JP7478274B2 - Method for producing a release liner - Google Patents

Description

The present invention relates to a method for producing a release liner that can be used for a pressure-sensitive adhesive sheet with a release liner.

Adhesive sheets with release liners, in which a release liner is laminated to a base sheet via an adhesive layer, are used for purposes such as decoration and display. Such decorative or display adhesive sheets have become widely used in place of the conventional decorative or display methods that use painting, because when applied, all that is required is to peel off the release liner and apply the adhesive layer to the substrate.

When the adhesive sheet is large in area, air pockets are likely to form between the adhesive layer and the adherend during application, which can mar the aesthetic appearance of the adhesive sheet. To solve this problem, a technique is known in which unevenness is provided on the surface of the release liner to allow air to pass between the adhesive layer and the adherend (Patent Documents 1 and 2).

Japanese Patent Application Laid-Open No. 07-224254 Japanese Patent Application Laid-Open No. 07-278508

These adhesive sheets with release liners have an uneven surface on the adhesive layer that allows air to pass through, and are expected to have high adhesive strength. However, once attached to an adherend, it becomes difficult to adjust or reposition the sheet, making it difficult to reposition the sheet.

The present invention aims to provide a pressure-sensitive adhesive sheet with a release liner that has excellent air release properties during application and excellent repositioning suitability, and a release liner that can be used therewith.

In order to solve the above problems, the inventors conducted extensive research and discovered that the objective can be achieved by providing an adhesive sheet with a release liner, which is made by laminating a release liner, an adhesive layer, and a base sheet in this order, in which the release liner has a plurality of parallel stripe-shaped convex portions of a predetermined size on the release treatment surface, and also by providing concave-convex portions of a predetermined size between the stripe-shaped convex portions.

That is, the present invention provides the following method for producing a release liner.
[1] A method for producing a release liner, comprising the steps of:
the release liner has a plurality of parallel stripe-shaped convex portions on a release-treated surface,
the width of the stripe-shaped protrusion is 10 to 150 μm, and the height of the stripe-shaped protrusion is 5 to 40 μm;
the center line distance between the stripe-shaped protrusions is 200 to 1000 μm;
a concave-convex portion is provided between the stripe-shaped convex portions, and a maximum height roughness Rz of the concave-convex portion is larger than 3 μm and smaller than a height of the stripe-shaped convex portions;
The heights of the projections and recesses are not uniform,
the stripe-shaped protrusions are parallel to each other, or are in a lattice shape, a parallelogram shape, a rhombus shape, or a triangle shape;
A method for producing a release liner, comprising the steps of: sandblasting the entire surface of a metal roll, forming a plurality of parallel striped recesses; pressing the metal roll thus obtained against a substrate for a release liner to form a predetermined shape in the substrate for a release liner; and applying a release agent to the substrate for a release liner, thereby forming a plurality of parallel striped protrusions corresponding to the striped recesses of the metal roll, and providing uneven portions of different heights between the striped protrusions, which correspond to the sandblasted surface of the metal roll.

[2] A method for producing a release liner as described in [1], in which the entire surface of a metal roll is sandblasted, and then multiple parallel stripe-shaped recesses are formed by etching.

The adhesive sheet with release liner of the present invention provides an adhesive sheet that has excellent air release properties during application and excellent repositioning suitability, as well as a release liner that can be used therewith.

1 is a cross-sectional view illustrating one embodiment of a pressure-sensitive adhesive sheet with a release liner of the present invention. FIG. 2 is a schematic perspective view showing a release liner of the pressure-sensitive adhesive sheet with a release liner according to one embodiment of the present invention. 1A to 1C are schematic cross-sectional views showing an example of a method of using the pressure-sensitive adhesive sheet.

<<Adhesive sheet with release liner>>
The pressure-sensitive adhesive sheet with release liner of the present invention will be described with reference to the drawings. Note that the drawings used in the following description may show the main parts enlarged for the sake of convenience in order to make the features of the present invention easier to understand, and the dimensional ratios of each component may not necessarily be the same as the actual ones.

