JP7017464B2 - Temperature sensitive adhesive sheet and laminate - Google Patents

Description

The present invention relates to a temperature-sensitive pressure-sensitive adhesive sheet suitable for fixing and peeling a work, 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 processes such as processing, assembly (lamination), and inspection. Is done. Then, after the process is completed, the work is peeled off from the substrate.

As the pressure-sensitive adhesive used for the pressure-sensitive adhesive sheet as described above, for example, Patent Document 1 describes 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 comprises a crosslinked polymer obtained by adding a metal chelate compound to a copolymer obtained by polymerization and carrying out a crosslinking reaction, is disclosed.

Further, Patent Document 2 describes a (meth) acrylate having a linear alkyl group of 16 to 22, a (meth) acrylate having an alkyl group having 1 to 6 carbon atoms, and an ethylene unsaturated monomer having a carboxyl group or a hydroxyl group. A temperature-sensitive pressure-sensitive adhesive containing a side-chain crystalline polymer in which a copolymer obtained by polymerizing a weight and a reactive fluorine compound is crosslinked with a metal chelate compound and a pressure-sensitive adhesive 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 the adhesive force can be obtained by cooling. Can be reduced and the adherend can be peeled off. Further, 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, while the adherend can be fixed. By cooling, the adhesive strength is reduced and the adherend can be peeled off.

Japanese Patent No. 5600604 Japanese Patent No. 610993

By the way, as the above-mentioned device, many of them have been rigid in the past, but in recent years, flexible devices have appeared. For example, in recent years, there has been an active shift from rigid liquid crystal devices to flexible organic light emitting diode (OLED) devices as optical members. Therefore, the adhesive sheet is also required to be compatible with such a flexible device.

However, when the temperature-sensitive pressure-sensitive adhesive disclosed in Patent Documents 1 and 2 is applied to a flexible device as described above, it cannot be said that the handleability for fixing and peeling is sufficient.

The present invention has been made in view of the above circumstances, and provides a temperature-sensitive adhesive sheet having excellent handleability even when applied to a flexible device, and a laminate using the temperature-sensitive adhesive sheet. The purpose is.

In order to achieve the above object, firstly, the present invention is a temperature-sensitive pressure-sensitive adhesive sheet provided with at least an adhesive layer, which has an adhesive force against glass of 1.5 N / 25 mm or more and 22 N / 25 mm at −20 ° C. Provided is a temperature-sensitive pressure-sensitive adhesive sheet, which is less than or equal to and has an adhesive force against glass at 80 ° C. of 30 N / 25 mm or more (Invention 1).

According to the above invention (Invention 1), the work (particularly the flexible device) can be firmly fixed to the substrate by the adhesive force of the pressure-sensitive adhesive layer in the temperature-sensitive pressure-sensitive adhesive sheet in the normal temperature and high temperature steps. Can be done without problems. On the other hand, if the pressure-sensitive adhesive layer is cooled to a low temperature, the adhesive strength of the pressure-sensitive adhesive layer is reduced, whereby the work can be easily peeled off from the substrate.

In the above invention (Invention 1), the ratio of the adhesive force to glass at −20 ° C. to the adhesive force to glass at 23 ° C. is preferably 1.5% or more and 60% or less (Invention 2).

In the above inventions (Inventions 1 and 2), the ratio of the adhesive force to glass at 80 ° C. to the adhesive force to glass at 23 ° C. is preferably 15% or more and 300% or less (Invention 3).

In the above inventions (Inventions 1 to 3), the storage elastic modulus at −20 ° C. is preferably 0.06 MPa or more and 10 MPa or less (Invention 4).

In the above inventions (Inventions 1 to 4), the storage elastic modulus at 80 ° C. is preferably 0.001 MPa or more and 0.3 MPa or less (Invention 5).

In the above inventions (Inventions 1 to 5), it is preferable that the pressure-sensitive adhesive layer is made of a pressure-sensitive adhesive containing a polyrotaxane compound (Invention 6).

In the above invention (Invention 6), the pressure-sensitive adhesive is formed from a pressure-sensitive adhesive composition containing a (meth) acrylic acid ester polymer (A), a cross-linking agent (B), and a polyrotaxane compound (C). (Invention 7).

In the above invention (Invention 7), it is preferable that the (meth) acrylic acid ester polymer (A) contains a monomer having a hydroxyl group in the molecule as a monomer unit constituting the polymer (Invention 8). ..

In the above inventions (Inventions 7 and 8), the cross-linking agent (B) is preferably an isocyanate-based cross-linking agent (Invention 9).

The temperature-sensitive pressure-sensitive adhesive sheet according to the above inventions (Inventions 1 to 9) is used for fixing a work to a substrate via 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 10).

In the above invention (Invention 10), it is preferable that the surface roughness Ra of the surface on the pressure-sensitive adhesive layer side of the work is 1 μm or more and 120 μm or less (Invention 11).

In the above inventions (Inventions 10 and 11), it is preferable that the work is heated to 40 ° C. or higher and 200 ° C. or lower during the process (Invention 12).

In the above inventions (Inventions 10 to 12), it is preferable that the work is a flexible device (Invention 13).

In the above inventions (Inventions 1 to 13), the temperature-sensitive pressure-sensitive adhesive sheet includes two release sheets, and the release is such that the pressure-sensitive adhesive layer is in contact with the release surface of the two release sheets. It is preferably sandwiched between sheets (Invention 14).

Secondly, the present invention provides a laminated body in which a flexible device, the pressure-sensitive adhesive layer of the temperature-sensitive pressure-sensitive adhesive sheets (Inventions 1 to 14), and a substrate are laminated in that order (Invention 15).

The temperature-sensitive adhesive sheet according to the present invention is excellent in handleability for fixing and peeling even when applied to a flexible device. Further, the laminated body according to the present invention is excellent in handleability.

It is sectional drawing of the temperature sensitive pressure-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 preferably has a release sheet laminated on one side or both sides of the pressure-sensitive adhesive layer.

The temperature-sensitive adhesive sheet according to the present embodiment is a temperature-sensitive adhesive sheet that is used during processes such as processing, assembling (lamination), and inspection of devices such as optical members and electronic members as workpieces (workpieces). It is suitably used for fixing to a substrate via an adhesive layer. After the above step is completed, the work is peeled off from the substrate. The above-mentioned substrate is for supporting and fixing the work during the process, and also includes the concept of a pedestal and the like.

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

The substrate is not particularly limited as long as the work 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 may be performed during the above steps. Even if it is contained, it is preferable that it does not deform or change its appearance. Further, the work 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 step and in the step of peeling the work. 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, it is preferable that the surface of the substrate on the work fixing side is smooth. From these viewpoints, a glass substrate is particularly preferable as the substrate.

