JP2012079927A - Solderable conductive structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reliable solderable conductive structure, especially an EMC gasket which can be mounted on a printed circuit board (PCB).SOLUTION: The solderable conductive structure has a structure where a solderable layer (2) consisting of a pressure-sensitive adhesive resin (R) heavily blended with conductive powder (M) is provided at least on the bottom side lower surface of the outer peripheral surface of a conductive and elastic body (1). The body (1) is constituted of an electrical conductive portion (1A) between the bottom side lower surface and the top side upper surface thereof. The solderable layer (2) consists of a layer of the pressure-sensitive adhesive resin (R) heavily blended with conductive powder (M).

Description

  The present invention relates to a conductive structure (particularly an EMC gasket) capable of reliable soldering.

[Mounting of EMC gasket to PCB]
-1-
Various components are mounted on a printed circuit board (PCB).
EMI gasket (electromagnetic interference gaske)
The conductive gaskets t) and the electrical short-circuit terminals for ground reinforcement and grounding are also important parts to be mounted on the PCB, and are fixedly arranged at predetermined positions on the PCB. These conductive gaskets and electrical short-circuit terminals are both used as EMC countermeasure parts, and are generally collectively referred to as “EMC gaskets”. In the present invention, the technical term “EMC gaskets” It is used to mean “conductive gasket, electrical short-circuit terminal, or similar parts”. EMC is “electro magnetic compa
It is an abbreviation for “tibility” and refers to the ability to function as a device without being electromagnetically affected by other devices and without electromagnetically affecting other devices.
-2-
When the EMC gasket is a conductive gasket, fixing on the PCB may be performed by using a metal layer that can be soldered on the outer periphery of a core material having elasticity, or by using conductive material as described in Patent Document 1 described later. Using a gasket assembly provided with a solderable support layer such as a metal layer on the bottom side of the gasket, and placing the gasket or gasket assembly on the cream solder provided in advance on the PCB; This is accomplished by reflowing the cream solder.

[Patent Document 1]
-1-
JP-T-2002-510873 (Patent Document 1) uses “surface mounting EMI gasket and method of mounting EMI gasket on installation portion” as the title of the invention, and corresponds to WO99 / 51074, which is an international publication. . The application of Patent Document 1 is Japanese Patent No. 4249391 (the name of the invention is “surface mounting EMI gasket mounting method”).
It is patented as. This Patent Document 1 seems to be a basic document related to a surface mount EMI gasket.

-2-
Claim 1 of Patent Document 1 is as follows. Reference numerals 20, 22, 24, and 26 correspond to FIG. 1 and FIG. Of the other symbols in FIG. 1 or FIG. 1A of Patent Document 1, 28 is a solder layer, 30 is a ground trace, and 32 is a printed circuit board (PC).
B).
(Claim 1 of Patent Document 1)
・ An electrically conductive gasket material 22 and
・ A solderable, electrically conductive support layer
er) 24,
Means for fixing the conductive gasket material 22 to the solderable conductive support layer 24
(means for affixing the electrically conductive gasket material to the solderabl
e, electrically conductive support layer) 26 Electromagnetic interference (EMI) for SMT / a surface mount technology
Gasket assembly 20.

-3-
The EMI gasket assembly including the conductive gasket material 22 disclosed in Patent Document 1
The typical layer structure of “20” is “conductive gasket material” as shown in paragraph 0019 and FIG. 1A.
22 / adhesive 26 / conductive support layer 24 ”, and the“ conductive support layer 24 ”side is soldered by reflow of the solder layer 28. Here, the “conductive support layer 24” is typically the paragraph 0022.
In this way, it is composed of a solderable metal or a plastic plated with a solderable metal. In paragraph 0021, an electrical path between “conductive gasket material 22” and “conductive support layer 24” in “conductive gasket material 22 / adhesive 26 / conductive support layer 24” is secured. Therefore, there is a description that a conductive pressure-sensitive acrylic adhesive (or a thermosetting or thermoplastic adhesive) can be used as the “adhesive 26”.

-4-
In Patent Document 1, a screen-printable conductive adhesive is used, and “EMI Gasket” is used.
Twenty-two conductive support layers 24 (or EMI gaskets 22 themselves) are also shown to be bonded directly to the PCB mounting (paragraph 0014). At this time, the need for solder is completely eliminated.

-5-
In Patent Document 1, an “EMI gasket 22” is used without using a “conductive support layer 24” that can be soldered.
A method for directly soldering to the solder layer 28 is also shown (paragraph 0015).

-6
Further, in Patent Document 1, regardless of whether the conductive support layer 24 is used or not, the “EMI gasket or gasket assembly” is “via an adhesive” without using the solder layer 28.
A method for placement on a conductive surface is also shown (paragraph 0016).

[Patent Document 2]
In JP-A-2001-144399 (Patent Document 2), an inter-substrate connecting member 1 in which a core 2 made of a rigid conductor is covered with an elastic body 3 and the periphery of the elastic body 3 is covered with a conductive material 4. It is shown. According to the paragraph 0017 and FIGS. 1 and 2, “The inter-substrate connecting member 1 is an elastic material having heat resistance on the outer periphery of the columnar core body 2 made of a rigid conductor such as copper, for example,
It is covered with an elastic body 3 made of polyimide or the like, and the entire portion made up of the core body 2 and the elastic body 3 is covered with a conductive material 4 having conductivity such as copper. "
[0021] "A solder paste 9A is applied by printing on a connection land (electrode) 8A formed on the upper surface of the electronic circuit board 6A, and then the inter-substrate connection member 1 is mounted on the connection land 8A; There is a description of “mounting these by reflow heating”.

[Patent Document 3]
Japanese Patent Application Laid-Open No. 2001-267715 (Patent Document 3) discloses an electronic circuit device assembled by stacking a plurality of circuit boards on which electronic components are mounted. The circuit boards are stacked on each other, and the plurality of circuit boards are electrically connected to each other through the elastic body (claim 1). In this Patent Document 3, the conductive elastic body 10 is soldered by reflow of a solder paste 17 provided on a connection land 16 of one circuit board 15,
There is a description of pressure bonding to a connection land 24 provided on the other circuit board 23 (paragraphs 0008, 0).
013-0019, FIG. 2).