Fig. 1 is a cross-sectional view showing an embodiment of a pressure-sensitive adhesive sheet with a release liner according to the present invention, Fig. 2 is a perspective schematic view showing the release liner of this pressure-sensitive adhesive sheet with a release liner.
The adhesive sheet with release liner 1 shown here is composed of a release liner 10, an adhesive layer 20 and a base sheet 30 laminated in this order, and the release liner 10 has a plurality of parallel striped convex portions 11 on its release treated surface in contact with the adhesive layer 20, the width 12 of the striped convex portions 11 being 10 to 150 μm, the height 13 of the striped convex portions 11 being 5 to 40 μm, the center line spacing 14 between the striped convex portions 11 being 200 to 1000 μm, and uneven portions 15 being provided between the striped convex portions 11, and the maximum height roughness Rz of the uneven portions 15 being greater than 3 μm and smaller than the height 13 of the striped convex portions 11.

Figure 3 is a schematic cross-sectional view showing an example of a method of using the adhesive sheet. When using the adhesive sheet 1 with a release liner, the release liner 10 is peeled off, and the adhesive layer 20 side of the remaining adhesive sheet 40 is abutted against the adherend 50. The release liner 10 has a plurality of parallel stripe-shaped convex portions 11 on the release treatment surface that contacts the adhesive layer 20, so that a plurality of parallel stripe-shaped concave portions 22 are formed on the surface of the adhesive layer 20 attached to the surface of the release liner 10. Because of the presence of these stripe-shaped concave portions 22, air can be easily removed by applying pressure with a squeegee or finger during application, and air does not accumulate, so that the adhesive sheet can be easily and neatly attached with good adhesion. In addition, because the release liner 10 has uneven portions 15 between the stripe-shaped convex portions 11, during application, the transfer surface 24 having the unevenness of the adhesive layer 20 corresponding to the uneven portions 15 becomes the initial contact surface with the adherend, and the adhesive sheet can be excellent in suitability for repositioning. After application, the adhesive sheet 40 does not have any dents on the surface of the base sheet 30 or any uneven structure that stands out, which impairs the appearance.

Below, we will explain each layer that makes up the pressure-sensitive adhesive sheet with release liner of the present invention.

<Release Liner>
The release liner has a plurality of parallel stripe-shaped protrusions on its release-treated surface.
The width of the stripe-shaped convex portions is from 10 to 150 μm, preferably from 20 to 130 μm, and more preferably from 40 to 110 μm.

The height of the stripe-shaped convex portions is 5 to 40 μm, preferably 10 to 30 μm, and more preferably 15 to 35 μm.

The center line distance between the stripe-shaped protrusions is 200 to 1000 μm, preferably 300 to 900 μm, and more preferably 400 to 800 μm.

When the release liner has a plurality of parallel stripe-shaped convex portions of the above-mentioned size, a plurality of stripe-shaped concave portions of the above-mentioned size are formed on the surface of the adhesive layer provided on the surface of the release liner, and air can be easily removed during application. It is preferable that the plurality of stripe-shaped convex portions are formed continuously up to the edge of the base sheet. The shape of the plurality of stripe-shaped convex portions of the release liner may be any shape that forms a plurality of stripe-shaped concave portions on the surface of the adhesive layer and allows air to be easily removed during application, and the cross-sectional shape is not important. The cross section of the plurality of stripe-shaped convex portions of the release liner may be approximately square, approximately rectangular, approximately triangular, approximately semicircular, or approximately semi-elliptical.

It is also preferable that the multiple stripe-shaped protrusions of the release liner are parallel and regularly spaced at equal intervals. By arranging the multiple stripe-shaped protrusions parallel and regularly spaced at equal intervals, the multiple stripe-shaped recesses on the surface of the adhesive layer after application can be made less noticeable even when the base sheet is transparent or translucent.

