WO2019031474A1

WO2019031474A1 - Silicone adhesive sheet or silicone adhesive layer

Info

Publication number: WO2019031474A1
Application number: PCT/JP2018/029522
Authority: WO
Inventors: 泰輔岡本; 美徳塚本
Original assignee: 岩谷産業株式会社; 株式会社テクノフローワン
Priority date: 2017-08-08
Filing date: 2018-08-07
Publication date: 2019-02-14
Also published as: JP2019031610A

Abstract

The present invention provides a silicone adhesive sheet or silicone adhesive layer provided with sufficient bending resistance in a low temperature environment, in particular with sufficient bending resistance at low temperatures to high temperatures, specifically from -20°C to 20°C. The present invention specifically provides a silicone adhesive sheet or silicone adhesive layer provided with at least one requirement from among requirements A) to E), including the following requirements A) to C): A) the storage modulus at -20°C is no higher than 1.0×107 Pa; B) the storage modulus at 20°C is no higher than 1.0×106 Pa; and C) the strain at yield in stress-strain measurement at 20°C is more than 150%.

Description

Silicone adhesive sheet or silicone adhesive layer

The present invention relates to a silicone-based pressure-sensitive adhesive sheet and / or a silicone-based pressure-sensitive adhesive layer. In particular, the present invention relates to a silicone-based pressure-sensitive adhesive sheet and / or a silicone-based pressure-sensitive adhesive layer used for display panels of products such as smartphones, tablet terminals, laptop computers, and more particularly, foldable display panels.

Research and development of bendable displays is in progress. For example, Patent Document 1 discloses a flexible electronic device using a flexible display layer, a flexible touch sensing layer, a flexible display cover layer, etc., and discloses an electronic device having resistance to damage in an impact accident such as falling. ing.

On the other hand, a pressure-sensitive adhesive layer for causing a polarizing plate or a retardation plate used in a liquid crystal display to adhere to a substrate or another optical member, an adhesive film for causing a liquid crystal panel to adhere to a polarizing plate have been used conventionally. There is.
For example, Patent Document 2 discloses a pressure-sensitive adhesive layer that adheres a polarizing plate or a retardation plate used for a liquid crystal display to a substrate or another optical member.
Further, Patent Document 3 discloses a pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet for laminating an optical component such as a display and a surface protective sheet via a pressure-sensitive adhesive.

JP-A-2015-501461 gazette. JP-A-9-243824. JP-A-2015-131945.

However, when the conventional adhesive film is used for a foldable display, there is a problem that the bending resistance is not sufficient, particularly, the problem that the bending resistance in a low temperature environment is not sufficient. There is. Specifically, the adhesion with the liquid crystal panel and / or the polarizing plate, which are objects to be adhered, becomes poor, and when it is bent, a problem such as peeling or cracking being observed in the bent portion occurs.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art described above.
Specifically, it is an object of the present invention to provide a silicone-based pressure-sensitive adhesive sheet having sufficient bending resistance under a low temperature environment, in particular, sufficient bending resistance from a low temperature to a high temperature, specifically from -20 ° C to 20 ° C. Or to provide a silicone-based adhesive layer.
Another object of the present invention is to provide a product comprising the silicone-based pressure-sensitive adhesive sheet and / or the silicone-based pressure-sensitive adhesive layer, specifically a display, more specifically a flexible display.

The present inventors have found the following invention.
<1> A) Storage modulus at -20 ° C. is 1.0 × 10 ⁷ Pa or less, preferably 5.0 × 10 ⁶ to 1.0 × 10 ⁴ Pa, more preferably 1.0 × 10 ⁶ to 5 0. 10 × 10 ⁴ Pa, a silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer.
<2> In the above <1>, B) storage elastic modulus at 20 ° C. is 1.0 × 10 ⁶ Pa or less, preferably 1.0 × 10 ⁶ to 1.0 × 10 ³ Pa, more preferably 5.0 It is preferable that x 10 ⁵ to 1.0 x 10 ⁴ Pa be established.
<3> In the above <1> or <2>, C) the yield point strain in stress-strain measurement at 20 ° C. exceeds 150%, preferably 180% or more, more preferably 230% or more .

<4> The test according to D) IEC62715-6-1 Ed 1.0 according to any one of the above <1> to <3>, comprising the silicone-based pressure-sensitive adhesive sheet or the silicone-based pressure-sensitive adhesive layer. The test piece which consists of a PET 100 μm / the adhesive sheet or the adhesive layer / PET 100 μm and has a length of 100 mm and a width of 50 mm has both ends defining the length from the initial state of 100 mm. In a test in which the test piece is changed to a folded state by the weight of the test piece so that the distance between the test pieces is 5 mm, the test at a temperature of -20 ° C is repeated more than 100,000 times, preferably at least 200,000 times, more preferably 60 It should be 10,000 times or more.

