Coatings and films derived from clay/wax nanocomposites
AssigneeThe University of Chicago
InventorsDavid J. Chaiko, Argentina A. Leyva
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Abstract
The invention provides methods for making clay/wax nanocomposites and coatings and films of same with improved chemical resistance and gas barrier properties. The invention further provides methods for making and using emulsions of such clay/wax nanocomposites. Typically, an organophillic clay is combined with a wax or wax/polymer blend such that the cohesion energy of the clay matches that of the wax or wax/polymer blend. Suitable organophilic clays include mica and phyllosilicates that have been surface-treated with edge or edge and surface modifying agents. The resulting nanocomposites have applications as industrial coatings and in protective packaging.
Claims33
A method of preparing a nanocomposite comprising combining a surface-treated organophilic clay and a melt comprising a wax or wax and polymer, wherein the cohesion energies of the organophilic clay and the wax or wax and polymer are sufficiently matched in both the melt and solid states to produce and maintain a homogenous dispersion of the organophilic clay in both the liquid and solid nanocomposite, and further wherein the surface-treated organophillic clay comprises an anionic edge modifying surfactant adsorbed onto an edge thereof.
A method for preparing an emulsion comprising mixing a nanocomposite melt and an aqueous phase with sufficient shear to produce an emulsion, wherein the aqueous phase contains at least one surfactant capable of stabilizing the nanocomposite as an emulsion, wherein
- the nanocomposite melt is prepared by combining an organophilic clay and a melt comprising a wax or wax and polymer, wherein the cohesion energies of the organophilic clay and the wax or wax and polymer are sufficiently matched in both the melt and solid states to produce and maintain a homogenous dispersion of the organophilic clay in both the liquid and solid nanocomposite;
- and
- the surfactant is prepared in situ by combining a strong base with a weak organic acid;
- wherein the base is selected from the group consisting of potassium hydroxide, ammonia and organoamines;
- and the acid is a carboxylic acid.
Dependencies are inferred from the claim text.