[Patent Document 4]
The invention of claim 1 of JP-A-2002-245850 (Patent Document 4) is “a conductive paste containing conductive powder and a binder at a specific blending ratio, and the glass transition point (Tg) of the cured conductive paste is “The conductive paste is 40 to 180 ° C.”. What is specifically shown as the binder is an epoxy resin composition (in particular, an epoxy resin composition containing a flexibility imparting agent) (Claims 2 and 3), and specifically shown as conductive powder. The thing is copper powder or copper alloy powder (Claims 4 and 5). According to the embodiment, the conductive paste is applied to the surface of the copper-clad laminate from which the copper foil has been removed by etching and subjected to heat treatment to obtain a conductor, and the surface of the conductor is made smooth and mirrored. Then, after applying solder flux to the smooth and mirrored surface, it is immersed in a solder bath and then pulled up and cooled to room temperature, thereby conducting the operation of soldering to the surface of the conductor. A test is performed to confirm that the body surface is soldered (paragraphs 0037 to 0038). It turns out that the electrically conductive paste of the cited reference 4 is excellent in solderability (paragraph 0061). The conductive paste of Cited Document 4 is used as an electronic component, circuit wiring material, electrode material, and conductive bonding material, and can be directly soldered (paragraph 0001).

[Patent Document 5]
JP-A-60-11574 (Patent Document 5) shows an adhesive transfer tape 10 in which an adhesive layer 16 containing conductive powder is lightly adhered on a low adhesion support web 12. It is said that a heat-activatable adhesive (thermosetting, hot melt or heat-tackifying adhesive) is suitable as the adhesive. There is also an explanation of the glass transition point Tg. In the case of an acrylic polymer, when it has an appropriate average Tg, it is non-poorly tacky at room temperature, but it becomes sticky when heated. There is also reference to pressure sensitive adhesives, adhesives that are non-tacky at room temperature will keep the conductive particles in place well when the tape is applied to make electrical connections and will be exposed briefly to the soldering temperature. It will be safer and more resistant to. It is also described that approximately the same results can be achieved by cross-linking low Tg polymers after electrical coupling is performed.

[Patent Document 6]
In JP-A-5-196812 (Patent Document 6), a polarized light having an adhesive layer made of an acrylic resin and acrylic rubber on at least one of protective layers of a polarizing plate in which both surfaces of a polarizing film are covered with protective layers. A board is shown. In the examples, the acrylic resin is “n”.
A glass transition temperature Tg consisting of “a copolymer of butyl acrylate (/ ethyl acrylate) / acrylic acid (/ 2-hydroxyethyl methacrylic acid)” of −50 ° C. to −52 ° C. is used. A glass transition temperature Tg of “-butyl acrylate / acrylonitrile / 2-hydroxyethyl acrylate copolymer” having a glass transition temperature Tg of about −42 ° C. is used. And in addition to these acrylic resins and acrylic rubber, as a crosslinking agent, an adhesive solution containing 3 mol of tolylene diisocyanate and 1 mol of trimethylolpropane, cyclohexane diisocyanate or isophorone diisocyanate is used, The pressure-sensitive adhesive layer is formed.

Special table 2002-510873 JP 2001-144399 A JP 2001-267715 A JP2002-245850 JP 60-11574 Japanese Patent Laid-Open No. 5-196812

(Regarding Patent Document 1)
A typical layer configuration of the “assembly 20 including a conductive gasket” disclosed in Patent Document 1 is as follows:
“Conductive gasket material 22 / adhesive 26 / conductive support layer 24” (“conductive support layer 24” is made of solderable metal or plastic plated with solderable metal) In this layer configuration, it is considered that the “conductive support layer 24” side is firmly soldered by the reflow of the solder layer 28 and becomes reliable. However,
Since the assembly 20 having the “conductive support layer 24” is structurally complicated, the intended use may not be possible depending on the shape and size of the conductive gasket material 22, and the manufacturing cost may be reduced. It is inevitable that it will be disadvantageous.

In addition, the aspects other than the above described in Patent Document 1 are based on the mounted conductive gasket material 22.
The question remains about the fixed point to the PCB installation part, and there is anxiety about the reliability.

Patent Document 1 seems to be a basic document related to a surface mount EMI gasket, but the unique structure as in the present invention is not conceived.

(Regarding Patent Document 2)
In the inter-substrate connecting member 1 of Patent Document 2, since the columnar core 2 is intended to accurately separate the upper and lower substrates, there is no elasticity in the vertical direction of the column (rather than the column body). The elasticity of the elastic member 3 such as polyimide of the connecting member 1 is not to be elastic in the vertical direction)
As shown in FIG. 8, the upper edge of the outer periphery of the cylindrical connecting member 1 is fitted with the fitting recess 13 of the installation land 12B.
Since it is only elastic enough to allow only a slight deformation that can be pushed into B, it cannot be used for anything other than “separation (ensure space) and conduction” between the upper and lower substrates.

(Regarding Patent Document 3)
In Patent Document 3, the separation between the upper and lower substrates 15 and 23 is maintained by “an elastic body 10 whose outer surface is electrically conductive by the conductive layer 11 (a core having rigidity at the center”). 38 may be arranged) ”, and is made to bear the“ substrate connecting elastic body ”. Here, a representative example of the conductive layer 11 is Cu, a representative example of the elastic body 10 is polyimide, and a representative example of the core 38 is Cu.
The Cu of 11 and the Cu of the core 38 are not elastic bodies, and the polyimide called the elastic body 10 in the cited document 3 is an engineer plastic having a small elongation at break and an extremely high glass transition point. It is a resin opposite to rubber and rubber (having a very high elongation at break and a very low glass transition point). In Patent Document 3, the “substrate connecting elastic body” is interposed between the substrates 15 and 23 in a crushed state (Claim 2), but if such a crushed state continues, plasticity is obtained. Since it is in a deformed state and almost no restoring force due to elastic deformation can be expected, the clip 28 (FIG. 3), the bolt 29 and the nut 30 (FIG. 4), and the presser 34 (defining the gap between the upper and lower substrates 15, 23 FIG. 5) is unavoidable to be in a loose state. In the cited document 3, since the plastic deformation of the “substrate connecting elastic body” is unavoidable, it is reliable in the long term in terms of mechanical connection and electrical connection of the electronic circuit device as the object. Seems to lack.

[Patent Document 4]
When the conductive paste containing conductive powder and binder shown in Patent Document 4 is applied to an electronic component to form a coating film for an electric circuit or an electrode, it is soldered directly to the coating film. Therefore, it seems to be useful as one of conductive materials. Here, a typical binder is composed of an epoxy resin having two or more epoxy groups in the molecule, a curing agent thereof, and a flexibility imparting agent having one epoxy group in the molecule. The conductive paste of Document 4 is considered to belong to the category of conventionally known thermosetting conductive paints or thermosetting conductive adhesives. In Patent Document 4, the paragraphs 0037 to 0038 are used.
Thus, a conductive paste is applied to the surface of the copper clad laminate from which the copper foil has been removed by etching to obtain a conductor, and the surface of the obtained conductor is polished with water-resistant abrasive paper to make it smooth and mirror-finished After the solder flux is applied to the solder, it is immersed in a solder bath, reflowed, then allowed to cool at room temperature, and then the adhesion is tested. It is understood that this conductor is hard because it is made of epoxy resin as a binder, and therefore can be polished, and conductive powder is exposed on the polished surface, so that soldering is possible.

