CN114196334A

CN114196334A - Adhesive tape, method for producing same, and reel for adhesive film

Info

Publication number: CN114196334A
Application number: CN202210037591.4A
Authority: CN
Inventors: 立泽贵; 田中胜
Original assignee: Showa Denko KK
Current assignee: Resonac Holdings Corp
Priority date: 2016-01-29
Filing date: 2017-01-17
Publication date: 2022-03-18
Also published as: KR20180111858A; JPWO2017130789A1; TW201739864A; CN114262577A; CN108603078A; TWI750149B; WO2017130789A1; JP6988482B2

Abstract

The invention provides an adhesive tape, a method for manufacturing the same, and a reel for adhesive film. The adhesive tape comprises a tape-shaped base material and an adhesive film, wherein the adhesive film is formed by sequentially laminating a first non-conductive adhesive layer, a conductive adhesive layer containing conductive particles, and a second non-conductive adhesive layer, the thickness T1 of the first non-conductive adhesive layer and the thickness T of the conductive adhesive layer satisfy the following formula (1), T1 < T … (1), the thickness T2 of the T1 and the thickness T2 of the second non-conductive adhesive layer satisfy T1 not more than 0.5 x T2, the T is 1.5-4 μm, the T1 is 0.5-2.5 μm, and the T2 is 7-10 μm.

Description

Adhesive tape, method for producing same, and reel for adhesive film

The present application is a divisional application of a chinese patent application having an application date of 2017, 1/17, and an application number of 201780008489.9, entitled "adhesive film and method for manufacturing the same, adhesive tape, and roll for adhesive film".

Technical Field

The invention relates to an adhesive film and a manufacturing method thereof, an adhesive tape and a reel for the adhesive film.

Background

Conventionally, as a connecting material for electrically connecting members to be connected having a plurality of electrodes to each other to manufacture a circuit connected body, an anisotropic Conductive film (acf) has been used. The anisotropic conductive film is a connecting material that, when a semiconductor element such as an IC or LSI, a package, or the like is connected to a substrate such as a printed wiring board, a glass substrate for an LCD, or a flexible printed circuit board, electrically and mechanically fixes the electrodes facing each other so as to maintain a conductive state and to maintain insulation between adjacent electrodes. As a connection material, a Non-Conductive film (NCF) or the like is known in addition to an anisotropic Conductive film.

The connecting material includes, for example, an adhesive component containing a thermosetting resin or the like and conductive particles incorporated as needed in the anisotropic conductive film, and is formed in a film shape as an adhesive layer on a base material such as a polyethylene terephthalate (PET) film. Further, an adhesive film may be used in a state of a roll obtained by cutting a film-like original plate into a tape having a width suitable for the application, winding the tape around a core to form a roll body (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2003-34468

Disclosure of Invention

Problems to be solved by the invention

However, in the case of connecting the driver ICs and the like to the LCD module using the connecting material, a portion of the connecting material that originally contributes to the effective connection between the circuit members is about half or less of the entire LCD module, but in terms of work efficiency and equipment investment, the connecting material is generally first attached to the entire LCD module, and then the driver ICs and the like are mounted. However, in recent years, there has been a trend to reduce the amount of connecting material used in order to reduce the manufacturing cost of LCDs. For this reason, the following techniques are being studied: when a COF, an FPC or the like is connected to an LCD module, a connection material is first attached to the COF or FPC side and then mounted on the LCD module side, so that the amount of the connection material used is reduced and the cost is reduced.

On the other hand, in the case of using an LCD module having a high-definition circuit, it is desirable to use a connecting material formed of two layers, i.e., a non-conductive adhesive layer and a conductive adhesive layer containing conductive particles, from the viewpoint of short-circuiting between circuits and capturing efficiency of conductive particles. In general, a connecting material having a two-layer structure is obtained by forming a non-conductive adhesive layer on a base material and further forming a conductive adhesive layer on the non-conductive adhesive layer. However, in the case of adopting a process of first attaching a connecting material composed of two layers on the COF or FPC side, the surface on the non-conductive adhesive layer side is attached toward the LCD module side, and therefore, there is a problem that sufficient connection characteristics cannot be obtained.

In order to solve the above-described problems, the present inventors have studied a process of attaching a two-layer connecting material to a COF or FPC side and then mounting the two-layer connecting material on an LCD module, in which a conductive adhesive layer is first formed on a base material, and a non-conductive adhesive layer is further formed on the conductive adhesive layer to obtain a two-layer connecting material. However, in this case, it is found that a phenomenon (so-called blocking) phenomenon, in which the conductive adhesive layer is transferred to the base material, occurs when the base material is peeled from the connecting material at the time of circuit connection. If the sticking phenomenon occurs, a necessary amount of the conductive adhesive cannot be disposed at a predetermined position on the member to be connected, and the connection reliability (electrical connection or mechanical fixation) of the connection portion may become insufficient.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an adhesive film which has a conductive adhesive layer and a non-conductive adhesive layer, can suppress the occurrence of blocking phenomenon, and can obtain excellent connection reliability when used for manufacturing a circuit connection body, a method for manufacturing the adhesive film, an adhesive tape, and a reel for the adhesive film.

Means for solving the problems

In one embodiment of the present invention, an adhesive film is provided in which a first nonconductive adhesive layer, a conductive adhesive layer containing conductive particles, and a second nonconductive adhesive layer are laminated in this order, and the thickness T1 of the first nonconductive adhesive layer and the thickness T of the conductive adhesive layer satisfy the following formula (1).

T1＜T…(1)

In another aspect of the present invention, there is provided a method for producing an adhesive film, including the steps of: and a step of obtaining an adhesive film by sequentially laminating a first nonconductive adhesive layer, a conductive adhesive layer containing conductive particles, and a second nonconductive adhesive layer, wherein the thickness T1 of the first nonconductive adhesive layer and the thickness T of the conductive adhesive layer satisfy the following formula (1).

T1＜T…(1)

T1 and the average particle diameter r of the conductive particles preferably satisfy the following formula (2).

T1≤0.8×r…(2)

T1 and the thickness T2 of the second nonconductive adhesive layer preferably satisfy the following formula (3).

T1≤T2…(3)

In another aspect of the present invention, there is provided an adhesive film containing conductive particles, the adhesive film including, in order in a thickness direction of the adhesive film, a first non-conductive region where no conductive particles are present, a conductive region where conductive particles are present, and a second non-conductive region where no conductive particles are present, wherein a length L1 of the first non-conductive region in the thickness direction of the adhesive film and a length L of the conductive region in the thickness direction of the adhesive film satisfy the following formula (4).

L1＜L…(4)

L1 and the average particle diameter r of the conductive particles preferably satisfy the following formula (5).

