoints of securing cohesive force and cross-linking point, securing elastic modulus at high temperature, and wettability to the adherend. Further, it is preferably 90% by weight or less.

Further, the ratio of the ratio (a) of the alkyl (meth) acrylate (A) and the ratio (b) of the alkyl (meth) acrylate (B) according to the formula (2) {(a) / (b)}. Is in the range of more than 2 and 5 or less, and is preferably 2.2 to 4 from the viewpoint of achieving both a relative permittivity and a high degree of drop impact resistance, further preferably 2.3 to 4, and further 2.4. ~ 3 is preferable.

The proportion (a) of the alkyl (meth) acrylate (A) is preferably adjusted in the range of 40 to 83% by weight, more preferably 44 to 78% by weight, and further preferably 48 to 73% by weight. % Is preferable from the viewpoint of ensuring a high degree of drop impact resistance and adhesive properties. The proportion (b) of the alkyl (meth) acrylate (B) is preferably adjusted in the range of 10 to 33% by weight, more preferably 14 to 30% by weight, and further preferably 18 to 27% by weight. It is preferable because it can secure drop impact resistance while reducing the relative permittivity.

<Alkyl (meth) acrylate (A)>
The alkyl group having 8 or less carbon atoms in the alkyl (meth) acrylate (A) can be either a straight chain or a branched chain, but can impart adhesiveness to the pressure-sensitive adhesive layer and resist drop impact. From the viewpoint, the number of carbon atoms of the alkyl group is preferably 2 to 8, and more preferably 4 to 8. Further, the alkyl (meth) acrylate (A) is preferably an alkyl acrylate from the viewpoint that the glass transition point (Tg) is relatively low and the radical polymerization reactivity is relatively fast. Further, the alkyl (meth) acrylate (A) preferably has a homopolymer Tg of −90 to −20 ° C., more preferably −85 to −30 ° C., from the viewpoint of imparting adhesiveness to the pressure-sensitive adhesive layer. Further, it is preferably −80 to −40 ° C. The Tg of the homopolymer is a value measured by differential thermal simultaneous analysis (TG-DTA) (the same applies to the measurement of the Tg of the homopolymer).

Examples of the alkyl (meth) acrylate (A) include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, and t-butyl (meth) acrylate. Isobutyl (meth) acrylate, n-pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, isoamyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl Examples thereof include (meth) acrylate, isooctyl (meth) acrylate, and n-nonyl (meth) acrylate. These can be used alone or in combination.

The alkyl (meth) acrylate (A) has an alkyl group having 1 to 4 carbon atoms at the ester terminal and an alkyl (meth) acrylate (A1) having 5 to 5 carbon atoms from the viewpoint of controlling high drop impact resistance and adhesive properties. It is preferable to use an alkyl (meth) acrylate (A2) having an alkyl group of 8 at the ester terminal in combination. The alkyl (meth) acrylate (A1) is preferably n-butyl (meth) acrylate, and the alkyl (meth) acrylate (A2) is preferably 2-ethylhexyl (meth) acrylate. Further, the ratio (a1:% by weight) of the alkyl (meth) acrylate (A1) and the ratio (a2:% by weight) of the alkyl (meth) acrylate (A2) are expressed by the following formula (3):
It is preferable that the formula (3): 1 ≦ {(a1) / (a2)} ≦ 15 is satisfied.
The ratio {(a1) / (a2)} is preferably 1.1 to 12, and more preferably 1.2 to 10.

<Alkyl (meth) acrylate (B)>
The alkyl group having 12 to 24 carbon atoms in the alkyl (meth) acrylate (B) can be either a straight chain or a branched chain, but is branched from the viewpoint of satisfying a low dielectric constant and an appropriate elastic modulus. It is preferably a chain, and more preferably a branched chain alkyl group having 14 to 22 carbon atoms. Further, in the case of a linear alkyl group, the number of carbon atoms is preferably 18 or more from the viewpoint of satisfying a low dielectric constant and an appropriate elastic modulus. It is considered that the long-chain alkyl group of the alkyl (meth) acrylate has an increased molar volume due to the branching of the alkyl group and a decrease in the dipole moment to obtain a pressure-sensitive adhesive layer having a balance between the two. The alkyl (meth) acrylate (B) is preferably an alkyl acrylate from the viewpoint of having a relatively low glass transition point (Tg) and a relatively fast radical polymerization reactivity. Further, the alkyl (meth) acrylate (B) preferably has a homopolymer Tg of −80 to 0 ° C., and more preferably −80 to 0 ° C., from the viewpoint of imparting a low dielectric constant and an appropriate elastic modulus to the pressure-sensitive adhesive layer. It is preferably 75 to −5 ° C., more preferably −70 to −10 ° C.

Examples of the alkyl (meth) acrylate (B) include lauryl (meth) acrylate, isododecyl (meth) acrylate, tridecyl (meth) acrylate, isotridecyl (meth) acrylate, tetradecyl (meth) acrylate, and pentadecyl (meth) acrylate. Isopentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, isohexadecyl (meth) acrylate, isoheptadecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, etc. Be done.

<Copolymerization monomer>
The monofunctional monomer in the monomer component can contain a copolymerization monomer other than the alkyl (meth) acrylates (A) and (B). The copolymerizable monomer can be used as the remainder of the alkyl (meth) acrylates (A) and (B) in the monofunctional monomer.

The copolymerization monomer can include, for example, at least one cohesive monomer selected from a cyclic nitrogen-containing monomer and an alicyclic structure-containing monomer. The cohesive monomer is preferable because the homopolymer has a high Tg, and it is possible to reduce the dielectric constant, secure the cohesive force, and maintain a high elastic modulus in the high temperature region (80 ° C.). The Tg of the homopolymer of the cohesive monomer is preferably 0 to 200 ° C, more preferably 5 to 180 ° C, and further preferably 10 to 160 ° C.

As the cyclic nitrogen-containing monomer, a monomer having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a cyclic nitrogen structure can be used without particular limitation. The cyclic nitrogen structure preferably has a nitrogen atom in the cyclic structure. Examples of the cyclic nitrogen-containing monomer include lactam-based vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazin, vinylpyrazine, vinylpyrrole, and vinyl. Examples thereof include vinyl-based monomers having a nitrogen-containing heterocycle such as imidazole, vinyloxazole, and vinylmorpholin. In addition, (meth) acrylic monomers containing a heterocycle such as a morpholine ring, a piperidine ring, a pyrrolidine ring, and a piperazine ring can be mentioned. Specific examples thereof include N-acryloyl morpholine, N-acryloyl piperidine, N-methacryloyl piperidine, N-acryloyl pyrrolidine and the like. Among the cyclic nitrogen-containing monomers, a lactam vinyl monomer is preferable.

As the alicyclic structure-containing monomer, those having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having an alicyclic structure can be used without particular limitation. .. The alicyclic structure is a cyclic hydrocarbon structure, and is preferably 5 or more carbon atoms, preferably 6 to 24 carbon atoms, more preferably 8 to 20 carbon atoms, and more preferably 8 to 20 carbon atoms from the viewpoint of reducing the dielectric constant. It is more preferably 10 to 18. Examples of the alicyclic structure-containing monomer include cyclopropyl (meth) acrylate, cyclobutyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, cyclooctyl (meth) acrylate, and isobornyl. Examples thereof include (meth) acrylic monomers such as (meth) acrylate, dicyclopentanyl (meth) acrylate, HPMPA (chemical formula 1 below), TMA-2 (chemical formula 2 below), and HCPA (chemical formula 3 below). .. Among these, cyclohexyl (meth) acrylate, HPMPA, TMA-2 and HCPA are preferable, and cyclohexyl (meth) acrylate, HPMPA and TMA-2 are particularly preferable.

The proportion of the cohesive monomer is preferably 10 to 22% by weight, more preferably 12 to 20% by weight, based on the total amount of the monofunctional monomer component.

Further, as the copolymerization monomer in the monofunctional monomer, a hydroxyl group-containing monomer can be included. As the hydroxyl group-containing monomer, a monomer having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a hydroxyl group can be used without particular limitation. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl ( Hydroxyalkyl (meth) acrylates such as meta) acrylates, 6-hydroxyhexyl (meth) acrylates, 8-hydroxyoctyl (meth) acrylates, 10-hydroxydecyl (meth) acrylates, 12-hydroxylauryl (meth) acrylates; (4) Examples thereof include hydroxyalkylcycloalkane (meth) acrylates such as −hydroxymethylcyclohexyl) methyl (meth) acrylate. Other examples include hydroxyethyl (meth) acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether and the like. These can be used alone or in combination. Among these, hydroxyalkyl (meth) acrylate is preferable.

The ratio of the hydroxyl group-containing monomer is usually preferably in the range of 0.1 to 20% by weight from the viewpoint of enhancing the adhesive force and the cohesive force with respect to the total amount of the monofunctional monomer. In particular, from the viewpoint of controlling the Tg of the pressure-sensitive adhesive layer within the range of the present invention to satisfy good drop impact resistance (peeling resistance at the time of drop impact), it is preferably 1.5 to 10% by weight. The proportion of the hydroxyl group-containing monomer is more preferably 2% by weight or more, and further preferably 3% by weight or more. The more hydroxyl groups there are, the better the adhesive strength (to glass), the higher the elastic modulus in the high temperature range (80 ° C) can be maintained, and it is advantageous in preventing peeling in the reliability test. On the other hand, if the amount of the hydroxyl group-containing monomer is too large, the dielectric constant tends to be high, the pressure-sensitive adhesive layer may be hardened, the adhesive strength may be lowered, and the viscosity of the pressure-sensitive adhesive may be too high. The hydroxyl group-containing monomer is preferably 9% by weight or less, preferably 8% by weight, based on the total amount of the monofunctional monomer component forming the (meth) acrylic polymer, because gelation may occur. % Or less is more preferable, and 7% by weight or less is further preferable.

Further, as the copolymerization monomer in the monofunctional monomer, a functional group-containing monomer other than the above can be contained, and examples thereof include a carboxyl group-containing monomer and a monomer having a cyclic ether group.

As the carboxyl group-containing monomer, a monomer having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a carboxyl group can be used without particular limitation. Examples of the carboxyl group-containing monomer include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid and the like. Can be used alone or in combination. These anhydrides can be used for itaconic acid and maleic acid. Among these, acrylic acid and methacrylic acid are preferable, and acrylic acid is particularly preferable. A carboxyl group-containing monomer can be arbitrarily used as the monomer component used in the production of the (meth) acrylic polymer of the present invention, and on the other hand, the carboxyl group-containing monomer may not be used.

Examples of the monomer having a cyclic ether group include those having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a cyclic ether group such as an epoxy group or an oxetane group. It can be used without particular limitation. Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether and the like. Examples of the oxetane group-containing monomer include 3-oxetanylmethyl (meth) acrylate, 3-methyl-oxetanylmethyl (meth) acrylate, 3-ethyl-oxetanylmethyl (meth) acrylate, and 3-butyl-oxetanylmethyl (meth) acrylate. , 3-Hexyl-oxetanylmethyl (meth) acrylate and the like. These can be used alone or in combination.