[Patent Document 5]
In Patent Document 5, the behavior of the adhesive of the adhesive layer 16 containing conductive powder at room temperature and during heating is pursued. However, the invention of this document is an adhesive containing conductive powder on the low adhesion support web 12. The adhesive layer 16 is applied to the adhesive transfer tape 10 to which the agent layer 16 is lightly adhered, and is completely different in structure and usage from the present invention.

(Regarding Patent Document 6)
Patent Document 6 describes a pressure-sensitive adhesive layer composed of an acrylic resin and acrylic rubber. The invention of this document relates to a polarizing plate having a pressure-sensitive adhesive layer, and its purpose and use are also described in the present invention. Is completely different from the above and has nothing to do with conductivity or solderability.

[Object of invention]
Under such a background, the present invention provides a conductive structure (in particular, an EM that can be mounted on a printed circuit board (PCB)) that can be soldered reliably even though the outer peripheral surface is not a metal layer.
C gasket).

The solderable conductive structure of the present invention is:
-Having a structure in which a solderable layer (2) is provided on the bottom surface of at least the bottom side of the outer peripheral surface of the electrically conductive and elastic main body (1);
The main body (1) is composed of a conductive portion (1A) that is electrically connected between the bottom side bottom surface and the top side top surface; and
The solderable layer (2) is composed of a pressure-sensitive adhesive resin (R) layer that is highly blended with conductive powder (M),
It is characterized by.

(Technical thought and operational effects of the present invention)
-0-
Explaining the present invention with a typical example, in order to obtain the conductive structure of the present invention, on the lower surface at least on the bottom side of the outer peripheral surface of the conductive and elastic main body (1), A solderable layer (2) made of a pressure-sensitive adhesive resin (R) containing a high amount of conductive powder (M) is applied to form a coating film. The coated film typically becomes the solderable layer (2) through the following state. FIG. 1 shows a main body (1) for obtaining a conductive structure of the present invention.
FIG. 3 is a cross-sectional view schematically showing the relationship between a solderable layer (2) and solder.

-1-
FIG. 1A shows an example in which the entire body portion (1) is composed of a conductive portion (1A).
The conductive portion (1A) is composed of a composition in which conductive powder (M ′) is blended with a resin or rubber component (R ′).

-2-
1. Composition for forming a solderable layer (2) made of a pressure-sensitive adhesive resin (R) in which conductive powder (M) is highly blended on the bottom side of the main body (1) in FIG. The coating film (C1) immediately after coating is in a liquid phase that contains a solvent and wets the conductive part (1A) of the main body (1). Yes (see FIG. 1B).
2. In the drying process, the solvent is volatilized from this coating film (C1), and finally the dry coating film (C1
2) (see (C) in FIG. 1). This dry coating film (C2) is the solderable layer (2) in the present invention. This dry coating (C2) (ie solderable layer (2)) is a pressure sensitive adhesive resin.
It adheres firmly to the surface of the main body (1) by the adhesive force of (R). It can be easily confirmed that the dry coating film (C2) is strongly bonded to the surface of the main body (1).

-3-
1. In the dried coating film (C2), the particles of the conductive powder (M) are in close packing or close to each other, so the particles are in contact with each other. The pressure-sensitive adhesive resin (R) is present. In this state, the adhesive force between the particles of the conductive powder (M) by the pressure-sensitive adhesive resin (R) is strong. In addition, the conductive powder (M) particles are in contact with each other in the entire area of the dry coating (C2) (both inside and on both surfaces), and the dry coating (C2) is electrically charged in all directions including the layer thickness direction. However, such a state can be easily confirmed.
2. And the conductive powder (M) in the dry coating film (C2) also contacts the conductive powder (M ′) of the conductive part (1A) of the main body part (1) at the interface with the main body part (1), Electrical conduction also occurs between the dried coating (C2) and the main body (1). This fact can also be easily confirmed.

-4-
On the other hand, the pressure-sensitive adhesive resin (R) is highly blended due to the fact that the “surface on the free surface side” of the dry coating (C2) is substantially tack-free. It is understood that the conductive powder (M) mainly exists in the contact portion between the particles of the conductive powder (M) and the void portion between the particles, and plays a role of a binder (binder) that bonds the particles to each other. In addition, it can be easily confirmed that the adhesive force between the particles of the conductive powder (M) on the “free surface side” of the dry coating film (C2) is as strong as the inner side. By the way, in the case of a general conductive pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer containing conductive powder is formed on a sheet such as a tape or film, the free surface side of the pressure-sensitive adhesive layer containing the conductive powder is used. The surface naturally has a tack (otherwise, it cannot be attached to the object), and the film structure and properties are essentially different from the above-mentioned dry coating film (C2) in the present invention.

-5-
1. Next, as shown in FIG. 1D, the structure of FIG. 1C is applied to the cream solder (S) on the printed circuit board (PCB) (having some adhesiveness). Mount in such a posture that the free surface side of the dry coating (C2) (that is, the solderable layer (2)) faces the cream solder (S).
2. Next, as shown in FIG. 1E, the cream solder (S) is reflowed and then cooled, and the structure is soldered.

-6
1. At this time, the conductive powder (M) particles are densely present on the free surface side of the dry coating film (C2) (solderable layer (2)) of the structure, and the reflow of cream solder (S) Since the peak temperature in the temperature profile of this time is about 260 ° C, for example, the "viscoelasticity" of the pressure-sensitive adhesive resin (R) in the solderable layer (2) is easy to flow As a result, the force of the pressure-sensitive adhesive resin (R) near the free surface easily moves toward the inner side of the solderable layer (2), and the conductive powder (M) particles Pressure-sensitive adhesive resin that exists between surfaces and particles
(R) film is thinned or torn. The possible mechanism for such a phenomenon is as follows.
-Pressure-sensitive adhesive resin is a viscoelastic body that has a glass transition point or higher and exhibits moderate viscoelasticity at a normal use temperature of about 5 to 80 ° C., but becomes a fluid that flows under higher temperature conditions. . For the temperature dependence of pressure-sensitive adhesives (pressure-sensitive adhesives), see “Adhesion Handbook (Third Edition)”.
, “K BOOKS SERIES 164 Adhesive to learn from the beginning”, “Polymer New Material One Point-18 High-functional Adhesive / Adhesive”, “New Industrial Science Series Adhesion / Adhesive Science and Application” There is an explanation.
・ In the dry coating film (C2), there is a very small gap between solvent volatiles, and the viscosity of the coating film appears strongly at high temperatures, so that the fluidized pressure-sensitive adhesive resin (R) becomes capillary. It moves to fill the gap according to the phenomenon.
2. Therefore, on the solderable layer (2), particularly on the free surface side, the conductive powder (M) particles (metal 1) in the solderable layer (2) and reflowed cream solder (metal 2) It is understood that a situation in which direct contact and fusion between metals are likely to be achieved is achieved, and reliable soldering is achieved.

