JP6782071B2 - Polarizing film with double-sided adhesive layer, its manufacturing method and image display device - Google Patents

Description

The present invention relates to a polarizing film with a double-sided pressure-sensitive adhesive layer having pressure-sensitive adhesive layers on both sides of the polarizing film provided on the most visible side of the polarizing film used in an image display device, and a method for producing the same. The present invention also relates to an image display device in which the polarizing film with a double-sided pressure-sensitive adhesive layer is arranged on the viewing side. Examples of the image display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), and electronic paper.

The polarizing film with a double-sided pressure-sensitive adhesive layer of the present invention has pressure-sensitive adhesive layers on both sides of the polarizing film, and the pressure-sensitive adhesive layer on the viewing side is, for example, an input such as a touch panel applied on the viewing side of an image display device. It can be suitably applied to members such as devices, cover glasses, transparent substrates such as plastic covers. On the other hand, the pressure-sensitive adhesive layer on the opposite side of the visual viewing side is applied to the display unit of the image display device. As the touch panel, it can be suitably used for a touch panel of an optical method, an ultrasonic method, a capacitance method, a resistance film method, or the like. In particular, it is suitably used for a capacitance type touch panel. The touch panel is not particularly limited, but is used, for example, in a mobile phone, a tablet computer, a personal digital assistant, or the like.

In a liquid crystal display device or the like, it is indispensable to arrange polarizing elements on both sides of the liquid crystal cell due to the image forming method, and generally, a polarizing film is attached. An adhesive is usually used to attach the polarizing film to a display unit such as a liquid crystal cell. In such a case, since there is an advantage that a drying step is not required to fix the polarizing film, the pressure-sensitive adhesive is polarized light with a pressure-sensitive adhesive layer previously provided as a pressure-sensitive adhesive layer on one side of the polarizing film. Films are commonly used. Various types of polarizing films with an adhesive layer have been proposed (Patent Documents 1 and 2). In these polarizing films with an adhesive layer, the adhesive layer side is applied to a display portion such as a liquid crystal cell.

On the other hand, on the visual side of the polarizing film, an input device such as a touch panel and a member such as a cover glass and a transparent substrate such as a plastic cover are provided. The members are also generally bonded by an adhesive layer (Patent Document 3).

Japanese Unexamined Patent Publication No. 2004-170907 Japanese Unexamined Patent Publication No. 2006-053531 JP-A-2002-348150

As in Patent Documents 1 and 2, the polarizing film with an adhesive layer provided on the most visible side of the polarizing film used in the image display device has the adhesive layer of the polarizing film with the adhesive layer bonded to the display portion. To. On the other hand, when a member such as a transparent substrate is provided on the visible side of the polarizing film with an adhesive layer (the one provided on the most visible side), the polarizing film of the polarizing film with an adhesive layer is separately provided with Patent Document 3. A pressure-sensitive adhesive sheet for an interlayer film is prepared as described above, and the pressure-sensitive adhesive sheet is bonded to the pressure-sensitive adhesive layer, and then a member such as a transparent substrate is bonded to the pressure-sensitive adhesive layer. As described above, a plurality of steps are required to further attach a member such as a transparent substrate to the polarizing film on the most visible side of the polarizing film used in the image display device.

Patent Documents 1 and 2 disclose, as the polarizing film with an adhesive layer, a polarizing film having an adhesive layer on both sides (full lamination: a polarizing film with a double-sided adhesive layer). However, when the polarizing film with the double-sided adhesive layer is attached to an adherend (a member such as a transparent substrate on the visual side and a display portion on the opposite side), air bubbles are caught at the end of the bonded surface. The workability was not sufficient and the yield was not sufficient because such factors were likely to occur. Therefore, in the polarizing film with a double-sided pressure-sensitive adhesive layer, it is required to improve workability and yield as well as simplify the process.

Further, the surface of a member such as a transparent substrate such as the cover glass has a step due to the printing ink. Therefore, when the member having the step surface and the other member are bonded by the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer absorbs the step and the pressure-sensitive adhesive layer follows the step so that there is no gap between the members. Is required. As an index of the pressure-sensitive adhesive layer related to the step, the step absorbability (%) represented by the step (μm) and the thickness (μm) of the pressure-sensitive adhesive layer: (step / thickness of the pressure-sensitive adhesive layer) × 100 In, it is mentioned that the followability is satisfied. About 20% was required for the step absorption property. In recent years, the requirement for step absorption has become as high as 30%. Generally, in order to absorb the step, it is conceivable to lower the elastic modulus of the pressure-sensitive adhesive layer to make it soft. However, if the pressure-sensitive adhesive layer is softened, the workability is poor and a lot of adhesive stains are generated, so that the handling property It was not preferable in that respect.

On the other hand, when the pressure-sensitive adhesive layer (the side to which members such as transparent substrates are bonded) of the polarizing film with the double-sided pressure-sensitive adhesive layer is hardened, the step absorption property is lowered by full lamination, and foaming is more likely to occur with reliability. It was a thing.

Therefore, the present invention is a polarizing film with a double-sided pressure-sensitive adhesive layer having pressure-sensitive adhesive layers on both sides of the polarizing film provided on the most visible side of the polarizing film used in an image display device, and has good yield and yield. An object of the present invention is to provide a polarizing film with a double-sided pressure-sensitive adhesive layer capable of satisfying step absorption, and a method for producing the same.

Another object of the present invention is to provide an image table apparatus having the polarizing film with a double-sided pressure-sensitive adhesive layer.

As a result of diligent studies to solve the above problems, the present inventors have found the following polarizing film with a double-sided pressure-sensitive adhesive layer, and have completed the present invention.

That is, the present invention is arranged on the polarizing film provided on the most visible side of the polarizing film used in the image display device, the pressure-sensitive adhesive layer A arranged on the viewing side of the polarizing film, and the opposite side of the pressure-sensitive adhesive layer A. A polarizing film with a double-sided pressure-sensitive adhesive layer having a pressure-sensitive adhesive layer B and having a separator SA _{1 on} the pressure-sensitive adhesive layer A and a separator SB on the pressure-sensitive adhesive layer B.
The pressure-sensitive adhesive layer A has a storage elastic modulus at 23 ° C. of 0.02 to 0.3 MPa.
The polarizing film with a double-sided pressure-sensitive adhesive layer is a rectangular object cut out of 300 mm in the absorption axis direction and 250 mm in the direction perpendicular to the absorption axis of the polarizing film so that the surface having a convex curl is on the lower side. Curl amount measured by placing it on a horizontal plane (however, the curl amount measured by placing it on a horizontal plane so that the side of the separator SB is on the lower side is +, and the curl amount measured by placing it on the horizontal plane is +, and the horizontal plane is such that the side of the separator SA ₁ is on the lower side. A polarizing film with a double-sided pressure-sensitive adhesive layer, characterized in that the amount of curl measured on the top is −10 mm to +60 mm).

In the polarizing film with a double-sided pressure-sensitive adhesive layer, the curl amount is preferably +2 mm to +30 mm.

In the polarizing film with a double-sided pressure-sensitive adhesive layer, the separator SA ₁ preferably has a thickness of 50 μm or more, and the separator SB preferably has a thickness of 30 to 55 μm.

In the polarizing film with double-sided pressure-sensitive adhesive layer, the peel force a ₁ of the separator SA ₁ is preferably higher than the release force b of the separator SB.

The present invention is a method for producing a polarizing film with a double-sided pressure-sensitive adhesive layer.
A polarizing film with a one-sided pressure-sensitive adhesive layer B having a polarizing film and a pressure-sensitive adhesive layer B provided on the most visible side of the polarizing film used in an image display device and having a separator SB on the pressure-sensitive adhesive layer B.
A pressure-sensitive adhesive layer A with a one-sided separator having a pressure-sensitive adhesive layer A having a storage elastic modulus of 0.02 to 0.3 MPa at 23 ° C. on the separator SA ₁ .
The roll-toe so that the pressure-sensitive adhesive layer A of the pressure-sensitive adhesive layer A with a one-sided separator is arranged on the polarizing film on the opposite side of the polarizing film with the pressure-sensitive adhesive layer B on the one-sided side where the pressure-sensitive adhesive layer B is provided. The present invention relates to a method for producing a polarizing film with a double-sided pressure-sensitive adhesive layer, which comprises a step (1) of bonding with a roll.

In the method for producing a polarizing film with a double-sided pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer A with a one-sided separator has the separator SA ₁ on one side of the pressure-sensitive adhesive layer A and the separator SA ₂ on the other side. It was obtained by the step (a) of peeling the separator SA ₂ from the agent layer A.
Peel force _{a 1} of the separator SA _1, peel strength _{a 2} of the separator SA _2, peel force b of the separator SB is _preferably satisfies the a 1> _{a 2} ≧ b, the relationship.

In the production method of the polarizing film with double-sided pressure-sensitive adhesive layer, the peel force _{a 1} of the separator SA _1, peel strength _{a 2} of the separator SA _2, peel force b of the separator SB _is, a 1> 1.5a ₂ ≧ It is preferable to satisfy the relationship of 1.5b.

In the step (1) of bonding with the roll-to-roll in the method for producing a polarizing film with a double-sided pressure-sensitive adhesive layer.
It is preferable to control the ratio (T1 / T2) of the tension T1 of the pressure-sensitive adhesive layer A with a one-sided separator to the tension T2 of the polarizing film with the one-sided pressure-sensitive adhesive layer B to 0.8 or more.

The method for producing the polarizing film with the double-sided pressure-sensitive adhesive layer continues.
The step (b) of peeling the separator SA ₁ from the obtained polarizing film with a double-sided pressure-sensitive adhesive layer, and
The step (2) of attaching the curl adjusting separator SA ₁ ′ to the pressure-sensitive adhesive layer A of the polarizing film with the double-sided pressure-sensitive adhesive layer from which the separator SA ₁ has been peeled off by roll-to-roll can be included.

In the step (2) of bonding with the roll-to-roll in the method for producing a polarizing film with a double-sided pressure-sensitive adhesive layer.
The ratio between the curl adjustment separator SA 1 _'tension T3 and the separator SA ₁ tension T4 of the polarizing film with double-sided pressure-sensitive adhesive layer is peeled off (T3 / T4) is preferably controlled to 0.8 or more.

The method for producing the polarizing film with the double-sided pressure-sensitive adhesive layer continues.
The step (c) of cutting the obtained polarizing film with a double-sided pressure-sensitive adhesive layer to an arbitrary size and the step (d) of cutting the end portion of the cut polarizing film with a double-sided pressure-sensitive adhesive layer can be included.

Further, the present invention is an image display device having at least one polarizing film with a double-sided pressure-sensitive adhesive layer.
The polarizing film with the double-sided pressure-sensitive adhesive layer provided on the most visible side of the polarizing film used in the image display device is the polarizing film with the double-sided pressure-sensitive adhesive layer from which the separator SA ₁ and the separator SB have been removed.
The present invention relates to an image display device, wherein the pressure-sensitive adhesive layer A of the polarizing film with a double-sided pressure-sensitive adhesive layer is arranged on the visual recognition side, and the pressure-sensitive adhesive layer B is arranged on the display portion side.

In the image display device, a member such as a transparent substrate such as a cover glass may be arranged on the visual side of the polarizing film on the visual side. Conventionally, an adhesive layer and then the member are laminated on the polarizing film on the visual side, but the polarizing film with an adhesive layer of the present invention is an adhesive that is bonded to a member such as a transparent substrate on one side of the polarizing film. A polarizing film with a double-sided adhesive layer having a layer and an adhesive layer to be bonded to a display portion on the opposite side thereof. Since the polarizing film also has an adhesive layer on the visual side, a step in manufacturing an image display device. Can be simplified. Further, according to the polarizing film in which the pressure-sensitive adhesive layers are provided on both sides in advance, it is possible to improve the productivity and the quality by processing the polarizing film into a predetermined size.

Further, the polarizing film with double-sided pressure-sensitive adhesive layer of the present invention, a separator SA 1 on both surfaces of the pressure-sensitive adhesive layer A and adhesive layer _B, and includes a separator SB, by the separator SA ₁ and the separator SB etc., the amount of curl Is controlled to be a predetermined amount. By controlling the amount of curl in this way, when the polarizing film with the double-sided adhesive layer is bonded to the display unit, and when a member such as a transparent substrate is bonded, air bubbles are caught at the end of the bonded surface. Can be suppressed, workability can be improved, and yield can be improved.