The ratio of the carboxyl group-containing monomer and the monomer having a cyclic ether group is preferably 8% by weight or less, more preferably 5% by weight or less, based on the total amount of the monofunctional monomer. When the pressure-sensitive adhesive layer of the present invention is also used in a mode of contacting with a sensor film, it is preferable to adopt a mode in which a carboxyl group-containing monomer is not used.

Examples of the copolymerization monomer in the monofunctional monomer include CH ₂ = C (R ¹ ) COOR ² (where R ¹ is a hydrogen or methyl group, R ² is an alkyl group having 9 to 11 carbon atoms, and the number of carbon atoms is carbon. Examples thereof include alkyl (meth) acrylates represented by 1 to 3 substituted alkyl groups and cyclic cycloalkyl groups).

Here, the substituent of the substituted alkyl group having 1 to 3 carbon atoms as R ² is preferably an aryl group having 3 to 8 carbon atoms or an aryloxy group having 3 to 8 carbon atoms. .. The aryl group is not limited, but a phenyl group is preferable.

Examples of such a monomer represented by CH ₂ = C (R ¹ ) COOR ² include phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, and 3,3,5-trimethylcyclohexyl. Examples thereof include (meth) acrylate and isobornyl (meth) acrylate. These can be used alone or in combination.

The ratio of the (meth) acrylate represented by CH ₂ = C (R ¹ ) COOR ² is preferably 10% by weight or less based on the total amount of the monofunctional monomer.

Other copolymerization monomers include vinyl acetate, vinyl propionate, styrene, α-methylstyrene; (meth) polyethylene glycol acrylate, (meth) polypropylene glycol acrylate, (meth) methoxyethylene glycol acrylate, (meth). Glycol-based acrylic ester monomer such as methoxypolypropylene glycol acrylate; Acrylic acid ester-based monomer such as tetrahydrofurfuryl (meth) acrylate, fluorine (meth) acrylate, silicone (meth) acrylate and 2-methoxyethyl acrylate; containing amide group Monomers, amino group-containing monomers, imide group-containing monomers, vinyl ether monomers and the like can also be used.

Further, a silane-based monomer containing a silicon atom and the like can be mentioned. Examples of the silane-based monomer include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, and 8-vinyloctyltrimethoxysilane. , 8-Vinyloctyloxydecyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, 10-acryloyloxydecyltriethoxysilane and the like.

In addition to the above-exemplified monofunctional monomer, the monomer component forming the (meth) acrylic polymer of the present invention contains, if necessary, a polyfunctional monomer in order to adjust the cohesive force of the pressure-sensitive adhesive. be able to.

The polyfunctional monomer is a monomer having at least two polymerizable functional groups having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group, and is, for example, a (poly) ethylene glycol di (meth) acrylate. (Poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,2-ethylene Glycoldi (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, trimethyl propantri (meth) acrylate, tetramethylol methanetri (meth) acrylate, etc. Ester compounds of polyhydric alcohol and (meth) acrylic acid; allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyldi (meth) acrylate, hexyldi (meth) acrylate, etc. Can be mentioned. Among these, trimethylolpropane tri (meth) acrylate, hexanediol di (meth) acrylate, and dipentaerythritol hexa (meth) acrylate can be preferably used. The polyfunctional monomer may be used alone or in combination of two or more.

The amount of the polyfunctional monomer used varies depending on its molecular weight, the number of functional groups, and the like, but it is preferably 3 parts by weight or less, more preferably 2 parts by weight or less, based on 100 parts by weight of the total monofunctional monomer. More preferably, it is 1 part by weight or less. The lower limit is not particularly limited, but is preferably 0 parts by weight or more, and more preferably 0.001 parts by weight or more. Further, the amount used is preferably 0.01 to 2 parts by weight, preferably 0.02 to 1 part by weight, and preferably 0.03 to 0.8 parts by weight. When the amount of the polyfunctional monomer used is within the above range, the adhesive strength can be improved.

For the production of the (meth) acrylic polymer, known production methods such as solution polymerization, radiation polymerization such as ultraviolet (UV) polymerization, bulk polymerization, and various radical polymerizations such as emulsion polymerization can be appropriately selected. Further, the obtained (meth) acrylic polymer may be any of a random copolymer, a block copolymer, a graft copolymer and the like.

Further, in the present invention, a partial polymer of the monomer component can also be preferably used.

When the (meth) acrylic polymer is produced by radical polymerization, the polymerization can be carried out by appropriately adding a polymerization initiator, a chain transfer agent, an emulsifier and the like used for radical polymerization to the monomer component. The polymerization initiator, chain transfer agent, emulsifier and the like used in the radical polymerization are not particularly limited and can be appropriately selected and used. The weight average molecular weight of the (meth) acrylic polymer can be controlled by the amount of the polymerization initiator and the chain transfer agent used, and the reaction conditions, and the amount used is appropriately adjusted according to these types.

For example, in solution polymerization and the like, for example, ethyl acetate, toluene and the like are used as the polymerization solvent. As a specific example of solution polymerization, the reaction is carried out under an inert gas stream such as nitrogen, a polymerization initiator is added, and usually at about 50 to 70 ° C. under reaction conditions of about 5 to 30 hours.

Examples of the thermal polymerization initiator used for solution polymerization and the like include 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, and 2,2'-azobis (2). -Methylpropionic acid) dimethyl, 4,4'-azobis-4-cyanovalerian acid, azobisisovaleronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis [2- (5-Methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis (2-methylpropionamidine) disulfate, 2,2'-azobis (N, N'-dimethyleneisobutyry) Azobisisobutyin), 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropion amidine] hydrate (VA-057, manufactured by Wako Pure Chemical Industries, Ltd.) and other azo initiators; persulfate. Persulfates such as potassium and ammonium persulfate, di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxy Neodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2 -Ethylhexanoate, di (4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di (t-hexylperoxy) cyclohexane, t-butylhydroperoxide, Peroxide-based initiators such as hydrogen peroxide, combinations of persulfate and sodium hydrogen sulfite, and redox-based initiators that combine peroxides and reducing agents such as combinations of peroxide and sodium ascorbate. It can, but is not limited to these.

The polymerization initiator may be used alone or in combination of two or more, but it is preferably about 1 part by weight or less based on 100 parts by weight of the total amount of the monomer components. , 0.005 to 1 part by weight is more preferable, and about 0.02 to 0.5 part by weight is further preferable.

When 2,2'-azobisisobutyronitrile is used as the polymerization initiator, the amount of the polymerization initiator used is about 0.2 parts by weight or less with respect to 100 parts by weight of the total amount of the monomer components. It is preferably about 0.06 to 0.2 parts by weight, and more preferably about 0.06 to 0.2 parts by weight.

Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglucolate, 2,3-dimercapto-1-propanol and the like. The chain transfer agent may be used alone or in combination of two or more, but the total content is 0.3 parts by weight with respect to 100 parts by weight of the total amount of the monomer components. It is below the degree.

Examples of the emulsifier used in the case of emulsion polymerization include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzene sulfonate, ammonium polyoxyethylene alkyl ether sulfate, and sodium polyoxyethylene alkyl phenyl ether sulfate, and polyoxy. Examples thereof include nonionic emulsifiers such as ethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene-polyoxypropylene block polymer. These emulsifiers may be used alone or in combination of two or more.

Further, as an emulsifier into which a radically polymerizable functional group such as a propenyl group or an allyl ether group has been introduced as a reactive emulsifier, specifically, for example, Aqualon HS-10, HS-20, KH-10, BC-05. , BC-10, BC-20 (all manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Adecaria Soap SE10N (manufactured by ADEKA), and the like. The amount of the emulsifier used is preferably 5 parts by weight or less with respect to 100 parts by weight of the total amount of the monomer components.

When the (meth) acrylic polymer is produced by radiation polymerization, the monomer component can be polymerized by irradiating the monomer component with radiation such as an electron beam or ultraviolet rays (UV). Among these, ultraviolet polymerization is preferable. Hereinafter, ultraviolet polymerization, which is a preferred embodiment of radiation polymerization, will be described.

When performing ultraviolet polymerization, it is preferable to include a photopolymerization initiator in the monomer component because of the advantage that the polymerization time can be shortened. Therefore, when performing ultraviolet polymerization, for example, a monomer component containing a monofunctional monomer component containing the alkyl (meth) acrylates (A) and (B) and / or a partial polymer of the monomer component, an ultraviolet absorber, and an ultraviolet absorber, and It is preferably formed by ultraviolet polymerization of an ultraviolet curable acrylic pressure-sensitive adhesive composition containing a photopolymerization initiator. As the pressure-sensitive adhesive layer formed by UV-polymerizing the ultraviolet-curable acrylic pressure-sensitive adhesive composition, a thick pressure-sensitive adhesive layer having a thickness of 150 μm or more can be formed, and a pressure-sensitive adhesive layer having a wide thickness can be formed. preferable.

The photopolymerization initiator is not particularly limited, but preferably contains a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more. When the pressure-sensitive adhesive composition contains an ultraviolet absorber, when the ultraviolet polymerization is carried out, the ultraviolet absorber absorbs the ultraviolet rays and the polymerization cannot be sufficiently performed. However, the photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more is preferable because it can sufficiently polymerize even though it contains an ultraviolet absorber.

Examples of the photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more include bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Irgacure819, manufactured by BASF), 2,4,6-trimethylbenzoyl-. Examples thereof include diphenyl-phosphine oxide (LUCIRIN TPO, manufactured by BASF).

The photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more may be used alone or in combination of two or more.

The amount of the photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more is not particularly limited, but is preferably smaller than the amount of the ultraviolet absorber described later, (meth). It is preferably 2 parts by weight or less, more preferably 0.005 to 1 part by weight, preferably 0.01 to 1 part by weight, and 0.02 with respect to 100 parts by weight of the monofunctional monomer component forming the acrylic polymer. It is preferably ~ 0.8 parts by weight, 0.05 to 0.5 parts by weight, and preferably 0.1 to 0.3 parts by weight. When the amount of the photopolymerization initiator (A) added is within the above range, ultraviolet polymerization can proceed sufficiently, which is preferable.

Further, the photopolymerization initiator may contain a photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm. The photopolymerization initiator (B) is not particularly limited as long as it generates radicals by ultraviolet rays and initiates photopolymerization and has an absorption band at a wavelength of less than 400 nm, and is usually used for photopolymerization. Any of the initiators can be preferably used. For example, benzoin ether-based photopolymerization initiator, acetophenone-based photopolymerization initiator, α-ketol-based photopolymerization initiator, photoactive oxime-based photopolymerization initiator, benzoin-based photopolymerization initiator, benzyl-based photopolymerization initiator, benzophenone. A system photopolymerization initiator, a ketal-based photopolymerization initiator, a thioxanthone-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, and the like can be used.

Specifically, examples of the benzoin ether-based photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and 2,2-dimethoxy-1,2-diphenylethane-. 1-one, anisole methyl ether and the like can be mentioned.

Examples of the acetophenone-based photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenylketone, 4-phenoxydichloroacetophenone, and 4-t-butyldichloroacetophenone. And so on.

Examples of the α-ketol-based photopolymerization initiator include 2-methyl-2-hydroxypropiophenone and 1- [4- (2-hydroxyethyl) phenyl] -2-hydroxy-2-methylpropan-1-one. Can be mentioned.

Examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,2-propanedione-2- (O-ethoxycarbonyl) -oxime.