L1≤0.8×r…(5)

L1 and the length L2 of the second nonconductive region in the thickness direction of the adhesive film preferably satisfy the following formula (6).

L1≤L2…(6)

In another aspect of the present invention, there is provided an adhesive tape including a tape-shaped base material and the adhesive film provided on one surface of the base material.

In another aspect of the present invention, there is provided a reel for an adhesive film, including the adhesive tape and a core around which the adhesive tape is wound.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, an adhesive film, a method for producing the adhesive film, an adhesive tape, and a reel for an adhesive film can be provided, which have a conductive adhesive layer and a non-conductive adhesive layer, can suppress the occurrence of blocking phenomenon, and can obtain excellent connection reliability when used for producing a circuit connection body.

Drawings

Fig. 1 is a schematic sectional view showing one embodiment of an adhesive film.

Fig. 2 is a schematic cross-sectional view showing another embodiment of the adhesive film.

Fig. 3 is a perspective view showing one embodiment of a roll for an adhesive film.

Fig. 4 is an enlarged cross-sectional view of the adhesive tape in the roll for adhesive film shown in fig. 3.

Fig. 5 is a schematic cross-sectional view showing an embodiment of a method for manufacturing a circuit-connected body.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the embodiments described below. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, for the sake of convenience of the drawings, the dimensional ratios of the drawings are not necessarily consistent with the contents of the description.

[ adhesive film (first embodiment) ]

Fig. 1 is a schematic cross-sectional view showing an adhesive film according to a first embodiment. As shown in fig. 1, the adhesive film 1 is formed by laminating a first nonconductive adhesive layer 2, a conductive adhesive layer 3, and a second nonconductive adhesive layer 4 in this order.

The first and second nonconductive

adhesive layers

2 and 4 are composed of

adhesive components

2a and 4a, respectively. The

adhesive components

2a and 4a constituting the first and second nonconductive

adhesive layers

2 and 4 may be the same as or different from each other.

The

adhesive components

2a and 4a can be widely used as long as they are cured by heat or light, and for example, an epoxy adhesive or an acrylic adhesive can be used. The

adhesive components

2a and 4a are preferably crosslinkable components from the viewpoint of excellent heat resistance and moisture resistance of the cured product. Among these, an epoxy adhesive containing an epoxy resin as a thermosetting resin as a main component is preferable in terms of being curable in a short time, having good connection workability, and having excellent adhesion. In addition, the epoxy adhesive is preferable because transfer of the adhesive component to the substrate can be suppressed, compared with the epoxy adhesive, for example, in the case of forming an adhesive tape by providing an adhesive film on the substrate (described in detail later). As the

adhesive components

2a and 4a, for example, a radical curing adhesive as described in international publication No. 98/44067 can be used.

Specific examples of the epoxy adhesive include adhesives containing, as a main component, a high molecular weight epoxy resin (for example, having a weight average molecular weight of 10000 to 100000), a solid epoxy resin or a liquid epoxy resin, or a modified epoxy resin obtained by modifying these epoxy resins with urethane, polyester, acrylic rubber, nitrile rubber (NBR), synthetic linear polyamide, or the like. The epoxy adhesive may further contain additives such as a curing agent, a catalyst, a coupling agent, and a filler, in addition to the epoxy resin.

Specific examples of the acrylic adhesive include adhesives containing, as a main component, an acrylic resin (homopolymer or copolymer) containing at least one of acrylic acid, acrylic ester, methacrylic ester, and acrylonitrile as a monomer component. The acrylic adhesive may further contain additives such as a curing agent, a catalyst, a coupling agent, and a filler, in addition to the acrylic resin.

In the case of connecting circuit members to each other, the

adhesive components

2a and 4a preferably contain a component that exhibits a relaxation action of internal stress from the viewpoint of suppressing warpage of the circuit members caused by a difference in linear expansion coefficient between the two circuit members. Specifically, the

adhesive components

2a and 4a preferably contain acrylic rubber, an elastomer component, and the like.

The conductive adhesive layer 3 contains an adhesive component 3a and conductive particles 5. The adhesive component 3a may be the same as the

adhesive components

2a and 4a described as the adhesive components constituting the first and second non-conductive

adhesive layers

2 and 4, and may be the same as or different from the

adhesive components

2a and 4a constituting the first and second non-conductive

adhesive layers

2 and 4, respectively.

The conductive particles 5 are dispersed in the adhesive component 3 a. Examples of the conductive particles 5 include metal particles such as Au, Ag, Pt, Ni, Cu, W, Sb, Sn, and solder, and particles of conductive carbon. Alternatively, the conductive particles 5 may be coated conductive particles obtained by coating a particle such as non-conductive glass, ceramic, or plastic as a core with the metal or conductive carbon. The conductive particles 5 may be insulation-coated conductive particles whose surfaces are coated with an insulation layer. From the viewpoint of improving the insulation between adjacent electrodes, the conductive adhesive layer 3 may further contain insulating particles in addition to the conductive particles 5.

The content of the conductive particles 5 is, for example, 0.1 to 30 parts by volume, preferably 0.1 to 10 parts by volume, relative to 100 parts by volume of the adhesive component 3a contained in the conductive adhesive layer 3. If the content is 0.1 parts by volume or more, the connection resistance between the opposing electrodes tends to decrease, and if it is 30 parts by volume or less, short-circuiting between adjacent electrodes can be suppressed.

In the adhesive film 1, the thickness T1 of the first nonconductive adhesive layer 2 and the thickness T of the conductive adhesive layer 3 satisfy the following formula (1).

T1＜T…(1)

From the viewpoint of more excellent capture efficiency of the conductive particles 5 in circuit connection, T1 and T preferably satisfy the relational expression of T1 < 0.9 × T, more preferably T1 < 0.8 × T, and further preferably T1 < 0.7 × T.

In the adhesive film 1, the thickness T1 of the first nonconductive adhesive layer 2 and the average particle diameter r of the conductive particles 5 preferably satisfy the following formula (2) from the viewpoint that the capture efficiency of the conductive particles 5 at the time of circuit connection is excellent and the connection resistance can be further reduced.

T1≤0.8×r…(2)

From the same viewpoint, T1 and r more preferably satisfy the relation T1. ltoreq.0.7 × r.

In the adhesive film 1, the thickness T1 of the first non-conductive adhesive layer 2 and the thickness T2 of the second non-conductive adhesive layer 4 preferably satisfy the following formula (3) from the viewpoint of excellent transferability to a circuit member and filling property of a space between circuit members at the time of circuit connection.

T1≤T2…(3)

From the same viewpoint as T1 and T2, T1. ltoreq.0.5 XT 2 is more preferably satisfied, T1. ltoreq.0.4 XT 2 is more preferably satisfied, and T1. ltoreq.0.3 XT 2 is particularly preferably satisfied.

