Maro Publications

Polyester Coatings


from 3/25/2013

Maro Encyclopedia


Patent Abstracts

Patent Titles





“Solid polyester granules or beads are used as matting agents in paints, especially flat paints, to provide increased mar and burnish resistance. When included in flat paints, they provide outstanding resistance to wet and dry abrasion. The granules are generally added to paint formulations in the form of a dispersion in a continuous aqueous phase. In some cases the polymer granules contain a pigment, such as titanium dioxide, and in other cases they are unpigmented.

In the formulation of conventional flat decorative paints, the largest of the granules are approximately the thickness in diameter of the paint film. They protrude through the surface of the film and act as stationary ball bearings. Clothing, cleaning cloths and other objects that would normally mar the film only come into contact with the granules, and hence the paint film is very burnish resistant. This is in marked contrast to conventional flat paint films, where abrasion produces a large and unsightly localised increase in gloss.

Such solid polyester granules are commonly manufactured by the copolymerisation of an unsaturated polyester and styrene in a suspension polymerisation process. For example, solid polyester granules are often produced by first emulsifying in water a solution of unsaturated polyester in styrene which contains low levels of benzoyl peroxide and azobis(isobutyronitrile). Emulsification is achieved through use of colloid stabilisers and shear stirring the solution until a desired droplet size has been obtained. When this has been achieved, a low level of N,N-diethylaniline is typically added to the reaction solution to complete the redox couple (with benzoyl peroxide) and initiate the polymerisation reaction. The azobis(isobutyronitrile) thermal initiator assists in the latter part of the exotherm to increase conversion, but has been found to be not particularly effective at this. The reaction may or may not be stirred during this stage, but stirring has traditionally been maintained to prevent any risk of settlement of the newly formed granules.”

[Such et al, US Patent 8,389,645 (3/5/2013)]


Bookmark this page to follow future developments!.
(RDC 6/5/2012)


Roger D. Corneliussen

Maro Polymer Links
Tel: 610 363 9920
Fax: 610 363 9921


Copyright 2013 by Roger D. Corneliussen.
No part of this transmission is to be duplicated in any manner or forwarded by electronic mail without the express written permission of Roger D. Corneliussen

* Date of latest addition; date of first entry is 3/25/2013.