Examples of the benzoin-based photopolymerization initiator include benzoin and the like.

Examples of the benzyl-based photopolymerization initiator include benzyl and the like.

Benzophenone-based photopolymerization initiators include, for example, benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexylphenylketone and the like.

The ketal-based photopolymerization initiator includes benzyldimethyl ketal and the like.

Examples of the thioxanthone-based photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4. -Includes diisopropylthioxanthone, dodecylthioxanthone, etc.

Acylphosphine oxide-based photopolymerization initiators include, for example, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide and the like.

The photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm can be used alone or in combination of two or more. The photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm can be added within a range that does not impair the effects of the present invention, but the amount of the photopolymerization initiator (B) added is monofunctional to form a (meth) acrylic polymer. It is preferably about 0.005 to 0.5 parts by weight, and more preferably about 0.02 to 0.2 parts by weight with respect to 100 parts by weight of the sex monomer component.

In the present invention, when the monomer component is subjected to ultraviolet polymerization, a photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm is first added to the monomer component, and the monomer component is irradiated with ultraviolet rays to partially polymerize. It is preferable to add a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more and an ultraviolet absorber to the partial polymer (prepolymer composition) of the monomer component to perform ultraviolet polymerization. When the photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more is added to the partial polymer (prepolymer composition) of the monomer component partially polymerized by irradiation with ultraviolet rays, the photopolymerization is started. It is preferable to add the agent after dissolving it in the monomer.

The weight average molecular weight of the (meth) acrylic polymer of the present invention is preferably 400,000 to 3 million, more preferably 600,000 to 2.5 million. By setting the weight average molecular weight to more than 400,000, the durability of the pressure-sensitive adhesive layer can be satisfied, and the cohesive force of the pressure-sensitive adhesive layer can be suppressed to suppress the formation of adhesive residue. On the other hand, when the weight average molecular weight is larger than 3 million, the adhesiveness and adhesive strength tend to decrease. Further, the adhesive may become too viscous in a solution system, making coating difficult. The weight average molecular weight is a value calculated by GPC (gel permeation chromatography) and converted to polystyrene. It is difficult to measure the molecular weight of the (meth) acrylic polymer obtained by radiation polymerization.

<Measurement of weight average molecular weight>
The weight average molecular weight of the obtained (meth) acrylic polymer was measured by GPC (gel permeation chromatography). As a sample, a filtrate obtained by dissolving the sample in tetrahydrofuran to prepare a 0.1% by weight solution, allowing it to stand overnight, and then filtering it with a 0.45 μm membrane filter was used.
-Analyzer: HLC-8120GPC manufactured by Tosoh Corporation
-Column: Made by Tosoh Co., Ltd .: GM7000HXL + GMHXL + GMHXL
-Column size: 7.8 mm φ x 30 cm each, 90 cm in total
-Eluent: tetrahydrofuran (concentration 0.1% by weight)
・ Flow rate: 0.8 ml / min
・ Inlet pressure: 1.6 MPa
・ Detector: Differential refractometer (RI)
-Column temperature: 40 ° C
・ Injection amount: 100 μl
・ Eluent: Tetrahydrofuran ・ Detector: Differential refractometer ・ Standard sample: Polystyrene

(2) Ultraviolet absorber The ultraviolet absorber is not particularly limited, and for example, a triazine-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, an oxybenzophenone-based ultraviolet absorber, and a salicylate-based ultraviolet ray. Examples include an absorbent, a cyanoacrylate-based ultraviolet absorber, and the like, and these can be used alone or in combination of two or more. Among these, triazine-based UV absorbers and benzotriazole-based UV absorbers are preferable, triazine-based UV absorbers having two or less hydroxyl groups in one molecule, and benzo having one benzotriazole skeleton in one molecule. At least one type of UV absorber selected from the group consisting of triazole-based UV absorbers has good solubility in the monomer used for forming the acrylic pressure-sensitive adhesive composition, and has a wavelength of around 380 nm. It is preferable because it has a high ability to absorb ultraviolet rays.

Specific examples of the triazine-based ultraviolet absorber having two or less hydroxyl groups in one molecule include 2,4-bis- [{4- (4-ethylhexyloxy) -4-hydroxy} -phenyl] -6. -(4-methoxyphenyl) -1,3,5-triazine (Tinosorb S, manufactured by BASF), 2,4-bis [2-hydroxy-4-butoxyphenyl] -6- (2,4-dibutoxyphenyl) -1,3,5-triazine (TINUVIN 460, manufactured by BASF), 2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine-2-yl) -5-hydroxyphenyl Reaction product with [(C10-C16 (mainly C12-C13) alkyloxy) methyl] oxylane (TINUVIN400, manufactured by BASF), 2- [4,6-bis (2,4-dimethylphenyl) -1,3 , 5-Triazine-2-yl] -5- [3- (dodecyloxy) -2-hydroxypropoxy] phenol), 2- (2,4-dihydroxyphenyl) -4,6-bis- (2,4-) Reaction product of dimethylphenyl) -1,3,5-triazine and (2-ethylhexyl) -glycidate ester (TINUVIN405, manufactured by BASF), 2- (4,6-diphenyl-1,3,5-triazine-2) -Il) -5-[(Hexyl) oxy] -phenol (TINUVIN1577, manufactured by BASF), 2- (4,6-diphenyl-1,3,5-triazine-2-yl) -5- [2- (2- (2-) Ethylhexanoyloxy) ethoxy] -phenol (ADK STAB LA46, manufactured by ADEKA), 2- (2-hydroxy-4- [1-octyloxycarbonylethoxy] phenyl) -4,6-bis (4-phenylphenyl)- Examples thereof include 1,3,5-triazine (TINUVIN479, manufactured by BASF).

Further, as a benzotriazole-based ultraviolet absorber having one benzotriazole skeleton in one molecule, 2- (2H-benzotriazole-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-Tetramethylbutyl) phenol (TINUVIN 928, manufactured by BASF), 2- (2-hydroxy-5-tert-butylphenyl) -2H-benzotriazole (TINUVIN PS, manufactured by BASF), benzene Ester compounds (TINUVIN384-2, BASF) of propanoic acid and 3- (2H-benzotriazole-2-yl) -5- (1,1-dimethylethyl) -4-hydroxy (C7-9 side chain and linear alkyl) , 2- (2H-benzotriazole-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol (TINUVIN900, manufactured by BASF), 2- (2H-benzotriazole-2-yl) ) -6- (1-Methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol (TINUVIN928, manufactured by BASF), methyl-3- (3- (2H-benzotriazole) -2-yl) -5-t-butyl-4-hydroxyphenyl) propionate / polyethylene glycol 300 reaction product (TINUVIN1130, manufactured by BASF), 2- (2H-benzotriazole-2-yl) -p-cresol ( TINUVIN P, manufactured by BASF), 2 (2H-benzotriazole-2-yl) -4-6-bis (1-methyl-1-phenylethyl) phenol (TINUVIN234, manufactured by BASF), 2- [5-chloro (2H) ) -Benzotriazole-2-yl] -4-methyl-6- (tert-butyl) phenol (TINUVIN326, manufactured by BASF), 2- (2H-benzotriazole-2-yl) -4,6-di-tert- Pentylphenol (TINUVIN328, manufactured by BASF), 2- (2H-benzotriazole-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol (TINUVIN329, manufactured by BASF), methyl3- (3) -(2H-benzotriazole-2-yl) -5-tert-butyl-4-hydroxyphenyl) reaction product of propionate and polyethylene glycol 300 (TINUVIN213, manufactured by BASF), 2- (2H-benzotriazole-2-) Il) -6-dodecyl-4-methylpheno Lu (TINUVIN571, manufactured by BASF), 2- [2-Hydroxy-3- (3,4,5,6-tetrahydrophthalimide-methyl) -5-methylphenyl] benzotriazole (Sumisorb250, manufactured by Sumitomo Chemical Co., Ltd.) And so on.

Examples of the benzophenone-based ultraviolet absorber (benzophenone-based compound) and oxybenzophenone-based ultraviolet absorber (oxybenzophenone-based compound) include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, and 2-hydroxy. -4-methoxybenzophenone-5-sulfonic acid (anhydrous and trihydrate), 2-hydroxy-4-octyloxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 4-benzyloxy-2-hydroxybenzophenone, 2, Examples thereof include 2', 4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4-dimethoxybenzophenone and the like.

Examples of the salicylate ester-based ultraviolet absorber (salicylic acid ester-based compound) include phenyl-2-acryloyloxybenzoate, phenyl-2-acryloyloxy-3-methylbenzoate, and phenyl-2-acryloyloxy. -4-Methylbenzoate, phenyl-2-acryloyloxy-5-methylbenzoate, phenyl-2-acryloyloxy-3-methoxybenzoate, phenyl-2-hydroxybenzoate, phenyl-2-hydroxy -3-Methylbenzoate, phenyl-2-hydroxy-4methylbenzoate, phenyl-2-hydroxy-5-methylbenzoate, phenyl2-hydroxy-3-methoxybenzoate, 2,4-di-tert -Butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate (TINUVIN120, manufactured by BASF) and the like can be mentioned.

Examples of the cyanoacrylate-based ultraviolet absorber (cyanoacrylate-based compound) include alkyl-2-cyanoacrylate, cycloalkyl-2-cyanoacrylate, alkoxyalkyl-2-cyanoacrylate, alkenyl-2-cyanoacrylate, and alkynyl-. 2-Cyanoacrylate and the like can be mentioned.

The maximum absorption wavelength of the absorption spectrum of the ultraviolet absorber is preferably in the wavelength region of 300 to 400 nm, and more preferably in the wavelength region of 320 to 380 nm. The method for measuring the maximum absorption wavelength is the same as the method for measuring the dye-based compound described later.

The ultraviolet absorber may be used alone or in combination of two or more, but the content as a whole is a monofunctional monomer component forming a (meth) acrylic polymer. With respect to 100 parts by weight, it is preferably about 0.1 to 5 parts by weight, preferably 0.2 to 4 parts by weight, preferably 0.3 to 3.5 parts by weight, and further. More preferably, it is about 0.5 to 3 parts by weight. By setting the amount of the ultraviolet absorber added within the above range, the ultraviolet absorbing function of the pressure-sensitive adhesive layer can be sufficiently exhibited, and in the case of ultraviolet polymerization, it does not interfere with the polymerization, which is preferable.

(3) Dye Compound Further, the pressure-sensitive adhesive composition of the present invention can contain a dye compound existing in a wavelength region in which the maximum absorption wavelength of the absorption spectrum is 380 to 430 nm. Here, the maximum absorption wavelength means the absorption maximum wavelength showing the maximum absorbance among a plurality of absorption maximums in the spectral absorption spectrum in the wavelength region of 300 to 460 nm. ..

The dye compound used in the present invention is not particularly limited as long as it is a compound having a maximum absorption wavelength of the absorption spectrum in the wavelength region of 380 to 430 nm. The maximum absorption wavelength of the absorption spectrum of the dye compound is more preferably present in the wavelength region of 380 to 420 nm. In the present invention, by using such a dye compound in combination with the ultraviolet absorber, it is possible to sufficiently absorb light in a region (wavelength 380 nm to 430 nm) that does not affect the light emission of the organic EL element, and The light emitting region (longer wavelength side than 430 nm) of the organic EL element can be sufficiently transmitted, and as a result, deterioration of the organic EL element due to external light can be suppressed. The dye compound is not particularly limited as long as it has the wavelength characteristics, but a material that does not have fluorescence and phosphorescence performance (photoluminescence) that does not impair the displayability of the organic EL element is preferable.

