JP2011102369A - Multilayer double-sided self-adhesive sheet having removability - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new double-sided self-adhesive sheet which can make removability compatible with reliability on a self-adhesive face with respect to occurrence of peeling, foaming or the like. <P>SOLUTION: The multilayer double-sided self-adhesive sheet has at least one intermediate layer other than a front side adhesive layer 1A and a rear side adhesive layer 1B, and is constructed in such a way that at least the one layer, the intermediate layer, can be chemically or physically deformed, and the intermediate layer is a deformation releasing layer 1C, that is, the intermediate layer and another layer can be released from each other by the deformation. Adherends X, Y are released from each other inside the double-sided self-adhesive sheet, that is, at an interface or at a layer different from self-adhesive interfaces with the adherends X, Y. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention uses a multilayer double-sided pressure-sensitive adhesive sheet having removability capable of adhering two members (adhered bodies) and capable of being peeled again after sticking, and such a multilayer double-sided pressure-sensitive adhesive sheet. Relates to the laminated body.

  In flat image display devices used for mobile phones, PHS machines, PDA terminals, portable game machines, personal computers, automobile navigators, digital cameras, etc., the surface of the image display unit is protected and touch panel functions are added. For the purpose, a light-transmissive protective member is often disposed on the light emitting side of the image display unit. At this time, if there is a gap, that is, an air layer, between the light-transmitting protective member and the image display unit, the emitted light from the image display unit causes interface reflection at the interface with the air layer and reaches the user. In addition to the loss of the emitted light, the external light also causes interface reflection at the air layer interface, so that the light transmittance of the light transmissive member is lowered, and the visibility of the image display image may be lowered. . In addition, in the configuration in which only the light transmissive member is disposed, there is a concern that the damaged light transmissive member may be scattered when an impact such as a drop is applied to the image display device.

  Therefore, a method has been disclosed in which the gap between the light-transmitting protective member and the image display unit is filled with an adhesive sheet to reduce interface reflection with the air layer to ensure visibility and prevent scattering at the time of breakage. Yes.

  In this way, when the light transmissive protective member and the image display unit are bonded together with an adhesive sheet and integrated, work mistakes such as air bubbles and foreign matters may be involved during the bonding work, so this mistake is corrected. For example, it may be necessary to re-peel to remove the image display device, or re-peel to recycle some of the members when the image display device is discarded. May require removability (reworkability).

  Conventionally, as an adhesive sheet having removability (reworkability), for example, in Patent Document 1, a liquid crystal in which a lower surface of a fixed electrode member of a transparent touch panel and an upper surface of a liquid crystal display are mounted through a transparent removable sheet. A display-integrated transparent touch panel is disclosed, and a sheet formed by forming a transparent polymer pressure-sensitive adhesive into a gel sheet is disclosed as the transparent re-peeling sheet.

  Further, in Patent Document 2, a transparent touch panel side transparent adhesive layer is formed on one surface of a transparent substrate, a display device side transparent adhesive layer is formed on the other surface, and the display surface of the display device together with the touch panel is reproduced. A double-sided PSA sheet is disclosed that is configured to be peelable. Specifically, by making the 180 ° peel adhesive force of the touch-panel-side transparent adhesive layer larger than that of the display-device-side transparent adhesive layer, it can be re-peeled from the display surface of the display device together with the touch panel. A configuration is disclosed.

  Further, Patent Document 3 is configured to be detachable from at least one of the touch panel and the display surface of the display device, and is optically isotropic. As a double-sided PSA sheet, re-peelable that can be demonstrated by making the adhesive force of the display device side adhesive layer to the display surface of the display device smaller than the adhesive force of the touch panel side adhesive layer to the adhesive surface of the touch panel The structure is disclosed.

