Film, winding body, connecting structure, and method for manufacturing the connecting structure

Abstract

This film comprises: an elongated release film; a plurality of adhesive film strips disposed on the release film; and grooves that are formed on the surface on the side of the plurality of adhesive film strips of the release film, and that extend along the outer edge of each of the plurality of adhesive film strips, wherein the groove has a width of 15 μm or more.

Description

Technical Field

[0001] The present invention relates to a film, a wound body, a connection structure, and a method for manufacturing the connection structure.

Background Art

[0002] In recent years, devices such as smartphones, personal computers, earphones, smartwatches, and wearable devices have been becoming more highly functional, smaller, thinner, and more sophisticated in design. Along with this, the high functionality and integration of sensors, components, substrates, etc. mounted on these devices have also been progressing. Along with this, there are also increasing cases where a material with low heat resistance is used for some or all of sensors, components, substrates, etc., or a sensor, component, substrate, etc. with low heat resistance is mounted on a device, or another member is connected at a high temperature to a position close to a sensor, component, substrate, etc. with low heat resistance. Note that "connect" includes meanings such as adhere, mount, and install. As a result, there has been a demand for a technique for connecting another member only to one or a plurality of predetermined positions of sensors, components, substrates, etc. Moreover, the positions for connecting another member to sensors, components, substrates, etc. vary depending on the type of device, etc.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, it is conceivable to use a film provided with a plurality of adhesive film pieces on a release film as described in Patent Document 1 to attach the adhesive film pieces only to one or a plurality of predetermined positions of sensors, components, substrates, etc. Such a film is generally used as a wound body wound around a core.

[0005] However, since the adhesive forming the adhesive film piece is not completely cured, it tends to deform over time, spreading along the surface of the release film. Also, when winding the film onto the core, a predetermined tension is applied to the release film, so in the wound body, the film is under pressure toward the core (center). This pressure is generated by winding the film and is therefore also called winding pressure. Winding pressure increases toward the center. As a result, the adhesive film piece, sandwiched between the inner layer (core side) and outer layer (opposite side of the core) by the release film, is pressed from both sides by the release film and tends to deform, spreading out along the surface of the release film.

[0006] When adhesive film fragments deform and are pushed outwards along the surface of the release film, they tend to protrude from the adhesive surface, resulting in a lower yield. In particular, with anisotropic conductive films, the adhesive forming the adhesive film fragments contains a liquid resin component, which makes the deformation of the adhesive film fragments along the surface of the release film more pronounced, further worsening the yield.

[0007] Therefore, one aspect of the present invention aims to provide a film, a wound body, a connecting structure, and a method for manufacturing the connecting structure that can suppress the spreading of adhesive film pieces. [Means for solving the problem]

[0008] The inventors of this invention conducted thorough research on the above problem and found that by forming grooves on the surface of the release film piece and setting the width of the grooves to a predetermined value or greater, the spreading of the adhesive film piece can be suppressed. This invention is based on the above finding.

[0009] In other words, a film according to one aspect of the present invention comprises a long release film, a plurality of adhesive film pieces provided on the release film, and grooves formed on the surface of the plurality of adhesive film pieces of the release film and extending along the outer edges of each of the plurality of adhesive film pieces, wherein the width of the grooves is 15 μm or more.

[0010] In this film, multiple adhesive film pieces are provided on the release film, and each of the multiple adhesive film pieces tends to spread along the surface of the release film. However, the release film has grooves formed on the surface of the multiple adhesive film pieces that extend along the outer edge of each of the multiple adhesive film pieces, and the width of the grooves is 15 μm or more. Therefore, the spreading of each of the multiple adhesive film pieces along the surface of the release film is prevented by the grooves, thereby suppressing each of the multiple adhesive film pieces from spreading beyond the grooves.

[0011] The grooves may be located outside the outer edge of each of the multiple adhesive film pieces. In this film, having the grooves located outside the outer edge of each of the multiple adhesive film pieces can further suppress the spreading of each of the multiple adhesive film pieces.

[0012] The groove depth may be 10% or more of the thickness of the release film. In this film, having a groove depth of 10% or more of the thickness of the release film makes it easy to make the groove width 15 μm or more, and also lengthens the path for each of the multiple adhesive film pieces to cross the groove. This further suppresses the spreading of each of the multiple adhesive film pieces beyond the groove.

[0013] The groove depth may be 85% or less of the thickness of the release film. In this film, having a groove depth of 85% or less of the thickness of the release film can suppress the tearing of the release film.

[0014] The groove depth may be 20% or more of the thickness of the adhesive film piece surrounded by the groove among the multiple adhesive film pieces. In this film, having a groove depth of 20% or more of the thickness of the adhesive film piece surrounded by the groove allows for a longer path for each of the multiple adhesive film pieces to cross the groove. This further suppresses the spreading of each of the multiple adhesive film pieces beyond the groove.

[0015] The groove depth may be 100% or less of the thickness of the adhesive film piece surrounded by the groove among the multiple adhesive film pieces. In this film, grooves can be easily formed by having a groove depth of 100% or less of the thickness of the adhesive film piece surrounded by the groove.

[0016] The adhesive forming each of the multiple adhesive film pieces may have a multilayer structure. In this film, the multilayer structure of the adhesive forming each of the multiple adhesive film pieces makes it easier for each of the multiple adhesive film pieces to spread. However, as mentioned above, since there are grooves with a width of 15 μm or more, it is possible to suppress each of the multiple adhesive film pieces from spreading beyond the grooves.

[0017] The degree of curing of the adhesive forming each of the multiple adhesive film pieces, as measured by differential scanning calorimetry, may be 80% or higher under the condition of 150°C for 10 seconds. In this film, if the degree of curing of the adhesive forming each of the multiple adhesive film pieces, as measured by differential scanning calorimetry, is 80% or higher under the condition of 150°C for 10 seconds, the thermal effects on areas other than the connection points can be reduced.

[0018] Multiple adhesive film pieces may be spaced apart from each other. In this film, the spacing between adhesive film pieces allows them to be attached to the bonding surface without affecting adjacent adhesive film pieces. This makes it easy to attach adhesive film pieces to the bonding surface.

[0019] The plurality of adhesive film pieces may be spaced apart from the edge of the release film in the width direction of the release film. In this film, since the plurality of adhesive film pieces are spaced apart from the edge of the release film in the width direction of the release film, when the end portion of the release film interferes with other members, etc., it is possible to suppress the peeling of the adhesive film pieces from the release film.

[0020] The plurality of adhesive film pieces may be arranged in a row in the longitudinal direction of the release film. In this film, since the plurality of adhesive film pieces are arranged in a row in the longitudinal direction of the release film, the adhesive film pieces can be easily attached.

[0021] At least one of the plurality of adhesive film pieces may have a hole. In this film, since at least one of the plurality of adhesive film pieces has a hole, for example, it is possible to appropriately attach the adhesive film piece to a portion having a location where it is not desired to attach the adhesive film piece at the central portion.

[0022] The plurality of adhesive film pieces may have the same shape. In this film, since the plurality of adhesive film pieces have the same shape, the adhesive film pieces can be efficiently attached continuously or simultaneously to a plurality of adhesive surfaces having the same shape.