The full width at half maximum of the dye compound is not particularly limited, but is preferably 80 nm or less, more preferably 5 to 70 nm, and even more preferably 10 to 60 nm. When the half-value width of the dye compound is within the above range, it is possible to control the light in the region that does not affect the light emission of the organic EL element to be sufficiently transmitted while the light on the wavelength side longer than 430 nm is sufficiently transmitted. Therefore, it is preferable. The half-value width is measured by the method described below.
<Measurement method of half width>
The full width at half maximum of the dye compound was measured from the transmitted absorption spectrum of the solution of the dye compound using an ultraviolet-visible spectrophotometer (U-4100, manufactured by Hitachi High-Tech Science Co., Ltd.) under the following conditions. From the spectroscopic spectrum measured by adjusting the concentration so that the absorbance of the maximum absorption wavelength is 1.0, the wavelength interval (full width at half maximum) between two points that is 50% of the peak value was defined as the half width of the dye compound. ..
(Measurement condition)
Solvent: Toluene or chloroform Cell: Quartz cell Optical path length: 10 mm

The dye compound may be any compound having a maximum absorption wavelength in the absorption spectrum in the wavelength region of 380 to 430 nm, and its structure and the like are not particularly limited. Examples of the dye compound include organic dye compounds and inorganic dye compounds. Among these, organic dyes are used from the viewpoint of maintaining dispersibility and transparency in resin components such as base polymers. Compounds are preferred.

Examples of the organic dye compound include azomethine-based compounds, indol-based compounds, silicic acid-based compounds, merocyanine-based compounds, pyrimidine-based compounds, and porphyrin-based compounds.

As the organic dye compound, a commercially available compound can be preferably used. Specifically, as the indole compound, BONASORB UA3911 (trade name, maximum absorption wavelength of absorption spectrum: 398 nm, half price width: 48 nm, manufactured by Orient Chemical Industry Co., Ltd., BONASORB UA3912 (trade name, maximum absorption wavelength of absorption spectrum: 386 nm, half price width: 53 nm, manufactured by Orient Chemical Industry Co., Ltd.), SOM -5-0106 (trade name, maximum absorption wavelength of absorption spectrum: 416 nm, half price width: 50 nm, manufactured by Orient Chemical Industry Co., Ltd.), as a porphyrin compound, FDB-001 (trade name, maximum absorption wavelength of absorption spectrum) : 420 nm, half price width: 14 nm, manufactured by Yamada Chemical Industry Co., Ltd.) and the like.

The dye compound may be used alone or in combination of two or more, but the content as a whole is the monofunctional monomer component 100 forming the (meth) acrylic polymer. It is preferably about 0.01 to 10 parts by weight, more preferably about 0.02 to 5 parts by weight, based on parts by weight. By setting the addition amount of the dye compound within the above range, it is possible to sufficiently absorb light in a region that does not affect the light emission of the organic EL element, and by using the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition, This is preferable because deterioration of the organic EL element can be suppressed.

(4) Silane Coupling Agent Further, the pressure-sensitive adhesive composition of the present invention may contain a silane coupling agent. The blending amount of the silane coupling agent is preferably 3 parts by weight or less, preferably 1 part by weight or less, and 0 parts by weight, based on 100 parts by weight of the monofunctional monomer component forming the (meth) acrylic polymer. 0.01 to 1 part by weight is more preferable, and 0.02 to 0.6 parts by weight is further preferable.

Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2- (3,4 epoxycyclohexyl). Epyl group-containing silane coupling agent such as ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1, Amino group-containing silane coupling agents such as 3-dimethylbutylidene) propylamine and N-phenyl-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane and the like ( Meta) Examples thereof include acrylic group-containing silane coupling agents and isocyanate group-containing silane coupling agents such as 3-isocyanuppropyltriethoxysilane.

(5) Cross-linking agent The pressure-sensitive adhesive composition of the present invention may contain a cross-linking agent. Examples of the cross-linking agent include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, silicone-based cross-linking agents, oxazoline-based cross-linking agents, aziridine-based cross-linking agents, silane-based cross-linking agents, alkyl etherified melamine-based cross-linking agents, metal chelate-based cross-linking agents, and excess Includes cross-linking agents such as oxides. The cross-linking agent may be used alone or in combination of two or more. Among these, isocyanate-based cross-linking agents are preferably used.

The above-mentioned cross-linking agent may be used alone or in combination of two or more, but the content as a whole is a monofunctional monomer forming a (meth) acrylic polymer. It is preferably 5 parts by weight or less, more preferably 0.01 to 5 parts by weight, further preferably 0.01 to 4 parts by weight, and 0.02 to 3 parts by weight with respect to 100 parts by weight of the component. Especially preferable.

The isocyanate-based cross-linking agent refers to a compound having two or more isocyanate groups (including an isocyanate regenerated functional group in which the isocyanate group is temporarily protected by a blocking agent or quantification) in one molecule. Examples of the isocyanate-based cross-linking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, aliphatic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate.

More specifically, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate, 2,4-tolylene diisocyanate, Aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, polymethylene polyphenyl isocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) ), Trimethylol propane / hexamethylene diisocyanate trimeric adduct (trade name: Coronate HL, manufactured by Nippon Polyurethane Industry Co., Ltd.), isocyanurate of hexamethylene diisocyanate (trade name: Coronate HX, Nippon Polyurethane Industry Co., Ltd.) Isocyanate adduct such as (manufactured by), trimethylylene propane adduct of xylylene diisocyanate (trade name: D110N, manufactured by Mitsui Chemicals, Inc.), trimethylolpropane adduct of hexamethylene diisocyanate (trade name: D160N, manufactured by Mitsui Chemicals, Inc.) ); Polyether polyisocyanate, polyester polyisocyanate, additions of these to various polyols, polyisocyanate polyfunctionalized by isocyanurate bond, burette bond, allophanate bond and the like.

(6) Antioxidant An antioxidant can be added to the pressure-sensitive adhesive composition of the present invention. When the pressure-sensitive adhesive composition contains an ultraviolet absorber, an antioxidant is added to the pressure-sensitive adhesive composition to prevent oxidative deterioration of the pressure-sensitive adhesive after a high-temperature test or a long-term UV light resistance test. Stabilization of optical characteristics such as suppression and suppression of yellowing can be expected.

Examples of the antioxidant include phenol-based, phosphorus-based, sulfur-based and amine-based antioxidants, and at least one selected from these is used. Among these, phenolic antioxidants are preferable, and hindered phenolic antioxidants are particularly preferable.

Specific examples of the phenolic antioxidant include 2,6-di-t-butyl-p-cresol, 2,6-di-t-butyl-4-ethylphenol, and 2,6-, as monocyclic phenol compounds. Dicyclohexyl-4-methylphenol, 2,6-diisopropyl-4-ethylphenol, 2,6-di-t-amyl-4-methylphenol, 2,6-di-t-octyl-4-n-propylphenol, 2,6-Dicyclohexyl-4-n-octylphenol, 2-isopropyl-4-methyl-6-t-butylphenol, 2-t-butyl-4-ethyl-6-t-octylphenol, 2-isobutyl-4-ethyl- 6-t-hexylphenol, 2-cyclohexyl-4-n-butyl-6-isopropylphenol, styrene mixed cresol, DL-α-tocopherol, stearyl β- (3,5-di-t-butyl-4-hydroxy) As a bicyclic phenol compound such as phenyl) propionate, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 4, 4'-thiobis (3-methyl-6-t-butylphenol), 2,2'-thiobis (4-methyl-6-t-butylphenol), 4,4'-methylenebis (2,6-di-t-butylphenol) ), 2,2'-Methylenebis [6- (1-methylcyclohexyl) -p-cresol], 2,2'-Etilidenebis (4,6-di-t-butylphenol), 2,2'-Butylidenebis (2) -T-Butyl-4-methylphenol), 3,6-dioxaoctamethylenebis [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate], triethylene glycolbis [3-( 3-t-Butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2 ´-thiodiethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] and the like as a tricyclic phenol compound, 1,1,3-tris (2-methyl-4-hydroxy) -5-t-Butylphenyl) butane, 1,3,5-tris (2,6-dimethyl-3-hydroxy-4-t-butylbenzyl) isocyanurate, 1,3,5-tris [(3,5) -Di-t-Butyl-4-hi Droxyphenyl) propionyloxyethyl] isocyanurate, tris (4-t-butyl-2,6-dimethyl-3-hydroxybenzyl) isocyanurate, 1,3,5-trimethyl-2,4,6-tris (3) , 5-Di-t-butyl-4-hydroxybenzyl) benzene and the like as tetracyclic phenol compounds, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane and the like. As phosphorus-containing phenol compounds, bis (ethyl 3,5-di-t-butyl-4-hydroxybenzylphosphonate) calcium, bis (ethyl 3,5-di-t-butyl-4-hydroxybenzylphosphonate) Benzyl and the like can be mentioned.

The content of the antioxidant in the pressure-sensitive adhesive composition of the present invention is usually 100 parts by weight of the (meth) acrylic polymer, and the content of the antioxidant is in the range of 0.2 to 3 parts by weight. It is preferable to do so.

(7) Other Additives In addition to the above-mentioned components, the pressure-sensitive adhesive composition of the present invention may contain appropriate additives depending on the intended use. For example, a tackifier (for example, a solid, semi-solid, or liquid material at room temperature made of a rosin derivative resin, a polyterpene resin, a petroleum resin, an oil-soluble phenol resin, etc.); a filler such as a hollow glass balloon; a plasticizer; an aging Inhibitors; light stabilizers (HALS) and the like can be mentioned. Furthermore, it is preferable to contain a rust preventive (benzotriazole-based compound, etc.) for the purpose of suppressing corrosion of the conductive metal, the routing wiring, and the like. These additives are preferably contained in a range of 1 part by weight or less with respect to 100 parts by weight of the monofunctional monomer component.

In the present invention, the pressure-sensitive adhesive composition is preferably adjusted to have a viscosity suitable for work such as coating on a substrate. The viscosity of the pressure-sensitive adhesive composition is adjusted, for example, by adding various polymers such as a thickening additive, a polyfunctional monomer, or the like, or by partially polymerizing the monomer components in the pressure-sensitive adhesive composition. The partial polymerization may be carried out before or after the addition of various polymers such as a thickening additive or a polyfunctional monomer. Since the viscosity of the pressure-sensitive adhesive composition changes depending on the amount of additives and the like, the polymerization rate when the monomer components in the pressure-sensitive adhesive composition are partially polymerized cannot be uniquely determined, but as a guide, it is about 20% or less. It is preferably about 3 to 20%, more preferably about 5 to 15%. If it exceeds 20%, the viscosity becomes too high, and it becomes difficult to apply it to the substrate.

2. 2. Adhesive layer for organic EL display device The pressure-sensitive adhesive layer for organic EL display device of the present invention is formed from the pressure-sensitive adhesive composition for organic EL display device.

