TW201938734A - Temperature sensitive adhesive sheet and laminate body wherein the temperature-sensitive adhesive sheet is excellent in operability even when it is applied to a flexible device - Google Patents

Abstract

The object of the present invention is to provide a temperature-sensitive adhesive sheet which is excellent in operability even when it is applied to a flexible device, and a laminate body using the temperature-sensitive adhesive sheet. To solve the problem, a temperature-sensitive adhesive sheet 1 is provided, which is a temperature-sensitive adhesive sheet 1 at least including an adhesive layer 11, wherein the glass adhesion force of the temperature-sensitive adhesive at -20 DEG C is less than 1.5 N/25 mm, the glass adhesion force at 80 DEG C is 2.0 N/25 mm or more, and the storage modulus of the adhesive layer 11 at -20 DEG C is 1 MPa or more and 500 MPa or less. Furthermore, the ratio of the glass adhesion force of the temperature-sensitive adhesive at -20 DEG C to the glass adhesion force at 23 DEG C is 1% or more and 40% or less, and the ratio of the glass adhesion force of the temperature-sensitive adhesive at 80 DEG C to the glass adhesion force at 23 DEG C is 10% or more and 300% or less.

Description

Temperature-sensitive adhesive sheet and laminate

The invention relates to a temperature-sensitive adhesive sheet suitable for fixing and peeling of a workpiece and a laminated body using the temperature-sensitive adhesive sheet.

In a device such as an optical member or an electronic member to be processed (workpiece), the device is fixed to a substrate (base) through an adhesive layer of an adhesive sheet in steps such as processing, assembly (layering), and inspection. ). Then, after the step is completed, the work is peeled from the substrate.

As an adhesive used in the above-mentioned adhesive sheet, for example, Patent Document 1 discloses a temperature-sensitive adhesive containing a side-chain crystalline polymer, which is obtained by adding a metal chelate compound to octadecyl acrylate and acrylic acid A copolymer obtained by polymerizing methyl ester and acrylic acid, or a cross-linked polymer obtained by subjecting a copolymer obtained by polymerizing dimethyl acrylate, methyl acrylate, and acrylic acid to a crosslinking reaction.

Further, Patent Document 2 discloses a temperature-sensitive adhesive containing a (meth) acrylic acid ester having a linear alkyl group having 16 to 22 and a (meth) acrylic acid having an alkyl group having 1 to 6 carbon atoms. An ester, an ethylenically unsaturated monomer having a carboxyl group or a hydroxyl group, and a copolymer obtained by polymerizing a reactive fluorine compound, a side chain crystalline polymer crosslinked using a metal chelate compound, and an adhesion-imparting agent.

When the temperature-sensitive adhesive disclosed in Patent Document 1 is used, the adherend can be fixed by the adhesive force exerted by the adhesive under a high-temperature environment. On the other hand, the adhesive force can be reduced by cooling and the adhesive Adhesive is peeling. Furthermore, when the temperature-sensitive adhesive disclosed in Patent Document 2 is used, the adherend can be fixed by the adhesive force exerted by the adhesive at the ambient temperature in a normal step, and on the other hand, it can be cooled by cooling The adhesive force is reduced and the adherend can be peeled off.
[Prior technical literature]
[Patent Literature]

[Patent Document 1] Japanese Patent No. 5600604
[Patent Document 2] Japanese Patent No. 6100932

[Questions to be Solved by the Invention]

Previously, the above devices were mostly hard objects, but in recent years, flexible devices have appeared. For example, in terms of optical components, the dynamics from a rigid liquid crystal device to a flexible organic light-emitting diode (OLED) device have recently become active. Therefore, even as an adhesive sheet, it is necessary to support such a flexible device.

However, when the temperature-sensitive adhesives disclosed in Patent Documents 1 and 2 are applied to a flexible device as described above, it is difficult to say that they have sufficient handling properties for fixing and peeling.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a temperature-sensitive adhesive sheet excellent in operability even when applied to a flexible device, and a laminated body using the temperature-sensitive adhesive sheet.
[Means to solve the problem]

In order to achieve the above object, the first aspect of the present invention provides a temperature-sensitive adhesive sheet, which is a temperature-sensitive adhesive sheet including at least an adhesive layer, and is characterized in that the adhesive force to glass at -20 ° C is less than 1.5N / 25mm The adhesive force to glass at 80 ° C is 2.0N / 25mm or more, and the storage modulus of the aforementioned adhesive layer at -20 ° C is 1 MPa to 500 MPa (Invention 1).

According to the above-mentioned invention (Invention 1), even when this temperature-sensitive adhesive sheet is applied to a flexible device, it has excellent operability with respect to fixing and peeling. That is, in the steps of normal temperature and high temperature, the workpiece can be firmly fixed to the substrate, and this step can be performed without problems. In addition, when the adhesive layer is cooled to a low temperature, the adhesive force of the adhesive layer is reduced, whereby the workpiece can be easily peeled from the substrate.

In the above invention (Invention 1), the ratio of the adhesion to glass at -20 ° C to the adhesion to glass at 23 ° C is preferably 1% or more and 40% or less (Invention 2).

In the above invention (Inventions 1, 2), the ratio of the adhesion force to glass at 80 ° C to the adhesion force to glass at 23 ° C is preferably 10% or more and 300% or less (Invention 3).

In the above invention (Inventions 1 to 3), the storage modulus of the aforementioned adhesive layer at 80 ° C is preferably 0.01 MPa or more and 1 MPa or less (Invention 4).

In the above inventions (Inventions 1 to 4), it is preferable that the adhesive layer is composed of an adhesive containing a polyrotaxane compound (Invention 5).

In the above invention (Invention 5), it is preferable that the aforementioned adhesive is an adhesive composition containing a (meth) acrylate polymer (A), a crosslinking agent (B), and a polyrotaxane compound (C). Formation (Invention 6).

In the above invention (Invention 6), it is preferable that the aforementioned (meth) acrylate polymer (A) contains a monomer having a carboxyl group in the molecule as a monomer unit constituting the polymer (Invention 7).

In the above inventions (Inventions 6, 7), it is preferable that the crosslinking agent (B) is a metal chelate-based crosslinking agent (Invention 8).

In the above-mentioned invention (Inventions 1 to 8), the temperature-sensitive adhesive sheet is preferably used in the step to fix the workpiece to the substrate through the adhesive layer, and after the step is completed, the workpiece is peeled from the adhesive layer. Use (Invention 9).

In the above invention (Invention 9), the surface roughness Ra of the surface on the side of the adhesive layer of the workpiece is preferably 0.01 μm or more and 80 μm or less (Invention 10).

In the above invention (Inventions 9, 10), in the aforementioned step, the workpiece may also be heated to 40 ° C or higher and 200 ° C or lower (Invention 11).

In the above invention (Inventions 9 to 11), the workpiece may be a flexible device (Invention 12).

In the above invention (Inventions 1 to 12), it is preferable that the temperature-sensitive adhesive sheet includes two release sheets, and the adhesive layer is held by the release sheet so as to be in contact with the release surfaces of the two release sheets. (Invention 13).

A second aspect of the present invention provides a laminated body, which is formed by laminating a flexible device, the adhesive layer of the temperature-sensitive adhesive sheet (Inventions 1 to 13), and a substrate in this order (Invention 14).
[Inventive effect]

Even when the temperature-sensitive adhesive sheet of the present invention is applied to a flexible device, it has excellent operability with respect to fixing and peeling. Moreover, the laminated body of this invention is excellent in the handleability.

Hereinafter, embodiments of the present invention will be described.
The temperature-sensitive adhesive sheet according to an embodiment of the present invention includes at least an adhesive layer, and is preferably formed by laminating a release sheet on one or both sides of the adhesive layer.

The temperature-sensitive adhesive sheet of this embodiment is suitable for use in processes such as processing, assembly (layering), and inspection, and is used as an optical member of a workpiece (workpiece) through the adhesive layer of the temperature-sensitive adhesive sheet. Devices such as electronic components are fixed to the substrate. After the above steps are completed, the workpiece is peeled from the substrate. The substrate is an object for supporting and fixing a workpiece in a step, and also includes a concept such as a base.