Further, in the polarizing film with a double-sided pressure-sensitive adhesive layer of the present invention, the storage elastic modulus of the pressure-sensitive adhesive layer A (the pressure-sensitive adhesive layer for bonding members such as a transparent substrate such as a cover glass) arranged on the visible side of the polarizing film is determined. Since the range is controlled, there are no problems such as adhesive stains and the handleability is good. Further, according to the pressure-sensitive adhesive layer in which the storage elastic modulus is controlled within a predetermined range, it is possible to suppress a decrease in step absorption caused by full lamination, and it is possible to suppress durability (suppression of foaming) related to reliability. Can be done.

Further, when the pressure-sensitive adhesive layer A is formed by a multiple pressure-sensitive adhesive layer having at least two pressure-sensitive adhesive layers, even when a member such as a transparent substrate is a member having a step on its surface. It is possible to follow the step and perform bonding without gaps. Even when a member such as a transparent substrate has a step on its surface, the multiple adhesive layer can be bonded without any gaps following the step.

Polarizing film double-sided pressure-sensitive adhesive layer of the present invention, for example, a pressure-sensitive adhesive layer A with one side separator having a pressure-sensitive adhesive layer A, a one-sided pressure-sensitive adhesive layer B Tsukehen light film comprises a separator S B, a roll-to-roll It can be manufactured by the step of laminating, and by the step of laminating with the roll-to-roll, the handleability can be improved and glue stains can be suppressed, and further, the processability of the obtained polarizing film with a double-sided adhesive layer can be improved. Can be improved.

Further, in the step of laminating by roll-to-roll, the polarizing film with a double-sided pressure-sensitive adhesive layer obtained by controlling the tensions of the pressure-sensitive adhesive layer A with a one-sided separator and the polarizing film with the one-sided pressure-sensitive adhesive layer B can be obtained. The curl amount can be controlled to be a predetermined amount. Further, the curl amount of the polarizing film with the double-sided pressure-sensitive adhesive layer can be controlled to be a predetermined amount by replacing the separator SA ₁ in the polarizing film with the double-sided pressure-sensitive adhesive layer.

It is sectional drawing which shows typically one Embodiment of the polarizing film with a double-sided pressure-sensitive adhesive layer of this invention. It is sectional drawing which shows typically one Embodiment of the polarizing film with a double-sided pressure-sensitive adhesive layer of this invention. It is sectional drawing which shows typically the curl amount of the polarizing film with a double-sided pressure-sensitive adhesive layer of this invention. It is sectional drawing which shows typically the curl amount of the polarizing film with a double-sided pressure-sensitive adhesive layer of this invention. It is a conceptual diagram which shows typically the state which the image display apparatus and the member such as a transparent substrate are bonded with the polarizing film with the double-sided pressure-sensitive adhesive layer of this invention. It is sectional drawing which shows one Embodiment of the image display apparatus typically. It is sectional drawing which shows one Embodiment of the image display apparatus typically. It is sectional drawing which shows one Embodiment of the image display apparatus typically. It is sectional drawing which shows typically one Embodiment of the pressure-sensitive adhesive layer A with a separator on both sides. It is sectional drawing which shows typically one Embodiment of the step (1) of sticking by roll-to-roll in the manufacturing method of the polarizing film with a double-sided pressure-sensitive adhesive layer of this invention. It is sectional drawing which shows typically one Embodiment of the step (2) of sticking roll-to-roll using the separator for curl adjustment in the manufacturing method of the polarizing film with a double-sided pressure-sensitive adhesive layer of this invention.

Hereinafter, embodiments of the polarizing film with a double-sided pressure-sensitive adhesive layer of the present invention and the like will be described in detail with reference to the drawings. However, the present invention is not limited to the embodiments of the drawings.

As shown in FIGS. 1a and 1b, the polarizing film 10 (10') with a double-sided pressure-sensitive adhesive layer of the present invention has a pressure-sensitive adhesive layer A and a pressure-sensitive adhesive layer B on both sides of the polarizing film 1 and the polarizing film 1. Have. Further, the polarizing film 10 (10') with a double-sided pressure-sensitive adhesive layer of the present invention includes a separator SA _{1 on} the pressure-sensitive adhesive layer A and a separator SB on the pressure-sensitive adhesive layer B. As the separator SA ₁ , a curl adjusting separator SA ₁ ′ described later can be used.

In FIG. 1a, the case where the pressure-sensitive adhesive layer A is one layer is illustrated, but the pressure-sensitive adhesive layer A is the first pressure-sensitive adhesive layer (a) and the second pressure-sensitive adhesive layer from the outermost surface side (visual side). A multi-adhesive layer having (b) in these orders can be obtained. FIG. 1b illustrates the case where the pressure-sensitive adhesive layer A is a multi-layered structure consisting of a first pressure-sensitive adhesive layer (a) and a second pressure-sensitive adhesive layer (b). The number of layers of the multiple pressure-sensitive adhesive layer according to the pressure-sensitive adhesive layer A is not limited, but usually up to about 5 layers can be provided. The number of layers of the multi-adhesive layer is preferably 2 to 4, and more preferably 2 to 3 layers. Each layer of the multiple adhesive layer is provided in direct contact with each other.

In the multiple pressure-sensitive adhesive layers, pressure-sensitive adhesive layers having different compositions are used for adjacent pressure-sensitive adhesive layers, but pressure-sensitive adhesive layers having the same composition can be used for non-adjacent pressure-sensitive adhesive layers. In FIG. 1b, the first pressure-sensitive adhesive layer (a) and the second pressure-sensitive adhesive layer (b) have different compositions. When the first pressure-sensitive adhesive layer (a), the second pressure-sensitive adhesive layer (b) and the third pressure-sensitive adhesive layer (c) are used as the pressure-sensitive adhesive layer A from the outermost surface side (visual side), the first pressure-sensitive adhesive layer (c) is used. The agent layer (a) and the second pressure-sensitive adhesive layer (b) have different compositions, and the second pressure-sensitive adhesive layer (b) and the third pressure-sensitive adhesive layer (c) have different compositions. The first pressure-sensitive adhesive layer (a), the second pressure-sensitive adhesive layer (b), and the third pressure-sensitive adhesive layer (c) may have different compositions, but the first pressure-sensitive adhesive layer (a) and the third pressure-sensitive adhesive layer (a) and the third pressure-sensitive adhesive layer (c) may have different compositions. It may have the same composition as the agent layer (c).

2a and 2b are cross-sectional views schematically showing the curl amount of the polarizing film 10 (10') with a double-sided pressure-sensitive adhesive layer of the present invention. The curl amount is measured on a rectangular object obtained by cutting a polarizing film 10 (10') with a double-sided pressure-sensitive adhesive layer by 300 mm in the absorption axis direction and 250 mm in the direction orthogonal to the absorption axis of the polarizing film 1. As shown in FIGS. 2a and 2b, the amount of curl is measured by placing it on a horizontal plane so that the surface on which the curl is convex is on the lower side. Further, as shown in FIG. 2a, the curl amount was measured by placing the separator SB side of the polarizing film 10 (10') with a double-sided adhesive layer on a horizontal plane so as to be on the lower side. Is displayed as "+", and as shown in FIG. 2b, the curl amount (h) measured by placing the separator SA ₁ (SA ₁ ') on a horizontal surface so as to be on the lower side is displayed as "-". Will be done. The curl amount (h) is the distance (mm) of the longest point from the horizontal plane among the four points at the corners of the rectangular object.

The curl amount (h) is controlled to −10 mm to +60 mm from the viewpoint of workability and yield. The curl amount (h) is preferably "+" as shown in FIG. 2a from the viewpoint of workability and yield, and more preferably +2 mm to +30 mm, further preferably +5 mm to +20 mm.

<Adhesive layer>
The pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B of the present invention will be described below. Both the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B are "transparent" and can be satisfied because the haze value measured at a thickness of 25 μm is 2% or less. The haze value is preferably 0 to 1.5%, more preferably 0 to 1%.

<Thickness of adhesive layer>
Further, the total thickness of the pressure-sensitive adhesive layer A is preferably 5 μm to 1 mm. The overall thickness of the pressure-sensitive adhesive layer A can be appropriately designed depending on where the pressure-sensitive adhesive layer A is applied. The overall thickness of the pressure-sensitive adhesive layer A is preferably 10 μm to 500 μm, more preferably 20 μm to 300 μm.

When the pressure-sensitive adhesive layer A is a multiple pressure-sensitive adhesive layer having a first pressure-sensitive adhesive layer (a) and a second pressure-sensitive adhesive layer (b), the thickness of each pressure-sensitive adhesive layer is 3 to 200 μm. It is preferable, more preferably 5 to 150 μm, and further preferably 10 to 100 μm.

As shown in FIG. 1b, when the pressure-sensitive adhesive layer A has a two-layer structure of the first pressure-sensitive adhesive layer (a) and the second pressure-sensitive adhesive layer (b), the thickness of the first pressure-sensitive adhesive layer (a) is It is preferably 3 to 200 μm, more preferably 5 to 100 μm, and further preferably 10 to 75 μm. The thickness of the second pressure-sensitive adhesive layer (b) is preferably 10 to 300 μm, more preferably 20 to 150 μm, and further preferably 50 to 100 μm. The difference between the thickness of the first pressure-sensitive adhesive layer (a) and the thickness of the second pressure-sensitive adhesive layer (b) is preferably 20 to 270 μm, more preferably 30 to 200 μm, from the viewpoint of step absorption and processability. It is preferable to have it.

On the other hand, the thickness of the pressure-sensitive adhesive layer B is generally 1 to 500 μm, preferably 5 to 200 μm, and particularly preferably 10 to 100 μm.

<Storage modulus of adhesive layer>
The storage elastic modulus of the pressure-sensitive adhesive layer A at 23 ° C. is controlled to 0.02 to 0.3 MPa. The pressure-sensitive adhesive layer A whose storage elastic modulus is controlled within such a range can suppress adhesive stains, and can improve the workability of bonding to a transparent substrate and improve the yield. The storage elastic modulus is preferably 0.02 to 0.4 MPa, more preferably 0.03 to 0.3 MPa, and further preferably 0.05 to 0.1 MPa. Controlling the storage elastic modulus of the pressure-sensitive adhesive layer A is also preferable in order to satisfy the step absorption property.

<Peeling power of adhesive layer>
The pressure-sensitive adhesive layer A is provided with a separator SA ₁ (SA ₁ ′), and the pressure-sensitive adhesive layer B is provided with a separator SB. The peeling force a ₁ of the separator SA ₁ (SA ₁ ′) with respect to the pressure-sensitive adhesive layer A is preferably 0.01 to 5 N / 50 mm, more preferably 0.05 to 2 N / 50 mm, and further. Is preferably 0.1 to 1 N / 50 mm. The peeling force b of the separator SB with respect to the pressure-sensitive adhesive layer B is preferably 0.01 to 5 N / 50 mm, more preferably 0.05 to 2 N / 50 mm, and further 0.1 to 0.1. It is preferably 1N / 50 mm.

Further, the release force a ₁ of the separator SA 1 _(SA 1 _') is adjusted to be higher than the peel strength b of the separator SB it is preferable from the viewpoint of bonding above the display panel. The difference in peel strength b of the peel force _{a 1} and the separator SB separator _{SA 1 (SA} 1 ') is preferably a 0.01~2N / 50mm from the viewpoint of preventing peeling failure, further, 0.02 It is preferably ~ 1N / 50mm.

The measurement of the storage elastic modulus and the peeling force is based on the description of the examples.

As shown in FIG. 3, in the polarizing film with a double-sided pressure-sensitive adhesive layer of the present invention, the separator SA ₁ (SA ₁ ′) and the separator SB removed are applied to an image display device. The polarizing film according to the polarizing film with a double-sided pressure-sensitive adhesive layer of the present invention is applied as a polarizing film provided on the most visible side in the polarizing film used in an image display device. The pressure-sensitive adhesive layer A of the polarizing film with a double-sided pressure-sensitive adhesive layer of the present invention is arranged on the visual side of an image display device and is bonded to a member C such as a transparent substrate. The pressure-sensitive adhesive layer B is arranged on the opposite side of the pressure-sensitive adhesive layer A in the polarizing film 1 and is bonded to the display unit D.

Examples of the member C include an input device such as a touch panel applied on the visual side of the image display device, a cover glass, a transparent substrate such as a plastic cover, and the like.

The display unit D forms a part of the image display device together with at least one polarizing film 1, and includes a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), electronic paper, and the like. Can be given. As the display unit D, a liquid crystal display device having a liquid crystal layer 5 used together with the polarizing film 1 can be preferably used. 4a to 4c show sectional views schematically showing a typical embodiment of an image display device (liquid crystal display device) to which the polarizing film with an adhesive layer of the present invention is applied. In the image display device (liquid crystal display device) of FIGS. 4a to 4c, the upper polarizing film 1 is located on the most visible side.

