JP2023046642A - Pressure sensitive adhesive sheet, method for manufacturing the same, and method for measuring adhesion force - Google Patents

Abstract

To provide: a pressure sensitive adhesive sheet having excellent reworkability; a method for manufacturing the sheet; and a method for measuring adhesion force.SOLUTION: A pressure sensitive adhesive sheet sequentially includes a substrate layer, an adhesive layer, and a releasable sheet layer. The adhesive layer is porous. An adhesion force A between the substrate layer and the adhesive layer is 17.0 N/25 mm or more, and an adhesion force B between the adhesive layer and an SUS304 steel sheet is 1.0-10.0 N/25 mm. A method for manufacturing the pressure sensitive adhesive sheet, and a method for measuring adhesion force are provided.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present disclosure relates to a pressure-sensitive adhesive sheet, a method for producing the same, and a method for measuring adhesion.

Conventionally, decorative sheets have been used to decorate and protect the surfaces of, for example, interior and exterior members of buildings, fittings or fixtures, decorative surface panels, and interior or exterior members of vehicles. .

After the decorative sheet is attached to the adherend, it is required to adhere to the adherend for a long period of time without lifting or peeling off from the adherend. Therefore, it is necessary for the decorative sheet to have a strong adhesive strength by providing an adhesive layer composed of an adhesive on the entire surface of the decorative sheet that comes into contact with the adherend. On the other hand, if the decorative sheet has a strong adhesive force, it becomes difficult to re-use the decorative sheet by peeling and re-applying it to the adherend. For example, if wrinkles occur during application, they cannot be repaired, and the decorative sheet once applied to the adherend has to be peeled off and discarded. Further, when the adherend is reused, it is necessary to remove the adhesive (also referred to as "adhesive residue") remaining on the surface of the adherend when the decorative sheet is peeled off.

As described above, the decorative sheet provided with a strong adhesive force by the adhesive layer has a strong adhesive force. Therefore, special equipment and skilled techniques are required in the production and application of the decorative sheet using the decorative sheet. becomes. Therefore, the production and application of the decorative materials are highly difficult tasks.
Therefore, in order to make the decorative sheet easier to use, it has been desired to maintain the required long-term adhesion and improve the reworkability so that if the application fails, the sheet can be peeled off and applied again as it is. .

For example, in Patent Document 1, a primer containing a foaming agent is heated and foamed on one side or both sides of a base sheet made of a soft synthetic resin as a pressure-sensitive adhesive sheet that eliminates adhesive residue while improving adhesiveness. There have been proposed a primer layer having unevenness due to air bubbles or broken air bubbles on its surface, and a pressure-sensitive adhesive sheet obtained by laminating a pressure-sensitive adhesive layer on a primer layer.
Further, in Patent Document 2, as a pressure-sensitive adhesive sheet having excellent interlaminar adhesion and removability with little adhesive residue, a specific aqueous polyester primer layer is provided between the base material layer and the pressure-sensitive adhesive layer. A pressure-sensitive adhesive sheet having a primer layer formed from a forming composition containing a base resin has been proposed.

JP-A-7-145354 JP 2016-94517 A

The pressure-sensitive adhesive sheets proposed in Patent Documents 1 and 2 have excellent adhesion to adherends (referred to as "adhesiveness" and "interlayer adhesion" in each document), and have adhesive properties. It is said to be an adhesive sheet with excellent reworkability with little residue.
However, both the pressure-sensitive adhesive sheets described in Patent Documents 1 and 2 have room for improvement in the primer layer for exhibiting adhesion to the adherend. That is, the pressure-sensitive adhesive sheet described in Patent Document 1 requires a step of foaming the primer layer by heating in the production stage, and the pressure-sensitive adhesive sheet described in Patent Document 2 contains a resin composition that forms the primer layer. Special. Therefore, there is a problem that productivity is inferior or versatility is lacking.

By the way, the excellent reworkability is due to the fact that the decorative sheet is exposed to high temperatures such as direct sunlight and harsh environments such as outdoor exposure during the period from adhesion to an adherend until it is peeled off. Even if it is supposed to be requested. Moreover, excellent reworkability is now required for any adherend regardless of the type of adherend. Thus, in recent years, the reworkability of pressure-sensitive adhesive sheets has been required to be more and more advanced.
However, the pressure-sensitive adhesive sheets proposed in Patent Documents 1 and 2 do not have such high reworkability.

Accordingly, an object of the present disclosure is to provide a pressure-sensitive adhesive sheet having excellent reworkability, a method for producing the same, and a method for measuring adhesion.

As a result of intensive studies to solve the above problems, the present inventors have found that in a pressure-sensitive adhesive sheet having a substrate layer, an adhesive layer, and a peelable sheet layer, the adhesive layer is a porous layer, and the substrate layer and the adhesive It has been found that the above problem can be solved by setting the adhesion strength between the layer and the adhesion strength between the adhesive layer and a predetermined SUS304 steel plate within a predetermined range. That is, in order to solve the above problems, the present disclosure provides the following adhesive sheet;
Having a substrate layer, an adhesive layer, and a peelable sheet layer in this order,
The adhesive layer is porous,
Adhesion A between the base material layer and the adhesive layer measured by a predetermined measuring method is 17.0 N/25 mm or more,
The adhesive strength B between the adhesive layer and the SUS304 steel plate measured by a predetermined measuring method is 1.0 N / 25 mm or more and 10.0 N / 25 mm or less.
adhesive sheet,
I will provide a.

In addition, the present disclosure provides the following adhesive sheet manufacturing method;
an adhesive coating layer forming step of applying an adhesive layer-forming resin composition onto the releasable surface of the release sheet layer to form an adhesive coating layer of the adhesive layer-forming resin composition;
An adhesive layer forming step of drying the adhesive coating layer to form an adhesive layer that is porous;
including,
Adhesion A between the base material layer and the adhesive layer measured by a predetermined measuring method is 17.0 N/25 mm or more,
The adhesive strength B between the adhesive layer and the SUS304 steel plate measured by a predetermined measuring method is 1.0 N / 25 mm or more and 10.0 N / 25 mm or less.
A method for producing an adhesive sheet,
I will provide a.

Furthermore, the present disclosure provides the following method for measuring adhesion;
(i) For the adhesive sheet having a base layer and an adhesive layer, SUS304 in accordance with JIS Z0237: 2009 (Testing methods for adhesive tapes and adhesive sheets) Method 3 (180 ° peeling adhesive strength of double-sided tape) A steel plate and the adhesive layer of the adhesive sheet (width: 25 mm, length: 100 mm) are attached via a double-sided adhesive tape, and after 1 hour from the attachment, the base is measured using a peel strength measuring instrument. 180° peeling (peel rate: 300 mm / min) so that the material layer and the adhesive layer are peeled off, and measuring the adhesion strength A method for measuring the adhesion strength A of the adhesive sheet,
(ii) For the adhesive sheet having at least an adhesive layer, in accordance with JIS Z0237: 2009 (Testing methods for adhesive tapes and adhesive sheets) Method 1 (180° peeling adhesive strength to test plate), SUS304 steel plate, An adhesive sheet (width: 25 mm, length: 100 mm) is attached, and immediately after attachment and 24 hours after attachment, the adhesive sheet is peeled off at 180° using a peel strength measuring instrument ( Peeling speed: 300 mm / min) and measuring the adhesion force, a method for measuring the adhesion force B,
I will provide a.

ADVANTAGE OF THE INVENTION According to this indication, the adhesive sheet which has the outstanding reworkability, its manufacturing method, and the measuring method of adhesive force can be provided.

1 is a cross-sectional view showing an embodiment of a pressure-sensitive adhesive sheet of the present disclosure; FIG. 1 is a cross-sectional view showing an embodiment of a base layer of a pressure-sensitive adhesive sheet of the present disclosure; FIG. 1 is a cross-sectional view showing an embodiment of a base layer of a pressure-sensitive adhesive sheet of the present disclosure; FIG.

Hereinafter, the pressure-sensitive adhesive sheet according to the present disclosure and the method for producing the same will be specifically described. It should be noted that the present disclosure is not limited to the following embodiments, and can be arbitrarily modified within a range that does not impair the effects of the invention.
In addition, in this specification, numerical values related to “greater than”, “less than or equal to” and “to” in describing numerical ranges are numerical values that can be arbitrarily combined. For example, when a numerical range is described as "A to B" and "C to D", numerical ranges such as "A to D" and "C to B" are also included.

[Adhesive sheet]
The adhesive sheet of the present disclosure has a substrate layer, an adhesive layer, and a peelable sheet layer in this order,
The adhesive layer is porous,
The adhesive strength A between the base material layer and the adhesive layer measured by the following measuring method is 17.0 N/25 mm or more,
The adhesion strength B between the adhesive layer and the SUS304 steel plate measured by the following measuring method is 1.0 N/25 mm or more and 10.0 N/25 mm or less.

(Method for measuring adhesion A)
JIS Z0237: 2009 (Testing methods for adhesive tapes and adhesive sheets), Method 3 (180° peeling adhesive strength of double-sided tape), SUS304 steel plate and the adhesive sheet (width: 25 mm, length: 100 mm) The adhesive layer is attached via a double-sided adhesive tape, and 1 hour after attachment, a peel strength measuring instrument is used to peel off the base layer and the adhesive layer at 180 ° ( Peeling speed: 300 mm/min.
(Method for measuring adhesion B)
In accordance with JIS Z0237: 2009 (testing methods for adhesive tapes and adhesive sheets), method 1 (180° peeling adhesive strength to test plate), the adhesive sheet (width: 25 mm, length: 100 mm) was applied to a SUS304 steel plate. is attached, immediately after attachment, and 24 hours after attachment, the adhesive sheet is peeled off 180 ° using a peel strength measuring instrument (peeling speed: 300 mm / min) and measured. Adhesion strength is defined as adhesion strength B.

The pressure-sensitive adhesive sheet of the present disclosure has an adhesion strength B between the pressure-sensitive adhesive layer and the SUS304 steel plate of 1.0 N/25 mm or more and 10.0 N/25 mm or less. The adhesive strength B is the adhesive strength measured immediately after the adhesive layer and the SUS304 steel plate are attached (also referred to as “initial adhesive strength B ₁ ”), and the adhesive strength measured 24 hours after attachment ( Also referred to as “normal adhesion B ₂ ”). That is, the fact that the adhesion strength B of the pressure-sensitive adhesive sheet of the present disclosure is 1.0 N/25 mm or more and 10.0 N/25 mm or less means that both the initial adhesion strength _B1 and normal adhesion strength _B2 are 1.0 N/25 mm or more and 10 0 N/25 mm or less.

