Pigment grinding vehicles for use in water-dilutable paints
AssigneeVianova Kunstharz, A.G.
InventorsWillibald Paar, Helmut Honig
Life of this patent
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Abstract
The invention is directed to a process for the production of cationic binders for pigment pastes for water-dilutable paints, particularly for cathodic electrodeposition based on low molecular oxazolidine group carrying modified epoxy compounds, and to the pastes obtained. The process is characterized in that preferably aliphatic di- or polyepoxy compounds are reacted with primary mono- and/or diamines and optionally monocarboxy compounds and that oxazolidine groups are introduced into the molecule by reaction with carbonyl compounds. The products show extremely high pigment loading capacity and an excellent performance in cathodically depositable electrodeposition paints. The products permit formation of low solvent paint systems.
Claims33
Cationic binders water-soluble upon at least partial neutralization of basic groups contained therein comprising the reaction product of components (A) and (B), said component (A) being free of epoxide groups and prepared from a polyepoxide having a maximum molecular weight of 2000 and an amine containing a primary alkylamino group, said amine being present in an amount to provide from about 0.4 to 1.0 moles of primary amine groups for each mole of epoxide groups in said polyepoxide, and said component (B) being a carbonyl compound which is a member of the group consisting of aliphatic and aromatic aldehydes or ketones;
- said reaction product containing an oxazolidine ring formed through reaction of component (B) with component (A) and having a molecular weight of from about 500 to 4000, an oxazolidine equivalent of from about 250 to 1200, an amine value of at least 80 mg KOH/g and a proportion of aliphatic molecule segments of at least 30%.
A process for producing cationic binders which are water-soluble upon at least partial neutralization of basic groups contained therein comprising the steps of (1) reacting a polyepoxide having a maximum molecular weight of 2000 with an amine containing a primary alkylamino group, said amine being present in an amount to provide about 0.4 to 1.0 moles of primary amine groups for each mole of epoxide groups in said polyepoxide to provide component (A) which is substantially free of epoxide groups;
- and (2) reacting said component (A) which is free of epoxide groups with component (B) which is a carbonyl compound selected from the group consisting of aliphatic and aromatic aldehydes or ketones through oxazolidine ring formation;
- said reactions being carried out in order that the reaction product of components (A) and (B) have a molecular weight of from about 500 to 4000, an oxazolidine equivalent of from about 250 to 1200, an amine value of at least 80 mg KOH/g and a proportion of aliphatic molecule segments of at least 30%.
The process of calim 20 wherein each mole of epoxide groups are reacted with 0.3 to 0.7 moles of a primary-tertiary diamine, 0 to 0.6 moles of fatty acid having more than 8 carbon atoms or 0 to 0.7 moles of a primary monoamine having more than 3 carbon atoms and reacting after oxazolidine ring formation 50% of the free hydroxy groups with an oxazolidine group containing monoisocyanate.
Dependencies are inferred from the claim text.