JP4159979B2 - Cover tape for packaging electronic parts - Google Patents

Description

  The present invention relates to a cover tape that can be heat-sealed out of a package that has the functions of protecting electronic components from contamination, arranging them for mounting on an electronic circuit board, and taking them out when storing, transporting, and mounting the electronic components. is there.

  In recent years, electronic components for surface mounting such as ICs, transistors, diodes, capacitors, and piezo-resistors have been continuously equipped with trays and pockets with embossed pockets that can be accommodated according to the shape of the electronic components. It is packaged and supplied in a package comprising a formed carrier tape and a cover tape that can be heat sealed to the carrier tape. The electronic components of the contents are automatically taken out from the carrier tape after the tray and cover tape are peeled off and are surface-mounted on the electronic circuit board.

  The strength at which the cover tape is peeled off from the carrier tape is referred to as peel strength. However, if the strength is too low, there is a problem that the cover tape is detached and the electronic components as contents are dropped when the package is transferred. Conversely, if it is too strong, the carrier tape vibrates when the cover tape is peeled off, causing a phenomenon of jumping out of the storage pocket immediately before the electronic component is mounted, that is, a jumping trouble.

At present, the peeling mechanism when peeling from a carrier tape of a commercially available cover tape is classified into three types: an interface peeling type, a transfer peeling type, and a cohesive failure type. The interfacial peeling type peels off the sealing surface of the cover tape and the carrier tape, the transfer peeling type means that the heat sealant layer itself is transferred to the carrier tape at the time of peeling, and the cohesive failure type means heat. It is of a type that peels when another layer different from the sealant layer or the heat sealant layer itself (hereinafter referred to as sealant) is torn. Compared only with the state when peeling the cover tape heat-sealed to the carrier tape, each type has advantages and disadvantages, but the interface peeling type has the same sealing surface and peeling surface, so the influence of the shape, material, and properties of the carrier tape Easy to receive, peel strength becomes unstable and cheap. In the transfer peeling type, the adhesive layer needs to be a thin film because of the mechanism, so-called heat sealing lacquer must be used, and the peeling strength tends to be sensitive to the sealing temperature, making it difficult to obtain an appropriate peeling strength. In the cohesive failure type, the adhesive layer and the release layer are different, so the peel strength is less dependent on the sealing conditions. Further, it has a great advantage that it is not affected by the shape, material, and properties of the carrier tape. However, since a layer different from the heat sealant layer is involved during peeling, layers other than the heat sealant layer may peel off. Further, it is difficult to set the position at which the sealant breaks, and the heat sealant layer remains on the surface of the carrier tape at the time of peeling, and the contents cannot be taken out (hereinafter referred to as delamination). Since the sealant is designed to be easily broken, it is often an alloy of a plurality of resins that are difficult to mix, and they may not be uniformly mixed, which may cause defects due to aggregates. For example, when an attempt is made to form a heat sealant layer using a blend of polyethylene, polystyrene, elastomeric styrene-butadiene-styrene or styrene-isoprene-styrene block copolymer shown in Patent Document 1, there are many aggregates. Therefore, the visibility in the inspection process after inserting a part in the pocket of a carrier tape and heat-sealing a cover tape worsens.
JP-A-56-041161

  In order to solve the above-mentioned problems, the present invention is to provide a cover tape in which the peel strength depends on the seal temperature, the change with time is small, and the sealability is stable.

The present invention
(1) A film composed of at least three layers of a heat sealant layer, an intermediate layer, and a base material layer. When the intermediate layer adjacent to the heat sealant layer is formed as a single film, the tensile strength in the TD direction is 2 to 10 N. a cover tape for packaging electronic parts, comprising a resin composition having a thickness of ² mm / mm2 or less,
(2) The cover tape for packaging electronic parts according to (1), wherein the peeling mechanism when peeling after sealing is a cohesive failure type in the intermediate layer,
(3) The intermediate layer is composed of one or more layers, and at least the intermediate layer adjacent to the heat sealant layer causes cohesive failure when it is peeled off after sealing, to 100 parts by weight of polyethylene having a melt flow rate of 10 to 30 g / 10 minutes In contrast, 5-100 parts by weight of polystyrene or methyl methacrylate-styrene copolymer having a melt flow rate of 10 to 60 g / 10 min, and hydrogenated styrene having a melt flow rate of 30 to 250 g / 10 min. The cover tape for packaging electronic parts according to (1) or (2), which is a resin composition to which 0 to 50 parts by weight of a butadiene-styrene block copolymer is added,
(4) The electronic component according to any one of (1) to (3), wherein the base material layer is a film obtained by laminating at least one film among biaxially stretched films of polyester, polypropylene, and nylon. Cover tape for packaging,
(5) The total thickness of the biaxially stretched film of the base material layer is 5 to 30 μm, the total thickness of the intermediate layer is 5 to 50 μm, and the thickness of the heat sealant layer is 0.2 to 3 μm (1 ) To (4), the electronic component packaging cover tape according to any one of
(6) The surface of at least one layer of the base material layer and the heat sealant layer is subjected to antistatic treatment, and the surface resistivity is 1 × 10 ^{4 to} 1 × 10 ¹³ Ω / □. The electron according to any one of claims 1 to 5 Cover tape for parts packaging,
The electronic device according to any one of (1) to (6), wherein a peel strength between the cover tape and a carrier tape in which pockets for storing electronic components are continuously formed is 10 to 120 cN per 1 mm of the seal width. Cover tape for parts packaging,
It is.

