KR20240009359A - Cover film-attached pressure-sensitive adhesive layer - Google Patents

Abstract

[Problem] To provide an adhesive layer with a cover film suitable for suppressing end blocking and pool contamination.
[Solution] The adhesive layer (X) with a cover film is provided with the cover film 10, the adhesive layer 30, and the cover film 20 in this order in the thickness direction (H). The cover film 10 has a first surface 11 on the side of the adhesive layer 30, and also has a film cross section 12 that forms an acute angle with the first surface 11. The cover film 20 has an extended protruding end 20A. The extended protruding end portion 20A extends outward from the end portion 30A of the adhesive layer 30 in the surface direction D perpendicular to the thickness direction H. The displacement length d of the end portion 30A of the adhesive layer 30 from the film end surface 12 and the extended surface 12' of the film end surface 12 is 5 μm or less.

Description

Cover film attachment adhesive layer {COVER FILM-ATTACHED PRESSURE-SENSITIVE ADHESIVE LAYER}

The present invention relates to an adhesive layer with a cover film.

The display panel has a laminated structure including elements such as, for example, a pixel panel, a polarizing film, a touch panel, and a cover film. In the manufacturing process of such a display panel, for example, a transparent adhesive is used to bond elements included in the laminated structure.

Meanwhile, development of display panels that can be repeatedly bent (foldable) is in progress, for example, for smartphones and tablet terminals. Specifically, the foldable display panel can be repeatedly deformed between a curved shape and a flat, non-bent shape. In such a foldable display panel, each element in the laminated structure is manufactured so that it can be repeatedly bent, and a soft adhesive is used to bond such elements. The sheet-like adhesive (adhesive sheet) for flexible devices such as foldable display panels is described, for example, in Patent Document 1 below.

Japanese Patent Publication No. 2018-111754

Pressure-sensitive adhesive sheets for flexible devices are conventionally manufactured, for example, as follows.

First, as shown in FIG. 6A, a laminated sheet 60 as a long raw material sheet is produced. The laminated sheet 60 includes a release liner 61, an adhesive layer 62, and a release liner 63 in that order in the thickness direction (H). The release liner 61 is in peelable contact with one side of the adhesive layer 62. The release liner 63 is in peelable contact with the other side of the adhesive layer 62.

Next, as shown in FIG. 6B, the adhesive layer 62A in the laminated sheet 60 is punched to form the adhesive layer 62A as a sheet-like adhesive sheet (punched). process). Specifically, a processing blade (not shown) is driven into the adhesive layer 62 on the release liner 61 from the release liner 63 side until it reaches the release liner 61, thereby forming a predetermined planar view. A flat-shaped adhesive layer 62A is formed (the cutting location 65 by the processing blade is schematically indicated by a thick line). A peripheral portion 62a is formed around the adhesive layer 62A. In this process, the release liner 63 is also punched to form a release liner 63A having the same plan view shape as the adhesive layer 62A, and a peripheral portion 63a is created around the release liner 63A.

Next, as shown in FIG. 6C, the peripheral portions 62a and 63a (FIG. 6B) are removed from the release liner 61.

After this, as shown in Fig. 6D, the long release liner 61 is cut into a sheet-shaped release liner 61A. As a result, the sheet-shaped adhesive layer 60' with a cover film (release liner 61A/adhesive layer 62A/release liner 63A) is obtained as a double-sided adhesive sheet with release liner.

The adhesive sheet (adhesive layer) for a flexible device is required to be highly soft so as to have sufficient followability to the adherend when the device is bent and to have excellent stress relaxation properties. However, in the above-described manufacturing method, the softer the adhesive layer 62 is, the easier it is for the adhesive layer 62 to adhere to the processing blade and to be pulled by the processing blade in the punching process (FIG. 6B). Therefore, as shown in FIG. 7, the protruding portion 62E is likely to be formed in the adhesive layer 62A after punching. The protruding portion 62E is a portion in which the end 62e of the adhesive layer 62A extends outward beyond the end 63e of the release liner 63A. The extended protrusion length d' of the protruding portion 62E after the punching process is conventionally long, at 6 μm or more.

The protruding portion 62E causes the ends of adjacent adhesive layers 60' with a cover film to adhere to each other (end blocking) when the adhesive layers 60' with a cover film are stacked. End blocking reduces the handleability of the adhesive layer 60' with a cover film. Additionally, the protruding portion 62E causes full contamination of the adhesive layer 60' with the cover film. These problems occur even when a surface protection film with an adhesive layer (the release liner 61A is attached to the adhesive layer side) is formed on the release liner 61A instead of the adhesive layer 62A and the release liner 63A. , happens.

The present invention provides a pressure-sensitive adhesive layer with a cover film suitable for suppressing end blocking and pool contamination.

The present invention [1] is an adhesive layer with a cover film comprising a first cover film, an adhesive layer, and a second cover film in this order in the thickness direction, wherein the first cover film is on the side of the adhesive layer. It has a first surface and a film cross-section forming an acute angle with the first surface, wherein the second cover film has an extended protruding end, and the extended protruding end has a plane direction perpendicular to the thickness direction. and a pressure-sensitive adhesive layer with a cover film that extends outward beyond the end of the pressure-sensitive adhesive layer, and has a displacement length of the end of the pressure-sensitive adhesive layer from the cross-section of the film and the extended surface of the cross-section of the film of 5 μm or less. .

This invention [2] includes the adhesive layer with a cover film according to the above [1], wherein the gel fraction of the adhesive layer is 80% or less.

This invention [3] includes the adhesive layer with a cover film according to the above [1] or [2], wherein the adhesive layer has a thickness of 5 μm or more and 50 μm or less.

This invention [4] includes the adhesive layer with a cover film according to any one of the above [1] to [3], wherein the acute angle in the first cover film is 40° or more and 85° or less.

In the present invention [5], the pressure-sensitive adhesive layer has an adhesive surface on the side of the second cover film, and has a cross-section of the pressure-sensitive adhesive layer forming an acute angle with the adhesive surface, with respect to the angle of the acute angle of the pressure-sensitive adhesive layer. It includes the cover film attachment adhesive layer described in [4] above, wherein the angle ratio of the acute angle of the first cover film is 0.9 or more and 1.5 or less.

The present invention [6] is any of the above [1] to [5], wherein the difference between the maximum and minimum edge widths of the edge representing the edge of the first cover film in plan view is 10 μm or less. It includes an adhesive layer attached to the cover film.