As will be shown in Examples described later, the normal state adhesion _B2 is slightly increased compared to the initial adhesion _B1 , and thereafter hardly decreases over time. Such a tendency can be said to be one of the major characteristics of the adhesive layer being porous. Therefore, it is considered that the adhesive strength B indicates the adhesive strength between the pressure-sensitive adhesive sheet of the present disclosure and an adherend over a medium to long period from immediately after application. Here, "medium and long term" means a period of 24 hours (1 day) to several years (about 10 years). Further, the "slightly increased" adhesion force means that the increase width is 10% or less.

Since the adhesion strength A is the adhesion strength measured by peeling after 1 hour from adhesion, it can be said that the adhesion strength B corresponds to the normal adhesion strength _B1 of the adhesion strength B described above. The adhesive strength A is the adhesive strength between the base material layer and the adhesive layer after a certain period of time has passed since the adhesive sheet of the present disclosure was produced, so the adhesive strength is already stable. 30 minutes after sticking, variation occurs and it is not stable. Therefore, with regard to the adhesion A, the adhesion after one hour from the application is taken as the normal adhesion _A1 , and applied to the adhesion A.

Judging from the size of the adhesive strength B, the adhesive sheet of the present disclosure cannot generally be said to have a large adhesive strength with an adherend. Therefore, when the sticking fails, it becomes easy to peel off and stick again as it is. In addition, as described above, the adhesive strength hardly decreases even after medium- to long-term use. It has sufficient adhesion to withstand the use of Thus, the pressure-sensitive adhesive sheet of the present disclosure maintains the required long-term adhesiveness, and has excellent reworkability that, when pasting fails, it can be peeled off and pasted again.

On the other hand, if attention is paid only to the adhesive force B, when the adhesive sheet fails to adhere and is peeled off, the adhesive sheet may cause delamination, for example, between the base material layer and the adhesive layer, leaving an adhesive residue. It may be the cause. Therefore, in the present disclosure, attention is also paid to the adhesive strength A between the base material layer and the adhesive layer.
The adhesive sheet of the present disclosure has an adhesive strength A of 17.0 N/25 mm or more between the substrate layer and the adhesive layer. That is, the pressure-sensitive adhesive sheet of the present disclosure requires that the adhesion strength A between the substrate layer and the pressure-sensitive adhesive layer is greater than the adhesion strength B between the pressure-sensitive adhesive layer and the SUS304 steel plate. By having such an adhesive strength A, the adhesive sheet of the present disclosure does not cause cohesive failure in the adhesive layer when the adhesive sheet is peeled off due to failure in sticking, and the adhesive layer and the adherend do not cause cohesive failure. Delamination due to interfacial failure at Therefore, the occurrence of adhesive residue is suppressed, and the peeled pressure-sensitive adhesive sheet can be reused by sticking it again as it is.

As described above, the adhesive strength B is the adhesive strength between the adhesive layer and the SUS304 steel plate, and the SUS304 steel plate is assumed as the adherend to which the adhesive sheet is attached. The adhesive strength between the adhesive sheet and the adherend may vary depending on the material of the adherend. Therefore, even if the adhesion strength A and the adhesion strength B are set within the above-described predetermined ranges, it is conceivable that excellent reworkability may not be obtained in some cases. However, as verified in the examples described later, the adhesive strength to various adherends is measured, but there is no adherend exceeding 17.0 N / 25 mm, which is the minimum value of the adhesion strength A. .

Therefore, even if the adhesive strength B is the adhesive strength between the adhesive layer and the SUS304 steel plate, there is no influence on the superiority or inferiority of the reworkability. Further, when measuring the adhesive force B, the measured value of the adhesive force B is stabilized by adopting a predetermined SUS304 steel plate as the adherend. Therefore, the difference between the adhesion strength A and the adhesion strength B can be determined more reliably, and excellent reworkability can be obtained.

In the pressure-sensitive adhesive sheet of the present disclosure, the adhesion strength A and the adhesion strength B can be adjusted mainly by the pressure-sensitive adhesive layer. Specifically, the adhesive layer is a layer that exerts adhesive strength, but needs to be porous. That is, in the pressure-sensitive adhesive sheet of the present disclosure, it is possible to adjust the adhesion strength A and the adhesion strength B by adopting a porous layer as the pressure-sensitive adhesive layer. In addition, in the pressure-sensitive adhesive sheet of the present disclosure, the adjustment of the adhesion force A and the adhesion force B may be performed by adopting a layer that is porous at least as the adhesion layer. It is also possible to determine the type of resin that constitutes , the additive to the adhesive, and the lamination pressure when the substrate layer and the adhesive layer are adhered in the method of manufacturing the adhesive sheet.
The adhesive layer and other details in adjusting the adhesion will be described later.

Adhesion A is required to be 17.0 N/25 mm or more, preferably 17.5 N/25 mm or more, more preferably 18.0 N/25 mm or more in order to obtain better reworkability. The upper limit is not particularly limited in order to obtain better reworkability, but considering the ease of forming an adhesive layer, etc., it is preferably 30.0 N / 25 mm or less, more preferably 28.0 N / 25 mm Below, more preferably 25.0 N/25 mm or less, still more preferably 24.0 N/25 mm or less.
In the method for measuring adhesion A, the double-sided adhesive tape used for measuring adhesion A is the adhesion between the double-sided adhesive tape and the SUS304 steel plate, the adhesion between the base layer and the adhesive layer, and the double-sided adhesive tape As long as the adhesive is stronger than the adhesive force between the adhesive layer and the adhesive layer, it can be used without any particular limitation, and may be used by appropriately selecting from commercially available products.

Adhesion B is required to be 1.0 N/25 mm or more and 10.0 N/25 mm or less, and is preferably 1.5 N/mm or more, more preferably 2.0 N, in order to obtain better reworkability. /25 mm or more, more preferably 2.5 N/25 mm or more, and the upper limit is preferably 6.0 N/25 mm or less, more preferably 4.5 N/25 mm or less, still more preferably 3.5 N/25 mm or less, and even more preferably is 3.0 N/25 mm or less.

[Adhesive layer]
In the adhesive sheet of the present disclosure, the adhesive layer is a porous layer. The porous adhesive layer is a layer composed of a resin portion made of an adhesive that forms the adhesive layer and pores.
When the adhesive layer is a porous layer, the contact area between the adhesive layer and the adherend can be appropriately maintained, so excessive increase or decrease in the adhesion force B is suppressed to be within the predetermined range. easier. As a result, the adhesive sheet does not float or peel off from the adherend, and it is possible to ensure that the adhesive sheet can be easily peeled off while having sufficient adhesive strength to withstand medium- to long-term use.
On the other hand, in the relationship between the adhesive layer and the base layer, if the adhesive layer is a porous layer, the lamination pressure and the like in laminating the base layer and the adhesive layer in the manufacturing process of the adhesive sheet of the present disclosure can be adjusted. As a result, the adhesion force A is easily set within the predetermined range above the adhesion force B. As a result, the adhesion force A can be reliably made larger than the force required for peeling the adhesive sheet, and the occurrence of adhesive residue can be suppressed without cohesive peeling of the adhesive layer.
In this way, the pressure-sensitive adhesive sheet of the present disclosure has a porous pressure-sensitive adhesive layer, so that the adhesive strengths A and B are within a predetermined range, resulting in excellent reworkability.

Cross-sectional view 1 in plan view showing an embodiment of the pressure-sensitive adhesive sheet of the present disclosure has a substrate layer 2, an adhesive layer 3, and a peelable sheet layer 4, and the adhesive layer may have pores. It is shown.
As shown in FIG. 1, the pores possessed by the adhesive layer include (i) spherical pores 31 and (ii) the surface of the adhesive layer, that is, the interface with the substrate layer and the interface with the release sheet layer. Concave shapes 32 formed on the surface, and combinations of (i) spherical holes 31 and (ii) concave shapes 32 may be mentioned.

The form of (i) spherical pores and (ii) concave shapes, or a combination thereof can be easily obtained, for example, by forming the adhesive layer from an adhesive resin composition containing air bubbles. That is, in order to form the pores of the adhesive layer in the form of (i) spherical pores and (ii) concave shapes, or a combination thereof, the adhesive layer uses an adhesive resin composition containing air bubbles. It is preferable to form In addition, only by including air bubbles in the adhesive resin composition, pores such as (i) spherical pores and (ii) concave shapes can be formed, so that a porous adhesive layer can be formed. , the formation of the adhesive layer is extremely easy.

When the adhesive layer is formed from an adhesive resin composition containing air bubbles, the above (i) spherical pores are formed by the bubbles becoming pores as they are, and (ii) the concave shape is formed on the surface of the adhesive layer, That is, it is formed by the bursting of air bubbles at the interface with the base material layer, the interface with the peelable sheet layer, and in the vicinity thereof.
In the pressure-sensitive adhesive sheet of the present disclosure, it is preferable that the pores have (ii) the concave shape. This is because the adhesive force between the base material in contact with the adhesive layer and the adherend in contact with the adhesive layer when using the adhesive sheet of the present disclosure can be easily set within the predetermined range of each of the adhesive strengths A and B. . Also, for the same reason, (ii) the concave shape is preferably evenly present on the surface of the adhesive layer, that is, on the interface with the base material layer and the interface with the release sheet layer.

Regarding (ii) that the concave shapes are evenly present, more specifically, it is preferable that the following conditions are satisfied.
^Dave ₁ is the average value of the diameters of the concave openings present on the substrate side surface of the adhesive layer, and the surface of the release sheet layer opposite to the substrate layer side surface (the adhesive sheet is When D ^ave ₂ of each of the concave openings present in the surface of the substrate, it is preferable that the following condition (1) is satisfied.
|D ^ave ₁ −D ^ave ₂ |/D ^ave ₂ ≦0.5 (1)
Regarding the condition (1), |D ^ave ₁ −D ^ave ₂ |/D ^ave ₂ ≦0.25 is more preferable, and |D ^ave ₁ −D ^ave ₂ |/D ^ave ₂ ≦0.15 is even more preferable. .

When the pores of the adhesive layer have (i) spherical pores, the average diameter D ^ave ₃ of the spherical pores preferably satisfies the following condition (2).
^Dave ₁ ≤ ^Dave ₃ ≤ ^Dave ₂ or ^Dave ₂ ≤ ^Dave ₃ ≤ ^Dave ₁ (2)

Regarding the above conditions (1) and (2), the average values of the diameters D ^ave ₁ , D ^ave ₂ , and D ^ave ₃ of each opening, etc., for all concave openings and spherical holes are calculated. It is practically impossible to ask. Therefore, within the observation range of 1500 μm × 1100 μm, diameters were measured at three locations in order from the concave opening with the largest diameter and the spherical hole, and the average value was taken as the average value of the diameter of each opening. .

