JP2008074408A - Plastic sheet and carrier tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic sheet which is constituted in such a manner that on the surface of a base material layer consisting of a specified resin composition, an electrically-conductive layer is laminated, has antistatic properties, and has a high mechanical strength, and to provide a carrier tape which can package and store an electronic component being housed in the pocket while being thin, and can carry the electronic component without deformation or the like when the electronic component is mounted on a circuit board. <P>SOLUTION: For this carrier tape, the resin composition containing 1 to 20 pts.wt. of an AS resin and/or an MS resin based on 100 pts.wt. of an ABS resin is made into a base material layer. Then, a thin plastic sheet for which the electrically-conductive layer is laminated on at least one surface of the base material layer is thermally molded to form the carrier tape. The carrier tape packages the electronic component being housed in the pocket, can store the electronic component, and can carry the electronic component without deformation or the like when the electronic component is mounted on the circuit board. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention comprises a base material layer, a plastic sheet for packaging electronic parts having an antistatic property and a superior mechanical strength, molding processability, and the like, wherein a conductive layer is laminated on at least one surface of the base material layer, and The present invention relates to a carrier tape molded from the plastic sheet by thermoforming such as pressure forming, vacuum forming, vacuum pressure forming, press forming.

In response to rationalization of the production of electronic parts such as ICs and capacitors, and small volume, multi-product production, surface mounting is progressing, and mounting equipment that combines high density, high precision mounting, productivity, and high speed is required. The carrier tape is attracting attention as a packaging form suitable for packaging, storing and transporting electronic components, and aligning them for mounting on a circuit board and taking them out.
Recently, from the viewpoint of cost reduction, it is required to reduce the thickness of the plastic sheet for carrier tape molding, and the carrier tape molded from the thinned plastic sheet can be stored in the pocket without causing breakage or deformation. It is required to protect and store stored electronic components.
Also, in response to the demand to increase the speed of mounting electronic components on the circuit board, the carrier tape containing the electronic components is pitch-fed by the tape feeder of the mounting machine, and the electronic components stored by the transfer head are picked up. In the carrying-out process, the carrier tape is required to have as little clogging, deformation, bending, and breakage as possible.

In the field of electronic components, a plastic sheet is required to have mechanical strength so that it does not break or break even when it is thinned, and the carrier tape molded from the plastic sheet does not deform or break.
Also, the thickness of the pocket, which is a packaging container for carrier tape, is uniform, and the pocket corners are properly molded, and the end face of the plastic sheet when slitting into a tape or punching holes In addition, there is no need to have beards or burrs, and it is necessary to have good moldability and punchability.
Furthermore, the plastic sheet needs to be free from cutting and cracking when thermoformed on the carrier tape, and to be free from accidents such as cutting and cracking when punching holes. That is, the plastic sheet needs to have a certain level of mechanical strength, impact resistance, bending strength, and moldability.

Conventionally, a carrier tape formed from a sheet in which carbon black is dispersed in ABS resin or polystyrene resin has been used. This carrier tape has a good antistatic effect, but has insufficient mechanical strength. Furthermore, there is a drawback that deformation, bending, breakage and the like are likely to occur.
In addition, similar mechanical strength is required for a thin carrier tape in which conductive layers in which carbon black is dispersed in impact-resistant polystyrene resin are laminated on both surfaces of a base material layer of ABS resin or polystyrene resin. Yes.
In order to solve these problems, for example, Patent Document 1 discloses that carbon black is applied to one or both sides of a sheet base material made of a methyl methacrylate polymer or a polystyrene-based resin containing ethylene and a methyl methacrylate copolymer. A conductive composite plastic sheet laminated with a polystyrene-based resin has been proposed. However, a carrier tape formed from the sheet may be deformed during conveyance.

JP-A-10-329278

  The present invention provides a plastic sheet having an antistatic property and excellent mechanical strength by laminating a conductive layer on the surface of a base material layer made of a specific resin composition, and a pocket even if it is thin. It is an object of the present invention to provide a carrier tape that is not deformed or the like when packaging and storing electronic components housed in a package and mounting the circuit board on a circuit board.

In the present invention, a resin composition containing 1 to 20 parts by weight of AS resin and / or MS resin is used as a base layer with respect to 100 parts by weight of ABS resin, and a conductive layer is laminated on at least one side of the base layer. This is a plastic sheet for broadcasting electronic parts.
Furthermore, in the present invention, a resin composition containing 1 to 20 parts by weight of AS resin and / or MS resin is used as a base layer with respect to 100 parts by weight of ABS resin, and a conductive layer is laminated on at least one side of the base layer. A carrier tape formed from a plastic sheet.

