Method of treating auxiliary article for use in manufacture of article comprising epoxy polymer

Abstract

A method of treating an auxiliary article for use in the manufacture of an article comprising an epoxy polymer is provided. The method includes providing an auxiliary article for use in the manufacture of an epoxy polymer, wherein the auxiliary article is contaminated by a contaminant including an uncured, partially cured, and / or fully cured epoxy polymer. Further, the contaminated auxiliary article is exposed to a release agent to release contaminants from the auxiliary article and form contaminant by-products including the release agent and the contaminants, ultimately separating the auxiliary article from the contaminant by-products. In the method, the epoxy polymer is an acid-cleavable epoxy polymer, and the release agent includes an acid.

Description

Technical Field

[0001] The present disclosure generally relates to methods of treating auxiliary items used in the manufacture of articles comprising epoxy polymers. Background Art

[0002] Composite structures, such as wind turbine blades, are typically manufactured using epoxy resin infusion technology, which uses a vacuum to draw liquid resin into a molded reinforcement structure, where the resin then cures to form a solid part. To facilitate the handling of the resin, various auxiliary items are used, such as vacuum bags, resin tubes, and distribution media. Currently, these items are considered non-recyclable waste after a single infusion. This is mainly due to the challenges of removing epoxy resin at different stages of cure from the auxiliary items. In addition, reusable items, such as molds and tools, sometimes need to be scraped off if they become (excessively) contaminated with epoxy resin.

[0003] While many auxiliary items often comprise materials with well-established recycling pathways, there are currently no established reuse or recycling pathways for these items once they become contaminated with cured, partially cured, and / or uncured resin during the infusion process.

[0004] The present invention was born in such background. Summary of the Invention

[0005] According to one aspect of the present invention, a method for the auxiliary object used in the manufacture of epoxy polymer is provided. The method comprises the auxiliary object used in the manufacture of the article that is provided in epoxy polymer, wherein the auxiliary object is polluted by pollutants. Pollutants comprise uncured, partially cured and / or fully cured epoxy polymer. In other words, pollutants comprise epoxy polymer (its form can be cured epoxy polymer resin matrix), oligomer (its form can be partially cured epoxy polymer resin assembly) and / or monomer (its form can be uncured epoxy polymer liquid resin). In certain embodiments, pollutants comprise partially cured and uncured epoxy resin. In certain embodiments, pollutants comprise fully cured epoxy polymer.

[0006] The method also includes exposing the contaminated auxiliary object to a releasing agent to release the pollutant from the auxiliary object and forming a pollutant by-product comprising the releasing agent and the pollutant. At this stage, the pollutant can exist in the form of, for example, swollen epoxy particles or dissolved or suspended epoxy monomers or oligomers. Preferably, the pollutant by-product comprises swollen epoxy particles because such particles can be separated from the pollutant by-product by, for example, filtering and recycled or reused as a filler by, for example, depolymerization. Finally, the method includes separating the auxiliary object from the pollutant by-product.

[0007] Epoxy polymer is an acid-cleavable epoxy polymer, and the releasing agent comprises acid.Herein, acid-cleavable epoxy polymer refers to can swell when contact comprises the releasing agent of acid, thereby mechanically fractures part chemical bond, forms the epoxy polymer particle of swelling, or can be chemically decomposed into monomer and / or oligomer epoxy polymer.The process that acid-cleavable epoxy polymer is swollen into the epoxy polymer particle of swelling is referred to as swelling, acid cracking or disintegration interchangeably in this article.Acid-cleavable epoxy polymer can be for example an epoxy polymer based on amine-cured epoxy resin, for example OlinAirstone760, HexionRIMR035C perfusion epoxy resin, AdityaBirlaRecyclamine system.In other words, the epoxy polymer based on amine-cured epoxy resin constitutes the subclass of acid-cleavable epoxy polymer.In the method according to the present invention, preferably, epoxy polymer (that is, the uncured, partially cured or fully cured epoxy polymer included in the pollutant) is based on amine-cured epoxy resin.

[0008] Releasing contaminants from auxiliary articles and separating the auxiliary articles from the contaminant byproducts can result in cleaner articles that can then be reused or processed for recycling. In other words, one aspect of the present invention relates to a method for recycling auxiliary articles used in the manufacture of articles comprising epoxy polymers, which auxiliary articles are contaminated with uncured, partially cured, and / or fully cured epoxy polymers. Specifically, it has been observed that consumables comprising or consisting of thermoplastic polymers, such as vacuum bags, tubes, and valves used in the manufacture of articles comprising epoxy polymers, can be more easily recycled, for example, by remelting and molding, after removal of epoxy polymer contaminants.

