JPH10278966A - Cover tape for electronic component carrier - Google Patents

Abstract

(57) Abstract: In a cover tape bonded to an electronic component carrier tape, mounting travel due to electrostatic attraction of the electronic component due to charging on the bonding surface side and static electricity of the electronic component. Breakage is prevented by the dielectric phenomenon mechanism without depending on the mixing of an antistatic agent or conductive fine particles into the adhesive. An electrostatic functional layer (A), which acts to cancel the lines of electric force based on the charged electric charge by dielectric polarization with respect to the electric charge on the adhesive surface (2) side, for example, at least a carboxyl group and a quaternary ammonium in the side chain A coating film of a crosslinkable acrylic copolymer having a base is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antistatic cover tape for a tape carrier for carrying electronic components such as ICs and chip capacitors.

[0002]

2. Description of the Related Art As a tape carrier for carrying ICs, chip capacitors, and the like, electronic components are provided in holes of a carrier tape having holes provided at substantially equal intervals in the longitudinal direction of a tape-shaped cardboard carrier. A sandwich-type carrier for heating and bonding a cover tape provided with an adhesive layer which does not exhibit adhesiveness at room temperature on the upper and lower surfaces of the tape-shaped cardboard carrier, and a pocket for storing electronic parts. An electronic component is housed in a pocket of a carrier tape formed by embossing at substantially equal intervals in a longitudinal direction, and a cover tape provided with an adhesive layer which does not exhibit adhesiveness at room temperature is bonded to the carrier tape by heating. In an embossed carrier or an embossed carrier, an adhesive layer is provided over the entire width of the cover tape, and a non-adhesive film is adhered to a portion of the pocket width of the adhesive layer. I have.

When electronic components are assembled and transported to the site by such a tape carrier, the cover tape is peeled off from the carrier tape, and the electronic components are continuously taken out and mounted on an electronic circuit board. If the static electricity is generated by the repeated friction and contact caused by the vibration of the stored electronic components during the transport of the above electronic components,
Due to the electrostatic charge, the electronic components may be electrostatically attracted to the cover tape side, causing a mounting trouble. In addition, there is a fear that electrostatic breakdown may occur in recent advanced semiconductor components.

In order to eliminate such a problem, an antistatic treatment is usually applied to the adhesive surface side of the cover tape, and an antistatic agent (surfactant) is kneaded into the adhesive. It is also known to coat an antistatic agent on the surface of an adhesive layer, and to mix and disperse conductive fine particles in the adhesive.

[0005]

However, when a surfactant is used, the antistatic effect depends on the conductivity of the surfactant through the binding of water to the hydrophilic group, and the antistatic effect is high. Is unstable because it is affected by the environmental humidity, and a surfactant film is interposed at the bonding interface with the carrier tape, and depending on the selection of the surfactant, the bonding strength is destabilized. In particular, when a surfactant is coated on the surface of the adhesive layer, the coating film of the surfactant is easily peeled off by contact friction, and there is a problem in stability. On the other hand, in the case of mixing and dispersing the conductive fine particles in the adhesive, even if these disadvantages can be eliminated, the transparency of the cover tape will be impaired, which will hinder the confirmation of the stored electronic components. There is.

Accordingly, the present inventors have conducted intensive studies in order to eliminate the charging failure on the bonding surface side of the cover tape without depending on the use of the surfactant and the conductive fine particles. By interposing a layer of a crosslinkable acrylic copolymer having at least a carboxyl group and a quaternary ammonium group in a side chain (typically, a quaternary ammonium salt type (meth) acrylic resin) as an intermediate layer, -I knew that the charging failure on the tape bonding surface could be eliminated.

