Adhesive sheet and decorative adhesive sheet using the same

Abstract

To provide an adhesive sheet for decoration which hardly causes floating between an adherend and the sheet while suppressing foaming from an adhesive layer and an adhesive sheet used for the same.SOLUTION: There is provided an adhesive sheet 12 which is an adhesive sheet used for attaching a decorative sheet to an adherend and is provided with a silicone-based adhesive layer 3. When the storage elastic modulus of the adhesive layer 3 under the conditions of 23°C and a frequency of 1 Hz is expressed as G1' (Pa) and the storage elastic modulus of the adhesive layer 3 under the conditions of 100°C and a frequency of 1 Hz is expressed as G2' (Pa), G2' / G1' is 0.3 or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The technology disclosed in this specification relates to an adhesive sheet used for decorative molding of articles.

Background Art

[0002] Decorative molding is performed for the purpose of decorating automotive interior and exterior parts, building supplies, daily necessities, and the like. For example, Japanese Patent Application Laid-Open No. 2014-159154 (Patent Document 1) describes attaching an acrylic-based base-free pressure-sensitive adhesive sheet to the back surface of a resin base material and using it as a decorative pressure-sensitive adhesive sheet. According to decorative molding, it is considered that the impact on the environment can be reduced compared to applying decoration to an article by painting.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In decorative molding, the adhesive may foam during heating. Japanese Patent Application Laid-Open No. 2017-154382 (Patent Document 2) describes a decorative adhesive sheet provided with a silicone adhesive layer having a thickness of 50 μm or more as an adhesive layer in which foaming hardly occurs.

[0005] However, even when a silicone adhesive layer is provided, there may be a case where a gap occurs between the adherend and the decorative adhesive sheet.

[0006] An object of the present invention is to provide a decorative adhesive sheet that suppresses foaming from the adhesive layer and hardly causes a gap with the adherend, and an adhesive sheet used therefor.

Means for Solving the Problems

[0007] An example of the adhesive sheet disclosed in this specification is used for attaching a decorative sheet to an adherend and includes a silicone-based adhesive layer. When the storage elastic modulus of the adhesive layer under the conditions of 23°C and a frequency of 1 Hz is represented as G1’ (Pa), and the storage elastic modulus of the adhesive layer under the conditions of 100°C and 1 Hz is represented as G2’ (Pa), G2’ / G1’ is 0.3 or less.

Advantages of the Invention

[0008] According to the adhesive sheet disclosed in this specification, foaming from the adhesive layer is suppressed, and floating between the adhesive sheet and the adherend is less likely to occur.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0010] FIG. 1 is a cross-sectional view showing an example of the adhesive sheet according to an embodiment of the present disclosure. The adhesive sheet 12 shown in the figure includes a silicone-based adhesive layer 3, a first release liner 1 bonded to one surface of the adhesive layer 3, and a second release liner 5 bonded to the other surface of the adhesive layer 3. The adhesive sheet 12 is an adhesive sheet used for attaching a decorative sheet to an adherend as described later.

[0011] Since the adhesive layer 3 is formed of a cured silicone-based adhesive, it has better heat resistance than an acrylic-based adhesive layer and also tends to have higher gas permeability than an acrylic-based adhesive.

[0012] When the storage elastic modulus of the adhesive layer measured by shear measurement under the conditions of 23°C, 1 Hz, and a strain amount of 0.05% is represented as G1’ (Pa), and the storage elastic modulus of the adhesive layer measured by shear measurement under the conditions of 100°C, 1 Hz, and a strain amount of 0.05% is represented as G2’ (Pa), G2’ / G1’ is 0.3 or less. Thus, the adhesive sheet of the present embodiment becomes relatively more flexible at high temperatures, so when used as a decorative adhesive sheet, it has good followability to the adherend and is less likely to cause lifting.

