JP6240623B2 - Double-sided pressure-sensitive adhesive sheet and peeling method - Google Patents

Description

  The present invention relates to a double-sided pressure-sensitive adhesive sheet and a peeling method.

Conventionally, a double-sided pressure-sensitive adhesive sheet used for surface bonding between objects is known. The double-sided PSA sheet is generally configured by laminating a light release film having a relatively low peeling force and a heavy release film having a relatively high peeling force on both sides of an adhesive layer.
In recent years, the use of this double-sided pressure-sensitive adhesive sheet has been expanding, and it is also used as a member for various optical applications. For example, the touch panel is a laminated body in which members such as a transparent conductive film are laminated, and a double-sided pressure-sensitive adhesive sheet is used to join the members.
Various techniques have been proposed for such a double-sided pressure-sensitive adhesive sheet. For example, in Patent Document 1, an adhesive layer is sandwiched between a light release sheet (light release film) and a heavy release sheet (heavy release film). A pressure-sensitive adhesive sheet is disclosed in which the peel strength at the interface is controlled within a predetermined range. It is shown that this pressure-sensitive adhesive sheet has an effect such that crying separation is difficult to occur.

JP 2013-166684 A

On the other hand, various properties are required for the double-sided PSA sheet.
For example, as described in Patent Document 1 described above, it is required that the occurrence of crying is suppressed. Further, from the viewpoint of durability of various devices such as a touch panel, the adhesive layer in the adhesive sheet is required to have excellent adhesion. In addition, it is also required that the release film can be more easily peeled from the viewpoint of improving handleability. Furthermore, since the pressure-sensitive adhesive sheet may be stored for a long time, it is required that peeling does not occur between the release film and the pressure-sensitive adhesive layer even after long-term storage from the viewpoint of handleability. That is, it is required that the adhesive force between the adhesive layer and the release film has little change with time.
On the other hand, the pressure-sensitive adhesive sheet of the prior art (for example, Patent Document 1) cannot satisfy all the above-mentioned requests at the same time, and further improvement is necessary.

  In view of the above circumstances, the present invention makes it difficult for crying separation to occur, it is difficult for peeling to occur between the release film and the adhesive layer even after long-term storage, and the release film can be easily peeled off, and the release film is peeled off. It aims at providing the double-sided adhesive sheet in which the back adhesion layer shows the outstanding adhesiveness.

As a result of intensive studies on the above problems, the present inventors have found that the above problems can be solved by controlling the characteristics of the pressure-sensitive adhesive layer and the characteristics of the surface of the release film, and have reached the present invention.
That is, the present inventors have found that the above problem can be solved by the following configuration.

(1) A double-sided pressure-sensitive adhesive sheet having a heavy release film, an adhesive layer, and a light release film in this order,
The temperature dependency of the dielectric constant of the adhesive layer determined from the temperature dependency evaluation test described later is 20% or less,
The value of the dispersion component of the surface free energy on the adhesive layer side surface of the heavy release film and the light release film is 11.0 to 13.0 mN / mm,
A double-sided pressure-sensitive adhesive sheet, wherein the difference between the value of the dispersion component of the surface free energy of the heavy release film and the value of the dispersion component of the surface free energy of the light release film is 0.2 mN / mm or more.
(2) The double-sided pressure-sensitive adhesive sheet according to (1), wherein an acrylic pressure-sensitive adhesive is contained in the pressure-sensitive adhesive layer.
(3) The pressure-sensitive adhesive layer is a layer obtained by curing a curable pressure-sensitive adhesive composition containing a (meth) acrylate monomer, a polymerization initiator, a tackifier, and a rubber component, (1) or The double-sided pressure-sensitive adhesive sheet according to (2).
(4) The double-sided pressure-sensitive adhesive sheet according to (3), wherein the curable pressure-sensitive adhesive composition further contains a chain transfer agent.
(5) The double-sided pressure-sensitive adhesive sheet according to any one of (1) to (4), wherein the temperature dependency is 10% or less.
(6) A peeling method for peeling the heavy release film or the light release film from the double-sided pressure-sensitive adhesive sheet according to any one of (1) to (5), wherein the release speed when peeling the heavy release film or the light release film Is a peeling method in which is 40 m / min or more or 0.25 m / min or less.
(7) The peeling method according to (6), wherein the peeling speed is 80 m / min or more, or the peeling speed is 0.15 m / min or less.
(8) A peeling method for peeling the heavy release film or the light release film from the double-sided pressure-sensitive adhesive sheet according to any one of (1) to (5), wherein the pressure sensitive adhesive layer is peeled off when the heavy release film or the light release film is peeled off. The peeling method whose temperature is 35 degreeC or more or 5 degrees C or less.
(9) The peeling method according to (8), wherein the temperature is 40 ° C. or higher, or the temperature is −5 ° C. or lower.

  According to the present invention, it is difficult for crying separation to occur, peeling is unlikely to occur between the release film and the adhesive layer even after long-term storage, and the release film can be easily peeled off, and the adhesive layer after the release film is peeled off Can provide a double-sided PSA sheet exhibiting excellent adhesion.

It is sectional drawing of the one aspect | mode of the double-sided adhesive sheet of this invention. It is the schematic of the sample for evaluation used in a temperature dependence evaluation test. It is an example of the result of a temperature dependence evaluation test.

Below, the double-sided adhesive sheet of this invention is demonstrated.
In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
Features of the double-sided pressure-sensitive adhesive sheet of the present invention include controlling the temperature dependence of the relative dielectric constant of the pressure-sensitive adhesive layer and controlling the dispersion component of the surface free energy on the surface of the release film. The temperature dependency will be described in detail later, but the low temperature dependency of the adhesive layer indicates that the adhesive layer exhibits a more hydrophobic property. The inventor combined a pressure-sensitive adhesive layer exhibiting a specific temperature dependence, that is, a more hydrophobic property, and a release film whose surface characteristics were controlled within a range of a dispersion component of a predetermined surface free energy. It has been found that desired characteristics can be obtained.

Hereinafter, the suitable aspect of the double-sided adhesive sheet of this invention is demonstrated with reference to drawings.
In FIG. 1, sectional drawing of the embodiment of the double-sided adhesive sheet of this invention is shown. The double-sided pressure-sensitive adhesive sheet 10 is a sheet in which a heavy release film 12, an adhesive layer 14, and a light release film 16 are laminated in this order. In addition, a base material is not contained in the double-sided adhesive sheet of this invention, and it corresponds to what is called a base-material-less double-sided adhesive sheet.
Below, each member is explained in full detail.

<Heavy release film and light release film>
The heavy release film and the light release film are layers disposed on both sides of the adhesive layer. The heavy release film and the light release film are films having different release forces with respect to the adhesive layer. More specifically, the light release film can be peeled from the adhesive layer with a peeling force smaller than that of the heavy release film. In this specification, “heavy peeling” and “light peeling” do not represent the magnitude of the peeling strength, but the two peeling films having a larger peeling force than the adhesive layer are heavyly peeled. A film having a smaller peeling force is referred to as a light release film.
The difference between the peel strength of the heavy release film on the adhesive layer and the peel strength of the light release film on the adhesive layer is not particularly limited. The peel strength of the release film is preferably 1.5 times or more, and more preferably 2.0 times or more. The upper limit is not particularly limited, but is often 6.0 times or less.
In addition, these peeling forces are measured based on JIS-Z0237.

