Method for inhibiting the formation and deposition of silica scale in water systems

DETAILED DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENTS This invention specifically relates to the use of a polyamide composition for inhibiting the formation and deposition of silica and silicate compounds in water systems.
The water-soluble polyamides of this invention are formed from condensation polymerization of at least one or more carboxylic acids, esters, acid halides or anhydrides with one or more polyamines.
As used herein, "polyamine" means a compound of formula H.
sub.
2 N--L--NH.
sub.
2 where L is any combination of linear, cyclic or branched C.
sub.
2 -C.
sub.
8 alkylene groups, aromatic groups, polycyclic groups and heteroclic groups, where at least one of the alkylene, aromatic, polycyclic and heteroclic groups are connected through NH or O.
The polyamide of this invention consists of repeating groups of formula ##STR2## where R.
sub.
1 and L are defined herein and n is an integer such that the molecular weight of the polyamide is at least 500.
In another preferred embodiment, the polyamides are prepared by condensing one or more carboxylic acids, acid halides, esters or anhydrides with one or more polyamines and an epoxy resin.
In another preferred embodiment, the condensation polymer is prepared by condensing one or more carboxylic acids, acid halides, esters or anhydrides with one or more polyamines and the reaction product of an epoxy resin with one or more polyamines.
The epoxy resin compounds suitable for use in preparing the polymeric condensation products of this invention are organic compounds having at least two reactive epoxy groups.
These compounds can contain substituent groups such as alkyl, aryl, organic ester, phosphate ester, halogen, cyano group among others without interfering with the condensation.
The epoxy resin compounds may also have olefinic unsaturation on substituents.
The preferred epoxy resin compounds are the aryl or alkyl substituted compounds having as the sole reactive group under the conditions of the reaction, at least two epoxy groups and wherein oxygen is present only in oxirane, ether and ester arrangement