Method of making an auxetic mesh
A method of making an auxetic mesh, which method includes: (a) extruding a polymeric material 60 onto an open casting surface 58 that has an intended pattern 62 disposed therein, the pattern 62 being configured to create an auxetic mesh 20 ; (b) wiping off excess extruded polymeric material 60 from the open casting surface 64 ; (c) removing the cast mesh 20 from the open casting surface 64 after the excess polymeric material 60 has been wiped off; and (d) removing any residual polymeric material that is not of the intended mesh pattern 20 . The method allows for the continuous production of auxetic meshes.
1. A method of making an auxetic mesh, which method comprises:
(a) extruding a polymeric material onto an open casting surface that has an intended pattern disposed therein, the pattern being configured to create an auxetic mesh;
(b) wiping off excess extruded polymeric material from the open casting surface;
(c) separating a cast mesh from the open casting surface after the excess polymeric material has been wiped off; and
(d) removing any residual polymeric material that is not of the intended mesh pattern.
2. The method of claim 1 , wherein the polymeric material is allowed to cool before the cast mesh is removed from the open casting surface.
3. The method of claim 1 , wherein the residual polymeric material is removed by a step that includes burning the residual polymeric material.
4. The method of claim 1 , wherein the step (c) occurs before step (d).
5. The method of claim 1 , wherein the casting surface is disposed on a cylindrical role.
6. The method of claim 1 , wherein the auxetic mesh produced according to the method of claim 1 exhibits a Poisson ratio of less than −0.2.
7. The method of claim 1 , wherein the auxetic mesh produced according to the method of claim 1 exhibits a Poisson ratio of less than −0.4.
8. The method of claim 1 , wherein the auxetic mesh produced according to the method of claim 1 exhibits a Poisson ratio of less than −0.7.
9. The method of making an auxetic mesh of claim 8 , wherein the Poisson ratio is not further less than −2.2.
10. The method of claim 1 , wherein the auxetic mesh comprises a thermoplastic or thermoset polymeric material.
11. The method of claim 10 , wherein the polymeric material comprises a thermoplastic polymer selected from the group consisting of: a polyolefin, a halogenated polyolefin, a copolyester-ether elastomer, a copolyester elastomer, a polyamide, a copolymer of ethylene, an acrylonitrile polymer, an acrylic copolymer, a blend of polyethylene and polypropylene, and an elastomer block copolymer.
12. The method of claim 1 , wherein the polymeric material comprises polypropylene.
13. The method of claim 1 , wherein the polymeric material has a Young's modulus of 0.3 to 1900 Mega Pascals.
14. The method of claim 1 , wherein the polymeric material has a Young's modulus of 2 to 250 Mega Pascals.
15. The method of claim 1 , wherein the wiping step comprises forcing a blade against a rotating casting roll.
16. The method of claim 15 , wherein the blade also delivers molten polymer into cavities in the casting roll.
17. The method of claim 1 , wherein the residual polymeric material is removed by burning, heating, brushing, punching, or combinations thereof.