When the thickness of the first non-conductive adhesive layer 2, the conductive adhesive layer 3, or the second non-conductive adhesive layer 4 is not uniform, the maximum value of the thickness of each layer is the thickness T1, the thickness T, or the thickness T2.

The average particle diameter of the conductive particles in the present invention is defined as follows. That is, the conductive particle image was observed at 3000 times by a Scanning Electron Microscope (SEM), and a plurality of conductive particles were randomly selected. In this case, in order to determine the average particle diameter with high accuracy, it is preferable to select 30 or more conductive particles. The maximum diameter and the minimum diameter of the selected conductive particles are measured, and the square root of the product of the maximum diameter and the minimum diameter is defined as the particle diameter of the conductive particles. The average particle diameter is defined as a value obtained by dividing the particle diameter calculated in this way by the number of particles measured.

The thickness T1 of the first non-conductive adhesive layer 2, the thickness T of the conductive adhesive layer 3, the thickness T2 of the second non-conductive adhesive layer 4, and the average particle diameter r of the conductive particles 5 preferably satisfy the above-described relationship, and the specific thickness or average particle diameter thereof is not particularly limited.

The thickness T1 of the first nonconductive adhesive layer 2 may be, for example, 0.5 μm or more, or 1 μm or more, and may be, for example, 2.5 μm or less, or 2 μm or less.

The thickness T of the conductive adhesive layer 3 may be, for example, 1.5 μm or more, or 2 μm or more, or, for example, 4 μm or less, or 3.5 μm or less.

The thickness T2 of the second nonconductive adhesive layer 4 may be, for example, 5 μm or more, or 7 μm or more, for example, 10 μm or less, or 9 μm or less.

The average particle diameter r of the conductive particles 5 may be, for example, 2 μm or more, or 3 μm or more, and may be, for example, 5 μm or less, or 4 μm or less.

The adhesive film 1 may further include a base material (not shown) on the surface of the first non-conductive adhesive layer 2 opposite to the conductive adhesive layer 3 or on the surface of the second non-conductive adhesive layer 4 opposite to the conductive adhesive layer 3. The thickness of the substrate may be, for example, 4 to 200 μm.

The substrate may be, for example, a substrate formed of polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber, liquid crystal polymer, or the like. The surface of the base material to which the first or second nonconductive adhesive layer is bonded may be subjected to a mold release treatment.

[ adhesive film (second embodiment) ]

Fig. 2 is a schematic cross-sectional view showing an adhesive film according to a second embodiment. As shown in fig. 2, the adhesive film 11 contains an adhesive component 11a and conductive particles 5. The adhesive film 11 includes, in order in the thickness direction of the adhesive film 11, a first non-conductive region R1 where the conductive particles 5 are not present, a conductive region R where the conductive particles 5 are present, and a second non-conductive region R2 where the conductive particles 5 are not present.

The adhesive component 11a may be the same adhesive component as the

adhesive components

2a, 3a, and 4a described in the first embodiment, and the conductive particles 5 may be the same conductive particles as the conductive particles 5 described in the first embodiment. The adhesive composition 11a may have a uniform composition throughout the adhesive film 11, or may have a different composition depending on the position of the adhesive film 11. For example, the adhesive component 11a may have different compositions in each of the first non-conductive region R1, the conductive region R, and the second non-conductive region R2.

The conductive region R is defined as a region between a first tangential plane which is a plane in contact with the conductive particles 5 and substantially parallel to the surface 11b of the adhesive film 11 on the first non-conductive region R1 side and which is present at the shortest distance from the surface 11b, and a second tangential plane which is a plane in contact with the conductive particles 5 and substantially parallel to the surface 11c of the adhesive film 11 on the second non-conductive region R2 side and which is present at the shortest distance from the surface 11 c.

The first non-conductive region R1 is defined as a region other than the conductive region R, which extends in the thickness direction of the adhesive film 11 from the first tangential plane toward the surface 11b of the adhesive film 11 on the first non-conductive region R1 side.

The second nonconductive region R2 is defined as a region other than the conductive region R, extending from the second cut plane toward the surface 11c of the adhesive film 11 on the second nonconductive region R2 side in the thickness direction of the adhesive film 11.

In the adhesive film 11, the length L1 of the first non-conductive region R1 and the length L of the conductive region R satisfy the following formula (4).

L1＜L…(4)

L1 and L preferably satisfy the relational expression L1 < 0.9 × L, more preferably L1 < 0.8 × L, and further preferably L1 < 0.7 × L, from the viewpoint of further improving the capture efficiency of the conductive particles 5 in circuit connection.

In the adhesive film 11, the length L1 of the first nonconductive region R1 and the average particle diameter R of the conductive particles 5 preferably satisfy the following formula (5) from the viewpoint that the conductive particles 5 are excellent in capture efficiency at the time of circuit connection and the connection resistance can be further reduced.

L1≤0.8×r…(5)

From the same viewpoint, L1 and r more preferably satisfy the relational expression L1. ltoreq.0.7 Xr.

In the adhesive film 11, the length L1 of the first non-conductive region R1 and the length L2 of the second non-conductive region R2 preferably satisfy the following formula (6) from the viewpoint of excellent transferability to a circuit member and filling ability of a space between circuit members at the time of circuit connection.

L1≤L2…(6)

From the same viewpoint as L1 and L2, L1 is more preferably not more than 0.5 XL 2, L1 is more preferably not more than 0.4 XL 2, and L1 is more preferably not more than 0.3 XL 2.

It is preferable that the length L1 of the first nonconductive region R1, the length L of the conductive region R, the length L2 of the second nonconductive region R2, and the average particle diameter R of the conductive particles 5 each satisfy the above-described relationship, and specific lengths or average particle diameters thereof are not particularly limited.

The length L1 of the first nonconductive region R1 may be, for example, greater than or equal to 0.5 μm, or greater than or equal to 1 μm, and may be, for example, less than or equal to 2.5 μm, or less than or equal to 2 μm.

The length L of the conductive region R may be, for example, 1.5 μm or more, or 2 μm or more, and may be, for example, 4 μm or less, or 3.5 μm or less.

The length L2 of the second nonconductive region R2 may be, for example, greater than or equal to 5 μm, or greater than or equal to 7 μm, and may be, for example, less than or equal to 10 μm, or less than or equal to 9 μm.

The adhesive film 11 may further include a region where conductive particles are present or a region where conductive particles are not present on the opposite side of the first nonconductive region R1 from the conductive region R.

