JP2006117285A - Cover tape and carrier tape system for electronic component packaging - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cover tape capable of sufficiently preventing corrosion of a metallic part of an electronic component even if the component is stored under high temperature and highly humid conditions for a long time, and a carrier tape system for electronic component packaging capable of stably obtaining proper peel strength when peeling the cover tape. <P>SOLUTION: The cover tape has an antistatic layer made of an antistatic agent and a rust-preventive agent formed on the surface on a side of a heat seal layer, and the carrier tape system for a chip-type electronic component packaging employs the cover tape. An antistatic agent containing quaternary ammonium salt, polyoxyethylene alkyl ether and a benzotriazole-based compound is preferably used as the antistatic agent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cover tape used as a lid material for a container for housing a part having a metal portion, and a carrier tape system for packaging electronic parts using the cover tape.

  In general, a carrier tape is used to convey a chip-type electronic component such as an IC. That is, the chip-type electronic component is inserted into a concave portion formed in the carrier tape so as to accommodate the electronic component, and a cover tape having an adhesive layer on the base material is heat-sealed on the upper surface of the carrier tape. Then, after enclosing the electronic component, it is wound up in a reel shape and conveyed. 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 high-humidity environment, metal parts such as ICs as 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-11-351157 JP 2001-171727 A Japanese Patent Laid-Open No. 7-251860 JP-A-11-115088

  The present inventors store and store the parts in a cover tape used for a lid of a container for storing a part having a metal part and a chip-type electronic component packaging carrier tape system using the cover tape. In particular, it is an object of the present invention to provide a cover tape and a carrier tape system for packaging electronic parts using the cover tape that can sufficiently suppress the corrosion of the metal part of the component even in a hot and humid environment. A cover tape is proposed in which an antistatic layer comprising an antistatic agent and a rust inhibitor is formed on the surface of the cover tape on the heat seal layer side (Japanese Patent Application No. 2004-129131). In addition to the above-described problems of the present invention, an object of the present invention is to provide a cover tape having excellent antistatic properties and a carrier tape system for packaging chip electronic components using the same.

  That is, the present invention has at least a base material layer and a heat seal layer, and on the surface on the heat seal layer side, (a) a zwitterionic surfactant quaternary ammonium salt, (b) polyoxyethylene alkyl ether and (c ) A cover tape on which an antistatic layer containing a benzotriazole-based compound is formed. The antistatic agent layer comprises 20 to 70% by mass of component (a), 1 to 10% by mass of component (b), And it is preferable to contain 10-40 mass% of (c) component. On the other hand, the present invention is a carrier tape system for chip-type electronic component packaging using the cover tape.

  The carrier tape system using the cover tape of the present invention has a good antistatic effect, and sufficiently suppresses corrosion of electronic parts even when storing electronic parts with metal parts and storing them in a high temperature and high humidity environment for a long time. In addition, it is possible to stably obtain an appropriate peel strength when the cover tape is peeled off when the electronic component is taken out.

  The cover tape of the present invention has at least a base material layer and a 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. May be.

  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 polymer, 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.

  In the heat seal layer composed of such a resin, when the mixed resin is 100% by mass, the styrene-butadiene block copolymer is 30 to 80% by mass, the ethylene polymer resin is 15 to 60% by mass, It is more preferable to use a mixture having a blending ratio of 3 to 15% by mass of the impact-resistant polystyrene resin in terms of the stability of the peel strength.

  The cover tape of the present invention has a specific antistatic layer on the surface on the heat seal layer side as described later, but from the viewpoint of durability of antistatic properties, an ionomer, a polyester ether copolymer, and an ethylene oxide chain- A high molecular weight antistatic agent such as g-polyacrylic acid or a surfactant type cationic, anionic, zwitterionic or nonionic antistatic agent 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.

  The cover tape of the present invention has an antistatic layer formed on the surface on the heat seal layer side. This antistatic layer contains (a) zwitterionic surfactant quaternary ammonium salt as antistatic agent and (b) polyoxyethylene alkyl ether and (c) benzotriazole-based compound as main components. . Each of the above components is essential, and as the component (a), the quaternary ammonium salt can obtain a lower surface resistivity than other antistatic agents such as alkyldiethanolamine. In addition, the presence of the benzotriazole-based compound of component (c) provides an effect of suppressing the corrosion of metal parts such as ICs contacting the heat seal layer, but the presence of component (b) further increases A great effect of inhibiting corrosion is obtained. (C) A benzotriazole-based compound is a derivative such as benzotriazole or carboxybenzotriazole, and for example, other rust preventives such as triazine-based or propion-based rust preventives have sufficient rust-preventing effect or surface resistance. The rate is not obtained.