Among the pores of the adhesive layer, (ii) the concave shape satisfies the condition (1), so that the physical properties of the adhesive layer can be made more uniform, so that the adhesiveness can be easily made more uniform over the entire surface of the adhesive layer. . Therefore, after using the substrate layer, the peelable sheet layer, and the pressure-sensitive adhesive sheet, the adhesive strengths A and B can be uniformly exhibited with respect to the adherend, thereby improving the reworkability.
Further, among the pores of the adhesive layer, (i) spherical pores satisfy the condition (2), as well as the condition (1), because the physical properties of the adhesive layer can be made more homogeneous. improve sexuality.

The average values of (i) the diameter of the spherical pores and (ii) the diameter of the concave openings are not particularly limited as long as the above conditions (1) and (2) are satisfied. Although it cannot be generalized because it varies depending on the thickness, it is usually 1 μm or more and 300 μm or less. Considering the improvement of reworkability, it is preferably 3 μm or more, more preferably 5 μm or more, and still more preferably 10 μm or more, and the upper limit is preferably 250 μm or less, more preferably 200 μm or less, further preferably 100 μm or less.

Considering the improvement of reworkability, the density of the adhesive layer is preferably 0.1 g/cm ³ or more, more preferably 0.2 g/cm ³ or more, and still more preferably 0.3 g/cm ³ or more. It is preferably 0.8 g/cm ³ or less, more preferably 0.7 g/cm ³ or less, and even more preferably 0.6 g/cm ³ or less.

The thickness of the adhesive layer is preferably 10 µm or more, more preferably 15 µm or more, even more preferably 18 µm or more, and even more preferably 20 µm or more. When the thickness of the adhesive layer is within the above range, the above (ii) recessed shape is particularly easily formed, and a sufficient diameter of the opening can be obtained, thereby improving reworkability.
On the other hand, the upper limit of the thickness of the adhesive layer is preferably 100 µm or less, more preferably 85 µm or less, still more preferably 75 µm or less, and even more preferably 70 µm or less. When the upper limit of the thickness of the adhesive layer is within the above range, the thickness of the adhesive sheet of the present disclosure can be suppressed, so that the operations of attaching, peeling, and re-attaching the adhesive sheet become easier, and as a result, rework. improve sexuality. In addition, since handling and storage in each work place become easy, usability is improved.

(Resin composition for forming adhesive layer)
The resin composition used for forming the adhesive layer (hereinafter also referred to as "adhesive layer-forming resin composition") can be a porous adhesive layer, and the adhesion strengths A and B can be employed without particular limitation as long as it is a resin composition that satisfies As the adhesive layer-forming resin composition, an adhesive resin composition containing air bubbles is preferable as described above.

The adhesive resin composition containing air bubbles is preferably a resin composition containing an adhesive resin, a salt, and, if necessary, a solvent and various additives.

Examples of adhesive resins include urethane rubber, styrene-butadiene polymer (styrene-butadiene rubber), polyisoprene, natural rubber, acrylonitrile-butadiene rubber, ethylene-propylene rubber (EPR), ethylene-propylene-diene terpolymer rubber ( EPDM), polynorbornene, polybutadiene, nitrile rubber, chloroprene rubber, butyl rubber, halogenated butyl rubber, ethylene-vinyl acetate rubber (EVA), silicone rubber, fluororubber, ethylene acrylic rubber, polyester elastomer, epichlorohydrin rubber, polysulfide rubber, etc. Rubber-based resin; various adhesive resins such as acrylic polymer, polyurethane, chlorinated polyethylene, polyethylene, polystyrene, polyimide, polyvinyl chloride, and polypropylene; various thermoplastic elastomers such as polyolefin, polyurethane, polyester, polyamide, and polystyrene etc. are preferably mentioned. By employing these resins, it is easy to form a porous adhesive layer, and it is easy to satisfy the adhesion strengths A and B, so that reworkability is improved.

The rubber-based resin may be liquid or solid, and a mixture thereof may be used. Further, the above resin may be either a homopolymer or a copolymer, or a mixture thereof.
Among the resins described above, acrylic polymer and styrene-butadiene polymer are preferable as the adhesive resin. In addition, in the adhesive resin composition, the resin may be used singly or in combination.

The weight average molecular weight of the adhesive resin is preferably 250,000 or more, more preferably 260,000 or more, still more preferably 270,000 or more, and the upper limit is preferably 12,000,000 or less, more preferably 10,000,000 or less, more preferably 8,000,000 or less. When the weight-average molecular weight of the resin is within the above range, the adhesive layer is likely to be porous, and the adhesion strengths A and B are easily satisfied, thereby improving reworkability.
The weight average molecular weight in this specification is the average molecular weight measured by GPC analysis and converted with standard polystyrene.

Various salts such as inorganic salts and organic salts can be used as the salt.
Inorganic salts include sulfates, sulfites, carbonates, hydrogencarbonates and nitrates of metals such as sodium, magnesium, aluminum, potassium, calcium, iron, nickel, copper, zinc, silver, lead, tin and barium. , nitrites, chlorates, hypochlorites, chlorites, perchlorates, permanganates, chromates, phosphates, hydrogen phosphates, chlorides, bromides, iodides; Further, for example, ammonium sulfate, ammonium carbonate, ammonium hydrogencarbonate, ammonium nitrate, ammonium chloride, potassium aluminum sulfate (alum) and the like are preferable.

Organic salts include formates, acetates, propanoates, butanoates of metals such as sodium, magnesium, aluminum, potassium, calcium, iron, nickel, copper, zinc, silver, lead, tin and barium. Carboxylate having 1 to 18 carbon atoms such as pentanoate; and ammonium salt of carboxylic acid having 1 to 18 carbon atoms.
In addition to the above, examples of organic salts include ionic liquids such as ammonium-based, pyridinium-based, imidazolium-based, pyrrolidinium-based, choline-based, phosphonium-based, sulfonium-based, and pyrazolium-based ionic liquids.
As the inorganic salts and organic salts, the above-exemplified ones can be used singly or in combination.

In the adhesive layer-forming resin composition, the content of the salt with respect to 100 parts by mass of the adhesive resin is preferably 1 part by mass or more, more preferably 1.3 parts by mass or more, and still more preferably 3 parts by mass or more, Even more preferably 5 parts by mass or more, particularly preferably 6.0 parts by mass or more, the upper limit is preferably 80 parts by mass or less, more preferably 50 parts by mass or less, still more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, particularly preferably 10 parts by mass or less.

In addition, the adhesive resin composition for forming an adhesive may contain a solvent in consideration of the easiness of its coating, that is, the easiness of forming an adhesive layer.
Either water or an organic solvent can be used as the solvent.

Examples of water include distilled water, tap water, deionized water, carbonated water, and water purified by other known purification treatments.
Examples of organic solvents include water-miscible solvents such as methanol, ethanol, propanol, butanol, ethylene glycol, tetrahydrofuran, acetone, acetonitrile, dimethylformamide, triethylamine, pyridine, dimethylsulfoxide, diethyl ether, and ethyl acetate; , carbon tetrachloride, chloroform, dichloromethane, dichloroethane, benzene, toluene, xylene, cyclohexane, pentane, hexane, nitromethane, carbon disulfide, and other water-immiscible solvents.

Among the above, water, ethanol, and hexane are preferred, and water is more preferred. These solvents are readily available, inexpensive, and easy to evaporate, so that the adhesive layer can be formed more quickly.

The content of the solvent in the adhesive resin composition for forming an adhesive is preferably 10% by mass or more, more preferably 20% by mass or more, and still more preferably 30% by mass, based on the total amount of the adhesive resin and solvent. % or more, more preferably 40 mass % or more, and the upper limit is preferably 80 mass % or less, more preferably 70 mass % or less, and even more preferably 60 mass % or less.

Other additives can be appropriately selected and used according to the desired performance. foam inhibitor, foam breaker), emulsifier, dispersant, wetting agent, propellant, thickener, curing agent, cross-linking agent, polymerization initiator, colorant (pigment, dye), plasticizer, adhesive, filler , antifouling agents, viscoelasticity modifiers, rust inhibitors, slip agents, dryers, stabilizers, ultraviolet absorbers, antibacterial agents, antifungal agents, flame retardants and the like.
Among these, surfactants, foam stabilizers, foaming agents (foaming agents), foaming aids, and foam stabilizers are preferably used, considering that the adhesive resin composition is likely to contain air bubbles. .

The content of other additives may be appropriately set according to the desired performance, and is not particularly limited. is 0.5 parts by mass or more, and the upper limit is preferably 10 parts by mass or less, more preferably 8.5 parts by mass or less, even more preferably 5 parts by mass or less, and even more preferably 1.9 parts by mass or less.

As described above, the pressure-sensitive adhesive resin composition for forming pressure-sensitive adhesives is preferably a pressure-sensitive adhesive resin composition containing air bubbles. Although there is no particular limitation on the method of forming a composition containing air bubbles, for example, the following may be used.
First, the adhesive resin and solvent are used to form a colloid, suspension, sol, emulsion, etc., then salt and, if necessary, additives are added to prepare a stock solution, and nitrogen gas is supplied to the stock solution. By stirring while stirring, air bubbles can be contained in the stock solution, and a pressure-sensitive adhesive resin composition containing air bubbles can be prepared.

When supplying nitrogen gas, the density of the pressure-sensitive adhesive resin composition containing air bubbles can be adjusted by adjusting the amount of nitrogen gas supplied. By adjusting the density of the pressure-sensitive adhesive resin composition containing air bubbles, the pressure-sensitive adhesive layer formed using the composition easily satisfies the pore shape, density, etc. described above. It becomes easier to adjust B within the predetermined range, and as a result, reworkability is improved.

The density of the adhesive resin composition containing air bubbles is preferably 0.1 g/cm ³ or more, more preferably 0.2 g/cm ³ or more, still more preferably 0.3 g/cm ³ or more, and the upper limit is preferably It is 0.8 g/cm ³ or less, more preferably 0.7 g/cm ³ or less, still more preferably 0.6 g/cm ³ or less. When the density of the adhesive resin composition is within the above range, reworkability is improved as described above.

[Base material layer]
The substrate layer is a layer formed by attaching the pressure-sensitive adhesive sheet of the present disclosure to an adherend via the pressure-sensitive adhesive layer to form a surface layer of the adherend. Therefore, the substrate layer is preferably a layer having various properties desired for the adherend, and for example, it is preferable to use a decorative sheet as the substrate layer.
As the decorative sheet preferably used for the base material layer, commercially available decorative sheets can be employed without limitation. For example, a decorative sheet having a support layer 21, a decoration layer 22 (and a colored layer 22a and a pattern layer 22b) and a surface layer 23 as shown in FIG. 2 is typically preferred. In this case, the decorative sheet as the base material layer is provided so that the support layer and the adhesive layer face each other.
The support layer, decorative layer and surface layer are described below.