The type of the heavy release film and the light release film is not particularly limited as long as the dispersion component of the surface free energy described below is in a predetermined range, but is often a resin film having a surface subjected to a release treatment.
Examples of the release treatment include application of a silicone release agent, application of a long-chain alkyl release agent, and application of a fluorine release agent.
As the resin film, a known film can be used. For example, various resin films such as a polyethylene film, a polypropylene film, a polyethylene terephthalate film, and polystyrene can be used.

The value of the dispersion component of the surface free energy on the adhesive layer side surface of the heavy release film and the light release film is 11.0 to 13.0 mN / mm, and the release film and the adhesive layer are peeled even after long-term storage. 11.2 to 12.8 mN / mm is preferable, and 11.4 to 12.6 mN / mm is more preferable in that it is less likely to occur, the release film is more easily peeled during use, or the adhesion of the adhesive layer is more excellent. preferable.
When the value of the dispersion component of the surface free energy is less than 11.0 mN / mm, peeling is likely to occur between the release film and the adhesive layer after long-term storage, and the adhesive strength of the adhesive layer is inferior. Moreover, when the value of the dispersion component of the surface free energy is more than 13.0 mN / mm, the release film is difficult to peel from the adhesive layer.
Moreover, the difference between the value of the dispersion component of the surface free energy on the surface of the pressure-sensitive adhesive layer of the heavy release film and the value of the dispersion component of the surface free energy of the surface of the pressure-sensitive adhesive layer of the light release film is 0.2 mN / mm or more. , 0.25 mN / mm or more is preferable, and 0.30 mN / mm or more is more preferable in that crying separation is less likely to occur. The upper limit is not particularly limited, but is preferably 2.0 mN / mm or less.
When the difference is less than 0.2 mN / mm, crying separation is likely to occur.

As a method of measuring the dispersion component of the surface free energy on the surface of the pressure-sensitive adhesive layer of the heavy release film and the light release film, obtain it according to the Owens and Wendt method (J. Appl. Polym. Sci., 13, 1741 (1969).). Can do.
That is, a liquid having a known surface free energy is dropped on the surface of the heavy release film (or light release film), the contact angle is measured using Drop Master-700 (manufactured by Kyowa Interface Science Co., Ltd.), and Owens. The dispersion component of the surface free energy is calculated from a calculation formula based on the and Wendt analysis.
The Owens and Wendt analysis is intended to form a surface free energy dispersion component based on the following equations (1) to (3).
Formula (1): 1 + cos θ = 2 [(γ _S ^d · γ _L ^d ) / γ _L ² ] ^1/2 +2 [(γ _S ^p · γ _L ^p ) / γ _L ² ] ^1/2
Formula (2): γ _S = γ _S ^d + γ _S ^P
Formula (3): γ _L = γ _L ^d + γ _L ^P
Where θ is the contact angle for each test liquid, γ _S ^d and γ _L ^d are the dispersion components of the surface free energy between the heavy release film (or light release film) and the test liquid, and γ _S ^p and γ _L ^p is a polar component of the surface free energy of the heavy release film (or light release film) and the test liquid, respectively.
In the present invention, water and methylene iodide are used as test liquids. The surface free energy values of water and methylene iodide used as test liquids are as follows: water: γ _L ^d = 21.8 mJm ⁻² , γ _L ^p = 51.0 mJm ⁻² , methylene iodide: γ _L ^d = 50. It is assumed that 8 mJm ⁻² and γ _L ^p = 0 mJm ⁻² are used. By introducing these numerical values into the above formulas (1) to (3) and introducing the numerical values of the contact angles using the respective test liquids into the above formula, the dispersion component γ _S ^d of the surface free energy can be calculated. it can.
In addition, as a contact angle measurement method, at 25 ° C., a test liquid is dropped on a heavy release film (or a light release film), and the waiting time from landing to measurement is 5 seconds. It is measured by the θ / 2 method in accordance with the “static drop method” described.

<Adhesive layer>
An adhesion layer is a layer arrange | positioned between a heavy release film and a light release film, and is a layer which ensures the adhesiveness between each member.
The adhesive layer has a temperature dependency of a relative dielectric constant of 20% or less obtained from a temperature dependency evaluation test described later. Among these, 15% or less is preferable, 10% or less is more preferable, 10% or less is more preferable, and 8% or less is particularly preferable in terms of better adhesion. The lower limit is not particularly limited, but is preferably as low as possible, and most preferably 0%.

The method for conducting the temperature dependence evaluation test will be described in detail below. In addition, the measurement of the dielectric constant using the impedance measurement technique at each temperature described below is generally called a capacitance method. The capacitance method is conceptually a method of forming a capacitor by sandwiching a sample between electrodes and calculating a dielectric constant from the measured capacitance value.
First, as shown in FIG. 2, the pressure-sensitive adhesive layer 18 (thickness: 100 to 500 μm) to be measured is sandwiched between a pair of aluminum electrodes 200 (electrode area: 20 mm × 20 mm), and applied at 40 ° C., 5 atm for 60 minutes. A sample for evaluation is prepared by pressure defoaming treatment.
Thereafter, the temperature of the adhesive layer in the sample was gradually increased from −40 ° C. to 80 ° C. by 20 ° C., and the capacitance was measured by impedance measurement at 1 MHz using an impedance analyzer (Agilent 4294A) at each temperature. Find C. Then, after multiplying the obtained capacitance C and the thickness T of the adhesive layer, the obtained value is used as the area S of the aluminum electrode and the dielectric constant ε ₀ (8.854 × 10 ⁻¹² F / m) of vacuum. ) To calculate the relative dielectric constant. That is, the relative permittivity is calculated by the formula (X): relative permittivity = (capacitance C × thickness T) / (area S × vacuum permittivity ε ₀ ).
More specifically, the temperature of the adhesive layer is increased stepwise so that the temperature of the adhesive layer becomes −40 ° C., −20 ° C., 0 ° C., 20 ° C., 40 ° C., 60 ° C., and 80 ° C. After leaving for 5 minutes until the temperature of the layer becomes stable, the capacitance C is obtained by impedance measurement at 1 MHz at that temperature, and the relative dielectric constant at each temperature is calculated from the obtained value.
The thickness of the pressure-sensitive adhesive layer is a value obtained by measuring the thickness of the pressure-sensitive adhesive layer at at least 5 arbitrary points and arithmetically averaging them.
Thereafter, the minimum value and the maximum value are selected from the calculated relative dielectric constants, and the ratio of the difference between the two to the minimum value is obtained. More specifically, a value (%) calculated from the formula [{(maximum value−minimum value) / minimum value} × 100] is obtained, and the value is set as the temperature dependence.