<5> In any of the above <1> to <4>, in the same test as E) above D), the test at a temperature of 20 ° C. is repeated 200,000 times or more, preferably 400,000 or more, more preferably Is more than 600,000 times, more preferably more than 800,000 times, and most preferably more than 1,000,000 times.

<6> B) Storage elastic modulus at 20 ° C. is 1.0 × 10 ⁶ Pa or less, preferably 1.0 × 10 ⁶ to 1.0 × 10 ³ Pa, more preferably 5.0 × 10 ⁵ to 1. A silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer which has 0 × 10 ⁴ Pa.
<7> In the above item <6>, C) the yield point strain in stress-strain measurement at 20 ° C. is more than 150%, preferably 180% or more, more preferably 230% or more.

<8> In the above <6> or <7>, in the same test as D) above D), the test at a temperature of −20 ° C. has a repetition of more than 100,000 times, preferably at least 200,000 times, more preferably 60 It should be 10,000 times or more.

<9> In any of the above <6> to <8>, in the same test as E) above D), the test repeated at a temperature of 20 ° C. exceeds 200,000 times, preferably at least 400,000 times, more preferably Is more than 600,000 times, more preferably more than 800,000 times, and most preferably more than 1,000,000 times.

<10> C) A silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer in which the yield point strain in stress-strain measurement at 20 ° C. exceeds 150%.
<11> In the above <10>, in the same test as D) and D), repetition of the test at a temperature of −20 ° C. exceeds 100,000 times, preferably at least 200,000 times, more preferably at least 600,000 times Good to have.

<12> In any of the above <10> or <11>, in the same test as E) above D), the repetition of the test at a temperature of 20 ° C. exceeds 200,000 times, preferably at least 400,000 times, more preferably Is more than 600,000 times, more preferably more than 800,000 times, and most preferably more than 1,000,000 times.

<13> D) A silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer having a bending resistance of which repetition of the test at a temperature of −20 ° C. exceeds 100,000 times in the same test as the above D).

<14> In the above <13>, in the same test as E) above D), whether the repetition of the test at a temperature of 20 ° C. exceeds 200,000 times, preferably not less than 400,000 times, more preferably more than 600,000 times More preferably, it is 800,000 times or more, and most preferably 1,000,000 times or more.

<15> E) In the same test as above D), the test is repeated at a temperature of 20 ° C. for at least 200,000 times, preferably at least 400,000 times, more preferably at least 600,000 times, further preferably 800,000. A silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer having a bending resistance which is more than once, most preferably more than 1,000,000 times.

<16> A product comprising the silicone-based pressure-sensitive adhesive sheet and / or the silicone-based pressure-sensitive adhesive layer according to any one of the above <1> to <15>.
<17> A display comprising the silicone-based pressure-sensitive adhesive sheet and / or the silicone-based pressure-sensitive adhesive layer according to any one of the above <1> to <15>.
<18> A flexible display comprising the silicone-based pressure-sensitive adhesive sheet and / or the silicone-based pressure-sensitive adhesive layer according to any one of the above <1> to <15>.

The present invention can solve the problems of the prior art described above.
Specifically, according to the present invention, a silicone-based pressure-sensitive adhesive sheet or silicone having sufficient bending resistance in a low temperature environment, in particular, sufficient bending resistance at low to high temperatures, specifically at -20 ° C to 20 ° C. A pressure-sensitive adhesive layer can be provided.
Further, according to the present invention, it is possible to provide a product comprising the silicone-based pressure-sensitive adhesive sheet and / or the silicone-based pressure-sensitive adhesive layer, specifically a display, more specifically a flexible display.

It is a schematic diagram of the bending resistance test in the requirements D) and E) of this application. It is a graph which shows the stress-strain curve (20 degreeC) of Example 1, Example 3, and the comparative example 3, and the yield point distortion in this curve. It is the graph which made the yield point distortion of Example 1, Example 3, and Comparative Example 3 the horizontal axis, and makes a bending test result (20 ° C) the vertical axis.

Hereinafter, the invention described in the present application will be described in detail.
The present application provides a silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer comprising at least one of the requirements A) to E).
The present application also provides a product comprising the silicone-based pressure-sensitive adhesive sheet and / or the silicone-based pressure-sensitive adhesive layer, specifically a display, more specifically a flexible display.
Hereinafter, the silicone-based adhesive sheet or the silicone-based adhesive layer provided by the present application will be described.

