Coating suitable for surgical instruments

Abstract

A coating and devices using the coating are provided. The coating is applied in liquid form and dried or otherwise cured to form a durable adherent coating resistant to high temperatures and having optional hydrophobic properties. The coating formulation contains an aqueous formulation of silica, one or more fillers, and sufficient base, (e.g., potassium hydroxide), to have a pH exceeding about 10.5 during at least part of the formulation process. The formulation may contain a compound(s) that affects surface free energy, energy to make the cured coating hydrophobic. Such compounds include silanes containing halogens (e.g., fluorine or chlorine) and in particular silanes containing one or more hydrolyzable groups attached to at least one silicon atom and a group containing one or more halogens (e.g., chlorine or fluorine). A medical instrument (e.g., electrosurgical instrument) may be at least partially covered by a coating using the formulation.

1 . A surgical instrument for receiving electrosurgical energy, wherein at least part of said instrument is insulated with a coating having a substantially non-stick coating formulation comprising:
 silica;   at least one inorganic filler; and   a base in an amount so that the coating formulation has a pH of at least 10.5 during at least part of a formulation process, wherein said base comprises potassium hydroxide.   
     
     
         2 . The surgical instrument of  claim 1 , wherein the instrument is a blade. 
     
     
         3 . The surgical instrument of  claim 2  in which the coating is between about 0.001 and 0.1 inches thick. 
     
     
         4 . The surgical instrument of  claim 3  in which the coating is between about 0.002 and 0.010 inches thick. 
     
     
         5 . The surgical instrument of  claim 2  in which a portion of the blade has an impedance of less than about 5,000 ohms comprised of an edge exposed through the insulation. 
     
     
         6 . The surgical instrument of  claim 2  wherein at least a portion of said blade is composed of stainless steel. 
     
     
         7 . The surgical instrument of  claim 1  in which the instrument has at least a portion with an impedance less than about 5,000 ohms. 
     
     
         8 . The surgical instrument of  claim 1 , the coating formulation further comprising:
 at least one alkoxy silane.   
     
     
         9 . The surgical instrument of  claim 8 , wherein said at least one alkoxy silane of the formulation comprises at least one alkylalkoxysilane. 
     
     
         10 . The surgical instrument of  claim 9 , wherein said at least one alkylalkoxy silane of the formulation includes at least one halogen being at least one of:
 chlorine and   fluorine.   
     
     
         11 . The surgical instrument of  claim 10 , wherein said at least one alkylalkoxysilane of the coating formulation is selected from a group consisting of:
 fluoroalkylalkoxysilanes; and   chloroalkylalkoxysilanes.   
     
     
         12 . The surgical instrument of  claim 1 , wherein the coating formulation further comprises at least one of the following:
 a material including a fluorinated carbon chain; and   a material including at least partially hydrolyzed fluorinated silanes; and   a material including at least partially cross-linked hydrolyzed silanes.   
     
     
         13 . The surgical instrument of  claim 11 , wherein said at least one alkylalkoxysilane of the coating formulation comprises at least one hydrolyzable inorganic alkylsilyl group. 
     
     
         14 . The surgical instrument of  claim 13 , wherein said hydrolyzable inorganic alkylsilyl of the coating formulation group is selected from a group consisting of:
 a methoxysilyl group; and   an ethoxysilyl group.   
     
     
         15 . The surgical instrument of  claim 1 , wherein said coating formulation comprises at least 10 weight percent of a solution comprising a colloidal silicate. 
     
     
         16 . The surgical instrument of  claim 15 , wherein said solution of the coating formulation comprises an alkali metal silicate solution. 
     
     
         17 . The surgical instrument of  claim 1 , wherein said coating formulation comprises at least 10 weight percent of a solution comprising a colloidal silicate. 
     
     
         18 . A process of manufacturing a surgical instrument in which a stainless steel blade is coated at least in part with a material that produces a substantially non-stick coating, comprising:
 preparing a coating formulation comprising:
 silica; 
 at least one inorganic filler; 
 at least one hydrolyzable inorganic alkylsilyl; and 
 a base in an amount so that the coating formulation has a pH of at least 10.5 during at least part of the preparing step, wherein said base comprises potassium hydroxide; 
   applying the coating to at least a portion of a stainless steel blade of a surgical instrument;   drying the coated portion of the stainless steel blade at about 60 to 200 degrees Fahrenheit;   curing the coated portion of the stainless steel blade at a temperature greater than about 350 degrees Fahrenheit.   
     
     
         19 . The process  claim 18 , wherein said at least one hydrolyzable inorganic alkylsilyl contains at least one halogen. 
     
     
         20 . The process  claim 18 , wherein said at least one halogen is comprised of at least one of:
 chlorine; and   fluorine.