WO2021166188A1

WO2021166188A1 - Release liner, adhesive sheet, and method for manufacturing adhesive sheet

Info

Publication number: WO2021166188A1
Application number: PCT/JP2020/006915
Authority: WO
Inventors: 慈齋藤; 章悟杉浦
Original assignee: リンテック株式会社
Priority date: 2020-02-20
Filing date: 2020-02-20
Publication date: 2021-08-26
Also published as: JPWO2021166188A1

Abstract

[Problem] To provide a release liner capable of suppressing bubble formation between an adhesive layer and a base material layer, an adhesive sheet, and a method for manufacturing the adhesive sheet. [Solution] A release liner 100 has a plurality of first ridges 101 and a plurality of second ridges 102 that linearly extend on one surface thereof and has an elongated shape. The first ridges extend obliquely with respect to the longitudinal direction D1 of the release liner and reach edges 103 of the release liner in the width direction D2 orthogonal to the longitudinal direction. The second ridges extend while intersecting the first ridges and reach the edges of the release liner. The plurality of first ridges and the plurality of second ridges form parallelogram-shaped recessed sections 104 as viewed from a direction perpendicular to the surface of the release liner. In the parallelogram, each of the two angles θ opposing in the longitudinal direction D1 is smaller than 90°.

Description

Peeling liner, adhesive sheet, and method of manufacturing the adhesive sheet

The present invention relates to a release liner, an adhesive sheet, and a method for manufacturing an adhesive sheet.

Conventionally, when the adhesive sheet is attached to the adherend, a shape for discharging air bubbles has been studied for the adhesive layer in contact with the adherend so that air bubbles do not enter between them and cause swelling. For example, Patent Document 1 discloses that a plurality of micro-convex portions scattered in an island shape are formed in the pressure-sensitive adhesive layer. On the other hand, Patent Document 2 discloses that a groove is formed on the surface of the pressure-sensitive adhesive layer, and when the pressure-sensitive adhesive sheet is attached to the adherend in a predetermined attachment direction to the groove, air bubbles are generated through the groove. Effectively discharged.

The shape of these pressure-sensitive adhesive layers can be formed by transferring the shape of the release liner that overlaps the pressure-sensitive adhesive layer. For example, in Patent Document 3, the pressure-sensitive adhesive layer is reliably adhered to the lattice-like surface of the release liner. The shape of the release liner is accurately transferred to the pressure-sensitive adhesive layer.

Japanese Patent No. 3377439 International Publication No. 2003/025078 Japanese Patent No. 5236854

However, when the present inventors formed the pressure-sensitive adhesive layer on the release liner having a grid-like surface shape as in Patent Document 3, the surface of the pressure-sensitive adhesive layer has irregularities according to the surface shape of the release liner. Therefore, when a base material layer is placed on the pressure-sensitive adhesive layer and bonded together while being pressed by a roller, air bubbles are trapped between the depression on the surface of the pressure-sensitive adhesive layer and the base material layer. It has been clarified that this may cause a decrease in adhesion between the pressure-sensitive adhesive layer and the base material layer and a poor appearance.

The present invention has been made to solve such a newly found problem, and manufactures a release liner, a pressure-sensitive adhesive sheet, and a pressure-sensitive adhesive sheet capable of suppressing the formation of bubbles between the pressure-sensitive adhesive layer and the base material layer. The purpose is to provide a method.

The release liner of the present invention for achieving the above object is long, with a plurality of linearly extending first ridges and a plurality of second ridges provided on one surface. The first ridge portion extends obliquely with respect to the longitudinal direction of the release liner and reaches the edge of the release liner in the width direction (cross direction) orthogonal to the longitudinal direction (machine direction). The ridge portion extends while intersecting with the first ridge portion to reach the edge of the release liner. The plurality of the first ridges and the plurality of second ridges form parallelogram recesses when viewed from a direction perpendicular to the surface of the release liner, and the parallelogram is the parallelogram. Each of the two opposing corners in the longitudinal direction is less than 90 °.

The pressure-sensitive adhesive sheet of the present invention for achieving the above object has the release liner, the pressure-sensitive adhesive layer, and the base material layer in this order in the stacking direction.

In the method for producing an adhesive sheet of the present invention for achieving the above object, an adhesive layer is formed on the surface of the release liner, and a base material layer is laminated on the adhesive layer and pressed in the longitudinal direction. The base material layer and the pressure-sensitive adhesive layer are bonded together.

According to the invention having the above structure, when the pressure-sensitive adhesive layer is formed on the release liner and is bonded to the base material layer, it is difficult for bubbles to be trapped between them, and bubbles are formed between the pressure-sensitive adhesive layer and the base material layer. Can be suppressed.

