Stock material or miscellaneous articles – Composite – Of polyamidoester
Reexamination Certificate
1997-09-30
2001-04-17
Pezzuto, Helen L. (Department: 1713)
Stock material or miscellaneous articles
Composite
Of polyamidoester
C428S458000, C428S461000, C428S480000, C428S483000, C428S500000
Reexamination Certificate
active
06218017
ABSTRACT:
TECHNICAL FIELD
The present invention relates to laminated structures, covering structures formed by processing the laminated structures, and pouches formed by processing the laminated structures. More particularly, the present invention relates to antistatic laminated structures, covering structures, and pouches for use as synthetic resin containers for containing semiconductor devices, IC devices, apparatus employing those devices, liquid crystal display parts, liquid crystal devices, medical articles including syringes and medical supplies, automotive parts and the like.
BACKGROUND ART
Various parts, solid or liquid foods have been contained in synthetic resin containers and sealed therein with covers closing the openings of the synthetic resin containers, and sealed in pouches for distribution and storage.
For example, there has been used an embossed carrier tape provided with a plurality of blisters formed by embossing, and sealing electronic parts in the blisters by heat-sealing a cover tape to the carrier tape so as to cover the blisters. Generally, a carrier tape for forming such an embossed carrier tape is formed of a material easy to mold in a sheet, such as a polyvinyl chloride, a polystyrene, a polyester, a polycarbonate or the like. The cover tape is a multilayer tape consisting of a biaxially oriented film and a heat sealant layer formed on one of the surfaces of the biaxially oriented film. The cover tape must be peeled from the carrier tape to take out electronic parts from the blisters of the embossed carrier tape when using the electronic parts in an electronic part mounting process.
There is a possibility that the electronic parts are deteriorated or damaged by static electricity generated by friction between the electronic parts contained in the embossed carrier tape, and the blisters or the cover tape, and static electricity generated when peeling off the cover tape. Therefore, the carrier tape and the cover tape needs means for preventing the electronic parts being deteriorated or damaged.
Conductive carbon particles, conductive powder of a metal oxide or the like or metal particles are dispersed in the carrier tape or the carrier tape is coated with such a conductive material as a means for preventing the generation of static electricity in the carrier tape. The heat sealant layer, which comes into direct contact with the electronic parts, is formed of a material containing an antistatic agent, such as a surface active agent, conductive powder of a metal oxide, conductive carbon particles or metal particles, or the heat sealant layer is coated with such a conductive material. A material containing a fine powder of conductive metal oxide, such as tin oxide or zinc oxide, is relatively transparent and is often used for forming the heat sealant layer.
However, the cover tape must be bonded to the carrier tape by heat-sealing with a predetermined bonding strength in order to prevent the separation of the cover tape from the embossed carrier tape during transportation and storage, and the resultant falling off of the electronic parts from the embossed carrier tape. If the heat-bonding strength is excessively high and the range of variation of the heat-bonding strength (the difference between a maximum and a minimum adhesive strength of the cover tape and the carrier tape, which will be referred to as “zip-up”) is excessively wide, the carrier tape vibrates and ejects the electronic parts from the blisters of the carrier tape in an electronic part mounting process. Accordingly, it is desired that the cover tape is bonded to the carrier tape with a sufficient adhesive strength and the zip-up in the adhesive strength is small when taking out the electronic parts from the blisters. However, the zip-up of a conventional cover tape provided with a heat sealant layer containing conductive particles or the like cannot be reduced.
Although a cover tape provided with a heat sealant layer containing conductive powder of metal oxide has a relatively high degree of transparency, it is difficult to disperse the conductive powder when forming the heat sealant layer, and an advanced dispersing technique is required for forming the heat sealant layer in a transparency that enables the visual inspection of the electronic parts, which increases manufacturing costs.
If a surface active agent is applied to the cover tape, the surface condition of the heat sealant layer changes, and the sealing performance of the heat sealant layer becomes unstable causing faulty sealing. Since the static eliminating effect is greatly dependent on the temperature and the moisture of the storage environment, stable antistatic effect cannot be expected.
DISCLOSURE OF THE INVENTION
The present invention has been made in view of those problems and it is therefore an object of the present invention to provide a laminated structure having an excellent antistatic characteristic, a cover tape having excellent properties to be attached to and peeled from a synthetic resin container and excellent electrostatic characteristics, and a pouch having a high adhesive property and excellent electrostatic characteristics.
With the foregoing object in view, according to a first aspect of the present invention, a laminated structure comprises a heat sealant layer, and an antistatic layer formed on one surface of the heat sealant layer. The antistatic layer contains, as a principal component, a bisammonium organic sulfur semiconductor.
A covering structure in accordance with the present invention is formed by processing a laminated structure obtained by forming oriented resin layers on the surface of the heat sealant layer provided with the antistatic layer of the foregoing laminated structure, and the other surface of the heat sealant layer of the same laminated structure, respectively. The surface of the heat sealant layer provided with the antistatic layer is bonded to a synthetic resin container by heat-sealing.
A pouch in accordance with the present invention is formed by processing the laminated structure obtained by forming oriented resin layers on the surface of the heat sealant layer provided with the antistatic layer of the foregoing laminated structure, and the other surface of the heat sealant layer of the same laminated structure, respectively. The surface of the heat sealant layer provided with the antistatic layer forms the inner surface of the pouch.
The antistatic layer formed on one surface of the heat sealant layer of the laminated structure is formed of a material containing a bisammonium organic sulfur semiconductor as a principal component. Since the bisammonium organic sulfur semiconductor has a satisfactory antistatic property and the antistatic effect of the bisammonium organic sulfur semiconductor is independent of humidity, the laminated structure has an antistatic characteristic. Since the bisammonium organic sulfur semiconductor is transparent and colorless, and does not affect the heat-sealing property of the heat sealant layer, the covering structure formed by processing the laminated structure obtained by forming oriented resin layers on the surface of the heat sealant layer provided with the antistatic layer of the foregoing laminated structure, and the other surface of the heat sealant layer of the same laminated structure, respectively, has excellent electrostatic characteristics and good ability to make the contents visible. When the surface of the heat sealant layer provided with the antistatic layer of the covering structure is bonded to a synthetic resin container by heat-sealing, the oriented resin layer and the heat sealant layer can be separated from each other or the heat sealant layer is subject to cohesive failure. Therefore, the covering structure can stably and surely be peeled off regardless of heat-sealing strength. The pouch formed by processing the laminated structure obtained by forming the oriented resin layers on the surface of the heat sealant layer provided with the antistatic layer of the foregoing laminated structure, and the other surface of the heat sealant
Matsuzaki Hiroshi
Yamashita Rikiya
Yamazaki Takuya
Dai Nippon Printing Co. Ltd.
Pezzuto Helen L.
LandOfFree
Laminated structure, covering structure and pouch does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Laminated structure, covering structure and pouch, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Laminated structure, covering structure and pouch will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2534730