The multiple stripe-shaped protrusions 11 of the release liner 10 may be parallel to each other, for example, as shown in FIG. 2, may be in a lattice shape with parallel protrusions and those that intersect at right angles, may be in a parallelogram or rhombus shape with parallel protrusions and those that intersect at a predetermined angle, or may be in a triangular shape with parallel protrusions and those that intersect at a predetermined angle.

The release liner has projections and recesses between the stripe-shaped projections.
The maximum height roughness Rz of the uneven portion is greater than 3 μm, preferably greater than 5 μm, and more preferably greater than 7 μm. The maximum height roughness Rz of the uneven portion is smaller than the height of the stripe-shaped convex portion, and is preferably smaller than 80% of the height of the stripe-shaped convex portion, and more preferably smaller than 70% of the height of the stripe-shaped convex portion.

The release liner has the striped convex portions, and uneven portions are provided between the striped convex portions. By making the uneven portions of the above size, the adhesive layer is point-bonded to the adherend when the adhesive sheet is applied, which provides excellent air release properties and excellent repositioning suitability.

It is preferable that the height of the uneven portions of the release liner is not uniform. By having uneven heights of the uneven portions, it is possible to provide better repositioning suitability.

The release liner is a release liner substrate with at least one surface subjected to a release treatment. The release liner substrate is not particularly limited, and examples thereof include laminated paper in which a thermoplastic resin such as polyethylene is laminated onto a paper substrate such as fine paper, glassine paper, or coated paper; or plastic films such as polyester films such as polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate; or polyolefin films such as polypropylene or polyethylene. Furthermore, a laminate film in which these films are laminated may be used.

Releasers used in the peeling process include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, wax-based, and rubber-based release agents, but alkyd-based, silicone-based, and fluorine-based release agents are particularly preferred because they are heat resistant.

To use the above release agent to perform a release treatment on the surface of a film or other substrate for a release liner, the release agent can be applied directly without solvent, or diluted with a solvent or made into an emulsion, using a gravure coater, bar coater, air knife coater, roll coater, or the like, and the release liner to which the release agent has been applied can be subjected to room temperature or heating, or cured with an electron beam to form a release agent layer. There is no particular limit to the thickness of the release agent layer, but it is generally about 0.05 to 5 μm.

There are no particular limitations on the thickness of this release liner, but it is usually about 10 to 250 μm, and preferably about 20 to 200 μm.

(Method of Manufacturing Release Liner)
The method for producing the release liner involves forming a predetermined shape on a release liner substrate by a conventional method using an embossing roll or the like, and then coating the substrate with a release agent such as silicone to provide a release-treated surface.
For example, after sandblasting the entire surface of a metal roll, a plurality of parallel striped depressions are etched, and the metal roll thus obtained is pressed against a release liner substrate to form a predetermined shape in the release liner substrate, and a release agent is then applied to produce a release liner 10 having a plurality of parallel striped protrusions 11 corresponding to the striped depressions of the metal roll, and uneven portions 15 of different heights corresponding to the sandblasted surface of the metal roll between these striped protrusions 11.
In addition, after etching the entire surface of a metal roll into a conical shape of a certain depth, a plurality of parallel striped depressions are etched, and the metal roll thus obtained is pressed against a release liner substrate to form a predetermined shape in the release liner substrate, and a release agent is then applied to produce a release liner 10 having a plurality of parallel striped protrusions 11 corresponding to the striped depressions of the metal roll, and irregularities 15 between these striped protrusions 11 that are regularly aligned in height to correspond to the conical etched surface of the metal roll.

<Base sheet>
The substrate sheet used in the pressure-sensitive adhesive sheet of the present invention is not particularly limited, and may be any of various plastic sheets, papers, etc. that are commonly used as substrate sheets for pressure-sensitive adhesive sheets having a conventional pressure-sensitive adhesive layer. A decorative layer such as a printed layer, a printed lettering layer, a vapor deposition layer, a sputtering layer, etc., or a functional layer such as a hard coat, a stain prevention coat, or a glossiness adjustment coat may be formed on the surface of the above-mentioned material.