[0023] The adhesive film piece may have conductivity. In this film, since the adhesive film piece has conductivity, it is possible to conduct two members connected via the adhesive film piece.

[0024] The adhesive film piece may contain conductive particles. In this film, since the adhesive film piece contains conductive particles, it is possible to easily impart conductivity to the adhesive film piece.

[0025] The wound body according to one aspect of the present invention includes any one of the above films and a core around which the film is wound.

[0026] In this wound body, since any one of the above films is wound around the core, a winding pressure that is pressurized toward the core (center) is generated in the film. Therefore, the adhesive film pieces sandwiched between the inner layer side (core side) and the outer layer side (opposite side to the core) by the release film are pressed from the inner layer side and the outer layer side by the release film and tend to deform so as to be spread along the surface of the release film. However, the film has grooves formed on the surface on the side of the plurality of adhesive film pieces of the release film and extending along the outer edges of the respective plurality of adhesive film pieces, and the width of the grooves is 15 μm or more. Therefore, the spread of each of the plurality of adhesive film pieces along the surface of the release film is blocked by the grooves, so that it is possible to suppress each of the plurality of adhesive film pieces from spreading beyond the grooves.

[0027] A connection structure according to one aspect of the present invention includes a first member having a first adhesive surface, a second member having a second adhesive surface, and any one of the above adhesive film pieces connecting the first adhesive surface and the second adhesive surface.

[0028] In this connection structure, since the first member and the second member are connected by any one of the above adhesive film pieces, it is possible to obtain a connection structure in which the protrusion of the adhesive film piece from the first member and the second member is suppressed.

[0029] A method for manufacturing a connection structure according to one aspect of the present invention includes a preparation step of preparing any one of the above films, and a connection step of connecting a first adhesive surface of a first member and a second adhesive surface of a second member through an adhesive film piece of the film.

[0030] In this manufacturing method of the connection structure, since the first adhesive surface of the first member and the second adhesive surface of the second member are connected through the adhesive film piece of any one of the above films, it is possible to manufacture a connection structure in which the protrusion of the adhesive film piece from the first member and the second member is suppressed.

Advantages of the Invention

[0031] According to the present invention, the spreading of adhesive film pieces can be suppressed. [Brief explanation of the drawing]

[0032] [Figure 1] Figure 1 is a plan view showing a partial example of the film according to this embodiment. [Figure 2] Figure 2 is a perspective view showing the wound body according to this embodiment. [Figure 3] Figure 3 is a cross-sectional view showing an example of a cross-section along the line III-III shown in Figure 1. [Figure 4] Figure 4 is a cross-sectional view showing another example of the cross-section along the line III-III shown in Figure 1. [Figure 5] Figure 5 is a cross-sectional view showing another example of the cross-section along line III-III shown in Figure 1. [Figure 6] Figure 6 is a plan view showing another example of a part of the film. [Figure 7] Figures 7(a), 7(b), and 7(c) are plan views showing other examples of parts of the film. [Figure 8] Figure 8 is a plan view showing another example of a part of the film. [Figure 9] Figure 9 is a plan view showing another example of a part of the film. [Figure 10] Figure 10 is a flowchart showing the method for manufacturing a film according to an embodiment. [Figure 11] Figures 11(a), 11(b), 11(c), and 11(d) are cross-sectional views illustrating the manufacturing method of the film shown in Figure 1. [Figure 12] Figures 12(a), 12(b), 12(c), and 12(d) are perspective views illustrating the manufacturing method of the film shown in Figure 1. [Figure 13] Figure 13 is a cross-sectional view showing a connection structure according to this embodiment. [Figure 14] Figure 14 is a flowchart showing the method for manufacturing the connection structure according to this embodiment. [Figure 15]Figure 15 is a flowchart showing the connection process shown in Figure 14. [Figure 16] Figure 16 is a schematic process diagram illustrating the connection process shown in Figure 14. [Figure 17] Figure 17 is a schematic diagram of the observation surface of Example 1. [Figure 18] Figure 18 is a schematic diagram of the observation surface of Example 2. [Figure 19] Figure 19 is a schematic diagram of the observation surface of Example 3. [Figure 20] Figure 20 is a schematic diagram of the observation surface of Example 4. [Figure 21] Figure 21 is a schematic diagram of the observation surface of Comparative Example 1. [Figure 22] Figure 22 is a table showing the observation results for Examples 1-4 and Comparative Example 1. [Modes for carrying out the invention]

[0033] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions are omitted. In addition, in the drawings, dimensional proportions and other elements have been appropriately modified to make the explanations easier to understand.

[0034] [film] As shown in Figure 1, the film 1 comprises a long (tape-shaped) release film 2, a plurality of adhesive film pieces 3 provided on the release film 2, and grooves 4 (see Figures 3 to 5) formed on the surface 2a of the release film 2 on the side with the plurality of adhesive film pieces 3, extending along the outer edges 3a of each of the plurality of adhesive film pieces 3. The film 1 is stored and transported as a wound body 15 wound around a core 14, as shown in Figure 2.

[0035] (Release film) The release film 2 is attached to a plurality of adhesive film pieces 3 to support the plurality of adhesive film pieces 3. The material of the release film 2 can be, for example, polyethylene terephthalate (PET), polyethylene, polypropylene, etc. The release film 2 may contain any filler. In addition, the surface of the release film 2 may be treated with a release treatment, plasma treatment, antistatic treatment, etc.

[0036] Incidentally, when attaching an adhesive film piece 3 to the bonding surface (not shown) of an object to be bonded (not shown) with high precision, it is preferable to determine the position of the adhesive film piece 3 on the film 1. For example, the release film 2 may be provided with alignment marks for determining the position of the adhesive film piece 3 on the film 1, and the position of the adhesive film piece 3 may be determined based on these alignment marks. Alternatively, the position of the adhesive film piece 3 on the film 1 may be determined by detecting the specific arrangement of the adhesive film piece 3 on the film 1. Therefore, it is conceivable to detect the position of the adhesive film piece 3 on the film 1 using an imaging device 33 (see Figure 16). However, considering that the adhesive film piece 3 will be attached to the bonding surface afterward, it is preferable to position the imaging device 33 on the opposite side of the adhesive film piece 3 from the release film 2.

[0037] Therefore, the release film 2 may be light-transmitting so that the position of the adhesive film piece 3 can be detected from the release film 2 side by the imaging device 33.

[0038] In this case, the transmittance of the release film 2 can be 15% or more and 100% or less, preferably 15% or more and 99% or less, and more preferably 16% or more and 98% or less.

[0039] The transmittance of release film 2 can be measured as follows: A 50mm x 50mm square piece of release film is placed in a haze meter (for example, NDH-5000 manufactured by Nippon Denshoku Industries Co., Ltd.), and the total light transmittance is measured. This measurement result is then taken as the transmittance of release film 2.

[0040] The haze value of the release film 2 can be 3% or more and 100% or less, preferably 3% or more and 99% or less, and more preferably 4% or more and 99% or less.