The thickness of the pressure-sensitive adhesive layer of the present invention is preferably 12 μm or more, more preferably 50 μm or more, and further preferably 100 μm or more, from the viewpoint of ensuring the function of absorbing light having a wavelength of less than 430 nm. It is preferably 150 μm or more, and particularly preferably 150 μm or more. The upper limit of the thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 1 mm or less, more preferably 300 μm or less, and further preferably 250 μm or less. If the thickness of the pressure-sensitive adhesive layer exceeds 1 mm, it becomes difficult for ultraviolet rays to pass through, it takes time to polymerize the monomer components, and there are problems with processability, winding in the process, and transportability, resulting in poor productivity. Therefore, it is not preferable.

Further, in the pressure-sensitive adhesive layer of the present invention, the peak value (Tg) of tan δ when the dynamic viscoelasticity is measured at a frequency of 1 Hz is −20 ° C. to −5 ° C., preferably −19 ° C. to −6 ° C., and further. It is preferably −18 ° C. to −7 ° C. When the Tg is higher than −5 ° C., the pressure-sensitive adhesive layer is hard and lacks flexibility, so that the peeling resistance at the time of a drop impact cannot be satisfied. On the other hand, when the Tg is lower than −20 ° C., it becomes too soft and it becomes difficult to secure the elastic modulus at a high temperature.

Further, since the magnitude of tan δ in the low temperature region can be approximated to the property of losing (dissipating) the energy of the drop impact, which is a deformation in the high speed region, the pressure-sensitive adhesive layer of the present invention has tan δ at the peak value. The value of is adjusted to the range of 1.6 or more and 2.6 or less. The value of tan δ at the peak value is preferably in the range of 1.8 to 2.6, and more preferably in the range of 2.0 to 2.6.

The peak value (Tg) of tan δ is represented by the ratio (G ″ / G ′) of the loss elastic modulus G ″ and the storage elastic modulus G ′, and as described above, the peak value (Tg) is in the region of −5 ° C. or lower. Tg), and when the peak value (Tg) is high (that is, the loss elastic modulus G ″ is large), the property of dissipating the impact is enhanced, so that the adhesive has high drop impact resistance. It is considered that the agent layer is obtained.

The pressure-sensitive adhesive layer of the present invention has a transmittance of 10% or less at a wavelength of 380 nm and a transmittance of 85% or more at a wavelength of 450 nm.

The transmittance of the pressure-sensitive adhesive layer at a wavelength of 380 nm is preferably 5% or less, and more preferably 2% or less. When the transmittance of the pressure-sensitive adhesive layer is within the above range, light in a region that does not affect the light emission of the organic EL element can be sufficiently absorbed, and deterioration of the organic EL element can be suppressed.

The transmittance of the pressure-sensitive adhesive layer at a wavelength of 450 nm is preferably 88% or more, preferably 89% or more, and more preferably 90% or more. When the transmittance of the pressure-sensitive adhesive layer is within the above range, light can be sufficiently transmitted in the light emitting region (longer wavelength side than 430 nm) of the organic EL element, and the organic EL using the pressure-sensitive adhesive layer can be sufficiently transmitted. The display device can emit sufficient light.

Further, since the pressure-sensitive adhesive layer of the present invention has the transmittance, it can sufficiently absorb light in a region that does not affect the light emission of the organic EL element, and is longer than the light emitting region (longer than 430 nm) of the organic EL element. (Wavelength side) can be sufficiently transmitted, and deterioration of the organic EL element due to external light can be suppressed.

Further, the pressure-sensitive adhesive layer of the present invention has a total light transmittance of 85% or more. The total light transmittance is preferably 88% or more, preferably 89% or more, and further preferably 90% or more. The haze is 0 to 1%, preferably 0.8% or less, and more preferably 0.6% or less. When the total light transmittance and haze are within the above ranges, the pressure-sensitive adhesive layer has high transparency.
Regardless of the thickness of the pressure-sensitive adhesive layer of the present invention, the total light transmittance and haze preferably satisfy the above range, and the thickness of the pressure-sensitive adhesive layer preferably satisfies the above range of 12 to 1 mm, and further 12 μm. It is particularly preferable to satisfy the above range in the range of ~ 250 μm.

Further, the pressure-sensitive adhesive layer of the present invention is designed to satisfy low dielectric properties that do not adversely affect the sensor sensitivity. For example, the pressure-sensitive adhesive layer is preferably designed to have a relative permittivity of 4.2 or less at a frequency of 100 kHz. In particular, the relative permittivity is preferably 4.1 or less, and more preferably 4.0 or less. When the relative permittivity is 4.0 or less, it is also preferable for reducing the influence of driving noise of the organic EL panel. The pressure-sensitive adhesive layer is preferably controlled in the range of more than 3.5 to 4.0 from the viewpoint of achieving both low dielectric properties and high drop impact resistance, and when high drop impact resistance is emphasized, the pressure-sensitive adhesive layer is preferably controlled. It is preferable to control the control in the range of 3.6 to 4.0, more preferably in the range of 3.8 to 4.0.

The gel fraction of the pressure-sensitive adhesive layer of the present invention is not particularly limited, but is preferably 40 to 90% by weight. The gel fraction is preferably 40% by weight or more, more preferably 50% by weight or more, and further preferably 60% by weight or more from the viewpoint of ensuring processability, handleability, and cohesive force. More preferred. On the other hand, the gel fraction is preferably 85% by weight or less, more preferably 80% by weight or less, and further preferably 75% by weight or less from the viewpoint of energy loss and stress relaxation. .. By adjusting the gel fraction of the pressure-sensitive adhesive layer within the above range, the cohesive force of the pressure-sensitive adhesive layer can be ensured, which is preferable in terms of workability and handleability.

Further, the pressure-sensitive adhesive layer of the present invention should have a 180-degree peel adhesive force (peeling speed 300 mm / min) of 7 N / 20 mm or more with respect to non-alkali glass to prevent the film from peeling in the reliability test and at the time of a drop impact. It is preferable from the viewpoint of preventing peeling. The adhesive strength is preferably 8N / 20mm or more, and more preferably 10N / 20mm or more. On the other hand, the adhesive force is preferably 30 N / 20 mm or less, more preferably 28 N / 20 mm or less, from the viewpoint that it adheres to the blade during processing and the processing becomes difficult, and the generated adhesive debris contaminates the process.

The method for forming the pressure-sensitive adhesive layer is not particularly limited, and the pressure-sensitive adhesive layer can be formed by a method usually used in this field. Specifically, the pressure-sensitive adhesive composition is applied to at least one surface of a base material, and a coating film formed from the pressure-sensitive adhesive composition is dried to form, or is irradiated with active energy rays such as ultraviolet rays. Can be formed.

The base material is not particularly limited, and for example, various base materials such as a release film and a transparent resin film base material, and a polarizing film described later can be preferably used as the base material. A conductive layer for the purpose of antistatic can be provided on the surface and / or the back surface where the pressure-sensitive adhesive layer of the base material is provided.

Further, the pressure-sensitive adhesive layer formed on the release film (separator) is further provided with a release film (separator) as a sheet-like material, such as a release film (separator) / adhesive layer / release film (separator). It can be used in the form of.

Examples of the constituent material of the release film include resin films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film, porous materials such as paper, cloth, and non-woven fabric, nets, foam sheets, metal foils, and laminates thereof. An appropriate thin leaf body or the like can be mentioned, but a resin film is preferably used from the viewpoint of excellent surface smoothness.

Examples of the resin film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, and ethylene. -Vinyl acetate copolymer film and the like can be mentioned.

The thickness of the release film is usually 5 to 200 μm, preferably about 5 to 100 μm. The release film may be subjected to a release and antifouling treatment with a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, silica powder, etc., as needed, as well as a coating type and a kneading type. Antistatic treatment such as vapor deposition type can also be performed. In particular, the peelability from the pressure-sensitive adhesive layer can be further enhanced by appropriately performing a peeling treatment such as a silicone treatment, a long-chain alkyl treatment, or a fluorine treatment on the surface of the release film.

The transparent resin film base material is not particularly limited, but various transparent resin films are used. The resin film is formed of a single layer film. For example, as the material, polyester resin such as polyethylene terephthalate and polyethylene naphthalate, acetate resin, polyether sulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, (meth) acrylic resin. , Polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyallylate resin, polyphenylene sulfide resin and the like. Of these, polyester-based resins, polyimide-based resins and polyether sulfone-based resins are particularly preferable.

The thickness of the film substrate is preferably 15 to 200 μm, more preferably 25 to 188 μm.

The method of applying the pressure-sensitive adhesive composition on the substrate is roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain. Any known and appropriate method such as a coat, a lip coat, and a die coater can be used, and is not particularly limited.

When the pressure-sensitive adhesive layer is formed by drying a coating film formed from the pressure-sensitive adhesive composition, the drying conditions (temperature, time) thereof are not particularly limited, and the composition of the pressure-sensitive adhesive composition, It can be appropriately set depending on the concentration and the like, and is, for example, about 60 to 170 ° C., preferably 60 to 150 ° C. for 1 to 60 minutes, preferably 2 to 30 minutes.

When the pressure-sensitive adhesive composition is an ultraviolet-curable pressure-sensitive adhesive composition and the coating film formed from the UV-curable pressure-sensitive adhesive composition is formed by irradiating the coating film with ultraviolet rays, the illuminance of the irradiated ultraviolet rays is 5 mW / Cm ² or more is preferable. If the illuminance of the ultraviolet rays is less than 5 mW / cm ² , the polymerization reaction time becomes long and the productivity may be inferior. The illuminance of the ultraviolet rays is preferably 200 mW / cm ² or less. When the illuminance of the ultraviolet rays exceeds 200 mW / cm ² , the photopolymerization initiator is rapidly consumed, so that the molecular weight of the polymer is lowered, and the holding power at a particularly high temperature may be lowered. Further, the integrated quantity of ultraviolet light ^is preferably ^{100mJ / cm 2 ~5000mJ / cm 2} .

The ultraviolet lamp used in the present invention is not particularly limited, but an LED lamp is preferable. Since the LED lamp is a lamp having a lower heat emission than other ultraviolet lamps, the temperature during the polymerization of the pressure-sensitive adhesive layer can be suppressed. Therefore, it is possible to prevent the polymer from having a low molecular weight, prevent a decrease in the cohesive force of the pressure-sensitive adhesive layer, and increase the holding power at high temperatures when the pressure-sensitive adhesive sheet is used. It is also possible to combine a plurality of ultraviolet lamps. It is also possible to intermittently irradiate ultraviolet rays to provide a light period in which ultraviolet rays are irradiated and a dark period in which ultraviolet rays are not irradiated.

In the present invention, the final polymerization rate of the monomer component in the ultraviolet curable pressure-sensitive adhesive composition is preferably 90% or more, more preferably 95% or more, still more preferably 98% or more.

In the present invention, the peak wavelength of ultraviolet rays irradiating the ultraviolet curable pressure-sensitive adhesive composition is preferably in the range of 200 to 500 nm, and more preferably in the range of 300 to 450 nm. If the peak wavelength of ultraviolet rays exceeds 500 nm, the photopolymerization initiator may not be decomposed and the polymerization reaction may not be started. Further, if the peak wavelength of ultraviolet rays is less than 200 nm, the polymer chains may be cut and the adhesive properties may be deteriorated.

