JP7311014B1 - Adhesive sheet rolls and adhesive sheets - Google Patents

Abstract

A pressure-sensitive adhesive sheet roll for a flexible display having excellent quality is provided.
The adhesive sheet roll is an adhesive sheet roll 10 in which a long adhesive sheet 3 is wound around a core. The adhesive sheet 3 has an adhesive layer 7 with a thickness of 5 to 150 μm sandwiched between a light release sheet 8 and a heavy release sheet 6. When the release sheet 8 was peeled off, the peel force Pl was 0.02 to 0.30 N/25 mm. The release force Ph at the time is 0.10 to 0.80 N / 25 mm, Ph / Pl is 2 to 6, the thickness Tl of the light release sheet and the thickness Th of the heavy release sheet are specified within a specific range, and the roll outer side is light. Make a release sheet.
[Selection drawing] Fig. 1

Description

The present disclosure relates to a pressure-sensitive adhesive sheet roll and a pressure-sensitive adhesive sheet having substrate-less double-sided pressure-sensitive adhesive layers.

A substrate-less double-sided pressure-sensitive adhesive sheet is known. Such a double-faced PSA sheet is used for bonding adherends, and usually has an adhesive layer sandwiched between release sheets. Such an adhesive sheet is sometimes produced as an adhesive sheet roll wound around a core in order to improve productivity, in addition to being produced in the form of a sheet.

Patent Documents 1 and 2 disclose a first release sheet/adhesive layer having a specific range of shear storage elastic modulus at 120° C./ A roll-shaped pressure-sensitive adhesive sheet is disclosed which is formed by winding a laminated sheet of a second release sheet into a roll and has a roll hardness within a specific range.

2. Description of the Related Art In recent years, the development of techniques for increasing the screen size of a display while maintaining the size of the device has been actively promoted. For example, there are foldable displays and rollable displays. The former is a foldable display that can be freely opened and closed, and the latter is a display that can be rolled up. Such adhesive layers for flexible displays are required to have flexibility and restorability in addition to the properties conventionally required for adhesive layers.

Japanese Patent Application Laid-Open No. 2021-1272 Japanese Patent Application Laid-Open No. 2021-1273

From the standpoint of productivity, the substrate-less double-sided PSA sheet is in demand in the market in the form of a PSA sheet roll. However, in the roll form, tension is applied to the pressure-sensitive adhesive sheet, which causes problems such as deformation of the pressure-sensitive adhesive layer due to contamination of foreign matters such as dust and dirt, and dents in the pressure-sensitive adhesive layer. In addition, due to the tension of the pressure-sensitive adhesive sheet in the form of a roll, or during unwinding from the roll, a tunneling phenomenon occurs in which peeling or floating (bubbles) occurs between the release sheet and the pressure-sensitive adhesive layer, leaving traces of peeling on the pressure-sensitive adhesive layer. There is a problem.

Deformation, denting, or tunneling of the adhesive layer may reduce the adhesion between the adhesive layer and the adherend. Moreover, when the adhesive layer is used for attaching a display member, the image quality may deteriorate. Such problems are particularly serious in adhesive layers designed with flexibility and resilience in mind for application to flexible devices.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide an adhesive sheet roll and an adhesive sheet for a flexible display with excellent quality.

The present disclosure provides the following adhesive sheet roll and adhesive sheet.
[1]: A pressure-sensitive adhesive sheet roll in which a long pressure-sensitive adhesive sheet is wound around a core,
The adhesive sheet has an adhesive layer with a thickness of 5 to 150 μm sandwiched between a light release sheet and a heavy release sheet,
In the adhesive sheet unwound from the adhesive sheet roll, the peel strength when the light release sheet is peeled from the adhesive layer at a peel angle of 180 ° and a peel speed of 300 mm / min in an environment of 23 ° C. and 50% relative humidity. Pl is 0.02 to 0.30 N / 25 mm,
After peeling the light release sheet from the adhesive layer, a 50 μm PET film is attached to the exposed adhesive layer, and the heavy release sheet is further removed from the adhesive layer at 23 ° C. and a relative humidity of 50%. The peel force Ph when peeled at 180 ° and the peel speed of 300 mm / min is 0.10 to 0.80 N / 25 mm,
Ph/Pl is 2 to 6,
The thickness Tl of the light release sheet is 25 to 100 μm,
The thickness Th of the heavy release sheet is 50 to 188 μm,
and the Tl < the Th,
A pressure-sensitive adhesive sheet roll for a flexible display, wherein the light release sheet is provided on the outer side of the roll.
[2]: The pressure-sensitive adhesive sheet roll according to [1], wherein the standard deviation σ of the thickness of the pressure-sensitive adhesive sheet is 10% or less with respect to the layer thickness.
[3]: The adhesive layer is
A gel fraction of 50 to 90% and a storage modulus at -30°C of 10 MPa or less,
A pressure-sensitive adhesive layer containing a pressure-sensitive adhesive resin having a weight average molecular weight of 500,000 or more,
The adhesive resin contains a (meth)acrylic copolymer (a),
The (meth)acrylic copolymer (a) is a linear or branched alkyl (meth) having a structural unit derived from an alicyclic (meth)acrylate monomer and/or an alkyl group having 8 to 20 carbon atoms. ) The pressure-sensitive adhesive sheet roll according to [1] or [2], which is a copolymer having structural units derived from acrylate monomers.
[4]: A pressure-sensitive adhesive sheet for a flexible display obtained by unwinding from the pressure-sensitive adhesive sheet roll according to any one of [1] to [3] and punching.

ADVANTAGE OF THE INVENTION According to this indication, the outstanding effect of being able to provide the pressure sensitive adhesive sheet roll for flexible displays and the pressure sensitive adhesive sheet which were excellent in quality is produced.

1 is a schematic perspective view showing an example of an adhesive sheet roll according to an embodiment; FIG. II-II section sectional drawing of FIG.

The present disclosure will be described in detail below. It goes without saying that other embodiments are also included in the scope of the present disclosure as long as they match the gist of the present disclosure. In addition, in this specification, the numerical range specified using "-" shall include the numerical values described before and after "-" as the range of lower and upper values. Moreover, in this specification, the terms "film", "sheet" and "tape" have the same meaning and are not distinguished by thickness or shape. (Meth)acrylic means acrylic or methacrylic. In addition, unless otherwise noted, the various components appearing in the present specification may be used singly or in combination of two or more. Numerical values specified in this specification refer to values obtained by methods described in Examples.

1. Adhesive Sheet Roll The adhesive sheet roll of the present disclosure (hereinafter also referred to as the present adhesive sheet roll) is a roll sheet in which a long adhesive sheet (hereinafter also referred to as the present adhesive sheet) is wound around a core. The pressure-sensitive adhesive sheet is a substrate-less double-sided pressure-sensitive adhesive laminate in which a light release sheet/adhesive layer/heavy release sheet are laminated in this order. This adhesive sheet roll is suitable for use in flexible displays. However, it does not exclude the use for purposes other than those mentioned above.

This adhesive sheet roll unwinds the adhesive sheet, and if necessary, cuts and punches it. After peeling off the light release sheet, the exposed adhesive layer is attached to the adherend, then the heavy release sheet is peeled off, and the exposed adhesive layer is attached to another adherend. Through such steps, the adherends are bonded together.

The present adhesive sheet roll has an adhesive sheet that satisfies the following (i) to (v).
(i) The thickness of the adhesive layer is 5 to 150 μm.
(ii) In the adhesive sheet unwound from the present adhesive sheet roll, the peel strength when the light release sheet is peeled from the adhesive layer at a peel angle of 180 ° and a peel speed of 300 mm / min in an environment of 23 ° C. and 50% relative humidity. Pl is 0.02 to 0.30N/25mm.
(iii) After peeling off the light release sheet from the adhesive layer, a 50 μm PET film is attached to the exposed adhesive layer, and the heavy release sheet is further removed from the adhesive layer at 23 ° C. and a relative humidity of 50%. The peel force Ph when peeled at 180° at a peel rate of 300 mm/min is 0.10 to 0.80 N/25 mm.
(iv) The ratio of the peel force Ph to the peel force Pl, Ph/Pl, is 2-6.
(v) The thickness Tl of the light release sheet is 25 to 100 μm, the thickness Th of the heavy release sheet is 50 to 188 μm, Tl<Th, and the light release sheet is provided on the outer side of the roll.