−7−
As described above, in the present invention, the “conductive powder (M) constituting the solderable layer (2) described above”
The potential of the pressure-sensitive adhesive resin (R) with a high content of is exhibited under special environmental conditions such as a temperature profile during reflow of the cream solder (S).

-8-
In addition, in the present invention, since the pressure-sensitive adhesive resin (R) is used as the resin (binder resin) corresponding to the binder of the solderable layer (2), various temperature conditions mainly at room temperature are used. The flexibility necessary for the solderable layer (2) can be maintained even below. Therefore, it is possible to follow elastic deformation of the main body (1) having conductivity and elasticity, which is advantageous in terms of durability.

-9-
In a preferred embodiment of the present invention, as the solderable layer (2) made of the pressure-sensitive adhesive resin (R) in which the conductive powder (M) is highly blended, an acrylic polymer or Since the pressure-sensitive adhesive resin (r) made of an acrylic rubber polymer is used, the pressure-sensitive adhesive resin (r
) Is fully utilized. In particular, in claim 6, the pressure-sensitive adhesive resin (r) has a functional group and has a glass transition point of −20 ° C. or lower, and an acrylic polymer or acrylic rubber-based polymer. Therefore, the above-described effects of the present invention are exhibited to the maximum.

  Hereinafter, the present invention will be described in detail.

[Main unit (1)]
The main body portion (1) having conductivity and elasticity is assumed to have elasticity. Having conductivity and elasticity can be said to be particularly suitable for the use of EMC gaskets.

The main body portion (1) needs to be configured as a conductive portion (1A) in which electrical conduction is established between the bottom-side lower surface and the top-side upper surface. Here, the conductive portion (1A) is composed of a composition in which conductive powder (M ′) is blended with a component (R ′) made of resin or rubber.

Examples of the component (R ′) made of resin or rubber include various silicone rubbers (millable silicone rubber, liquid silicone rubber, EPDM-modified silicone rubber, etc.) and various fluorine rubbers (vinylidene fluoride fluororubber, PTFE-). Propylene-based fluororubber, PFA-based fluororubber, fluorophosphazene-based fluororubber, etc.), EPDM (ethylene-propylene-diene copolymer rubber), and the like are representative examples of suitable materials for the main body (1). Ethylene-propylene copolymer rubber, ethylene-acrylic rubber, butyl rubber and the like can also be used.

Examples of the conductive powder (M ′) include gold powder, silver powder, copper powder, silver-coated copper powder, silver-coated aluminum powder, silver-coated nickel powder, nickel powder, aluminum powder, silver-coated glass beads, tin oxide, and tin oxide-coated oxide. Examples include titanium, graphite, nickel graphite, conductive carbon black, and carbon fiber. Silver powder, silver-coated copper powder, or a mixture of both is a representative example of a preferable conductive powder (M ′).

As described above, the main body portion (1) needs to be configured as the conductive portion (1A) in which the bottom surface on the bottom side and the top surface on the top side are electrically connected. Therefore, as long as it has such a configuration, the entire body portion (1) may be composed of a conductive portion (1A), and a portion of the body portion (1) is composed of a conductive portion (1A) and a body portion ( The other part of 1) may be composed of a non-conductive part (1B). The main body (1) may have a cavity (h) or may not have a cavity (h). (
A) to (J) are cross-sectional views showing examples of the shape or structure of the main body (1). As shown in FIG. 3I, the outer peripheral side may be the conductive portion (1A) and the inner peripheral side may be the conductive portion (1A).

The main body (1) is usually manufactured in the form of a long object or sheet, and is often cut into a predetermined size (including punching) into a chip shape. There is no limitation on the size of the chip, but the main usage of the solderable conductive structure of the present invention is printed circuit board (PC
B) For example, in the case of the shape and structure shown in FIGS. 3A to 3J above, the height is about 0.5 mm to 30 mm, and the width is about 0.5 mm. It is often about 30 mm (the length varies from short to long). However, the height and width may be made smaller or larger.

When the main body (1) is manufactured in the form of a long rod-like or small-diameter pipe, an extrusion method is often employed from the viewpoint of productivity. When the main body (1) is produced in the form of a wide sheet, it can be formed by a method of casting on an appropriate support surface or sheet in addition to the extrusion method.

When the extrusion molding method is employed, a so-called “one-color extrusion molding method” or “two-color extrusion molding method” is employed (an extrusion molding method of three or more colors is not excluded). In addition, "2" that extrudes two colors at the same time
Instead of the “color extrusion molding method”, a method in which a long molded body prepared in advance is used as a core and a molded body serving as a sheath around the core is extrusion coated is also employed.

When the entire body part (1) is composed of the conductive part (1A), the molding apparatus becomes simple and the control during molding becomes easy, but the expensive conductive powder used for forming the body part (1) ( Since the amount of M ′) used increases, it is disadvantageous in terms of material costs. On the other hand, the main body (1) is composed of a conductive part (1A) and a non-conductive part (1B).
Since the volume ratio of the conductive part (1A) can be significantly reduced, the amount of conductive powder (M ') used is small, which is advantageous in terms of material cost, but molding There is a disadvantage that the apparatus becomes complicated and the control during molding becomes complicated. Comparing both of them, the latter (the main body part (1) is composed of a conductive part (1A) and a non-conductive part (1B)) is often more advantageous, but the main part (1) When the height or width of the plate is extremely small, the former (the main body (1) is composed only of the conductive portion (1A)) may be used.

When the main body (1) is composed of a conductive part (1A) and a non-conductive part (1B), in order to further reduce the amount of conductive powder (M ') used, for example, as shown in (J) of FIG. In addition, the conductive part (1A) may be formed in an I shape in cross-sectional view, but the structure of the discharge port for forming the core of the extruder during molding by the two-color extrusion molding method is complicated, and the control during molding is also complicated. It becomes.

[Solderable layer (2)]
A solderable layer (2) described below is provided on the lower surface of at least the bottom side of the conductive and elastic main body (1). This solderable layer (2) is made of a pressure-sensitive adhesive resin (R) in which a conductive powder (M) is highly blended.

