US20080026658A1 - Multi-axially stretchable polymer shock absorbing pad - Google Patents

Abstract

Disclosed is a multi-axial stretchable, viscoelastic, shock-attenuating elastomeric pad or fabric comprising a polymeric gel forming an inner core. The polymeric gel may be sandwiched between two opposed layers of multi-axial stretchable fabric having open ends or enclosed within an envelope having opposed layers of multi-axial stretchable fabric whereby impact can be absorbed and dissipated.

Description

CROSS-REFERENCE TO RELATED APPLICATION
• This application is a continuation-in-part of U.S. patent application Ser. No. 11/430,187 filed Apr. 8, 2006, which is a continuation-in-part U.S. patent application Ser. No. 10/681,831, filed Oct. 8, 2003, which is a continuation-in-part of U.S. Pat. No. 7,041,719, filed Sep. 26, 2003, which is a continuation-in-part of U.S. Pat. No. 6,896,064, filed Jul. 3, 2003, which is a continuation-in-part of U.S. Pat. No. 6,588,511, filed Mar. 7, 2002, the present application further relies upon U.S. Provisional Patent Application No. 60/821,604 filed Aug. 7, 2006 and U.S. Provisional Patent Application No. 60/821,587 also filed Aug. 7, 2006; the contents of which all the applications listed above are hereby incorporated in their entirety.
TECHNICAL FIELD
• The present invention generally relates to stretchable fabrics and in greater detail the invention relates to a multi-axial stretchable, viscoelastic, shock-attenuating elastomeric pad or fabric.
BACKGROUND
• Enhanced participation in contact sports, such as football, soccer, and rugby, along with enhanced participation in other high impact energy activities, such as inline skating and white water kayaking, has fueled the demand and need for improved impact absorbing materials. These types of contact sports and high-impact activities often cause application of high energy impacts against discrete portions of the human body that often cause bruises and even more serious injuries, such as broken or fractured bones.
DRAWINGS
• In the Drawings:
• FIG. 1 illustrates the multi-axially stretchable pad comprising a first and second layer of multi-axially stretchable fabric substantially surrounding a polymeric gel; and
• FIG. 2 depicts the multi-axially stretchable pad comprising a first and second layer of multi-axially stretchable fabric enveloping a polymeric gel.
DETAILED DESCRIPTION
• The present invention comprises a multi-axial stretchable, viscoelastic, shock-attenuating elastomeric pad or fabric comprising a polymeric gel forming an inner core. The polymeric gel may be sandwiched between two opposed layers of multi-axial stretchable fabric having open ends or enclosed within an envelope having opposed layers of multi-axial stretchable fabric whereby impact can be absorbed and dissipated.
• Opposed Layers
• The opposed multi-axial layers defining an envelope there between. The layers may be joined using mechanical means such as stitching, stapling or other fasteners. Adhesives may also be used to join the layers together, or a combination of any of the methods mentioned above or those known in the art may be used for joining the layers. Additionally, the ends may be open such that the opposed multi-axial layers sandwich the polymeric gel.
• The term multi-axial layer may include any fabric, woven or nonwoven, that may stretch about an axis in multiple directions. By way of example and not limitation, the fabric may stretch 360 degrees about an axis or have a 4 way stretchability.
• The multi-axial stretchable pad may be comprised of one or more envelopes residing in a single larger envelope. The two opposed layers may be joined at multiple points creating a plurality of envelopes encompassing the gel compound.
• Theopposed layers2 may be formed from a woven or a non-woven material capable of containing thegel4 and able to withstand rupturing upon impact. Furthermore, it is contemplated that the envelope may be comprised of more that two layers and that the envelope may be encased in a further envelope to add protection and durability to the overall envelope.
• Polymeric Gel
• The energy absorbing polymeric compound may be comprised of most any polymeric gel. The gel incorporated into the envelope is both viscoelastic and shock-attenuating.
• An example gel compound is one that comprises an epoxidized vegetable oil combined with a prepolymer and a thermoplastic polymer. Additionally, a catalyst or an accelerant may be added to the energy absorbing compound to aid in the formation of the compound. Typically the activator or accelerant is a metal activator such as an alkyl tin compound.
• The elastomeric compound includes an epoxidized vegetable oil which can function as a plasticizer. By way of example, the epoxidized vegetable oils can include epoxidized soybean oil, epoxidized linseed oil and epoxidized tall oil. Additional examples of epoxidized vegetable oils include epoxidized corn oil, epoxidized cottonseed oil, epoxidized perilla oil and epoxidized safflower oil. Epoxidized vegetable oils are typically obtained by the epoxidation of triglycerides of unsaturated fatty acid and are made by epoxidizing the reactive olefin groups of the naturally occurring triglyceride oils. Typically, the olefin groups are epoxidized using a peracid. One example of an acceptable epoxidized vegetable oil is an epoxidized soybean oil, Paraplex G-62, available from C.P. Hall Company of Chicago, Ill. Paraplex G-62 can function as both a plasticizer and a processing aid and is a high molecular weight epoxidized soybean oil on a carrier having an auxiliary stabilizer for a vinyl group.
• The elastomeric composition includes a prepolymer. Various prepolymers may be utilized in the present composition so long as they do not substantially hinder the desired viscoelastic, shock-attenuating attributes of the elastomeric compound. Typically, the prepolymer is an isocyanate.
• The thermoplastic component can include most any thermoplastic compound having elastomeric properties. In one embodiment of the gel, thermoplastic compounds comprising polyurethane are excluded. Acceptable thermoplastic component includes polydienes. An example polydiene includes polybutadiene. Typically, the activator or catalyst is an alkyl tin compound is also added to the gel compound. A specific example of an alkyl tin compound is a dioctyltin carboxylate.
• It is within the scope of the present invention to incorporate other additives such as fillers, pigments, surfactants, plasticizers, organic blowing agents, as stabilizers, and the like, in the manufacture of the reinforced polymeric shock absorbing envelope.
• Referring now in greater detail to the drawings in which like numerals indicate like items throughout the several views,FIGS. 1 and 2 depict multi-axial stretchable pad in various embodiments of the present invention.
• FIG. 1 illustrates an embodiment of the present multi-axialstretchable pad2 wherein theends10 of the pad are left open or not sealed. Depicted inFIG. 1 is the first opposed multi-axialstretchable layer4 and the second opposed multi-axial stretchable layer6. Disposed between the two opposed layers (4 and6) is a shock absorbing apolymer gel8.
• FIG. 2 depicts a further embodiment of the present multi-axialstretchable pad2 wherein theends10 of the pad are sealed. The ends may be sealed by any conventional means, for example, such are sewing and/or heat sealing. Further depicted is the first opposed multi-axialstretchable layer4 and the second opposed multi-axial stretchable layer6. Disposed between the two opposed layers (4 and6) is a shock absorbing apolymer gel8.
• While Applicants have set forth embodiments as illustrated and described above, it is recognized that variations may be made with respect to disclosed embodiments. Therefore, while the invention has been disclosed in various forms only, it will be obvious to those skilled in the art that many additions, deletions and modifications can be made without departing from the spirit and scope of this invention, and no undue limits should be imposed except as set forth in the following claims.