The workpiece is not particularly limited, and a flexible device such as an optical member or an electronic member having flexibility is preferable. The workpiece is preferably a workpiece that includes a heating step (for example, a heating step of 40 ° C. or higher and 200 ° C. or lower) in the above steps. Examples of such a heating step include a metal vapor deposition step for forming a transparent electrode wiring, a resin hardening step, and the like. From these viewpoints, as the workpiece, for example, a flexible organic light emitting diode (OLED) device, a flexible liquid crystal device, and the like are preferable, and a flexible OLED device is particularly preferable.

In addition, the substrate is not particularly limited as long as the workpiece can be fixed through the adhesive layer of the temperature-sensitive adhesive sheet, and it is preferable to include a metal vapor deposition step, a resin hardening step, and the like even in the above steps. The heating step does not cause deformation or appearance change. In addition, the substrate is bonded to the workpiece through the adhesive layer of the temperature-sensitive adhesive sheet. In the above steps and the step of peeling the workpiece, the adhesive layer and the substrate must be sufficiently fixed. For example, when the surface of the substrate is rough, the adhesion between the substrate and the adhesive layer is lowered, and in some cases, a defect may occur in which the adhesive layer is peeled from the substrate. Therefore, the surface on the fixed side of the workpiece on the substrate is preferably smooth. From these viewpoints, the substrate is particularly preferably a glass substrate.

In the temperature-sensitive adhesive sheet of this embodiment, the adhesive force to glass at -20 ° C is less than 1.5N / 25mm, and the adhesive force to glass at 80 ° C is more than 2.0N / 25mm. In addition, the adhesive layer of the temperature-sensitive adhesive sheet of this embodiment has a storage modulus at -20 ° C of 1 MPa to 500 MPa. With the adhesion to glass at -20 ° C and 80 ° C and the storage modulus at -20 ° C as the above values, even when the temperature-sensitive adhesive sheet is applied to a flexible device, the operation is fixed and peeled. Sex is also excellent. Specifically, in the normal temperature and high temperature steps, the workpiece can be firmly fixed to the substrate by the adhesive force of the adhesive layer of the temperature-sensitive adhesive sheet, and this step can be performed without problems. On the other hand, when the above-mentioned adhesive layer (or workpiece ‧ substrate) is cooled to a low temperature (preferably to about -20 ° C.), the adhesive force of the adhesive layer is reduced, whereby the workpiece can be easily removed from the substrate. Peel off.

Here, the adhesive force in this specification basically refers to the adhesive force measured using the 180-degree peeling method in accordance with JIS Z0237: 2009, but the measurement sample is set to be 25 mm wide and 100 mm long. After being adhered to the adherend, it was pressurized at 0.5 MPa and 50 ° C. for 20 minutes, and then left under normal pressure, required temperature, and 50% RH conditions for 24 hours, and then measured at a peeling speed of 2.0 m / min. The "adhesive force to glass" in this specification refers to the adhesive force to soda lime glass. The method for measuring the storage modulus in this specification is shown in the test example described later.

As a workpiece to which the temperature-sensitive adhesive sheet of this embodiment is applied, it is preferable that the surface in contact with the adhesive layer of the temperature-sensitive adhesive sheet is smooth to some extent. Specifically, the surface roughness Ra of the surface on the side of the adhesive layer of the workpiece is preferably 80 μm or less, particularly preferably 40 μm or less, and further preferably 10 μm or less. In this way, when the adhesive layer and the contact surface of the workpiece are smooth to some extent, the adhesiveness when the workpiece is fixed can be more effectively exhibited.

The lower limit value of the surface roughness Ra of the surface on the side of the adhesive layer of the workpiece is not particularly limited, but it is preferably 0.01 μm or more, more preferably 0.1 μm or more, and even more preferably 1 μm or more. When the lower limit value of the surface roughness Ra is as described above, the adhesiveness when the workpiece is fixed and the easy peelability when the workpiece is peeled can be more effectively exhibited. The surface roughness Ra of the surface on the side of the adhesive layer of the workpiece is preferably larger than the surface roughness Ra of the substrate. Thereby, when the workpiece is peeled off, the workpiece can be peeled off while the adhesive layer is firmly fixed on the substrate side.

The surface roughness Ra in this specification is a value measured in accordance with JIS B0601: 2001, and is set to a cutoff value λc = 0.8 mm and an evaluation length ln = 10 mm.

From the viewpoint of the above-mentioned operability, especially the easy peelability of the workpiece, the temperature-sensitive adhesive sheet of this embodiment has an adhesive force to glass of -20 ° C, preferably 1.3N / 25mm or less, and 1.0N / Below 25mm is particularly good. The lower limit of the adhesive force to glass at -20 ° C is preferably 0.01N / 25mm or more, and 0.1N / 25mm or more from the viewpoint of peeling off the workpiece while the adhesive layer is firmly fixed on the substrate side. Extraordinary.

From the viewpoint of the above-mentioned operability, especially the fixation of the workpiece in the step, the temperature-sensitive adhesive sheet of this embodiment has an adhesive force to the glass of 2.0N / 25mm or more at 80 ° C, and preferably 2.2N / 25mm or more. Particularly preferred is 2.8N / 25mm or more. When the lower limit value of the adhesive force to glass at 80 ° C is as described above, even if the step includes a heating step, it is possible to suppress the position shift or peeling of the workpiece during the step, and the workpiece can be sufficiently fixed. On the other hand, the upper limit of the adhesion to glass at 80 ° C is not particularly limited, but is preferably 70 N / 25 mm or less, particularly preferably 40 N / 25 mm or less, and more preferably 20 N / 25 mm or less.

In addition, from the viewpoint of the above-mentioned operability, especially the fixation of the workpiece in the step, the temperature-sensitive adhesive sheet of this embodiment has an adhesive force to glass of 23 ° C, preferably 2.0N / 25mm or more, and 2.8N / 25mm or more is particularly preferable, and 3.4N / 25mm or more is more preferable. On the other hand, at the upper limit of the glass adhesion at 23 ° C, from the viewpoint of reworkability, 30N / 25mm or less is preferred, 15N / 25mm or less is particularly preferred, and 10N / 25mm or less is preferred.

In the temperature-sensitive adhesive sheet of this embodiment, the ratio of the adhesion force to glass at -20 ° C to the adhesion force to glass at 23 ° C is preferably 1% or more, particularly 5% or more, and more preferably Above 10% is preferred. When the lower limit value of the adhesion force ratio is as described above, when the workpiece is cooled to a low temperature and the workpiece is peeled off, it is possible to prevent floating and peeling at the interface between the substrate and the adhesive. The ratio of the adhesion force is preferably 40% or less, particularly preferably 35% or less, and further preferably 30% or less. When the upper limit of the ratio of the adhesion force is as described above, when cooling to a low temperature, the adhesion force is sufficiently low, and the peelability of the work is more excellent. Therefore, when the ratio of the adhesion force is within the above-mentioned range, the coexistence of the adhesiveness when the workpiece is fixed and the easy peelability of the workpiece become more excellent.

In addition, in the temperature-sensitive adhesive sheet of this embodiment, the ratio of the adhesion force to glass at 80 ° C to the adhesion force to glass at 23 ° C is preferably 10% or more, and particularly preferably 30% or more. It is more preferably 50% or more. When the lower limit value of the adhesion force ratio is as described above, in particular, even if the step includes a heating step, since the adhesion force is not excessively reduced, it is possible to prevent positional displacement and peeling of the workpiece in the step, and it is possible to change the workpiece Fully fixed. The upper limit value of the adhesion ratio is not particularly limited, but is preferably 300% or less, particularly preferably 200% or less, and further preferably 100% or less. Therefore, when the ratio of the adhesion force is within the above range, it is possible to perform both of the work fixing at a normal temperature and the work fixing at a high temperature.

