Process for preventing polymer scale using an alkaline solution of a condensation product of an aromatic compound having at least two amino groups and an aromatic bisester anhydride

A process of producing a polymer of a monomer having an ethylenically unsaturated double bond, which comprises polymerizing the monomer in a polymerization vessel having a polymer scale preventive coating on its inner wall surfaces, whereby polymer scale is prevented from being deposited,

• wherein said polymer scale preventive coating has been formed by applying, as polymer scale preventive agent, an alkaline solution with a pH of 7.5 to 13.5, consisting essentially of a condensation product of:
• (A) an aromatic compound having at least two amino groups and having one of the following formulas (2) to (14):
• ##STR34## wherein the R.sup.1 groups may be the same or different and are each a member selected from the group consisting of --H, --NH.sub.2, --Cl, --OH, --NO.sub.2, --COCH.sub.3, --OCH.sub.3, --N(CH.sub.3).sub.2, --COOH, --SO.sub.3 H and alkyl groups of from 1 to 3 carbon atoms;
• ##STR35## wherein the R.sup.1 groups may be the same or different and each are as defined above, and the R.sup.2 groups may be the same or different and are each an amino group-containing alkyl group of from 1 to 10 carbon atoms;
• ##STR36## wherein the R.sup.1 groups may be the same or different and each are as defined above, and n is an integer of 1 or 2;
• ##STR37## wherein the R.sup.1 groups may be the same or different and each are as defined above, n is also as defined above, and X is a member selected from the group consisting of alkylene groups of from 1 to 5 carbon atoms, --CH.dbd.CH--, --N.dbd.N--, --NH--, --N(CH.sub.3)--, --CONH--, --P(.dbd.O)H--, --SO.sub.2 --, --O--, --S--, --Si(R).sub.2 -- (where R is an alkyl group of from 1 to 10 carbon atoms), and the group of the formula:
• ##STR38## wherein the R.sup.1 groups may be the same or different and each are as defined above, and n is also as defined above;
• ##STR39## wherein the R.sup.1 groups may be the same or different and each are as defined above, and n is also as defined above;
• ##STR40## wherein in the formulas (8) to (10), the R.sup.1 groups may be the same or different and each are as defined above, and n is also as defined above;
• ##STR41## wherein the R.sup.1 groups may be the same or different and each are as defined above, and n is also as defined above;
• ##STR42## wherein the R.sup.1 groups may be the same or different and each are as defined above, and n is also as defined above;
• ##STR43## wherein the R.sup.1 groups may be the same or different and each are as defined above, and n is also as defined above;
• ##STR44## wherein the R.sup.1 groups may be the same or different and each are as defined above, and n is also as defined above, and
• (B) an aromatic bis-ester anhydride having the following formula (1):
• ##STR45## wherein X is a divalent organic group selected from the groups consisting of:
• ##STR46## and Y groups may be the same or different and are each a trivalent organic group of the formula:
• ##STR47## in a solvent of water or a mixed solvent of water and an organic solvent miscible with water, wherein said organic solvent is contained in an amount of 50% by weight or less;
• said condensation product having been produced by condensing said components (A) and (B) in an organic solvent-based medium at a temperature of from room temperature to about 100.degree. C., followed by drying at a temperature of from room temperature to 100.degree. C.