The release force Pl of the light release sheet and the release force Ph of the heavy release sheet can be adjusted by releasing treatment of the surface of each release sheet attached to the adhesive layer. For example, the release force can be adjusted by the type of sheet and the type of release agent applied to the substrate surface. Also, the release force can be adjusted by the amount of the release agent applied. Furthermore, it may be adjusted by the surface roughness of the release layer. Moreover, you may adjust with the adhesive composition which forms an adhesion layer. If you want to reduce the peel force value, it is effective to make the surface rough and increase the amount of release agent applied, and if you want to increase the peel force value, adjust the opposite. do it.
The release force Pl of the light release sheet and the release force Ph of the heavy release sheet in the present disclosure were measured by the method described in Examples below. In addition, as shown in the examples described later, the measured value of the release force of the configuration of light release sheet / adhesive layer / PET film 50 μm (G2L, manufactured by Toyobo) and the light release sheet / adhesive layer / heavy release sheet (50 μm The measured values of the light release sheet measured with the above configuration have substantially the same release force.

When the adhesive sheet roll is wound up, tension is applied to the adhesive layer. This may cause micro-unevenness and deformation in the adhesive layer. In addition, foreign substances such as dust and dirt adhering to the adhesive sheet may cause deformation of the adhesive layer through the heavy release sheet or the light release sheet. Furthermore, tunneling phenomena such as floating (bubbles) and partial peeling may occur between the adhesive layer and the release sheet during production, storage, transportation, and the like of the adhesive sheet roll.

Deformation of the adhesive layer, dents, or tunneling phenomenon can be confirmed, for example, by irradiating the adhesive sheet with light and projecting it on a screen. In a display in which a functional layer such as a polarizing plate or an antistatic film is adhered with an adhesive layer, such dents and the like affect visibility and hinder high definition.

As a result of extensive studies by the present inventors, it was found that the adhesive sheet satisfying the above (i) to (v) can maintain the lamination balance of the light release sheet/adhesive layer/heavy release sheet even in the case of a roll body. It was found that the separation of the adhesive layer and the release sheet and partial peeling can be effectively suppressed, and deformation of the adhesive layer and fine unevenness can be suppressed. Further, it was found that air bubbles can be effectively suppressed even if the bending is repeated. According to this pressure-sensitive adhesive sheet, a high-quality pressure-sensitive adhesive sheet roll can be obtained even when used for flexible displays.

The thickness of the adhesive layer Ta is 5 to 150 μm, the peel force Pl is 0.02 to 0.30 N/25 mm, the peel force Ph is 0.10 to 0.80 N/25 mm, and Ph/Pl is 2 to 6. Further, the thickness Tl of the light release sheet is 25 to 100 μm, and the thickness Th of the heavy release sheet is 50 to 188 μm. can be suppressed. Moreover, by setting the adhesive layer to the specific range described above, it is possible to maintain good light transmittance and flexibility while exhibiting adhesive strength.

The thickness Tl of the light release sheet is in the range of 25 to 100 μm, the thickness Th of the heavy release sheet is in the range of 50 to 188 μm, and the relationship of Tl<Th is satisfied. By imparting cushioning properties to the heavy release sheet, it is possible to suppress the occurrence of dents due to foreign matter or shaking during transportation. In addition, by providing the light release sheet, which is thinner than the heavy release sheet, on the outer side of the roll, it is possible to effectively prevent the light release sheet and the adhesive layer from floating, and at the same time, improve the followability to the adhesive layer, thereby improving the adhesive layer. It is possible to effectively improve the conformability of the adhesive layer to minute projections originating from surface irregularities or foreign matter on the outside of the present adhesive sheet. Also, by combining a heavy release sheet and a light release sheet, deformation of the adhesive layer can be suppressed.

Furthermore, by setting the peeling force Pl to 0.02 to 0.30 N/25 mm, it is possible to effectively suppress tunneling phenomena such as lifting of the light release sheet and the adhesive layer and partial peeling. In addition, in the relationship between the peel force Ph and the peel force Pl, by setting Ph to 0.10 to 0.80 N / 25 mm in the range where Ph / Pl satisfies the range of 2 to 6, the adhesive layer and the heavy release sheet The phenomenon of nakiwakare can be effectively suppressed. When a member such as a foam layer, which will be described later, is included, this outer diameter is the outer diameter when the foam layer and the like are included.

FIG. 1 shows an example of a schematic diagram of the pressure-sensitive adhesive sheet roll. The adhesive sheet roll 10 has a long adhesive sheet 3 wound around a core 1 . The winding core 1 can be cylindrical or columnar. The outer diameter (diameter) of the winding core 1 is, for example, about 100 to 1000 mm. The width of the adhesive sheet roll is, for example, about 100 to 3000 mm, and the winding length of the adhesive sheet is, for example, about 10 to 3000 m.

FIG. 2 is a sectional view taken along line II-II of FIG. The adhesive sheet 3 unwound from the adhesive sheet roll 10 has an adhesive layer 7 sandwiched between a light release sheet 8 and a heavy release sheet 6, as shown in FIG. The pressure-sensitive adhesive sheet 3 is a substrate-less laminate, and the release surface of the light release sheet 8 is arranged on the pressure-sensitive adhesive layer 7 side, and the release surface of the heavy release sheet 6 is arranged on the pressure-sensitive adhesive layer 7 side. As shown in FIG. 2, it is preferable that the light release sheet 8 and the heavy release sheet 6 have adhesive layer non-formed regions at both ends in the width direction. A spacer may be arranged between the release sheets in the adhesive layer non-formation region. The spacers can be arranged, for example, in any form such as a line shape or a dot shape along the longitudinal direction of the end portion. By providing the spacer, it is possible to maintain the facing distance and to suppress the protrusion of the adhesive layer. The non-facing area Wa can be, for example, over 20 mm and up to 30 mm.

The core 1 preferably has a foam layer 2 on its outer peripheral surface. The foam layer 2 preferably has a 25% compressive load of 10 to 1000 kPa as measured according to JIS K 6254. By setting it as the said range, the yield of this adhesive sheet roll can be improved and productivity can be improved. Furthermore, deformation of the adhesive layer can be more effectively suppressed. A more preferred range is 30 to 300 kPa, and a further preferred range is 50 to 200 kPa.

The productivity of the double-sided pressure-sensitive adhesive sheet can be improved by aging it in a roll state. On the other hand, there is a problem that the thickness variation of the PSA sheet increases when the PSA sheet is aged in a roll state. One of the reasons for this is that the release sheet is thermally shrunk in the aging process, resulting in irregularities.
As a result of extensive studies by the present inventors, it was found that the occurrence of dents can be remarkably suppressed by setting the standard deviation σ of the thickness Tt of the adhesive sheet to 10% or less of the layer thickness of the adhesive sheet. When the standard deviation σ of the thickness Tt of the present adhesive sheet is 10% or less of the layer thickness of the adhesive sheet, the adhesion area between the adhesive layer and the release sheet increases because the thickness variation of the adhesive layer is small. It is believed that the adhesive layer closely adheres to the unevenness caused by the heat shrinkage of the release sheet in the aging process and prevents the adhesive sheet from being dented. On the other hand, if it is more than 10%, the adhesion between the adhesive layer and the release sheet is reduced, so that when the adhesive layer follows the unevenness of the release sheet, minute peeling occurs, which is thought to lead to the generation of dents. The standard deviation σ is more preferably 8% or less, even more preferably 5% or less.

As a method for reducing the standard deviation σ of the thickness Tt of the adhesive sheet to 10% or less, a light release sheet is wound on an adhesive sheet roll that combines the thickness and release force of each of the light release sheet and the heavy release sheet specified in this adhesive sheet. A method to make it outside is mentioned. Further, in the present pressure-sensitive adhesive sheet, there is a method of adjusting the thickness of the pressure-sensitive adhesive layer to be specified, and a method of adjusting the thickness of each of the light release sheet and the heavy release sheet specified in the pressure-sensitive adhesive sheet.

2. Adhesive Layer The adhesive layer is a double-sided adhesive layer with a thickness of 5 to 150 μm, and serves to bond adherends together. The adhesive layer is sandwiched between the light release sheet and the heavy release sheet at the stage of the adhesive sheet roll. A more preferable range for the thickness Ta of the adhesive layer is 8 to 100 μm, and a more preferable range is 25 to 75 μm. Incidentally, the thickness Ta of the adhesive layer can be obtained by the method of Examples described later.

From the viewpoint of enduring repeated bending and exhibiting excellent restoring force when returning to the original state from the bent state, and from the viewpoint of more effectively preventing the deformation of the adhesive layer in the state of the adhesive sheet roll, the adhesive layer The storage elastic modulus at a frequency of 1 Hz at 23° C. is preferably 1×10 ⁴ to 100×10 ⁴ Pa. Moreover, by using the pressure-sensitive adhesive layer within the above range, it is possible to easily design the release force balance between the light release sheet and the heavy release sheet. When the storage elastic modulus is 1×10 ⁴ or more, it has adhesive strength to adherends and facilitates adjustment of the peel strengths (ii) and (iii) above. In addition, the flexibility of the adhesive layer can be made excellent. The storage elastic modulus can be measured, for example, by DHR-2 manufactured by TA Instruments. The storage modulus can be adjusted by adjusting the monomer composition, the molecular weight of the resin, the amount of the curing agent, drying conditions, and the like. By setting it as the said range, flexibility becomes favorable.