FIG. 3 shows an example of the temperature dependence evaluation test result. In FIG. 3, the horizontal axis represents temperature, and the vertical axis represents relative dielectric constant. Moreover, FIG. 3 is an example of the measurement result of 2 types of adhesion layers, one is shown by the result of a white circle and the other is a black circle.
Referring to FIG. 3, in the adhesive layer A indicated by white circles, the relative permittivity at each temperature is relatively close, and the change is small. That is, the relative dielectric constant of the adhesive layer A shows little change with temperature. The temperature dependency (%) of the pressure-sensitive adhesive layer A is selected from the formula [(A2-A1) / A1 × 100] by selecting A1 which is the minimum value of the white circle and A2 which is the maximum value in FIG. Can be sought.
On the other hand, in the adhesive layer B indicated by a black circle, as the temperature rises, the relative permittivity increases greatly, and the change is large. That is, the relative permittivity of the adhesive layer B shows a large change with temperature. Note that the temperature dependency (%) of the adhesive layer B is determined by the formula [(B2-B1) / B1 × 100] by selecting B1 which is the minimum value of the black circle and B2 which is the maximum value in FIG. Can be sought.
That is, the temperature dependence indicates the degree of change in dielectric constant with temperature. If this value is small, the change in relative dielectric constant hardly occurs from low temperature (−40 ° C.) to high temperature (80 ° C.). On the other hand, when this value is large, the relative permittivity tends to change from a low temperature (−40 ° C.) to a high temperature (80 ° C.). As will be described later, the fact that the temperature dependency is low means that the adhesive layer is more hydrophobic. In the above example, the adhesive layer A is more hydrophobic than the adhesive layer B. Represent.

The present inventors have found that the temperature dependency greatly correlates with the polarity of the adhesive layer. That is, in the case of an adhesive layer having a high polarity, the temperature dependency is increased, and in the case of an adhesive layer having a low polarity, the temperature dependency is decreased. The adhesive layer having high polarity includes a large number of polar groups such as OH groups and —CO— groups. In such an adhesive layer, since the dipole-dipole moment derived from the polar group contributes to the relative permittivity, it has been found that the relative permittivity changes greatly depending on the environmental temperature.
On the other hand, when the temperature dependency is 20% or less, the polarity of the pressure-sensitive adhesive layer is low, in other words, the pressure-sensitive adhesive layer is more hydrophobic, and there is a relationship with the surface characteristics of the heavy release film and the light release film described above. It becomes better and a desired effect is obtained.

The temperature dependence has a certain correlation with the ratio (I / O ratio) between the inorganic value (I value) and the organic value (O value) of the pressure-sensitive adhesive contained in the pressure-sensitive adhesive layer.
In the following, first, the I / O ratio will be described in detail.
The ratio (I / O ratio) between the inorganic value (I value) and the organic value (O value) is calculated by the calculation method in the organic conceptual diagram. An organic conceptual diagram was proposed by Fujita et al., And is an effective method for predicting various physicochemical properties from the chemical structure of organic compounds (written by Yoshio Koda, Organic Conceptual Diagram-Fundamentals and Applications, Sankyo Publishing) (1984)). Since the polarity of the organic compound depends on the number of carbon atoms and substituents, the inorganic value of other substituents is based on the case where the organic value of the methylene group is 20 and the inorganic value of the hydroxyl group is 100. And the organic value is determined, and the inorganic value and the organic value of the organic compound are calculated. An organic compound having a large inorganic value has high polarity, and an organic compound having a large organic value has low polarity.
The organic and inorganic values of the main groups by Fujita are summarized in Table 1 below.

As shown in Table 1 above, it can be seen that the compound having a large inorganic value mainly contains a large amount of CH ₂ . Therefore, it can be seen that a compound having a small I / O ratio is a compound having a low content of polar groups such as —OH groups and —COOR groups and mainly composed of CH ₂ (methylene group).

The present inventors have found that a compound having a small I / O ratio has a relatively low temperature dependency. The reason is that, as described above, when the adhesive contains many polarities such as carbonyl groups, the relative dielectric constant of the adhesive increases with temperature due to the dipole-dipole moment derived from these groups. Change. That is, the temperature dependency is relatively high.
On the other hand, as described above, since the compound having a small I / O ratio has a small content of polar groups, the relative dielectric constant of the pressure-sensitive adhesive hardly changes depending on the temperature, resulting in a decrease in temperature dependency.

The ratio (I / O ratio) between the inorganic value (I value) and the organic value (O value) of the adhesive used in the adhesive layer is not particularly limited, but the effect of the present invention is more excellent. 0.05-0.30 are preferable, 0.08-0.30 are more preferable, 0.12-0.28 are further more preferable, and 0.15-0.28 are especially preferable.
In addition, the organic value (O value), inorganic value (I value), and ratio (I / O ratio) of the above-mentioned pressure-sensitive adhesive can be calculated according to the technique of the book. The pressure-sensitive adhesive which is a polymer containing a repeating unit and a mixture thereof can be calculated based on the technique described in the book.
About the concrete calculation method of the above I value, O value, and I / O ratio, Honma et al. Co-authored the above "New edition organic conceptual diagram basics and application" published as an organic conceptual diagram calculation sheet for Excel (http: //www.ecosci.jp/sheet/orgs_help.html) and can be calculated using this.

Although the thickness in particular of an adhesion layer is not restrict | limited, It is preferable that it is 5-2500 micrometers, and it is more preferable that it is 20-500 micrometers. Within the above range, desired visible light transmittance can be obtained, and handling is easy.
The adhesive layer is preferably optically transparent. That is, a transparent adhesive layer is preferable. Optically transparent means that the total light transmittance is 85% or more, preferably 90% or more, and more preferably 95% or more.

The material (adhesive) constituting the adhesive layer is not particularly limited as long as the above temperature dependency is satisfied. For example, an acrylic adhesive, a rubber adhesive, a silicone adhesive, and the like can be given. Here, the acrylic pressure-sensitive adhesive is a pressure-sensitive adhesive containing a polymer ((meth) acrylic polymer) of an acrylic monomer and / or a methacrylic monomer. Although the said polymer is contained as a base polymer in the said acrylic adhesive, the other components (The tackifier mentioned later, a rubber component, etc.) may be contained.
The (meth) acrylic polymer is a concept including one or both of an acrylic polymer and a methacrylic polymer.

As a monomer ((meth) acrylate monomer) used for producing the (meth) acrylic polymer, a known material can be used as long as the adhesive layer exhibits the temperature dependency.
“(Meth) acrylate” is a concept including one or both of acrylate and methacrylate.

One preferred embodiment of the adhesive layer includes an embodiment containing an acrylic adhesive, and in particular, a (meth) acryl having a repeating unit derived from a (meth) acrylate monomer having a hydrocarbon group having at least 4 carbon atoms. The polymer is preferably contained in the adhesive layer. The (meth) acrylate monomer is a concept including one or both of an acrylate monomer and a methacrylate monomer.
Examples of the (meth) acrylate monomer having carbon number include 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, n-hexadecyl (meth) acrylate, stearyl (meth) Examples include acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and dicyclopentenyloxyethyl (meth) acrylate.
Examples of the (meth) acrylate monomer having an aliphatic hydrocarbon group having the carbon number include a (meth) acrylate monomer having a chain aliphatic hydrocarbon group having the carbon number, and a cyclic aliphatic hydrocarbon group having the carbon number. (Meth) acrylate monomers having As carbon number, 6 or more are preferable, 6-20 are more preferable, and 8-16 are more preferable.