[ method for producing adhesive film ]

The

adhesive films

1 and 11 according to the first and second embodiments are obtained, for example, by laminating a first nonconductive adhesive layer 2, a conductive adhesive layer 3 containing conductive particles 5, and a second nonconductive adhesive layer 4 in this order.

Specifically, for example, the

adhesive films

1 and 11 can be obtained by first laminating the first non-conductive adhesive layer 2 and the conductive adhesive layer 3 using a laminator or the like to obtain a laminate, and then further laminating the second non-conductive adhesive layer 4 on the conductive adhesive layer 3 side of the laminate in the same manner. Alternatively, the

adhesive films

1 and 11 can also be obtained by first laminating the conductive adhesive layer 3 and the second non-conductive adhesive layer 4 using a laminator or the like to obtain a laminate, and then further laminating the first non-conductive adhesive layer 2 on the conductive adhesive layer 3 side of the laminate in the same manner.

Each of the first non-conductive adhesive layer 2, the conductive adhesive layer 3, and the second non-conductive adhesive layer 4 is produced, for example, by the following method. First,

adhesive components

2a and 4a or adhesive component 3a and conductive particles 5 are dissolved in a solvent to prepare a coating solution. Next, the coating liquid is applied to, for example, a surface of the base material subjected to the mold release treatment, and dried at, for example, an activation temperature (for example, 100 ℃ or lower) of the curing agent contained in the

adhesive components

2a, 3a, and 4a or lower, and the solvent is removed to obtain each layer. The solvent may be an aromatic hydrocarbon solvent, an oxygen-containing solvent, or the like. The boiling point of the solvent may be 150 ℃ or lower, or 60 to 150 ℃ or 70 to 130 ℃.

The thickness T1 of the first non-conductive adhesive layer 2, the thickness T of the conductive adhesive layer 3, the thickness T2 of the second non-conductive adhesive layer 4, and the average particle diameter r of the conductive particles 5 used in this manufacturing method preferably satisfy the relationships of the expressions (1), (2), and (3) described in the first embodiment.

[ adhesive tape and reel for adhesive film ]

Fig. 3 is a perspective view showing one embodiment of a roll for an adhesive film. As shown in fig. 3, the roll 21 for adhesive film includes a cylindrical winding core 22 and disk-shaped side plates 23 provided on both end surfaces in the axial direction of the winding core 22. A long adhesive tape 24 is wound around the outer surface 22a of the core 22, and the adhesive tape 24 becomes a wound body. The adhesive tape 24 includes a tape-shaped base material 25 and an adhesive film 26 provided on one surface of the base material 25. The inner surface of the winding core 22 is a shaft hole 22b, and the shaft hole 22b is used for mounting to a rotating shaft of a pressure bonding device used for circuit connection, for example. The outer diameter of the winding core 22 is, for example, 4 to 15cm from the viewpoint of excellent workability.

Fig. 4 is an enlarged cross-sectional view of the adhesive tape 24 in the roll 21 for adhesive film shown in fig. 3. As shown in fig. 4 (a), the adhesive tape 24A includes a tape-shaped base material 25 and the adhesive film 1 according to the first embodiment, which is the adhesive film 26 provided on one surface of the base material 25.

As shown in fig. 4 (B), in another embodiment, the adhesive tape 24B includes a tape-shaped base material 25 and the adhesive film 11 according to the second embodiment, which is the adhesive film 26 provided on one surface of the base material 25.

The length of the substrate 25 is, for example, 1 to 400m, preferably 50 to 300 m. The thickness of the substrate 25 is, for example, 4 to 200 μm, preferably 20 to 100 μm. The width of the substrate 25 is preferably the same as the width of the

adhesive films

1 and 11 or wider than the width of the

adhesive films

1 and 11, and specifically, for example, 0.5 to 30mm, preferably 0.5 to 3.0 mm. The length, thickness and width of the base material 25 are not limited to the above ranges.

As the substrate 25, for example, a tape-shaped substrate formed of polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber, liquid crystal polymer, or the like can be used. The material constituting the substrate 25 is not limited thereto. The surface to be bonded between the substrate 25 and the adhesive film 26 may be subjected to a release treatment.

The width of the adhesive film 26 may be adjusted according to the use purpose, and is, for example, 0.5 to 5mm, preferably 0.5 to 3.0 mm.

In the adhesive film roll 21, the first nonconductive adhesive layer 2 or the first nonconductive region R1 is provided between the base material 25 of the

adhesive tapes

24A and 24B and the conductive adhesive layer 3, or between the base material 25 of the

adhesive tapes

24A and 24B and the conductive region R, so that when the adhesive film 26 is peeled off from the base material 25 and used for circuit connection, transfer (blocking phenomenon) of the conductive adhesive layer 3 or the conductive region R to the base material 25 can be suppressed.

In the above embodiment, the adhesive tape 24 is used in the form of the roll 21 for adhesive film, but the adhesive tape 24 may be used in a single piece form (a form cut into a desired size and shape in advance), for example.

[ Circuit connection body and method for manufacturing the same ]

A circuit connection body manufactured using the adhesive tape 24 will be described. Fig. 5 is a schematic cross-sectional view showing an embodiment of a method for manufacturing a circuit-connected body.

First, as shown in fig. 5 (a), a first circuit member 33 including a first circuit substrate 31 and first circuit electrodes 32 formed on a main surface 31a of the first circuit substrate 31 is prepared. Next, the adhesive tape 24A is placed on the first circuit member 33 so that the first circuit electrodes 32 of the first circuit member 33 face the second nonconductive adhesive layer 4 of the adhesive tape 24A.

Specific examples of the first circuit member 33 include an FPC board, a COF board, and the like. These circuit components generally have a plurality of circuit electrodes. The first circuit electrode 32 may be formed of one or more selected from gold, silver, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, and Indium Tin Oxide (ITO). The material of the plurality of first circuit electrodes 32 may be the same or different.

In the case of using the roll 21 for the adhesive film, for example, the roll 21 for the adhesive film may be attached to a rotation shaft of the pressure bonding apparatus, the adhesive tape 24A may be pulled out from the roll 21 for the adhesive film so that the second nonconductive adhesive layer 4 of the adhesive tape 24A faces the first circuit electrode 32 of the first circuit member 33, and then the adhesive tape 24A may be cut into a predetermined length and placed on the first circuit member 33.

Next, the first circuit member 33 and the adhesive tape 24A are pressed in the directions of arrows a and B, and the adhesive film 26 is temporarily attached to the first circuit member 33. The pressure at this time is not particularly limited as long as it is within a range that does not damage the first circuit member 33, and is preferably, for example, 0.1 to 30.0 MPa. In the temporary connection, pressure may be applied while heating. The heating temperature in this case may be a temperature at which the adhesive film 1 is not substantially cured, and is preferably 50 to 100 ℃. The pressurization (and heating) is preferably performed for 0.1 to 2 seconds.