The adhesion of the temperature-sensitive adhesive sheet of this embodiment to a polyethylene terephthalate (PET) film with a surface roughness Ra of 2.7 μm (very smooth surface) at -20 ° C, below 1.2N / 25mm Preferably, it is particularly preferably 1.0N / 25mm or less, and further preferably 0.8N / 25mm or less. Thereby, when the surface state of the workpiece is the same as that of the above-mentioned PET film, when the above-mentioned adhesive layer (or workpiece · substrate) is cooled to a low temperature (preferably, cooled to around -20 ° C), the workpiece can be more easily removed from the workpiece. The adhesive layer was peeled. On the other hand, the lower limit of the adhesive force is not particularly limited, but is preferably 0.01 N / 25 mm or more, particularly preferably 0.05 N / 25 mm or more, and more preferably 0.1 N / 25 mm or more.

In addition, the adhesion of the temperature-sensitive adhesive sheet of this embodiment to a PET film with a surface roughness Ra of 60 μm (the surface is relatively smooth) at -20 ° C is preferably 1.0N / 25mm or less, and 0.8N / 25mm The following are particularly preferred, and more preferably 0.6 N / 25 mm or less. Thereby, when the surface state of the workpiece is equivalent to the above-mentioned PET film, when the above-mentioned adhesive layer (or workpiece · substrate) is cooled to a low temperature (preferably cooled to around -20 ° C), the workpiece can be easily adhered from Agent layer peeled. On the other hand, the lower limit of the adhesive force is not particularly limited, but is preferably 0.01 N / 25 mm or more, more preferably 0.05 N / 25 mm or more, and even more preferably 0.1 N / 25 mm or more.

From the viewpoint of the above-mentioned operability, especially the ease of peeling of the workpiece, the storage modulus of the adhesive layer of the temperature-sensitive adhesive sheet of this embodiment at -20 ° C is 1 MPa or more, preferably 5 MPa or more, and 10 MPa or more. Especially good. The storage modulus is 500 MPa or less, preferably 300 MPa or less, and particularly preferably 100 MPa or less. When the upper limit of the storage modulus is as described above, when the workpiece is cooled to a low temperature and the workpiece is peeled off, it is possible to prevent floating and peeling at the interface between the substrate and the adhesive layer.

The storage modulus of the temperature-sensitive adhesive sheet of the present embodiment at 80 ° C. is preferably 0.01 MPa or more, particularly preferably 0.02 MPa or more, and more preferably 0.03 MPa or more. The storage modulus is preferably 1 MPa or less, particularly preferably 0.6 MPa or less, and further preferably 0.2 MPa or less. With the storage modulus in the above range, the adhesion to glass at 80 ° C (and the adhesion to glass at 23 ° C) easily meets the aforementioned values.

Moreover, the storage modulus of the adhesive layer of the temperature-sensitive adhesive sheet of this embodiment at 23 ° C is preferably 0.05 MPa or more, particularly preferably 0.08 MPa or more, and further preferably 0.1 MPa or more. The storage modulus is preferably 3 MPa or less, particularly preferably 1 MPa or less, and further preferably 0.3 MPa or less. With the storage modulus in the above range, the adhesion to glass at 23 ° C (and the adhesion to glass at 80 ° C) easily meets the aforementioned values.

In the adhesive layer of the temperature-sensitive adhesive sheet of this embodiment, the ratio of the storage modulus at -20 ° C to the storage modulus at 23 ° C is preferably 500% or more, and particularly preferably 1,000% or more. Above 5,000% is preferred. In this way, as the storage modulus increases with cooling from 23 ° C to -20 ° C, the peelability of the work is more excellent. The ratio of the storage modulus is preferably 100,000% or less, particularly preferably 50,000% or less, and further preferably 30,000% or less. When the upper limit value of the storage modulus ratio is as described above, it is possible to prevent the workpiece from being accidentally peeled off from the adhesive layer when the storage modulus is excessively increased with cooling from 23 ° C to -20 ° C. Therefore, when the ratio of the storage modulus is within the above-mentioned range, the coexistence of the adhesiveness at the time of fixing the workpiece and the peelability of the workpiece becomes more excellent.

In addition, the ratio of the storage modulus of the temperature-sensitive adhesive sheet of this embodiment to a storage modulus at 80 ° C to a storage modulus of 23 ° C is preferably 15% or more, and more preferably 20% or more. More than 25% is preferred. Since the lower limit value of the ratio of the storage modulus is as described above, in particular, even if the step includes a heating step, an excessive decrease in adhesion force can be suppressed, a position shift of the workpiece in the step can be prevented, and the workpiece can be more fully fixed. . The upper limit of the ratio of the storage modulus is not particularly limited, but is preferably 300% or less, particularly preferably 150% or less, and even more preferably 80% or less. When the ratio of the storage modulus is within the above-mentioned range, it is possible to perform both work fixing at normal temperature and work fixing at high temperature.

The specific structure of an example of the temperature-sensitive adhesive sheet of this embodiment is shown in FIG.
As shown in FIG. 1, the temperature-sensitive adhesive sheet 1 according to an embodiment includes two release sheets 12 a and 12 b and an adhesive layer 11, and the adhesive layer 11 is used to peel off the two release sheets 12 a and 12 b. It is held by the two release sheets 12a and 12b in a surface contact manner. The release surface of the release sheet in this specification refers to any one of the surface having release properties on the release sheet, and includes a surface subjected to a release treatment and a surface that exhibits release properties even if no release treatment is performed.

Each component
1-1. Adhesive layer The adhesive constituting the adhesive layer 11 of the temperature-sensitive adhesive sheet 1 of this embodiment is not particularly limited as long as the physical properties described above are satisfied, and an adhesive containing a polyrotaxane compound is preferred. The polyrotaxane compound has a mechanical bond between a cyclic molecule and a linear molecule penetrating the cyclic molecule, and the cyclic molecule can move freely on the linear molecule. With the sliding effect based on such a structure, the obtained adhesive exhibits high stress relaxation and plasticity effects, and while maintaining high adhesion, it can mix a large amount of the crosslinking agent described later to improve cohesion. On the other hand, it is easy to introduce a side chain crystallized at a low temperature into a cyclic molecule of a polyrotaxane compound. The polyrotaxane compound having a side chain crystallized at a low temperature in this way becomes a non-adhesive component at a low temperature. In addition, polyrotaxane compounds are incompatible at low temperatures and tend to cause segregation on the surface of the adhesive layer. Therefore, when the adhesive layer 11 is cooled to a low temperature, the polyrotaxane compound of a non-adhesive component segregates on the surface of the adhesive layer 11, and thereby the adhesive force of the adhesive layer 11 is significantly reduced. In this way, the adhesive containing the polyrotaxane compound can exhibit a high adhesive force at room temperature and high temperature, and its adhesive force is significantly reduced when cooled to a low temperature. Therefore, the adhesive layer 11 made of an adhesive containing a polyrotaxane compound easily meets the aforementioned physical properties.

The type of the adhesive constituting the adhesive layer 11 may be, for example, any of an acrylic adhesive, a polyester adhesive, a urethane adhesive, a rubber adhesive, and a silicone adhesive. The adhesive may be any of an emulsion type, a solvent type, and a solventless type, and may be either a crosslinked type or a non-crosslinked type. Among these, an acrylic adhesive which easily satisfies the aforementioned physical properties and is also excellent in adhesive properties is preferred.

In addition, the acrylic adhesive may be an active energy ray-hardenable substance or an active energy ray non-hardenable substance. In order to exert the effect of the polyrotaxane compound, an active energy ray non-hardenable substance is used. Better. As an active energy ray non-hardening acrylic adhesive, a crosslinked type is particularly preferred, and a thermally crosslinked type is also preferred.

The adhesive of this embodiment is an adhesive composition containing a (meth) acrylate polymer (A), a crosslinking agent (B), and a polyrotaxane compound (C) (hereinafter referred to as "adhesiveness" In the case of "composition P"), an adhesive (adhesive obtained by crosslinking the adhesive composition P) is particularly preferred. If it is such an adhesive, it is easy to satisfy the above-mentioned physical properties, and because it exhibits good adhesive force and predetermined cohesive force, it also has excellent durability. In this specification, (meth) acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms. In addition, "polymer" is set as the concept which also includes "copolymer".