The inventors of the present invention have made intensive studies on the mechanism of eliminating the charging failure, and found that the quaternary ammonium salt type (meth) acrylic resin has a strong dipole moment and a high conductivity. It has been found.
That is, when the surface of the adhesive layer of the cover tape is charged by frictional contact, the dipole moment is applied to the resin of the quaternary ammonium salt type (meth) acrylic resin layer by the lines of electric force generated by the charged charges. Is induced, and this dipole mode
As a result, the lines of electric force (polarized finger lines) in the direction of canceling the lines of electric force are generated by the element, so that the lines of electric force generated by the charged charges are reduced. In this case, the quaternary ammonium salt type (meta) It has been found that the dipole moment is rapidly induced due to the high conductivity of the acrylic resin and the like, thereby preventing the electrostatic attraction and the occurrence of electric discharge due to the charged electric charge.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cover tape bonded to an electronic component carrier tape based on such knowledge, and to reduce mounting travel due to electrostatic attraction of the electronic component due to charging on the bonding surface side. An object of the present invention is to prevent electrostatic breakdown of an electronic component by a dielectric phenomenon mechanism without depending on mixing of an antistatic agent or conductive fine particles into an adhesive.

[0009]

SUMMARY OF THE INVENTION A cover tape for an electronic component carrier according to the present invention is a cover tape adhered to an electronic component carrier tape. On the other hand, an electrostatic functional layer that acts to cancel the lines of electric force based on the above-mentioned charged charges by dielectric polarization, for example, a coating film of a crosslinkable acrylic copolymer having at least a carboxyl group and a quaternary ammonium base in a side chain. It is a configuration characterized by comprising:

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a cover tape for an electronic component carrier according to the present invention, wherein 1 is a transparent plastic substrate, 2 is an adhesive layer (usually a heat seal type is used), Is an electrostatic function layer provided between the base material 1 and the adhesive layer 2 and acts so as to cancel lines of electric force based on the above-mentioned charged charges by dielectric polarization with respect to charging on the bonding surface side. It is. In the above embodiment, the electrostatic function layer is provided in the two-layer structure of the base material and the adhesive layer, but an anchor coat layer as an adhesion assistant is provided between the base material and the adhesive layer. It can also be provided. Further, an intermediate layer may be provided as an adhesion aid between the adhesive layer and the base material or for adjusting the rigidity of the cover tape.

2 (a) and 2 (b) show different examples of a cover tape for an electronic component carrier according to the present invention, wherein 1 is a base material and 2 is an adhesive layer (usually). , Heat seal type), A is the above-mentioned electrostatic function layer, 3 is an intermediate layer, and 4 is an anchor coat layer. In FIG. 1 and FIG.
The electrostatic function layer A also serves as an anchor coat layer.

The substrate 1 is biaxially stretched and has a thickness of 6 to 10.
A highly rigid transparent film of 0 μm can be used (6 μm
Is less rigid, and if it is 100 μm or more, it becomes too hard and the taping becomes unstable.) In particular, the thickness is 12 to 50 μm.
It is preferable to use the biaxially stretched polyethylene terephthalate film described above. The surface of the base material that is in contact with the anchor coat layer or the adhesive layer can be improved in adhesion with the anchor coat layer or the adhesive layer by surface treatment such as corona treatment, and the other surface is required. Depending on the conditions, an antistatic agent, a conductive paint, a release agent, or the like can be coated.

The adhesive layer 2 is not particularly limited in composition as long as it is a thermoplastic resin having transparency.
Polyethylene, ethylene-vinyl ester copolymer, ethylene-α, β-unsaturated carboxylic acid copolymer, ethylene-
α, β unsaturated carboxylic acid ester copolymer, ethylene-
Polyolefin resins such as α-olefin copolymers, (meth) acrylic resins, polyurethane resins, polyester resins, styrene block polymers, and diene polymers such as natural rubber and synthetic rubber can be used alone or in combination. A tackifier, a stabilizer, a lubricant, an antistatic agent, an antiblocking agent, and the like can be added to the adhesive in an amount that does not impair transparency, if necessary.

