This invention pertains to ammonium polyphosphates and more particularly to ammonium polyphosphates which are substantially water-insoluble, to processes for preparing the same and to compositions containing the same.
There are a variety of so-called fire-retardant paints on the market, most of which are intumescent and contain phosphate compounds, such as monoammonium orthophosphate, as a fire-retardant additive. None, however, compare favorably with high-quality standard paint formulations in washability, color versatility, ease of application and storage-stability. In addition, the fire-retardant properties of these paints deteriorate with age after being applied due to the effects of weather and humidity on the relatively Water-soluble phosphate. In general, in order to gain widespread acceptance as a fire-retardant additive for use in paints, the phosphate compound should preferably be a non-deliquescent, water-insoluble, solid containing a high phosphorous content and exhibit compatibility with other additives in paint formulations. As can be appreciated, therefore, an ammoniumphosphate compound which is relatively water-insoluble and which meets the foregoing properties for a preferred fire-retardant additive in paint formulations would be an advancement in this art.
Therefore, it is an object of this invention to provide new and useful ammoniumpolyphosphates which are substantially water-insoluble and which are useful as fire-retardant additives in paint formulations, particularly waterbased paint formulations.
It is a still further object of this invention to provide paint compositions, particularly water-based paint compositions, containing ammonium polyphosphates which are substantially water-insoluble, said compositions exhibiting fire-retardant properties.
These and other objects will become apparent from the following detailed description.
The term ammoniacal nitrogen refers to that nitrogen which is present in the form of ammonium ions and is capable of being removed by the hydrogen form of a strong cation exchange resin, i.e., the hydrogen form of a sulfonate polystyrene resin. The term non-ammoniacal nitrogen or nuclear nitrogen refers to nitrogen incap able of being removed in the manner of true ammonium nitrogen.