(1) Ingredients of the adhesive composition P
(1-1) (meth) acrylate polymer (A)
The glass transition temperature (Tg) of the (meth) acrylate polymer (A) is preferably 0 ° C or lower, particularly preferably -20 ° C or lower, and further preferably -40 ° C or lower. The glass transition temperature (Tg) is preferably -80 ° C or more, and particularly preferably -70 ° C or more. The temperature is preferably -60 ° C or higher. When the glass transition temperature (Tg) of the (meth) acrylate polymer (A) is -20 ° C or lower, the obtained adhesive easily exhibits appropriate viscoelasticity, and furthermore, the adhesive force at normal temperature and high temperature can be improved. Easily peelable at low temperatures. The method for measuring the glass transition temperature (Tg) is shown in the test example described later.

The (meth) acrylate polymer (A) includes a monomer (reactive functional group-containing monomer) containing an alkyl (meth) acrylate and a reactive functional group in the molecule as a constituent of the polymer. Monomer units are preferred.

The (meth) acrylate polymer (A) can exhibit good adhesion by containing an alkyl (meth) acrylate as a monomer constituting the polymer. The alkyl (meth) acrylate is preferably an alkyl (meth) acrylate having 1 to 20 carbon atoms in the alkyl group. The alkyl group may be linear or branched, or may have a cyclic structure.

Alkyl (meth) acrylates having 1 to 20 carbon atoms as the alkyl group include those having a glass transition temperature (Tg) of 30 ° C or lower as homopolymers (hereinafter referred to as "low Tg alkyl acrylates" "). By containing such a low Tg alkyl acrylate as a constituent monomer unit, it is easy to set the glass transition temperature (Tg) of the (meth) acrylate polymer (A) to the aforementioned range.

Examples of the low Tg alkyl acrylate include, for example, n-butyl acrylate (Tg-55 ° C), n-octyl acrylate (Tg-65 ° C), isooctyl acrylate (Tg-58 ° C), and acrylic acid 2 -Ethylhexyl (Tg-70 ° C), isononyl acrylate (Tg-58 ° C), isodecyl acrylate (Tg-60 ° C), isodecyl methacrylate (Tg-41 ° C), methacrylic acid N-dodecyl (Tg-65 ° C), n-tridecyl acrylate (Tg-55 ° C), n-tridecyl methacrylate (-40 ° C) and the like. Among them, from the viewpoint of making the adhesive strength at room temperature and high temperature and the easy peelability at low temperature more excellent, as the low-Tg alkyl acrylate, a homopolymer having a Tg of -45 ° C or lower is preferred, It is especially preferable to be below -50 ° C. Specifically, n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferred. These may be used alone or in combination of two or more.

The (meth) acrylate polymer (A) preferably contains a low Tg alkyl acrylate having a lower limit value of 50% by mass or more as a monomer unit constituting the polymer, and particularly preferably contains 60% by mass or more. The content is more preferably 70% by mass or more. When the lower limit of the content is as described above, it is easier to set the glass transition temperature (Tg) of the (meth) acrylate polymer (A) to the aforementioned range.

On the other hand, the (meth) acrylate polymer (A) preferably contains the aforementioned low Tg alkyl acrylate having an upper limit value of 99% by mass or less as a monomer unit constituting the polymer, and contains 97% by mass. The following is particularly preferred, and the content is more preferably 95% by mass or less. With the above-mentioned upper limit of the content, a suitable amount of other monomer components (particularly, a reactive functional group-containing monomer) can be introduced into the (meth) acrylate polymer (A).

The (meth) acrylate polymer (A) may contain a monomer having a glass transition temperature (Tg) of greater than 0 ° C. of the homopolymer (hereinafter referred to as “high Tg alkyl acrylate”) as the above. Alkyl (meth) acrylates having 1 to 20 carbon atoms in the alkyl group. By containing such a high Tg alkyl acrylate as a constituent monomer unit, the cohesive force of the obtained adhesive can be improved, and the adhesive force at high temperature can be improved.

Examples of the high Tg alkyl acrylate include, for example, methyl acrylate (Tg 10 ° C), methyl methacrylate (Tg 105 ° C), ethyl methacrylate (Tg 65 ° C), and n-butyl methacrylate (Tg20 ℃), isobutyl methacrylate (Tg48 ℃), tertiary butyl methacrylate (Tg107 ℃), n-octadecyl acrylate (Tg30 ℃), n-octadecyl methacrylate (Tg38 ℃), acrylic ring Hexyl ester (Tg15 ° C), cyclohexyl methacrylate (Tg66 ° C), benzyl methacrylate (Tg54 ° C), isoamyl acrylate (Tg94 ° C), isoamyl methacrylate (Tg180 ° C), adamantine Alkyl ester (Tg115 ° C), Adamantane methacrylate (Tg141 ° C), Morpholine acrylate (Tg145 ° C), and the like. Among the above, from the viewpoint of the cohesive force and glass transition temperature of the obtained adhesive, methyl acrylate is preferred. These may be used alone or in combination of two or more.

When the (meth) acrylate polymer (A) contains a high Tg alkyl acrylate as a monomer unit constituting the polymer, its content is preferably 5% by mass or more, particularly preferably 10% by mass or more, and more preferably 15% by mass. A mass% or more is preferred. The content is preferably 30% by mass or less, particularly preferably 25% by mass or less, and further preferably 20% by mass or less.

The (meth) acrylate polymer (A) contains a high Tg alkyl acrylate as a monomer unit constituting the polymer, and passes through a reactive functional group derived from the reactive functional group-containing monomer to be described later. The cross-linking agent (B) reacts to form a cross-linked structure (three-dimensional network structure), and an adhesive having a desired cohesive force can be obtained.

The (meth) acrylate polymer (A) contains a reactive functional group-containing monomer as a monomer unit constituting the polymer. Examples of the reactive functional group-containing monomer include: A hydroxyl-containing monomer (hydroxyl-containing monomer), a monomer having a carboxyl group in the molecule (carboxyl-containing monomer), and a monomer having an amine group (amine-containing monomer) in the molecule. These reactive functional group-containing monomers may be used alone or in combination of two or more.

Here, most of the cyclic molecules of the polyrotaxane compound (C) have a reactive hydroxyl group, as described above, in order to cause the polyrotaxane compound (C) to segregate on the surface of the adhesive layer 11 at a low temperature so as not to make the polyrotaxane The compound (C) is preferably reacted with the crosslinking agent (B). Therefore, as the cross-linking agent (B), it is preferable to select a material having a low reactivity with a hydroxyl group, and specifically, it is preferable to select a material having a high reactivity with a carboxyl group. Therefore, among the reactive functional group-containing monomers, a carboxyl group-containing monomer is particularly preferred. Moreover, a carboxyl group-containing monomer can also improve the adhesive force of the obtained adhesive.

Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. Among them, acrylic acid is preferred from the viewpoint of the adhesive force of the obtained adhesive. These may be used alone or in combination of two or more.

The (meth) acrylate polymer (A) preferably has a reactive functional group-containing monomer containing 1% by mass or more as a monomer unit constituting the polymer, and particularly preferably contains 2% by mass or more. Furthermore, it is more preferable to contain 3 mass% or more. Moreover, it is preferable that it contains 30 mass% or less of a reactive functional group containing monomer, it is more preferable that it contains 21 mass% or less, and it is more preferable that it contains 12 mass% or less. When the content of the reactive functional group-containing monomer is in the above range, the cohesive force of the obtained adhesive is high, and the adhesive force, particularly, the adhesive force at high temperature is high.

The (meth) acrylate polymer (A) may contain other monomers as a monomer unit constituting the polymer as necessary. As the other monomer, in order not to hinder the aforementioned action of the reactive functional group-containing monomer, it is preferred that the reactive functional group-free monomer is not used.

The (meth) acrylate polymer (A) is preferably a solution polymer obtained by using a solution polymerization method. By being a solution polymer, a polymer having a high molecular weight can be easily obtained, and an adhesive having better adhesion at high temperatures can be obtained.