(support layer)
When the base layer has a support layer, the support layer is not only a layer that holds the decorative layer and the surface layer preferably possessed by the decorative sheet, but also a layer that is in contact with the adhesive layer. It is a layer that can greatly affect the adhesive strength A of. As the support layer, those commonly used as a base material for decorative sheets can be used without limitation. and the like.
Among the above-mentioned materials constituting the support layer, it is preferable to use resin and paper in consideration of the ease of production of the decorative sheet and the ease of acquisition. , it is more preferable to use a resin. Further, by using a base material composed of resin and paper as the support layer, the adhesive force A can be easily set to 17.0 N/25 mm or more.

The support layer may be a single layer or a composite layer comprising two or more layers made of the above materials. In the case where the support layer is a composite layer comprising two or more layers, it is preferable to comprise two or more layers of different materials so that the properties of the materials of each layer complement each other.

Examples of the support layer of the fibrous material include paper substrates such as kraft paper, titanium paper, backing paper for wallpaper, thin paper, fine paper, Japanese paper, and base paper for gypsum board. Examples of the paper base layer include inter-paper reinforced paper, resin-impregnated paper, etc., in which various resins such as acrylic resin, styrene-butadiene rubber, and melamine resin are added to improve interlaminar strength.

Examples of the non-woven fabric or woven fabric support layer include inorganic fibers made of inorganic materials such as glass, alumina, and carbon; organic fibers made of various synthetic resins such as polyester resin, acrylic resin, polyethylene, and polypropylene; silk; Base materials such as non-woven fabrics or woven fabrics composed of various fibers such as protein-based or cellulose-based natural fibers such as cotton and hemp, glass fibers and carbon fibers, and composites thereof.

Examples of the resin support layer include resin substrates composed of various resins such as synthetic resins and natural resins.
Examples of synthetic resins include polyolefin resins such as polypropylene, polyethylene, polymethylpentene, polyolefin thermoplastic elastomers, and ionomers; vinyl chloride resins such as polyvinyl chloride, polyvinylidene chloride, and vinyl chloride-vinyl acetate copolymer; polyethylene Polyester resins such as terephthalate (PET), polyethylene naphthalate (PEN), polyester thermoplastic elastomer; polymethyl (meth) acrylate, polybutyl (meth) acrylate, methyl (meth) acrylate-butyl (meth) acrylate copolymer acrylic resins; polyamide resins represented by nylon 6, nylon 66, etc.; cellulose resins such as cellulose triacetate, cellophane, and celluloid; Styrenic resin; thermoplastic resins such as polyvinyl alcohol, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polycarbonate resin, polyarylate resin, polyimide resin.
Natural resins include natural rubber, pine resin, amber, and the like.

Examples of the substrate layer of a wood-based material include wood substrates made of wood of various tree species such as cedar, cypress, pine, zelkova, oak, oak, walnut, lauan, teak, and rubber tree. The wood substrate may be in the form of a film or sheet called veneer, or in the form of a plate such as veneer, plywood, laminated wood, particle board, or fiberboard.

Metals include alloys containing aluminum such as aluminum and duralumin; alloys containing iron such as iron, carbon steel and stainless steel; alloys containing copper such as copper, brass and bronze; gold, silver, chromium, nickel, cobalt; Tin, titanium and the like can be mentioned. As the metal substrate layer composed of metal, those metals subjected to a treatment such as plating can also be used.
In addition, non-metallic inorganic materials include non-ceramic ceramic materials such as cement, ALC (lightweight cellular concrete), gypsum, calcium silicate, and wood cement; ceramic ceramic materials such as ceramics, earthenware, glass, and enamel; limestone. (including marble), natural stones such as granite and andesite.

The support layer may be colored or may not be colored (it may be transparent), and when colored, the mode of coloring is not particularly limited, and may be transparent and colored, Opaque coloring (concealing coloring) may be used, and these can be selected arbitrarily. Coloring is preferable in consideration of concealing the hue of the adherend, stabilizing the color tone of the decorative layer described later, and improving the design.

Examples of coloring agents include white pigments such as titanium white; inorganic pigments such as iron black, yellow lead, titanium yellow, red iron oxide, cadmium red, ultramarine blue, and cobalt blue; quinacridone red, isoindolinone yellow, phthalocyanine blue, and nickel. -Organic pigments or dyes such as azo complexes, azomethine azo black pigments, and perylene black pigments; metal pigments composed of flake-like foils such as aluminum and brass; from flake-like foils such as titanium dioxide-coated mica and basic lead carbonate coloring agents such as pearl luster (pearl) pigments. Considering the concealment of the hue of the adherend and the stability of the color tone of the decorative layer, it is preferable to use an inorganic pigment such as a white pigment.

When coloring a synthetic resin, any means such as adding (kneading or kneading) a coloring agent into the resin, or forming a coating film of a paint containing a resin and a coloring agent can be employed. In the case of coloring paper, non-woven fabric or woven fabric, it can be carried out by any means such as mixing with pulp or fiber material, coating film formation, or a combination thereof.
In the case of coloring of wood, it can be carried out by dyeing with a dye, by forming a coating film, or by a combination thereof. In the case of metal coloring, in addition to coating film formation, an electrolytic coloring method or the like can be employed in which a metal oxide film is formed on the surface using an anodic oxidation method. In the case of a non-metallic inorganic material, it can be carried out by forming a coating film, by adding it to the substrate, or by combining these methods.

Additives may be added to the support layer, if necessary.
Examples of additives, mainly in the case of resins, include weather resistance agents such as UV absorbers and light stabilizers; inorganic fillers such as calcium carbonate and clay; flame retardants such as magnesium hydroxide; Foaming agents, antioxidants, and the like are included. The amount of the additive compounded is not particularly limited as long as it does not impair the surface characteristics, processing characteristics, etc., and can be appropriately set according to the required characteristics.

From the viewpoint of improving the weather resistance of the laminate of the present disclosure, it is preferable to use weather resistance agents such as ultraviolet absorbers and light stabilizers among the above additives.
As the UV absorber, any UV absorber that is commonly used for decorative sheets can be used without particular limitation, such as benzotriazole UV absorbers, benzophenone UV absorbers, triazine UV absorbers, and hydroxyphenyltriazine UV absorbers. agents and the like.

As the light stabilizer, any light stabilizer commonly used for decorative sheets can be used without particular limitation, and examples thereof include hindered amine light stabilizers such as piperidinyl sebacate light stabilizers. Moreover, these ultraviolet absorbers and light stabilizers may have a reactive functional group having an ethylenic double bond such as a (meth)acryloyl group, vinyl group or allyl group in the molecule.
Weather resistance agents such as these ultraviolet absorbers and light stabilizers can be used alone or in combination.

The thickness of the support layer is not particularly limited, but in general, it may be about 10 μm or more and 10 cm or less, preferably 20 μm or more, in consideration of manufacturing processability, mechanical strength, ease of use and economy. , more preferably 40 μm or more, and the upper limit is preferably 300 μm or less, more preferably 200 μm or less, and still more preferably 100 μm or less.
When the base material layer is a paper base material, the basis weight is generally preferably 20 g/m ² or more and 150 g/m ^{2 or} less, more preferably 30 g/m ² or more and 100 g/m ² or less.

The support layer may be provided with a separate primer layer, which will be described later, in order to increase the adhesion with other layers such as the decorative layer and the surface layer that constitute the decorative sheet. A physical surface treatment such as a chemical method or a surface treatment such as a chemical surface treatment may be applied.

Examples of oxidation methods include corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, ozone-ultraviolet treatment, and the like. Examples of roughening methods include sandblasting and solvent treatment. These surface treatments are appropriately selected according to the type of substrate, but corona discharge treatment is generally preferred in consideration of the effect of the surface treatment, operability, and the like.

(decorative layer)
The decorative layer is a layer that imparts decoration to the decorative sheet used as the base material layer to improve designability, and is a layer that improves designability of the pressure-sensitive adhesive sheet of the present disclosure.
The decorative layer may be provided between the base material layer and the surface layer described later, and when the transparent resin layer described later is provided, it is provided between the base material layer and the transparent resin layer described later. (See Figure 2).

The decorative layer may be, for example, a colored layer covering the entire surface (so-called solid colored layer, "22a" in FIG. 2), or may be formed by printing various patterns using ink and a printing machine. It may be a pattern layer (“22b” in FIG. 2) to be printed. Alternatively, as shown in FIG. 2, a solid colored layer 22a and a pattern layer 22b may be combined.

The pattern (pattern) of the pattern layer is not particularly limited, and any desired pattern may be adopted. Examples include texture patterns on the surface of fabric, grain patterns on the surface of leather, geometric patterns, characters, figures, and combinations thereof.

The ink used for the decorative layer is a mixture of a binder resin and a coloring agent such as a pigment or dye, an extender pigment, a solvent, a stabilizer, a plasticizer, a catalyst, a curing agent, an ultraviolet absorber, a light stabilizer, etc. used.
The binder resin for the decorative layer is not particularly limited, and examples include urethane resins, acrylic polyol resins, acrylic resins, ester resins, amide resins, butyral resins, styrene resins, urethane-acrylic copolymers, and vinyl chloride-vinyl acetate copolymers. Resins such as coalesced resins, vinyl chloride-vinyl acetate-acrylic copolymer resins, chlorinated propylene resins, nitrocellulose resins, and cellulose acetate resins can be used. Moreover, various types of resins can be used, such as a one-pack curable resin and a two-pack curable resin with a curing agent such as an isocyanate compound.

As the colorant, a pigment having excellent hiding properties and weather resistance is preferred. Pigments similar to those exemplified as pigments that can be used in the substrate can be used.
The content of the colorant is preferably 5 parts by mass or more and 90 parts by mass or less, more preferably 15 parts by mass or more and 80 parts by mass or less, and 30 parts by mass or more and 70 parts by mass with respect to 100 parts by mass of the resin constituting the decorative layer. More preferred are:

The decorative layer may contain additives such as ultraviolet absorbers, weathering agents such as light stabilizers, and colorants.
The thickness of the decorative layer may be appropriately selected according to the desired pattern, and is preferably 0.5 μm or more and 20 μm or less, and 1 μm or more and 10 μm or less, in consideration of concealing the hue of the adherend and improving the design. is more preferable, and 2 μm or more and 5 μm or less is even more preferable.

(Surface layer)
The surface layer is a layer provided on the surface of the decorative sheet, that is, the surface of the pressure-sensitive adhesive sheet of the present disclosure, and is a layer provided as a layer having abrasion resistance, weather resistance, antifouling properties and other surface properties as desired. . Here, the surface of the pressure-sensitive adhesive sheet means the surface opposite to the surface of the base material layer on the adhesive layer side.
The surface layer is preferably a layer composed of a cured resin composition. This is because it is easy to develop the above surface characteristics.