Japanese Patent Laid-Open No. 10-260395 JP 2003-238915 A JP 2004-231723 A

Many of the conventional adhesive materials (for example, refer to Patent Documents 1 to 3) having removability (reworkability) are bonded between two members, for example, between a touch panel and a display device. In most cases, the adhesive surface or the adhesive surface between the display device and the adhesive material can be removed again.
However, since such an adhesive material needs to reduce the peeling force of the adhesive surface with the adherend in order to be re-peelable, there is a problem that the possibility of occurrence of peeling or foaming is increased. It was. That is, the re-peelability and the reliability related to the occurrence of peeling and foaming are in a trade-off relationship, and it is extremely difficult to achieve both.

  The subject of the present invention is a pressure-sensitive adhesive material capable of adhering two members (adhered bodies), and can achieve both removability and reliability in the pressure-sensitive adhesive surface such as peeling and foaming. The object is to provide a new double-sided PSA sheet.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have made the above-mentioned problems possible by making the inside of the double-sided pressure-sensitive adhesive sheet, that is, the interface or layer different from the pressure-sensitive adhesive interface with the adherend. The inventors have found that this can be solved, and have completed the present invention.

  The present invention is a multilayer double-sided pressure-sensitive adhesive sheet having at least one intermediate layer in addition to the front-side pressure-sensitive adhesive layer and the back-side pressure-sensitive adhesive layer, and the at least one intermediate-layer is chemically or physically deformed. Therefore, the present invention proposes a multilayer double-sided PSA sheet having a configuration that is a modified release layer that can be peeled off from the intermediate layer and other layers by the deformation.

  The multilayer double-sided pressure-sensitive adhesive sheet of the present invention includes a deformable release layer inside the multilayer structure, and the deformable release layer can be peeled off from other layers by being chemically or physically deformed. That is, by chemically or physically deforming the deformed release layer after adhering the adherend, it can be peeled off in the multilayer structure, that is, at the interface or layer different from the adhesive interface with the adherend. It is not necessary to reduce the peeling force of the pressure-sensitive adhesive layer, and it can be peeled again while reducing defects that can cause peeling or foaming.

  This deformation peeling layer preferably includes a portion protruding outward from the peripheral edge of the other layer. In this way, if the deformed release layer has a portion that protrudes outward from the peripheral edge of the other layer, it can be chemically or physically deformed starting from this protruding portion. For example, the protruding portion can be physically deformed more easily by pulling the protruding portion.

It is a perspective view for demonstrating the method of re-peeling using an example of the adhesive sheet which concerns on 1st Embodiment. It is sectional drawing for demonstrating the laminated structural example of the adhesive sheet which concerns on 1st-4th embodiment. It is sectional drawing for demonstrating the method of re-peeling using an example of the adhesive sheet which concerns on 2nd Embodiment. It is sectional drawing for demonstrating the method of re-peeling using an example of the adhesive sheet which concerns on 3rd Embodiment.

  Next, examples of embodiments of the present invention will be described, but the scope of the present invention is not limited to the embodiments described here.

The multilayer double-sided pressure-sensitive adhesive sheet (hereinafter referred to as “the present pressure-sensitive adhesive sheet”) according to this embodiment is a multilayer double-sided pressure-sensitive adhesive sheet having at least one intermediate layer in addition to the front surface side pressure-sensitive adhesive layer and the back surface side pressure-sensitive adhesive layer. The multilayer having a configuration in which at least one intermediate layer can be chemically or physically deformed and is a deformed release layer that can be peeled off from the intermediate layer by the deformation. It is a double-sided pressure-sensitive adhesive sheet.
In the present pressure-sensitive adhesive sheet, another layer may be interposed between the front-side pressure-sensitive adhesive layer, the back-side pressure-sensitive adhesive layer, and the intermediate layer.