  As one preferred embodiment of the (meth) acrylate monomer, it is preferable not to contain a polar group (excluding an ester group). When a polar group is included, the temperature dependency tends to increase. Examples of the polar group include a hydroxyl group, an amino group, a urethane group, a urea group, and a carboxylic acid group.

One preferred embodiment of the (meth) acrylic polymer is a repeating unit derived from a (meth) acrylate monomer having a chain aliphatic hydrocarbon group having 4 or more carbon atoms, and a cyclic aliphatic hydrocarbon having 4 or more carbon atoms. (Meth) acrylic polymer which has a repeating unit derived from the (meth) acrylate monomer which has group is mentioned. In addition, 6 or more are preferable, as for the suitable range of carbon number in the chain aliphatic hydrocarbon group and cyclic aliphatic hydrocarbon group in each repeating unit, 6-20 are more preferable, and 8-16 are more preferable.
The (meth) acrylic polymer includes monomers other than those described above within a range not impairing the effects of the present invention (for example, carboxylic acid group-containing (meth) acrylate (for example, acrylic acid), hydroxyl group-containing (meth) acrylate (for example, , 2-hydroxyethyl acrylate))-derived repeating units may be included.
Furthermore, the (meth) acrylic polymer may have a crosslinked structure. The method for forming the crosslinked structure is not particularly limited, and a method using a bifunctional (meth) acrylate monomer or a crosslinking agent that introduces a reactive group (for example, a hydroxyl group) into a (meth) acrylic polymer and reacts with the reactive group. The method of making it react with is mentioned. Specific examples of the latter method include a repeating unit derived from a (meth) acrylate monomer having a group having at least one active hydrogen selected from the group consisting of a hydroxyl group, a primary amino group, and a secondary amino group (meta ) A method of preparing an adhesive layer by reacting an acrylic polymer with an isocyanate-based cross-linking agent (a compound having two or more isocyanate groups).
The (meth) acrylate monomer is preferably a monofunctional (meth) acrylate monomer including one (meth) acryloyl group.

  The content of the (meth) acrylic polymer in the adhesive layer is not particularly limited, but 10 to 50% by mass with respect to the total mass of the adhesive layer in that the adhesiveness of the adhesive layer is more excellent and the effect of the present invention is more excellent. Is preferable, and 15-40 mass% is more preferable.

The adhesion layer may further contain a tackifier.
As the tackifier, those known in the field of patch or patch preparation may be appropriately selected and used. For example, petroleum resin (for example, aromatic petroleum resin, aliphatic petroleum resin, mixed aliphatic / aromatic petroleum resin, resin by C9 fraction), terpene resin (for example, α-pinene resin, β-pinene resin) , Resin obtained by copolymerizing any mixture of α pinene / β pinene / dipentene, terpene phenol copolymer, hydrogenated terpene phenol resin, aromatic modified hydrogenated terpene resin, abietic acid ester resin), rosin Resin (for example, partially hydrogenated gum rosin resin, erythritol modified wood rosin resin, tall oil rosin resin, wood rosin resin, gum rosin, rosin modified maleic acid resin, polymerized rosin, rosin phenol, rosin ester), coumarone indene resin (for example, Coumarone indene styrene copolymer).
The tackifier can be used singly or in combination of two or more, and when used in combination of two or more, for example, different types of resins may be combined, and the softening point of the same type of resin Different resins may be combined.
The content of the tackifier in the pressure-sensitive adhesive layer is not particularly limited, but is preferably 10 to 60% by mass with respect to the total mass of the pressure-sensitive adhesive layer in that the adhesiveness of the pressure-sensitive adhesive layer is more excellent and the effect of the present invention is more excellent. 20-50 mass% is more preferable.

The adhesive layer may further contain a rubber component (softening agent).
Examples of the rubber component include polyolefin or modified polyolefin. Examples of the rubber component include natural rubber, polyisobutylene, polybutadiene (modified liquid polybutadiene, polymer of 1,4-butadiene, 1,2-butadiene or a copolymer mixture thereof), hydrogenated polyisoprene, and hydrogenated polybutadiene. , Polyisoprene, polybutene, styrene butadiene copolymer, or a copolymer or polymer mixture of a combination arbitrarily selected from these groups.
In the present specification, the above polyisobutylene, polybutadiene, polyisoprene, or hydrogenated products thereof are handled as one type of polyolefin.
The content of the rubber component in the adhesive layer is not particularly limited, but 20 to 75% by mass is preferable with respect to the total mass of the adhesive layer in terms of more excellent adhesiveness of the adhesive layer and more excellent effects of the present invention. 25-60 mass% is more preferable.

As one preferred embodiment of the pressure-sensitive adhesive layer, there is a pressure-sensitive adhesive layer obtained by subjecting a curable pressure-sensitive adhesive composition containing a (meth) acrylate monomer having a (meth) acryloyl group to a curing treatment. The definition of the (meth) acrylate monomer is as described above.
One preferred embodiment of the (meth) acrylate monomer has a (meth) acrylate monomer having a chain aliphatic hydrocarbon group having 4 or more carbon atoms and a cyclic aliphatic hydrocarbon group having 4 or more carbon atoms ( A (meth) acrylate monomer is mentioned, The aspect which uses these together is more preferable.

Moreover, it is preferable that the said tackifier is contained in the said curable adhesive composition.
The content of the tackifier in the curable adhesive composition is not particularly limited, but is preferably 80 to 320 parts by mass and more preferably 120 to 270 parts by mass with respect to 100 parts by mass of the (meth) acrylate monomer.

Furthermore, the rubber component is preferably contained in the curable pressure-sensitive adhesive composition.
In addition, as a rubber component, the rubber component which has a polymeric group may be contained. That is, the curable pressure-sensitive adhesive composition may contain a rubber component having a polymerizable group and / or a rubber component having no polymerizable group. Examples of the polymerizable group include known radical polymerizable groups ((meth) acryloyl group, acrylamide group, vinyl group, styryl group, allyl group, etc.) and known cationic polymerizable groups (epoxy group, etc.). . Examples of the rubber component having a polymerizable group include one selected from the group consisting of polybutadiene, polyisoprene, polyisobutylene, hydrogenated polybutadiene, and hydrogenated polyisoprene having a (meth) acryloyl group.
Although content of the rubber component in a curable adhesive composition is not restrict | limited in particular, 70-320 mass parts is preferable with respect to 100 mass parts of (meth) acrylate monomers, and 100-280 mass parts is more preferable.

Furthermore, the curable pressure-sensitive adhesive composition preferably contains a polymerization initiator.
As the polymerization initiator, a photopolymerization initiator or a thermal polymerization initiator can be used, and a photopolymerization initiator is preferably used.
In addition, the kind in particular of photoinitiator is not restrict | limited, A well-known photoinitiator (a radical photoinitiator, a cationic photoinitiator) can be used. For example, alkynephenone photopolymerization initiator, methoxyketone photopolymerization initiator, acylphosphine oxide photopolymerization initiator, hydroxyketone photopolymerization initiator (for example, IRGACURE184; 1,2-α-hydroxyalkylphenone) Aminoketone photopolymerization initiator (for example, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one (IRGACURE (registered trademark) 907)), oxime photopolymerization initiator Is mentioned.
The content of the polymerization initiator in the curable pressure-sensitive adhesive composition is not particularly limited, but is preferably 0.1 to 25 parts by mass, and 0.1 to 20 parts by mass with respect to 100 parts by mass of the (meth) acrylate monomer. More preferred.