Next, as shown in fig. 5 (b), a second circuit member 36 including a second circuit substrate 34 and a second circuit electrode 35 formed on a main surface 34a of the second circuit substrate 34 is prepared. Next, after the base material 25 of the adhesive tape 24A is peeled off from the adhesive film 1, the first circuit member 33 and the adhesive film 1 are placed on the second circuit member 36 so that the first circuit electrode 32 faces the second circuit electrode 35.

Specific examples of the second circuit member 36 include an LCD module. The second circuit electrode 35 may be formed of one or more selected from gold, silver, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, and Indium Tin Oxide (ITO). The second circuit electrodes 35 may be made of the same material or different materials.

Then, the whole is pressurized in the directions of arrows C and D while heating. The heating temperature in this case is not particularly limited as long as the

adhesive components

2a, 3a, and 4a of the adhesive film 1 can be cured, and is preferably 60 to 180 ℃, more preferably 70 to 170 ℃, and still more preferably 80 to 160 ℃. If the heating temperature is 60 ℃ or higher, an appropriate curing speed can be maintained, and if it is 180 ℃ or lower, an undesired side reaction can be suppressed. The heating time is preferably 0.1 to 180 seconds, more preferably 0.5 to 180 seconds, and further preferably 1 to 180 seconds.

The conditions for the connection are appropriately selected depending on the application of the obtained circuit connection body and the types of the adhesive film and the circuit member. When the

adhesive components

2a, 3a, and 4a of the adhesive film 1 are adhesive components that are cured by light, the adhesive film 1 may be appropriately irradiated with active light or energy rays at the time of connection. Examples of the active light include ultraviolet rays, visible light, and infrared rays. Examples of the energy ray include an electron ray, an X-ray, a γ ray, and a microwave.

In this way, the

adhesive components

2a, 3a, and 4a are cured to form the connection portions 38 between the cured products 37 containing the

adhesive components

2a, 3a, and 4a and the conductive particles 5, and the circuit connected body 39 as shown in fig. 5 (c) is obtained. That is, the circuit connecting body 39 includes the first circuit member 33, the second circuit member 36, and the connecting portion 38 provided between the first circuit member 33 and the second circuit member 36. In the circuit connecting body 39, the first circuit electrode 32 and the second circuit electrode 35 are electrically connected via the conductive particles 5. That is, since the conductive particles 5 are in direct contact with both the first and

second circuit electrodes

32 and 35, the connection resistance between the first and

second circuit electrodes

32 and 35 is sufficiently reduced, and good electrical connection between the first and

second circuit electrodes

32 and 35 can be achieved. On the other hand, since the cured product 37 has electrical insulation, insulation between the adjacent first circuit electrodes 32 and the second circuit electrodes 35 can be ensured. Therefore, in the circuit connecting body 39, the current flow between the first and

second circuit electrodes

32 and 35 becomes smooth, and the functions of the

circuit members

33 and 36 can be sufficiently exhibited.

In the above-described method for manufacturing the circuit-connected body 39, since the adhesive film 1 is temporarily connected to the first circuit member 33 such as an FPC board or a COF board, the amount of the adhesive film 1 used can be suppressed to the minimum as compared with the case where the adhesive film 1 is temporarily connected to the second circuit member 36 such as an LCD module, and the manufacturing cost can be reduced. In addition, in the method for manufacturing the circuit-connected body 39, since the adhesive film 1 in which the thickness of the first nonconductive adhesive layer 2 is smaller than the thickness of the conductive adhesive layer 3 is used, when the first and

second circuit members

33 and 36 are connected to each other, the conductive particles 5 are easily captured between the first and

second circuit electrodes

32 and 35, and good electrical connection can be achieved.

In the above embodiment, the adhesive tape 24A including the adhesive film 1 according to the first embodiment is used as the adhesive tape, but the adhesive tape 24B including the adhesive film 11 according to the second embodiment may be used as the adhesive tape.

Examples

The present invention will be described in further detail below with reference to examples, but the present invention is not limited to these examples.

(example 1)

[ Synthesis of urethane acrylate ]

400 parts by mass of polycaprolactone diol having a weight average molecular weight of 800, 131 parts by mass of 2-hydroxypropyl acrylate, 0.5 part by mass of dibutyltin dilaurate as a catalyst, and 1.0 part by mass of hydroquinone monomethyl ether as a polymerization inhibitor were heated to 50 ℃ while stirring and mixed. Then, 222 parts by mass of isophorone diisocyanate was added dropwise thereto, and the temperature was raised to 80 ℃ with stirring to perform a urethanization reaction. After the reaction rate of the isocyanate group was confirmed to be 99% or more, the reaction temperature was lowered to obtain a urethane acrylate.

[ preparation of polyester urethane resin ]

Two polyester urethane resins A, B were prepared by using terephthalic acid as a dicarboxylic acid, propylene glycol as a diol, and 4,4 '-diphenylmethane diisocyanate as an isocyanate, respectively, so that the molar ratio of terephthalic acid/propylene glycol/4, 4' -diphenylmethane diisocyanate was 1.0/1.3/0.25 or 1.0/2.0/0.25. Each polyester urethane resin was dissolved in methyl ethyl ketone so as to be 20 mass%. Each methyl ethyl ketone solution of the polyester urethane resin was applied to a PET film having a thickness of 80 μm, one surface of which was subjected to surface treatment, using a coating apparatus, and hot air-dried at 70 ℃ for 10 minutes, thereby obtaining a film having a thickness of 35 μm. For each film, the temperature dependence of the elastic modulus was measured at a tensile load of 5g and a frequency of 10Hz using a wide-area dynamic viscoelasticity measuring apparatus. The glass transition temperature of the polyester urethane resin thus obtained is polyester urethane resin a: 105 ℃, polyester urethane resin B: at 70 ℃.

[ production of first nonconductive adhesive layer ]

As the radical polymerizable material, 20 parts by mass of the urethane acrylate, 20 parts by mass of bis (acryloyloxyethyl) isocyanurate (product name: M-325, available from Toyo Synthesis Co., Ltd.), 10 parts by mass of dimethylol tricyclodecane diacrylate (product name: DCP-A, available from Kyodo chemical Co., Ltd.), and 1 part by mass of 2-methacryloyloxyethyl acid phosphate (product name: P-2M, available from Kyodo chemical Co., Ltd.) were used, and as the radical initiator, 3 parts by mass of benzoyl peroxide (product name: Nyper BMT-K, available from Nichio oil Co., Ltd.) was used. These components were mixed with 50 parts by mass of a 23 mass% solution obtained by dissolving polyester urethane resin B in a mixed solvent of toluene/methyl ethyl ketone (50/50), and the mixture was stirred to obtain a resin solution. This resin solution was applied to a PET film having a thickness of 50 μm and surface-treated on one surface thereof using a coating apparatus, and hot air drying was performed at 70 ℃ for 10 minutes, thereby obtaining a laminate PA (width 15cm, length 80m) of the PET film and a nonconductive adhesive layer a (first nonconductive adhesive layer) having a thickness of 2 μm.

