JP2020094099A - Adhesive sheet - Google Patents

Abstract

To provide an adhesive sheet capable of suppressing adhesion of a silicone compound to a surface of an adhesive sheet substrate while suppressing occurrence of a tunneling phenomenon at an interface between a release agent layer and an adhesive layer.SOLUTION: An adhesive sheet 1 has a laminated structure in which an adhesive sheet substrate 11, an adhesive layer 12, a release agent layer 13, and a release material substrate 14 are laminated in this order. The release agent layer 13 is formed of a release agent composition containing a non-silicone thermoplastic resin (A) as a main agent and containing a silylated polyolefin (B). The adhesive layer 12 is formed of an adhesive composition containing a spherical adhesive (C).SELECTED DRAWING: Figure 1

Description

The present invention relates to an adhesive sheet. More specifically, the present invention relates to a removable pressure-sensitive adhesive sheet.

Removable pressure-sensitive adhesive sheets are used in various applications such as physical distribution management labels and office supplies.
Removable pressure-sensitive adhesive sheets are generally required to have both conflicting performances, that is, pressure-sensitive adhesiveness and peelability. For example, at the time of use, it is required to exhibit sufficient adhesiveness even on a rough surface such as a corrugated cardboard, while not easily peeling off. When peeling the re-peelable pressure-sensitive adhesive sheet from the adherend, it is required to have a capability of peeling cleanly without causing adhesive residue on the adherend or damage to the adherend. In addition, there is a case where the ability to repeatedly apply and remove the adherend is required.

Examples of the removable pressure-sensitive adhesive sheet include those having a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing a spherical pressure-sensitive adhesive. By using such an adhesive layer, it is possible to achieve both appropriate adhesiveness and releasability with respect to the adherend.
For example, Patent Document 1 discloses a removable pressure-sensitive adhesive sheet using a pressure-sensitive adhesive elastomeric copolymer as a spherical pressure-sensitive adhesive, and exposes a part of the spherical pressure-sensitive adhesive from the surface of the pressure-sensitive adhesive layer. Thus, the contact area when the pressure-sensitive adhesive layer and the adherend are brought into contact with each other is suppressed, and the sticking property, the peeling property, and the re-sticking property of the pressure-sensitive adhesive sheet are made compatible.

JP-A-50-2736

By the way, when the removable pressure-sensitive adhesive sheet is distributed as a product, in order to protect the pressure-sensitive adhesive layer, a release material having a release agent layer provided on a release material substrate is laminated on the pressure-sensitive adhesive layer. It Conventionally, a releasable pressure-sensitive adhesive sheet generally has a release agent layer of a release material formed of a silicone-based release agent composition.
However, the release agent layer formed of the silicone-based release agent composition has excellent releasability, and therefore it is difficult to maintain the laminated state when the adhesive force of the adhesive layer in contact with the release agent layer is low. It was For example, when performing rewinding for applying some processing to the pressure-sensitive adhesive sheet, the release material floats from the pressure-sensitive adhesive layer in a straight line in parallel with the axial direction of the guide roll when the pressure-sensitive adhesive sheet passes through the guide roll, a so-called tunneling phenomenon. Could happen. In particular, when a spherical pressure-sensitive adhesive is used in the pressure-sensitive adhesive composition, the pressure-sensitive adhesive layer and the release agent layer are held in point contact, so that such a tunneling phenomenon occurs remarkably. When tunneling occurs in the pressure-sensitive adhesive sheet, there are problems that it becomes impossible to process the pressure-sensitive adhesive sheet, and dust adheres to the surface of the pressure-sensitive adhesive layer so that desired pressure-sensitive adhesive properties cannot be obtained.

When the release agent layer of the release material is formed of a silicone-based release agent composition, in the process of winding the release material into a roll during the manufacturing process, the release agent layer-laminated surface of the release material base material is When the surface on the opposite side (hereinafter, also referred to as “base material surface for release material”) and the release agent layer contact, the silicone compound derived from the silicone-based release agent composition may adhere to the surface of the release material base material. is there.
Then, in the process of laminating the release material on the pressure-sensitive adhesive layer and winding the laminate into a roll, the silicone compound adhered to the surface of the release material substrate supports the pressure-sensitive adhesive layer. The adhesive layer may adhere to the surface opposite to the laminated surface (hereinafter, also referred to as “adhesive sheet substrate surface”).
The surface of the pressure-sensitive adhesive sheet substrate may be used as a printing/printing surface or a writing surface. Therefore, when the silicone compound adheres to the surface of the pressure-sensitive adhesive sheet substrate, ink repellency or the like is likely to occur, and printing/printing failure or writing failure may occur.

It is an object of the present invention to provide a pressure-sensitive adhesive sheet that can suppress the adhesion of a silicone compound to the surface of a pressure-sensitive adhesive sheet substrate while suppressing the occurrence of a tunneling phenomenon at the interface between the release agent layer and the pressure-sensitive adhesive layer. And

The present inventors have conducted extensive studies, the release agent layer, by containing a non-silicone thermoplastic resin as a main component, and a layer formed from a release agent composition containing a silylated polyolefin, It has been found that the above problems can be solved.

That is, the present invention relates to the following [1] to [4].
[1] A pressure-sensitive adhesive sheet having a laminated structure in which a base material for pressure-sensitive adhesive sheet, a pressure-sensitive adhesive layer, a release agent layer, and a base material for release material are laminated in this order, wherein the release agent layer is a non-silicone type. A layer comprising a release agent composition containing a thermoplastic resin (A) as a main agent and a silylated polyolefin (B), wherein the pressure-sensitive adhesive layer contains a spherical pressure-sensitive adhesive (C). A pressure-sensitive adhesive sheet, which is a layer formed from.
[2] The pressure-sensitive adhesive sheet according to the above [1], wherein the non-silicone thermoplastic resin (A) is an olefin resin (A1) other than the silylated polyolefin (B).
[3] The mass ratio (B/A) of the content of the silylated polyolefin (B) to the content of the non-silicone thermoplastic resin (A) is 1/99 to 30/70, [1] Alternatively, the pressure-sensitive adhesive sheet according to [2].
[4] The pressure-sensitive adhesive sheet according to any one of the above [1] to [3], which has a peel force of 200 to 800 mN/25 mm when peeling the release agent layer from the pressure sensitive adhesive layer.

According to the present invention, it is possible to provide a pressure-sensitive adhesive sheet capable of suppressing the adhesion of a silicone compound to the surface of a pressure-sensitive adhesive sheet substrate while suppressing the occurrence of a tunneling phenomenon at the interface between the release agent layer and the pressure-sensitive adhesive layer. Is possible.