Examples of the resin contained in the resin composition used for forming the surface layer include curable resins such as ionizing radiation curable resins and thermosetting resins.

An ionizing radiation-curable resin is a resin having an ionizing radiation-curable functional group, and the ionizing radiation-curable functional group is a group that is cross-linked and cured by irradiation with ionizing radiation. Preferred examples of such groups include functional groups having an ethylenic double bond, such as (meth)acryloyl groups, vinyl groups, and allyl groups. In addition, in this specification, a (meth)acryloyl group shows an acryloyl group or a methacryloyl group. Moreover, in this specification, (meth)acrylate indicates acrylate or methacrylate.
In addition, ionizing radiation means, among electromagnetic waves or charged particle beams, those having energy quanta capable of polymerizing and/or cross-linking molecules, and usually ultraviolet rays (UV) or electron beams (EB) are used, In addition, electromagnetic waves such as X-rays and γ-rays, and charged particle beams such as α-rays and ion beams are also included.

The ionizing radiation curable resin includes electron beam curable resins and ultraviolet curable resins, and either of them may be used.
Specifically, the ionizing radiation-curable resin can be appropriately selected and used from polymerizable monomers and polymerizable oligomers conventionally used as ionizing radiation-curable resins.

As the polymerizable monomer, a (meth)acrylate monomer having a radically polymerizable unsaturated group in the molecule is preferred.
The (meth)acrylate-based monomer is a monomer having at least a (meth)acryloyl group as an ionizing radiation-curable functional group, and is a monofunctional (meth)acrylate monomer having one ionizing radiation-curable resin, or a polyfunctional monomer having two or more ionizing radiation-curable resins. (Meth)acrylate monomers can be mentioned, and any can be used.

When using a polyfunctional monomer, the number of functional groups is preferably 2 or more, and the upper limit is preferably 8 or less, more preferably 6 or less, and still more preferably 4 or less.

Polymerizable oligomers include, for example, (meth)acrylate oligomers having two or more ionizing radiation-curable functional groups in the molecule and at least (meth)acryloyl groups as the functional groups. Preferred examples include urethane (meth)acrylate oligomers, epoxy (meth)acrylate oligomers, polyester (meth)acrylate oligomers, polyether (meth)acrylate oligomers, polycarbonate (meth)acrylate oligomers, and acrylic (meth)acrylate oligomers.

Furthermore, as polymerizable oligomers, there are also highly hydrophobic polybutadiene (meth)acrylate oligomers having (meth)acrylate groups in the side chains of polybutadiene oligomers, and silicone (meth)acrylate oligomers having polysiloxane bonds in the main chain. , aminoplast resins modified with aminoplast resins having many reactive groups in small molecules (meth)acrylate oligomers, novolac type epoxy resins, bisphenol type epoxy resins, aliphatic vinyl ethers, aromatic vinyl ethers, etc. There are oligomers having cationic polymerizable functional groups.

The number of functional groups of the polymerizable oligomer may be appropriately selected according to the desired surface properties, preferably 2 or more, more preferably 3 or more, and the upper limit is preferably 8 or less, more preferably 6 or less, and still more preferably. 4 or less. When the number of functional groups is within the above range, the various surface properties described above can be easily obtained.
For the same reason, the weight average molecular weight of these polymerizable oligomers is preferably 1,000 or more and 7,500 or less, more preferably 1,500 or more and 6,500 or less, and more preferably 1,750 or more and 5,000. The following are more preferable, and 1,900 or more and 4,000 or less are even more preferable. Here, the weight average molecular weight is the average molecular weight measured by GPC analysis and converted with standard polystyrene.

In the present disclosure, the polymerizable monomer can be used alone or in combination of multiple types, and the polymerizable oligomer can also be used alone or in combination of multiple types. Moreover, it is of course possible to use a combination of a polymerizable monomer and a polymerizable oligomer.

Thermosetting resins include acrylic resins, urethane resins, phenol resins, urea melamine resins, epoxy resins, unsaturated polyester resins, silicone resins, and the like. These can be used individually or in combination of multiple types.
Further, the thermosetting resin composition may be obtained by adding a curing agent such as an isocyanate curing agent or an epoxy curing agent to these resins. Among these, acrylic resins are preferable, and acrylic resins to which an isocyanate curing agent is added are more preferable.

The resin composition forming the surface layer may contain various additives according to desired surface properties as components other than the above resins. Preferable examples of such various additives include weather resistance agents, photopolymerization initiators, and photopolymerization accelerators.

As the weather resistant agent, for example, various weather resistant agents such as ultraviolet absorbers and light stabilizers are preferably used.
As the ultraviolet absorber and the light stabilizer, it is possible to appropriately select and use from those exemplified as the ultraviolet absorber and the light stabilizer that can be used in the support layer.

The content of the ultraviolet absorber with respect to 100 parts by mass of the resin forming the surface layer is preferably 0.1 parts by mass or more, more preferably 1.0 parts by mass or more, still more preferably 2.0 parts by mass or more, and even more preferably is 3.0 parts by mass or more, and the upper limit is preferably 10.0 parts by mass or less, more preferably 8.0 parts by mass or less, still more preferably 7.0 parts by mass or less, and even more preferably 6.0 parts by mass It is below. When the content of the ultraviolet absorber is within the above range, the effect of using the ultraviolet absorber efficiently can be obtained.
Moreover, the content of the light stabilizer is the same as that of the above ultraviolet absorber.

A photopolymerization initiator and a photopolymerization accelerator are preferably used when an ultraviolet curable resin is used as the curable resin.
Examples of the photopolymerization initiator include one or more selected from acetophenone, benzophenone, α-hydroxyalkylphenone, Michler's ketone, benzoin, benzyldimethylketal, benzoylbenzoate, α-acyloxime ester, thioxanthones, and the like.
In addition, the photopolymerization accelerator can reduce polymerization inhibition by air during curing and increase the curing speed. One or more selected types can be mentioned.

The content of the photopolymerization initiator with respect to 100 parts by mass of the resin forming the surface layer is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and the upper limit is preferably 5 parts by mass or less. Preferably, it is 1.5 parts by mass or less. When the content of the photopolymerization initiator is within the above range, the effect of efficiently using the photopolymerization initiator can be obtained.
Moreover, the content of the photopolymerization accelerator is the same as that of the photopolymerization initiator.

(Other layers that the decorative sheet may have)
The decorative sheet preferably used as the base layer of the pressure-sensitive adhesive sheet of the present disclosure preferably has the layer structure shown in FIG. This is the simplest and preferred layer structure.
In addition, the decorative sheet used as the base material layer may optionally have other layers such as a primer layer, a transparent resin layer and an adhesive layer. A representative layer structure of the decorative sheet having these layers is, as shown in FIG. A layer configuration having layers 23 in sequence can be mentioned.

(primer layer)
As described above, the primer layer is a layer that is provided to improve the interlayer adhesion between the layers that make up the decorative sheet.
For example, when it has a support layer and a surface layer, between the support layer and the surface layer, and when it has a transparent resin layer as shown in FIG. 3, between the transparent resin layer and the surface layer. A primer layer can be provided in between to improve interlayer adhesion.

The primer layer is mainly composed of a binder resin, and may contain additives such as ultraviolet absorbers and light stabilizers, if necessary.

Binder resins include urethane resins, acrylic polyol resins, acrylic resins, ester resins, amide resins, butyral resins, styrene resins, urethane-acrylic copolymers, and polycarbonate-based urethane-acrylic copolymers (carbonate bonds in the polymer main chain). urethane-acrylic copolymer derived from a polymer (polycarbonate polyol) having two or more hydroxyl groups at the end and side chain), vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-acrylic copolymer Resins such as coalescent resins, chlorinated propylene resins, nitrocellulose resins (nitrocellulose), and cellulose acetate resins are preferred, and these can be used alone or in combination.

The binder resin may be a resin obtained by adding a curing agent such as an isocyanate-based curing agent or an epoxy-based curing agent to the above-mentioned resin and curing by cross-linking. For example, a resin obtained by crosslinking and curing a polyol resin such as an acrylic polyol resin with an isocyanate curing agent is preferable, and a resin obtained by crosslinking and curing an acrylic polyol resin with an isocyanate curing agent is more preferable.

The thickness of the primer layer is preferably 0.5 µm or more, more preferably 1 µm or more, still more preferably 2 µm or more, and the upper limit is preferably 10 µm or less, more preferably 8 µm or less, and still more preferably 6 µm or less.

(Transparent resin layer)
The transparent resin layer is a layer that is preferably provided in order to increase the strength of the decorative sheet and to protect the decorative layer when the decorative sheet is provided. In particular, when the pressure-sensitive adhesive sheet of the present disclosure is used for building interior members such as flooring materials, and frequently used fitting members such as window frames, doors, door frames, and handrails, the transparent resin layer is provided. is valid.
The transparent resin layer may be provided, for example, between the support layer and the surface layer, or, if there is a decoration layer, between the decoration layer and the surface layer to protect the decoration layer (see FIG. 3).

Examples of resins constituting the transparent resin layer include polyolefin resins, polyester resins, polycarbonate resins, acrylonitrile-butadiene-styrene resins (hereinafter also referred to as "ABS resins"), acrylic resins, vinyl chloride resins, and the like. Among these, polyolefin-based resins and vinyl chloride resins are preferred in consideration of workability. Also, two or more of these various resins may be laminated or mixed for use.

The transparent resin layer may be transparent to the extent that the base material side is visible from the transparent resin layer, and if it has a decorative layer, it may be transparent to the extent that the decorative layer can be visually recognized. , colored transparent and translucent. That is, in the present specification, "transparency" means colorless transparency, as well as colored transparency and semi-transparency.

The transparent resin layer may contain additives such as UV absorbers, light stabilizers and other weather resistance agents, and colorants and the like. Additives such as these weather resistance agents and colorants may be appropriately selected from those described above and used.
The thickness of the transparent resin layer is preferably 20 μm or more and 150 μm or less, more preferably 40 μm or more and 120 μm or less, and even more preferably 60 μm or more and 100 μm or less, in consideration of protection of the decorative layer, workability, and the like.

(adhesion layer)
When the decorative sheet has a support layer and a transparent resin layer, the adhesive layer is preferably provided between the support layer and the transparent resin layer in order to improve adhesion between these layers.
When a decorative layer is further provided between the support layer and the transparent resin layer, the positional relationship between the adhesive layer and the decorative layer is not particularly limited. and a transparent resin layer may be provided in this order (see FIG. 3), or an adhesive layer, a decoration layer and a transparent resin layer may be provided in this order from the side closer to the support layer.