[0041] The haze value of release film 2 can be measured as follows: Place a 50mm x 50mm square piece of release film into a haze meter (for example, NDH-5000 manufactured by Nippon Denshoku Industries Co., Ltd.) and measure the haze value. This measurement result is then taken as the haze value of release film 2.

[0042] (Adhesive film piece) Each of the multiple adhesive film pieces 3 (hereinafter also simply referred to as "adhesive film piece 3") connects the first member and the second member to be bonded. Therefore, from the viewpoint of facilitating good bonding, the adhesive film pieces 3 may have the same thickness. Also, from the viewpoint of facilitating good bonding, the adhesive film pieces 3 may have a flat surface. That is, the surface of the adhesive film piece 3 on the side facing the release film 2 and the surface of the adhesive film piece 3 opposite to the release film 2 may be flat. "Same thickness" means not only perfectly identical thickness but also including a thickness error of approximately ±10%. Also, "flat surface" means not only a perfectly flat surface but also including a flatness error of approximately ±10%. As shown in Figures 3 to 5, the adhesive film piece 3 has a film-like adhesive 6.

[0043] The adhesive 6 that forms the adhesive film piece 3 can, for example, have a multilayer structure. Examples of multilayer structures include a structure in which adhesive films with different components are layered and coated, and a structure in which separate adhesive films are bonded together.

[0044] As the adhesive 6 for forming the adhesive film piece 3, for example, a thermoplastic resin, a thermosetting resin, a mixture of a thermoplastic resin and a thermosetting resin, or a photocurable resin can be used. As thermoplastic resins, for example, styrene resins and polyester resins can be used. As thermosetting resins, for example, epoxy resins, acrylic resins, and silicone resins can be used. When using thermoplastic resins or thermosetting resins, heating and pressurizing are usually required. In the case of thermoplastic resins, this is to allow the resin to flow and obtain adhesion to the adherend, and in the case of thermosetting resins, it is necessary to further cure the resin. Furthermore, since photocurable resins do not require heating for curing, they are useful when bonding at low temperatures is required.

[0045] As the adhesive 6 forming the adhesive film piece 3, from the viewpoint of minimizing the thermal effects on areas other than the connection point, for example, a resin may be used that has a curing degree of 80% or more at 150°C for 10 seconds, 160°C for 10 seconds, 170°C for 10 seconds, 180°C for 10 seconds, 200°C for 10 seconds, 210°C for 10 seconds, or 230°C for 10 seconds, as measured by differential scanning calorimetry (DSC). These resin properties can also be selected to be optimal according to the reliability level required for the final device. The curing degree measured by differential scanning calorimetry can be calculated using a differential scanning calorimeter (e.g., TA Instruments DSC Q-2500) from the difference between the heat generated by the uncured resin and the residual heat generated by the cured resin.

[0046] The adhesive film piece 3 may be conductive or non-conductive. For example, the adhesive film piece 3 may be formed from a conductive adhesive film or a non-conductive adhesive film, or it may be formed from a hybrid adhesive film having conductive adhesive regions and non-conductive adhesive regions in the thickness direction or planar direction of the adhesive film. Furthermore, the adhesive film piece 3 may consist of two layers, a first adhesive layer and a second adhesive layer, or it may consist of three or more layers comprising a first adhesive layer, a second adhesive layer and a third adhesive layer. The first adhesive layer, the second adhesive layer and the third adhesive layer may be conductive or non-conductive.

[0047] The conductive adhesive film forming the adhesive film piece 3 may, for example, have isotropic conductivity or anisotropic conductivity. For example, as shown in Figure 4, conductivity can be easily achieved by including conductive particles 7. The conductive particles 7 are, for example, contained in the adhesive 6.

[0048] Examples of conductive particles 7 include metal particles such as Au, Ag, Ni, Cu, Pd, and solder, as well as carbon particles. The conductive particles 7 may also be formed by coating the surface of transition metals such as Ni and Cu with noble metals such as Au, Ag, and Pd. Furthermore, the conductive particles 7 may have a conductive layer formed on the surface of non-conductive particles, such as glass, ceramic, or plastic, by coating the surface of the non-conductive particles with a conductive material. The conductive particles 7 may also be formed by using noble metals for the outermost layer, or by using molten metal particles.

[0049] The conductive particles 7 may be, for example, conductive particles having an isotropic shape such as a substantially spherical shape. Conductive particles having an isotropic shape refer to, for example, conductive particles having a substantially point-symmetric shape. From the viewpoint of achieving good connection characteristics even when an oxide film is formed on the electrode surface of the connecting members, the conductive particles 7 may be conductive particles having an anisotropic shape such as a dendritic shape (also called a tree-like shape) or a flake shape (also called a flat plate shape or scale-like shape). Conductive particles having an anisotropic shape refer to, for example, conductive particles having shape anisotropy and not having a substantially point-symmetric shape (isotropic shape). The anisotropic shape of the conductive particles 7 allows them to penetrate the oxide film on the electrode surface and achieve good connection characteristics. The conductive particles 7 may be used individually or in combination of two or more types.

[0050] The hybrid adhesive film forming the adhesive film piece 3 may, for example, be one in which a conductive adhesive region 8 and a non-conductive adhesive region 9 are arranged adjacently on the release film 2, as shown in Figure 5. The conductive adhesive region 8 may contain conductive particles 7, similar to a conductive adhesive film.

[0051] The multiple adhesive film pieces 3 may be spaced apart in the longitudinal direction X of the release film 2, or they may be connected in the longitudinal direction X of the release film 2. As shown in Figure 1, in this embodiment, the multiple adhesive film pieces 3 are spaced apart in the longitudinal direction X of the release film 2. However, as shown in film 1 in Figure 6, the multiple adhesive film pieces 3 may be connected in the longitudinal direction X of the release film 2.

[0052] When adjacent adhesive film pieces 3 are spaced apart in the longitudinal direction of the release film 2, the distance between adjacent adhesive film pieces 3 in the longitudinal direction X can be 0.1 mm or more and 20 mm or less, 0.1 mm or more and 15 mm or less, 0.1 mm or more and 10 mm or less, 0.1 mm or more and 8 mm or less, or 0.2 mm or more and 5 mm or less. When the distance between adjacent adhesive film pieces 3 in the longitudinal direction X is within the above range, the transport distance of the film 1 can be shortened when attaching adjacent adhesive film pieces 3 to another component, and the film 1 can be used effectively to reduce costs.

[0053] The shape of the adhesive film piece 3 is not particularly limited and can be various shapes. For example, the shape of the adhesive film piece 3 can be a circle, an ellipse or other circular shape, a polygon such as a triangle or a square, a star shape, a mark or other complex shape. Examples of squares include squares, rectangles, and trapezoids.