The polymerization state of the (meth) acrylate polymer (A) may be a random copolymer or a block copolymer.

From the viewpoint of easy peelability at low temperature, the weight average molecular weight of the (meth) acrylate polymer (A) is preferably 200,000 or more, particularly 300,000 or more, and more preferably 350,000 or more. . The weight average molecular weight is preferably 2.5 million or less, particularly preferably 2 million or less, and even more preferably 1.6 million or less. When the upper limit value of the weight average molecular weight is as described above, the adhesive force of the obtained adhesive at normal temperature and high temperature is high. Therefore, when the weight average molecular weight of the (meth) acrylate polymer (A) is in the above range, the obtained adhesive can coexist more effectively with adhesion at room temperature and high temperature and easy peelability at low temperature. Thing. The weight average molecular weight in this specification is a value converted into a standard polystyrene measured by a gel permeation chromatography (GPC) method.

In the adhesive composition P, a (meth) acrylate polymer (A) may be used individually by 1 type, and may be used in combination of 2 or more type.

(1-2) Crosslinking agent (B)
The cross-linking agent (B) is triggered by heating of the adhesive composition P containing the cross-linking agent (B), and the (meth) acrylate polymer (A) is cross-linked to form a three-dimensional network. structure. Thereby, the cohesive force of the obtained adhesive is improved, and the adhesive force, in particular, the adhesive force at high temperature is higher.

As the cross-linking agent (B), as described above, in order to cause the polyrotaxane compound (C) to segregate on the surface of the adhesive layer 11 at a low temperature, a substance that does not react with the polyrotaxane compound (C) is preferred. Since most of the cyclic molecules of the polyrotaxane compound (C) have a reactive hydroxyl group, as the cross-linking agent (B), it is preferable to select a substance having low reactivity with a hydroxyl group and high reactivity with a carboxyl group.

Examples of the cross-linking agent (B) include a metal chelate-based cross-linking agent, an epoxy-based cross-linking agent, and an aziridine-based cross-linking agent. Particularly, the metal chelate-based cross-linking agent is used. Crosslinking agents are preferred. Moreover, a crosslinking agent (B) can be used individually by 1 type or in combination of 2 or more types.

The metal chelate-based crosslinking agent may be a chelate compound having a metal atom of aluminum, zirconium, titanium, zinc, iron, tin, or the like, and from the viewpoint of reactivity with the (meth) acrylate polymer (A) In particular, an aluminum chelate compound is preferred.

Examples of the aluminum chelate compound include, for example, aluminum diisopropoxide monooleylacetate acetate, aluminum monoisopropoxide dioleylacetate acetate, and aluminum monoisopropoxide Monooleate monoethylacetate acetate, aluminum diisopropoxide monolaurylacetate acetate, aluminum diisopropoxide monostearylacetate acetate, diisopropoxy Aluminum-isostearyl acetoacetate, aluminum monoisopropoxide-N-lauryl acetoyl-β-aluminum hydride monolauryl acetoacetate, aluminum triacetylate acetone, and ethyl acetate Aluminum acetone bis (isobutylacetamidate acetate) chelate, aluminum acetone aluminum acetoacetate bis (2-ethylhexylacetamidate acetate) chelate, aluminum acetone aluminum acetoacetate bis (dodecylethyl) Acetoacetate) chelate, aluminum acetoacetone aluminum bis (oleyl acetoacetate) chelate, and the like. Among the above, from the viewpoints of reactivity, the obtained adhesive is likely to have a required adhesive force, etc., triacetam aluminum acetone is particularly preferred.

With respect to 100 parts by mass of the (meth) acrylate polymer (A), the content of the crosslinking agent (B) in the adhesive composition P is preferably at least 0.1 parts by mass, and particularly preferably at least 0.5 parts by mass. It is more preferably 0.8 parts by mass or more. The content is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and further preferably 3 parts by mass or less. When the content of the cross-linking agent (B) is in the above-mentioned range, the cohesive force of the obtained adhesive is appropriately high, and the adhesive force, particularly, the adhesive force at high temperature is high.

(1-3) Polyrotaxane compound (C)
The polyrotaxane compound (C) is a compound in which a linear molecule penetrates the openings of at least two cyclic molecules and has end groups at both ends of the linear molecule. In this polyrotaxane compound (C), a cyclic molecule can move freely on a linear molecule, and a structure in which the cyclic molecule does not detach from the linear molecule by a capping group. That is, linear molecules and cyclic molecules do not have a chemical bond such as a covalent bond, but a substance that exerts a sliding effect by a so-called mechanical bond while maintaining its form. The adhesive (adhesive composition P) of this embodiment contains a polyrotaxane compound (C) having such a mechanical bond, and the obtained adhesive exhibits high stress relaxation and plasticity effects. While maintaining high adhesion, a large amount of cross-linking agent (B) can be blended to improve cohesion.

In the polyrotaxane compound (C) according to this embodiment, a cyclic oligosaccharide having a side chain that crystallizes at a low temperature is preferred as a cyclic molecule. The polyrotaxane compound (C) having such a cyclic oligosaccharide as a cyclic molecule becomes a non-adhesive component at a low temperature. As mentioned above, since the polyrotaxane compound (C) tends to segregate on the surface of the adhesive layer 11 at a low temperature, when the adhesive layer 11 is cooled to a low temperature, a polyrotaxane compound that becomes a non-adhesive component is in the adhesive layer 11 Segregation occurs on the surface, and the adhesive force of the adhesive layer 11 is significantly reduced. In addition, in this specification, "cyclic" of a "cyclic molecule" or "cyclic oligosaccharide" means substantially "cyclic." That is, as long as it can move on a linear molecule, the cyclic molecule may be incompletely closed, and for example, it may have a helical structure.

Examples of the side chain (low-temperature crystallized side chain) crystallized at the low temperature include a caprolactone chain, a polyethylene glycol chain, a polyester chain, a polyamine chain, and a polybutadiene chain.

Examples of the cyclic oligosaccharide include cyclodextrin such as α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin. These cyclodextrin have a reactive hydroxyl group, and it is easy to introduce | transduce a side chain which crystallized at low temperature through this hydroxyl group. Among these, α-cyclodextrin is particularly preferred from the viewpoint of easy peelability at low temperatures. The cyclic molecule of the polyrotaxane compound (C) may be a mixture of two or more kinds in the polyrotaxane compound (C) or the adhesive (adhesive composition P).

The linear molecule of the polyrotaxane compound (C) is enclosed by a cyclic molecule, and a molecule or substance capable of integration not by a chemical bond such as a covalent bond, but by a mechanical bond, as long as it is a straight chain There is no particular limitation on the shape. In addition, in this specification, "straight-chain" of a "straight-chain molecule" means substantially "straight-chain." That is, as long as the cyclic molecule can move on the linear molecule, the linear molecule may have a branched chain.

As the linear molecule of the polyrotaxane compound (C), for example, polyethylene glycol, polypropylene glycol, polyisoprene, polyisobutylene, polybutadiene, polytetrahydrofuran, polyacrylate, polydimethylene Siloxane, polyethylene, polypropylene and the like are preferred, and these linear molecules may be mixed in the adhesive composition P in two or more kinds.

The lower limit of the number average molecular weight of the linear molecules of the polyrotaxane compound (C) is preferably 3,000 or more, particularly preferably 10,000 or more, and more preferably 20,000 or more. When the lower limit of the number average molecular weight is the above, the amount of movement of the cyclic molecule on the linear molecule can be secured, and the stress relaxation properties of the adhesive can be sufficiently obtained. The number average molecular weight of the linear molecules of the polyrotaxane compound (C) is preferably 300,000 or less, particularly 200,000 or less, particularly preferably 100,000 or less. When the upper limit of the number average molecular weight is the above or below, the solubility of the polyrotaxane compound (C) in a solvent, the compatibility with the (meth) acrylate polymer (A), and the like are good.