Examples of such plastic sheets include polyolefin resins such as polyethylene, polypropylene, and various olefin copolymers; polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polystyrene resins, polyvinyl chloride resins, acrylic resins, polycarbonate resins, polyamide resins, polyurethane resins, fluorine resins such as polytetrafluoroethylene, polybutene, polybutadiene, polymethylpentene, ethylene-vinyl acetate copolymers, ethylene (meth)acrylic acid copolymers, ethylene (meth)acrylic acid ester copolymers, ABS resins, and ionomer resins; thermoplastic elastomers containing components such as polyolefins, polyurethanes, polystyrenes, polyvinyl chloride, and polyesters, and sheets made of mixtures or laminates of these resins.

Furthermore, these plastic sheets may be subjected to corona treatment or primer treatment, if desired, in order to improve adhesion to layers such as an adhesive layer, a printing layer, or an ink receiving layer that are provided thereon.
The paper used may be fine paper, art paper, coated paper, kraft paper, etc. When paper is used for the base sheet, the basis weight is usually selected in the range of 40 to 120 g/ ^m2 .

The thickness of the base sheet is not particularly limited, but is usually selected within the range of 20 to 500 μm, preferably 30 to 300 μm.
Here, the "thickness of the base sheet" means the thickness of the entire base sheet, and for example, the thickness of a base sheet consisting of multiple layers means the total thickness of all layers constituting the base sheet. Note that, as a method for measuring the thickness of the base sheet, for example, a method of measuring the thickness at any five points using a contact thickness meter and calculating the average of the measured values can be mentioned.

<Adhesive Layer>
As the pressure-sensitive adhesive layer, a known pressure-sensitive adhesive layer can be appropriately used.
The adhesive layer can be formed using an adhesive composition containing various components for constituting the adhesive layer. The ratio of the contents of the components in the adhesive composition that do not vaporize at room temperature is usually the same as the ratio of the contents of the components in the adhesive layer. In this specification, "room temperature" means a temperature that is not particularly cooled or heated, that is, an ordinary temperature, and examples of the temperature include a temperature of 15 to 30°C.

The adhesive composition used to form the adhesive layer is not particularly limited, and any one can be appropriately selected from those commonly used in the adhesive layer of conventional adhesive sheets. For example, acrylic adhesives, rubber adhesives, silicone adhesives, polyurethane adhesives, polyester adhesives, etc. can be used. In addition, it may be any of emulsion type, solvent type, or solventless type, and may be any of crosslinked type or non-crosslinked type.
Examples of acrylic adhesives include copolymers made of a monomer that imparts adhesiveness, a monomer that imparts cohesive strength, and a monomer that contains a crosslinkable functional group, which are crosslinked with a crosslinking agent.
Examples of the monomer that imparts adhesion include alkyl (meth)acrylates such as butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and octyl (meth)acrylate.
Examples of the monomer that imparts cohesive strength include methyl (meth)acrylate, vinyl acetate, styrene, and acrylonitrile.
Examples of monomers containing a functional group include (meth)acrylic acid, maleic acid, itaconic acid, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and N-methylol (meth)acrylamide.
Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, and a metal chelate-based crosslinking agent.

In addition to the above-mentioned components, the adhesive composition may further contain various additives such as colorants (pigments, dyes), antidegradants, antistatic agents, flame retardants, and ultraviolet light.

The thickness of the adhesive layer can be appropriately selected depending on the purpose, but is preferably 5 to 100 μm, more preferably 5 to 80 μm, and particularly preferably 5 to 60 μm. Here, the "thickness of the adhesive layer" means the thickness of the entire adhesive layer, and for example, the thickness of an adhesive layer consisting of multiple layers means the total thickness of all layers that make up the adhesive layer. The thickness of the adhesive layer can be measured, for example, by using a contact thickness meter to measure the thickness at any five points and calculating the average of the measured values.