The image display device (liquid crystal display device) shown in FIG. 4a includes a cover glass C / adhesive layer A / polarizing film 1 (visual side) / adhesive layer 2 (B) / antistatic layer 3 / glass substrate 4 / liquid crystal layer. It has a structure of 5 / driving electrode 6 / glass substrate 4 / adhesive layer 2 / polarizing film 1. The antistatic layer 3 and the driving electrode 6 can be formed from a transparent conductive layer. The antistatic layer 3 can be formed arbitrarily.

The image display device (liquid crystal display device) shown in FIG. 4b is a case where the transparent conductive layer is used as an electrode of a touch panel (in-cell type touch panel), and the cover glass C / adhesive layer A / polarizing film 1 (visual side). It has a structure of / adhesive layer 2 (B) / antistatic layer / sensor layer 7 / glass substrate 4 / liquid crystal layer 5 / drive electrode / sensor layer 8 / glass substrate 4 / adhesive layer 2 / polarizing film 1. The antistatic layer / sensor layer 7 and the drive electrode / sensor layer 8 can be formed of a transparent conductive layer.

The image display device (liquid crystal display device) shown in FIG. 4c is a case where the transparent conductive layer is used as an electrode of a touch panel (on-cell type touch panel), and the cover glass C / adhesive layer A / polarizing film 1 / adhesive layer. It has a configuration of 2 (B) / antistatic layer / sensor layer 7 / sensor layer 9 / glass substrate 4 / liquid crystal layer 5 / drive electrode 6 / glass substrate 4 / adhesive layer 2 / polarizing film 1. The antistatic layer / sensor layer 7, the sensor layer 9, and the drive electrode 6 can be formed from the transparent conductive layer.

As the polarizing film, a polarizing film having a transparent protective film on one side or both sides of the polarizer is generally used. A functional layer such as a hard coat layer may be provided on the transparent protective film of the polarizing film. In addition, as the image display device, an optical film used for forming an image display device such as a liquid crystal display device or an organic EL display device is appropriately used. Examples of the optical film include a reflective plate, an antitransmissive plate, a retardation plate (including a wave plate such as 1/2 or 1/4), an optical compensation film, a visual compensation film, a liquid crystal display device such as a brightness improving film, and the like. An optical layer that may be used to form the film. These can be used alone as an optical film, or can be laminated on the polarizing film for practical use and used as one layer or two or more layers.

In addition, in FIGS. 4a to 4c, the pressure-sensitive adhesive layer 2 is disclosed for adhering to other members such as a liquid crystal cell (glass substrate). The pressure-sensitive adhesive layer 2 on the visual side (upper side) of the liquid crystal cell is applied as the pressure-sensitive adhesive layer B. For the pressure-sensitive adhesive layer 2, for example, various pressure-sensitive adhesives based on polymers such as acrylic polymers, silicone-based polymers, polyesters, polyurethanes, polyamides, polyethers, fluorine-based polymers and rubber-based polymers can be appropriately selected and used. it can. In particular, an acrylic pressure-sensitive adhesive that has excellent optical transparency, exhibits appropriate wettability, cohesiveness, and adhesiveness, and has excellent weather resistance and heat resistance is preferable.

A liquid crystal display device generally incorporates a drive circuit by appropriately assembling components such as a liquid crystal cell (glass substrate / liquid crystal layer / glass substrate configuration), polarizing films arranged on both sides thereof, and a lighting system as needed. It is formed by things such as. As the liquid crystal cell, any type such as TN type, STN type, π type, VA type, and IPS type can be used. Further, an appropriate liquid crystal display device such as a lighting system using a backlight or a reflector can be formed. Further, when forming the liquid crystal display device, for example, an appropriate component such as a diffuser plate, an anti-glare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffuser plate, and a backlight is placed in one layer or at an appropriate position. Two or more layers can be arranged.

A touch panel can be used as the member C. The touch panel C is a capacitive touch panel, and a transparent substrate, an adhesive layer 2, and a transparent conductive film are laminated in this order. Further, the transparent conductive film can be laminated in two or more layers. The transparent substrate can have a sensor layer. The transparent substrate can be applied to an image table device (liquid crystal display device) by itself as a cover glass, a plastic cover, or the like. In addition, a hard coat film may be provided on the transparent conductive film on the side opposite to the transparent substrate of the touch panel C.

Examples of the transparent substrate include a glass plate and a transparent acrylic plate (PMMA plate). The transparent substrate is a so-called cover glass and can be used as a decorative panel. As the transparent conductive film, a glass plate or a transparent plastic film (particularly a PET film) provided with a transparent conductive film is preferable. Examples of the transparent conductive film include thin films made of metals, metal oxides and mixtures thereof, and examples thereof include thin films of ITO (indium tin oxide), ZnO, SnO and CTO (cadmium oxide). The thickness of the transparent conductive film is not particularly limited, but is about 10 to 200 nm. As the transparent conductive film, an ITO film in which an ITO film is provided on a PET film is a typical example. The transparent conductive film can be provided via the undercoat layer. A plurality of undercoat layers can be provided. An oligomer migration prevention layer can be provided between the transparent plastic film base material and the pressure-sensitive adhesive layer. The hard coat film is preferably a transparent plastic film such as a PET film that has been hard coated.

The polarizing film 10 with a double-sided pressure-sensitive adhesive layer of the present invention is, for example, a polarizing film 12 with a one-sided pressure-sensitive adhesive layer B having a polarizing film 1 and a pressure-sensitive adhesive layer B and having a separator SB on the pressure-sensitive adhesive layer B. And the pressure-sensitive adhesive layer A (11) with a one-sided separator having the pressure-sensitive adhesive layer A on the separator SA ₁ is placed on the opposite side of the polarizing film 12 with the one-sided pressure-sensitive adhesive layer B where the pressure-sensitive adhesive layer B is provided. It can be manufactured by sticking the pressure-sensitive adhesive layer A of the pressure-sensitive adhesive layer A (11) with a separator on one side to the polarizing film 1 so as to be arranged. As shown in FIG. 6, the manufacturing method is preferably carried out by the step (1) of laminating by roll-to-roll. In FIG. 6, a step (1) in which the polarizing film 12 with the one-side adhesive layer B and the adhesive layer A (11) with the one-side separator are bonded between the pair of bonding rolls R1 and R2, which are conveyed from the delivery roll. ) Is performed, and a polarizing film 10 with a double-sided pressure-sensitive adhesive layer is obtained by a take-up roll.

Further, the pressure-sensitive adhesive layer A (11) with a single-sided separator can be obtained from the pressure-sensitive adhesive layer A (14) with a double-sided separator having a separator SA ₁ on one side of the pressure-sensitive adhesive layer A and a separator SA ₂ on the other side. it can. As shown in FIG. 5, the pressure-sensitive adhesive layer A (14) with the separators on both sides can be represented by the configuration of the separator SA ₁ / the pressure-sensitive adhesive layer A / the separator SA ₂ . In FIG. 6, the pressure-sensitive adhesive layer A (14) with a separator on both sides, which is conveyed from the delivery roll, is subjected to a step (a) of peeling the separator SA ₂ by the peeling roll R3, and is bonded to the step (1). The pressure-sensitive adhesive layer A (11) with a separator on one side is supplied.

When using the both side separator pressure-sensitive adhesive layer A (14), the peel force _{a 1} of the separator SA _1, peel strength _{a 2} of the separator SA _2, peel force b of the separator SB _is a 1> _{a 2} Satisfying the relationship of ≧ b is preferable from the viewpoint of the order of product processes and the order of bonding processes to liquid crystal panels, organic EL panels, and the like. Furthermore, the release force _{a 1} of the separator SA _1, peel strength _{a 2} of the separator SA _2, peel force b of the separator SB _is a 1> 1.5a ₂ ≧ 1.5b, to satisfy the relation However, it is preferable from the viewpoint of improving workability.

Peel force _{a 1} of the separator SA _1, peel strength b of the separator SB is as described above. The peeling force a ₂ of the separator SA ₂ is preferably 0.01 to 5 N / 50 mm, more preferably 0.05 to ₂ N / 50 mm, and further preferably 0.05 to 1 N / 50 mm. Is preferable. It is preferably the difference in release force _{a 2} release force _{a 1} and the separator SA ₂ of the separator SA ₁ is 0.01~1N / 50mm in view of workability in bonding step to the polarizing plate, and further , 0.03 to 0.5 N / 50 mm is preferable.

Further, the polarizing film 10 with a double-sided pressure-sensitive adhesive layer of the present invention has a tension T1 of the pressure-sensitive adhesive layer A (11) with a separator and polarized light with a pressure-sensitive adhesive layer B on one side in the step (1) of bonding by roll-to-roll. It is preferable to control the ratio of tension T2 (T1 / T2) of the film 12 to 0.8 or more. In FIG. 6, the tension T1 and the tension T2 can be controlled by the rolls R11 and R12.

The curl amount can be adjusted by controlling the tension ratio (T1 / T2) within the above range. The tension ratio (T1 / T2) is preferably 0.9 or more, more preferably 1 or more, and further preferably 3 or more. On the other hand, if the tension ratio (T1 / T2) becomes too large, the curl amount becomes too large and the bonding accuracy decreases in the bonding process to the panel. Therefore, the tension ratio (T1 / T2) is 10 or less. It is preferable, more preferably 6 or less, and further preferably 4 or less.

The tension T1 is preferably 8 to 500 N / m, more preferably 50 to 300 N / m, and further preferably 100 to 200 N / m.
The tension T2 is preferably 10 to 400 N / m, more preferably 20 to 200 N / m, and further preferably 40 to 100 N / m.

Further, in the present invention, after the polarizing film 10 with the double-sided pressure-sensitive adhesive layer is manufactured, the separator SA ₁ is subsequently peeled from the pressure-sensitive adhesive layer A of the obtained polarizing film 10 with the double-sided pressure-sensitive adhesive layer, and then the separator SA _The polarizing film 10'with a double-sided pressure-sensitive adhesive layer can be produced by adhering the curl adjusting separator SA 1'to the pressure-sensitive adhesive layer A of the polarizing film 13 with a double-sided pressure-sensitive adhesive layer _{1 from} which ₁ . By using the curl adjusting separator SA ₁ ′ instead of the separator SA ₁ , the curl amount of the polarizing film 10 ′ with the double-sided adhesive layer can be adjusted. As shown in FIG. 7, the manufacturing method is preferably carried out by the step (2) of laminating by roll-to-roll.

In FIG. 7, the polarizing film 10 with a double-sided pressure-sensitive adhesive layer conveyed from the delivery roll is subjected to a step (b) of peeling the separator SA ₁ by the peeling roll R6. Then, a double-sided pressure-sensitive adhesive layer-attached polarizing film 13 to be conveyed, but the curl adjustment separator SA 1 _', be bonded Step (2) between the rolls R4, R5 bonded pair is performed, a take-up roll Therefore, a polarizing film 10'with a double-sided pressure-sensitive adhesive layer is obtained.

The peeling force a ₁ ′ of the curl adjusting separator SA ₁ ′ is preferably in the same range as the peeling force a ₁ of the separator SA ₁ , and in relation to the peeling force b of the separator SB, a It is preferable to satisfy the relationship of ₁ ′> 1.5b from the viewpoint of adjusting the curl amount.

Also, double-sided double-sided pressure-sensitive adhesive layer-attached polarizing film 10 'of the present invention, in the step (2) of bonding by the roll-to-roll, the separator SA ₁ and tension T3 of the curl adjustment separator SA _1' is peeled off It is preferable to control the ratio (T3 / T4) of the polarizing film 13 with the pressure-sensitive adhesive layer to the tension T4 to 0.8 or more. In FIG. 7, the tension T3 and the tension T4 can be controlled by the rolls R13 and R14.

The curl amount can be adjusted by controlling the tension ratio (T3 / T4) within the above range. The tension ratio (T3 / T4) is preferably 0.9 or more, more preferably 1 or more, and further preferably 3 or more. On the other hand, if the tension ratio (T3 / T4) becomes too large, the curl amount becomes too large and the bonding accuracy decreases in the bonding process to the panel. Therefore, the tension ratio (T3 / T4) is 10 or less. Is preferable, and more preferably 6 or less, and further preferably 4 or less.

The tension T3 is preferably 8 to 500 N / m, more preferably 50 to 300 N / m, and further preferably 100 to 200 N / m.
The tension T4 is preferably 10 to 400 N / m, more preferably 20 to 200 N / m, and further preferably 40 to 100 N / m.

The magnitude of the tension can be adjusted by the torque of the roll or the like, and the method of applying the tension is not particularly limited. However, when the film or the like is fed by the roll, the tension can be applied in the feeding direction. Further, the tension can be measured by, for example, a load cell type tension pickup roll that can be measured by a load applied to the transport roll. The tension is measured by the method described in Examples.

