JP2005306460A - Cover tape and electronic part packaging carrier tape system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cover tape that sufficiently restrain corrosion of the metal part of an electronic part even when the electronic component is stored for a long time in an environment that has a high temperature and a high humidity, and to provide an electronic component packaging carrier tape system that ensures stably appropriate peeling strength when the cover tape is peeled. <P>SOLUTION: The cover tape has on the surface of its heat seal layer an antistatic layer formed from an antistatic agent or antirust agent. The chip type electronic component packaging carrier tape system uses the cover tape. It is preferable that a benzotriazol compound is used as the antirust agent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cover tape used as a lid material for a container that accommodates a component having a metal portion, and a carrier tape system for packaging electronic components using the cover tape.

  A carrier tape is generally used to transport electronic components such as ICs. That is, the electronic component is inserted into a concave portion for storing an electronic component formed on the carrier tape at regular intervals, and a cover tape having an easily peelable adhesive layer on the base material is heated on the upper surface of the carrier tape. After sealing and enclosing the electronic component, it is wound into a reel and transported. The cover tape needs to be transparent enough to inspect the electronic component and can be easily and smoothly peeled off from the carrier tape. Further, the electronic component is easily broken down by static electricity such as an IC. In order to prevent troubles such as adhesion of the electronic parts to the cover tape and popping out when the cover tape is peeled off from the carrier tape, the dust is prevented from adhering to the contents, or the cover tape is peeled off from the carrier tape. Antistatic treatment is performed on one or both surfaces of the tape.

  For the antistatic treatment, methods such as kneading an antistatic agent into a resin constituting the surface to be imparted with antistatic properties, or applying a thin antistatic agent to the surface are used. The thing which apply | coated the antistatic agent to the surface of the contact bonding layer is disclosed by patent document 1 and 2, for example.

  Although these methods can provide an antistatic effect, when placed in a high temperature and humidity environment, the metal parts such as ICs that are the contents may corrode. When a nonionic antistatic agent is used as an antistatic agent, the occurrence of corrosion of the metal part is reduced, but even in that case, very few ions are present, and depending on the placed environmental conditions, the metal part Corrosion occurred and the improvement was demanded.

On the other hand, as the adhesive layer, a method of mixing conductive metal fine particles with a heat-adhesive resin has also been proposed (for example, Patent Documents 3 and 4). However, these methods have a problem in that it is difficult to confirm the shape of the contents because the transparency of the cover tape is lowered.
JP-A-11-115088 JP 9-156684 A Japanese Patent Laid-Open No. 7-251860 JP-A-11-115088

  The present invention provides a cover tape used for a lid of a container for storing a component having a metal part, and a carrier tape system for packaging an electronic component using the cover tape. It is an object of the present invention to provide an antistatic cover tape capable of sufficiently suppressing corrosion of a metal part of an electronic component even in a hot and humid environment, and a carrier tape system for packaging an electronic component using the same. .

  That is, the present invention is a cover tape having at least a base material layer and an easily peelable heat seal layer, and an antistatic layer comprising an antistatic agent and an antirust agent is formed on the surface of the heat seal layer. . It is preferable to use a benzotriazole compound as the rust inhibitor. On the other hand, the present invention is a carrier tape system for packaging electronic parts using the cover tape.

  In the carrier tape system using the cover tape of the present invention, even when an electronic component having a metal part is stored and stored in a high-temperature and high-humidity environment for a long time, corrosion of the electronic component can be sufficiently suppressed, and the electronic component is An appropriate peel strength when peeling the cover tape when taking out can be stably obtained.

  The cover tape of the present invention has at least a base material layer and an easily peelable heat seal layer. Here, “having” may be a two-layer structure of base material layer / heat seal layer, or a multilayer structure such as a base material layer / heat seal layer composed of two or more layers in which different materials are laminated. Means it may be.

  When the base material layer is a single layer, the base material layer is any of polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyolefin resins such as polypropylene, polyamide resins such as nylon, polystyrene resins, polyethylene resins and polycarbonate resins. A film formed from one or two or more thermoplastic resins, biaxially stretched films of these resins can be suitably used, and commercially available films can be used. Furthermore, a biaxially stretched polyethylene terephthalate film is more preferable in terms of transparency and toughness.