The adhesive strength of the adhesive layer is preferably 10 to 40 N/25 mm to the polyimide substrate at 25°C. By setting it within the above range, it becomes easier to adjust the release force between the light release sheet and the heavy release sheet within the above range. Moreover, flexibility can be effectively exhibited. A more preferred range is 15 to 35 N/25 mm, and a still more preferred range is 20 to 30 N/25 mm. The adhesive strength of the adhesive layer can be controlled by the composition of the adhesive resin constituting the adhesive composition described below, the Tg of the adhesive resin, the amount of the curing agent in the adhesive composition, and the like. When an acrylic copolymer is used as the adhesive resin, the adhesion can be enhanced by including a highly polar acrylic monomer derived from a carboxy group-containing monomer such as acrylic acid. Also, the lower the Tg of the adhesive resin, the higher the adhesive force tends to be. Furthermore, there is a tendency that the smaller the amount of the curing agent in the adhesive composition, the higher the adhesive strength.

The adhesive layer 7 is a layer formed from an adhesive composition. The pressure-sensitive adhesive composition is a cross-linking pressure-sensitive adhesive or non-cross-linking pressure-sensitive adhesive, and may be emulsion type, solvent type or non-solvent type.

The adhesive composition contains an adhesive resin as a main component. In addition, a main component here means the component with most content (mass) in a non-volatile matter. Examples of adhesive resins include acrylic copolymers, rubber resins, silicone resins, urethane resins, polyamide resins, polyimide resins, polyester resins, and fluorine resins. These resins may be used alone or in combination of two or more. Acrylic copolymers are preferable from the viewpoint of excellent transparency in addition to adhesiveness.

This pressure-sensitive adhesive composition can contain a curing agent as needed. Examples of curing agents include isocyanate compounds, epoxy compounds, aziridine compounds, carbodiimide compounds, metal chelates, and the like. The curing agent may be a low-molecular-weight compound or a high-molecular-weight compound. Among these, isocyanate compounds are preferable from the viewpoint of achieving both high cohesion and adhesion.

A suitable adhesive layer is obtained by cross-linking an adhesive composition containing a (meth)acrylic copolymer having a gel fraction of 50 to 90% and a storage elastic modulus of 10 MPa or less at −30° C. An adhesive layer is mentioned. Preferred examples of (meth)acrylic copolymers include linear or branched alkyl (meth)acrylic copolymers having 8 to 20 carbon atoms in structural units and/or alkyl groups derived from alicyclic (meth)acrylate monomers. ) A (meth)acrylic copolymer (a) having a constitutional unit derived from an acrylate monomer can be exemplified.
Examples of more suitable (meth)acrylic copolymers (a) include linear alkyl ( A (meth)acrylic copolymer (a) having a structural unit derived from a meth)acrylate monomer and a structural unit derived from a branched alkyl (meth)acrylate monomer having 8 to 20 carbon atoms is exemplified. can.
By including a structural unit derived from an alicyclic (meth) acrylate monomer and / or a structural unit derived from a linear alkyl (meth) acrylate monomer having an alkyl group having 10 to 20 carbon atoms, the adhesive layer It is possible to relieve the stress applied when repeatedly bending the adhesive layer and prevent the adhesive layer from slipping. In addition, by containing a structural unit derived from a branched alkyl (meth)acrylate monomer having 8 to 20 carbon atoms, the cohesive force of the adhesive layer is increased, and whitening of the bent portion can be prevented. Evaluation of air bubbles described in 1 becomes good.

A more preferred range of gel fraction is 55-85%, and a more preferred range is 60-80%. The storage modulus of the adhesive layer at −30° C. is more preferably 8 MPa or less, more preferably 5 MPa or less. By setting the gel fraction within the above range, air bubbles at the bending portion are improved.
The gel fraction of the adhesive layer can be adjusted by adjusting the aging time, aging temperature, and amount of curing agent. By adjusting the ratio of the hydroxyl group-containing monomer in the (meth)acrylic copolymer (a), the gel fraction can be controlled within the above range. The gel fraction tends to increase by increasing the ratio of the hydroxyl group-containing monomer. The lower limit of the −30° C. storage modulus of the adhesive layer is preferably 0.5 MPa from the viewpoint of air bubbles at the bending point. The above storage elastic modulus is obtained by adding structural units derived from linear and/or branched alkyl (meth)acrylate monomers having 8 to 20 carbon atoms in the alkyl group to the (meth)acrylic copolymer (a). can be adjusted by using The larger the number of carbon atoms in the alkyl group of the alkyl (meth)acrylate monomer or the larger the number of branched chain portions, the more the bulky alkyl groups become entangled in the adhesive layer, so the storage elastic modulus tends to decrease.

2-1. Adhesive Resin The weight-average molecular weight (Mw) of the adhesive resin is 500,000 or more, preferably 800,000 to 1,800,000, and more preferably 900,000 to 1,700,000 from the viewpoint of achieving both strength and punching workability. is more preferred, and 1,000,000 to 1,500,000 is even more preferred. In addition, the Tg of the adhesive resin is preferably -30 ° C. or less as a result of suggestive scanning calorimetry (DSC) of the adhesive layer from the viewpoint of improving the flexibility of the adhesive layer. It is preferably -32°C or lower, more preferably -35°C or lower. Although the lower limit of the Tg of the adhesive resin is not particularly limited, it is preferably -50°C or higher from the viewpoint of heat resistance.

A (meth)acrylic copolymer is obtained, for example, by copolymerizing a functional group-containing monomer and a (meth)acrylic acid ester. Preferred examples of (meth)acrylic acid esters include (meth)acrylic acid alkyl esters.

The alkyl group of the (meth)acrylic acid alkyl ester may be a linear, branched or cyclic alkyl group. The alkyl group is preferably an alkyl group having 1 to 20 carbon atoms. From the viewpoint of increasing flexibility, a monomer containing at least a cyclic alkyl group (alicyclic) and/or a linear or branched alkyl (meth)acrylate monomer having 8 to 20 carbon atoms in the alkyl group A (meth)acrylic copolymer (a) obtained by copolymerizing a polymer is preferred. Specific examples of monomers 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, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, (meth)acrylate 2-ethylhexyl acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, (meth) ) dodecyl acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, (meth) acrylate nonadecyl acrylate, eicosyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, 4-n-butylcyclohexyl (meth)acrylate, and isobornyl (meth)acrylate. Among these, from the viewpoint of flexibility and adhesive strength, methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-butyl (meth)acrylate, hexyl (meth)acrylate, and (meth)acrylic acid Dodecyl, cyclohexyl (meth)acrylate and isobornyl (meth)acrylate are preferred, and 2-ethylhexyl acrylate, dodecyl (meth)acrylate, cyclohexyl (meth)acrylate and isobornyl (meth)acrylate are particularly preferred.

The (meth)acrylic acid alkyl ester preferably has a homopolymer Tg of -80 to 110°C. Moreover, it is preferable to use together the (meth)acrylic acid alkyl ester which has a linear alkyl group, and the (meth)acrylic acid alkyl ester which has an alicyclic alkyl group.
The Tg of the homopolymer can be calculated from the Tgn of the polymer obtained by polymerizing the (meth)acrylic acid alkyl ester alone according to the following Fox formula.
Fox formula: 100/Tg=Σ(Wn/Tgn)
Tg: Calculated Tg (K) of the polymer
Wn: Mass fraction (%) of monomer n
Tgn: glass transition temperature (K) of homopolymer of monomer n
The Tg value (Tgn) of the homopolymer of the monomer n can be obtained, for example, from the technical data of monomer manufacturers such as Nippon Shokubai Co., Ltd., Mitsubishi Chemical Co., Ltd., Toagosei Co., Ltd. and Polymer Data Handbook (published by Baifukan, edited by the Society of Polymer Science ( Basic edition), January 1986 first edition), Polymer Handbook 4th edition (J. Brandrup, EH Immergut, EA Grulke, 1999, Wiley-Interscience). For example, the homopolymer Tg of each monomer is methyl methacrylate (105°C), dodecyl acrylate (-10°C), 2-ethylhexyl acrylate (-70°C), butyl acrylate (-54°C), isobornyl acrylate (94°C ), cyclohexyl acrylate (19° C.) and 4-hydroxybutyl acrylate (−40° C.).

