WO2019225649A1 - Adhesive sheet - Google Patents

Abstract

Provided is an adhesive sheet having an adhesive agent layer. The adhesive agent layer has an adhesive surface that is adherable to an adherend. The adhesive sheet has a peeling force-raising agent feed part: that is disposed at a location which is separated from the adhesive surface via a surface part on the adhesive surface side; and that is for feeding a peeling force-raising agent to the surface part.

Description

Adhesive sheet

The present invention relates to an adhesive sheet and an adhesive sheet peeling method. This application claims priority based on Japanese Patent Application No. 2018-099402 filed on May 24, 2018, the entire contents of which are incorporated herein by reference.

Generally, a pressure-sensitive adhesive (also referred to as a pressure-sensitive adhesive; the same shall apply hereinafter) is in the form of a soft solid (viscoelastic body) in a temperature range near room temperature and has a property of easily adhering to an adherend by pressure. Taking advantage of such properties, the adhesive is widely used in various fields in the form of a pressure-sensitive adhesive sheet with a support having a pressure-sensitive adhesive layer on the support or in the form of a support-less pressure-sensitive adhesive sheet having no support. It's being used. Patent document 1 is mentioned as technical literature regarding an adhesive.

Japanese Patent Application Publication No. 2013-216726

Adhesives are required to have various properties depending on the application. Some of these characteristics are difficult to achieve at a high level, for example, when one characteristic tends to be improved, the other characteristic tends to decrease. As an example of the characteristics that are difficult to achieve such compatibility, there are an adhesive force to the adherend and reworkability. The above-mentioned rework means that when the adhesive sheet is affixed to the adherend, it may fail to adhere (position misalignment, generation of wrinkles or bubbles, biting of foreign matter, etc.), or a problem with the adherend after application of the adhesive sheet. It means that the adhesive sheet is peeled off from the adherend and reapplied in the case where is found. In particular, when the adherend is brittle or thin, the peel strength of the adhesive sheet from the adherend (that is, the adhesive strength to the adherend) is reduced in order to prevent damage and deformation of the adherend due to rework. Since it is required to suppress, it is not easy to realize an adhesive sheet having both good reworkability and high adhesive force.

Patent Document 1 discloses a property that foaming and peeling do not occur even when exposed to high temperature or high temperature and high humidity conditions, and a pressure-sensitive adhesive on the adherend even when exposed to high temperature conditions after being attached to the adherend. It is described that an adhesive composition contains an organopolysiloxane having a specific structure and / or a hydrolyzed condensate thereof in order to achieve both a property (non-glue residue) that can be removed without leaving a residue. Yes. However, non-glue residue and low peel strength are different properties. In Patent Document 1, it is not considered to reduce the peeling force during reworking in order to prevent damage to the adherend.

Accordingly, an object of the present invention is to provide a pressure-sensitive adhesive sheet having both good reworkability and high adhesive strength (peeling strength).

According to this specification, an adhesive sheet having an adhesive layer is provided. The pressure-sensitive adhesive layer has a pressure-sensitive adhesive surface that can be attached to an adherend. In the pressure-sensitive adhesive sheet, a peeling force increasing agent supply unit that supplies a peeling force increasing agent to the surface portion is provided at a location separated from the pressure-sensitive adhesive surface via the surface portion on the pressure-sensitive adhesive surface side.

In the pressure-sensitive adhesive sheet having such a configuration, a peeling force increasing agent supply section (hereinafter, simply referred to as “supply section”) is disposed at a location separated from the pressure-sensitive adhesive surface via the surface portion. For a while after being affixed to the film, the effect of the peel strength increasing agent does not appear, and good reworkability can be exhibited during that time. After that, the peeling force increasing agent supplied from the supply part to the surface part penetrates the surface part and reaches the adhesive surface, and exhibits an effect of improving the peeling force at the interface between the adhesive surface and the adherend. The peel strength of the pressure-sensitive adhesive sheet can be improved. Therefore, according to the pressure-sensitive adhesive sheet having the above configuration, both good reworkability and high peeling force can be achieved.

As the above-mentioned peeling force increasing agent, those containing the functional group X and the functional group Y in one molecule can be preferably used. For example, the functional group X is a group that reacts with a hydroxyl group that may be present on the adherend surface or a precursor thereof, and the functional group Y is a group that is reactive with the functional group y contained in the surface portion. A power raising agent is preferred. According to the peeling force increasing agent having such a structure, the peeling force can be effectively improved. It is preferable that the peeling force increasing agent is contained in the supply unit in a free form. The peeling force increasing agent contained in the supply part in such a form can efficiently move from the supply part to the surface part, and can effectively contribute to the improvement of the peeling force.

As a suitable example of the peeling strength increasing agent containing the functional group X and the functional group Y in one molecule, there is a peeling strength increasing agent in which the functional group X is an alkoxysilyl group. According to the peel strength increasing agent having an alkoxysilyl group, the peel strength from the adherend can be effectively improved.

In some embodiments of the pressure-sensitive adhesive sheet disclosed herein, the pressure-sensitive adhesive layer includes an A layer constituting the pressure-sensitive adhesive surface and a B layer disposed on the back side of the A layer, and the B layer is the above-described It is comprised so that it may function as a peeling force raising agent supply part. The pressure-sensitive adhesive sheet having such a structure exhibits a peeling force mainly according to the characteristics of the A layer at the initial stage of application to the adherend of the pressure-sensitive adhesive surface (that is, the surface of the A layer). Good reworkability can be exhibited by appropriately selecting the agent. Then, when the peeling force increasing agent in the B layer moves to the A layer, the peeling force from the adherend of the pressure-sensitive adhesive sheet can be greatly increased. This makes it possible to achieve both good reworkability and high peeling force.

In some embodiments of the pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer includes the layer A and the layer B, the concentration C _B [wt%] of the peeling force increasing agent in the layer B is the value in the layer A. It is preferably higher than the concentration C _A [wt%] of the peel strength raising agent. According to the pressure-sensitive adhesive sheet having such a configuration, after being attached to the adherend, the peeling force increasing agent in the B layer can be efficiently transferred to the A layer, thereby effectively improving the peeling force. .

In some embodiments, the glass transition temperature Tg _A of the base polymer of the A layer is preferably −10 ° C. or lower. The glass transition temperature Tg _B of the base polymer of the B layer is preferably higher than the glass transition temperature Tg _A of the base polymer of the A layer. The pressure-sensitive adhesive sheet having such a configuration easily stores the peeling force increasing agent in the B layer before being attached to the adherend, and after being attached to the adherend, the peeling force increasing agent in the B layer. Can be efficiently supplied to the A layer to effectively improve the peeling force, which is preferable.

In some embodiments, the thickness of the A layer can be in the range of 2 μm to 100 μm, for example. When the thickness of the A layer is not too small, good reworkability can be reliably exhibited at the initial stage of application. When the thickness of the A layer is not too large, the effect of the peeling force increasing agent supplied from the B layer after application to the adherend is exhibited at an appropriate timing, and the peel force from the adherend is improved. Can do.

The pressure-sensitive adhesive sheet according to some embodiments has a normal peeling force FN1 of 2.8 N / minute measured at a tensile speed of 60 mm / min and a peeling angle of 180 degrees after 1 day at room temperature after the pressure-sensitive adhesive surface is attached to an adherend. It is preferable that it is cm or less. Further, the pressure-sensitive adhesive sheet has a normal peeling force FN30 of 3.0 N / cm or more measured at a tensile speed of 60 mm / min and a peeling angle of 180 degrees after 30 days at room temperature after the pressure-sensitive adhesive surface is attached to an adherend. Preferably there is. According to the pressure-sensitive adhesive sheet satisfying the above FN1 and FN30, good reworkability is exhibited at the initial stage of application, and then the reliability of bonding with the adherend can be increased by improving the peeling force.

In the pressure-sensitive adhesive sheet disclosed herein, the increase rate of the normal peeling force FN30 [N / cm] with respect to the normal peeling force FN1 [N / cm] is preferably 20% or more. According to the pressure-sensitive adhesive sheet satisfying the above FN1 and FN30, good reworkability is exhibited at the initial stage of application, and then the reliability of bonding with the adherend can be increased by improving the peeling force.

The pressure-sensitive adhesive sheet disclosed herein has the pressure-sensitive adhesive surface attached to an adherend and drops one drop of water onto the adherend after one day at room temperature. The water peeling force FW1 measured under the conditions of a tensile speed of 60 mm / min and a peeling angle of 180 degrees without supplying new water after entering one end of the interface may be less than 1.0 N / cm. preferable. Such an adhesive sheet can peel off the adhesive sheet from the adherend with a very light force by peeling off the adhesive sheet using an aqueous liquid at the initial stage of application. Thereby, the load concerning a to-be-adhered body at the time of the said peeling can be reduced, and a damage and a deformation | transformation of a to-be-adhered body can be prevented better.

The pressure-sensitive adhesive sheet disclosed herein has the pressure-sensitive adhesive surface attached to an adherend, and after 30 days at room temperature, a drop of water is dropped onto the adherend, and the water is added to the pressure-sensitive adhesive layer and the adherend. The water peeling force FW30 measured under the conditions of a pulling speed of 60 mm / min and a peeling angle of 180 degrees without supplying new water after entering one end of the interface of the water should be 2.0 N / cm or more. preferable. Such a pressure-sensitive adhesive sheet can sufficiently improve the water resistance of bonding over time, and thus has excellent bonding reliability.

Further, according to this specification, there is provided a member with a pressure-sensitive adhesive sheet including any pressure-sensitive adhesive sheet disclosed herein and a member bonded to the pressure-sensitive adhesive surface. Such a member with a pressure-sensitive adhesive sheet can suppress an increase in peeling force for a while after the pressure-sensitive adhesive sheet is adhered to an adherend, so that, for example, reworkability when the pressure-sensitive adhesive sheet is bonded to the member is It can be good.

Note that a combination of the above-described elements as appropriate can also be included in the scope of the invention for which protection by patent is sought by this patent application.

Drawing 1 is a sectional view showing typically the composition of the adhesive sheet concerning one embodiment. FIG. 2 is a cross-sectional view schematically showing the configuration of the pressure-sensitive adhesive sheet according to another embodiment. FIG. 3 is a cross-sectional view schematically showing a member with an adhesive sheet in which an adhesive sheet according to another embodiment is attached to the member.

Hereinafter, preferred embodiments of the present invention will be described. Note that matters other than matters specifically mentioned in the present specification and necessary for the implementation of the present invention are based on the teachings on the implementation of the invention described in the present specification and common general technical knowledge at the time of filing. Can be understood by those skilled in the art. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field. In the following drawings, members / parts having the same action may be described with the same reference numerals, and redundant descriptions may be omitted or simplified. Further, the embodiments described in the drawings are schematically illustrated in order to clearly explain the present invention, and do not necessarily accurately represent the size and scale of a product actually provided.

In this specification, “acrylic polymer” refers to a polymer derived from a monomer component containing more than 50% by weight of an acrylic monomer. The acrylic monomer refers to a monomer derived from a monomer having at least one (meth) acryloyl group in one molecule. In addition, in this specification, “(meth) acryloyl” means acryloyl and methacryloyl comprehensively. Similarly, “(meth) acrylate” means acrylate and methacrylate, and “(meth) acryl” generically means acrylic and methacryl.

<Configuration example of adhesive sheet>
One structural example of the adhesive sheet disclosed here is shown in FIG. This pressure-sensitive adhesive sheet 1 includes a pressure-sensitive adhesive layer 110 having one surface 110A attached to an adherend and a support 20 laminated on the other surface of the pressure-sensitive adhesive layer 110. It is configured as an adhesive pressure-sensitive adhesive sheet. The pressure-sensitive adhesive layer 110 is fixedly bonded to one surface 20A of the support 20. As the support 20, for example, a plastic film such as a polyester film can be preferably used. The pressure-sensitive adhesive layer 110 has a two-layer structure including an A layer 112 constituting one surface (adhesive surface) 110 </ b> A and a B layer 114 stacked on the back side of the A layer 112.

For example, as shown in FIG. 1, the pressure-sensitive adhesive sheet 1 before use (before sticking to an adherend) has a pressure-sensitive adhesive surface 110 </ b> A, at least the pressure-sensitive adhesive layer side having a peelable surface (peeling surface). It can be in the form of a pressure-sensitive adhesive sheet 150 with a release liner protected by Alternatively, the second surface 20B (the surface opposite to the first surface 20A, also referred to as the back surface) of the support 20 is a peeling surface, and the adhesive surface 110A comes into contact with the second surface 20B. The adhesive surface 110A may be protected by being wound or laminated.
The release liner is not particularly limited. For example, a release liner whose surface of a liner base material such as a resin film or paper is subjected to a release treatment, a fluorine-based polymer (polytetrafluoroethylene, etc.), a polyolefin resin (polyethylene, polypropylene, etc.) And a release liner made of a low adhesion material. For the release treatment, for example, a release agent such as silicone or long chain alkyl may be used. In some embodiments, a release-treated resin film can be preferably used as a release liner.

The pressure-sensitive adhesive sheet 1 shown in FIG. 1 can cause the B layer 114 to function as a peeling force increasing agent supply unit by, for example, containing a peeling force increasing agent in the adhesive constituting the B layer 114. Since the B layer 114 is separated from the surface (adhesive surface) 110A of the A layer via the A layer 112, the adhesive layer 110A is mainly attached for a while after being adhered to the adherend (eg, glass plate). Shows the peel force according to the characteristics of the A layer 112. Therefore, it is possible to exhibit good reworkability by appropriately selecting the pressure-sensitive adhesive constituting the A layer 112. Thereafter, the peeling force increasing agent in the B layer 114 as the peeling force increasing agent supply portion moves to the A layer 112 and further passes through the A layer 112 and reaches the adhesive surface 110A. Then, the peeling force increasing agent acts at the interface between the pressure-sensitive adhesive surface 110A and the adherend, whereby the peeling force of the pressure-sensitive adhesive sheet 1 from the adherend can be increased. Therefore, according to the pressure-sensitive adhesive sheet having the above configuration, both good reworkability and high peeling force can be achieved.

Another structural example of the pressure-sensitive adhesive sheet disclosed herein is shown in FIG. The pressure-sensitive adhesive sheet 2 includes a pressure-sensitive adhesive layer 10 having one surface 10A attached to an adherend and a support 20 laminated on the other surface 10B side of the pressure-sensitive adhesive layer 10. It is configured as a single-sided adhesive sheet. The pressure-sensitive adhesive layer 10 has a single layer structure. That is, the entirety of the pressure-sensitive adhesive layer 10 is constituted by the A layer constituting one surface (pressure-sensitive adhesive surface) 10 </ b> A of the pressure-sensitive adhesive layer 10.
The pressure-sensitive adhesive sheet 2 shown in FIG. 2 further includes a peeling force increasing agent layer 40 disposed between the pressure-sensitive adhesive layer 10 and the support 20. The peeling force increasing agent layer 40 contains a peeling force increasing agent, and is typically a non-adhesive layer. By supplying the peeling force increasing agent from the peeling force increasing agent layer 40 to the pressure sensitive adhesive layer 10, both good reworkability and high peeling force can be achieved in the same manner as the pressure sensitive adhesive sheet 1 shown in FIG. 1. The peeling force increasing agent layer 40 may be a layer substantially composed of a peeling force increasing agent. In addition, the peeling force increasing agent layer 40 is composed of a peeling force increasing agent, a binder resin, and the like from the viewpoint of uniformity of arrangement of the peeling force increasing agent and control of the transfer speed to the adhesive layer 10. It may be a layer containing other components. The content of the peeling force increasing agent in the peeling force increasing layer 40 may be, for example, 5% by weight or more, 10% by weight or more, 25% by weight, 50% by weight, 70% by weight or 85% by weight. % Or more, or substantially 100% by weight.
The peeling force increasing agent layer 40 is a surface of the support 20 made of, for example, a liquid composition in which a peeling force increasing agent and other components (binder resin or the like) that can be used as necessary are dissolved or dispersed in an appropriate solvent. It is possible to dispose between the pressure-sensitive adhesive layer 10 and the support 20 by attaching the support 20 to the back surface of the pressure-sensitive adhesive layer 10. Alternatively, the liquid composition is applied to a peelable surface and dried to form a peel strength increasing agent layer 40, and the peel strength increasing agent layer 40 is bonded to the back surface of the pressure-sensitive adhesive layer 10 and transferred. The support 20 may be bonded together.
The pressure-sensitive adhesive sheet 2 before use (before sticking to an adherend) can be in the form of a pressure-sensitive adhesive sheet 50 with a release liner in which the pressure-sensitive adhesive surface 10A is protected with a release liner 30 as shown in FIG. Alternatively, the second surface 20B of the support 20 is a release surface, and the adhesive surface 10A is protected by being wound or laminated so that the adhesive surface 10A is in contact with the second surface 20B. May be.

As a modification of the configuration shown in FIG. 1, instead of including the peeling force increasing agent in the B layer 114, a layer similar to the peeling force increasing agent layer 40 in the pressure-sensitive adhesive sheet shown in FIG. A configuration in which the peeling force increasing agent layer is disposed between the B layer 114, a configuration in which such a peeling force increasing agent layer is disposed between the B layer 114 and the support 20, or a peeling force increasing agent layer is disposed at both of these locations. Configuration. Even in the pressure-sensitive adhesive sheet having such a configuration, a good rework property is exhibited for a while after the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet is attached to the adherend, and then supplied to the A layer 112 from the peeling force increasing agent layer. When the released peeling force increasing agent reaches the pressure-sensitive adhesive surface and increases the peeling force, both good reworkability and high peeling force can be achieved.

The pressure-sensitive adhesive sheet disclosed herein may be a support-less double-sided pressure-sensitive adhesive sheet composed of a pressure-sensitive adhesive layer. Such a support-less double-sided pressure-sensitive adhesive sheet can be used, for example, by bonding a support to the other surface of the pressure-sensitive adhesive layer.

The pressure-sensitive adhesive sheet disclosed herein can be a component of a member with a pressure-sensitive adhesive sheet in which a member is bonded to the pressure-sensitive adhesive surface. For example, the pressure-sensitive adhesive sheet 1 shown in FIG. 1 can be a component of a member 200 with a pressure-sensitive adhesive sheet in which a member 70 is bonded to one surface 110A of the pressure-sensitive adhesive layer 110, as shown in FIG. Instead of the pressure-sensitive adhesive sheet 1 shown in FIG. 1, a pressure-sensitive adhesive sheet 2 shown in FIG. 2 may be used. As said member, what the surface to which an adhesive sheet is affixed is a non-water-absorbing smooth surface is preferable. The member with the pressure-sensitive adhesive sheet having such a configuration can be easily reworked by applying a water peeling method, which will be described later, if necessary, when the pressure-sensitive adhesive sheet is attached to the member. The member can be, for example, a glass plate, a resin film, a metal plate, or the like.

<Peeling force increasing agent supply unit>
The pressure-sensitive adhesive sheet disclosed herein includes a pressure-sensitive adhesive layer having a pressure-sensitive adhesive surface that can be attached to an adherend, and a peeling force increasing agent supplying unit that supplies a peeling force increasing agent to the surface portion on the pressure-sensitive adhesive surface side. . The peeling force increasing agent supply unit is separated from the adhesive surface through the surface portion. Hereinafter, an embodiment in which the pressure-sensitive adhesive layer includes an A layer and a B layer and the B layer is an adhesive strength increasing agent supply unit will be described as a main example, but the intention is to limit the configuration of the pressure-sensitive adhesive sheet disclosed herein. Absent.

(Peeling strength increasing agent)
As the above-mentioned peeling force increasing agent, it can exert a function of increasing the peeling force from the adherend of the pressure-sensitive adhesive sheet by being supplied to the surface portion of the pressure-sensitive adhesive surface after the pressure-sensitive adhesive surface is attached to the adherend. The material can be appropriately selected and used. As the peeling force increasing agent, for example, a known silane coupling agent or crosslinking agent can be used. It is preferable that the peeling force increasing agent is contained in the peeling force increasing agent supply section in a free form. Typically, it is preferable that the peeling force increasing agent is not chemically bonded to other components that may be included in the supply unit. The peeling force increasing agent contained in the supply part in such a form can efficiently migrate from the supply part to the surface part, and can effectively contribute to the improvement of the peeling force.