The adhesive composition is obtained by blending the components that make up the adhesive layer, such as an acrylic copolymer.

<<Method of manufacturing a pressure-sensitive adhesive sheet with a release liner>>
The pressure-sensitive adhesive sheet with a release liner can be produced by laminating the above-mentioned layers in order so that they are in the corresponding positional relationship. The method for forming each layer is as described above.

For example, the above-mentioned adhesive composition can be applied to the release-treated surface of a release liner and dried as necessary to laminate an adhesive layer onto the release-treated surface of the release liner, and the adhesive layer formed on the release-treated surface of the release liner can be attached to a substrate sheet to form an adhesive sheet with a release liner. The surface of the adhesive layer on the release liner side of the adhesive sheet with a release liner will have a surface shape that is an inverse transfer of the shape of the release-treated surface of the release liner.

It is also possible to form an adhesive sheet with a release liner by coating the above-mentioned adhesive composition on a substrate sheet and drying it as necessary to laminate an adhesive layer on the substrate sheet, and then bonding the release-treated surface of a release liner to the adhesive layer formed on the substrate sheet. In this case as well, the surface of the adhesive layer on the release liner side of the adhesive sheet with a release liner will have a surface shape that is an inverse transfer of the shape of the release-treated surface of the release liner.

The adhesive composition can be applied to the release-treated surface of the release liner or the surface of the base sheet by a known method, such as a method using various coaters, such as an air knife coater, blade coater, bar coater, gravure coater, roll coater, roll knife coater, curtain coater, die coater, knife coater, screen coater, or kiss coater.

If necessary, the applied pressure-sensitive adhesive composition may be crosslinked by heating. Heating conditions can be, for example, 80 to 130°C for 1 to 5 minutes, but are not limited thereto.

The present invention will be described in more detail below with reference to examples of pressure-sensitive adhesive sheets with release liners. However, the present invention is not limited to the examples shown below.

[Method for measuring maximum height roughness Rz of uneven parts]
In accordance with JIS B0601:2013, the surface roughness of the uneven portion between the stripe-shaped convex portions was measured using "SURFTEST SV-3000" manufactured by Mitutoyo Corporation, and the maximum height roughness Rz of the uneven portion was obtained.

[Air release (air pocket disappearance) test]
A sample was cut to 50 mm x 50 mm, the release liner was removed, and the adhesive sheet was attached to a melamine-coated board so as to create a circular air pocket with a diameter of 15 mm. The adhesive sheet was then pressed with a squeegee and evaluated according to the following criteria.
○: The air pocket disappeared.
×: The air pocket did not disappear.

[Repositioning aptitude test]
The adhesive sheet with release liner was cut to a width of 50 mm and a length of 100 mm to prepare a test specimen. A flat melamine-coated plate was prepared by wiping the surface with ethanol as a base material to which the adhesive sheet was attached. The release liner was then peeled off from the adhesive sheet with release liner, and the test specimen was placed so that the adhesive layer was in contact with the melamine-coated plate. After 10 seconds, the adhesive sheet was moved (slid) in a direction along the base material while the adhesive layer of the adhesive sheet was in contact with the melamine-coated plate.
◯: The adhesive sheet could be moved smoothly in the direction along the base material.
Δ: The adhesive sheet was able to be moved in the direction along the base material, although there was some snagging.
×: The adhesive sheet could not be moved in the direction along the base material.

[Example 1]
(Production of base sheet)
A composition for a base sheet obtained by melting the following base resin was formed into a film having a thickness of 80 μm by a calendar to obtain a base sheet.