Among (meth)acrylic copolymers, the above-mentioned (meth)acrylic copolymer (a) is particularly preferable. Structural units derived from a linear or branched (meth)acrylic acid alkyl ester having 8 to 20 carbon atoms in the alkyl group relative to 100% by mass of the (meth)acrylic copolymer (a) are 10 to It is preferably 100% by mass, more preferably 20 to 90% by mass, even more preferably 30 to 85% by mass.
Further, relative to 100% by mass of the (meth)acrylic copolymer (a), a straight chain having 10 to 20 carbon atoms in the structural unit derived from the alicyclic (meth)acrylate monomer and/or the alkyl group The structural unit derived from the alkyl (meth)acrylate monomer is preferably 10 to 90% by mass, more preferably 10 to 75% by mass, even more preferably 15 to 50% by mass.
Further, the (meth)acrylic copolymer (a) is 100% by mass, and the structural unit derived from a branched alkyl (meth)acrylate monomer having 8 to 20 carbon atoms is 10 to 90% by mass. is preferred, 20 to 85 mass % is more preferred, and 40 to 85 mass % is even more preferred.

The (meth)acrylic copolymer (a) can contain functional group monomers. Examples of functional group-containing monomers include carboxy group-containing monomers, hydroxyl group-containing monomers, epoxy group-containing monomers, and amino group-containing monomers. Containing a functional group-containing monomer improves the cohesive strength of the adhesive, resulting in a tough adhesive layer.

Examples of carboxy group-containing monomers include (meth)acrylic acid, β-carboxyethyl acrylate, p-carboxybenzyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, citraconic acid and isocrotonic acid. can. Among these, (meth)acrylic acid is particularly preferred from the viewpoint of cohesive strength and adhesive strength.

Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and (meth)acryl. 4-hydroxybutyl acid, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4- Hydroxymethylcyclohexyl)methyl (meth)acrylate can be exemplified. Among these, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate are more preferable from the viewpoint of cohesive strength and adhesive strength.

Examples of epoxy group-containing monomers include glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, and 6-methyl-3,4-epoxycyclohexyl (meth)acrylate. Methyl can be exemplified.

Examples of amino group-containing monomers include (meth) acrylics such as monomethylaminoethyl (meth)acrylate, monoethylaminoethyl (meth)acrylate, monomethylaminopropyl (meth)acrylate, and monoethylaminopropyl (meth)acrylate. Acid monoalkylaminoesters can be exemplified.

The total amount of structural units derived from functional group-containing monomers is preferably 1 to 20% by mass with respect to 100% by mass of the (meth)acrylic copolymer (a). By setting the content within the above range, cohesive force can be adjusted by reaction with the curing agent, and flexibility and restoring force can be enhanced.
The (meth)acrylic copolymer (a) preferably contains 1 to 10% by mass of structural units derived from the carboxy group-containing monomer relative to 100% by mass. By being within the above range, both the cohesive strength and relaxation properties of the adhesive layer can be achieved. Further, the (meth)acrylic copolymer (a) preferably contains 1 to 10% by mass of structural units derived from a hydroxyl group-containing monomer with respect to 100% by mass. By being within the above range, both adhesion and relaxation properties of the adhesive layer can be achieved.

The (meth)acrylic copolymer (a) may contain structural units derived from other monomers copolymerizable with the above monomers. Examples thereof include monomers having an alkyleneoxy group and other vinyl monomers. Examples include methoxyethyl acrylate, methoxydiethylene glycol acrylate, vinyl acetate, vinyl crotonate, styrene, and acrylonitrile. The structural unit derived from the other monomer is preferably 0.1 to 20% by mass in 100% by mass of the (meth)acrylic copolymer (a).

The (meth)acrylic copolymer (a) is obtained by polymerizing a monomer mixture. A polymerization initiator can be used at the time of polymerization, if necessary. The content of the polymerization initiator is, for example, 0.01 to 10 parts by mass with respect to 100 parts by mass of the monomer mixture. The polymerization method is not limited. Examples thereof include solution polymerization, bulk polymerization, emulsion polymerization, and suspension polymerization. Examples of solvents used in solution polymerization include acetone, methyl acetate, ethyl acetate, toluene, xylene, anisole, methyl ethyl ketone, and cyclohexanone. The polymerization temperature is, for example, 60 to 120° C., and the polymerization time is about 5 to 12 hours.

The polymerization initiator is preferably a radical polymerization initiator. Peroxides and azo compounds are suitable as radical polymerization initiators. 2,2'-azobisbutyronitrile such as 2,2'-azobisisobutyronitrile (abbreviation: AIBN), 2,2'-azobis(2-methylbutyronitrile); 2,2′-azobisvaleronitrile such as ,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis(2,4-dimethylvaleronitrile); - 2,2'-azobispropionitrile such as azobis(2-hydroxymethylpropionitrile); 1,1'-azobis-1-alkanes such as 1,1'-azobis(cyclohexane-1-carbonitrile) Nitriles may be mentioned. Peroxides are, for example, di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5- Dialkyl peroxides such as di(t-butylperoxy)hexyne-3; t-butylperoxybenzoate, t-butylperoxyacetate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane Peroxy esters; ketone peroxides such as cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, and methylcyclohexanone peroxide; 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, n-butyl-4,4-bis(t-butylperoxy ) peroxyketals such as barate; hydroperoxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylcyclohexane-2,5-dihydroperoxide; benzoyl peroxide, decanoyl peroxide, diacyl peroxides such as lauroyl peroxide and 2,4-dichlorobenzoyl peroxide; and peroxydicarbonates such as bis(t-butylcyclohexyl)peroxydicarbonate.

2-2. Curing Agent The pressure-sensitive adhesive composition may contain a curing agent, if necessary. By having a crosslinked structure, it is possible to provide an adhesive layer having excellent adhesive strength and cohesive strength. Suitable examples of curing agents can be designed according to the functional groups of the adhesive resin. Suitable curing agents include isocyanate compounds, epoxy compounds, aziridine compounds, carbodiimide compounds, metal chelates, and the like. When the functional group is a hydroxy group or a carboxy group, isocyanate compounds and epoxy compounds are preferred, and among these, isocyanate compounds are preferred from the viewpoint of achieving both high cohesion and adhesion. A preferred example is a pressure-sensitive adhesive composition comprising a (meth)acrylic copolymer (a) as a pressure-sensitive adhesive resin and an isocyanate compound as a curing agent.

An isocyanate compound is an isocyanate having two or more isocyanate groups. Isocyanate compounds are preferably isocyanate monomers such as aromatic polyisocyanates, aliphatic polyisocyanates, araliphatic polyisocyanates and alicyclic polyisocyanates, and burettes, nurates and adducts thereof.

Aromatic polyisocyanates are, for example, 1,3-phenylene diisocyanate, 4,4'-diphenyldiisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6- tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanatotoluene, 1,3,5-triisocyanatobenzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4',4 ''-triphenylmethane triisocyanate.

Aliphatic polyisocyanates include, for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (also known as HMDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate.

Aroaliphatic polyisocyanates are, for example, ω,ω′-diisocyanate-1,3-dimethylbenzene, ω,ω′-diisocyanate-1,4-dimethylbenzene, ω,ω′-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate and 1,3-tetramethylxylylene diisocyanate.

Alicyclic polyisocyanates include, for example, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (also known as IPDI, isophorone diisocyanate), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4 -cyclohexanediisocyanate, methyl-2,4-cyclohexanediisocyanate, methyl-2,6-cyclohexanediisocyanate, 4,4'-methylenebis(cyclohexylisocyanate), 1,4-bis(isocyanatomethyl)cyclohexane.

The burette body is a self-condensed product having a burette bond formed by self-condensation of an isocyanate monomer. The burette body includes, for example, a burette body of hexamethylene diisocyanate.

The nurate compound is a trimer of isocyanate monomers. Examples thereof include a trimer of hexamethylene diisocyanate, a trimer of isophorone diisocyanate, a trimer of tolylene diisocyanate, and the like.

The adduct is a bifunctional or higher isocyanate compound obtained by reacting an isocyanate monomer and a bifunctional or higher low-molecular-weight active hydrogen-containing compound. Adducts include, for example, a compound obtained by reacting trimethylolpropane and hexamethylene diisocyanate, a compound obtained by reacting trimethylolpropane and tolylene diisocyanate, a compound obtained by reacting trimethylolpropane and xylylene diisocyanate, trimethylol A compound obtained by reacting propane with isophorone diisocyanate and a compound obtained by reacting 1,6-hexanediol with hexamethylene diisocyanate can be mentioned.