The temperature-sensitive adhesive sheet according to the present embodiment has an adhesive force against glass of 1.5 N / 25 mm or more and less than 22 N / 25 mm at −20 ° C. and an adhesive force against glass of 30 N / 25 mm or more at 80 ° C. Since the adhesive force against glass at −20 ° C. and 80 ° C. is the above value, the handleability for fixing and peeling is excellent even when the temperature-sensitive adhesive sheet is applied to a flexible device. Specifically, in the normal temperature and high temperature steps, the work can be firmly fixed to the substrate by the adhesive force of the pressure-sensitive adhesive layer in the temperature-sensitive pressure-sensitive adhesive sheet, and the steps can be performed without any problem. On the other hand, if the adhesive layer (or the work / substrate) is cooled to a low temperature (preferably cooled to around -20 ° C), the adhesive strength of the adhesive layer is reduced, whereby the work can be easily removed from the substrate. Can be peeled off.

Here, the adhesive strength in the present specification basically refers to the adhesive strength measured by the 180-degree peeling method according to JIS Z0237: 2009, but the measurement sample is 25 mm wide and 100 mm long, and the measured sample is used. It is attached to an adherend, pressurized at 0.5 MPa and 50 ° C. for 20 minutes, left at normal pressure, desired temperature, and 50% RH for 24 hours, and then measured at a peeling speed of 300 mm / min. It shall be. Further, the "adhesive strength against glass" in the present specification means the adhesive strength against soda lime glass.

As the work to which the temperature-sensitive pressure-sensitive adhesive sheet according to the present embodiment is applied, it is preferable that the surface of the temperature-sensitive pressure-sensitive adhesive sheet in contact with the pressure-sensitive adhesive layer is rough to some extent. Specifically, the surface roughness Ra of the surface on the pressure-sensitive adhesive layer side of the work is preferably 1 μm or more, particularly preferably 10 μm or more, and further preferably 20 μm or more as the lower limit value. .. The upper limit of the surface roughness Ra is preferably 120 μm or less, particularly preferably 100 μm or less, and further preferably 80 μm or less. When the contact surface of the work with the pressure-sensitive adhesive layer is rough to some extent in this way, when the work is cooled and peeled off, the pressure-sensitive adhesive layer is left on the substrate side and the work is easily peeled off from the pressure-sensitive adhesive layer. Can be done.

Further, it is preferable that the surface roughness Ra of the surface on the pressure-sensitive adhesive layer side of the work is larger than the surface roughness Ra of the substrate. By doing so, the work can be peeled off with the adhesive layer firmly fixed to the substrate side when the work is peeled off.

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

From the viewpoint of the above-mentioned handleability, particularly the ease of peeling of the work, the temperature-sensitive adhesive sheet according to the present embodiment preferably has an adhesive force against glass at −20 ° C. of 19 N / 25 mm or less, particularly 14 N / 25 mm. The following is preferable. The lower limit of the adhesive force against glass at -20 ° C is preferably 2.0 N / 25 mm or more, particularly 2.5 N, from the viewpoint of peeling the work while the adhesive layer is firmly fixed to the substrate side. It is preferably / 25 mm or more.

From the viewpoint of the above-mentioned handleability, particularly the work fixing during the process, the temperature-sensitive adhesive sheet according to the present embodiment has an adhesive force against glass at 80 ° C. of 30 N / 25 mm or more and 34 N / 25 mm or more. It is preferable, and it is particularly preferable that it is 38 N / 25 mm or more. If the lower limit of the adhesive force against glass at 80 ° C. is as described above, even if a heating step is included in the process, misalignment or peeling of the work is suppressed during the process, and the work is sufficiently Can be fixed. On the other hand, the upper limit of the adhesive force against glass at 80 ° C. is not particularly limited, but is preferably 180 N / 25 mm or less, particularly preferably 120 N / 25 mm or less, and further preferably 60 N / 25 mm or less. preferable.

Further, from the viewpoint of the above-mentioned handleability, particularly the work fixing during the process, the temperature-sensitive adhesive sheet according to the present embodiment preferably has an adhesive force against glass at 23 ° C. of 24 N / 25 mm or more, particularly 28 N / It is preferably 25 mm or more, and more preferably 32 N / 25 mm or more. On the other hand, the upper limit of the adhesive force against glass at 23 ° C. is preferably 100 N / 25 mm or less, particularly preferably 76 N / 25 mm or less, and further preferably 52 N / 25 mm or less from the viewpoint of reworkability. Is preferable.

In the temperature-sensitive adhesive sheet according to the present embodiment, the ratio of the adhesive force to glass at −20 ° C. to the adhesive force to glass at 23 ° C. is preferably 1.5% or more, particularly 3% or more. It is preferably present, and more preferably 6% or more. When the lower limit of the adhesive force ratio is the 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 work is peeled off by cooling to a low temperature. The adhesive strength ratio is preferably 60% or less, particularly preferably 45% or less, and further preferably 30% or less. When the upper limit of the ratio of the adhesive force is the above, the adhesive force becomes sufficiently low when cooled to a low temperature, and the peelability of the work becomes more excellent. Therefore, when the ratio of the adhesive force is within the above range, both the adhesiveness at the time of fixing the work and the easy peeling property of the work are more excellent.

Further, in the temperature-sensitive adhesive sheet according to the present embodiment, the ratio of the adhesive force to glass at 80 ° C. to the adhesive force to glass at 23 ° C. is preferably 15% or more, particularly 35% or more. It is preferably 50% or more, and more preferably 50% or more. When the lower limit 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, so that the work is prevented from being displaced or peeled off during the process. Then, the work can be fixed more sufficiently. The upper limit of the adhesive strength ratio is not particularly limited, but is preferably 300% or less, particularly preferably 250% or less, and further preferably 180% or less. Therefore, when the ratio of the adhesive force is within the above range, both the work fixing at room temperature and the work fixing at high temperature can be performed better.

The adhesive strength of the temperature-sensitive adhesive sheet according to the present embodiment to a polyethylene terephthalate (PET) film having a surface roughness Ra of 60 μm (the surface is rough to some extent) at −20 ° C. is 18 N / 25 mm or less. It is preferable, particularly preferably 15 N / 25 mm or less, and further preferably 13 N / 25 mm or less. As a result, when the surface condition of the work is equivalent to that of the PET film and the pressure-sensitive adhesive layer (or the work / substrate) is cooled to a low temperature (preferably cooled to around −20 ° C.), the work is cooled to the pressure-sensitive adhesive layer. Can be more easily peeled off from. On the other hand, the lower limit of the adhesive strength is not particularly limited, but is preferably 0.1 N / 25 mm or more, particularly preferably 0.5 N / 25 mm or more, and further preferably 1 N / 25 mm or more. preferable.