Since the reaction is inhibited by oxygen in the air, in order to block oxygen, a release film or the like is formed on a coating film formed from an ultraviolet curable acrylic pressure-sensitive adhesive composition, or a photopolymerization reaction is carried out with nitrogen. It is preferable to go in an atmosphere. Examples of the release film include the above-mentioned ones. When a release film is used, the release film can be used as it is as a separator for a polarizing film with an adhesive layer.

When the ultraviolet curable pressure-sensitive adhesive composition used in the present invention contains a photopolymerization initiator (B), a monomer component containing an alkyl (meth) acrylate and the photopolymerization initiator (B) (“previous” A composition containing (sometimes referred to as an "additional polymerization initiator") is irradiated with ultraviolet rays to form a partial polymer of the monomer component, and the partial polymer of the monomer component is combined with an ultraviolet absorber and a wavelength of 400 nm or more. It is preferable to add a photopolymerization initiator (A) having an absorption band (sometimes referred to as a “post-addition polymerization initiator”) to prepare an ultraviolet curable pressure-sensitive adhesive composition. The polymerization rate of the partial polymer is preferably about 20% or less, more preferably about 3 to 20%, and even more preferably about 5 to 15%. The irradiation conditions of ultraviolet rays are as described above.

As described above, when the pressure-sensitive adhesive layer is formed from the ultraviolet-curable pressure-sensitive adhesive composition containing the photopolymerization initiator (B), the polymerization rate of the monomer component is increased by polymerizing in the above-mentioned two steps. It is possible to improve the ultraviolet absorbing function of the finally produced pressure-sensitive adhesive layer.

3. 3. Polarizing film with pressure-sensitive adhesive layer for organic EL display device The polarizing film with pressure-sensitive adhesive layer for organic EL display device of the present invention is characterized by having a polarizing film and the pressure-sensitive adhesive layer for organic EL display device.

As the pressure-sensitive adhesive layer for the organic EL display device, the above-mentioned one can be preferably used. Further, when the pressure-sensitive adhesive layer is formed on a substrate other than the polarizing film, the pressure-sensitive adhesive layer can be attached to the polarizing film and transferred. Further, the release film can be used as it is as a separator for a polarizing film with an adhesive layer, which can simplify the process.

The polarizing film is not particularly limited, and examples thereof include a polarizing element and a polarizing film having a transparent protective film on at least one surface of the polarizing element.

(1) Polarizer The polarizer is not particularly limited, and various polarizers can be used. Examples of the polarizer include a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, and an ethylene / vinyl acetate copolymer system partially saponified film, and a bicolor property of iodine or a bicolor dye. Examples thereof include a uniaxially stretched film by adsorbing a substance, a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol and a dehydrogenated product of polyvinyl chloride. Among these, a polarizer made of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 μm.

A polarizer in which a polyvinyl alcohol-based film is dyed with iodine and uniaxially stretched can be produced, for example, by dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine and stretching it to 3 to 7 times the original length. If necessary, it can be immersed in an aqueous solution of potassium iodide or the like, which may contain boric acid, zinc sulfate, zinc chloride or the like. Further, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing. In addition to being able to clean the surface of the polyvinyl alcohol film and blocking inhibitors by washing the polyvinyl alcohol film with water, it also has the effect of preventing non-uniformity such as uneven dyeing by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, stretching while dyeing, or stretching and then dyeing with iodine. It can be stretched even in an aqueous solution such as boric acid or potassium iodide or in a water bath.

Further, in the present invention, a thin polarizing element having a thickness of 10 μm or less can also be used. From the viewpoint of thinning, the thickness is preferably 1 to 7 μm. It is preferable that such a thin polarizing element has less uneven thickness, excellent visibility, excellent durability because there is little dimensional change, and the thickness of the polarizing film can be reduced.

Typical examples of the thin polarizer include Japanese Patent Application Laid-Open No. 51-06644, Japanese Patent Application Laid-Open No. 2000-338329, International Publication No. 2010/100917 Pamphlet, International Publication No. 2010/100917 Pamphlet, or Patent. Examples thereof include the thin polarizing film described in the specification of No. 4751481 and Japanese Patent Application Laid-Open No. 2012-073563. These thin polarizing films can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol-based resin (hereinafter, also referred to as PVA-based resin) layer and a resin base material for stretching in a laminated state and a step of dyeing. With this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without problems such as breakage due to stretching because it is supported by the stretching resin base material.

The thin polarizing film can be stretched at a high magnification and the polarization performance can be improved even in a manufacturing method including a step of stretching in a laminated state and a step of dyeing, and the international publication No. 2010/100917 pamphlet. , International Publication No. 2010/100917, or those obtained by a production method including a step of stretching in an aqueous boric acid solution as described in Japanese Patent Application Laid-Open No. 4751481 and Japanese Patent Application Laid-Open No. 2012-0756363, particularly patented. It is preferably obtained by a production method including a step of auxiliary stretching in the air before stretching in an aqueous boric acid solution described in the specification of 4751481 and JP2012-0735663.

(2) Transparent protective film As the transparent protective film, those conventionally used can be appropriately used. Specifically, a transparent protective film formed of a material having excellent transparency, mechanical strength, thermal stability, moisture blocking property, isotropic property, etc. is preferable, and for example, a polyester polymer such as polyethylene terephthalate or polyethylene naphthalate is preferable. , Cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymer (AS resin), polycarbonate-based polymers and the like. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, and sulfone polymers. , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, allylate polymer, polyoxymethylene polymer, epoxy polymer, or Blends of the polymers and the like are also mentioned as examples of polymers forming the transparent protective film. The transparent protective film can also be formed as a cured layer of a thermosetting type or ultraviolet curable type resin such as acrylic type, urethane type, acrylic urethane type, epoxy type and silicone type.

The thickness of the transparent protective film can be appropriately determined, but is generally about 1 to 500 μm in terms of workability such as strength and handleability, and thin film property.

It is preferable that the polarizer and the transparent protective film are brought into close contact with each other via a water-based adhesive or the like. Examples of the water-based adhesive include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based adhesives, water-based polyurethanes, and water-based polyesters. In addition to the above, examples of the adhesive between the polarizer and the transparent protective film include an ultraviolet curable adhesive and an electron beam curable adhesive. The electron beam curable polarizing film adhesive exhibits suitable adhesiveness to the above-mentioned various visible side transparent protective films. Further, the adhesive used in the present invention may contain a metal compound filler.

The surface of the transparent protective film to which the polarizer is not adhered may be subjected to a hard coat layer, antireflection treatment, anti-sticking treatment, or treatment for the purpose of diffusion or anti-glare.

Further, as the transparent protective film, any film having a phase difference and capable of functioning as an optical compensation layer can be used. When a transparent protective film having a phase difference is used, the phase difference characteristic can be appropriately adjusted to a value required for optical compensation. As such a retardation film, a stretched film can be preferably used. In the retardation film, when the refractive index in the slow axis direction is nx, the refractive index in the in-plane phase advance axis direction is ny, and the refractive index in the thickness direction is nz, nx = ny> nz, nx> ny. Those that satisfy the relationship of> nz, nz> ny = nz, nz> nz> ny, nz = nz> ny, nz> nz> ny, nz> nx = ny are selected and used according to various uses. Be done. Note that nx = ny includes not only the case where nx and ny are completely the same, but also the case where nx and ny are substantially the same. Further, ny = nz includes not only the case where ny and nz are completely the same, but also the case where ny and nz are substantially the same.

When the polarizing film used in the present invention is used as a circular polarizing plate for antireflection of an organic EL display device, the retardation film has a front retardation of a transparent protective film of 1/4 wavelength (about 100 to 170 nm). It is preferably a 1/4 wavelength plate.

When a retardation film is used as the transparent protective film, one in which the transparent protective film is provided on one surface of the polarizer and the retardation film is provided on the other surface can be preferably used. Further, in that case, the place where the pressure-sensitive adhesive layer is installed is not particularly limited, and may be provided on the surface opposite to the surface of the transparent protective film in contact with the polarizing element of the retardation film. Although it may be provided on the surface opposite to the surface in contact with the organic EL element, it is preferably provided on at least one surface or both surfaces from the viewpoint of suppressing deterioration of the organic EL element.

An example of a specific configuration of the polarizing film with an adhesive layer for an organic EL display device of the present invention is shown in FIGS. 1 (a) to 1 (c). As shown in FIG. 1 (a), the pressure-sensitive adhesive layer 2 / transparent protective film 3 / polarizer 4 / retardation film 5, and as shown in FIG. 1 (b), the transparent protective film 3 / polarizer 4 / retardation film 5. Film 5 / adhesive layer 2, as shown in FIG. 1 (c), each layer is in this order, such as adhesive layer 2 / transparent protective film 3 / polarizer 4 / retardation film 5 / adhesive layer 2. A laminated polarizing film 1 with an adhesive layer for an organic EL display device can be mentioned. In FIGS. 1 (a) and 1 (b), the pressure-sensitive adhesive layer 2 is the pressure-sensitive adhesive layer for an organic EL display device of the present invention, and in FIG. 1 (c), at least one of the two pressure-sensitive adhesive layers 2 One may be the pressure-sensitive adhesive layer for the organic EL display device of the present invention, and both may be the pressure-sensitive adhesive layer for the organic EL display device of the present invention. Further, in FIG. 1, the polarizing film 6 is a one-sided protective polarizing film composed of a polarizing element 4 and a transparent protective film 3, but the present invention is not limited to this, and the polarizing element 4 and the retardation film 5 It may be both protective polarizing films having a transparent protective film in between. Further, as described above, various functional layers such as a hard coat layer can be formed on the surface of the transparent protective film 3 that is not in contact with the polarizer 4.

Further, when the retardation film is laminated on the polarizer via the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer may be the pressure-sensitive adhesive layer for an organic EL display device of the present invention. That is, the polarizing film with the pressure-sensitive adhesive layer for an organic EL display device has a first pressure-sensitive adhesive layer, a transparent protective film, a polarizer, a second pressure-sensitive adhesive layer, a retardation film, and a third pressure-sensitive adhesive layer in this order.
At least one of the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer, and the third pressure-sensitive adhesive layer may be the pressure-sensitive adhesive layer for an organic EL display device.

4. Organic EL Display Device The organic EL display device of the present invention uses at least one polarizing film with an adhesive layer for an organic EL display device of the present invention and / or an adhesive layer for an organic EL display device of the present invention. It is a feature.

As an example of a specific configuration of the organic EL display device, for example, as shown in FIGS. 2 and 3, a cover glass or a cover plastic 7 / an adhesive layer 2b / a transparent protective film 3 / a polarizer 4 / a retardation film 5 / Adhesive layer 2a / Organic EL display panel (OLED element panel) 8 (Fig. 2); Cover glass or cover plastic 7 / Adhesive layer 9 / Transparent protective film 3 / Polarizer 4 / Phase difference film 5 / Adhesive As shown in the layer 2a / organic EL display panel 8 (FIG. 3), an organic EL display device in which each layer is laminated in this order can be mentioned.

