Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1997-05-29
1998-09-15
Morgan, Kriellion S.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
524119, 524378, 524390, 524391, 524384, 524464, 524500, 524540, 524611, G21F 110, C08K 549, C08K 506
Patent
active
058079084
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to an ionizing radiation-resistant polycarbonate resin composition and a medical part comprising the same. The present invention relates more in detail to a polycarbonate resin composition which exhibits no deterioration of color and physical properties even when it is irradiated with ionizing radiation for sterilization, and a medical part comprising such a composition.
CONVENTIONAL ART
A polycarbonate resin is excellent in mechanical and thermal properties, and used for wide applications. Moreover, since the polycarbonate resin has excellent transparency, sanitary properties, toughness and heat resistance, it is used, for example, for packaging parts having a container form for accommodating or packaging injectors, surgical tools, intravenous injectors, operation instruments, and the like, for parts of medical apparatuses such as artificial lungs, artificial kidneys, anesthetic inhalators, vein connectors and their accessaries and centrifugal separators for blood, and for medical parts for surgical tools and operation tools.
These medical parts are usually completely sterilized. Concretely, the sterilization is carried out by contacting them with ethylene oxide, heat treating them in an autoclave, or irradiating them with ionizing radiation such as .gamma.-rays and an electron beam.
Among these sterilization procedures, the contact treatment with ethylene oxide is not preferred because ethylene oxide itself is toxic and unstable, and involves environmental problems related to waste treatment. Moreover, the heat treatment of the parts in an autoclave has disadvantages that the resin may be deteriorated during the treatment at high temperature, that its energy cost is high, and that the parts are required to be dried after the treatment due to remaining moisture.
Accordingly, in place of these procedures, sterilization by irradiation of the parts with ionizing radiation which can be carried out at low temperature at relatively low cost is employed.
However, the polycarbonate resin which is inherently optically transparent turns yellow when irradiated with ionizing radiation. Therefore, methods such as a method of mixing a blue colorant with the resin and a method of adding various additives for inhibiting the yellowing have been proposed.
For example, the following methods are known: a method of incorporating a polyester or a copolyester such as a polyester comprising 1,4-cyclohexyldimethanol and a six-membered carbocyclic dicarboxylic acid disclosed in EP-A-152825 and EP-A-226189; a method of incorporating a mercapto compound such as a thioglycol disclosed in Japanese Patent Kokai Publication Nos. 49058/1990, 115260/1990 and 36343/1992; a method of adding a polyether polyol such as polypropylene glycol, or its alkyl ether disclosed in U.S. Pat. No. 4,904,710, EP-A-296473, EP-A-338319, U.S. Pat. No. 4,874,802, EP-A-359366, U.S. Pat. Nos. 4,804,692 and 4,873,271 and EP-A-439763; a method of adding an epoxide compound disclosed in EP-A-272421; a method of adding a boron compound disclosed in EP-A-189583; a method of adding a polyfunctional monomer containing at least two aliphatic double bonds within the molecule disclosed in Japanese Patent Kokai Publication No. 33115/1991; and a method of adding a halogenated compound represented by a polycarbonate or copolycarbonate derived from a halogenated bisphenol A disclosed in Japanese Patent Kokai Publication Nos. 55062/1990 and 68068/1990 and EP-A-376289. Even these methods cannot sufficiently inhibit the yellowing of polycarbonate resins when the resins are irradiated with ionizing radiation.
Furthermore, various methods in which the additives as mentioned above or the compounds having functional groups as mentioned above are added in combination are proposed.
Examples of such methods are a method of adding a halogenated bisphenol A type epoxy compound disclosed in Japanese Patent Kokai Publication No. 7356/1992; a method of adding a halogenated bisphenol A and a thioether disclosed in Japanese Patent Koka
Hirose Yoshikazu
Kawamoto Naoyoshi
Suzuki Shigeharu
Morgan Kriellion S.
Sumitomo Dow Limited
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