The following examples can be given as means for forming the deformation release layer. However, if it can be chemically or physically deformed and the intermediate layer and other layers can be peeled by the deformation, it is limited to such means (embodiment). is not.
(1) It can be formed as a layer that can be physically torn and divided in at least one direction (first embodiment).
(2) It can be formed as a layer that has rubber elasticity and can be physically expanded and contracted in any direction in the area direction of the deformation peeling layer (second embodiment).
(3) It can be formed as a layer that can be chemically expanded and contracted in any direction in the area direction of the deformation peeling layer by heat (third embodiment).
(4) Only the deformation release layer can be formed as a layer having a property that can be dissolved and chemically deformed by a solvent (including water) (fourth embodiment).
Hereinafter, each embodiment will be described in detail.

<First Embodiment>
The pressure-sensitive adhesive sheet 1 according to the first embodiment is a multilayer double-sided pressure-sensitive adhesive sheet having at least one deformation peeling layer 1C in addition to the surface-side pressure-sensitive adhesive layer 1A and the back-side pressure-sensitive adhesive layer 1B. As shown in FIG. 1, the deformation peeling layer 1C is a layer that can be physically torn and divided in one direction in the area direction, for example, in the length direction or the width direction.
Moreover, it is preferable to laminate | peel release sheets 1D and 1E to the front side surface of 1 A of surface side adhesive layers, and the back side surface of the back surface side adhesive layer 1B, respectively.
Furthermore, it is possible to interpose layers other than those described above as appropriate.

  The deformable release layer 1 </ b> C has a property (also referred to as “hand tearability”) that can be physically torn in at least one direction of the area of the deformed release layer, and is divided into a large number in the area direction by such tearing. If possible, for example, as shown in FIG. 1, the area of the deformation release layer 1C can be reduced or eliminated by tearing the deformation release layer 1C sequentially from the side, thereby reducing the surface-side pressure-sensitive adhesive layer 1A. The side and the back side pressure-sensitive adhesive layer 1B side can be divided and peeled off. In this way, the front-side pressure-sensitive adhesive layer 1A side and the back-side pressure-sensitive adhesive layer 1B side can be divided by physical deformation of tearing the deformation peeling layer 1C.

(Deformation peeling layer 1C)
The deformation release layer 1C is formed in at least one direction by forming a sheet of cellophane, polyester, polystyrene block copolymer, nylon, polyolefin, or the like oriented, that is, stretched, in at least one direction. It can be physically tearable.
In addition, the film formed from any resin such as polyester, polystyrene block copolymer, nylon, polyolefin, etc. can be torn in one direction by embossing, embossing, ruled line processing, etc. Can be formed.

The tear strength when tearing the deformed release layer 1C in at least one direction is preferably 5N or less, and more preferably 0.05N to 2N. If it is 0.05 N or more, tearing will not occur inadvertently during handling of the adhesive sheet, and if the tear strength is 5 N or less, workability during tearing will not be inferior. More preferable.
Here, the tear strength is a value measured according to JIS K 6972, that is, a width of 4
Prepare a test piece of 0 mm x 150 mm in length, make a 75 mm incision in the length direction from the center of the short piece, and attach it to the tensile tester so that both sides of the incision of the test piece are front and back, at a tensile speed of 200 mm / min. It is intended for weighting when tearing.

  It is preferable that 1 C of deformation | transformation peeling layers are provided with the part protruded outside from the peripheral part of 1 A of surface side adhesive layers and the back surface side adhesive layer 1B. The deformation peeling layer 1C can be torn off from the protruding portion, and the work of tearing and separating the deformation peeling layer 1C can be further facilitated.

(Surface side adhesive layer 1A, back side adhesive layer 1B)
Both the front-side pressure-sensitive adhesive layer 1A and the back-side pressure-sensitive adhesive layer 1B can be formed in the same manner as currently known pressure-sensitive adhesives.

  The composition of the pressure-sensitive adhesive can be arbitrarily selected. In order to adjust the peel strength of the pressure-sensitive adhesive layer, in other words, the pressure-sensitive adhesive strength, for example, the glass transition temperature of the main polymer constituting the pressure-sensitive adhesive layer, the amount of polar components / aggregation components In addition to adjusting the amount of addition and the amount of crosslinking agent added, it can be controlled by appropriately adding a tackifier or the like.

