Shaped honeycomb
View Patent ↗This invention relates to a honeycomb comprising cells having edges forming a face of the honeycomb, the face defined by a plurality of points and having an area of curvature wherein at least two of the points are located in different tangential planes, the walls of the cells comprising 5 to 50 parts by weight thermoplastic material having a melting point of from 120° C. to 350° C., and 50 to 95 parts by weight of a high modulus fiber having a modulus of 600 grams per denier (550 grams per dtex) or greater, based on the total amount of thermoplastic material and high modulus fiber in the walls; wherein less than 25 percent of the honeycomb cells in the area of curvature have a re-entrant angle of greater than 180 degrees. This invention also relates to articles including panels and/or aerodynamic structures comprising the honeycomb.
1. A honeycomb comprising cells having edges forming a face of the honeycomb, the face defined by a plurality of points and having an area of curvature wherein at least two of the points are located in different tangential planes, the cells being expanded paper sheets bonded to each other along a number of node lines of applied adhesive;
the walls of the cells comprising a paper comprising:
a) 5 to 50 parts by weight thermoplastic material having a melting point of from 120° C. to 350° C., and
b) 50 to 95 parts by weight of a high modulus fiber having a modulus of 600 grams per denier (550 grams per dtex) or greater, based on the total amount of thermoplastic material and high modulus fiber in the walls,
wherein the high modulus fiber comprises para-aramid polymer, or the high modulus fiber is selected from the group of polybenzazole fiber, polypyridazole fiber, and mixtures thereof;
wherein less than 25 percent of the honeycomb cells in the area of curvature have a re-entrant angle of greater than 180 degrees, and
wherein the honeycomb has at least one face under compression and at least one face under tension.
2. The honeycomb of claim 1 wherein the high modulus fiber is present in an amount of from about 60 to 80 parts by weight.
3. The honeycomb of claim 1 wherein the thermoplastic material is present in an amount of from 20 to 40 parts by weight.
4. The honeycomb of claim 1 wherein the para-aramid polymer is poly (paraphenylene terephthalamide).
5. The honeycomb of claim 1 wherein the thermoplastic material comprises polyester polymer.
6. The honeycomb of claim 5 wherein the polyester polymer is a liquid crystalline polymer.
7. The honeycomb of claim 1 wherein the thermoplastic material is selected from the group consisting of polyolefin, polyamide, polyetherketone, polyetheretherketone, polyamide-imide, polyether-imide, polyphenylene sulfide, and mixtures thereof.
8. The honeycomb of claim 1 wherein the thermoplastic material is in the form of a fiber.
9. The honeycomb of claim 1 wherein the thermoplastic material is in the form of a fibrid.
10. The honeycomb of claim 1 wherein the thermoplastic material is in the form of a particle, flake, or powder.
11. The honeycomb of claim 1 further comprising a thermoset matrix resin.
12. An article comprising the honeycomb of claim 1 .
13. An aerodynamic structure comprising the honeycomb of claim 1 .
14. A panel comprising the honeycomb of claim 1 and a facesheet attached to a face of the honeycomb.