In the adhesive layer with a cover film of the present invention, as described above, the displacement length (extrusion amount) of the end portion of the adhesive layer from the film cross section and the extended surface of the same cross section is small, 5 μm or less. Such an adhesive layer with a cover film is suitable for suppressing the above-mentioned end blocking and glue contamination.

1 is a cross-sectional schematic diagram of one embodiment of an adhesive layer with a cover film of the present invention.
FIG. 2 is a partially enlarged cross-sectional view of an end portion of the adhesive layer with a cover film shown in FIG. 1.
FIG. 3 is a partially enlarged cross-sectional view of an end portion of a modified example of the adhesive layer with a cover film shown in FIG. 1.
FIG. 4 is a partially enlarged cross-sectional view of an end portion in another modification of the adhesive layer with a cover film shown in FIG. 1.
5A to 5D show a method for producing the adhesive layer with a cover film shown in FIG. 1. Figure 5A shows the laminated sheet manufacturing process, Figure 5B shows the first outline processing process, Figure 5C shows the removal process, and Figure 5D shows the second outline manufacturing process.
Figures 6A to 6D show an example of a conventional method for producing a pressure-sensitive adhesive layer with a cover film. Figure 6A shows the laminated sheet manufacturing process, Figure 6B shows the punching process, Figure 6C shows the removal process, and Figure 6D shows the cutting process.
Fig. 7 is a partially enlarged cross-sectional view of an end portion of a conventional adhesive layer with a cover film.

As an embodiment of the adhesive layer with a cover film of the present invention, the adhesive layer with a cover film (X) includes cover films 10 and 20 and an adhesive layer 30, as shown in FIGS. 1 and 2. . Specifically, the adhesive layer (X) with a cover film is composed of the cover film 10 (first cover film), the adhesive layer 30, and the cover film 20 (second cover film) in the thickness direction H) It is provided in this order. The adhesive layer with a cover film (X) spreads in the plane direction (D) perpendicular to the thickness direction (H).

The cover film 10 is, for example, a transparent surface protection film for flexible devices. The cover film 10 has a first surface 11 on the adhesive layer 30 side and also has a film end surface 12. The first surface 11 and the film end surface 12 form an acute angle. That is, the film cross section 12 is an inclined cross section inclined to form an acute angle with the first surface 11. The adhesive layer 30 is bonded to the first surface 11. The adhesive layer 30 has an adhesive surface 31 on the cover film 20 side. Such a cover film 10 and the adhesive layer 30 form a surface protection film (Y) with an adhesive layer.

End portion 30A of the adhesive layer 30 from the film end surface 12 of the cover film 10 and the extended surface 12' of the film end surface 12 (shown as an imaginary line in FIGS. 2 to 4). The positional deviation length d (amount of extrusion) of ) is 5 μm or less. The positional deviation length d is the maximum length in the direction perpendicular to the film end surface 12 and the extension surface 12'. Figure 2 exemplarily shows the case where the positional deviation length d is 0 μm. Figure 3 exemplarily shows a case where the positional deviation length d is a positive value. The positive value of the displacement length d means that the end portion 30A of the adhesive layer 30 has a portion that protrudes outward from the film end surface 12 and the extension surface 12'. Figure 4 exemplarily shows a case where the positional deviation length d is a negative value. The fact that the positional deviation length d is a negative value means that the end portion 30A of the adhesive layer 30 is sunken inward or retreating from the extended surface 12'. Specifically, the method of measuring the positional deviation length d is as described later in the examples.

The cover film 20 is a release liner. The cover film 20 has a peeling surface 21. The cover film 20 is in peelable contact with the adhesive layer 30 on the peeling surface 21 side. Additionally, the cover film 20 has an extended protruding end portion 20A. The extended protruding end portion 20A extends and protrudes outward from the end portion 30A of the adhesive layer 30 in the surface direction D. Such a cover film 20 is peeled off from the adhesive layer 30 when using the surface protection film (Y) with an adhesive layer.

Such an adhesive layer (X) with a cover film is used, for example, in the manufacturing process of a flexible device, as a supply material for a surface protection film (Y) with an adhesive layer that is incorporated into the laminated structure of the device. Examples of flexible devices include flexible display panels. The flexible display panel has a laminated structure including elements such as a pixel panel, a polarizing film, a touch panel, and a cover film (surface protection film), for example.

In the cover film-attached pressure-sensitive adhesive layer The misalignment length d (amount of protrusion) is small, less than 5 μm. Such an adhesive layer (X) with a cover film is suitable for suppressing the above-mentioned end blocking and glue contamination. Specifically, it is as shown in the later examples and comparative examples.

The positional deviation length d is preferably 4 μm or less, more preferably 3 μm or less, further preferably 2 μm or less, further preferably 1 μm or less, from the viewpoint of suppressing end blocking and grass contamination. It is less than 0.5μm. The misalignment length d is preferably -10 μm or more, more preferably -5 μm or more, and still more preferably - 3μm or more, particularly preferably -0.5μm or more. From the viewpoint of both suppressing the above-mentioned end blocking and pool contamination and ensuring the above-mentioned protection function, the misalignment length d is most preferably 0 μm.

The acute angle α formed by the first surface 11 of the cover film 10 and the film end surface 12 is preferably 40° or more, more preferably 40° or more, from the viewpoint of securing the edge width W described later. It is 45° or more, more preferably 48° or more. The angle α is preferably 85° or less, more preferably 80° or less, and still more preferably 75° or less from the viewpoint of preventing line contamination when the adhesive layer (X) with the cover film is transported from the device manufacturing line. am. As a method of adjusting the angle α, for example, adjustment of laser irradiation conditions in laser processing, which will be described later, is included. Laser irradiation conditions include, for example, the wavelength of the laser light, the pulse width of the laser light, the frequency of the pulse, laser power, and the beam spot diameter of the laser light.

The thickness of the adhesive layer 30 is preferably 5 μm or more, more preferably 10 μm or more, and still more preferably 12 μm or more from the viewpoint of ensuring the adhesive force in the surface protection film (Y) with the adhesive layer. The thickness of the adhesive layer 30 is preferably 50 μm or less, more preferably 40 μm or less, further preferably 30 μm or less, particularly preferably 25 μm or less from the viewpoint of reducing the thickness of the surface protection film (Y) with the adhesive layer. am.

The gel fraction of the adhesive layer 30 is preferably 80% or less, more preferably 75% or less, and even more preferably 70% or less from the viewpoint of ensuring the softness of the adhesive layer 30. From the viewpoint of ensuring the cohesion of the adhesive layer 30, the gel fraction of the adhesive layer 30 is preferably 40% or more, more preferably 45% or more, and even more preferably 50% or more. Examples of methods for adjusting the gel fraction include selection of the type of base polymer in the adhesive layer 30, adjustment of the molecular weight, and adjustment of the compounding amount. The method for measuring the gel fraction is as described later in the Examples.