The present application provides a silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer comprising at least one of the following requirements A) to E).
A) The storage elastic modulus at −20 ° C. is 1.0 × 10 ⁷ Pa or less, preferably 5.0 × 10 ⁶ to 1.0 × 10 ⁴ Pa, more preferably 1.0 × 10 ⁶ to 5.0 × 10 ⁴ Pa;
B) Storage elastic modulus at 20 ° C. is 1.0 × 10 ⁶ Pa or less, preferably 1.0 × 10 ⁶ to 1.0 × 10 ³ Pa, more preferably 5.0 × 10 ⁵ to 1.0 × 10 ⁵ ⁴ Pa;
C) Yield point strain in stress-strain measurement at 20 ° C. exceeds 150%. Preferably, the yield point strain is 180% or more, more preferably 230% or more;
D) In the bending resistance test (the details of the bending resistance test will be described later) in accordance with IEC 62715-6-1 Ed 1.0, the test at a temperature of -20 ° C is repeated 100,000 times, preferably 200,000 times, more Preferably with a bending resistance of more than 600,000 times;
E) In the same bending resistance test as in D) above, the test conforms to IEC62715-6-1 Ed1.0, and the test is repeated at a temperature of 20 ° C. at more than 200,000 times, preferably at least 400,000 times More preferably, it has bending resistance which is more than 600,000 times, more preferably more than 800,000 times, and most preferably more than 1,000,000 times.
Here, the bending resistance test in accordance with IEC 62715-6-1 Ed 1.0 is performed as follows. The test piece used in the test is a test piece having a silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer, and the composition thereof is composed of three layers of PET 100 μm / the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layer / PET 100 μm, and has a length of 100 mm and a width Is 50 mm. The thickness of the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layer depends on the thickness of the pressure-sensitive adhesive sheet to be tested or the pressure-sensitive adhesive layer. The obtained test piece is changed from an initial state of 100 mm in length to a bent state in which the test piece is bent by its own weight so that both ends defining the length have a distance of 5 mm. Repeat the initial state and the bending state, and measure the number of occurrences of breakage.

The silicone-based pressure-sensitive adhesive sheet or silicone-based pressure-sensitive adhesive layer of the present invention has at least one of the requirements of the above A) to E).
At least two of the requirements A) to E) may be provided. For example, a combination of A) and B), a combination of A) and C), a combination of A) and D), a combination of A) and E), a combination of B) and C), B) A combination of D), a combination of B) and E), a combination of C) and D), a combination of C) and E), a combination of D) and E), Is good.

In addition, at least three of the requirements A) to E) may be provided. For example, a combination of A), B) and C), a combination of A) and B) and D), a combination of A) and B) and E), a combination of A) and C) and D), Combinations of A), C) and E), A) and D) and E), B) and C) and D), B) and C) and E), B) And any combination of C), D), and E).

Furthermore, it is preferable to provide four of the requirements A) to E). For example, a combination of A), B), C) and D), a combination of A), B) and C) and E), a combination of A) and B) and D) and E), A) and A combination of C), D) and E), or a combination of B), C) and D), and E) may be provided.
In addition, all the requirements of the above A) to E) should be provided.

In the present application, “adhesion” of a silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer means that the adhesiveness measured at 23 ° C. according to the adhesiveness test of JIS Z-0237 is 5 N / (25 mm) or more. The adhesion value is preferably 8 to 30 N / (25 mm), more preferably 8 to 25 N / (25 mm).
The tackiness can be measured at 23 ° C. by the tackiness test of JIS Z-0237 as described above, and is not limited to the device used for the measurement.

Furthermore, in the present application, the term "sheet" or "layer" of a silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer is intended to be in the form of a "sheet" regardless of whether or not it is self-supporting. It is In addition, when it forms on a base material etc., it is generally called a "layer" and it is the intention which also prescribes | regulates a "sheet" or "layer" in this application in parallel including this "layer". is there.

Furthermore, in the present application, “silicone-based” of the silicone-based pressure-sensitive adhesive sheet or the silicone-based pressure-sensitive adhesive layer uses silicone as an essential component, and may contain other components.