  In the present invention, polystyrene resin means polystyrene, high impact polystyrene, styrene-butadiene copolymer or hydrogenated product thereof, styrene-isoprene copolymer or hydrogenated product thereof, graft copolymer of styrene and ethylene, Styrene-butene-butadiene copolymer, methacrylic acid and styrene copolymer, etc. are polymers having a styrene unit in the molecular chain in a molar ratio of 1/2 or more. Can be used.

  Polyethylene resins are low density polyethylene, linear low density polyethylene, ultra low density polyethylene, ethylene-α olefin, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methyl acrylate copolymer. A polymer, an ethylene-ethyl acrylate copolymer, an ethylene-propylene rubber or the like having an ethylene unit in a molecular chain in a molar ratio of 1/2 or more, and using one or a mixture of two or more thereof Can do.

  The base material layer of the present invention forms a thermoplastic resin layer on the base material layer film for the purpose of adjusting the elastic modulus and strengthening the adhesive strength between the base material layer film and the heat seal layer. Two base material layers can be used. The resin used for this thermoplastic resin layer is not particularly limited as long as it is suitable for the above-mentioned purpose, but polyethylene is easy to obtain an effect corresponding to the above-mentioned purpose and is easy to form a layer. Series resins are preferable, and linear low-density polyethylene resins are more preferable. Further, a mixture layer of ethylene-α olefin and styrene-ethylene-butadiene copolymer or a mixture of ethylene-α olefin and low-density polyethylene is formed on the surface of the two-layered base material layer on the polyethylene resin layer side. It is also possible to form a base material layer having a three-layer structure in which a layer, a mixture layer of ethylene-α olefin and styrene-butadiene copolymer, or the like is laminated.

  The method for producing a base material layer having a multilayer structure according to the present invention can be obtained by laminating the films of the respective layers by a general dry lamination method or extrusion lamination method. In the lamination, a commonly used adhesive can be used to strengthen the adhesion between the layers. Examples of the adhesive usually used include an isocyanate adhesive and an ethyleneimine adhesive. The adhesive layer preferably has a thickness of 5 μm or less. When exceeding 5 micrometers, there exists a possibility that the tensile elasticity modulus of a base material layer may become high and handling property may fall.

  In the base material layer of the present invention, various additives such as antioxidants and lubricants that are usually used are added in order to obtain extrusion stability when forming a film, as long as the properties of each layer are not impaired. Also good.

  The heat seal layer is not particularly limited as long as it has a heat sealability with respect to the carrier tape and is made of a thermoplastic resin composition showing an easy peelability that can be easily peeled off during use. Ethylene-based polymers such as ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate, ethylene-α-olefin, styrene-g-ethylene polymer, impact-resistant polystyrene, styrene-butadiene block copolymer, polystyrene, styrene -Ethylene-butadiene-styrene copolymer, styrene-isoprene-butadiene-styrene-copolymer styrenic polymer alone or a mixture of two or more thereof can be used. Among these, a combination of a styrene-butadiene block copolymer, an ethylene-α olefin, and an impact-resistant polystyrene is particularly preferable as a material having a small difference in peel strength at the time of peeling and a smooth peel feeling.

  Furthermore, in order to impart antistatic properties to the heat seal layer itself, high molecular weight antistatic agents such as ionomers, polyester ether copolymers and ethylene oxide chain-g-polyacrylic acid, surfactant type cationic systems, anions , Zwitterionic and nonionic antistatic agents can be added.

  The heat seal layer of the present invention can be formed by a general method, for example, a method of forming a film by extrusion molding such as inflation molding or T-die extrusion, and the above resin is dissolved in a solvent in a base material layer film. It can be obtained by applying a coating method and an aqueous emulsion. When a film is formed by extrusion, a soft resin having a low tensile elastic modulus is extruded. Therefore, in order to enhance the extrusion stability, it is preferable to co-extrusion with a support layer. As the resin used for the support layer, a resin having high extrusion stability is preferably used. This support layer is a thermoplastic resin layer that is one layer of the multilayer base material layer in the cover film of the present invention, and preferably a low-density polyethylene resin or ethylene-α-olefin and styrene-ethylene-butadiene copolymer. A mixture mixture, a mixture layer of ethylene-α olefin and low density polyethylene, a mixture layer of ethylene-α olefin and styrene-butadiene copolymer, or the like can be used.

