Blast and ballistic improvement in helmets
View Patent ↗A composite article having blast and ballistic resistance suitable for helmets, personal protection and hard armor applications comprises a high-strain hardening elastomeric layer and a layer of continuous yarns having a tenacity of 15 grams per dtex and a modulus of at least 500 grams per dtex or an oriented polyethylene sheet layer having a modulus ten times greater in one direction than in another direction.
1. A composite article having improved blast resistance and ballistic resistance comprising
(i) a first explosion resistant component facing a blast or ballistic source comprising a strain rate hardening elastomeric layer having a Young's modulus of from 7000 to 20000 psi at 100% strain and a strain-rate-sensitivity hardening in the strain rate range of approximately 1000/second to 1,000,000/second in association with a ballistic and/or explosive event, and
(ii) a second ballistic-resistant component facing an article to be protected comprising at least one layer comprising continuous filament yarns impregnated or coated with resin or a non-filamentary oriented polyethylene layer and the second ballistic-resistant component is a helmet shell,
wherein
the continuous filament yarns have a tenacity of at least 15 grams per dtex and a modulus of at least 500 grams per dtex and the oriented polyethylene layer has a modulus in a first direction that is at least ten times greater than the modulus in a second direction.
2. The composite article of claim 1 , comprising an optional third component positioned between the first and second components, the third component comprising at least one layer of continuous filament yarns or at least one layer of a non-filamentary oriented polyethylene layer.
3. The composite article of claim 1 , comprising an optional fourth component positioned between the second component and the article to be protected, the fourth component comprising at least one layer of continuous filament yarns or at least one layer of a non-filamentary oriented polyethylene sheet.
4. The composite article of claim 1 , wherein one or more of the layers of the second component comprises a woven fabric.
5. The composite article of claim 1 , wherein one or more of the layers the second component comprises a non-woven fabric.
6. The composite article of claim 1 , wherein the continuous filament yarns of the second component comprise polymeric filaments wherein the polymer is p-aramid, ultra-high molecular weight polyethylene, ultra-high molecular weight polypropylene, polyvinyl alcohol, polyazole or combinations thereof.
7. The composite article of claim 1 , wherein the elastomeric layer of the first component further comprises particles having a diameter of from 0.002 to 0.04 inches.
8. The composite article of claim 1 , wherein the elastomeric layer is configured into ridges.
9. The composite article of claim 1 , wherein the elastomer comprises polyurethane, polyurea, or a mixture thereof.
10. The composite article of claim 6 wherein the nonwoven fabric is a felt, a randomly oriented fibrous matt or a unidirectional fabric.
11. A panel comprising the composite article of claim 1 .
12. A helmet comprising the composite article of claim 1 .