JP7287170B2 - Adhesive sheet - Google Patents

Description

The present invention relates to an adhesive sheet.

In recent years, as a pressure-sensitive adhesive sheet that is used by being attached to a smooth adherend such as a window glass, a support layer and a resin layer formed of a resin having adhesiveness and formed on at least one side in the thickness direction of the support layer have been developed. A laminate comprising: Such adhesive sheets include, for example, functional films for window glass that are excellent in heat shielding and heat insulating properties; transparent screens; architectural decorative materials such as wallpaper and other interior decoration materials; posters, stickers, and labels Adhesive materials for advertising such as; The surface of the support layer of the pressure-sensitive adhesive sheet described above is decorated with printing or the like depending on the application.

Here, when the above-mentioned pressure-sensitive adhesive sheet is attached, gas (usually air) does not remain at the interface between the resin layer of the pressure-sensitive adhesive sheet and the adherend, and escapes from the peripheral edge of the pressure-sensitive adhesive sheet. Adheres well to the adherend. Therefore, the pressure-sensitive adhesive sheet is required to be easy to escape gas when attached, that is, to be excellent in "air release property".

For example, in Patent Document 1, in a pressure-sensitive adhesive label having a pressure-sensitive adhesive layer on the surface of a substrate sheet, the pressure-sensitive adhesive layer has recesses whose bottom portions reach the surface of the substrate sheet and whose both ends are opened at the edges of the label. It has been reported that providing a plurality of spaced grooves makes it easier for air to escape when the pressure-sensitive adhesive label is attached to an adherend.

JP-A-2002-91317

However, the pressure-sensitive adhesive sheet of the above-described prior art is improved in that, when used in applications requiring transparency, such as functional films for window glass and transparent screens, it satisfactorily achieves both air release properties and transparency. There was room for

Accordingly, an object of the present invention is to provide a pressure-sensitive adhesive sheet that can satisfactorily achieve both air release property and transparency.

The inventor of the present invention has made intensive studies with the aim of solving the above problems. Further, the present inventors have provided a support layer and a predetermined resin layer formed on at least one side in the thickness direction of the support layer, and a plurality of grooves are formed on the surface of the resin layer under predetermined conditions. The inventors have found that a pressure-sensitive adhesive sheet can satisfactorily achieve both air release property and transparency, and completed the present invention.

That is, an object of the present invention is to advantageously solve the above problems, and a pressure-sensitive adhesive sheet of the present invention comprises a support layer and a resin formed on at least one side of the support layer in the thickness direction. layer, wherein a plurality of grooves having a depth of 0.5 μm or more and less than 10 μm are formed on the surface of the resin layer, and the grooves are not parallel to the surface direction of the resin layer. When the surface of the resin layer is projected in the thickness direction of the resin layer with respect to a plane having a wall surface S and parallel to the resin layer, the inner wall surface S occupies the projected area of the entire surface of the resin layer. is 10% or less, and the storage elastic modulus of the resin layer is 7.0×10 ⁵ Pa or more and 1.0×10 ⁹ Pa or less. Thus, the support layer and the resin layer having the predetermined storage elastic modulus formed on at least one side in the thickness direction of the support layer are provided, and the depth of the predetermined range is provided on the surface of the resin layer. a plurality of grooves are formed, the grooves have an inner wall surface S that is not parallel to the surface direction of the resin layer, and the ratio of the projected area of the inner wall surface S to the projected area of the entire surface of the resin layer is equal to or less than the above predetermined value The pressure-sensitive adhesive sheet can satisfactorily achieve both air release property and transparency.
When the surface of the resin layer is projected in the thickness direction of the resin layer with respect to a plane parallel to the resin layer, the ratio of the projected area of the inner wall surface S of the groove to the projected area of the entire surface of the resin layer is , the shape, size and pitch of the grooves formed in the resin layer, the area of the surface of the resin layer, and the like.
Moreover, the storage elastic modulus of the resin layer can be measured by the method described in the examples of the present specification.

Here, in the adhesive sheet of the present invention, the groove depth is preferably less than 5 μm. Thus, if the groove depth is less than the predetermined value, the transparency of the pressure-sensitive adhesive sheet can be further enhanced.

Further, in the pressure-sensitive adhesive sheet of the present invention, it is preferable that the opening width of the groove is larger than the depth of the groove. Thus, if the opening width of the groove is larger than the depth of the groove, the air release property of the adhesive sheet can be further enhanced.

Furthermore, in the pressure-sensitive adhesive sheet of the present invention, it is preferable that a plurality of grooves are formed in a row. Thus, if a plurality of grooves are formed in a row, the air release property of the adhesive sheet can be further enhanced.

Further, in the pressure-sensitive adhesive sheet of the present invention, it is preferable that the plurality of grooves formed in a row have a pitch of less than 1000 μm. Thus, if the pitch of the grooves is less than the predetermined value, the air release property of the adhesive sheet is further enhanced, and a striped pattern caused by the grooves is visually recognized on the adhesive sheet (hereinafter referred to as "stripe feeling"). ) can be suppressed.

Furthermore, in the pressure-sensitive adhesive sheet of the present invention, the resin layer is made of a cured product of an ultraviolet-curable resin composition containing an ultraviolet-curable resin and a curing agent, and the curing agent in the ultraviolet-curable resin composition is The content is preferably 0.5% by mass or more. In this way, the resin layer is made of a cured product of an ultraviolet curable resin composition containing an ultraviolet curable resin and a curing agent, and the content of the curing agent in the ultraviolet curable resin composition is at least the predetermined value. In this case, the air release property and transparency of the pressure-sensitive adhesive sheet can be more satisfactorily compatible.

Further, in the pressure-sensitive adhesive sheet of the present invention, it is preferable that the standard deviation of the pitch of the plurality of grooves formed in rows is 1 μm or more. Thus, if the standard deviation of the pitch of the plurality of grooves formed in a row is equal to or greater than the predetermined value, it is possible to suppress the "iris phenomenon" in which a rainbow pattern is observed on the adhesive sheet due to the diffraction of light. can.

Furthermore, in the pressure-sensitive adhesive sheet of the present invention, it is preferable that the standard deviation of the opening width of the plurality of grooves is 0.5 μm or more. Thus, if the standard deviation of the opening widths of the plurality of grooves is equal to or greater than the predetermined value, the iris phenomenon in the adhesive sheet can be suppressed.

Further, in the pressure-sensitive adhesive sheet of the present invention, it is preferable that the standard deviation of the depth of the plurality of grooves is 0.5 μm or more. Thus, if the standard deviation of the depths of the plurality of grooves is equal to or greater than the predetermined value, the iris phenomenon in the adhesive sheet can be suppressed.

Further, in the pressure-sensitive adhesive sheet of the present invention, the standard deviation of cross-sectional areas in the width direction of the plurality of grooves is preferably 3% or more of the average cross-sectional area of the width of the grooves. Thus, if the standard deviation of cross-sectional areas (areas of cross-sectional shapes) of the plurality of grooves in the transverse direction is equal to or greater than the predetermined value, the iris phenomenon in the adhesive sheet can be suppressed.

Further, in the pressure-sensitive adhesive sheet of the present invention, the inclination angle of the inner wall surface S with respect to the surface direction of the resin layer is preferably more than 0° and less than 90°. If the inclination angle of the inner wall surface S with respect to the surface direction of the resin layer is more than 0° and less than 90°, the air release property of the adhesive sheet can be further enhanced.