[0009] In some embodiments, pollutants can be extracted from the pollutant by-products and subsequently reused or recycled. The extraction process can, for example, include regulating the pH value of the pollutant by-products and / or filtering, drying (for example, in a baking oven or by spray drying), and then separating the swollen epoxy particles by filtering or a cyclone separator. The extraction process can include distilling the pollutant by-products, preferably under reduced pressure. The extraction process can also include separating by cooling the pollutant by-products, and optionally combining with filtration. In this way, the waste generated in the manufacturing of components (such as wind turbine blades) comprising epoxy polymers can be reduced. For example, monomers and / or oligomers of the epoxy polymers chemically decomposed can be physically separated from the pollutant by-products by phase separation or distillation, or by chemical separation. The recycling of pollutants can include depolymerizing the pollutants when the pollutant is a partially cured or fully cured epoxy polymer resin, preferably reducing it to a monomer, such as bisphenol A (BPA). Since BPA has no natural sources and is produced from fossil-based raw materials, it is highly desirable to recover BPA through the recycling of epoxy polymers (which otherwise might end up in landfills due to the complexity of mixing epoxy resins with auxiliary materials). The release agent can be recovered during the process, for example as a pass-through fraction in a filter or by condensation of gases after spray drying and cyclone separation of solids. The release agent (optionally with a small amount of residual contaminants) can then be reused as a release agent (optionally after processing, such as purification or composition adjustment), or the release agent can be recycled, in which case it is preferred to extract all contaminants (not just some of them) from the contaminated byproducts before the release agent is recycled.

[0010] The method may include extracting at least a portion of the pollutants from the pollutant byproduct and then reusing the polluted byproduct as a releasing agent. Optionally, the polluted byproduct to be reused as a releasing agent may be further processed, such as purified or adjusted in composition, before use.

[0011] The pollutants may include inert components that can be released from the auxiliary object into the pollutant byproduct. The inert components can be non-swellable polymer components (e.g., non-acid cleavable epoxy resins, thermoplastic polymers, or polyesters), metal components (e.g., sensors, lightning conductors, lightning receptors, or fasteners), fiber components (such as glass fibers, carbon fibers, or composite materials comprising such fibers and an inert matrix material), or particle components (e.g., ceramic, glass, or inert polymer particles).

[0012] Surprisingly, the release rate of the pollutants is particularly rapid when the release agent comprises an organic acid, particularly when the release agent comprises formic acid and / or acetic acid. In particular, the release agent comprising formic acid is able to provide rapid release at relatively high acid concentrations, such as formic acid concentrations greater than 50% by weight in aqueous solution, preferably formic acid concentrations of 60% to 100% by weight in aqueous solution, and more preferably formic acid concentrations of 75% to 95% by weight in aqueous solution.

[0013] Exposing the contaminated auxiliary article to the release agent may include spraying, immersing, and / or rinsing the auxiliary article in or with the release agent.

[0014] In order to speed up the release rate of pollutants from the auxiliary object, the release agent can be heated before or during the exposure of the auxiliary object to the release agent. For example, the release agent can be heated to at least 25°C, at least 40°C or (most preferably) at least 50°C, the higher the temperature, the faster the pollutant release rate. On the other hand, too high a temperature is not preferred because it may lead to degradation of the auxiliary object, excessive evaporation of the release agent and / or excessive energy consumption. The release agent is preferably heated to below 90°C, more preferably below 80°C. For example, the release agent can be heated in a container with an internal or external heating device before being sprayed onto the auxiliary object. Alternatively or additionally, the release agent can also be heated in a container in which the auxiliary object with the pollutants is immersed or otherwise immersed. Alternatively or additionally, the auxiliary object with the release agent can be placed or transported through an oven to heat the release agent after the auxiliary object is exposed.