It is a top view which shows the release liner of 1st Embodiment. It is the schematic which shows the manufacturing method of the pressure-sensitive adhesive sheet of 1st Embodiment. It is a top view which shows the bonding of the pressure-sensitive adhesive layer and the base material layer in one comparative example. It is a top view which shows the bonding of the pressure-sensitive adhesive layer and the base material layer in another comparative example. It is sectional drawing which follows the 5-5 line of FIG. 3 or FIG. It is sectional drawing which shows the flattening of the surface of the pressure-sensitive adhesive layer progressing from the state of FIG. FIG. 3 is a plan view showing a portion where air is easily captured when the surface of the pressure-sensitive adhesive layer is flattened from the state of FIG. FIG. 5 is a plan view showing a portion where air is easily captured when the surface of the pressure-sensitive adhesive layer is flattened from the state of FIG. It is a top view which shows the bonding of the pressure-sensitive adhesive layer and the base material layer of 1st Embodiment. FIG. 5 is a plan view showing that when the surface of the pressure-sensitive adhesive layer is flattened from the state of FIG. 9, the portion where air is easily captured is suppressed. It is a top view which shows the release liner of 2nd Embodiment. It is a partially enlarged view of the cross section along the longitudinal direction of the release liner of 2nd Embodiment. It is a partially enlarged view which shows the cross section along the longitudinal direction of the release liner of 2nd Embodiment and the adhesive layer dried on the surface thereof in the longitudinal direction.

Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. The dimensional ratios in the drawings are exaggerated for convenience of explanation and differ from the actual ratios.

<First Embodiment>
As shown in FIG. 1, the release liner 100 of the first embodiment has a plurality of linearly extending first ridges 101 and a plurality of second ridges 102 on one surface, and has a length. It is a shaku.

The material for forming the release liner 100 is not particularly limited, and may be formed of, for example, a resin film such as polyethylene terephthalate, or may be formed of paper coated with a resin such as polyethylene. The first ridge 101 and the second ridge 102 are formed by, for example, embossing such a resin film or paper.

The first ridge portion 101 extends obliquely with respect to the longitudinal direction D1 of the release liner 100 and reaches the edge 103 of the release liner 100 in the width direction D2 orthogonal to the longitudinal direction D1. The second ridge 102 extends while intersecting the first ridge 101 to reach the edge 103.

The plurality of first ridges 101 and the plurality of second ridges 102 form rhombic (parallelogram) recesses 104 when viewed from a direction perpendicular to the surface of the release liner 100. The rhombus of the recess 104 has an acute angle at two angles θ facing each other in the longitudinal direction D1, and the length L1 of the diagonal line connecting the two angles θ is longer than the length L2 of the diagonal line connecting the other two angles different from the two angles θ. (L1> L2).

As shown in FIG. 2, the release liner 100 is used for manufacturing the adhesive sheet 1000. The pressure-sensitive adhesive sheet 1000 has a release liner 100, a pressure-sensitive adhesive layer 110, and a base material layer 120 in this order in the stacking direction.

The adhesive sheet 1000 is cut into an appropriate shape after manufacturing, and is used as, for example, a marking film to be attached to the exterior material of a vehicle such as a motorcycle, stickers for advertising or display, a marking film used for a signboard, or the like. However, the intended use of the adhesive sheet 1000 is not particularly limited.

The pressure-sensitive adhesive sheet 1000 was used by peeling off the release liner 100 during use, and the shapes of the first ridge portion 101 and the second ridge portion 102 were transferred to the surface of the pressure-sensitive adhesive layer 110 exposed thereby. A groove is formed. Since the first ridge portion 101 and the second ridge portion 102 reach the edge 103 as shown in FIG. 1, the groove communicates with the outside at the edge of the pressure-sensitive adhesive layer 110, and thus adheres. When the sheet 1000 is attached to the adherend via the pressure-sensitive adhesive layer 110, air bubbles entering between them are effectively discharged from between the pressure-sensitive adhesive layer 110 and the adherend, and the pressure-sensitive adhesive sheet 1000 swells. To prevent.

In the method for manufacturing the pressure-sensitive adhesive sheet 1000, the pressure-sensitive adhesive layer 110 is first formed on the release liner 100, and then the base material layer 120 is bonded to the pressure-sensitive adhesive layer 110.

The pressure-sensitive adhesive layer 110 is formed by drying the pressure-sensitive adhesive 111 applied to the release liner 100. The pressure-sensitive adhesive 111 is not particularly limited, and for example, an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, a styrene-based block copolymer pressure-sensitive adhesive, and a vinyl alkyl ether. Examples include system adhesives. These may be used alone or in combination of two or more.