The method for producing the obtained polarizing film with a double-sided pressure-sensitive adhesive layer is a step (c) of cutting to an arbitrary size and a step of cutting the end portion of the cut polarizing film with a double-sided pressure-sensitive adhesive layer (c). d) can be included. The cutting step (d) can include a polishing step.

<Material of adhesive layer>
Further, as the material for forming the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B of the present invention, those containing various base polymers can be used. The type of base polymer is not particularly limited, but for example, rubber-based polymer, (meth) acrylic-based polymer, silicone-based polymer, urethane-based polymer, vinyl alkyl ether-based polymer, polyvinyl alcohol-based polymer, polyvinylpyrrolidone-based polymer, poly. Examples thereof include various polymers such as acrylamide-based polymers and cellulose-based polymers.

Among these base polymers, those having excellent optical transparency, exhibiting appropriate wettability, cohesiveness, and adhesive properties, and having excellent weather resistance and heat resistance are preferably used. A (meth) acrylic polymer is preferably used to exhibit such characteristics. Hereinafter, an acrylic pressure-sensitive adhesive based on a (meth) acrylic polymer containing an alkyl (meth) acrylate as a monomer unit as a material for forming the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B will be described.

The (meth) acrylic polymer can be obtained by polymerizing a monomer component containing an alkyl (meth) acrylate having an alkyl group having 4 to 24 carbon atoms at the end of the ester group. The alkyl (meth) acrylate refers to an alkyl acrylate and / or an alkyl methacrylate, which has the same meaning as the (meth) of the present invention.

Examples of the alkyl (meth) acrylate include those having a linear or branched chain alkyl group having 4 to 24 carbon atoms. The alkyl (meth) acrylate may be used alone or in combination of two or more.

As the alkyl (meth) acrylate, for example, the alkyl (meth) acrylate having a branch having 4 to 9 carbon atoms can be exemplified. The alkyl (meth) acrylate is preferable because it can easily balance the adhesive properties. Examples of the alkyl (meth) acrylate include n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, n-pentyl (meth) acrylate, and isopentyl (meth) acrylate. Examples thereof include meta) acrylate, isohexyl (meth) acrylate, isoheptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, and isononyl (meth) acrylate. Further, it is preferable that the (meth) acrylic polymer according to the pressure-sensitive adhesive layer A contains the largest amount of 2-ethylhexyl acrylate as a monomer unit from the viewpoint of controlling the storage elastic modulus and absorbing steps. When the pressure-sensitive adhesive layer A is a multiple pressure-sensitive adhesive layer having at least the first pressure-sensitive adhesive layer (a) and the second pressure-sensitive adhesive layer (b), the pressure-sensitive adhesive layer A is used as the multiple pressure-sensitive adhesive layer (as a total of each layer). The (meth) acrylic polymer preferably contains the most 2-ethylhexyl acrylate as a monomer unit. On the other hand, the (meth) acrylic polymer according to the pressure-sensitive adhesive layer B contains the largest amount of butyl acrylate as a monomer unit, which controls the storage elastic modulus, and from the viewpoint of processability, storage property, and durability. preferable.

In the present invention, the alkyl (meth) acrylate having an alkyl group having 4 to 24 carbon atoms at the ester terminal is 40% by weight or more based on the total amount of the monofunctional monomer component forming the (meth) acrylic polymer. It is preferably 50% by weight or more, more preferably 60% by weight or more. It is preferable to use 40% by weight or more because it is easy to balance the adhesive properties.

The monomer component forming the (meth) acrylic polymer of the present invention may contain a copolymerization monomer other than the alkyl (meth) acrylate as a monofunctional monomer component. The copolymerizable monomer can be used as the remainder of the alkyl (meth) acrylate in the monomer component.

As the copolymerization monomer, for example, a cyclic nitrogen-containing monomer can be included. 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 from the viewpoint of dielectric constant and cohesiveness.

In the present invention, the cyclic nitrogen-containing monomer is preferably 45% by weight or less, more preferably 0.5 to 40% by weight, still more preferably 0.5% by weight, based on the total monomer components forming the (meth) acrylic polymer. It is 0.5 to 30% by weight. The use of the cyclic nitrogen-containing monomer in the above range is preferable in terms of controlling the surface resistance value, particularly compatibility with the ionic compound when an ionic compound is used, and durability of the antistatic function.

The monomer component forming the (meth) acrylic polymer of the present invention can include, for example, a hydroxyl group-containing monomer, a carboxyl group-containing monomer, and a monomer having a cyclic ether group as a monofunctional monomer component.

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; Examples thereof include hydroxyalkylcycloalkane (meth) acrylates such as 4-hydroxymethylcyclohexyl) methyl (meth) acrylates. In addition, hydroxyethyl (meth) acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether and the like can be mentioned. These can be used alone or in combination. Of these, hydroxyalkyl (meth) acrylates are preferable.

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. A pressure-sensitive adhesive containing a (meth) acrylic polymer obtained from a monomer component that does not contain a carboxyl group-containing monomer can form a pressure-sensitive adhesive layer in which metal corrosion and the like caused by a carboxyl group are reduced.

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.

In the present invention, the hydroxyl group-containing monomer, the carboxyl group-containing monomer, and the monomer having a cyclic ether group are 30% by weight or less based on the total amount of the monofunctional monomer component forming the (meth) acrylic polymer. Is preferable, and more preferably 27% by weight or less, and further preferably 25% by weight or less.

The monomer component forming the (meth) acrylic polymer of the present invention contains, for example, CH ₂ = C (R ¹ ) COOR ² (where R ¹ is a hydrogen or methyl group and R ² is a carbon number 1) as a copolymerization monomer. It can contain an alkyl (meth) acrylate represented by (representing an unsubstituted alkyl group, a substituted alkyl group, or a cyclic cycloalkyl group) of (3).

Here, the unsubstituted alkyl group having 1 to 3 carbon atoms or the substituted alkyl group as R ² represents a linear or branched alkyl group. In the case of a substituted alkyl group, the substituent 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 methyl (meth) acrylate, ethyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, and cyclohexyl (meth). Examples thereof include meta) acrylate, 3,3,5-trimethylcyclohexyl (meth) acrylate and isobornyl (meth) acrylate. These can be used alone or in combination.

In the present invention, the (meth) acrylate represented by CH ₂ = C (R ¹ ) COOR ² is 45% by weight or less based on the total amount of the monofunctional monomer component forming the (meth) acrylic polymer. It can be used, preferably 35% by weight or less. Further, 30% by weight or less is preferable.

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 monomers such as methoxypolypropylene glycol acrylate; Acrylic acid-based monomers such as tetrahydrofurfuryl (meth) acrylate, fluorine (meth) acrylate, silicone (meth) acrylate and 2-methoxyethyl acrylate; containing amide groups Monomers, amino group-containing monomers, imide group-containing monomers, N-acryloylmorpholin, vinyl ether monomers and the like can also be used. Further, as the copolymerization monomer, a monomer having a cyclic structure such as terpene (meth) acrylate and dicyclopentanyl (meth) acrylate can 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.

The copolymerization monomer can be appropriately selected when preparing the (meth) acrylic polymer as the base polymer when forming the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B. As the copolymerization monomer, when the first pressure-sensitive adhesive layer (a) in the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B are formed by an acrylic pressure-sensitive adhesive, cohesive force, adhesive strength improvement, transparency, and durability From the viewpoint of properties, it is preferable that at least one of these contains at least one of (meth) acrylic acid and a nitrogen-containing monomer as a monomer unit.

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, propoxylated pentaerythritol triacrylate, dipentaerythritol hexa (meth) Acrylate, 1,2-ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, trimethylpropantri (meth) acrylate, tetramethylol methane Ester compound of polyhydric alcohol such as tri (meth) acrylate and (meth) acrylic acid; allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butanediol di (meth) ) Acrylate, hexanediol di (meth) acrylate and the like can be mentioned. Of 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. When the amount of the polyfunctional monomer used is within the above range, the adhesive strength can be improved.

For the production of such (meth) acrylic polymers, known production methods such as solution polymerization, radiation polymerization such as ultraviolet 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.

The polymerization initiator, chain transfer agent, emulsifier and the like used for 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 of the (meth) acrylic polymer used is appropriately adjusted according to these types.

For example, in solution polymerization and the like, 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) Azobisisobuty, 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropion amidine] hydrate (manufactured by Wako Junyaku Co., Ltd., VA-057) and other azo-based initiators, potassium persulfate, excess Persulfate such as ammonium sulfate, di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxyneodecano Ate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexa Noate, di (4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di (t-hexylperoxy) cyclohexane, t-butylhydroperoxide, hydrogen peroxide Peroxide-based initiators such as, a combination of persulfate and sodium hydrogen sulfite, and a redox-based initiator that combines a peroxide and a reducing agent such as a combination of peroxide and sodium ascorbate. However, it is not limited to these.

The polymerization initiator may be used alone or in combination of two or more, but the total content is 0.005 to 1 part by weight with respect to 100 parts by weight of the monomer. It is preferably about 0.02 to 0.5 parts by weight, and more preferably about 0.02 to 0.5 parts by weight.

In order to produce the (meth) acrylic polymer having the weight average molecular weight using, for example, 2,2'-azobisisobutyronitrile as the polymerization initiator, the amount of the polymerization initiator used is a monomer. It is preferably about 0.06 to 0.2 parts by weight, more preferably about 0.08 to 0.175 parts by weight, based on 100 parts by weight of the total amount of the components.

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 0.1 part 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 Corporation), and the like. Since the reactive emulsifier is incorporated into the polymer chain after polymerization, it has good water resistance and is preferable. The amount of the emulsifier used is more preferably 0.3 to 5 parts by weight and 0.5 to 1 part by weight from the viewpoint of polymerization stability and mechanical stability with respect to 100 parts by weight of the total amount of the monomer components.

Further, when the (meth) acrylic polymer is produced by active energy ray polymerization, it can be produced by polymerizing the monomer component by irradiating the active energy ray such as an electron beam or ultraviolet rays. When the active energy ray polymerization is carried out by an electron beam, it is not particularly necessary to include a photopolymerization initiator in the monomer component, but particularly when the active energy ray polymerization is carried out by ultraviolet polymerization. A photopolymerization initiator can be contained in the monomer component because of the advantage that the polymerization time can be shortened. The photopolymerization initiator may be used alone or in combination of two or more. As the monomer component, a syrup obtained by partially polymerizing in advance can be used for irradiation.

The photopolymerization initiator is not particularly limited, but is not particularly limited as long as it initiates photopolymerization, and a commonly used photopolymerization initiator can be used. For example, benzoin ether-based photopolymerization initiator, acetophenone-based photopolymerization initiator, α-ketol-based photopolymerization initiator, aromatic sulfonyl chloride-based photopolymerization initiator, photoactive oxime-based photopolymerization initiator, benzoin-based photopolymerization initiator. Agents, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, 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-on [trade name: Irgacure 651, manufactured by BASF], anisoin methyl ether and the like can be mentioned. Examples of the acetophenone-based photopolymerization initiator include 1-hydroxycyclohexylphenyl ketone [trade name: Irgacure 184, manufactured by BASF], 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 1- [4-( 2-Hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane-1-one [trade name: Irgacure 2959, manufactured by BASF], 2-hydroxy-2-methyl-1-phenyl-propane- 1-on [trade name: DaroCure 1173, manufactured by BASF], methoxyacetophenone and the like can be mentioned. Examples of the α-ketol-based photopolymerization initiator include 2-methyl-2-hydroxypropiophenone and 1- [4- (2-hydroxyethyl) -phenyl] -2-hydroxy-2-methylpropane-1-. On, etc. can be mentioned. Examples of the aromatic sulfonyl chloride-based photopolymerization initiator include 2-naphthalene sulfonyl chloride and the like. Examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,2-propanedione-2- (O-ethoxycarbonyl) -oxime and the like.

Further, the benzoin-based photopolymerization initiator includes, for example, benzoin and the like. The benzyl-based photopolymerization initiator includes, for example, benzyl and the like. Benzophenone-based photopolymerization initiators include, for example, benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexylphenyl ketone and the like. The ketal-based photopolymerization initiator includes, for example, 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, and isopropylthioxanthone. 2,4-Diisopropylthioxanthone, dodecylthioxanthone and the like are included.