Hereinafter, the requirements of A) to E) will be described in detail.
<Requirement A)> and <Requirement B)>
The requirements of A) and B) both specify storage modulus.
The requirement of A) is defined for storage elastic modulus at −20 ° C., and the value is 1.0 × 10 ⁷ Pa or less, preferably 5.0 × 10 ⁶ to 1.0 × 10 ⁴ Pa, more preferably 1 It is defined that .0 × 10 ⁶ to 5.0 × 10 ⁴ Pa.
The requirement of B) defines the storage elastic modulus at 20 ° C., and the value is 1.0 × 10 ⁶ Pa or less, preferably 1.0 × 10 ⁶ to 1.0 × 10 ³ Pa, more preferably 5. It is defined that it is 0 × 10 ⁵ to 1.0 × 10 ⁴ Pa.
The storage elastic modulus can be measured by a conventionally known method, and is not particularly limited to the method used or the device used. For example, the storage elastic modulus can be measured by a shear method, such as a method according to JIS K 7244, and can be measured by a commercially available rheometer.

<Requirement C)>
The requirements in C) specify the strain at yield point in stress-strain measurement at 20 ° C., and the value should be more than 150%, preferably 180% or more, more preferably 230% or more , To prescribe.
Here, the stress-strain measurement can be performed by a shear method, for example, a method according to JIS K 6850, and can be measured by a commercially available device.

<Requirement D)> and <Requirement E)>
The requirements of D) and E) both specify the bending resistance, in particular the resistance to bending test according to IEC 62715-6-1 Ed 1.0.
The bending resistance test specified in the requirements D) and E) of the present application will be described in detail.
The bending resistance test prescribed in the requirements D) and E) of the present application is a test in accordance with IEC 62715-6-1 Ed 1.0.
The test piece used in the test is a test piece having a silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer, and the composition thereof is composed of three layers of PET 100 μm / the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layer / PET 100 μm, and has a length of 100 mm and a width Is 50 mm. The thickness of the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layer depends on the thickness of the pressure-sensitive adhesive sheet to be tested or the pressure-sensitive adhesive layer.
The obtained test piece is changed from an initial state of 100 mm in length to a bent state in which the test piece is bent by its own weight so that both ends defining the length have a distance of 5 mm. The test is repeated, and if a crack such as a crack occurs in the test piece, the number of repetitions up to the previous time is measured as the number of times having resistance.

FIG. 1 is a schematic view of a bending resistance test in the requirements D) and E). Hereinafter, the bending resistance test in the requirements D) and E) will be described with reference to FIG.
The test piece is fixed at one end in the longitudinal direction at the fixed end 1 and at the other end in the longitudinal direction at the free end 2. When the free end 2 is at the position in the state A, the state is close to the initial state (length 100 mm). State D is a bending state in which both ends defining the length of the test piece have a distance of 5 mm. While moving the free end 2 in the X direction so that the initial state → the state A → the state B → the state C → the state D, the test piece is bent by its own weight. Thereafter, the free end 2 is moved in the Y direction from the state D, and the state C → the state B → the state A → the initial state.
Initial state → state A → state B → state C → state D → state C → state B → state A → initial state is repeated once, and if cracks or cracks occur in the test piece, the previous time The number of repetitions up to is measured as the number of times having resistance.

The environmental temperature of the test was -20.degree. C. in requirement D) and 20.degree. C. in requirement E).
In requirement D), the temperature should be -20 ° C, and the repetition should be 100,000 times, preferably 200,000 times, more preferably 600,000 times, and the presence or absence of bending resistance is determined depending on whether it is achieved or not Do.
In the requirement E), at a temperature of 20 ° C., repetition is more than 200,000 times, preferably more than 400,000 times, more preferably more than 600,000 times, still more preferably 800,000 times or more, most preferably 1,000,000 times The above is good, and the presence or absence of bending resistance is determined depending on whether or not to achieve it.

As described above, by providing at least one, preferably at least two, more preferably at least three, still more preferably at least four, most preferably five of the above requirements A) to E). The object of the invention is to achieve a silicone-based PSA sheet or a silicone-based PSA layer which has sufficient bending resistance under low temperature environment, in particular sufficient bending resistance from low temperature to high temperature, specifically from -20 ° C to 20 ° C. can do.

The thickness is not limited as long as the silicone-based pressure-sensitive adhesive sheet or the silicone-based pressure-sensitive adhesive layer of the present application satisfies the requirements A) to E) as described above. The thickness of the silicone-based pressure-sensitive adhesive sheet or silicone-based pressure-sensitive adhesive layer in the present invention depends on the silicone-based material to be used, and is 200 to 10 μm, preferably 100 to 10 μm, more preferably 50 to 10 μm.
The silicone-based pressure-sensitive adhesive sheet or silicone-based pressure-sensitive adhesive layer of the present application should have desired optical properties.
Examples of optical properties include, but are not limited to, transmittance, haze, refractive index, color difference, and the like.
For example, a sample having a desired thickness and having a silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer of the present invention sandwiched by glass slides of 0.3 mm thickness is a haze according to a measuring method according to JIS-K-7130. To have optical properties of haze: 1.0% or less, transmittance (wavelength: visible light region): 92% or more, color difference (b * value): 0.5 or less by measuring transmittance and color difference It is preferable that it is a silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer.