The adhesive layer can be composed of, for example, an adhesive such as a urethane-based adhesive, an acrylic adhesive, an epoxy-based adhesive, or a rubber-based adhesive. Among these adhesives, urethane-based adhesives are preferable in terms of adhesive strength.
Urethane-based adhesives include, for example, adhesives using two-liquid curing urethane resins containing various polyol compounds such as polyether polyols, polyester polyols and acrylic polyols, and curing agents such as isocyanate compounds.

The thickness of the adhesive layer is preferably 0.1 μm or more and 30 μm or less, more preferably 1 μm or more and 15 μm or less, and even more preferably 2 μm or more and 10 μm or less, from the viewpoint of efficiently obtaining desired adhesive strength.

[Method for manufacturing decorative sheet]
The decorative sheet preferably used as the base layer in the pressure-sensitive adhesive sheet of the present disclosure, for example, when the decorative sheet comprises a support layer and a surface layer, is prepared by the following method;
A surface coating layer forming step in which a coating layer is formed by coating a resin composition for forming a surface layer on one main surface of a base material, and the surface coating layer is cured by irradiation treatment with ionizing radiation such as ultraviolet rays. to form a surface layer, a surface layer forming step;
It is preferable to manufacture via Moreover, when the resin composition for forming the surface layer contains a solvent, the solvent drying step may be performed after the coating layer forming step.

(Surface coating layer forming step)
In the surface coating layer forming step, the resin composition for forming the surface layer is applied by a known method such as a gravure printing method, a bar coating method, a roll coating method, a reverse roll coating method, a comma coating method, etc., and uncured. A coating layer composed of the resin composition of (1) is formed.

The resin composition for forming the surface layer used in the step of forming the surface coating layer is the resin composition described in the description of the surface layer, and preferably contains an ionizing radiation-curable resin as a resin and a photopolymerization initiator. , and other additives such as weathering agents.
In the surface coating layer forming step, the thickness of the surface coating layer formed by applying the resin composition for forming the surface layer is the same as the thickness described above as the thickness of the surface layer.

(Surface layer forming step)
In the surface layer forming step, the surface coating layer formed from the uncured resin composition formed in the surface coating layer forming step is cured by irradiation with ionizing radiation such as electron beams and ultraviolet rays to form a surface layer. Form.

When an electron beam is used as the ionizing radiation, the acceleration voltage can be appropriately selected according to the resin used and the thickness of the layer, but it is usually preferable to cure the uncured resin layer at an acceleration voltage of about 70 to 300 kV. The irradiation dose is preferably an amount that saturates the crosslink density of the ionizing radiation curable resin, and is usually selected in the range of 5 to 300 kGy (0.5 to 30 Mrad), preferably 10 to 50 kGy (1 to 5 Mrad).
The electron beam source is not particularly limited, and various electron beam accelerators such as Cockroft-Walton type, Vandegraft type, resonance transformer type, insulating core transformer type, linear type, dynamitron type, and high frequency type are used. be able to.
When ultraviolet rays are used as the ionizing radiation, radiation containing ultraviolet rays having a wavelength of 190 to 380 nm is emitted. There are no particular restrictions on the ultraviolet light source, and for example, high-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, carbon arc lamps and the like are used.

(Formation of other layers)
The manufacturing method in the case where the decorative sheet used in the pressure-sensitive adhesive sheet of the present disclosure has a layer structure including a support layer and a surface layer has been described above. That is, it can have layers such as a primer layer, a transparent resin layer, a decorative layer, and an adhesive layer.

For example, the decorative layer, the adhesive layer, and the primer layer can be formed by applying a coating liquid containing the composition for forming each layer by the known method described above, and drying and curing as necessary.
Moreover, when forming a transparent resin layer, a resin film forming the transparent resin layer can be formed by dry lamination or the like.

[Peelable sheet layer]
The pressure-sensitive adhesive sheet of the present disclosure has a substrate layer, an adhesive layer, and a releasable sheet layer in this order. It has a peelable sheet layer on the side surface. The peelable sheet layer is provided facing the adhesive layer to protect the adhesive layer and prevent blocking by the adhesive layer between the adhesive sheets when the adhesive sheets of the present disclosure are stored in a rolled form or stacked. can be suppressed.
Moreover, the peelable sheet layer is preferably provided so as to be in contact with the adhesive layer in order to protect the adhesive layer.

In the pressure-sensitive adhesive sheet of the present disclosure, the pressure-sensitive adhesive layer and the substrate layer are peeled off from the peelable sheet layer, and the pressure-sensitive adhesive layer and the adherend are attached so that the pressure-sensitive adhesive layer and the adherend face each other. Used. That is, the peelable sheet layer is peeled off and removed from the surface of the adhesive layer when the adhesive sheet is used, such as being attached to an adherend or the like.

The peelable sheet layer is not particularly limited as long as it is a sheet layer that can be peeled off from the adhesive layer, and various forms such as a release film, separate paper, separate film, separator paper, release film, release paper, etc. Can be used as appropriate. As the peelable sheet layer, for example, woodfree paper, coated paper, impregnated paper, plastic film or the like having a peeling layer formed on one side or both sides thereof can be used.

The release layer is not particularly limited as long as it is a layer formed of a material having releasability (also referred to as “releasability”). Examples of materials having releasability include silicone resins, organic resin-modified silicone resins, fluorine resins, aminoalkyd resins, melamine resins, acrylic resins, polyester resins, and the like. These resins may be emulsion type, solvent type or non-solvent type.

When a release film having a release layer is used, for example, silicone release type PET (polyethylene terephthalate) film, untreated PET film, PP (polypropylene) film, silicone release type paper, etc. can be used. .
When the release sheet layer has a release layer, the release sheet layer is preferably provided so that the adhesive layer and the release layer face each other, more preferably so that the adhesive layer and the release layer are in contact with each other. .

The thickness of the peelable sheet layer is preferably 10 µm or more, more preferably 20 µm or more, still more preferably 30 µm or more, and the upper limit is preferably 200 µm or less, more preferably 150 µm or less, and still more preferably 125 µm or less. When the thickness of the peelable sheet layer is within the above range, the peelable sheet layer can be provided with stiffness, so that it can be easily peeled off and the workability at the time of application is improved.

[Method for producing adhesive sheet]
The method for producing the pressure-sensitive adhesive sheet of the present disclosure comprises:
an adhesive coating layer forming step of applying an adhesive layer-forming resin composition onto the releasable surface of the release sheet layer to form an adhesive coating layer of the adhesive layer-forming resin composition;
An adhesive layer forming step of drying the adhesive coating layer to form an adhesive layer that is porous;
including,
Adhesion A between the base material layer and the adhesive layer measured by a predetermined measuring method is 17.0 N/25 mm or more,
The adhesive strength B between the adhesive layer and the SUS304 steel plate measured by a predetermined measuring method is 1.0 N / 25 mm or more and 10.0 N / 25 mm or less.
A method for producing an adhesive sheet. The pressure-sensitive adhesive sheet of the present disclosure can be easily produced by the method for manufacturing the pressure-sensitive adhesive sheet of the present disclosure.

(Adhesive coating layer forming step)
The adhesive layer-forming resin composition can be applied by known methods such as gravure printing, bar coating, roll coating, reverse roll coating, and comma coating.
The adhesive layer-forming resin composition used in the adhesive coating layer forming step is as described above, and is preferably an adhesive resin composition containing air bubbles. The method for incorporating air bubbles into the adhesive resin composition is also as described above.

The coating amount may be set to the thickness of the adhesive layer described above, preferably 10 g/m ² or more, more preferably 15 g/m ² or more, still more preferably 18 g/m ² or more, and even more preferably 20 g /m ² or more, and the upper limit is preferably 100 g/m ² or less, more preferably 85 g/m ² or less, still more preferably 75 g/m ² or less, and even more preferably 70 g/m ² or less.

(Adhesive layer forming step)
The adhesive layer forming step is a step of drying the adhesive coating layer formed in the adhesive coating layer forming step to form an adhesive layer.
The method of drying the adhesive coating layer includes, for example, a method of drying by heating, a method of drying while blowing air, and the like, and drying can be performed using a dryer capable of such drying. The drying temperature may vary depending on the type of solvent used in the adhesive resin composition, so it cannot be said unconditionally. , preferably 80° C. or higher, more preferably 90° C. or higher, and the upper limit is preferably 130° C. or lower, more preferably 120° C. or lower.

In addition, the drying time may vary depending on the type of solvent used in the adhesive resin composition, the conditions of the drying temperature, etc., so it cannot be said unconditionally. Considering that it is preferably 30 seconds or more, more preferably 45 seconds or more, and still more preferably 1 minute or more, the upper limit is preferably 5 minutes or less, more preferably 3 minutes and 30 seconds or less, and still more preferably 2 minutes. 30 seconds or less.

By drying the adhesive resin composition containing air bubbles in this way, the air bubbles burst in a state in which the adhesive resin is appropriately dried, so that part of the shape of the air bubbles tends to remain. Become. As a result, concave shapes can be formed more easily and uniformly on the surface of the pressure-sensitive adhesive resin composition containing air bubbles. As a result, the adhesive layer becomes a porous layer, the adhesive strengths A and B are within a predetermined range, and excellent reworkability is obtained.

(Adhesion process)
The adhesion step is a step of adhering the substrate layer and the adhesive layer formed by the adhesive layer forming step.
When a decorative sheet is employed as the base material layer, a commercially available decorative sheet may be used, or a decorative sheet may be used after being produced by the production method described above.

Adhesion between the base material layer and the adhesive layer is achieved, for example, by placing a decorative sheet preferably used as the base material layer and a peelable sheet layer provided with an adhesive layer by the adhesive layer forming step, and then separating the decorative sheet and the adhesive layer. It is sufficient to stick them so that they face each other. The bonding can be performed by a known lamination method.

At this time, the lamination pressure in adhesion between the base material layer and the adhesive layer is preferably 0.30 MPa or more. By setting the lamination pressure within the above range for adhesion, the adhesive strength A between the substrate layer and the adhesive layer can be easily adjusted to the above range, that is, 17.0 N/25 mm or more. From the same point of view, the lamination pressure is more preferably 0.32 MPa or higher, still more preferably 0.35 MPa or higher. As for the upper limit, there is no particular restriction on the adhesion strength A within the above range, but for the convenience of manufacturing, it is usually 0.65 MPa or less, preferably 0.60 MPa or less.