  According to the present invention, the peel strength can be arbitrarily set in the range of 10 to 120 cN per mm. In addition, the cover tape with the conventional peeling mechanism of the interfacial peeling type or the transfer peeling type has a problem that the peeling strength is largely dependent on the sealing conditions, a problem that changes over time depending on the storage environment, etc. Since the peeling is based on the cohesive failure type, a cover tape having a stable peel strength can be obtained.

  Components of the cover tape 1 of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing the layer structure of the cover tape of the present invention. FIG. 2 is a cross-sectional view showing a use state of the cover tape of the present invention heat-sealed to a carrier tape. The base material layer 2 is a biaxially stretched film made of polyester, polypropylene, or nylon, and is a transparent and highly rigid film having a thickness of 5 to 30 μm. When the thickness is 5 μm or less, the rigidity is lost and the cover tape is easily cut. If it exceeds 30 μm, it is too hard and the seal becomes unstable.

The intermediate layer 3 includes one or more layers, and includes at least an intermediate layer 3B adjacent to the heat sealant layer as a layer that causes cohesive failure when peeled after sealing. In addition, the intermediate layer 3A may be included as a layer that can also serve as a cushion.
The intermediate layer 3B is made of a resin composition having a tensile strength in the TD direction of ² to 10 N / mm ² when a single film is formed, and causes cohesive failure when peeled after sealing. When the tensile strength in the TD direction exceeds 10 N / mm ² , the cohesive strength of the layer is strong, and cohesive failure does not occur during peeling. On the other hand, if it is lower than ² N / mm ² , the cohesive force of the layer is weak, and cohesive failure tends to occur, and the desired strength cannot be obtained. This resin composition comprises polystyrene, polymethyl methacrylate or methyl methacrylate-styrene having a melt flow rate of 10 to 60 g / 10 min with respect to 100 parts by weight of polyethylene having a melt flow rate of 10 to 30 g / 10 min. It is a film comprising 5 to 100 parts by weight of a copolymer and 0 to 50 parts by weight of a hydrogenated styrene-butadiene-styrene block copolymer having a melt flow rate of 30 to 250 g / 10 min. As the method for forming the intermediate layer, the extrusion laminating method is inexpensive and desirable from the viewpoint of hygiene. The melt flow rate of polyethylene is less than 10 g / 10 minutes, or the melt flow rate of polystyrene or methyl methacrylate-styrene copolymer is less than 10 g / 10 minutes, or the melt of hydrogenated styrene-butadiene-styrene block copolymer. When the flow rate is less than 30 g / 10 minutes, if an extrusion laminating method is used as a processing method, the spreadability of the film is small and appropriate film formation cannot be performed. In addition, the melt flow rate of polyethylene exceeds 30 g / 10 minutes, the melt flow rate of polystyrene or methyl methacrylate-styrene copolymer exceeds 60 g / 10 minutes, or the hydrogenated styrene-butadiene-styrene block copolymer. When the melt flow rate of the polymer exceeds 250 g / 10 minutes, the necking is severe and an appropriate film cannot be formed. When the content of the methyl methacrylate-styrene copolymer is less than 5 parts by weight with respect to 100 parts by weight of polyethylene, cohesive failure of the intermediate layer does not occur. When the amount exceeds 100 parts by weight, mixing is worsened and film formation becomes impossible. When the content of the hydrogenated styrene-butadiene-styrene block copolymer exceeds 50 parts by weight with respect to 100 parts by weight of polyethylene, the thickness of the film varies during extrusion lamination.

  Each layer of the cover tape 1 has a thickness of 5 to 30 μm for the base layer 2, 5 to 50 μm for the intermediate layer 3, and 0.2 to 3 μm for the heat sealant layer 4. If the thickness of the base material layer is less than 5 μm, the tape itself will be stiff and difficult to handle. When the thickness of the base material layer exceeds 30 μm, the tape becomes hard and may be peeled off when a twisting force is applied after taping the electronic component. Further, if the thickness of the intermediate layer is less than 5 μm by the extrusion laminating method, the thickness variation is large, and an appropriate peel strength cannot be obtained during heat sealing. If it exceeds 50 μm, delamination tends to occur during peeling. Moreover, when the thickness of the heat sealant layer is less than 0.2, there is a large variation in thickness when laminated by gravure coating or the like, and an appropriate peel strength cannot be obtained during heat sealing. When it exceeds 3 μm, the adhesive itself peels off at the time of peeling, and the peeling strength is not stable.

Antistatic treatment is applied to the surface of at least one of the base material layer and the heat sealant layer, and the surface resistivity is 1 × 10 ^{4 to} 1 × 10 ¹³ Ω / □. If the surface resistivity exceeds ^{4 1} × 10 ¹³ Ω / □, static electricity generated when vibration or friction is applied during transfer of the package or the like may damage the electronic components as contents. Also, if it is less than 1 × 10 ⁴ Ω / □, when the static electricity is generated, it is immediately conducted and the static electricity is released.