  As the base polymer (main agent) constituting the adhesive layer, for example, acrylic, silicone, rubber, polyurethane, and polyester polymers can be cited as the main agent of the adhesive. Above all, acrylic, especially acrylic ester polymers (including copolymers) are used as the base polymer (main agent) in terms of transparency, durability, and cost, and this is crosslinked with a thermal crosslinking agent or UV crosslinking agent. It is preferable to form an adhesive layer.

Examples of acrylic monomers and methacrylic monomers used to synthesize acrylic ester polymers include 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, n-butyl acrylate, isodecyl acrylate, ethyl acrylate, and the like. . These main monomers include cross-linkable monomers such as hydroxyethyl acrylate, acrylic acid, itaconic acid, glycidyl acrylate, glycidyl methacrylate, methylol acrylamide, maleic anhydride, methyl methacrylate, methyl acrylate, acrylamide, acrylonitrile, methacrylonitrile, vinyl acetate. And highly agglomerated monomers such as styrene, fluorine acrylate and silicone acrylate, and functional group-containing monomers.
As the polymerization treatment using these monomers, known polymerization methods such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization and the like can be employed. In this case, a thermal polymerization initiator or photopolymerization is used according to the polymerization method. An acrylic ester copolymer can be obtained by using a polymerization initiator such as an initiator.

Among them, in order to obtain a highly reliable pressure-sensitive adhesive layer, it is preferable that the weight average molecular weight in the above-described acrylate ester copolymer is high in a range not impairing processability, and those having about 100,000 to 1,000,000 are preferable. preferable. If the molecular weight is too low, the fluidity is too high, the cohesive force is insufficient, and the holding force and adhesion force to the adherend tend to be impaired.
The glass transition temperature (theoretical Tg) of the acrylate copolymer is preferably -70 ° C to 0 ° C, more preferably -55 ° C to 0 ° C. A material having a theoretical Tg that is too low has a low content of highly agglomerated components and highly polar components in the polymer, and as a result, tends to be inferior in holding power and adhesion to the adherend. On the other hand, if the theoretical Tg is too high, the adhesive strength is inferior, and the pressure-sensitive adhesiveness at room temperature is impaired.

  In order to impart adhesive strength and durability to the adhesive layer, various modifiers such as silane coupling agents, antioxidants, deterioration inhibitors, ultraviolet absorbers, tackifiers, etc. The physical properties may be adjusted as appropriate.

(Release sheets 1D, 1E)
As the release sheets 1D and 1E, a sheet obtained by performing release treatment on one surface of the support sheet can be used as appropriate.

However, after laminating the surface-side pressure-sensitive adhesive layer 1A and the back-side pressure-sensitive adhesive layer 1B with the release sheets 1D and 1E, the surface-side pressure-sensitive adhesive layer 1A and the back-side-side pressure-sensitive adhesive are irradiated by irradiating light through the release sheets 1D and 1E. When the layer 1B is cured, it is necessary to use a transparent polymer sheet for the support sheets of the release sheets 1D and 1E.
Transparent polymer sheets include, for example, polyesters such as polyethylene terephthalate and polyethylene naphthalate, as well as various polyolefin materials such as acrylic, vinyl chloride, polycarbonate, polystyrene, polyurethane, polyethylene, polypropylene, and TAC. The thing which has a film etc. as a main component can be illustrated.

  For example, silicone resin, fluorine resin, amino alkyd resin, polyester resin, paraffin wax, acrylic resin, urethane resin, melamine resin, urea resin, urea-melamine series, cellulose, benzoguanamine, and surfactant A single or a mixture of these organic solvents (including water) or a paint dissolved in water is applied by a normal printing method such as gravure printing, screen printing, or offset printing. It may be formed by drying (cured on a curable coating such as a thermosetting resin, an ultraviolet curable resin, an electron beam curable resin, or a radiation curable resin). In particular, it is preferable to perform a release treatment with a silicone, a fluorine compound, an alkyd resin release agent or the like.