Examples of the acylphosphine oxide-based photopolymerization initiator include bis (2,6-dimethoxybenzoyl) phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) (2,4,4-trimethylpentyl) phosphine oxide, and bis. (2,6-dimethoxybenzoyl) -n-butylphosphine oxide, bis (2,6-dimethoxybenzoyl)-(2-methylpropan-1-yl) phosphine oxide, bis (2,6-dimethoxybenzoyl)-(1 -Methylpropan-1-yl) phosphine oxide, bis (2,6-dimethoxybenzoyl) -t-butylphosphine oxide, bis (2,6-dimethoxybenzoyl) cyclohexylphosphine oxide, bis (2,6-dimethoxybenzoyl) octyl Phosphine oxide, bis (2-methoxybenzoyl) (2-methylpropan-1-yl) phosphine oxide, bis (2-methoxybenzoyl) (1-methylpropan-1-yl) phosphine oxide, bis (2,6-di) Ethoxybenzoyl) (2-methylpropan-1-yl) phosphine oxide, bis (2,6-diethoxybenzoyl) (1-methylpropan-1-yl) phosphine oxide, bis (2,6-dibutoxybenzoyl) ( 2-Methylpropan-1-yl) phosphine oxide, bis (2,4-dimethoxybenzoyl) (2-methylpropan-1-yl) phosphine oxide, bis (2,4,6-trimethylbenzoyl) (2,4- Dipentoxyphenyl) phosphine oxide, bis (2,6-dimethoxybenzoyl) benzyl phosphine oxide, bis (2,6-dimethoxybenzoyl) -2-phenylpropylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2- Phenylethylphosphine oxide, bis (2,6-dimethoxybenzoyl) benzylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2-phenylpropylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2-phenylethylphosphine Oxide, 2,6-dimethoxybenzoylbenzylbutylphosphine oxide, 2,6-dimethoxybenzoylbenzyloctylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,5-diisopropylphenylphosphine oxide, bis (2,4) , 6-trimethylbenzoyl) -2-methylphenylphosphine oki Sid, bis (2,4,6-trimethylbenzoyl) -4-methylphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,5-diethylphenylphosphine oxide, bis (2,4,6- Trimethylbenzoyl) -2,3,5,6-tetramethylphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,4-di-n-butoxyphenylphosphine oxide, 2,4,6-trimethyl Benzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) isobutylphosphine oxide, 2,6-dimethitoxybenzoyl-2 , 4,6-trimethylbenzoyl-n-butylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,4-dibutoxyphenylphosphine oxide , 1,10-Bis [bis (2,4,6-trimethylbenzoyl) phosphine oxide] decane, tri (2-methylbenzoyl) phosphine oxide, and the like.

The amount of the photopolymerization initiator used is not particularly limited, but is, for example, 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight, and more preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the monomer component. It is 1.5 parts by weight, more preferably 0.1 to 1 part by weight.

If the amount of the photopolymerization initiator used is less than 0.01 parts by weight, the polymerization reaction may be insufficient. If the amount of the photopolymerization initiator used exceeds 5 parts by weight, the photopolymerization initiator absorbs ultraviolet rays, so that the ultraviolet rays may not reach the inside of the pressure-sensitive adhesive layer. In this case, the polymerization rate is lowered or the molecular weight of the produced polymer is reduced. As a result, the cohesive force of the formed pressure-sensitive adhesive layer is lowered, and when the pressure-sensitive adhesive layer is peeled off from the film, a part of the pressure-sensitive adhesive layer remains on the film, and the film may not be reused. .. The photopolymerizable initiator may be used alone or in combination of two or more.

The weight average molecular weight of the (meth) acrylic polymer of the present invention is preferably 400,000 to 2.5 million, more preferably 600,000 to 2.2 million. By making the weight average molecular weight larger 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 2.5 million, the adhesiveness and adhesive strength tend to decrease. Further, the pressure-sensitive 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
(Meta) Acrylic polymer: GM7000H _XL + GMH _XL + GMH _XL
Aromatic polymer: G3000HXL + 2000HXL + G1000HXL
-Column size: 7.8 mmφ 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 volume: 100 μl
Eluent: Tetrahydrofuran Detector: Differential Refractometer Standard Sample: Polystyrene

The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B of the present invention may contain a cross-linking agent. Examples of the cross-linking agent include isocyanate-based cross-linking agent, epoxy-based cross-linking agent, silicone-based cross-linking agent, oxazoline-based cross-linking agent, aziridine-based cross-linking agent, silane-based cross-linking agent, alkyl etherified melamine-based cross-linking agent, metal chelate-based cross-linking agent, and excess Includes cross-linking agents such as oxides. The cross-linking agent may be used alone or in combination of two or more. As the cross-linking agent, an isocyanate-based cross-linking agent and an epoxy-based cross-linking agent 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 based on 100 parts by weight of the (meth) acrylic polymer. The cross-linking agent is preferably contained in the range of 0.01 to 5 parts by weight. The content of the cross-linking agent is preferably 0.01 to 4 parts by weight, more preferably 0.0 to 3 parts by weight.

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 (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name Coronate L), tri Isocyanate additives such as methylolpropane / hexamethylene diisocyanate trimeric adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name Coronate HL), isocyanurates of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name Coronate HX), xyl Trimethylol propane adduct of range isocyanate (manufactured by Mitsui Chemicals, trade name D110N), trimethylol propane adduct of hexamethylene diisocyanate (manufactured by Mitsui Chemicals, trade name D160N); polyether polyisocyanate, polyester polyisocyanate, and these. Examples thereof include additions of and various polyols, isocyanurate bonds, burette bonds, polyisocyanates functionalized by allophanate bonds and the like. Of these, it is preferable to use an aliphatic isocyanate because the reaction rate is high.

The isocyanate-based cross-linking agent may be used alone or in combination of two or more, but the content as a whole is 100 parts by weight of the (meth) acrylic polymer. On the other hand, the isocyanate-based cross-linking agent is preferably contained in an amount of 0.01 to 5 parts by weight, more preferably 0.01 to 4 parts by weight, and further preferably 0.02 to 3 parts by weight. .. It can be appropriately contained in consideration of cohesive force, prevention of peeling in durability test, and the like.

In the aqueous dispersion of the modified (meth) acrylic polymer prepared by emulsion polymerization, it is not necessary to use an isocyanate-based cross-linking agent, but if necessary, it is blocked because it easily reacts with water. An isocyanate-based cross-linking agent can also be used.

The epoxy-based cross-linking agent refers to a polyfunctional epoxy compound having two or more epoxy groups in one molecule. Examples of the epoxy-based cross-linking agent include bisphenol A, epichlorohydrin-type epoxy-based resin, N, N, N', N'-tetraglycidyl-m-xylene diamine, diglycidyl aniline, and 1,3-bis (N, N). -Diglycidyl aminomethyl) cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol Polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipate diglycidyl ester, o In addition to -phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, resorcin diglycidyl ether, bisphenol-S-diglycidyl ether, epoxy resins having two or more epoxy groups in the molecule, etc. Can be mentioned. Examples of the epoxy-based cross-linking agent include commercially available products manufactured by Mitsubishi Gas Chemical Company, Ltd., having trade names such as "Tetrad C" and "Tetrad X".

One type of the epoxy-based cross-linking agent may be used alone, or two or more types may be mixed and used, but the total content is 100 parts by weight of the (meth) acrylic polymer. On the other hand, the epoxy-based cross-linking agent is preferably contained in an amount of 0.01 to 5 parts by weight, more preferably 0.01 to 4 parts by weight, and further preferably 0.02 to 3 parts by weight. .. It can be appropriately contained in consideration of cohesive force, prevention of peeling in durability test, and the like.

As the peroxide cross-linking agent, any one that generates radically active species by heating to promote cross-linking of the base polymer of the pressure-sensitive adhesive can be appropriately used, but in consideration of workability and stability, 1 It is preferable to use a peroxide having a half-life temperature of 80 ° C. to 160 ° C., and more preferably to use a peroxide having a half-life temperature of 90 ° C. to 140 ° C.

Examples of the peroxide that can be used include di (2-ethylhexyl) peroxydicarbonate (1 minute half-life temperature: 90.6 ° C.) and di (4-t-butylcyclohexyl) peroxydicarbonate (1). Minute half-life temperature: 92.1 ° C., di-sec-butylperoxydicarbonate (1 minute half-life temperature: 92.4 ° C.), t-butylperoxyneodecanoate (1 minute half-life temperature: 103) .5 ° C), t-hexyl peroxypivalate (1 minute half-life temperature: 109.1 ° C), t-butyl peroxypivalate (1 minute half-life temperature: 110.3 ° C), dilauroyl peroxide (1 minute half-life temperature: 110.3 ° C) 1 minute half temperature: 116.4 ° C), di-n-octanoyl peroxide (1 minute half temperature: 117.4 ° C), 1,1,3,3-tetramethylbutylperoxy-2-ethyl Hexanoate (1 minute half-life temperature: 124.3 ° C.), di (4-methylbenzoyl) peroxide (1 minute half-life temperature: 128.2 ° C.), dibenzoyl peroxide (1 minute half-life temperature: 130. 0 ° C.), t-Butylperoxyisobutyrate (1 minute half-life temperature: 136.1 ° C.), 1,1-di (t-hexylperoxy) cyclohexane (1 minute half-life temperature: 149.2 ° C.) And so on. Among them, di (4-t-butylcyclohexyl) peroxydicarbonate (1 minute half-life temperature: 92.1 ° C.) and dilauroyl peroxide (1 minute half-life temperature: 116.) Since the cross-linking reaction efficiency is particularly excellent. 4 ° C.), dibenzoyl peroxide (1 minute half-life temperature: 130.0 ° C.) and the like are preferably used.

The half-life of peroxide is an index showing the decomposition rate of peroxide, and means the time until the residual amount of peroxide is halved. The decomposition temperature for obtaining a half-life at an arbitrary temperature and the half-life time at an arbitrary temperature are described in the manufacturer's catalog, etc. For example, "Organic peroxide catalog 9th edition" of Nippon Oil & Fats Co., Ltd. (May 2003) ”and so on.

One type of the peroxide may be used alone, or two or more types may be mixed and used, but the content as a whole is based on 100 parts by weight of the (meth) acrylic polymer. , The peroxide is 0.02 to 2 parts by weight, and preferably contains 0.05 to 1 part by weight. It is appropriately selected within this range in order to adjust workability, reworkability, crosslink stability, peelability and the like.

As a method for measuring the amount of peroxide decomposition remaining after the reaction treatment, for example, HPLC (high performance liquid chromatography) can be used.

More specifically, for example, about 0.2 g of the adhesive after the reaction treatment is taken out, immersed in 10 ml of ethyl acetate, extracted by shaking at 120 rpm for 3 hours at 25 ° C. with a shaker, and then 3 at room temperature. Let stand for a day. Next, 10 ml of acetonitrile was added, and the mixture was shaken at 120 rpm at 25 ° C. for 30 minutes, and about 10 μl of the extract obtained by filtering with a membrane filter (0.45 μm) was injected into HPLC for analysis, and after the reaction treatment. It can be the amount of peroxide.

Further, as the cross-linking agent, an organic cross-linking agent or a polyfunctional metal chelate may be used in combination. A polyfunctional metal chelate is one in which a polyvalent metal is covalently or coordinated to an organic compound. Examples of the polyvalent metal atom include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti and the like. Can be mentioned. Examples of the atom in the organic compound having a covalent bond or a coordination bond include an oxygen atom and the like, and examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound and a ketone compound.

The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B of the present invention can contain a polyfunctional monomer as a cross-linking agent. 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 exemplified as a monomer component forming a (meth) acrylic polymer. An example similar to that of

One type of polyfunctional monomer as a cross-linking agent may be used alone, or two or more types may be mixed and used, but the total content is the (meth) acrylic polymer 100. It is preferable that the cross-linking agent (polyfunctional monomer) is contained in the range of 0.001 to 5 parts by weight with respect to parts by weight. The content of the cross-linking agent (polyfunctional monomer) is preferably 0.005 to 3 parts by weight, more preferably 0.01 to 1 part by weight.

A photopolymerization initiator is blended in the pressure-sensitive adhesive containing the cross-linking agent (polyfunctional monomer). Examples of the photopolymerization initiator include those similar to those used for preparing the (meth) acrylic polymer. The amount of the photopolymerization initiator used is usually 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight, still more preferably 0.05, based on 100 parts by weight of the cross-linking agent (polyfunctional monomer). It is ~ 1.5 parts by weight, more preferably 0.1 to 1 part by weight. The pressure-sensitive adhesive containing the cross-linking agent (polyfunctional monomer) is cured by irradiation with active energy rays to form a pressure-sensitive adhesive layer (active energy ray-curable pressure-sensitive adhesive layer).