The silane coupling agent is typically a compound that contains a functional group X and a functional group Y in one molecule, and the functional group X is an alkoxysilyl group. The alkoxysilyl group is a functional group having at least one alkoxy group on a silicon atom. By supplying a silane coupling agent to the surface portion of the pressure-sensitive adhesive layer after application to the adherend, the silanol groups produced by hydrolysis of the alkoxy group react with the hydroxyl groups on the adherend surface, thereby The peeling force from the adherend of the pressure-sensitive adhesive sheet can be increased. The alkoxysilyl group generates a silanol group that reacts with a hydroxyl group on the surface of the adherend by hydrolysis. Accordingly, the alkoxysilyl group is a precursor of a group that reacts with the hydroxyl group.

The alkoxy group constituting the alkoxysilyl group is typically a methoxy group or an ethoxy group. Usually, a methoxy group having higher hydrolyzability is preferable. The alkoxysilyl group may be a trialkoxysilyl group or a dialkoxysilyl group. From the viewpoint of enhancing the peeling force increasing effect, in some embodiments, a silane coupling agent having a trialkoxysilyl group can be preferably employed.

The functional group Y is, for example, an epoxy group, an amino group, an isocyanate group (which may constitute an isocyanurate body), an acetoacetyl group, a (meth) acryloyl group, a mercapto group, a vinyl group, a halogenated alkyl group, or the like. It can be. Examples of silane coupling agents having such a functional group Y include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- ( Epoxy group-containing silane coupling agents such as 3,4-epoxycyclohexyl) ethyltrimethoxysilane; for example, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, N- ( 2-aminoethyl) amino group-containing silane coupling agents such as 3-aminopropylmethyldimethoxysilane; isocyanate group-containing silane couplings such as 3-isocyanatopropyltriethoxysilane and tris (trimethoxysilylpropyl) isocyanurate Agent; For example, an acetoacetyl group-containing silane coupling agent such as acetoacetyl group-containing trimethoxysilane; for example, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, etc. (Meth) acryloyl group-containing silane coupling agents; vinyl group-containing silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane; 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane and the like And mercapto group-containing silane coupling agents; halogenated alkyl group-containing silane coupling agents such as 3-chloropropyltrimethoxysilane; and the like. Among these, epoxy group-containing silane coupling agents such as glycidoxypropyltrialkoxysilane (for example, 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane) are preferable.

As the silane coupling agent used in the technology disclosed herein, it is preferable to use a silane coupling agent having a functional group Y that reacts with the functional group y contained in the surface portion on the adhesive surface side of the adhesive layer. From the viewpoint of reactivity at normal temperature, a combination of a surface portion having a carboxy group as the functional group y and a silane coupling agent having an epoxy group as the functional group Y is particularly preferable. Other preferable combinations include amino group and epoxy group combination, hydroxyl group and epoxy group combination, carboxy group and amino group combination, isocyanate group and amino group combination, sulfo group and amino group combination , Etc. On the other hand, in some embodiments, the peeling force increasing agent supplying unit is a silane from the viewpoint of facilitating transfer of the peeling force increasing agent to the surface portion by maintaining the releasing force increasing agent in the supply unit in a free state. Does not have a functional group y (for example, a carboxy group) that reacts with a functional group Y (for example, an epoxy group) of the coupling agent, or the content [mol / g] of the functional group y is a concentration at the surface portion of the functional group y. It is preferably lower than [mol / g]. The content [mol / g] of the functional group y in the peeling force increasing agent supply part may be, for example, 1/10 or less, or 1/100 or less of the content [mol / g] of the functional group y in the surface part. However, it may be 1/1000 or less, or 1/10000 or less.

The molecular weight (Mw) of the silane coupling agent is not particularly limited, and can be, for example, about 120 to 1,000. Usually, a silane coupling agent having Mw of 180 or more, 200 or more, or 220 or more is usually used from the viewpoint of easy adjustment of the reworkable period and mobility from the supply unit to the adhesive surface through the surface unit. preferable. For the same reason, a silane coupling agent having Mw of 800 or less, 600 or less, 400 or less, or 300 or less is preferable. In some embodiments, a silane coupling agent having an Mw of 200 or more and 300 or less can be preferably used. As the value of Mw of the silane coupling agent, a value calculated based on the structural formula of the silane coupling agent is used. Alternatively, the manufacturer's nominal value may be used.

Other examples of materials that can be used as the peel strength increasing agent in the technology disclosed herein include a crosslinking agent. Crosslinking agents used as peeling force increasing agents are known in the field of pressure-sensitive adhesives, such as isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, carbodiimide-based crosslinking agents, melamine-based crosslinking agents, urea-based crosslinking agents. Among crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, hydrazine-based crosslinking agents, amine-based crosslinking agents, etc. Those can be appropriately selected and used. Examples of the crosslinking agent that can function as a peeling force increasing agent include an isocyanate-based crosslinking agent and an epoxy-based crosslinking agent as described later. It is preferable that the crosslinking agent used as the peeling force increasing agent is contained in the peeling force increasing agent supply section in a free form, that is, in a form in which the crosslinkable functional group is unreacted.

In the pressure-sensitive adhesive sheet disclosed herein, the amount of the peeling force increasing agent (for example, a silane coupling agent) contained in the peeling force increasing agent supply unit can be set so as to obtain a desired use effect, and is particularly limited. Not. The amount of the peeling force increasing agent may be, for example, 1 μg / cm ² or more, usually 5 μg / cm ² or more per 1 cm ² of the pressure-sensitive adhesive sheet area (typically corresponding to the area of the pressure-sensitive adhesive surface). It is appropriate that From the viewpoint of avoiding an excessively long period until the peeling force increases at room temperature, the amount of the peeling force increasing agent is preferably, for example, 10 μg / cm ² or more, and may be 25 μg / cm ² or more. It may be 35 μg / cm ² or more. In addition, depending on the use mode of the pressure-sensitive adhesive sheet, if the period until the peeling force increases at room temperature is too short, the period during which rework can be performed is shortened, so that inconveniences such as complicated process management may occur. From this point of view, in some embodiments, the amount of the release force increasing agent, for example, may be at 1000 [mu] g / cm ² or less, may be 500 [mu] g / cm ² or less, 200 [mu] g / cm ² or less, 100 [mu] g / cm ² or less, 70 [mu] g / cm ² or less or 55 [mu] g / cm ² or below.

The pressure-sensitive adhesive sheet disclosed herein has a pressure-sensitive adhesive increasing agent supply part at a location separated from the pressure-sensitive adhesive surface via the pressure-sensitive adhesive side surface part of the pressure-sensitive adhesive layer, and the peeling force increasing agent contained in the supply part Can be supplied to the surface portion. In the pressure-sensitive adhesive sheet comprising the A layer constituting the pressure-sensitive adhesive surface and the B layer disposed on the back side of the A layer, the B layer can be preferably used as a peeling force increasing agent supply unit. As a result, when the adhesive surface (surface of the A layer) is applied to the adherend, the peeling force increasing agent in the B layer is separated from the adherend via the A layer. Exhibits properties suitable for reworking (for example, the property that peeling force due to normal peeling or water peeling is not too high), while the peeling force increasing agent that has shifted from B layer to A layer with time is applied to the adherend and the A layer. The peeling force can be increased by acting between them.

The B layer is, for example, an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive (natural rubber-based, synthetic rubber-based, or a mixed system thereof), a silicone-based pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, or a polyether-based adhesive. The pressure-sensitive adhesive layer may include one or more pressure-sensitive adhesives selected from various known pressure-sensitive adhesives such as pressure-sensitive adhesives, polyamide-based pressure-sensitive adhesives, and fluorine-based pressure-sensitive adhesives. Here, the acrylic pressure-sensitive adhesive refers to a pressure-sensitive adhesive mainly composed of an acrylic polymer. The same applies to rubber-based adhesives and other adhesives. From the viewpoints of transparency, weather resistance, and the like, in some embodiments, an acrylic pressure-sensitive adhesive can be preferably employed as the constituent material of the B layer.

(Acrylic adhesive)
The acrylic pressure-sensitive adhesive constituting the B layer includes, for example, more than 50% by weight of (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 1 to 20 carbon atoms at the ester terminal. What contains the acrylic polymer comprised from the monomer component as a base polymer is preferable. Hereinafter, a (meth) acrylic acid alkyl ester having an alkyl group having X or more and Y or less carbon atoms at the ester end may be referred to as a “(meth) acrylic acid C _XY alkyl ester”. Since it is easy to balance the characteristics, the proportion of the (meth) acrylic acid C _1-20 alkyl ester in the whole monomer component may be, for example, 55% by weight or more, 60% by weight or more, and 70% by weight or more. But you can. For the same reason, the proportion of the (meth) acrylic acid C _1-20 alkyl ester in the monomer component may be, for example, 99.9% by weight or less, 99.5% by weight or less, or 99% by weight or less. Good.

Non-limiting specific examples of (meth) acrylic acid C _1-20 alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, ( N-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, (meth) Hexyl acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, (meth ) Decyl acrylate, isomethyl (meth) acrylate, undecyl (meth) acrylate, (meth ) Dodecyl acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, stearyl (meth) acrylate, (meth) Examples include isostearyl acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate, and the like.

Of these, at least (meth) acrylic acid C _4-20 alkyl ester is preferably used, and at least (meth) acrylic acid C _4-18 alkyl ester is more preferably used. For example, an acrylic pressure-sensitive adhesive containing one or both of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) as the monomer component is preferable, and an acrylic pressure-sensitive adhesive containing at least BA is particularly preferable. Other examples of (meth) acrylic acid C _4-20 alkyl esters that can be preferably used include isononyl acrylate, n-butyl methacrylate (BMA), 2-ethylhexyl methacrylate (2EHMA), isostearyl acrylate (iSTA) ) And the like.

In some embodiments, the monomer component that constitutes the base polymer of the B layer may include (meth) acrylic acid C _4-18 alkyl ester in a proportion of 40% by weight or more. The proportion of the (meth) acrylic acid C _4-18 alkyl ester in the monomer component may be, for example, 50% by weight or more, 60% by weight or more, or 65% by weight or more. It may be a monomer component containing (meth) acrylic acid C _6-18 alkyl ester at a ratio equal to or greater than any of the lower limit values described above.
From the viewpoint of enhancing the cohesiveness of the pressure-sensitive adhesive layer, the proportion of (meth) acrylic acid C _4-18 alkyl ester in the monomer component is usually suitably 99.5% by weight or less, and 95% by weight. % Or less, 85 wt% or less, or 75 wt% or less. It may be a monomer component containing (meth) acrylic acid C _6-18 alkyl ester at a ratio equal to or lower than any of the above upper limit values.

The monomer component constituting the base polymer of layer B includes (meth) acrylic acid alkyl ester and, if necessary, other monomer (copolymerizable monomer) copolymerizable with (meth) acrylic acid alkyl ester. May be. As the copolymerizable monomer, a monomer having a polar group (for example, a carboxy group, a hydroxyl group, a nitrogen atom-containing ring, etc.) or a monomer having a relatively high glass transition temperature (for example, 10 ° C. or higher) is preferably used. can do. A monomer having a polar group can be useful for introducing a crosslinking point into the acrylic polymer or increasing the cohesive strength of the pressure-sensitive adhesive. A copolymerizable monomer can be used individually by 1 type or in combination of 2 or more types.

Non-limiting specific examples of the copolymerizable monomer include the following.
Carboxy group-containing monomer: For example, acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid and the like.
Acid anhydride group-containing monomer: for example, maleic anhydride, itaconic anhydride.
Hydroxyl group-containing monomers: for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (meth) acryl 4-hydroxybutyl acid, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxy Hydroxyalkyl (meth) acrylates such as methylcyclohexyl) methyl (meth) acrylate and the like.
Monomers containing sulfonic acid groups or phosphoric acid groups: for example, styrene sulfonic acid, allyl sulfonic acid, sodium vinyl sulfonate, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfo Propyl (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid, 2-hydroxyethyl acryloyl phosphate and the like.
Epoxy group-containing monomers: For example, epoxy group-containing acrylates such as glycidyl (meth) acrylate and (meth) acrylic acid-2-ethylglycidyl ether, allyl glycidyl ether, (meth) acrylic acid glycidyl ether, and the like.
Cyano group-containing monomer: For example, acrylonitrile, methacrylonitrile and the like.
Isocyanate group-containing monomer: for example, 2-isocyanatoethyl (meth) acrylate.
Amide group-containing monomer: for example, (meth) acrylamide; N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropyl (meth) acrylamide, N, N-diisopropyl (meth) N, N-dialkyl (meth) acrylamide, such as acrylamide, N, N-di (n-butyl) (meth) acrylamide, N, N-di (t-butyl) (meth) acrylamide; N-ethyl (meth) N-alkyl (meth) acrylamides such as acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, Nn-butyl (meth) acrylamide; N-vinylcarboxylic amides such as N-vinylacetamide A monomer having a hydroxyl group and an amide group, for example, N- (2-hydro (Ciethyl) (meth) acrylamide, N- (2-hydroxypropyl) (meth) acrylamide, N- (1-hydroxypropyl) (meth) acrylamide, N- (3-hydroxypropyl) (meth) acrylamide, N- (2 N-hydroxyalkyl (meth) acrylamides such as -hydroxybutyl) (meth) acrylamide, N- (3-hydroxybutyl) (meth) acrylamide, N- (4-hydroxybutyl) (meth) acrylamide; alkoxy groups and amides Monomers having a group, for example, N-alkoxyalkyl (meth) acrylamides such as N-methoxymethyl (meth) acrylamide, N-methoxyethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide; N-dimethylaminopropi (Meth) acrylamide, N- (meth) acryloyl morpholine.
Amino group-containing monomer: for example, aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate.
Monomers having an epoxy group: for example, glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, allyl glycidyl ether.
Monomers having a nitrogen atom-containing ring: for example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N- Vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N- (meth) acryloyl-2-pyrrolidone, N- (meth) acryloylpiperidine, N- (meth) acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-3 -Morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisoxazole, N-vinyl Thiazole, N-vinylisothiazole, N-vinylpyridazine (E.g., lactams such as N- vinyl-2-caprolactam).
Monomers having a succinimide skeleton: for example, N- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, N- (meth) acryloyl-8-oxyhexamethylene succinimide, and the like.
Maleimides: For example, N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide and the like.
Itaconic imides: for example, N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexylitaconimide, N-cyclohexyl leuconconimide, N-lauryl Itacone imide and the like.
Aminoalkyl (meth) acrylates: for example, aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, (meth) acrylic acid t -Butylaminoethyl.
Alkoxy group-containing monomer: for example, 2-methoxyethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, (meth) acrylic acid (Meth) acrylic acid alkoxyalkylenes such as butoxyethyl and (meth) acrylic acid ethoxypropyl; (meth) acrylic acid alkoxyalkylene glycols such as (meth) acrylic acid methoxyethylene glycol and (meth) acrylic acid methoxypolypropylene glycol Kind.
Alkoxysilyl group-containing monomer: for example, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxy Alkoxysilyl group-containing (meth) acrylates such as propylmethyldiethoxysilane, and alkoxysilyl group-containing vinyl compounds such as vinyltrimethoxysilane and vinyltriethoxysilane.
Vinyl esters: For example, vinyl acetate, vinyl propionate and the like.
Vinyl ethers: For example, vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether.
Aromatic vinyl compounds: for example, styrene, α-methylstyrene, vinyltoluene and the like.
Olefin: For example, ethylene, butadiene, isoprene, isobutylene and the like.
(Meth) acrylic acid ester having an alicyclic hydrocarbon group: for example, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate, etc. An alicyclic hydrocarbon group-containing (meth) acrylate.
(Meth) acrylic acid ester having an aromatic hydrocarbon group: for example, an aromatic hydrocarbon group-containing (meth) acrylate such as phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate and the like.
In addition, heterocycle-containing (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate, halogen-containing (meth) acrylates such as vinyl chloride and fluorine-containing (meth) acrylate, silicon atoms such as silicone (meth) acrylate (Meth) acrylate, (meth) acrylic acid ester obtained from terpene compound derivative alcohol and the like.

When such a copolymerizable monomer is used, the amount used is not particularly limited, but it is usually appropriate to make it 0.01% by weight or more of the whole monomer component. From the viewpoint of more effectively using the copolymerizable monomer, the amount of the copolymerizable monomer used may be 0.1% by weight or more of the whole monomer component, or 0.5% by weight or more. Further, from the viewpoint of easily balancing the adhesive properties, the amount of the copolymerizable monomer used is usually suitably 50% by weight or less, preferably 40% by weight or less, based on the whole monomer component.

In some embodiments, the monomer component constituting the base polymer of the B layer may include a hydroxyl group-containing monomer. By using a hydroxyl group-containing monomer, the cohesive force of the pressure-sensitive adhesive and the degree of crosslinking (for example, crosslinking with an isocyanate crosslinking agent) can be suitably adjusted. The amount used in the case of using a hydroxyl group-containing monomer is not particularly limited, and may be, for example, 0.01% by weight or more of the whole monomer component, may be 0.1% by weight or more, may be 0.5% by weight or more, It may be 1% by weight or more, 5% by weight or more, or 10% by weight or more. Further, from the viewpoint of suppressing the water absorption of the B layer, in some embodiments, the amount of the hydroxyl group-containing monomer is suitably 40% by weight or less of the total monomer component, for example, 30% by weight or less. Alternatively, it may be 25% by weight or less, or 20% by weight or less.

In some embodiments, the monomer component constituting the base polymer of the B layer may include a monomer having a nitrogen atom-containing ring. Thereby, the cohesive force of an adhesive can be raised and the peeling force after time can be improved. As the monomer having a nitrogen atom-containing ring, those exemplified above can be used. For example, N-vinyl-2-pyrrolidone can be preferably used. The amount of the monomer having a nitrogen atom-containing ring is not particularly limited, and can be, for example, 1% by weight or more, 3% by weight or more, 5% by weight or more, or 7% by weight or more of the whole monomer component. Further, the amount of the monomer having a nitrogen atom-containing ring is suitably 40% by weight or less, for example, 30% by weight or less, 20% by weight or less, or 15% by weight based on the whole monomer component. It is good also as follows.

In some embodiments, the monomer component constituting the base polymer of the B layer can include an alicyclic hydrocarbon group-containing (meth) acrylate. Thereby, the cohesive force of an adhesive can be raised and the peeling force after time can be improved. As the alicyclic hydrocarbon group-containing (meth) acrylate, those exemplified above can be used. For example, cyclohexyl acrylate can be preferably used. The amount used in the case of using the alicyclic hydrocarbon group-containing (meth) acrylate is not particularly limited, and can be, for example, 1% by weight or more, 3% by weight or more, or 5% by weight or more of the whole monomer component. Further, the amount of the monomer having a nitrogen atom-containing ring is suitably 40% by weight or less, for example, 30% by weight or less, 20% by weight or less, or 15% by weight based on the whole monomer component. Or may be 10% by weight or less.

The composition of the monomer component constituting the base polymer of the B layer can be set such that the glass transition temperature Tg _B determined by the Fox formula based on the composition of the monomer component is −75 ° C. or higher and 10 ° C. or lower. In some embodiments, the Tg _B is suitably 0 ° C. or less, preferably −10 ° C. or less, preferably −20 ° C. or less, or −30 from the viewpoints of cohesion and impact resistance. It may be below ℃. In addition, Tg _B may be, for example, −60 ° C. or higher, or −50 ° C. or higher from the viewpoint of easily holding the peeling strength increasing agent in the B layer before the adhesive sheet is attached to the adherend. , −45 ° C. or higher, or −40 ° C. or higher.

Here, the Fox equation is a relational expression between the Tg of the copolymer and the glass transition temperature Tgi of the homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer, as shown below. .
1 / Tg = Σ (Wi / Tgi)
In the above Fox equation, Tg is the glass transition temperature (unit: K) of the copolymer, Wi is the weight fraction of monomer i in the copolymer (copolymerization ratio on a weight basis), and Tgi is the monomer i. Represents the glass transition temperature (unit: K) of the homopolymer.

As the glass transition temperature of the homopolymer used for the calculation of Tg, the values described in known materials are used. For example, for the monomers listed below, the following values are used as the glass transition temperature of the homopolymer of the monomer.
2-Ethylhexyl acrylate -70 ° C
n-Butyl acrylate -55 ° C
Isostearyl acrylate -18 ℃
Methyl methacrylate 105 ° C
Methyl acrylate 8 ℃
Cyclohexyl acrylate 15 ° C
N-Vinyl-2-pyrrolidone 54 ° C
2-Hydroxyethyl acrylate -15 ° C
4-hydroxybutyl acrylate -40 ° C
Dicyclopentanyl methacrylate 175 ° C
Acrylic acid 106 ℃
Methacrylic acid 228 ° C

For the glass transition temperature of homopolymers of monomers other than those exemplified above, the values described in “Polymer Handbook” (3rd edition, John Wiley & Sons, Inc., 1989) shall be used. When multiple types of values are described in this document, the highest value is adopted.

