Vulcanization of dip-molded rubber articles with molten media baths
AssigneeApex Medical Technologies, Inc.
InventorsMark W. McGlothlin, Eric V. Schmid
Life of this patent
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Abstract
Pore-free rubber articles are prepared by dip-molding in a dipping medium that includes a vulcanizing agent, then by immersing the dip former in a heated liquid bath that is chemically inert. A particularly effective liquid bath is molten inorganic salt. In addition, the tensile properties of an article of vulcanized rubber can be improved to an unusually effective degree by immersing the already vulcanized article in a solution of a vulcanizing agent to cause the rubber of the article to absorb or imbibe the vulcanizing agent from the solution, and then immersing the rubber and the imbibed vulcanizing agent in a heated liquid bath to increase the degree of vulcanization.
Claims54
A method for the preparation of a substantially pore-free article of rubber other than cis-1,4-polyisoprene, said method comprising:
- (a) dipping a forming member in a liquid medium comprising
- (i) a rubber-forming substance other than cis-1,4-polyisoprene and
- (ii) a vulcanizing agent, said forming member having an outer surface with a contour complementary to that of said article;
- (b) withdrawing said forming member from said liquid medium in such a manner as to leave a film of said liquid medium over said outer surface;
- (c) immersing said forming member with said liquid film thereon in a chemically inert liquid bath at a temperature and for a period of time sufficient to cause vulcanization of said rubber-forming substance by said vulcanizing agent;
- and
- (d) withdrawing said forming member from said liquid bath and separating said substantially pore-free rubber article from said forming member.
A method for increasing the tensile strength of an article of vulcanized rubber, said method comprising:
- (a) immersing said article in a solution of a vulcanizing agent to cause said article to absorb said second vulcanizing agent from said solution;
- (b) immersing said article containing said absorbed vulcanizing agent in a chemically inert liquid bath at a temperature and for a period of time sufficient to cause further vulcanization said vulcanized rubber by said vulcanizing agent;
- and
- (c) withdrawing said article from said liquid bath.
A method for the preparation of a substantially pore-free article of rubber, said method comprising:
- (a) dipping a forming member in a liquid medium comprising
- (i) a rubber-forming substance and
- (ii) a first vulcanizing agent, said forming member having an outer surface with a contour complementary to that of said article;
- (b) withdrawing said forming member from said liquid medium in such a manner as to leave a film of said liquid medium over said outer surface;
- (c) immersing said forming member with said liquid film thereon in a first chemically inert liquid bath at a temperature and for a period of time sufficient to cause vulcanization of said rubber-forming substance by said first vulcanizing agent;
- (d) withdrawing said forming member with a film of vulcanized rubber thereon from said liquid bath;
- (e) immersing said film of vulcanized rubber formed in step (d) in a solution of a second vulcanizing agent to cause said film to absorb said second vulcanizing agent from said solution;
- (f) immersing said film containing said absorbed second vulcanizing agent in a second chemically inert liquid bath at a temperature and for a period of time sufficient to cause further vulcanization of said rubber-forming substance by said second vulcanizing agent;
- and
- (g) withdrawing said film from said second liquid bath to achieve said substantially pore-free rubber article.
A dip-molded article of a rubber other than cis-1,4-polyisoprene that is substantially pore-free, formed by a process comprising:
- (a) dipping a forming member in a liquid medium comprising
- (i) a rubber-forming substance other than cis-1,4-polyisoprene and
- (ii) a vulcanizing agent, said forming member having an outer surface with a contour complementary to that of said article;
- (b) withdrawing said forming member from said liquid medium in such a manner as to leave a film of said liquid medium over said outer surface;
- (c) immersing said forming member with said liquid film thereon in a chemically inert liquid bath at a temperature and for a period of time sufficient to cause vulcanization of said rubber-forming substance by said vulcanizing agent;
- and
- (d) withdrawing said forming member from said liquid bath and separating said substantially pore-free article of rubber article from said forming member.
Dependencies are inferred from the claim text.