Further, as the organic EL display device, it can be used as an organic EL display device with a touch panel having a touch panel having at least one sensor film. For example, as shown in FIG. 4, cover glass or cover plastic 7 / adhesive layer 2c / sensor film 10 / adhesive layer 2b / transparent protective film 3 / polarizer 4 / retardation film 5 / adhesive layer 2a / organic As shown in the EL display panel 8 (FIG. 4); an organic EL display device in which each layer is laminated in this order can be mentioned.

At least one of the pressure-sensitive adhesive layers 2 in each of the above configurations may be the pressure-sensitive adhesive layer of the present invention, and all the pressure-sensitive adhesive layers 2 may be the pressure-sensitive adhesive layer of the present invention. In addition to the above, the organic EL display device of the present invention may include various functional layers such as a protective film and a hard coat layer. In addition, an adhesive layer and / or an adhesive layer can be appropriately used in laminating each layer. As the pressure-sensitive adhesive layer other than the pressure-sensitive adhesive layer of the present invention, a normal pressure-sensitive adhesive layer used in the present field can be appropriately used.

The pressure-sensitive adhesive layer for an organic EL display device of the present invention includes an organic EL panel, a circularly polarizing film provided in order from the visual side of the organic EL panel, and a touch panel having at least one sensor film, as shown in FIG. It is suitably applied to an organic EL display device with a touch panel. In particular, the pressure-sensitive adhesive layer for an organic EL display device of the present invention is suitable when it is provided on the visual side of the circularly polarizing film and is provided so as to be in contact with at least one sensor film forming a touch panel. Applies to. In FIG. 4, as the pressure-sensitive adhesive layer 2c and / or the pressure-sensitive adhesive layer 2b in contact with the sensor film 10, the pressure-sensitive adhesive layer for an organic EL display device of the present invention is preferably applied, and in particular, as the pressure-sensitive adhesive layer 2b. Is suitable for use. The pressure-sensitive adhesive layer 2b may be applied as a polarizing film with a pressure-sensitive adhesive layer as shown in FIG. 1A, or may be applied as a pressure-sensitive adhesive layer between the layers of the sensor film and the circularly polarizing film. ..

In addition, in FIG. 4, when two or more sensor films 10 are used, the pressure-sensitive adhesive layer for an organic EL display device of the present invention is preferably applied. For example, cover glass or cover plastic 7 / adhesive layer 2c / sensor film 10 / adhesive layer 2b'/ sensor film 10'/ adhesive layer 2b / transparent protective film 3 / polarizer 4 / retardation film 5 / adhesive In the configuration of the layer 2a / organic EL display panel 8, in addition to the pressure-sensitive adhesive layer 2c and / or the pressure-sensitive adhesive layer 2b, the pressure-sensitive adhesive layer 2b'is suitably applied as the pressure-sensitive adhesive layer for the organic EL display device of the present invention. Will be done.

The sensor film 10 in FIG. 4 is a capacitance type touch sensor (film), and is a transparent conductive film in which a transparent conductive layer is provided on a glass plate or a transparent plastic film (particularly PET film). When the pressure-sensitive adhesive layer for an organic EL display device comes into contact with the sensor film, it means that it comes into contact with the transparent conductive layer.

Examples of the transparent conductive layer include thin films of ITO film (indium tin oxide), ZnO, SnO, and CTO (cadmium oxide tin oxide). In addition, the transparent conductive layer can be formed of silver, copper, CNT (carbon nanotube) or the like. As the transparent conductive layer, a metal mesh sensor such as Ag nanowire or Ag / Cu can also be adopted. Further, in FIG. 4, the capacitance type touch panel using at least one sensor film 10 may have a routing wire formed of a thin film of copper or silver paste at the end of the sensor film.

As described above, the pressure-sensitive adhesive layer for an organic EL display device of the present invention is used as a pressure-sensitive adhesive layer used for contacting and providing at least one sensor film on the touch panel of the organic EL display device having the above configuration. In addition, it can be used not only for organic EL display devices but also as a touch panel adhesive layer used for touching and providing at least one sensor film in a touch panel.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. In addition, each part and% in each example is based on weight.

Example 1
(Preparation of acrylic pressure-sensitive adhesive composition)
7 parts by weight of 2-ethylhexyl acrylate (2EHA), 52 parts by weight of n-butyl acrylate (BA), 22 parts by weight of isostearyl acrylate (ISTA), 13 parts by weight of N-vinyl-2-pyrrolidone (NVP) and 4-hydroxybutyl 1-Hydroxycyclohexylphenylketone (trade name: Irgacure 184, having an absorption band at a wavelength of 200 to 370 nm, manufactured by BASF) as a photopolymerization initiator in a monomer mixture composed of 6 parts by weight of acrylate (4HBA). After blending 035 parts by weight and 0.035 parts by weight of 2,2-dimethoxy-1,2-diphenylethane-1-one (trade name: Irgacure 651, having an absorption band at a wavelength of 200 to 380 nm, manufactured by BASF). , A prepolymer composition (polymerization) in which a part of the above-mentioned monomer mixture was polymerized by irradiating ultraviolet rays until the viscosity (measurement condition: BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30 ° C.) became about 20 Pa · s. Rate: 9%) was obtained. Next, the prepolymer composition contains 0.05 parts by weight of hexanediol diacrylate (HDDA) and a silane coupling agent (commodity) with respect to 100 parts by weight of the monofunctional monomer component in the obtained acrylic pressure-sensitive adhesive composition. Name: KBM-403, manufactured by Shin-Etsu Chemical Industry Co., Ltd., 0.3 parts by weight, phenol-based antioxidant (trade name: IRGANOX 1010, manufactured by BASF Japan), 0.5 parts by weight, in a monomer mixture having the same ratio as above. 2,4-Bis- [{4- (4-ethylhexyloxy) -4-hydroxy} -phenyl] -6- (4-methoxyphenyl) -1,3,5-dissolved to a solid content of 10% Triazine (trade name: Monosorb S UV absorber (a), manufactured by BASF Japan) 0.8 parts by weight (solid content weight) and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (trade name) : Irgacure 819, manufactured by BASF Japan, Ltd.) An acrylic pressure-sensitive adhesive composition was obtained by adding 0.25 parts by weight and stirring.

(Formation of adhesive layer)
The acrylic pressure-sensitive adhesive composition is applied onto the release-treated film of the release film so that the thickness after forming the pressure-sensitive adhesive layer is 100 μm, and then the surface of the pressure-sensitive adhesive composition layer is coated. The release film was pasted together. Then, ultraviolet irradiation was performed under the conditions of illuminance: 6.5 mW / cm ² , light intensity: 1500 mJ / cm ² , and peak wavelength: 350 nm, and the pressure-sensitive adhesive composition layer was photo-cured to form a pressure-sensitive adhesive layer.

Examples 2-5 and Comparative Examples 1-2
In Example 1, an acrylic pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the types and amounts of each component were changed as shown in Table 1 in the preparation of the acrylic pressure-sensitive adhesive composition. .. Further, using the acrylic pressure-sensitive adhesive composition, the pressure-sensitive adhesive layer was formed in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer was changed as shown in Table 1.

(Manufacturing of polarizing film (P))
A 25 μm-thick cycloolefin polymer (COP) film was attached to the visible side of the polarizer made of a stretched polyvinyl alcohol film with a thickness of 5 μm impregnated with iodine using a polyvinyl alcohol-based adhesive, and the organic EL of the polarizer was attached. A retardation film (thickness: 56 μm, material: polycarbonate) was laminated on the surface on the display panel side using a polyvinyl alcohol-based adhesive to obtain a polarizing film (P). The degree of polarization of the polarizing film was 99.995.

(Manufacturing of polarizing film with adhesive layer)
The pressure-sensitive adhesive layer obtained in Example or Comparative Example is laminated on the visible side of the polarizing film (P) (that is, the surface of a cycloolefin polymer (COP) film having a thickness of 25 μm), and polarized light with a pressure-sensitive adhesive layer is provided. A film was formed.

The pressure-sensitive adhesive layer and the polarizing film with the pressure-sensitive adhesive layer obtained in Examples or Comparative Examples were evaluated as follows. The results are shown in Table 1.

<Tg measurement of adhesive layer by dynamic viscoelasticity>
The pressure-sensitive adhesive layers obtained in Examples or Comparative Examples were laminated to obtain a pressure-sensitive adhesive laminate layer having a thickness of about 2 mm. The pressure-sensitive adhesive laminate layer is punched into a disk shape having a diameter of 7.9 mm, sandwiched between parallel plates and fixed, and a dynamic viscoelasticity measuring device (ARES, manufactured by Leometrics) is used under the measurement conditions described below. The loss elastic modulus G'' and the storage elastic modulus G'were measured. The peak value of the ratio of loss elastic modulus to storage elastic modulus (G'' / G') = tan δ was read as Tg of the pressure-sensitive adhesive layer.
The peak value was read as the maximum value of tan δ [-] in the measurement temperature range.
-Measurement: Shear mode-Temperature range: -50 ° C to 150 ° C
・ Temperature rise rate: 5 ° C / min
・ Frequency: 1Hz
The storage elastic modulus G'(25 ° C.) is preferably 8.0 × 10 ⁴ Pa or more and 2.0 × 10 ⁵ Pa or less. The storage elastic modulus G'(80 ° C.) is preferably 3.0 × 10 ⁴ Pa or more and 1.4 × 10 ⁵ Pa or less. It is preferable that the storage elastic modulus G'(25 ° C.) satisfies 8.0 × 10 ⁴ Pa or more in order to ensure workability during punching, and 2.0 × 10 ⁵ Pa or less is satisfied. Is preferable in order to ensure the followability to the printing step of decorative printing such as cover glass. It is preferable that the storage elastic modulus G'(80 ° C.) satisfies the above 3.0 × 10 ⁴ Pa or more in order to suppress peeling of the film or the like at the time of charging in high temperature reliability, and 1.4 × 10 ⁵ Satisfying Pa or less is preferable because bubbles generated during bonding can be satisfactorily removed during the autoclave (pressure defoaming) treatment.

<Measurement of transmittance and hue of adhesive layer with dye absorber and UV absorber>
One of the release films is peeled off from the pressure-sensitive adhesive layer obtained in Examples or Comparative Examples, and slide glass (trade name: white polishing No. 1, thickness: 0.8 to 1.0 mm, total light transmittance) is transmitted. Rate: 92%, haze: 0.2%, bonded to Matsunami Glass Industry Co., Ltd. Further, the other release film is peeled off, the same slide glass is bonded, and after undergoing an autoclave treatment (50 ° C., 0.5 MPa, 15 minutes), a test piece having a layer structure of slide glass / adhesive layer / slide glass. Was produced. The prepared test piece was measured with a spectrophotometer (product name: U4100, manufactured by Hitachi High-Technologies Corporation). The transmittance in the wavelength range of 350 nm to 780 nm was measured. Table 1 shows the transmittances at a wavelength of 380 nm and a wavelength of 450 nm.

<Total light transmittance, haze>
One of the release films is peeled off from the pressure-sensitive adhesive layer obtained in Examples or Comparative Examples, and slide glass (trade name: white polishing No. 1, thickness: 0.8 to 1.0 mm, total light transmittance) is transmitted. Rate: 92%, haze: 0.2%, bonded to Matsunami Glass Industry Co., Ltd. Further, the other release film was peeled off to prepare a test piece having a layer structure of an adhesive layer / slide glass. The total light transmittance and haze value in the visible light region of the test piece were measured using a haze meter (device name: HM-150, manufactured by Murakami Color Research Institute Co., Ltd.).