The adhesive strength of the temperature-sensitive adhesive sheet according to the present embodiment to a polyethylene terephthalate (PET) film having a surface roughness Ra of 80 μm (rough surface) at −20 ° C. is preferably 18 N / 25 mm or less. In particular, it is preferably 15 N / 25 mm or less, and more preferably 13 N / 25 mm or less. As a result, when the surface condition of the work is equivalent to that of the PET film and the pressure-sensitive adhesive layer (or the work / substrate) is cooled to a low temperature (preferably cooled to around −20 ° C.), the work is cooled to the pressure-sensitive adhesive layer. Can be more easily peeled off from. On the other hand, the lower limit of the adhesive strength is not particularly limited, but is preferably 0.1 N / 25 mm or more, particularly preferably 0.5 N / 25 mm or more, and further preferably 1 N / 25 mm or more. preferable.

The pressure-sensitive adhesive layer of the temperature-sensitive pressure-sensitive adhesive sheet according to the present embodiment preferably has a storage elastic modulus of 0.06 MPa or more, particularly preferably 0.15 MPa or more, and further 0.20 MPa at −20 ° C. The above is preferable. The storage elastic modulus is preferably 10 MPa or less, particularly preferably 7 MPa or less, and further preferably 4 MPa or less. When the storage elastic modulus is within the above range, the adhesive force against glass at −20 ° C. can easily satisfy the above-mentioned values. The method for measuring the storage elastic modulus in the present specification is as shown in a test example described later.

Further, the pressure-sensitive adhesive layer of the temperature-sensitive pressure-sensitive adhesive sheet according to the present embodiment preferably has a storage elastic modulus at 80 ° C. of 0.001 MPa or more, particularly preferably 0.005 MPa or more, and further preferably 0. It is preferably 01 MPa or more. The storage elastic modulus is preferably 0.3 MPa or less, particularly preferably 0.15 MPa or less, and further preferably 0.05 MPa or less. When the storage elastic modulus is within the above range, the adhesive force against glass at 80 ° C. (and the adhesive force against glass at 23 ° C.) can easily satisfy the above-mentioned values.

Further, the pressure-sensitive adhesive layer of the temperature-sensitive pressure-sensitive adhesive sheet according to the present embodiment preferably has a storage elastic modulus at 23 ° C. of 0.01 MPa or more, particularly preferably 0.03 MPa or more, and further preferably 0. It is preferably 05 MPa or more. The storage elastic modulus is preferably 1 MPa or less, particularly preferably 0.5 MPa or less, and further preferably 0.2 MPa or less. When the storage elastic modulus is within the above range, the adhesive force against glass at 23 ° C. (and the adhesive force against glass at 80 ° C.) can easily satisfy the above-mentioned values.

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 −20 ° C. to the storage elastic modulus at 23 ° C. is preferably 100% or more, particularly 150% or more. It is preferable, and more preferably 300% or more. As described above, the storage elastic modulus increases with cooling from 23 ° C. to −20 ° C., so that the peelability of the work becomes more excellent. The ratio of the storage elastic modulus is preferably 10,000% or less, particularly preferably 6,000% or less, and further preferably 3,000% or less. If the upper limit of the ratio of the storage elastic modulus is the above, the storage elastic modulus increases too much as the temperature is cooled from 23 ° C to -20 ° C, and the work is inadvertently peeled from the adhesive layer. It can be prevented. Therefore, when the ratio of the storage elastic modulus is within the above range, both the adhesiveness at the time of fixing the work and the peelability of the work become 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 1% or more, particularly 5% or more. It is preferably present, and more preferably 10% or more. When the lower limit of the ratio of the storage elastic modulus is the above, even if a heating step is included in the process, the adhesive force is suppressed from being excessively lowered, and the work is displaced or peeled off during the process. Can be prevented and the work can be fixed more sufficiently. The upper limit of the storage elastic modulus ratio is not particularly limited, but is preferably 80% or less, particularly preferably 60% or less, and further preferably 45% or less. When the ratio of the storage elastic modulus is within the above range, both the work fixing at room temperature and the work fixing at high temperature can be performed better.

FIG. 1 shows a specific configuration as an example of the temperature-sensitive adhesive sheet according to the present embodiment.
As shown in FIG. 1, the temperature-sensitive adhesive sheet 1 according to the embodiment has 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 composed of an adhesive layer 11 sandwiched between the release sheets 12a and 12b. The peeling surface of the release sheet in the present specification refers to a surface having peelability in the release sheet, and includes both a surface subjected to peeling treatment and a surface exhibiting peelability even without peeling treatment. ..

1. 1. Each member 1-1. Adhesive layer The adhesive constituting the adhesive layer 11 of the temperature-sensitive adhesive sheet 1 according to the present embodiment is not particularly limited as long as the above physical properties are satisfied, but is preferably a pressure-sensitive adhesive containing a polyrotaxane compound. .. The polyrotaxane compound has a mechanical bond between the cyclic molecule and the 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 obtained adhesive exhibits high stress relaxation and plasticity effects, and while maintaining high adhesive strength, it is possible to improve the cohesive force by blending a large amount of a cross-linking agent described later. It will be 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. The polyrotaxane compound into which a side chain that crystallizes at a low temperature is introduced becomes a non-adhesive component at a low temperature. In addition, the polyrotaxane compound tends to be incompatible at low temperatures 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 as a non-sticking component segregates on the surface of the pressure-sensitive adhesive layer 11, whereby the adhesive strength of the pressure-sensitive adhesive layer 11 is significantly reduced. As described above, the pressure-sensitive adhesive containing the polyrotaxane compound can exhibit high adhesive strength at room temperature and high temperature, and when cooled to a low temperature, the adhesive strength is significantly reduced. Therefore, the pressure-sensitive adhesive layer 11 made of a pressure-sensitive adhesive containing a polyrotaxane compound can easily satisfy the above-mentioned physical properties.

The type of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 11 may be, for example, any of an acrylic pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, a polyurethane-based pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and the like. Further, the pressure-sensitive adhesive may be an emulsion type, a solvent type or a solvent-free 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-mentioned physical properties and has excellent adhesive properties is preferable.

Further, the acrylic pressure-sensitive adhesive may be an active energy ray-curable adhesive or an active energy ray non-curable adhesive, but in order to exert the action of the polyrotaxane compound well, it may be used. The activation energy ray is preferably non-curable. As the active energy ray non-curable acrylic pressure-sensitive adhesive, a crosslinked type is particularly preferable, and further, a thermally crosslinked type is preferable.

The pressure-sensitive adhesive according to the present embodiment is, in particular, a pressure-sensitive composition containing a (meth) acrylic acid ester polymer (A), a cross-linking agent (B), and a polyrotaxane compound (C) (hereinafter, “sticky composition”). It is preferably a pressure-sensitive adhesive (a pressure-sensitive adhesive obtained by cross-linking the pressure-sensitive adhesive composition P) formed from (sometimes referred to as “object P”). With such an adhesive, it is easy to satisfy the above-mentioned physical properties, and since it exhibits good adhesive force and a predetermined cohesive force, it is also excellent in durability. In addition, in this specification, (meth) acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms. In addition, the concept of "polymer" shall be included in "polymer".