The adhesive 111 is applied to the release liner 100 on the surface where the first ridge 101 and the second ridge 102 are provided. The pressure-sensitive adhesive 111 is applied thicker than the height T1 of the first ridge portion 101 and the second ridge portion 102, but the thickness of the coating is not particularly limited. The height T1 of the first ridge portion 101 and the second ridge portion 102 is, for example, 5 μm to 35 μm. The pressure-sensitive adhesive 111 is coated with, for example, a knife coater so as to have a predetermined thickness, but the coating means is not particularly limited. If the pressure-sensitive adhesive 111 contains a solvent or water, it is dried after coating.

The pressure-sensitive adhesive 111 is conveyed in the longitudinal direction D1 together with the release liner 100, and is dried while passing through the drying oven H. The release liner 100 is conveyed by, for example, a roll-to-roll method. The drying oven H dries the pressure-sensitive adhesive 111 with, for example, hot air or radiant heat, but the method of drying is not particularly limited.

Before drying, the surface of the pressure-sensitive adhesive layer 110 is substantially flat, but as the solvent and the like are removed from the pressure-sensitive adhesive 111 by drying and the thickness of the pressure-sensitive adhesive layer 110 decreases, the first ridge portion 101 and It is deformed according to the shape of the second ridge portion 102. As a result, as shown by reference numeral 2 in FIG. 2, the surface of the pressure-sensitive adhesive layer 110 has a rhombus shape substantially similar to the rhombus shape of the recess 104 formed by the first ridge portion 101 and the second ridge portion 102. A recess 112 is formed.

After drying, the pressure-sensitive adhesive layer 110 is further conveyed together with the release liner 100 with the recess 112 formed on the surface thereof, and the base material layer 120 is bonded to the pressure-sensitive adhesive layer 110. The material for forming the base material layer 120 is, for example, polyvinyl chloride and polyurethane, but is not limited thereto.

The base material layer 120 is continuously supplied in accordance with the transportation of the release liner 100 and the pressure-sensitive adhesive layer 110, and is superimposed on the surface of the pressure-sensitive adhesive layer 110. The base material layer 120 is pressed by a cylindrical roller R in a state of being overlapped with the pressure-sensitive adhesive layer 110, and the base material layer 120 and the pressure-sensitive adhesive layer 110 are bonded to each other in the longitudinal direction D1.

By pressing from the roller R, the dents 112 on the surface of the pressure-sensitive adhesive layer 110 are smoothed to form a substantially uniform thickness T2 of, for example, about 15 μm to 50 μm, and the pressure-sensitive adhesive layer 110 and the base material layer 120 are in close contact with each other without gaps. However, in the experience of the present inventors, a release liner having a surface shape different from that of the present embodiment is used, and as a result, the pressure-sensitive adhesive layer having a depression different from that of the present embodiment is limited to that. Not.

For example, as in the comparative example shown in FIG. 3, if a rectangular or square recess 112A having two sides orthogonal to the longitudinal direction D1 is formed on the surface of the pressure-sensitive adhesive layer 110A, after pressing by the roller R, Bubbles may be formed between the base material layer 120 and the pressure-sensitive adhesive layer 110A.

Further, even when the diamond-shaped recess 112B is formed on the surface of the pressure-sensitive adhesive layer 110B as in another comparative example shown in FIG. 4, the shape of the rhombus is different from that of the above embodiment, and in the longitudinal direction D1. If the two opposite angles are obtuse and the diagonal line in the longitudinal direction D1 is shorter than the diagonal line orthogonal to the diagonal line, bubbles are formed between the base material layer 120 and the pressure-sensitive adhesive layer 110B after being pressed by the roller R. was there.

Although each of the

recesses

112A and 112B has the same size as the recess 112 of the above embodiment, it is considered that the reason why bubbles are formed is due to the shape.

As shown in FIGS. 5 and 6, the surfaces of the pressure-sensitive

adhesive layers

110A and 110B are flattened while passing through the contact portion R1 between the roller R and the base material layer 120, and the

recesses

112A and 112B are the pressure-sensitive adhesive layers 110A. , 110B is crushed in the direction opposite to the transport direction. At that time, on the upstream side in the transport direction, air is easily caught by the side walls forming the

recesses

112A and 112B.

As shown in FIGS. 7 and 8, in the comparative example, until just before the

points

113A and 113B where such air is easily captured pass through the contact points R1 between the roller R and the base material layer 120 and are flattened. Since it remains wide without being crushed, it is considered that bubbles are likely to be formed.

Such bubbles may reduce the adhesion between the base material layer 120 and the pressure-sensitive adhesive layer 110A, or between the base material layer 120 and the pressure-sensitive adhesive layer 110B, or may be visually recognized as swelling and have a poor appearance. It is not preferable because it may occur.