[0015] This method can be included in before, during or after the contaminated auxiliary object is exposed to the releasing agent, the contaminated auxiliary object is carried out mechanical treatment.Mechanical treatment can for example be divided into fragments with pollutant, pollutant is peeled off from the auxiliary object surface and / or the contaminated auxiliary object is divided into smaller fragments.In some cases, mechanical treatment can make pollutant contact with releasing agent better or faster in the process that contaminated product is exposed to releasing agent.In some cases, mechanical treatment can make auxiliary object and pollutant by-product faster and / or more thoroughly separated.In some cases, mechanical treatment can remove part pollutant from contaminated auxiliary object before contaminated auxiliary object is exposed to releasing agent, thereby for example shorten the contact time between releasing agent and the contaminated auxiliary object, and / or reduce the pollutant amount that needs to separate from pollutant by-product before reuse releasing agent. Mechanical treatment may, for example, include impacting, bending, compressing, tearing, scraping, brushing, (high-pressure) cleaning with air or water, vacuuming, rubbing, shaking and / or rinsing the contaminated auxiliary items, and optionally include or subsequently separate the mechanically released contaminants from the contaminated auxiliary items.

[0016] The method may include mechanically treating the contaminated auxiliary article during and / or after exposing the contaminated auxiliary article to the release agent, as this has been found to be advantageous in accelerating the release of the contaminants and / or reducing the amount of contaminants remaining on the auxiliary article after the method has been implemented. Mechanical treatment may be, for example, brushing, (high-pressure) washing with air or water, vacuum cleaning, rubbing and / or shaking. It can be inferred (but not limited to) that the positive effect of mechanical treatment may be due to: in particular, it helps to reach deep layers of the contaminant during the release process; after the release process, it helps to remove swollen epoxy particles that are loosely adhered to the auxiliary article; and / or mechanically breaking up the contaminant into fragments or stripping the contaminant from the surface of the auxiliary article.

[0017] Auxiliary items may include thermoplastic materials and / or may include secondary items or consumables used in manufacturing composite wind turbine blades, such as vacuum bags, dispensing media, hoses or tubes, valves, tools (such as spatulas, buckets, brushes, rollers, molds, etc.).

[0018] Auxiliary object may comprise confined space, and this confined space may be polluted by pollutant.In this article, confined space refers to the space that mode of access is limited or restricted.Therefore, the example of confined space is the structure with through hole or blind hole, for example pipe, hose, pipeline, bucket, cup and other partially closed containers in this article.Herein, the method can also be included in before or during the auxiliary object being exposed to the releasing agent by contaminated, mechanically remove at least part of pollutant from confined space.Mechanical removal can for example be by excavating, scraping, pushing (for example by pressurized air or liquid, such as water, solvent and / or releasing agent), pulling (for example by vacuum or the tool with hook-like feature), cracking (for example by impact, bending or compression pollutant and / or auxiliary object) and / or peeling off auxiliary object or pollutant.Preferably, mechanical removal operation should be carried out when pollutant is uncured or partially cured and has certain fluidity, because like this be conducive to carry out mechanical removal by non-contact mode (such as by vacuum or pressurized air), and avoid further contaminating other auxiliary objects. The mechanically removed contaminants can be combined with contaminant byproducts, where they swell and / or chemically decompose, and then recovered along with the contaminant-swollen epoxy particles or chemically decomposed epoxy polymer. Mechanically removing at least a portion of the contaminants from the confined space can shorten the distance the release agent has to swell or chemically decompose into the contaminants, thereby shortening the time it takes for the contaminants to be released from the auxiliary article.

[0019] The auxiliary article can be used in the manufacture of various articles comprising an acid-cleavable epoxy polymer, such as articles coated with an acid-cleavable epoxy polymer-based coating, electrical systems and electronic equipment, adhesives, and fiberglass-reinforced component articles (e.g., boats, kayaks, swimming pools, or composite components). Due to the size of wind turbine blades and the number of consumables (such as vacuum bags and other auxiliary articles) used in the manufacture of wind turbine blades, it has been found to be particularly advantageous that the auxiliary article is an auxiliary article used in the manufacture of wind turbine blades.

[0020] The method of any one of the preceding claims, wherein the release agent further comprises an organic solvent, a surfactant, a colorant and / or a salt. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order that this may be more fully understood, the present invention will now be described, by way of example only, with reference to the following drawings, in which like features are assigned like reference numerals, and in which:

[0022] Figures 1a to 1c Schematic diagram of a general resin infusion device. Figure 1a It is a device before resin infusion; Figure 1b It is a device used in the resin infusion process; Figure 1c The device is completed after resin infusion.