[0013] The storage elastic modulus G1’ of the adhesive layer 3 under the conditions of 23°C and a frequency of 1 Hz is 5 1.0×10 7 Pa or more and may be about 1.0×10 5 Pa or less, and preferably 2.5×10 6 Pa or more and 5.0×10 5 Pa or less. When the storage elastic modulus G1’ is 1.0×10 5 Pa or more, it becomes easier to maintain a state of following a three-dimensional adherend. When an adherend is a material that easily generates outgas such as polycarbonate (PC), it is preferable to set the storage elastic modulus G1’ to 2.5×10

[0014] When the storage elastic modulus G1’ at 23°C is 1.0×10 7 Pa or less, the followability is good when the adherend has a three-dimensional shape. When the storage elastic modulus G1’ is 5.0×10 6 Pa or less, the flexibility is good, so even when unevenness occurs due to foreign matter adhering to the surface of the adherend, the surface of the molded product can be kept smooth.

[0015] The adhesive layer 3 is preferably attached with an adhesive force such that it is not easily peeled off from a resin, metal, or the like. Since the adhesive layer 3 is formed of a cured product of a silicone-based adhesive, it has higher heat resistance than cured products of rubber-based or acrylic-based adhesives, and tends to have a wider range of applicable adherend materials. The resin that can be used as the adherend material is not particularly limited, and for example, it may be PC, acrylonitrile-butadiene-styrene copolymer (ABS resin), polypropylene (PP), polyethylene (PE), or the like.

[0016] Among these materials, in recent years, an adhesive layer that can strongly adhere to PP in particular has been desired. However, in the adhesive sheet 12 of the present embodiment, the adhesive force of the adhesive layer 3 after 24 hours from the time of attachment to the adherend under the conditions of 23 °C, 50% relative humidity, 180° peel angle, and 300 mm / min peel speed with respect to a PP plate may be 10 N / 25 mm or more. Also, the adhesive force of the adhesive layer 3 after 24 hours from the time of attachment to the adherend under the conditions of 100 °C, 180° peel angle, and 300 mm / min peel speed with respect to a PP plate may be 4.0 N / 25 mm or more.

[0017] Thus, not only is the adhesive force to PP at room temperature high, but also the adhesive force to PP at high temperatures is high. Therefore, even when the adherend is made of PP, the adhesive sheet 12 can be preferably used as the adhesive layer of a decorative adhesive sheet.

[0018] The loss modulus (G'') of the adhesive layer 3 at 23 °C and a frequency of 1 Hz is, for example, 1.0×10 5 Pa or more and 1.0×10 8 Pa or less, and may be greater than 5.0×10 5 Pa and 1.0×10 7 Pa or less. The loss modulus (G'') of the adhesive layer 3 at 100 °C and a frequency of 1 Hz is, for example, 1.0×10 3 Pa or more and 5.0×10 7 Pa or less, and may be greater than 5.0×10 3 Pa and 5.0×10 6 Pa or less.

[0019] The tanδ of the adhesive layer 3 at 23°C and a frequency of 1 Hz is 1.0×10 ー1 or more, and may be 1.0×10 2 or less.

[0020] The elongation at break of the adhesive layer 3 at 23°C may be 400% or more, or may be 500% or more. The elongation at break of the adhesive layer 3 at 100°C may be greater than or less than the elongation at break of the adhesive layer 3 at 23°C.

[0021] The thickness of the adhesive layer 3 is not particularly limited. For example, it may be 5 μm or more and 100 μm or less, or may be 10 μm or more and 50 μm or less. When the thickness of the adhesive layer 3 is 5 μm or more, the adhesive force to the adherend can be increased, and even when there are irregularities on the surface of the adherend, it is easier to absorb them. When the thickness of the adhesive layer 3 is 100 μm or less, the manufacturing cost can be suppressed.

[0022] The peeling force A1 required to peel the first release liner 1 from the adhesive layer 3 may be greater than the peeling force A2 required to peel the second release liner 5 from the adhesive layer 3. With this configuration, when using the adhesive sheet 12, first peel the second release liner 5 and bond the adhesive layer 3 to the decorative sheet, and then peel the first release liner 1 and attach it to the adherend, which becomes easy.