The shear storage modulus of the adhesive layer 30 at 25°C is preferably 200 kPa or less, more preferably 100 kPa or less, and still more preferably 70 kPa or less from the viewpoint of ensuring the softness of the adhesive layer 30. The shear storage modulus of the adhesive layer 30 at 25°C is preferably 10 kPa or more, more preferably 15 kPa or more, more preferably 20 kPa or more, especially preferably, from the viewpoint of securing the adhesive strength of the adhesive layer 30. It is more than 25kPa. Methods for adjusting the shear storage modulus include, for example, selection of the type of base polymer in the pressure-sensitive adhesive layer 30, adjustment of the molecular weight, and adjustment of the mixing amount. The method for measuring the shear storage modulus is as described later in the Examples.

The adhesive layer 30 preferably has a cross section 32 that forms an acute angle with the adhesive surface 31 . The angle β of this acute angle is preferably 40° or more, more preferably 45° or more, and still more preferably 48° or more in order to secure the edge width W, which will be described later. The angle β is preferably 85° or less, more preferably 80° or less, and still more preferably 75° or less from the viewpoint of preventing line contamination when the adhesive layer (X) with the cover film is transported from the device manufacturing line. am. As a method of adjusting the angle β, for example, adjustment of laser irradiation conditions in laser processing, which will be described later, is included.

The ratio (β/α) of the angle β in the adhesive layer 30 to the angle α in the cover film 10 is preferably 0.9 or more, more preferably 1.00 or more, and still more preferably 1.01. or more, more preferably 1.05 or more, even more preferably 1.10 or more, particularly preferably 1.15 or more, and even more preferably 1.20 or more. The ratio (β/α) is preferably 1.5 or less, more preferably 1.4 or less, and even more preferably 1.3 or less. These configurations are suitable for suppressing false detections by the detection camera when using the area of the edge width W, which will be described later, as an alignment mark for edge detection, and also using the area of the edge width W to create an adhesive layer with a cover film. This is desirable for suppressing measurement errors when measuring dimensions of (X).

Examples of materials for the cover film 10 (surface protection film) include polyimide (PI), polyester, polyolefin, and polycarbonate. Examples of polyester include polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate. Examples of polyolefins include polyethylene, polypropylene, and cycloolefin polymer (COP).

The thickness of the cover film 10 is preferably 10 μm or more, more preferably 15 μm or more, and still more preferably 20 μm or more from the viewpoint of securing the protective function as a surface protection film. The thickness of the cover film 10 is preferably 100 μm or less, more preferably 70 μm or less, and still more preferably 50 μm or less from the viewpoint of reducing the thickness of the surface protection film (Y) with an adhesive layer.

In this embodiment, the cover film 10 has a protruding portion 13 on the side opposite to the adhesive layer 30. The protruding portion 13 protrudes on the side opposite to the adhesive layer 30 on the side of the cover film 10 (second side) opposite to the first side 11. The protruding height of the protruding portion 13 is, for example, 0.1 μm or more, and is, for example, 20 μm or less. Additionally, the protruding portions 13 are arranged along the film end surface 12. Such protrusions 13 are formed by subjecting the cover film 101 to melting by laser irradiation in the first external shape processing process (FIG. 5B) described later using laser processing, thereby forming a cover film ( It is formed along the film cross section 12 of 10).

Examples of materials for the cover film 20 (release liner) include polyester, polyolefin, polycarbonate, and polyimide. Specifically, the material of the cover film 20 includes the materials described above for the cover film 10.

The peeling surface 21 of the cover film 20 is preferably subjected to a peeling treatment. Examples of the peeling treatment include silicone peeling treatment and fluorine peeling treatment.

The thickness of the cover film 20 is preferably 5 μm or more, more preferably 10 μm or more, and still more preferably 15 μm or more from the viewpoint of ensuring the protective function of the adhesive layer 30 by the cover film 20. . The thickness of the cover film 20 is preferably 200 μm or less, more preferably 150 μm or less, and still more preferably 100 μm from the viewpoint of preventing peeling errors when peeling the cover film 20 from the adhesive layer 30. It is as follows.

In the plane direction D, the extended protrusion length of the extended protruding end 20A with respect to the cover film 10 (extended protruding length from the film end surface 12) is the adhesive layer formed by the cover film 20 ( From the viewpoint of securing the protective function of 30), it is preferably 0.1 mm or more, more preferably 0.5 mm or more, further preferably 1 mm or more, and particularly preferably 1.5 mm or more. From the viewpoint of efficient production of the adhesive layer (X) with a cover film, the extended protrusion length is preferably 100 mm or less, more preferably 50 mm or less, and still more preferably 30 mm or less.

2 to 4, in the cover film-attached adhesive layer Let the distance between the outer edges in the direction D be the edge length L. The edge length L includes the above-described extended protruding length of the extended protruding end portion 20A. From the viewpoint of ensuring the protection function of the adhesive layer 30 by the cover film 20, this edge length L is preferably 0.1 mm or more, more preferably 0.5 mm or more, and still more preferably 1 mm or more, Particularly preferably, it is 1.5 mm or more. From the viewpoint of efficient production of the adhesive layer (X) with a cover film, the edge length L is preferably 100 mm or less, more preferably 50 mm or less, and further preferably 30 mm or less.

In this embodiment, the cover film 20 has a half-cut groove 22 along the end surface 32 of the adhesive layer 30 on the peeling surface 21 side. The half-cut groove 22 has a depth in the thickness direction (H). As shown in FIG. 2, the half-cut groove 22 has an inner wall surface 22a (first inner wall surface), an inner wall surface 22b (second inner wall surface), and a round bottom 22c. The inner wall surface 22a is disposed inside the half-cut groove 22 in the surface direction D (on the adhesive layer 30 side). The inner wall surface 22a is flush with the end surface 32 of the adhesive layer 30. The inner wall surface 22b is disposed outside the half-cut groove 22 in the surface direction D. The inner wall surface 22b is separated from the inner wall surface 22a in the surface direction D, and faces the inner wall surface 22a in the surface direction D. The round bottom 22c is disposed between the inner wall surfaces 22a and 22b in the surface direction D. In a cross section (FIG. 2) perpendicular to the direction of extension of the half-cut groove 22 extending along the cross section 32 in plan view, the round bottom 22c has a bulging curved shape, for example, 1 μm. It has a radius of curvature of more than