Furthermore, in the pressure-sensitive adhesive sheet of the present invention, it is preferable that the groove does not have an inner wall surface P parallel to the surface direction of the resin layer. Thus, if the groove does not have an inner wall surface P parallel to the surface direction of the resin layer, the iris phenomenon in the adhesive sheet can be suppressed.

Further, in the pressure-sensitive adhesive sheet of the present invention, it is preferable that the cross-sectional shape of the groove in the width direction is triangular. Thus, if the cross-sectional shape of the groove in the width direction is triangular, the iris phenomenon in the adhesive sheet can be suppressed.

According to the present invention, it is possible to provide a pressure-sensitive adhesive sheet that satisfactorily achieves both air release property and transparency.

1 is a plan view of an example of the pressure-sensitive adhesive sheet of the present invention; FIG. 1 is a cross-sectional view of an example of the pressure-sensitive adhesive sheet of the present invention; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.

(adhesive sheet)
The pressure-sensitive adhesive sheet of the present invention comprises a support layer and a predetermined resin layer formed on at least one side in the thickness direction of the support layer, and a plurality of grooves are formed on the surface of the resin layer under predetermined conditions. It is characterized by Here, the pressure-sensitive adhesive sheet of the present invention can be used by attaching it to a smooth adherend such as a window glass. Further, the pressure-sensitive adhesive sheet of the present invention can satisfactorily achieve both air release property and transparency when used by being attached to a smooth adherend such as a window glass. Moreover, the pressure-sensitive adhesive sheet of the present invention can be easily peeled off and re-applied even after being applied to a smooth adherend. That is, the pressure-sensitive adhesive sheet of the present invention is also excellent in reworkability.
Therefore, the pressure-sensitive adhesive sheet of the present invention can be used for functional films for window glass; transparent screens; architectural decorative materials such as interior decoration materials such as wallpaper; It can be used suitably for the application.
The pressure-sensitive adhesive sheet of the present invention may have members other than the above-described support layer and resin layer as long as the desired effects of the present invention can be obtained. For example, the pressure-sensitive adhesive sheet of the present invention may have a layer other than the above-described support layer and resin layer between the support layer and the resin layer as long as the desired effect of the present invention can be obtained. .

<Support layer>
The pressure-sensitive adhesive sheet of the present invention has a support layer. The material constituting the support layer is not particularly limited as long as the support layer can support the resin layer described later. Materials constituting the support include, for example, polyester resins such as polyethylene terephthalate (PET); polystyrene resins; cyclic polyolefin resins; polyvinyl chloride resins; acrylic resins; polycarbonate resins; A fluororesin is mentioned. One of these resins may be used alone, or two or more of them may be used in combination at any ratio.
In addition to the resins described above, the support layer may contain an infrared-absorbing material, an ultraviolet-absorbing material, a fluorescent material, various inorganic particles, a plasticizer, an antioxidant, and the like, as long as the desired effects of the present invention can be obtained. It may contain other ingredients.

The thickness of the support layer can be appropriately set within a range in which the desired effects of the present invention can be obtained. It is more preferably 1000 μm or less, more preferably 500 μm or less, and even more preferably 250 μm or less. When the thickness of the support layer is at least the above lower limit, the strength of the pressure-sensitive adhesive sheet can be maintained satisfactorily. On the other hand, if the thickness of the support layer is equal to or less than the above upper limit, the transparency of the pressure-sensitive adhesive sheet can be further enhanced.

Moreover, it is preferable that the support layer has excellent transparency. Specifically, the haze of the support layer is preferably 10% or less, more preferably 7% or less, and even more preferably 3% or less. If the haze of the support layer is equal to or less than the predetermined value, the transparency of the pressure-sensitive adhesive sheet can be further enhanced.
The haze of the support layer can be measured using "NDH4000" manufactured by Nippon Denshoku Co., Ltd. according to JIS K7136.

Furthermore, the surface roughness Ra of the support layer is preferably less than 100 nm.
In addition, surface roughness Ra can be measured by AFM (atomic force microscope).
Moreover, the inclination angle of the surface of the support layer with respect to the surface direction of the support layer is preferably less than 1°.

The support layer may have a single-layer structure, or may have a multi-layer structure in which two or more layers are laminated. In addition, at least one surface of the support layer in the thickness direction may be decorated with printing or the like depending on the application of the pressure-sensitive adhesive sheet and within the range where the desired effect of the present invention can be obtained.

<Resin layer>
The pressure-sensitive adhesive sheet of the present invention comprises a predetermined resin layer formed on at least one side in the thickness direction of the support layer described above. In the adhesive sheet of the present invention, a predetermined resin layer may be formed on both sides of the support layer in the thickness direction, or a predetermined resin layer may be formed on one side of the support layer. However, a predetermined resin layer is usually formed on one side of the support layer. Then, the pressure-sensitive adhesive sheet can be attached to the adherend by bringing the resin layer-formed side of the pressure-sensitive adhesive sheet into close contact with a smooth adherend such as a window glass.

<<Groove>>
Here, a plurality of grooves are formed on the surface of the resin layer. By forming a plurality of grooves on the surface of the resin layer, when the adhesive sheet is attached to a smooth adherend such as a window glass, gas (usually air) is generated at the interface between the resin layer and the adherend. ) easily escapes from the peripheral edge of the adhesive sheet through the grooves, and the resin layer and the adherend are well adhered to each other, so that the air release property of the adhesive sheet can be enhanced.

A plurality of grooves formed on the surface of the resin layer will be described in detail below with reference to the drawings.

[Planar shape of groove]
FIG. 1 is a plan view schematically showing an example of the pressure-sensitive adhesive sheet of the present invention. Note that FIG. 1 is a plan view of the pressure-sensitive adhesive sheet 100 when observed from the side on which the resin layer 10 is formed.

Like the adhesive sheet 100 shown in FIG. 1, it is preferable that a plurality of grooves 30 are formed in a row on the surface 11 of the resin layer 10 . That is, it is preferable that a plurality of linear grooves 30 are formed in parallel on the surface 11 of the resin layer 10 . If a plurality of grooves 30 are formed in a row on the surface 11 of the resin layer 10, the air release property of the adhesive sheet can be further enhanced.
Furthermore, although a plurality of grooves 30 may be formed in a row only in a partial region of the surface 11 of the resin layer 10, as in the adhesive sheet 100 shown in FIG. It is preferable that a plurality of grooves 30 are formed in a row over the entire length. If a plurality of grooves 30 are formed in a row over the entire surface 11 of the resin layer 10, the air release property of the adhesive sheet can be further enhanced.

Further, when a plurality of grooves 30 are formed in a row on the surface 11 of the resin layer 10, the pitch 32 of the grooves 30 is preferably 50 μm or more, more preferably 100 μm or more, and more preferably 150 μm or more. more preferably less than 1000 μm, more preferably less than 800 μm, even more preferably less than 600 μm. If the pitch of the grooves 30 is equal to or greater than the above lower limit, the transparency of the adhesive sheet can be further enhanced. On the other hand, if the pitch 32 of the grooves 30 is less than the above upper limit, the air release property of the adhesive sheet can be further enhanced and the striped feeling of the adhesive sheet can be suppressed.
In addition, the pitch 32 of the plurality of grooves 30 formed in a row means that, in two adjacent grooves 30A and 30B, from the edge 31A on one side in the width direction of one groove 30A to the width of the other groove 30B. It refers to the distance to the edge 31B on one side of the direction.