It is a schematic sectional drawing of the pressure sensitive adhesive sheet of one mode of the present invention.

In the present specification, the “active ingredient” refers to the ingredient contained in the composition excluding the diluent solvent.
Further, in the present invention, with respect to a preferable numerical value range (for example, the range of the content or the like), the lower limit value and the upper limit value described stepwise can be independently combined. For example, from the description "preferably 10 to 90, more preferably 30 to 60", the "preferable lower limit value (10)" and the "more preferable upper limit value (60)" are combined to obtain "10 to 60". You can also

The pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet having a laminated structure in which a pressure-sensitive adhesive sheet substrate, a pressure-sensitive adhesive layer, a release agent layer, and a release material substrate are laminated in this order, wherein the release agent layer is A layer formed from a release agent composition containing a non-silicone thermoplastic resin (A) as a main component and a silylated polyolefin (B), wherein the pressure-sensitive adhesive layer contains a spherical pressure-sensitive adhesive (C). A pressure-sensitive adhesive sheet, which is a layer formed from a pressure-sensitive adhesive composition.
Hereinafter, the constitution of the pressure-sensitive adhesive sheet of the present invention will be described, and then the pressure-sensitive adhesive sheet base material, pressure-sensitive adhesive layer, release agent layer, and release material base material which constitute the pressure-sensitive adhesive sheet of the present invention will be described. Then, the characteristics, the manufacturing method, and the use of the pressure-sensitive adhesive sheet of the present invention will be further described.

[Structure of adhesive sheet]
The pressure-sensitive adhesive sheet of the present invention has a laminated structure in which a pressure-sensitive adhesive sheet substrate, a pressure-sensitive adhesive layer, a release agent layer, and a release material substrate are laminated in this order.
FIG. 1 is a schematic cross-sectional view showing an adhesive sheet of one embodiment of the present invention. The pressure-sensitive adhesive sheet 1 has a laminated structure in which a pressure-sensitive adhesive sheet base material 11, a pressure-sensitive adhesive layer 12, a release agent layer 13, and a release material base material 14 are laminated in this order. In other words, in the pressure-sensitive adhesive sheet 1, the release sheet 15 including the pressure-sensitive adhesive sheet base material 11, the pressure-sensitive adhesive layer 12, and the release agent layer 13 and the release material base material 14 is laminated in this order, and the release material 15 is released. It has a laminated structure in which the agent layer 13 side is in direct contact with the adhesive layer 12.
In the pressure-sensitive adhesive sheet 1 shown in FIG. 1, the pressure-sensitive adhesive sheet substrate 11 and the pressure-sensitive adhesive layer 12, the pressure-sensitive adhesive layer 12 and the release agent layer 13, the release agent layer 13 and the release material substrate 14 are different from each other. It is directly laminated without any interposition. That is, the pressure-sensitive adhesive sheet 1 shown in FIG. 1 is a pressure-sensitive adhesive sheet including only the pressure-sensitive adhesive sheet base material 11, the pressure-sensitive adhesive layer 12, the release agent layer 13, and the release material base material 14. However, the pressure-sensitive adhesive sheet of the present invention is not limited to such an embodiment, and between the pressure-sensitive adhesive sheet substrate 11 and the pressure-sensitive adhesive layer 12, between the pressure-sensitive adhesive layer 12 and the release agent layer 13, and peeling. Another layer may be provided at least between the agent layer 13 and the release material substrate 14. Further, another layer may be provided on at least one of the surface of the adhesive sheet base material 11 and the surface of the release material base material 14.

[Base material for adhesive sheet]
The pressure-sensitive adhesive sheet base material of the pressure-sensitive adhesive sheet of the present invention is not particularly limited as long as it functions at least as a support for the pressure-sensitive adhesive layer, and among the pressure-sensitive adhesive sheet base materials used in conventional pressure-sensitive adhesive sheets. Therefore, it is appropriately selected depending on the purpose of use of the pressure-sensitive adhesive sheet.
Examples of such a base material for an adhesive sheet include papers such as kraft paper, high-quality paper, glassine paper, parchment paper, rayon paper, coated paper, and synthetic fiber paper; polyester resin, polyvinyl chloride resin, Resin films such as polyvinylidene chloride resin and polyolefin resin; synthetic paper and the like.
The pressure-sensitive adhesive sheet substrate may be a single layer or a multilayer of two or more layers of the same kind or different kinds.
Further, a coating layer may be provided on the surface of the pressure-sensitive adhesive sheet substrate. Examples of the coat layer include a print-receiving layer in consideration of printability for various displays, but are not necessarily limited to the print-receiving layer, and include scratch resistance, storability, waterproofness, and designability. Various coat layers in consideration may be provided.
The coat layer may be a single layer or a multilayer of two or more layers of the same kind or different kinds.

The thickness of the pressure-sensitive adhesive sheet base material is appropriately selected depending on the purpose of use of the pressure-sensitive adhesive sheet and the like, but from the viewpoint of handleability, it is preferably 10 to 200 μm, more preferably 20 to 150 μm, further preferably 30 to 100 μm. Is.

When a synthetic resin is used as the pressure-sensitive adhesive sheet base material, the surface of the pressure-sensitive adhesive sheet base material that is in contact with the pressure-sensitive adhesive layer, in order to improve the adhesion between the pressure-sensitive adhesive sheet base material and the pressure-sensitive adhesive layer, If desired, the surface treatment can be performed by a method such as an oxidation method or a textured method.
Examples of the oxidation method include corona discharge surface treatment, chromic acid surface treatment (wet), flame surface treatment, hot air surface treatment, ozone/ultraviolet irradiation surface treatment, and the like. Further, examples of the uneven method include a sandblast method and a solvent treatment method. These surface treatment methods are appropriately selected according to the type of the substrate for pressure-sensitive adhesive sheets, but in general, the corona discharge surface treatment method is preferably used from the viewpoint of effect and operability. Further, a primer treatment can be applied.
When a coating layer is provided on the surface of the pressure-sensitive adhesive sheet substrate, these surface treatments may be performed on the pressure-sensitive adhesive sheet substrate surface.