Although the manufacturing method of the above-mentioned silicone type adhesive sheet or a silicone type adhesive layer describes the one aspect in the below-mentioned Example, if a silicone type adhesive sheet or a silicone type adhesive layer which fulfills the above-mentioned requirements can be manufactured, It is not limited to the manufacturing method described in the below-mentioned Example.

The present invention further provides a product comprising the above-mentioned silicone-based pressure-sensitive adhesive sheet or silicone-based pressure-sensitive adhesive layer.
The product is not particularly limited as long as it is a product that is required to have desired adhesiveness and is required to have bending resistance.
For example, the product may be a product such as a smartphone, a tablet terminal, a laptop computer, particularly a display of the product, more particularly a flexible display, a foldable display, etc., but not limited thereto.

Hereinafter, the present invention will be described in detail using the following examples, but the present invention is not limited to the following examples.

Example 1
<Preparation of Adhesive Sheet X-1>
The adhesive sheet X-1 was prepared by the following procedure.
75 parts of an addition-curable silicone adhesive (KR3700 manufactured by Shin-Etsu Chemical Co., Ltd.), 25 parts of an addition-curable silicone adhesive (X-40-3365 manufactured by Shin-Etsu Chemical Co., Ltd.), and a platinum catalyst (CAT manufactured by Shin-Etsu Chemical Co., Ltd.) A coating agent A was prepared by adding 0.47 parts of PL-50T and 12.5 parts of toluene and mixing them uniformly.
The obtained coating agent A is applied to a substrate (PET 75-FSC6, manufactured by NIPPA, thickness: 75 μm), dried with hot air at 150 ° C. for 4 minutes, and then the substrate (PET 75-FSC6, manufactured by NIPPA, thickness) The pressure-sensitive adhesive sheet was bonded to a substrate to obtain a pressure-sensitive adhesive sheet X-1.
The thickness of the obtained pressure-sensitive adhesive sheet X-1 was measured to be 50 μm.

<Measurement of storage modulus and yield point strain of adhesive sheet X-1>
The storage elastic modulus and the yield point strain of the pressure-sensitive adhesive sheet X-1 obtained above were measured.
Specifically, the pressure-sensitive adhesive sheet X-1 was peeled off from the base material to prepare a test piece having a diameter of 8 mm and a thickness of 500 to 1000 μm.
The storage elastic modulus of the obtained test piece was measured using a visco-elastic measurement device (DHR-2 manufactured by TA Instruments) at a strain of 1%, a frequency of 1 Hz, and shear at different temperatures (20 ° C, -20 ° C). The elastic modulus was measured.
In addition, the shear stress is observed similarly using a visco-elastic measurement device (DHR-2 manufactured by TA Instruments), and the strain value at which the shear stress is broken is obtained as the stress-strain curve (20 ° C.) of the test piece. The measurement was taken as the yield point by reading, and the yield point strain was obtained.
The obtained results are shown in Table 1.

<Bending test>
The bending test specified in requirement D) and requirement E) was performed.
Specifically, a test piece having a length of 297 mm × a width of 210 mm × a thickness of 50 μm was prepared for the pressure-sensitive adhesive sheet X-1.
Further, two PET substrates having a length of 297 mm × a width of 210 mm and a thickness of 100 μm were prepared.
The test piece of the pressure-sensitive adhesive sheet X-1 was sandwiched by a 100 μm-thick PET substrate so that the PET substrate was placed vertically.
The obtained product was cut into a length of 100 mm and a width of 50 mm, which was used as a test piece for the bending test.
A bending test was conducted at -20 ° C. (requirement D) and 20 ° C. (requirement E), and a point (number of times of bending) at which breakage occurred was observed. In the bending test at −20 ° C. (requirement D), the result of enduring over 100,000 repetitions, that is, the result of over 100,000 times was obtained.
The results of the bending test are shown in Table 1 along with storage modulus and yield point strain.

(Example 2)
A pressure-sensitive adhesive sheet X-2 (thickness 20 μm) was obtained in the same manner as in Example 1, except that the thickness of the pressure-sensitive adhesive sheet was changed to 20 μm using the same coating agent A as in Example 1.
The storage elastic modulus and the yield point strain were measured for the obtained pressure-sensitive adhesive sheet X-2 in the same manner as in Example 1, and the bending test was performed.
The results are shown in Table 1.