The plastic sheet of the present invention is excellent in mechanical strength, impact resistance and molding processability. Even if it is thinned, the carrier tape, which is a molded product, has high rigidity and protects ICs or electronic parts stored in the pockets. When mounting on a circuit board at a high speed, the carrier tape can be transported at a high speed without being deformed.
In addition, there are few whiskers and burrs in the hole punching process, no cutting and cracking, no cracks in the seal in thermoforming of the carrier tape, uniform pocket thickness, and the corners are neat. A molded carrier tape can be formed.

Hereinafter, the present invention will be described in more detail.
The base material layer of the plastic sheet of this invention consists of a resin composition which contains 1-20 weight part of AS resin and / or MS resin with respect to 100 weight part of ABS resin.
The ABS resin is a resin mainly composed of a copolymer mainly composed of three components of acrylonitrile-butadiene-styrene.
The AS resin refers to a resin mainly composed of a copolymer mainly composed of two components of acrylonitrile-styrene. The MS resin is a resin mainly composed of a copolymer mainly composed of two components of methacrylate-styrene.
When AS resin and / or MS resin is less than 1 part by weight with respect to 100 parts by weight of ABS resin, a plastic sheet having high mechanical strength cannot be obtained, and the carrier tape formed from the thinned sheet is deformed. , Bending, breaking, etc. are likely to occur.
When AS resin and / or MS resin exceeds 20 parts by weight with respect to 100 parts by weight of ABS resin, a plastic sheet having high impact resistance cannot be obtained, and whiskers and burrs are generated during slitting and hole punching. Yes, cracks and the like are likely to occur. In addition, the carrier tape formed from the sheet is likely to be broken or cracked during storage and transportation of the stored IC or electronic component.

As the carbon black added to the conductive composition serving as the conductive layer on the surface, acetylene black, furnace black, ketjen black, or the like is preferably used. Moreover, the addition amount is 1 to 30 parts by weight, preferably 5 to 25 parts by weight with respect to 100 parts by weight of the resin used for the surface conductive layer. If the amount of carbon black added is less than 1 part by weight, the surface resistance of the surface conductive layer increases, so that the performance as an IC product packaging container is impaired. The extruding process of the adhesive composition becomes difficult and the mechanical strength is lowered. The surface resistance value of the plastic sheet is preferably 10 ³ to 10 ¹⁰ Ω.

As the resin used for the conductive layer, ABS resin, polystyrene resin, etc. are preferable, and the polystyrene resin has no significant decrease in fluidity even when a large amount of carbon black is added compared to other resins. It has advantages such as excellent properties.
Plastic sheets usually have physical properties such as mechanical strength, impact resistance, and bending strength in the base material layer that occupies most of the thickness, and the physical properties required of the base material layer in the conductive layer. There are cases where it is not necessary to be so strongly demanded.
For the resin composition and conductive composition of the present invention, a lubricant, a plasticizer, a processing aid, a reinforcing aid, etc., in order to improve the flow properties of the composition and the mechanical properties of the molded product as necessary. These various additives and other resin components can be added.

  In the present invention, the resin composition to be the base material layer can be used for containers of electronic parts, for example, magazines, trays, and the like by known methods such as pressure forming, vacuum forming, extrusion forming, injection molding and the like. .

The plastic sheet can be obtained by forming the raw material to be the base layer and the conductive layer into a sheet or film shape by an extruder or the like and then laminating by a heat laminating method, dry laminating method, extrusion laminating method, etc. It is also possible to obtain by integral molding by a known coextrusion method such as a feed block method or a multi-manifold method.
A conductive layer can also be obtained by applying a conductive paint on at least one side of the obtained base material layer. There is no restriction | limiting in particular as a resin part, For example, a general thing, for example, a polyurethane, an acrylic resin, etc. are used.

When used for a carrier tape, the thickness of the base layer of the plastic sheet can be appropriately changed according to the size and weight of the electronic component to be loaded, but is generally 0.1 to 0.5 mm. If it is less than 0.1 mm, the mechanical strength such as rigidity as a carrier tape obtained by molding the sheet is insufficient, and if it exceeds 0.5 mm, the mechanical strength is excessive and not economical, and it is difficult to form by thermoforming. It may become.
The thickness of the conductive layer is preferably 3 to 50 μm. If the thickness exceeds 50 μm, the corresponding effect cannot be improved, and it is not economical, and if it is less than 3 μm, a sufficient antistatic effect cannot be obtained.

