Stock material or miscellaneous articles – Hollow or container type article – Polymer or resin containing
Patent
1995-06-26
1997-11-11
Nold, Charles
Stock material or miscellaneous articles
Hollow or container type article
Polymer or resin containing
428 357, 206531, 220507, B65D 8304
Patent
active
056861567
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a press-through package and more particularly it relates to a press-through package excellent in water vapor barrier properties.
BACKGROUND ART
A synthetic resin sheet as a base material for a press-through package (hereinafter referred to as PTP) is preferably so transparent that packed objects are clearly visible in the pocket portions of the sheet. Furthermore, for preventing the change in properties of the packed objects caused by moisture, it is preferable that the sheet has a low water vapor transmission rate. Sheets made of a poly(vinyl chloride) or a polypropylene have been used. In addition, laminated sheets of a polypropylene and a poly(vinylidene fluoride) have been used in PTP's which are particularly required to have water vapor barrier properties.
Poly(vinyl chloride)s, however, have been disadvantageous in that they do not have a water vapor transmission rate sufficiently low to pack a drug easily changeable in properties by moisture and are difficult to incinerate after use. On the other hand, polypropylenes have been disadvantageous as follows: they are not good in vacuum forming properties, so that when the openings of pockets are formed in a sheet by vacuum forming, the thickness of the pocket portions tends to become nonuniform; and molded sheets of the polypropylenes are liable to be curled and hence are poor in workability. The laminated sheets of a polypropylene and a poly(vinylidene fluoride) have been disadvantageous in not only being unsatisfactory in vacuum forming properties, workability, etc. but also being difficult to incinerate.
DISCLOSURE OF THE INVENTION
The present inventors found that when a sheet made of a thermoplastic norbornene type resin is used as a synthetic resin sheet used as a base material for PTP, it has a low water vapor transmission rate, is easy to incinerate, and can give pockets uniform in their thickness in the formation of the openings of the pockets by vacuum forming, whereby the present invention has been accomplished.
Thus, according to present invention, there is provided a PTP obtained by placing objects to be packed, in accommodating pockets formed in a sheet made of a thermoplastic norbornene type resin, and then closing the openings of pockets of the sheet with another sheet to pack the objects to be packed.
BEST MODE FOR CARRYING OUT THE INVENTION
(Thermoplastic Norbornene Type Resin)
The thermoplastic norbornene type resin used in the present invention is a resin well known in Japanese Patent Unexamined Publication Nos. 51-80400, 60-26024, 1-168725, 1-190726, 3-14882, 3-122137 and 4-63807, etc. Specific examples of the thermoplastic norbornene type resin are ring-opening polymerization products of norbornene type monomers, hydrogenated products thereof, addition polymers of norbornene type monomers, and addition polymers of a norbornene type monomer and an olefin.
The norbornene type monomers are monomers also well known in the above references, Japanese Patent Unexamined Publication Nos. 2-227424 and 2-276842, etc. and include, for example, norbornene, alkyl-, alkylidene- or aromatic-substituted derivatives of norbornene, and substituted products of these substituted or unsubstituted olefins, which have as the substituent(s) one or more polar groups selected from halogens, hydroxyl group, ester groups, alkoxy groups, cyano group, amide group, imide group, silyl group, etc., for instance, 2-norbornene, 5-methyl-2-norbornene, 5,5-dimethyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene, 5-ethylidene-2-norbornene, 5-methoxycarbonyl-2-norbornene, 5-cyano-2-norbornene, 5-methyl-5-methoxycarbonyl-2-norbornene, 5-phenyl-2-norbornene, 5-phenyl-5-methyl-2-norbornene, 5-hexyl-2-norbornene, 5-octyl-2-norbornene and 5-octadecyl 2-norbornene; monomers formed by addition of one or more molecules of cyclopentadiene to norbornene, and the same derivatives and substituted products as above of these monomers, for instance, 1,4:5,8-dimethano-1,2,3,4,4a,5,8,8a-2,3-cyclopentadienooctahydro-na
REFERENCES:
patent: 5360116 (1994-11-01), Schmiletzky
Hani Tsutomu
Kohara Teiji
Matsui Toshiyasu
Natsuume Tadao
Nippon Zeon Co. Ltd.
Nold Charles
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