(Comparative example 1)
A pressure-sensitive adhesive sheet CX-1 (thickness 100 μm) was obtained by the same method as Example 1, except that the thickness of the pressure-sensitive adhesive sheet was adjusted to 100 μm using the same coating agent A as in Example 1.
The storage elastic modulus and the strain at yield point were measured for the obtained pressure-sensitive adhesive sheet CX-1 in the same manner as in Example 1, and the bending test was performed.
The results are shown in Table 1.

(Example 3)
100 parts of an addition-curable silicone adhesive (SD 4580 PSA manufactured by Toray Dow Corning) and a platinum catalyst (Toray Dow Corning) instead of the addition-curable silicone adhesive and platinum catalyst used in the coating agent A of Example 1 Coating agent B was prepared using 0.54 parts of SRX 212 P CATALYST (manufactured by EIZO Co., Ltd.).
Further, a pressure-sensitive adhesive sheet X-3 (thickness: 50 μm) was obtained by the same method as in Example 1 except that the coating agent B was used instead of the coating agent A in Example 1.
The storage elastic modulus and the strain at yield point were measured for the obtained pressure-sensitive adhesive sheet X-3 in the same manner as in Example 1, and the bending test was performed.
The results are shown in Table 1.

(Comparative example 2)
A pressure-sensitive adhesive sheet CX-2 (thickness 100 μm) was obtained in the same manner as in Example 3, except that the thickness of the pressure-sensitive adhesive sheet was made to be 100 μm using the same coating agent B as in Example 3.
The storage elastic modulus and the strain at the yield point were measured for the obtained pressure-sensitive adhesive sheet CX-2 in the same manner as in Example 1, and the bending test was performed.
The results are shown in Table 1.

(Comparative example 3)
In the coating agent A of Example 1, 100 parts of an addition-curable silicone-based adhesive (KR3700 manufactured by Shin-Etsu Chemical Co., Ltd.) instead of the addition-curable silicone-based adhesive, platinum catalyst and toluene, platinum catalyst (Shin-Etsu Chemical Co., Ltd.) Coating agent C was prepared using 0.20 parts of CAT-PL-50T manufactured by Tokushu K. K., and 46.1 parts of toluene.
Moreover, adhesive sheet CX-3 (50 micrometers in thickness) was obtained by the method similar to Example 1 except having used the coating agent C instead of the coating agent A in Example 1, and being 50 micrometers in thickness. .
The storage elastic modulus and the strain at yield point were measured for the obtained pressure-sensitive adhesive sheet CX-3 in the same manner as in Example 1, and the bending test was performed.
The results are shown in Table 1.

(Comparative example 4)
The storage elastic modulus and the strain at yield point were measured in the same manner as in Example 1 using an acrylic pressure-sensitive adhesive sheet instead of the silicone-based pressure-sensitive adhesive sheet, and a bending test was performed.
Specifically, an acrylic pressure-sensitive adhesive sheet CX-4 (thickness 50 μm) was obtained as follows. That is, a coating agent was prepared by uniformly mixing 100 parts of a two-part acrylic curable adhesive (SK2981 manufactured by Soken Chemical Co., Ltd.) and 0.06 parts of a curing agent (Y-75 manufactured by Soken Chemical Co., Ltd.).
The obtained coating agent is applied to a substrate (US-20, manufactured by Higashiyama Film Co., Ltd., thickness: 50 μm) and dried with hot air at 100 ° C. for 4 minutes, and then the substrate (E7002, manufactured by Toyobo Co., Ltd., thickness: The adhesive surface was attached to 50 μm) to obtain an adhesive sheet CX-4 between the substrates.
The storage elastic modulus and the strain at yield point were measured for the obtained pressure-sensitive adhesive sheet CX-4 in the same manner as in Example 1, and the bending test was performed.
The results are shown in Table 1.

(Comparative example 5)
The storage elastic modulus and the strain at yield point were measured in the same manner as in Example 1 using an acrylic pressure-sensitive adhesive sheet instead of the silicone-based pressure-sensitive adhesive sheet, and a bending test was performed.
Specifically, an acrylic pressure-sensitive adhesive sheet CX-5 (50 μm in thickness) was obtained as follows. That is, a coating agent was prepared by uniformly mixing 100 parts of a two-part acrylic curable adhesive (SK1831 manufactured by Soken Chemical Co., Ltd.) and 0.15 parts of a curing agent (E-AX manufactured by Soken Chemical Co., Ltd.).
The obtained coating agent is applied to a substrate (US-20, manufactured by Higashiyama Film Co., Ltd., thickness: 50 μm) and dried with hot air at 100 ° C. for 4 minutes, and then the substrate (E7002, manufactured by Toyobo Co., Ltd., thickness: The adhesive surface was bonded to 50 μm) to obtain an adhesive sheet CX-5 between the substrates.
The storage elastic modulus and the strain at yield point were measured for the obtained pressure-sensitive adhesive sheet CX-5 in the same manner as in Example 1, and the bending test was performed.
The results are shown in Table 1.

