JP2019156940A - Temperature-sensitive adhesive sheet and laminate - Google Patents

Abstract

To provide a temperature-sensitive adhesive sheet having excellent handling ability even when applied to a flexible device, and a laminate prepared using the temperature-sensitive adhesive sheet.SOLUTION: A temperature-sensitive adhesive sheet 1 at least has an adhesive layer 11. The temperature-sensitive adhesive sheet has a glass adhesion force of less than 1.5 N/25 mm at -20°C and a glass adhesion force of 2.0 N/25 mm or more at 80°C. The adhesive layer 11 has a storage elastic modulus at -20°C of 1 MPa or more and 500 MPa or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a temperature-sensitive adhesive sheet suitable for fixing and peeling a workpiece and a laminate using the same.

  In devices such as optical members and electronic members as workpieces (workpieces), the device is fixed to the substrate (pedestal) via the adhesive layer of the adhesive sheet during processing, assembly (lamination), inspection, etc. To be done. Then, after the process is completed, the workpiece is peeled from the substrate.

  As the pressure-sensitive adhesive used for the pressure-sensitive adhesive sheet as described above, for example, Patent Document 1 discloses a copolymer obtained by polymerizing stearyl acrylate, methyl acrylate and acrylic acid, or behenyl acrylate, methyl acrylate and acrylic acid. A temperature-sensitive pressure-sensitive adhesive containing a side chain crystalline polymer, which is a crosslinked polymer obtained by adding a metal chelate compound to a copolymer obtained by polymerization and performing a crosslinking reaction, is disclosed.

  Patent Document 2 discloses (meth) acrylate having a linear alkyl group of 16 to 22, (meth) acrylate having an alkyl group of 1 to 6 carbon atoms, an ethylenically unsaturated monomer having a carboxyl group or a hydroxyl group. A temperature-sensitive adhesive containing a side chain crystalline polymer obtained by polymerizing a monomer and a copolymer obtained by polymerizing a reactive fluorine compound with a metal chelate compound and a tackifier is disclosed. .

  If the temperature-sensitive adhesive disclosed in Patent Document 1 is used, the adherend can be fixed by the adhesive force exerted by the adhesive in a high-temperature atmosphere, while cooling the adhesive. Decreases and the adherend can be peeled off. Moreover, if the temperature-sensitive adhesive disclosed in Patent Document 2 is used, the adherend can be fixed by the adhesive force exerted by the adhesive under the atmospheric temperature during the normal process, By cooling, the adhesive strength is reduced, and the adherend can be peeled off.

Japanese Patent No. 5600604 Japanese Patent No. 6109932

  By the way, as said device, there were many hard things conventionally, However, The flexible device has appeared in recent years. For example, recently, as an optical member, a movement to move from a rigid liquid crystal device to a flexible organic light emitting diode (OLED) device has become active. Therefore, a pressure-sensitive adhesive sheet corresponding to such a flexible device is required.

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

  This invention is made | formed in view of said actual condition, and provides a laminated body using the thermosensitive adhesive sheet which is excellent in handling property also when applied to a flexible device, and the said thermosensitive adhesive sheet. For the purpose.

  In order to achieve the above object, first, the present invention is a temperature-sensitive pressure-sensitive adhesive sheet having at least a pressure-sensitive adhesive layer, and has an adhesive strength to glass at −20 ° C. of less than 1.5 N / 25 mm, and 80 Provided is a temperature-sensitive pressure-sensitive adhesive sheet, wherein the adhesive force to glass at ℃ is 2.0 N / 25 mm or more, and the storage elastic modulus at -20 ℃ of the pressure-sensitive adhesive layer is 1 MPa or more and 500 MPa or less ( Invention 1).

  According to the said invention (invention 1), when the said temperature sensitive adhesive sheet is applied to a flexible device, it is excellent in handling property about fixation and peeling. That is, during the normal temperature and high temperature processes, the work can be firmly fixed to the substrate, and the processes can be performed without problems. Moreover, if the said adhesive layer is cooled to low temperature, the adhesive force of the said adhesive layer will fall, and it can peel a workpiece | work from a board | substrate easily by it.

  In the said invention (invention 1), it is preferable that the ratio of the adhesive force to glass at −20 ° C. to the adhesive force to glass at 23 ° C. is 1% or more and 40% or less (invention 2).

  In the said invention (invention 1 and 2), it is preferable that the ratio of the glass adhesive force in 80 degreeC with respect to the glass adhesive force in 23 degreeC is 10% or more and 300% or less (invention 3).

  In the said invention (invention 1-3), it is preferable that the storage elastic modulus in 80 degreeC of the said adhesive layer is 0.01 Mpa or more and 1 Mpa or less (invention 4).

  In the said invention (invention 1-4), it is preferable that the said adhesive layer consists of an adhesive containing a polyrotaxane compound (invention 5).

  In the said invention (invention 5), the said adhesive is formed from the adhesive composition containing a (meth) acrylic acid ester polymer (A), a crosslinking agent (B), and a polyrotaxane compound (C). (Invention 6).

  In the said invention (invention 6), it is preferable that the said (meth) acrylic acid ester polymer (A) contains the monomer which has a carboxy group in a molecule | numerator as a monomer unit which comprises the said polymer (invention 7). ).

  In the said invention (invention 6 and 7), it is preferable that the said crosslinking agent (B) is a metal chelate type crosslinking agent (invention 8).

  The temperature-sensitive adhesive sheet according to the above inventions (Inventions 1 to 8) is used for fixing a work to a substrate through the pressure-sensitive adhesive layer during the process, and peeling the work from the pressure-sensitive adhesive layer after the process is completed. It is preferably used (Invention 9).

  In the said invention (invention 9), it is preferable that surface roughness Ra of the surface at the side of the said adhesive layer in the said workpiece | work is 0.01 micrometer or more and 80 micrometers or less (invention 10).

  In the said invention (invention 9 and 10), a workpiece | work may be heated at 40 to 200 degreeC during the said process (invention 11).

  In the said invention (invention 9-11), the said workpiece | work may be a flexible device (invention 12).

  In the said invention (invention 1-12), the said thermosensitive adhesive sheet is equipped with the 2 peeling sheet, The said peeling so that the said adhesive layer may contact the peeling surface of the said 2 peeling sheet It is preferable to be sandwiched between sheets (Invention 13).

  2ndly, this invention provides the laminated body formed by laminating | stacking the flexible device, the said adhesive layer of the said thermosensitive adhesive sheet (invention 1-13), and a board | substrate in that order (invention 14).

  The thermosensitive adhesive sheet according to the present invention is excellent in handling properties for fixing and peeling even when applied to a flexible device. Moreover, the laminated body which concerns on this invention is excellent in handling property.

It is sectional drawing of the temperature sensitive adhesive sheet which concerns on one Embodiment of this invention. It is sectional drawing of the laminated body which concerns on one Embodiment of this invention.

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

  The temperature-sensitive pressure-sensitive adhesive sheet according to this embodiment is a process of processing, assembling (stacking), and inspecting devices such as optical members and electronic members as workpieces (workpieces). It is preferably used for fixing to a substrate via an adhesive layer. After completion of the above process, the work is peeled from the substrate. In addition, said board | substrate is for supporting and fixing a workpiece | work in a process, and also contains concepts, such as a base.

  Although it does not specifically limit as a workpiece | work, Flexible devices, such as a flexible optical member and an electronic member, are preferable. Moreover, as a workpiece | work, the workpiece | work in which a heating process (For example, a heating process of 40 degreeC or more and 200 degrees C or less) is included in the said process is preferable. As such a heating process, for example, a metal vapor deposition process for forming a wiring of a transparent electrode, a resin curing process, and the like can be cited. From these viewpoints, as a work, 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.