[Adhesive layer]
The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present invention is formed from a pressure-sensitive adhesive composition containing a spherical pressure-sensitive adhesive (C).
In the removable pressure-sensitive adhesive sheet, the pressure-sensitive adhesive layer has a relatively high adhesive force when lightly pressed and adhered to an adherend, and the adhesive force does not increase so much even when strongly pressed and adhered. The ability to be peeled off with a relatively small force is desired. Further, it is also desired to have a property capable of suppressing a part of the pressure-sensitive adhesive layer from being transferred to the surface of the adherend when peeled off, resulting in adhesive residue or damage to the adherend. Furthermore, the ability to re-adhere to another adherend with good adhesiveness after peeling is also desired.
From such a viewpoint, in the present invention, the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition containing the spherical pressure-sensitive adhesive (C) is used. In such an adhesive layer, a part of the adhesive microsphere particles derived from the spherical adhesive (C) contained in the adhesive composition is exposed on the surface of the adhesive layer. Therefore, when the adherend is brought into contact with the adhesive layer, the contact area between the adherend and the adhesive layer can be suppressed. Therefore, the pressure-sensitive adhesive layer can have both appropriate adhesiveness and releasability with respect to the adherend, and the above performance can be ensured.

Note that the pressure-sensitive adhesive composition of one aspect of the present invention may include a pressure-sensitive adhesive additive, if necessary.
Hereinafter, each component contained in the pressure-sensitive adhesive composition which is a material for forming the pressure-sensitive adhesive layer will be described.

<Spherical adhesive (C)>
The pressure-sensitive adhesive composition contains a spherical pressure-sensitive adhesive (C).
The spherical pressure-sensitive adhesive (C) is not particularly limited as long as it is a pressure-sensitive adhesive composed of spherical fine particles, and a known spherical pressure-sensitive adhesive that is usually used when forming a pressure-sensitive adhesive layer of a removable pressure-sensitive adhesive sheet. Can be used.
Specific examples of the spherical adhesive (C) include acrylic spherical adhesives and rubber spherical adhesives.
The spherical adhesive (C) may be used alone or in combination of two or more.
Among these, it is preferable to use the acrylic spherical pressure-sensitive adhesive (C1) from the viewpoint of facilitating control of appropriate adhesiveness and releasability to the adherend.

The acrylic spherical adhesive (C1) is a spherical adhesive made of an acrylic polymer. As the acrylic polymer, an acrylic homopolymer obtained by polymerizing one kind of acrylic monomer, an acrylic copolymer obtained by polymerizing two or more kinds of acrylic monomers, and An acrylic copolymer obtained by polymerizing an acrylic monomer and a monomer other than the acrylic monomer can be used.
In the acrylic spherical pressure-sensitive adhesive (C1), the acrylic polymer and the acrylic copolymer may be used alone or in combination of two or more.

Specific examples of the acrylic monomer include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth). ) Acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, etc. Is a (meth)acrylic acid ester having an alkyl group of 1 to 20; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth). Hydroxyalkyl (meth)acrylates such as acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate; acrylamide, methacrylamide, N-methylacrylamide, N,N-dimethylacrylamide, N-methylmethacrylamide. , N,N-dimethylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, and other acrylamides; (meth)acrylic acid mono- or dialkylamino such as methylaminoethyl (meth)acrylate and dimethylaminoethyl (meth)acrylate. Alkyl; (meth)acrylic acid and the like can be mentioned.
In addition, in this specification, "(meth)acrylic acid" refers to both "acrylic acid" and "methacrylic acid", and the same applies to other similar terms.

Specific examples of monomers other than acrylic monomers include ethylenically unsaturated carboxylic acids such as crotonic acid, maleic acid, itaconic acid and citraconic acid; vinyl esters such as vinyl acetate and vinyl propionate; ethylene, Olefins such as propylene and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; styrene-based monomers such as styrene and α-methylstyrene; diene-based monomers such as butadiene, isoprene and chlorobrene; acrylonitrile and methacryl Examples thereof include nitrile-based monomers such as ronitrile.

Here, the polymer constituting the acrylic spherical pressure-sensitive adhesive (C1) may be crosslinked with an internal crosslinking agent or an external crosslinking agent.
The internal cross-linking agent refers to a reactive monomer capable of introducing a cross-linking structure into the polymer molecule during polymerization.
The external cross-linking agent means a compound capable of reacting with a cross-linkable functional group existing in the polymer molecule to introduce a cross-linked structure.

Specific examples of the internal crosslinking agent include polyfunctional ethylenically unsaturated monomers and keto group-containing ethylenically unsaturated monomers.
The internal crosslinking agents may be used alone or in combination of two or more.
When the internal cross-linking agent is used, the internal cross-linking agent is blended in the monomer mixture. The blending amount of the internal crosslinking agent is preferably 5 parts by mass or less with respect to 100 parts by mass of the monomer component.

Specific examples of the external cross-linking agent include isocyanate compounds, epoxy compounds, melamine compounds, aziridine (ethyleneimine) compounds, hydrazide compounds, oxazoline compounds, carbodiimide compounds, urea compounds, dialdehyde compounds, Examples thereof include metal chelate compounds, metal alkoxides and metal salts.
The external crosslinking agents may be used alone or in combination of two or more.
When an external crosslinking agent is used, the external crosslinking agent is added to the obtained polymerization reaction solution or dispersion. The compounding amount of the external crosslinking agent is preferably 5 parts by mass or less based on 100 parts by mass of the polymer.

The acrylic spherical adhesive can be obtained as an aqueous suspension of the spherical adhesive by a conventionally known method such as a suspension polymerization method or a method of suspending the solution in water after solution polymerization.

The average particle size of the particles of the spherical pressure-sensitive adhesive (C) blended in the pressure-sensitive adhesive composition is usually 1 to 200 μm, preferably 10 to 100 μm, more preferably 15 to 50 μm. When the average particle size of the spherical pressure-sensitive adhesive (C) particles blended in the pressure-sensitive adhesive composition is in the above range, the pressure-sensitive adhesive layer is lightly pressed against the adherend to make the adhesive force relatively high. It is easy, and the adhesive force does not increase so much even when it is strongly pressed and adhered, and it is easy to peel off with a relatively small force. Further, when peeled off, it is easy to prevent a part of the pressure-sensitive adhesive layer from being transferred to the surface of the adherend to cause adhesive residue or damage to the adherend. In addition, after peeling, it is easy to adhere to another adherend again with good adhesiveness.

The average particle size of the particles of the spherical pressure-sensitive adhesive (C) blended in the pressure-sensitive adhesive composition is, for example, about 100 particles are randomly selected from an electron micrograph, and the average value is calculated by measuring the particle size. You can ask for it. When the particles are not spherical, the major axis and the minor axis may be obtained and the average value may be assumed to be the particle diameter of the particle.

