Ion implantation of silicone rubber

• US 5,223,309 A
• Filed: 07/08/1992
• Issued: 06/29/1993
• Est. Priority Date: 07/10/1991
• Status: Expired due to Term

• Current Assignee: Spire Corporation
• Original Assignee: Spire Corporation
• Inventors: Farivar, Robert S., Sioshansi, Piran
• Primary Examiner(s): PIANALTO, BERNARD D
• Application Number:
  US07/910,777
• Time in Patent Office: 356 Days
• Field of Search: 427/38, 427/296, 427/525, 427/527
• US Class Current: 427/525
• CPC Class Codes: A61L 33/0094 Physical treatment, e.g. plasma treatment
• CPC Class Codes: B29C 2035/0872 using ion-radiation, e.g. alpha-rays
• CPC Class Codes: B29C 59/16 by wave energy or particle radiation , e.g. infrared heating B29C59/007 takes precedence
• CPC Class Codes: B29K 2083/00 Use of polymers having silicon, with or without sulfur, nitrogen, oxygen, or carbon only, in the main chain, as moulding material
• CPC Class Codes: C08J 2383/04 Polysiloxanes
• CPC Class Codes: C08J 7/123 Treatment by wave energy or particle radiation C08J7/18 takes precedence

Abstract

A process to improve the surface properties of products made, at least in part, from silicone rubber is disclosed. The products find uses in industrial and medical device applications, such as drug-pump seals and valves, membranes, mammary prostheses, artificial heart diaphragms, pacemaker lead insulation and the like. The process is designed to change the silicone rubber'"'"'s surface to one that is characterized by low friction, being antithrombotic, inkable, more wear resistant and deformable, and also being hydro-compatible. The process includes subjecting the product'"'"'s silicone rubber surface to ion bombardment with gaseous ions that diffuse out with doses and at energy levels at least about 3E14 ions/cm² at 80 keV.

Claims

1. A process of improving the surface properties of silicone rubber products by reducing their surface roughness comprising:

(a) providing a product at least in part from silicone rubber;

(b) subjecting said product to ion bombardment with a gaseous ion so as to reduce said product'"'"'s surface roughness and its coefficient of friction;

(c) said ion bombardment being effected with a dose of at least about 3E14 ions/cm² at a particle energy of about 80 keV;

(d) sad gaseous ion being one of a group consisting of nitrogen, helium, hydrogen, argon, oxygen, neon, flourine, krypton, xenon, CF₄ CH₄ and CO₂ ;

(e) said ion bombardment effecting a lasting change in the surface energy of said ion bombarded surface.

2. The process of claim 1 wherein said product is one or more of the group including:

drug-pump seals, drug-pump valves, membranes, electro-stimulation devices, pacemaker lead insulation, artificial heart diaphragms, catheters, mammary prostheses, penile implants, vascular grafts and finger joints and assorted medical tubing.

3. The process of claim 1 wherein said dose ranges from about said 3E14 ions/cm² to about 3E17 ions/cm², wherein said reduced coefficient of friction approximates that of latex rubber, wherein said ion bombardment is effected with a current density from about 0.01 uA/cm² to abut 10.00 uA/cm², wherein said reduced coefficient of friction helps to reduce fibrin adsorption on said product'"'"'s surface, and wherein said gaseous ion is an isotopically pure ion specie of one of said group.

4. A process of effecting lasting changes in the surface morphology and surface energy of silicone rubber products comprising:

(a) providing a product made at least in part from silicone rubber;

(b) mounting said product in a chamber;

(c) creating a vacuum of at least about 10^-3 torr in said chamber;

(d) exposing the surface of said product to an ion beam of gaseous ions so as to reduce the surface roughness and the coefficient of friction of said surface, with said coefficient of friction approximating that of latex rubber;

(e) said ion beam having a dose varying from about 3E14 ions/cm² to about 3E17 ions/cm² at a particle energy ranging from about 0.5 keV to about 120 keV, and with a current density ranging from about 0.01 uA/cm² to about 10.000 uA/cm² ;

(f) said ion beam being composed of an isotopically pure ion specie;

(g) said exposing said surface of said product to said ion beam, being for a time period from about 5 minutes to about 10 hours.

5. The process of claim 4 wherein said product is one or more of the group including:

drug-pump seals, drug-pump valves, membranes, electro-stimulation devices, pacemaker lead insulation, artificial heart diaphragms, catheters, mammary prostheses, penile implants, vascular grafts and finger joints and assorted medical tubing.

6. The process of claim 4 wherein said gaseous ions being one of a group consisting of nitrogen, helium, hydrogen, argon, oxygen, neon, fluourine, krypton, xenon, CF₄, CH₄ and CO₂.

7. The process of claim 4 wherein said exposing the surface of said product to said ion beam effects a lasting increase in the surface energy of said surface rendering said surface to be more wear resistant, deformable, and hydro-compatible.