  Further, the substrate is not particularly limited as long as the workpiece can be fixed via the pressure-sensitive adhesive layer of the temperature-sensitive pressure-sensitive adhesive sheet, but a heating step such as a metal vapor deposition step or a resin curing step is performed during the above steps. Even if it is contained, a material that does not deform or change its appearance is preferable. In addition, the workpiece is bonded to the substrate via the pressure-sensitive adhesive layer of the temperature-sensitive pressure-sensitive adhesive sheet, but the pressure-sensitive adhesive layer and the substrate are not sufficiently fixed in the above steps and in the step of peeling the workpiece. must not. For example, if the surface of the substrate is rough, the adhesiveness between the substrate and the pressure-sensitive adhesive layer is lowered, and there may be a problem that the pressure-sensitive adhesive layer is peeled off from the substrate during the process. Therefore, the surface of the substrate on the workpiece fixing side is preferably smooth. From these viewpoints, a glass substrate is particularly preferable as the substrate.

  The temperature-sensitive adhesive sheet according to this embodiment has a glass adhesive strength at −20 ° C. of less than 1.5 N / 25 mm, and a glass adhesive strength at 80 ° C. of 2.0 N / 25 mm or more. And the adhesive layer of the temperature-sensitive adhesive sheet which concerns on this embodiment is 1 MPa or more and 500 MPa or less in storage elastic modulus in -20 degreeC. Handling of fixing and peeling even when the temperature-sensitive adhesive sheet is applied to a flexible device because the adhesive strength to glass at −20 ° C. and 80 ° C. and the storage elastic modulus at −20 ° C. are the above values. Excellent in properties. Specifically, in the normal temperature and high temperature processes, the work can be firmly fixed to the substrate by the adhesive force of the pressure-sensitive adhesive layer in the temperature-sensitive adhesive sheet, and the process can be performed without problems. On the other hand, if the pressure-sensitive adhesive layer (or workpiece / substrate) is cooled to a low temperature (preferably cooled to around −20 ° C.), the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer is reduced, and the workpiece can be easily removed from the substrate. Can be peeled off.

  Here, the adhesive force in the present specification basically means an adhesive force measured by a 180-degree peeling method according to JIS Z0237: 2009. The measurement sample is 25 mm wide and 100 mm long. Affixed to the adherend and pressurized at 0.5 MPa, 50 ° C. for 20 minutes, left under normal pressure, desired temperature, 50% RH for 24 hours, and then peeled at a rate of 2.0 m / min. Shall be measured. In addition, “adhesive strength to glass” in the present specification refers to adhesive strength to soda lime glass. Furthermore, the measuring method of the storage elastic modulus in this specification is as showing in the test example mentioned later.

  As a workpiece to which the temperature-sensitive adhesive sheet according to the present embodiment is applied, a surface that is in contact with the pressure-sensitive adhesive layer of the temperature-sensitive adhesive sheet is preferably smooth to some extent. Specifically, the surface roughness Ra of the surface on the pressure-sensitive adhesive layer side of the workpiece is preferably 80 μm or less, particularly preferably 40 μm or less, and further preferably 10 μm or less. Thus, when the contact surface of the workpiece with the pressure-sensitive adhesive layer is smooth to some extent, the above-described adhesion at the time of fixing the workpiece is more effectively exhibited.

  The lower limit value of the surface roughness Ra of the surface on the pressure-sensitive adhesive layer side of the workpiece is not particularly limited, but is preferably 0.01 μm or more, particularly preferably 0.1 μm or more, and more preferably 1 μm or more. Preferably there is. When the lower limit value of the surface roughness Ra is the above, the above-described adhesion at the time of workpiece fixing and easy peeling at the time of workpiece peeling are more effectively exhibited. Furthermore, the surface roughness Ra of the surface on the pressure-sensitive adhesive layer side of the workpiece is preferably larger than the surface roughness Ra of the substrate. By doing in this way, a workpiece | work can be peeled in the state by which the adhesive layer was firmly fixed to the board | substrate side at the time of workpiece | work peeling.

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

  From the viewpoint of the above handling properties, in particular, easy peelability of the workpiece, the temperature-sensitive adhesive sheet according to this embodiment preferably has an adhesive force to glass at −20 ° C. of 1.3 N / 25 mm or less, particularly 1 It is preferable that it is 0.0 N / 25 mm or less. The lower limit of the adhesive strength to glass at −20 ° C. is preferably 0.01 N / 25 mm or more, particularly 0.1 N, from the viewpoint of peeling the workpiece while the pressure-sensitive adhesive layer is firmly fixed to the substrate side. / 25 mm or more is preferable.

  From the viewpoint of the above handling properties, particularly the work fixing during the process, the temperature-sensitive adhesive sheet according to this embodiment has an adhesive strength to glass at 80 ° C. of 2.0 N / 25 mm or more, and 2.2 N / 25 mm or more. It is preferable that it is 2.8N / 25mm or more especially. If the lower limit of the adhesion to glass at 80 ° C. is the above, even if a heating process is included in the process, the occurrence of misalignment or peeling of the work in the process is suppressed, and the work is sufficiently Can be fixed. On the other hand, the upper limit value of the adhesive force 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. preferable.

  In addition, from the viewpoint of handling characteristics, particularly work fixing during the process, the temperature-sensitive adhesive sheet according to the present embodiment preferably has an adhesive strength to glass at 23 ° C. of 2.0 N / 25 mm or more, in particular. It is preferably 2.8 N / 25 mm or more, and more preferably 3.4 N / 25 mm or more. On the other hand, the upper limit of the adhesive strength to glass at 23 ° C. is preferably 30 N / 25 mm or less, particularly preferably 15 N / 25 mm or less, and more preferably 10 N / 25 mm or less from the viewpoint of reworkability. Is preferred.

  In the temperature-sensitive adhesive sheet according to this embodiment, the ratio of glass adhesive strength at −20 ° C. to glass adhesive strength at 23 ° C. is preferably 1% or more, particularly 5% or more. Is preferable, and more preferably 10% or more. When the lower limit value of the adhesive force ratio is as described above, it is possible to prevent the occurrence of floating / peeling at the interface between the substrate and the adhesive layer when the workpiece is peeled off after cooling to a low temperature. The ratio of the adhesive strength is preferably 40% or less, particularly preferably 35% or less, and further preferably 30% or less. When the upper limit value of the ratio of the adhesive strength is as described above, the adhesive strength is sufficiently lowered when cooled to a low temperature, and the workpiece peelability is further improved. Therefore, when the ratio of the adhesive strength is within the above range, both the adhesion at the time of fixing the workpiece and the easy peelability of the workpiece are more excellent.

  Moreover, in the temperature-sensitive adhesive sheet according to the present embodiment, the ratio of glass adhesive strength at 80 ° C. to glass adhesive strength at 23 ° C. is preferably 10% or more, particularly 30% or more. It is preferable that it is 50% or more. If the lower limit value of the adhesive force ratio is the above, even if a heating step is included in the process, the adhesive force does not decrease too much, preventing the occurrence of workpiece displacement and peeling during the process. Thus, the work can be more sufficiently fixed. The upper limit value of the ratio of the adhesive strength is not particularly limited, but is preferably 300% or less, particularly preferably 200% or less, and more preferably 100% or less. Therefore, when the ratio of the adhesive strength is within the above range, both the work fixing at normal temperature and the work fixing at high temperature can be performed more favorably.