  The peel strength of the release sheets 1D and 1E is, for example, a resin used for the release treatment, for example, a resin that constitutes both sides of the silicone compound by adjusting the skeleton and addition amount, the degree of crosslinking, etc. It can be adjusted by controlling the polarity difference and flow characteristics.

  The thickness of the release layer formed by the release treatment is not particularly limited, and for example, it is preferably formed to about 0.05 μm to 2 μm. If it is 0.05 μm or more, there is no possibility that the mold release performance is lowered, and if the thickness of the coating film is 2 μm or less, there is no possibility that the coating film becomes too thick and curing of the coating film becomes insufficient. It is preferable because the release agent component does not easily migrate to and the release performance does not change with time.

  In addition, from the viewpoint of workability such as ease of peeling of the release sheets 1D and 1E, it is preferable that the release sheets 1D and 1E have different peel strengths. For example, when the peel strength between the release sheet 1D and the front-side pressure-sensitive adhesive layer 1A is made stronger than the peel strength between the release sheet 1E and the back-side pressure-sensitive adhesive layer 1B, the release sheet 1E is first peeled off. Adhesive surface of the adhesive layer 1B is adhered to the adherend X, then the release sheet 1D is peeled off, and the adhesive surface of the back side adhesive layer 1A is adhered to the adherend Y, and the adherends X and Y If it is made to adhere | attach, it can adhere | attach more easily.

(Lamination method)
The pressure-sensitive adhesive composition is applied to the release-treated surface of the release sheet 1D and dried to form the surface-side pressure-sensitive adhesive layer 1A, and the release-treated surface of another release sheet 1D is laminated and laminated thereon, and then as necessary. Then, the surface-side pressure-sensitive adhesive layer 1A may be cured.
On the other hand, the pressure-sensitive adhesive composition is applied to the release-treated surface of the release sheet 1E and dried to form the surface-side pressure-sensitive adhesive layer 1B, and the release-treated surface of another release sheet 1E is laminated and laminated thereon, and then necessary Accordingly, the surface-side pressure-sensitive adhesive layer 1B may be cured.
Next, the modified release layer 1C is configured so as to be sandwiched between the adhesive surface of the front-side pressure-sensitive adhesive layer 1A from which one release sheet 1D has been peeled off and the adhesive surface of the back-side pressure-sensitive adhesive layer 1B from which one release sheet 1E has been peeled off. By sticking the sheets to be bonded, the present adhesive sheet 1 made of 1D / 1A / 1C / 1B / 1E can be formed as shown in FIG.

<Second Embodiment>
The pressure-sensitive adhesive sheet 2 according to the second embodiment is a multilayer double-sided pressure-sensitive adhesive sheet having at least one deformation peeling layer 2C in addition to the surface-side pressure-sensitive adhesive layer 2A and the back-side pressure-sensitive adhesive layer 2B. The release layer 2C is provided with rubber elasticity and is a layer that can be physically expanded and contracted in any direction in the area direction of the deformation release layer 2C.
Moreover, it is preferable to laminate | peel release sheets 2D and 2E to the front side surface of 2 A of surface side adhesive layers, and the back side surface of 2 A of back side adhesive layers, respectively.
Furthermore, it is possible to interpose layers other than those described above as appropriate.