For monomers for which the glass transition temperature of the homopolymer is not described in the Polymer Handbook, the value obtained by the following measurement method is used (see Japanese Patent Application Publication No. 2007-51271). Specifically, a reactor equipped with a thermometer, a stirrer, a nitrogen introduction tube and a reflux condenser is charged with 100 parts by weight of monomer, 0.2 part by weight of azobisisobutyronitrile and 200 parts by weight of ethyl acetate as a polymerization solvent. Stir for 1 hour while flowing nitrogen gas. After removing oxygen in the polymerization system in this way, the temperature is raised to 63 ° C. and reacted for 10 hours. Next, the mixture is cooled to room temperature to obtain a homopolymer solution having a solid concentration of 33% by weight. Next, this homopolymer solution is cast-coated on a release liner and dried to prepare a test sample (sheet-like homopolymer) having a thickness of about 2 mm. This test sample was punched into a disk shape having a diameter of 7.9 mm, sandwiched between parallel plates, and subjected to shear strain at a frequency of 1 Hz using a viscoelasticity tester (ARES, manufactured by Rheometrics), in a temperature range of −70 to 150 ° C. The viscoelasticity is measured by the shear mode at a heating rate of 5 ° C./min, and the peak top temperature of tan δ is defined as Tg of the homopolymer.

The layer B contains the monomer component having the composition as described above in the form of a polymer, an unpolymer (that is, a form in which the polymerizable functional group is unreacted), or a mixture thereof, and further includes a peeling force increasing agent. It can be formed using a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition includes a water-dispersed pressure-sensitive adhesive composition in which a pressure-sensitive adhesive (pressure-sensitive adhesive component) is dispersed in water, a solvent-type pressure-sensitive adhesive composition in a form containing a pressure-sensitive adhesive in an organic solvent, ultraviolet light, radiation, and the like. Active energy ray-curable pressure-sensitive adhesive composition prepared to be cured by active energy rays to form a pressure-sensitive adhesive, a hot-melt type pressure-sensitive adhesive that is applied in a heated and melted state and forms a pressure-sensitive adhesive when cooled to near room temperature It can be in various forms such as a composition.

In the polymerization, a known or commonly used thermal polymerization initiator or photopolymerization initiator can be used depending on the polymerization method, polymerization mode, and the like. Such a polymerization initiator can be used individually by 1 type or in combination of 2 or more types as appropriate.

The thermal polymerization initiator is not particularly limited. For example, an azo polymerization initiator, a peroxide initiator, a redox initiator by a combination of a peroxide and a reducing agent, a substituted ethane initiator. Etc. can be used. More specifically, for example, 2,2′-azobisisobutyronitrile (AIBN), 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis (2-amidinopropane) ) Dihydrochloride, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis (N, N′-dimethyleneisobutylamidine), 2 Azo initiators such as 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate; persulfates such as potassium persulfate and ammonium persulfate; benzoyl peroxide, t-butyl Peroxide initiators such as hydroperoxide and hydrogen peroxide; for example, substituted ethane initiators such as phenyl substituted ethane; Combination of salt and sodium bisulfite, redox initiators such as a combination of a peroxide and sodium ascorbate; but the like, without limitation. The thermal polymerization can be preferably carried out at a temperature of about 20 to 100 ° C. (typically 40 to 80 ° C.), for example.

The photopolymerization initiator is not particularly limited. For example, ketal photopolymerization initiator, acetophenone photopolymerization initiator, benzoin ether photopolymerization initiator, acylphosphine oxide photopolymerization initiator, α- Ketol photopolymerization initiator, aromatic sulfonyl chloride photopolymerization initiator, photoactive oxime photopolymerization initiator, benzoin photopolymerization initiator, benzyl photopolymerization initiator, benzophenone photopolymerization initiator, thioxanthone light A polymerization initiator or the like can be used.

The amount of such thermal polymerization initiator or photopolymerization initiator used is not particularly limited and can be a normal amount used depending on the polymerization method, polymerization mode, and the like. For example, about 0.001 to 5 parts by weight of a polymerization initiator (typically about 0.01 to 2 parts by weight, for example, about 0.01 to 1 part by weight) is used with respect to 100 parts by weight of the monomer to be polymerized. Can do.

For the above polymerization, conventionally known various chain transfer agents (which can also be grasped as molecular weight regulators or polymerization degree regulators) can be used as necessary. As the chain transfer agent, mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan, thioglycolic acid and α-thioglycerol can be used. Or you may use the chain transfer agent (non-sulfur type chain transfer agent) which does not contain a sulfur atom. Specific examples of the non-sulfur chain transfer agent include anilines such as N, N-dimethylaniline and N, N-diethylaniline; terpenoids such as α-pinene and terpinolene; α-methylstyrene, α-methylstyrene dimer Styrenes such as dibenzylideneacetone, cinnamyl alcohol, cinnamylaldehyde and other benzylidenyl groups; hydroquinones such as hydroquinone and naphthohydroquinone; quinones such as benzoquinone and naphthoquinone; 2,3-dimethyl-2-butene Olefins such as 1,5-cyclooctadiene; alcohols such as phenol, benzyl alcohol and allyl alcohol; benzyl hydrogens such as diphenylbenzene and triphenylbenzene;
A chain transfer agent can be used individually by 1 type or in combination of 2 or more types. When a chain transfer agent is used, the amount used can be, for example, about 0.01 to 1 part by weight with respect to 100 parts by weight of the monomer component. The technique disclosed here can be preferably implemented even in an embodiment in which no chain transfer agent is used.

The pressure-sensitive adhesive sheet according to some embodiments may have a B layer (peeling force increasing agent supply unit) formed from an active energy ray-curable pressure-sensitive adhesive composition containing a peeling force increasing agent. In the present specification, the “active energy ray” refers to an energy ray having an energy that can cause a chemical reaction such as a polymerization reaction, a crosslinking reaction, and decomposition of an initiator. Examples of active energy rays here include light such as ultraviolet rays, visible rays, and infrared rays, and radiation such as α rays, β rays, γ rays, electron beams, neutron rays, and X rays. A preferred example of the active energy ray-curable pressure-sensitive adhesive composition is a photocurable pressure-sensitive adhesive composition. The photocurable pressure-sensitive adhesive composition has an advantage that even a thick pressure-sensitive adhesive layer can be easily formed. Among these, an ultraviolet curable pressure-sensitive adhesive composition is preferable.

The photocurable pressure-sensitive adhesive composition typically has at least a part of the monomer components of the composition (may be part of the monomer type or part of the quantity). In the form of a polymer. The polymerization method for forming the polymer is not particularly limited, and various conventionally known polymerization methods can be appropriately employed. For example, thermal polymerization such as solution polymerization, emulsion polymerization and bulk polymerization (typically performed in the presence of a thermal polymerization initiator); photopolymerization performed by irradiating light such as ultraviolet rays (typically It is carried out in the presence of a photopolymerization initiator.); Radiation polymerization carried out by irradiation with radiation such as β rays, γ rays, etc. Of these, photopolymerization is preferred.

The photocurable pressure-sensitive adhesive composition according to a preferred embodiment includes a partially polymerized monomer component. Such a partial polymer is typically a mixture of a polymer derived from a monomer component and an unreacted monomer, and preferably exhibits a syrup shape (viscous liquid). Hereinafter, such a partially polymerized product may be referred to as “monomer syrup” or simply “syrup”. The polymerization method for partial polymerization of the monomer component is not particularly limited, and various polymerization methods as described above can be appropriately selected and used. From the viewpoint of efficiency and simplicity, a photopolymerization method can be preferably employed. According to the photopolymerization, the polymerization conversion rate (monomer conversion) of the monomer component can be easily controlled by the polymerization conditions such as the light irradiation amount (light quantity).

The polymerization conversion rate of the monomer mixture in the partial polymer is not particularly limited. The polymerization conversion rate can be, for example, about 70% by weight or less, and preferably about 60% by weight or less. From the viewpoint of ease of preparation of the pressure-sensitive adhesive composition containing the above partial polymer, coating properties, etc., the polymerization conversion rate is usually suitably about 50% by weight or less, and about 40% by weight or less (for example, about 35%). % By weight or less) is preferred. The lower limit of the polymerization conversion rate is not particularly limited, but is typically about 1% by weight or more, and usually about 5% by weight or more is appropriate.

The pressure-sensitive adhesive composition containing a partially polymerized monomer component is obtained by, for example, partially polymerizing a monomer mixture containing the entire amount of monomer components used for preparing the pressure-sensitive adhesive composition by an appropriate polymerization method (for example, photopolymerization method). Can be obtained. Further, the pressure-sensitive adhesive composition containing the partial polymerization product of the monomer component includes a partial polymerization product or a complete polymerization product of the monomer mixture including a part of the monomer components used in the preparation of the pressure-sensitive adhesive composition, and the remaining monomer. It may be a mixture with a component or a partial polymer thereof. In the present specification, the “completely polymerized product” means that the polymerization conversion rate is more than 95% by weight.

In the pressure-sensitive adhesive composition containing the partial polymer, in addition to the peel strength increasing agent, other components used as necessary (for example, a photopolymerization initiator, a crosslinking agent as described later, a polyfunctional monomer, an acrylic System oligomers, tackifying resins, and the like). The method of blending such other components is not particularly limited, and for example, it may be previously contained in the monomer mixture or added to the partial polymer.

The pressure-sensitive adhesive sheet according to some embodiments may have a layer B (peeling force increasing agent supply unit) formed from a solvent-type pressure-sensitive adhesive composition containing a peeling force increasing agent. The solvent-type pressure-sensitive adhesive composition typically contains a solution polymer of monomer components, a peel strength increasing agent, and an additive used as necessary. The solvent (polymerization solvent) used for the solution polymerization can be appropriately selected from conventionally known organic solvents. For example, aromatic compounds such as toluene (typically aromatic hydrocarbons); esters such as ethyl acetate and butyl acetate; aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane; Halogenated alkanes such as dichloroethane; lower alcohols such as isopropyl alcohol (for example, monohydric alcohols having 1 to 4 carbon atoms); ethers such as tert-butyl methyl ether; ketones such as methyl ethyl ketone; Any one kind of solvent or a mixed solvent of two or more kinds can be used. According to solution polymerization, a polymerization reaction liquid in a form in which a polymer of monomer components is dissolved in a polymerization solvent is obtained. The solvent-type pressure-sensitive adhesive composition used for forming the B layer can be preferably produced using the polymerization reaction solution.

In the solvent-type pressure-sensitive adhesive composition, in addition to the peel strength increasing agent, other components used as necessary (for example, a photopolymerization initiator, a crosslinking agent as described later, a polyfunctional monomer, an acrylic oligomer, Tackifying resins and the like) may be blended. The solvent-type pressure-sensitive adhesive composition may be provided with photocurability (photocrosslinking property), for example, by adding a polyfunctional monomer and a photopolymerization initiator to the polymerization reaction solution.

The content of the peeling strength increasing agent (for example, silane coupling agent) in the B layer can be, for example, 0.005 part by weight or more per 100 parts by weight of the base polymer of the B layer. The content of the peeling strength increasing agent per 100 parts by weight of the base polymer is usually suitably 0.05 parts by weight or more, and is 0.10 parts by weight, 0.20 parts by weight or 0.30 parts by weight. It may be more than one part. By increasing the content of the peeling force increasing agent, the peeling force increasing agent in the B layer is efficiently transferred to the A layer using the concentration gradient, and further efficiently reaches the interface between the A layer and the adherend. It is possible to exert the effect of increasing the peeling force. In addition, depending on the use mode of the pressure-sensitive adhesive sheet, if the period until the peeling force increases with time at room temperature is too short, there may be inconveniences such as the reworkable period becomes too short and the process management becomes complicated. obtain. From this point of view, in some embodiments, the content of the peel strength increasing agent per 100 parts by weight of the base polymer in the B layer may be, for example, 5 parts by weight or less, 3 parts by weight or less, and 1 part by weight or less. It may be 0.7 parts by weight or less.

(Crosslinking agent)
In the B layer, apart from the peeling force increasing agent formulated with the intention of improving the peeling force of the adhesive sheet to the adherend by being supplied from the B layer to the A layer after being attached to the adherend. In addition, a crosslinking agent can be contained as necessary mainly for the purpose of crosslinking in the B layer or crosslinking between the B layer and its adjacent surface. Such a cross-linking agent typically has a bond or interaction with a component of the B layer, a bond between the cross-linking agents, or a combination of the bond and another B layer at least at the time of application to an adherend. The cross-linking agent is used in a state in which the transfer (supply) of the cross-linking agent from the B layer to the A layer is hindered (ie, a non-free state in the B layer) due to interaction with the components.

The type of the crosslinking agent is not particularly limited, and can be selected from conventionally known crosslinking agents so that the crosslinking agent exhibits an appropriate crosslinking function in the B layer, for example, according to the composition of the B layer. . As a crosslinking agent that can be an option depending on the composition of the B layer, an isocyanate crosslinking agent, an epoxy crosslinking agent, an oxazoline crosslinking agent, an aziridine crosslinking agent, a carbodiimide crosslinking agent, a melamine crosslinking agent, a urea crosslinking agent, Examples thereof include metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, hydrazine crosslinking agents, and amine crosslinking agents. These can be used alone or in combination of two or more.

As the isocyanate-based crosslinking agent, a bifunctional or higher polyfunctional isocyanate compound can be used. For example, aromatic isocyanates such as tolylene diisocyanate, xylene diisocyanate, polymethylene polyphenyl diisocyanate, tris (p-isocyanatophenyl) thiophosphate, diphenylmethane diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; aliphatics such as hexamethylene diisocyanate Isocyanate; and the like. Commercially available products include trimethylolpropane / tolylene diisocyanate trimer adduct (trade name “Coronate L” manufactured by Tosoh Corporation), trimethylolpropane / hexamethylene diisocyanate trimer adduct (trade name “manufactured by Tosoh Corporation, trade name“ Coronate HL "), isocyanurate of hexamethylene diisocyanate (manufactured by Tosoh Corporation, trade name" Coronate HX "), and the like. In the water-dispersed pressure-sensitive adhesive composition, it is preferable to use an isocyanate crosslinking agent that can be dissolved or dispersed in water. For example, a water-soluble, water-dispersible or self-emulsifying type isocyanate crosslinking agent can be preferably employed. A so-called blocked isocyanate type isocyanate-based crosslinking agent in which an isocyanate group is blocked can be preferably used.

As the epoxy-based crosslinking agent, those having two or more epoxy groups in one molecule can be used without particular limitation. Epoxy crosslinking agents having 3 to 5 epoxy groups in one molecule are preferred. Specific examples of the epoxy crosslinking agent include N, N, N ′, N′-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, 1,6-hexane. Examples include diol diglycidyl ether, polyethylene glycol diglycidyl ether, and polyglycerol polyglycidyl ether. Commercially available epoxy-based crosslinking agents include trade names “TETRAD-X” and “TETRAD-C” manufactured by Mitsubishi Gas Chemical Company, “Epicron CR-5L” manufactured by DIC, and products manufactured by Nagase ChemteX Corporation. Examples include the name “Denacol EX-512” and the trade name “TEPIC-G” manufactured by Nissan Chemical Industries, Ltd. In the water-dispersed pressure-sensitive adhesive composition, it is preferable to use an epoxy-based crosslinking agent that can be dissolved or dispersed in water.

As the oxazoline-based crosslinking agent, one having one or more oxazoline groups in one molecule can be used without any particular limitation. In the water-dispersed pressure-sensitive adhesive composition, it is preferable to use an oxazoline-based crosslinking agent that can be dissolved or dispersed in water.
Examples of the aziridine-based crosslinking agent include trimethylolpropane tris [3- (1-aziridinyl) propionate], trimethylolpropane tris [3- (1- (2-methyl) aziridinylpropionate)] and the like. It is done.
As the carbodiimide-based crosslinking agent, a low molecular compound or a high molecular compound having two or more carbodiimide groups can be used. In the water-dispersed pressure-sensitive adhesive composition, it is preferable to use a carbodiimide-based crosslinking agent that can be dissolved or dispersed in water.

In some embodiments, a peroxide may be used as a crosslinking agent. Peroxides include di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxyneodecanoate , T-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxyisobutyrate, di Examples thereof include benzoyl peroxide. Among these, as the peroxide having particularly excellent crosslinking reaction efficiency, di (4-t-butylcyclohexyl) peroxydicarbonate, dilauroyl peroxide, dibenzoyl peroxide, and the like can be given. In addition, when a peroxide is used as the polymerization initiator, it is possible to use the remaining peroxide for the crosslinking reaction without being used for the polymerization reaction. In that case, the remaining amount of peroxide is quantified, and when the proportion of peroxide is less than a predetermined amount, it is preferable to add the peroxide so that it becomes a predetermined amount as necessary. The peroxide can be quantified by the method described in Japanese Patent No. 4971517.

The content of the crosslinking agent (when two or more crosslinking agents are included, the total amount thereof) is not particularly limited. From the viewpoint of realizing a pressure-sensitive adhesive that exhibits a good balance of adhesive properties such as adhesive strength and cohesive strength, the content of the crosslinking agent is usually about 5 weights per 100 parts by weight of the monomer component contained in the pressure-sensitive adhesive composition. The amount is suitably 0.001 to 5 parts by weight, more preferably about 0.001 to 4 parts by weight, and more preferably about 0.001 to 3 parts by weight. Is more preferable. Or the adhesive composition which does not contain the above crosslinking agents may be sufficient.

In order to advance the crosslinking reaction more effectively, a crosslinking catalyst may be used. Examples of the cross-linking catalyst include metal-based cross-linking catalysts such as tetra-n-butyl titanate, tetraisopropyl titanate, nurse ferric iron, butyl tin oxide, and dioctyl tin dilaurate. Of these, tin-based crosslinking catalysts such as dioctyltin dilaurate are preferred. The amount of the crosslinking catalyst used is not particularly limited. The amount of the crosslinking catalyst used relative to 100 parts by weight of the base polymer of layer B may be, for example, from about 0.0001 part by weight to 1 part by weight, or from 0.001 part by weight to 0.1 part by weight. 005 weight or more and 0.5 weight part or less may be sufficient.

The pressure-sensitive adhesive composition can contain a compound that causes keto-enol tautomerism as a crosslinking retarder. For example, in a pressure-sensitive adhesive composition containing an isocyanate-based cross-linking agent or a pressure-sensitive adhesive composition that can be used by blending an isocyanate-based cross-linking agent, an embodiment including a compound that causes keto-enol tautomerism can be preferably employed. Thereby, the effect which extends the pot life of an adhesive composition may be implement | achieved.
Various β-dicarbonyl compounds can be used as the compound that causes keto-enol tautomerism. Specific examples include β-diketones such as acetylacetone and 2,4-hexanedione; acetoacetates such as methyl acetoacetate and ethyl acetoacetate; propionylacetates such as ethyl propionylacetate; isobutyryl such as ethyl isobutyrylacetate Acetic acid esters; Malonic acid esters such as methyl malonate and ethyl malonate; Among these, acetylacetone and acetoacetic acid esters are preferable compounds. Compounds that produce keto-enol tautomerism can be used singly or in combination of two or more.
The content of the compound that causes keto-enol tautomerism may be, for example, 0.1 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the monomer component used for preparing the pressure-sensitive adhesive composition. The amount is suitably 0.5 parts by weight or more and 15 parts by weight or less, for example, 1 part by weight or more and 10 parts by weight or less, and may be 1 part by weight or more and 5 parts by weight or less.

A polyfunctional monomer may be used for the pressure-sensitive adhesive layer as necessary. The polyfunctional monomer can be used for the purpose of adjusting the cohesive force by being used in place of the crosslinking agent as described above or in combination with the crosslinking agent. For example, in a pressure-sensitive adhesive layer formed from a photocurable pressure-sensitive adhesive composition, a polyfunctional monomer can be preferably used.
Examples of the multifunctional monomer include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, Pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,12-dodecane Diol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol methane tri (meth) acrylate, allyl (meth) acrylate, vinyl Le (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl diol (meth) acrylate, hexyl di (meth) acrylate. Of these, trimethylolpropane tri (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and dipentaerythritol hexa (meth) acrylate can be preferably used. A polyfunctional monomer can be used individually by 1 type or in combination of 2 or more types.