[ production of conductive adhesive layer ]

As the radical polymerizable material, 25 parts by mass of the urethane acrylate, 15 parts by mass of bis (acryloyloxyethyl) isocyanurate (product name: M-325, manufactured by Toyo Synthesis Co., Ltd.) and 1 part by mass of 2-methacryloyloxyethyl acid phosphate (product name: P-2M, manufactured by Kyoeisha chemical Co., Ltd.) were used, and as the radical initiator, 3 parts by mass of benzoyl peroxide (product name: Nyper BMT-K40, manufactured by Nichio oil Co., Ltd.) was used. These components were mixed with 60 parts by mass of a 20 mass% methyl ethyl ketone solution of polyester urethane resin a, followed by stirring to obtain a binder resin solution. On the other hand, a nickel layer having a thickness of 0.1 μm was formed on the surface of the polystyrene particles, and a gold layer having a thickness of 0.04 μm was formed on the outside of the nickel layer, thereby obtaining conductive particles having an average particle diameter of 3 μm (20% compression modulus of elasticity (K value): 500 Kgf/mm)²). This conductive particle was dispersed in a binder resin solution by 3 vol%, and coated on a 50 μm thick PET film having one surface treated with a coating device, and hot air dried at 70 ℃ for 10 minutes to obtain a laminate PB (width 15cm, length 80m) of the PET film and a conductive adhesive layer B having a thickness of 3 μm.

[ production of second nonconductive adhesive layer ]

As the radical polymerizable material, 20 parts by mass of the urethane acrylate, 20 parts by mass of bis (acryloyloxyethyl) isocyanurate (product name: M-325, available from Toyo Synthesis Co., Ltd.), 10 parts by mass of dimethylol tricyclodecane diacrylate (product name: DCP-A, available from Kyodo chemical Co., Ltd.), and 1 part by mass of 2-methacryloyloxyethyl acid phosphate (product name: P-2M, available from Kyodo chemical Co., Ltd.) were used, and as the radical initiator, 3 parts by mass of benzoyl peroxide (product name: Nyper BMT-K, available from Nichio oil Co., Ltd.) was used. These components were mixed with 50 parts by mass of a 23 mass% solution obtained by dissolving polyester urethane resin B in a mixed solvent of toluene/methyl ethyl ketone (50/50), and the mixture was stirred to obtain a resin solution. This resin solution was applied to a 50 μm thick PET film having one surface treated by a coating apparatus, and hot air-dried at 70 ℃ for 10 minutes to obtain a laminate PC (width 15cm, length 70m) of the PET film and a non-conductive adhesive layer C (second non-conductive adhesive layer) having a thickness of 8 μm.

[ production of adhesive film ]

The obtained laminate PA and laminate PB were laminated so that the non-conductive adhesive layer A and the conductive adhesive layer B faced each other, using a laminator (product name: RISTON, model: HRL, manufactured by Dupont, roller pressure: spring load only, roller temperature: 40 ℃, speed: 50 cm/min). Subsequently, the PET film on the conductive adhesive layer B side was peeled off to obtain a laminate PAB (width 15cm, length 70m) in which the PET film, the non-conductive adhesive layer A, and the conductive adhesive layer B were laminated in this order.

Then, the obtained laminate PAB and laminate PC were laminated so that the conductive adhesive layer B and the non-conductive adhesive layer C faced each other, using a laminator (product name: RISTON, model: HRL, manufactured by Dupont, roller pressure: spring load only, roller temperature: 40 ℃, speed: 50 cm/min). Subsequently, the PET film on the non-conductive adhesive layer C side was peeled off to obtain a laminate PABC (width 15cm, length 60m) of a PET film (base material) and an adhesive film in which the non-conductive adhesive layer a, the conductive adhesive layer B, and the non-conductive adhesive layer C were laminated in this order.

The end faces of the obtained layered product PABC were observed with a Scanning Electron Microscope (SEM), and the length L of the conductive region, the length L1 of the first nonconductive region R1, and the length L2 of the second nonconductive region R2 were measured as follows.

First, in the laminate PABC, the length of a region (conductive region) between a first tangential plane, which is a plane in contact with the conductive particles and substantially parallel to the interface (line on SEM image, the same applies hereinafter) between the PET film and the non-conductive adhesive layer a, and a second tangential plane, which is a plane in contact with the conductive particles and substantially parallel to the surface of the laminate PABC on the non-conductive adhesive layer C side, and which is a plane at the shortest distance from the surface, was measured as L.

The length of a region (first non-conductive region) other than the conductive region extending in the thickness direction of the laminate PABC from the first tangential plane toward the surface of the laminate PABC on the non-conductive adhesive layer a side was measured as L1.

Further, the length of a region (second non-conductive region) other than the conductive region extending in the thickness direction of the laminate PABC from the second cut plane toward the non-conductive adhesive layer C side surface of the laminate PABC is measured as L2.

As a result, L3 μm, L1 2 μm, and L2 8 μm.

[ production of reels for adhesive films ]

The obtained laminate PABC was cut into a tape shape having a width of 1.0mm to prepare an adhesive tape, and the adhesive tape was wound around a plastic core (width 1.7mm) having an inner diameter of 40mm and an outer diameter of 48mm by 50m so that the adhesive film surface was on the inside to obtain a roll for an adhesive film.

(example 2)

In the production of the conductive adhesive layer, a nickel layer having a thickness of 0.2 μm was formed on the surface of polystyrene particles, and a gold layer having a thickness of 0.04 μm was formed on the outside of the nickel layer, to obtain conductive particles having an average particle diameter of 4 μm (20% modulus of elasticity in compression (K value): 410 Kgf/mm)²) A laminate of a base material and an adhesive film (thickness: 14 μm) was obtained in the same manner as in example 1, except that the thickness of the conductive adhesive layer was set to 4 μm. In the same manner as in example 1, L, L1 and L2 were measured, and as a result, L was 4 μm, L1 was 2 μm, and L2 was 8 μm. The laminate was cut into a tape having a width of 1.0mm to prepare an adhesive tape, and a roll for an adhesive film was obtained in the same manner as in example 1.

