Welded structural joint between a high-performance thermoplastic matrix composite material and an elastomer by powder functionalization

Patent metadata

Field	Value
Publication number	US-10118342-B2
Application number	US-201414781580-A
Country	US
Kind code	B2
Filing date	Mar 25, 2014
Priority date	Apr 3, 2013
Publication date	Nov 6, 2018
Grant date	Nov 6, 2018

Abstract

A method for producing, by welding, a joint between a thermoplastic matrix composite material and an elastomeric material. The elastomeric material is functionalized by forming a thin layer of elastomeric material incorporating particles of thermoplastic material and melting the thin layer onto the surface of the elastomeric material during the pressure-vulcanization of the elastomer. The functionalized surface of the elastomeric material is welded to the thermoplastic material of the composite. The welding operation includes interposing a metal fabric coated with thermoplastic material between the surfaces of the elastomer and the composite that are welded to each other, and passing an electric current through same, resulting in the surface melting of the two materials.

First claim

The invention claimed is:

1. A method for producing a welded structural joint between a thermoplastic matrix composite and an elastomer, comprising the steps of:
providing a functionalized elastomeric material layer by incorporating a predetermined proportion of a powder of a thermoplastic material in a thin layer of raw elastomeric material;
applying the functionalized elastomeric material layer onto a main layer of the elastomeric material;
fusing the functionalized elastomeric material layer with the main layer of the elastomeric material during a step of vulcanization of both the functionalized elastomeric material layer and the main layer of the elastomeric material under pressure; and
welding a thermoplastic composite material of the thermoplastic matrix composite to the functionalized elastomeric material layer.

2. The method as claimed in claim 1 , wherein the step of functionalizing comprises the steps of:
cleaning various parts of a vulcanizing mold;
preparing a pre-functionalized thin layer of raw elastomer by incorporating homogeneously the predetermined proportion of the powder of the thermoplastic material in the pre-functionalized thin layer of elastomer;
applying the pre-functionalized thin layer of raw elastomer on a surface of the elastomeric material;
vulcanizing the elastomeric material under a pressure so that the pre-functionalized thin layer of raw elastomer becomes incorporated in the main layer of the elastomeric material, at least at the surface, during the vulcanizing process.

3. The method as claimed in claim 1 , further comprising the step of selecting the thermoplastic material incorporated in the thin layer of the raw elastomeric that is both weldable to a thermoplastic material forming the thermoplastic matrix composite and compatible with the elastomeric material.

4. The method as claimed in claim 3 , wherein the thermoplastic material incorporated in the thin layer of raw elastomeric material is identical to the thermoplastic material forming the thermoplastic matrix composite.

5. The method as claimed in claim 1 , wherein the thermoplastic composite material is a carbon/polyetheretherketone composite; wherein the elastomeric material is of a hydrogenated nitrile butadiene rubber type; and wherein the thermoplastic material incorporated in the thin layer of raw elastomeric material is a polyetherimide.

6. The method as claimed in claim 5 , further comprising the step of incorporating the thermoplastic material in the raw elastomeric material in a form of particles with a diameter between 20 μm and 60 μm, in a proportion between 10% and 25% of the mixture by weight.

7. The method as claimed in claim 1 , wherein the step of welding comprises the steps of heating faying surfaces of two materials to be welded by interposing a woven metal wire cloth between the faying surfaces of the two materials, the woven metal wire cloth functions as a heating resistance and the woven metal wire cloth is impregnated with a thermoplastic material.

8. The method as claimed in claim 7 , further comprising the step of preparing the faying surfaces of the two materials to be assembled prior to the step of welding.

9. The method of claim 8 , wherein the step of preparing comprises the steps of degreasing using a solvent, and cleaning the faying surfaces of the two materials with the solvent.

10. The method of claim 8 , wherein the step of preparing comprises the steps of grinding a functionalized surface of the elastomeric material forming the elastomer, and cleaning the surface of the functionalized layer with a solvent.

11. The method as claimed in claim 1 , wherein the thermoplastic composite material is a carbon/polyetheretherketone composite; wherein the elastomeric material is of a hydrogenated nitrile butadiene rubber type; and wherein the step of functionalizing the elastomeric material comprises the steps of:
setting up the following elements on a bottom plate of a vulcanizing mold and covering the elements with a top plate of the vulcanizing mold to provide a stack:
a first set of two superposed layers of Teflon-coated glass cloth;
a sheet of raw elastomeric material in which a polyetherimide powder has been incorporated therein;
sheets of unvulcanized raw elastomeric material;
a set of edging blocks; and
a second set of two superposed layers of Teflon-coated glass cloth; and

placing the stack on plate of a heating press preheated to a temperature θ 2 of 140° C.;
hot pressing the stack by applying a nominal pressing cycle of the elastomer in question is applied;
removing the vulcanizing mold from the heating press which maintains the temperature θ 2 of 140° C.; and
removing the functionalized layer of elastomeric material from the vulcanizing mold to cool to a room temperature.

12. The method as claimed in claim 11 , wherein the nominal pressing cycle comprises:
a phase of gradual increase in temperature to a high temperature θ 1 of 230° C. at a gradient of 2.5° C./min;
a phase of maintaining a temperature θ 1 for 10 minutes; and
a phase of temperature decrease to the temperature θ 2 of 140° C. at a gradient of 2.5° C./min.

13. The method as claimed in claim 1 , wherein the thermoplastic composite material is a carbon/polyetheretherketone composite; wherein the elastomeric material is of a hydrogenated nitrile butadiene rubber type, and wherein the step of welding comprises the steps of:
setting up and arranging the following elements in order on a plate of heat-insulating material to provide a stack:
a first film of heat-resistant polyimide;
the functionalized elastomeric material;
a first film of polyetherimide;
a woven metal wire cloth pre-impregnated with polyetherimide;
a second film of polyetherimide;
the thermoplastic composite material;
a second film of heat-resistant polyimide;
a layer of heat-insulating material; and
a glass cloth;

producing a bladder under a vacuum with a third film of heat-resistant polyimide arranged to allow the woven metal wire cloth to stand out and ensuring a hermeticity of the bladder by a high-temperature mastic;
placing the bladder under the vacuum, connecting an electric power supply unit to the woven metal wire cloth, and applying different values of current according to a predetermined cycle;
removing the third film of heat-resistant polyimide serving as a vacuum enclosure and dismounting the stack.

14. The method as claimed in claim 13 , further comprising the steps of applying a current of 15.6 amps to the woven metal wire cloth for 200 seconds, and then applying a current of 10 amps to the woven metal wire cloth for 100 seconds.

Assignees

• Airbus Defence & Space Sas
• Arianegroup Sas

Inventors

• Menochet Audrey
• Colin Christophe

Classifications

• B29C66/91655

  by controlling or regulating the current intensity · CPC title

• C08J2300/22

  Thermoplastic resins · CPC title

• B29C66/7212

  characterised by the composition of the fibres · CPC title

• B32B2260/046

  Synthetic resin · CPC title

• B29C66/712 Primary

  the composition of one of the parts to be joined being different from the composition of the other part · CPC title