The amount of the polyfunctional monomer used varies depending on the molecular weight, the number of functional groups, etc., but is usually in the range of about 0.01 to 3.0 parts by weight with respect to 100 parts by weight of the base polymer of the B layer. Is appropriate. In some embodiments, the amount of the polyfunctional monomer used relative to 100 parts by weight of the base polymer may be, for example, 0.02 parts by weight or more, 0.1 parts by weight or more, 0.5 parts by weight As mentioned above, it may be 1.0 parts by weight or more or 2.0 parts by weight or more. Higher cohesion tends to be obtained by increasing the amount of the polyfunctional monomer used. On the other hand, from the viewpoint of avoiding a decrease in the adhesion between the layer B and the adjacent layer due to excessive cohesion, the amount of the polyfunctional monomer used relative to 100 parts by weight of the base polymer is, for example, 10 parts by weight or less. It may be 5.0 parts by weight or less, or 3.0 parts by weight or less. That the usage-amount of a polyfunctional monomer is not too much may be advantageous also from a viewpoint of the transferability improvement to the A layer of the peeling force increasing agent contained in the B layer.

(Acrylic oligomer)
The pressure-sensitive adhesive composition used for forming the B layer (and hence the B layer formed from the composition) has an improved cohesive force and a surface adjacent to the B layer (for example, the back surface of the A layer, the support An acrylic oligomer can be contained from the viewpoint of improving adhesiveness to the surface or the like. As the acrylic oligomer, it is preferable to use a polymer having a Tg higher than that of the copolymer (that is, the base polymer) corresponding to the composition of the monomer component.

The Tg of the acrylic oligomer is not particularly limited, and may be, for example, about 20 ° C. or higher and 300 ° C. or lower. The Tg may be, for example, about 30 ° C. or higher, about 40 ° C. or higher, about 60 ° C. or higher, about 80 ° C. or higher, or about 100 ° C. or higher. As the Tg of the acrylic oligomer increases, the effect of improving the cohesive force generally tends to increase. Further, from the viewpoint of anchoring property to the support, impact absorption, etc., the Tg of the acrylic oligomer may be, for example, about 250 ° C. or less, and may be about 200 ° C. or less, about 180 ° C. or less, or about 150 ° C. or less. Good. The Tg of the acrylic oligomer is a value calculated on the basis of the Fox equation, similarly to the Tg of the copolymer corresponding to the composition of the monomer component.

The weight average molecular weight (Mw) of the acrylic oligomer is typically about 1000 or more and less than about 30000, preferably about 1500 or more and less than about 10,000, and more preferably about 2000 or more and less than about 5000. When Mw is within the above range, the effect of improving the cohesiveness and the adhesion with the adjacent surface is easily exhibited. Mw of the acrylic oligomer can be measured by gel permeation chromatography (GPC) and obtained as a standard polystyrene equivalent value. Specifically, it is measured on a HPLC 8020 manufactured by Tosoh Corporation using two TSKgelGMH-H (20) columns as a column and a tetrahydrofuran solvent at a flow rate of about 0.5 ml / min.

The monomer component constituting the acrylic oligomer includes the above-mentioned various (meth) acrylic acid C _1-20 alkyl esters; the above-mentioned various alicyclic hydrocarbon group-containing (meth) acrylates; the above-mentioned various aromatic carbonizations. (Meth) acrylate monomers such as hydrogen group-containing (meth) acrylates; (meth) acrylates obtained from terpene compound derivative alcohols. These can be used alone or in combination of two or more.

Acrylic oligomers are alkyl (meth) acrylates in which alkyl groups have a branched structure, such as isobutyl (meth) acrylate and t-butyl (meth) acrylate; alicyclic hydrocarbon group-containing (meth) acrylates and aromatic hydrocarbons It is preferable from the viewpoint of improving adhesiveness that an acrylic monomer having a relatively bulky structure typified by a group-containing (meth) acrylate; In addition, when ultraviolet rays are employed in the synthesis of acrylic oligomers or in the production of the pressure-sensitive adhesive layer, monomers having a saturated hydrocarbon group at the ester end are preferred from the viewpoint that polymerization inhibition is difficult to occur. An alkyl (meth) acrylate having a branched structure or a saturated alicyclic hydrocarbon group-containing (meth) acrylate can be suitably used.

The proportion of the (meth) acrylate monomer in the total monomer components constituting the acrylic oligomer is typically more than 50% by weight, preferably 60% by weight or more, more preferably 70% by weight or more (for example, 80% by weight). Or more and 90% by weight or more). In a preferred embodiment, the acrylic oligomer has a monomer composition substantially consisting of only one or two or more (meth) acrylate monomers. When the monomer component contains an alicyclic hydrocarbon group-containing (meth) acrylate and (meth) acrylic acid C _1-20 alkyl ester, the weight ratio thereof is not particularly limited, and is, for example, 10/90 to 90/10 Range, 20/80 to 80/20, 70/30 to 30/70, and the like.

As a constituent monomer component of the acrylic oligomer, a functional group-containing monomer can be used as necessary in addition to the (meth) acrylate monomer. Examples of functional group-containing monomers include monomers having a nitrogen atom-containing heterocycle such as N-vinyl-2-pyrrolidone and N-acryloylmorpholine; amino group-containing monomers such as N, N-dimethylaminoethyl (meth) acrylate; Amide group-containing monomers such as N-diethyl (meth) acrylamide; Carboxy group-containing monomers such as AA and MAA; Hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate. These functional group-containing monomers can be used alone or in combination of two or more. When the functional group-containing monomer is used, the ratio of the functional group-containing monomer in the total monomer components constituting the acrylic oligomer can be, for example, 1% by weight or more, 2% by weight or more, or 3% by weight or more. For example, it may be 15% by weight or less, 10% by weight or less, or 7% by weight or less.

Suitable acrylic oligomers include, for example, dicyclopentanyl methacrylate (DCPMA), cyclohexyl methacrylate (CHMA), isobornyl methacrylate (IBXMA), isobornyl acrylate (IBXA), dicyclopentanyl acrylate (DCPA), In addition to homopolymers of 1-adamantyl methacrylate (ADMA) and 1-adamantyl acrylate (ADA), a copolymer of DCPMA and MMA, a copolymer of DCPMA and IBXMA, and a copolymer of ADA and methyl methacrylate (MMA) Copolymer, copolymer of CHMA and isobutyl methacrylate (IBMA), copolymer of CHMA and IBXMA, copolymer of CHMA and acryloylmorpholine (ACMO), CHMA and diethylacrylamide ( Copolymers of EAA), a copolymer of CHMA and AA, and the like.

The acrylic oligomer can be formed by polymerizing its constituent monomer components. The polymerization method and the polymerization mode are not particularly limited, and various conventionally known polymerization methods (for example, solution polymerization, emulsion polymerization, bulk polymerization, photopolymerization, radiation polymerization, etc.) can be employed in an appropriate mode. The types of polymerization initiators (for example, azo polymerization initiators) that can be used as necessary are substantially the same as those exemplified for the synthesis of an acrylic polymer as a base polymer. Since the amount of the chain transfer agent (for example, mercaptans) is appropriately set based on common general technical knowledge so as to obtain a desired molecular weight, detailed description thereof is omitted.

When the acrylic oligomer is contained in the adhesive constituting the B layer, the content thereof can be, for example, 0.01 parts by weight or more with respect to 100 parts by weight of the acrylic polymer (base polymer). From the viewpoint of obtaining a higher effect, it may be 0.05 parts by weight or more, or 0.1 parts by weight or more, or 0.2 parts by weight or more. From the viewpoint of compatibility with the acrylic polymer, the content of the acrylic oligomer is usually suitably less than 50 parts by weight, preferably less than 30 parts by weight, more preferably 25 parts by weight. Or less, 10 parts by weight or less, 5 parts by weight or less, or 1 part by weight or less.

<Surface part>
The peeling force increasing agent supply unit described above is separated from the adhesive surface via the surface portion of the adhesive layer. For example, in a mode in which the B layer is laminated on the back surface of the A layer and the B layer is a peeling force increasing agent supplying unit, the peeling force increasing agent supplying unit is separated from the adhesive surface by the A layer. From the viewpoint of improving the cohesiveness of the pressure-sensitive adhesive layer and improving the non-glue residue, the B layer is preferably disposed in direct contact with the back surface of the A layer.

The A layer is, for example, known acrylic adhesive, rubber adhesive, silicone adhesive, polyester adhesive, urethane adhesive, polyether adhesive, polyamide adhesive, fluorine adhesive, etc. The pressure-sensitive adhesive layer may include one or more pressure-sensitive adhesives selected from the various pressure-sensitive adhesives. In some embodiments, an acrylic pressure-sensitive adhesive can be preferably employed as the constituent material of the A layer. The pressure-sensitive adhesive sheet disclosed herein includes a pressure-sensitive adhesive layer including an A layer and a B layer, and the A layer and the B layer can be preferably implemented in an embodiment in which both are acrylic pressure-sensitive adhesive layers. The acrylic pressure-sensitive adhesive constituting the A layer can be selected, for example, from those exemplified as the acrylic pressure-sensitive adhesive that can be used for the B layer so that desired characteristics are exhibited in combination with the B layer. . The A layer may have a single layer structure composed of one layer, or may have a multilayer structure including two or more layers having different compositions. From the viewpoint of ease of production of the pressure-sensitive adhesive sheet, a configuration in which the A layer has a single layer structure can be preferably employed.

In some embodiments, the monomer component constituting the base polymer (for example, acrylic polymer) of the A layer contains (meth) acrylic acid C _4-18 alkyl ester in a proportion of 50% by weight or more of the total monomer component. May be included. The proportion of the (meth) acrylic acid C _4-18 alkyl ester in the monomer component may be, for example, 60% by weight or more, 70% by weight or more, 75% by weight or more, or 80% by weight or more. It may be a monomer component containing (meth) acrylic acid C _6-18 alkyl ester at a ratio equal to or greater than any of the lower limit values described above. According to the A layer having such a composition, good reworkability is easily obtained at the initial stage of application to the adherend (for example, at least about 1 to 3 days, preferably about 1 to 7 days after application). .
In addition, from the viewpoint of effectively exhibiting the action of the peeling force increasing agent transferred from the peeling force increasing agent supply section to the A layer, the proportion of the (meth) acrylic acid C _4-18 alkyl ester in the monomer component is usually It is appropriate that the amount is 99.5% by weight or less, which may be 99% by weight or less, 98% by weight or less, 97% by weight or less, or 95% by weight or less. It may be a monomer component containing (meth) acrylic acid C _6-18 alkyl ester at a ratio equal to or lower than any of the above upper limit values.

The monomer component constituting the base polymer of the A layer can contain a copolymerizable monomer together with the (meth) acrylic acid alkyl ester. The copolymerizable monomer can be appropriately selected from those exemplified as the copolymerizable monomer that can be used for the base polymer of the B layer. By using the copolymerizable monomer, the action of the peeling strength increasing agent supplied from the B layer to the A layer can be more effectively exhibited. The amount of the copolymerizable monomer used is suitably 0.01% by weight or more, for example, 0.1% by weight or more, and 0.5% by weight or more based on the total amount of the monomer components constituting the A layer. 1.0% by weight or more, or 2.0% by weight or more. Further, from the viewpoint of easily balancing the adhesive properties, the amount of the copolymerizable monomer used is usually suitably 50% by weight or less of the total monomer component, preferably 40% by weight or less, It may be 20% by weight or less, 10% by weight or less, or 5% by weight or less.

In the aspect in which the peeling force increasing agent contained in the B layer (peeling force increasing agent supply unit) has the functional group X and the functional group Y, the A layer preferably has the functional group y that reacts with the functional group Y. . The functional group X is preferably a group that reacts with a hydroxyl group that may be present on the surface of the adherend or a precursor thereof. According to the pressure-sensitive adhesive sheet having such a configuration, after the pressure-sensitive adhesive surface (the surface of the layer A) is attached to the adherend, the release force increasing agent capable of reacting with the surface of the adherend and the functional group y of the layer A respectively By being supplied from the B layer to the A layer, the peeling force of the pressure-sensitive adhesive sheet from the adherend can be effectively improved. The functional group y is preferably contained in the base polymer of the A layer. For example, the functional group y can be introduced into the base polymer of the A layer by using a copolymerizable monomer having the functional group y. When an epoxy group-containing silane coupling agent is used as the peeling force increasing agent, a carboxy group or an amino group can be adopted as the functional group y of the A layer. More preferably, the functional group y is a carboxy group.

In an embodiment in which the monomer component constituting the base polymer of the A layer contains a carboxy group-containing monomer, suitable examples of the carboxy group-containing monomer include acrylic acid (AA) and methacrylic acid (MAA). AA and MAA may be used in combination. When AA and MAA are used in combination, their weight ratio (AA / MAA) is not particularly limited, and can be, for example, in the range of about 0.1 to 10. In some embodiments, the weight ratio (AA / MAA) may be, for example, approximately 0.3 or more, and may be approximately 0.5 or more. The weight ratio (AA / MAA) may be about 4 or less, for example, or about 3 or less.

By using a carboxy group-containing monomer as a monomer component constituting the base polymer of the A layer, an aqueous liquid such as water can be quickly adapted to the surface of the A layer. This can be useful for reducing the water peeling force FWi, FW1 at the initial stage of pasting or one day after the pasting. The amount of the carboxy group-containing monomer used may be, for example, 0.05% by weight or more of the whole monomer component, 0.1% by weight or more, 0.3% by weight or more, 0.5% by weight or more. However, it may be 0.8% by weight or more. The proportion of the carboxy group-containing monomer may be, for example, 15% by weight or less, 10% by weight or less, 5% by weight or less, 4.5% by weight or less, or 3.5% by weight or less. Alternatively, it may be 3.0% by weight or less. It is preferable that the amount of the carboxy group-containing monomer used is not too large from the viewpoint of improving the bonding reliability by increasing the water peeling force over time. In addition, the fact that the amount of the carboxy group-containing monomer used is not too large is also advantageous from the viewpoint of preventing an event where water used when the adhesive sheet is peeled off by water is absorbed by the A layer and water is insufficient during the peeling. obtain.

In some embodiments, the monomer component constituting the base polymer of the A layer may include an alkoxysilyl group-containing monomer. The alkoxysilyl group-containing monomer is typically an ethylenically unsaturated monomer having at least one (preferably two or more, for example, two or three) alkoxysilyl group in one molecule. By polymerizing a monomer component containing an alkoxysilyl group-containing monomer, a base polymer having an alkoxysilyl group or a silanol group obtained by hydrolysis thereof in the side chain is obtained. By using this side chain, a crosslinked structure by a condensation reaction of silanol groups (silanol condensation) can be formed. As the alkoxysilyl group-containing monomer, the aforementioned alkoxysilyl group-containing (meth) acrylate, alkoxysilyl group-containing vinyl compound, or the like can be used. These can be used alone or in combination of two or more. Of these, alkoxysilyl group-containing (meth) acrylates such as 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane are preferable.

In the embodiment in which the monomer component constituting the base polymer of the A layer contains an alkoxysilyl group-containing monomer, the proportion of the alkoxysilyl group-containing monomer in the entire monomer component can be, for example, 0.005% by weight or more, Is suitably 0.01% by weight or more. In addition, from the viewpoint of avoiding a decrease in peeling force due to excessive crosslinking, the proportion of the alkoxysilyl group-containing monomer is usually suitably 0.5% by weight or less, and may be 0.1% by weight or less, It may be 0.05% by weight or less.

The composition of the monomer component constituting the base polymer of the A layer can be set so that Tg (that is, Tg _A ) determined by the Fox formula based on the composition of the monomer component is −10 ° C. or less. In some embodiments, Tg _A is advantageously −20 ° C. or lower, preferably −30 ° C. or lower, more preferably −40 ° C. or lower, and −50 ° C. or lower. Is more preferable, and may be, for example, −55 ° C. or lower. When Tg _A is lowered, the adhesion of the A layer to the adherend generally tends to be improved. According to the A layer having high adhesion to the adherend, it is easy to suppress the positional deviation and lifting of the pressure-sensitive adhesive sheet attached to the adherend. On the other hand, from the viewpoint of increasing the peel strength after increasing the peel strength, Tg _A may be, for example, −70 ° C. or higher, and may be −65 ° C. or higher.

In some embodiments, the glass transition Tg _A of the base polymer of the A layer and the glass transition Tg _B [° C.] of the base polymer of the B layer are preferably set to be higher than Tg _A [° C.], and Tg _B Is more preferably set to be 10 ° C. or more higher than Tg _A. Thereby, before sticking to a to-be-adhered body, a peeling force raising agent is appropriately stored in B layer, and after sticking to a to-be-adhered body, the peeling power raising agent in B layer is efficiently turned into A layer. Supplying can effectively improve the peeling force. In some embodiments, Tg _B may be 15 ° C. or more or 20 ° C. or more higher than Tg _A.

The layer A can be formed using a pressure-sensitive adhesive composition containing the monomer component having the above-described composition in the form of a polymer, an unpolymer, or a mixture thereof. The pressure-sensitive adhesive composition can be in various forms such as a water-dispersed pressure-sensitive adhesive composition, a solvent-type pressure-sensitive adhesive composition, an active energy ray-curable pressure-sensitive adhesive composition, and a hot-melt pressure-sensitive adhesive composition.

The pressure-sensitive adhesive sheet according to some preferred embodiments has an A layer formed from a water-dispersed pressure-sensitive adhesive composition. A typical example of the water-dispersed pressure-sensitive adhesive composition is an emulsion-type pressure-sensitive adhesive composition. The emulsion-type pressure-sensitive adhesive composition typically contains an emulsion polymer of monomer components and additives that are used as necessary.

The emulsion polymerization of the monomer component is usually performed in the presence of an emulsifier. The emulsifier for emulsion polymerization is not particularly limited, and known anionic emulsifiers, nonionic emulsifiers, and the like can be used. An emulsifier can be used individually by 1 type or in combination of 2 or more types.

Non-limiting examples of anionic emulsifiers include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzene sulfonate, sodium polyoxyethylene lauryl sulfate, sodium polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl phenyl ether ammonium sulfate, polyoxy Examples include sodium ethylene alkylphenyl ether sulfate and sodium polyoxyethylene alkyl sulfosuccinate. Non-limiting examples of nonionic emulsifiers include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene polyoxypropylene block polymer, and the like. An emulsifier having a reactive functional group (reactive emulsifier) may be used. Examples of the reactive emulsifier include a radical polymerizable emulsifier having a structure in which a radical polymerizable functional group such as a propenyl group or an allyl ether group is introduced into the anionic emulsifier or the nonionic emulsifier described above.

The amount of the emulsifier used in the emulsion polymerization may be, for example, 0.2 parts by weight or more, 0.5 parts by weight or more, 1.0 part by weight or more with respect to 100 parts by weight of the monomer component. It may be 5 parts by weight or more. Further, from the viewpoint of easily increasing the peel strength after increasing the peel strength, the amount of the emulsifier is usually suitably 10 parts by weight or less with respect to 100 parts by weight of the monomer component, and 5 parts by weight or less. Preferably, it may be 3 parts by weight or less. In addition, the emulsifier used here for emulsion polymerization can function also as a water affinity agent of A layer.

According to emulsion polymerization, a polymerization reaction liquid in the form of an emulsion in which a polymer of monomer components is dispersed in water is obtained. The water-dispersed pressure-sensitive adhesive composition used for forming the A layer can be preferably produced using the polymerization reaction solution.

(Water affinity agent)
In some embodiments of the pressure-sensitive adhesive sheet disclosed herein, the A layer constituting the pressure-sensitive adhesive surface may contain a water affinity agent in addition to the base polymer. For example, a pressure-sensitive adhesive sheet including an acrylic polymer as a base polymer and further having an A layer containing a water affinity agent is preferable. By using the water-affinity agent, the water peeling force of the pressure-sensitive adhesive sheet can be effectively reduced and the reworkability can be further improved at least at the initial stage of application to the adherend.

As the water-affinity agent, various materials can be appropriately selected and used by being contained in the A layer and capable of exhibiting the action of enhancing the water affinity of the surface of the A layer (that is, the adhesive surface). By increasing the water affinity of the A layer, an aqueous liquid such as water can be more quickly adapted to the surface of the A layer. Thereby, for example, when the adhesive sheet is peeled off with water, the first drop of water can be suitably distributed on the surface of the layer A following the movement of the peeling front of the adhesive sheet from the adherend. It is possible to effectively reduce the water peeling force. In the pressure sensitive adhesive sheet peeling method including moving the peeling front while allowing an aqueous liquid such as water to enter the interface between the pressure sensitive adhesive sheet and the adherend by the same action, the peelability of the pressure sensitive adhesive sheet from the adherend is increased. Can be increased.