[Method for measuring adhesion]
The method for measuring the adhesive strength A of the present disclosure, that is, the method for measuring the adhesive strength A between the base layer and the adhesive layer of the adhesive sheet,
JIS Z0237: 2009 (Testing methods for adhesive tapes and adhesive sheets), Method 3 (180° peeling adhesive strength of double-sided tape), SUS304 steel plate and the adhesive sheet (width: 25 mm, length: 100 mm) The adhesive layer is attached via a double-sided adhesive tape, and 1 hour after attachment, a peel strength measuring instrument is used to peel off the base layer and the adhesive layer at 180 ° ( Peeling speed: 300 mm / min) and the adhesion strength measured is the adhesion strength A,
This is the measurement method.

The method for measuring the adhesive strength A between the base layer and the adhesive layer of the adhesive sheet of the present disclosure is applied to the measurement of the adhesive strength between the base layer and the adhesive layer in the adhesive sheet having at least the base layer and the adhesive layer. can. Therefore, the method for measuring the adhesive strength A of the pressure-sensitive adhesive sheet of the present disclosure is not limited to the pressure-sensitive adhesive sheet of the present disclosure, and can be widely applied to other pressure-sensitive adhesive sheets having at least a base material layer and an adhesive layer.

The measurement of the adhesive strength A of the present disclosure is basically based on JIS Z0237: 2009 (Testing methods for adhesive tapes and adhesive sheets) Method 3 (180 ° peeling adhesive strength of double-sided tape). In particular, the use of a double-sided adhesive tape is characterized in that the adhesion between the substrate layer and the adhesive layer can be measured. As a result, it is possible to reliably separate from the interface between the substrate layer and the adhesive layer, and it is possible to reliably measure the adhesion between these layers.

As the double-sided adhesive tape used in the method for measuring the adhesive strength A of the present disclosure, as described above, the adhesive strength between the double-sided adhesive tape and the SUS304 steel plate is the adhesive strength A between the base layer and the adhesive layer, and the double-sided adhesive Any material stronger than the adhesive force between the tape and the adhesive layer can be used without any particular limitation, and may be appropriately selected from commercially available products.

In addition, the method for measuring the adhesive strength B of the present disclosure, that is, the method for measuring the adhesive strength B between the adhesive layer of the adhesive sheet and the SUS304 steel plate,
In accordance with JIS Z0237: 2009 (testing methods for adhesive tapes and adhesive sheets), method 1 (180° peeling adhesive strength to test plate), the adhesive sheet (width: 25 mm, length: 100 mm) was applied to a SUS304 steel plate. is attached, immediately after attachment, and 24 hours after attachment, the adhesive sheet is peeled off 180 ° using a peel strength measuring instrument (peeling speed: 300 mm / min) and measured. Let the adhesion force be the adhesion force B,
This is the measurement method.

The method of measuring the adhesion B between the adhesive layer of the adhesive sheet and the SUS304 steel plate of the present disclosure is the adhesion (initial adhesion B ₁ ) measured immediately after sticking, and measured 24 hours after sticking. This is a method for measuring both the adhesion strength (normal adhesion strength B ₂ ). That is, the adhesion B measured by the measuring method of the present disclosure is an adhesion including both the initial adhesion _B1 and the normal adhesion _B2 .
In addition, since the adhesive strength of the adhesive sheet peeled immediately after application cannot be measured 24 hours after application, it is preferable to prepare a plurality of samples of the adhesive sheet to be used for the measurement of the adhesive strength.

The method for measuring the adhesion strength B between the adhesive layer of the adhesive sheet and the SUS304 steel plate of the present disclosure is as follows. It can be applied to measure the adhesion force with. Therefore, the method for measuring the adhesive strength B of the pressure-sensitive adhesive sheet of the present disclosure is not limited to the pressure-sensitive adhesive sheet of the present disclosure, and can be widely applied to other pressure-sensitive adhesive sheets having at least an adhesive layer.

In the method for measuring the adhesion force B of the present disclosure, the SUS304 steel plate is assumed as the adherend as described above. It is possible to easily measure the adhesion force between the pressure-sensitive adhesive sheet and the adherend. That is, the method for measuring the adhesive strength B of the present disclosure is not limited to SUS304 steel plate, but is a measurement method that can be widely applied to any adherend to which the pressure-sensitive adhesive sheet can adhere.

[Decorative parts]
The pressure-sensitive adhesive sheet of the present disclosure can be laminated with an adherend and used as a so-called decorative member that constitutes the surface of buildings, various types of furniture, vehicles, home electric appliances, and the like.
The decorative member includes the pressure-sensitive adhesive sheet of the present disclosure and an adherend. Specifically, the surface of the adherend requiring decoration or the like faces the adhesive layer of the pressure-sensitive adhesive sheet of the present disclosure. It is laminated.

(Substrate)
Examples of the adherend include a member made of a material appropriately selected from the materials exemplified as those that can be employed as the substrate layer.
The material to be adhered may be appropriately selected from the above according to the purpose of use. Interior members of buildings such as walls, ceilings and floors; exterior members such as outer walls, roofs, soffits, fences and gates; Frames, doors, handrails, baseboards, rims, malls, and other fittings or fixtures; when used, wooden members made of wood-based materials, metal members made of metal, and resin. It is preferably made of at least one member selected from resin members, and when it is used as exterior members such as entrance doors, window frames, doors and other fittings, it is made of at least one member selected from metal members and resin members. things are preferred.

The thickness of the adherend may be appropriately selected according to the application and material, and is preferably 0.1 mm or more, more preferably 0.3 mm or more, still more preferably 0.5 mm or more, and the upper limit is preferably 100 mm. Below, more preferably 5 mm or less, still more preferably 3 mm or less.

(adhesive layer)
The pressure-sensitive adhesive sheet of the present disclosure and the adherend are preferably attached via an adhesive layer in order to obtain excellent adhesiveness.
The adhesive used for the adhesive layer is not particularly limited, and known adhesives can be used, and may be appropriately selected according to the application. For example, adhesives such as moisture-curable adhesives, anaerobic-curable adhesives, dry-curable adhesives, UV-curable adhesives, heat-sensitive adhesives (e.g., hot-melt adhesives), and pressure-sensitive adhesives are preferred. be done.

Examples of resins used for these adhesives include acrylic resins, urethane resins, vinyl chloride resins, vinyl acetate resins, vinyl chloride-vinyl acetate copolymers, styrene-acrylic copolymers, polyester resins, amide resins, Examples include cyanoacrylate resins and epoxy resins, and these can be used alone or in combination. In addition, a two-liquid curing type urethane-based adhesive or an ester-based adhesive using an isocyanate compound or the like as a curing agent can also be applied.
A pressure-sensitive adhesive can also be used for the adhesive layer. As the adhesive, various adhesives such as acrylic, urethane, silicone, and rubber can be appropriately selected and used.

Although the thickness of the adhesive layer is not particularly limited, it is preferably 1 μm or more, more preferably 5 μm or more, and still more preferably 10 μm or more, and the upper limit is preferably 100 μm or less, more preferably 50 μm or less, and further preferably 30 μm or less. is. When the thickness of the adhesive layer is within the above range, excellent adhesiveness can be efficiently obtained.

(Manufacturing method of decorative member)
The decorative member can be manufactured through a step of laminating the pressure-sensitive adhesive sheet of the present disclosure and an adherend.
This step is a step of laminating the pressure-sensitive adhesive sheet of the present disclosure and an adherend, and the surface of the adherend requiring decoration or the like faces the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet. As a method for laminating the adhesive sheet and the adherend, for example, there is a lamination method in which the laminated body is laminated on the plate-like adherend by pressing with a pressure roller via an adhesive layer.

When a hot-melt adhesive (heat-sensitive adhesive) is used as the adhesive, the heating temperature is preferably 160° C. or higher and 200° C. or lower, although it depends on the type of resin that constitutes the adhesive. °C or higher and 130 °C or lower.

[Use]
The decorative member using the pressure-sensitive adhesive sheet of the present disclosure can be arbitrarily cut, and arbitrarily decorated such as grooving and chamfering can be applied to the surface and the butt end using a cutting machine such as a router and a cutter. And various uses, for example, interior members of buildings such as walls, ceilings, and floors; exterior members such as outer walls, eaves, roofs, fences, fences, etc.; Fittings or fixtures such as rims and malls; General furniture such as wardrobes, shelves, and desks; Kitchen furniture such as dining tables and sinks; It is suitably used as various members such as decorative surface panels for cabinets of home appliances and OA equipment; interior and exterior members for vehicles; and the like. When the laminate of the present disclosure is in the form of a sheet, it is suitably used as a decorative sheet for the various members described above.

Furthermore, in addition to the various members described above, the pressure-sensitive adhesive sheet of the present disclosure can be used alone, or in the form of being laminated or combined with other materials, such as packaging materials, anti-glare films for displays, whiteboards or blackboards, credit cards. , cash cards, telephone cards, various certificates, etc., keyboards of various keyboards, windows, doors, transparent plates such as partitions (window glass, etc.), artificial leather, etc.

EXAMPLES Next, the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited by these examples.

(Measurement of adhesion strength A and B)
Using the pressure-sensitive adhesive sheets produced in Examples and Comparative Examples, the adhesion strengths A and B were measured by the above measuring method.
As for the adhesion strength B, the initial adhesion strength _B1 immediately after the adhesive sheet was adhered to the SUS304 steel plate, and the normal adhesion strength _B2 after 24 hours from adhesion were measured.

(Evaluation of adhesive residue (“reworkability”))
A sample of the pressure-sensitive adhesive sheet (length: 150 mm, width: 2.5 mm) prepared in Examples and Comparative Examples was attached to a stainless steel plate ( SUS304, No. 2B, thickness 2 mm), and left under conditions of 40° C. for 1 week. After standing under the above conditions, the pressure-sensitive adhesive sheet sample was peeled off, and reworkability was evaluated according to the following evaluation criteria when affixed again to a vinyl chloride decorative sheet of a newly prepared stainless steel plate.
A: There was no adhesive residue on the vinyl chloride decorative sheet at the time of peeling, and it was possible to re-stick it onto a newly prepared vinyl chloride decorative sheet made of a stainless steel plate.
C: At the time of peeling, adhesive remained on the vinyl chloride decorative sheet, the pressure-sensitive adhesive sheet itself was torn, and the peeling was not clean. Alternatively, although it could be peeled cleanly, it could not be pasted again on a vinyl chloride decorative sheet of a newly prepared stainless steel plate.

(Preparation of adhesive resin composition containing air bubbles)
Acrylic emulsion containing acrylic polymer (acrylic polymer: "DICNAL MFP-20 (trade name)" (manufactured by DIC), weight average molecular weight: 270,000, acrylic polymer concentration: 50%, solvent: water), acrylic polymer Ammonium sulfate as a salt is put into a stirrer at a ratio of 1/15 to the mass (6.7 parts by mass with respect to 100 parts by mass of the acrylic polymer), and the acrylic emulsion is stirred while nitrogen gas is mixed. Then, air bubbles were contained in the acrylic emulsion to prepare a pressure-sensitive adhesive resin composition containing air bubbles. The resulting adhesive resin composition containing air bubbles had a density of 0.4 g/cm ³ .