[0054] As shown in Figures 7(a), 7(b), and 7(c), the adhesive film piece 3 may have holes 3b. The holes 3b are formed by cutting out (punching out) a part of the adhesive film piece 3. The shape, size, position, number, etc. of the holes 3b are not particularly limited. For example, the holes 3b may be similar in shape to the adhesive film piece 3, or they may not be similar in shape to the adhesive film piece 3. Examples of hole shapes include circles such as perfect circles and ellipses, polygons such as triangles and squares, star shapes, and complex shapes such as various marks. Examples of squares include squares, rectangles, and trapezoids. The position of the holes 3b may be in the center of the adhesive film piece 3, or at the edge of the adhesive film piece 3. The number of holes 3b formed in a single adhesive film piece 3 may be one, or two or more. If multiple holes 3b are formed in a single adhesive film piece 3, the shape, size, etc. of each hole 3b may be the same, or they may be different. The adhesive film piece 3 shown in Figure 7(a) has a rectangular shape, and a rectangular hole 3b similar to the shape of the adhesive film piece 3 is formed in its center. The adhesive film piece 3 shown in Figure 7(b) has a circular shape, and a circular hole 3b similar to the shape of the adhesive film piece 3 is formed in its center. The adhesive film piece 3 shown in Figure 7(c) has a rectangular shape, and a circular rectangular hole 3b is formed in its center.

[0055] The multiple adhesive film pieces 3 may be arranged in a single row along the longitudinal direction X of the release film 2, or they may be arranged in multiple rows along the longitudinal direction X of the release film 2. When the multiple adhesive film pieces 3 are arranged in a single row along the longitudinal direction X of the release film 2, only these multiple adhesive film pieces 3 arranged in a single row are provided on the release film 2. When the multiple adhesive film pieces 3 are arranged in a single row along the longitudinal direction X of the release film 2, the multiple adhesive film pieces 3 may be arranged in the center of the release film 2 in the width direction Y, as shown in film 1 in Figure 1, or they may be arranged at a position offset from the center of the release film 2 in the width direction Y, as shown in film 1 in Figure 8.

[0056] Multiple adhesive film pieces 3 may have the same shape, or they may have different shapes, as shown in film 1 in Figure 9. If multiple adhesive film pieces 3 have different shapes, all adhesive film pieces 3 may have different shapes from each other, or there may be a mixture of adhesive film pieces 3 with different shapes and adhesive film pieces 3 with the same shape from each other.

[0057] Multiple adhesive film pieces 3 may be spaced apart from the edge of the release film 2 in the width direction Y of the release film 2. In this case, the distance between the edge of the release film 2 and the adhesive film piece 3 closest to the edge in the width direction Y of the release film 2 can be 0.1 mm or more and 20 mm or less, 0.1 mm or more and 15 mm or less, 0.1 mm or more and 10 mm or less, 0.1 mm or more and 8 mm or less, or 0.2 mm or more and 5 mm or less.

[0058] (groove) As shown in Figures 1 and 3-5, the groove 4 is formed on the surface 2a of the release film 2 on the side with the multiple adhesive film pieces 3, and does not extend to the back surface 2b of the release film 2 on the opposite side of the multiple adhesive film pieces 3. In other words, the groove 4 is recessed from the surface 2a of the release film 2 in the thickness direction Z of the film 1, which is perpendicular to the longitudinal direction X and the width direction Y, so as not to reach the back surface 2b of the release film 2 on the opposite side of the multiple adhesive film pieces 3. The groove 4 is also called a half-cut line.

[0059] The groove 4 may extend in a solid line or a dashed line, as long as it extends along the outer edge 3a of each of the multiple adhesive film pieces 3. A groove 4 extending in a solid line means that it extends continuously without interruption. A groove 4 extending in a dashed line means that it extends discontinuously, with partial interruptions at one or more locations. The partial interruptions in the groove 4 are also called breaks in the groove 4. When the groove 4 extends in a dashed line, the breaks in the groove 4 may be formed at predetermined intervals or at arbitrary positions.

[0060] The grooves 4 are formed on the surface 2a of the release film 2 to prevent each of the multiple adhesive film pieces 3 from spreading along the surface 2a of the release film 2. The width (line width) of the grooves 4 is 15 μm or more. The width of the grooves 4 is the width on the surface 2a of the release film 2 and is the width in the direction perpendicular to the direction of extension of the grooves 4. Since the grooves 4 extend along the outer edges 3a of each of the multiple adhesive film pieces 3, the direction of extension of the grooves 4 differs depending on the position where the grooves 4 are formed. Therefore, the width of the grooves 4 is the width in the direction perpendicular to the direction of extension of the grooves 4 at the point where the grooves 4 are formed. From the viewpoint of preventing each of the multiple adhesive film pieces 3 from spreading along the surface 2a of the release film 2, the width of the grooves 4 is preferably 20 μm or more. On the other hand, from the viewpoint of easily forming the grooves 4, the width of the grooves 4 is preferably 50 μm or less, more preferably 45 μm or less, and even more preferably 40 μm or less. From these perspectives, the width of the groove 4 is preferably 15 μm or more and 50 μm or less, more preferably 15 μm or more and 45 μm or less, and even more preferably 20 μm or more and 40 μm or less.

[0061] The groove 4 may be located in a position that overlaps with the outer edge 3a of each of the multiple adhesive film pieces 3, or it may be located outside the outer edge 3a of each of the multiple adhesive film pieces 3. In these cases, the groove 4 will have substantially the same shape as each of the multiple adhesive film pieces 3 in a plan view of the film 1, that is, the same shape as or slightly larger than each of the multiple adhesive film pieces 3. A plan view of the film 1 refers to the view from the plane direction of the release film 2 (a direction perpendicular to the surface 2a of the release film 2), as shown in Figure 1. Figures 3 to 5 show the case where the groove 4 is located outside the outer edge 3a of each of the multiple adhesive film pieces 3.

[0062] The depth of the groove 4 is not particularly limited and can be set appropriately within a range that does not penetrate the release film 2. The depth of the groove 4 is the depth in the thickness direction Z of the film 1. For example, from the viewpoint of easily forming the groove 4 and lengthening the path for each of the multiple adhesive film pieces 3 to cross the groove 4, the depth of the groove 4 is preferably 10% or more of the thickness of the release film 2, more preferably 20% or more of the thickness of the release film 2, and even more preferably 30% or more of the thickness of the release film 2. On the other hand, from the viewpoint of suppressing the tearing of the release film 2, the depth of the groove 4 is preferably 85% or less of the thickness of the release film 2, more preferably 80% or less of the thickness of the release film 2, and even more preferably 75% or less of the thickness of the release film 2. From these viewpoints, the depth of the groove 4 is preferably 10% or more and 85% or less of the thickness of the release film 2, more preferably 20% or more and 80% or less of the thickness of the release film 2, and even more preferably 30% or more and 75% or less of the thickness of the release film 2.

