Thermal desizing or caramelising

At 400°C, glass and silicate fabrics at a width of maximum 1850 mm can caramelised/thermally desized. Depending on the type of the size being used during weaving process, the fabric receives a beige to brown colour after caramelising.

The advantages of caramelising/ thermal desizing of glass and silicate fabrics can be summarised as follows:

  • Better adhesion of the desized fabric with other substrates such as different coating media, impregnations or

  • Better adhesion of the desized fabric with laminates, foils

  • Through reduction (thermal combustion) of the size on the greige fabric, the production of smoke is also reduced if this thermally desized fabric is later exposed to high temperatures


A disadvantage of this treatment is the reduction of the tear strength as against untreated greige fabrics. For this reason we do not completely thermally desize the greige fabric in order to maintain the best possible tear strength of the fabric.

The beige-caramel colour, which is typical following thermal desizing (this is why this treatment is often known as caramelising), cannot later be covered up by colouring through impregnation or coating with all colours.

Another option when using our thermal desizing is, for example, to sinter out PTFE coated or impregnated glass and silicate fabrics.