The end-capping group of the polyrotaxane compound (C) is not particularly limited as long as it is a group capable of maintaining a cyclic molecule in the form of a bamboo stick string by a linear molecule. Examples of such a group include a relatively high-volume group and an ionic group.

Specifically, as the capping group of the polyrotaxane compound (C), dinitrophenyl, cyclodextrin, adamantyl, trityl, fluorescein, Pyrene, anthracene, etc., or a main chain or side chain of a polymer having a number average molecular weight of 1,000 to 1,000,000 is preferred. These end-capping groups may also be used in the polyrotaxane compound (C) or Two or more types of the adhesive composition P are mixed.

The polyrotaxane compound (C) described above can be obtained using a conventionally known method (for example, the method described in Japanese Patent Application Laid-Open No. 2005-154675).

The content of the polyrotaxane compound (C) in the adhesive composition P of this embodiment is preferably 9 parts by mass or more with respect to 100 parts by mass of the (meth) acrylate polymer (A). It is particularly preferable that it is 18 parts by mass or more, and further more preferable that it is 27 parts by mass or more. When the lower limit of the content of the polyrotaxane compound (C) is as described above, the adhesive layer 11 is more easily peelable at a low temperature. The upper limit of the content of the polyrotaxane compound (C) is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and particularly preferably 55 parts by mass or less. When the upper limit of the content of the polyrotaxane compound (C) is as described above, the adhesive force of the adhesive layer 11 at room temperature and high temperature is more excellent.

(1-4) Various additives The adhesive composition P can be added with various additives commonly used in acrylic adhesives as needed, for example, adhesion-imparting agents, antioxidants, ultraviolet absorbers, light stabilizers, softeners, fillers, etc. Agent. The polymerization solvents and diluent solvents described below are not included in the additives constituting the adhesive composition P.

(2) Production of Adhesive Composition P The adhesive composition P can be produced by (meth) acrylate polymer (A), and the obtained (meth) acrylate polymer (A) can be crosslinked. The agent (B) and the polyrotaxane compound (C) are mixed, and an additive is added as necessary to produce the agent.

The (meth) acrylate polymer (A) can be produced by polymerizing a mixture of monomers constituting the polymer using a general radical polymerization method. The polymerization of the (meth) acrylate polymer (A) is preferably performed using a polymerization initiator and a solution polymerization method as necessary. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, and methyl ethyl ketone, and two or more of them may be used in combination.

Examples of the polymerization initiator include an azo compound, an organic peroxide, and the like, and two or more of them may be used in combination. Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), and 1,1'-azobis (cyclohexyl) Alkane 1-nitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile) ), Dimethyl 2,2'-azobis (2-methylpropionate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2 -Hydroxymethylpropionitrile), 2,2'azobis [2- (2-imidazolin-2-yl) propane], and the like.

Examples of the organic peroxide include benzoyl peroxide, tertiary butyl peroxybenzoate, cumene hydrogen peroxide, diisopropyl peroxydicarbonate, and di-n-peroxydicarbonate. Propyl ester, bis (2-ethoxyethyl) peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-butyl peroxytrimethylacetate, peroxy (3,5,5-tri Methylhexamidine), dipropylammonium peroxide, diethylammonium peroxide, and the like.

In the above polymerization step, the weight average molecular weight of the obtained polymer can be adjusted by blending a chain transfer agent such as 2-hydrothiothioethanol.

After the (meth) acrylate polymer (A) is obtained, the (meth) acrylate polymer is added to the (meth) acrylate polymer by adding a crosslinking agent (B), a polyrotaxane compound (C), and additives and a diluent as necessary. The solution of (A) was sufficiently mixed to obtain a solvent-diluted adhesive composition P (coating solution).

In addition, in the case where any one of the above-mentioned components is used in a solid state, or precipitation occurs when it is mixed with other components in an undiluted state, the component may be dissolved or diluted in a dilution solvent alone in advance. Only then mix with other ingredients.

Examples of the diluting solvent include aliphatic hydrocarbons such as hexane, heptane, and cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as dichloromethane and dichloroethane; methanol; Alcohols such as ethanol, propanol, butanol, 1-methoxy-2-propanol, acetone, methyl ethyl ketone, 2-pentanone, isophorone, cyclohexanone and other ketones, ethyl acetate Esters, such as esters, butyl acetate, and ethyl cyrus thurium-based solvents.

The concentration and viscosity of the coating solution prepared in this manner are not particularly limited as long as they can be applied, and can be appropriately selected according to the situation. For example, dilution is performed so that the density | concentration of the adhesive composition P may become 10-60 mass%. When a coating solution is obtained, the addition of a diluent solvent or the like is not necessary, and if the adhesive composition P has a viscosity that can be applied, the diluent solvent may not be added. At this time, the adhesive composition P is a coating solution in which a polymerization solvent of the (meth) acrylate polymer (A) is directly used as a diluent solvent.

(3) Formation of Adhesive Layer The adhesive layer 11 can be formed by crosslinking the applied adhesive composition P. The crosslinking of the adhesive composition P is preferably performed by heat treatment. The heat treatment can also be used as a drying treatment after the adhesive composition P is applied.

The heating temperature for the heat treatment is preferably 50 to 150 ° C, and particularly preferably 70 to 120 ° C. The heating time is preferably 10 seconds to 10 minutes, and particularly preferably 50 seconds to 2 minutes. After the heat treatment, it is also preferable to set a maturation period of about 1 to 2 weeks at normal temperature (for example, 23 ° C., 50% RH).

By the heat treatment (and aging) described above, the (meth) acrylate polymer (A) can be well-crosslinked through the crosslinking agent (B).

(4) The thickness of the adhesive layer is the thickness of the adhesive layer 11 (value measured in accordance with JIS K7130) of the temperature-sensitive adhesive sheet 1 of this embodiment, and the lower limit thereof is preferably 5 μm or more, and 10 μm or more It is particularly preferred, and more preferably 15 μm or more. When the lower limit of the thickness of the adhesive layer 11 is as described above, the adhesive force at room temperature and high temperature is more excellent. The upper limit of the thickness of the adhesive layer 11 is preferably 50 μm or less, particularly preferably 40 μm or less, and further preferably 30 μm or less. When the upper limit of the thickness of the adhesive layer 11 is as described above, the peelability at a low temperature is more excellent. The adhesive layer 11 may be formed as a single layer, or may be formed by laminating a plurality of layers.

1-2. Release Sheet The release sheets 12a and 12b protect the adhesive layer 11 until the temperature-sensitive adhesive sheet 1 is used, and are peeled off when the temperature-sensitive adhesive sheet 1 (adhesive layer 11) is used. In the temperature-sensitive adhesive sheet 1 of this embodiment, one or both of the release sheets 12a and 12b are not necessarily necessary.

As the release sheet 12a, 12b, for example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, or a polyethylene film can be used. Ethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionic polymer resin film, ethylene (meth) acrylic acid Copolymer film, ethylene (meth) acrylate copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc. Moreover, such a crosslinked film can also be used. Moreover, such a laminated film may be used.

It is preferable to perform a peeling process on the peeling surface (especially the surface which contacts the adhesive layer 11) of the said peeling sheet 12a, 12b. Examples of the release agent used in the peeling treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. Among the release sheets 12a and 12b, it is preferable that one of the release sheets is a heavy release-type release sheet having a large release force, and the other release sheet is a light-release type release sheet having a small release force. .

The thickness of the release sheets 12a and 12b is not particularly limited, but is usually about 20 to 150 μm.

2. Production of Temperature-Sensitive Adhesive Sheet As an example of production of the temperature-sensitive adhesive sheet 1, a case where the above-mentioned adhesive composition P is used will be described. After the coating liquid of the adhesive composition P is applied to the release surface of one of the release sheets 12a (or 12b), and the heat treatment is performed to thermally crosslink the adhesive composition P to form a coating layer, the coating is applied. The release surfaces of the other release sheet 12b (or 12a) are laminated. When the curing period is required, the curing period is left, and when the curing period is not required, the coating layer is directly made into the adhesive layer 11. Thereby, the said temperature-sensitive adhesive sheet 1 can be obtained. The heat treatment and curing conditions are as described above.