[0063] From the viewpoint of making the path for each of the multiple adhesive film pieces 3 to cross the groove 4 longer, the depth of the groove 4 is preferably 20% or more of the thickness of the adhesive film piece 3 surrounded by the groove 4, more preferably 30% or more of the thickness of the adhesive film piece 3 surrounded by the groove 4, and even more preferably 40% or more of the thickness of the adhesive film piece 3 surrounded by the groove 4. On the other hand, from the viewpoint of easily forming the groove 4, the depth of the groove 4 is preferably 100% or less of the thickness of the adhesive film piece 3 surrounded by the groove 4, more preferably 90% or less of the thickness of the adhesive film piece 3 surrounded by the groove 4, and even more preferably 80% or less of the thickness of the adhesive film piece 3 surrounded by the groove 4. From these viewpoints, the depth of the groove 4 is preferably 20% to 100% of the thickness of the adhesive film piece 3 surrounded by the groove 4, more preferably 30% to 90%, and even more preferably 40% to 80%. The thickness of the adhesive film piece 3 is the thickness in the thickness direction Z of the film 1, similar to the depth of the groove 4. Furthermore, since the groove 4 extends along the outer edge 3a of each of the multiple adhesive film pieces 3, each of the multiple adhesive film pieces 3 is surrounded by the groove 4. For this reason, if one adhesive film piece 3 is designated as the target adhesive film piece, and the groove 4 extending along the outer edge 3a of the target adhesive film piece is designated as the target groove, then the adhesive film piece 3 surrounded by the groove 4 becomes the target adhesive film piece surrounded by the target groove.

[0064] [Film manufacturing method] As shown in Figure 10, the method for manufacturing the film includes, for example, an adhesive film layer formation step (S11), an adhesive film layer cutting step (S12) performed after the adhesive film layer formation step (S11), and an excess peeling step (S13) performed after the adhesive film layer cutting step (S12).

[0065] In the adhesive film layer formation step (S11), first, a release film 2 is prepared as shown in Figures 11(a) and 12(a). Then, as shown in Figures 11(b) and 12(b), an adhesive film layer 3A is formed over the entire surface of the release film 2. The adhesive film layer 3A is a layer that will become a plurality of adhesive film pieces 3. The adhesive film layer 3A is formed, for example, by an adhesive 6 and conductive particles 7 contained in the adhesive 6. The adhesive 6 and conductive particles 7 that form the adhesive film layer 3A are the same as the adhesive 6 and conductive particles 7 that form the adhesive film pieces 3 described above.

[0066] In the adhesive film layer cutting step (S12), as shown in Figures 11(c) and 12(c), the adhesive film layer 3A formed on the release film 2 is cut along the outer edge line 3B that forms the outer edge 3a of the plurality of adhesive film pieces 3 provided on the film 1, and the release film 2 is half-cut. The cutting of the adhesive film layer 3A and the half-cutting of the release film 2 are performed, for example, by pressing the adhesive film layer 3A against a roll cutter with a cutting blade formed on its outer surface. As the cutting blade, for example, a Pinnacle® blade or a Thomson blade can be used. Half-cutting the release film 2 means cutting the surface 2a of the release film 2 on the side of the adhesive film layer 3A such that the back surface 2b on the opposite side of the adhesive film layer 3A is not cut. As a result, cutting lines are formed on the adhesive film layer 3A along the outer edge 3a of each of the plurality of adhesive film pieces 3 provided on the film 1, and half-cut lines are formed on the release film 2 along the outer edge 3a of each of the plurality of adhesive film pieces 3 provided on the film 1. At this time, the release film 2 is half-cut so that the width of the half-cut line of the release film 2 is 15 μm or more. The width of the half-cut line of the release film 2 can be made 15 μm or more by appropriately setting the thickness of the cutting blade, the shape of the blade, the depth of the cut of the cutting blade into the release film 2, etc. As a result, the adhesive film layer 3A is separated into an inner portion 3A1 located inside the outer edge line 3B and a plurality of margin portions 3A2 located outside the outer edge line 3B. The inner portion 3A1 is the portion that will become the plurality of adhesive film pieces 3 provided on the film 1. The margin portions 3A2 are the portions other than the plurality of adhesive film pieces 3 provided on the film 1.

[0067] In the excess peeling step (S13), as shown in Figures 11(d) and 12(d), the excess portion 3A2 of the adhesive film layer 3A is peeled off from the release film 2 along the cut outer edge line 3B. The excess portion 3A2 is peeled off, for example, by attaching adhesive tape to the excess portion 3A2, pulling the adhesive tape, and peeling the excess portion 3A2 off from the release film 2. As a result, the inner portion 3A1 remaining on the release film 2 becomes the multiple adhesive film pieces 3 that are provided on the film 1. Thus, a film 1 with multiple adhesive film pieces 3 provided on the release film 2 is manufactured. In addition, the half-cut line of the release film 2 is formed on the surface 2a of the release film 2 on the side with the multiple adhesive film pieces 3 and becomes a groove 4 that extends along the outer edge 3a of each of the multiple adhesive film pieces 3. Therefore, in the film 1 manufactured in this manner, grooves 4 are formed on the surface 2a of the release film 2 on the side of the multiple adhesive film pieces 3, extending along the outer edge 3a of each of the multiple adhesive film pieces 3, and the width of the grooves 4 is 15 μm or more.

[0068] [Coiled body] As shown in Figure 2, the winding body 15 comprises a long (tape-like) film 1 and a winding core 14 around which the film 1 is wound. In other words, the winding body 15 is formed by winding the film 1 around the winding core 14.

[0069] The winding core 14 comprises a core material 14a and a pair of side plates 14b. The core material 14a is formed in a cylindrical shape. The film 1 is wound around the outer surface of the core material 14a. The pair of side plates 14b are attached to both ends of the core material 14a in the axial direction. The pair of side plates 14b support the film 1 from the left and right. The distance between the pair of side plates 14b is slightly wider than the width of the film 1.

[0070] [Connection structure] As shown in Figure 13, the connecting structure 16 comprises a first member 17 having a first adhesive surface 17a, a second member 18 having a second adhesive surface 18a, and an adhesive film piece 3 connecting the first adhesive surface 17a and the second adhesive surface 18a.

[0071] The first member 17 is, for example, a chip component such as an IC chip, LSI chip, resistor chip, or capacitor chip; a photoelectric conversion component such as an LED or image sensor; a piezoelectric conversion component such as a strain sensor, pressure sensor, acoustic component, or piezoelectric element; a circuit forming component such as a flexible printed circuit board; a thermal sensor such as a thermometer or heat sink; or a thermal management component. On the first member 17, the surface facing the second member 18 is the first bonding surface 17a. For example, a first electrode (not shown) for electrical conductivity with the second member 18 is arranged on the first bonding surface 17a.

[0072] The second member 18 is, for example, a light-transmitting substrate such as a glass substrate, polyimide substrate, polyamide-imide substrate, polyethylene terephthalate substrate, polycarbonate substrate, cycloolefin polymer (COP) substrate, polyethylene naphthalate substrate, glass-reinforced epoxy substrate, paper phenolic substrate, ceramic substrate, or laminate, or a silicon substrate. On the second member 18, the surface facing the first adhesive surface 17a of the first member 17 is the second adhesive surface 18a. For example, a second electrode (not shown) for electrical conductivity with the first member 17 is arranged on the second adhesive surface 18a.

[0073] Furthermore, there is no clear distinction between the first member 17 and the second member 18, and any member may be applied to each member.