  The adhesive force with respect to a polyethylene terephthalate (PET) film having a surface roughness Ra of 2.7 μm (surface is very smooth) at −20 ° C. of the temperature-sensitive adhesive sheet according to this embodiment is 1.2 N / 25 mm or less. In particular, it is preferably 1.0 N / 25 mm or less, and more preferably 0.8 N / 25 mm or less. As a result, when the surface state of the workpiece is equivalent to that of the PET film, when the pressure-sensitive adhesive layer (or workpiece / substrate) is cooled to a low temperature (preferably cooled to around −20 ° C.), the workpiece is removed from the pressure-sensitive adhesive layer. Can be peeled off more easily. On the other hand, the lower limit value of the adhesive strength 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. It is preferable.

  Moreover, the adhesive force with respect to PET film whose surface roughness Ra is 60 micrometers (surface is comparatively smooth) in -20 degreeC of the thermosensitive adhesive sheet which concerns on this embodiment is 1.0 N / 25mm or less. In particular, it is preferably 0.8 N / 25 mm or less, more preferably 0.6 N / 25 mm or less. As a result, when the surface state of the workpiece is equivalent to that of the PET film, when the pressure-sensitive adhesive layer (or workpiece / substrate) is cooled to a low temperature (preferably cooled to around −20 ° C.), the workpiece is removed from the pressure-sensitive adhesive layer. Can be easily peeled off. On the other hand, the lower limit value of the adhesive strength 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. It is preferable.

  From the viewpoint of the above handling properties, in particular, easy peelability of the workpiece, the storage elastic modulus at −20 ° C. of the pressure-sensitive adhesive layer of the temperature-sensitive adhesive sheet according to this embodiment is 1 MPa or more, and 5 MPa or more. It is particularly preferable that the pressure is 10 MPa or more. The storage elastic modulus is 500 MPa or less, preferably 300 MPa or less, particularly preferably 100 MPa or less. When the upper limit value of the storage elastic modulus is as described above, it is possible to prevent the occurrence of floating / peeling at the interface between the substrate and the pressure-sensitive adhesive layer when the workpiece is peeled after being cooled to a low temperature.

  The pressure-sensitive adhesive layer of the temperature-sensitive pressure-sensitive adhesive sheet according to this embodiment preferably has a storage elastic modulus at 80 ° C. of 0.01 MPa or more, particularly preferably 0.02 MPa or more, and more preferably It is preferable that it is 03 MPa or more. The storage elastic modulus is preferably 1 MPa or less, particularly preferably 0.6 MPa or less, and further preferably 0.2 MPa or less. When the storage elastic modulus is within the above range, the adhesion to glass at 80 ° C. (and the adhesion to glass at 23 ° C.) can easily satisfy the above-described value.

  Furthermore, the pressure-sensitive adhesive layer of the temperature-sensitive pressure-sensitive adhesive sheet according to this embodiment preferably has a storage elastic modulus at 23 ° C. of 0.05 MPa or more, particularly preferably 0.08 MPa or more, and more preferably 0. It is preferably 1 MPa or more. The storage elastic modulus is preferably 3 MPa or less, particularly preferably 1 MPa or less, and further preferably 0.3 MPa or less. When the storage elastic modulus is within the above range, the adhesion to glass at 23 ° C. (and the adhesion to glass at 80 ° C.) can easily satisfy the above-described value.

  In the pressure-sensitive adhesive layer of the temperature-sensitive adhesive sheet according to this embodiment, the ratio of the storage elastic modulus at −20 ° C. to the storage elastic modulus at 23 ° C. is preferably 500% or more, particularly 1,000% or more. It is preferable that it is 5,000% or more. As described above, the storage elastic modulus increases with cooling from 23 ° C. to −20 ° C., so that the workpiece peelability is further improved. The ratio of the storage elastic modulus is preferably 100,000% or less, particularly preferably 50,000% or less, and more preferably 30,000% or less. When the upper limit value of the storage elastic modulus ratio is as described above, the storage elastic modulus increases excessively with cooling from 23 ° C. to −20 ° C., and the work is inadvertently peeled off from the adhesive layer. This can be prevented. Therefore, when the ratio of the storage elastic modulus is within the above range, the coexistence between the adhesiveness at the time of fixing the workpiece and the peelability of the workpiece becomes more excellent.

  Further, in the pressure-sensitive adhesive layer of the temperature-sensitive pressure-sensitive adhesive sheet according to the present embodiment, the ratio of the storage elastic modulus at 80 ° C. to the storage elastic modulus at 23 ° C. is preferably 15% or more, particularly 20% or more. It is preferable that it is 25% or more. The lower limit value of the ratio of the storage elastic modulus is as described above. In particular, even if a heating step is included in the process, it is suppressed that the adhesive force is excessively reduced, and the occurrence of positional deviation or peeling of the workpiece occurs during the process. Can be prevented and the work can be more sufficiently fixed. The upper limit of the ratio of the storage elastic modulus is not particularly limited, but is preferably 300% or less, particularly preferably 150% or less, and more preferably 80% or less. When the ratio of the storage elastic modulus is within the above range, both work fixing at normal temperature and work fixing at high temperature can be performed more satisfactorily.

A specific configuration as an example of the temperature-sensitive adhesive sheet according to the present embodiment is shown in FIG.
As shown in FIG. 1, the temperature-sensitive adhesive sheet 1 according to an embodiment includes two release sheets 12a and 12b and the two release sheets 12a and 12b so as to be in contact with the release surfaces of the two release sheets 12a and 12b. It is comprised from the adhesive layer 11 pinched | interposed into peeling sheet 12a, 12b. In addition, the release surface of the release sheet in this specification refers to a surface having peelability in the release sheet, and includes both a surface that has been subjected to a release treatment and a surface that exhibits peelability without being subjected to a release treatment. .

1. Each member 1-1. Adhesive layer Although the adhesive which comprises the adhesive layer 11 of the thermosensitive adhesive sheet 1 which concerns on this embodiment will not be specifically limited if said physical property is satisfy | filled, It is preferable that it is an adhesive containing a polyrotaxane compound. . The polyrotaxane compound has a mechanical bond between a cyclic molecule and a linear molecule penetrating the cyclic molecule, and the cyclic molecule can freely move on the linear molecule. Due to the sliding effect based on such a structure, the resulting pressure-sensitive adhesive exhibits high stress relaxation properties and a plastic effect, and can improve cohesion by blending many cross-linking agents described later while maintaining high adhesive strength. It becomes possible. On the other hand, it is easy to introduce a side chain that crystallizes at a low temperature into the cyclic molecule of the polyrotaxane compound. Thus, the polyrotaxane compound into which the side chain that crystallizes at a low temperature is introduced becomes a non-adhesive component at a low temperature. Further, the polyrotaxane compound tends to become incompatible at a low temperature and segregate on the surface of the pressure-sensitive adhesive layer. Therefore, when the pressure-sensitive adhesive layer 11 is cooled to a low temperature, the polyrotaxane compound that has become a non-sticky component is segregated on the surface of the pressure-sensitive adhesive layer 11, thereby significantly reducing the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer 11. As described above, the pressure-sensitive adhesive containing the polyrotaxane compound can exhibit high pressure-sensitive adhesive strength at room temperature and high temperature, and when cooled to low temperature, the pressure-sensitive adhesive strength is remarkably reduced. Therefore, the pressure-sensitive adhesive layer 11 made of a pressure-sensitive adhesive containing a polyrotaxane compound easily satisfies the physical properties described above.

  As a kind of adhesive which comprises the adhesive layer 11, any of an acrylic adhesive, a polyester adhesive, a polyurethane adhesive, a rubber adhesive, a silicone adhesive, etc. may be sufficient, for example. The pressure-sensitive adhesive may be any of an emulsion type, a solvent type, or a solventless type, and may be either a crosslinked type or a non-crosslinked type. Among them, an acrylic pressure-sensitive adhesive that easily satisfies the above-described physical properties and is excellent in adhesive physical properties is preferable.