The edge width W of the edge representing the edge of the cover film 10 in plan view is preferably 10 μm or more, more preferably 15 μm or more, further preferably 20 μm or more, particularly preferably 25 μm or more (edge width In this embodiment, W is the inner edge of the protruding portion 13 of the cover film 10 in the plane direction D, and the plane direction D of the half-cut groove 22 of the cover film 20. (is the distance between the outer ends). The configuration regarding the edge width W uses an area of the edge width W (in this embodiment, an area between the inner end of the protruding portion 13 and the outer end of the half-cut groove 22) as an alignment mark for edge detection. When used, it is preferable for appropriately detecting the mark with a detection camera, and also for measuring the dimensions of the adhesive layer (X) with a cover film with high precision using the area of the edge width W (the area of the edge width is, This is the part that can be confirmed as a dark-colored area by the detection camera). The edge width W is preferably 300 μm or less, more preferably 250 μm or less, further preferably 200 μm or less, and particularly preferably 150 μm or less. This configuration is suitable for suppressing false detection by the detection camera when using the area of the edge width W as an alignment mark for edge detection, and also using the area of the edge width W to create an adhesive layer with a cover film ( This is desirable for suppressing measurement errors when measuring dimensions of X). When the cover film 10 does not have the protruding portion 13, the edge width W is equal to the inner edge in the plane direction D of the film cross section 12 of the cover film 10 and the edge width of the cover film 20. It may be the distance between the outer ends of the half-cut grooves 22 in the surface direction D. When the cover film 20 does not have the half-cut groove 22, the edge width W is the inner edge of the protruding portion 13 of the cover film 10 in the plane direction D and the pressure-sensitive adhesive layer 30. It may be the distance between the outer ends of the cross section 32 in the plane direction D. When the cover film 10 does not have the protruding portion 13 and the cover film 20 does not have the half-cut groove 22, the edge width W is that of the film cross section 12 of the cover film 10. It may be the distance between the inner edge in the surface direction D and the outer edge in the surface direction D of the cross section 32 of the adhesive layer 30.

The difference between the maximum and minimum edge width W is preferably 10 μm or less, more preferably 7 μm or less, further preferably 5 μm or less, and particularly preferably 3 μm or less. This configuration is suitable for appropriately detecting the mark with a detection camera when using the area of the edge width W as an alignment mark for edge detection, and also uses the area of the edge width W to create an adhesive layer with a cover film (X ) is desirable for measuring dimensions with high precision. The difference between the maximum and minimum values of the edge width W is the difference between the maximum and minimum values of the edge width W within a range of 1 mm of the circumferential length (cutting length) of the cover film 10 in plan view. The method of measuring the difference between the maximum and minimum edge width W is specifically as described later in the examples.

The adhesive layer 30 is formed of an adhesive composition. The adhesive composition contains a base polymer. The base polymer is an adhesive component that develops adhesiveness. Examples of base polymers include acrylic polymer, polyurethane polymer, polyamide polymer, and polyvinyl ether polymer. The base polymer may be used individually, or two or more types may be used together. From the viewpoint of ensuring good transparency and adhesion in the adhesive layer 30, an acrylic polymer is preferably used as the base polymer.

Acrylic polymer is a copolymer of a monomer component containing (meth)acrylic acid ester in a proportion of 50% by mass or more. “(meth)acrylic” means acrylic and/or methacryl. As the (meth)acrylic acid ester, an alkyl (meth)acrylic acid ester is preferably used, and more preferably, an alkyl (meth)acrylic acid ester with an alkyl group having 1 to 20 carbon atoms is used.

Examples of alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, pentyl (meth)acrylate, n-hexyl (meth)acrylate, and (meth)acrylic acid. Heptyl, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, (meth) Examples include isodecyl acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (i.e., lauryl (meth)acrylate), isotridecyl (meth)acrylate, and tetradecyl (meth)acrylate. The (meth)acrylic acid alkyl ester is preferably at least one selected from the group consisting of 2-ethylhexyl acrylate (2EHA), lauryl acrylate (LA), and n-butyl acrylate. The proportion of (meth)acrylic acid alkyl ester in the monomer component is preferably 50% by mass or more, more preferably 70% by mass or more from the viewpoint of appropriately expressing basic properties such as adhesiveness in the adhesive layer 30. , more preferably 90% by mass or more, and for example, 99% by mass or less.

The monomer component may include a copolymerizable monomer that can be copolymerized with (meth)acrylic acid alkyl ester. Examples of copolymerizable monomers include monomers having a polar group. Examples of polar group-containing monomers include hydroxy group-containing monomers, carboxyl group-containing monomers, and monomers having a nitrogen atom-containing ring. The polar group-containing monomer is helpful in modifying the acrylic polymer, such as introducing crosslinking points into the acrylic polymer and securing the cohesion of the acrylic polymer.

Examples of hydroxy group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. As the hydroxy group-containing monomer, at least one selected from the group consisting of 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate is preferably used. The proportion of the hydroxy group-containing monomer in the monomer component is preferably 1% by mass or more, more preferably 1% by mass or more, from the viewpoint of introducing a crosslinked structure into the acrylic polymer and ensuring cohesion in the adhesive layer 30. is 2% by mass or more, more preferably 3% by mass or more. The ratio is preferably 20% by mass or less, more preferably 10% by mass, from the viewpoint of adjusting the polarity of the acrylic polymer (related to the compatibility of the acrylic polymer with various additive components in the adhesive layer 30). It is as follows.

As monomers having a nitrogen atom-containing ring, for example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinyl Examples include piperazine, N-vinylpyrrole, N-vinylimidazole, and N-(meth)acryloyl-2-pyrrolidone. As the monomer having a nitrogen atom-containing ring, N-vinyl-2-pyrrolidone is preferably used. The ratio of the monomer having a nitrogen atom-containing ring in the monomer component is determined from the viewpoint of ensuring cohesion in the adhesive layer 30 and ensuring adhesion of the adhesive layer 30 to the adherend, Preferably it is 0.1 mass% or more, more preferably 0.5 mass% or more, and even more preferably 1 mass% or more. The ratio is preferably 30 mass from the viewpoint of adjustment of the glass transition temperature of the acrylic polymer and adjustment of the polarity of the acrylic polymer (related to the compatibility of the various additive components and the acrylic polymer in the adhesive layer 30). % or less, more preferably 20 mass% or less.