[0074] The adhesive film piece 3 is the adhesive film piece 3 peeled off from the film 1 described above. The adhesive film piece 3 connects the first adhesive surface 17a and the second adhesive surface 18a with adhesive 6. If the adhesive film piece 3 has anisotropic conductivity due to the inclusion of conductive particles 7, the conductive particles 7 can make electrical contact between the first electrode of the first adhesive surface 17a and the second electrode of the second adhesive surface 18a.

[0075] [Manufacturing method for connecting structures] As shown in Figure 14, the method for manufacturing the connecting structure comprises a preparation step (S21) and a connection step (S22) performed after the preparation step (S21).

[0076] In the preparation step (S21), the film 1 described above is prepared. At this time, a wound body 15 on which the film 1 is wound is prepared as the film 1. Note that in the preparation step (S21), the film manufacturing method described above may be performed, or the film 1 manufactured by the film manufacturing method described above may be prepared.

[0077] As shown in Figure 15, the connection step (S22) comprises a position detection step (S31), an adhesive step (S32), and an overlapping step (S33).

[0078] In the position detection step (S31), first, the film 1 is unwound from the winding body 15. Then, as shown in Figure 16, the imaging device 33 detects the position of the adhesive film piece 3 on the film 1. At this time, the imaging device 33 may be positioned on the side of the adhesive film piece 3 relative to the release film 2, or on the opposite side of the adhesive film piece 3 relative to the release film 2. As shown in Figure 16, in this embodiment, the imaging device 33 is positioned on the opposite side of the adhesive film piece 3 relative to the release film 2. In this case, by using a light-transmitting release film 2, the imaging device 33 can detect the position of the adhesive film piece 3 on the film 1 from the release film 2 side.

[0079] In the application process (S32), the adhesive film piece 3 is attached to the first adhesive surface 17a based on the position detected in the position detection process (S31). Subsequently, the release film 2 is peeled off from the adhesive film piece 3 attached to the first adhesive surface 17a. In this process, the adhesive film piece 3 can be made easier to peel off from the release film 2 by heating and pressurizing it within a range that does not affect the degree of curing of the adhesive on the adhesive film piece 3. For example, the heating temperature may be 70°C, the heating time 1 second, and the pressure may be 1 MPa relative to the area of ​​the adhesive film piece 3.

[0080] In the overlapping step (S33), the first adhesive surface 17a and the second adhesive surface 18a are overlapped via the adhesive film piece 3. This temporarily connects the first adhesive surface 17a and the second adhesive surface 18a with the adhesive 6 of the adhesive film piece 3. Then, the first member 17 and the second member 18 are pressurized, and the adhesive 6 of the adhesive film piece 3 is cured by applying heat or light. This results in a connected structure 16 in which the first adhesive surface 17a and the second adhesive surface 18a are connected by the adhesive film piece 3. If the adhesive film piece 3 has anisotropic conductivity due to the inclusion of conductive particles 7, before curing the adhesive 6, the first member 17 and the second member 18 are pressurized to make electrical contact between the first member 17 and the second member 18 with the conductive particles 7 of the adhesive film piece 3. This manufactures the connected structure 16.

[0081] As described above, in the film 1 according to this embodiment, since a plurality of adhesive film pieces 3 are provided on the release film 2, each of the plurality of adhesive film pieces 3 tends to spread along the surface 2a of the release film 2. However, the surface 2a of the release film 2 on the side of the plurality of adhesive film pieces 3 is provided with grooves 4 that extend along the outer edge 3a of each of the plurality of adhesive film pieces 3, and the width of the grooves 4 is 15 μm or more. Therefore, the spreading of each of the plurality of adhesive film pieces 3 along the surface 2a of the release film 2 is prevented by the grooves 4, thereby suppressing each of the plurality of adhesive film pieces 3 from spreading beyond the grooves 4.

[0082] Furthermore, in this film 1, the grooves 4 are located outside the outer edge 3a of each of the multiple adhesive film pieces 3, which further suppresses the spreading of each of the multiple adhesive film pieces 3.

[0083] Furthermore, in this film 1, since the depth of the groove 4 is 10% or more of the thickness of the release film 2, the width of the groove 4 can be easily made 15 μm or more, and the path for each of the multiple adhesive film pieces 3 to cross the groove 4 can be made longer. This further suppresses the spreading of each of the multiple adhesive film pieces 3 beyond the groove 4.

[0084] Furthermore, in this film 1, the depth of the groove 4 is 85% or less of the thickness of the release film 2, which helps to suppress the tearing of the release film 2.

[0085] Furthermore, in this film 1, the depth of the groove 4 is 20% or more of the thickness of the adhesive film piece 3 surrounded by the groove 4, which allows each of the multiple adhesive film pieces 3 to have a longer path to cross the groove 4. This further suppresses the spreading of each of the multiple adhesive film pieces 3 beyond the groove 4.

[0086] Furthermore, in this film 1, the groove 4 can be easily formed because the depth of the groove 4 is 100% or less of the thickness of the adhesive film piece 3 surrounded by the groove 4.

[0087] Furthermore, in this film 1, the adhesive 6 forming each of the multiple adhesive film pieces 3 has a multilayer structure, which makes it easier for each of the multiple adhesive film pieces 3 to spread out. However, as mentioned above, since it has grooves 4 with a width of 15 μm or more, it is possible to suppress each of the multiple adhesive film pieces 3 from spreading beyond the grooves 4.

[0088] Furthermore, in this film 1, the degree of curing of the adhesive 6 forming each of the multiple adhesive film pieces 3, as measured by differential scanning calorimetry, is 80% or more at 150°C for 10 seconds, 80% or more at 160°C for 10 seconds, 80% or more at 170°C for 10 seconds, 80% or more at 180°C for 10 seconds, 80% or more at 200°C for 10 seconds, 80% or more at 210°C for 10 seconds, or 80% or more at 230°C for 10 seconds. This reduces the thermal effects on areas other than the connection points and appropriately suppresses each of the multiple adhesive film pieces 3 from spreading beyond the groove 4.

[0089] Furthermore, in this film 1, by using thermoplastic resins such as styrene resin-based and polyester resin-based resins, thermosetting resins such as epoxy resin-based, acrylic resin-based and silicone resin-based resins, mixtures of these thermoplastic resins and thermosetting resins, and photocurable resins as the adhesive 6 that forms each of the multiple adhesive film pieces 3, it is possible to appropriately suppress each of the multiple adhesive film pieces 3 from spreading beyond the groove 4.

[0090] Furthermore, in this film 1, the multiple adhesive film pieces 3 are spaced apart from each other, allowing the adhesive film pieces 3 to be attached to the bonding surface without affecting adjacent adhesive film pieces 3. This makes it easy to attach the adhesive film pieces 3 to the bonding surface.

[0091] Furthermore, in this film 1, the multiple adhesive film pieces 3 are spaced apart from the edges of the release film 2 in the width direction of the release film 2, which prevents the adhesive film pieces 3 from peeling off the release film 2 when the edges of the release film 2 come into contact with other components.

[0092] Furthermore, in this film 1, multiple adhesive film pieces 3 are arranged in a line along the longitudinal direction X of the release film 2, making it easy to attach the adhesive film pieces 3.