[0023] The first release liner 1 and the second release liner 5 may each have a laminated structure in which a blocking layer and a release agent layer are formed on the surface of high-quality paper, glassine paper, etc., or may be a laminate in which a release agent layer is provided on the surface of a resin film such as polyethylene terephthalate (PET).

[0024] As environmental measures, a recycled material may be used for part or all of the material of the resin film, or a paper-made release liner that is easy to recycle and does not have a resin laminate layer on the surface may be used. Alternatively, a release liner that does not contain PFAS in the release agent layer may be used.

[0025] FIG. 2 is a cross-sectional view showing a decorative adhesive sheet using the adhesive sheet 12 shown in FIG. 1. As shown in the figure, the decorative adhesive sheet 10 of the present embodiment includes, for example, a decorative sheet 15 having a surface layer 9 and a resin sheet 7 formed on one surface of the surface layer 9, and an adhesive layer 3 formed on the surface of the resin sheet 7 opposite to the surface layer 9. And a first release liner 1 formed on the surface of the adhesive layer 3 opposite to the resin sheet 7.

[0026] As the resin sheet 7, for example, a resin such as an olefin resin, a styrene resin, or a vinyl chloride resin formed into a film shape by extrusion and stretching can be used. In the decorative adhesive sheet 10 of the present embodiment, since the adhesive layer 3 exhibits a relatively strong adhesive force to PP at both 23° C. and 100° C., the resin sheet 7 may be made of PP.

[0027] The thickness of the resin sheet 7 is not particularly limited as long as it can prevent dust and uneven shapes on the surface of the adherend from propagating to the surface layer 9 and does not excessively impair the moldability of the decorative adhesive sheet 10. The thickness of the resin sheet 7 may be, for example, 30 μm or more, 50 μm or more, or 80 μm or more, and may be 500 μm or less, 300 μm or less, or 250 μm or less.

[0028] As the surface layer 9, various resins can be used, such as ABS resin, AS resin (copolymer of acrylonitrile and styrene), acrylic resin, PET, polybutylene terephthalate, nylon, polyacetal, polyphenylene oxide, phenolic resin, urea resin, melamine resin, liquid crystal polymer, polytetrafluoroethylene, polyvinylidene fluoride, polysulfone, polyethersulfone, polyacetal, polyetheretherketone, polyphenylene sulfide, polyetherimide, polyamideimide, PC, PE, PP, polystyrene (PS), urethane resin, etc. The surface layer 9 may be a colored layer in which graphite or the like is blended with these resins. Acrylic resin, polyurethane, fluororesin and polyvinyl chloride are preferred because of their excellent weather resistance. Acrylic resin and polyurethane are more preferred because of their excellent scratch resistance and low environmental load when incinerated or landfilled as waste.

[0029] The thickness of the surface layer 9 is not particularly limited, but for example, it may be 1 μm or more, 5 μm or more, or 10 μm or more, and may also be 150 μm or less, 100 μm or less, or 80 μm or less.

[0030] Although not shown in the figure, a design layer may be provided between the resin sheet 7 and the surface layer 9. Examples of the design layer include a color layer containing a plurality of colors or a metal layer, patterns such as wood grain, stone grain, geometric patterns, leather patterns, a pattern layer for imparting a logo, a pattern, etc. to the structure, a relief layer, etc. The surface layer 9 itself may be provided as a design layer that is colored or embossed.

[0031] As described above, when the storage elastic modulus of the pressure-sensitive adhesive layer under the conditions of 23°C and 1 Hz of the pressure-sensitive adhesive layer 3 is represented as G1’ (Pa), and the storage elastic modulus of the pressure-sensitive adhesive layer under the conditions of 100°C and 1 Hz is represented as G2’ (Pa), G2’ / G1’ is 0.3 or less. The storage elastic modulus of the pressure-sensitive adhesive layer at 23°C may be 1.0×10 5 Pa or more and 1.0×10 7 Pa or less.