Claims (20)

1. A multi-axial stretchable pad comprising;

a first and a second opposed multi-axial stretchable layers; and

a shock absorbing a polymer gel residing between the first and second opposed multi-axial stretchable substrate layers.

2. The multi-axial stretchable pad ofclaim 1, wherein the layers are formed from a resilient polymeric material.

3. The multi-axial stretchable pad ofclaim 1, wherein the opposed layers are sealed to form an envelope containing the shock absorbing a polymer gel.

4. The multi-axial stretchable pad ofclaim 1, wherein the layers are formed from a woven material.

5. The multi-axial stretchable pad ofclaim 1, wherein the polymeric material comprises at least greater than 50% by weight of an epoxidized vegetable oil, a thermoplastic polymer; and a prepolymer.

6. The multi-axial stretchable pad ofclaim 5, further including an activator.

7. The multi-axial stretchable pad ofclaim 6, wherein the activator is an alkyl tin compound.

8. The multi-axial stretchable pad ofclaim 5, wherein the epoxidized vegetable oil is selected from the group consisting of soybean oil, linseed oil, and combinations thereof.

9. The multi-axial stretchable pad ofclaim 5, wherein the prepolymer comprises an isocyanate selected from the group of aliphatic, cycloaliphatic, araliphatic, aromatic, heterocyclic polyisocyaniates and combinations thereof.

10. The multi-axial stretchable pad ofclaim 5, wherein in the thermoplastic polymer is substantially free of a polyurethane.

11. The multi-axial stretchable pad ofclaim 5, wherein the thermoplastic polymer comprises a polydiene.

12. The multi-axial stretchable pad ofclaim 5, wherein the thermoplastic polymer is a polybutadiene.

13. The multi-axial stretchable pad ofclaim 5, wherein the polymeric gel comprises on a percent weight basis of the gel at least greater than about 50% of a vegetable based plasticizer, between about 20% and about 40% of a thermoplastic polymer, and between about 5% and about 20% of a prepolymer.

14. A method of forming a multi-axial stretchable pad comprising:

forming a shock absorbing envelope by sealing within a first and a second opposed multi-axial stretchable layers a polymeric gel.

15. The method of forming a multi-axial stretchable pad ofclaim 14 wherein the polymeric gel if formed by combining an epoxidized vegetable oil, a polydiene and a cyano group.

16. The method of forming a multi-axial stretchable pad ofclaim 15, wherein the polydiene is selected from polybutadiene, polyisoprene, polychloroprene, polynobornene, copolymers, terpolymers and combinations thereof.

17. The method of forming a multi-axial stretchable pad ofclaim 15, wherein the opposed first and second layer are sealed by fusing the two layers along the periphery of the pad.

18. A multi-axial stretchable pad comprising;

a first and a second opposed multi-axial stretchable layers; and

a shock absorbing a polymer gel residing between the first and second opposed multi-axial stretchable substrate layers, wherein the shock absorbing a polymer gel comprises at least greater than 50% by weight of an epoxidized vegetable oil.

19. The multi-axial stretchable pad ofclaim 18, wherein the gel comprises between about 20% to about 40% of the polydiene.

20. The multi-axial stretchable pad ofclaim 18, wherein the gel comprises up to about 5% by weight of the alkyl tin compound.

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