For the electrostatic function layer A, a quaternary ammonium salt type (meth) acrylic resin is preferably used, and an amine-based crosslinking agent, an epoxy-based crosslinking agent, and the like can be blended as required. . To form this electrostatic layer, a solution of a quaternary ammonium salt type (meth) acrylic resin using water or isopropyl alcohol as a solvent is applied by gravure coating, fountain coating, spraying or the like.
A drying method can be used, and the dry thickness is 1.5 to
0.3 μm.

The composition of the intermediate layer 3 is not particularly limited as long as it is transparent, and a thermoplastic resin having transparency, for example,
Polyethylene, ethylene-vinyl ester copolymer, ethylene-α, β-unsaturated carboxylic acid copolymer, ethylene-
α, β unsaturated carboxylic acid ester copolymer, ethylene-
Polyolefin resins such as α-olefin copolymers, (meth) acrylic resins, polyurethane resins, polyester resins and the like can be used alone or in combination of two or more.

For the anchor coat layer 4, a solvent type adhesive, for example, an isocyanate type adhesive can be used.

In the use of the cover tape according to the present invention, the surface of the adhesive layer is adhered to the carrier tape of the sandwich or embossed carrier of the electronic component.
During the transportation of electronic components, the adhesive layer surface is repeatedly subjected to friction and contact due to vibration of the stored electronic components, and static electricity is generated, and the lines of electric force generated by the static electricity generate a quaternary ammonium salt type (meta) of the electrostatic functional layer. The acrylic resin is polarized, and a dipole moment is induced. The generation of this dipole moment is a result of the electron distribution of the quaternary ammonium base being deviated in the direction of the line of electric force or the relative position between the ions fluctuating. Due to the high conductivity, the movement of these electrons and ions occurs quickly and dipole moment is induced with a short relaxation time. The direction of the lines of electric force based on the dipole moment is a direction in which the lines of electric force due to the triboelectricity on the surface of the adhesive layer are canceled out. The electric field lines on the surface can be reduced.
In the case of a quaternary ammonium salt type (meth) acrylic resin, the effect of this reduction is particularly large, and the line of electric force on the surface can be reduced, so that discharge and electrostatic adsorption on the surface of the adhesive layer can be prevented. Accordingly, it is possible to prevent the mounting component from being electrostatically attracted to the cover tape and the electronic component from being damaged by electrostatic discharge when the electronic component is mounted. This can be confirmed from the comparison between the following examples and comparative examples.

[0018]

【Example】

Example 1 A quaternary ammonium salt type (meth) acrylic resin and an epoxy resin were mixed in a ratio of 1: 1, and this mixture was mixed with a mixed solvent of isopropyl alcohol / water (mixing ratio: 2).
/ 1) was diluted and adjusted so that the solid content was 2% by weight to obtain a resin solution for electrostatic function. This solution is applied to a thickness of 12 μ
m on a single-sided corona-treated biaxially stretched polyester film is coated and dried so as to have a dry film thickness of 1 μm to form an electrostatic functional layer, and a low-density polyethylene is formed on the electrostatic functional layer as an intermediate layer. Is extruded at a thickness of 15 μm, and an EVA heat seal resin (V-3032 manufactured by DuPont-Mitsui Polychemicals Co., Ltd.) is extruded at a thickness of 25 μm onto the intermediate layer to form an adhesive layer. Was formed.

Example 2 An isocyanate-based adhesive was used as an anchor coat layer on a corona-treated surface of a biaxially stretched polyester film having a thickness of 12 μm and corona-treated on one side, so that the dry film thickness was 1 μm. A low-density polyethylene was extruded as an intermediate layer on the anchor coat layer at a thickness of 15 μm, and the surface of the polyethylene layer was corona-treated. The corona-treated surface was the same as in Example 1. 1 μm dry film thickness of resin solution for electrical function
m to form an electrostatic function layer, and extrude an EVA heat seal resin (V-3032 manufactured by DuPont-Mitsui Polychemicals Co., Ltd.) to a thickness of 25 μm on the electrostatic function layer. An adhesive layer was formed by coating.

