Polymer, process and use

Abstract

There is described a process for producing a gel free hyperbranched polyamide polymer P having a polydispersity of at least 1.1 and a weight average molecular weight of at least 300 daltons, having primary amino groups (useful as a crosslinker). The process comprises the step of reacting Reagent A, a compound comprising at least one amino group (—NH2) and one functional group selected from the group consisting of a further amino group (—NH2), thiol (—SH) and a secondary amine radical (—NHR); (where R denotes a hydrocarbo group) (=functional amine) and Reagent B, an alpha-beta unsaturated Michael-reactive ester comprising a plurality of ester groups (=diester); in a molar ratio of amine A to diester B greater than 1 but less than 3 (preferably 2.1 to 2.9); to form the polyamide in a two stage reaction Michael addition and then amidation. The amine in kept in excess with at least 5% of water by total weight of the amine and diester, a reaction temperature less than the boiling point of the amine; and is held under reduced pressure (30 mbar to 1 atms). Gelation does not occur even after substantially all ethylenic (—C═C—) double bonds; and >95% ester [—C(O)═O] groups have reacted. This violates the Flory rules which predict a gel would form based on the number of functional groups present and their degree of conversion. These polymers may be used as a replacement for polyethylene imine (PEI) for example on plastics; in coatings, colours and/or adhesives; with metals; on textiles and fibres; in water treatment, paper, mineral processing and/or chemically modified Various chemical modifications and further reactions of these polymers are also described. A diverse range of other uses are also described including as additives for composite compositions, such as specialty additives for super-plasticizers in concrete admixtures.

Dependencies are inferred from the claim text.