<Binder adhesive>
The pressure-sensitive adhesive composition contains a spherical pressure-sensitive adhesive (C) and a binder pressure-sensitive adhesive.
The binder pressure-sensitive adhesive is not particularly limited as long as it can fix the spherical pressure-sensitive adhesive (C) to the pressure-sensitive adhesive sheet base material.
Specific examples of the binder pressure-sensitive adhesive include a pressure-sensitive adhesive having an emulsion containing a (meth)acrylic acid ester-based polymer as a main component (hereinafter, also referred to as "acrylic emulsion-type pressure-sensitive adhesive").
Here, the "main component" means a component having the largest content (mass ratio) in the binder pressure-sensitive adhesive, and preferably 50 mass% or more, preferably 50 mass% or more, based on the total amount (100 mass%) of the binder pressure-sensitive adhesive. It means a component accounting for 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, still more preferably 90% by mass or more.

As the (meth)acrylic acid ester-based polymer, any one can be appropriately selected and used from the (meth)acrylic acid ester-based polymers used in a usual acrylic pressure-sensitive adhesive.
Specific examples of such (meth)acrylic acid ester-based polymer include homopolymers or copolymers obtained by polymerizing one or more acrylic acid ester-based monomers, or acrylic acid ester-based monomers. And a copolymer obtained by polymerizing a monomer other than the acrylic acid ester-based monomer.
Specific examples of the monomer used when producing the (meth)acrylic acid ester-based polymer include the same as those shown in the acrylic spherical adhesive (C1).

The (meth)acrylic acid ester-based polymer may be crosslinked with an internal crosslinking agent or an external crosslinking agent.
Specific examples of the internal cross-linking agent and the external cross-linking agent include the same as those exemplified in the description of the spherical pressure-sensitive adhesive (C).

The acrylic emulsion type pressure-sensitive adhesive can be produced by a known method.
For example, an acrylic emulsion-type pressure-sensitive adhesive can be produced by adding a predetermined monomer to an aqueous medium containing an emulsifier, performing emulsification treatment, and performing emulsion polymerization in the presence of a polymerization initiator.
The average particle size of the micelles in the acrylic emulsion pressure-sensitive adhesive is not particularly limited. The range of the average particle diameter is usually 100 to 2000 nm, preferably 120 to 1500 nm, and particularly preferably 150 to 500 nm.

<Other additives>
In one aspect of the present invention, the pressure-sensitive adhesive composition may include an additive for pressure-sensitive adhesive, if necessary.
Examples of the additive for pressure-sensitive adhesives include tackifiers, plasticizers, fillers, antiaging agents, ultraviolet absorbers, preservatives, antifungal agents, dyes, pigments, and fragrances.
The content of these additives is usually 10 parts by mass or less, preferably 1 to 5 parts by mass with respect to the total amount (100 parts by mass) of the pressure-sensitive adhesive composition.

<Content and content ratio of each component in the pressure-sensitive adhesive composition>
In one aspect of the present invention, the mass ratio of the spherical pressure-sensitive adhesive (C) and the active ingredient of the acrylic emulsion-type pressure-sensitive adhesive contained in the pressure-sensitive adhesive composition (spherical pressure-sensitive adhesive (C): acrylic emulsion-type pressure-sensitive adhesive) is It is preferably 100:75 to 100:250, more preferably 100:80 to 100:220.
By setting the mass ratio of the spherical PSA (C) contained in the PSA composition to the active ingredient of the acrylic emulsion-type PSA within the above range, the adhesion between the PSA substrate and the PSA layer can be improved. Easy to use. In addition, it is easy to improve the re-adhesion property to the adherend.

<Diluting solvent>
The pressure-sensitive adhesive composition is diluted with water, for example, and used in the form of an aqueous solution.
Specifically, an aqueous solution of the pressure-sensitive adhesive composition can be obtained by mixing an aqueous suspension of the spherical pressure-sensitive adhesive (C), an acrylic emulsion-type pressure-sensitive adhesive, the above-mentioned additives and the like.
The amount of water may be appropriately selected so that the pressure-sensitive adhesive composition has an appropriate viscosity when applied.

[Release agent layer]
The release agent layer of the pressure-sensitive adhesive sheet of the present invention may be a layer formed of a release agent composition containing a non-silicone thermoplastic resin (A) as a main component and a silylated polyolefin (B), The release agent composition may include an additive for a release agent, if necessary.
In one embodiment of the present invention, the total content of the components (A) and (B) in the release agent composition is based on the total amount (100% by weight) of the release agent composition, and preferably 70% by weight or more, It is more preferably 80% by mass or more, still more preferably 90% by mass or more, still more preferably 95% by mass or more.
Hereinafter, each component contained in the release agent composition which is a material for forming the release agent layer will be described.

<Non-silicone thermoplastic resin (A)>
The release agent composition contains a non-silicone thermoplastic resin (A) as a main component.
In addition, in this specification, a "main component" means a component with the largest content (mass ratio) in a release agent composition, Preferably it is 50 based on the total amount (100 mass%) of a release agent composition. It means a component that accounts for more than mass %.
In one aspect of the present invention, the content of the non-silicone thermoplastic resin (A) in the release agent composition is the release agent composition from the viewpoint of easily controlling the release force of the release agent layer to an appropriate value. The total amount (100% by mass) is preferably 50 to 99% by mass, more preferably 60 to 97% by mass, and further preferably 65 to 95% by mass.

The non-silicone thermoplastic resin (A) is not particularly limited as long as it is a thermoplastic resin that does not substantially contain a silicone compound.
In the present specification, “thermoplastic resin substantially free of silicone compound” means excluding a thermoplastic resin in which a silicone compound is intentionally blended with a specific motive. .. Specifically, the content of the silicone compound is preferably less than 1.0% by mass, more preferably less than 0.1% by mass, and further preferably 0.01% based on the total amount (100% by mass) of the release agent layer. It means less than mass %.

Specific examples of the non-silicone thermoplastic resin (A) include olefin resins; polyvinyl chloride; polyvinylidene chloride; ethylene vinyl acetate copolymers; ethylene/methyl methacrylate copolymers; polyesters such as polyethylene terephthalate; Polycarbonate; polyamide; ABS resin; polyacetal resin; polyimide; polyurethane; polylactic acid;
The non-silicone thermoplastic resin (A) may be used alone or in combination of two or more.

Here, in one aspect of the present invention, the non-silicone thermoplastic resin (A) is an olefin resin (A1) from the viewpoint of easily controlling the peeling force of the release agent layer to an appropriate value. preferable.
The olefin resin (A1) does not include the silylated polyolefin (B). That is, the olefin resin (A1) is an olefin resin other than the silylated polyolefin (B).