The base polymer preferably has a crosslinked structure. As a method of introducing a crosslinked structure into the base polymer, a base polymer having a functional group capable of reacting with the crosslinking agent and a crosslinking agent are blended into an adhesive composition and the base polymer and the crosslinking agent are reacted in an adhesive layer (first method), and the base polymer is A method (second method) is provided in which a polyfunctional monomer as a cross-linking agent is included in the monomer component to be formed, and a base polymer in which a branched structure (cross-linked structure) is introduced into the polymer chain is formed by polymerization of the monomer component. These methods may be used together.

Examples of the crosslinking agent used in the first method include compounds that react with functional groups (such as hydroxy groups and carboxyl groups) contained in the base polymer. Examples of such crosslinking agents include isocyanate crosslinking agents, peroxide crosslinking agents, and epoxy crosslinking agents. The crosslinking agent may be used individually, or two or more types may be used together.

In the second method, the monomer component (including a polyfunctional monomer for introducing a crosslinked structure and other monomers) may be polymerized at once or in multiple steps. In the multi-step polymerization method, first, monofunctional monomers to form a base polymer are polymerized (prepolymerization), thereby preparing a prepolymer composition containing a partially polymerized product (a mixture of a polymer with a low degree of polymerization and an unreacted monomer). . Next, a polyfunctional monomer as a crosslinking agent is added to the prepolymer composition, and then the partially polymerized product and the polyfunctional monomer are polymerized (main polymerization). Examples of polyfunctional monomers include polyfunctional (meth)acrylates containing two or more ethylenically unsaturated double bonds per molecule. As the polyfunctional monomer, polyfunctional acrylate is preferable from the viewpoint of being able to introduce a crosslinked structure by active energy ray polymerization (photopolymerization). Examples of multifunctional (meth)acrylates include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate. , trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. As the multifunctional (meth)acrylate, dipentaerythritol hexaacrylate (DPHA) is preferably used.

Acrylic polymer can be formed by polymerizing the monomer components described above. Examples of polymerization methods include solution polymerization, solvent-free photopolymerization (for example, UV polymerization), bulk polymerization, and emulsion polymerization. As solvents for solution polymerization, for example, ethyl acetate and toluene are used. In addition, as the polymerization initiator, for example, a thermal polymerization initiator and a photopolymerization initiator are used.

The weight average molecular weight of the base polymer is preferably 100,000 or more, more preferably 300,000 or more, and still more preferably 500,000 or more from the viewpoint of ensuring cohesion in the adhesive layer 30. The weight average molecular weight is preferably 5 million or less, more preferably 3 million or less, and even more preferably 2 million or less. The weight average molecular weight of the base polymer is measured by gel permeation chromatography (GPC) and calculated by polystyrene conversion.

From the viewpoint of ensuring the flexibility of the adhesive layer 30, the glass transition temperature (Tg) of the base polymer is preferably 0°C or lower, more preferably -10°C or lower, and even more preferably -20°C or lower. The glass transition temperature is, for example, -80°C or higher.

For the glass transition temperature (Tg) of the base polymer, the glass transition temperature (theoretical value) determined based on Fox's equation below can be used. Fox's equation is a relationship between the glass transition temperature Tg of the polymer and the glass transition temperature Tgi of the homopolymer monomer constituting the polymer. In the formula of Fox below, Tg represents the glass transition temperature (°C) of the polymer, Wi represents the weight fraction of monomer i constituting the polymer, and Tgi represents the glass transition temperature of the homopolymer formed from monomer i. (°C). Literature values can be used for the glass transition temperature of homopolymers. For example, “Polymer Handbook” (4th edition, John Wiley & Sons, Inc., 1999) and “New Polymer Bunko 7 Introduction to Synthetic Resins for Paints” (Kyojo Kitaoka, Polymer Publishing Society, 1995) ), the glass transition temperature of various homopolymers is illustrated. On the other hand, the glass transition temperature of the monomer homopolymer can also be determined by the method specifically described in Japanese Patent Application Laid-Open No. 2007-51271.

Fox's equation 1/(273+Tg)=Σ[Wi/(273+Tgi)]

The adhesive composition may contain other components as needed. Other components include, for example, solvents, silane coupling agents, ultraviolet absorbers, tackifiers, softeners, and antioxidants. Examples of the solvent include a polymerization solvent used as needed during polymerization of acrylic polymer, and a solvent added to the polymerization reaction solution after polymerization. As the solvent, for example, ethyl acetate and toluene are used.

The haze of the adhesive layer 30 is preferably 3% or less, more preferably 2% or less, and still more preferably 1% or less. The haze of the adhesive layer 30 can be measured using a haze meter based on JIS K7136 (2000). Examples of the haze meter include "NDH2000" manufactured by Nippon Denshoku Industries, Ltd., and "HM-150 Type" manufactured by Murakami Color Research Institute.

The adhesive layer (X) with a cover film can be manufactured, for example, as follows.

First, as shown in Fig. 5A, a long laminated sheet Z is produced (laminated sheet production process). The laminated sheet Z is provided with a long cover film 102, an adhesive layer 103, and a long cover film 101 in this order in the thickness direction (H). The laminated sheet Z is, for example, formed by applying the above-described adhesive composition onto the cover film 102 to form a coating film, bonding the cover film 101 onto the coating film, and forming the coating film. It can be manufactured by drying and, if necessary, irradiating with light. Application methods of the adhesive composition include, for example, roll coating, kiss roll coating, gravure coating, reverse coating, roll brush, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, and die coating. The drying temperature of the coating film is, for example, 50°C to 200°C. Drying time is, for example, 5 seconds to 20 minutes.

Next, as shown in FIG. 5B, the adhesive layer 103 on the cover film 102 is subjected to laser processing to form the adhesive layer 30 having a predetermined plan view shape (first external shape processing step). Specifically, laser light is irradiated from the cover film 101 side in the thickness direction (H) to the laminated sheet Z along the line along which the laminated sheet Z is to be cut, thereby forming a layer on the cover film 102. The adhesive layer 103 and the cover film 101 are cut. As a result, in the adhesive layer 103, the adhesive layer 30 having a predetermined plan view shape is formed, and a peripheral portion 103a (first peripheral portion) is formed around the adhesive layer 30, and a cover film is formed. In (101), the cover film 10 is formed, and a peripheral portion 101a (second peripheral portion) is formed around the cover film 10.