(1) Component (1-1) (meth) acrylic acid ester polymer (A) of the adhesive composition P
The glass transition temperature (Tg) of the (meth) acrylic acid ester polymer (A) is preferably −20 ° C. or lower, particularly preferably −25 ° C. or lower, and further preferably −30 ° C. or lower. It is preferable to have. The glass transition temperature (Tg) is preferably −100 ° C. or higher, particularly preferably −85 ° C. or higher, and more preferably −70 ° C. or higher. When the glass transition temperature (Tg) of the (meth) acrylic acid ester polymer (A) is −20 ° C. or lower, the obtained adhesive easily develops suitable viscoelasticity, and the adhesive is adhered at room temperature and high temperature. It is possible to improve both the force and the easy peeling property at low temperature. The method for measuring the glass transition temperature (Tg) is as shown in the test example described later.

The (meth) acrylic acid ester polymer (A) is a (meth) acrylic acid alkyl ester and a monomer having a reactive functional group in the molecule (monomer containing a reactive functional group) as a monomer unit constituting the polymer. And are preferably contained.

The (meth) acrylic acid ester polymer (A) can exhibit preferable tackiness by containing the (meth) acrylic acid alkyl ester as the monomer unit constituting the polymer. As the (meth) acrylic acid alkyl ester, a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms is preferable. The alkyl group may be linear or branched, or may have a cyclic structure.

The (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms has a glass transition temperature (Tg) of −30 ° C. or lower as a homopolymer (hereinafter, may be referred to as “low Tg alkyl acrylate”). ) Is preferably contained. By containing such a low Tg alkyl acrylate as a constituent monomer unit, it becomes easy to set the glass transition temperature (Tg) of the (meth) acrylic acid ester polymer (A) in the above-mentioned 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.), and 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 (Tg −40 ° C.) and the like are preferably mentioned. Above all, as a low Tg alkyl acrylate, the Tg of the homopolymer is −45 ° C. or lower from the viewpoint of further improving both the adhesive strength at normal temperature and high temperature and the easy peeling property at low temperature. It is more preferable, and it is particularly preferable that the temperature is −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 low Tg alkyl acrylate as a lower limit value of 40% by mass or more, and particularly 50% by mass or more, as a monomer unit constituting the polymer. Is preferable, and more preferably 60% by mass or more is contained. When the lower limit of the content is the above, the glass transition temperature (Tg) of the (meth) acrylic acid ester polymer (A) can be easily set within the above range.

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

The (meth) acrylic acid ester polymer (A) preferably contains a monomer having an alicyclic structure (monomer containing an alicyclic structure) as a monomer unit constituting the polymer. By containing the alicyclic structure-containing monomer, the bulky functional group can impart a cohesive force to the obtained pressure-sensitive adhesive, and the pressure-sensitive adhesive force at a high temperature can be made suitable.

The alicyclic carbon ring may have a saturated structure or an unsaturated bond. Further, the alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as two rings or three rings. The alicyclic structure preferably has 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and more preferably 7 to 12 carbon atoms.

Examples of the alicyclic structure include cyclohexyl skeleton, dicyclopentadiene skeleton, adamantan skeleton, isobornyl skeleton, cycloalkane skeleton (cycloheptane skeleton, cyclooctane skeleton, cyclononan skeleton, cyclodecane skeleton, cycloundecane skeleton, cyclododecane skeleton, etc.). , Cycloalkane skeleton (cycloheptane skeleton, cyclooctane skeleton, etc.), norbornen skeleton, norbornadiene skeleton, polycyclic skeleton (cuban skeleton, Basquetan skeleton, Hausan skeleton, etc.), spiro skeleton and the like are preferably included. Among them, those containing an isobornyl skeleton are preferable from the viewpoint of making the high-temperature adhesive force of the obtained adhesive more suitable.

As the alicyclic structure-containing monomer, a (meth) acrylic acid ester monomer containing the above skeleton is preferable, and specifically, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, (meth). Examples thereof include adamantyl acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, etc. Among them, isobornyl (meth) acrylate is preferable, and isobornyl acrylate is particularly preferable. Is preferable. These may be used individually by 1 type, or may be used in combination of 2 or more type.

The (meth) acrylic acid ester polymer (A) contains 1% by mass or more of an alicyclic structure-containing monomer as a monomer unit constituting the polymer from the viewpoint of making the high-temperature adhesive force of the obtained pressure-sensitive adhesive more suitable. It is preferably contained, particularly preferably 1.5% by mass or more, and further preferably 2% by mass or more.

Further, in the (meth) acrylic acid ester polymer (A), the content of the alicyclic structure-containing monomer is preferably 30% by mass or less, particularly 24% by mass, from the viewpoint of ensuring the blending amount of other components. % Or less, more preferably 18% 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 the reactive functional group derived from the reactive functional group-containing monomer. , Will react with the cross-linking agent (B) described later, thereby forming a cross-linked structure (three-dimensional network structure), and a pressure-sensitive adhesive having a desired cohesive force can be obtained.

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 (monomer containing a hydroxyl group) and carboxy in the molecule. Examples thereof include a monomer having a group (monomer containing a carboxy group), a monomer having an amino group in the molecule (monomer containing an amino group), and the like. One of these reactive functional group-containing monomers may be used alone, or two or more thereof may be used in combination.

Here, the cyclic molecule of the polyrotaxane compound (C) often has a reactive hydroxyl group, but both the (meth) acrylic acid ester polymer (A) and the polyrotaxane compound (C) are crosslinked with the cross-linking agent (B). By cross-linking, the cohesive force of the pressure-sensitive adhesive can be made higher. As a result, the adhesive strength can be improved especially at high temperatures, and the work can be more reliably fixed to the substrate in the high temperature process. From this point of view, it is preferable to select a cross-linking agent (B) having high reactivity with a hydroxyl group. Therefore, among the above-mentioned reactive functional group-containing monomers, it is preferable to use at least a hydroxyl group-containing monomer. Further, from the viewpoint of improving the cohesive force of the obtained pressure-sensitive adhesive, it is also preferable to use a carboxy group-containing monomer in combination with the hydroxyl group-containing monomer.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and (meth). ) Hydroxyalkyl esters of (meth) acrylic acid such as 3-hydroxybutyl acrylate and 4-hydroxybutyl (meth) acrylic acid can be mentioned. Among them, 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate are preferable, and 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate are preferable from the viewpoint of reactivity with a cross-linking agent. These may be used alone or in combination of two or more.

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. Of these, acrylic acid is preferable from the viewpoint of the polymerizable property of the (meth) acrylic acid ester polymer (A). 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 of a reactive functional group-containing monomer as a monomer unit constituting the polymer, and particularly preferably 2% by mass or more. Further, it is preferably contained in an amount of 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 24% by mass or less, and further preferably 18% by 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 higher, and the adhesive force, particularly the adhesive force at high temperature is higher.