As a method for applying the coating liquid of the above-mentioned adhesive composition P, for example, a bar coating method, a blade coating method, a roll coating method, a blade coating method, a die coating method, or a gravure coating method can be used. Wait.

3. Use of Temperature-Sensitive Adhesive Sheet As described above, the temperature-sensitive adhesive sheet 1 of this embodiment can be suitably used for devices that are to be used as optical components, electronic components, etc. of a workpiece, preferably a flexible device, and particularly good. The contact surface with the adhesive layer 11 of the temperature-sensitive adhesive sheet 1 is a flexible device that is smooth and is fixed to the substrate in steps such as processing, lamination, and inspection. After the above steps are completed, the workpiece is peeled from the substrate.

FIG. 2 is a cross-sectional view showing the laminated body 4 showing the use state of the temperature-sensitive adhesive sheet 1. The laminated body 4 of this embodiment is formed by laminating a flexible device 2 as a workpiece, an adhesive layer 11 of a temperature-sensitive adhesive sheet 1, and a substrate 3 in this order. Since the laminated body 4 is a step of normal temperature and high temperature, since the flexible device 2 is firmly fixed to the substrate 3 through the adhesive layer 11, this step can be performed without any problem.

After the above steps are completed, the adhesive layer 11 (or the flexible device 2 and the substrate 3) is cooled to a low temperature. The cooling temperature is preferably -70 ° C or higher and -20 ° C or lower, particularly preferably -60 ° C or higher and -25 ° C or lower, and further preferably -50 ° C or higher and -30 ° C or lower. By cooling to the above-mentioned temperature, the adhesive force of the adhesive layer 11 is significantly reduced, whereby the flexible device 2 can be easily peeled from the substrate 3.

The embodiments described above are described for easy understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above-mentioned embodiment also includes all design changes and the purpose of an equivalent belonging to the technical scope of the present invention.

For example, one or both of the release sheets 12a and 12b of the temperature-sensitive adhesive sheet 1 may be omitted.
[Example]

Hereinafter, the present invention will be described more specifically with reference to examples and the like, but the scope of the present invention is not limited by these examples and the like.

[Example 1]
1. Preparation of (meth) acrylate polymer (A) 77 parts by mass of n-butyl acrylate, 20 parts by mass of methyl acrylate, and 3 parts by mass of acrylic acid were copolymerized using a solution polymerization method to prepare (meth) ) Acrylate polymer (A). When the molecular weight of this (meth) acrylate polymer (A) was measured using the method mentioned later, it was 800,000 weight average molecular weight (Mw).

2. Preparation of Adhesive Composition 100 parts by mass of the (meth) acrylate polymer (A) obtained in the above step 1 (solid content conversion value; the same applies hereinafter), and triethylamine as the crosslinking agent (B) 1.0 part by mass of aluminum acetone and polyrotaxane compound (C) (straight-chain molecule: polyethylene glycol, cyclic molecule: α-cyclopaste having hydroxypropyl and caprolactone chains (low-temperature crystallized side chains) Fine; end-capping group: adamantyl, weight-average molecular weight (Mw) 700,000) 20 parts by mass, mixed thoroughly, and diluted with methyl ethyl ketone to obtain a coating solution of an adhesive composition.

3. Manufacture of an adhesive sheet The coating solution of the obtained adhesive composition was apply | coated on the one side of the polyethylene terephthalate film using the blade coater using the silicone peeling agent, and the peeling process was performed. The release-treated surface of a finished heavy release type release sheet (manufactured by LINTEC, product name "SP-PET752150"). Then, the coating layer was heat-treated at 90 ° C. for 1 minute to form a coating layer.

Next, the coating layer on the obtained heavy release type release sheet and a light release type release sheet (manufactured by LINTEC Corp.) with a polyethylene terephthalate film on one side using a silicone release agent were subjected to a release treatment. , Product name "SP-PET382120"), which were laminated so that the release-treated surface of the light-peelable release sheet was in contact with the coating layer, and were produced by curing for 7 days at 23 ° C and 50% RH. An adhesive sheet having an adhesive layer having a thickness of 20 μm, that is, an adhesive sheet composed of a structure of a heavy release type release sheet / adhesive layer (thickness: 20 μm) / light release type release sheet. The thickness of the adhesive layer is a value measured in accordance with JIS K7130 using a constant pressure thickness measuring device (manufactured by Teclock Corporation, product name "PG-02").

Here, each composition (solid content conversion value) of the adhesive composition when (meth) acrylate polymer (A) is 100 mass parts (solid content conversion value) is shown in Table 1. The details of the abbreviations and the like described in Table 1 are as follows.
[(Meth) acrylate polymer (A)]
BA: n-butyl acrylate
2EHA: 2-ethylhexyl acrylate
MA: methyl acrylate
AA: Acrylic

[Examples 2 to 6, Comparative Examples 1 to 4]
The type and ratio of each monomer constituting the (meth) acrylate polymer (A), the weight average molecular weight (Mw) of the (meth) acrylate polymer (A), and the blending amount of the crosslinking agent (B) And the compounding quantity of the polyrotaxane compound (C) was changed as shown in Table 1, and it carried out similarly to Example 1, and produced the adhesive sheet.

Here, the weight average molecular weight (Mw) is a polystyrene-equivalent weight average molecular weight measured using a gel permeation chromatography (GPC) under the following conditions (GPC measurement).
＜ Measurement conditions ＞
‧GPC measuring device: manufactured by TOSOH, HLC-8020
‧GPC column (passed in the following order): made by TOSOH
TSK guard column HXL-H
TSK gel GMHXL (× 2)
TSK gel G2000HXL
‧Measurement solvent: Tetrahydrofuran‧Measurement temperature: 40 ℃

[Test Example 1] (Measurement of glass transition temperature)
The glass transition temperature (Tg) of the (meth) acrylate polymer (A) prepared in Examples and Comparative Examples was measured using a differential scanning calorimeter (manufactured by TA Instruments Japan, product name "DSC Q2000") and The temperature was increased and decreased at a rate of 20 ° C / min. The results are shown in Table 1.

[Test Example 2] (Measurement of storage modulus)
A plurality of layers of the adhesive layers of the adhesive sheets produced in the examples and comparative examples were laminated to form a laminated body having a thickness of 3 mm. From the laminated body of the obtained adhesive layer, a cylindrical body having a diameter of 8 mm (height 3 mm) was punched, and this was used as a sample.

For the above-mentioned samples, the storage modulus (MPa) was measured under the following conditions by a torsional shear method using a viscoelasticity tester (DYNAMIC ANALAYZER manufactured by REOMETRIC) in accordance with JIS K7244-6. The results are shown in Table 2.
Measurement frequency: 1Hz
Measurement temperature: -20 ℃, 23 ℃, 80 ℃

From the results obtained above, the ratio (%) of the storage modulus at -20 ° C to the storage modulus at 23 ° C and the ratio of the storage modulus at 80 ° C to the storage modulus at 23 ° C (%). The results are shown in Table 2.

[Test Example 3] (Measurement of adhesion)
The light release type release sheet was peeled from the adhesive sheet produced in the Example and the comparative example, and the exposed adhesive layer was bonded to the polyethylene terephthalate (PET) film (made by Toyobo Co., Ltd.) with an easy-adhesion layer. , Product name “PET A4300”, thickness: 100 μm), and a laminated body of a release sheet / adhesive layer / PET film was obtained. The obtained laminated body was cut into a width of 25 mm and a length of 100 mm, and this was used as a sample.