Furthermore, the plurality of grooves 30 may be formed in rows at the same pitch, or may be formed in rows at different pitches, but may be formed in rows at different pitches. is preferred. That is, it is preferable that the pitches of the plurality of grooves 30 formed in a row are varied. If there is variation in the pitch of the plurality of grooves 30 formed in rows, the iris phenomenon in the adhesive sheet can be suppressed.
When the pitch of the plurality of grooves 30 formed in a row has variations, the standard deviation of the pitch of the plurality of grooves 30 formed in a row is preferably 1 μm or more, and preferably 1.2 μm or more. more preferably 1.5 μm or more, and even more preferably 10 μm or less. If the standard deviation of the pitch of the plurality of grooves 30 formed in rows is equal to or greater than the above lower limit, the iris phenomenon in the adhesive sheet can be further suppressed. On the other hand, if the standard deviation of the pitch of the plurality of grooves 30 formed in rows is equal to or less than the above upper limit, the gap between the grooves does not become too large, so air release can be maintained satisfactorily.

Moreover, the groove 30 formed in the surface 11 of the resin layer 10 extends to the periphery of the surface 11 of the resin layer 10 . Since the grooves 30 extend to the periphery of the surface 11 of the resin layer 10, gas (usually air) can easily escape from the periphery of the adhesive sheet through the grooves when the adhesive sheet is attached. The air release property of the seat can be improved.
For example, at least one end of the groove 30 in the longitudinal direction (extending direction) extends to the periphery of the surface 11 of the resin layer 10 . From the viewpoint of further improving the air release property of the adhesive sheet, it is preferable that both longitudinal ends of the groove 30 extend to the periphery of the surface 11 of the resin layer 10 . As shown in the plan view of FIG. 1 , when the surface 11 of the resin layer 10 has a substantially rectangular shape, one end of the groove 30 in the longitudinal direction is one of the pair of opposite sides of the surface 11 of the resin layer 10 . , and the other end of the groove 30 in the longitudinal direction preferably extends to the periphery of the other of the pair of opposite sides.

In addition, although the example in which a plurality of grooves 30 are formed in a row on the surface 11 of the resin layer 10 has been described above, the pressure-sensitive adhesive sheet 100 of the present invention is not limited to this. For example, the shape of the groove 30 when viewed from above the surface 11 of the resin layer 10 is not particularly limited, and may be linear or curved. Also, the plurality of grooves 30 formed on the surface 11 of the resin layer 10 may or may not intersect with each other.

[Cross-sectional shape of groove]
FIG. 2 is a cross-sectional view of an example of the pressure-sensitive adhesive sheet of the invention shown in FIG. FIG. 2 is an enlarged view of a part of a cross section obtained by cutting the adhesive sheet 100 in the width direction (transverse direction) of the groove 30A.

In the adhesive sheet 100 shown in FIG. 2, the resin layer 10 is formed on one side of the support layer 20 in the thickness direction, and the surface of the resin layer 10 (that is, the surface opposite to the side on which the support layer 20 is arranged) ) are formed with a plurality of grooves 30 (grooves 30A and 30B in the illustrated example).

In the cross-sectional view of FIG. 2, the cross-sectional shape of the groove 30A in the width direction is trapezoidal. Here, the "cross-sectional shape of the groove in the width direction" refers to the cross-sectional shape in the width direction of the space surrounded by the inner wall surface of the groove 30A and the opening surface of the groove 30A. In FIG. 2, the cross-sectional shape of the groove 30A in the width direction is a trapezoid. formed by

In the cross-sectional view shown in FIG. 2, the cross-sectional shape of the groove 30A in the width direction is a trapezoid (quadrilateral), but the pressure-sensitive adhesive sheet 100 of the present invention is not limited to this, and the cross-sectional shape of the groove 30A in the width direction is For example, it may be a triangle, or a polygon with pentagons or more.

Here, from the viewpoint of suppressing the iris phenomenon in the adhesive sheet, it is preferable that the groove 30A does not have an inner wall surface P parallel to the surface direction of the resin layer 10 .

For example, in the cross-sectional view of FIG. 2, among the inner wall surfaces of the groove 30A, the lower bottom surface 34, which is the inner wall surface P parallel to the surface direction of the resin layer 10, does not exist, that is, the cross-sectional shape of the groove 30A in the width direction is A triangular shape is preferred. At this time, the triangular cross-sectional shape of the groove 30A in the width direction is formed by the upper bottom surface 33 (opening surface) of the groove 30A and two inclined surfaces (inner wall surface S35). Thus, if the groove 30A does not have the lower bottom surface 34 and the cross-sectional shape of the groove 30A in the width direction is triangular, the iris phenomenon in the adhesive sheet can be suppressed.

The cross-sectional shape of one groove 30A in the width direction may be the same or different from one end to the other end in the longitudinal direction of the groove 30A. shall be the same.

In addition, cross-sectional shapes in the width direction of the plurality of grooves 30 formed on the surface 11 of the resin layer 10 may be the same or different, but are preferably different. That is, it is preferable that the cross-sectional shapes of the plurality of grooves 30 in the width direction have variations. If there is variation in the cross-sectional shape of the plurality of grooves 30 in the width direction, the iris phenomenon in the adhesive sheet can be suppressed.

Furthermore, the cross-sectional area (sectional area) of the groove 30A in the width direction is preferably 3 μm ² or more, more preferably 5 μm ² or more, even more preferably 10 μm ² or more, and 200 μm ² or less. is preferably 100 μm ² or less, and even more preferably 60 μm ² or less. If the cross-sectional area of the groove 30A in the width direction is equal to or greater than the lower limit, the air release property of the adhesive sheet can be further enhanced. On the other hand, if the cross-sectional area of the grooves 30A in the width direction is equal to or less than the above upper limit, the transparency of the adhesive sheet can be further enhanced.

The cross-sectional area of one groove 30A in the width direction may be the same or different from one end to the other end in the longitudinal direction of the groove 30A. shall be the same.

Further, cross-sectional areas in the width direction of the plurality of grooves 30 formed on the surface 11 of the resin layer 10 may be the same or different, but are preferably different. That is, it is preferable that the cross-sectional areas of the plurality of grooves 30 in the width direction have variations. If the cross-sectional areas of the plurality of grooves 30 in the width direction are uneven, the iris phenomenon in the adhesive sheet can be suppressed.

Here, when the cross-sectional areas in the width direction of the plurality of grooves 30 vary, the standard deviation of the cross-sectional areas in the width direction of the plurality of grooves 30 is the average value of the cross-sectional areas in the width direction of the plurality of grooves 30. is preferably 5% or more, more preferably 7% or more, and preferably 20% or less. If the standard deviation of cross-sectional areas in the width direction of the plurality of grooves 30 is equal to or greater than the above lower limit, the iris phenomenon in the adhesive sheet can be further suppressed. On the other hand, when the standard deviation of the cross-sectional area of the grooves 30 in the width direction is equal to or less than the above upper limit, the cross-sectional area of the grooves does not become too small, so that good air release properties can be maintained.