(Pressure-sensitive adhesive resin (R))
-1-
Here, as the pressure-sensitive adhesive resin (R), various resins having pressure-sensitive adhesiveness are used, but particularly preferred for the purpose of the present invention are “acrylic polymer” or “acrylic rubber-based resin”. A pressure-sensitive adhesive resin (r) comprising a polymer. And such a pressure sensitive adhesive resin (r
Among these, a particularly preferable one has a functional group and has a glass transition point (Tg) of −20 ° C. or lower (
In particular, it is -25 ° C or lower, and further -30 ° C or lower).

-2-
Among the above, “acrylic polymer” has a copolymer composition that can be used as a pressure-sensitive adhesive, that is, “main monomer that provides adhesion / comonomer that provides cohesiveness / tackiness, and crosslinking point” A copolymer composed of a “functional group-containing monomer” is used. Many pressure-sensitive adhesives comprising such a copolymer are commercially available from many manufacturers.

-3-
Here, as a main monomer which gives adhesiveness, the glass transition point of the homopolymer is -3.
Examples thereof include acrylic monomers having a temperature of about 0 ° C. or lower (particularly −40 ° C. or lower, especially −50 ° C. or lower). In the case of an n- (meth) alkyl group, an acrylic monomer having an alkyl group with about 4 to 10 carbon atoms (n-butyl acrylate, 2-ethylhexyl acrylate, n-
Octyl acrylate, isononyl acrylate, etc.) and methacrylic monomers having about 10 to 12 carbon atoms. For example, the glass transition points of n-butyl acrylate, 2-ethylhexyl acrylate, n-decyl acrylate, and n-dodecyl acrylate homopolymers are −54 ° C., −62 ° C., −45 ° C., − 65 ° C.
The glass transition points of the homopolymers of n-decyl methacrylate and n-dodecyl methacrylate are −45 ° C. and −65 ° C. in this order.

-4-
Examples of comonomers that give cohesion include acrylic monomers (such as methyl methacrylate), vinyl esters (such as vinyl acetate), styrene monomers (such as styrene and α-methylstyrene), and nitrile monomers (acrylonitrile, methacrylonitrile). Etc.) and other monomers that can be copolymerized with the above main monomers. For reference, the glass transition points of homopolymers of ethyl acrylate, methyl methacrylate, vinyl acetate, styrene, and acrylonitrile are −24 ° C., + 105 ° C., + 30 ° C., +1 in this order.
It is 00 degreeC and + 104-130 degreeC.

-5-
Examples of the functional group-containing monomer that gives tackiness and serves as a crosslinking point (that is, a polar group or functional group-containing monomer such as a hydroxyl group, an epoxy group, an amide group, or an amino group) include 2
Hydroxyl group-containing acrylic monomers such as hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate; carboxyl group-containing acrylic monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic anhydride; glycidyl acrylate, glycidyl methacrylate, etc. Epoxy group-containing acrylic monomers; acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, and the like. For reference, the glass transition points of homopolymers of acrylic acid, methacrylic acid, and acrylamide are + 106 ° C., + 228 ° C., and + 109 ° C. in this order.

-6
The glass transition point Tg of the copolymer is “New polymer material One-Point-18“ High-performance adhesives / adhesives ”, published by Kyoritsu Publishing Co., Ltd. 105-1
"See page 06)" and "" Adhesion / Adhesion Chemistry and Applications ", published by Dai Nippon Book Co., Ltd., pages 115-116 of the first edition issued on February 5, 1998. (W is the weight fraction of each monomer).
1 / Tg = W1 / Tg1 + W2 / Tg2 + ... + Wn / Tgn

−7−
Next, among the above-mentioned “acrylic rubber-based polymer”, the same as the above-mentioned “acrylic polymer” “main monomer that provides adhesion / comonomer that provides cohesiveness / adhesiveness and crosslinking point” Among the copolymers consisting of “functional group-containing monomers”, there are polymers that give rubber elasticity, and those using acrylonitrile or methacrylonitrile as comonomers that give cohesiveness are particularly important. The acrylic rubber polymer has a glass transition point of -3.
Those having a temperature of 0 ° C. or lower (particularly −35 ° C. or lower) are preferable. Examples of commercially available products include “Toa Akron” manufactured by Toa Paint Co., Ltd., “Taisan Rubber” manufactured by Teikoku Sangyo Co., Ltd., and “Aron Rubber” manufactured by Toa Synthetic Chemical Industry Co., Ltd.

-8-
It is particularly preferable that the pressure-sensitive adhesive resin (r) composed of the above “acrylic polymer” or “acrylic rubber polymer” contains a crosslinking agent. This is because the viscoelasticity suitable for achieving the object of the present invention can be obtained by blending the crosslinking agent (c).

-9-
Here, as the cross-linking agent, one corresponding to the functional group-containing monomer component incorporated in the polymer is selected and used. For example, when the functional group of the functional group-containing monomer component is “hydroxyl group”, melamine resin, urea resin, polyisocyanate, epoxy resin, metal chelate, etc. are used, and the functional group is “carboxyl group”. Melamine resin, urea resin, polyisocyanate, epoxy resin, metal oxide, metal metal peroxide, metal hydroxide, metal chelate, etc. are used, and the functional group is "epoxy group (glycidyl group)" In some cases, carboxyl group-containing polymers, acid anhydrides, polyamines, etc. are used. When the functional group is “N-methylolamide group”, melamine resin, urea resin, polyisocyanate, carboxyl group-containing polymer, epoxy resin, etc. Used, the functional group is "amino group"
In this case, polyisocyanate or epoxy resin is used.

(Conductive powder (M))
As the conductive powder (M), there is no particular limitation on the type and shape as long as solderability is obtained. For example, gold powder, silver powder, copper powder, silver-coated copper powder, silver-coated aluminum powder,
Silver coated nickel powder, nickel powder, aluminum powder, silver coated glass beads, tin oxide,
Various things including tin oxide-coated titanium oxide can be used, and two or more kinds can be used in combination. Silver powder, silver-coated copper powder, and a mixture of silver powder and silver-coated copper powder are representative examples of preferable ones.

(Percentage of conductive powder (M) in solderable layer (2))
The ratio of the conductive powder (M) in the solderable layer (2) made of the pressure-sensitive adhesive resin (R) with a high blend of the conductive powder (M) is that the conductive powder (M) is silver powder, copper powder, silver coat In the case of metal powder such as copper powder, it is about 83% by weight or more (preferably 85% by weight or more, particularly preferably 87% by weight or more) on a weight basis, and as long as the film strength is maintained, the conductive powder (M) The higher the ratio, the better, but the upper limit is about 97% by weight.