As the water affinity agent, known anionic surfactants, nonionic surfactants, cationic surfactants, water-soluble plasticizers, water-soluble polymers, and the like can be used. A water affinity agent can be used individually or in combination of 2 or more types.

As the water-soluble plasticizer, various polyols (preferably polyether polyols) can be used. Specific examples include polyethylene glycol, polypropylene glycol, polyoxypropylene sorbitol ether, polyglycerin and the like. These can be used alone or in combination of two or more.
Examples of the water-soluble polymer include polyvinyl alcohol, polyvinyl pyrrolidone, and polyacrylic acid.

Examples of the anionic surfactant include alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate; alkyl sulfates such as sodium lauryl sulfate and ammonium lauryl sulfate; polyether amines such as polyoxyethylene lauryl amine and polyoxyethylene stearyl amine; Polyether sulfates such as sodium polyoxyethylene alkyl ether sulfate, ammonium polyoxyethylene alkyl phenyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate; polyoxyethylene stearyl ether phosphate, polyoxyethylene lauryl ether phosphate, etc. Polyoxyethylene alkyl ether phosphate; of the above polyoxyethylene alkyl ether phosphate Thorium salts, polyoxyethylene alkyl ether phosphoric acid ester salts such as potassium salts; polyoxyethylene alkyl sodium sulfosuccinate, and the like.

Nonionic surfactants include, for example, polyoxyalkylene ethers such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene glyceryl ether, polyoxypropylene glyceryl ether, polyoxyethylene bisphenol A ether; polyoxyethylene Examples thereof include fatty acid esters and polyoxyethylene / polyoxypropylene block polymers.

In some embodiments, for example, an anionic surfactant having at least one of a —POH group, a —COH group, and a —SOH group may be preferably used. Of these, surfactants having —POH groups are preferred. Such surfactants typically contain a phosphate ester structure, such as monoesters of phosphoric acid (ROP (= O) (OH) ₂ ; where R is a monovalent organic group), diesters ((RO) ₂ P (═O) OH; where R is the same or different monovalent organic group), a mixture containing both a monoester and a diester, and the like. A preferred example of the surfactant having a —POH group is polyoxyethylene alkyl ether phosphate. The number of carbon atoms of the alkyl group in the polyoxyethylene alkyl ether phosphate ester may be, for example, 6 to 20, 8 to 20, 10 to 20, 12 to 20, or 14 to 20.

The content of the water affinity agent in the A layer is not particularly limited. In some embodiments, the content of the water-affinity agent may be, for example, 0.2 parts by weight or more per 100 parts by weight of the monomer component constituting the layer A, and 0.5 parts by weight from the viewpoint of obtaining a higher effect. The above may be sufficient, 1.0 weight part or more may be sufficient, and 1.5 weight part or more may be sufficient. In addition, from the viewpoint of suppressing excessive water diffusion into the bulk of the layer A, in some embodiments, the amount of the water-affinity agent is suitably 10 parts by weight or less with respect to 100 parts by weight of the monomer component. Yes, preferably 5 parts by weight or less, and may be 3 parts by weight or less. It is preferable that the content of the water-affinity agent is not too large from the viewpoint of increasing the peeling force after the peeling strength increasing agent supplied from the B layer exhibits its action.

(Tackifying resin)
The A layer may contain a tackifying resin. Examples of the tackifying resin include petroleum-based tackifying resins, terpene-based tackifying resins, phenol-based tackifying resins, and ketone-based tackifying resins, including rosin-based tackifying resins and rosin derivative tackifying resins. . These can be used alone or in combination of two or more.

Examples of the rosin-based tackifying resin include a rosin such as gum rosin, wood rosin, tall oil rosin, a stabilized rosin (for example, a stabilized rosin obtained by disproportionating or hydrogenating the rosin), a polymerized rosin (for example, Rosin multimers, typically dimers), modified rosins (eg, unsaturated acid-modified rosin modified with an unsaturated acid such as maleic acid, fumaric acid, (meth) acrylic acid, etc.) Can be mentioned.
Examples of the rosin derivative tackifier resin include esterified products of the rosin-based tackifier resin (for example, rosin esters such as stabilized rosin ester and polymerized rosin ester), and phenol-modified products of the rosin-based resin (phenol-modified rosin). ) And esterified products thereof (phenol-modified rosin ester) and the like.
Examples of the petroleum-based tackifier resins include aliphatic petroleum resins, aromatic petroleum resins, copolymerized petroleum resins, alicyclic petroleum resins, and hydrides thereof.
Examples of the terpene tackifying resin include α-pinene resin, β-pinene resin, aromatic modified terpene resin, terpene phenol resin, and the like.
Examples of the ketone-based tackifying resin include ketone-based resins obtained by condensation of ketones (for example, aliphatic ketones such as methyl ethyl ketone, methyl isobutyl ketone, and acetophenone; alicyclic ketones such as cyclohexanone and methylcyclohexanone) and formaldehyde. And the like.

In some embodiments of the pressure-sensitive adhesive sheet disclosed herein, as the tackifier resin, one or more selected from rosin-based tackifier resins, rosin derivative tackifier resins, and terpene phenol resins can be preferably used. . Of these, rosin derivative tackifying resins are preferred, and preferred examples include rosin esters such as stabilized rosin esters and polymerized rosin esters.

In the water-dispersed pressure-sensitive adhesive composition, it is preferable to use a water-dispersed tackifying resin in a form in which the above-mentioned tackifying resin is dispersed in an aqueous solvent. For example, a pressure-sensitive adhesive composition containing these components in a desired ratio can be easily prepared by mixing an aqueous dispersion of an acrylic polymer and a water-dispersed tackifier resin. In some embodiments, as the water-dispersed tackifying resin, a resin substantially not containing at least an aromatic hydrocarbon solvent can be preferably used from the viewpoint of consideration for environmental hygiene. It is more preferable to use a water-dispersed tackifying resin that does not substantially contain an aromatic hydrocarbon solvent or other organic solvent.

Examples of commercially available water-dispersed tackifying resins containing rosin esters include “Super Ester E-720”, “Super Ester E-730-55”, and “Super Ester E-” manufactured by Arakawa Chemical Co., Ltd. 865NT ”, trade names“ Hari Star SK-90D ”,“ Harri Star SK-70D ”,“ Harri Star SK-70E ”,“ Neotor 115E ”manufactured by Harima Kasei Co., Ltd., and the like. Commercially available terpene phenol resins (which may be in the form of water-dispersed terpene phenol resins) include “Tamanor E-100”, “Tamanor E-200”, “Tamanor” manufactured by Arakawa Chemical Industries, Ltd. E-200NT "and the like.

The softening point of the tackifier resin is not particularly limited. From the viewpoint of suppressing a decrease in cohesive strength of the pressure-sensitive adhesive layer, usually a tackifying resin having a softening point of 80 ° C. or higher can be preferably used. The softening point of the tackifying resin may be 90 ° C. or higher, 100 ° C. or higher, 110 ° C. or higher, or 120 ° C. or higher. A tackifying resin having a softening point of 130 ° C or higher or 140 ° C or higher may be used. Further, from the viewpoint of transparency and adhesion to an adherend, a tackifier resin having a softening point of 200 ° C. or lower or 180 ° C. or lower can be preferably used. In addition, as a softening point of tackifying resin here, the nominal value described in literature, a catalog, etc. is employable. When there is no nominal value, the softening point of the tackifier resin can be measured based on the softening point test method (ring ball method) defined in JIS K5902 or JIS K2207.

The amount of the tackifier resin used in the A layer is usually 1 part by weight or more with respect to 100 parts by weight of the monomer component constituting the base polymer of the A layer, from the viewpoint of suitably exhibiting the use effect. It may be 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, or 25 parts by weight or more. In addition, from the viewpoint of achieving a good balance between adhesion to the adherend and cohesion, the amount of the tackifier resin used relative to 100 parts by weight of the monomer component may be, for example, 70 parts by weight or less, and even 50 parts by weight or less. It may be 40 parts by weight or less. Or A layer which does not contain tackifying resin substantially may be sufficient.

In addition, you may contain tackifying resin in B layer. The tackifying resin to be contained in the B layer can be appropriately selected from the above-mentioned examples regarding the tackifying resin that can be contained in the A layer. The above illustration regarding the amount of the tackifying resin used in the A layer can be applied to the amount of the tackifying resin used in the B layer. The technology disclosed herein includes, for example, an embodiment in which the B layer contains a tackifying resin and the A layer does not contain a tackifying resin; the A layer contains a tackifying resin, and the B layer does not contain a tackifying resin; The embodiment can be carried out in any manner, such as an embodiment in which each of the A layer and the B layer contains the same or different tackifying resin; an embodiment in which neither the A layer nor the B layer contains a tackifying resin;

The A layer may contain the same or different peel strength improver as the B layer as long as the effects of the present invention are not significantly impaired. For example, the A layer may contain a silane coupling agent. Regardless of whether the A layer contains a peel strength improver or not, a peel strength increasing agent supplied from the B layer by supplying a peel strength increasing agent from the B layer to the A layer after application to the adherend The effect of improving the peeling force by the action of can be exhibited.

When the A layer contains a silane coupling agent, the amount used can be set so as to obtain a desired use effect, and is not particularly limited. In some embodiments, the amount of the silane coupling agent used in the A layer may be, for example, 0.001 part by weight or more with respect to 100 parts by weight of the monomer component constituting the A layer, thereby obtaining a higher effect. From the viewpoint, it may be 0.005 parts by weight or more, 0.01 parts by weight or more, or 0.015 parts by weight or more. Further, from the viewpoint of improving adhesion to the adherend, in some embodiments, the amount of the silane coupling agent used is, for example, 3 parts by weight or less with respect to 100 parts by weight of the monomer component constituting the A layer. It may be 1 part by weight or less, or 0.5 part by weight or less. In addition, in the aspect in which a monomer component contains an alkoxy silyl group containing monomer, you may utilize the said alkoxy silyl group containing monomer as a part or all of the silane coupling agent contained in A layer.

In an embodiment in which the pressure-sensitive adhesive layer includes an A layer and a B layer and not only the B layer but also the A layer includes a peeling force increasing agent, the concentration C _B [wt%] of the peeling force increasing agent in the _B layer is It is preferable that it is higher than the concentration C _A [wt%] of the above-mentioned peeling force increasing agent. According to the pressure-sensitive adhesive sheet having such a configuration, the peeling force increasing agent in the B layer can be more efficiently transferred to the A layer using the concentration gradient after being attached to the adherend, and the peeling force is effective. Can be improved. In some embodiments, the ratio of the B layer peel strength enhancer concentration C _B to the B layer peel strength enhancer concentration C _A , ie, C _B / C _A may be, for example, 1.5 or greater. It is preferably 0 or more, more preferably 8.0 or more, and may be 10 or more, 12 or more, or 15 or more. The upper limit of C _B / C _A is not particularly limited. For example, it may be 200 times or less, 100 times or less, or 50 times or less.

The pressure-sensitive adhesive composition used for forming the A layer may contain an acid or a base (ammonia water or the like) used for the purpose of adjusting pH, if necessary. Other optional components that can be contained in the composition include viscosity modifiers (eg, thickeners), leveling agents, plasticizers, fillers, colorants such as pigments and dyes, stabilizers, preservatives, and anti-aging agents. Examples of various additives that are common in the field of pressure-sensitive adhesive compositions. About such various additives, conventionally well-known things can be used by a conventional method, and since it does not characterize this invention in particular, detailed description is abbreviate | omitted.

In some embodiments, the B layer may be a layer formed from a photocurable pressure-sensitive adhesive composition or a solvent-type pressure-sensitive adhesive composition. The pressure-sensitive adhesive sheet disclosed herein includes, for example, an embodiment having a combination of a layer A formed from a water-dispersed pressure-sensitive adhesive composition and a layer B formed from a photocurable pressure-sensitive adhesive composition, or a water-dispersed pressure-sensitive adhesive. It can preferably be implemented in an embodiment having a combination of the A layer formed from the agent composition and the B layer formed from the solvent-type pressure-sensitive adhesive composition. In some embodiments, from the viewpoint of improving water resistance, a B layer substantially not containing a water-affinity agent can be preferably employed.

<Support>
The pressure-sensitive adhesive sheet according to some embodiments may be in the form of a pressure-sensitive adhesive sheet with a support including a support bonded to the other back surface of the pressure-sensitive adhesive layer. The material of the support is not particularly limited, and can be appropriately selected according to the purpose of use or usage of the pressure-sensitive adhesive sheet. Non-limiting examples of supports that can be used include polyolefin films based on polyolefins such as polypropylene and ethylene-propylene copolymers, polyester films based on polyesters such as polyethylene terephthalate and polybutylene terephthalate, Plastic films such as polyvinyl chloride films mainly composed of polyvinyl chloride; foam sheets made of foams such as polyurethane foam, polyethylene foam, polychloroprene foam; various fibrous materials (natural fibers such as hemp and cotton, Synthetic fibers such as polyester and vinylon, semi-synthetic fibers such as acetate, etc.) Woven and non-woven fabrics of single or mixed spinning, etc .; paper such as Japanese paper, fine paper, kraft paper, crepe paper; aluminum foil, Metal foil such as copper foil; It is. A support having a structure in which these are combined may be used. Examples of such a composite structure support include a support having a structure in which a metal foil and the plastic film are laminated, a plastic sheet reinforced with inorganic fibers such as glass cloth, and the like.

As the support for the pressure-sensitive adhesive sheet disclosed herein, various films (hereinafter also referred to as support films) can be preferably used. The support film may be a porous film such as a foam film or a non-woven sheet, or may be a non-porous film, and a porous layer and a non-porous layer are laminated. It may be a structured film. In some embodiments, the support film preferably includes a base film containing a resin film that can maintain its shape independently (either a self-supporting type or an independent type). Here, the “resin film” means a resin film having a non-porous structure and typically containing substantially no bubbles (voidless). Therefore, the said resin film is the concept distinguished from a foam film and a nonwoven fabric. The resin film may have a single-layer structure or a multilayer structure having two or more layers (for example, a three-layer structure).

Examples of the resin material constituting the resin film include polycycloolefin derived from a monomer having an aliphatic ring structure such as polyester, polyolefin, norbornene structure, polyamide (PA) such as nylon 6, nylon 66, and partially aromatic polyamide. , Polyimide (PI), polyamide imide (PAI), polyether ether ketone (PEEK), polyether sulfone (PES), polyphenylene sulfide (PPS), polycarbonate (PC), polyurethane (PU), ethylene-vinyl acetate copolymer (EVA), polystyrene, polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene (PTFE) and other fluororesins, polymethyl methacrylate and other acrylic resins, diacetylcellulose and triacetylcellulose It cellulosic polymers, vinyl butyral polymers, arylate polymers, polyoxymethylene-based polymer, the use of a resin such as an epoxy polymer. The resin film may be formed using a resin material containing one kind of such resin alone, or may be formed using a resin material in which two or more kinds are blended. Also good. The resin film may be unstretched or stretched (for example, uniaxially stretched or biaxially stretched).

Preferable examples of the resin material constituting the resin film include polyester resin, PPS resin, and polyolefin resin. Here, the polyester resin refers to a resin containing polyester in a proportion exceeding 50% by weight. Similarly, a PPS resin refers to a resin containing PPS in a proportion exceeding 50% by weight, and a polyolefin-based resin refers to a resin containing a polyolefin in a proportion exceeding 50% by weight.

As the polyester resin, typically, a polyester resin containing as a main component a polyester obtained by polycondensation of dicarboxylic acid and diol is used. Specific examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate, and the like.

As the polyolefin resin, one kind of polyolefin can be used alone, or two or more kinds of polyolefins can be used in combination. The polyolefin may be, for example, a homopolymer of α-olefin, a copolymer of two or more α-olefins, a copolymer of one or two or more α-olefins with other vinyl monomers, and the like. Specific examples include polyethylene (PE), polypropylene (PP), poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene copolymers such as ethylene propylene rubber (EPR), ethylene-propylene- Examples include butene copolymers, ethylene-butene copolymers, ethylene-vinyl alcohol copolymers, and ethylene-ethyl acrylate copolymers. Both low density (LD) polyolefins and high density (HD) polyolefins can be used. Examples of polyolefin resin films include unstretched polypropylene (CPP) film, biaxially stretched polypropylene (OPP) film, low density polyethylene (LDPE) film, linear low density polyethylene (LLDPE) film, and medium density polyethylene (MDPE). Examples thereof include a film, a high density polyethylene (HDPE) film, a polyethylene (PE) film obtained by blending two or more kinds of polyethylene (PE), and a PP / PE blend film obtained by blending polypropylene (PP) and polyethylene (PE).

Specific examples of the resin film that can be preferably used as the support include PET film, PEN film, PPS film, PEEK film, CPP film, and OPP film. Preferable examples in terms of strength include PET film, PEN film, PPS film, and PEEK film. A PET film is a preferred example from the viewpoint of availability, dimensional stability, optical properties, and the like.

The resin film may be blended with known additives such as light stabilizers, antioxidants, antistatic agents, colorants (dyes, pigments, etc.), fillers, slip agents, antiblocking agents, etc., as necessary. Can do. The compounding quantity of an additive is not specifically limited, According to the use etc. of an adhesive sheet, it can set suitably.

The method for producing the resin film is not particularly limited. For example, conventionally known general resin film molding methods such as extrusion molding, inflation molding, T-die casting, and calendar roll molding can be appropriately employed.

The support may be substantially composed of such a resin film. Alternatively, the support may include an auxiliary layer in addition to the resin film. Examples of the auxiliary layer include an optical property adjusting layer (for example, a colored layer or an antireflection layer), a printed layer or a laminate layer, an antistatic layer, or an undercoat layer for imparting a desired appearance to a support or an adhesive sheet. And a surface treatment layer such as a release layer. Further, the support member may be an optical member described later.

The thickness of the support is not particularly limited, and can be selected according to the purpose of use or usage of the pressure-sensitive adhesive sheet. The thickness of the support may be, for example, 1000 μm or less, 500 μm or less, 100 μm or less, 70 μm or less, 50 μm or less, 25 μm or less, 10 μm or less, or 5 μm or less. When the thickness of the support becomes small, the flexibility of the pressure-sensitive adhesive sheet and the followability to the surface shape of the adherend tend to improve. Further, from the viewpoints of handleability and workability, the thickness of the support may be, for example, 2 μm or more, and may be greater than 5 μm or greater than 10 μm. In some embodiments, the thickness of the support may be, for example, 20 μm or more, 35 μm or more, or 55 μm or more.

On the surface of the support that is to be bonded to the adhesive layer, corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, application of primer (primer), antistatic treatment, as necessary A conventionally well-known surface treatment, such as these, may be given. Such a surface treatment can be a treatment for improving the adhesion between the support and the pressure-sensitive adhesive layer, in other words, the anchoring property of the pressure-sensitive adhesive layer to the support. The composition of the primer is not particularly limited, and can be appropriately selected from known ones. The thickness of the undercoat layer is not particularly limited, but is usually about 0.01 μm to 1 μm, preferably about 0.1 μm to 1 μm.

On the surface of the support opposite to the side to be bonded to the pressure-sensitive adhesive layer (hereinafter also referred to as the back surface), if necessary, such as peeling treatment, adhesion or tackiness improving treatment, antistatic treatment, etc. A conventionally known surface treatment may be applied. For example, the rewinding force of the pressure-sensitive adhesive sheet wound in a roll shape can be reduced by surface-treating the back surface of the support with a release treatment agent. As the release treatment agent, a silicone release treatment agent, a long-chain alkyl release treatment agent, an olefin release treatment agent, a fluorine release treatment agent, a fatty acid amide release treatment agent, molybdenum sulfide, silica powder, or the like can be used. .