The multiple pressure-sensitive adhesive layer according to the pressure-sensitive adhesive layer A can form a predetermined thickness when at least one pressure-sensitive adhesive layer is an active energy ray-curable pressure-sensitive adhesive layer formed by irradiation with active energy rays. , Preferable from the viewpoint of step absorption. In particular, the first pressure-sensitive adhesive layer (a) and / or the second pressure-sensitive adhesive layer (b) is preferably an active energy ray-curable pressure-sensitive adhesive layer.

The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B of the present invention may contain a (meth) acrylic oligomer in order to improve the adhesive strength. As the (meth) acrylic oligomer, it is preferable to use a polymer having a higher Tg and a smaller weight average molecular weight than the (meth) acrylic polymer of the present invention. Such a (meth) acrylic oligomer has an advantage that it functions as a tackifier resin and increases the adhesive force without increasing the dielectric constant.

It is desirable that the Tg of the (meth) acrylic oligomer is about 0 ° C. or higher and 300 ° C. or lower, preferably about 20 ° C. or higher and 300 ° C. or lower, and more preferably about 40 ° C. or higher and 300 ° C. or lower. If the Tg is less than about 0 ° C., the cohesive force of the pressure-sensitive adhesive layer at room temperature or higher may decrease, and the holding characteristics and the adhesiveness at high temperatures may decrease. The Tg of the (meth) acrylic oligomer is a theoretical value calculated based on the Fox formula, like the Tg of the (meth) acrylic polymer.

The weight average molecular weight of the (meth) acrylic oligomer is 1000 or more and less than 30,000, preferably 1500 or more and less than 20000, and more preferably 2000 or more and less than 10000. If the weight average molecular weight is 30,000 or more, the effect of improving the adhesive strength may not be sufficiently obtained. On the other hand, if it is less than 1000, the molecular weight becomes low, which may cause deterioration of adhesive strength and holding characteristics. In the present invention, the weight average molecular weight of the (meth) acrylic oligomer can be determined by polystyrene conversion by the GPC method. Specifically, it is measured in HPLC 8020 manufactured by Tosoh Corporation using TSKgelGMH-H (20) × 2 as a column in a tetrahydrofuran solvent at a flow rate of about 0.5 ml / min.

Examples of the monomer constituting the (meth) acrylic oligomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, and isobutyl (meth) acrylate. , S-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, octyl. Alkyl such as (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate (Meta) acrylate; ester of (meth) acrylic acid such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate and alicyclic alcohol; phenyl (meth) acrylate, benzyl ( Aryl (meth) acrylates such as meta) acrylates; (meth) acrylates obtained from terpene compound derivative alcohols; and the like. Such (meth) acrylates can be used alone or in combination of two or more.

Examples of the (meth) acrylic oligomer include alkyl (meth) acrylates in which an alkyl group has a branched structure such as isobutyl (meth) acrylate and t-butyl (meth) acrylate; cyclohexyl (meth) acrylate and isobornyl (meth). Acrylate, ester of (meth) acrylic acid such as dicyclopentanyl (meth) acrylate and alicyclic alcohol; cyclic structure such as aryl (meth) acrylate such as phenyl (meth) acrylate and benzyl (meth) acrylate It is preferable that an acrylic monomer having a relatively bulky structure, typified by a (meth) acrylate having a resin, is contained as a monomer unit. By giving the (meth) acrylic oligomer such a bulky structure, the adhesiveness of the pressure-sensitive adhesive layer can be further improved. In particular, the one having a cyclic structure is highly effective in terms of bulkiness, and the one containing a plurality of rings is even more effective. Further, when ultraviolet rays are used when synthesizing a (meth) acrylic oligomer or when forming an adhesive layer, those having a saturated bond are preferable in that polymerization inhibition is unlikely to occur, and an alkyl group is preferable. An alkyl (meth) acrylate having a branched structure or an ester with an alicyclic alcohol can be preferably used as a monomer constituting the (meth) acrylic oligomer.

From this point of view, suitable (meth) acrylic oligomers include, for example, a copolymer of cyclohexyl methacrylate (CHMA) and isobutyl methacrylate (IBMA), and co-polymer of cyclohexyl methacrylate (CHMA) and isobornyl methacrylate (IBXMA). Polymers, cyclohexylmethacrylate (CHMA) and acryloylmorpholin (ACMO) copolymers, cyclohexylmethacrylate (CHMA) and diethylacrylamide (DEAA) copolymers, 1-adamantyl acrylate (ADA) and methylmethacrylate (MMA) co-polymers Polymers, dicyclopentanyl methacrylate (DCPMA) and isobornyl methacrylate (IBXMA) copolymers, cyclopentanyl methacrylate (DCPMA) and methyl methacrylate (MMA) copolymers, dicyclopentanyl methacrylate (DCPMA) , Cyclohexyl methacrylate (CHMA), isobornyl methacrylate (IBXMA), isobornyl acrylate (IBXA), dicyclopentanyl acrylate (DCPA), 1-adamantyl methacrylate (ADMA), 1-adamantyl acrylate (ADA) alone. Polymers and the like can be mentioned. In particular, an oligomer containing CHMA as a main component is preferable.

When the (meth) acrylic oligomer is used in the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B of the present invention, the content thereof is not particularly limited, but with respect to 100 parts by weight of the (meth) acrylic polymer. It is preferably 70 parts by weight or less, more preferably 1 to 70 parts by weight, further preferably 2 to 50 parts by weight, still more preferably 3 to 40 parts by weight. If the amount of the (meth) acrylic oligomer added exceeds 70 parts by weight, the elastic modulus becomes high and the adhesiveness at a low temperature deteriorates. When 1 part by weight or more of the (meth) acrylic oligomer is blended, it is effective from the viewpoint of improving the adhesive strength.

Further, the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B of the present invention has a silane cup in order to improve water resistance at the interface when applied to a hydrophilic adherend such as glass of the pressure-sensitive adhesive layer. It can contain a ring agent. The blending amount of the silane coupling agent is preferably 1 part by weight or less with respect to 100 parts by weight of the (meth) acrylic polymer, more preferably 0.01 to 1 part by weight, still more preferably 0.02 to 0. 6.6 parts by weight. If the amount of the silane coupling agent is too large, the adhesive force to the glass is increased and the removability is poor, and if the amount is too small, the durability is lowered, which is not preferable.

Preferred silane coupling agents include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxy). Epoxy group-containing silane coupling agents such as cyclohexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-( 1,3-Dimethylbutylidene) Amino group-containing silane coupling agents such as propylamine and N-phenyl-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, etc. Examples thereof include a (meth) acrylic group-containing silane coupling agent and an isocyanate group-containing silane coupling agent such as 3-isocyanatepropyltriethoxysilane.

Further, the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B of the present invention may contain other known additives, for example, a polyether compound of polyalkylene glycol such as polypropylene glycol, or coloring. Powders such as agents and pigments, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antioxidants, antioxidants, light stabilizers, UV absorbers, polymerization prohibited Agents, inorganic or organic fillers, metal powders, particulates, foils and the like can be added as appropriate depending on the intended use. Further, a redox system to which a reducing agent is added may be adopted within a controllable range.

The pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B can be formed, for example, by applying the forming material (adhesive) to a member such as a transparent substrate and / or a polarizing film and drying and removing a polymerization solvent or the like. .. When applying the forming material, one or more solvents other than the polymerization solvent may be newly added as appropriate.

Various methods are used as the coating method of the forming material. Specifically, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Examples include a method such as an extrusion coating method.

The heating and drying temperature is preferably 40 ° C. to 200 ° C., more preferably 50 ° C. to 180 ° C., and particularly preferably 70 ° C. to 170 ° C. By setting the heating temperature in the above range, the pressure-sensitive adhesive layer A or the pressure-sensitive adhesive layer B having excellent adhesive properties can be obtained. As the drying time, an appropriate time can be adopted as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

Further, when the forming material (adhesive) is an active energy ray-curable pressure-sensitive adhesive, the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B are polymerized by irradiating with active energy rays such as ultraviolet rays. It can be carried out. A high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, or the like can be used for ultraviolet irradiation.

Further, the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B can be formed on a support and then transferred to a polarizing film or the like. As the support, for example, a peeled sheet can be used. A silicone release liner is preferably used as the release-treated sheet. When the pressure-sensitive adhesive layer A is a multiple pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer A is formed by forming the first pressure-sensitive adhesive layer (a), the second pressure-sensitive adhesive layer (b), and the like in this order on the peeled sheet. The first pressure-sensitive adhesive layer (a), the second pressure-sensitive adhesive layer (b), etc., which may be bonded to a polarizing film or are individually formed, are provided so that the first pressure-sensitive adhesive layer (a) is on the outermost surface. , It can also be attached to the polarizing film in sequence.

Release-treated sheet can be used as a separator S B of the separator SA _1, the pressure-sensitive adhesive layer B of the adhesive layer A at (separator). In practical use, the peeled sheet is peeled off.

Examples of the constituent material of the separator include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film, porous materials such as paper, cloth, and non-woven fabrics, nets, foam sheets, metal foils, and laminates thereof. A thin leaf body can be mentioned, but a plastic film is preferably used because of its excellent surface smoothness.

The plastic film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer A or the pressure-sensitive adhesive layer B, and is, for example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, or a polychloride. Examples thereof include vinyl film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film and the like.

For the separator, the plastic film is used as a base film, and if necessary, a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based mold release agent, silica powder, or the like is used for mold release and antifouling treatment. Also, antistatic treatment such as coating type, kneading type, and vapor deposition type can be performed. In particular, the peelability from the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B 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 separator.

Examples of the silicone-based release layer include an addition reaction type silicone resin. For example, Shin-Etsu Chemical KS-774, KS-775, KS-778, KS-779H, KS-847H, KS-847T, Toshiba Silicone TPR-6700, TPR-6710, TPR-6721, Toray Dow Corning SD7220, SD7226 and the like. The coating amount of the silicone-based release layer (after drying) of 0.01 to 2 g / ^{m 2,} preferably from 0.01 to 1 g / ^{m 2,} still more preferably in the range of 0.01 to 0.5 g / ^{m 2} ..

To form the release layer, for example, the above material is applied onto the oligomer-preventing layer by a conventionally known coating method such as reverse gravure coating, bar coating, die coating, and then heat treatment is usually performed at about 120 to 200 ° C. It can be done by curing by applying. Further, if necessary, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination.

The thickness of the separator (including the release layer) is usually about 5 to 200 μm. Since the thickness of the separator is related to the peeling force, it is preferable to adopt a thickness corresponding to the separator. The thicknesses of the separators SA ₁ , SA ₁ ′, and SA ₂ are all preferably 30 μm or more, more preferably 40 μm or more, and further preferably 50 μm or more from the viewpoint of peeling force and prevention of dents. Specifically, the separator _{SA 1,} SA 1 ', the thickness is preferably 40~130μm SA _2, further 50~80μm is preferred. The thickness of the separator SB is preferably 10 to 80 μm, preferably 20 to 50 μm, more preferably 30 to 50 μm, and further preferably 30 to 40 μm. Further, in the configuration of the polarizing film with the double-sided pressure-sensitive adhesive layer, the thickness of the separator is a combination of the case where the thickness of the separator SA ₁ (SA ₁ ′) is 50 μm or more and the case where the thickness of the separator SB is 30 to 50 μm. This is particularly preferable from the viewpoint of peeling force and prevention of dents.

Further, when the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B are provided on the polarizing film, the surface of the polarizing film can be easily adhered. Examples of the easy-adhesion treatment include corona treatment, plasma treatment, excimer treatment, hard coating treatment, and undercoat treatment. Further, the surface of the pressure-sensitive adhesive layer may be subjected to an easy-adhesion treatment. In the polarizing film with a pressure-sensitive adhesive layer of the present invention, it is preferable that the surface of the polarizing film on which the pressure-sensitive adhesive layer A is laminated is easily adhered and peeled off from the viewpoint of suppressing foaming.

Further, the polarizing film with an adhesive layer of the present invention can be prepared so that any portion has an antistatic function. The antistatic function can be imparted to the polarizing film with an adhesive layer, for example, by incorporating an antistatic agent in the polarizing film or the pressure-sensitive adhesive layer, or by providing an antistatic layer separately.

In the polarizing film with an adhesive layer of the present invention, the antistatic layer is arranged on the viewing side of the polarizing film used in an image display device (for example, a liquid crystal display device) with respect to the polarizing film provided on the most visible side. Can be done. Therefore, there are problems such as depolarization that may occur when an antistatic layer (low surface resistance layer) is provided between the polarizing film on the viewing side and the liquid crystal panel, and deterioration of optical characteristics such as generation of bright spots due to impurities. It can be significantly reduced and does not impair the reliability of the polarizing film provided on the most visible side. In this way, the antistatic function can be imparted without impairing the performance of the image display device.

