Modified epoxy resin can be processed like thermoplastic

  • Novel thermoset matrix system with thermoplastic properties
  • A.S.SET (Adjustable Simple Thermoset): available as powder and sheet
  • Presentation at upcoming Composites Europe 2014: #composites14

In collaboration with the Polish material manufacturer New Era Materials (NEM), engineers of the Lightweight Design Centre Saxony (LZS GmbH) have developed two new processing technologies that have the potential to dramatically change the way highly-filled thermoset components are produced. Basis are modified epoxy resins that feature thermoplastic processing properties. This allow the production of high-performance components using simple machine and process technology at extremely short cycle times. LZS GmbH will present the material and process, sold under the brand name „A.S.SET“, at the upcoming Composites Europe 2014.

A.S.SET (Adjustable Simple Thermoset)

The modified resins are processed either into powder (A.S.SET-POWDER) or board-shaped semi-finished products with continuous fiber reinforcement (A.S.SET-SHEETS). The brand name A.S.SET (Adjustable Simple Thermoset) stands for the major advantages of the new product such as variable characteristics and ease of processing.

Heated resin impregnates textile preform by simple pressing technology

The A.S.SET-POWDER is the starting material for the newly developed Resin Powder Molding (RPM). Here, a powdery resin is applied onto a textile preform by standard spraying or screening technology. By supplying heat, the powder melts and the preform can be impregnated using a simple pressing technology. A further temperature increase leads to a quick curing of the resin. The RPM process does not need any complicated dosing or injection equipment that is usually required when processing reactive resins. Also the cooling of the semi-finished products and raw materials, which is required for many thermosets, can be omitted.

Reshaping allows production of  complex parts

The A.S.SET-SHEETS are processed in the so-called Thermoset Sheet Forming (TSF) process. By supplying heat, the semifinished products do melt and become thermoformable (similar to thermoplastic organic sheets). With further temperature increase, the sheets cure and obtain very good mechanical and thermal properties. The interesting fact here is that the sheets, as long as they are not crosslinked, can be reshaped. This enables the TSF process to be applied in multiple stages in order to produce particularly complex parts.

In generaal, the RPM and TSF processes are very flexible in terms of material and process control: a wide range of different epoxy resin matrix systems and reinforcement materials can be used to obtain specific mechanical, thermal and chemical properties. Modifications can be realized by blending the RPM powder with color pigments, fire inhibitors or internal release agents. The processing window, in regards to softening or cross-linking temperature, can also be adjusted. Shorter cycle times as well as the possibility to operate the molds at constant temperature further increases the efficiency of the process.

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