[0093] Furthermore, in this film 1, since at least one of the multiple adhesive film pieces 3 has a hole 3b, the adhesive film piece 3 can be properly attached to a portion of the film, for example, where there is a part in the center to which the adhesive film piece 3 should not be attached.

[0094] Furthermore, in this film 1, since multiple adhesive film pieces 3 have the same shape, the adhesive film pieces 3 can be efficiently attached to multiple adhesive surfaces of the same shape.

[0095] Furthermore, in this film 1, the adhesive film piece 3 is conductive, which allows electrical connection between the two members connected via the adhesive film piece 3.

[0096] Furthermore, in this film 1, since the adhesive film piece 3 contains conductive particles 7, conductivity can be easily imparted to the adhesive film piece 3.

[0097] In the winding body 15 according to this embodiment, the film 1 is wound around the winding core 14, so that winding pressure is generated on the film 1, pressing it toward the core material 14a (center) of the winding core 14. As a result, the adhesive film pieces 3, which are sandwiched between the inner layer side (winding core side) and the outer layer side (opposite side from the winding core) by the release film 2, are pressed from both the inner and outer layers by the release film 2 and attempt to deform, being pushed out along the surface 2a of the release film 2. However, the film 1 has grooves 4 formed on the surface 2a of the release film 2 on the side of the multiple adhesive film pieces 3, extending along the outer edge 3a of each of the multiple adhesive film pieces 3, and the width of the grooves 4 is 15 μm or more. As a result, the spreading of each of the multiple adhesive film pieces 3 along the surface 2a of the release film 2 is prevented by the grooves 4, thereby suppressing each of the multiple adhesive film pieces 3 from spreading beyond the grooves 4.

[0098] In the connecting structure 16 according to this embodiment, the first member 17 and the second member 18 are connected by the adhesive film piece 3, so that the protrusion of the adhesive film piece 3 from the first member 17 and the second member 18 is suppressed, thereby obtaining a connecting structure 16.

[0099] In the manufacturing method of the connecting structure according to this embodiment, the first adhesive surface 17a of the first member 17 and the second adhesive surface 18a of the second member 18 are connected via the adhesive film piece 3 of the film 1, so that the connecting structure 16 can be manufactured in which the protrusion of the adhesive film piece 3 from the first member 17 and the second member 18 is suppressed.

[0100] The present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention.

[0101] For example, in the above embodiment, an example of a connection step in a method for manufacturing a connecting structure was described, but the connection step can be implemented by any method as long as a film is used and the first member and the second member can be connected by adhesive film pieces of the film.

[0102] Furthermore, although the above embodiment described the film as having a two-layer structure in which a plurality of adhesive film pieces are provided on a release film, it may also have a three-layer structure in which a second release film is provided on a plurality of adhesive film pieces.

[0103] All or part of the above examples can be expressed by [1] to

[18] below, but are not limited to those described below.

[0104] [1] A film comprising a long release film, a plurality of adhesive film pieces provided on the release film, and grooves formed on the surface of the plurality of adhesive film pieces of the release film and extending along the outer edges of each of the plurality of adhesive film pieces, wherein the width of the grooves is 15 μm or more. [2] The film according to [1], wherein the groove is located outside the outer edge of each of the plurality of adhesive film pieces. [3] The film according to [1] or [2], wherein the depth of the groove is 10% or more of the thickness of the release film. [4] The depth of the groove is 85% or less of the thickness of the release film, the film according to any one of [1] to [3]. [5] The film according to any one of [1] to [4], wherein the depth of the groove is 20% or more of the thickness of the adhesive film piece surrounded by the groove among the plurality of adhesive film pieces. [6] The film according to any one of [1] to [5], wherein the depth of the groove is 100% or less of the thickness of the adhesive film piece surrounded by the groove among the plurality of adhesive film pieces. [7] The adhesive forming each of the plurality of adhesive film pieces is a film according to any one of [1] to [6] having a multilayer structure. [8] The film according to any one of [1] to [7], wherein the degree of curing of the adhesive forming each of the plurality of adhesive film pieces by differential scanning calorimetry is 80% or more under the condition of 150°C for 10 seconds. [9] The aforementioned plurality of adhesive film pieces are spaced apart from each other, as described in any one of [1] to [8].

[10] The film according to any one of [1] to [9], wherein the plurality of adhesive film pieces are spaced apart from the edges of the release film in the width direction of the release film.

[11] The film according to any one of [1] to

[10] , wherein the plurality of adhesive film pieces are arranged in a row in the longitudinal direction of the release film.

[12] At least one of the plurality of adhesive film pieces has a hole. The film described in any one of [1] to

[11] .

[13] The aforementioned multiple adhesive film pieces are of the same shape, and are the films described in any one of [1] to

[12] .

[14] The adhesive film piece is a conductive film as described in any one of [1] to

[13] .

[15] The adhesive film piece is the film according to

[14] , which contains conductive particles.

[16] A winding body comprising a film described in any one of [1] to

[15] and a core around which the film is wound.

[17] A connecting structure comprising a first member having a first adhesive surface, a second member having a second adhesive surface, and an adhesive film piece according to any one of [1] to

[15] for connecting the first adhesive surface and the second adhesive surface.

[18] A method for manufacturing a connecting structure, comprising: a preparation step of preparing a film described in any one of [1] to

[15] ; and a connecting step of connecting the first adhesive surface of a first member and the second adhesive surface of a second member via the adhesive film piece of the film.

[0105] [Examples] Next, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments.

[0106] (Example 1) An adhesive film layer containing adhesive and conductive particles was formed over the entire surface of a long release film. Next, using a roll cutter with a pinnacle blade formed on its outer surface, the adhesive film layer formed on the release film was cut along the outer edge line forming the outer edge of the multiple adhesive film pieces to be provided on the film, and the release film was half-cut. Next, along the cut outline, the excess portion of the adhesive film layer that was not the multiple adhesive film pieces to be provided on the film was peeled off from the release film. As a result, the film of Example 1 was obtained in which multiple adhesive film pieces were provided on the release film, and grooves were formed on the surface of the multiple adhesive film pieces on the release film side, extending along the outer edge of each of the multiple adhesive film pieces. Then, a winding body was prepared by winding the film of Example 1 onto a core with a tension of 1.5 N, the film was unwound from the winding body, the film was cut at an arbitrary position, and this cut surface was imaged with a scanning electron microscope as the observation surface. The scanning electron microscope used was an S8020 manufactured by Hitachi High-Tech Corporation. A schematic diagram of the captured image is shown in Figure 17.

[0107] As shown in Figure 17, on the observation surface, the groove width was 25.8 μm, the groove depth was 28.6 μm, the thickness of the release film was 53.6 μm, the ratio of groove depth to release film thickness was 53%, and the thickness of the adhesive film piece was 20.4 μm. The condition of the adhesive film piece and release film in the film of Example 1 was then observed. In the observation of the condition of the adhesive film piece, A was defined as the case where the adhesive film piece did not extend beyond the groove, and B was defined as the case where the adhesive film piece extended beyond the groove. In the observation of the condition of the release film, A was defined as the case where the release film was not broken, and B was defined as the case where the release film was broken. The results are shown in Figure 22.