[Example 1]
A polyethylene terephthalate film (trade name “SP-PET PET-O3-BU”, manufactured by Mitsui Chemicals Tohcello, Inc., thickness: 40 μm) whose surface has been subjected to release treatment is used as a release sheet layer, and on the release-treated surface, The adhesive resin composition containing air bubbles prepared as described above was applied so that the coating amount after drying was 30 g/m ² , and dried in a drying oven at 100°C for 2 minutes to form an adhesive layer. formed. The formed adhesive layer had a density of 0.4 g/cm ³ . Next, as a base layer, a decorative sheet (“WS-5022E (model number)”, manufactured by Dai Nippon Printing Co., Ltd., having a support layer, a decorative layer, an adhesive layer, a transparent resin layer, a primer layer and a surface layer in this order, the surface The layer is a decorative sheet which is a cured product of an ionizing radiation-curable resin.) and the adhesive layer were laminated at a lamination pressure of 0.35 MPa so as to face each other to obtain an adhesive sheet.
Adhesion strengths A and B of the resulting pressure-sensitive adhesive sheet were measured by the method described above, and adhesive residue was evaluated. Table 1 shows the measurement results and evaluation results.

[Examples 2 to 5, and Comparative Examples 1 and 2]
PSA sheets of Examples 2 to 5 and Comparative Examples 1 and 2 were obtained in the same manner as in Example 1, except that the lamination pressure in Example 1 was changed to the pressure shown in Table 1.
Adhesion strengths A and B of the resulting pressure-sensitive adhesive sheet were measured by the method described above, and adhesive residue was evaluated. Table 1 shows the measurement results and evaluation results.

According to Examples 1 to 5, the adhesive sheets of the present disclosure have adhesive strengths A and B of 17.0 N/25 mm or more and 1.0 N/25 mm or more and 10.0 N/25 mm or less, respectively, so that there is no adhesive residue. It was confirmed to be excellent in evaluation and to have excellent reworkability.
On the other hand, the pressure-sensitive adhesive sheets of Comparative Examples 1 and 2 had low adhesive strength A, that is, the adhesive strength between the base layer and the pressure-sensitive adhesive layer.

(Reference example)
Using the pressure-sensitive adhesive sheet obtained in Example 1, in the method for measuring the adhesion strength B, the SUS304 steel plate was replaced with a plate of various materials shown in Table 2, and the adhesion of the pressure-sensitive adhesive sheet and the plate of the various materials was measured. force was measured. Table 2 shows the measurement results. In addition, the evaluation of adhesive residue was also performed based on the method for evaluating adhesive residue described above. The evaluation results are shown in Table 2.

註）
各種材料の板１：アルミニウム板（Ａ５０５２）
各種材料の板２：アクリル板（品名：アクリライト、三菱ケミカル社製）
各種材料の板３：ＡＢＳ板
各種材料の板４：ウレタン塗装板（化粧シート床材、大建工業社製）
各種材料の板５：メラミン焼付塗装板（品番：５８１８１、日本緑十字社製）
各種材料の板６：塩ビ樹脂化粧シート（型番：ダイノック、３Ｍ社製）

Note)
Plate 1 of various materials: aluminum plate (A5052)
Plate 2 of various materials: Acrylic plate (Product name: Acrylite, manufactured by Mitsubishi Chemical Corporation)
Board of various materials 3: ABS board Board of various materials 4: Urethane coated board (decorative sheet floor material, manufactured by Daiken Kogyo Co., Ltd.)
Plate 5 of various materials: Melamine baked plate (Product number: 58181, manufactured by Japanese Green Cross Co., Ltd.)
Plate 6 of various materials: PVC resin decorative sheet (model number: Dainok, manufactured by 3M)

In the reference example, the SUS304 steel plate used in the method for measuring the adhesion force B was changed to plates of the various materials described above to examine the effect on the adhesive residue when the adhesion force B was changed in a simulated manner. is. According to this, it can be seen that when the adhesive sheet of the present disclosure satisfies the adhesion strength B, the evaluation of adhesive residue is excellent, and excellent reworkability can be obtained. On the other hand, from the result of the plate material 6, it can be seen that when the adhesive strength B does not have the adhesive strength that the adhesive sheet of the present disclosure should have, the evaluation of adhesive residue is poor and excellent reworkability cannot be obtained.
From the above results, the pressure-sensitive adhesive sheet of the present disclosure is excellent in evaluation of adhesive residue due to adhesion strengths A and B of 17.0 N/25 mm or more and 1.0 N/25 mm or more and 10.0 N/25 mm or less. It can be seen that it has excellent reworkability.

The pressure-sensitive adhesive sheet of the present disclosure can be used in various applications, for example, interior members of buildings such as walls, ceilings and floors; exterior members such as outer walls, eaves, roofs, fences and fences; window frames, doors and door frames; , handrails, baseboards, rims, malls, and other fittings or fixtures; general furniture such as chests of drawers, shelves, desks; kitchen furniture such as dining tables and sinks; Various furniture and members used in; surface decorative boards such as cabinets for home appliances and OA equipment; interior and exterior members for vehicles;
Furthermore, in addition to the above-mentioned various members, the laminate can be used alone or in a form laminated or combined with other materials, such as packaging materials, antiglare films for displays, whiteboards or blackboards, credit cards, cash cards. , telephone cards, various cards such as various certificates, keyboards of various keyboards, windows, doors, transparent plates such as partitions (window glass, etc.), artificial leather, and the like.

REFERENCE SIGNS LIST 1 adhesive sheet 2 substrate layer 21 support layer 22 decorative layer 22a colored layer 22b pattern layer 23 surface layer 24 adhesive layer 25 transparent resin layer 26 primer layer 3 adhesive layer 31 pores (spherical pores)
32 pore (concave shape)
4 Peelable sheet layer

Claims (11)

Having a substrate layer, an adhesive layer, and a peelable sheet layer in this order,
The adhesive layer is porous,
The adhesive strength A between the base material layer and the adhesive layer measured by the following measuring method is 17.0 N/25 mm or more,
The adhesive strength B between the adhesive layer and the SUS304 steel plate measured by the following measuring method is 1.0 N/25 mm or more and 10.0 N/25 mm or less.
adhesive sheet.
(Method for measuring adhesion A)
JIS Z0237: 2009 (Testing methods for adhesive tapes and adhesive sheets), Method 3 (180° peeling adhesive strength of double-sided tape), SUS304 steel plate and the adhesive sheet (width: 25 mm, length: 100 mm) The adhesive layer is attached via a double-sided adhesive tape, and 1 hour after attachment, a peel strength measuring instrument is used to peel off the base layer and the adhesive layer at 180 ° ( Peeling speed: 300 mm/min.
(Method for measuring adhesion B)
In accordance with JIS Z0237: 2009 (testing methods for adhesive tapes and adhesive sheets), method 1 (180° peeling adhesive strength to test plate), the adhesive sheet (width: 25 mm, length: 100 mm) was applied to a SUS304 steel plate. is attached, immediately after attachment, and 24 hours after attachment, the adhesive sheet is peeled off 180 ° using a peel strength measuring instrument (peeling speed: 300 mm / min) and measured. Adhesion strength is defined as adhesion strength B. The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive layer becomes a porous layer due to air bubbles contained in the pressure-sensitive adhesive resin composition forming the pressure-sensitive adhesive layer. The adhesive sheet according to claim 1 or 2, wherein the adhesive layer has a thickness of 10 µm or more and 100 µm or less. The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the adhesive strength A is 17.0 N/25 mm or more and 35.0 N/25 mm or less. 5. The base material layer is a decorative sheet having a support layer, a decorative layer and a surface layer, and the decorative sheet is provided so that the support layer and the adhesive layer face each other. The adhesive sheet described in . an adhesive coating layer forming step of applying an adhesive layer-forming resin composition onto the releasable surface of the release sheet layer to form an adhesive coating layer of the adhesive layer-forming resin composition;
An adhesive layer forming step of drying the adhesive coating layer to form a porous adhesive layer, and a bonding step of bonding the base layer and the adhesive layer,
The adhesive strength A between the base material layer and the adhesive layer measured by the following measuring method is 17.0 N/25 mm or more,
The adhesive strength B between the adhesive layer and the SUS304 steel plate measured by the following measuring method is 1.0 N/25 mm or more and 10.0 N/25 mm or less.
A method for manufacturing an adhesive sheet.
(Method for measuring adhesion A)
JIS Z0237: 2009 (Testing methods for adhesive tapes and adhesive sheets), Method 3 (180° peeling adhesive strength of double-sided tape), SUS304 steel plate and the adhesive sheet (width: 25 mm, length: 100 mm) The adhesive layer is attached via a double-sided adhesive tape, and 1 hour after attachment, a peel strength measuring instrument is used to peel off the base layer and the adhesive layer at 180 ° ( Peeling speed: 300 mm/min.
(Method for measuring adhesion B)
In accordance with JIS Z0237: 2009 (testing methods for adhesive tapes and adhesive sheets), method 1 (180° peeling adhesive strength to test plate), the adhesive sheet (width: 25 mm, length: 100 mm) was applied to a SUS304 steel plate. is attached, and the adhesive sheet is peeled off at 180° using a peel strength measuring instrument (peeling speed: 300 mm/min). 7. The method for producing a pressure-sensitive adhesive sheet according to claim 6, wherein the adhesion is performed at a lamination pressure of 0.30 MPa or more. The method for producing an adhesive sheet according to claim 6 or 7, wherein the resin composition for forming an adhesive layer is an adhesive resin composition containing air bubbles. The method for producing a pressure-sensitive adhesive sheet according to any one of claims 6 to 8, wherein the pressure-sensitive adhesive layer-forming resin composition is applied in an amount of 10 g/m ² or more and 100 g/m ² or less. For the adhesive sheet having a base material layer and an adhesive layer, SUS304 steel plate and the above The adhesive layer of an adhesive sheet (width: 25 mm, length: 100 mm) is attached via a double-sided adhesive tape, and after 1 hour from the attachment, a peel strength measuring instrument is used to measure the base layer. A method for measuring the adhesive strength A of the adhesive sheet, wherein 180° peeling (peeling speed: 300 mm/min) is performed so that the adhesive layer is peeled off, and the adhesive strength is measured. For a pressure-sensitive adhesive sheet having at least an adhesive layer, the pressure-sensitive adhesive sheet ( Width: 25 mm, length: 100 mm), and immediately after sticking and 24 hours after sticking, the pressure-sensitive adhesive sheet was peeled off at 180° using a peel strength measuring instrument (peeling speed: 300 mm/min), and measure the adhesion force B.

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