In particular, it is effective when applied to a liquid crystal display device having a built-in touch sensor such as an in-cell type or an on-cell type, and can improve the quality of a liquid crystal display device having a built-in touch sensor such as an in-cell type or an on-cell type.

In order to impart an antistatic function to the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B of the present invention, an ionic compound can be contained as an antistatic agent in addition to the base polymer. As the ionic compound, an alkali metal salt and / or an organic cation-anionic salt can be preferably used. As the alkali metal salt, an organic salt and an inorganic salt of the alkali metal can be used. The term "organic cation-anionic salt" as used in the present invention refers to an organic salt whose cation portion is composed of an organic substance, and the anion portion may be an organic substance or an inorganic substance. There may be. The "organic cation-anionic salt" is also referred to as an ionic liquid or an ionic solid.

Examples of the ionic compound include inorganic salts such as ammonium chloride, aluminum chloride, copper chloride, ferric chloride, ferric chloride and ammonium sulfate, in addition to the above-mentioned alkali metal salt and organic cation-anionic salt. .. These ionic compounds can be used alone or in combination of two or more.

The ratio of the ionic compound in the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer A and the pressure-sensitive adhesive layer B of the present invention is preferably 0.0001 to 5 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer. If the amount of the ionic compound is less than 0.0001 parts by weight, the effect of improving the antistatic performance may not be sufficient. The ionic compound is preferably 0.01 part by weight or more, and more preferably 0.1 part by weight or more. On the other hand, if the amount of the ionic compound is more than 5 parts by weight, the durability may not be sufficient. The ionic compound is preferably 3 parts by weight or less, and more preferably 1 part by weight or less. The ratio of the ionic compound can be set in a preferable range by adopting the upper limit value or the lower limit value.

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. The evaluation items in the examples and the like were measured as follows.

<Creation of polarizing film>
A polyvinyl alcohol film having a thickness of 80 μm was dyed between rolls having different speed ratios in an iodine solution at 30 ° C. and a concentration of 0.3% for 1 minute, and stretched up to 3 times. Then, the total stretching ratio was stretched to 6 times while being immersed in an aqueous solution containing boric acid having a concentration of 4% and potassium iodide having a concentration of 10% at 60 ° C. for 0.5 minutes. Then, it was washed by immersing it in an aqueous solution containing potassium iodide having a concentration of 1.5% at 30 ° C. for 10 seconds, and then dried at 50 ° C. for 4 minutes to obtain a polarizer having a thickness of 20 μm. A saponified 40 μm-thick triacetyl cellulose film was bonded to one side of the polarizing element, and a 20 μm-thick acrylic film was bonded to the other side with a polyvinyl alcohol-based adhesive to prepare a polarizing film. .. The surface (triacetyl cellulose film side) to which the pressure-sensitive adhesive layer B of the polarizing film is bonded was appropriately subjected to corona treatment.

<Separator SA ₁ >
A release film provided with the following release layer was used on a polyethylene terephthalate film having a thickness of 38 μm, 50 μm or 75 μm.

<Separator SA ₁ '>
A release film provided with the following release layer was used for a polyethylene terephthalate film having a thickness of 50 μm.

<Separator SA ₂ >
A release film provided with the following release layer was used for a polyethylene terephthalate film having a thickness of 50 μm.

<Separator SB>
A release film provided with the following release layer was used on a polyethylene terephthalate film having a thickness of 38 μm, 50 μm or 75 μm.

≪Formation of release layer≫
The following release layer was formed on each of the separators.
Silicone resin (KS-847H: manufactured by Shin-Etsu Chemical): 20 parts by weight and curing agent (PL-50T: manufactured by Shin-Etsu Chemical): 0.2 parts by weight, 350 parts by weight of methyl ethyl ketone / toluene mixed solvent (mixing ratio 1: 1) A solution of a silicone-based release agent was prepared by diluting with parts. The solution of the silicone release agent is applied to each of the above polyethylene terephthalate films (base film) with a gravure coater so that the thickness after drying becomes 100 nm, and then dried at 120 ° C. to form a release layer. It was formed to obtain a separator having a base film / release layer structure.

Manufacturing example 1
<Preparation of material for forming adhesive layer A>
70 parts of 2-ethylhexyl acrylate (2EHA), 15 parts of N-vinylpyrrolidone (NVP), 4-hydroxybutyl acrylate (4HBA) in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler. A four-necked flask containing 15 parts, 2 types of photopolymerization initiators (trade name: Irgacure 184, manufactured by BASF) and 0.05 parts and photopolymerization initiators (trade name: Irgacure 651, manufactured by BASF). To prepare a monomer mixture. Then, the monomer mixture was exposed to ultraviolet rays in a nitrogen atmosphere and partially photopolymerized to obtain a partial polymer (acrylic polymer syrup) having a polymerization rate of about 10%.

Next, 0.01 part of trimethylolpropane triacrylate (TMPTA) was added to 100 parts of the above-mentioned acrylic polymer syrup, and then these were uniformly mixed to form a material for forming the pressure-sensitive adhesive layer A (monomer component: A1). ) Was prepared.

Production Examples 2-5
In Production Example 1, the same operation as in Production Example 1 was performed except that the composition of each component used for preparing the monomer component was changed as shown in Table 1, and the material for forming the pressure-sensitive adhesive layer A (monomer component: A2 to A5) were prepared.

表１中、２ＥＨＡは、２−エチルヘキシルアクリレート；
ＮＶＰは、Ｎ−ビニルピロリドン；
４ＨＢＡは、４−ヒドロキシブチルアクリレート；
ＴＭＰＴＡは、トリメチロールプロパントリアクリレート；を示す。

In Table 1, 2EHA is 2-ethylhexyl acrylate;
NVP is N-vinylpyrrolidone;
4HBA is 4-hydroxybutyl acrylate;
TMPTA indicates trimethylolpropane triacrylate;

<Creation of adhesive layer A with separators on both sides>
The final thickness of the material (monomer component) for forming the pressure-sensitive adhesive layer A prepared in the above production example is 50 μm, 100 μm, 200 μm or 300 μm on the release-treated surface of the separator SA ₁ shown in Table 2 or Table 3. Was applied to form a coating layer. Next, the surface of the coated monomer component was coated with the separator SA ₂ shown in Table 2 or Table 3 so that the release-treated surface of the film was on the coating layer side. As a result, the coating layer of the monomer component was shielded from oxygen. The sheet having the coating layer thus obtained is exposed to ultraviolet rays having an illuminance of 5 mW / cm ² (measured with Topcon UVR-T1 having the maximum sensitivity at about 350 nm) for 360 seconds using a chemical light lamp (manufactured by Toshiba Corporation). By irradiating, the coating layer was cured to form the pressure-sensitive adhesive layer A, and the pressure-sensitive adhesive layer A with a separator on both sides was prepared.

<Preparation of adhesive forming adhesive layer B>
In a separable flask equipped with a thermometer, stirrer, reflux cooling tube and nitrogen gas introduction tube, 99 parts of butyl acrylate (BA) and 1 part of 4-hydroxybutyl acrylate (4HBA) as monomer components, and azobis as a polymerization initiator. After adding 0.2 part of isobutyronitrile and ethyl acetate as a polymerization solvent so that the solid content became 30%, nitrogen gas was flowed and nitrogen substitution was carried out for about 1 hour with stirring. Then, the flask was heated to 60 ° C. and reacted for 7 hours to obtain an acrylic polymer having a weight average molecular weight (Mw) of 1.1 million. To the above acrylic polymer solution (solid content 100 parts), 0.1 part of trimethylolpropane xylylene diisocyanate (manufactured by Mitsui Chemicals, Inc., "Takenate D110N") as an isocyanate-based cross-linking agent, and a silane coupling agent (Shin-Etsu Chemical Co., Ltd. A pressure-sensitive adhesive composition (solution) was prepared by adding 0.1 part of "KBM-403") manufactured by Co., Ltd.

<Creation of adhesive layer B with separator>
The prepared pressure-sensitive adhesive solution was applied to the release-treated surface of the separator SB shown in Table 2 or Table 3 so that the thickness after drying was 20 μm, and under normal pressure, 60 ° C. for 3 minutes and 120 ° C. for 3 minutes. The adhesive layer B was prepared by heating and drying for 1 minute and further aging at 23 ° C. for 120 hours.

<Creation of polarizing film with adhesive layer B on one side>
The pressure-sensitive adhesive layer B with the separator SB was transferred to one side (triacetyl cellulose film side) of the polarizing film to prepare a polarizing film with the pressure-sensitive adhesive layer B on one side.

Example 1
<Creation of polarizing film with double-sided adhesive layer>
An apparatus as shown in FIG. 6 was used.
The pressure-sensitive adhesive layer A with the separators on both sides was conveyed from the delivery roll, and the separator SA ₂ was peeled off by the release roll to convey the pressure-sensitive adhesive layer A with the separator SA ₁ . On the other hand, separately, the pressure-sensitive adhesive layer A with the separator SA _{1 is} bonded to the polarizing film side (acrylic film side) of the polarizing film with the pressure-sensitive adhesive layer B on one side, which is conveyed from the delivery roll, by a pair of rolls. , A polarizing film with a double-sided adhesive layer was prepared by roll-to-roll. Further, in the bonding, the tension T1 of the pressure-sensitive adhesive layer A with a one-sided separator and the tension T2 of the polarizing film with the one-sided pressure-sensitive adhesive layer B were controlled as shown in Table 2.

In the creation of the double-sided pressure-sensitive adhesive layer-attached polarizing film, a separator SA _1, separator SA _2, the thickness of the separator SB, peel force _{a 1} of the separator SA _1, peel strength _{a 2} separators SA _2, peel strength b of the separator SB is , As shown in Table 1.
The surface (triacetyl cellulose film side) to which the pressure-sensitive adhesive layer B of the polarizing film was bonded was corona-treated.
The thickness of the pressure-sensitive adhesive layer A is as shown in Table 1.

<Measurement of tension>
The stress converted to 1 m width was measured using a detection roll equipped with an MB tension sensor manufactured by Nireco Corporation.

Examples 2 to 13, Comparative Examples 1 to 5
In Example 1, the thickness of the separator SA ₁ , the separator SA ₂ , and the separator SB,
Peel force _{a 1} of the separator SA _1, peel strength _{a 2} separators SA _2, the release force of the separator SB b,
Thickness of adhesive layer A, storage elastic modulus of adhesive layer A (type of adhesive),
Presence or absence of corona treatment on the surface to which the adhesive layer A of the polarizing film is bonded,
The same operation as in Example 1 was performed except that the tension T1 of the pressure-sensitive adhesive layer A with one-sided separator and the tension T2 of the polarizing film with one-sided pressure-sensitive adhesive layer B were changed as shown in Table 1, and the double-sided pressure-sensitive adhesive layer was performed. A polarizing film with an adhesive was prepared.
In Comparative Examples 1 and 2, instead of roll-to-roll, a polarizing film with a one-sided pressure-sensitive adhesive layer B prepared for each and a pressure-sensitive adhesive layer A with a separator SA ₁ were bonded to a single-wafer film manufactured by Suntech. With the absorption shaft as the long side, they were bonded together with an area of 500 mm × 400 mm.

Example 14
<Creation of polarizing film with double-sided adhesive layer>
An apparatus as shown in FIG. 7 was used.
The polarizing film with a double-sided pressure-sensitive adhesive layer obtained in Comparative Example 3 was conveyed from a feeding roll, and the separator SA ₁ was peeled off by a peeling roll, and the polarized light with a double-sided pressure-sensitive adhesive layer from which the separator SA ₁ was peeled off. The film was conveyed.
On the other hand, separately, the curl adjusting separator SA ₁ ′ conveyed from the delivery roll is bonded to the pressure-sensitive adhesive layer A of the polarizing film with the double-sided pressure-sensitive adhesive layer by a pair of rolls, and the double-sided pressure-sensitive adhesive is rolled to roll. A layered polarizing film was prepared. Also, the time of bonding, the tension T4 tension T3 and the separator SA ₁ is attached polarizing film sided pressure-sensitive adhesive layer is peeled of the curl adjustment separator SA 1 _', while controlling as shown in Table 3 subjected It was.

In the above polarizing film with double-sided pressure-sensitive adhesive layer, _'the thickness of the separator SA _1' separator SA 1 peel force a ₁ of _'are shown in the description of Table 3.

Comparative Example 6
In Example 14, a polarizing film with a double-sided pressure-sensitive adhesive layer conveyed from a delivery roll (Comparative Example 3 was changed to Example 2), tension T3 of the curl adjusting separator SA ₁ ′ and both sides from which the separator SA ₁ was peeled off. The same operation as in Example 14 was performed except that the tension T4 of the polarizing film with an adhesive layer was changed as shown in Table 3, to prepare a polarizing film with a double-sided adhesive layer.