  The film for heat seal layer obtained by the extrusion molding can be laminated with a base material layer by a general method such as dry lamination or extrusion lamination to form a cover tape. In addition, in order to suppress adhesion (blocking phenomenon) between the heat seal layer and the base material layer, a filler is added as an anti-blocking agent within the range that does not impair the transparency, while the surface of the heat seal layer is drawn into the extruded film. The surface roughness of the take-up roll during removal can be adjusted.

  In the cover tape of the present invention, an antistatic layer comprising an antistatic agent and a rust preventive agent is formed on the surface on the heat seal layer side. Antistatic agents used include various water-soluble surfactant type antistatic agents such as cationic, anionic, zwitterionic, and nonionic types, and high molecular weight charges such as those in which the above hydrophilic groups are bonded to high molecular weight chains. An inhibitor or the like can be diluted with a solvent such as water. In particular, from the viewpoint of workability, it is preferable to use an aqueous solution of a water-soluble antistatic agent.

  On the other hand, the rust inhibitor is not particularly limited as long as it is added to the antistatic agent diluent and uniformly dispersed or dissolved in the antistatic agent diluent. It is possible to use the anti-corrosion agent without impairing the performance of the anti-corrosion agent because it can be used in combination with the water-soluble anti-static agent. It is preferable as a rust inhibitor used in the present invention.

As a method for forming the antistatic layer, a mixed solution (preferably an aqueous solution) of at least one kind of the above antistatic agent and at least one kind of rust preventive agent is kissed on the surface of the cover tape on the heat seal layer side. It can be obtained by applying and drying by a general method such as reverse coater, Meyer bar coater, micro gravure coater or spraying. The thickness of the antistatic layer is preferably 0.01 to 0.2 μm. If it is less than 0.01 μm, sufficient antistatic properties cannot be obtained, and if it exceeds 0.2 μm, there is a risk of adversely affecting the heat sealing properties such as a decrease in peel strength. In order to obtain sufficient antistatic properties, the surface resistivity is preferably 1 × 10 ¹² Ω / □ or less. If it exceeds 1 × 10 ¹² Ω / □, sufficient antistatic performance may not be exhibited. From the viewpoint of antistatic, the surface resistivity is too low to cause a problem, but it is not realistic to obtain less than 1 × 10 ⁷ Ω / □ by adding an antistatic agent.

  The total thickness of the cover tape of the present invention is 40 to 75 μm. If it is less than 40 μm, it is easy to cut when the cover tape is peeled off at a high speed, and if it exceeds 75 μm, the volume after heat sealing the cover tape to the carrier tape increases, the amount that can be wound around one reel is reduced, and the production efficiency is lowered. .

  The cover tape of the present invention is used as a carrier tape for transporting electronic components in combination with a carrier tape containing electronic components. The carrier tape is obtained by molding a pocket for storing electronic components from a sheet-like molded product by a method such as a pressure forming method or a vacuum forming method. And it is comprised from the 1 type, or 2 or more types of resin component of a polystyrene-type resin, a polycarbonate resin, and a polyester resin. These resins can be blended and used in a single layer structure. For example, both surface layers may be a laminated structure such as a polycarbonate resin layer and the middle core may be a polystyrene resin layer. In addition, for the purpose of preventing troubles caused by static electricity, a carrier tape having antistatic performance retained can be used. In order to maintain the antistatic performance, a carrier tape kneaded with carbon black or an antistatic agent or a carrier tape coated on the surface is preferably used.

  The carrier tape system as used in the present invention means that the electronic component is housed in the carrier tape as described above, the cover tape is heat-sealed and covered, and the cover tape is peeled off by a mounting machine called a mounter while the component is mounted on the substrate. This is a system for transporting / mounting electronic components to be mounted on. In the carrier tape system of the present invention, even when an electronic component having a metal part is stored and stored in a high-temperature and high-humidity environment for a long time, the electronic component does not corrode, and the cover tape is peeled off when the electronic component is taken out. The appropriate peel strength can be stably obtained.