<Evaluation of permittivity>
The pressure-sensitive adhesive layer (the one obtained by peeling the silicone-treated PET film from the pressure-sensitive adhesive sheet) obtained in Examples or Comparative Examples is sandwiched between a copper foil and an electrode, and the relative permittivity at a frequency of 100 kHz is measured by the following device. did. For the measurement, 3 samples were prepared, and the average of the measured values of those 3 samples was taken as the relative permittivity.
The relative permittivity of the pressure-sensitive adhesive layer at a frequency of 100 kHz was measured under the following conditions according to JIS K 6911.
Measuring method: Capacitive method (Device: Agilent Technologies 4294A Precision Impedance Analyzer)
Electrode configuration: 12.1 mmΦ, 0.5 mm thick aluminum plate Opposite electrode: 3oz copper plate Measurement environment: 23 ± 1 ° C, 52 ± 1% RH

<Measurement of gel fraction>
A predetermined amount (initial weight W1) was taken out from the pressure-sensitive adhesive layer obtained in Examples or Comparative Examples, immersed in an ethyl acetate solution, left at room temperature for 1 week, then the insoluble matter was taken out and dried by weight (first weight W1). W2) was measured and determined as follows.
Gel fraction (%) = (W2 / W1) x 100

<Adhesiveness>
A sheet piece having a length of 100 mm and a width of 20 mm was cut out from the pressure-sensitive adhesive layer obtained in Examples or Comparative Examples. Next, one of the release films of the pressure-sensitive adhesive layer was peeled off, and a PET film (trade name: Lumirror S-10, thickness: 25 μm, manufactured by Toray Industries, Inc.) was attached (lined). Next, the other release film was peeled off and crimped to a glass plate (trade name: soda lime glass # 0050, manufactured by Matsunami Glass Industry Co., Ltd.) as a test plate under a 2 kg roller and one reciprocating crimping condition. A sample composed of a test plate / adhesive layer / PET film was prepared. The obtained sample was autoclaved (50 ° C., 0.5 MPa, 15 minutes), and then 23 ° C., 50% R. et al. H. It was allowed to cool for 30 minutes in the atmosphere of. After allowing to cool, a tensile tester (device name: Autograph AG-IS, manufactured by Shimadzu Corporation) was used, and in accordance with JIS Z0237, 23 ° C., 50% R.M. H. The adhesive sheet (adhesive layer / PET film) was peeled off from the test plate under the conditions of a tensile speed of 300 mm / min and a peeling angle of 180 °, and the 180 ° peeling adhesive strength (N / 20 mm) was measured.

<Measurement method of impact adhesion strength: Pendulum type impact test Absorption energy [J]>
The impact adhesive strength was measured using a pendulum type adhesive shear impact tester based on JIS K6855 (corresponding to the international standard ISO9653). As a test piece, the base material-less double-sided pressure-sensitive adhesive layer according to each example was cut out to a size of 10 mm square, and one side of the pressure-sensitive adhesive layer was a 2.5 mm square, 1.7-thick chemically strengthened glass plate (manufactured by Corning Inc.). After laminating so as to be in the center of Gorilla 3318), the other side of the adhesive layer is pasted so as to be in the center of a 40 mm square stainless steel plate (SUS304BA), and applied for 10 seconds with a load of 5N. After pressure bonding, an autoclave treatment (50 ° C., 0.5 MPa, 15 min.) Was performed, and then the product aged at 50 ° C. for 48 hours was used.
For the impact adhesion strength, the absorbed energy [J] when the sample was fixed so that the stainless steel plate was on the lower side and a hammer was applied to the side surface of the glass plate like a pendulum was measured.
The measurement conditions were a hammer energy of 2.75 J and a hammer speed (impact speed) of 3.5 m / sec.

In Table 1,
2EHA is 2-ethylhexyl acrylate;
BA is n-butyl acrylate;
ISTA is an isostearyl acrylate;
NVP is N-vinyl-2-pyrrolidone;
IBXA is an isobornyl acrylate;
4HBA is 4-hydroxybutyl acrylate;
HEA is 2-hydroxyethyl acrylate;
HDDA is hexanediol diacrylate;
DPHA is dipentaerythritol hexaacrylate;
TMPTA is trimethylolpropane triacrylate;
The UV absorber a is 2,4-bis- [{4- (4-ethylhexyloxy) -4-hydroxy} -phenyl] -6- (4-methoxyphenyl) -1,3,5-triazine (trade name). : Tinosorb S, maximum absorption wavelength of absorption spectrum: 346 nm, manufactured by BASF Japan);
The UV absorber b is 2- (2H-benzotriazole-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol (commercial product). Name: Butyl 928, Maximum absorption wavelength of absorption spectrum: 349 nm, manufactured by BASF Japan);
The dye compound c is BONASORB UA3912 (trade name, indole compound, maximum absorption wavelength of absorption spectrum: 386 nm, half width: 53 nm, manufactured by Orient Chemical Industry Co., Ltd.);
Irg819 is a bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (trade name: Irgacure 819, manufactured by BASF Japan Ltd.);
IRGANOX 1010 is a phenolic antioxidant (trade name IRGANOX 1010 manufactured by BASF Japan Ltd.);
KBM-403 indicates a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.);

1 Polarizing film with adhesive layer for organic EL display device 2 Adhesive layer (a, b, c)
3 Transparent protective film 4 Polarizer 5 Phase difference film 6 Polarizing film 7 Cover glass or cover plastic 8 Organic EL panel 9 Adhesive layer 10 Sensor film

Claims (23)

A pressure-sensitive adhesive layer for an organic EL display device formed from a pressure-sensitive adhesive composition containing a (meth) acrylic polymer and an ultraviolet absorber.
The (meth) acrylic polymer includes an alkyl (meth) acrylate (A) having an alkyl group having 8 or less carbon atoms at the ester terminal and an alkyl (meth) acrylate (B) having an alkyl group having 12 to 24 carbon atoms at the ester terminal. ), Which was obtained by polymerizing a monomer component containing a monofunctional monomer component.
The ratio (a:% by weight) of the alkyl (meth) acrylate (A) and the ratio (b:% by weight) of the alkyl (meth) acrylate (B) to 100% by weight of the monofunctional monomer component are as follows. Satisfying (1) and equation (2)
Equation (1): 60 ≦ {(a) + (b)}
Equation (2): 2 << {(a) / (b)} ≦ 5
And the adhesive layer is
The peak value (Tg) of tan δ when the dynamic viscoelasticity is measured at a frequency of 1 Hz is -20 to -5 ° C, and the tan δ at the peak value is in the range of 1.6 or more and 2.6 or less. ,
The transmittance at a wavelength of 380 nm is 10% or less, and the transmittance at a wavelength of 450 nm is 85% or more.
An adhesive layer for an organic EL display device, characterized in that the total light transmittance is 85% or more and the haze is 1% or less. The pressure-sensitive adhesive layer for an organic EL display device according to claim 1, wherein the maximum absorption wavelength of the absorption spectrum of the ultraviolet absorber exists in a wavelength region of 300 to 400 nm. The organic EL display device according to claim 1 or 2, wherein the monofunctional monomer component further contains at least one cohesive monomer selected from a cyclic nitrogen-containing monomer and an alicyclic structure-containing monomer. Adhesive layer. The pressure-sensitive adhesive layer for an organic EL display device according to claim 3, wherein the proportion of the cohesive monomer in the monofunctional monomer component is 10 to 22% by weight. The pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 4, wherein the monofunctional monomer component further contains a hydroxyl group-containing monomer. The pressure-sensitive adhesive layer for an organic EL display device according to claim 5, wherein the ratio of the hydroxyl group-containing monomer in the monofunctional monomer component is 1.5 to 10% by weight. The organic EL display according to any one of claims 1 to 6, wherein the monomer component further contains a polyfunctional monomer in an amount of 3 parts by weight or less with respect to 100 parts by weight of the monofunctional monomer component. Adhesive layer for equipment. The organic EL display device according to any one of claims 1 to 7, wherein the pressure-sensitive adhesive composition further contains a dye compound present in a wavelength region in which the maximum absorption wavelength of the absorption spectrum is 380 to 430 nm. Adhesive layer for. The organic according to any one of claims 1 to 8, wherein the pressure-sensitive adhesive composition further contains a silane coupling agent in an amount of 3 parts by weight or less based on 100 parts by weight of the monofunctional monomer component. Adhesive layer for EL display device. The organic EL display according to any one of claims 1 to 9, wherein the pressure-sensitive adhesive composition further contains a cross-linking agent in an amount of 3 parts by weight or less based on 100 parts by weight of the monofunctional monomer component. Adhesive layer for equipment. The pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 10, wherein the pressure-sensitive adhesive composition further contains a photopolymerization initiator. The pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 11, wherein the pressure-sensitive adhesive composition further contains an antioxidant. The pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 12, wherein the relative permittivity at a frequency of 100 kHz is 4.0 or less. The pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 13, wherein the gel fraction is 40 to 90% by weight. The organic EL display device according to any one of claims 1 to 14, wherein the pressure-sensitive adhesive layer has a 180-degree peel adhesive force (peeling speed 300 mm / min) of 7 N / 20 mm or more with respect to non-alkali glass. Adhesive layer. The pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 15, further comprising a separator on at least one side. A polarizing film with an adhesive layer for an organic EL display device, which comprises a polarizing film and an adhesive layer for an organic EL display device according to any one of claims 1 to 16. The polarizing film has a transparent protective film provided on one surface of a polarizer and a retardation film on the other surface, and the pressure-sensitive adhesive layer for an organic EL display device is a polarizing film of the retardation film. The pressure-sensitive adhesive for an organic EL display device according to claim 17, wherein the adhesive is provided on the surface opposite to the surface in contact with the child and / or on the surface opposite to the surface in contact with the polarizer of the transparent protective film. Polarized film with layers. A polarizing film with a pressure-sensitive adhesive layer having a first pressure-sensitive adhesive layer, a transparent protective film, a polarizing element, a second pressure-sensitive adhesive layer, a retardation film, and a third pressure-sensitive adhesive layer in this order.
17. Claim 17, wherein at least one of the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer, and the third pressure-sensitive adhesive layer is the pressure-sensitive adhesive layer for an organic EL display device. The above-mentioned polarizing film with an adhesive layer for an organic EL display device. The polarizing film with an adhesive layer for an organic EL display device according to claim 18 or 19, wherein the retardation film is a 1/4 wave plate and the polarizing film is a circular polarizing film. At least one polarizing film with an adhesive layer for an organic EL display device according to any one of claims 1 to 15 or a polarizing film with an adhesive layer for an organic EL display device according to any one of claims 17 to 19 is used. An organic EL display device characterized by. The organic EL display device is an organic EL display device with a touch panel having an organic EL panel, a circularly polarizing film provided in order from the visual side of the organic EL panel, and a touch panel having at least one sensor film.
The pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 15 is provided on the visual side of the circularly polarizing film in contact with at least one sensor film. The organic EL display device according to claim 21. The pressure-sensitive adhesive layer for an organic EL display device according to any one of claims 1 to 16, which is used for contacting and providing at least one sensor film on the touch panel of the organic EL display device according to claim 22.

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