Base Resin:
Polyvinyl chloride (PVC): 100 parts by weight, dioctyl phthalate: 20 parts by weight, epoxy plasticizer: 5 parts by weight, barium zinc stabilizer: 2 parts by weight, titanium oxide (pigment): 10 parts by weight

(Production of Pressure-Sensitive Adhesive Composition)
92 parts by mass of butyl acrylate and 8 parts by mass of acrylic acid as monomer components, 200 parts by mass of ethyl acetate as solvent, and 0.2 parts by mass of azobisisobutyronitrile as polymerization initiator were mixed in a reactor. The mixture was degassed with nitrogen gas for 4 hours, gradually heated to 60°C, and then polymerized for 24 hours while stirring to obtain an ethyl acetate solution (dry mass concentration 33% by mass) containing an acrylic copolymer with a weight average molecular weight of 650,000. An adhesive composition was obtained by adding 1 part by mass of an isocyanate-based crosslinking agent to 100 parts by mass of the ethyl acetate solution.

(Manufacture of Release Liner)
The entire surface of the metal roll was sandblasted and then etched to create a plurality of parallel striped depressions. The metal roll thus obtained was pressed against the polyethylene surface of a release liner substrate consisting of a paper substrate laminated with polyethylene, thereby forming a surface of the specified shape shown in Figure 2 on the release liner substrate. A release agent made of silicone was then applied to a thickness of 0.1 µm to produce the release liner of Example 1, which has a plurality of parallel striped protrusions 11 corresponding to the striped depressions of the metal roll, and uneven portions 15 of uneven heights between these striped protrusions 11, which correspond to the sandblasted surface of the metal roll.
The width of the striped convex portions of the obtained release liner was 80 μm, the height of the striped convex portions was 20 μm, the center line spacing between the striped convex portions was 600 μm, and the maximum height roughness Rz of the uneven portions of non-uniform height between the striped convex portions was 10.2 μm.

(Manufacture of pressure sensitive adhesive sheets with release liners)
The adhesive composition was applied to this release liner of Example 1 so that the adhesive layer would have a thickness of 30 μm after drying, and after drying at 90° C. for 1 minute, the adhesive composition was transferred to the base sheet to form an adhesive layer, thereby producing the adhesive sheet with release liner of Example 1. The performance evaluation results of this adhesive sheet are shown in Table 1.

[Example 2] (Reference Example)
(Manufacture of Release Liner)
The entire surface of the metal roll was etched into a conical shape of a fixed depth, and then a number of parallel striped recesses were etched. The metal roll thus obtained was pressed against the polyethylene surface of a release liner substrate consisting of a paper substrate laminated with polyethylene, thereby forming a surface of a specified shape on the release liner substrate. A release agent made of silicone was then applied to a thickness of 0.1 μm, thereby producing the release liner of Example 2, which has a number of parallel striped protrusions 11 corresponding to the striped recesses of the metal roll, and conical unevenness 15 of a fixed height corresponding to the etched surface of the metal roll between these striped protrusions 11.
The resulting release liner had a width of 80 μm, a height of 20 μm, a center line distance between the stripe-shaped convex portions of 600 μm, and a maximum height roughness Rz of the constant height cone-shaped irregular portions between the stripe-shaped convex portions of 10.0 μm.

(Manufacture of pressure sensitive adhesive sheets with release liners)
The adhesive composition was applied to the release liner of Example 2 in the same manner as in Example 1 so that the adhesive layer would have a thickness of 30 μm after drying, and after drying at 90° C. for 1 minute, the adhesive was transferred to the base sheet to form an adhesive layer, thereby producing the adhesive sheet with release liner of Example 2. The performance evaluation results of this adhesive sheet are shown in Table 1.

[Comparative Example 1]
Except for adjusting the conditions for the sandblasting treatment of the entire surface of the metal roll so that the maximum height roughness Rz of the uneven portion was 1.2 μm, a PSA sheet with a release liner of Comparative Example 1 was produced in the same manner as in Example 1. The performance evaluation results of this PSA sheet are shown in Table 1.