[Groove depth]
The depth 36 of the groove 30A formed in the surface 11 of the resin layer 10 is required to be 0.5 μm or more, preferably 0.6 μm or more, and more preferably 0.7 μm or more. It is preferably not less than 0.8 μm, needs to be less than 10 μm, preferably less than 7 μm, more preferably less than 5 μm. When the depth 36 of the groove 30A is equal to or greater than the above lower limit, the air release property of the adhesive sheet can be enhanced. On the other hand, when the depth 36 of the grooves 30A is less than the upper limit, the transparency of the adhesive sheet can be favorably maintained. In the cross-sectional view of FIG. 2, the depth 36 of the groove 30A indicates the height of the trapezoid which is the cross-sectional shape of the groove in the width direction.

The depth 36 of one groove 30A may be the same or different from one longitudinal end of the groove 30A to the other longitudinal end. Assume that there is

The depths of the plurality of grooves 30 formed in the surface 11 of the resin layer 10 may be the same or different, but preferably different. That is, it is preferable that the depths of the plurality of grooves 30 are varied. If there is variation in the depth of the plurality of grooves 30, the iris phenomenon in the adhesive sheet can be suppressed.

Here, when the depths of the plurality of grooves 30 vary, the standard deviation of the depths of the plurality of grooves 30 is preferably 0.5 μm or more, more preferably 0.7 μm or more, and more preferably 2 μm. The following are preferable. If the standard deviation of the depths of the plurality of grooves 30 is equal to or greater than the above lower limit, the iris phenomenon in the adhesive sheet can be further suppressed. On the other hand, if the standard deviation of the depths of the plurality of grooves 30 is equal to or less than the above upper limit, there are no excessively shallow grooves and/or excessively deep grooves, so good air release and transparency can be maintained.

In this specification, when the standard deviation of the depths of the plurality of grooves 30 is greater than 0, that is, when the depths of the plurality of grooves 30 vary, the average value of the depths of the plurality of grooves 30 can be the same as the preferred range of the depth of the groove 30A described above.

[Groove opening width (width of upper bottom face)]
Moreover, it is preferable that the width (opening width) of the opening surface (upper bottom surface 33) of the groove 30A is larger than the depth 36 of the groove 30A. If the opening width of the grooves 30A is larger than the depth 36 of the grooves 30A, it is possible to further improve the air release property of the adhesive sheet.
The opening width of the groove 30A is preferably 1 μm or more, more preferably 2 μm or more, even more preferably 5 μm or more, preferably 30 μm or less, and more preferably 25 μm or less. It is preferably 15 μm or less, and more preferably 15 μm or less. If the opening width of the groove 30A is equal to or greater than the above lower limit, the air release property of the adhesive sheet can be further enhanced. On the other hand, if the opening width of the grooves 30A is equal to or less than the above upper limit, the transparency of the adhesive sheet can be further enhanced.

The opening width of one groove 30A may be the same or different from one end to the other in the longitudinal direction of the groove 30A. shall be
The opening widths of the plurality of grooves 30 formed on the surface 11 of the resin layer 10 may be the same or different, but are preferably different. That is, it is preferable that the opening widths of the plurality of grooves 30 have variations. If there is variation in the opening widths of the plurality of grooves 30, the iris phenomenon in the adhesive sheet can be suppressed.
Here, when the opening widths of the plurality of grooves 30 vary, the standard deviation of the opening widths of the plurality of grooves 30 is preferably 0.5 μm or more, more preferably 0.7 μm or more, and more preferably 1 μm. It is more preferably 3 μm or less, and preferably 3 μm or less. If the standard deviation of the opening widths of the plurality of grooves 30 is equal to or greater than the above lower limit, the iris phenomenon in the adhesive sheet can be further suppressed.
In addition, when the standard deviation of the opening width of the grooves 30 is more than 0, that is, when the opening widths of the plurality of grooves 30 vary, the preferable range of the average value of the opening widths of the plurality of grooves 30 is the grooves described above. It can be similar to the preferred range of aperture width of 30A.

[Inner wall surface S not parallel to surface direction of resin layer]
The groove 30A formed on the surface 11 of the resin layer 10 has an inner wall surface S35 that is not parallel to the surface direction of the resin layer 10. As shown in FIG. In addition, the inner wall surface S35 may be a slope inclined with respect to the surface direction of the resin layer 10 (that is, the inclination angle θ described later is an acute angle or an obtuse angle). It may be a vertical plane (that is, the inclination angle θ described later is a right angle).

The inclination angle θ of the inner wall surface S35 with respect to the surface direction of the resin layer 10 is not particularly limited, and may be an acute angle (more than 0° and less than 90°) or an obtuse angle (more than 90° and less than 180°). It may be a right angle (90°), but an acute angle (greater than 0° and less than 90°) is preferred. If the inclination angle θ of the inner wall surface S35 with respect to the plane direction of the resin layer 10 is an acute angle (greater than 0° and less than 90°), the mold can be easily released when the shape of the groove is transferred using a mold. productivity can be improved.
The inclination angle θ of the inner wall surface S35 with respect to the plane direction of the resin layer 10 is the plane parallel to the plane direction of the inner wall surface S35 and the resin layer 10 (in the illustrated example, the lower bottom surface 34 of the groove 30A). ), the angle formed on the outside of the groove 30</b>A and away from the support layer 20 .

Here, the inclination angle θ of one inner wall surface S35 of one groove 30A may be the same from one end to the other end in the longitudinal direction of the groove 30A, or may be different. may be used, but shall normally be the same.
Moreover, the inclination angles θ of the plurality of inner wall surfaces S35 of the plurality of grooves 30 formed on the surface 11 of the resin layer 10 may be the same or different. When the inclination angles θ of the plurality of inner wall surfaces S35 are different, the average value of the inclination angles θ of the plurality of inner wall surfaces S35 may be more than 0° and less than 90°, or more than 90° and less than 180°. However, it is preferably more than 0° and less than 90°. By setting the average value of the inclination angle θ of the plurality of inner wall surfaces S35 to more than 0° and less than 90°, it is easy to release when the shape is transferred using a mold, so the productivity of the adhesive sheet is improved. be able to.

[Area of projection]
When the surface of the resin layer is projected in the thickness direction of the resin layer with respect to a plane parallel to the resin layer, the ratio of the projected area of the inner wall surface S of the groove to the projected area of the entire surface of the resin layer is 10. % or less, preferably 7% or less, more preferably 5% or less, even more preferably 2.5% or less, preferably more than 0%, It is more preferably 0.1% or more, and even more preferably 0.5% or more. When the ratio of the projection area of the inner wall surface S to the projection area of the entire surface of the resin layer is 10% or less, the transparency of the pressure-sensitive adhesive sheet can be maintained satisfactorily. On the other hand, if the ratio of the projected area of the inner wall surface S to the projected area of the entire surface of the resin layer is more than 0%, when the inclination angle θ of the inner wall surface S is an acute angle, the air release property of the adhesive sheet is improved. can be further increased.
The ratio of the projected area of the inner wall surface S of the groove to the projected area of the entire surface of the resin layer when the surface of the resin layer is projected in the thickness direction of the resin layer with respect to a plane parallel to the resin layer. can be calculated based on the shape, dimensions and pitch of the grooves formed in the resin layer, the area of the surface of the resin layer, and the like.