On the other hand, in the present embodiment, as shown in FIGS. 9 and 10, the side wall 114 constituting the recess 112 is caused by the characteristic shape formed by them (a shape substantially similar to the rhombic shape of the recess 104 of the peeling liner 100). Then, since it is gradually flattened with transportation, it is considered that the portion 113 where air is easily captured is small, and the formation of bubbles between the pressure-sensitive adhesive layer 110 and the base material layer 120 is suppressed.

<Second Embodiment>
As shown in FIG. 11, the release liner 200 of the second embodiment has a plurality of first ridge portions 201 and second ridge portions 202 formed on one surface, similarly to the first embodiment. The plurality of first ridges 201 and the plurality of second ridges 202 intersect with each other to form a recess 104 similar to that of the first embodiment.

The first ridge portion 201 has a cross-sectional shape different from that of the first ridge portion 101 of the first embodiment, and the second ridge portion 202 has a cross-sectional shape different from that of the second ridge portion 102 of the first embodiment. Have different cross-sectional shapes.

As shown in FIG. 12, the cross-sectional shapes of the first ridge portion 201 and the second ridge portion 202 in the longitudinal direction D1 are triangular. Other than this, the release liner 200 is the same as the release liner 100 of the first embodiment. Further, the method for manufacturing the pressure-sensitive adhesive sheet using the release liner 200 is also the same as the manufacturing method for the first embodiment shown in FIG.

As shown in FIG. 13, when the pressure-sensitive adhesive layer 110 is dried during its production, the pressure-sensitive adhesive layer 110 has a triangular cross-sectional shape in the first ridge portion 201 and the second ridge portion 202 in the present embodiment. The surface of the above is also deformed so as to form the

portions

213 and 214 protruding in a substantially triangular shape following them.

When the protruding

portions

213 and 214 are substantially triangular, the protruding portions are when the pressing force F acts, as compared with the case where the shape is trapezoidal or rectangular and the pressing force F from the roller R is received on the surface. The 213 and 214 are easily crushed toward the recess 112 side between them, and the recess 112 can be eliminated more effectively to prevent the formation of bubbles.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims.

For example, in the first embodiment, as shown in FIG. 2, the first ridge 101 and the second ridge 102 have a rectangular cross-sectional shape, and in the second embodiment, FIG. As shown in the above, the first ridge portion 201 and the second ridge portion 202 have a triangular cross-sectional shape, but are not limited to these forms. For example, a first ridge portion and a second ridge portion having a cross-sectional shape different from that of the above embodiment, such as a trapezoid or a chevron with rounded vertices, are also included in the scope of the present invention.

Further, the pressure-sensitive adhesive sheet 1000 of the above embodiment has a release liner 100, a pressure-sensitive adhesive layer 110, and a base material layer 120, but a pressure-sensitive adhesive sheet provided with layers other than these is also included in the scope of the present invention.

100, 200 peeling liner,
101, 201 1st ridge,
102, 202 2nd ridge,
103 The edge of the release liner in the width direction,
104 recess,
110 The pressure-sensitive adhesive layer of the embodiment,
110A, 110B Adhesive layer of Comparative Example,
111 Adhesive,
112 Depression of the pressure-sensitive adhesive layer of the embodiment,
112A, 112B Depression of the adhesive layer of the comparative example,
120 substrate layer,
1000 adhesive sheet,
D1 longitudinal direction,
D2 Width direction orthogonal to the longitudinal direction,
H drying oven,
L1 Diagonal line connecting two opposite corners in the longitudinal direction,
L2 Diagonal line connecting the same two angles and other two angles,
R roller,
Contact point between R1 roller and base material layer,
θ Two angles facing each other in the longitudinal direction.

Claims

A long peeling liner in which a plurality of linearly extending first ridges and a plurality of second ridges are provided on one surface.
The first ridge portion extends obliquely with respect to the longitudinal direction of the release liner and reaches the edge of the release liner in the width direction orthogonal to the longitudinal direction.
The second ridge portion extends while intersecting with the first ridge portion to reach the edge of the release liner.
The plurality of first ridges and the plurality of second ridges form parallelogram recesses when viewed from a direction perpendicular to the surface of the release liner.
The parallelogram is a peeling liner in which each of the two opposing corners in the longitudinal direction is smaller than 90 °.
The release liner according to claim 1, wherein the cross-sectional shape of the first ridge portion and the second ridge portion in the longitudinal direction is a triangle.
An adhesive sheet having the release liner, the adhesive layer, and the base material layer according to claim 1 or 2 in this order in the stacking direction.
A pressure-sensitive adhesive layer is formed on the surface of the release liner according to claim 1 or 2, and the base material layer and the pressure-sensitive adhesive are applied in the longitudinal direction while pressing the base material layer on the pressure-sensitive adhesive layer. An adhesive sheet manufacturing method in which layers are bonded together.