[0032] The adhesive strength of the pressure-sensitive adhesive layer 3 after 24 hours from attachment to the PP plate may be 10 N / 25 mm or more at 23° C., a relative humidity of 50%, a peel angle of 180°, and a peel speed of 300 mm / min. The adhesive strength of the pressure-sensitive adhesive layer 3 after 24 hours from attachment to the PP plate may be 4.0 N / 25 mm or more at 100° C., a peel angle of 180°, and a peel speed of 300 mm / min.

[0033] The decorative adhesive sheet 10 of this embodiment is preferably used for vacuum and pressure forming such as TOM forming.

[0034] FIG. 3 is a diagram showing an example of a vacuum pressure-sensitive molding device using a decorative adhesive sheet. As shown in the figure, a known vacuum pressure-sensitive molding device 30 has a first vacuum chamber 31 and a second vacuum chamber 32 on the top and bottom, respectively, and a jig for setting the decorative adhesive sheet 10 of this embodiment to be attached to the adherend 20 is provided between the top and bottom vacuum chambers. In addition, in the lower first vacuum chamber 31, a partition plate 34, a table 25, and a pedestal 33 are installed on a lifting platform 35 that can be raised and lowered up and down, and the adherend 20 having a three-dimensional shape is set on this pedestal 33. The adherend 20 is made of a resin such as PP. For example, a double-sided vacuum molding machine (manufactured by Fuse Vacuum Co., Ltd.) can be used as such a vacuum pressure-sensitive molding device 30.

[0035] During molding, first, the first vacuum chamber 31 and the second vacuum chamber 32 of the vacuum and pressure forming device 30 are opened to atmospheric pressure, and the decorative adhesive sheet 10 is set between the upper and lower vacuum chambers. The decorative adhesive sheet 10 is set with the adhesive layer 3 facing the adherend 20.

[0036] Next, the first vacuum chamber 31 and the second vacuum chamber 32 are closed, and the inside of each chamber is evacuated. Then, the decorative adhesive sheet 10 is heated. After that, the lifting platform 35 is raised to push the adherend 20 up to the second vacuum chamber 32. The heated decorative adhesive sheet 10 is pressed against the adherend 20 and stretched. Next, the second vacuum chamber 32 is filled with an appropriate pressure (0.0 Pa to 2.0×10 5By setting it to Pa), the decorative adhesive sheet 10 covers the exposed surface of the adherend 20 due to the pressure difference. Next, the first vacuum chamber 31 and the second vacuum chamber 32 are opened again to return to atmospheric pressure, and the adherend 20 covered with the decorative adhesive sheet 10 is taken out.

[0037] After that, the end of the decorative adhesive sheet 10 adhered to the adherend 20 is trimmed, and the forming process is completed.

[0038] In the adhesive layer 3 of the present embodiment, since G2’ / G1’ is 0.3 or less, molding can be performed without floating when the decorative adhesive sheet 10 is attached to the adherend 20.

Example

[0039] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[0040] - Preparation of Adhesive Sheet- Using a comma coater, a commercially available silicone-based adhesive A was applied to the release surface of the first release liner. After application, it was dried at 120 °C to form an adhesive layer with a thickness of 50 μm, and a second release liner was bonded to the exposed surface of the adhesive layer to prepare an adhesive sheet as Example 1. As the first release liner and the second release liner, commercially available release liners having a fluorine-containing release agent layer were used.

[0041] Using commercially available silicone-based adhesives B, C, D, and E, an adhesive layer with a thickness of 50 μm was formed by the above method, and adhesive sheets were prepared as Example 2, Example 3, Example 4, and Comparative Example 1, respectively. Also, as Comparative Example 2, a commercially available adhesive sheet ("Mold Fit50" manufactured by Nikkai Shinwa Co., Ltd.) was prepared. This is a substrate-less sheet in which an acrylic-based adhesive layer with a thickness of 50 μm is sandwiched between a first release liner on the heavy release side and a second release liner on the light release side.