The isocyanate compound is preferably a trifunctional isocyanate compound from the viewpoint of forming a sufficient crosslinked structure. The isocyanate compound is more preferably an adduct or a nurate which is a reaction product of an isocyanate monomer and a trifunctional low-molecular-weight active hydrogen-containing compound. Isocyanate compounds include trimethylolpropane adduct of hexamethylene diisocyanate, nurate of hexamethylene diisocyanate, trimethylolpropane adduct of tolylene diisocyanate, nurate of tolylene diisocyanate, trimethylolpropane adduct of isophorone diisocyanate, and isophorone diisocyanate. A nurate compound is preferred, and a trimethylolpropane adduct of hexamethylene diisocyanate, a trimethylolpropane adduct of tolylene diisocyanate, and a trimethylolpropane adduct of isophorone diisocyanate are more preferred.

Epoxy compounds include, for example, glycerol diglycidyl ether, 1,6-hexanediol diglycidyl ether, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N'- diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidylaminophenylmethane.

Aziridine compounds include, for example, N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxite), tris-2,4,6-(1-aziridinyl)-1,3,5-triazine, 4, 4'-bis(ethyleneiminocarbonylamino)diphenylmethane is mentioned.

The carbodiimide compound is preferably a high-molecular-weight polycarbodiimide produced by a decarboxylation condensation reaction of a diisocyanate compound in the presence of a carbodiimidation catalyst. Carbodilite series manufactured by Nisshinbo Co., Ltd. is preferable as the commercial product of the high-molecular-weight polycarbodiimide. Among them, Carbodilite V-03, 07 and 09 are preferable because of their excellent compatibility with organic solvents.

Metal chelates are preferably coordination compounds of polyvalent metals such as, for example, aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium, with acetylacetone or ethyl acetoacetate. Examples of metal chelates include aluminum ethylacetoacetate/diisopropylate, aluminum trisacetylacetonate, aluminum bisethylacetoacetate/monoacetylacetonate, and aluminum alkylacetoacetate/diisopropylate.

The curing agent is preferably contained in an amount of 0.001 to 1 part by mass, more preferably 0.01 to 0.1 part by mass, based on 100 parts by mass of the adhesive resin. When the content is 0.01 part by mass or more, the cohesive force is further improved, and when the content is 1 part by mass or less, cohesive force and flexibility are easily compatible, which is preferable.

2-3. Other Additives This adhesive composition may further contain solvents, tackifiers, silane coupling agents, fillers, tackifier resins, colorants, antioxidants, antistatic agents, ultraviolet absorbers, etc., as necessary. may contain.

Examples of solvents include esters such as ethyl acetate, propyl acetate and butyl acetate, and ketones such as acetone, methyl ethyl ketone and cyclohexanone. In addition, aromatic hydrocarbons such as toluene, xylene, benzene, solvent naphtha, cyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, ethylcyclohexane, diethylcyclohexane, decahydronaphthalene, bicycloheptane, tricyclodecane, hexahydro Aliphatic hydrocarbons such as indenecyclohexane, cyclooctane, α-pinene, terpinolene, and limonene. Solvents may be used alone or in combination.

Silane coupling agents include, for example, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropyltripropoxysilane, 3-(meth)acryloxysilane alkoxysilane compounds having a (meth)acryloxy group, such as roxypropyltributoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane;
alkoxysilane compounds having a vinyl group such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane;
3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltripropoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)- 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl) -Alkoxysilane compounds having an amino group such as 3-aminopropylmethyldiethoxysilane and N-phenyl-3-aminopropyltrimethoxysilane;
Alkoxysilane compounds having a mercapto group such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltripropoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane;
3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltripropoxysilane, 3-glycidoxypropyltributoxysilane, 3-glycidoxypropylmethyldimethoxysilane, Alkoxysilane compounds having an epoxy group such as 3-glycidoxypropylmethyldiethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane;
Tetraalkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane;
3-chloropropyltrimethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-decyltrimethoxysilane, n-decyltriethoxysilane, styryltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyl Examples include triethoxysilane, hexamethyldisilazane, and silicone resins having alkoxysilyl groups in the molecule.

The silane coupling agent is preferably used in an amount of 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, with respect to 100 parts by mass of the adhesive resin.

Optical properties and mechanical properties can be adjusted by adding a filler. Examples of fillers include inorganic white pigments such as silica, calcium carbonate, aluminum hydroxide, magnesium hydroxide, clay, talc, and titanium dioxide.

Examples of tackifying resins include rosin-based resins, polymerized rosin-based resins, rosin ester-based resins, polymerized rosin ester-based resins, terpene-based resins, terpene phenol-based resins, coumarone-based resins, coumarone-indene-based resins, xylene-based resins, Examples include phenolic resins and petroleum resins. When an acrylic copolymer is used as the adhesive resin, rosin-based resins, polymerized rosin-based resins, rosin ester-based resins, and polymerized rosin ester-based resins are preferred from the viewpoint of good compatibility and improved adhesive performance. Resins and polymerized rosin ester-based resins are more preferred. The tackifying resin is preferably used in an amount of 0.01 to 10 parts by mass, more preferably 0.5 to 7 parts by mass, per 100 parts by mass of the (meth)acrylic copolymer (a). A high adhesive strength can be obtained by using 0.01 to 10 parts by mass of the tackifying resin.

3. Light release sheet and heavy release sheet The light release sheet and heavy release sheet serve to protect the adhesive layer. Light release sheets and heavy release sheets that satisfy the above (ii) to (v) are used. A more preferred range for Tl is 25 to 75 μm, and an even more preferred range is 25 to 50 μm. A more preferable range for Th is 50 to 150 μm, and a more preferable range is 75 to 125 μm. From the viewpoint of improving productivity, the light release sheet and the heavy release sheet may be made of the same material with different thicknesses.

The film thickness difference (Th-Tl) is preferably 15 μm or more, more preferably 25 μm or more. The upper limit is preferably 140 μm or less, more preferably 95 μm or less. By setting the film thickness difference to 15 μm or more, the stress applied to the adhesive when the light release sheet is peeled off is dispersed in the heavy release sheet, and cohesive failure of the adhesive during peeling can be prevented. By setting the film thickness difference to 140 μm or less, the stress applied to the adhesive when the light release sheet is peeled off is distributed to the heavy release sheet, making it easier to peel off the light release sheet smoothly and preventing zipping.

A more preferred range of Ph/Pl is 2.5-5. A more preferable range of Pl is 0.02 to 0.2N/25mm, and a more preferable range is 0.02 to 0.1N/25mm. A more preferred range for Ph is 0.15 to 0.6N/25mm, and a more preferred range is 0.2 to 0.5N/25mm.

Light release sheets and heavy release sheets (hereinafter collectively referred to as "release sheets") are, for example, polyethylene sheets, polypropylene sheets, polybutene sheets, polybutadiene sheets, polymethylpentene sheets, polyvinyl chloride sheets, vinyl chloride copolymers Sheet, polyethylene terephthalate sheet, polyethylene naphthalate sheet, polybutylene terephthalate sheet, polyurethane sheet, ethylene vinyl acetate sheet, ionomer resin sheet, ethylene/(meth)acrylic acid copolymer sheet, ethylene/(meth)acrylate copolymer A united sheet, a polystyrene sheet, a polycarbonate sheet, a polyimide sheet, and a fluororesin sheet can be exemplified. The release sheet may be a single layer or a laminate.

In addition to using a release sheet itself having releasability, a release sheet obtained by coating a release agent on a substrate may be used. Releasability can be imparted by applying a release agent to the joint surface with the adhesive layer. The release sheet may have other functional layers in addition to the substrate/release layer. Examples of release layers having other functional layers include antistatic layer/substrate/release layer and substrate/antistatic layer/release layer.

Specific examples of release agents include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based agents. The above (ii) to (iv) can be adjusted depending on the type of release agent. As another adjustment method for (ii) to (iv), there is a method for adjusting the thickness of the light release sheet and the heavy release sheet as described later.

From the standpoint of ease of designing the peel strength, a silicone-based release agent is suitable. A suitable example is a release agent containing a linear silicone as a main component and further containing a branched silicone.

The silicone release agent contains silicone having a siloxane bond in its main chain. As the silicone, for example, a type having three organic substituents bonded to silicon and one oxygen atom (M unit), and a type having two organic substituents bonded to silicon and two oxygen atoms (D unit ), a type having one organic substituent bonded to silicon and three oxygen atoms (T unit), and a type having no organic substituent bonded to silicon and having four oxygen atoms (Q unit). It is possible to obtain various silicones with different peeling performances, and the magnitude of the peeling strength can be controlled by the ratio of these. In most cases, it is possible to make adjustments to make peeling easier with straight-chain silicones composed of M and D units, and to make peeling harder with branched silicones containing T and Q units in the structure of straight-chain silicones. .