The olefin resin (A1) is a polymer mainly composed of the structural unit (a1) derived from the olefin monomer (a1′).
However, the structural unit (b1) derived from the hydrosilane compound (b1′) containing at least one general formula (1) described below as a structural unit is not included.
Here, the “polymer mainly composed of the structural unit (a1) derived from the olefin monomer (a1′)” means that the structural unit most contained among the structural units contained in the olefin resin (A1) is an olefin. It means that it is the structural unit (a1) derived from the monomer (a1′).
As the olefin monomer (a1′), an olefin having 2 to 8 carbon atoms is preferable. Examples of the olefin having 2 to 8 carbon atoms include ethylene, propylene, butylene, isobutylene, 1-hexene and the like.
In one embodiment of the present invention, the olefin monomer (a1′) is more preferably an olefin having 2 to 4 carbon atoms such as ethylene, propylene and butylene, and is ethylene or propylene being an olefin having 2 to 3 carbon atoms. More preferably.
The olefin monomers (a1′) may be used alone or in combination of two or more to form a copolymer.

When specific examples of the olefin resin (A1), ultra low density polyethylene (VLDPE, density: 880 kg / ^{m 3} or more 910 kg / ^m less than ^3), low density polyethylene (LDPE, density: 910 kg / ^{m 3} or more 915 kg / m polypropylene; 942kg / ^{m 3} or higher), polyethylene resins such as linear polyethylene: ³ below), medium density polyethylene (MDPE, density: 915 kg / ^{m 3} or more 942kg / ^m less than ^3), high density polyethylene (HDPE, density (PP); polybutene resin (PB); ethylene-propylene copolymer; olefin elastomer (TPO); ethylene-vinyl acetate copolymer (EVA); ethylene-methyl methacrylate copolymer (EMMA); ethylene-propylene And an olefinic terpolymer such as -(5-ethylidene-2-norbornene); and the like, preferably polyethylene resin (PE), polypropylene resin (PP), polybutene resin (PB), and more preferably Polyethylene resin (PE) and polypropylene resin (PP).
The olefin resin (A1) may be used alone or in combination of two or more.

The content of the structural unit (a1) in the olefin resin (A1) is preferably 50 to 100% by mass, more preferably 100% by mass based on the total structural units (100% by mass) of the olefin resin (A1). Is 60 to 100% by mass, more preferably 70 to 100% by mass, even more preferably 80 to 100% by mass, still more preferably 90 to 100% by mass.

The content of the structural unit derived from the olefin having 2 to 3 carbon atoms in the olefin resin (A1) is preferably 50 to 100 mass with respect to all the structural units (100 mass%) of the olefin resin. %, more preferably 60 to 100% by mass, still more preferably 70 to 100% by mass, even more preferably 80 to 100% by mass, still more preferably 90 to 100% by mass.

<Silylated polyolefin (B)>
The release agent composition further contains a silylated polyolefin (B).
When the release agent layer is formed of the release agent composition comprising the non-silicone thermoplastic resin (A), the release force becomes too large and it becomes difficult to release the release agent from the pressure-sensitive adhesive layer. Further, when the release agent layer is formed of a release agent composition comprising a silicone-based thermoplastic resin (A) as in the conventional case, the release force is too small and a tunneling phenomenon occurs at the interface between the release agent layer and the pressure-sensitive adhesive layer. It will be easier. Therefore, problems such as deterioration of processability and failure of protecting the pressure-sensitive adhesive layer with a release material are likely to occur.
For these situations, the present inventors use a release agent layer formed from a release agent composition containing a non-silicone thermoplastic resin (A) as a main component and a silylated polyolefin (B). It was found that the release force can be appropriately controlled to suppress the occurrence of the tunneling phenomenon at the interface between the release agent layer and the pressure-sensitive adhesive layer, and further the problem of migration of the silicone compound can be solved.

The silylated polyolefin (B) is a structural unit (b1) derived from a hydrosilane compound (b1′) (hereinafter, also referred to as “monomer (b1′)”) containing one or more of the following general formula (1) as a structural unit. , And a structural unit (b2) derived from a terminal double bond-containing polyolefin (b2′) (hereinafter, also referred to as “monomer (b2′)”).
In the silylated polyolefin (B), -Si-H in the hydrosilane compound (b1') is reacted with -C=C (vinyl group) in the terminal double bond-containing polyolefin (b2'), -Si-. Includes a CC structure.
The polymerization form of the copolymer of the hydrosilane compound (b1′) and the terminal double bond-containing polyolefin (b2′) is not particularly limited and may be a random copolymer, a block copolymer, or a graft copolymer. However, it is preferably a block copolymer.

In the general formula (1), R ¹ represents a hydrocarbon group or a silicon-containing group. R ¹ is preferably a hydrocarbon group, more preferably an aliphatic hydrocarbon group, still more preferably an alkyl group, even more preferably an alkyl group having 1 to 3 carbon atoms, particularly preferably methyl. It is a base.
Y ¹ represents an oxygen atom, a sulfur atom or NR (N is a nitrogen atom and R represents a hydrogen atom or a hydrocarbon group). Y ¹ is preferably an oxygen atom.
When there are a plurality of R ^{1 s} and Y ^{1 s,} they may be the same or different, but are preferably the same.
Here, the hydrosilane compound (b1′) is preferably a compound represented by the following general formula (2).

In the general formula (2), R ¹ and Y ¹ are the same as those in the general formula (1).
R ^1b represents a hydrocarbon group, preferably an aliphatic hydrocarbon group, more preferably an alkyl group, still more preferably an alkyl group having 1 to 3 carbon atoms, and particularly preferably a methyl group. ..
Y ² represents an oxygen atom, a sulfur atom or NR (N is a nitrogen atom and R represents a hydrogen atom or a hydrocarbon group). Y ² is preferably an oxygen atom.
m is an integer of 1 to 20, preferably 1 to 6.
n is an integer of 0 to 20, preferably 0 or 1.
When n is 1 or more, Z represents a divalent linking group represented by the following general formula (4).
When n is 0, Z represents a divalent linking group represented by the following general formula (4) or a direct bond between Y ¹ and R ^1c .
R ^1a and R ^1c represent a hydrocarbon group or a group represented by the following general formula (3). The hydrocarbon group is preferably an aliphatic hydrocarbon group, more preferably an alkyl group, further preferably an alkyl group having 1 to 3 carbon atoms, and particularly preferably a methyl group. However, when n is 0, R ^1c may be a hydrogen atom. When there are a plurality of R ¹ , R ^1a , R ^1b , and R ^1c , these may be the same or different.
When a plurality of Y ¹ and Y ² are present, they may be the same or different, but it is preferable that they are all oxygen atoms.