For example, like the pressure-sensitive adhesive sheet 100 shown in FIGS. 1 and 2, a plurality of grooves 30 are formed in rows over the entire surface 11 of the resin layer 10, and the cross-sectional shape of the grooves 30 in the width direction is trapezoidal. , when the surface 11 of the resin layer 10 is projected in the thickness direction of the resin layer 10 with respect to a plane parallel to the resin layer 10, the inner wall surface S35 occupying the projected area of the entire surface 11 of the resin layer 10 The area ratio of the projection is given by the following formula (1):
(Proportion of the projected area of the inner wall surface S35 to the projected area of the entire surface 11 of the resin layer 10)
=[{(total area of upper bottom surface 33 of groove)-(total area of lower bottom surface 34 of groove)}/( projected area of entire surface 11 of resin layer 10)]×100 (1 )
can be calculated using In the above formula (1), the " projection area of the entire surface 11 of the resin layer 10" is the external dimensions (vertical and horizontal etc.).

<<Part where groove is not formed>>
In the pressure-sensitive adhesive sheet 100 shown in FIGS. 1 and 2, the surface roughness Ra of the portion of the surface 11 of the resin layer 10 where the grooves 30 are not formed is preferably less than 100 nm.
Further, the inclination angle of the portion of the surface 11 of the resin layer 10 where the grooves 30 are not formed is preferably less than 1° with respect to the surface direction of the resin layer.

<<Storage modulus>>
The storage modulus of the resin layer must be 7.0×10 ⁵ Pa or more, preferably 9.0×10 ⁵ Pa or more, and 1.0×10 ⁶ Pa or more. It is more preferably 1.0×10 ⁹ Pa or less, preferably 1.0×10 ⁸ Pa or less, and more preferably 1.0×10 ⁷ Pa or less. When the storage elastic modulus of the resin layer is within the predetermined range, the grooves formed in the resin layer are well retained, the air release property of the adhesive sheet is maintained well, and the reworkability of the adhesive sheet is enhanced. can be done.

<<Haze of resin layer>>
Moreover, it is preferable that the resin layer has excellent transparency. Specifically, the haze of the resin layer in which the grooves described above are not formed on the surface is preferably 10% or less, more preferably 5% or less, and even more preferably 3% or less. .
The haze of the resin layer with no grooves formed on the surface can be measured using "NDH4000" manufactured by Nippon Denshoku Co., Ltd. in accordance with JIS K7136.

<<Composition of resin layer>>
The resin constituting the resin layer is not particularly limited as long as the resin layer has the above-described predetermined storage elastic modulus and the desired effects of the present invention can be obtained, and known resins can be used. can be done. In addition to the resin, the resin layer contains other components such as ultraviolet absorbers, infrared absorbers, various inorganic particles, antioxidants, plasticizers, etc., within the range in which the desired effects of the present invention can be obtained. may be

Here, the resin constituting the resin layer includes UV-curable resins; block copolymers obtained by copolymerizing aromatic vinyl compounds and conjugated diene compounds, such as styrene-isoprene block copolymers, and hydrides thereof. ; polyolefin resins such as polyethylene and polypropylene; and the like can be used. One of these resins may be used alone, or two or more of them may be used in combination at any ratio.
From the viewpoint of improving the productivity of the pressure-sensitive adhesive sheet, it is preferable to use an ultraviolet curable resin as the resin. In other words, the resin layer is a cured product obtained by irradiating a composition containing an ultraviolet-curable resin (an ultraviolet-curable resin composition) with ultraviolet rays (which may be abbreviated as a “cured product of an ultraviolet-curable resin composition”). There is.) is preferable. When an ultraviolet curable resin is used, grooves can be formed on the surface of the resin layer at the same time that the resin layer is formed by irradiating the resin with ultraviolet rays to cure the resin, so productivity of the adhesive sheet can be improved. .

Here, the ultraviolet curable resin composition is not particularly limited as long as it contains an ultraviolet curable resin and a cured product can be obtained by irradiating ultraviolet rays, but an ultraviolet curable resin and a curing agent It is preferable to use an ultraviolet curable resin composition containing.

As the UV-curable resin, for example, one or two or more UV-curable polymers, oligomers, monomers, etc. containing reactive functional groups (reactive functional groups) such as acryloyl groups and methacryloyl groups in the molecule. can be mixed and used. When the UV-curable polymer, oligomer, monomer, or the like is irradiated with UV rays, the reactive functional groups react with each other and/or the reactive functional groups react with a curing agent, which will be described later, to obtain a cured product.

Here, although the UV-curable polymer is not particularly limited, it is preferable to use an UV-curable acrylic polymer. A UV-curable acrylic polymer is a UV-curable polymer having, as a main chain, an acrylic polymer obtained by polymerizing an acrylic monomer. Examples of acrylic monomers include ethylenically unsaturated carboxylic acid monomers such as (meth)acrylic acid; (meth)acrylic acid alkyl ester monomers such as methyl (meth)acrylate; and the like. In addition, in this specification, "(meth)acrylic acid" means acrylic acid and/or methacrylic acid.
Further, the ultraviolet-curable oligomer and monomer are not particularly limited, and known addition-polymerizable or cross-linkable monomers and oligomers having an ethylenically unsaturated group capable of radical polymerization can be used. .
Specific examples of these UV-curable polymers, oligomers, and monomers include (meth)acrylic acid, methyl (meth)acrylate, butyl (meth)acrylate, cyclohexane (meth)acrylate, dimethylaminomethyl (meth)acrylate, carbi tall (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, (meth)acrylamide, N-methylol (meth)acrylamide , styrene, acrylonitrile, N-vinylpyrrolidone, ethylene glycol (meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, pentaerythritol di(meth) acrylates, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, triethylene glycol divinyl ether hydroxybutyl vinyl ether, urethane (meth)acrylate, Polyester (meth)acrylate, epoxy (meth)acrylate and the like can be preferably used. These compounds can be used singly or in combination of two or more.
Note that the UV-curable polymer, oligomer, and monomer are components different from the curing agent described later.

Moreover, the curing agent is not particularly limited as long as it is a substance capable of curing the ultraviolet curing resin. As the curing agent, a polyfunctional acrylate compound having a total of 3 or more acryloyl groups and/or methacryloyl groups (hereinafter sometimes referred to as "(meth)acryloyl groups") per molecule is preferably used. If the UV-curable resin composition further contains a polyfunctional acrylate compound having a total of 3 or more (meth)acryloyl groups per molecule in addition to the UV-curable polymer, the intermolecular Formation of a crosslinked structure is accelerated, and an appropriate storage elastic modulus can be imparted to the resulting cured product as a resin.
Examples of polyfunctional acrylate compounds include triacrylate compounds having a total of three (meth)acryloyl groups in the molecule, such as trimethylolpropane triacrylate (TMPTA); a total of four (meth)acryloyl groups in the molecule. a tetraacrylate compound having; and the like can be used. These may be used individually by 1 type, and may be used in combination of 2 or more types by arbitrary ratios. Among them, triacrylate compounds are preferably used, and TMPTA is more preferably used, from the viewpoint of imparting an appropriate storage elastic modulus to the resulting cured product as a resin.

The content of the curing agent in the ultraviolet curable resin composition is preferably 0.5% by mass or more, more preferably 0.7% by mass or more, and is preferably 0.9% by mass or more. More preferably, it is 10% by mass or less, and more preferably 5% by mass or less. When the content of the curing agent in the ultraviolet-curable resin composition is at least the above lower limit, it is possible to impart an appropriate storage elastic modulus to the resulting cured product as a resin. On the other hand, if the content of the curing agent in the UV-curable resin composition is equal to or less than the above upper limit, excessive increase in the storage elastic modulus of the cured product as the obtained resin is suppressed, and the air release property of the pressure-sensitive adhesive sheet is improved. can be maintained well.