  In addition, the acrylic pressure-sensitive adhesive may be active energy ray-curable or non-active energy ray-curable, but in order to effectively exhibit the action of the polyrotaxane compound, It is preferable that the active energy ray is non-curable. As the active energy ray non-curable acrylic pressure-sensitive adhesive, a cross-linking type is particularly preferable, and a thermal cross-linking type is more preferable.

  In particular, the pressure-sensitive adhesive according to this embodiment is a pressure-sensitive adhesive composition (hereinafter referred to as “pressure-sensitive adhesive composition”) containing a (meth) acrylic acid ester polymer (A), a crosslinking agent (B), and a polyrotaxane compound (C). It is preferable that it is an adhesive (adhesive formed by crosslinking the adhesive composition P). With such an adhesive, the above-described physical properties are easily satisfied, and since excellent adhesive force and predetermined cohesive force are exhibited, the durability is also excellent. In the present specification, (meth) acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms. Further, the “polymer” includes the concept of “copolymer”.

(1) Component (1-1) (meth) acrylic acid ester polymer (A) of adhesive composition P
The (meth) acrylic acid ester polymer (A) has a glass transition temperature (Tg) of preferably 0 ° C. or lower, particularly preferably −20 ° C. or lower, and more preferably −40 ° C. or lower. It is preferable. The glass transition temperature (Tg) is preferably −80 ° C. or higher, particularly preferably −70 ° C. or higher, and more preferably −60 ° C. or higher. When the glass transition temperature (Tg) of the (meth) acrylic acid ester polymer (A) is −20 ° C. or lower, the resulting pressure-sensitive adhesive is likely to exhibit suitable viscoelasticity, and is adhesive at room temperature and high temperature. The force and the easy peelability at low temperature can be further improved. In addition, the measuring method of glass transition temperature (Tg) is as showing in the below-mentioned test example.

  The (meth) acrylic acid ester polymer (A) has (meth) acrylic acid alkyl ester as a monomer unit constituting the polymer and a monomer having a reactive functional group in the molecule (reactive functional group-containing monomer). It is preferable to contain.

  (Meth) acrylic acid ester polymer (A) can express preferable adhesiveness by containing (meth) acrylic acid alkylester as a monomer unit which comprises the polymer concerned. The (meth) acrylic acid alkyl ester is preferably a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group. The alkyl group may be linear or branched, or may have a cyclic structure.

  As the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group, a glass transition temperature (Tg) as a homopolymer of −30 ° C. or less (hereinafter sometimes referred to as “low Tg alkyl acrylate”). .) Is preferably contained. By containing such a low Tg alkyl acrylate as a constituent monomer unit, the glass transition temperature (Tg) of the (meth) acrylic acid ester polymer (A) can be easily set within the above-described range.

  Examples of the low Tg alkyl acrylate include n-butyl acrylate (Tg-55 ° C.), n-octyl acrylate (Tg-65 ° C.), isooctyl acrylate (Tg-58 ° C.), 2-ethylhexyl acrylate (Tg). -70 ° C), isononyl acrylate (Tg-58 ° C), isodecyl acrylate (Tg-60 ° C), isodecyl methacrylate (Tg-41 ° C), n-lauryl methacrylate (Tg-65 ° C), tridecyl acrylate (Tg-55 ° C.), tridecyl methacrylate (−40 ° C.) and the like are preferable. Among them, from the viewpoint of improving the adhesive strength at normal temperature and high temperature and easy peelability at low temperature, the Tg of the homopolymer as the low Tg alkyl acrylate is −45 ° C. or lower. More preferably, it is particularly preferably -50 ° C or lower. Specifically, n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferable. These may be used alone or in combination of two or more.

  The (meth) acrylic acid ester polymer (A) preferably contains, as a monomer unit constituting the polymer, a low Tg alkyl acrylate in a lower limit of 50% by mass or more, particularly 60% by mass or more. It is preferable to contain 70% by mass or more. When the lower limit of the content is as described above, the glass transition temperature (Tg) of the (meth) acrylic acid ester polymer (A) can be easily set in the above-described range.

  On the other hand, the (meth) acrylic acid ester polymer (A) preferably contains 99% by mass or less of the low Tg alkyl acrylate as a monomer unit constituting the polymer, and particularly 97% by mass or less. It is preferable to contain 95 mass% or less. When the upper limit of the content is as described above, a suitable amount of other monomer components (particularly reactive functional group-containing monomers) can be introduced into the (meth) acrylic acid ester polymer (A).

  The (meth) acrylic acid ester polymer (A) is a monomer having a glass transition temperature (Tg) of more than 0 ° C. as a homopolymer as a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group. (Hereinafter sometimes referred to as “high Tg alkyl acrylate”). By containing such a high Tg alkyl acrylate as a constituent monomer unit, the cohesive force of the obtained pressure-sensitive adhesive can be improved, and the pressure-sensitive adhesive force at high temperatures can be improved.

  Examples of the high Tg alkyl acrylate include methyl acrylate (Tg 10 ° C.), methyl methacrylate (Tg 105 ° C.), ethyl methacrylate (Tg 65 ° C.), n-butyl methacrylate (Tg 20 ° C.), and isobutyl methacrylate (Tg 48 ° C.). ), T-butyl methacrylate (Tg 107 ° C.), n-stearyl acrylate (Tg 30 ° C.), n-stearyl methacrylate (Tg 38 ° C.), cyclohexyl acrylate (Tg 15 ° C.), cyclohexyl methacrylate (Tg 66 ° C.), methacrylic acid Benzyl (Tg 54 ° C.), isobornyl acrylate (Tg 94 ° C.), isobornyl methacrylate (Tg 180 ° C.), adamantyl acrylate (Tg 115 ° C.), adamantyl methacrylate (Tg 141 ° C.), morpholine acrylate (Tg 145 ° C.), etc. And the like. Among these, methyl acrylate is preferable from the viewpoint of the cohesive force of the obtained pressure-sensitive adhesive and the glass transition temperature. These may be used alone or in combination of two or more.

  When the (meth) acrylic acid ester polymer (A) contains a high Tg alkyl acrylate as a monomer unit constituting the polymer, the content is preferably 5% by mass or more, particularly 10% by mass. It is preferable that the amount is 15% or more. Further, 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) acrylic acid ester polymer (A) contains a reactive functional group-containing monomer as a monomer unit constituting the polymer, and thus via a reactive functional group derived from the reactive functional group-containing monomer. Then, it reacts with a crosslinking agent (B) described later, thereby forming a crosslinked structure (three-dimensional network structure) and obtaining a pressure-sensitive adhesive having a desired cohesive force.

  The reactive functional group-containing monomer contained in the (meth) acrylic acid ester polymer (A) as a monomer unit constituting the polymer includes a monomer having a hydroxyl group in the molecule (hydroxyl group-containing monomer) and a carboxyl group in the molecule. And a monomer having a group (carboxy group-containing monomer) and a monomer having an amino group in the molecule (amino group-containing monomer). These reactive functional group-containing monomers may be used alone or in combination of two or more.

  Here, the cyclic molecule of the polyrotaxane compound (C) often has a reactive hydroxyl group. However, as described above, the polyrotaxane compound (C) is segregated on the surface of the pressure-sensitive adhesive layer 11 at a low temperature. It is preferable not to react the compound (C) and the crosslinking agent (B). For that purpose, it is preferable to select a crosslinking agent (B) that has low reactivity with a hydroxyl group, and specifically, one that has high reactivity with a carboxy group. Therefore, among the reactive functional group-containing monomers, a carboxy group-containing monomer is particularly preferable. The carboxy group-containing monomer can also increase the adhesive strength of the resulting adhesive.