Examples of laser light for laser processing include gas lasers, solid-state lasers, and semiconductor lasers. Examples of gas lasers include excimer lasers and CO ₂ lasers (9.4 μm) (the numbers in parentheses indicate the wavelength of the laser light; the same applies hereinafter for lasers). Examples of excimer lasers include F ₂ excimer laser (157 nm), ArF excimer laser (193 nm), KrF excimer laser (248 nm), and XeCl excimer laser (308 nm). As a solid-state laser, for example, Nd:YAG laser (1064nm), second harmonic of Nd:YAG laser (532nm), third harmonic of Nd:YAG laser (355nm), and fourth harmonic of Nd:YAG laser ( 266nm). Examples of the semiconductor laser include a semiconductor laser with a wavelength of 405 nm. In laser processing, the pulse width of the irradiated laser light is, for example, 0.5 to 50 μsec, the pulse frequency is, for example, 1 to 200 kHz, the laser output is, for example, 2 to 250 W, and the beam spot diameter of the laser light is, for example, For example, 50 to 500 μm.

As described above, the angle α formed by the film cross section 12 of the first surface 11 of the cover film 10 formed in this process is preferably 40° or more, more preferably 45° or more. , more preferably 48° or more, further preferably 85° or less, more preferably 80° or less, and still more preferably 75° or less. As a method of adjusting the angle α, for example, adjustment of the laser irradiation conditions in laser processing can be mentioned. Laser irradiation conditions include, for example, the pulse width of the laser light, the pulse frequency, the laser output, and the beam spot diameter of the laser light.

Next, as shown in FIG. 5C, the peripheral portions 101a and 103a (FIG. 5B) are removed from the cover film 102 (removal process).

Next, as shown in FIG. 5D, the long cover film 102 is cut into a sheet-shaped cover film 20 (second external shape processing process). Examples of cutting methods include cutting by irradiation of a laser beam and cutting by punching.

As described above, the adhesive layer (X) with a cover film can be manufactured.

The adhesive layer (X) with a cover film may be an adhesive sheet with a double-sided release liner. Specifically, the adhesive layer (X) with a cover film may be a release liner in which the adhesive layer 30 is a long adhesive sheet and the cover film 10 is in peelable contact with the adhesive sheet. In that case, the first surface 11 of the cover film 10 is preferably a peeling surface that has been subjected to a peeling treatment. In such an adhesive layer (X) with a cover film, the cover films (10, 20) are peeled off from the adhesive layer (30) when using the adhesive layer (30) as an adhesive sheet.

Example

The present invention will be described in detail below by way of examples. However, the present invention is not limited to the examples. In addition, the specific values of the mixing amount (content), physical properties, and parameters described below are the corresponding mixing amounts (content), physical properties, and parameters described in the above-mentioned "Specific Details for Carrying out the Invention." It can be replaced with an upper limit (a numerical value defined as “less than” or “less than”) or a lower limit (a numerical value defined as “above” or “more than”).

[Example 1]

<Preparation of adhesive composition>

First, 50 parts by mass of 2-ethylhexyl acrylate (2EHA), 40 parts by mass of lauryl acrylate (LA), 2 parts by mass of n-butyl acrylate (BA), and 6 parts by mass of 4-hydroxybutyl acrylate (4HBA). 2 parts by mass of N-vinyl-2-pyrrolidone (NVP), and 0.015 parts by mass of a photopolymerization initiator (product name "Omnirad 184", manufactured by IGM Resins) is irradiated with ultraviolet rays (polymerization reaction), A prepolymer composition (polymerization rate of about 10%) was obtained (the prepolymer composition contains a monomer component that has not undergone a polymerization reaction). Next, 100 parts by mass of the prepolymer composition, 0.08 parts by mass of dipentaerythritol hexaacrylate (DPHA) as a multifunctional acrylate monomer, and a silane coupling agent (product name "KBM-403", 3-glycidoxypropyltri) 0.3 parts by mass of methoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed to obtain adhesive composition C1.

<Production of release liner>

First, a 28.5% by mass toluene solution of a silicone-based release treatment agent (product name “KE-3703”) containing a polyorganosiloxane having a hexenyl group in the molecule and a polyorganosiloxane crosslinking agent having a hydrosilyl group in the molecule. 90 parts by mass of a silicone-based peeling control agent (product name "KS-3800", manufactured by Shin-Etsu Chemical Co., Ltd.), 0.9 parts by mass of a platinum catalyst for silicone curing (product name "CAT-PL-50T", 0.3 parts by mass of (manufactured by Shin-Etsu Kogyo Chemical Co., Ltd.) and a solvent were mixed to prepare a release treatment agent solution with a silicon solid content concentration of 0.7% by mass. The solvent is a mixed solvent of toluene and hexane in a volume ratio of 1:1. Next, a biaxially stretched polyester film (product name “Lumiror XD500P”, thickness 75 μm, manufactured by Toray Advanced Materials Korea) was subjected to peeling treatment. Specifically, first, the above-described release treatment solution was applied to one side of the polyester film to form a coating film. For application, wire bar #9 was used. Next, the coating film on the film was dried by heating at 130°C for 1 minute using a hot air dryer. From this, a silicone release layer with a thickness of 0.1 μm was formed on the polyester film (release treatment). As described above, a release liner having a release treatment surface on one side was produced.

<Production of laminated sheets>

First, pressure-sensitive adhesive composition C1 was applied on the peel-treated surface of the release liner (second cover film) described above to form a coating film. Next, the plasma-treated side of the surface protection film (first cover film), one side of which was plasma-treated, was bonded to the coating film on the release liner. The surface protection film is a transparent polyimide (PI) film with a thickness of 49 μm. In the plasma treatment, a plasma irradiation device (product name "AP-TO5", manufactured by Sekisui Industries, Ltd.) was used, the voltage was set to 160 V, the frequency was set to 10 kHz, and the processing speed was set to 5000 mm/min. Next, the coating film was irradiated with ultraviolet rays from the surface protection film side to cure the coating film with ultraviolet rays, thereby forming an adhesive layer (adhesive A1) with a thickness of 25 μm. As a result, a laminated sheet (release liner/adhesive layer/surface protection film) as a raw material sheet for the adhesive layer with a cover film was obtained. In ultraviolet irradiation, a black light was used as the irradiation light source, and the irradiation intensity was set to 5 mW/cm ² (the same applies to ultraviolet irradiation described later).