[Comparative Example 2]
A PSA sheet with a release liner of Comparative Example 2 was produced in the same manner as in Comparative Example 1, except that the conditions for the etching process of the metal roll to form a plurality of parallel stripe-shaped recesses were adjusted so that the width of the stripe-shaped protrusions was 8 μm and the height of the stripe-shaped protrusions was 5 μm. The performance evaluation results of this PSA sheet are shown in Table 1.

[Comparative Example 3]
Except for adjusting the conditions for the etching treatment of the metal roll to form a plurality of parallel stripe-shaped recesses so that the height of the stripe-shaped protrusions was 3 μm, a PSA sheet with a release liner of Comparative Example 3 was produced in the same manner as in Comparative Example 1. The performance evaluation results of this PSA sheet are shown in Table 1.

In the release-liner adhesive sheets of Examples 1 and 2, the width of the striped convex portions was 10 to 150 μm, the height of the striped convex portions was 5 to 40 μm, the center line distance between the striped convex portions was 200 to 1000 μm, and uneven portions were provided between the striped convex portions, and the maximum height roughness Rz of the uneven portions was greater than 3 μm and smaller than the height of the striped convex portions, so that the air escape property during construction was excellent and the suitability for repositioning was also good. In the release-liner adhesive sheet of Comparative Example 1, the height of the striped convex portions was 5 μm or more, so that the air escape property was good, but the maximum height Rz of the uneven portions was 3 μm or less, so that the suitability for repositioning was poor. In the release-liner adhesive sheet of Comparative Example 2, the maximum height roughness Rz of the uneven portions was 3 μm or less, the width of the striped convex portions was less than 10 μm, so that the air escape property was poor and the suitability for repositioning was also poor. In the adhesive sheet with release liner of Comparative Example 3, the maximum height roughness Rz of the uneven portion was 3 μm or less, the height of the striped convex portion was less than 5 μm, and the air release properties and repositioning suitability were also poor.

The adhesive sheet with release liner of the present invention has excellent air release properties during application and is easy to reposition, making it suitable for use as advertising labels, decorative labels, display labels, etc. on the exterior and interior walls and window glass of buses, trains, passenger cars, airplanes, etc.

1: adhesive sheet with release liner, 10: release liner, 20: adhesive layer, 30: substrate sheet, 40: adhesive sheet, 50: adherend, 11: striped convex portion, 12: width of striped convex portion, 13: height of striped convex portion, 14: center line distance between striped convex portions, 15: uneven portion, 22: striped concave portion, 24: transfer surface with unevenness

Claims (2)

1. A method for making a release liner, comprising:
the release liner has a plurality of parallel stripe-shaped convex portions on a release-treated surface,
the width of the stripe-shaped protrusion is 10 to 150 μm and the height of the stripe-shaped protrusion is 5 to 40 μm;
the center line distance between the stripe-shaped protrusions is 200 to 1000 μm;
a concave-convex portion is provided between the stripe-shaped convex portions, and a maximum height roughness Rz of the concave-convex portion is larger than 3 μm and smaller than a height of the stripe-shaped convex portions;
The heights of the projections and recesses are not uniform,
the stripe-shaped protrusions are parallel to each other, or are in a lattice shape, a parallelogram shape, a rhombus shape, or a triangle shape;
A method for producing a release liner, comprising the steps of: sandblasting the entire surface of a metal roll, forming a plurality of parallel striped recesses; pressing the metal roll thus obtained against a substrate for a release liner to form a predetermined shape in the substrate for a release liner; and applying a release agent to the substrate for a release liner, thereby forming a plurality of parallel striped protrusions corresponding to the striped recesses of the metal roll, and providing uneven portions between the striped protrusions, the uneven portions having uneven heights corresponding to the sandblasted surface of the metal roll. The method for producing the release liner according to claim 1, in which the entire surface of the metal roll is sandblasted, and then multiple parallel stripe-shaped recesses are formed by etching.

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