As the linear silicone, a composition containing D units as a main component and appropriately containing M units for molecular weight adjustment is preferred. The organic substituent represents a hydrogen atom, a hydroxyl group, or an alkyl group, preferably an alkyl group, specifically a methyl group or a phenyl group, from the viewpoint of being easily soluble in an organic solvent.

Since linear silicone imparts various resistances, it can have a crosslinked structure. The straight-chain silicone preferably has two or more vinyl groups at its terminals and/or side chains as cross-linking points. The curing agent includes hydrogen-modified silicone and the like, and it is necessary to have two or more SiH groups in one molecule. It is preferable to include 0.1 to 20 parts by mass of hydrogen-modified silicone with respect to 100 parts by mass of linear silicone.

The branched silicone preferably has T units and/or Q units, and preferably contains 70% by mass or more of T units and/or Q units in 100% by mass of the branched silicone. Branched silicones may have M units, D units in addition to T units and/or Q units.

The release layer is formed from a release agent. The release agent according to the present invention contains straight-chain silicone and branched silicone in a ratio of straight-chain silicone:branched silicone=100:0 to 99:1 (mass ratio). By containing the branched silicone in an amount of 1% by mass or less based on the total mass of the release agent (straight-chain silicone, hydrogen-modified silicone and branched silicone), dust resistance and anti-displacement properties are improved. The proportion of branched silicone is more preferably 0.5% by mass or less, and even more preferably 0.2% by mass or less.

The total content of linear silicone, hydrogen-modified silicone and branched silicone is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, based on 100% by mass of the total mass of the release agent. Preferably, it is more preferably 90 to 100% by mass.

Methods for synthesizing the silicone release agent include addition reaction, peroxide condensation reaction, and ultraviolet cross-linking reaction, and the addition reaction is preferred. The addition reaction is the cross-linking of the vinyl groups contained in the linear silicone and the SiH groups contained in the hydrogen-modified silicone.

When the release agent is synthesized by an addition reaction, it contains a catalyst. The catalyst is not particularly limited, but platinum-based catalysts are preferable, and chloroplatinic acid such as chloroplatinic acid and chloroplatinic acid, alcohol compounds of chloroplatinic acid, aldehyde compounds, or chloroplatinic acid Complexes with various olefins and the like are more preferable. The amount of the catalyst added is preferably 0.01 to 10% by mass, more preferably 0.2 to 2% by mass, based on 100% by mass of the total mass of the release agent.

The release agent may contain any appropriate other component as long as the effects of the present disclosure are not impaired. Examples thereof include reaction inhibitors, inorganic fillers, organic fillers, colorants (dyes, pigments, etc.), plasticizers, ultraviolet absorbers, antioxidants, and the like.

The release layer is preferably formed by coating a release agent composition on a release substrate. The release agent can contain a solvent when applied. The type of solvent is not limited, but hydrocarbon solvents such as normal hexane, cyclohexane, and normal heptane; aromatic solvents such as toluene and xylene; ester solvents such as ethyl acetate and methyl acetate; ketone solvents such as acetone and methyl ethyl ketone. Solvent; Organic solvents such as alcohol solvents such as methanol, ethanol, and butanol can be exemplified.

The release agent can be applied onto the base material using a micro gravure coater, a gravure coater, or the like. The release agent can be applied in a solid mass of, for example, 0.1 to 2.0 g/m ² , preferably 0.5 to 1.2 g/m ² , and cured to form a release layer. can.

Curing of the coating film of the release agent is preferably thermosetting. The addition reaction can be efficiently accelerated by heat curing. Although the curing temperature is not limited, 80 to 130°C is suitable. By setting the temperature to 80° C. or higher, the curing reaction can be efficiently performed, and the productivity can be improved. Further, by setting the temperature to 130° C. or less, it is possible to reduce the deterioration of the base material (wrinkling due to heat, etc.) and increase the options for the base material. Although the thickness of the release layer is not limited, it is, for example, about 0.1 to 2 μm.

4. Production of Adhesive Sheet Roll The production method of the adhesive sheet roll of the present disclosure can be produced by a known method. For example, a step of applying a pressure-sensitive adhesive composition on a heavy release sheet to form a coating film and curing to form an adhesive layer, and attaching a light release sheet to one exposed surface of the pressure-sensitive adhesive layer to form an adhesive layer. get a sheet. And it is obtained by winding up the obtained adhesive sheet in roll shape.

Coating can be performed by, for example, a micro gravure coater, gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, rod blade coater, knife coater, spray coater, die coater, or curtain coater. When the adhesive composition contains a solvent, the solvent is removed by a drying step after coating. Curing is performed, for example, by aging. In the case of a photocurable pressure-sensitive adhesive composition, it is cured by irradiation with UV or the like.

A pressure-sensitive adhesive sheet roll can be obtained by winding the pressure-sensitive adhesive sheet around the winding core after the pressure-sensitive adhesive sheet is manufactured or while the pressure-sensitive adhesive sheet is being manufactured. The winding length can be designed according to the application. The length of the pressure-sensitive adhesive sheet can be appropriately designed, but from the viewpoint of improving productivity, it is preferably 50 m or longer, more preferably 100 m or longer. The winding length is preferably 2500 m or less from the viewpoint of production yield.

In addition, the release surface of the light release sheet and the heavy release sheet is coated with an adhesive layer so that the thickness after drying becomes a predetermined thickness, and after forming two adhesive layers, each adhesive layer is attached. You may manufacture by the method to carry out.

5. Flexible Display A flexible display includes an optical element such as a liquid crystal element or an organic EL element, and an adhesive layer formed from an adhesive sheet unwound from the present adhesive sheet roll. The flexible display is a bendable display, and preferably a display capable of repeated bending including folding. For example, an organic electroluminescence (organic EL) display, an electrophoretic display (electronic paper), a liquid crystal display using a plastic substrate (film) as a substrate, and a foldable display can be exemplified.

The adhesive layer formed from this adhesive sheet is suitable for bonding flexible members. For example, liquid crystal polymer sheet, luminescent polymer sheet, sheet liquid crystal module, organic EL module (organic EL sheet), electronic paper module, transparent conductive sheet, metal mesh sheet, sheet sensor, cover sheet, barrier film, polarizing film, polarized light It is suitable for adhering members of any combination of a layer, a retardation film, a viewing angle compensation film, a brightness enhancement film, a contrast enhancement film, a diffusion film, a transflective film, and an electrode film.

The present disclosure will be described in more detail below based on examples. However, the present disclosure is not limited by these. Unless otherwise specified, "part" in the examples indicates "mass part" and "%" indicates "% by mass". A blank column in the table indicates that it was not blended.

(a) Measurement method Numerical values obtained in the present examples are values obtained by the following methods. Each measurement point (film thickness, peel strength, etc.) of the adhesive sheet roll was performed at a position of 50% of the winding length of the adhesive sheet roll.

a-1. Glass Transition Temperature The glass transition temperature (Tg) of the (meth)acrylic copolymer (a) and the adhesive layer was measured by a robot DSC (differential scanning calorimeter, "RDC220" manufactured by Seiko Instruments Inc.). About 2 mg of sample was placed in an aluminum pan, weighed and set in a differential scanning calorimeter, and the same type of aluminum pan without sample was used as a reference. After holding at a temperature of 100° C. for 5 minutes, it was rapidly cooled to −120° C. using liquid nitrogen, and then heated at a temperature increase rate of 5° C./min. Tg (° C.) was determined from the obtained DSC chart. .

a-2. Mw of resin
Using a GPC "LC-GPC system" manufactured by Shimadzu Corporation, Mw was obtained by converting polystyrene having a known molecular weight as a standard substance.
Apparatus name: LC-GPC system "Prominence" manufactured by Shimadzu Corporation
Column: 4 GMHXL manufactured by Tosoh Corporation and 1 HXL-H manufactured by Tosoh Corporation were connected.
Mobile phase solvent: Tetrahydrofuran Flow rate: 1.0 mL/min Column temperature: 40°C

a-3. Film thickness 10 points were determined at equal intervals from one end of the adhesive sheet roll to the other in the width direction, the thickness of the ten points was measured, and the average value was taken as the thickness Tt of the adhesive sheet. The term "end portion" as used herein refers to the end portion where the light release sheet/adhesive layer/heavy release sheet are laminated. Next, the light release sheet was peeled off from the adhesive sheet roll, and the thickness of the peeled light release sheet at 10 positions corresponding to the same positions as above was measured. Let the average value be the thickness Tl of the light release sheet. After that, the heavy release sheet was further peeled off from the adhesive layer, and the thickness of the peeled heavy release sheet at 10 positions corresponding to the same positions as described above was measured. The average value is defined as the thickness Th of the heavy release sheet. The thickness Ta of the adhesive layer was obtained from Tt-Tl-Th.