(example 3)

A laminate of a base material and an adhesive film (thickness 14.5 μm) was obtained in the same manner as in example 2, except that the thickness of the first nonconductive adhesive layer was set to 2.5 μm and the thickness of the second nonconductive adhesive layer was set to 8 μm. In the same manner as in example 1, L, L1 and L2 were measured, and as a result, L was 4 μm, L1 was 2.5 μm, and L2 was 8 μm. The laminate was cut into a tape having a width of 1.0mm to prepare an adhesive tape, and a roll for an adhesive film was obtained in the same manner as in example 1.

(example 4)

A laminate of a base material and an adhesive film (thickness 15 μm) was obtained in the same manner as in example 1, except that the thickness of the first nonconductive adhesive layer was set to 2 μm and the thickness of the second nonconductive adhesive layer was set to 10 μm. In the same manner as in example 1, L, L1 and L2 were measured, and as a result, L was 3 μm, L1 was 2 μm, and L2 was 10 μm. The laminate was cut into a tape having a width of 1.0mm to prepare an adhesive tape, and a roll for an adhesive film was obtained in the same manner as in example 1.

(example 5)

A laminate of a base material and an adhesive film (thickness 14.5 μm) was obtained in the same manner as in example 1, except that the thickness of the first nonconductive adhesive layer was set to 2.5 μm and the thickness of the second nonconductive adhesive layer was set to 10 μm. In the same manner as in example 1, L, L1 and L2 were measured, and as a result, L was 3 μm, L1 was 2.5 μm, and L2 was 10 μm. The laminate was cut into a tape having a width of 1.0mm to prepare an adhesive tape, and a roll for an adhesive film was obtained in the same manner as in example 1.

Comparative example 1

As the radical polymerizable material, 20 parts by mass of the urethane acrylate, 15 parts by mass of bis (acryloyloxyethyl) isocyanurate (product name: M-325, manufactured by Toyo Synthesis Co., Ltd.) and 1 part by mass of 2-methacryloyloxyethyl acid phosphate (product name: P-2M, manufactured by Kyoeisha chemical Co., Ltd.) were used, and as the radical initiator, 3 parts by mass of benzoyl peroxide (product name: Nyper BMT-K40, manufactured by Nichio oil Co., Ltd.) was used. These components were mixed with 60 parts by mass of a 20 mass% methyl ethyl ketone solution of polyester urethane resin a, followed by stirring to obtain a resin solution. On the other hand, a nickel layer having a thickness of 0.1 μm was formed on the surface of the polystyrene particles, and a gold layer having a thickness of 0.04 μm was formed on the outside of the nickel layer, thereby obtaining conductive particles having an average particle diameter of 3 μm (20% compression)Elastic modulus (K value): 500Kgf/mm²). This conductive particle was dispersed in a binder resin solution by 3 vol%, and coated on a 50 μm thick PET film having one surface treated with a coating device, and hot air dried at 70 ℃ for 10 minutes to obtain a laminate PB '(width 15cm, length 70m) of the PET film and a conductive adhesive layer B' having a thickness of 3 μm.

As the radical polymerizable material, 20 parts by mass of the urethane acrylate, 20 parts by mass of bis (acryloyloxyethyl) isocyanurate (product name: M-325, available from Toyo Synthesis Co., Ltd.), 10 parts by mass of dimethylol tricyclodecane diacrylate (product name: DCP-A, available from Kyodo chemical Co., Ltd.), and 1 part by mass of 2-methacryloyloxyethyl acid phosphate (product name: P-2M, available from Kyodo chemical Co., Ltd.) were used, and as the radical initiator, 3 parts by mass of benzoyl peroxide (product name: Nyper BMT-K, available from Nichio oil Co., Ltd.) was used. These components were mixed with 50 parts by mass of a 23 mass% solution obtained by dissolving polyester urethane resin B in a mixed solvent of toluene/methyl ethyl ketone (50/50), and the mixture was stirred to obtain a resin solution. This resin solution was applied to a 50 μm thick PET film having one surface treated by a coating apparatus, and hot air-dried at 70 ℃ for 10 minutes to obtain a laminate PC '(width 15cm, length 70m) of the PET film and a 12 μm thick nonconductive adhesive layer C'.

The obtained laminate PB 'and laminate PC' were laminated so that the conductive adhesive layer B 'and the non-conductive adhesive layer C' faced each other, using a laminator (product name: RISTON, model: HRL, manufactured by Dupont, roller pressure: spring load only, roller temperature: 40 ℃, speed: 50 cm/min). Subsequently, the PET film on the side of the non-conductive adhesive layer C ' was peeled off to obtain a laminate PB ' C ' (width 15cm, length 60m) of the PET film (base material) and the adhesive formed of the conductive adhesive layer B ' and the non-conductive adhesive layer C '. L and L2 were measured in the same manner as in example 1, and as a result, L was 3 μm and L2 was 12 μm. The obtained laminate was cut into a tape shape having a width of 1.0mm to prepare an adhesive tape, and the tape was wound around a plastic core (width 1.7mm) having an inner diameter of 40mm and an outer diameter of 48mm by 50m so that the adhesive film surface was on the inside to obtain a roll for an adhesive film.

Comparative example 2

In the production of the conductive adhesive layer, a nickel layer having a thickness of 0.2 μm was formed on the surface of polystyrene particles, and a gold layer having a thickness of 0.04 μm was formed on the outside of the nickel layer, to obtain conductive particles having an average particle diameter of 4 μm (20% modulus of elasticity in compression (K value): 410 Kgf/mm)²) A laminate of a base material and an adhesive film (thickness: 16 μm) was obtained in the same manner as in comparative example 1, except that the thickness of the conductive adhesive layer was set to 4 μm. L and L2 were measured in the same manner as in example 1, and as a result, L was 4 μm and L2 was 8 μm. The laminate was cut into a tape having a width of 1.0mm to prepare an adhesive tape, and a roll for an adhesive film was obtained in the same manner as in comparative example 1.

Comparative example 3

A laminate of a base material and an adhesive film (thickness: 13 μm) was obtained in the same manner as in example 1, except that the thickness of the first nonconductive adhesive layer was set to 4 μm and the thickness of the second nonconductive adhesive layer was set to 6 μm. In the same manner as in example 1, L, L1 and L2 were measured, and as a result, L was 3 μm, L1 was 4 μm, and L2 was 6 μm. The laminate was cut into a tape having a width of 1.0mm to prepare an adhesive tape, and a roll for an adhesive film was obtained in the same manner as in example 1.

Comparative example 4

A laminate of a base material and an adhesive film (thickness: 14 μm) was obtained in the same manner as in example 2, except that the thickness of the first nonconductive adhesive layer was set to 4 μm and the thickness of the second nonconductive adhesive layer was set to 6 μm. In the same manner as in example 1, L, L1 and L2 were measured, and as a result, L was 4 μm, L1 was 4 μm, and L2 was 6 μm. The laminate was cut into a tape having a width of 1.0mm to prepare an adhesive tape, and a roll for an adhesive film was obtained in the same manner as in example 1.

