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EP-3475377-B1 - DISASSEMBLING METHOD

EP3475377B1EP 3475377 B1EP3475377 B1EP 3475377B1EP-3475377-B1

Inventors

  • ZHAO, BIN
  • MCCARTHY, Conor

Dates

Publication Date
20260506
Application Date
20170627

Claims (13)

  1. A method of disassembling at least two parts of an article which are joined by a cured adhesive composition comprising a thermoset polymer and particles susceptible to dielectric heating, the method comprising the steps of: i) exposing the cured adhesive composition to electromagnetic energy having a frequency in the range of from 10 MHz to 20 GHz to heat the particles susceptible to dielectric heating comprised within the cured adhesive composition; ii) separating the at least two parts of the article from each other; wherein the particles susceptible to dielectric heating are selected from any one or more of: hollow nanospheres having an outer shell with a thickness of from 10 nm to 100 nm and a diameter of from 150 nm to 2,000 nm; graphene or graphene derivative having a sheet length of from 10 nm to 200 nm; and carbon nanofibers having a diameter of 100 nm to 200 nm and a length of 20 µm to 200 µm, all the dimensions being determined as indicated in the description.
  2. The method according to claim 1, wherein the electromagnetic radiation has a frequency of from 10 MHz to 50 MHz.
  3. The method according to claim 1, wherein the electromagnetic radiation has a frequency of from 800 MHz to 5 GHz.
  4. The method according to any of claims 1 to 3, wherein the adhesive composition according to claim 1, wherein the thermoset polymer comprises an epoxy resin.
  5. The method according to claim 4, wherein the epoxy resin is a modified epoxy resin selected from any one or more of polyurethane modified epoxy resin, isocyanate modified epoxy resin, polysulfone modified epoxy resin, phenolic modified epoxy resin, nylon modified epoxy resin, polysulfide rubber modified epoxy resin, nitrile modified epoxy resin, silicone modified epoxy resin and acrylic epoxy resin.
  6. The method according to any of claims 1 to 5, wherein the particles susceptible to dielectric heating are hollow nanospheres of Fe 3 O 4 , Co 3 O 4 , ZnO, Co/Ni alloy or carbon.
  7. The method according to any of claims 1 to 6, wherein the particles susceptible to dielectric heating are hollow nanospheres of Fe 3 O 4 .
  8. The method according to any of claims 1 to 5, wherein the particles susceptible to dielectric heating are graphene or a graphene derivative.
  9. The method according to any of claims 1 to 5, wherein the particles susceptible to dielectric heating are carbon nanofibres.
  10. The method according to any of claims 1 to 5, wherein the particles susceptible to dielectric heating are a combination of carbon nanofibres and Fe 3 O 4 hollow nanospheres.
  11. The method according to any of claims 1 to 10, wherein the particles susceptible to dielectric heating are present in the adhesive composition in an amount of from 0.01 wt% to 10 wt%.
  12. The method according to any of claims 1 to 11, wherein the adhesive composition comprises a curing agent present in the adhesive composition in an amount of from 10 to 40 wt%.
  13. The method according to any one of claims 1 to 12, wherein the at least two parts of an article which are joined by a cured adhesive composition were joined together by a method comprising the steps of: a) providing a join between the at least two parts of the article with an adhesive composition comprising a thermosetting resin and the particles susceptible to dielectric heating; b) causing the adhesive composition to cure to produce the cured adhesive composition comprising the thermoset polymer and the particles susceptible to dielectric heating by exposing the adhesive composition to electromagnetic radiation to accelerate curing of the adhesive composition.

Description

Field The present invention relates to a method of disassembling at least two parts of an article which are joined by a cured adhesive composition and an article comprising a join. In particular the invention relates to methods of disassembling adhesive compositions comprising particles susceptible to dielectric heating. Background There are several conventional techniques used in industry to create a bond between parts or components of mechanical/electrical equipment and infrastructure. These conventional techniques include welding, riveting, screwing, etc. Such mechanical fastening methods have been preferred by designers and engineers but can be very inefficient and expensive, for example there can be over a million fasteners in a commercial passenger aircraft. Therefore, there is a need to develop more efficient joining techniques. Adhesives have been used as an alternative to mechanical fastening to join parts or components together. Joining composite materials to metals is likely to become more important as new high performance hybrid structures are developed such as light-weight aircraft, electric cars, ship hulls and wind/wave energy turbine blades formed from or containing parts formed from composite materials. However, it can be difficult to join composite materials to metals using adhesives, due mainly to a significant mismatch in their thermal expansion coefficients and their vastly different surface chemistries, which makes bonding very difficult. Therefore, there is a need to develop more efficient joining techniques which are suitable for composite materials. Adhesives comprising a thermosetting resin (termed "thermosetting adhesives") form on curing a highly cross-linked 3-dimensional polymer structure. This highly cross-linked structure produced by chemical bonds in the thermosetting resin provides high mechanical and physical strength (to support high stress or load) and high stability (to resist degradation by temperature, weather, aging, water and solvents) compared with thermoplastic polymers. Additionally, thermosetting adhesives are generally modified by the addition of elastomer, rubber, thermoplastic polymer and copolymer in order to enhance the impact stress and peel strength. Thermosetting adhesives are therefore considered to be promising alternatives to conventional joining technology. Bonding using thermosetting adhesives may provide the following advantages: 1) a reduction in the number of machine components such as screws, nuts, washers and rivets that are necessary for the joining process, which can reduce the manufacturing cost of the overall joining process;2) an improvement in stress distribution, in which the stresses are homogeneously distributed over the entire bonding area thereby minimizing high localized stress concentrations, in order to enhance the fatigue resistance to mechanical shock and vibration upon prolonged exposure to hostile environmental conditions;3) an improvement in humidity and corrosion resistance at both ambient and elevated temperature conditions;4) a more convenient method to join substrates with different geometries, sizes and composition (such as wood, plastic, metal, glass, composites);5) a reduction of the product weight which is particularly important in the development of more energy efficient vehicles (cars, ships, trains etc). US 2015328847 A1 discloses a method of repairing a polymeric composite workpiece. The method includes detecting and identifying a localised area of a polymeric composite workpiece having a defect. A resin is applied to the localised area. The method includes introducing radiofrequency electromagnetic radiation adjacent to the resin to selectively induce localised heating and/or curing of the resin. US 2006289113 A1 discloses a method of manufacturing a component having two individual or shaped parts to be connected using an adhesive containing a magnetic filler and capable of being cured by heat. At least one part of the component, in particular, the adhesive joint lying between the parts, is exposed to circularly polarised electromagnetic radiation, particularly in the microwave wavelength range, in order to apply heat to the adhesive. WO 2009147415 A1 discloses a resin material comprising at least one thermoset resin, carbon conductive additive material, and at least one thermoplastic polymer resin. The thermoplastic polymer resin dissolves in the thermoset polymer resin and phase separates upon cure. US 2016015652 A1 discloses hollow, double-shelled sub-micrometre particles generated through a rapid aerosol-based process. The inner shell is an essentially hydrophobic carbon layer of nanoscale dimension (5-20 nm), and the outer shell is a hydrophilic silica layer of approximately 5-40 nm, with the shell thickness being a function of the particle size. US 6855760 B1 discloses adhesive compositions of which the binder system contains nanoscale particles with ferromagnetic, ferrimagnetic, superparamagnetic or piezoe