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EP-4739480-A1 - METHOD FOR MANUFACTURING A MOLDED STRUCTURE

EP4739480A1EP 4739480 A1EP4739480 A1EP 4739480A1EP-4739480-A1

Abstract

Method for manufacturing a molded structure (2), the method comprising: a) cutting one or more fibre-reinforced composite structures (20) into a plurality of smaller pieces (12) comprising glass fibre-reinforced composite material; b) filling the smaller pieces (12) and a binder material (10) into a mold (4) having an inner space (16); c) providing a pressure (P) during a predefined curing time (Δt c ) 10 towards the smaller pieces (12) in the inner space (16) of the mold (4); d) removing the molded structure (2) from the mold (4); e) the mold (4) and hereby the smaller pieces (12) and the binder material (10) are vibrated in a predefined period of time (T) and f) while temperature of the mold (4) is maintained in a temperature range of 40-90°C.

Inventors

  • RYTTER, FREDERIK

Assignees

  • Leicon ApS

Dates

Publication Date
20260513
Application Date
20240704

Claims (17)

  1. 1. Method for manufacturing a molded structure (2), the method comprising: a) cutting one or more fibre- reinforced composite structures (20) into a plurality of smaller pieces (12) comprising glass fibre-reinforced composite material; b) filling the smaller pieces (12) and a binder material (10) into a mold (4) having an inner space (16); c) providing a pressure (P) during a predefined curing time (At c ) towards the smaller pieces (12) in the inner space (16) of the mold (4); d) removing the molded structure (2) from the mold (4), wherein: e) the mold (4) and hereby the smaller pieces (12) and the binder material (10) are vibrated in a predefined period of time (T) and f) while temperature of the mold (4) is maintained in a temperature range of 40-90°C, wherein the smaller pieces (12) are shorter than 20 cm.
  2. 2. Method according to claim 1, wherein the smaller pieces (12) are vibrated with a frequency in the range 5-45 Hz.
  3. 3. Method according to claim 1 or 2, wherein the curing time (At c ) is in the range 1-30 minutes.
  4. 4. Method according to one of the preceding claims, wherein the method comprises a shaping process, wherein after removing the molded structure (2) from the mold (4) the molded structure (2) is put into another differently shaped mold (104) before the molded structure (2) is cured, wherein the molded structure (2) is shaped into another shape and cured while being in the differently shaped mold (104).
  5. 5. Method according to one of the preceding claims, wherein the binder material (10) constitutes 10-30% of the mass of the smaller pieces (12).
  6. 6. Method according to one of the preceding claims, wherein the binder material (10) constitutes at least 20% of the mass of the smaller pieces (12).
  7. 7. Method according to one of the preceding claims, wherein the pressure (P) per area unit is in the range 10-200 MPa, 15-150 MPa or 20-100 MPa.
  8. 8. Method according to one of the preceding claims, wherein the method comprises: - selecting the smaller pieces (12) in such a manner that the length of the smaller pieces (12) has a mean (|ii) in the range 5-15 cm and the standard deviation (ci) of the smaller pieces (12) is in the range 5-10 cm.
  9. 9. Method according to one of the preceding claims, wherein the mold (4) is an extruder mold (4) comprising: - a extruder outlet channel (30); - a main body (32) provided with an inlet (34) and - a pressurising unit (36) arranged and configured to provide a pressure towards material filled into the main body (32).
  10. 10. Method according to one of the preceding claims, wherein the method comprises vibrating the smaller pieces (12) while providing the pressure (P).
  11. 11. Method according to one of the preceding claims, comprising adding additional glass fibers into the mold (4) in order to increase the strength of the molded structure (2).
  12. 12. Method according to one of the preceding claims, wherein the method comprises: - determining the mechanical properties of the smaller pieces (12) prior to molding the molded structure (2), wherein the wall thicknesses of the molded structure (2) are selected in such a manner that the mechanical strength of the molded structure (2) is equal to or above a predefined selected level.
  13. 13. Method according to claim 12, wherein the wall thicknesses of the molded structure (2) are selected to be at least 6 mm.
  14. 14. Method according to one of the preceding claims, wherein the method comprises: - after cutting one or more fibre- reinforced composite structures (20) into a plurality of smaller pieces (12) comprising glass fibre- reinforced composite material, determining the directions of the glass fibres of smaller pieces (12); - before filling the smaller pieces (12) and a binder material (10) into the mold (4), determining the expected mechanical strength of the molded structure (2) to be moulded in dependency of the orientation of the of the directions of the smaller pieces (12) and - arranging the smaller pieces (12) in the mold (4) in order to maximize the expected mechanical strength of the molded structure (2) to be moulded.
  15. 15. Method according to one of the preceding claims, wherein the method comprises: - b) filling new fibres (42) into the mold (4) together with the smaller pieces (12) and the binder material (10).
  16. 16. Method according to claim 15, wherein the method comprises: - after cutting one or more fibre- reinforced composite structures (20) into a plurality of smaller pieces (12) comprising glass fibre- reinforced composite material, determining the directions of the new fibres (42); - before filling the smaller pieces (12) and a binder material (10) into the mold (4), determining the expected mechanical strength of the molded structure (2) to be moulded in dependency of the orientation of the of the directions of the smaller pieces (12) and the directions of the new fibres (42) and - arranging the smaller pieces (12) and the new fibres (42) in the mold (4) in order to maximize the expected mechanical strength of the molded structure (2) to be moulded.
  17. 17. Molded structure (2) manufactured by using a method according to one of the preceding claims.