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

  The (meth) acrylic acid ester polymer (A) preferably contains 1% by mass or more, particularly preferably 2% by mass or more of the reactive functional group-containing monomer as a monomer unit constituting the polymer. Further, it is preferable to contain 3% by mass or more. Further, the reactive functional group-containing monomer is preferably contained in an amount of 30% by mass or less, particularly preferably 21% by mass or less, and more preferably 12% by mass or less. When the content of the reactive functional group-containing monomer is within the above range, the pressure-sensitive adhesive obtained has a higher cohesive force and higher adhesive strength, particularly at high temperatures.

  The (meth) acrylic acid ester polymer (A) may contain other monomers as monomer units constituting the polymer, if desired. The other monomer is preferably a monomer that does not contain a reactive functional group in order not to inhibit the above-described action of the reactive functional group-containing monomer.

  The (meth) acrylic acid ester polymer (A) is preferably a solution polymer obtained by a solution polymerization method. By being a solution polymer, a polymer having a high molecular weight can be easily obtained, and an adhesive having an excellent adhesive strength at a high temperature can be obtained.

  The polymerization mode of the (meth) acrylic acid ester polymer (A) may be a random copolymer or a block copolymer.

  The weight average molecular weight of the (meth) acrylic acid ester polymer (A) is preferably 200,000 or more, particularly preferably 300,000 or more, more preferably 350,000, from the viewpoint of easy release at low temperatures. The above is preferable. The weight average molecular weight is preferably 2.5 million or less, particularly preferably 2 million or less, and further preferably 1.6 million or less. When the upper limit value of the weight average molecular weight is as described above, the pressure-sensitive adhesive obtained has higher adhesive strength at normal temperature and high temperature. Therefore, when the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is in the above range, the resulting pressure-sensitive adhesive is more effective in tackiness at normal and high temperatures and easy peelability at low temperatures. Can be compatible. In addition, the weight average molecular weight in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

  In the adhesive composition P, the (meth) acrylic acid ester polymer (A) may be used alone or in combination of two or more.

(1-2) Crosslinking agent (B)
The cross-linking agent (B) cross-links the (meth) acrylic acid ester polymer (A) using, for example, heating of the adhesive composition P containing the cross-linking agent (B) as a trigger to form a three-dimensional network structure. . Thereby, the cohesive force of the obtained adhesive improves, and the adhesive force, especially the adhesive force at high temperature becomes higher.

  As mentioned above, the crosslinking agent (B) is preferably one that does not react with the polyrotaxane compound (C) in order to segregate the polyrotaxane compound (C) on the surface of the pressure-sensitive adhesive layer 11 at a low temperature. Since the cyclic molecule of the polyrotaxane compound (C) often has a reactive hydroxyl group, the crosslinking agent (B) should be selected to have a low reactivity with the hydroxyl group and a high reactivity with the carboxy group. Is preferred.

  Examples of the crosslinking agent (B) as described above include metal chelate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, and the like, among which metal chelate crosslinking agents are preferred. In addition, a crosslinking agent (B) can be used individually by 1 type or in combination of 2 or more types.

  As the metal chelate-based crosslinking agent, there are chelate compounds whose metal atoms are aluminum, zirconium, titanium, zinc, iron, tin, etc., but from the viewpoint of reactivity with the (meth) acrylate polymer (A), the aluminum chelate Compounds are preferred.

  Examples of the aluminum chelate compound include diisopropoxy aluminum monooleyl acetoacetate, monoisopropoxy aluminum bis oleyl acetoacetate, monoisopropoxy aluminum monooleate monoethyl acetoacetate, diisopropoxy aluminum monolauryl acetoacetate, diisopropoxy Aluminum monostearyl acetoacetate, diisopropoxy aluminum monoisostearyl acetoacetate, monoisopropoxy aluminum mono-N-lauroyl-β-alanate monolauryl acetoacetate, aluminum trisacetylacetonate, monoacetylacetonate aluminum bis (isobutylacetate Acetate) chelate, monoacetylacetonate aluminum (2-ethylhexyl acetoacetate) chelate, monoacetylacetonate aluminum bis (dodecylacetoacetate) chelate, monoacetylacetonate aluminum bis (oleyl acetoacetate) chelate, and the like. Among these, aluminum trisacetylacetonate is particularly preferable from the viewpoint that the reactivity and the obtained pressure-sensitive adhesive are likely to have a desired pressure-sensitive adhesive force.

  The content of the crosslinking agent (B) in the pressure-sensitive adhesive composition P is preferably 0.1 parts by mass or more with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (A). The amount is preferably 5 parts by mass or more, and more preferably 0.8 parts by mass or more. Further, 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 range, the cohesive strength of the obtained pressure-sensitive adhesive becomes moderately high, and the pressure-sensitive adhesive strength, particularly at high temperatures, becomes higher.

(1-3) Polyrotaxane compound (C)
The polyrotaxane compound (C) is a compound in which a linear molecule penetrates through openings of at least two cyclic molecules and has a blocking group at both ends of the linear molecule. In this polyrotaxane compound (C), the cyclic molecule can freely move on the linear molecule, but the cyclic molecule has a structure in which the cyclic molecule cannot escape from the linear molecule due to the blocking group. That is, the linear molecule and the cyclic molecule maintain their forms while exhibiting a sliding effect by a so-called mechanical bond rather than a chemical bond such as a covalent bond. When the pressure-sensitive adhesive (pressure-sensitive adhesive composition P) according to this embodiment contains the polyrotaxane compound (C) having such a mechanical bond, the pressure-sensitive adhesive obtained exhibits high stress relaxation properties and a plastic effect. While maintaining a high adhesive force, it is possible to improve the cohesive force by adding a large amount of the crosslinking agent (B).

  The polyrotaxane compound (C) in the present embodiment preferably has a cyclic oligosaccharide having a side chain that crystallizes at a low temperature 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 described above, the polyrotaxane compound (C) tends to segregate on the surface of the pressure-sensitive adhesive layer 11 at a low temperature. Therefore, when the pressure-sensitive adhesive layer 11 is cooled to a low temperature, the polyrotaxane compound that has become a non-sticky component becomes the pressure-sensitive adhesive layer 11. Segregated on the surface of the adhesive layer, the adhesive strength of the adhesive layer 11 is significantly reduced. In the present specification, “cyclic” of “cyclic molecule” or “cyclic oligosaccharide” means substantially “cyclic”. In other words, the cyclic molecule may not be completely closed as long as it can move on the linear molecule, and may have a helical structure, for example.

  Examples of the side chain that crystallizes at a low temperature (low temperature crystallization side chain) include a caprolactone chain, a polyethylene glycol chain, a polyester chain, a polyamide chain, and a polybutadiene chain.

  Preferred examples of the cyclic oligosaccharide include cyclodextrins such as α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin. These cyclodextrins have reactive hydroxyl groups, and it is easy to introduce side chains that crystallize at low temperatures via the hydroxyl groups. Among these, α-cyclodextrin is particularly preferable from the viewpoint of easy releasability at low temperatures. Two or more kinds of cyclic molecules of the polyrotaxane compound (C) may be mixed in the polyrotaxane compound (C) or in the adhesive (adhesive composition P).

  The linear molecule of the polyrotaxane compound (C) is a molecule or substance that is included in a cyclic molecule and can be integrated by a mechanical bond rather than a chemical bond such as a covalent bond. If it is, it will not be specifically limited. In the present specification, “linear” of “linear molecule” means substantially “linear”. That is, the linear molecule may have a branched chain as long as the cyclic molecule can move on the linear molecule.