In the general formula (3), R ²¹ represents a hydrocarbon group, preferably an aliphatic hydrocarbon group, more preferably an alkyl group, further preferably an alkyl group having 1 to 3 carbon atoms, A methyl group is particularly preferred. A plurality of R ^21's may be the same or different, but it is preferable that they are the same.
y is an integer of 1 to 100, preferably 1.

In the general formula (4), R ¹¹ represents a hydrocarbon group, preferably an aliphatic hydrocarbon group, more preferably an alkyl group, further preferably an alkyl group having 1 to 3 carbon atoms, A methyl group is particularly preferred.
A plurality of R ¹¹ may be the same or different, but it is preferable that they are the same.
l is an integer of 0-500.

Further, the hydrosilane compound (b1′) may have a structure represented by the following general formula (5).
In the general formula (5) below, l is the same as in the general formula (4).

The terminal double bond-containing polyolefin (b2′) is a terminal double bond-containing polyolefin containing one or more vinyl groups.
The terminal double bond-containing polyolefin (b2′) is selected from the group consisting of an ethylene homopolymer chain, a propylene homopolymer chain, or an olefin having 2 to 50 carbon atoms, except for the vinyl group of the terminal double bond containing polyolefin. It is preferably a copolymer chain of two or more olefins.
Among these, ethylene homopolymer chains, propylene homopolymer chains, or ethylene, propylene, butene, vinyl norbornene, cyclic polyene having two or more double bonds and chain polyene having two or more double bonds It is preferably a copolymer chain of two or more olefins selected from the group, and particularly ethylene homopolymer chain, propylene homopolymer chain, olefin and diene copolymer chain, ethylene and propylene copolymer chain, ethylene And a copolymer chain of norbornene is preferred.
The number average molecular weight of the terminal double bond-containing polyolefin (b2′) is preferably 100 to 500,000.
The number average molecular weight (Mn) is a standard polystyrene conversion value measured by gel permeation chromatography (GPC) method.

As the silylated polyolefin (B), for example, a hydrosilane compound (b1′) and a terminal double bond-containing polyolefin (b2′) are described in, for example, JP 2010-37555 A and JP 2011-26448 A. In the presence of a transition metal catalyst composition prepared from the hydrosilane compound (b1′) and a transition metal halide.

The amount ratio of the hydrosilane compound (b1′) to the terminal double bond-containing polyolefin (b2′) varies depending on the structure of the silylated polyolefin (B) to be produced, but usually the terminal double bond-containing polyolefin (b2′). ) And the Si-H bond in the hydrosilane compound (b1') are in the range of 0.01 to 10 equivalent times, preferably 0.1 to 2 equivalent times.

Specific examples of the silylated polyolefin (B) include olefin-silicone copolymers having a structure having a polyorganosiloxane block (silicone block) represented by the following general formulas (6) to (8). However, the silylated polyolefin (B) is not limited to these.
In the following general formulas (6) to (8), l and m are the same numerical values as l and m described in the general formulas (2) and (4). The value of 1 is preferably 5 to 200, more preferably 10 to 100 from the viewpoint of easily controlling the peeling force of the release agent layer to an appropriate value.
Further, p is an integer of 1 or more, preferably 100 to 100,000, and more preferably 200 to 10,000.
Further, in the following general formulas (6) to (8), two R ^{31 s} in the terminal double bond-containing polyolefin (b2′) each independently represent a hydrogen atom or a hydrocarbon group. R ³¹ is a residue of an olefin unit constituting a polyolefin. When the olefin is ethylene, both R ^31's are hydrogen atoms. When the olefin is propylene, two R ^31's are a combination of a hydrogen atom and a methyl group. When there are a plurality of p's, the value of p may be the same or different.

In one aspect of the present invention, from the viewpoint of easily controlling the peeling force of the release agent layer to an appropriate value, the content of the silylated polyolefin (B) in the release agent composition is the total amount of the release agent composition (100 % By mass), preferably 1 to 30% by mass, more preferably 3 to 20% by mass, still more preferably 5 to 20% by mass, still more preferably 7 to 20% by mass.

<Other additives>
In one aspect of the present invention, the release agent composition may include an additive for a release agent, in addition to the components (A) and (B) described above, if necessary.
Examples of such additives include antioxidants, ultraviolet absorbers, antistatic agents, surfactants, photoinitiators, and light stabilizers.
The content of these additives is usually 10 parts by mass or less, and preferably 1 to 5 parts by mass with respect to the total amount (100 parts by mass) of the release agent composition.
In addition, in one embodiment of the present invention, the release agent composition may be in a form capable of solution coating by adding a diluting solvent to the above-mentioned various active ingredients.

<Content and content ratio of each component in the release agent composition>
In one embodiment of the present invention, from the viewpoint of easily controlling the release force of the release agent layer to an appropriate value, the mass of the content of the silylated polyolefin (B) with respect to the content of the non-silicone thermoplastic resin (A). The ratio (B/A) is preferably 1/99 to 30/70, more preferably 3/97 to 20/80, further preferably 5/95 to 20/80, and 7 It is even more preferably /93 to 20/80.

<Thickness of release agent layer>
Although the thickness of the release agent layer is not particularly limited, it is usually 5 to 70 μm, preferably 5 to 50 μm, more preferably 5 to 40 μm, further preferably 5 to 30 μm, still more preferably 10 to 20 μm. Is.
The thickness of the release agent layer is measured, for example, by the method described in Examples below.

[Base material for release material]
The release material base material of the pressure-sensitive adhesive sheet of the present invention is not particularly limited as long as it functions as a support for supporting the release agent layer, and among the release material base materials used in conventional release materials. Is selected as appropriate.
Specific examples include the above-mentioned paper base material used as a base material for an adhesive sheet, a resin film or sheet, a base material obtained by laminating a paper base material with a resin, and the like.
The base material for the release material may be a single layer or a multilayer of two or more layers of the same kind or different kinds.
The thickness of the base material for the release material is not particularly limited, but is usually 10 to 300 μm, and preferably 20 to 200 μm. When the thickness of the base material for the release material is 10 to 300 μm, it is possible to give the pressure-sensitive adhesive sheet and the like using the release material the rigidity and strength suitable for processing such as printing, cutting, and pasting.