[0023] Figure 2 is a flowchart of a method for processing an auxiliary object according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In summary, embodiments of the present invention provide a method for treating an auxiliary article that has come into contact with a liquid epoxy polymer resin system during the manufacture of an article comprising epoxy polymers, such as a composite material, preferably a wind turbine blade, and has thereby become contaminated with uncured, partially cured, and / or fully cured epoxy polymer. The method comprises exposing the contaminated article to a release agent comprising an acid to remove any resin system adhering to the surface of the article. The release agent reacts with the resin system, causing it to swell and / or allowing it to chemically decompose and release from the surface of the article. After removing the resin system from the article, a clean auxiliary article is obtained, which can be reused or recycled for its raw materials.

[0025] To provide background information for the present invention, Figures 1a to 1cA schematic diagram of a typical resin infusion process, which can be used to manufacture part or all of a composite wind turbine blade, is shown. As shown, an assembly of reinforcement material 2 is placed within a mold cavity 4 and covered with vacuum bagging material 6. In this example, the assembly of reinforcement material 2 includes multiple layers of fiber reinforcement material 8, such as glass fiber, carbon fiber, and / or aramid fiber. However, it is contemplated that the assembly of reinforcement material 2 can include any number and combination of reinforcement materials suitable for wind turbine blade manufacturing, and may also include, for example, a foam or balsa core, composite structures (e.g., spar caps), sensors, lightning conductors and receptors, heating plates, and root inserts.

[0026] The vacuum bag material 6 is sealed against the upper surface 10 of the mold cavity 4, thereby forming an airtight space 24 around the assembly of reinforcement material 2 (between the vacuum bag material 6 and the upper surface 10 of the mold cavity 4). The outlet line 12 of a vacuum pump (not shown) is connected to the vacuum bag material 6 at an outlet valve, and the inlet line 18 of a reservoir 20 of liquid resin 26 from an acid-cleavable epoxy polymer is connected to the vacuum bag material 6 at an inlet valve. During the resin infusion process, air is drawn from the airtight space 24 through the outlet valve, thereby forming a vacuum around the assembly of reinforcement material 2. Under vacuum, the liquid resin 26 is then drawn into the assembly of reinforcement material 2 through the inlet valve. In some embodiments, a distribution medium (or flow medium) may be laid between the top of the assembly of reinforcement material 2 and the vacuum bag 6 to promote uniform flow of resin in the assembly of reinforcement material 2. Such a distribution medium is typically composed of a high-density polyethylene mesh. Once the assembly of reinforcement materials 2 is fully infiltrated by the liquid resin 26, the resin cures or solidifies to form a matrix material that binds the assembly of reinforcement materials into a consistent, rigid component.

[0027] Typically, liquid resin 26 is a viscous liquid prepolymer system that is configured to be converted into a solid polymer system through a curing process. Liquid resin (or resin system) 26 includes a base resin component and may include a curing agent or hardener that chemically triggers the curing process. Applying heat and / or ultraviolet light to resin system 26 can additionally or alternatively affect curing.

[0028] The epoxy polymer matrix material produced after the liquid resin 26 is cured is a thermoset material. As is well known in the art, thermoset materials are solid polymer systems obtained by irreversible chemical crosslinking of the resin system. Due to the irreversible nature of the chemical crosslinking, known thermoset materials are not easily chemically decomposed and are therefore difficult to process for recycling.

[0029] The epoxy polymer resin system used in the manufacture of articles comprising epoxy polymers described herein is an acid-cleavable epoxy polymer. The acid-cleavable epoxy polymer can be, for example, an epoxy polymer based on an amine-cured epoxy resin, such as Olin Airstone 760, Hexion RIMR 035C infusion epoxy resin, Aditya Birla Recyclamine system.

[0030] The vacuum bag material 6, inlet and outlet valves, inlet and outlet pipelines 12, 18, distribution medium, and any other materials or components used in the resin infusion process that do not constitute the curing component are referred to as auxiliary objects or materials. Some of them are consumables or disposable materials. For example, the vacuum bag material 6, inlet and outlet pipelines 12, 18, and distribution medium are typically made of thermoplastic materials. Such thermoplastic materials include polyethylene, polypropylene, polystyrene, nylon, and some polyesters, such as PET. The inlet and outlet valves can be made of thermoplastic materials and / or metal materials. Other auxiliary objects are intended for various uses, such as tools and molds.