[0042] - Preparation of Decorative Adhesive Sheet- The second release liner on the light release side of the adhesive sheets produced in Examples 1 to 4 and Comparative Examples 1 and 2 was peeled off, and the exposed adhesive layer was attached to one side of a 100 μm thick acrylic film or a 100 μm thick PP film to produce a decorative adhesive sheet.

[0043] -Preparation of molded body- The decorative adhesive sheet according to Example 3 was set in a vacuum pressure molding device manufactured by Fuse Vacuum Co., Ltd., and a three-dimensional adherend made of PP was placed on the base, and vacuum pressure molding was performed. This produced a molded body having an adherend and a decorative adhesive sheet covering the surface of the adherend. The decorative adhesive sheets according to Comparative Examples 1 and 2 were also used in vacuum pressure molding in the same manner as the decorative adhesive sheet according to Example 3, and a molded body was produced. The molding temperature was 135°C in all cases.

[0044] --Environmental testing of molded products-- Each molded body before treatment was photographed and visually evaluated for appearance. Next, an X-shaped cut was made at the top of each molded body and it was kept in a thermostatic chamber at 80°C for 168 hours. By making a cut, it becomes easier to shrink the decorative adhesive sheet, and it becomes easier to evaluate by heat treatment. After the treatment, the molded body was taken out of the thermostatic chamber and photographed, and visually evaluated for appearance.

[0045] - Adhesive strength measurement - For each test piece of pressure sensitive adhesive sheet cut to a width of 25 mm, the release liner was removed, a 25 μm thick PET film was attached to the backing, and the other release liner was removed and the piece was attached to the adherend. SUS (BA) boards, PP boards, and PE boards were used as the adherends. After being attached to the adherends, the piece was rolled back and forth once with a 2 kg rubber roller, and measurements were taken 1 minute and 24 hours later. Measurements were taken at 23°C (room temperature) and at room temperature for 48 hours, followed by transfer to a 100°C atmosphere. A TENSILON RTI-1225 manufactured by A&D Co., Ltd. was used for the measurements.

[0046] -Measurement of breaking elongation and breaking stress- The pressure-sensitive adhesive sheets prepared in Examples 1 to 4 and Comparative Example 1 and the pressure-sensitive adhesive sheet prepared in Comparative Example 2 were cut into strips having a width of 37.5 mm and a length of 30 mm, and after peeling off the release liner on the easy-peel side, while peeling off the release liner on the heavy-peel side, the adhesive layer was rolled up to form a cylindrical body having a length of 30 mm. Both ends of this cylindrical body, 5 mm each, were sandwiched between papers, and the central portion of 20 mm was exposed and set on a tensile testing machine (TENSILON RTI-1225). With both ends of the cylindrical body being gripped by the gripping tools, a tensile test was conducted at a gripping interval of 20 mm and a tensile speed of 300 mm / min in an environment of 23°C, 50% relative humidity, and 100°C, and the breaking stress and elongation at break were measured.

[0047] - Measurement of the storage elastic modulus of the pressure-sensitive adhesive sheet - The pressure-sensitive adhesive sheets prepared in Examples 1 to 4 and Comparative Example 1 and the pressure-sensitive adhesive sheet prepared in Comparative Example 2 were laminated until the total thickness reached 1 mm, and then punched into a size of 8 mm in diameter to prepare tablets. These tablets were sandwiched between the plates of a rheometer (product name: AR2000ex), and the storage elastic modulus G' and loss elastic modulus G'' were measured under the conditions of a frequency of 1 Hz and a strain amount of 0.05%, and tanδ was calculated. The temperature was measured at both 23°C and 100°C.