  The resin of the heat sealant layer is formed so that the peel strength between the cover tape 1 and the carrier tape 6 is 10 to 120 cN, preferably 10 to 90 cN, more preferably 20 to 70 cN per 1 mm of the seal width. When the peel strength is lower than 10 cN, there is a problem in that the cover tape is detached during transportation of the package, and the electronic component as the contents falls off. On the other hand, if it is higher than 120 cN, the carrier tape vibrates when the cover tape is peeled off, causing a phenomenon of jumping out of the storage pocket immediately before the electronic component is mounted, that is, a jumping trouble. According to the present invention, it is possible to obtain the desired performance with low dependence on the sealing conditions and with little change in peel strength over time due to the storage environment.

Examples of the present invention are shown below, but the present invention is not limited to these examples.
Using a biaxially stretched polyester film with a film thickness of 25 μm as the base material layer, the intermediate layer was formed into a film thickness of 30 μm by the extrusion laminating method (extrusion temperature: 280 ° C.) according to the formulation shown in Tables 1 and 2. As a heat sealant layer, polymethylmethacrylate was formed into a film thickness of 1 μm by a gravure coating method to obtain a cover tape having a layer structure shown in FIG.
After slitting the obtained cover tape to a width of 5.5 mm, heat sealing was performed with a carrier tape made of polystyrene having a width of 8 mm, and the peeling mechanism and the peeling strength were measured. The characteristic evaluation results are shown in Table 1 for the examples and Table 2 for the comparative examples together with the tensile strength measurement results of the intermediate layer.

The following symbols and display names in Tables 1 and 2 were used.
PET-G: Copolyester
(6763 manufactured by Eastman Chemical Company)
PE1: Polyethylene
(L211 by Sumitomo Chemical Co., Ltd.)
PE2: Polyethylene
(MFR = 25 g / 10 min, GA807 manufactured by Sumitomo Chemical Co., Ltd.)
PS: Polystyrene
(MFR = 10 g / 10 min Nippon Polystyrene G440K)
MS: Methyl methacrylate-styrene copolymer
(MFR = 13g / 10min KS-10 manufactured by Nippon Steel Chemical Co., Ltd.)
PMMA: Polymethylmethacrylate
(MFR = 14g / 10min MF001 manufactured by Mitsubishi Rayon Co.)
SEBS: Styrene-ethylene-butadiene-styrene copolymer
(MFR = 150 g / 10 min Asahi Kasei Kogyo H1031)

  The present invention relates to a cover tape that can be heat-sealed out of a package that has the functions of protecting electronic components from contamination, arranging them for mounting on an electronic circuit board, and taking them out when storing, transporting, and mounting the electronic components. is there.

It is sectional drawing which shows the layer structure of the cover tape of this invention. It is sectional drawing which heat seals the cover tape of this invention to a carrier tape, and shows the use condition.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cover tape 2 Base material layer 3 Intermediate | middle layer 3A The layer which can also play the role of a cushion 3B The layer adjacent to a heat sealant layer 4 Heat sealant layer 5 Sealing part 6 Carrier tape

Claims (5)

A cover tape for packaging electronic parts comprising at least three layers of a heat sealant layer, an intermediate layer, and a base material layer,
The intermediate layer adjacent to the heat sealant layer has a melt flow rate according to JIS K7210 of 10 to 60 g / per 100 parts by weight of polyethylene resin with a melt flow rate according to JIS 6922-1 of 10 to 30 g / 10 min. 5 to 100 parts by weight of methyl methacrylate-styrene copolymer resin for 10 minutes, and hydrogenated styrene-butadiene-styrene block having a melt flow rate of 30 to 250 g / 10 minutes according to ISO 1133 (230 ° C., 2.16 kg) It is a resin composition (A) added with 0 to 50 parts by weight of a copolymer,
The resin composition (A) is a resin composition having a tensile strength in the TD direction of ² to 10 N / mm ² when a single film is formed .
A cover tape for packaging electronic parts, wherein the peeling mechanism when peeling after heat sealing is a cohesive failure type in the intermediate layer . The cover tape for electronic component packaging according to claim 1, wherein the base material layer is a film in which at least one kind of a biaxially stretched film of polyester, polypropylene, or nylon is laminated. The total thickness of the biaxially stretched film of the base material layer is 5 to 30 µm, the total thickness of the intermediate layer is 5 to 50 µm, and the thickness of the heat sealant layer is 0.2 to 3 µm. The cover tape for electronic component packaging as described. The surface of at least one layer of the base material layer and the heat sealant layer is subjected to antistatic treatment, and the surface resistivity is 1 × 10 ⁴ to 1 × 10 ¹³ Ω / □. Cover tape for packaging electronic parts. The cover tape for packaging electronic parts according to any one of claims 1 to 4, wherein a peel strength between the cover tape and a carrier tape in which pockets for storing electronic parts are continuously formed is 10 to 120 cN per 1 mm of seal width.

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