This invention relates to a curing agent for powder coating compositions based on epoxy resin binders, the agent being obtained by neutralization of a polycarboxylic acid.
There is a great need for powder-type varnishes for the production of matte coatings, especially in the field of industrial varnishes. The reasons for this are predominantly of a practical kind. Textured and/or matte surfaces require far less cleaning than glossy surfaces. Moreover, it is necessary for reasons of safety to avoid strongly reflective surfaces.
In order to attain the desired effect, a number of measures have become known. For producing matte coatings based on epoxy resins as the binders, the use of special curing agents has proven to be an advantageous mode of operation (see German Pat. No. 2,324,696 which disclosure is being incorporated by reference herein). One disadvantage of the process described therein resides in relatively high curing temperatures (180.degree.-210.degree.C.) when used under practical conditions.
USPTO Backgrounds
USPTO Backgrounds