The ultraviolet curable resin and the ultraviolet curable resin composition may contain other components such as a photopolymerization initiator and a filler in addition to the ultraviolet curable resin and curing agent described above.

<<Method for Forming Resin Layer>>
The method for forming the resin layer described above is not particularly limited, and an appropriate method can be selected according to the properties of the resin used for the resin layer.
For example, a resin layer composed of a cured product of the ultraviolet-curable resin composition described above can be formed by the following method.
First, an ultraviolet curable resin composition is applied to the surface of a support to form a coating film of the ultraviolet curable resin composition. Next, the surface of the support on which the coating film is formed is placed in contact with the surface of the mold. Furthermore, by irradiating the coating film with ultraviolet rays to cure the ultraviolet-curable resin composition, a resin layer composed of a cured product of the ultraviolet-curable resin composition can be formed.
Here, the support on which the ultraviolet curable resin composition is applied is not particularly limited, and for example, the support layer described above can be used.
In addition, projections are formed on the surface of the mold used in the above method so that the above-described desired grooves are formed on the surface of the resin layer to be formed.
Furthermore, the conditions such as the wavelength of the ultraviolet rays and the irradiation time when the coating film of the ultraviolet-curable resin composition is irradiated with the ultraviolet rays can be appropriately set within a range in which the desired effects of the present invention can be obtained.

The thickness of the resin layer to be formed is not particularly limited as long as the desired effects of the present invention can be obtained, but it is preferably 5 μm or more, more preferably 10 μm or more, and 20 μm or more. More preferably, it is 500 µm or less, more preferably 300 µm or less, and even more preferably 200 µm or less. If the thickness of the resin layer is at least the above lower limit, even if the surface of the adherend has unevenness, the resin layer can adhere to the unevenness, so that the adhesive sheet can be well attached to the adherend. can be attached. On the other hand, if the thickness of the resin layer is equal to or less than the above upper limit, the transparency of the pressure-sensitive adhesive sheet can be maintained satisfactorily.

<Method for manufacturing adhesive sheet>
The method for producing the pressure-sensitive adhesive sheet of the present invention is not particularly limited. For example, in one example of the method for forming a resin layer described above, by using a support layer as the support, it is possible to produce the pressure-sensitive adhesive sheet of the present invention comprising a resin layer comprising a cured product of an ultraviolet-curable resin composition. can.

<Transparency of Adhesive Sheet>
The pressure-sensitive adhesive sheet of the present invention has excellent transparency. Specifically, the haze of the adhesive sheet of the present invention is preferably 10% or less, more preferably 7% or less, even more preferably 4% or less, and even more preferably 3% or less. preferable. If the haze value of the pressure-sensitive adhesive sheet is equal to or less than the predetermined value, the pressure-sensitive adhesive sheet is further excellent in transparency.
The haze of the pressure-sensitive adhesive sheet can be measured by the method described in the examples of this specification.

EXAMPLES The present invention will be specifically described below based on examples, but the present invention is not limited to these examples. "Parts" and "%" used herein are based on mass unless otherwise specified.
Various measurements, calculations and evaluations in Examples and Comparative Examples were carried out according to the following methods.

<Storage Elastic Modulus of Resin Layer>
For Examples 1 to 7, Example 9, and Comparative Examples 1 to 3 using an ultraviolet curable resin composition, a mold obtained by punching a silicone plate was used, and the ultraviolet curable resin prepared in each example and comparative example was used. The composition was cured by irradiating it with ultraviolet rays to obtain a sample for storage elastic modulus evaluation of 50 mm×5 mm×1 mm. The dose of ultraviolet rays (365 nm) was 4800 mJ/cm ² .
In Example 8 using a styrene-isoprene block copolymer, a solution of the styrene-isoprene block copolymer was applied onto a PET film ("HY-S10" manufactured by Higashiyama Film Co., Ltd.) after drying. It was applied to a film thickness of about 0.3 mm and dried on a hot plate. After that, the resin coating film was peeled off from the PET film, and the film was cut into a size of 50 mm×5 mm×0.3 mm to obtain a sample for evaluation of storage elastic modulus.
Then, using a dynamic viscoelasticity measuring device (manufactured by SII Nanotechnology Co., Ltd., model number: DMS6100), the distance between chucks is 20 mm, the temperature range is -60 to 80 ° C., the temperature increase rate is 3 ° C./min, and the frequency is 1 Hz. The storage modulus value at 25° C. was obtained by measuring under the conditions.

<Proportion of the projected area of the inner wall surface S to the projected area of the entire surface of the resin layer>
Regarding the pressure-sensitive adhesive sheets produced in Examples and Comparative Examples, when the surface of the resin layer is projected in the thickness direction of the resin layer with respect to a plane parallel to the resin layer, the grooves occupying the projected area of the entire surface of the resin layer The ratio of the projected area of the inner wall surface S (the inner wall surface that is not parallel to the surface direction of the resin layer) is expressed by the following formula (2):
(Proportion of the projected area of the inner wall surface S to the projected area of the entire surface of the resin layer)
= [{(total area of the upper bottom surface of the groove)-(total area of the lower bottom surface of the groove)}/( projected area of the entire surface of the resin layer)] x 100 (2)
Calculated by Note that the “projected area of the entire surface of the resin layer” in the above formula (2) is the external dimensions (vertical and horizontal length).

<Air release property>
The pressure-sensitive adhesive sheet produced in each example and comparative example was attached to a 0.7 mm thick glass plate ("Corning 1737" manufactured by Corning), and the interface between the resin layer of the pressure-sensitive adhesive sheet and the adherend (glass) The residual state of air bubbles was evaluated according to the following criteria. If no air bubbles remain at the interface between the resin layer of the adhesive sheet and the adherend (glass plate), it indicates that the adhesive sheet has excellent air release properties.
A: No air bubbles remain at the interface between the resin layer and the adherend (glass plate) B: Air bubbles remain at the interface between the resin layer and the adherend (glass plate)

<Groove holding state>
The pressure-sensitive adhesive sheet produced in each example and comparative example was attached to a glass plate having a thickness of 0.7 mm ("Corning 1737" manufactured by Corning), and the grooves formed on the surface of the resin layer were held. The ratio (groove retention rate) was measured by visual observation and evaluated according to the following criteria.
A: The groove retention rate is 50% or more.
B: The groove retention rate is less than 50%.

<Haze>
The pressure-sensitive adhesive sheet produced in each example and comparative example was attached to a glass plate having a thickness of 0.7 mm ("Corning 1737" manufactured by Corning) and measured in accordance with JIS K7136 with a haze meter ("NDH4000" manufactured by Nippon Denshoku Industries Co., Ltd.). ”) was used to measure the haze of the pressure-sensitive adhesive sheet. Incidentally, the smaller the haze value of the adhesive sheet, the more excellent the transparency of the adhesive sheet.