  Carrier tape is usually formed by punching a feed hole for transporting a plastic sheet and heating a radiation heater, hot air, or hot plate to heat a pocket of a predetermined shape and size, vacuum forming, pressure forming, vacuum -After pressure forming or press forming, it is manufactured by slitting into a predetermined tape shape having a width of 8 to 56 mm.

After the electronic component is stored in the pocket, the carrier tape sealed and sealed with a cover tape as a lid is stored in a state of being wound around a reel.
When mounting electronic components on a circuit board, for example, a reel on which a carrier tape is wound is installed on a tape feeder of a mounting machine, and a transport claw of a sprocket member of the tape feeder is engaged with a feed hole of a carrier tape to By intermittently rotating the member, the cover tape is peeled off while the carrier tape is sequentially fed out. Then, the electronic component is sucked and picked up by the transfer head of the tape feeder, placed on the circuit board, and mounted.
When transporting the carrier tape, particularly when the thickness of the carrier tape is thin, the carrier tape is not extruded straight, and is likely to be deformed, bent, broken or the like.

  The configuration of the present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

Example 1
100 parts by weight of ABS resin (trade name “ET-70”, manufactured by Nippon A & L Co., Ltd.) and 10 parts by weight of AS resin (trade name “200PC”, manufactured by Nippon A & L Co., Ltd.), which are raw materials for the base material layer, and 100 parts by weight of polystyrene resin (trade name “H430”, manufactured by Nippon Polystyrene Co., Ltd.), which is a raw material for the conductive layer, and 20 parts by weight of carbon black were coextruded by a feed block method using a T-die, and the thickness was adjusted to 0. A conductive layer having a thickness of 25 μm was laminated on both surfaces of a 20 mm base material layer to obtain a thinned sheet having a total thickness of 0.25 mm and a width of 640 mm.

  The obtained sheet was heated with hot air at a temperature of 400 ° C. and vacuum-formed. The width was 16 mm, the pocket shape was 7.4 × 7.4 mm, the depth was 1.2 mm, the pocket pitch was 12 mm, and the feed hole diameter. A carrier tape having a thickness of 1.5 mm and a pitch of 4 mm was formed.

There were no cracks or cuts during sheet punching and slitting. In addition, there were few whiskers and burrs on the slit and punched surfaces.
The sheet had a flexural modulus of 2200 MPa (measurement method according to ISO 178) and a surface resistance value of 2 × 10 ⁵ Ω (measurement method according to JIS K6991).
The thickness of the pockets vacuum-formed on the carrier tape is uniform, the corners of the pocket are properly formed, and there is no cracking of the tape when forming the tape. Met.
When the carrier tape was wound around the reel, no deformation, bending, breakage, etc. were observed.

Comparative Example 1
A sheet having the same width and thickness and a carrier tape having the same shape and dimensions were obtained in the same manner as in Example 1 except that the AS resin was not used as the base material.
The sheet had a flexural modulus of 1860 MPa (measurement method according to ISO 178) and a surface resistance value of 2 × 10 ⁵ Ω (measurement method according to JIS K6991).
The thickness of the pockets vacuum-formed on the carrier tape is uniform, the corners of the pocket are properly formed, and there is no cracking of the tape when forming the tape. Met.
However, deformation occurred when the carrier tape was wound around the reel under the same conditions as in Example 1.

  Since the plastic sheet of the present invention has antistatic properties and is excellent in mechanical strength, impact resistance, and molding processability, a thin carrier tape molded from this plastic sheet is deformed, bent, broken, etc. The accident never happens. This carrier tape is reduced in cost, can store, store and transport electronic components, and can be used when mounted on a circuit board.

Claims (2)

  An electron comprising: a resin composition containing 1 to 20 parts by weight of an AS resin and / or MS resin with respect to 100 parts by weight of an ABS resin as a base material layer, and a conductive layer laminated on at least one surface of the base material layer. Plastic sheet for parts packaging.   Molded from a plastic sheet in which a resin composition containing 1 to 20 parts by weight of AS resin and / or MS resin is used as a base layer with respect to 100 parts by weight of ABS resin, and a conductive layer is laminated on at least one side of the base layer. Carrier tape characterized by that.