Heating Nonwoven Mat

Applicant(s): TWE Meulebeke
Inventor(s): Dany Michiels [BE]; Amine Chaouech [BE]
Patent number: WO2025233388A1
Publication date: 2025-11-13
Field: Flexible heating materials

The invention relates to flexible heating materials incorporating a nonwoven layer, with potential additional functionality as an acoustic barrier.

Flexible heating materials are known for applications such as underfloor heating, wall coverings, automotive, and healthcare.
Existing solutions typically use conductive fibres within nonwovens, with electrodes placed on the surface.

Problems with Prior Art

• Poor connectivity between conductive fibres and electrodes
• Use of adhesives further reduces conductivity
• Oxidation of metallic fibres leads to long-term conductivity loss

Therefore, a nonwoven-based heating material without conductive fibres, while maintaining flexibility, durability, and conductivity, was developed.

The invention introduces a nonwoven layer without conductive fibres, where conductivity is provided by a conductive coating paste applied to the surface.

Key Features

• Conductive paste composition:
  • 0.5–20 wt% allotropic carbon particles
  • 0.5–20 wt% polyurethane
  • Water
• Paste is applied and dried to form a conductive film
• Electrodes are fixed directly to the conductive layer

This approach eliminates fibre–electrode connectivity issues and oxidation problems.

Example – Preparation of a Coating Paste

• Paste prepared in two steps
• First step: pre-dispersion of carbon particles
• Final composition (dry content 12.5 wt%):
  • 7 wt% polyurethane
  • 4.9 wt% carbon particles
  • 0.6 wt% additives
• Viscosity: 22,000 mPa·s

• No conductive fibres → no oxidation or connectivity loss
• Stable, flexible, and durable conductive film
• Improved thermal and aging resistance
• Thin surface coating ensures good conductivity
• Simplified manufacturing and flexible electrode fixation
• Compatible with various voltages, including solar panels and batteries
• Suitable for a wide range of applications and power outputs