<Adhesive sheet>
The pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet disclosed herein can be a cured layer of the pressure-sensitive adhesive composition. That is, the pressure-sensitive adhesive layer can be formed by applying (for example, applying) the pressure-sensitive adhesive composition to an appropriate surface and then appropriately performing a curing treatment. When performing 2 or more types of hardening processes (drying, bridge | crosslinking, superposition | polymerization, etc.), these can be performed simultaneously or over multiple steps.
In an adhesive composition using a partially polymerized monomer component (acrylic polymer syrup), a final copolymerization reaction is typically performed as the curing treatment. That is, the partial polymer is subjected to a further copolymerization reaction to form a complete polymer. For example, if it is a photocurable adhesive composition, light irradiation is implemented. If necessary, curing treatment such as cross-linking and drying may be performed. For example, when it is necessary to dry with a photocurable pressure-sensitive adhesive composition (for example, in the case of a photocurable pressure-sensitive adhesive composition in a form in which a partially polymerized monomer component is dissolved in an organic solvent), the composition is dried. It is good to carry out photocuring after making it.
In the pressure-sensitive adhesive composition using a completely polymerized product, typically, as the curing treatment, treatments such as drying (heat drying) and crosslinking are performed as necessary. In the case of a solvent-type pressure-sensitive adhesive composition to which photocurability (photocrosslinkability) is imparted by adding a polyfunctional monomer, it is preferable to perform photocuring after drying the composition. Here, after the composition is dried, the pressure-sensitive adhesive sheet obtained through the drying may be bonded to an adherend. The pressure-sensitive adhesive sheet disclosed herein can be used in a mode in which the adhesive sheet is attached to the adherend by a method including photocuring after being attached to the adherend.
The pressure-sensitive adhesive layer having a multilayer structure of two or more layers can be prepared by bonding together a pressure-sensitive adhesive layer formed in advance. Alternatively, the second pressure-sensitive adhesive layer may be formed by applying a pressure-sensitive adhesive composition onto a previously formed first pressure-sensitive adhesive layer and curing the pressure-sensitive adhesive composition. When the pressure-sensitive adhesive layer used in the sticking mode for photocuring after bonding to an adherend has a multilayer structure, the pressure-sensitive adhesive layer to be photocured is a part of layers included in the multilayer structure ( For example, it may be one layer) or all layers.

The application of the pressure-sensitive adhesive composition can be carried out using a conventional coater such as a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray coater. In the pressure-sensitive adhesive sheet having a support, a direct method of directly forming the pressure-sensitive adhesive layer by directly applying the pressure-sensitive adhesive composition to the support may be used as a method for providing the pressure-sensitive adhesive layer on the support. You may use the transfer method which transcribe | transfers the adhesive layer formed on the surface to a support body.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, and can be, for example, about 3 μm to 2000 μm. In some embodiments, the pressure-sensitive adhesive layer may have a thickness of, for example, 5 μm or more, 10 μm or more, or 20 μm or more from the viewpoint of improving the water resistance reliability by closely attaching the pressure-sensitive adhesive layer to the adherend. 30 μm or more, 50 μm or more, more than 50 μm, 70 μm or more, 100 μm or more, or 120 μm or more. Further, from the viewpoint of preventing generation of adhesive residue due to cohesive failure of the pressure-sensitive adhesive layer, in some embodiments, the thickness of the pressure-sensitive adhesive layer may be, for example, 1000 μm or less, 700 μm or less, or 500 μm or less. 300 μm or less, 200 μm or less, or 170 μm or less. The technique disclosed here can be suitably implemented even in the form of a pressure-sensitive adhesive sheet in which the thickness of the pressure-sensitive adhesive layer is 130 μm or less, 90 μm or less, 60 μm or less, or 40 μm or less. In the pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer having a multilayer structure of two or more layers, the thickness of the pressure-sensitive adhesive layer is the thickness from the pressure-sensitive adhesive surface attached to the adherend to the surface opposite to the pressure-sensitive adhesive surface. Say it. For example, in a two-layered pressure-sensitive adhesive layer composed of a layer A constituting the pressure-sensitive adhesive surface and a layer B laminated on the back surface, the thickness from the pressure-sensitive adhesive surface to the back surface of the B layer is referred to and used as necessary. The thickness of the resulting support is not included. On the other hand, in such a two-layered pressure-sensitive adhesive layer, when a peeling force increasing agent layer is disposed between the A layer and the B layer, the thickness of the peeling force increasing agent layer is the same as the pressure-sensitive adhesive layer. Included in thickness.

In the configuration in which the pressure-sensitive adhesive layer includes the A layer and the B layer, the thickness of the A layer may be, for example, 1 μm or more, 2 μm or more, or 5 μm or more. In the pressure-sensitive adhesive sheet having a configuration in which the B layer is a peeling force increasing agent supply unit and the B layer is separated from the pressure-sensitive adhesive surface by the A layer as a surface portion, a period during which rework is possible after application to an adherend (that is, From the viewpoint of facilitating securing at least about 1 day of the period until the peel force is greatly increased by the action of the peel force increasing agent transferred from the B layer, the thickness of the A layer is preferably 10 μm or more, and 15 μm. More preferably.
Further, the thickness of the A layer may be, for example, 100 μm or less, usually preferably 50 μm or less, 45 μm or less, 35 μm or less, or 25 μm or less. The fact that the thickness of the A layer is not too large means that after application to the adherend, the period of time until the adhesive force increases due to the action of the peeling force increasing agent becomes too long (for example, the peeling force at room temperature for 30 days is too long). It is advantageous from the viewpoint of avoiding that it does not rise sufficiently. Moreover, in the aspect provided with the A layer formed from the water-dispersed pressure-sensitive adhesive composition part or the aspect in which the A layer contains a water-affinity agent, the thickness of the A layer is not too large. From the viewpoint of the above.

In the pressure-sensitive adhesive sheet disclosed herein, the separation force increase supplied from the B layer after being applied to the adherend due to the separation (for example, the thickness of the A layer) from the peel strength increasing agent supply unit to the pressure-sensitive adhesive surface in this way. The time when the peeling force increases by the action of the agent can be adjusted. Other factors that can be used to control the timing of the release force increase include selection of the type of release force increasing agent, the concentration of the release force increasing agent in the B layer, and the Tg of the base polymer of the A layer (ie, Tg _A ) and the like. A person skilled in the art can understand the means for adjusting the rising time of the peeling force by performing a simple confirmation experiment as necessary based on the disclosure and technical common sense of the present specification.

In the embodiment in which the pressure-sensitive adhesive layer includes the A layer and the B layer, the thickness of the B layer may be 2 μm or more, 3 μm or more, 5 μm or more, or 10 μm or more, for example. From the viewpoint of better exhibiting the effect of providing the B layer on the back side of the A layer, in some embodiments, the thickness of the B layer may be, for example, 20 μm or more, 30 μm or more, or 50 μm or more. It may be 70 μm or more, 100 μm or more, or 120 μm or more. The upper limit of the thickness of B layer is not specifically limited, For example, it may be 900 micrometers or less, 600 micrometers or less, 400 micrometers or less, or 250 micrometers or less.

In the embodiment in which the pressure-sensitive adhesive layer includes the A layer and the B layer, the thickness of the A layer in the total thickness of the pressure-sensitive adhesive layer may be, for example, 90% or less, and is usually preferably 70% or less. 50% or less, 30% or less, 20% or less, or 15% or less. Moreover, from the viewpoint of easy formation of the A layer and water peelability of the pressure-sensitive adhesive sheet, in some embodiments, the thickness of the A layer in the total thickness of the pressure-sensitive adhesive layer may be, for example, 3% or more. It may be 5% or more, 7% or more, or 10% or more.

<Characteristics of adhesive sheet>
According to this specification, for example, an adhesive sheet satisfying one or more of the following (a) to (h) can be provided.
(A) A normal peeling force FN1 measured under conditions of a tensile speed of 60 mm / min and a peeling angle of 180 degrees after 1 day at room temperature after affixing the adhesive surface to an adherend is 2.8 N / cm or less, and The peel strength FN30, which is measured under conditions of a tensile speed of 60 mm / min and a peel angle of 180 degrees after 30 days of room temperature after the adhesive surface is attached to the adherend, is 3.0 N / cm or more.
(B) One day at room temperature after the adhesive surface is attached to the adherend, a drop of water is dropped on the adherend, and the water enters one end of the interface between the adhesive layer and the adherend. Then, the water peeling force FW1 measured under conditions of a tensile speed of 60 mm / min and a peeling angle of 180 degrees without supplying new water is less than 1.0 N / cm.
(C) The adhesive surface is attached to the adherend, and 30 days after room temperature, one drop of water is dropped on the adherend, and the water enters one end of the interface between the adhesive layer and the adherend. Then, the water peeling force FW30 measured under the conditions of a tensile speed of 60 mm / min and a peeling angle of 180 degrees without supplying new water is 2.0 N / cm or more.
(D) The normal peeling force FN30 is 3.0 N / cm or more, and the water peeling force FW1 is less than 1.0 N / cm.
(E) The normal peeling force FN1 is 2.8 N / cm or less, and the adhesive surface is attached to the adherend, and after 30 days at room temperature, and heated at 60 ° C. for 1 day, the tensile rate is 60 mm / min. The normal peeling force FNh30 measured under the condition of an angle of 180 degrees is 3.0 N / cm or more.
(F) The rate of increase of the normal peel force FN30 relative to the normal peel force FN1 (the peel force increase rate after 30 days) is 20% or more.
(G) The rate of increase of the normal peel force FNh30 with respect to the normal peel force FN1 (the rate of increase in peel strength after heat treatment) is 20% or more.
(H) The water peeling force FW1 is less than 1.0 N / cm, and the adhesive surface is attached to the adherend, and after 30 days at room temperature, heat treatment is performed at 60 ° C. for 1 day. A drop of water is dropped, and after the water has entered one end of the interface between the pressure-sensitive adhesive layer and the adherend, a tensile rate of 60 mm / min and a peeling angle of 180 degrees are performed without supplying new water. The water peeling force FWh30 measured under the conditions is 2.0 N / cm or more.

The normal peel force and the water peel force are measured by the following methods. The same measuring method is used in the examples described later.

[Measurement of normal peeling force FN]
A test piece is prepared by cutting the pressure-sensitive adhesive sheet to be measured into a rectangular shape having a width of 10 mm and a length of 120 mm. An evaluation sample in which the adhesive surface of the test piece is bonded to an adherend with a hand roller is placed in an autoclave and treated for 15 minutes under conditions of a pressure of 5 atm and a temperature of 50 ° C.
Usually, the peeling force FN1 [N / cm] is obtained by holding the sample for evaluation taken out from the autoclave in an environment of 23 ° C. and 50% RH for 1 day, and then cutting the sample at the interface between the test piece and the adherend in the same environment. One end of the test piece in the longitudinal direction is peeled off from the adherend by inserting a knife, and the peel strength is measured using a tensile tester in accordance with JIS Z0237 at a tensile speed of 60 mm / min and a peel angle of 180 degrees. . The measurement is performed three times, and the average value thereof is normally defined as a peeling force FN1 [N / cm].
For normal peel force FN3 [N / cm] and normal peel force FN30 [N / cm], the period for holding the sample for evaluation taken out from the autoclave in an environment of 23 ° C. and 50% RH is changed to 3 days and 30 days, respectively. Other than this, it is usually obtained in the same manner as the measurement of the peeling force FN1.
Usually, the peeling force FNh30 [N / cm] is maintained at 23 ° C. and 50% RH for 30 days, and then heat-treated at 60 ° C. for 1 day, and then 23 ° C. and 50% RH Other than measuring the peel strength under the environment, it is usually obtained in the same manner as the measurement of the peel force FN30.
Moreover, the normal peeling force FNi [N / cm] described later is the same as the measurement of the normal peeling force FN1 except that the evaluation sample taken out from the autoclave is kept at 23 ° C. and 50% RH for 30 minutes. It is obtained in the same way.

[Measurement of water peeling force FW]
A test piece is prepared by cutting the pressure-sensitive adhesive sheet to be measured into a rectangular shape having a width of 10 mm and a length of 120 mm. An evaluation sample in which the layer A side of the test piece is bonded to an adherend with a hand roller is put into an autoclave and treated for 15 minutes under conditions of a pressure of 5 atm and a temperature of 50 ° C.
The water peeling force FW1 [N / cm] is obtained by holding the sample for evaluation taken out from the autoclave in an environment of 23 ° C. and 50% RH for one day, and in the same environment, the one end near the one end in the longitudinal direction of the test piece. 1 drop (about 10 μl to about 40 μl) of distilled water is dropped on the surface of the adherend exposed from the substrate. And after inserting a cutter knife in the interface of a test piece and a to-be-adhered body, and making the said water approach into the said interface, using a tensile testing machine according to JISZ0237, without supplying new water. The peel strength is measured under the conditions of a tensile speed of 60 mm / min and a peel angle of 180 degrees. The measurement is performed three times, and the average value thereof is defined as a water peeling force FW1 [N / cm].
Water stripping force FW3 [N / cm] and water stripping force FW30 [N / cm] were changed to 3 days and 30 days, respectively, for maintaining the sample for evaluation taken out of the autoclave in an environment of 23 ° C. and 50% RH. Other than this, it is obtained in the same manner as the measurement of the water peeling force FW1.
The water peeling force FWh30 [N / cm] was maintained at 23 ° C. and 50% RH for 30 days, and then heat-treated at 60 ° C. for 1 day, and then 23 ° C. and 50% RH Other than measuring the peel strength under the environment, it is obtained in the same manner as the measurement of the water peel force FW30.
In addition, the water peeling force FWi [N / cm] described later is the same as the measurement of the water peeling force FN1 except that the evaluation sample taken out from the autoclave is kept in an environment of 23 ° C. and 50% RH to 30 minutes. It is obtained in the same way.
In addition, the water used in the measurement of the water peeling force FW is only one drop of distilled water dropped on the adherend before the peeling starts.

In the above-described measurement of the normal peeling force and the water peeling force, an alkali glass plate is used as the adherend. For example, an alkali glass plate (thickness 1.35 mm, blue plate edge polished product) manufactured by Matsunami Glass Industrial Co., Ltd. or its equivalent can be used as the adherend. The test piece is attached to the adherend so that the distance from the outer peripheral end of the test piece to the outer peripheral end of the adherend is at least 1 mm or more, preferably 3 mm or more.
In the pressure-sensitive adhesive sheet to which a sticking mode in which a part or all of the pressure-sensitive adhesive layer is photocured after being attached to the adherend is applied, the sample for evaluation taken out from the autoclave is subjected to an environment of 23 ° C. and 50% RH. Light irradiation is performed through the alkali glass plate.
As the tensile tester, a universal tensile compression tester (device name “Tension / Compression Tester, TCM-1kNB” manufactured by Minebea Co., Ltd.) or an equivalent thereof can be used. The peel strength is measured so that the test piece attached to the adherend progresses upward from the bottom. In the measurement, a test piece can be reinforced by attaching an appropriate backing material to the back surface (surface opposite to the pressure-sensitive adhesive surface) of the pressure-sensitive adhesive sheet as necessary. As the backing material, for example, a PET film having a thickness of about 25 μm can be used.

The pressure-sensitive adhesive sheet satisfying the above (a) usually exhibits good reworkability at the initial stage of pasting because the peel force FN1 is 2.8 N / cm or less, and the normal peel force FN30 is 3 within 30 days from the pasting. It can be increased to 0.0 N / cm or more to improve the bonding reliability. The pressure-sensitive adhesive sheet satisfying the above (b) has a water peeling force FW1 of less than 1.0 N / cm, so that the pressure-sensitive adhesive sheet is peeled off using an aqueous liquid (typically water) at the initial stage of application. Thus, the pressure-sensitive adhesive sheet can be peeled from the adherend with a very light force. Such an adhesive sheet is excellent in reworkability.
In the pressure-sensitive adhesive sheet satisfying the above (c), the water peelability FW30 rises to 2.0 N / cm or more within 30 days from the pasting, and thus the water peelability is lost. Reliability can be demonstrated.
The pressure-sensitive adhesive sheet satisfying the above (d) can peel off the pressure-sensitive adhesive sheet from the adherend with a very light force by using an aqueous liquid (typically water) at the initial stage of sticking. Within 30 days, it is usually possible to increase the peeling force FN30 to 3.0 N / cm or more to improve the bonding reliability.
The pressure-sensitive adhesive sheet satisfying the above (e) usually exhibits good reworkability at the initial stage of application when the peeling force FN1 is 2.8 N / cm or less, and can improve the bonding reliability by the heat treatment. .
The pressure-sensitive adhesive sheet satisfying the above (f) exhibits good reworkability at the initial stage of pasting, and can usually increase the peel strength within 30 days from the pasting to enhance the joining reliability.
The pressure-sensitive adhesive sheet satisfying the above (g) exhibits good reworkability at the initial stage of pasting, and usually increases the peel strength by performing heat treatment at an appropriate timing after the pasting to increase the joining reliability. Can do.
The pressure-sensitive adhesive sheet satisfying the above (h) exhibits excellent water releasability at the initial stage of application, and disappears by performing heat treatment at an appropriate timing after application. And can exhibit good bonding reliability.

In some embodiments, the normal peeling force FN1 is preferably 2.5 N / cm or less, more preferably 2.0 N / cm or less, and 1.8 N / cm or less from the viewpoint of improving reworkability. More preferably it is. Usually, the lower limit of the peeling force FN1 is not particularly limited, but it is usually preferably 0.5 N / cm or more, and may be 0.7 N / cm or more, from the viewpoint of suppressing the positional deviation and lifting of the pressure-sensitive adhesive sheet. It may be 0 N / cm or more.
In some embodiments, the water peeling force FW1 is preferably 0.7 N / cm or less, more preferably 0.5 N / cm or less, from the viewpoint of improving reworkability, and 0.3 N / cm or less. More preferably it is. The lower limit of the water peeling force FW1 is not particularly limited, and may be substantially 0 N / cm, 0.01 N / cm or more, or 0.03 N / cm or more.
Usually, the peel force FN1 and / or the water peel force FW1 is low, for example, a thin adherend, a brittle adherend, an adherend that easily deforms (elongates, bends, twists, etc.), and a thin film that easily damages the surface. This is particularly significant in a pressure-sensitive adhesive sheet that is attached to an adherend having, for example.
In addition, from the viewpoint of improving reworkability, a pressure-sensitive adhesive sheet that peels from the adherend without causing the pressure-sensitive adhesive to remain on the adherend is preferable in the measurement of the normal peel force FN1 and the water peel force FW1. That is, an adhesive sheet excellent in non-glue residue is preferable. The presence or absence of the pressure-sensitive adhesive can be grasped, for example, by visually observing the adherend after peeling off the pressure-sensitive adhesive sheet.

In some embodiments, the normal peeling force FN30 is preferably 4.5 N / cm or more, more preferably 5.5 N / cm or more, and more preferably 6.5 N / cm or more from the viewpoint of bonding reliability. More preferably, it may be 7.5 N / cm or more or 8.0 N / cm or more. Usually, the upper limit of the peeling force FN30 is not particularly limited, but in consideration of the balance with other characteristics, it is usually suitably 25 N / cm or less, may be 20 N / cm or less, 15 N / cm or less, or 10 N / Cm or less.
In some embodiments, the water peeling force FW30 is preferably 3.0 N / cm or more, more preferably 3.5 N / cm or more, from the viewpoint of bonding reliability (water resistance reliability) with respect to water. It may be 4.5 N / cm or more, 5.0 N / cm or more, 6.0 N / cm or more, or 7.0 N / cm or more. The upper limit of the water peeling force FW30 is not particularly limited, and may be, for example, 25 N / cm or less, 20 N / cm or less, 15 N / cm or less, 10 N / cm or less, or 8 N / cm or less.

In some embodiments, the normal peeling force FNh30 is preferably 4.5 N / cm or more, more preferably 5.5 N / cm or more, and more preferably 6.5 N / cm or more from the viewpoint of bonding reliability. More preferably, it may be 7.5 N / cm or more or 8.0 N / cm or more. Usually, the upper limit of the peeling force FNh30 is not particularly limited, but in consideration of the balance with other characteristics, it is usually appropriate to be 25 N / cm or less, 20 N / cm or less, 15 N / cm or less, or 10 N / Cm or less.
In some embodiments, the water peeling force FWh30 may be, for example, 2.0 N / cm or more, and is preferably 3.0 N / cm or more from the viewpoint of bonding reliability (water resistance reliability) with respect to water. It is more preferable that it is 0.5 N / cm or more, and it may be 5.5 N / cm or more, 6.5 N / cm or more, or 7.5 N / cm or more. The upper limit of the water peeling force FWh30 is not particularly limited, and may be, for example, 25 N / cm or less, 20 N / cm or less, 15 N / cm or less, or 10 N / cm or less.

