PHENODUR® PR 263/70B

Phenodur PR 263 is specially developed as binder for shop- and washprimers. Phenodur PR 263 differs from Beckopox EM 460, wich has been developed for the same purpose, in being faster drying and less yellowing resistant.

Corrosion protection

Phenodur PR 263 is preferably used to formulate wash- and shopprimer in combination with polyvinylbutyral. The ratio between Phenodur PR 263 and PVB is usual between 25 : 75 and 50 : 50 (solid on solid). Such washprimer can be formulated as 1- or 2-component systems. Because of its low viscosity and good pigment wetting properties, Phenodur PR 263 imparts good hiding and filling power. Primers based on Phenodur PR 263 show excellent water resistance and corrosion protection.

Benzene, fuel and oilresistant coatings

Phenodur PR 263 is a suitable solebinder (with the addition of 3 - 5 % phosphoric acid (85 %) for clear or pigmented coatings on rigid substrates. Such coatings show after a few days of air-drying a good resistance against fuels, benzene and oils. This coating material can be forced dried too (e.g. 30 min/100 °C) and plastified through the additon of approx. 20 - 30 % polyvinylbutyral, (calculated on solid resin).

Pigmentation

Phenodur PR 263 has excellent pigment wetting properties and is used preferably as grinding medium to which the polyvinylbutyral is added after the pigment wetting process. Zincphosphates and chromates are partly included in the chemical reaction of the wash primer`s curing process, thereby improving the quality to the primer with regard to weather resistance. Any other extenders and pigments employed should be resistant to phosphoric acid.

Stoving conditions

Depending on the form of use and required coating thickness, the stoving conditions are between 30 and 10 minutes at 180 - 220 °C. The upper temperature limit where overstoving begins to occur and flexibilty accordingly starts to decline is 220 °C. For thin film such as can coatings, conditions of 10 - 15 min/190 - 200 °C are adequate, or 90 s/265 °C (shock curing). Good resistance to chemicals is obtained as from 190 °C onwards.

Acid catalysis

a) One pack system: about 5 % phosphoric acid (85 %), calculated on total binders (solid);

b) Two-pack systems: about 5 - 10 % phosphoric acid (85 %), calculated on total binders (solid).

An excess of more than 10 % phosphoric acid may promote subcoating rust development. To avoid the processing difficulties that may occur when the paint formulation is mixed with phosphoric acid it has been found useful to dilute the acid in advance with n-butanol in a ratio of about 3 : 1. Since Phenodur PR 263 is severely discolored by dissolved metall ions, especially those of iron, it is advisable to use iron free phosphoric acid (85 %).

The importation, processing or use of this product in the United States of America is subject to a Significant New Use Rule (SNUR) issued by the U.S. Environmental Protection Agency (US EPA). Among other conditions, the SNUR prohibits the predictable or purposeful release of the product to waters of the U.S. from manufacturing, processing or uses and imposes certain notice and recordkeeping requirements. Please see 40 CFR 721.5905 [or 40 CFR 721.5908 as applicable] for further information. This product may also be subject to export notification under TSCA Sec. 12(b).

At temperatures up to 25 °C storage stability packed in original containers amounts to at least 365 days.