FIG. 2 is a graph showing the stress-strain curve (20 ° C.) and the yield point strain in the curve of Example 1, Example 3 and Comparative Example 3 in which the thickness of the adhesive sheet or adhesive layer is the same. .
FIG. 3 is a graph in which the yield point strain of Example 1, Example 3, and Comparative Example 3 obtained in FIG. 2 is taken along the abscissa and the bending test result (20 ° C.) is taken along the ordinate. is there.

It can be seen from FIGS. 2 and 3 that, particularly, FIG. 3 that the yield point strain and the bending resistance are correlated, and if the yield point strain is high, a high bending resistance is exhibited. In particular, when the strain at yield point exceeds 150%, it is understood that high bending resistance is exhibited.
From Table 1, it can be seen that the pressure-sensitive adhesive sheets or pressure-sensitive adhesive layers of Examples 1 to 3 have high bending resistance in the bending test. In particular, it is understood that the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layer of Examples 1 and 2 has high bending resistance in a bending test.

Claims

A) A silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer having a storage elastic modulus of 1.0 × 10 7 Pa or less at −20 ° C.
B) The silicone-based pressure-sensitive adhesive sheet or silicone-based pressure-sensitive adhesive layer according to claim 1, wherein the storage elastic modulus at 20 ° C. is 1.0 × 10 6 Pa or less.
C) The silicone-based pressure-sensitive adhesive sheet or the silicone-based pressure-sensitive adhesive layer according to claim 1 or 2, wherein the yield point strain in stress-strain measurement at 20 ° C exceeds 150%.
D) A test according to IEC 62715-6-1 Ed 1.0, which is a test piece having the silicone-based pressure-sensitive adhesive sheet or the silicone-based pressure-sensitive adhesive layer, and the structure thereof is PET 100 μm / the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layer / PET 100 μm Bending state that a test piece consisting of 3 layers and having a length of 100 mm and a width of 50 mm is bent from the initial state of 100 mm so that both ends defining the length have a distance of 5 mm The silicone-based pressure-sensitive adhesive sheet or silicone-based pressure-sensitive adhesive layer according to any one of claims 1 to 3, wherein repetition of the test at a temperature of -20 ° C has bending resistance of over 100,000 times in the test to be changed to.
E) A test according to IEC 62715-6-1 Ed 1.0, which is a test piece having the silicone-based pressure-sensitive adhesive sheet or the silicone-based pressure-sensitive adhesive layer, and the structure thereof is PET 100 μm / the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layer / PET 100 μm Bending state that a test piece consisting of 3 layers and having a length of 100 mm and a width of 50 mm is bent from the initial state of 100 mm so that both ends defining the length have a distance of 5 mm The silicone-based pressure-sensitive adhesive sheet or silicone-based pressure-sensitive adhesive layer according to any one of claims 1 to 4, wherein in the test to be changed to, the repetition of the test at a temperature of 20 ° C has bending resistance of over 200,000 times.
B) A silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer having a storage elastic modulus at 20 ° C. of 1.0 × 10 6 Pa or less.
C) The silicone-based pressure-sensitive adhesive sheet or silicone-based pressure-sensitive adhesive layer according to claim 6, wherein a yield point strain in stress-strain measurement at 20 ° C exceeds 150%.
D) A test according to IEC 62715-6-1 Ed 1.0, which is a test piece having the silicone-based pressure-sensitive adhesive sheet or the silicone-based pressure-sensitive adhesive layer, and the structure thereof is PET 100 μm / the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layer / PET 100 μm Bending state that a test piece consisting of 3 layers and having a length of 100 mm and a width of 50 mm is bent from the initial state of 100 mm so that both ends defining the length have a distance of 5 mm The silicone-based pressure-sensitive adhesive sheet or silicone-based pressure-sensitive adhesive layer or silicone-based pressure-sensitive adhesive layer according to claim 6 or 7, wherein repetition of the test at a temperature of -20 ° C has bending resistance of over 100,000 times in the test to be changed to.
E) A test according to IEC 62715-6-1 Ed 1.0, which is a test piece having the silicone-based pressure-sensitive adhesive sheet or the silicone-based pressure-sensitive adhesive layer, and the structure thereof is PET 100 μm / the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layer / PET 100 μm Bending state that a test piece consisting of 3 layers and having a length of 100 mm and a width of 50 mm is bent from the initial state of 100 mm so that both ends defining the length have a distance of 5 mm The silicone-based pressure-sensitive adhesive sheet or silicone-based pressure-sensitive adhesive layer according to any one of claims 6 to 8, wherein in the test to be changed to, the repetition of the test at a temperature of 20 ° C has bending resistance of over 200,000 times.