The pressure-sensitive adhesive sheet disclosed herein preferably has a peel strength increase rate after 30 days represented by the following formula of 20% or more, more preferably 50% or more, and even more preferably 100% or more. . In some embodiments, the rate of increase in peel strength after 30 days may be, for example, 150% or more, 200% or more, 250% or more, 300% or more, or 400% or more. The upper limit of the peel force increase rate after 30 days is not particularly limited, and may be, for example, 1000% or less.
After 30 days, rate of increase in peel strength [%] = ((FN30−FN1) / FN1) × 100

The pressure-sensitive adhesive sheet disclosed herein preferably has an increase rate of peel strength after heat treatment represented by the following formula of 20% or more, more preferably 50% or more, and 100% or more. Further preferred. In some embodiments, the rate of increase in peel strength after 30 days may be, for example, 150% or more, 200% or more, more than 200%, 250% or more, 350% or more, or 400% or more. 450% or more. The upper limit of the peel force increase rate after heat treatment is not particularly limited, and may be, for example, 1000% or less.
Increase rate of adhesive strength after heat treatment [%] = ((FNh30−FN1) / FN1) × 100

The pressure-sensitive adhesive sheet disclosed herein preferably has a one-day water-removal adhesive strength reduction rate of 65% or more represented by the following formula.
After 1 day, the rate of decrease in water peel adhesion [%] = (1− (FW1 / FN1)) × 100

After 1 day, the pressure-sensitive adhesive sheet having a high water peeling adhesive strength reduction rate is peeled off using an aqueous liquid such as water, whereby the load applied to the adherend during peeling can be significantly reduced. For example, a small amount of aqueous liquid is supplied to the adherend to which the adhesive sheet is affixed, and the aqueous liquid is caused to enter the interface between the adhesive sheet and the adherend from one end of the adhesive sheet. The peel strength of the pressure-sensitive adhesive sheet from the adherend can be greatly reduced by peeling the pressure-sensitive adhesive sheet after it is made. Utilizing this property, it is possible to achieve both the performance of suppressing the positional deviation and lifting of the pressure-sensitive adhesive sheet attached to the adherend and good reworkability. In some embodiments, the rate of decrease in adhesive strength after one day may be, for example, 70% or more, 75% or more, 80% or more, or 85% or more. After one day, the rate of decrease in water peel adhesion is 100% or less in principle, and typically less than 100%.

The pressure-sensitive adhesive sheet disclosed herein preferably has a 30-day water-removal adhesive strength reduction rate represented by the following formula of 55% or less.
After 30 days, the rate of decrease in water peel adhesion [%] = (1− (FW30 / FN30)) × 100

When the pressure-sensitive adhesive sheet has a low rate of decrease in water-peeling adhesive strength after 30 days, it becomes difficult to water-peel the pressure-sensitive adhesive sheet at least 30 days after application, and water-reliable and reliable bonding can be realized. In some embodiments, the water peel adhesion reduction rate after 30 days may be, for example, 45% or less, 35% or less, 30% or less, 25% or less, 15% or less, or 10% or less. But you can.

The pressure-sensitive adhesive sheet disclosed herein may have a post-heat treatment water peeling pressure reduction rate of 40% or less represented by the following formula.
Reduction rate of water peel adhesion after heat treatment [%] = (1− (FWh30 / FNh30)) × 100

According to the pressure-sensitive adhesive sheet having a low rate of decrease in water-peeling adhesive strength after heat treatment, it becomes difficult to water-separate the pressure-sensitive adhesive sheet after the heat treatment, and water-resistant and reliable bonding can be realized. In some embodiments, the post-heat treatment water peeling adhesion reduction rate may be, for example, 30% or less, 20% or less, 15% or less, or 10% or less.

In the pressure-sensitive adhesive sheet disclosed herein, it is preferable that at least the pressure-sensitive adhesive constituting the surface portion on the pressure-sensitive adhesive layer side of the pressure-sensitive adhesive layer is water-insoluble. According to such an adhesive layer, it is easy to obtain an adhesive sheet having a low water peeling force FW1. It is preferable that the surface portion is water-insoluble from the viewpoint of preventing the phenomenon that the pressure-sensitive adhesive remains on the adherend in peeling using an aqueous liquid such as water. In addition, the water-insoluble surface portion can be advantageous from the viewpoint of suppressing a decrease in transparency due to water immersion or environmental moisture.

In the pressure-sensitive adhesive sheet disclosed herein, it is preferable that at least the pressure-sensitive adhesive constituting the surface portion on the pressure-sensitive adhesive side of the pressure-sensitive adhesive layer is non-water-swellable. According to such an adhesive layer, it is easy to obtain an adhesive sheet having a low water peeling force FW1. Further, in peeling using an aqueous liquid such as water, good peeling properties can be exhibited by effectively using a small amount of an aqueous liquid. It is preferable that the surface portion is non-water-swellable from the viewpoint of preventing a phenomenon in which the adhesive remains on the adherend during peeling using an aqueous liquid. In addition, the non-water-swelling property of the surface portion can be advantageous from the viewpoint of suppressing a decrease in transparency due to water immersion or environmental moisture.

Here, in this specification, that the pressure-sensitive adhesive is water-insoluble means that the gel fraction measured by the following method is 75% or more. Moreover, that an adhesive is non-water-swellable means that the swelling degree measured by the following method is 2 or less.
That is, about 0.5 g of the pressure-sensitive adhesive to be measured is weighed, and its weight is defined as W1. The pressure-sensitive adhesive is immersed in 500 ml of distilled water for 48 hours at room temperature (about 23 ° C.), then filtered through a nylon mesh, and the weight W2 of the pressure-sensitive adhesive containing water is measured. Thereafter, the pressure-sensitive adhesive is dried at 130 ° C. for 5 hours, and the weight W3 of the nonvolatile content is measured. The gel fraction and the degree of swelling are calculated by the following equations.
Gel fraction [%] = (W3 / W1) × 100
Swelling degree = W2 / W1

In some embodiments, the gel fraction of the pressure-sensitive adhesive (for example, the above-described A layer) constituting the surface portion may be, for example, 80% or more, 90% or more, 95% or more, 98 % Or more. The gel fraction of the A layer is 100% or less in principle. In some embodiments, the swelling degree of the A layer may be, for example, 1.7 or less, 1.5 or less, or 1.2 or less. The degree of swelling of the A layer is usually 1.0 or more, and typically exceeds 1.0.

In the pressure-sensitive adhesive sheet having a configuration in which the pressure-sensitive adhesive layer includes the layer A and the layer B disposed on the back side of the layer A, the gel fraction of the layer B is not particularly limited. In some embodiments, the gel fraction of the B layer is preferably equal to or greater than the gel fraction of the A layer, and may be higher than the gel fraction of the A layer. The gel fraction of the B layer may be 90% or more, for example, 95% or more, 98% or more, or 99% or more. The gel fraction of the B layer is 100% or less in principle. Moreover, the gel fraction of the whole adhesive layer may be 85% or more, for example, 90% or more, 95% or more, 98% or more, or 99% or more. In addition, in the adhesive layer which consists only of A layers, the gel fraction of this whole adhesive layer means the gel fraction of A layer.

In the pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer includes the A layer and the B layer disposed on the back side of the A layer, the swelling degree of the B layer is not particularly limited. In some embodiments, the swelling degree of the B layer is preferably equal to or less than the swelling degree of the A layer, and may be lower than the swelling degree of the A layer. The swelling degree of the B layer may be, for example, 1.5 or less, 1.3 or less, or 1.1 or less. The swelling degree of the B layer is usually 1.0 or more, and typically exceeds 1.0. Moreover, the swelling degree of the whole adhesive layer may be 1.6 or less, for example, 1.4 or less, 1.2 or less, or 1.1 or less. In addition, in the adhesive layer which consists only of A layer, the swelling degree of this whole adhesive layer means the swelling degree of A layer.

It should be noted that the gel fraction and the degree of swelling of the pressure-sensitive adhesive with respect to water are commonly used for those skilled in the art at the time of filing the present application, such as the composition of the monomer component, the weight average molecular weight of the polymer, and the use of a crosslinking agent or a polyfunctional monomer. Can be adjusted by adopting as appropriate.

In the pressure-sensitive adhesive sheet having a configuration in which the pressure-sensitive adhesive layer includes the A layer and the B layer disposed on the back side of the A layer, one surface of the pressure-sensitive adhesive layer is the surface of the A layer, and the other surface is the surface of the B layer. , The normal peeling force FN1 [N / cm] measured by attaching the surface of the A layer to the adherend (the above-mentioned alkali glass plate) is measured by attaching the surface of the B layer to the adherend. It is preferably lower than the normal adhesive strength BN1 [N / cm]. For example, as an adhesive constituting the A layer, an adhesive layer having a lower FN1 than BN1 can be suitably formed by using an adhesive having a lower peel strength than the adhesive constituting the B layer. According to such a pressure-sensitive adhesive layer, a pressure-sensitive adhesive sheet having a low FN1 and a high FN30 is easily obtained.
In addition, when the said adhesive sheet is a form of the single-sided adhesive sheet with a support which has a support body on B layer, the normal adhesive force BN1 by the side of B layer bonds a release liner instead of a support body to the said B layer. It can be measured by attaching a PET film to the A layer side of the pressure-sensitive adhesive layer and backing it, peeling off the release liner, and attaching the exposed B layer to the adherend.

<Application>
The pressure-sensitive adhesive sheet disclosed here is a mode in which, for example, various portable devices (portable devices), automobiles, home appliances, and the like are affixed to members that make use of the feature of having both good reworkability and high adhesive strength. Thus, it can be used for applications such as fixing, joining, molding, decoration, protection and support of the member. The material constituting at least the surface of the member is, for example, glass such as alkali glass plate or non-alkali glass; metal material such as stainless steel (SUS) or aluminum; ceramic material such as alumina or silica; acrylic resin, ABS resin, Resin materials such as polycarbonate resin and polystyrene resin; The pressure-sensitive adhesive sheet disclosed herein is a coating surface with a paint such as acrylic, polyester, alkyd, melamine, urethane, acid epoxy cross-linked, or a composite system thereof (for example, acrylic melamine, alkyd melamine). Alternatively, it may be attached to a plated surface such as a galvanized steel sheet. The peeling force increasing action by the peeling force increasing agent supplied from the B layer can be effectively exhibited, for example, in a pressure-sensitive adhesive sheet attached to an adherend having a hydroxyl group on the surface. Preferable examples of such an adherend include inorganic materials such as glass as described above, the ceramic material, and the metal material. The pressure-sensitive adhesive sheet disclosed herein includes, for example, a member having at least a part of its surface made of such a material and the pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet is bonded to the surface of the member. It may be a constituent element of a member with an adhesive sheet.

An example of a preferred application is an optical application. More specifically, for example, it is disclosed here as an optical pressure-sensitive adhesive sheet used for bonding optical members (for optical member bonding) or for manufacturing products using the optical members (optical products). An adhesive sheet to be used can be preferably used.

The optical member is a member having optical characteristics (for example, polarization, light refraction, light scattering, light reflection, light transmission, light absorption, light diffraction, optical rotation, visibility, etc.). Say. Although it will not specifically limit if it is a member which has an optical characteristic as said optical member, For example, it is used for the members which comprise apparatuses (optical apparatus), such as a display apparatus (image display apparatus) and an input device, or these apparatuses. For example, a polarizing plate, a wave plate, a retardation plate, an optical compensation film, a brightness enhancement film, a light guide plate, a reflection film, an antireflection film, a hard coat (HC) film, an impact absorption film, an antifouling film, Photochromic film, light control film, transparent conductive film (ITO film), design film, decorative film, surface protection plate, prism, lens, color filter, transparent substrate, and members on which these are laminated (collectively named May be referred to as “functional films”). In addition, said "plate" and "film" shall include forms, such as plate shape, film shape, and sheet shape, respectively, for example, "polarizing film" shall include "polarizing plate", "polarizing sheet", etc. .

Examples of the display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), and electronic paper. Moreover, a touch panel etc. are mentioned as said input device.

The optical member is not particularly limited, and examples thereof include members made of glass, acrylic resin, polycarbonate, polyethylene terephthalate, metal thin films, etc. (for example, sheet-like, film-like, and plate-like members). Note that the “optical member” in this specification includes a member (design film, decorative film, surface protective film, or the like) that plays a role of decoration or protection while maintaining the visibility of the display device or the input device.

The mode of bonding the optical member using the pressure-sensitive adhesive sheet disclosed herein is not particularly limited. For example, (1) the mode of bonding the optical members to each other via the pressure-sensitive adhesive sheet disclosed herein, or (2 ) The optical member may be bonded to a member other than the optical member via the adhesive sheet disclosed herein, or (3) the adhesive sheet disclosed herein includes an optical member, The adhesive sheet may be bonded to an optical member or a member other than the optical member. In the above aspect (3), the pressure-sensitive adhesive sheet including the optical member may be, for example, a pressure-sensitive adhesive sheet whose support is an optical member (for example, an optical film). Thus, the adhesive sheet of the form containing an optical member as a support can also be grasped as an adhesive optical member (for example, an adhesive optical film). Moreover, when the pressure-sensitive adhesive sheet disclosed herein is a pressure-sensitive adhesive sheet having a support, and the functional film is used as the support, the pressure-sensitive adhesive sheet disclosed herein is a functional film. It can also be grasped as an “adhesive functional film” having an adhesive layer disclosed herein on at least one side.

<Peeling method>
Moreover, according to this specification, the method of peeling the adhesive sheet affixed on the to-be-adhered body from this to-be-adhered body is provided. In the method, the aqueous liquid is present at the interface between the adherend and the pressure-sensitive adhesive sheet at the peeling front of the pressure-sensitive adhesive sheet from the adherend, and the movement of the water-based liquid follows the movement of the peeling front. A water peeling step of peeling the pressure-sensitive adhesive sheet from the adherend while advancing to the interface may be included. Here, the peeling front refers to a position where the pressure-sensitive adhesive sheet starts to separate from the adherend when the pressure-sensitive adhesive sheet is peeled off from the adherend. According to the water peeling step, the adhesive sheet can be peeled from the adherend by effectively using the aqueous liquid. The said peeling method can be preferably implemented in the aspect which peels one of the adhesive sheets disclosed here from a to-be-adhered body, for example.

As the aqueous liquid used in the peeling method, water or a mixed solvent containing water as a main component and a small amount of additives as required can be used. As a solvent other than water constituting the mixed solvent, a lower alcohol (for example, ethyl alcohol) or a lower ketone (for example, acetone) that can be uniformly mixed with water can be used. A known surfactant or the like can be used as the additive. From the viewpoint of avoiding contamination of the adherend, in some embodiments, an aqueous liquid substantially free of additives may be preferably used. From the viewpoint of environmental hygiene, it is particularly preferable to use water as the aqueous liquid. The water is not particularly limited, and for example, distilled water, ion-exchanged water, tap water, or the like can be used in consideration of purity and availability required depending on the application.

In some embodiments, the peeling method supplies an aqueous liquid onto the adherend near the outer edge of the pressure-sensitive adhesive sheet attached to the adherend, for example, similarly to the measurement of the water peeling force FW described above. After allowing the aqueous liquid to enter the interface between the pressure-sensitive adhesive sheet and the adherend from the outer edge of the pressure-sensitive adhesive sheet, the aqueous liquid supplied onto the adherend before starting the peeling is not performed. This can be preferably carried out in such a manner that the peeling of the pressure-sensitive adhesive sheet proceeds using only the liquid. In the middle of the water stripping step, if the water entering the interface between the pressure-sensitive adhesive sheet and the adherend follows the movement of the stripping front is exhausted in the middle, intermittently after the start of the water stripping step or Additional water may be continuously supplied. For example, when the adherend has water absorption, or when aqueous liquid tends to remain on the adherend surface or adhesive surface after peeling, an embodiment in which water is additionally supplied after the start of the water peeling step is preferably employed. obtain.

The amount of the aqueous liquid supplied before the start of peeling is not particularly limited as long as the aqueous liquid can be introduced into the interface between the pressure-sensitive adhesive sheet and the adherend from the outside of the adhesive sheet sticking range. The amount of the aqueous liquid may be, for example, 5 μl or more, usually 10 μl or more, and may be 20 μl or more. Moreover, there is no restriction | limiting in particular about the upper limit of the quantity of the said aqueous liquid. In some embodiments, from the viewpoint of improving workability, the amount of the aqueous liquid may be, for example, 10 ml or less, 5 ml or less, 1 ml or less, 0.5 ml or less, 0.1 ml or less. It may be 0.05 ml or less. By reducing the amount of the aqueous liquid, the operation of removing the aqueous liquid by drying, wiping, or the like after the pressure-sensitive adhesive sheet is peeled off can be omitted or simplified.

The operation of causing the aqueous liquid to enter the interface between the pressure-sensitive adhesive sheet and the adherend from the outer edge of the pressure-sensitive adhesive sheet at the start of peeling is performed by, for example, inserting a tip of a jig such as a cutter knife or a needle into the interface at the outer edge of the pressure-sensitive adhesive sheet. Inserting, scratching and lifting the outer edge of the adhesive sheet with scissors or nails, etc., sticking a strong adhesive tape or sucker to the back surface near the outer edge of the adhesive sheet and lifting the edge of the adhesive sheet, etc. It can be carried out. Thus, by forcing the aqueous liquid to enter the interface from the outer edge of the pressure-sensitive adhesive sheet, it is possible to efficiently form a state in which the water-based liquid exists at the interface between the adherend and the pressure-sensitive adhesive sheet. In addition, it is preferable to achieve both good water releasability after an operation for forcibly entering an aqueous liquid into the interface and creating a trigger for separation, and high water resistance reliability when such operation is not performed. Can do.

The pressure-sensitive adhesive sheet to be peeled by the peeling method includes a pressure-sensitive adhesive layer, and among the pressure-sensitive adhesive layers, at least the layer A constituting the surface on the adherend side is composed of a pressure-sensitive adhesive containing a water-affinity agent. preferable. The pressure-sensitive adhesive sheet is preferably, for example, any pressure-sensitive adhesive sheet disclosed herein. Therefore, the said peeling method is suitable as a peeling method of one of the adhesive sheets disclosed here.

The water stripping process according to some embodiments can be preferably performed in a mode in which the stripping front is moved at a speed of 10 mm / min or more. Moving the peeling front at a speed of 10 mm / min or more corresponds to peeling the pressure-sensitive adhesive sheet at a tensile speed of 20 mm / min or more under the condition of a peeling angle of 180 degrees, for example. The speed at which the peeling front is moved may be, for example, 25 mm / min or more, 50 mm / min or more, 150 mm / min or more, 300 mm / min or more, or 500 mm / min or more. According to the peeling method disclosed herein, the pressure-sensitive adhesive sheet is peeled off from the adherend while allowing the aqueous liquid to enter the interface. Water releasability can be exhibited. The upper limit of the speed at which the peeling front is moved is not particularly limited. The speed at which the peeling front is moved can be, for example, 1000 mm / min or less.

The peeling method disclosed here is carried out, for example, in such a manner that the peeling area of the pressure-sensitive adhesive sheet per 10 μl volume of the aqueous liquid (for example, water) used in the method is, for example, 50 cm ² or more, preferably 100 cm ² or more. be able to.

The peeling method disclosed herein can be preferably applied to peeling of a pressure-sensitive adhesive sheet attached to a non-water-absorbing smooth surface such as a glass plate, a metal plate, a resin plate, or the like. Moreover, the peeling method disclosed here can be preferably utilized as a method of peeling an adhesive sheet from one of the optical members described above. Especially, it is suitable as a method of peeling the adhesive sheet affixed on glass plates, such as alkali glass and an alkali free glass.

Note that the matters disclosed by this specification include the following.
(1) An adhesive sheet having an adhesive layer, wherein the adhesive layer has an adhesive surface that can be attached to an adherend,
The adhesive sheet in which the peeling force raising agent supply part which supplies a peeling force raising agent to the said surface part is provided in the location separated from the said adhesion surface via the surface part by the side of the said adhesion surface.
(2) The pressure-sensitive adhesive sheet according to (1), wherein the peel strength increasing agent is contained in the supply unit in a free form.
(3) The pressure-sensitive adhesive sheet according to (1) or (2), wherein the peeling force increasing agent includes a functional group X and a functional group Y in one molecule.
(4) The functional group X is a group that reacts with a hydroxyl group that may be present on the adherend surface or a precursor thereof, and the functional group Y is a group that reacts with a functional group y contained in the surface portion. The pressure-sensitive adhesive sheet according to (3) above.
(5) The pressure-sensitive adhesive sheet according to (3) or (4), wherein the functional group X is an alkoxysilyl group.
(6) The functional group Y is any one of the above (3) to (5), which is at least one selected from the group consisting of an epoxy group, an amino group, an isocyanate group, and a (meth) acryloyl group. Adhesive sheet.