[0048] - Gas floating resistance test - The pressure-sensitive adhesive sheets prepared in Examples 1 to 4 and Comparative Example 1 and the pressure-sensitive adhesive sheet prepared in Comparative Example 2 were cut into square shapes of 8 mm square to obtain test pieces. After peeling off the release liner on the easy-peel side of each test piece and bonding the exposed surface to a polycarbonate (PC) plate with a thickness of 3 mm, the release liner on the heavy-peel side was peeled off and a PET film with a thickness of 100 μm was bonded to the exposed surface. These test pieces were treated in an autoclave under the conditions of 0.5 MPa and 50°C for 30 minutes, and then left standing at 23°C and normal pressure (about 101 kPa) for 24 hours to be adhered to the PC plate. Subsequently, the test pieces adhered to the PC plate were subjected to a treatment at 85°C for 240 hours (heat resistance test) or a treatment at 60°C and 95% relative humidity for 240 hours (humid heat resistance test) in a testing machine, and then taken out from the testing machine, and the state of each test piece was visually or microscopically confirmed at 23°C.

[0049] - Measurement Results - Table 1 shows the results of the adhesive strength measurement tests of the pressure-sensitive adhesive sheets prepared in Examples 1 to 4, Comparative Example 1, and the pressure-sensitive adhesive sheet prepared in Comparative Example 2. In Table 1, as the measured value of the adhesive strength, except for the case of dipping, the average value of three examples is shown. In the case of dipping, the lower limit value and the upper limit value of the measured adhesive strength are described and denoted as "zip".

[0050]

Table 1

[0051] Also, in the pressure-sensitive adhesive sheets prepared in Examples 1 to 4, the adhesive strength against the PP plate at 100°C was 4.0 N / 25 mm or more, maintaining a relatively high adhesive strength. On the other hand, in the pressure-sensitive adhesive sheet prepared in Comparative Example 1, the adhesive strength against the PP plate at 100°C was as small as 3.4 N / 25 mm.

[0052] It was confirmed that in the pressure-sensitive adhesive sheets prepared in Examples 1 to 4, the breaking stress was greater than that of the pressure-sensitive adhesive sheet prepared in Comparative Example 1 and the pressure-sensitive adhesive sheet prepared in Comparative Example 2 under both conditions of 23°C and 100°C.

[0053] Regarding the storage modulus at 23°C, the pressure-sensitive adhesive sheets prepared in Examples 1 to 4 showed higher values than the pressure-sensitive adhesive sheet prepared in Comparative Example 1 and the pressure-sensitive adhesive sheet prepared in Comparative Example 2. Also, in the pressure-sensitive adhesive sheets according to Examples 1 to 4, when the storage modulus of the adhesive layer under the conditions of 23°C and a frequency of 1 Hz is represented as G1' (Pa) and the storage modulus of the adhesive layer under the conditions of 100°C and 1 Hz is represented as G2' (Pa), G2' / G1' was 0.3 or less, whereas in the pressure-sensitive adhesive sheet according to Comparative Example 1, G2' / G1' was 0.55.

[0054] Figure 4 is a photographic view showing the results of performing TOM molding using a decorative adhesive sheet provided with the adhesive sheets prepared in Example 3 and Comparative Example 1 and the adhesive sheet prepared in Comparative Example 2, respectively.

[0055] As shown in the figure, when using the decorative adhesive sheets provided with the adhesive sheets prepared in Examples 1 to 4 and Comparative Example 1 and an acrylic film, it was confirmed that the decorative adhesive sheet followed the unevenness of the adherend well and no lifting or peeling occurred. There was also no change when held at 80°C after molding. On the other hand, when using the adhesive sheet prepared in Comparative Example 2, slight heat shrinkage was observed at the cut portion after holding at 80°C after molding.

[0056] When using the decorative adhesive sheets provided with the adhesive sheets prepared in Examples 1 to 4 and a PP film, no lifting from the adherend was observed before the test, and there was only a slight lifting at the end and valley portions even after 168 hours at 80°C. On the other hand, when using the decorative adhesive sheets provided with the adhesive sheets according to Comparative Examples 1 and 2 and a PP film, slight lifting was observed at the end and valley portions before the test, and large lifting occurred after 168 hours at 80°C.

