| 主权项 |
1. A process for the preparation of a core-shell microcapsule, said process comprising the steps of:
1) preparing an oligomeric composition comprising the reaction product of, or obtainable by reacting together:
a) a polyamine component in the form of melamine or of a mixture of melamine and at least one C1-4 compound comprising two NH2 functional groups;b) an aldehyde component in the form of a mixture of glyoxal, a C4-6 2,2-dialkoxy-ethanal and optionally a glyoxalate, said mixture having a molar ratio glyoxal/C4-6 2,2-dialkoxy-ethanal comprised between 1/1 and 10/1; andc) a protic acid catalyst; 2) preparing an oil-in-water dispersion, wherein the droplet size is comprised between 1 and 600 μm, and comprising:
i) an oil;ii) a water medium;iii) at least an oligomeric composition as obtained in step 1);iv) at least a cross-linker selected amongst:
A) C4-C12 aromatic or aliphatic di- or tri-isocyanates and their biurets, triurets, trimers and trimethylol propane-adduct; and/orB) a di- or tri-oxiran compounds of formula
A-(oxiran-2-ylmethyl)n wherein n stands for 2 or 3 and A represents a C2-C6 group optionally comprising from 2 to 6 nitrogen and/or oxygen atoms;v) optionally a C1-4 compound comprising two NH2 functional groups; 3) heating said dispersion; 4) cooling said dispersion; and 5) optionally adding to the dispersion of step 4) at least one cationic polymer and/or urea or ethylene urea; and 6) optionally drying the final dispersion to obtain the dried core-shell microcapsule. |