If the deformation release layer 2C has rubber elasticity and can be physically expanded and contracted in any direction in the area direction of the deformation release layer 2C, as shown in FIG. When the deformation release layer 2C is stretched, the deformation stress when the deformation release layer 2C expands is changed between the deformation release layer 2C and other layers, for example, the front side adhesive layer 2A and the back side adhesive layer 2B. As a result, the adhesive layer is separated from other layers, for example, the front-side pressure-sensitive adhesive layer 2A and the back-side pressure-sensitive adhesive layer 2B, gradually from the location where the deformed peeling layer 2C is deformed, and finally the interface is It can peel and can divide the surface side adhesive layer 2A side and the back surface side adhesive layer 2B side.
Thus, by giving the physical deformation | transformation which expands / contracts the deformation | transformation peeling layer 2C physically, the surface side adhesive layer 2A side and the back surface side adhesive layer 2B side can be parted.

(Deformation peeling layer 2C)
The deformable release layer 2C is provided with rubber elasticity that extends beyond the original size by being formed using a resin that can exhibit rubber elasticity such as silicone elastomer, polystyrene elastomer, polyolefin elastomer, polyurethane elastomer, and the like. can do.

  It is preferable that 2 C of deformation | transformation peeling layers are provided with the part protruded outside from the peripheral part of 2 A of surface side adhesive layers and the back surface side adhesive layer 2B. The protruding part of the deformable release layer 2C can be grasped and pulled, and the work of pulling and peeling the deformable release layer 2C can be facilitated.

(Surface side adhesive layer 2A, back side adhesive layer 2B)
The front side pressure-sensitive adhesive layer 2A and the back side pressure-sensitive adhesive layer 2B may be formed in the same manner as the front side pressure-sensitive adhesive layer 1A and the back side pressure-sensitive adhesive layer 1B.

(Peeling sheet 2D / 2E)
The release sheets 2D and 2E may be formed in the same manner as the release sheets 1D and 1E.

(Lamination method)
The pressure-sensitive adhesive sheet 2 can be manufactured by laminating each layer in the same manner as the pressure-sensitive adhesive sheet 1.

<Third Embodiment>
The present pressure-sensitive adhesive sheet 3 according to the third embodiment is a multilayer double-sided pressure-sensitive adhesive sheet having at least one deformation peeling layer 3C in addition to the surface-side pressure-sensitive adhesive layer 3A and the back-side pressure-sensitive adhesive layer 3B. The release layer 3C is a layer that can be chemically expanded and contracted in any direction in the area direction of the deformation release layer 3C by heat.
Moreover, it is preferable to laminate | peel release sheets 3D and 3E to the front side surface of 3 A of surface side adhesive layers, and the back side surface of 3 A of back side adhesive layers, respectively.
Furthermore, it is possible to interpose layers other than those described above as appropriate.

If the deformable release layer 3C can be expanded and contracted by heat in any direction in the area direction of the deformable release layer 3C, that is, by a chemical reaction, the deformable release layer 3C is heated, for example, as shown in FIG. As described above, the deformation release layer 3C can be contracted in any direction in the area direction, and therefore, the deformation stress when the deformation release layer 3C contracts is affected by the deformation release layer 3C and other layers, for example, the surface Adhesive strength with the interface between the side pressure-sensitive adhesive layer 3A and the back-side pressure-sensitive adhesive layer 3B is increased, and as a result, other layers, for example, the front-side pressure-sensitive adhesive layer 3A and the back side gradually from the deformed release layer 3C. Separating from the side pressure-sensitive adhesive layer 3B, the interface is finally peeled off, so that the surface-side pressure-sensitive adhesive layer 3A side and the back-side pressure-sensitive adhesive layer 3B side can be separated.
Thus, the surface side adhesive layer 3A side and the back surface side adhesive layer 3B side can be divided by giving the chemical deformation of chemically expanding and contracting the deformation peeling layer 3C by heat.