[0108] (Example 2) The film of Example 2 was obtained using the same method as in Example 1. Furthermore, a winding body was prepared by winding the film of Example 2 onto a core using the same method as in Example 1. The film was unwound from the winding body, cut at an arbitrary position, and the cut surface was used as the observation surface and imaged with a scanning electron microscope. A schematic diagram of the captured image is shown in Figure 18.

[0109] As shown in Figure 18, on the observation surface, the groove width was 30.5 μm, the groove depth was 40.8 μm, the thickness of the release film was 52.4 μm, the ratio of groove depth to release film thickness was 78%, and the thickness of the adhesive film piece was 21.3 μm. Then, similar to Example 1, the condition of the adhesive film piece and release film in the film of Example 2 was observed. The results are shown in Figure 22.

[0110] (Example 3) The film of Example 3 was obtained using the same method as in Example 1. Furthermore, a winding body was prepared by winding the film of Example 3 onto a core using the same method as in Example 1. The film was unwound from the winding body, cut at an arbitrary position, and the cut surface was used as the observation surface and imaged with a scanning electron microscope. A schematic diagram of the captured image is shown in Figure 19.

[0111] As shown in Figure 19, on the observation surface, the groove width was 34.6 μm, the groove depth was 51.6 μm, the release film thickness was 62.9 μm, the ratio of groove depth to release film thickness was 82%, and the adhesive film piece thickness was 28.3 μm. Then, similar to Example 1, the condition of the adhesive film piece and release film in the film of Example 3 was observed. The results are shown in Figure 22.

[0112] (Example 4) The film of Example 4 was obtained using the same method as in Example 1. Furthermore, a winding body was prepared by winding the film of Example 4 onto a core using the same method as in Example 1. The film was unwound from the winding body, cut at an arbitrary position, and the cut surface was used as the observation surface and imaged with a scanning electron microscope. A schematic diagram of the captured image is shown in Figure 20.

[0113] As shown in Figure 20, on the observation surface, the groove width was 35.0 μm, the groove depth was 52.4 μm, the thickness of the release film was 59.5 μm, the ratio of groove depth to release film thickness was 88%, and the thickness of the adhesive film piece was 29.4 μm. Then, similar to Example 1, the condition of the adhesive film piece and release film in the film of Example 4 was observed. The results are shown in Figure 22.

[0114] (Comparative Example 1) A film of Comparative Example 1 was obtained using the same method as in Example 1. A winding body was then prepared by winding the film of Comparative Example 1 onto a core using the same method as in Example 1. The film was unwound from the winding body, cut at an arbitrary position, and the cut surface was used as the observation surface for imaging with a scanning electron microscope. A schematic diagram of the captured image is shown in Figure 21.

[0115] As shown in Figure 21, on the observation surface, the groove width was 11.0 μm, the groove depth was 4.37 μm, the release film thickness was 50.2 μm, the ratio of groove depth to release film thickness was 9%, and the adhesive film piece thickness was 26.4 μm. Then, similar to Example 1, the condition of the adhesive film piece in the film of Comparative Example 1 was observed. The results are shown in Figure 22.

[0116] (Consideration) As shown in Figure 22, in Comparative Example 1, where the groove width was less than 15 μm, the adhesive film fragments spread beyond the grooves. However, in Examples 1 to 4, where the groove width was 15 μm or more, the adhesive film fragments did not spread beyond the grooves. Therefore, it can be inferred that by making the groove width 15 μm or more, the spreading of the adhesive film fragments beyond the grooves can be suppressed.

[0117] Furthermore, in Example 4, where the ratio of groove depth to release film thickness was greater than 85%, the release film broke, but in Examples 1-3, where the ratio of groove depth to release film thickness was 85% or less, the release film did not break. Therefore, it can be inferred that breaking of the release film can be suppressed by setting the ratio of groove depth to release film thickness to 85% or less. [Industrial applicability]

[0118] The present invention can be used, for example, as a film, a wound body, a connecting structure, and a method for manufacturing the connecting structure. [Explanation of symbols]

[0119] 1...Film, 2...Release film, 2a...Front surface, 2b...Back surface, 3...Adhesive film piece, 3a...Outer edge, 3A...Adhesive film layer, 3A1...Inner portion, 3A2...Margin portion, 3b...Hole, 3B...Outer edge line, 4...Groove, 6...Adhesive, 7...Conductive particles, 8...Conductive adhesive area, 9...Non-conductive adhesive area, 14...Core, 14a...Core material, 14b...Side plate, 15...Winding body, 16...Connecting structure, 17...First member, 17a...First adhesive surface, 18...Second member, 18a...Second adhesive surface, 33...Imaging device, X...Longitudinal direction, Y...Width direction, Z...Thickness direction.

Claims

1. A long roll of release film, A plurality of adhesive film pieces provided on the release film, The release film comprises grooves formed on the surface of one side of the plurality of adhesive film pieces and extending along the outer edge of each of the plurality of adhesive film pieces, The width of the groove is 15 μm or more. The depth of the groove is 20% or more of the thickness of the adhesive film piece surrounded by the groove among the plurality of adhesive film pieces. film.

2. The groove is located on the outside of the outer edge of each of the plurality of adhesive film pieces. The film according to claim 1.

3. The depth of the groove is 10% or more of the thickness of the release film. The film according to claim 1 or 2.

4. The depth of the groove is 85% or less of the thickness of the release film. The film according to claim 3.

5. The depth of the groove is 100% or less of the thickness of the adhesive film piece surrounded by the groove among the plurality of adhesive film pieces. The film according to claim 1 or 2.

6. The adhesive forming each of the aforementioned plurality of adhesive film pieces has a multilayer structure. The film according to claim 1 or 2.

7. The degree of curing of the adhesive forming each of the aforementioned plurality of adhesive film pieces, as measured by differential scanning calorimetry, is 80% or more under the condition of 150°C for 10 seconds. The film according to claim 1 or 2.

8. The aforementioned multiple adhesive film pieces are spaced apart from each other. The film according to claim 1 or 2.

9. The plurality of adhesive film pieces are spaced apart from the edges of the release film in the width direction of the release film. The film according to claim 1 or 2.

10. The plurality of adhesive film pieces are arranged in a line along the longitudinal direction of the release film. The film according to claim 1 or 2.

11. At least one of the plurality of adhesive film pieces has a hole. The film according to claim 1 or 2.

12. The aforementioned multiple adhesive film pieces are the same shape. The film according to claim 1 or 2.

13. The adhesive film piece has conductivity, The film according to claim 1 or 2.

14. The adhesive film piece contains conductive particles, The film according to claim 13.

15. A film according to claim 1 or 2, A winding core around which the aforementioned film is wound, comprising A coiled body.

16. A first member having a first adhesive surface, A second member having a second adhesive surface, The adhesive film piece according to claim 1 or 2 connects the first adhesive surface and the second adhesive surface, A connection structure.

17. A preparation step for preparing the film according to claim 1 or 2, The device includes a connecting step of connecting the first adhesive surface of the first member and the second adhesive surface of the second member via the adhesive film piece of the film. A method for manufacturing a connecting structure.

Images