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

  The number average molecular weight of the linear molecule of the polyrotaxane compound (C) is preferably 3,000 or more as a lower limit, particularly preferably 10,000 or more, and more preferably 20,000 or more. preferable. When the lower limit of the number average molecular weight is not less than the above, the amount of movement of the cyclic molecule on the linear molecule is secured, and the stress relaxation property of the pressure-sensitive adhesive is sufficiently obtained. The number average molecular weight of the linear molecule of the polyrotaxane compound (C) is preferably 300,000 or less as an upper limit, particularly preferably 200,000 or less, and more preferably 100,000 or less. It is preferable. When the upper limit of the number average molecular weight is not more than the above, the solubility of the polyrotaxane compound (C) in the solvent and the compatibility with the (meth) acrylic acid ester polymer (A) are improved.

  The blocking group of the polyrotaxane compound (C) is not particularly limited as long as the cyclic molecule is a group capable of maintaining a form in which the cyclic molecule is skewered with a linear molecule. Examples of such groups include bulky groups and ionic groups.

  Specifically, the blocking group of the polyrotaxane compound (C) may be a dinitrophenyl group, a cyclodextrin, an adamantane group, a trityl group, a fluorescein, a pyrene, an anthracene, or the like, or a number average molecular weight of 1,000. A main chain or side chain of a polymer of ˜1,000,000 is preferable, and two or more of these blocking groups may be mixed in the polyrotaxane compound (C) or the adhesive composition P.

  The polyrotaxane compound (C) described above can be obtained by a conventionally known method (for example, a method described in JP-A-2005-154675).

  The content of the polyrotaxane compound (C) in the adhesive composition P according to this embodiment is 9 parts by mass or more as a lower limit value with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (A). In particular, the amount is preferably 18 parts by mass or more, and more preferably 27 parts by mass or more. When the lower limit value of the content of the polyrotaxane compound (C) is as described above, the easy peelability at a low temperature of the pressure-sensitive adhesive layer 11 becomes more excellent. Further, the content of the polyrotaxane compound (C) is preferably 70 parts by mass or less as an upper limit, more preferably 60 parts by mass or less, and particularly preferably 55 parts by mass or less. When the upper limit value of the content of the polyrotaxane compound (C) is as described above, the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer 11 at room temperature and high temperature becomes more excellent.

(1-4) Various additives For the adhesive composition P, various additives usually used in acrylic adhesives, for example, tackifiers, antioxidants, ultraviolet absorbers, light stabilizers, if desired, Softeners, fillers and the like can be added. In addition, the below-mentioned polymerization solvent and dilution solvent shall not be contained in the additive which comprises the adhesive composition P.

(2) Manufacture of adhesive composition P The adhesive composition P manufactured the (meth) acrylic acid ester polymer (A), the obtained (meth) acrylic acid ester polymer (A), and a crosslinking agent. While mixing (B) and a polyrotaxane compound (C), it can manufacture by adding an additive if desired.

  The (meth) acrylic acid ester polymer (A) can be produced by polymerizing a mixture of monomers constituting the polymer by an ordinary radical polymerization method. The polymerization of the (meth) acrylic acid ester polymer (A) is preferably carried out by a solution polymerization method using a polymerization initiator if desired. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone, and the like. Two or more kinds may be used in combination.

  Examples of the polymerization initiator include azo compounds and organic peroxides, and two or more kinds may be used in combination. Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane 1-carbonitrile), 2 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 organic peroxides include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, and di (2-ethoxyethyl) peroxy. Examples include dicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxybivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like.

  In addition, in the said superposition | polymerization process, the weight average molecular weight of the polymer obtained can be adjusted by mix | blending chain transfer agents, such as 2-mercaptoethanol.

  Once the (meth) acrylic acid ester polymer (A) is obtained, the solution of the (meth) acrylic acid ester polymer (A) is added to the crosslinking agent (B), the polyrotaxane compound (C), and optionally additives and dilutions. The adhesive composition P (coating solution) diluted with the solvent is obtained by adding the solvent and mixing thoroughly.

  When any of the above components is used in a solid state or when precipitation occurs when mixed with other components in an undiluted state, the component is used alone as a dilution solvent. It may be dissolved or diluted and then mixed with other components.

  Examples of the dilution solvent include aliphatic hydrocarbons such as hexane, heptane, and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, methanol, ethanol, propanol, butanol, Alcohols such as 1-methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone, esters such as ethyl acetate and butyl acetate, and cellosolve solvents such as ethyl cellosolve are used.

  The concentration / viscosity of the coating solution thus prepared is not particularly limited as long as it can be coated, and can be appropriately selected depending on the situation. For example, it dilutes so that the density | concentration of the adhesive composition P may be 10-60 mass%. In addition, when obtaining a coating solution, addition of a dilution solvent etc. is not a necessary condition, and if a viscosity etc. which can be coated with the adhesive composition P are not necessary, a dilution solvent does not need to be added. In this case, the adhesive composition P becomes a coating solution using the polymerization solvent of the (meth) acrylic acid ester polymer (A) as a dilution solvent.

(3) Formation of pressure-sensitive adhesive layer The pressure-sensitive adhesive layer 11 can be formed by crosslinking the applied pressure-sensitive adhesive composition P. The crosslinking of the adhesive composition P is preferably performed by heat treatment. In addition, this heat processing can also serve as the drying process after application | coating of the adhesive composition P. FIG.

  The heating temperature of 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, particularly preferably 50 seconds to 2 minutes. It is also preferable to provide a curing period of about 1 to 2 weeks at room temperature (for example, 23 ° C., 50% RH) after the heat treatment.

  By the heat treatment (and curing), the (meth) acrylic acid ester polymer (A) is well crosslinked through the crosslinking agent (B).

(4) Thickness of pressure-sensitive adhesive layer The thickness (value measured according to JIS K7130) of the pressure-sensitive adhesive layer 11 in the temperature-sensitive pressure-sensitive adhesive sheet 1 according to this embodiment is preferably 5 μm or more as a lower limit value. In particular, the thickness is preferably 10 μm or more, and more preferably 15 μm or more. When the lower limit value of the thickness of the pressure-sensitive adhesive layer 11 is as described above, the pressure-sensitive adhesive strength at room temperature and high temperature becomes more excellent. The thickness of the pressure-sensitive adhesive layer 11 is preferably 50 μm or less as an upper limit value, particularly preferably 40 μm or less, and further preferably 30 μm or less. When the upper limit value of the thickness of the pressure-sensitive adhesive layer 11 is as described above, the easy peelability at low temperatures becomes more excellent. The pressure-sensitive 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 pressure-sensitive adhesive layer 11 until the temperature-sensitive pressure-sensitive adhesive sheet 1 is used, and are peeled off when the temperature-sensitive pressure-sensitive adhesive sheet 1 (pressure-sensitive adhesive layer 11) is used. . In the temperature-sensitive adhesive sheet 1 according to this embodiment, one or both of the release sheets 12a and 12b are not necessarily required.

  Examples of the release sheets 12a and 12b include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, and polybutylene. Terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluorine A resin film or the like is used. These crosslinked films are also used. Furthermore, these laminated films may be sufficient.

  It is preferable that the peeling surface (especially the surface in contact with the pressure-sensitive adhesive layer 11) of the release sheets 12a and 12b is subjected to a peeling treatment. Examples of the release agent used for the release treatment include alkyd, silicone, fluorine, unsaturated polyester, polyolefin, and wax release agents. Of the release sheets 12a and 12b, one release sheet is preferably a heavy release release sheet having a high release force, and the other release sheet is preferably a light release release sheet having a low release force.

  Although there is no restriction | limiting in particular about the thickness of release sheet 12a, 12b, Usually, it is about 20-150 micrometers.