Description

Method for Manufacturing a Molded Structure Field of invention The present invention relates to a method for manufacturing a molded structure comprising glass fibre recycled from fibre-reinforced composite structures. Prior art According to the European wind energy agency, around 14,000 blades could be dismantled across the continent in the next five years, which would amount to between 40,000 and 60,000 tonnes of waste. For this reason, recycling, especially of wind turbine blades, is seen as one of the key challenges for the industry. The wind energy sector is experiencing tremendous growth due to the global need for a cleaner energy supply. The useful life of a wind turbine is around 25-30 years, depending on the level of maintenance. Most of its components are recyclable, although the challenge lies in recycling the wind blades efficiently. The materials from which they are made are mostly composites, such as fibreglass, carbon fibre or various resins, so separating them for recycling is particularly difficult and expensive. Due to the speed at which wind energy is growing, it is necessary to develop other alternatives as the volume of retired blades will increase rapidly. There are currently three main types of recycling applicable to wind blade components: - mechanical recycling involving shredding following a separation process. The materials are reused, often as filler material, mainly in building materials or plastics; - thermal recycling, in which the blades are incinerated, producing energy and decomposing the composites. This process is able to preserve certain characteristics of the fibrous materials, making them suitable for later use; - chemical recycling applying techniques such as fluidised bed or solvolysis, by means of solvents and thermal processes, separate the resins from the fibres so that both materials can be reused. CN114619613A discloses a metode for recycling waste wind turbine blades. The method comprises the following steps: mixing a waste wind power blade material and a thermoplastic material in a preset size range to obtain a molded material; and carrying out compression molding on the molded material to obtain a wind power matching product. The moulded structures produced by using this solution typically have pour mechanical properties due to a high content of air bubbles. Accordingly, it would be desirable to have an alternative method capable of solving this problem. Thus, there is a need for an alternative method for manufacturing a floating foundation for wind turbines, which method reduces or even eliminates the above-mentioned disadvantages of the prior art. There is, however, a need for a method that enables an improved, simpler and more efficient way of reusing fibre-reinforced composite structures such as wind turbine blades. It is an object of the invention to provide a method by which it is possible to recycle fibre- reinforced composite structures and manufacture molded structures that can be used in various constructions. Summary of the invention The object of the present invention can be achieved by a method as defined in claim 1 and by a moulded structure as defined in claim 14. Preferred embodiments are defined in the dependent subclaims, explained in the following description and illustrated in the accompanying drawings. The method according to the invention is a method for manufacturing a molded structure, the method comprising: a) cutting one or more fibre-reinforced composite structures into a plurality of smaller pieces comprising glass fibre- reinforced composite material; b) filling the smaller pieces and a binder material into a mold having an inner space; c) providing a pressure during a predefined curing time towards the smaller pieces in the inner space of the mold; d) removing the molded structure from the mold, wherein e) the mold and hereby the smaller pieces and the binder material are vibrated in a predefined period of time and f) while temperature of the mold is maintained in a temperature range of 40-90°C, wherein the smaller pieces are shorter than 20 cm. Hereby, it is possible to recycle fibre- reinforced composite structures and manufacture molded structures that can be used in various constructions. Cutting one or more fibre-reinforced composite structures into a plurality of smaller pieces comprising glass fibre- reinforced composite material makes it possible to reuse the smaller pieces in a new molded structure. Accordingly, the smaller pieces and the binder material can be filed into a mold having an inner space. In an embodiment, the binding material is spray on the smaller pieces. In an embodiment, the binding material and the smaller pieces are mixed through a stirring process. In an embodiment, the binding material and the smaller pieces are mixed while maintaining the temperature in the range 10-40°C. In an embodiment, the method comprises the step of preheating the mold. In an embodiment, the method comprises the step of