In a 23 ° C, 50% RH environment, the heavy release type peeling sheet was peeled from the sample, and the exposed adhesive layer was attached to a soda-lime glass (manufactured by Nippon Glass Glass Co., Ltd.). The kettle was pressurized at 0.5 MPa and 50 ° C for 20 minutes. Subsequently, after standing for 24 hours under the following conditions (a) to (c), the adhesive force was measured using a tensile tester (manufactured by ORIENTEC, TENSILON) at a peeling speed of 2.0 m / min and a peeling angle of 180 degrees. (Adhesion to glass; N / 25mm). Conditions other than those described here are measured in accordance with JIS Z0237: 2009. The results are shown in Table 2.
(a) -20 ℃, 50% RH
(b) 23 ℃, 50% RH
(c) 80 ° C, 50% RH

From the results obtained above, the ratio (%) of the adhesion to glass at -20 ° C to the adhesion to glass at 23 ° C and the adhesion to glass at 80 ° C to the glass at 23 ° C were calculated. Adhesion ratio (%). The results are shown in Table 2.

In a 23 ° C, 50% RH environment, the heavy-peeling release sheet was peeled from the sample, and the exposed adhesive layer was attached to a PET having a surface roughness Ra of 2.7 μm as one surface of the adherend. The above side of the film (the surface is a very smooth PET film A, thickness: 100 μm). The autoclave manufactured by Kurihara Seisakusho was pressurized at 0.5 MPa and 50 ° C for 20 minutes. Subsequently, after standing for 24 hours under the conditions of -20 ° C and 50% RH, the adhesive force was measured in the same manner as described above (the PET adhesive force A at -20 ° C; N / 25mm). The results are shown in Table 1.

Furthermore, a PET film having a surface roughness Ra of 60 μm on one side (the surface is a relatively smooth PET film B, thickness: 100 μm) was used as an adherend. The adhesion was measured in the same manner as described above (adhesion to PET at -20 ° C; N / 25mm). The results are shown in Table 2.

[Test Example 4] (Process Evaluation)
(A) When the surface of the workpiece is very smooth As a workpiece, a polyethylene terephthalate (PET) film (thickness: 100 μm) with a surface roughness Ra of 2.7 μm was prepared, and manufactured from the examples and comparative examples The light-peeling type peeling sheet is peeled off, and the exposed adhesive layer is bonded to the above-mentioned side of the workpiece to obtain a laminate of a heavy-peeling type release sheet / adhesive layer / PET film. The obtained laminated body was cut into a width of 25 mm and a length of 100 mm.

In a 23 ° C, 50% RH environment, the heavy-peeling release sheet was peeled from the laminated body, and the exposed adhesive layer was attached to a soda-lime glass (manufactured by Nippon Glass Glass Co., Ltd.), followed by an autoclave made by Kurihara Seisakusho This was pressurized at 0.5 MPa and 50 ° C for 20 minutes, and this was used as a sample. As a high-temperature process, the obtained sample was put into a high-temperature condition of 150 ° C. and 50% RH for 30 minutes. Subsequently, as a low-temperature process, a low-temperature condition of -20 ° C and 50% RH was put for 1 hour, and then the PET film was peeled from the adhesive layer.

In the above-mentioned high-temperature process, the state of the interface between the PET film and the adhesive layer and the interface between the adhesive layer and the soda-lime glass were confirmed, and the high-temperature process evaluation (A) was performed based on the following criteria. The results are shown in Table 2.
◎ ... In the high temperature step, no floating and peeling occurs at each interface, and the PET film is firmly fixed to the soda-lime glass.
○ ... At the high temperature step, floating and peeling were slightly observed at the interface.
╳ ... In the high-temperature step, floating and peeling occurred at the interface and peeling occurred.

In the low-temperature process described above, the ease of peeling and the interface state between the PET film and the adhesive layer were confirmed, and the low-temperature process evaluation (A) was performed based on the following criteria. The results are shown in Table 2.
◎ ... Peeling is easy at the interface between the adhesive layer and the PET film. After peeling, the adhesive layer also adheres to the soda-lime glass.
○ ... The peeling at the interface between the adhesive layer and the PET film is easy. After the peeling, floating at the interface between the soda lime glass and the adhesive layer was observed.
╳ ... peeling at the interface between the adhesive layer and the PET film is difficult. (The laminated body of the PET film and the adhesive layer is peeled from the soda-lime glass).

(B) When the surface of the workpiece is relatively smooth, a PET film (thickness: 100 μm) having a surface roughness Ra of 60 μm on one side is prepared as a workpiece. Using this workpiece, a process evaluation (B) for evaluating high and low temperatures was performed in the same manner as the process evaluation (A). The results are shown in Table 2.

[Table 1]

[Table 2]

It is clear from Table 2 that the temperature-sensitive adhesive sheet manufactured in the example can exhibit excellent adhesion at normal temperature and high temperature, and can securely fix the workpiece to the substrate in the step. Moreover, when using this temperature-sensitive adhesive sheet, a workpiece can be easily peeled from a board | substrate by cooling at low temperature.
[Industrial availability]

The temperature-sensitive adhesive sheet of the present invention is particularly suitable as a step adhesive sheet used in steps such as processing, lamination, and inspection of a flexible device.

1‧‧‧ temperature-sensitive adhesive sheet

11‧‧‧ Adhesive layer

12a, 12b ‧‧‧ peeling sheet

2‧‧‧Workpiece (flexible device)

3‧‧‧ substrate

4‧‧‧ laminated body

FIG. 1 is a cross-sectional view of a temperature-sensitive adhesive sheet according to an embodiment of the present invention.

Fig. 2 is a sectional view of a laminated body according to an embodiment of the present invention.

Claims (14)

A temperature-sensitive adhesive sheet is a temperature-sensitive adhesive sheet including at least an adhesive layer, which is characterized in that: Adhesion to glass at -20 ° C is less than 1.5N / 25mm, Adhesion to glass at 80 ° C is above 2.0N / 25mm, The storage modulus of the adhesive layer at -20 ° C is 1 MPa to 500 MPa. The temperature-sensitive adhesive sheet according to item 1 of the scope of patent application, wherein the ratio of the adhesion force to glass at -20 ° C to the adhesion force to glass at 23 ° C is 1% or more and 40% or less. The temperature-sensitive adhesive sheet according to item 1 of the scope of the patent application, wherein the ratio of the adhesion force to the glass at 80 ° C to the adhesion force to the glass at 23 ° C is 10% to 300%. The temperature-sensitive adhesive sheet according to item 1 of the patent application range, wherein the storage modulus of the aforementioned adhesive layer at 80 ° C. is 0.01 MPa or more and 1 MPa or less. The temperature-sensitive adhesive sheet according to item 1 of the patent application range, wherein the aforementioned adhesive layer is composed of an adhesive containing a polyrotaxane compound. The temperature-sensitive adhesive sheet according to item 5 of the scope of patent application, wherein the aforementioned adhesive is composed of a (meth) acrylate polymer (A), a crosslinking agent (B), and a polyrotaxane compound (C). Formed by an adhesive composition. The temperature-sensitive adhesive sheet according to item 6 of the patent application range, wherein the (meth) acrylate polymer (A) contains a monomer having a carboxyl group in the molecule as a monomer unit constituting the polymer. The temperature-sensitive adhesive sheet according to item 6 of the patent application range, wherein the cross-linking agent (B) is a metal chelate-based cross-linking agent. The temperature-sensitive adhesive sheet according to item 1 of the scope of patent application, which is used in the step of fixing the workpiece to the substrate through the aforementioned adhesive layer, and after the step, peeling the aforementioned workpiece from the aforementioned adhesive layer. . The temperature-sensitive adhesive sheet according to item 9 of the scope of patent application, wherein the surface roughness Ra of the surface on the adhesive layer side of the workpiece is 0.01 μm or more and 80 μm or less. The temperature-sensitive adhesive sheet according to item 9 of the scope of patent application, wherein in the foregoing step, the workpiece is heated to 40 ° C or higher and 200 ° C or lower. The temperature-sensitive adhesive sheet according to item 9 of the patent application scope, wherein the aforementioned workpiece is a flexible device. The temperature-sensitive adhesive sheet according to item 1 of the scope of the patent application, wherein the temperature-sensitive adhesive sheet includes two release sheets, and the adhesive layer is peeled off by contacting the release surface of the two release sheets. The film holds. A laminated body is formed by laminating a flexible device, the aforementioned adhesive layer of the temperature-sensitive adhesive sheet according to any one of claims 1 to 13, and a substrate in this order.