[Formation of solderable layer (2) on main body (1)]
-1-
The solderable layer (2) typically has a lower surface (conductive portion (1A) of the outer peripheral surface of the main body (1) having conductivity and elasticity described above. And a coating solution of a composition comprising a pressure-sensitive adhesive resin (R) in which the conductive powder (M) is highly blended.

-2-
1. At this time, a primer is blended on the side of the coating liquid of the composition comprising the pressure-sensitive adhesive resin (R) in which the conductive powder (M) is highly blended, and the bottom of the outer peripheral surface of the main body (1). Underside (conductive part (1
It is preferable to improve the adhesiveness between A) and A).
2. When forming the conductive part (1A) of the main body part (1), a primer is pre-mixed on the conductive part (1A) side, or after the formation of the conductive part (1A) of the main body part (1), the conductive part (1A) It is also preferable to apply a primer to the surface of 1A) from the viewpoint of improving the adhesion between the conductive portion (1A) of the main body portion (1) and the solderable layer (2). In the latter case, instead of applying a primer to the surface of the conductive part (1A),
It is also preferable to cause a functional group to appear in the irradiated portion by performing surface activation such as plasma irradiation.
3. In particular, when the above means 1 and 2 are used in combination, the adhesion between the conductive part (1A) of the main body part (1) and the solderable layer (2) is further improved. can get.

-3-
As a primer in the above, a coupling agent such as silane, titanate, aluminum, zirconium, and fatty acid, or a solution obtained by dissolving or dispersing the coupling agent in a solvent is preferable.

-4-
The “bottom part” of the bottom surface of the main body part (1) in the above means that the chip-like conductive structure of the present invention is applied to the cream solder (having some adhesiveness) formed on the printed circuit board. This refers to the portion of the main body (1) that faces the cream solder when the object is mounted and lightly adhered, and then the solder paste is soldered by reflowing the cream solder.

-5-
The pressure-sensitive adhesive resin (R) is composed of ethyl acetate (boiling point 77 ° C), toluene (boiling point 111 ° C).
Often, it is prepared or obtained in the form of a low boiling solvent solution. Therefore, when preparing a coating solution of a composition comprising a pressure-sensitive adhesive resin (R) highly blended with conductive powder (M), the boiling point is 140.
It is preferable to add a medium boiling point solvent of about ˜250 ° C. so that smooth coating and an appropriate drying rate can be obtained. Examples of medium boiling point solvents are ethylene glycol mono n-butyl ether (ie butyl cellosolve, boiling point 171 ° C.), ethylene glycol mono t-butyl ether (boiling point 152 ° C.), 3-methoxy-3-methyl-1-butanol (boiling point 174 ° C. ),
Diethylene glycol monoethyl ether (ie carbitol, boiling point 195 ° C.), diethylene glycol monobutyl ether (ie butyl carbitol, boiling point 230 ° C.), ethylene glycol monoethyl ether acetate (ie cellosolve acetate, boiling point 1)
56 ° C), ethylene glycol monobutyl ether acetate (ie butyl cellosolve acetate, boiling point 192 ° C), diethylene glycol monoethyl ether acetate (ie carbitol acetate, boiling point 217 ° C), diethylene glycol monobutyl ether acetate (ie butyl carbitol acetate, boiling point 247 ° C) , Dipropylene glycol monomethyl ether (boiling point 230 ° C.), diacetone alcohol (boiling point 169 ° C.)
), 1-methyl-2-pyrrolidone (ie, N-methylpyrrolidone, boiling point 202 ° C.), γ-
Butyrolactone (boiling point 204 ° C.), cyclohexanone (ie anone, boiling point 156 ° C.),
Examples include methylcyclohexanone (boiling point 170 ° C.), isophorone (boiling point 215 ° C.), xylene (boiling point 140 ° C.) and the like. In addition to the above-mentioned low-boiling solvent and medium-boiling solvent, a solvent having an intermediate boiling point can be used in combination.

[Conductive structure that can be soldered]
As described above, a layer that can be soldered to the main body (1) having conductivity and elasticity.
By forming (2), the target solderable conductive structure is produced.

The free surface of the solderable layer (2) in this conductive structure is substantially tack-free. In addition to the qualitative method of detecting the presence or degree of tack by finger touch, the tack measurement method uses a device that focuses on ball tack (rolling ball method), peel tack, and probe tack to quantify the degree of tack. However, it is desirable that there is no or virtually no tack even with the simplest finger touch. If there is a tack that can be felt by touching the finger, the pressure-sensitive adhesive resin exceeds the allowable amount on the surface of the free surface of the solderable layer (2).
(R) means the presence of the solderable layer (2) of the target conductive structure.
) And the reflowed solder between the conductive powder and the reflowed solder is insufficient, and it becomes impossible to achieve reliable soldering of the conductive structure.

The solderable conductive structure of the present invention is an EM that is automatically mounted on a printed circuit board (PCB).
It can also be used as a C gasket (conductivity and elasticity are required), other connection parts, electrode parts, and the like. It is also useful as a component that is soldered by a method other than automatic mounting.

  The following examples further illustrate the invention.

[Preliminary examination]
-1-
In order to demonstrate the solderability of the conductive structure of the present invention, a solderable layer (2) is provided on at least the bottom surface of the outer peripheral surface of the main body (1) having conductivity and elasticity. ) Is formed, and the conductive structure is mounted on cream solder (S) (adhesive enough to mount a chip) formed on the printed circuit board (PCB). Then, it is necessary to test whether the conductive structure is soldered when the cream solder (S) is reflowed. However, the following preliminary examination was conducted before such a test.

-2-
In this preliminary study, instead of looking at whether soldering is possible by placing the conductive structure on the cream solder (S) formed on the substrate and then reflowing the cream solder (S), Applyable layer (2) A conductive paste for forming is applied to a laminate for a substrate to form a film, and then a layer of cream solder (S) is applied and formed on the film. The solder (S) was heated to the reflow temperature to examine whether the melted cream solder (S) was compatible with the coating.
This study provides information on the effects of factors such as the composition of the coating solution (conductive paste) for forming the solderable layer (2), the type of solder, and the solder reflow temperature. Since it can be obtained relatively easily and visually, it can be said that it is suitable as a search or screening method.

