Earplugs

Abstract

There are disclosed earplugs composed of certain polymeric foam materials. The earplugs are of generally cylindrical shape and of somewhat larger diameter than the human ear canal. The earplugs are composed of a foamed plasticized polymeric material having a sufficiently high concentration of plasticizer to provide the earplug with a reduced rate of recovery from compression.

What is claimed is: 
     
       1. An earplug of generally cylindrical shape having a diameter of between 3/8 and 3/4 inch, a length .[.to.]. .Iadd.of .Iaddend.between 1/2 and 1 inch and composed of a resilient plasticised polymeric foam having a sufficiently high concentration of organic plasticizer therein as to provide said foam with a rate of recovery .[.of.]. .Iadd.from .Iaddend.60 percent compression thereof to 40 percent compression .Iadd.thereof .Iaddend.of from 1 to 60 seconds and an equilibrium pressure .[.of.]. .Iadd.at .Iaddend.40 percent compression thereof of from 0.2 to 1.3 p.s.i. 
     
     
       2. The earplug of claim 1 wherein said polymeric foam has a rate of recovery of from 2 to 20 seconds. 
     
     
       3. The earplug of claim 1 wherein said polymeric foam has an equilibrium pressure at 40 percent compression of between 0.35 and 1.0 p.s.i. 
     
     
       4. The earplug of claim 1 wherein the polymeric constituent of said foam is a polymer of vinyl chloride. 
     
     
       5. The earplug of claim 1 wherein the polymeric constituent of said foam is a homopolymer of vinyl chloride. 
     
     
       6. The earplug of claim 1 having a diameter of between 9/16 and 11/16 inch. 
     
     
       7. The earplug of claim 1 having a length of between 7/16 and 3/4 inch. 
     
     
       8. The earplug of claim 1 wherein said polymeric foam is formed from a polyvinylchloride plastisol. 
     
     
       9. The earplug of claim 1 having a truncated cone shape. 
     
     
       10. The earplug of claim 1 having a substantially longitudinal bore therethrough said bore being adapted to receive the tip portion of a sound conducting tube. .Iadd. 11. An earplug having a size and shape adapted to be compressed and inserted into the human ear canal and there allowed to expand and obturate the ear canal, said earplug comprising a resilient plasticized polymeric foam having a sufficiently high concentration of organic plasticizer therein as to provide said foam with a rate of recovery from 60 percent compression thereof to 40 percent compression thereof of from 1 to 60 seconds and an equilibrium pressure at 40 percent compression thereof of from 0.2 to 1.3 p.s.i. .Iaddend..Iadd. 12. An earplug as in claim 11 having a generally cylindrical shape. .Iaddend..Iadd. 13. An earplug as in claim 11 wherein said polymeric foam has a rate of recovery from 60 percent compression thereof to 40 percent compression thereof from 2 to 20 seconds. .Iaddend..Iadd. 14. An earplug as in claim 11 wherein said polymeric foam has an equilibrium pressure at 40 percent compression thereof from 0.35 to 1.0 p.s.i. .Iaddend..Iadd. 15. An earplug as in claim 11 wherein the polymeric constituent of said foam is a polymer of vinyl chloride. .Iaddend..Iadd. 16. An earplug as in claim 11 wherein said polymeric foam is formed from a polyvinylchloride plastisol. .Iaddend..Iadd. 17. An earplug as in claim 11 having a truncated conical shape. .Iaddend..Iadd. 18. An earplug as in claim 11 having a bore therethrough, said bore being adapted to receive a sound conducting tube. .Iaddend..Iadd. 19. An earplug as in claim 18, further comprising a sound conducting tube mounted in said bore. .Iaddend.