Improvements in or relating to foam filled honeycomb structures

Patent metadata

Field	Value
Publication number	US-2016243733-A1
Application number	US-201415030618-A
Country	US
Kind code	A1
Filing date	Oct 20, 2014
Priority date	Oct 21, 2013
Publication date	Aug 25, 2016
Grant date	—

Abstract

Spherical heat foamable pellets ( 2 ) are used for reinforcing honeycomb structures ( 4 ). The pellets are preferably of average diameter from 0.5 mm to 0.9 mm and preferably at least 80% of the pellets have a diameter in this range. The pellets can form a free flowing stream which can be poured into the cells ( 5 ) of the honeycomb where they can be foamed by heating to form a reinforcing foam which can also bond the honeycomb structure to facing sheets. It is preferred that the pellets are based on a thermosetting resin and contain a curing agent that can cure the foamed resin to produce an integral rigid reinforcing foam within the cells of the honeycomb.

First claim

1 . The use of substantially spherical pellets for strengthening a sandwich panel comprising a honeycomb core wherein the pellets comprise a polymer and a thermally activated blowing agent.

2 . The use according to claim 1 in which the average diameter of the pellets is in the range 0.5 mm to 0.9 mm.

3 . The use according to claim 1 in which the polymer is a thermosetting resin and the pellet further includes a thermally activated curing agent.

4 . The use according to claim 1 in which the polymer is an epoxy resin.

5 . The use according to claim 1 in which at least 80% of the pellets have a diameter in the range of 0.5 mm to 0.9 mm.

6 . Substantially spherical pellets of average diameter in the range of 0.5 mm to 0.9 mm wherein the pellets comprise a thermosetting resin, a thermally activated blowing agent and a thermally activated curing agent for the thermosetting resin.

7 . Substantially spherical pellets according to claim 6 in which the thermosetting resin is an epoxy resin.

8 . Substantially spherical pellets according to claim 6 wherein at least 80% of the pellets have a diameter in the range of 0.5 mm to 0.9 mm.

9 . A honeycomb structure in which at least some of the cells are filled by a foam obtained by providing substantially spherical pellets comprising a polymer and a thermally activated blowing agent and heating to cause the pellets to foam.

10 . The honeycomb structure of claim 9 in which the average diameter of the pellets is in the range 0.5 to 0.9 mm.

11 . A honeycomb structure according to claim 10 in which the polymer is a thermosetting resin and the pellets contain a curing agent for the thermosetting resin.

12 . A honeycomb structure according to claim 10 in which at least 80% of the pellets have a diameter in the range 0.5 mm to 0.9 mm.

13 . A honeycomb structure according to claim 10 provided with a facing sheet on at least one surface, preferably on both surfaces.

14 . A honeycomb structure according to claim 11 wherein the thermosetting resin is an epoxy resin.

15 - 19 . (canceled)

20 . A honeycomb structure according to claim 13 wherein one or both of the facing sheets comprise a prepreg of fibres in a curable matrix.

21 . A honeycomb structure according to claim 20 in which the curable matrix is cured at the temperature used to foam the pellets.

22 . A honeycomb structure according to claim 20 in which the curable matrix is an epoxy resin.

Assignees

• Zephyros Inc

Inventors

• Meyer Francis
• Chene Morgan

Classifications

• B32B3/12

  characterised by a layer of regularly- arranged cells, e.g. a honeycomb structure · CPC title

• B29C44/445

  in the form of expandable granules, particles or beads · CPC title

• B32B27/065

  of foam · CPC title

• B32B27/38

  comprising epoxy resins · CPC title

• B29K2063/00

  Use of {EP, i.e.} epoxy resins {or derivatives thereof}, as moulding material · CPC title