-3-
The experiment by this preliminary examination method was performed in the following procedure.
Prepare a substrate (a laminated plate obtained by stacking a prepreg impregnated with a paper base material with an epoxy resin and pressurizing and heating) for use as a printed circuit board.
・ Solderable layer (2) In order to determine the composition of the conductive paste for forming, pressure-sensitive adhesive resin made of acrylic or acrylic rubber polymer, cross-linking agent for the polymer, metal powder (silver powder and silver Copper powder), a coupling agent, and a medium-boiling dilution solvent are selected, and one to three levels are selected for the amount of each component to prepare a conductive paste.
Next, these conductive pastes are applied onto the above laminate and dried to form a film having a thickness of about 30 μm.
Next, cream solder (flux-containing solder paste) is applied onto the coating to form a cream solder (S) layer having a rectangle of 7 mm length and 3 mm width and a thickness of about 140 μm. The solder layer at this stage does not have a metallic luster.
-After leaving in this state for one day, the layer of cream solder (S) is heated up to 260 ° C by infrared heating and reflowed, and then allowed to cool. When the reflowed cream solder and the above coating are well-suited (wet), the cream solder (S) layer becomes flat and has a silver luster. On the other hand, when the reflowed cream solder and the above-mentioned coating are not well-suited (wet), the cream solder (S) layer does not become flat and a part of the cream solder (S) layer becomes spherical. There are many things. Even when a part of the cream solder (S) layer is spheroidized, there are cases of small spheres and large spheres, and cases where the contact angle of the spheres is large and small. Empirically, the contact angle of the sphere when spheroidized is 90 °
In the case of exceeding, the conformity of the film to the reflowed cream solder is decisively inferior. On the other hand, even if the layer of cream solder (S) is spheroidized, if the contact angle of the sphere is less than 90 °, the familiarity of the film with the reflowed cream solder is not fatally inferior,
Soldering may be possible when the size of the sphere is small.
・ After obtaining the above preliminary experiments by first trying about 20 to 30 prescriptions, various findings were obtained, and then the preconditions considered to be relatively preferred were changed and further about 20 prescriptions were tried. The experiment was repeated, and finally, several prescriptions that could be put into practical use were reached from a total of about 400 experiments, and the following tests (Examples) described below were conducted with reference to the prescriptions.

[Examples 1 to 3]
From the above preliminary studies, we have obtained knowledge about the formulation of the coating liquid (conductive paste) suitable for forming the solderable layer (2) and the type of cream solder. The conductive paste was selected and applied to the bottom surface of the main body portion (1) to form the target conductive structure (solderable EMC gasket) for evaluation.

(Production of conductive and elastic body (1))
A total of 70 to 90 parts by weight of silver powder and silver-coated copper powder as an example of metal powder (M ′) with respect to 10 to 30 parts by weight of thermosetting grade silicone rubber (R ′) that can be extruded; A molding material 1 for forming a conductive part (1A) containing a small amount of a molding aid was prepared. In addition, a molding material 2 for forming a non-conductive part (1B) was prepared in which only the small amount of molding aid was contained in the same silicone rubber (R ′) as described above.

By supplying the molding material 1 and molding material 2 to the respective extruders of the two-color extrusion molding machine and performing melt extrusion molding, the outer peripheral side is the conductive part (1A) and the inner peripheral side is the non-conductive part (1B). Fig. 2 (A)
A long two-color extruded product having a hollow cross-sectional shape as described above was produced. As shown in FIG. 2A, the dimensions are 6 mm for W, 6 mm for H, 4 mm for D, 1 mm for t1, 1.4 mm for t2.
The thickness t3 of the conductive portion (1A) is 100 μm. h is a hollow part.

(Primer treatment on the bottom side of the main unit (1))
For the main body part (1) made of the two-color extrudate obtained above, first, a primer solution consisting of a solution obtained by diluting a silane coupling agent with a solvent is applied to the bottom surface of the bottom part side and dried, so that the bottom surface is covered. It became the primer-treated surface.

(Preparation of coating solution (conductive paste) for forming solderable layer (2))
As a solution of pressure-sensitive adhesive resin (R), n-butyl acrylate / acrylonitrile / 2-
A toluene / ethyl acetate solution of an acrylic rubber polymer (a glass transition point of −39 ° C. and a weight average molecular weight of 1.3 million) composed of a copolymer having a copolymerization ratio of hydroxyethyl acrylate of 85/10/5 by weight. (The solid content was 20% by weight).

In this solution, a polyisocyanate crosslinking agent (3 tolylene diisocyanate 3 mol) as a crosslinking agent for the above acrylic rubber polymer (crosslinking agent for 2-hydroxyethyl acrylate unit which is a functional group-containing monomer unit in the polymer). And 1 mol of trimethylolpropane), ethyl cellosolve acetate (boiling point 156 ° C.) was added for dilution, and a small amount of silane coupling agent was added.

Next, silver powder as a conductive powder (M) and silver-coated copper powder were blended into this solution to prepare a conductive paste as a coating liquid for forming a solderable layer (2).

(Formation of solderable layer (2) on main body (1))
This coating solution (conductive paste) is applied to the primer-treated surface of the bottom surface of the main body (1) prepared above and cured under conditions of a temperature of 150 ° C. for 30 minutes, whereby a thickness t4 is 30 μm.
The solderable layer (2) was formed. As a result, the conductive structure shown in FIG. 2B was obtained. The formed solderable layer (2) is flexible and follows the elastic main body (1), and the solderable layer (2) does not crack or peel off. . In this way, a desired solderable conductive structure (EMC gasket) was obtained.

(Evaluation)
The obtained conductive structure was examined for the presence of tack on the free surface of the solderable layer (2) by the finger touch method. The conductive structure cut into 8 mm length is placed on a cream solder (S) layer (adhesive) formed on the substrate and lightly adhered, and then the cream solder (S) When the layer was reflowed at a peak temperature of 260 ° C., it was observed whether the conductive structure moved or not moved from the mounting position, and the adhesive strength was measured after cooling. Table 1 shows the evaluation results together with the formulation of the coating liquid (conductive paste) for forming the solderable layer (2).
In Table 1, ◎ and ○ indicate pass, □ indicates acceptable, and Δ indicates acceptable. The user's desired spec (pass line) of the adhesive strength of the structure after the reflow operation is 0.8 kgf or more.

[Table 1]

(Notes on Table 1)
1. Table 1 shows the formulation and the amount (parts by weight) of each component. Since the ratio of the solid content of the acrylic rubber solution and the crosslinking agent solution is as shown in Table 1, the weight of the acrylic rubber and the crosslinking agent, which are the solid content in these solutions, can be calculated immediately.
2. The density of acrylic rubber (solid content) is 1.04, the density of cross-linking agent (solid content) is 1.04, the density of silver powder is 10.49, the density of silver-coated copper powder is 9.06, and the density of silane coupling agent is 1.00. The weight part of the component (solid content in the case of a solution) is determined. The total of parts by weight of each component is 10.59 parts by weight, 9.53 parts by weight, and 10.04 parts by weight in the order of Examples 1, 2, and 3 (excluding ethyl cellosolve acetate as a diluent solvent).
3. By dividing the weight part of each component by the density of each component, the volume of each component can be obtained, and the total volume of each component can also be obtained immediately. The total volume of each component is 2.
47, 1.44, and 1.94 (excluding ethyl cellosolve acetate, which is a diluting solvent).
4). The coating density is obtained by dividing the total weight of each component by the total volume of each component.
It becomes 4.28, 6.60, 5.16 in order of 2, 3.
5. The ratio of the total weight of the metal powder to the total weight of each component is the conductive powder filling rate on a weight basis, which is 85.0% by weight, 94.5% by weight, and 89.6% by weight in the order of Examples 1, 2, and 3.
6). The ratio of the total volume of the metal powder to the total volume of each component is the volume-based conductive powder filling rate, which is 37.8% by volume, 64.6% by volume, and 48.0% by volume in the order of Examples 1, 2, and 3.