When a synthetic resin is used as the release material base material, the surface of the release material base material on which the release layer is provided may be optionally oxidized to improve the adhesion between the release material base material and the release layer. The surface treatment can be performed by a method such as a ruggedness method or an uneven method.
Examples of the oxidation method include corona discharge surface treatment, chromic acid surface treatment (wet), flame surface treatment, hot air surface treatment, ozone/ultraviolet irradiation surface treatment, and the like. Further, examples of the uneven method include a sandblast method and a solvent treatment method. These surface treatment methods are appropriately selected according to the type of the base material for the release material, but in general, the corona discharge surface treatment method is preferably used from the viewpoint of effect and operability. Further, a primer treatment can be applied.

[Characteristics of adhesive sheet]
In the pressure-sensitive adhesive sheet of the present invention, the tunneling phenomenon is unlikely to occur at the interface between the pressure-sensitive adhesive layer and the release agent layer. Therefore, the adhesive layer is securely protected by the release material until the time of use.
Moreover, since the silicone compound does not migrate to the surface of the pressure-sensitive adhesive sheet substrate, when the surface is used as a printing/printing surface or a writing surface, printing/printing failure or writing failure is unlikely to occur.
Further, the silicone compound does not migrate to the pressure-sensitive adhesive layer, and the decrease in tack of the pressure-sensitive adhesive layer that may be caused by the migration of the silicone compound can be suppressed.
In addition, the pressure-sensitive adhesive layer included in the pressure-sensitive adhesive sheet of the present invention has both conflicting performances such as tackiness and peelability. Therefore, at the time of use, it does not easily peel off while exhibiting sufficient adhesiveness even on a rough surface. Moreover, when the pressure-sensitive adhesive sheet is peeled off from the adherend, the adhesive sheet can be peeled off neatly without leaving adhesive residue on the adherend or damage to the adherend. In addition, it is possible to repeatedly attach and detach the adherend.

<Peeling force>
In the pressure-sensitive adhesive sheet of one embodiment of the present invention, from the viewpoint of facilitating the occurrence of the tunneling phenomenon at the interface between the release agent layer and the pressure-sensitive adhesive layer, the release agent layer has an appropriate release force for the pressure-sensitive adhesive layer. The release force of the release agent layer from the pressure-sensitive adhesive layer is preferably 200 to 800 mN/25 mm, more preferably 300 to 600 mN/25 mm, and further preferably 330 to 550 mN/25 mm.
The peeling force can be measured by the method described in Examples below.

[Production method of adhesive sheet]
<Method of manufacturing release material>
The method for producing the release material that the pressure-sensitive adhesive sheet of the present invention has is not particularly limited, but for example, a method of extruding the release agent composition onto a release material substrate, release formed using the release agent composition. Examples of the method include a method of attaching the agent layer to a release material substrate, a method of applying a diluting solvent to the above release agent composition to prepare a coatable solution, and applying the solution onto the release material substrate.
There is no particular limitation on the method for applying the solution prepared by adding a diluting solvent to the above-mentioned release agent composition so that it can be applied on the release material substrate, and a known method can be used. Examples thereof include a gravure coating method, a bar coating method, a spray coating method, a roll coating method, a die coating method, a knife coating method, an air knife coating method, a lip coating method and a curtain coating method.

Here, in the release agent layer formed from the release agent composition, migration of the silicone compound to other layers does not occur. Therefore, the silicone compound does not migrate to the surface of the release material base material due to the contact between the release agent layer and the surface of the release material base material when the release material is wound.

<Production method of adhesive sheet>
The method for producing the pressure-sensitive adhesive sheet of the present invention is not particularly limited, for example, an aqueous solution of the above-mentioned pressure-sensitive adhesive composition is prepared, and the aqueous solution of the pressure-sensitive adhesive composition is applied to a pressure-sensitive adhesive sheet substrate to form a pressure-sensitive adhesive layer. A method of forming a pressure-sensitive adhesive sheet by forming the release agent layer and the pressure-sensitive adhesive layer of the release material, and bonding the pressure-sensitive adhesive layer together.

The method for applying the aqueous solution of the pressure-sensitive adhesive composition onto the pressure-sensitive adhesive sheet substrate is not particularly limited, and a known method can be used. Examples thereof include a gravure coating method, a bar coating method, a spray coating method, a roll coating method, a die coating method, a knife coating method, an air knife coating method, a lip coating method and a curtain coating method.

Here, as described above, the silicone compound does not migrate to the surface of the release material substrate of the pressure-sensitive adhesive sheet of the present invention. Therefore, when the pressure-sensitive adhesive sheet is wound up, the silicone compound does not migrate to the pressure-sensitive adhesive sheet base material due to the contact between the release material substrate surface and the pressure-sensitive adhesive sheet base material. Therefore, the silicone compound that may cause printing/printing failure or writing failure does not adhere to the pressure-sensitive adhesive sheet base material, and the printing/printing and writing state of the pressure-sensitive adhesive sheet base material can be improved.

[Use of adhesive sheet]
According to the pressure-sensitive adhesive sheet of the present invention, conflicting performances such as tackiness and releasability are compatible. Therefore, at the time of use, it does not easily peel off while exhibiting sufficient adhesiveness even on a rough surface. Moreover, when the pressure-sensitive adhesive sheet is peeled off from the adherend, the adhesive sheet can be peeled off neatly without leaving adhesive residue on the adherend or damage to the adherend. In addition, it is possible to repeatedly attach and detach the adherend.
Therefore, the pressure-sensitive adhesive sheet according to one embodiment of the present invention utilizes the property of being able to be repeatedly attached to and peeled from such an adherend, and is used for management purposes such as a label for article management, a label for process management, and a label for physical distribution management. It can be used as stationery office supplies such as blindfold labels and fancy labels, advertising and advertisement applications such as POP labels, and play equipment applications.

The present invention will be specifically described by the following examples, but the present invention is not limited to the following examples.
In addition, in the following Examples, "mass %" means mass% in terms of active ingredient with respect to the total amount of the composition.

[Physical properties]
The physical property values in the following examples and comparative examples are values measured by the following methods.

<Measurement of thickness of each layer>
The thickness was measured using a constant pressure thickness meter manufactured by Teclock Co., Ltd. (model number: “PG-02J”, standard: JIS K6783, Z1702, Z1709 compliant).
However, the thickness of the release agent layer was measured using a spectroscopic ellipsometer (manufactured by JA Woollam Japan Co., Ltd., trade name: Spectral Ellipsometry 2000U).

[Examples and Comparative Examples]
The release materials of Examples 1 to 4 and Comparative Examples 1 and 2 were produced by the following procedure.