[0031] Tools used to handle or apply epoxy resin in other manufacturing methods are also considered auxiliary items and can be handled according to the methods described. For example, scrapers, brushes, rollers, and buckets are examples of such tools. Another type of auxiliary item is personal protective equipment. Using epoxy resin may require the use of protective equipment such as protective clothing, gloves, safety glasses, and shoes. If such auxiliary items become contaminated with resin during use, they usually must be discarded. Therefore, using the method of the present invention to remove contaminants can increase reuse rates or improve the availability and value of recycled materials.

[0032] It is understandable that, in resin preparation and / or the infusion process, liquid resin 26 can contact these auxiliary objects, and due to the viscosity of resin and common adhesiveness, some resins can adhere to the contact surface.Along with the carrying out of the infusion process, the resin of adhesion may be partially or completely cured on the auxiliary object, thereby cause the auxiliary object to be polluted by the epoxy polymer resin of solidification, uncured and / or partly cured.That is to say, the auxiliary object is polluted by liquid prepolymer resin and / or solid epoxy polymer matrix material.The contaminating epoxy resin system 26 that exists with prepolymer resin and / or matrix material form can be called the pollutant that comprises polymer, oligomer and / or monomer.

[0033] Now go to Figure 2 , which presents a method for treating auxiliary parts contaminated by the aforementioned epoxy polymer liquid resin system 26, in the form of a flow chart. As shown, the first step 28 of the method involves recovering the contaminated auxiliary parts from the resin infusion apparatus after the resin infusion process is complete. The auxiliary parts may be contaminated by cured, uncured, partially cured resin, or a combination thereof.

[0034] Alternatively, the contaminated auxiliary objects can first be mechanically comminuted by cutting or shredding.

[0035] According to the second step 30, the contaminated auxiliary object is exposed to a releasing agent, for example, by rinsing or immersing it in a releasing agent that comprises an acid (such as acetic acid or formic acid). This can cause uncured, partially cured or fully cured epoxy resin to degrade by swelling into swollen epoxy particles or chemically decompose into monomers and / or oligomers, while the auxiliary object is kept intact. The concentration of acetic acid or formic acid in water in the releasing agent is preferably 60% to 90%. The releasing agent softens, disintegrates and / or dissolves in the releasing agent, thereby releasing from the surface of the auxiliary object. That is, the resin is released from the surface of the auxiliary object and forms pollutant byproducts with the releasing agent and optional inert components (such as glass fiber).

[0036] Flushing step 30 can be carried out by contaminated auxiliary object being immersed in the releasing agent groove.Preferably, contaminated auxiliary object is immersed in the releasing agent groove maximum 1 hour, so that the resin structure has enough reaction time to degrade, thereby discharges from the auxiliary object surface.Sufficient reaction times depend on the surface area and volume ratio of the temperature and concentration of releasing agent and pollutant at least usually, and may be longer in many cases, for example maximum 10 hours or maximum 48 hours.Mechanical treatment also can shorten release time.The pollutant by-product that is formed by releasing agent and degraded resin is collected in the groove, can be the mixture or the solution of acid and degraded resin.Additionally or alternatively, the pollutant by-product may comprise solid resin fragment or the epoxy polymer particle of swelling, and they may be deposited in the groove bottom.

[0037] In embodiments where the auxiliary item is a hose or tube (such as inlet and outlet lines), a release agent may be flushed through the hose to further facilitate resin release.

[0038] As shown in step 32, the release agent can be heated before or during rinsing of the auxiliary object to accelerate the release of contaminants. Research has found that using a heated release agent during rinsing is particularly advantageous when the auxiliary object is a thermoplastic. In such embodiments, the increased temperature of the release agent enhances the flexibility of the auxiliary object, further facilitating the mechanical release of contaminants from the auxiliary object surface. Preferably, the release agent is heated to a temperature of approximately 60°C to 90°C.

[0039] Once the resin is released from the auxiliary object, the auxiliary object is removed from the release agent or contaminant byproduct tank and prepared for recycling or reuse, as shown in steps 34 and 36. For example, the auxiliary object can be rinsed with water to remove any remaining contaminant byproducts and dried (e.g., in pressurized gas) for reuse in another resin infusion process. Alternatively, the cleaned auxiliary object can be recycled as a cleaner, higher value and / or more easily recyclable raw material into an appropriate waste stream.

[0040] According to step 38, after the auxiliary objects have been removed from the contaminant byproducts, the contaminants including the degraded resin are extracted from the contaminant byproducts using appropriate separation techniques, such as a combination of one or more of pH adjustment, filtration, separation centrifugation, evaporation, spray drying, and cyclone separators.