<Suppression of iris phenomenon>
The pressure-sensitive adhesive sheet produced in each example and comparative example was attached to a glass plate having a thickness of 0.7 mm ("Corning 1737" manufactured by Corning), and a white fluorescent tube ("FHF32EX-N-H" manufactured by Toshiba) was attached. , the white fluorescent tube was arranged so that the longitudinal direction of the white fluorescent tube and the longitudinal direction of the groove formed in the resin layer were aligned. Then, the pressure-sensitive adhesive sheet was irradiated with light from the white fluorescent tube, and the state of occurrence of the iris phenomenon in the pressure-sensitive adhesive sheet was evaluated. If the diffraction image of the fluorescent tube is not visible, it means that the adhesive sheet is able to suppress the iris phenomenon satisfactorily.
A: A diffraction image of the fluorescent tube cannot be seen, and the fluorescent tube can be seen as it is.
B: A plurality of faint diffraction images of the fluorescent tube can be seen.
C: A plurality of diffraction images of fluorescent tubes are clearly visible.

(Example 1)
3 parts of trimethylolpropane triacrylate, which is a triacrylate compound, was mixed with 100 parts of an ultraviolet curable resin to obtain an ultraviolet curable resin composition.
150 mm wide on the surface of a polyethylene terephthalate (PET) film ("A4300" manufactured by Toyobo Co., Ltd., length 300 mm x width 220 mm x thickness 125 µm) as a support layer, using an applicator, the above ultraviolet curable resin composition was applied to form a coating film having a thickness of 100 μm. The haze of the PET film was measured according to JIS K7136 using a haze meter (“NDH4000” manufactured by Nippon Denshoku Industries Co., Ltd.) and found to be 0.45%.
Next, the surface of the PET film on which the coating film was formed was placed in contact with the surface of the mold. Here, a plurality of projections are formed in rows at a pitch of 120 μm (pitch standard deviation δ: 0 μm) over the entire surface of the mold, and the width direction (lateral direction) of the projections is The cross-sectional shape was an isosceles trapezoid with an upper base of 18.85 μm/height of 1 μm/lower base of 20 μm. Next, the coating film was irradiated with ultraviolet rays from the support layer (PET film) side to cure the coating film of the UV-curable resin composition, thereby forming a resin layer (thickness: 100 μm) composed of the cured product. . The dose of ultraviolet rays (365 nm) was 4800 mJ/cm ² . Further, the die was released from the mold and punched out into a 100 mm square to obtain a 100 mm square pressure-sensitive adhesive sheet having a resin layer formed on one side in the thickness direction of the PET film (support layer).
In addition, a plurality of grooves are formed in a row over the entire surface of the resin layer of the obtained pressure-sensitive adhesive sheet, and the pitch of the grooves matches the pitch of the projections of the mold, and the cross section of the grooves in the width direction The shape coincided with the upside down cross-sectional shape of the mold in the width direction. Therefore, a plurality of grooves are formed in rows at a pitch of 120 μm (standard deviation δ of pitch: 0 μm) on the surface of the resin layer. It was an isosceles trapezoid of 85 μm. That is, the width (opening width) of the upper bottom surface of the groove was 20 μm, the depth of the groove was 1 μm, and the width of the lower bottom surface of the groove was 18.85 μm.
Using the obtained pressure-sensitive adhesive sheet, the storage modulus of the resin layer, the ratio of the projected area of the inner wall surface S to the projected area of the entire surface of the resin layer, the air release property of the pressure-sensitive adhesive sheet, the holding state of the grooves, and the haze. , and suppression of the iris phenomenon were measured, calculated and evaluated. Table 1 shows the results.

(Example 2)
In Example 1, the amount of TMPTA, which is a triacrylate compound, was changed from 3 parts to 1 part. / Except for changing the shape of the protrusion on the surface of the mold used so that it changes from an isosceles trapezoid with a lower base of 18.85 μm to an isosceles trapezoid with an upper base of 20 μm / height of 2 μm / lower base of 17.7 μm A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1. Then, in the same manner as in Example 1, various measurements, calculations and evaluations were performed. Table 1 shows the results.

(Example 3)
In Example 1, except that the pitch of the projections on the surface of the mold used was changed so that the pitch of the grooves formed in rows on the surface of the resin layer obtained changed from 120 μm to 240 μm. A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1. Then, in the same manner as in Example 1, various measurements, calculations and evaluations were performed. Table 1 shows the results.

(Example 4)
In Example 2, the pitch of the grooves formed in rows on the surface of the resulting resin layer was 120 μm (standard deviation: 0 μm), which was constant and had no variation, and the average value was 120 μm and the standard deviation was 1 A pressure-sensitive adhesive sheet was produced in the same manner as in Example 2, except that the pitch of the projections on the surface of the mold used was changed so that the pitch varied to 0.7 μm. Then, in the same manner as in Example 1, various measurements, calculations and evaluations were performed. Table 1 shows the results.

(Example 5)
In Example 1, the pitch of the grooves formed in rows on the surface of the obtained resin layer was changed from 120 μm to 220 μm, and the cross-sectional shape of the grooves in the width direction was 20 μm in upper base/1 μm in height/18 μm in lower base. Except for changing the pitch and shape of the protrusions on the surface of the mold used to change from an 85 μm isosceles trapezoid to an isosceles trapezoid with a top base of 20 μm/height of 3.5 μm/bottom of 7.8 μm. A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1. Then, in the same manner as in Example 1, various measurements, calculations and evaluations were performed. Table 1 shows the results.

(Example 6)
In Example 1, the pitch of the grooves formed in rows on the surface of the obtained resin layer was changed from 120 μm to 220 μm, and the cross-sectional shape of the grooves in the width direction was 20 μm in upper base/1 μm in height/18 μm in lower base. The same as in Example 1, except that the pitch and shape of the protrusions on the surface of the mold used were changed so as to change from an isosceles trapezoid of 85 μm to a triangle with an upper base of 11 μm/height of 3.3 μm/lower base of 0 μm. A pressure-sensitive adhesive sheet was produced in the same manner. Then, in the same manner as in Example 1, various measurements, calculations and evaluations were performed. Table 1 shows the results.

(Example 7)
In Example 6, the pitch of the projections on the surface of the mold used was changed so that the pitch of the grooves formed in rows on the surface of the resulting resin layer was changed from 220 μm to 520 μm. A pressure-sensitive adhesive sheet was produced in the same manner as in Example 6. Then, in the same manner as in Example 1, various measurements, calculations and evaluations were performed. Table 1 shows the results.

(Example 8)
35 parts of styrene-isoprene block copolymer was added to 65 parts of cyclohexane to obtain a styrene-isoprene block copolymer solution.
On the surface of a polyethylene terephthalate (PET) film ("A4300" manufactured by Toyobo Co., Ltd., length 300 mm x width 220 mm x thickness 125 µm) as a support layer, a styrene-isoprene block copolymer was applied with an applicator to a width of 150 mm. The solution was applied and dried on a hot plate at 100° C. to form a coating film having a thickness of 50 μm.
Next, the surface of the PET film on which the coating film is formed is brought into contact with the surface of the mold heated to 100 ° C. with a hot plate, and pressed with a rubber roller from the PET substrate side to the surface of the mold. The shape was transferred to the coating. Here, a plurality of projections are formed in rows at a pitch of 300 μm (pitch standard deviation δ: 0 μm) over the entire surface of the mold, and the width direction (lateral direction) of the projections is The cross-sectional shape was a triangle with an upper base of 0 μm/height of 4 μm/lower base of 8 μm. Further, the mold was released from the mold and punched out into a 100 mm square to obtain a 100 mm square pressure-sensitive adhesive sheet in which a resin layer having a thickness of 50 μm was formed on one side in the thickness direction of the PET film (support layer). In addition, a plurality of grooves are formed in a row over the entire surface of the resin layer of the obtained pressure-sensitive adhesive sheet, and the pitch of the grooves matches the pitch of the projections of the mold, and the cross section of the grooves in the width direction The shape coincided with the upside down cross-sectional shape of the mold in the width direction. Then, in the same manner as in Example 1, various measurements, calculations and evaluations were performed. Table 1 shows the results.