<First external processing>

Next, the adhesive layer of the laminated sheet was externally processed (first external shape processing process). Specifically, the adhesive layer and surface on the release liner are protected by irradiating CO ₂ laser light (wavelength 9.4 μm) to the laminated sheet in the thickness direction from the surface protection film side along the first cutting line of the laminated sheet. The film was cut in the thickness direction (laser processing). In laser irradiation, the first laser processing device (product name "LC500", manufactured by Takei Electric Industries) was used, the pulse width of the irradiated laser light was set to 3.3 μsec, the laser output was set to 23 W, and the pulse frequency was set to 15 kHz. In this process, in the adhesive layer, the adhesive layer and the first peripheral portion thereof having a predetermined plan view shape are created, and in the surface protection film, a second peripheral portion is created on the first peripheral portion.

<Removal of surrounding parts, second external processing>

After the first contour machining process, the first and second perimeters were removed from the release liner. After that, the release liner was externally processed (second external processing process). Specifically, the release liner was cut into a predetermined plan view shape by irradiating the release liner with a CO ₂ laser in the thickness direction along the second cutting line of the release liner. The second line to be cut is 3 mm away from the first line to be cut in the plane direction. In addition, in the laser irradiation of this process, the first laser processing device (product name "LC500", manufactured by Takei Electric Industries) is used, the pulse width of the irradiated laser light is set to 3.3 μsec, the laser output is set to 40 W, and the pulse frequency is set to 40 W. was set to 15kHz.

As described above, the adhesive layer with the cover film of Example 1 (surface protection film/adhesive layer/release liner) was produced. The adhesive layer with a cover film of Example 1 includes a surface protection film with an adhesive layer (thickness of 25 μm) and a release liner that covers the adhesive layer side of the film.

[Example 2]

First, 45 parts by mass of 2-ethylhexyl acrylate (2EHA), 42 parts by mass of lauryl acrylate (LA), 2 parts by mass of n-butyl acrylate (BA), and 4 parts by mass of 4-hydroxybutyl acrylate (4HBA). 2 parts by mass, 7 parts by mass of N-vinyl-2-pyrrolidone (NVP), and 0.015 parts by mass of a photopolymerization initiator (Omnirad 184) was irradiated with ultraviolet rays (polymerization reaction) to produce a prepolymer composition (polymerization rate of approximately 10%) was obtained. Next, 100 parts by mass of the prepolymer composition, 0.08 parts by mass of dipentaerythritol hexaacrylate (DPHA) as a multifunctional acrylate monomer, and a silane coupling agent (product name "KBM-403", 3-glycidoxypropyltri) 0.3 parts by mass of methoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed to obtain adhesive composition C2. Except that this adhesive composition C2 was used instead of adhesive composition C1 to form an adhesive layer (Adhesive A2) with a thickness of 15 μm, the adhesive layer with a cover film of Example 2 was prepared in the same manner as the adhesive layer with a cover film of Example 2 ( Surface protection film/adhesive layer/release liner) was produced.

[Example 3]

The adhesive layer with a cover film of Example 3 was produced in the same manner as the adhesive layer with a cover film of Example 1 except for the following. In the laminated sheet manufacturing process, the thickness of the adhesive layer to be formed was set to 15 μm. In the first external shape processing process, the pulse frequency of the irradiated laser light was set to 30 kHz.

[Example 4]

The adhesive layer with a cover film of Example 4 was produced in the same manner as the adhesive layer with a cover film of Example 1 except for the following. In the first external shape processing process, a second laser processing device (product name “LC750”, manufactured by Takei Electric Industries) is used instead of the first laser processing device, the pulse width of the irradiated laser light is set to 0.83 μsec, and the pulse frequency is set to 0.83 μsec. The frequency was set to 30kHz, and the laser output was set to 23W.

[Example 5]

The adhesive layer with a cover film of Example 5 was produced in the same manner as the adhesive layer with a cover film of Example 1 except for the following. In the first external shape processing process, the pulse frequency of the irradiated laser light was set to 30 kHz.

[Example 6]

The adhesive layer with a cover film of Example 6 was produced in the same manner as the adhesive layer with a cover film of Example 1 except for the following. In the first outer shape processing process, the pulse frequency of the irradiated laser light was set to 5 kHz.

[Comparative Example 1]

The adhesive layer with a cover film of Comparative Example 1 was produced in the same manner as the adhesive layer with a cover film of Example 1 except for the following. In the laminated sheet manufacturing process, the thickness of the adhesive layer to be formed was set to 15 μm. In the first external shape processing process, press processing was performed instead of laser processing. Specifically, the first press processing blade was driven into the adhesive layer on the release liner in the thickness direction from the surface protection film side until it reached the release liner, thereby forming an adhesive layer having a predetermined plan view shape. The first press processing blade has a blade tip with a blade angle of 80 degrees.

[Comparative Example 2]

The adhesive layer with a cover film of Comparative Example 2 was produced in the same manner as the adhesive layer with a cover film of Example 2 except for the following. In the first external shape processing process, press processing was performed instead of laser processing. Specifically, a second press processing blade was driven into the adhesive layer on the release liner in the thickness direction from the surface protection film side until it reached the release liner, thereby forming an adhesive layer having a predetermined plan view shape. The second press processing blade has a blade tip with a blade angle of 30 degrees.

[Comparative Example 3]

The adhesive layer with a cover film of Comparative Example 3 was produced in the same manner as the adhesive layer with a cover film of Example 1 except for the following. In the laminated sheet manufacturing process, the thickness of the adhesive layer to be formed was set to 15 μm. In the first external shape processing process, press processing was performed instead of laser processing. Specifically, the second press processing blade (having a blade tip with a blade angle of 30 degrees) is driven into the adhesive layer on the release liner in the thickness direction from the surface protection film side until it reaches the release liner, thereby forming a predetermined planar view. A shaped adhesive layer was formed.

<Gel fraction>

The gel fraction of each adhesive layer in Examples 1 to 6 and Comparative Examples 1 to 3 was measured. Specifically, it is as follows.

First, an adhesive sample of about 0.1 g (mass: W ₁ mg) was taken from the adhesive layer. Next, the adhesive sample was wrapped in a drawstring bag with a porous film made of tetrafluoroethylene resin (mass: W ₂ mg) with an average pore diameter of 0.2 μm, and the entrance was tied with a string (mass: W ₃ mg) to obtain a package. As a porous membrane made of tetrafluoroethylene resin, a porous membrane manufactured by Nitto Denko Co., Ltd. (product name “Nitoflon NTF1122”) was used. Next, the package containing the adhesive sample was placed in a container with a volume of 50 mL, and then the container was filled with ethyl acetate (one container was used for each package). After this was left standing at 23°C for 7 days, the package was taken out from the container and dried at 130°C for 2 hours. Afterwards, the mass (W ₄ mg) of the package was measured. Then, the gel fraction of the adhesive layer was calculated by substituting the values of W ₁ to _{W 4} into the following equation. The values are shown in Tables 1 and 2.

