Page 58 - Handbook of Surface Improvement and Modification

4

Surface Matting (Flattening)

4.1 METHODS AND MECHANISMS OF FLATTENING

The mechanism of flattening is similar to the mecha-
nism of glossiness. The surface finish of a material
depends on how the smooth or rough surface is. The
roughness of surface correlates with light reflection
and gives the perception of surface condition. Cus-
tomers of products discussed in the previous chapter
had a preference for a glossy finish but many prod-
ucts required a matte finish, such as coatings, coil
coatings, cosmetics, flooring, leather, paints, powder
coatings, printing inks, and wood.
A typical method of varying surface gloss
includes a variation of proportion between binder
and filler. The more binder the higher the gloss of
the material. Materials are usually divided into flat
(less than 10% reflection), low sheen, eggshell, semi
glossy, and glossy (more than 70% reflection). The
glossy material has usually purely organic composi-
tion. The flat material has substantial part of the sur-
face made out of flattening additive. The flattening
additives can be either organic or inorganic. In the
case of organic additives, a very fine, uniform sur-
face texture can be produced in a reproducible man-
ner. Such surface also provides a soft-feel effect.
Figure 4.1 shows that, depending on the composition
and the amount of fillers, a material can be made
Figure 4.1. SEM image of different glazes. transparent, opaque, and opaque and matte. It is
1: zirconia-based opaque glaze, 2: calcium more challenging to obtain both transparent and
and zinc-based matte glaze, 3: titania-based
opaque glaze, and 4 transparent glaze. matte material. The use of inorganic additives
[Adapted, by permission, from Sheikhattar, improves in addition abrasion, anti-scratch, and mar
M; Attar, H; Sharafi, S; Carty, WM, Mater. resistance. In the next section, six types of matting
Charact., 118, 570-4, 2016.
additives (wax, polymeric wax, polycondensate,
polyurethane beads, silicon dioxide, and wax-modified silicon dioxide) are discussed.