Furthermore, the curable pressure-sensitive adhesive composition preferably contains a chain transfer agent in terms of lowering the polymer molecular weight and lowering the elastic modulus of the pressure-sensitive adhesive layer.
The type of chain transfer agent is not particularly limited, and known chain transfer agents (for example, 1-dodecanethiol, trimethylolpropane tristhiopropionate, pentaerythritol tetrakisthiopropionate, etc.) are used.
The content of the chain transfer agent in the curable pressure-sensitive adhesive composition is not particularly limited, but is preferably 0 to 40 parts by mass and more preferably 1 to 30 parts by mass with respect to 100 parts by mass of the (meth) acrylate monomer.

The curable pressure-sensitive adhesive composition may contain a solvent as necessary. Examples of the solvent used include water, organic solvents (for example, alcohols such as methanol, ketones such as acetone, amides such as formamide, sulfoxides such as dimethyl sulfoxide, esters such as ethyl acetate, ethers, and the like. Etc.), or a mixed solvent thereof.
In addition to the above, the curable adhesive composition includes a surface lubricant, a leveling agent, an antioxidant, a corrosion inhibitor, a light stabilizer, a heat stabilizer, an ultraviolet absorber, a polymerization inhibitor, a silane coupling agent, It can be appropriately added depending on the use of various conventionally known additives such as inorganic or organic fillers, powders such as metal powders and pigments, particles and foils.

<Method for producing double-sided PSA sheet>
The method for producing the double-sided pressure-sensitive adhesive sheet is not particularly limited. For example, the double-sided adhesive film and the lightly peelable film are coated on the surface of one of the heavyly peelable film and the lightly peelable film, and the heavyly peelable film and the lightly peeled film are coated on the obtained coating film. The other side of the film is laminated, and the coating layer is cured to form an adhesive layer (application method), or the adhesive layer produced on the temporary support is either a heavy release film or a light release film. Examples of the method include transferring to the surface and laminating the other of the heavy release film and the light release film on the exposed surface of the transferred adhesive layer (transfer method).
Below, the aspect of the coating method is explained in full detail.

Examples of the method for applying the curable pressure-sensitive adhesive composition include known methods, and known application devices such as an applicator, a gravure coat, a curtain coat, a comma coater, a slot die coater, and a lip coater are used.
After application, if necessary, a drying process may be performed to remove volatile components.

After coating the curable pressure-sensitive adhesive composition on one surface of the heavy release film and the light release film to form a coating film, the other of the heavy release film and the light release film is laminated on the surface of the coating film, On the other hand, a curing process is performed.
In addition, when contacting the surface of a heavy release film and a light release film, and a coating film, the surface where the value of the dispersion component of the surface free energy mentioned above is a predetermined value is arrange | positioned at the coating film side.

Examples of the curing treatment applied to the coating film include light irradiation treatment (photocuring treatment) or heat treatment (thermosetting treatment). In particular, when the adhesive layer is formed by a photocuring treatment, the adhesive layer is relatively less likely to be deformed with time, which is preferable in terms of production suitability.
The conditions for the light irradiation treatment are not particularly limited, and an ultraviolet irradiation method in which ultraviolet rays are generated and irradiated for photocuring is preferable. Examples of the ultraviolet lamp used in such a method include a metal halide lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, a pulse type xenon lamp, a xenon / mercury mixed lamp, a low-pressure sterilization lamp, and an electrodeless lamp. Among these ultraviolet lamps, it is preferable to use a metal halide lamp or a high-pressure mercury lamp.
Although irradiation conditions vary depending on the conditions of the respective lamps, usually radiation exposure may be in the range of 20~10000mJ / cm ^2, preferably in the range of 100~3000mJ / cm ^2.
Further, in the heat treatment, a method for applying heat may be selected from appropriate methods such as an oven, a reflow furnace, and an IR heater. Furthermore, you may combine a photocuring process and a thermosetting process suitably.

  The above-mentioned double-sided pressure-sensitive adhesive sheet can be applied to various uses, and can be applied to the production of touch panels, for example.

The method for peeling the heavy release film or light release film from the double-sided pressure-sensitive adhesive sheet is not particularly limited, but zippering (a phenomenon of discontinuous peeling) hardly occurs when the heavy release film or light release film is peeled off. It is preferable that at least one of the following requirements 1 and 2 is satisfied from the point that unevenness is not easily generated on the surface of the pressure-sensitive adhesive layer from which the film has been peeled.
(Requirement 1) When peeling a heavy release film or a light release film, the peeling speed is 40 m / min or more or 0.25 m / min or less (Requirement 2) When peeling a heavy release film or a light release film, an adhesive layer The temperature is 35 ° C or higher or 5 ° C or lower

The said requirement 1 prescribes | regulates that a peeling rate is 40 m / min or more or 0.25 m / min or less when peeling a heavy peeling film or a light peeling film from a double-sided adhesive sheet. The upper limit value in the case where the peeling speed is the former (40 m / min or more) is not particularly limited, but usually the case where the peeling speed is the latter (0.25 m / min or less) in many cases is usually 100 m / min or less. Although the lower limit in particular is not restrict | limited, Usually, it is often 0.1 m / min or more.
When the peeling speed is 40 m / min or more, since the adhesive layer surface cannot follow the film to be peeled when peeling the heavy release film or the light release film, the occurrence of zipping is suppressed. On the other hand, when the peeling speed is 0.25 m / min or less, the surface of the adhesive layer can be flexibly changed in shape, thereby suppressing the occurrence of zipping.
Among these, the peeling speed is preferably 80 m / min or more or 0.15 m / min or less in that the occurrence of zipping can be further suppressed.

The said requirement 2 prescribes | regulates that the temperature of an adhesion layer is 35 degreeC or more or 5 degrees C or less when peeling a heavy peeling film or a light peeling film from a double-sided adhesive sheet. The upper limit in the case where the temperature of the pressure-sensitive adhesive layer is the former (35 ° C. or higher) is not particularly limited, but is usually 80 ° C. or lower, and in the case where the temperature of the pressure-sensitive adhesive layer is the latter (5 ° C. or lower). The lower limit is not particularly limited, but is usually -80 ° C or more in many cases.
When the temperature of the pressure-sensitive adhesive layer is 35 ° C. or higher, the surface of the pressure-sensitive adhesive layer can be flexibly changed when the heavy release film or the light release film is peeled off, thereby suppressing the repelling of zipping. On the other hand, when the temperature of the pressure-sensitive adhesive layer is 5 ° C. or less, the occurrence of zipping is suppressed because the surface of the pressure-sensitive adhesive layer cannot be followed when the heavy release film or the light release film is peeled off. Among these, the temperature of the adhesive layer is preferably 40 ° C. or higher or −5 ° C. or lower in that the occurrence of zipping can be further suppressed.