Further, it is also preferable that the (meth) acrylic acid ester polymer (A) contains a nitrogen atom-containing monomer as a monomer unit constituting the polymer. By containing the nitrogen atom-containing monomer, the adhesion to an adherend (substrate) such as glass can be improved. Examples of the nitrogen atom-containing monomer include a monomer having an amino group, a monomer having an amide group, a monomer having a nitrogen-containing heterocycle, and the like, and among them, a monomer having a nitrogen-containing heterocycle is preferable. Further, from the viewpoint of increasing the degree of freedom of the portion derived from the nitrogen atom-containing monomer in the higher-order structure of the constituent pressure-sensitive adhesive, the nitrogen atom-containing monomer forms the (meth) acrylic acid ester polymer (A). It is preferable that no reactive unsaturated double bond group is contained other than one polymerizable group used for the polymerization of.

Examples of the monomer having a nitrogen-containing heterocycle include N- (meth) acryloylmorpholin, N-vinyl-2-pyrrolidone, N- (meth) acryloylpyrrolidone, N- (meth) acryloylpiperidin, and N- (meth) acryloyl. Pyrrolidine, N- (meth) acryloyl azylidine, aziridinyl ethyl (meth) acrylate, 2-vinylpyridine, 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N-vinylcarbazole, N-vinylphthalimide, etc. Among them, N- (meth) acryloylmorpholin, which exhibits more excellent adhesive strength, is preferable, and N-acryloylmorpholin is particularly preferable.

Examples of the nitrogen atom-containing monomer include (meth) acrylamide, N-methyl (meth) acrylamide, N-methylol (meth) acrylamide, N-tert-butyl (meth) acrylamide, and N, N-dimethyl (meth) acrylamide. , N, N-ethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-phenyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, N-vinyl Caprolactam, (meth) monomethylaminoethyl acrylate, (meth) monoethylaminoethyl acrylate, (meth) monomethylaminopropyl acrylate, (meth) monoethylaminopropyl acrylate, dimethylaminoethyl (meth) acrylate, etc. It can also be used.
The above nitrogen atom-containing monomers may be used alone or in combination of two or more.

The (meth) acrylic acid ester polymer (A) contains 1% by mass or more of a nitrogen atom-containing monomer as a monomer unit constituting the polymer from the viewpoint of improving the adhesion to an adherend such as glass. It is preferably contained in an amount of 3% by mass, more preferably 5% by mass or more. Further, the content of the nitrogen atom-containing monomer is preferably 20% by mass or less, more preferably 15% by mass or less, and 10% by mass or less from the viewpoint of ensuring the blending amount of other components. Is particularly preferred.

If desired, the (meth) acrylic acid ester polymer (A) may contain another monomer as a monomer unit constituting the polymer. As the other monomer, a monomer containing no reactive functional group is preferable so as not to inhibit the above-mentioned 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. Since it is a solution polymer, it is easy to obtain a high molecular weight polymer, and an excellent pressure-sensitive adhesive can be obtained due to its adhesive strength at high temperature.

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 (Mw) of the (meth) acrylic acid ester polymer (A) is preferably 200,000 or more, particularly preferably 300,000 or more, and further preferably 300,000 or more, from the viewpoint of easy peeling at low temperatures. Is preferably 400,000 or more. The weight average molecular weight is preferably 2.5 million or less, particularly preferably 1.8 million or less, and further preferably 1 million or less. When the upper limit of the weight average molecular weight is the above, the adhesive strength of the obtained adhesive at room temperature and high temperature becomes higher. Therefore, when the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is in the above range, the obtained pressure-sensitive adhesive is more effective in stickiness at room temperature and high temperature and easy peeling property at low temperature. It will be compatible with each other. The weight average molecular weight in the present specification is a value in terms of standard polystyrene measured by a 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) with the heating of the adhesive composition P containing the cross-linking agent (B) as a trigger to form a three-dimensional network structure. .. As a result, the cohesive force of the obtained adhesive is improved, and the adhesive force, particularly the adhesive force at a high temperature, becomes higher.

The cross-linking agent (B) may be any as long as it reacts with the reactive functional group of the (meth) acrylic acid ester polymer (A), and for example, an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, and an amine-based cross-linking agent. Agent, melamine-based cross-linking agent, aziridine-based cross-linking agent, hydrazine-based cross-linking agent, aldehyde-based cross-linking agent, oxazoline-based cross-linking agent, metal alkoxide-based cross-linking agent, metal chelate-based cross-linking agent, metal salt-based cross-linking agent, ammonium salt-based cross-linking agent. And so on. Here, when the (meth) acrylic acid ester polymer (A) contains a hydroxyl group-containing monomer as a constituent monomer unit, the cross-linking agent (B) is an isocyanate-based cross-linking agent having excellent reactivity with a hydroxyl group. It is preferable to use it. The cross-linking agent (B) may be used alone or in combination of two or more.

The isocyanate-based cross-linking agent contains at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanates, and alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate. , And their biurets, isocyanates, and adducts, which are reactants with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. Of these, trimethylolpropane-modified aromatic polyisocyanates, particularly trimethylolpropane-modified tolylene diisocyanate and trimethylolpropane-modified xylylene diisocyanate, are preferable from the viewpoint of reactivity with hydroxyl groups.

The content of the cross-linking agent (B) in the adhesive composition P is preferably 0.1 part by mass or more with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (A), and particularly 0. It is preferably 3 parts by mass or more, and more preferably 0.5 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 2 parts by mass or less. When the content of the cross-linking agent (B) is in the above range, the cohesive force of the obtained adhesive is moderately high, and the adhesive force, particularly the adhesive force at high temperature is higher.

(1-3) Polyrotaxane compound (C)
The polyrotaxane compound (C) is a compound in which a linear molecule penetrates through the openings of at least two cyclic molecules and has block groups 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 block group. That is, the linear molecule and the cyclic molecule maintain their morphology 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 (tacky composition P) according to the present embodiment contains the polyrotaxane compound (C) having such a mechanical bond, the obtained pressure-sensitive adhesive exhibits high stress relaxing property and plasticizing effect. It is possible to improve the cohesive force by blending a large amount of the cross-linking agent (B) while maintaining high adhesive strength.

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-adhesive component becomes the pressure-sensitive adhesive layer 11. The adhesive strength of the pressure-sensitive adhesive layer 11 is significantly reduced due to segregation on the surface of the pressure-sensitive adhesive layer 11. In addition, in this specification, "cyclic" of "cyclic molecule" or "cyclic oligosaccharide" means substantially "cyclic". That is, the cyclic molecule does not have to be completely ring-closed, and may have a helical structure, for example, as long as it can move on the linear molecule.

