# US 10,118,342 B2 · Welded structural joint between a high-performance thermoplastic matrix composite material and an elastomer by powder functionalization

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- Number: US 10,118,342 B2
- Document ID: US10118342B2
- Status: Granted
- Kind: B2
- Application number: 14/781,580
- Filed: 2014-03-25
- Published: 2016-03-03
- Granted: 2018-11-06
- Earliest claimed: 2013-04-03
- Assignees: Arianegroup SAS
- Applicants: Airbus Defence and Space SAS
- Inventors: Audrey Menochet; Christophe Colin
- Web page: https://patentgrep.com/patent/US10118342B2

## CPC

- B29C 66/712: {the composition of one of the parts to be joined being different from the composition of the other part}
- B29C 65/20: with direct contact, e.g. using "mirror"
- B29C 65/344: {being a woven or non-woven fabric or being a mesh}
- B29C 65/348: {with a polymer coating}
- B29C 65/364: {being a woven or non-woven fabric or being a mesh}
- B29C 65/4815: {Hot melt adhesives, e.g. thermoplastic adhesives}
- B29C 65/4835: {Heat curing adhesives}
- B29C 65/486: {characterised by their physical form being non-liquid, e.g. in the form of granules or powders (B29C65/50 takes precedence)}
- B29C 65/5021: {being multi-layered}
- B29C 65/5057: {positioned between the surfaces to be joined (B29C65/5035 takes precedence)}
- B29C 66/1122: {Single lap to lap joints, i.e. overlap joints (B29C66/45, B29C66/472, B29C66/52272 take precedence)}
- B29C 66/45: {Joining of substantially the whole surface of the articles (methods or apparatus for laminating B32B37/00)}
- B29C 66/721: {Fibre-reinforced materials (B29C66/729 takes precedence)}
- B29C 66/7212: {characterised by the composition of the fibres}
- B29C 66/73751: {the to-be-joined area of at least one of the parts to be joined being uncured, i.e. non cross-linked, non vulcanized}
- B29C 66/73752: {the to-be-joined areas of both parts to be joined being uncured}
- B29C 66/73755: {the to-be-joined area of at least one of the parts to be joined being fully cured, i.e. fully cross-linked, fully vulcanized}
- B29C 66/7392: {characterised by the material of at least one of the parts being a thermoplastic}
- B29C 66/742: {to metals or their alloys}
- B29C 66/7465: {Glass}
- B29C 66/81455: {being a fluid inflatable bag or bladder, a diaphragm or a vacuum bag for applying isostatic pressure (inflatable element positioned between the joining tool and a backing-up part B29C66/82421)}
- B32B 25/08: of synthetic resin
- B32B 25/10: next to a fibrous or filamentary layer
- B32B 27/08: of synthetic resin
- B32B 27/12: next to a fibrous or filamentary layer
- B32B 27/18: characterised by the use of special additives
- B32B 27/281: {comprising polyimides}
- C08J 5/121: {by heating}
- C08J 5/242: {using metal fibres}
- C08J 5/248: {using pre-treated fibres}
- B29C 35/02: Heating or curing, e.g. crosslinking or vulcanizing {during moulding, e.g. in a mould}(cold vulcanisation B29C35/18 {; vulcanising tyres, presses therefor B29D30/0601})
- B29C 65/02: by heating, with or without pressure
- B29C 66/02: {Preparation of the material, in the area to be joined, prior to joining or welding (B29C66/32 takes precedence)}
- B29C 66/02245: {Abrading, e.g. grinding, sanding, sandblasting or scraping}
- B29C 66/71: {characterised by the composition of the plastics material of the parts to be joined (welding bar compositions B29C65/125)}
- B29C 66/91443: {following a temperature-time profile (B29C65/38 takes precedence)}
- B29C 66/91645: {by steps}
- B29C 66/91655: {by controlling or regulating the current intensity}
- B29C 66/919: {characterised by specific temperature, heat or thermal flux values or ranges (specific electrical resistance values B29C66/81262)}
- B29C 66/949: {characterised by specific time values or ranges}
- B29C 2035/0211: {resistance heating (B29C2035/0811 takes precedence)}
- B29K 2071/00: Use of polyethers {, e.g. PEEK, i.e. polyether-etherketone or PEK, i.e. polyetherketone or derivatives thereof}, as moulding material
- B29K 2995/0005: Conductive
- B29K 2995/0046: Elastic
- B29K 2995/0087: Wear resistance
- B29L 2007/008: {Wide strips, e.g. films, webs}
- B29L 2009/00: Layered products
- B29L 2031/3097: {Cosmonautical vehicles; Rockets}
- B32B 2260/021: Fibrous or filamentary layer
- B32B 2260/046: Synthetic resin
- B32B 2262/101: Glass fibres
- B32B 2262/103: Metal fibres
- B32B 2307/304: Insulating
- B32B 2307/306: Resistant to heat
- C08J 2300/22: Thermoplastic resins
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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.

### Claim 4 (depends on 3)

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.

### Claim 5 (depends on 1)

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.

### Claim 6 (depends on 5)

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.

### Claim 7 (depends on 1)

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.

### Claim 8 (depends on 7)

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.

### Claim 9 (depends on 8)

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.

### Claim 10 (depends on 8)

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.

### Claim 11 (depends on 1)

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 θ2 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 θ2 of 140° C.; and
removing the functionalized layer of elastomeric material from the vulcanizing mold to cool to a room temperature.

### Claim 12 (depends on 11)

The method as claimed in claim 11, wherein the nominal pressing cycle comprises:
a phase of gradual increase in temperature to a high temperature θ1 of 230° C. at a gradient of 2.5° C./min;
a phase of maintaining a temperature θ1 for 10 minutes; and
a phase of temperature decrease to the temperature θ2 of 140° C. at a gradient of 2.5° C./min.

### Claim 13 (depends on 1)

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.

### Claim 14 (depends on 13)

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.