As a method for peeling the heavy release film or the light release film from the double-sided pressure-sensitive adhesive sheet, a known method can be adopted. For example, a known release device is used to hold one end of the heavy release film (or the light release film). The method of peeling so that it may keep away from an adhesion layer is mentioned.
The method for adjusting the temperature of the adhesive layer is not particularly limited, and examples thereof include a method of allowing the adhesive sheet to stand for a certain period of time in a heating device such as an oven or a cooling device such as a refrigerator to reach a predetermined temperature. It is done.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

(Production Example 1)
21.8 parts by mass of a polyisoprene polymer maleic anhydride adduct and 2-hydroxyethyl methacrylate ester (trade name UC203, manufactured by Kuraray Co., Ltd., molecular weight 36000), polybutadiene (trade name Polyvest110, manufactured by Evonik Degussa) ) 11.4 parts by mass, 5 parts by mass of dicyclopentenyloxyethyl methacrylate (trade name FA512M, manufactured by Hitachi Chemical Co., Ltd.), 20 parts by mass of 2-ethylhexymethacrylate (manufactured by Wako Pure Chemical Industries, Ltd.), terpene-based hydrogen 38.8 parts by mass of an additive resin (trade name Clearon P-135, manufactured by Yasuhara Chemical Co., Ltd.) was kneaded in a kneading machine in a 130 ° C. constant temperature bath, and then the temperature of the constant temperature bath was adjusted to 80 ° C. Photopolymerization initiator (trade name Lucirin TPO, manufactured by BASF) 0.6 parts by mass, and photopolymerization start It was charged (trade name of Irgacure 184, manufactured by BASF) 2.4 parts by weight were kneaded by a kneader to prepare a pressure-sensitive adhesive 1.
The obtained pressure-sensitive adhesive 1 was applied on the surface-treated surface of a predetermined 75 μm-thick release film (heavy release film) shown in Table 2 so that the thickness of the formed pressure-sensitive adhesive layer was 100 μm. A surface-treated surface of a predetermined desired 50 μm thick release film (light release film) shown in Table 2 was bonded onto the film. Using a metal halide UV lamp (manufactured by Fusion UV Systems), the coating film sandwiched between the release films is irradiated with UV light so that the irradiation energy is 1 J / cm ² , and double-sided adhesive sheets (double-sided adhesive sheets 1, 3) 5, 7, and 11) were obtained.

(Production Example 2)
21.8 parts by mass of an esterified product of maleic anhydride adduct of polyisoprene polymer and 2-hydroxyethyl methacrylate (trade name UC102, manufactured by Kuraray Co., Ltd., molecular weight 19000), polybutadiene (trade name: Polybest 110, manufactured by Evonik Degussa) 8.8 parts by mass, 20 parts by mass of isobornyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), 5 parts by mass of 2-ethylhexyl acrylate (manufactured by Wako Pure Chemical Industries, Ltd.), 2.6 masses of dodecanethiol (manufactured by Tokyo Chemical Industry Co., Ltd.) Part, 38.8 parts by mass of a terpene-based hydrogenated resin (trade name Clearon P-135, manufactured by Yasuhara Chemical Co., Ltd.) in a thermostatic bath at 130 ° C., and then the temperature of the thermostatic bath is set to 80. The temperature was adjusted to 0 ° C., 3 parts by mass of a photopolymerization initiator (trade name Lucirin TPO, manufactured by BASF) was added, kneaded in a kneader, The agent 2 was prepared.
The obtained pressure-sensitive adhesive 2 was applied on the surface-treated surface of a 75 μm-thick release film (heavy release film) shown in Table 2 so that the thickness of the formed pressure-sensitive adhesive layer was 100 μm, and the obtained coating film The surface-treated surface of a 50 μm thick release film (light release film) shown in Table 2 was bonded to the surface. Using a metal halide UV lamp (manufactured by Fusion UV Systems), the coating film sandwiched between the release films is irradiated with UV light so that the irradiation energy is 1 J / cm ² , and double-sided adhesive sheets (double-sided adhesive sheets 2, 4) 6, 8, 9, 10, and 12).

(Production Example 3)
As a crosslinking agent, 100 parts by mass of an acrylic adhesive main agent having 4.5% by mass of 4-hydroxybutyl acrylate unit (4-HBA), 60% by mass of butyl acrylate unit and 35.5% by mass of methyl acrylate unit. 0.3 parts by mass of tolylene diisocyanate compound (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.), pentaerythritol-tetrakis (3- (3,5-di-t-) as a hindered phenol-based antioxidant (Butyl-4-hydroxyphenyl) propionate) (trade name: IRGANOX1010, BASF Japan Ltd.) 0.7 parts by weight, tris (2,4-di-t-butylphenyl) phosphite (product) Name IRGAFOS168, BASF Japan Co., Ltd.) 0.5 parts by mass, Was obtained (carboxyl group content of 0 mass%).
The obtained pressure-sensitive adhesive 3 was coated on the 75 μm-thick release film (heavy release film) shown in Table 2 so that the thickness of the formed pressure-sensitive adhesive layer was 100 μm, and heated at 100 ° C. for 3 minutes. An adhesive layer was formed. A 50 μm thick release film (heavy release film) shown in Table 2 was bonded to this adhesive layer to obtain a double-sided adhesive sheet 13.

(Production Example 4)
16 parts by mass of isoprene polymer (trade name LIR-30, manufactured by Kuraray Co., Ltd.), 16.5 parts by mass of polybutadiene (trade name Polybest 110, manufactured by Evonik Degussa), 15.5 parts by mass of isobornyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) , 7.5 parts by mass of 2-ethylhexyl acrylate (manufactured by Wako Pure Chemical Industries, Ltd.), 2 parts by mass of 3,4-epoxycyclohexylmethyl methacrylate (trade name Cyclomer M-100, manufactured by Daicel), terpene-based hydrogenation 39 parts by mass of resin (trade name: Clearon P-135, manufactured by Yasuhara Chemical Co., Ltd.) and 0.5 parts by mass of phosphorus-based processing heat stabilizer (trade name: Irgafos 168, manufactured by BASF) are mixed in a kneading machine in a thermostatic bath at 130 ° C. Then, the temperature of the thermostatic bath is adjusted to 80 ° C., and the photopolymerization initiator 1 (trade name Lucirin TPO, BASF 1.5 parts by mass, 1 part by mass of photopolymerization initiator 2 (trade name Irgacure 819), and 0.5 part by mass of photopolymerization initiator 3 (trade name Irgacure 184) were charged in a kneader. The pressure-sensitive adhesive 4 was prepared by kneading.
The obtained pressure-sensitive adhesive 4 was applied on the surface-treated surface of a 75 μm-thick release film (heavy release film) shown in Table 2 so that the thickness of the formed pressure-sensitive adhesive layer was 200 μm. The surface-treated surface of a 50 μm thick release film (light release film) shown in Table 2 was bonded to the surface. Using a metal halide UV lamp (manufactured by Fusion UV Systems), the coating film sandwiched between the release films is irradiated with UV light so that the irradiation energy is 2.5 J / cm ² , and a double-sided adhesive sheet (double-sided adhesive sheet 14). )

(Calculation method of I / O ratio)
The definition of the I value and O value in the organic conceptual diagram is described in detail in the above-mentioned “new edition organic conceptual diagram basics and application” (hereinafter also referred to as a series), and the present invention is also a method described in the series according to the description. According to the calculation, the I / O ratio of the adhesive was calculated.
More specifically, first, using a known method (for example, ¹ HNMR measurement), the mol% of each repeating unit contained in the adhesives 1 to 4 produced in each production example is calculated.
The I value and the O value include each atom (for example, carbon atom, halogen or phosphorus atom) included in each repeating unit or each group (for example, unsaturated bond group, aromatic ring group, hetero atom) in the above series. The linking group, the cyano group, the nitro group, and the like) and the sum of the products of the respective atoms and the ratio of each group. Therefore, from the ratio of each group contained in each of the above repeating units and the mol% of each repeating unit, the ratio of each group in the total polymer is calculated, and these and the parameter values described in the above series are used. Thus, the I value and the O value can be calculated. The I / O ratio is obtained as a number obtained by dividing the I value by the O value.
The pressure-sensitive adhesive 1 had an I / O ratio of 0.162, the pressure-sensitive adhesive 2 had an I / O ratio of 0.171, and the pressure-sensitive adhesive 3 had an I / O ratio of 0.782.