Comparative Example 1 An isocyanate-based adhesive was used as an anchor coat layer on a corona-treated surface of a biaxially stretched polyester film having a thickness of 12 μm and corona-treated on one side, so that the dry film thickness was 1 μm. A low-density polyethylene as an intermediate layer is extruded with a thickness of 15 μm as an intermediate layer on the anchor coat layer, and the polyethylene layer surface is corona-treated. The corona-treated surface is EVA heat-sealed. A resin (V-3032 manufactured by Du Pont-Mitsui Polychemicals) was extruded and coated at a thickness of 25 μm to form an adhesive layer. [Comparative Example 2] A pellet obtained by uniformly mixing 2% by weight of a nonionic antistatic agent (Kao Corp., Electrostripper-TS3) with an EVA heat seal resin (V-3032, manufactured by DuPont-Mitsui Polychemicals Co., Ltd.) was used. Extrusion core with 25μm
Comparative Example 1 except that the adhesive layer was formed by coating.

For these examples and comparative examples,
Adhesive force to carrier tape (adhesive force when a cover tape slit to 5.3 mm in width is heat-sealed at 120 ° C. to an 8 mm wide polystyrene embossed carrier tape) and discharge by charging Voltage (5K on the adhesive side by static honest meter)
V was applied for 1 minute, and the charged voltage after 1 minute was read. However, at a temperature of 23 ° C. and a humidity of 65% RH), the electrostatic adsorption property for evaluating the mounting workability (rubbing the surface of the test piece 10 times with an insulating polyethylene terephthalate film, and approaching the tobacco ash to 1 mm) Table 1 shows the measurement results.

[0022]

[Table 1]

Regarding the chargeability, in each of the examples, the value was 0 as in Comparative Example 2 in which an antistatic agent was mixed with an adhesive.
Comparative Example 2 is a result in which the adhesive layer is conductive and the charged charges are discharged and dissipated. In the example, the effect of canceling the lines of electric force due to the dielectric polarization of the quaternary ammonium salt type (meth) acrylic resin layer is shown. According to the present invention, according to the present invention, as is clear from the measurement results of the adhesive force, the reduction in heat sealability of Comparative Example 2 due to the incorporation of the antistatic agent into the adhesive was eliminated, and the discharge was prevented. Obstacles (electrostatic breakdown of electronic components) can be eliminated. Regarding the electrostatic attraction, in each of the examples, there was no adhesion as in Comparative Example 2 in which an antistatic agent was mixed with an adhesive, and the electronic components were prevented from being electrostatically attached to the cover tape during mounting. As a result, the electronic components can be smoothly taken off, and good mounting workability can be secured.

[0024]

According to the cover tape for an electronic component carrier according to the present invention, failure due to electrification (such as mounting trouble or electronic component failure) can be achieved without performing antistatic treatment on the adhesive layer or the surface of the adhesive layer. (Electrostatic breakdown) can be prevented, obstacles due to charging can be eliminated, and stable adhesive sealability and easy see-through observation can be ensured.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of a cover tape for an electronic component carrier according to the present invention.

FIG. 2 is a view showing another embodiment of the cover tape for an electronic component carrier according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Adhesive layer A Electrostatic function layer

Claims (3)

[Claims] 1. A cover tape adhered to an electronic component carrier tape, which acts to cancel electric lines of force based on the above-mentioned charged electric charge by dielectric polarization with respect to the electric charge on the adhesive surface side. An electronic component carrier tape having an electrostatic function layer. 2. A cover tape for an electronic component carrier according to claim 1, further comprising at least a substrate made of a transparent plastic film, an adhesive layer, and an electrostatic function layer. 3. A cover tape for an electronic component carrier according to claim 1, wherein the electrostatic function layer is a crosslinkable acrylic copolymer having at least a carboxyl group and a quaternary ammonium group in a side chain.