The following evaluations were performed on the polarizing films with the double-sided pressure-sensitive adhesive layer obtained in the above-mentioned production examples, examples and comparative examples. The evaluation results are shown in Table 1.

<Measurement of shear storage elastic modulus>
The shear storage elastic modulus at 23 ° C. was determined by dynamic viscoelasticity measurement. The above measurement samples (adhesive layer A, adhesive layer B) were subjected to a dynamic viscoelasticity measuring device (device name “ARES”, manufactured by TA Instruments) under the condition of a frequency of 1 Hz. The shear storage elastic modulus at 23 ° C. was calculated by measuring at a temperature range of -20 to 100 ° C. and a heating rate of 5 ° C./min.

<Measurement of separator peeling force>
After cutting the measurement sample with a separator (peeling liner) (adhesive layer A with separator, adhesive layer B with separator) into a width of 50 mm and a length of 100 mm, the separator (peeling liner) is pulled from the sample by a tensile tester. The peeling force (N / 50 mm) at the time of peeling was measured at a peeling angle of 180 ° and a peeling speed of 300 mm / min.

<Curl>
The polarizing film with a double-sided pressure-sensitive adhesive layer is a rectangular object cut out 300 mm in the absorption axis direction of the polarizing film and 250 mm in the direction orthogonal to the absorption axis, on a horizontal plane so that the surface having a convex curl is on the lower side. The distance (mm) of the longest point from the horizontal plane was measured among the four points of the corner.

<Yield>
For a polarizing film with a double-sided adhesive layer (size: 70 mm × 100 mm), after peeling off the separator SB, the side of the adhesive layer B was attached to a 0.7 mm-thick non-alkali glass (1737, manufactured by Corning Inc.). .. This operation was performed 10 times.
Then, in the bonding operation, it was confirmed whether or not the bonding operation could be completed without the occurrence of bubble biting at the end portion. The rate (success rate) when air bubble biting does not occur at the end is shown by the following criteria.
⊚: Success rate 100%.
〇: Success rate is less than 80-100%.
Δ: Success rate is less than 50-80%.
X: Success rate is less than 50%.

<Evaluation method of step absorption>
A sheet piece having a width of 50 mm and a length of 100 mm was cut out from the pressure-sensitive adhesive layer A with separators on both sides. One of the release films was peeled off from the sheet piece, and the pressure-sensitive adhesive layer side of the sheet piece was attached to a COP (cyclic polyolefin) film (thickness: 100 μm) using a hand roller.
Next, the other release film was peeled off from the sheet piece bonded to the COP film. The glass plate with a printing step was bonded under the following bonding conditions so that the surface of the glass plate having the printing step and the adhesive layer on the COP film were in contact with each other. Then, an evaluation sample having a composition of COP film / adhesive layer / glass plate with printing step was obtained.
(Bating conditions)
Surface pressure: 0.3 MPa
Pasting speed: 25 mm / s
Roll rubber hardness: 70 °
The glass plate with a printing step is the thickness of the printed portion (height of the printing step) on one surface of the glass plate (manufactured by Matsunami Glass Industry Co., Ltd., length 100 mm, width 50 mm, thickness 0.7 mm). ) Used a glass plate printed with 50 μm or 80 μm.
(Step / thickness of adhesive layer) × 100 (%), which is an index showing step absorbency, is 50% and 80%, respectively.
Next, the evaluation sample was put into an autoclave and autoclaved for 15 minutes under the conditions of a pressure of 5 atm and a temperature of 50 ° C. After the autoclave treatment, an evaluation sample was taken out, the state of adhesion between the adhesive layer and the glass plate with a printing step was visually observed, and the step absorption was evaluated according to the following evaluation criteria.
◯: No air bubbles remain, and no floating occurs between the adhesive layer and the glass plate with a printing step.
X: There are air bubbles remaining, and floating occurs between the adhesive layer and the glass plate with a printing step.

<Durability>
Peel off the separator film of the adhesive layer A (visual side) of the polarizing film with the adhesive layer obtained in each of the above examples, and attach it to a 0.7 mm thick non-alkali glass (1737 manufactured by Corning Inc.) using a laminator. I wore it. Next, an autoclave treatment was performed at 50 ° C. and 0.5 MPa for 15 minutes to completely adhere the polarizing film with the pressure-sensitive adhesive layer to the non-alkali glass. Next, vacuum bonding was performed using a vacuum bonding device manufactured by LANTECH under the conditions of a pressure of 0.2 MPa and a vacuum degree of 30 Pa. This was put under the conditions of a heating oven (heating) at 85 ° C. and 95 ° C. and a constant temperature / humidifier (humidifying) at 60 ° C./95% RH, respectively, and the presence or absence of peeling of the polarizing film after 500 hours was checked. It was evaluated according to the following criteria.
⊚: No peeling was observed.
◯: Peeling that could not be visually confirmed was observed.
Δ: Small peeling that can be visually confirmed was observed.
X: Clear peeling (more than 0.5 μm) was observed.

比較例５の歩留まりの結果「気泡有」は、粘着剤層Ａの貯蔵弾性率が高いため、カバーガラスを貼り合せた後、カバーガラスのインク段差を埋めきれずに貼り合せ直後に気泡が発生していることを示す。

As a result of the yield of Comparative Example 5, "with bubbles" has a high storage elastic modulus of the adhesive layer A, so that after the cover glass is bonded, the ink step of the cover glass cannot be filled and bubbles are generated immediately after the bonding. Show that you are doing.

比較例６は、貼り代えにより、特定が低下した場合である。

Comparative Example 6 is a case where the specificity is lowered due to the replacement.

1 Polarizing film A Adhesive layer A (visual side)
B Adhesive layer B (opposite to the visible side)
C member (touch panel or transparent substrate)
D display unit (image display device)
SA ₁ opposite separator SA ₁ 'pressure-sensitive adhesive layer A separator SB adhesive layer B (viewing side of the curl adjusting separator SA ₂ pressure-sensitive adhesive layer A of (viewing side) (viewing side) of the pressure-sensitive adhesive layer A (viewing side) (Side) Separator 10, 10'Polarizing film with double-sided adhesive layer 11 Adhesive layer A with one-sided separator
12 Polarizing film with adhesive layer B on one side 13 Polarizing film with double-sided adhesive layer from which separator SA ₁ has been peeled off 14 Adhesive layer A with adhesive layer on both sides
2 Adhesive layer (adhesive layer B)
3 Transparent conductive layer (antistatic layer)
4 Glass substrate 5 Liquid crystal layer 6 Drive electrode 7 Antistatic layer and sensor layer 8 Drive electrode and sensor layer 9 Sensor layer a First adhesive layer b Second adhesive layer

Claims (11)

A polarizing film provided on the most visible side of a polarizing film used in an image display device, an adhesive layer A arranged on the visible side of the polarizing film, and an adhesive layer B arranged on the opposite side of the adhesive layer A. A polarizing film with a double-sided pressure-sensitive adhesive layer, which has a separator SA _{1 on} the pressure-sensitive adhesive layer A and a separator SB on the pressure-sensitive adhesive layer B.
The pressure-sensitive adhesive layer A has a storage elastic modulus at 23 ° C. of 0.02 to 0.3 MPa.
The peel force _{a 1} of the separator SA ₁ is higher than the peel strength b of the separator SB,
The polarizing film with a double-sided pressure-sensitive adhesive layer is a rectangular object cut out of 300 mm in the absorption axis direction and 250 mm in the direction perpendicular to the absorption axis of the polarizing film so that the surface having a convex curl is on the lower side. Curl amount measured by placing it on a horizontal plane (however, the curl amount measured by placing it on a horizontal plane so that the side of the separator SB is on the lower side is +, and the curl amount measured by placing it on the horizontal plane is +, and the horizontal plane is such that the side of the separator SA ₁ is on the lower side. A polarizing film with a double-sided pressure-sensitive adhesive layer, wherein the amount of curl measured on the top is displayed as-), which is -10 mm to +60 mm. The polarizing film with a double-sided pressure-sensitive adhesive layer according to claim 1, wherein the curl amount is +2 mm to +30 mm. The polarizing film with a double-sided pressure-sensitive adhesive layer according to claim 1 or 2, wherein the separator SA ₁ has a thickness of 50 μm or more, and the separator SB has a thickness of 30 to 55 μm. The method for producing a polarizing film with a double-sided pressure-sensitive adhesive layer according to any one of claims 1 to 3 .
A polarizing film with a one-sided pressure-sensitive adhesive layer B having a polarizing film and a pressure-sensitive adhesive layer B provided on the most visible side of the polarizing film used in an image display device and having a separator SB on the pressure-sensitive adhesive layer B.
A pressure-sensitive adhesive layer A with a one-sided separator having a pressure-sensitive adhesive layer A having a storage elastic modulus of 0.02 to 0.3 MPa at 23 ° C. on the separator SA ₁ .
The roll-toe so that the pressure-sensitive adhesive layer A of the pressure-sensitive adhesive layer A with a one-sided separator is arranged on the polarizing film on the opposite side of the polarizing film with the pressure-sensitive adhesive layer B on the one-sided side where the pressure-sensitive adhesive layer B is provided. A method for producing a polarizing film with a double-sided pressure-sensitive adhesive layer, which comprises a step (1) of bonding with a roll. The pressure-sensitive adhesive layer A with a one-sided separator is a step of peeling the separator SA ₂ from the pressure-sensitive adhesive layer A with a double-sided separator having the separator SA ₁ on one side of the pressure-sensitive adhesive layer A and the separator SA ₂ on the other side (a). ), And
Claims wherein the peel force _{a 1} of the separator SA _1, peel strength _{a 2} of the separator SA _2, and peel strength b of the separator SB _is characterized by satisfying the a 1> _{a 2} ≧ b, the relationship 4. The method for producing a polarizing film with a double-sided pressure-sensitive adhesive layer. Wherein the peel force _{a 1} of the separator SA _1, peel strength _{a 2} of the separator SA _2, and peel strength b of the separator SB _is, satisfies a 1> 1.5a ₂ ≧ 1.5b, the relationship The method for producing a polarizing film with a double-sided pressure-sensitive adhesive layer according to claim 5 . In the step (1) of laminating by roll-to-roll,
6. Of claims 4 to 6 , wherein the ratio (T1 / T2) of the tension T1 of the pressure-sensitive adhesive layer A with one-sided separator and the tension T2 of the polarizing film with one-sided pressure-sensitive adhesive layer B is controlled to 0.8 or more. The method for producing a polarizing film with a double-sided pressure-sensitive adhesive layer according to any one. Following the method for producing a polarizing film with a double-sided pressure-sensitive adhesive layer according to any one of claims 4 to 6 .
The step (b) of peeling the separator SA ₁ from the obtained polarizing film with a double-sided pressure-sensitive adhesive layer, and
4. The fourth aspect of the present invention includes a step (2) of attaching the curl adjusting separator SA ₁ ′ to the adhesive layer A of the polarizing film with the double-sided adhesive layer from which the separator SA ₁ has been peeled off by roll-to-roll. The method for producing a polarizing film with a double-sided pressure-sensitive adhesive layer according to any one of 6 to 6 . In the step (2) of laminating by roll-to-roll,
And wherein the ratio of the tension T4 tension T3 and the separator SA ₁ is attached polarizing film sided pressure-sensitive adhesive layer is peeled curl adjustment separator SA 1 _'(T3 / T4) is controlled to 0.8 or more The method for producing a polarizing film with a double-sided pressure-sensitive adhesive layer according to claim 8 . Following the method for producing a polarizing film with a double-sided pressure-sensitive adhesive layer according to any one of claims 4 to 9 .
It is characterized by including a step (c) of cutting the obtained polarizing film with a double-sided adhesive layer to an arbitrary size and a step (d) of cutting an end portion of the cut polarizing film with a double-sided adhesive layer. The method for producing a polarizing film with a double-sided pressure-sensitive adhesive layer according to any one of claims 4 to 9 . An image display device having at least one polarizing film with a double-sided adhesive layer.
The polarizing film with a double-sided pressure-sensitive adhesive layer provided on the most visible side of the polarizing film used in the image display device is the separator SA ₁ and the separator from the polarizing film with the double-sided pressure-sensitive adhesive layer according to any one of claims 1 to 3. SB is removed,
An image display device characterized in that the pressure-sensitive adhesive layer A of the polarizing film with a double-sided pressure-sensitive adhesive layer is arranged on the viewing side and the pressure-sensitive adhesive layer B is arranged on the display portion side.

Images