[Example 4]
(Preparation of coating solution (conductive paste) for forming solderable layer (2))
As a solution of pressure-sensitive adhesive resin (R), “n-butyl acrylate / ethyl acrylate /
Acetic acid of acrylic copolymer for pressure-sensitive adhesives comprising a copolymer having a copolymerization ratio of “acrylic acid” of 90/17/3 by weight (glass transition point is −50 ° C., weight average molecular weight is 900,000). An ethyl solution was prepared.

To this solution, a polyisocyanate crosslinking agent (3 moles of tolylene diisocyanate and trimethylolpropane 1) as a crosslinking agent for the above acrylic copolymer (a crosslinking agent for an acrylic acid unit that is a functional group-containing monomer unit in the polymer). And an adduct with a mole)
Ethyl cellosolve acetate (boiling point 156 ° C.) was added for dilution, and a small amount of silane coupling agent was added.

Next, silver powder as a conductive powder (M) and silver-coated copper powder were blended into this solution to prepare a conductive paste as a coating liquid for forming a solderable layer (2). The formulation and filler filling rate were set to be the same as in Example 3 in Table 1.

(Formation of solderable layer (2) on main body (1))
By applying this coating liquid (conductive paste) to the primer-treated surface of the same main body (1) as in Examples 1 to 3, and curing it at a temperature of 150 ° C. for 30 minutes, t3
A 30 μm solderable layer (2) was formed. As a result, the conductive structure shown in FIG. 2B was obtained. The formed solderable layer (2) is flexible and has a resilient body
In addition to following (1), the solderable layer (2) did not crack or peel off. In this way, the target solderable conductive structure (EMC gasket)
was gotten.

(Evaluation)
About the obtained electroconductive structure, when the same evaluation as the case of Examples 1-3 was performed, the following preferable results were obtained.
-Solderable layer (2) touch tack: None (Evaluation)
・ Structure movement during solder reflow: None (Evaluation ○)
・ Adhesive strength of the structure after reflow: 1.21 kgf (evaluation ○)

[Example 5]
(Production of conductive and elastic body (1))
Composition for forming conductive part (1A) comprising a mixture of 10 to 30 parts by weight of liquid silicone rubber (R ') and a total of 70 to 90 parts by weight of silver powder and silver-coated copper powder as an example of metal powder (M') By preparing the product, sandwiching this composition between two carrier sheets (Asahi Glass Co., Ltd. fluororesin film “Aflex”, thickness 0.1 mm), rolling with a roll and then curing,
A main body portion (1) made only of a conductive portion (1A) having a thickness of 1 mm was produced.

(Formation of solderable layer (2))
Next, after peeling off one of the carrier sheets, the upper surface of the main body (1) (this surface will eventually become the lower surface of the bottom of the main body (1)) is primed with a silane coupling agent. Then, on the top surface, a solderable layer (2) having the same formulation as used in Example 2
The forming coating solution (conductive paste) was applied and dried to form a solderable layer (2).

As a result, a laminated sheet having a layer structure of “main part (1) made of conductive part (1A) / solderable layer (2) / carrier sheet” was obtained. The laminated sheet is cut into a predetermined width in the length direction to make a long product, and the carrier sheet is removed and cut in the width direction when necessary to form a chip component-like conductive structure (for example, an EMC gasket). be able to. This chip component can be smoothly soldered by mounting it on a solder layer of a printed circuit board (PCB) and reflowing the solder in a state.

Since the solderable conductive structure of the present invention has good solderability, it is particularly useful for the purpose of parts to be soldered by reflowing cream solder on a printed circuit board (PCB).

FIG. 5 is a cross-sectional view schematically showing the relationship between the main body (1) and the solderable layer (2) when obtaining the conductive structure of the present invention. (A) is sectional drawing of the main-body part (1) in Examples 1-3, (B) is sectional drawing of the electroconductive structure which provided the solderable layer (2) in the main-body part (1). is there. FIG. 5 is a cross-sectional view showing an example of the shape or structure of the main body (1).

(1) ... a main body having conductivity and elasticity;
(1A) ... conductive part, (1B) ... non-conductive part,
(M ') ... conductive powder, (R') ... component made of resin or rubber,
(2)… solderable layer,
(C1) ... coated film, (C2) ... dried film,
(M)… conductive powder, (R)… pressure sensitive adhesive resin,
(S)… Cream solder

Claims (7)

Having a structure in which a solderable layer (2) is provided on at least the bottom side of the outer peripheral surface of the main body (1) having conductivity and elasticity;
The main body (1) is composed of a conductive portion (1A) that is electrically connected between a bottom surface on the bottom side and a top surface on the top side, and
The solderable layer (2) is composed of a layer of pressure-sensitive adhesive resin (R) in which conductive powder (M) is highly blended,
Solderable conductive structure characterized by the above. 2. A solderable conductive structure according to claim 1, wherein the free surface of the solderable layer (2) is substantially tack free. 2. The solderable conductive structure according to claim 1, which is a structure that can be formed into a chip shape by cutting or cutting.   The solderable conductive structure according to claim 1, which is an EMC gasket. The solder according to claim 1, wherein the pressure-sensitive adhesive resin (R) in the solderable layer (2) is a pressure-sensitive adhesive resin (r) made of an acrylic polymer or an acrylic rubber polymer. A conductive structure that can be attached. Pressure-sensitive adhesive resin (r) comprising the above acrylic polymer or acrylic rubber polymer
6. A solderable conductive material according to claim 5, wherein said polymer has a functional group and has a glass transition point of −20 ° C. or less and further contains a crosslinking agent added to said acrylic polymer or acrylic rubber polymer. Sex structure. In the main body (1) having conductivity and elasticity, the main body (1) is composed of a conductive portion (1A) that is electrically connected between the bottom side surface and the top surface of the top portion. The solderable conductive property according to claim 1, wherein the conductive portion (1A) is composed of a composition in which a conductive powder (M ') is blended with a component (R') made of resin or rubber. Structure.