Gel fraction (%)=[(W ₄ -W ₂ -W ₃ )/W ₁ ]×100

<Shear storage modulus>

Dynamic viscoelasticity was measured for each adhesive layer in Examples 1 to 6 and Comparative Examples 1 to 3.

First, for each adhesive layer, the required number of samples for measurement were produced. Specifically, first, a plurality of adhesive layer pieces cut from the adhesive layer were bonded together to produce a sample sheet with a thickness of approximately 1.5 mm. Next, this sheet was punched to obtain a cylindrical pellet (diameter 7.9 mm) as a measurement sample.

Then, the dynamic viscoelasticity measurement was performed on the sample for measurement using a dynamic viscoelasticity measuring device (product name "Advanced Rheometric Expansion System (ARES)", manufactured by Rheometric Scientific). Specifically, the measurement sample was fixed to the jig of a parallel plate with a diameter of 7.9 mm in the same device, and then the measurement was performed. In this measurement, the measurement mode was set to shear mode, the measurement temperature range was -40°C to 100°C, the temperature increase rate was 5°C/min, and the frequency was 1Hz. From the measurement results, the shear storage modulus at 25°C and the maximum shear storage modulus within the measurement temperature range were read. The values are shown in Tables 1 and 2.

<Shape analysis>

The shape of each adhesive layer in Examples 1 to 6 and Comparative Examples 1 to 3 was analyzed using a shape analysis laser microscope (product name "VK-X1000", manufactured by KEYENCE). Specifically, through the same microscope, the positional deviation length d of the end of the adhesive layer (FIGS. 2 to 4), the angle α at the end of the surface protection film (first cover film) (FIGS. 2 to 4), and the adhesive The difference between the maximum and minimum values of the angle β at the end of the layer (FIGS. 2 and 4) and the edge width W of the surface protection film (FIGS. 2 to 4) was measured. The results are shown in Tables 1 and 2. The ratio of angle β to angle α (β/α) is also shown in Tables 1 and 2. The positional deviation length d is a length in a direction perpendicular to the film cross-section (film cross-section 12 in FIGS. 2 to 4) and the extension surface of the film cross-section (extension surface 12' in FIGS. 2 to 4). . In addition, the difference between the maximum value and the minimum value of the edge width W is the difference between the maximum value and the minimum value of the edge width W within the range of 1 mm of the circumferential length (cutting length) of the surface protection film in plan view.

<End blocking>

The difficulty of end blocking was investigated for each cover film-attached adhesive layer of Examples 1 to 6 and Comparative Examples 1 to 3. Specifically, first, 10 evaluation samples of substantially the same size were produced for each adhesive layer with a cover film, and the 10 evaluation samples were stacked to form a film bundle (first step). Next, the tip adhesive surface of a cylindrical rod (diameter 10 mm) having an adhesive surface at the tip is forced from above against the adhesive layer with a cover film located at the top of the film bundle, and then the rod is pulled upward. , the number of sheets of the adhesive layer with the cover film that rose along the rod was counted (second process). The trials consisting of the first process and the subsequent second process were performed 10 times for each film bundle. In 10 trials, the number of trials in which there was only one cover film-attached adhesive layer rising along with the rod was evaluated as "good" if the number was 10, if it was 6 to 9, it was evaluated as "positive", and if it was 5 or less, it was evaluated as "good". The case was evaluated as “poor.” The evaluation results are shown in Table 1.

<Pool contamination>

With respect to each cover film-attached adhesive layer of Examples 1 to 6 and Comparative Examples 1 to 3, the presence/absence and degree of glue contamination were investigated as follows.

First, 50 sheets of sample film (100 mm x 50 mm) were cut out from the adhesive layer with the cover film using a cutting machine. Next, the cut cross section of each sample film was observed with the naked eye and an optical microscope. Then, the ratio (%) of the number of sample films (glue-contaminated films) in which glue contamination occurred in the cut cross section to the total number of sample films (50) was calculated. Full contamination refers to a state in which the adhesive pushed out from the adhesive layer has adhered to the outer surface of the cover film (surface protection film, release liner). Regarding the suppression of pool contamination, the case where the ratio of the pool contamination film is less than 10% is evaluated as “good”, and the case where the percentage of the pool contamination film is 10% or more but less than 20% is evaluated as “positive”, and the case where the percentage of the pool contamination film is less than 10% is evaluated as “good”. Cases where the film ratio was more than 20% were evaluated as “defective.” These results are shown in Tables 1 and 2.

X Cover film attachment adhesive layer
Y Adhesive layer attached surface protection film
H Thickness direction
D-plane direction
10 Cover film (first cover film)
11 Page 1
12 Film Cross Section
12' extension side
20 Cover film (second cover film)
20A extended protruding end
21 Peeling surface
22 Half Cut Home
30 Adhesive layer
30A end
31 Adhesive side
32 section

Claims (6)

An adhesive layer with a cover film comprising a first cover film, an adhesive layer, and a second cover film in this order in the thickness direction,
The first cover film has a first surface on the side of the adhesive layer and has a film cross-section forming an acute angle with the first surface,
The second cover film has an extended protruding end, and the extended protruding end protrudes outward from the end of the adhesive layer in a plane direction perpendicular to the thickness direction,
A pressure-sensitive adhesive layer with a cover film, wherein a displacement length of the end portion of the pressure-sensitive adhesive layer from the cross-section of the film and the extended surface of the cross-section of the film is 5 μm or less. According to claim 1,
An adhesive layer with a cover film, wherein the gel fraction of the adhesive layer is 80% or less. According to claim 1,
An adhesive layer with a cover film, wherein the adhesive layer has a thickness of 5 μm or more and 50 μm or less. According to claim 1,
An adhesive layer with a cover film, wherein the acute angle in the first cover film is 40° or more and 85° or less. According to claim 4,
The pressure-sensitive adhesive layer has an adhesive surface on a side of the second cover film, and has a cross-section of the pressure-sensitive adhesive layer forming an acute angle with the adhesive surface, and the pressure-sensitive adhesive layer has a cross-section of the pressure-sensitive adhesive layer at an acute angle, An adhesive layer with a cover film where the ratio of the acute angles is 0.9 or more and 1.5 or less. The method according to any one of claims 1 to 5,
An adhesive layer with a cover film, wherein the difference between the maximum and minimum edge widths of the edge representing the edge of the first cover film in plan view is 10 μm or less.