Oil Varnish Research Articles

Rheological characteristics of pigment dispersions: Flow behaviour under steady shear flow

The rheological characteristics under steady shear flow of dispersions of pigment in a mid-litho oil varnish have been examined. Using a Weissenberg rheogonio-meter the influence of pigment concentration and dispersion temperature on flow behaviour have been examined in some detail. Data have been examined in terms of the initial peak stresses and of the equilibrium stresses encountered. By taking the ratio of these two as a measure of thixotropy it would appear that thixotropy goes through a maximum with increasing pigment concentration. The results also indicate that particle/particle interaction controls flow up to the point at which a peak stress occurs. Thereafter the flocculation/deflocculation process predominates.

Ionic conduction in polymer films. III Influence of temperature on water absorption

AbstractThe variation of water absorption with temperature of three varnish films, a pentaerythritol alkyd, an epoxy‐polyamide and a phenol‐formaldehyde tung oil, has been measured. In the case of the first two, minima were observed the temperatures of which corresponded to glass transition temperatures of the polymers. In contrast, films of the phenol‐formaldehyde tung oil varnish showed neither a minimum in the water absorption‐temperature curve nor a glass transition temperature over the range 5–34°C. Further work is necessary to establish whether this relationship has general application.

The aging of some pigmented polymeric films

Pigmented films based on different polymers and their blends have been prepared on pine-wood and low-carbon steel substrates, and exposed in laboratory and out-of-doors. In the high humidity cabinet, films based on pentaerythritol alkyd modified with 65% linseed oil and applied to a pine-wood surface, deteriorated by blistering, except those pigmented with titanium dioxide. A blend of the same medium with stabilized chlorinated rubber showed good resistance to degradation in high humidity conditions as well as in marine and industrial environments. In the latter system, especially the combined pigmentations zinc oxide/rutile behaved very well on aging. However, in linseed oil varnish, the combined pigmentation zinc oxide/rutile/basic lead carbonate protected the exposed films very well. The rutile modification of titanium dioxide protects a polymeric film by absorbing ultraviolet light which would otherwise damage it. Also, zinc oxide indicates complete absorption of the shorter wavelengths, and basic lead carbonate transmits much more ultraviolet light. Nevertheless, lead and zinc soap formation with free acids might affect various film properties in the above pigment combination. The highest retention of whiteness was exhibited by the film samples exposed to a marine environment, and the lowest by those exposed to an industrial atmosphere.

ビニル化油性塗料の研究 (第1報)

ビニル化油性塗料の研究 (第1報)

ビニル化油性塗料の研究 (第2報)

ビニル化油性塗料の研究 (第2報)

Drying Oil and Oleoresinous Varnish Films.Increase In Acidity on Aging

Drying Oil and Oleoresinous Varnish Films.Increase In Acidity on Aging

The determination of volatile thinner in oil varnish

The determination of volatile thinner in oil varnish