<Example 1>
As the non-silicone thermoplastic resin (A), a polyethylene resin (Sumitomo Chemical Co., Ltd., trade name: Sumikasen L-405), which is an olefin resin, was used. In the following description, the polyethylene resin is also referred to as “PE resin”.
As the silylated polyolefin (B), a diluted product of polyethylene-silicone-polyethylene triblock copolymer diluted with polyethylene (Mitsui Chemicals, Inc., trade name "EXFORA PE masterbatch", silylated polyolefin content ratio: 30 mass %) was used. In the following description, the diluted product is also referred to as “exfoliator”.
In addition, in this example, polyethylene as a diluent contained in "EXFORA" was added as a component of the non-silicone thermoplastic resin (A).
A release agent composition was prepared by mixing 10 parts by mass of the exfoliator in a dry state with 90 parts by mass of the PE resin.
Then, using the release agent composition, a glassine paper (manufactured by Nippon Paper Industries Co., Ltd., trade name: Joshitsu Y-5K seal 64.0 G, thickness: 73 μm, basis weight: 64 g/m ² ) is used as a release material substrate. As the release agent, a release agent layer having a thickness of 20 μm was formed on the release material base material by extrusion by a laminating method to obtain a release material.

<Examples 2 to 4>
A release material was obtained in the same manner as in Example 1 except that the blending amounts of the PE resin and the exfoliator in the release agent composition were changed as follows.
(Example 2)
・PE resin: 83% by mass
・Exfoliator: 17% by mass
(Example 3)
・PE resin: 75% by mass
・Exfoliator: 25% by mass
(Example 4)
・PE resin: 30% by mass
・Exfoliator: 70% by mass

<Comparative Example 1>
A release material was obtained in the same manner as in Example 1 except that the release agent composition was prepared using only the PE resin without blending the exfoliator.

<Comparative example 2>
100 parts by mass of addition-type polyorganosiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KS835) was diluted with toluene to prepare a 10 mass% solution, and a platinum catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., trade name : PL-50T) was added in an amount of 2 parts by mass to prepare a coating solution of the release agent composition.
Then, the same glassine paper as in Example 1 was used as a base material for the release material, and the coating liquid of the release agent composition was applied on the base material for the release material. The coating amount was 1.0 g/m ² . Then, it was heat-dried at 150° C. for 1 minute to obtain a release material having a release agent layer having a thickness of 1 μm.

[Measurement and evaluation]
The following measurements and evaluations were performed on the release materials of Examples 1 to 4 and Comparative Examples 1 and 2.

<Peel force measurement>
The release materials of Examples 1 to 4 and Comparative Examples 1 and 2 were applied to a removable pressure-sensitive adhesive label (manufactured by Lintec Co., Ltd., trade name: Repeat 1720) containing a spherical pressure-sensitive adhesive in a pressure-sensitive adhesive layer with a 2 kg roller, and the pressure-sensitive adhesive was adhered. Got the sheet.
Then, after pressing at a pressure of 0.5 MPa for 3 hours, the peeling force when the peeling material was peeled off was measured at a sample width of 25 mm, a peeling speed of 300 mm/min, and a peeling angle of 180°.

<Evaluation of silicone transfer amount>
The release materials of Examples 1 to 4 and Comparative Examples 1 and 2 were cut into 15 cm x 15 cm, and a polyethylene terephthalate film (trade name: Diamond Wheel PET38T-100, 15 cm x 15 cm, manufactured by Mitsubishi) was cut on the release material surface. They were brought into contact with each other and pressed at a pressure of 10 MPa for 24 hours. After releasing the press, the amount of Si on the surface of the polyethylene terephthalate film that was in contact with the release material was measured using a fluorescent X-ray analyzer (manufactured by Rigaku Corporation, tabletop wavelength dispersion fluorescent X-ray analysis system "Mini-Z"). did.
When the Si content was below the detection limit (0.5 cps or less), no silicone transfer was performed (○), and when the Si content exceeded the detection limit (0.5 cps), the silicone transfer was performed. Yes (x)

<Floating release material>
The pressure-sensitive adhesive sheet produced at the time of measuring the peeling force was cut into 150 mm×400 mm to prepare a sample for floating evaluation of the release material, and a polyethylene round bar having a diameter of 60 mm was prepared for evaluation.
With the side of the adhesive sheet substrate of the sample of the adhesive sheet as the inner surface and the release material side as the outer surface, the lengthwise direction of the sample was wound along the side surface of the round bar and fixed for 2 hours. After that, the winding was released, and the sample was allowed to stand on a horizontal table with the pressure-sensitive adhesive sheet substrate side facing up and the release material facing down.
The state of the sample was observed after 5 minutes, and the sample in which the release material did not float (tunneling) was rated as ◯, and the sample in which it was generated was rated as x.

The results are shown in Table 1.

The following can be seen from Table 1.
From Comparative Example 1, when the release agent layer was formed only with the non-silicone thermoplastic resin (A), although silicone transfer to the pressure-sensitive adhesive layer and floating of the release material were not observed, the release force was too large. I understand.
Further, from Comparative Example 2, it can be seen that when the release agent layer is formed of only the silicone-based thermoplastic resin, the release force is too small, and the silicone transfer to the pressure-sensitive adhesive layer and the release material float.
On the other hand, in Examples 1 to 4, the peeling force was adjusted to an appropriate range (200 to 800 mN/25 mm), and furthermore, silicone transfer to the pressure-sensitive adhesive layer and floating of the release material were not observed. I understand.

1 Adhesive Sheet 11 Adhesive Sheet Substrate 12 Adhesive Layer 13 Release Agent Layer 14 Release Material Substrate 15 Release Material

Claims (4)

A pressure-sensitive adhesive sheet having a laminated structure in which a pressure-sensitive adhesive sheet substrate, a pressure-sensitive adhesive layer, a release agent layer, and a release material substrate are laminated in this order,
The release agent layer is a layer formed from a release agent composition containing a non-silicone thermoplastic resin (A) as a main component and a silylated polyolefin (B),
A pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive layer is a layer formed from a pressure-sensitive adhesive composition containing a spherical pressure-sensitive adhesive (C). The pressure-sensitive adhesive sheet according to claim 1, wherein the non-silicone thermoplastic resin (A) is an olefin resin (A1) other than the silylated polyolefin (B). The mass ratio (B/A) of the content of the silylated polyolefin (B) to the content of the non-silicone-based thermoplastic resin (A) is 1/99 to 30/70. Adhesive sheet. The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein a peeling force when peeling the release agent layer from the pressure-sensitive adhesive layer is 200 to 800 mN/25 mm.