<Various evaluations>
The following evaluation was performed using the double-sided PSA sheets 1 to 14 obtained above.

(Peeling force evaluation)
Using AUTOGRAPH AGS-J (manufactured by Shimadzu Corporation), peeling force was evaluated according to the following method.
First, each double-sided PSA sheet was cut out to a width of 25 mm and a length of 150 mm.
Next, leaving only the light release film, the adhesive layer and heavy release film for 100 mm in the longitudinal direction are removed, and the remaining 50 mm heavy release film is applied to the base material (stainless steel) with a double kilogram heavy roller via a double-sided tape. Is applied to the light release film in a 180 degree direction at a speed of 300 mm / sec to obtain a peel force (light peel force) (N / mm) for the adhesive layer of the light peel film. It was.
Also, leaving only the heavy release film, the adhesive layer and the light release film for 100 mm in the longitudinal direction are removed, the remaining light release film is peeled off, and the surface of the exposed adhesive layer is 2 kg on the substrate (stainless steel). The roller is reciprocated once and attached, and a tensile test is performed by pulling the heavy release film at a direction of 180 degrees and a speed of 300 mm / sec, and the peeling force (heavy peeling force) (N / mm) to the adhesive layer of the heavy peeling film is measured. Asked.
When the heavy peel force is 0.08 N / mm or less and the light peel force is 0.03 N / mm or less, the peelability is good (“A”) and the heavy peel force is 0.08 N / mm. When it was over or the light peel force was over 0.03 N / mm, the peelability was regarded as poor (“B”).

(Crying separation evaluation)
Each double-sided pressure-sensitive adhesive sheet was punched into a size of φ16 mm to prepare three samples. About each sample, the light peeling film was peeled off with the tape, and the state of the adhesion layer at the time of peeling was evaluated according to the following references | standards. If the evaluation result of three samples is “A”, if the evaluation result is “A”, the crying evaluation of the double-sided adhesive sheet is “A”. did.
“A”: No crying farewell “B”: Crying farewell

(Adhesion evaluation)
Cut each double-sided PSA sheet to 25mm x 50mm, peel off the light release film and paste the exposed adhesive layer to glass (Corning Eagle XG 75 x 50 x 1100mm), then peel off the heavy release film The surface of the exposed adhesive layer was bonded to a polyimide sheet (Kapton 100H 30 mm × 140 mm) by reciprocating a 2 kg heavy roller one by one in the width direction, and then depressurized at 40 ° C. and 5 atm for 20 minutes. A foam treatment was applied. After being left for one day, one end of the polyimide sheet was held and a tensile test was performed at a direction of 180 degrees and a speed of 300 mm / sec.
The case where the obtained peeling force (N / mm) was larger than the reference value or within 5% of the reference value was designated as “A”, and the case where it exceeded 5% was designated as “B”. As the evaluation method, first, NZ208 (manufactured by Toyobo Co., Ltd.) is used as the heavy release film, and NZ211 (manufactured by Toyobo Co., Ltd.) is used as the light release film, and the same as described in (Production Example 1) to (Production Example 4). According to the procedure, reference samples 1 to 4 using adhesives 1 to 4 (for example, a reference sample manufactured using adhesive 1 corresponds to “reference sample 1”) were prepared. Next, the peeling force was measured by the above method using the prepared reference sample, and the peeling force (reference value) of each reference sample was obtained. Then, in accordance with the type of pressure-sensitive adhesive in the pressure-sensitive adhesive layer in each double-sided pressure-sensitive adhesive sheet used in Examples and Comparative Examples, the peel force obtained from each double-sided pressure-sensitive adhesive sheet used in Examples and Comparative Examples and The difference (%) from the peeling force obtained from the reference sample [{(peeling force at the reference sample−peeling force at each double-sided pressure-sensitive adhesive sheet) / peeling force at the reference sample} × 100] was determined. More specifically, since the pressure-sensitive adhesive 1 is used in the pressure-sensitive adhesive sheet 1, a comparison with the peeling force of the reference sample 1 was performed.

(Evaluation of peeling over time)
Each of the pressure-sensitive adhesives 1 to 4 is applied on a 75 μm-thick release film (heavy release film) shown in Table 2 in a roll shape having a width of 1100 mm so as to have a thickness of 100 μm to form a coating film. The same roll-shaped 50 μm-thick release film (light release film) shown in Table 2 was laminated and cured under the same conditions as the production conditions for each double-sided PSA sheet. It was wound up on a plastic core. The wound double-sided pressure-sensitive adhesive sheet was stored in a suspended state for 6 months at room temperature, and the surface condition after storage was evaluated. When peeling occurred between the pressure-sensitive adhesive layer and the release film, B was indicated, and when peeling did not occur, A was assumed.
In addition, the combination of the adhesive, the heavy release film, and the light release film in the samples of each Example and Comparative Example used in the above-described peel evaluation was in accordance with the combinations shown in Table 2.

(Temperature dependency evaluation)
One release film on the surface of each double-sided PSA sheet is peeled off, and the exposed adhesive layer (thickness: 100 μm or 200 μm) is bonded onto an Al (aluminum) electrode 20 mm long × 20 mm wide and 0.5 mm thick. After that, the other release film is peeled off, the Al electrode is bonded to the exposed adhesive layer, and then subjected to pressure defoaming treatment at 40 ° C., 5 atm for 60 minutes to evaluate temperature dependence. A test sample was prepared.
The thickness of the pressure-sensitive adhesive layer in each sample was measured at five locations on the sample for temperature dependence evaluation test with a micrometer, and the thickness of the two Al electrodes was subtracted from the average value. The thickness was calculated.

Using the temperature dependency evaluation test sample prepared above, impedance measurement was performed at 1 MHz with an impedance analyzer (Agilent 4294A), and the relative dielectric constant of the adhesive layer was measured.
Specifically, the temperature dependence evaluation test sample was gradually raised from −40 ° C. to 80 ° C. in steps of 20 ° C., and impedance measurement at 1 MHz using an impedance analyzer (Agilent 4294A) at each temperature. The capacitance C was determined. At each temperature, the sample was allowed to stand for 5 minutes until the sample temperature became constant.
Then, using the obtained capacitance C, the relative dielectric constant at each temperature was calculated from the following formula (X).
Formula (X): relative dielectric constant = (capacitance C × thickness T) / (area S × vacuum dielectric constant ε ₀ )
The thickness T is the thickness of the adhesive layer, the area S is the aluminum electrode area (vertical 20 mm × horizontal 20 mm), and the vacuum permittivity ε ₀ is a physical constant (8.854 × 10 ⁻¹² F / m). To do.
The minimum value and the maximum value are selected from the calculated relative dielectric constants, and the temperature dependence (%) (Δε%) is obtained from the formula [{(maximum value−minimum value) / minimum value} × 100]. It was.
The temperature was adjusted using a liquid nitrogen cooling stage when the temperature was low, and using a hot plate when the temperature was high.

