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US 10,441,471 B2Granted
Push-in earplug
Assignee3M Innovative Properties Company
InventorsJames P. Endle, Jeffrey L. Hamer, Alan R. Seville, Kenneth F. Teeters
Life of this patent
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Abstract
A push-in earplug including an elongate core and outer layer is disclosed. The outer layer includes a sound attenuating portion having a first average density and a stem portion having a second average density, and the second average density is greater than the first average density.
Claims5
A method for forming an earplug having a stem portion and a sound attenuating portion, comprising:
- providing a preform comprising (i) an elongate core comprising a first material and having first and second ends and an outer major surface;
- and (ii) an outer layer comprising a second material and covering at least a portion of the outer major surface of the elongate core, wherein the second material comprises expandable spheres including thermoplastic shells encapsulating a gas;
- and
- expanding the spheres to expand the second material, wherein the second material in proximity to the first end of the elongate core is expanded to a greater extent than the second material in proximity to the second end of the elongate core,
- wherein the expanded second material in proximity to the first end of the elongate core forms the sound attenuating portion of the earplug and wherein the second material in proximity to the second end of the elongate core forms the stem portion of the earplug.
2 more elements
Dependencies are inferred from the claim text.