a-4. Standard Deviation of Thickness of Adhesive Sheet From the above "a-3", the standard deviation σ of the in-plane thickness of the thickness Tt of the adhesive sheet was obtained. That is, the standard deviation σ was determined from the film thickness at 10 locations equally spaced from one end to the other end in the width direction of the adhesive sheet roll.

a-5. Storage modulus G' of the adhesive layer (storage modulus at -30°C)
Two sets of adhesive sheets were prepared by peeling off the light release sheet of the adhesive sheet roll, and the adhesive layers were laminated together by a laminator to prepare a laminate of heavy release sheet/adhesive layer/heavy release sheet. The heavy release sheet on one side of the laminate was peeled off, and the pressure-sensitive adhesive sheet from which the light release sheet was peeled off was repeatedly adhered to form a laminate having an adhesive layer with a thickness of 1 mm. Using a rheometer (DHR-2, manufactured by TA Instruments Co., Ltd.), a strain of 0.1%, a frequency of 1 Hz, and a heating rate of 10°C from -70°C to 200°C were applied to this laminate. /min to determine the storage modulus G' at -30°C.

a-6. Peeling force Pl of the light release sheet to the adhesive layer
After the pressure-sensitive adhesive sheet was produced by the method described below, after 24 hours in an environment of 23 ° C. and a relative humidity of 50%, the light release sheet was peeled off at a peel angle of 180 ° and a peel speed of 300 mm / min under the environment. The peel force Pl of the light release sheet to the layer was determined.

a-7. Peel force Ph of the heavy release sheet to the adhesive layer
For the sample for which the peel force Pl of the light release sheet was determined in a-6 above, a 50 μm PET film (G2L, manufactured by Toyobo Co., Ltd.) was pasted on the exposed surface of the adhesive layer, and then the peel angle was 180 ° and the peel speed was 300 mm / By minutes, the heavy release sheet was peeled off, and the peel strength Ph of the heavy release sheet to the adhesive layer was determined.

a-8. Gel Fraction of Adhesive Layer The adhesive sheet was cut into a size of 30 mm×100 mm, and the adhesive layer exposed by peeling off the light release sheet was attached to a weighed 300-mesh stainless steel wire mesh (mass W0). Then, the heavy release sheet was peeled off to obtain a sample of stainless steel wire mesh/adhesive layer. The weight obtained by weighing the sample was defined as W1, and the sample was allowed to stand still in ethyl acetate for 24 hours, then the sample was taken out, dried at 100° C. for 1 hour, and the weight obtained by weighing was defined as W2, which was calculated using the following formula.
Gel fraction (%) = {(W2-W0)/(W1-W0)} x 100

(b) Production example of adhesive resin b-1. Adhesive resin R1
100 parts of ethyl acetate and 2-ethylhexyl acrylate (2EHA) 83 were placed in a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube (hereinafter simply referred to as "reaction vessel"). part, isobornyl acrylate (IBXA) 15 parts, 4-hydroxybutyl (meth) acrylate (4HAB) 2 parts, 2,2'-azobisisobutyronitrile as an initiator (hereinafter simply referred to as "AIBN" .) was charged, and the atmosphere in the reaction vessel was replaced with nitrogen gas. After that, the reaction solution was heated to 65° C. while stirring under a nitrogen atmosphere, and the reaction solution was allowed to react at 65° C. for 4 hours. After completion of the reaction, it was cooled and diluted with ethyl acetate to obtain an adhesive resin ((meth)acrylic copolymer (a)) R1 solution (Mw: 1,200,000, Tg: -48°C) having a non-volatile content of 30%. .

b-2. Adhesive resin R2, R3
Adhesive resins ((meth)acrylic copolymer (a)) R2 and R3 were obtained in the same manner as for adhesive resin R1, except that the monomers and blending amounts were changed as shown in Table 1. Table 1 shows Mw and Tg.
Symbols in Table 1 are as follows.
MA: methyl acrylate (straight-chain alkyl group with 1 carbon atom)
BA: butyl acrylate (straight-chain alkyl group with 4 carbon atoms)
2EHA: 2-ethylhexyl acrylate (branched alkyl group with 8 carbon atoms)
DOA: dodecyl acrylate (straight-chain alkyl group with 12 carbon atoms)
IBXA: isobornyl acrylate (alicyclic alkyl group)
CHA: cyclohexyl acrylate (alicyclic alkyl group)
4HBA: 4-hydroxybutyl (meth)acrylate AA: acrylic acid

(c) Preparation of adhesive composition c-1. Production of pressure-sensitive adhesive composition C1 Per 100 parts of the non-volatile content of the pressure-sensitive adhesive resin R1, 0.5 parts of aromatic isocyanate D-110N as a curing agent and ethyl acetate are blended and stirred so that the non-volatile content is 20%. to obtain a pressure-sensitive adhesive composition C1 (see Table 2).

c-2. Production of PSA Compositions C2 and C3 PSA compositions C2 and C3 were obtained in the same manner as for PSA composition C1 except that PSA resin R1 was changed to R2 and R3 (see Table 2).

(d) Production of release sheet d-1. Release sheet RS1
100 parts of Silicone A, 1 part of platinum-based catalyst, and 200 parts of toluene were blended and thoroughly mixed and stirred to prepare a release agent. The release agent thus obtained was coated on a polyethylene terephthalate (PET) film having a thickness of 49 μm using a gravure coating machine so that the film thickness after drying was 1 μm, dried at 120° C. for 2 minutes, and then removed. A 50 μm release sheet RS1 with a mold layer was obtained. The pressure-sensitive adhesive composition C1 was applied onto the release layer of the release sheet RS1 so that the thickness Ta after drying was 50 μm. After coating, the adhesive layer was formed by drying at 100° C. for 3 minutes. Next, a 50 μm PET film (G2L, manufactured by Toyobo Co., Ltd.) was attached to the exposed surface of the adhesive layer to obtain a test piece having a configuration of release sheet RS1/adhesive layer L1/PET film. Then, the peel force was obtained when the release sheet RS1 was peeled from the adhesive layer at a peel angle of 180° and a peel speed of 300 mm/min under an environment of 23° C. and a relative humidity of 50%.

d-2. Release sheets RS2 to RS24
Release sheets RS2 to RS2 were prepared in the same manner as for release sheet RS1, except that the composition of the release agent, the thickness of the release agent after drying on the base material, and the type and thickness of the base material were changed as shown in Table 3. RS24 was obtained. Table 3 also shows the peel strength of each release sheet to the adhesive layer L1 by the same method as for the release sheet RS1.
Symbols in Table 3 are as follows.
Silicone A: KS-847 (manufactured by Shin-Etsu Silicone Co., Ltd.)
Silicone B: DOWSIL (registered trademark) LTC755 Coating (manufactured by Dow Toray)
Silicone C: KS-841 (manufactured by Shin-Etsu Silicone Co., Ltd.)
Silicone D: KS-830E (manufactured by Shin-Etsu Silicone Co., Ltd.)
Silicone E: DOWSIL LTC 759 Coating (manufactured by Dow Toray)
Platinum catalyst: platinum (0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex solution (manufactured by Sigma-Aldrich)

(e) Production Example of Adhesive Sheet Roll e-1. Example 1
A coating machine equipped with a heavy release sheet supply section, a die coater head, a drying oven, a light release sheet and a laminator was used for the production of the adhesive sheet roll. First, a heavy release sheet roll (release sheet RS3, size width 1100 mm × 100 m) is set in the heavy release sheet supply unit, and the adhesive composition C1 is applied to the release layer of the heavy release sheet to a thickness of Ta after drying. was 25 μm. After coating, the adhesive layer was formed by drying at 100° C. for 3 minutes. The coating layer was provided with 25 mm adhesive layer non-formed portions at both ends in the width direction of the heavy release sheet.

Next, a light release sheet roll (release sheet RS11, size width 1100 mm x length 100 m) is set in the light release sheet supply unit, and the release layer surface of this light release sheet is laminated to the exposed surface of the adhesive layer described above. , to obtain an adhesive sheet S1 having a structure of "heavy release sheet/adhesive layer/light release sheet". After that, after winding the adhesive sheet S1 around a winding core with a diameter of 3 inches and a length of 120 cm, it was aged for 1 week at a temperature of 25° C. and a relative humidity of 50% to obtain an adhesive sheet with a width of 1.1 m and a length of 100 m. An adhesive sheet roll with layers was obtained. The film thickness, peel strength, etc. were measured at the position of 50% of the length of the adhesive sheet roll (the position unwound by 50 m).

e-2. Examples 2-26, Comparative Examples 1-8
PSA sheet rolls of Examples and Comparative Examples were obtained in the same manner as in Example 1, except that the types of PSA composition, light release sheet, and heavy release sheet were changed as shown in Tables 4 to 6.