In Table 2, the “type” column in the “heavy release film” column and the “type” column in the “light release film” column indicate the product name of each company, and the types of release films used are as follows: It is as follows.
"T-204": Coat film, "CA0" manufactured by Lintec Corporation: Silicone release film, "WZ" manufactured by Fujiko Co., Ltd., "CA1" manufactured by Toray Industries, Inc .: Silicone release film, "NZ208" manufactured by Fujiko Co., Ltd .: ester film, “1130” manufactured by Toyobo Co., Ltd. “1130H” manufactured by Lintec Co., Ltd. “C1” manufactured by Lintec Co., Ltd .: Silicone release film, “MFA” manufactured by Fujiko Co., Ltd., “NZ211” manufactured by Toray Industries, Ltd .: ester film, “BKE” manufactured by Toyobo Co., Ltd .: therapy, “Q2” manufactured by Toray Industries, Inc .: PET separator, manufactured by Nipper

In Table 2, the value of the dispersion component of the surface free energy was measured by the method described above.
In Table 2, “-” means not implemented.

As shown in Table 2 above, it was confirmed that the double-sided PSA sheet of the present invention can achieve the desired effect.
On the other hand, Comparative Examples 1, 2 and 4 in which the surface free energy dispersion component of the release film is not within the predetermined range, the value of the surface free energy dispersion component of the heavy release film and the value of the surface free energy dispersion component of the light release film The desired effect was not obtained in Comparative Example 3 in which the difference between the two values was not in the predetermined range and in Comparative Example 5 in which the temperature dependence was not in the predetermined range.

  The following zipping evaluation was implemented using the double-sided adhesive sheet 4 and the double-sided adhesive sheet 14 produced above.

(Zipping evaluation)
A double-sided pressure-sensitive adhesive sheet (double-sided pressure-sensitive adhesive sheet 4 or double-sided pressure-sensitive adhesive sheet 14) is cut out to a width of 25 mm and a length of 150 mm, the pressure-sensitive adhesive layer and light release film for 100 mm in the longitudinal direction are removed, and the remaining light release film is peeled off. A measurement sample was prepared by attaching the film to a film, and a peel test of the heavy release film was performed at a predetermined peel rate shown in Table 3 in a room temperature environment.
Also, as shown in Table 4, when changing the temperature of the adhesive layer, when adjusting the temperature of the adhesive layer to a higher temperature side than room temperature, the measurement sample is left on the hot plate, When adjusting the temperature of the adhesive layer to the low temperature side, leave the measurement sample in the refrigerator or freezer, and after a sufficient time has passed for the temperature of the adhesive layer to reach the predetermined temperature, Alternatively, a measurement sample was taken out from the freezer and immediately placed in a peel tester for testing.
For the peel test, an autograph apparatus (manufactured by Shimadzu Corporation: AGS-J) and a high-speed peel test apparatus (manufactured by Imada Corporation) were used. When noise occurs during peeling, periodic irregularities occur in the adhesive layer, or when periodic vibration is observed in the data on the relationship between the obtained peeling force and tension stroke, zipping occurs (C) When it was not seen, it was judged that there was no zipping (A), and when it was seen slightly, it was judged that there was a slight zipping (B).
In addition, it implemented with the autograph apparatus until the peeling speed was 0.5 m / min, and when the peeling speed exceeded 0.5 m / min, the high-speed peeling test apparatus was used.

As shown in Table 3 above, as can be seen from Examples 10 to 11, Examples 14 to 17, and Examples 20 to 21, when the peeling rate is 40 m / min or more or 0.25 m / min or less, the occurrence of zipping occurs. It was confirmed that it was suppressed.
Further, as shown in Table 4 above, as can be seen from Examples 30 to 31, Examples 34 to 37, and Examples 40 to 41, when the temperature of the adhesive layer is 35 ° C or higher or 5 ° C or lower, the occurrence of zipping occurs. It was confirmed that it was suppressed.

10 Double-sided adhesive sheet 12 Heavy release film 14, 18 Adhesive layer 16 Light release film 200 Aluminum electrode

Claims (7)

A double-sided pressure-sensitive adhesive sheet having a heavy release film, an adhesive layer, and a light release film in this order,
The temperature dependence of the dielectric constant of the adhesive layer obtained from the following temperature dependence evaluation test is 20% or less,
The value of the dispersion component of the surface free energy on the adhesive layer side surface of the heavy release film and the light release film is 11.0 to 13.0 mN / mm,
Wherein the value of the dispersion component of the surface free energy of the peelable film state, and are difference 0.2 mN / mm or more and the value of the dispersion component of the surface free energy of the peelable film,
The pressure-sensitive adhesive layer is a layer obtained by curing a curable pressure-sensitive adhesive composition containing a (meth) acrylate monomer, a polymerization initiator, a tackifier, and a rubber component,
The rubber component contains a rubber component having a polymerizable group;
The content of the tackifier is 80 to 320 parts by mass with respect to 100 parts by mass of the (meth) acrylate monomer, and the content of the rubber component is 70 with respect to 100 parts by mass of the (meth) acrylate monomer. The double-sided pressure-sensitive adhesive sheet , which is ˜320 parts by mass .
Temperature dependency evaluation test: An adhesive layer is sandwiched between aluminum electrodes, heated from −40 ° C. to 80 ° C. every 20 ° C., and the relative dielectric constant of the adhesive layer is calculated by impedance measurement at 1 MHz at each temperature. The minimum value and the maximum value are selected from the calculated relative dielectric constants at the respective temperatures, and the value (%) obtained from the formula [(maximum value−minimum value) / minimum value × 100] is expressed as a temperature dependency. And The double-sided pressure-sensitive adhesive sheet according to claim 1 , wherein the curable pressure-sensitive adhesive composition further contains a chain transfer agent. The double-sided pressure-sensitive adhesive sheet according to claim 1 or 2 , wherein the temperature dependency is 10% or less. It is the peeling method which peels the said heavy release film or the said light release film from the double-sided adhesive sheet of any one of Claims 1-3 ,
A peeling method in which a peeling speed is 40 m / min or more or 0.25 m / min or less when peeling the heavy release film or the light release film. The peeling method according to claim 4 , wherein the peeling speed is 80 m / min or more, or the peeling speed is 0.15 m / min or less. It is the peeling method which peels the said heavy release film or the said light release film from the double-sided adhesive sheet of any one of Claims 1-3 ,
A peeling method in which the temperature of the adhesive layer is 35 ° C. or higher or 5 ° C. or lower when peeling the heavy release film or the light release film. The peeling method according to claim 6 , wherein the temperature is 40 ° C. or higher, or the temperature is −5 ° C. or lower.