(7) The pressure-sensitive adhesive layer includes a layer A constituting the pressure-sensitive adhesive surface and a layer B disposed on the back side of the layer A,
The pressure-sensitive adhesive sheet according to any one of the above (1) to (6), wherein the B layer includes the peeling force increasing agent supplying section.
(8) The following conditions:
The A layer does not contain a peel strength raising agent; and
The layer A contains a peeling force increasing agent, and the concentration C _B [wt%] of the peeling force increasing agent in the B layer is higher than the concentration C _A [wt%] of the peeling force increasing agent in the A layer;
The pressure-sensitive adhesive sheet according to (7), which satisfies any of the above.
(9) The glass transition temperature Tg _A of the base polymer of the A layer is −10 ° C. or lower,
The pressure-sensitive adhesive sheet according to (7) or (8), wherein the glass transition temperature Tg _B of the base polymer of the B layer is 10 ° C. or more higher than the glass transition temperature Tg _A of the base polymer of the A layer.
(10) The pressure-sensitive adhesive sheet according to any one of (7) to (9), wherein each of the A layer and the B layer is an acrylic pressure-sensitive adhesive layer.
(11) The A layer is an acrylic pressure-sensitive adhesive layer formed from a water-dispersed pressure-sensitive adhesive composition,
The pressure-sensitive adhesive sheet according to any one of (7) to (10), wherein the layer B is an acrylic pressure-sensitive adhesive layer formed from a photocurable pressure-sensitive adhesive composition or a solvent-type pressure-sensitive adhesive composition.
(12) The pressure-sensitive adhesive sheet according to any one of (7) to (11), wherein the layer A contains a water-affinity agent.
(13) The water affinity agent is at least one selected from the group consisting of an anionic surfactant, a nonionic surfactant, a cationic surfactant, a water-soluble plasticizer, and a water-soluble polymer. The pressure-sensitive adhesive sheet according to 12).
(14) The content of the water affinity agent is 0.2 to 20 parts by weight with respect to 100 parts by weight of the monomer component constituting the layer A, The pressure-sensitive adhesive sheet described in 1.
(15) The pressure-sensitive adhesive sheet according to any one of (7) to (14), wherein the thickness of the A layer is 10 μm or more and 50 μm or less.
(16) The pressure-sensitive adhesive sheet according to any one of (7) to (15), wherein the thickness of the B layer is 2 times or more, 3 times or more, or 5 times or more the thickness of the A layer.
(17) The pressure-sensitive adhesive sheet according to any one of (7) to (16), wherein the thickness of the B layer is 20 times or less, 15 times or less, or 10 times or less the thickness of the A layer.
(18) The pressure-sensitive adhesive sheet according to any one of (1) to (17), wherein the pressure-sensitive adhesive constituting the surface portion is water-insoluble and water-swellable.
(19) The pressure-sensitive adhesive sheet according to any one of (1) to (18), wherein the pressure-sensitive adhesive layer has a thickness of 10 μm or more and 500 μm or less.

(20) A normal peeling force FN1 measured under conditions of a tensile speed of 60 mm / min and a peeling angle of 180 degrees after 1 day at room temperature after affixing the adhesive surface to an adherend is 2.8 N / cm or less, and (1) to (1) to (1) to (1) above, wherein a normal peeling force FN30 measured under conditions of a tensile speed of 60 mm / min and a peeling angle of 180 degrees is 30 N / cm or more after 30 days at room temperature after the adhesive surface is attached to the adherend. The pressure-sensitive adhesive sheet according to any one of 19).
(21) The pressure-sensitive adhesive sheet according to any one of (1) to (20), wherein an increase rate of the normal peeling force FN30 with respect to the normal peeling force FN1 is 20% or more.
(22) The above normal peeling force FN1 is 2.8 N / cm or less, and the adhesive surface is attached to the adherend, and after 30 days at room temperature and after heat treatment at 60 ° C. for 1 day, the tensile rate is 60 mm / min. The pressure-sensitive adhesive sheet according to any one of the above (1) to (21), wherein the normal peeling force FNh30 measured at an angle of 180 degrees is 3.0 N / cm or more.
(23) The pressure-sensitive adhesive sheet according to any one of (1) to (22), wherein an increase rate of the normal peeling force FNh30 with respect to the normal peeling force FN1 is 20% or more.
(24) After 1 day at room temperature after pasting the adhesive surface to the adherend, a drop of water is dropped onto the adherend, and the water enters one end of the interface between the adhesive layer and the adherend. Then, the water peeling force FW1 measured under the conditions of a tensile speed of 60 mm / min and a peeling angle of 180 degrees without supplying new water is less than 1.0 N / cm, (1) to (23 ) The pressure-sensitive adhesive sheet according to any one of the above.
(25) The adhesive surface is attached to the adherend, and after 30 days at room temperature, one drop of water is dropped on the adherend, and the water enters one end of the interface between the adhesive layer and the adherend. After that, the water peeling force FW30 measured under the conditions of a tensile speed of 60 mm / min and a peeling angle of 180 degrees without supplying new water is 2.0 N / cm or more, (1) to (24 ) The pressure-sensitive adhesive sheet according to any one of the above.

(26) A member with a pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive sheet according to any one of the above (1) to (25) and a member bonded to the one surface of the pressure-sensitive adhesive layer.
(27) A method for peeling an adhesive sheet attached to an adherend,
In the state where an aqueous liquid is present at the interface between the adherend and the pressure-sensitive adhesive sheet at the peeling front of the pressure-sensitive adhesive sheet from the adherend, the movement of the peeling front follows the movement of the water-based liquid to the interface. A peeling method including a water peeling step of peeling the pressure-sensitive adhesive sheet from the adherend while advancing.
(28) The peeling method according to (27), wherein the pressure-sensitive adhesive sheet is the pressure-sensitive adhesive sheet according to any one of (1) to (25).
(29) The peeling method according to (27) or (28), wherein in the water peeling step, the peeling front is moved at a speed of 10 mm / min or more.

Hereinafter, some examples relating to the present invention will be described. However, the present invention is not intended to be limited to the examples shown in the examples. In the following description, “parts” and “%” are based on weight unless otherwise specified.

<Preparation of pressure-sensitive adhesive composition>
(Adhesive composition A-1)
2-ethylhexyl acrylate (2EHA) 85 parts, methyl acrylate (MA) 13 parts, acrylic acid (AA) 1.2 parts, methacrylic acid (MAA) 0.8 parts, 3-methacryloxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.) 0.02 part of KBM-503), 0.05 part of t-dodecyl mercaptan as a chain transfer agent and 2.0 parts of an emulsifier (Laomul E-118B made by Kao Corporation) were mixed in 100 parts of ion-exchanged water. Then, an aqueous emulsion (monomer emulsion) of the monomer mixture was prepared by emulsifying.
The monomer emulsion was placed in a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer, and a stirring device, and stirred at room temperature for 1 hour or more while introducing nitrogen gas. Next, the temperature of the system was raised to 60 ° C., and 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (VA-057 manufactured by Wako Pure Chemical Industries, Ltd.) was used as a polymerization initiator. ) 0.1 part was added and reacted at 60 ° C. for 6 hours to obtain an aqueous dispersion of an acrylic polymer.
After cooling the system to room temperature, tackifying resin emulsion (Arakawa Chemical Co., Superester E-865NT, polymerized rosin ester aqueous dispersion with a softening point of 160 ° C.) per 100 parts of the acrylic polymer contained in the aqueous dispersion. Was added in a solid content of 30 parts. Furthermore, using 10% aqueous ammonia as a pH adjuster and polyacrylic acid (an aqueous solution with a non-volatile content of 36%) as a thickener, adjusting the pH to about 7.5 and the viscosity to about 9 Pa · s. Thus, an emulsion-type pressure-sensitive adhesive composition A-1 was prepared.

(Adhesive composition B-1)
In a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, 64.5 parts of n-butyl acrylate (BA), 6 parts of cyclohexyl acrylate (CHA), N-vinyl-2-pyrrolidone ( NVP) 9.6 parts, isostearyl acrylate (iSTA) 5 parts and 4-hydroxybutyl acrylate (4HBA) 14.9 parts, α-thioglycerol 0.07 parts as a chain transfer agent, and ethyl acetate 122 parts as a polymerization solvent. Charged 0.22 parts 2,2'-azobisisobutyronitrile (AIBN) as a thermal polymerization initiator and solution polymerization in a nitrogen atmosphere contains an acrylic polymer with a Mw of 600,000 A solution was obtained.

3-glycidoxypropyltrimethoxysilane (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent per 100 parts of the monomer component used for the preparation of the solution was added to the solution obtained above. .33 parts, isocyanate-based crosslinking agent (trimethylolpropane / xylylene diisocyanate adduct (Mitsui Chemicals, Takenate 110N, solid concentration 75% by mass) on the basis of solid content, 0.09 parts, acrylic oligomer 0. 4 parts, 0.02 part of dioctyltin dilaurate (manufactured by Tokyo Fine Chemical Co., Ltd., OL1) as a crosslinking catalyst, 3 parts of acetylacetone as a crosslinking retarder, 2.7 parts of dipentaerythritol hexaacrylate (DPHA) as a polyfunctional monomer , Irgacure 184 (Cibas) as a photopolymerization initiator Shall tee Chemicals Inc.) 0.22 parts was added thereto to prepare a pressure-sensitive adhesive composition B-1 was uniformly mixed.

As said acrylic oligomer, what was synthesize | combined with the following method was used.
[Synthesis of acrylic oligomer]
100 parts of toluene, 60 parts of dicyclopentanyl methacrylate (DCPMA) (trade name: FA-513M, manufactured by Hitachi Chemical Co., Ltd.), 40 parts of methyl methacrylate (MMA), and α-thioglycerol 3.5 as a chain transfer agent Was put into a four-necked flask. Then, after stirring at 70 ° C. under a nitrogen atmosphere for 1 hour, 0.2 part of AIBN was added as a thermal polymerization initiator and reacted at 70 ° C. for 2 hours, followed by reaction at 80 ° C. for 2 hours. Thereafter, the reaction solution was put into a temperature atmosphere of 130 ° C., and toluene, chain transfer agent, and unreacted monomer were removed by drying to obtain a solid acrylic oligomer. The acrylic oligomer had a Tg of 144 ° C. and an Mw of 4300.

(Adhesive composition B-2)
A pressure-sensitive adhesive composition B-2 was prepared in the same manner as the pressure-sensitive adhesive composition B-1, except that the amount of 3-glycidoxypropyltrimethoxysilane used was 0.25 parts per 100 parts of the monomer component. did.

(Adhesive composition B-3)
A pressure-sensitive adhesive composition B-3 was prepared in the same manner as the pressure-sensitive adhesive composition B-1, except that the amount of 3-glycidoxypropyltrimethoxysilane used was 0.08 parts per 100 parts of the monomer component. did.

(Adhesive composition B-4)
A pressure-sensitive adhesive composition B-4 was prepared in the same manner as the pressure-sensitive adhesive composition B-1, except that 3-glycidoxypropyltrimethoxysilane was not used.

<Production of adhesive sheet>
(Example 1)
The pressure-sensitive adhesive composition B-1 was applied to a 38 μm-thick release film R1 (Mitsubishi Resin Co., Ltd., MRF # 38) having a release surface on one side of the polyester film, dried at 135 ° C. for 2 minutes, A pressure-sensitive adhesive layer B1 having a thickness of 130 μm was formed. A laminate sheet in which a PET film (support), an adhesive layer B1, and a release film R1 are laminated in this order by laminating a corona-treated polyethylene terephthalate (PET) film having a thickness of 75 μm to the adhesive layer B1. Got.
Adhesive composition A-1 was applied to release film R1 (Mitsubishi Resin Co., Ltd., MRF # 38) and dried at 120 ° C. for 3 minutes to form an adhesive layer A1 having a thickness of 20 μm. The release film R1 covering the pressure-sensitive adhesive layer B1 of the laminated sheet is peeled off, and the pressure-sensitive adhesive layer A1 is bonded thereto, whereby the pressure-sensitive adhesive layer B1 and the pressure-sensitive adhesive layer A1 are placed in this order on the PET film (support). A pressure-sensitive adhesive layer having a two-layer structure laminated in direct contact was formed. The surface on the A1 layer side of this pressure-sensitive adhesive sheet is protected from the release film R1 used for forming the pressure-sensitive adhesive layer A1.

(Examples 2 to 4)
A pressure-sensitive adhesive sheet according to each example was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive compositions B-2 to B-4 were used in place of the pressure-sensitive adhesive composition B-1.

(Example 5)
The pressure-sensitive adhesive composition B-1 was applied to the release film R1 (Mitsubishi Resin Co., Ltd., MRF # 38) and dried at 135 ° C. for 2 minutes to form a pressure-sensitive adhesive layer B5 having a thickness of 150 μm. By laminating a 75 μm thick polyethylene terephthalate (PET) film treated with corona to the pressure-sensitive adhesive layer B5, the PET film (support), the pressure-sensitive adhesive layer B5 and the release film R1 are laminated in this order. An adhesive sheet was obtained.

<Performance evaluation>
About the obtained adhesive sheet, the normal peeling force and the water peeling force were measured according to the method demonstrated above. The results are shown in Table 1. Further, the rate of increase in peel strength and the rate of decrease in water peel adhesive strength were calculated based on the measurement results, and the results are shown in Table 2.
Here, the adhesive sheet was attached to the adherend by the following method. That is, each pressure-sensitive adhesive sheet was cut into a rectangular shape having a width of 10 mm and a length of 120 mm to prepare a test piece, and an alkali glass plate (manufactured by Matsunami Glass Industrial Co., Ltd., thickness 1.35 mm, blue plate edge polishing) Product) with a hand roller. This sample for evaluation was put into an autoclave and treated for 15 minutes under conditions of a pressure of 5 atm and a temperature of 50 ° C. The sample for evaluation taken out from the autoclave was irradiated with light through the alkali glass plate in an environment of 23 ° C. and 50% RH. More specifically, the pressure-sensitive adhesive layers B1 to B4 included in the pressure-sensitive adhesive sheet according to each example were photocured by irradiating ultraviolet rays with an integrated light quantity of 3000 mJ / cm ² using a high-pressure mercury lamp (300 mW / cm ² ). .

As shown in Table 1, each of the pressure-sensitive adhesive sheets of Examples 1 to 3 having a two-layered pressure-sensitive adhesive layer in which a layer B containing a peeling force increasing agent is laminated on the back surface of the layer A constituting the pressure-sensitive adhesive surface. During the period from the pasting to the adherend to at least one day later, the peel force was usually suppressed to 2.8 N / cm or less, and during this period, rework was easily possible. Further, these adhesive sheets usually had a peel force that greatly exceeded 3.0 N / cm after 30 days from application to the adherend, and could be firmly bonded to the adherend. In the pressure-sensitive adhesive sheets of Examples 1 to 3, the water peeling force was suppressed to less than 1.0 N / cm at least from one day after application to the adherend. That is, in these pressure-sensitive adhesive sheets, the load on the adherend could be remarkably reduced by performing a peeling operation using a small amount of water. These pressure-sensitive adhesive sheets were able to improve the water-reliability of the joints after 30 days from application to the adherend, with the water peeling force significantly exceeding 2.0 N / cm. Further, when the normal peel force FNh30 after heat treatment at 60 ° C. for 30 days after 30 days was measured according to the above method, 9.7 N / cm in Example 1 (peeling force increase rate 288%), 8 in Example 2 It was 9.9 N / cm (456%) and in Example 3 it was 8.2 N / cm (486%), and it was confirmed that the peeling force could be further improved by heat treatment. In the measurement of the normal peel force and the water peel force, no adhesive residue was formed on the adherend when the peel force was about 3.0 N / cm or less. Although specific numerical values are not shown, each of the pressure-sensitive adhesive layers formed from the pressure-sensitive adhesive compositions A-1 and B-1 to B-4 is water-insoluble and water-swellable. It has been confirmed.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

1, 2 Adhesive sheet 10 Adhesive layer 10A One surface (adhesive surface)
10B The other surface (back)
20 support body 20A 1st surface 20B 2nd surface (back surface)
30 Release liner 40 Peeling force increasing agent-containing layer (peeling force increasing agent supply part)
50 Adhesive sheet with release liner 70 Member 110 Adhesive layer 110A One surface (adhesive surface)
112 A layer (surface part)
114 B layer (peeling power raising agent supply part)
200 Member with adhesive sheet

Claims (12)

1. The pressure-sensitive adhesive sheet has a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer has a pressure-sensitive adhesive surface that can be attached to an adherend.
   The adhesive sheet in which the peeling force raising agent supply part which supplies a peeling force raising agent to the said surface part is provided in the location separated from the said adhesion surface through the surface part by the side of the said adhesion surface.
2. The peeling force increasing agent contains a functional group X and a functional group Y in one molecule,
   The functional group X is a group that reacts with a hydroxyl group that may be present on the adherend surface or a precursor thereof.
   The functional group Y is a group that reacts with the functional group y contained in the surface portion,
   The pressure-sensitive adhesive sheet according to claim 1, wherein the peeling force increasing agent is contained in the supply unit in a free form.
3. The pressure-sensitive adhesive sheet according to claim 2, wherein the functional group X is an alkoxysilyl group.
4. The pressure-sensitive adhesive layer includes an A layer constituting the pressure-sensitive adhesive surface and a B layer disposed on the back side of the A layer,
   The said B layer is an adhesive sheet as described in any one of Claim 1 to 3 containing the said peeling force raising agent supply part.
5. The pressure-sensitive adhesive sheet according to claim 4, wherein the concentration C _B [wt%] of the peeling force increasing agent in the B layer is higher than the concentration C _A [wt%] of the peeling force increasing agent in the A layer.
6. The pressure-sensitive adhesive sheet according to claim 4 or 5, wherein the thickness of the A layer is 2 µm or more and 100 µm or less.
7. The adhesive surface is attached to an adherend, and a normal peeling force FN1 measured under conditions of a tensile speed of 60 mm / min and a peeling angle of 180 degrees one day after room temperature is 2.8 N / cm or less, and the adhesive surface is The conventional peeling force FN30 measured under conditions of a tensile speed of 60 mm / min and a peeling angle of 180 degrees after 30 days at room temperature after being attached to an adherend is 3.0 N / cm or more, and any one of claims 1 to 6. The pressure-sensitive adhesive sheet according to item.
8. The adhesive surface is affixed to the adherend against the normal peel force FN1 measured at a tensile speed of 60 mm / min and a peel angle of 180 degrees after 1 day at room temperature. The pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein an increase rate of the normal peeling force FN30 measured under conditions of a tensile speed of 60 mm / min and a peeling angle of 180 degrees after 30 days at room temperature is 20% or more.
9. The adhesive surface is attached to an adherend, and after 30 days at room temperature, a normal peeling force FN1 measured under conditions of a tensile speed of 60 mm / min and a peeling angle of 180 degrees is 2.8 N / cm or less, and the adhesive surface is Affixed to the adherend after 30 days at room temperature, and after heat treatment at 60 ° C. for 1 day, the normal peel force FNh30 measured under conditions of a tensile speed of 60 mm / min and a peel angle of 180 degrees is 3.0 N / cm or more. The pressure-sensitive adhesive sheet according to any one of claims 1 to 8.
10. The adhesive surface is affixed to the adherend with respect to the normal peeling force FN1 measured at a tensile speed of 60 mm / min and a peeling angle of 180 degrees after 30 days of room temperature. The increase rate of the normal peeling force FNh30 measured under the conditions of a tensile rate of 60 mm / min and a peeling angle of 180 degrees after 30 days of room temperature and 1 day of heat treatment at 60 ° C. is 20% or more. The pressure-sensitive adhesive sheet according to claim 1.
11. After 1 day at room temperature after affixing the adhesive surface to the adherend, after dropping one drop of water on the adherend and allowing the water to enter one end of the interface between the adhesive layer and the adherend The water peeling force FW1 measured under the conditions of a tensile speed of 60 mm / min and a peeling angle of 180 degrees without supplying new water is less than 1.0 N / cm. The pressure-sensitive adhesive sheet described in 1.
12. After adhering the adhesive surface to the adherend and after 30 days at room temperature, dropping one drop of water onto the adherend and allowing the water to enter one end of the interface between the adhesive layer and the adherend. The water peeling force FW30 measured under the conditions of a tensile speed of 60 mm / min and a peeling angle of 180 degrees without supplying new water is 2.0 N / cm or more. The pressure-sensitive adhesive sheet described in 1.
    
    

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