(g) Evaluation of adhesive sheet roll g-1. Observation of dents The adhesive sheet roll of each example and comparative example is unwound, the adhesive sheet is irradiated with a light source (230 VILS, manufactured by Ushio Inc.) from a distance of 100 cm in front, and the adhesive sheet is placed on a screen 100 cm behind. projected with Then, the screen was visually observed to evaluate the dents of the pressure-sensitive adhesive sheet according to the following criteria. A dent that can be visually counted was counted as one dent having a major diameter of 0.5 mm or more.
5: Less than 50 dents/ ^m2 .
4: The number of dents is 50/ ^m2 or more and less than 100/ ^m2 .
3: The number of dents is 100/m ² or more and less than 300/m ² .
2: The number of dents is 300/m ² or more and less than 500/m ² .
1: The number of dents is 500/m2 ^or more and less than 1000/ ^m2 .

g-2. Air Bubbles During Folding The pressure-sensitive adhesive sheet roll of each example and comparative example was unwound, the light release sheet was peeled off, and the exposed pressure-sensitive adhesive layer was laminated on a polyimide film.
Next, the heavy release sheet was peeled off from the adhesive layer, and the exposed adhesive layer was laminated to an easily adhesive PET film. This laminate was placed in an autoclave and held at 50°C for 20 minutes. Next, the laminate was taken out and left at 25° C. and 50% RH for 30 minutes, then cut into a size of 70 mm in width and 100 mm in length, and a test laminate consisting of easily adhesive PET film/adhesive layer/polyimide. got a body
Next, the test laminate is twisted left and right in a planar body no-load twist tester (manufactured by Yuasa System Equipment Co., Ltd.) in an atmosphere of 25 ° C. and 50% RH, and then twisted until it returns to the state before twisting. As one cycle, the same operation was performed for 200,000 cycles. The number of samples tested was N=5, and the appearance after the test was visually evaluated. Evaluation criteria are as follows. The number of air bubbles was visually determined, and those with a diameter of 100 μm or more were counted.
No air bubbles are seen in all 5:5 samples.
Air bubbles were seen in the 4:1 sample.
Air bubbles were seen in the 3:2 sample.
Bubbles were visible in the 2:3 sample.
Air bubbles were seen in the 1:4 samples or all samples.

g-3. Punching Yield Sheets were punched with a die (Thomson blade). The punched shape and size were A4. The processing yield is defined as the frequency of occurrence of cracks when punching is performed 20 times.
5: The number of occurrences of nausea is 1 or less.
4: The number of times of occurrence of nausea is 2 or more and 3 or less.
3: The number of times of occurrence of nausea is 4 times or more and 5 times or less.
2: The number of times of occurrence of nausea is 6 times or more and 7 times or less.
1: The number of times of occurrence of nausea is 8 times or more.

g-4. Deformation of Adhesive Layer after Bonding The light release sheet was peeled off from the adhesive sheet, and a 50 μm PET film (G2L, manufactured by Toyobo Co., Ltd.) was adhered as an adherend to prepare a test piece of width 1000 mm×length 1000 mm. A light source (230 VILS, manufactured by Ushio Inc.) was irradiated onto the test piece from a distance of 100 cm from the front, and the test piece was visually observed directly from a distance of 20 cm or less, and the floating of the adhesive layer was evaluated according to the following criteria. Note that the float is 0.5 mm or more. In addition, evaluation was made into 1 when the large float of 10 mm or more existed.
5: Less than 10 floats of less than 1 mm/m ² and less than 10 floats of 1 mm or more and less than 10 mm/m ² .
4: Less than 30 floats of less than 1 mm/m ² and less than 10 floats/m 2 of 1 mm or more and less than ¹⁰ mm.
3: Less than 30 floats of less than 1 mm/m ² and 10 floats/m 2 or more of 1 mm or more and less than ¹⁰ mm.
2: 30 or more floats of less than 1 mm/m ² , and less than 10 floats/m 2 of 1 mm or more and less than ¹⁰ mm.
1: Not corresponding to any of the above evaluations 2 to 5. Or 1 piece/ ^m2 or more of 10 mm or more float.

As shown in Comparative Example 1, problems were confirmed with the adhesive sheet roll in which the heavy release sheet was unwound, in terms of air bubbles and deformation of the adhesive layer after lamination. In addition, even if the peel force ratio Ph/Pl satisfies 2 to 6, the peel force Pl is outside the range of 0.02 to 0.30 N/25 mm, or the peel force Ph is 0.10 to 0.80 N/25 mm. As shown in Comparative Examples 2 and 3, it was confirmed that the pressure-sensitive adhesive sheet roll formed of the release sheet outside the range of 1. has a problem in the generation of air bubbles. Similarly, as shown in Comparative Examples 4, 5, and 7, it was confirmed that the pressure-sensitive adhesive sheet roll combined with the release sheet that did not satisfy the peel force ratio Ph/Pl of 2 to 6 had the problem of bubble generation. . As shown in Comparative Example 6, the occurrence of dents was confirmed in the adhesive sheet roll having an adhesive layer having a thickness of more than 150 μm. In addition, as shown in Comparative Examples 7 and 8, the pressure-sensitive adhesive sheet rolls in which the thickness of the light release sheet and the heavy release sheet are the same or the release sheets in which Tl>Th are combined have a problem of occurrence of dents. On the other hand, according to this example, it was confirmed that it is possible to provide a high-quality adhesive sheet roll that can suppress the generation of dents and air bubbles, has an excellent punching yield, and can suppress deformation of the adhesive layer after bonding.

1: winding core 2: foam layer 3: adhesive sheet 6: heavy release sheet 7: adhesive layer 8: light release sheet 10: adhesive sheet roll

Claims (7)

An adhesive sheet roll in which a long adhesive sheet is wound around a core,
The adhesive sheet has an adhesive layer with a thickness of 5 to 150 μm sandwiched between a light release sheet and a heavy release sheet,
In the adhesive sheet unwound from the adhesive sheet roll, the peel strength when the light release sheet is peeled from the adhesive layer at a peel angle of 180 ° and a peel speed of 300 mm / min in an environment of 23 ° C. and 50% relative humidity. Pl is 0.02 to 0.30 N / 25 mm,
After peeling the light release sheet from the adhesive layer, a 50 μm PET film is attached to the exposed adhesive layer, and the heavy release sheet is further removed from the adhesive layer at 23 ° C. and a relative humidity of 50%. The peel force Ph when peeled at 180 ° and the peel speed of 300 mm / min is 0.10 to 0.80 N / 25 mm,
Ph/Pl is 2 to 6,
The thickness Tl of the light release sheet is 25 to 100 μm,
The thickness Th of the heavy release sheet is 50 to 188 μm,
and the Tl < the Th,
The adhesive layer is an adhesive layer formed using an adhesive composition containing an adhesive resin composed of a (meth)acrylic copolymer (a),
The light release sheet and the heavy release sheet have a release layer formed from a silicone-based release agent on the bonding surface with the adhesive layer,
A pressure-sensitive adhesive sheet roll for a flexible display, wherein the light release sheet is provided on the outer side of the roll. 2. The pressure-sensitive adhesive sheet roll according to claim 1, wherein the standard deviation σ of the thickness of the pressure-sensitive adhesive sheet is 10% or less with respect to the layer thickness. The adhesive layer is
A gel fraction of 50 to 90% and a storage modulus at -30°C of 10 MPa or less,
The pressure-sensitive adhesive resin has a weight average molecular weight of 500,000 or more ,
The (meth)acrylic copolymer (a) is a linear or branched alkyl (meth) having a structural unit derived from an alicyclic (meth)acrylate monomer and/or an alkyl group having 8 to 20 carbon atoms. ) The pressure-sensitive adhesive sheet roll according to claim 1, which is a copolymer having structural units derived from acrylate monomers. The adhesive layer has a thickness of 25 to 150 μm,
2. The pressure-sensitive adhesive sheet roll according to claim 1, wherein the pressure-sensitive adhesive layer has a pressure-sensitive adhesive strength of 10 to 40 N/25 mm with respect to the polyimide base material. The pressure-sensitive adhesive sheet roll according to claim 1, wherein the pressure-sensitive adhesive composition contains a curing agent, and the curing agent is one selected from isocyanate compounds, epoxy compounds, aziridine compounds, carbodiimide compounds, and metal chelates. (Meth)acrylic copolymer (a) 100% by mass, linear alkyl ( 2. The pressure-sensitive adhesive sheet roll according to claim 1, wherein the structural unit derived from the meth)acrylate monomer is 10 to 75% by mass. A pressure-sensitive adhesive sheet for a flexible display, which is unwound from the pressure-sensitive adhesive sheet roll according to any one of claims 1 to 6 and punched.

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