(Example 9)
In Example 2, the cross-sectional shape in the width direction of the plurality of grooves formed in rows on the surface of the resin layer obtained varied from an isosceles trapezoid with an upper base of 20 μm, a height of 2 μm, and a lower base of 17.7 μm. Centered on an isosceles trapezoid of 20 μm/height of 3.5 μm/lower base of 16 μm, the height of the cross-sectional shape (groove depth) is standardized at an average value of 3.5 μm while the inclination angle of the inner wall surface S is fixed. A pressure-sensitive adhesive sheet was produced in the same manner as in Example 2, except that the shape of the projections on the surface of the mold used was changed so that the deviation δ changed to a height with a variation of 0.5 μm. Then, in the same manner as in Example 1, various measurements, calculations and evaluations were performed. Table 1 shows the results.

(Comparative example 1)
In Example 1, the pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, except that the surface of the resin layer obtained was smooth and a smooth mold was used without protrusions on the surface so that grooves were not formed. manufactured. Then, in the same manner as in Example 1, various measurements, calculations and evaluations were performed. Table 1 shows the results.

(Comparative example 2)
In Example 1, the cross-sectional shape in the width direction of the grooves formed on the surface of the resin layer obtained was an isosceles trapezoid with an upper base of 20 μm/height of 1 μm/lower base of 18.85 μm to an isosceles trapezoid with an upper base of 20 μm/height of 12 μm/lower. A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that the shape of the protrusions on the surface of the mold used was changed so as to change to an isosceles trapezoid with a bottom of 6.15 μm. Then, in the same manner as in Example 1, various measurements, calculations and evaluations were performed. Table 1 shows the results.

(Comparative Example 3)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that the amount of TMPTA, which is a triacrylate compound, was changed from 3 parts to 0 parts. Then, in the same manner as in Example 1, various measurements, calculations and evaluations were performed. Table 1 shows the results.
In the resin layer of the pressure-sensitive adhesive sheet obtained in Comparative Example 3, since the retention rate of the grooves was less than 50%, when the entire pressure-sensitive adhesive sheet was observed, the variation in transparency was large depending on the presence or absence of the grooves. , an evaluation of haze could not be carried out properly.

(Comparative Example 4)
In Example 1, the cross-sectional shape of the plurality of grooves formed in rows on the surface of the resin layer obtained varied from an isosceles trapezoid with an upper base of 20 μm/height of 2 μm/lower base of 18.85 μm to an isosceles trapezoid with an upper base of 20 μm/height of 3. A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that the shape of the protrusions on the surface of the mold used was changed so as to change to an isosceles trapezoid of 0.5 μm/lower base of 7.8 μm. Then, in the same manner as in Example 1, various measurements, calculations and evaluations were performed. Table 1 shows the results.

From Table 1, a support layer and a resin layer having a predetermined storage elastic modulus formed on one side in the thickness direction of the support layer are provided, and grooves having a predetermined range of depth are formed on the surface of the resin layer. The groove has an inner wall surface S that is not parallel to the surface direction of the resin layer, and the ratio of the projected area of the inner wall surface S of the groove to the projected area of the entire surface of the resin layer is a predetermined value or less. It can be seen that the pressure-sensitive adhesive sheets of Examples 1 to 9 can satisfactorily achieve both air release properties and transparency.
On the other hand, it can be seen that the pressure-sensitive adhesive sheet of Comparative Example 1, in which grooves are not formed on the surface of the resin layer, has good transparency but is inferior in air release properties.
Further, the pressure-sensitive adhesive sheet of Comparative Example 2, in which the depth of the groove exceeds a predetermined range and the ratio of the projected area of the inner wall surface S of the groove to the projected area of the entire surface of the resin layer exceeds a predetermined value, It can be seen that although the air release property is good, the transparency is poor.
In addition, in the pressure-sensitive adhesive sheet of Comparative Example 3 using a resin layer having a storage elastic modulus below the predetermined range, the grooves formed in the resin layer were not maintained well, and the transparency could not be evaluated appropriately.
Furthermore, the pressure-sensitive adhesive sheet of Comparative Example 4, in which the depth of the groove is within a predetermined range, but the ratio of the projected area of the inner wall surface S of the groove to the projected area of the entire surface of the resin layer exceeds a predetermined value. It can be seen that, although the air release property is good, the transparency is poor.

According to the present invention, it is possible to provide a pressure-sensitive adhesive sheet that satisfactorily achieves both air release property and transparency.

REFERENCE SIGNS LIST 10 resin layer 11 surface 20 support layers 30, 30A, 30B grooves 31A, 31B edge 32 on one side in width direction pitch 33 upper bottom surface 34 lower bottom surface 35 inner wall surface S
36 depth 100 adhesive sheet

Claims (13)

A pressure-sensitive adhesive sheet comprising a support layer and a resin layer formed on at least one side in the thickness direction of the support layer,
A plurality of grooves having a depth of 0.5 μm or more and less than 10 μm are formed on the surface of the resin layer,
The groove has an inner wall surface S that is not parallel to the surface direction of the resin layer,
When the surface of the resin layer is projected in the thickness direction of the resin layer with respect to a plane parallel to the resin layer, the ratio of the projected area of the inner wall surface S to the projected area of the entire surface of the resin layer. is 10% or less,
The pressure-sensitive adhesive sheet, wherein the resin layer has a storage modulus of 7.0×10 ⁵ Pa or more and 1.0×10 ⁹ Pa or less. The pressure-sensitive adhesive sheet according to claim 1, wherein the depth of said grooves is less than 5 µm. The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the opening width of said groove is larger than the depth of said groove. The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein a plurality of said grooves are formed in a row. 5. The pressure-sensitive adhesive sheet according to claim 4, wherein the grooves formed in a plurality of rows have a pitch of less than 1000 [mu]m. The resin layer is made of a cured product of an ultraviolet curable resin composition containing an ultraviolet curable resin and a curing agent,
The pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the content of the curing agent in the ultraviolet-curable resin composition is 0.5% by mass or more. 6. The pressure-sensitive adhesive sheet according to claim 5, wherein the standard deviation of the pitch of the plurality of grooves formed in a row is 1 μm or more. The pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein the standard deviation of the opening widths of the plurality of grooves is 0.5 µm or more. The pressure-sensitive adhesive sheet according to any one of claims 1 to 8, wherein the standard deviation of the depth of the plurality of grooves is 0.5 µm or more. The pressure-sensitive adhesive sheet according to any one of claims 1 to 9, wherein the standard deviation of the cross-sectional areas in the width direction of the plurality of grooves is 3% or more of the average value of the cross-sectional areas in the width direction of the grooves. The pressure-sensitive adhesive sheet according to any one of claims 1 to 10, wherein the inclination angle of the inner wall surface S with respect to the surface direction of the resin layer is more than 0° and less than 90°. The pressure-sensitive adhesive sheet according to any one of claims 1 to 11, wherein the groove does not have an inner wall surface P parallel to the surface direction of the resin layer. The pressure-sensitive adhesive sheet according to any one of claims 1 to 12, wherein the groove has a triangular cross-sectional shape in the width direction.

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