Examples of the side chain that crystallizes at a low temperature (low temperature crystallizing 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 a reactive hydroxyl group, and it is easy to introduce a side chain that crystallizes at a low temperature via the hydroxyl group. Among the above, α-cyclodextrin is particularly preferable from the viewpoint of easy exfoliation 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 pressure-sensitive adhesive (tacky composition P).

The linear molecule of the polyrotaxane compound (C) is a molecule or substance that is encapsulated in a cyclic molecule and can be integrated by a mechanical bond rather than a chemical bond such as a covalent bond, and is linear. If so, it is not particularly limited. In addition, in this specification, a "straight line" of a "linear molecule" means a substantially "straight line". 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, polyisobutylene, polyisobutylene, polybutadiene, polytetrahydrofuran, polyacrylic acid ester, 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 value, particularly preferably 10,000 or more, and further preferably 20,000 or more. preferable. When the lower limit of the number average molecular weight is equal to or higher 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 can be 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 value, particularly preferably 200,000 or less, and further preferably 100,000 or less. 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 a 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 it is a group capable of retaining the skewered form of the cyclic molecule by the linear molecule. Examples of such a group include a bulky group and an ionic group.

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

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

The content of the polyrotaxane compound (C) in the adhesive composition P according to the present embodiment is 1 part by mass or more as a lower limit with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (A). Is preferable, and in particular, it is preferably 8 parts by mass or more, and further preferably 15 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 peeled off at a low temperature. 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 as an upper limit value. When the upper limit of the content of the polyrotaxane compound (C) is as described above, the adhesive strength of the pressure-sensitive adhesive layer 11 at room temperature and high temperature becomes more excellent.

(1-4) Various Additives The tacky composition P may contain various additives usually used for acrylic pressure-sensitive adhesives, such as pressure-sensitive adhesives, antioxidants, ultraviolet absorbers, and light stabilizers, if desired. Softeners, fillers and the like can be added. The polymerization solvent and the diluting solvent described later are not included in the additives constituting the adhesive composition P.

(2) Production of Adhesive Composition P The adhesive composition P produces a (meth) acrylic acid ester polymer (A), and the obtained (meth) acrylic acid ester polymer (A) and a cross-linking agent. It can be produced by mixing (B) with the polyrotaxane compound (C) and, if desired, adding an additive.

The (meth) acrylic acid ester polymer (A) can be produced by polymerizing a mixture of monomers constituting the polymer by a usual 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, and two or more of them may be used in combination.

Examples of the polymerization initiator include azo compounds and organic peroxides, 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), 1,1'-azobis (cyclohexane1-carbonitrile), and 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, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, and di (2-ethoxyethyl) peroxy. Examples thereof include dicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxyvivarate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like.

In the above polymerization step, the weight average molecular weight of the obtained polymer can be adjusted by adding a chain transfer agent 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 mixed with a cross-linking agent (B), a polyrotaxane compound (C), and optionally additives and dilutions. By adding the solvent and mixing well, the adhesive composition P (coating solution) diluted with the solvent is obtained.

If any of the above components is in the form of a solid, or if precipitation occurs when the component is mixed with another component in an undiluted state, the component is used alone as a diluting solvent in advance. It may be dissolved or diluted and then mixed 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 methylene chloride and ethylene chloride, methanol, ethanol, propanol and 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 and viscosity of the coating solution prepared in this manner may be any range as long as it can be coated, and may be appropriately selected depending on the situation. For example, the adhesive composition P is diluted to a concentration of 10 to 60% by mass. It should be noted that the addition of a diluting solvent or the like is not a necessary condition when obtaining the coating solution, and the diluting solvent may not be added as long as the adhesive composition P has a viscosity that allows coating. In this case, the adhesive composition P becomes a coating solution using the polymerization solvent of the (meth) acrylic acid ester polymer (A) as it is as a diluting solvent.

(3) Formation of Adhesive Layer The adhesive layer 11 can be formed by cross-linking the applied adhesive composition P. The cross-linking of the adhesive composition P is preferably carried out by heat treatment. In addition, this heat treatment can also be combined with the drying treatment after the application of the adhesive composition P.

The heating temperature of the heat treatment is preferably 50 to 150 ° C, particularly preferably 70 to 120 ° C. The heating time is preferably 10 seconds to 10 minutes, and 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 above heat treatment (and curing), the (meth) acrylic acid ester polymer (A) (and the polyrotaxane compound (C)) is satisfactorily crosslinked via the crosslinking agent (B).

(4) Thickness of Adhesive Layer The thickness of the adhesive layer 11 (value measured according to JIS K7130) in the temperature-sensitive adhesive sheet 1 according to the present embodiment is preferably 5 μm or more as a lower limit. In particular, it is preferably 10 μm or more, and more preferably 15 μm or more. When the lower limit of the thickness of the pressure-sensitive adhesive layer 11 is the above, the 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 of the thickness of the pressure-sensitive adhesive layer 11 is the above, the peelability at a low temperature 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. Peeling Sheets The peeling sheets 12a and 12b protect the pressure-sensitive adhesive layer 11 until the temperature-sensitive adhesive sheet 1 is used, and are peeled off when the temperature-sensitive pressure-sensitive adhesive sheet 1 (adhesive layer 11) is used. .. In the temperature-sensitive adhesive sheet 1 according to the present embodiment, one or both of the release sheets 12a and 12b are not always necessary.

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. Telephthalate 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. In addition, these crosslinked films are also used. Further, these laminated films may be used.

It is preferable that the peeling surface (particularly the surface in contact with the pressure-sensitive adhesive layer 11) of the peeling sheets 12a and 12b is subjected to a peeling treatment. Examples of the release agent used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. Of 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. 2. Production of Temperature Sensitive Adhesive Sheet As an example of production of the temperature sensitive adhesive sheet 1, the case where the adhesive composition P is used will be described. The coating liquid of the adhesive composition P is applied to the peeling surface of one of the release sheets 12a (or 12b), heat-treated to heat-crosslink the adhesive composition P to form a coating layer, and then the coating thereof. The peeling surface of the other peeling sheet 12b (or 12a) is superposed on the layer. When the curing period is required, the curing period is set, and when the curing period is not required, the coating layer becomes the adhesive layer 11 as it is. As a result, the temperature-sensitive adhesive sheet 1 can be obtained. The conditions for heat treatment and curing are as described above.

As a method for applying the coating liquid of the adhesive composition P, 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 and the like can be used.

3. 3. Use of Temperature Sensitive Adhesive Sheet As described above, the temperature sensitive adhesive sheet 1 according to the present embodiment is a device such as an optical member or an electronic member as a work, preferably a flexible device, and particularly preferably a temperature sensitive adhesive sheet 1. A flexible device whose contact surface with the pressure-sensitive adhesive layer 11 is rough to some extent is suitably used for fixing to a substrate during processes such as processing, laminating, and inspection. After the above steps are completed, the work is peeled off from the substrate.