2. Production of Temperature-Sensitive Adhesive Sheet As a production example of the temperature-sensitive adhesive sheet 1, a case where the above-mentioned adhesive composition P is used will be described. On the release surface of one release sheet 12a (or 12b), a coating solution of the adhesive composition P is applied, heat-treated to thermally crosslink the adhesive composition P, and a coating layer is formed. The release surface of the other release sheet 12b (or 12a) is superimposed on the layer. When a curing period is required, a curing period is set, and when the curing period is unnecessary, the coating layer becomes the pressure-sensitive adhesive layer 11 as it is. Thereby, the said thermosensitive adhesive sheet 1 is obtained. The conditions for the heat treatment and curing are as described above.

  For example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like can be used as a method for applying the coating solution of the adhesive composition P.

3. Use of Temperature-Sensitive Adhesive Sheet As described above, the temperature-sensitive adhesive sheet 1 according to this embodiment is a device such as an optical member or an electronic member as a workpiece, preferably a flexible device, particularly preferably a temperature-sensitive adhesive sheet 1. The flexible device having a smooth contact surface with the pressure-sensitive adhesive layer 11 is preferably used for fixing to a substrate during processes such as processing, lamination, and inspection. In addition, after completion | finish of said process, a workpiece | work is peeled from a board | substrate.

  In FIG. 2, sectional drawing of the laminated body 4 showing the use condition of the temperature sensitive adhesive sheet 1 is shown. The laminated body 4 which concerns on this embodiment laminates | stacks the flexible device 2 as a workpiece | work, the adhesive layer 11 of the thermosensitive adhesive sheet 1, and the board | substrate 3 in that order. In the laminate 4, the flexible device 2 is firmly fixed to the substrate 3 through the pressure-sensitive adhesive layer 11 in normal temperature and high temperature processes, and therefore the process can be performed without any problem.

  When said process is complete | finished, the adhesive layer 11 (or flexible device 2 and board | substrate 3) is cooled to 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 more preferably −50 ° C. or higher and −30 ° C. or lower. By cooling to such a temperature, the adhesive force of the pressure-sensitive adhesive layer 11 is remarkably reduced, whereby the flexible device 2 can be easily peeled from the substrate 3.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

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

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples etc.

[Example 1]
1. Preparation of (meth) acrylic acid ester 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 by a solution polymerization method to obtain (meth) acrylic acid ester. A polymer (A) was prepared. When the molecular weight of this (meth) acrylic acid ester polymer (A) was measured by the method described later, it was a weight average molecular weight (Mw) of 800,000.

2. Preparation of adhesive composition 100 parts by mass of the (meth) acrylic acid ester polymer (A) obtained in Step 1 above (converted to a solid content; the same applies hereinafter) and aluminum trisacetylacetonate as a crosslinking agent (B) 1.0 part by mass, polyrotaxane compound (C) (linear molecule: polyethylene glycol, cyclic molecule: α-cyclodextrin having a hydroxypropyl group and a caprolactone chain (low-temperature crystallization side chain), block group: adamantane group, 20 mass parts of weight average molecular weight (Mw) 700,000) were mixed, fully stirred, and diluted with methyl ethyl ketone to obtain a coating solution of an adhesive composition.

3. Production of pressure-sensitive adhesive sheet Peeling of a heavy-peelable release sheet (product name "SP-PET752150", manufactured by Lintec Corporation), in which one side of a polyethylene terephthalate film was subjected to a release treatment with a silicone-based release agent The treated surface was applied with a knife coater. And the application layer was heat-processed at 90 degreeC for 1 minute (s), and the application layer was formed.

  Next, a light release type release sheet (product name “SP-PET382120”, manufactured by Lintec Corporation) in which the coating layer on the heavy release type release sheet obtained above and one side of the polyethylene terephthalate film were release-treated with a silicone-based release agent Are bonded so that the release-treated surface of the light release-type release sheet is in contact with the coating layer, and is cured for 7 days under the conditions of 23 ° C. and 50% RH, whereby a pressure-sensitive adhesive layer having a thickness of 20 μm is obtained. A pressure-sensitive adhesive sheet having a constitution of heavy release type release sheet / pressure-sensitive adhesive layer (thickness: 20 μm) / light release type release sheet was prepared. The thickness of the pressure-sensitive adhesive layer is a value measured using a constant pressure thickness measuring instrument (manufactured by Teclock, product name “PG-02”) in accordance with JIS K7130.

Here, Table 1 shows each formulation (solid content converted value) of the adhesive composition when the (meth) acrylic acid ester polymer (A) is 100 parts by mass (solid content converted value). Details of the abbreviations and the like described in Table 1 are as follows.
[(Meth) acrylic acid ester polymer (A)]
BA: n-butyl acrylate 2EHA: 2-ethylhexyl acrylate MA: methyl acrylate AA: acrylic acid

[Examples 2-6, Comparative Examples 1-4]
The type and ratio of each monomer constituting the (meth) acrylic acid ester polymer (A), the weight average molecular weight (Mw) of the (meth) acrylic acid ester polymer (A), the blending amount of the crosslinking agent (B), and A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the blending amount of the polyrotaxane compound (C) was changed as shown in Table 1.

Here, the above-mentioned weight average molecular weight (Mw) is a polystyrene-reduced weight average molecular weight measured under the following conditions (GPC measurement) using gel permeation chromatography (GPC).
<Measurement conditions>
GPC measurement device: manufactured by Tosoh Corporation, HLC-8020
GPC column (passed in the following order): TSK guard column HXL-H manufactured by Tosoh Corporation
TSK gel GMHXL (× 2)
TSK gel G2000HXL
・ Measurement solvent: Tetrahydrofuran ・ Measurement temperature: 40 ° C.

[Test Example 1] (Measurement of glass transition temperature)
The glass transition temperature (Tg) of the (meth) acrylic acid ester 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 measured at a temperature rising / falling rate of 20 ° C / min. The results are shown in Table 1.

[Test Example 2] (Measurement of storage elastic modulus)
A plurality of pressure-sensitive adhesive layers of the pressure-sensitive adhesive sheets prepared in Examples and Comparative Examples were laminated to obtain a laminate having a thickness of 3 mm. A cylindrical body (height 3 mm) having a diameter of 8 mm was punched out from the obtained laminate of the pressure-sensitive adhesive layer, and this was used as a sample.

About the said sample, based on JISK7244-6, the storage elastic modulus (MPa) was measured on condition of the following by the torsional shear method using the viscoelasticity measuring device (the REOMETRIC company make, DYNAMIC ANALAYZER). The results are shown in Table 2.
Measurement frequency: 1Hz
Measurement temperature: -20 ° C, 23 ° C, 80 ° C

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

[Test Example 3] (Measurement of adhesive strength)
The light release type release sheet was peeled from the pressure sensitive adhesive sheets prepared in Examples and Comparative Examples, and the exposed pressure sensitive adhesive layer was replaced with a polyethylene terephthalate (PET) film having an easy adhesion layer (product name “PET A4300”, manufactured by Toyobo Co., Ltd.). The laminate was bonded to an easy-adhesion layer having a thickness of 100 μm to obtain a laminate of release sheet / adhesive layer / PET film. The obtained laminate was cut into a width of 25 mm and a length of 100 mm, and this was used as a sample.