C) A silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer in which the yield point strain in stress-strain measurement at 20 ° C. exceeds 150%.
D) A test according to IEC 62715-6-1 Ed 1.0, which is a test piece having the silicone-based pressure-sensitive adhesive sheet or the silicone-based pressure-sensitive adhesive layer, and the structure thereof is PET 100 μm / the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layer / PET 100 μm Bending state that a test piece consisting of 3 layers and having a length of 100 mm and a width of 50 mm is bent from the initial state of 100 mm so that both ends defining the length have a distance of 5 mm The silicone-based pressure-sensitive adhesive sheet or silicone-based pressure-sensitive adhesive layer or silicone-based pressure-sensitive adhesive layer according to claim 10, wherein in the test to be changed to, the test at a temperature of -20 ° C has a bending resistance of over 100,000 times.
E) A test according to IEC 62715-6-1 Ed 1.0, which is a test piece having the silicone-based pressure-sensitive adhesive sheet or the silicone-based pressure-sensitive adhesive layer, and the structure thereof is PET 100 μm / the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layer / PET 100 μm Bending state that a test piece consisting of 3 layers and having a length of 100 mm and a width of 50 mm is bent from the initial state of 100 mm so that both ends defining the length have a distance of 5 mm The silicone-based pressure-sensitive adhesive sheet or silicone-based pressure-sensitive adhesive layer or silicone-based pressure-sensitive adhesive layer according to claim 10 or 11, wherein repetition of the test at a temperature of 20 ° C has bending resistance of over 200,000 times in the test to be changed to.
D) A test according to IEC 62715-6-1 Ed 1.0, which is a silicone-based pressure-sensitive adhesive sheet or a test piece having a silicone-based pressure-sensitive adhesive layer, and the structure thereof is PET 100 μm / the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layer / PET 100 μm 3 From the initial state of a 100 mm long and 50 mm wide test piece made of a layer, the test piece is bent by its own weight so that both ends defining the length have a distance of 5 mm. A silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer, in which the test at a temperature of -20 ° C has a bending resistance of over 100,000 times in the test to be changed.
E) A test according to IEC 62715-6-1 Ed 1.0, which is a test piece having the silicone-based pressure-sensitive adhesive sheet or the silicone-based pressure-sensitive adhesive layer, and the structure thereof is PET 100 μm / the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layer / PET 100 μm Bending state that a test piece consisting of 3 layers and having a length of 100 mm and a width of 50 mm is bent from the initial state of 100 mm so that both ends defining the length have a distance of 5 mm The silicone-based pressure-sensitive adhesive sheet or silicone-based pressure-sensitive adhesive layer or silicone-based pressure-sensitive adhesive layer according to claim 13, wherein repetition of the test at a temperature of 20 ° C has bending resistance of over 200,000 times in the test to be changed to.
E) A test according to IEC 62715-6-1 Ed 1.0, which is a silicone-based pressure-sensitive adhesive sheet or a test piece having a silicone-based pressure-sensitive adhesive layer, and the structure thereof is PET 100 μm / the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layer / PET 100 μm 3 From the initial state of a 100 mm long and 50 mm wide test piece made of a layer, the test piece is bent by its own weight so that both ends defining the length have a distance of 5 mm. A silicone-based pressure-sensitive adhesive sheet or a silicone-based pressure-sensitive adhesive layer, in which the test is repeated at a temperature of 20 ° C. with a bending resistance of over 200,000 times in the test to be changed.
An article comprising the silicone-based pressure-sensitive adhesive sheet and / or the silicone-based pressure-sensitive adhesive layer according to any one of claims 1 to 15.
A display comprising the silicone-based pressure-sensitive adhesive sheet and / or the silicone-based pressure-sensitive adhesive layer according to any one of claims 1 to 15.
A flexible display comprising the silicone-based pressure-sensitive adhesive sheet and / or the silicone-based pressure-sensitive adhesive layer according to any one of claims 1 to 15.