Examples and Comparative Examples of the present invention are shown below.
(Example 1)
15 parts by mass of a styrene-butadiene copolymer having a styrene content of 40% by mass (trade name: STR1602 manufactured by JSR) and 37 parts by mass of low-density polyethylene (trade name: Sumikasen L705, manufactured by Sumitomo Chemical Co., Ltd.) and impact resistance A resin mixture consisting of 10 parts by weight of a conductive polyethylene (trade name: H870, manufactured by Toyo Styrene Co., Ltd.) and a styrene-butadiene copolymer (trade name: L760, manufactured by Denki Kagaku Kogyo Co., Ltd.) having a styrene content of 80% by mass. A heat seal layer film having a thickness of 30 μm was prepared by a T-die method. At that time, the surface was brought into contact with an embossing roll, and a surface roughness of 0.4 μm (Ra) was imparted to the surface which is the outside of the cover tape. This film and a biaxially stretched polyethylene terephthalate film were subjected to extrusion sand lamination with molten low-density polyethylene to prepare a laminate film. As antistatic agent on both surfaces of this laminate film, a zwitterionic antistatic agent (manufactured by Nippon Pure Chemicals Co., Ltd., trade name: Julimer) is diluted 20 times with pure water (5 mass% solution) as a rust inhibitor. As a cover tape, 1 wt% of benzotriazole was added at a thickness of 0.2 μm and dried.

The following measurements were performed using the obtained cover tape.
(1) Surface resistivity measurement According to JIS K-6911, the surface resistivity of the heat seal layer surface was measured at an applied voltage of 500 V and a measurement time of 60 seconds in an environment of 23 ° C. and 50% RH. In general, the surface resistivity necessary for exhibiting the antistatic performance of the cover tape is 1 × 10 ¹² Ω / □ or less.
(2) Comparison of corrosiveness to metal In an accelerated environment (60 ° C. and 90% RH), a small piece of Kovar was placed on the heat seal layer surface of the cover tape, and the appearance of the contact surface with the cover tape was observed every 24 hours. Appearance observation was magnified 20 times with a stereomicroscope, compared with the surface not touching the cover tape, observed the occurrence of reddish brown discoloration, and measured the elapsed time until the occurrence. If no discoloration is observed for 192 hours or more in the accelerated environment, it has been confirmed that the same discoloration is not seen over half a year when actually handled in the market.
(3) Peel strength stability The carrier tape formed using a Denka EC sheet is heat-sealed under the following conditions using a heat sealing machine, and the cover tape is peeled off at a speed of 300 mm / min. Strength measurement was performed. Under these conditions, those having a peel strength of less than 0.4 N do not have sufficient sealing performance in practice.
Iron width: 0.5mm x 2 Seal pressure: 0.34MPa
Sealing temperature and time: 160 ° C x 0.5 seconds Number of sealings: 2 times

(Example 2)
A cover tape was prepared in the same manner as in Example 1 except that an anionic antistatic agent (trade name: electro stripper manufactured by Kao Corporation) was used as the antistatic agent, and the same evaluation was performed.
(Example 3)
A cover tape was prepared in the same manner as in Example 1 except that carboxybenzotriazole was used as a rust inhibitor, and the same evaluation was performed.

(Comparative Example 1)
A cover tape was prepared and evaluated in the same manner as in Example 1 except that the antistatic layer was formed without adding benzotriazole to the antistatic agent.
(Comparative Example 2)
A cover tape was prepared in the same manner as in Example 1 except that the antistatic agent was diluted 50 times and benzotriazole was not added, and the same evaluation was performed.
(Comparative Example 3)
A cover tape was prepared in the same manner as in Example 1 except that the antistatic agent was not applied, and the same evaluation was performed.
(Comparative Example 4)
A cover tape was prepared in the same manner as in Example 1 except that 2,4,6-trimercapto-s-triazine was used as a rust inhibitor, and the same evaluation was performed.
(Comparative Example 5)
A cover tape was produced in the same manner as in Example 1 except that 3- (2-benzothiazylthio) propionic acid was used as a rust inhibitor, and the same evaluation was performed.

  The evaluation results of Examples 1 to 3 and Comparative Examples 1 to 5 are shown in Table 1 and Table 2, respectively.

Claims (3)

A cover tape having at least a base material layer and an easily peelable heat seal layer, and having an antistatic layer comprising an antistatic agent and an antirust agent formed on the surface of the heat seal layer. The cover tape according to claim 1, wherein a benzotriazole-based compound is used as a rust inhibitor. A carrier tape system for packaging electronic parts using the cover tape according to claim 1.