FIG. 2 shows a cross-sectional view of the laminated body 4 showing the usage state of the temperature-sensitive adhesive sheet 1. The laminated body 4 according to the present embodiment is formed by laminating the flexible device 2 as a work, the pressure-sensitive adhesive layer 11 of the temperature-sensitive pressure-sensitive adhesive sheet 1, and the substrate 3 in that order. In the laminated body 4, the flexible device 2 is firmly fixed to the substrate 3 via the pressure-sensitive adhesive layer 11 in the normal temperature and high temperature steps, so that the step can be performed without any problem.

When the above steps are completed, the pressure-sensitive adhesive layer 11 (or the flexible device 2 / 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 such a temperature, the adhesive strength of the pressure-sensitive adhesive layer 11 is significantly reduced, whereby the flexible device 2 can be easily peeled off from the substrate 3.

The embodiments described above are described for facilitating the understanding of the present invention, and are 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, either or both of the release sheets 12a and 12b in the temperature-sensitive adhesive sheet 1 may be omitted.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]
1. 1. Preparation of (meth) Acrylic Acid Ester Polymer (A) 65 parts by mass of 2-ethylhexyl acrylate, 15 parts by mass of isobornyl acrylate, 5 parts by mass of N-acryloyl morpholine, and 15 parts by mass of 2-hydroxyethyl acrylate. Copolymerization was carried out legally to prepare a (meth) acrylic acid ester polymer (A). When the molecular weight of this (meth) acrylic acid ester polymer (A) was measured by the method described later, the weight average molecular weight (Mw) was 600,000.

2. 2. Preparation of Adhesive Composition 100 parts by mass (solid content conversion value; the same applies hereinafter) of the (meth) acrylic acid ester polymer (A) obtained in the above step 1 and a trimethylol propane-modified bird as a cross-linking agent (B). Range isocyanate (manufactured by Toyochem, product name "BHS8515") 0.5 parts by mass and polyrotaxane compound (C) (linear molecule: polyethylene glycol, cyclic molecule: hydroxypropyl group and caprolactone chain (low temperature crystallized side chain)) Α-Cyclodextrin with, block group: adamantan group, weight average molecular weight (Mw) 700,000) 15 parts by mass is mixed, stirred well, and diluted with methyl ethyl ketone to form a coating solution of the tacky composition. Got

3. 3. Manufacture of Adhesive Sheet Peeling of a heavy release type release sheet (manufactured by Lintec Corporation, product name "SP-PET752150") in which one side of a polyethylene terephthalate film is peeled off with a silicone-based release agent from the coating solution of the obtained adhesive composition. The treated surface was coated with a knife coater. Then, the coated layer was heat-treated at 90 ° C. for 1 minute to form a coated layer.

Next, a light release type release sheet (manufactured by Lintec Corporation, product name "SP-PET382120") in which the coating layer on the heavy release type release sheet obtained above and one side of the polyethylene terephthalate film were peeled off with a silicone-based release agent). The adhesive layer having a thickness of 20 μm was formed by laminating the light peeling type peeling sheet so that the peeled surface of the light peeling type peeling sheet was in contact with the coating layer and curing it under the conditions of 23 ° C. and 50% RH for 7 days. A pressure-sensitive adhesive sheet having a structure, that is, a heavy-release type release sheet / a pressure-sensitive adhesive layer (thickness: 20 μm) / a light-release type release sheet, was produced. The thickness of the pressure-sensitive adhesive layer is a value measured using a constant pressure thickness measuring device (manufactured by Teclock Co., Ltd., product name "PG-02") in accordance with JIS K7130.

Here, Table 1 shows each formulation (solid content conversion value) of the adhesive composition when the (meth) acrylic acid ester polymer (A) is 100 parts by mass (solid content conversion value). The details of the abbreviations and the like shown in Table 1 are as follows.
[(Meta) acrylic acid ester polymer (A)]
BA: n-butyl acrylate 2EHA: 2-ethylhexyl acrylate IBXA: isobornyl acrylate ACMO: N-acryloylmorpholin HEA: 2-hydroxyethyl acrylate HPA: 2-hydroxypropyl acrylate AA: acrylic acid
[Crosslinking agent (B)]
TDI: Trimethylolpropane-modified tolylene diisocyanate (manufactured by Toyochem, product name "BHS8515")
XDI: Trimethylolpropane-modified xylylene diisocyanate (manufactured by Mitsui Takeda Pharmaceutical Co., Ltd., product name "Takenate D110N")

[Examples 2 to 7, Comparative Examples 1 to 3]
Types and proportions of each monomer constituting the (meth) acrylic acid ester polymer (A), weight average molecular weight (Mw) of the (meth) acrylic acid ester polymer (A), type and blending amount of the cross-linking agent (B). , And the amount of the polylotaxane compound (C) blended as shown in Table 1, but the pressure-sensitive adhesive sheet was produced in the same manner as in Example 1.

Here, the above-mentioned weight average molecular weight (Mw) is a polystyrene-equivalent weight average molecular weight measured under the following conditions (GPC measurement) using gel permeation chromatography (GPC).
<Measurement conditions>
-GPC measuring device: HLC-8020 manufactured by Tosoh Corporation
-GPC column (passed in the following order): TSK guard volume HXL-H manufactured by Tosoh Corporation
TSK gel GMHXL (x2)
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 by a differential scanning calorimetry device (manufactured by T.A. Instruments Japan, Inc., product name "DSC". Q2000 ”) was used to measure the temperature rise / fall at a rate of 20 ° C./min. The results are shown in Table 1.

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

The storage elastic modulus (MPa) of the above sample was measured by a torsional shear method using a viscoelasticity measuring instrument (DYNAMIC ANALAYZER, manufactured by REOMETRIC) in accordance with JIS K7244-6 under the following conditions. 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 is peeled off from the adhesive sheets produced in Examples and Comparative Examples, and the exposed adhesive layer is a polyethylene terephthalate (PET) film having an easy adhesive layer (manufactured by Toyo Spinning Co., Ltd., product name "PET A4300", It was bonded to an easy-adhesive layer having a thickness (thickness: 100 μm) to obtain a laminate of a 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.

In an environment of 23 ° C. and 50% RH, the heavy release type release sheet is peeled off from the above sample, the exposed adhesive layer is attached to soda lime glass (manufactured by Nippon Sheet Glass), and then an autoclave manufactured by Kurihara Seisakusho Co., Ltd. Pressurized at 0.5 MPa and 50 ° C. for 20 minutes. Then, after leaving it for 24 hours under the following conditions (a) to (c), adhesion is performed under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 degrees using a tensile tester (Tencilon manufactured by Orientec). The force (adhesion to glass; N / 25 mm) was measured. Conditions other than those described here were measured in accordance with 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 the adhesive force to the glass at -20 ° C to the adhesive force to the glass at 23 ° C (%) and the ratio of the adhesive force to the glass to the glass at 23 ° C (%). ) Was calculated. The results are shown in Table 2.