  The blending ratio of the components (a), (b) and (c) in the antistatic layer is preferably 20 to 70% by mass of the component (a) with respect to the entire composition. If it is less than 20% by mass, it is difficult to obtain a surface resistivity that provides a sufficient antistatic effect. On the other hand, the component (c) is preferably 10 to 40% by mass. When the amount is less than 10% by mass, the above-described effect of inhibiting metal corrosion may be insufficient. When the amount exceeds 40% by mass, it is difficult to obtain sufficient peel strength when heat-sealed with a carrier tape. There is. The component (b) is preferably 1 to 10% by mass. If the amount is less than 1% by mass, the effect of increasing the antirust effect of the component (c) may not be obtained. If the amount exceeds 10% by mass, sufficient peel strength is obtained when heat-sealed with the carrier tape. May be difficult. Further, as long as the effect of the present invention is not impaired, the antistatic layer may contain other surfactants such as alkyl betaines as components other than (a), (b) and (c). Good.

As a method for forming the antistatic layer of the present invention, the antistatic agent (preferably an aqueous solution) is applied to the surface of the cover tape on the heat seal layer side, a kiss reverse coater, a Meyer bar coater, a micro gravure coater, a spray or the like. It can be obtained by applying and drying by a general method. 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. .

  The cover tape of the present invention is used as a carrier tape for transporting electronic components in combination with an embossed tape containing electronic components. The embossed tape is formed by molding a pocket for housing 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 configuration. 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. Further, for the purpose of preventing troubles caused by static electricity, an embossed tape having antistatic performance maintained can be used. In order to maintain the antistatic performance, an embossed tape kneaded with carbon black or an antistatic agent or an embossed tape coated on the surface is preferably used.

  The carrier tape system as used in the present invention means that an electronic component is housed in the embossed 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 composed 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. 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. 2% by mass of polyoxyethylene oleyl ether and 78% by mass of zwitterionic antistatic agent SAT-6C (manufactured by Nippon Pure Chemicals) containing 50% by mass of a quaternary ammonium salt as an antistatic agent on both surfaces of the laminate film, A solution obtained by adding 20% by mass of benzotriazole and diluting 20 times with pure water (5% by mass solution) was applied to 0.2 μm and dried to obtain a cover tape.

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 required to exhibit 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. In addition, if no discoloration is observed for 336 hours or more in the accelerated environment, it has been confirmed that the same discoloration is not observed over one year when actually handled in the market.
(3) Peel strength stability Using a heat sealer, 24 mm molded with Denka EC sheet under the conditions of iron width 0.5 mm x 2 pieces, pressure 0.34 MPa, time 0.5 seconds, number of seals 2 times A taped product was prepared for the embossed tape having a width, peeled at a speed of 300 mm / min, and peel strength was measured. Even if the peel strength is sealed at a seal temperature of 160 ° C., those having a peel strength of less than 0.4 N may not have sufficient peel strength in practice.

(Example 2)
A cover tape was prepared in the same manner as in Example 1 except that SAT-4C (manufactured by Nippon Pure Chemical Co., Ltd.) was used as an amphoteric ion antistatic agent containing 20% by mass of a quaternary ammonium salt, 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.
Example 4
A cover tape was prepared in the same manner as in Example 1 except that the amount of polyoxyethylene oleyl ether added was 10 parts by weight, and the same evaluation was performed.
(Example 5)
A cover tape was prepared and evaluated in the same manner as in Example 1 except that the amount of benzotriazole added was 10 parts by weight.

(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 produced in the same manner as in Example 1 except that the antistatic layer was formed without adding polyoxyethylene oleyl ether to the antistatic agent, and the same evaluation was performed.
(Comparative Example 3)
A cover tape was prepared in the same manner as in Example 1 except that alkyldiethanolamine was used in place of the quaternary ammonium salt as the antistatic agent, 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 instead of benzotriazole as an additive, 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 instead of benzotriazole as an additive, and the same evaluation was performed.

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

Claims (3)

  It has at least a base material layer and a heat seal layer, and on the surface on the heat seal layer side, (a) a zwitterionic surfactant quaternary ammonium salt, (b) polyoxyethylene alkyl ether and (c) benzotriazole compound The cover tape in which the antistatic layer containing is formed.   The antistatic agent layer contains 20 to 70% by mass of component (a), 1 to 10% by mass of component (b), and 10 to 40% by mass of component (c). The cover tape according to 1.   A carrier tape system for packaging chip electronic components using the cover tape according to claim 1.