(Deformation peeling layer 3C)
As the deformation release layer 3C, a currently known heat shrink film can be used. For example, it can be formed using a heat-shrinkable film made of a polystyrene, polyvinyl chloride, or polyester resin.
More specifically, a polystyrene block copolymer (for example, a polystyrene block copolymer comprising 55% by weight of styrene, 35% by weight of methyl methacrylate, and 10% by weight of butyl acrylate) is 4.0 in the TD direction at 110 ° C. A heat-shrinkable polystyrene film obtained by double-stretching can be used.
For details of the heat shrinkable film, see, for example, paragraphs [0009] to [0029] of JP-A-2005-171182.

(Surface side adhesive layer 3A, back side adhesive layer 3B)
The front side pressure-sensitive adhesive layer 3A and the back side pressure-sensitive adhesive layer 3B may be formed in the same manner as the front side pressure-sensitive adhesive layer 1A and the back side pressure-sensitive adhesive layer 1B.

(Peeling sheet 3D / 3E)
The release sheets 3D and 3E may be formed in the same manner as the release sheets 1D and 1E.

(Lamination method)
The pressure-sensitive adhesive sheet 3 can be manufactured by laminating each layer in the same manner as the pressure-sensitive adhesive sheet 1.

<Fourth Embodiment>
The present pressure-sensitive adhesive sheet 4 according to the fourth embodiment is a multilayer double-sided pressure-sensitive adhesive sheet having at least one deformation peeling layer 4C in addition to the surface-side pressure-sensitive adhesive layer 4A and the back-side pressure-sensitive adhesive layer 4B. The release layer 4C is a layer having a property that it can be dissolved and chemically deformed by a solvent (including water).
Moreover, it is preferable to laminate | peel release sheets 4D and 4E to the front side surface of 4 A of surface side adhesive layers, and the back side surface of the back surface side adhesive layer 4B, respectively.
Furthermore, it is possible to interpose layers other than those described above as appropriate.

If only the deformation release layer 4C can be dissolved and chemically deformed by a solvent (including water), that is, can be deformed by a chemical reaction, for example, the adhesive sheet is immersed in a solvent (including water) or applied. If the deformation peeling layer 4C can be dissolved by contacting with a solvent (including water), the front side pressure-sensitive adhesive layer 4A side and the back side pressure-sensitive adhesive layer 4B side can be divided.
In this way, the surface-side pressure-sensitive adhesive layer 4A side and the back-side pressure-sensitive adhesive layer 4B side can be separated by a chemical deformation called a chemical reaction with a solvent (including water).

(Deformation peeling layer 4C)
In order to make the deformable release layer 4C water-soluble, various hydrophilic compounds such as hydroxyethylcellulose, starch, carboxymethylcellulose, alginic acid / hyaluronic acid / polyglutamic acid salts, chitosan, polylysine, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide A water-soluble sheet may be formed on the basis of a resin composition containing a polyacrylic acid, polyethylene glycol, polydioxolane, polyethyleneimine or the like, or a modified polyalkylene oxide, and the like.
More specifically, an ultraviolet curable resin composition obtained by mixing urethane acrylate, polyoxyethylene-modified trimethylolpropane triacrylate, hydroxybutyl acrylate, and photoinitiator has a thickness after curing with an applicator of 50 μm. If it is coated and UV-irradiated, a water-soluble sheet can be produced.

  Moreover, as an example of the material which melt | dissolves in an organic solvent, for example, the adhesive resin (75 weight part of butyl acrylate / 20 weight part of methyl methacrylate / 3 weight part of acrylic acid) formed by copolymerizing an acrylic monomer is used as a metal chelating agent ( For example, a sheet obtained by ion crosslinking with zinc acetylacetonate) can be used. This is because there is no cross-linking structure due to chemical bonding, so that the cross-linking structure is dissociated and the resin layer is gradually dissolved by impregnation with a highly polar organic solvent (including water) (for example, tetrahydrofuran).

  It is preferable that the deformation peeling layer 4C includes a portion protruding outward from the peripheral edge portion of the front surface side adhesive layer 4A and the back surface side adhesive layer 4B. It can be gradually dissolved from the protruding part of the deformation release layer 4C.