Autoclave manufactured by Kurihara Seisakusho Co., Ltd. after peeling the heavy release release sheet from the above sample and pasting the exposed adhesive layer on soda lime glass (manufactured by Nippon Sheet Glass Co., Ltd.) in an environment of 23 ° C. and 50% RH. At 0.5 MPa and 50 ° C. for 20 minutes. Then, after leaving for 24 hours under the following conditions (a) to (c), using a tensile testing machine (Orientec, Tensilon), a peeling speed of 2.0 m / min and a peeling angle of 180 degrees. Then, the adhesive strength (adhesive strength to glass; N / 25 mm) was measured. Conditions other than those described here were measured according to JIS Z0237: 2009. The results are shown in Table 2.
(A) -20 ° C, 50% RH
(B) 23 ° C., 50% RH
(C) 80 ° C., 50% RH

  From the results obtained above, the ratio (%) of glass adhesive strength at −20 ° C. to the glass adhesive strength at 23 ° C. and the ratio (%) of glass adhesive strength at 80 ° C. to glass adhesive strength at 23 ° C. ) Was calculated. The results are shown in Table 2.

  Further, in a 23 ° C., 50% RH environment, the heavy release type release sheet was peeled from the sample, and the exposed pressure-sensitive adhesive layer was used as an adherend with a surface roughness Ra of 2. The film was affixed to the one surface of a 7 μm PET film (PET film A having a very smooth surface, thickness: 100 μm). And it pressurized for 20 minutes at 0.5 MPa and 50 degreeC with the autoclave by Kurihara Seisakusho. Then, after leaving for 24 hours under the conditions of −20 ° C. and 50% RH, the adhesive strength (against PET adhesive strength A at −20 ° C .; N / 25 mm) was measured in the same manner as described above. The results are shown in Table 2.

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

[Test Example 4] (Process evaluation)
(A) When the surface of a workpiece | work is very smooth The polyethylene terephthalate (PET) film (thickness: 100 micrometers) whose surface roughness Ra of one surface is 2.7 micrometers was prepared as a workpiece | work. The light release type release sheet was peeled from the pressure sensitive adhesive sheets prepared in Examples and Comparative Examples, and the exposed pressure sensitive adhesive layer was bonded to the one surface of the workpiece, and the heavy release type release sheet / adhesive layer / PET. A film laminate was obtained. The obtained laminate was cut into a width of 25 mm and a length of 100 mm.

  Made of Kurihara Seisakusho Co., Ltd. after peeling the heavy release release sheet from the above laminate and pasting the exposed adhesive layer on soda lime glass (manufactured by Nippon Sheet Glass Co., Ltd.) in an environment of 23 ° C. and 50% RH. The sample was pressurized in an autoclave at 0.5 MPa and 50 ° C. for 20 minutes, and this was used as a sample. The obtained sample was charged as a high temperature process under high temperature conditions of 150 ° C. and 50% RH for 30 minutes. Then, as a low temperature process, it was put into a low temperature condition of −20 ° C. and 50% RH for 1 hour, and the PET film was peeled from the pressure-sensitive adhesive layer.

In the above high-temperature process, the interface between the PET film and the pressure-sensitive adhesive layer and the interface between the pressure-sensitive adhesive layer and soda lime glass were confirmed, and high-temperature process evaluation (A) was performed according to the following criteria. The results are shown in Table 2.
A: During the high-temperature process, no floating or peeling occurred at each interface, and the PET film was firmly fixed to the soda lime glass.
〇 ... During the high temperature process, slight floating or peeling was observed at the interface.
X: Floating / peeling occurred at the interface during the high temperature process, and peeling occurred.

Moreover, in said low temperature process, the ease of peeling and the state of the interface of a PET film and an adhesive layer were confirmed, and low temperature process evaluation (A) was performed by the following references | standards. The results are shown in Table 2.
A: Peeling at the interface between the pressure-sensitive adhesive layer and the PET film was easy, and the pressure-sensitive adhesive layer adhered to the soda lime glass even after peeling.
○: Peeling at the interface between the pressure-sensitive adhesive layer and the PET film was easy, but after peeling, floating was observed at the interface between the soda lime glass and the pressure-sensitive adhesive layer.
X: Peeling at the interface between the pressure-sensitive adhesive layer and the PET film was difficult. (The laminate of the PET film and the pressure-sensitive adhesive layer was peeled off from the soda lime glass.)

(B) When the surface of a workpiece | work is comparatively smooth The PET film (thickness: 100 micrometers) whose surface roughness Ra of one surface is 60 micrometers was prepared as a workpiece | work. Using this workpiece, high-temperature and low-temperature process evaluation (B) was performed in the same manner as the above-described process evaluation (A). The results are shown in Table 2.

  As is clear from Table 2, the temperature-sensitive adhesive sheets produced in the examples exhibited excellent adhesive strength at normal temperature and high temperature, and the workpiece could be firmly fixed to the substrate during the process. Moreover, according to the said thermosensitive adhesive sheet, the workpiece | work was able to be easily peeled from the board | substrate by cooling to low temperature.

  The temperature-sensitive adhesive sheet according to the present invention is particularly suitable as a process adhesive sheet used in processes such as processing, lamination, and inspection of flexible devices.

DESCRIPTION OF SYMBOLS 1 ... Temperature sensitive adhesive sheet 11 ... Adhesive layer 12a, 12b ... Release sheet 2 ... Workpiece (flexible device)
3 ... Substrate 4 ... Laminate

Claims (14)

A temperature-sensitive adhesive sheet having at least an adhesive layer,
The adhesion to glass at −20 ° C. is less than 1.5 N / 25 mm,
The adhesive force to glass at 80 ° C. is 2.0 N / 25 mm or more,
The temperature-sensitive adhesive sheet, wherein the pressure-sensitive adhesive layer has a storage elastic modulus at -20 ° C of 1 MPa or more and 500 MPa or less.   2. The temperature-sensitive adhesive sheet according to claim 1, wherein a ratio of glass adhesive strength at −20 ° C. to glass adhesive strength at 23 ° C. is 1% or more and 40% or less.   The temperature-sensitive adhesive sheet according to claim 1 or 2, wherein the ratio of glass adhesive strength at 80 ° C to glass adhesive strength at 23 ° C is 10% or more and 300% or less.   The temperature-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer has a storage elastic modulus at 80 ° C of 0.01 MPa or more and 1 MPa or less.   The temperature-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive layer comprises a pressure-sensitive adhesive containing a polyrotaxane compound. The adhesive is
(Meth) acrylic acid ester polymer (A),
A crosslinking agent (B);
The temperature-sensitive adhesive sheet according to claim 5, which is formed from an adhesive composition containing a polyrotaxane compound (C).   The said (meth) acrylic acid ester polymer (A) contains the monomer which has a carboxy group in a molecule | numerator as a monomer unit which comprises the said polymer, The temperature sensitive adhesive of Claim 6 characterized by the above-mentioned. Sheet.   The temperature-sensitive adhesive sheet according to claim 6 or 7, wherein the crosslinking agent (B) is a metal chelate-based crosslinking agent.   It is used for the use which fixes a workpiece | work to a board | substrate through the said adhesive layer during a process, and peels the said workpiece | work from the said adhesive layer after completion | finish of a process. The temperature-sensitive adhesive sheet according to item.   The temperature-sensitive adhesive sheet according to claim 9, wherein the surface roughness Ra of the surface on the pressure-sensitive adhesive layer side of the workpiece is 0.01 µm or more and 80 µm or less.   The temperature-sensitive adhesive sheet according to claim 9 or 10, wherein the workpiece is heated to 40 ° C or higher and 200 ° C or lower during the step.   The temperature-sensitive adhesive sheet according to any one of claims 9 to 11, wherein the workpiece is a flexible device. The temperature-sensitive adhesive sheet includes two release sheets,
The temperature-sensitive adhesive sheet according to any one of claims 1 to 12, wherein the adhesive layer is sandwiched between the release sheets so as to be in contact with the release surfaces of the two release sheets. . Flexible devices,
The pressure-sensitive adhesive layer of the temperature-sensitive pressure-sensitive adhesive sheet according to any one of claims 1 to 13,
A laminate formed by laminating a substrate in that order.

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