[0041] In step 40, the recovered degraded resin is then recycled using known recycling methods. Recycling may involve depolymerization, for example to generate BPA that can be used as a more environmentally friendly source of new epoxy resins. Once the pollutants including the degraded resin have been at least partially removed from the pollutant byproducts, the release agent can be reused (optionally after treatment) in the method for treating the contaminated auxiliary objects, as shown in step 42. When only a portion of the pollutants are extracted from the contaminated byproducts, the reuse of the release agent is found to be particularly advantageous because the reuse of the release agent ensures that the unextracted pollutant portion will not be lost and will eventually be extracted after the subsequent use of the release agent in the method of the present invention. In addition, extracting only a portion of the pollutants is faster and more energy-efficient. When only a portion of the pollutants is extracted, this is equivalent to extracting at least a portion of the pollutants from the pollutant byproducts and then reusing the contaminated byproducts as a release agent. It is possible to consider rinsing multiple auxiliary objects simultaneously in the same tank.

[0042] Those skilled in the art will appreciate that modifications may be made to the above-described specific embodiments without departing from the inventive concept defined in the claims.

Claims

1. A method of treating an auxiliary article used in the manufacture of an article comprising an epoxy polymer, the method comprising: - providing an auxiliary article for use in the manufacture of epoxy polymers, wherein the auxiliary article is contaminated with contaminants including uncured, partially cured and / or fully cured epoxy polymers; - exposing the contaminated auxiliary article to a release agent to release the contaminant from the auxiliary article and form a contaminant byproduct comprising the release agent and the contaminant; - separating the auxiliary objects from the contaminant by-products; Wherein, the epoxy polymer is an acid-cleavable epoxy polymer, and the releasing agent comprises an acid.

2. The method according to claim 1, wherein the releasing agent comprises an organic acid, preferably the releasing agent comprises formic acid and / or acetic acid.

3. The method of claim 1 or 2, wherein the contaminant byproducts comprise swollen epoxy particles.

4. A method according to any one of the preceding claims, wherein the epoxy polymer is based on an amine-cured epoxy resin.

5. The method according to any one of the preceding claims, further comprising recycling or reusing the auxiliary item.

6. The method of any one of the preceding claims, further comprising extracting the pollutants from the pollutant byproducts and recycling the pollutants, preferably recycling the pollutants comprises depolymerizing the pollutants.

7. The method of any one of the preceding claims, further comprising reusing the contaminated by-product as a releasing agent after extracting at least some of the contaminants from the contaminant by-product.

8. The method of any one of the preceding claims, wherein the contaminant comprises an inert component and the inert component is released from the auxiliary object into the contaminant byproduct, preferably the inert component is a non-swellable polymer component, a metal component, a fiber component or a particulate component.

9. The method according to any one of the preceding claims, wherein the release agent further comprises an organic solvent, a surfactant, a colorant and / or a salt.

10. The method of any preceding claim, wherein the contaminant comprises uncured and / or partially cured epoxy polymer, the method further comprising curing the epoxy polymer prior to exposing the contaminated auxiliary article to the release agent.

11. The method according to any one of the preceding claims, wherein exposing the contaminated auxiliary article to the release agent comprises spraying, immersing and / or rinsing the auxiliary article in or with the release agent.

12. The method of any preceding claim, further comprising heating the release agent before or during exposure of the auxiliary article to the release agent.

13. The method according to any one of the preceding claims, further comprising mechanically treating the contaminated auxiliary article.

14. The method according to any of the preceding claims, further comprising mechanically treating the contaminated auxiliary article during and / or after exposing the contaminated auxiliary article to the release agent.

15. A method according to any preceding claim, wherein the auxiliary article comprises a thermoplastic polymer.

16. A method according to any preceding claim, wherein the auxiliary items comprise one or more of a vacuum bag, a tube or hose, a valve, a tool, personal protective equipment and / or a mould.

17. The method of any preceding claim, wherein the auxiliary article comprises a confined space and the confined space is contaminated with a contaminant, wherein the method further comprises mechanically removing at least some of the contaminant from the confined space before or during exposing the contaminated auxiliary article to the release agent.

18. The method according to any of the preceding claims, wherein the auxiliary article is an auxiliary article used in the manufacture of wind turbine blades.

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