(reference example)

In comparative example 1, a laminate of a base material and an adhesive film (thickness 15 μm) was obtained in the same manner as in comparative example 1, except that after the laminate PB 'and the laminate PC' were laminated, the PET film on the conductive adhesive layer B 'side was peeled off instead of the PET film on the conductive adhesive layer C' side. L and L2 were measured in the same manner as in example 1, and as a result, L was 3 μm and L2 was 12 μm. The laminate was cut into a tape having a width of 1.0mm to prepare an adhesive tape, and a roll for an adhesive film was obtained in the same manner as in comparative example 1.

< evaluation of Presence or absence of adhesion >

The adhesive film was placed in a 30 ℃ thermostat (humidity: 40-60% RH) with a reel placed horizontally, and left to stand for 1 day (24 hours). Then, the adhesive tape was pulled out at a rate of 1 m/min to the terminal end using a tensile compression tester (product name: STA-1150, manufactured by Orientec corporation). The adhesive film was evaluated as "blocking" when it peeled off the PET film halfway, and as "no" when the adhesive tape could be pulled out without peeling off the adhesive film from the PET film. The evaluation results are shown in tables 1 and 2.

< manufacture of Circuit connecting body >

The adhesive film surface of each adhesive tape (width 1.0mm, length 3cm) obtained in examples and comparative examples was placed on an FPC board having 500 tin-plated copper circuits with a pitch of 40 μm and a thickness of 8 μm, and in this state, the PET film was peeled off after heating and pressing at 70 ℃ and 1MPa for 1 second, thereby temporarily connecting the adhesive film to the FPC board. Subsequently, an adhesive film and an FPC substrate were placed on an ITO coated glass substrate (15. omega. □) having a thickness of 1.1mm, and temporarily fixed at 50 ℃ under a pressure of 0.5MPa for 0.5 second. A glass substrate having an FPC board temporarily fixed thereto by an adhesive film was set in a main pressure bonding apparatus, and a silicone rubber having a thickness of 200 μm was used as a buffer material, and the mixture was heated and pressed at 170 ℃ and 3MPa for 5 seconds from the FPC board side by a heating tool (heat tool), and connected over the entire width of the adhesive film by 1.0mm to obtain a circuit connected body. In addition, only for the reference example, the adhesive film was temporarily attached to the ITO-coated glass substrate first, and then the FPC substrate was temporarily fixed to the adhesive film. Except for this, a circuit connected body was obtained under the same conditions as in the above-described examples and comparative examples.

< measurement of connection resistance >

With respect to each of the circuit-connected bodies thus produced, the resistance value between adjacent circuits of the FPC board including the connection portion was measured using a multimeter (device name: TR6845, manufactured by Advantest). The resistance between the adjacent circuits at 30 points was measured, and the resistance value was determined as the average value of these. The evaluation results are shown in tables 1 and 2.

< measurement of adhesive Strength >

For each of the circuit connected bodies produced, the FPC substrate was stretched perpendicularly to the main surface of the substrate at a peeling speed of 50 mm/min (90-degree peeling), and the adhesion was measured. The evaluation results are shown in tables 1 and 2.

[ Table 1]

[ Table 2]

As shown in table 1, in examples 1 to 5, no blocking occurred, and good connection resistance and adhesion were obtained.

As shown in table 2, blocking occurred in both comparative examples 1 and 2 (therefore, evaluation of connection resistance and adhesive strength was not performed). On the other hand, in the adhesive film (reference example) composed of two layers in general, in which the nonconductive adhesive layer was formed on the base material and the conductive adhesive layer was further formed on the nonconductive adhesive layer, blocking did not occur, and the evaluation results of the connection resistance and the adhesive strength were also good. In comparative examples 3 and 4, an increase in connection resistance was observed.

As described above, according to the present invention, for example, the adhesive can be attached to the FPC substrate side, the occurrence of blocking can be suppressed, and excellent connection reliability can be obtained when the adhesive is used for manufacturing a circuit connection body.

Description of the symbols

1. 11, 26 … adhesive film, 2 … first non-conductive adhesive layer, 3 … conductive adhesive layer, 4 … second non-conductive adhesive layer, 5 … conductive particles, 21 … reel for adhesive film, 22 … core, 24A, 24B … adhesive tape, 25 … base material, R … conductive region, R1 … first non-conductive region, R2 … second non-conductive region.

Claims

1. An adhesive tape comprising a tape-shaped base material and an adhesive film, wherein the adhesive film is formed by sequentially laminating a first nonconductive adhesive layer, a conductive adhesive layer containing conductive particles, and a second nonconductive adhesive layer,

the thickness T1 of the first non-conductive adhesive layer and the thickness T of the conductive adhesive layer satisfy the following formula (1),

T1＜T…(1)，

the thickness T2 of the T1 and the second non-conductive adhesive layer satisfies T1 ≤ 0.5 × T2,

the T is 1.5-4 μm,

the T1 is 0.5-2.5 μm,

the T2 is 7-10 μm.

2. The adhesive tape according to claim 1, wherein the T1 and the conductive particles have an average particle diameter r satisfying the following formula (2),

T1≤0.8×r…(2)。

3. an adhesive tape comprising a tape-shaped base material and an adhesive film,

the adhesive film is an adhesive film containing conductive particles, and includes, in order in the thickness direction of the adhesive film, a first nonconductive region where the conductive particles are absent, a conductive region where the conductive particles are present, and a second nonconductive region where the conductive particles are absent,

a length L1 of the first non-conductive region in the thickness direction of the adhesive film and a length L of the conductive region in the thickness direction of the adhesive film satisfy the following formula (4),

L1＜L…(4)，

the length L2 of the L1 and the second non-conductive area in the thickness direction of the adhesive film satisfies L1 ≤ 0.5 × L2,

the L is 1.5-4 μm,

the L1 is 0.5-2.5 μm,

the L2 is 7-10 μm.

4. The adhesive tape according to claim 3, wherein the average particle diameter r of L1 and the conductive particles satisfies the following formula (5),

L1≤0.8×r…(5)。

5. a reel for an adhesive film, comprising:

the adhesive tape of any one of claims 1 to 4, and

a winding core around which the adhesive tape is wound.

6. A method for producing the adhesive tape according to any one of claims 1 to 4, comprising the steps of:

an adhesive film is obtained by laminating a first nonconductive adhesive layer, a conductive adhesive layer containing conductive particles, and a second nonconductive adhesive layer in this order on one surface of a strip-shaped base material.