Further, in an environment of 23 ° C. and 50% RH, the heavy release type release sheet was peeled off from the above sample, and the exposed adhesive layer was used as an adherend, and the surface roughness Ra of one surface was 60 μm. It was attached to one of the above surfaces of a certain PET film (PET film A having a surface rough to some extent, thickness: 200 μm). Then, the pressure was increased at 0.5 MPa and 50 ° C. for 20 minutes in an autoclave manufactured by Kurihara Seisakusho. Then, after leaving it for 24 hours under the condition of −20 ° C. and 50% RH, the adhesive strength (adhesive strength against PET at −20 ° C. A; N / 25 mm) was measured in the same manner as described above. The results are shown in Table 2.

Further, using a PET film having a surface roughness Ra of one surface of 80 μm (PET film B having a rough surface, thickness: 200 μm) as an adherend, the adhesive strength (at −20 ° C.) is the same as described above. The adhesive force against PET B; N / 25 mm) was measured. The results are shown in Table 2.

[Test Example 4] (Process evaluation)
(A) When the surface of the work is rough to some extent As the work, a polyethylene terephthalate (PET) film (thickness: 200 μm) having a surface roughness Ra of one surface of 60 μm was prepared. The light release type release sheet is peeled off from the adhesive sheets produced in Examples and Comparative Examples, and the exposed adhesive layer is attached to one of the above surfaces of the work, and the heavy release type release sheet / adhesive layer / PET is attached. A laminate of films was obtained. The obtained laminate was cut into a width of 25 mm and a length of 100 mm.

In an environment of 23 ° C. and 50% RH, the heavy release type release sheet is peeled off from the above laminate, and the exposed adhesive layer is attached to soda lime glass (manufactured by Nippon Sheet Glass Co., Ltd.) and then manufactured by Kurihara Seisakusho Co., Ltd. Pressurization was performed at 0.5 MPa and 50 ° C. for 20 minutes in an autoclave, 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 off from the pressure-sensitive adhesive layer.

In the above high-temperature process, the state of the interface between the PET film and the pressure-sensitive adhesive layer and the state of the interface between the pressure-sensitive adhesive layer and soda lime glass were confirmed, and the high-temperature process was evaluated according to the following criteria. The results are shown in Table 2.
◎… 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 / peeling was observed at the interface.
×: During the high temperature process, floating / peeling occurred at the interface and peeling occurred.

Further, in the above low temperature process, the ease of peeling and the state of the interface between the PET film and the pressure-sensitive adhesive layer were confirmed, and the low temperature process was evaluated according to the following criteria. The results are shown in Table 2.
⊚ ... The adhesive layer was easily peeled off at the interface between the pressure-sensitive adhesive layer and the PET film, and the pressure-sensitive adhesive layer adhered to the soda lime glass even after the peeling.
〇… Peeling was easy at the interface between the pressure-sensitive adhesive layer and the PET film, but after peeling, floating was observed at the interface between the soda lime glass and the pressure-sensitive adhesive layer.
Δ: Peeling was possible at the interface between the pressure-sensitive adhesive layer and the PET film, but after peeling, floating or peeling was noticeably observed at the interface between the soda lime glass and the pressure-sensitive adhesive layer.
X ... It was difficult to peel off at the interface between the pressure-sensitive adhesive layer and the PET film. (The laminate of the PET film and the adhesive layer has peeled off from the soda lime glass.)

(B) When the surface of the work is a rough surface A PET film (thickness: 200 μm) having a surface roughness Ra of one surface of 80 μm was prepared as the work. Using this work, high temperature and low temperature process evaluation (B) was performed in the same manner as the above process evaluation (A). The results are shown in Table 2. For the pressure-sensitive adhesive sheets of Comparative Examples 2 and 3, the low-temperature process evaluation (B) was not performed because the high-temperature process evaluation (A) was x.

As is clear from Table 2, the temperature-sensitive adhesive sheet produced in the examples exhibited excellent adhesive strength at room temperature and high temperature, and the work could be firmly fixed to the substrate during the process. Further, according to the temperature-sensitive adhesive sheet, the work could be easily peeled off from the substrate by cooling to a 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, laminating, and inspection of flexible devices.

1 ... Temperature-sensitive adhesive sheet 11 ... Adhesive layer 12a, 12b ... Peeling sheet 2 ... Work (flexible device)
3 ... Substrate 4 ... Laminated body

Claims (12)

A temperature-sensitive adhesive sheet with at least an adhesive layer,
Adhesive strength against glass at -20 ° C is 1.5 N / 25 mm or more and less than 22 N / 25 mm.
Adhesive strength against glass at 80 ° C. is 30 N / 25 mm or more ,
The adhesive constituting the adhesive layer is
(Meta) acrylic acid ester polymer (A) and
Crosslinking agent (B) and
With polyrotaxane compound (C)
It is formed from an adhesive composition containing
It is used for fixing the work to the substrate via the pressure-sensitive adhesive layer during the process and peeling the work from the pressure-sensitive adhesive layer after the process is completed.
A temperature-sensitive adhesive sheet characterized by this. The temperature-sensitive adhesive sheet according to claim 1, wherein the ratio of the adhesive force to glass at −20 ° C. to the adhesive force to glass at 23 ° C. is 1.5% or more and 60% or less. The temperature-sensitive adhesive sheet according to claim 1 or 2, wherein the ratio of the adhesive force to glass at 80 ° C. to the adhesive force to glass at 23 ° C. is 15% or more and 300% or less. The temperature-sensitive pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the storage elastic modulus at −20 ° C. is 0.06 MPa or more and 10 MPa or less. The temperature-sensitive pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the storage elastic modulus at 80 ° C. is 0.001 MPa or more and 0.3 MPa or less. The invention according to any one of claims 1 to 5, wherein the (meth) acrylic acid ester polymer (A) contains a monomer having a hydroxyl group in the molecule as a monomer unit constituting the polymer. The temperature-sensitive adhesive sheet described. The temperature-sensitive pressure-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the cross-linking agent (B) is an isocyanate-based cross-linking agent. The temperature-sensitive pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein the surface roughness Ra of the surface on the pressure-sensitive adhesive layer side of the work is 1 μm or more and 120 μm or less. The temperature-sensitive pressure-sensitive adhesive sheet according to any one of claims 1 to 8, wherein the work is heated to 40 ° C. or higher and 200 ° C. or lower during the process. The temperature-sensitive adhesive sheet according to any one of claims 1 to 9 , wherein the work is a flexible device. The temperature-sensitive adhesive sheet comprises two release sheets.
The temperature-sensitive adhesive sheet according to any one of claims 1 to 10 , wherein the pressure-sensitive 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 and
The pressure-sensitive adhesive layer according to any one of claims 1 to 11 and the pressure-sensitive adhesive layer.
A laminated body in which substrates are laminated in that order.

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