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EP-4741131-A2 - CORE MATERIAL OBTAINED FROM WASTE POWDER OF THERMOPLASTIC FOAMS AND SANDWICH COMPOSITE PARTS CONTAINING THIS MATERIAL

EP4741131A2EP 4741131 A2EP4741131 A2EP 4741131A2EP-4741131-A2

Abstract

The disclosure relates to obtaining core material by mixing waste powders generated during the processing of thermoplastic foams with a binder and preferably fiber additive and compressing them in a mold, and to sandwich composite parts using this material. The core material of the disclosure has been developed especially for the production of sandwich composite structures with complex shapes, indented, angled, angular and circular surfaces.

Inventors

  • BA ER, Gülnur
  • KABACA, Rümeysa Zeynep

Assignees

  • Telateks Tekstil Ürünleri Sanayi ve Ticaret Anonim Sirketi

Dates

Publication Date
20260513
Application Date
20250922

Claims (14)

  1. A core material with complex shapes to be used in sandwich composite parts for industries such as automotive, aviation, construction, maritime and energy sectors, characterized by comprising; waste powders released during the processing of thermoplastic foams and binder resin.
  2. The core material according to claim 1, characterized by comprising; at least one thermoplastic foam waste powder selected from polyurethane (PU), polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polyvinyl chloride (PVC) and polycarbonate (PC).
  3. The core material according to claim 1, characterized by comprising; at least one binder resin selected from polyester, vinylester, epoxy, polyurethane and acrylic based resins is used.
  4. The core material according to claim 1, characterized by comprising; at least one binder resin selected from copolyester, copolyamide, polyurethane, polyethylene, polypropylene, epoxy-based thermoplastic resins.
  5. The core material according to claim 1, characterized by comprising; a fiber additive as reinforcement material.
  6. The core material according to claim 5, characterized by comprising; at least one fiber additive selected from glass, carbon and aramid fiber types in different sizes and shapes.
  7. The core material according to claim 1, characterized by comprising; at least one connection opening and/or connection element.
  8. A production method of core material with complex shapes to be used in sandwich composite parts for industries such as automotive, aviation, construction, maritime and energy sectors, characterized by comprising the process steps of; (i) Mixing of waste powders generated during the processing of thermoplastic foams with binder resin and preferably fiber additives (ii) shaping the mixture in a mold using a compression method to create the desired complex shapes under specified temperature and pressure.
  9. The production method according to claim 8, characterized in that; in the process step (i), at least one thermoplastic foam waste powder selected from polyurethane (PU), polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polyvinyl chloride (PVC) and polycarbonate (PC) is used.
  10. The production method according to claim 8, characterized in that; in the process step (i), at least one binder resin selected from polyester, vinylester, epoxy, polyurethane and acrylic based resins is used.
  11. The production method according to claim 8, characterized by comprising; in the process step (i), at least one binder resin selected from copolyester, copolyamide, polyurethane, polyethylene, polypropylene and epoxy-based thermoplastic resins.
  12. The production method according to claim 8, characterized in that; in the process step (i), at least one fiber additive selected from glass, carbon and aramid fiber types in different sizes and shapes is used.
  13. The production method according to claim 8, characterized in that; in the process step (ii), it is molded at temperatures and pressures reaching 150 MPa and 150°C.
  14. A sandwich composite part comprising the core material according to any of the preceeding claims.

Description

Field of the Invention The invention relates to core material made of synthetic foam and sandwich composite parts containing this material. The invention particularly relates to obtaining core material by mixing waste powders generated during the processing of thermoplastic foams with a binder and compressing them in a mold, and obtaining sandwich composite parts from this material. The core material of the present invention has been developed especially for the production of sandwich composite structures with complex shapes, indented, angled, angular and circular surfaces. State of the Art Sandwich-shaped fiber-reinforced polymeric composites have the potential for use in many areas of industry such as automotive, aviation, construction, marine and energy sectors. It is used in many special areas, especially in the automotive industry where durability, lightness and insulation are required, as an insulating and robust sheet in the body of cold chain transport vehicles, as an insulating material in structures in the construction industry, as structural parts of surface vehicles in maritime applications and in the production of blades in wind turbines. Fiber-reinforced polymeric composite sandwich structures are structural elements consisting of a lightweight core material sandwiched between two thin, rigid surface layers. This structure offers a high strength-to-weight ratio and is widely used in different engineering applications. Surface layers are usually made of polymeric matrices reinforced with high-strength fibers such as carbon fiber, glass fiber, or aramid fiber. Thermoset resins such as polyester, vinylester, epoxy or polyurethane are generally used as matrix materials. Surface layers provide high strength, hardness and surface durability to the structure. The core material increases the lightness and thickness of the sandwich structure while also providing impact resistance, energy absorption and insulation properties. Common core materials include polymeric foams (e.g., PVC, PET, PU foams), honeycomb structures (e.g., aluminum, Nomex, polypropylene honeycomb), and balsa wood. Sandwich materials traditionally used in the composites industry are usually made from core materials such as honeycomb or foam. However, existing core materials generally have a rectangular block structure with a flat surface and do not allow the production of parts with complex shapes, angles, or circular surfaces. The desired complex shape is achieved by applying processes such as cutting, carving, sanding and drilling using the machining method. The amount of waste from the blocks during machining is high and the waste is in the form of waste. These wastes cause serious environmental problems. For this reason, studies on the re-evaluation of waste foams are ongoing. For example, in the patent application numbered TR2019/19979, the production of an insulation material from waste EPS is described. It is stated that waste EPS can be ground and dissolved in acetone, dissolved in a certain amount of acetone by continuous mixing, and then selected materials can be added and dried in the form of sheets at 50-80°C to obtain insulation material. Ho wever, the materials added to the waste foam are not disclosed in the relevant material, and the resulting product is not intended for use as a sandwich composite core, but is in the form of a sheet for use in the construction industry. As a result, due to the above-mentioned disadvantages and the inadequacy of the existing solutions, a development is required to be made in the relevant technical field. Purpose of the Invention The invention aims to solve the above-mentioned negativities and it is inspired by the current situation The main purpose of the invention is to convert the waste powders generated during the machining of foam-shaped core materials used in the state of the art into a core material again by pressing and compression method after mixing them homogeneously with a binding resin. This core material is used in sandwich composite parts to both reduce weight and provide the necessary structural strength. During the compression process, this material takes the shape of complex-shaped molds, making it possible to produce complex-shaped sandwich composite structures. In addition, the durability of the core material can be increased by adding additives such as chopped glass fiber (length 2-5 mm) into the powder and resin mixture. With this invention, environmental damage is prevented by recycling the waste produced. In order to fulfil the above-mentioned purposes, the invention is a core material that can be in complex shapes to be used in sandwich composite parts for industries such as automotive, aviation, construction, maritime and energy sectors, comprising; waste powders released during the processing of thermoplastic foams and binder resin. In order to fulfil the above-mentioned purposes, the invention is a method for producing the said core material, comprising the f