(Surface side adhesive layer 4A, back side adhesive layer 4B)
The front side pressure-sensitive adhesive layer 4A and the back side pressure-sensitive adhesive layer 4B may be formed in the same manner as the front side pressure-sensitive adhesive layer 1A and the back side pressure-sensitive adhesive layer 1B.

(Peeling sheets 4D and 4E)
The release sheets 4D and 4E may be formed in the same manner as the release sheets 1D and 1E.

(Lamination method)
The pressure-sensitive adhesive sheet 4 can be manufactured by laminating each layer in the same manner as the pressure-sensitive adhesive sheet 1.

<Laminated body>
By adhering two members using any one of the present pressure-sensitive adhesive sheets 1 to 4, a laminate composed of the two members and any one of the present pressure-sensitive adhesive sheets 1 to 4 can be formed.

For example, in a liquid crystal display device, a plasma display device, a laminated glass, a solar cell panel, etc., the synthetic resin plates are bonded to each other, the glass to each other, or the synthetic resin plate and the glass are bonded using any one of the adhesive sheets 1 to 4 Can do.
And in any case, when it wants to peel after adhesion | attachment, it can be made to peel by deform | transforming any of the deformation | transformation peeling layers 1C-4C.

<Image display device>
Moreover, an image display apparatus can be comprised by adhere | attaching between two members which comprise an image display apparatus using either of this adhesive sheets 1-4.
For example, any two optical members of a transparent cover material, a touch panel material, and an image display device are bonded using any one of the pressure-sensitive adhesive sheets 1 to 4, and the image display device is configured by tightly integrating them. can do.
Since the image display device configured as described above can be peeled by deforming any one of the deformation peeling layers 1C to 4C, it is peeled not from the interface between the optical member and the adhesive material but from the inside of the double-sided pressure-sensitive adhesive sheet. Therefore, each of the transparent cover material, the touch panel material, and the image display device can be reused.
Further, even after the transparent cover material and the image display device are bonded together, it is possible to repair or replace due to a sticking error or long-term use.

1, 2, 3, 4 Multi-layer double-sided PSA sheet 1A, 2A, 3A, 4A Front side adhesive layer 1B, 2B, 3B, 4B Back side adhesive layer 1C, 2C, 3C, 4C Deformation release layer 1D, 2D, 3D 4D release sheets 1E, 2E, 3E, 4E release sheets X, Y

Claims (8)

  A multilayer double-sided pressure-sensitive adhesive sheet having at least one intermediate layer in addition to the front-side pressure-sensitive adhesive layer and the back-side pressure-sensitive adhesive layer, wherein at least one intermediate layer can be chemically or physically deformed. A multilayer double-sided pressure-sensitive adhesive sheet comprising a structure which is a modified release layer that allows the intermediate layer and other layers to be peeled by the deformation.   2. The multilayer double-sided pressure-sensitive adhesive sheet according to claim 1, wherein the deformation release layer includes a portion protruding outward from a peripheral edge of another layer.   The multilayer double-sided pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the deformation release layer is physically tearable in at least one direction and can be divided.   3. The multilayer double-sided pressure-sensitive adhesive sheet according to claim 1, wherein the deformation release layer has rubber elasticity and can be physically expanded and contracted in any direction in the area direction of the deformation release layer.   3. The multilayer double-sided pressure-sensitive adhesive sheet according to claim 1, wherein the deformation release layer can be chemically expanded and contracted in any direction in the area direction of the deformation release layer by heat.   3. The multilayer double-sided pressure-sensitive adhesive sheet according to claim 1, wherein only the deformation release layer has a property of being dissolved and chemically deformed by a solvent (including water).   The laminated body which uses the multilayer double-sided adhesive sheet in any one of Claims 1-6 for adhesion between two members. The image display apparatus which uses the multilayer double-sided adhesive sheet in any one of Claims 1-6 for sticking between the members in an image display apparatus.

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