Plastic and nonmetallic article shaping or treating: processes – Direct application of electrical or wave energy to heat the... – Electrical heating
Patent
1993-10-20
1997-01-21
Ortiz, Angela
Plastic and nonmetallic article shaping or treating: processes
Direct application of electrical or wave energy to heat the...
Electrical heating
264 291, 264299, 264301, 264319, 425169, 425269, 425275, B29C 4114, B29C 4140
Patent
active
055957048
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a shaping mold for production of ultra-thin shaped rubber articles, for example, condoms as a contraceptive device, medical rubber gloves to be used in the field of medical treatment such as surgical rubber gloves, and working rubber gloves to be used in the working filed of high-technology industry or the like so as to create a clean working environment therein and also to accurately carry out fine works therein, and it also relates to a method for producing such ultra-thin shaped rubber articles by the use of the shaping molds.
BACKGROUND ART
Ultra-thin shaped rubber articles such as condoms and others are generally produced by a process of using shaping molds made of glass or porcelain, a number of which shaping molds are mounted on an endless belt at determined intervals. The process comprises many steps of a washing step of washing the shaping molds with water in a washing tank, a dipping step of dipping the shaping molds successively in a latex liquid so as to make the latex adhere to the surfaces of the shaping molds, a heat-drying step of heating and drying the latex as adhered to the surfaces of the shaping molds for curing it thereon, and an inspecting step of dipping the shaped articles as shaped with the shaping molds in an electrolytic solution for effecting pin hole inspection of the articles by applying an electric current to the solution.
However, in accordance with the conventional process, the shaped article as adhered to the surface of the shaping mold is released from the surface after the heat-drying step. The released article is then mounted on an electroconductive inspecting mold for its pin hole inspection, and it must be dipped into an electrolytic solution as it is on the mold while applying an electric current to the solution for the inspection. Since the shaped article is an ultra-thin rubber article, the operation of peeling the shaped article from the shaping mold and of re-mounting the article to the inspecting mold in the inspecting step is extremely troublesome. Therefore, the inspecting step has been a stage of seriously retarding the process of producing ultra-thin shaped articles such as condoms and others.
In order to overcome the problem, a process has been proposed in which the shaping mold is made of a metal material and the shaped article, as heat-dried and adhered to the surface of the shaping mold, is directly dipped into the electrolytic solution in the inspecting step for effecting the pin hole inspection (Japanese Patent Publication No. 47-17,474). However, since the process uses a shaping mold made of a metal material, metal ions go into the latex from the shaping mold so that the condition of the colloid sol containing rubber as a dispersion medium is thereby worsened and good adhesion of the latex to the surface of the shaping mold becomes impossible, with the result that the process produces many defective articles. Because of this reason, the process has not been put to practical use.
We the present inventors have proposed, in order to overcome the above-mentioned problem, a shaping mold for producing ultra-thin shaped rubber articles, which shaping mold is made of an electroconductive ceramic material of SiC or ZrB.sub.2 or a mixture of them so that it may directly be used also as an inspecting mold as it is, whereby the troublesome operation of "peeling the shaped article from the shaping mold followed by remounting the article to a different inspecting mold" may be omitted (Japanese Patent Application Laid-Open No. 1-108,012). Using the shaping mold made of an electroconductive ceramic material, the problem that metal ions go into the latex in the dipping step may be overcome and production of ultra-thin shaped rubber articles may be effected continuously from the washing step to the successive dipping step, heat-drying step and inspecting step in order. The use of the shaping mold therefore yields a benefit of improving the production efficiency.
However, where the shaping mold is made of an electroc
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Hayashi Tomoyuki
Miyashita Kinya
Tatsumi Yoshiaki
Nisshinbo Industries Inc.
Ortiz Angela
Sohzohkagaku Co., Ltd.
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