[0057] Regarding the adhesive sheets prepared in Examples 1 and 3, no bubbles were observed in both the heat resistance test and the damp heat resistance test, and it was confirmed that they had very excellent gas floating resistance performance. Regarding the adhesive sheet prepared in Example 2, although small bubbles of about 0.3 mm were slightly observed in the heat resistance test, no bubbles were observed in the damp heat resistance test, and it was confirmed that it had excellent gas floating resistance performance that could withstand practical use. On the other hand, in the adhesive sheets prepared in Example 4 and Comparative Example 1 and the adhesive sheet prepared in Comparative Example 2, large bubbles were generated in the heat resistance test and bubbles were also observed in the damp heat resistance test, indicating that the gas floating resistance performance was insufficient. From the results in Table 1, the adhesive sheets according to Examples 1, 2, and 3 all had a storage elastic modulus G1' at 23°C and 1 Hz of 2.5×10 5 Pa or more, so that the storage elastic modulus G1' was 2.5×10 5It was considered that the gas floating resistance was better than that of the pressure-sensitive adhesive sheets according to Example 4, Comparative Examples 1 and 2 with Pa less than. In the damp heat resistance test, whitening due to moisture was observed in all the test pieces, but when left standing for 24 hours in an environment of 23 ° C and 50% relative humidity, the whitening disappeared in all the test pieces. Therefore, it was considered that the occurrence of whitening would not be a major problem in actual use.

Industrial Applicability

[0058] The pressure-sensitive adhesive sheet of the present disclosure can be used for decoration of vehicle parts such as automobiles, household appliances, daily necessities, railways, and building materials.

Explanation of Symbols

[0059] 1 First release liner 3 Adhesive layer 5 Second release liner 7 Resin sheet 9 Surface layer 10 Decorative pressure-sensitive adhesive sheet 12 Pressure-sensitive adhesive sheet 15 Decorative sheet 20 Adherend 30 Vacuum pressure air forming device

Claims

1. An adhesive sheet used for attaching a decorative sheet to an adherend, comprising a silicone-based adhesive layer, wherein when the storage elastic modulus of the adhesive layer under the conditions of 23°C and a frequency of 1 Hz is represented as G1' (Pa), and the storage elastic modulus of the adhesive layer under the conditions of 100°C and 1 Hz is represented as G2' (Pa), the adhesive sheet has G2' / G1' of 0.3 or less.

2. The storage elastic modulus G1' of the pressure-sensitive adhesive layer at 23°C and a frequency of 1 Hz is 1.0×10 ５ Pa or more and 1.0×10 ７ Pa or less. The pressure-sensitive adhesive sheet according to claim 1.

3. The storage elastic modulus G1' of the pressure-sensitive adhesive layer at 23°C and a frequency of 1 Hz is 2.5×10 ５ Pa or more and 5.0×10 ６ Pa or less. The pressure-sensitive adhesive sheet according to claim 2.

4. The adhesive sheet according to any one of Claims 1 to 3, wherein the adhesive force of the adhesive layer under the conditions of 100°C, a peeling angle of 180 degrees, and a peeling speed of 300 mm / min after 24 hours from the attachment to a polypropylene plate is 4.0 N / 25 mm or more.

5. A decorative adhesive sheet comprising a decorative sheet having a resin sheet, and an adhesive layer attached to one surface of the resin sheet, wherein when the storage elastic modulus of the adhesive layer under the conditions of 23°C and 1 Hz is represented as G1' (Pa), and the storage elastic modulus of the adhesive layer under the conditions of 100°C and 1 Hz is represented as G2' (Pa), the decorative adhesive sheet has G2' / G1' of 0.3 or less.

6. The decorative adhesive sheet according to Claim 5, wherein the resin sheet contains polypropylene as a main material.

7. The storage elastic modulus of the adhesive layer at 23°C is 1.0×10 ５ Pa or more and 1.0×10 ７ Pa or less. The decorated adhesive sheet according to claim 5.

8. The decorative adhesive sheet according to any one of Claims 5 to 7, wherein the adhesive force of the adhesive layer under the conditions of 100°C, a peeling angle of 180 degrees, and a peeling speed of 300 mm / min after 24 hours from the attachment to a polypropylene plate is 4.0 N / 25 mm or more.

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