Method for preparing microcapsules having improved pre-walls, and microcapsules and photosensitive materials produced thereby

Claim 1

A method for preparing microcapsules which comprises: dispersing a hydrophobic oily liquid containing a pre-wall former in a continuous aqueous phase, wherein said pre-wall former is selected from the group consisting of a polyvalent isocyanate, a polyvalent isothiocyanate, a polyvalent isocyanate adduct, a polyvalent isothiocyanate adduct, a cyanoacrylate, an isocyanato acrylate, and a mixture of a polyvalent isocyanate and a sulfonated polyvalent isocyanate, said aqueous phase containing at least one water soluble chain extender which also has a high affinity toward said oily liquid, said chain extender selected from the group consisting of melamine, methylol derivatives of melamine, ethylenediamine, diethylenetriamine, triethylenetetraamine, sorbitol, glycerine, N,N,N',N'-tetrakis (2-hydroxyethyl) ethylenediamine, lysine, glutamine, glactosamine, 2-amino-2-ethyl-1,3-propanediol, 2-(2-amino-ethylamino) ethanol, 1-(aminoethyl)-4-hydroxybenzyl alcohol, and 1,3-diamino-2-hydroxy propane wherein said chain extender reacts with said pre-wall former upon dispersion of said hydrophobic oily liquid in said continuous aqueous phase to form a thick, non-permeable pre-wall surrounding the oil droplets; and forming capsule walls around the pre-wall coated droplets of said hydrophobic oily liquid in said continuous aqueous phase.

Claim 2

A method for preparing microcapsules which comprises: dispersing a hydrophobic oily liquid containing a pre-wall former in a continuous aqueous phase, wherein said pre-wall former is selected from the group consisting of a polyvalent isocyanate, a polyvalent isothiocyanate, a polyvalent isocyanate adduct, a polyvalent isothiocyanate adduct, a cyanoacrylate, an isocyanato acrylate, and a mixture of a polyvalent isocyanate and a sulfonated polyvalent isocyanate, said aqueous phase containing at least one water soluble chain extender which also has a high affinity toward said oily liquid, said chain extender selected from the group consisting of melamine, methylol derivatives of melamine, ethylenediamine, diethylenetriamine, triethylenetetraamine, sorbitol, glycerine, N,N,N',N'-tetrakis (2-hydroxyethyl) ethylenediamine, lysine, glutamine, glactosamine, 2-amino-2-ethyl-1,3-propanediol, 2-(2-amino-ethylamino) ethanol, 1-(aminoethyl)-4-hydroxybenzyl alcohol, and 1,3-diamino-2-hydroxy propane wherein said chain extender reacts with said pre-wall former upon dispersion of said hydrophobic oily liquid in said continuous aqueous phase to form a thick, non-permeable pre-wall surrounding the oil droplets; and forming capsule walls around the pre-wall coated droplets of said hydrophobic oily liquid in said continuous aqueous phase.

Claim 14

A method for forming melamine-formaldehyde microcapsules which comprises: dispersing a hydrophobic oily liquid containing a pre-wall former in a continuous aqueous phase to form a dispersion, wherein said pre-wall former is selected from the group consisting of a polyvalent isocyanate, a polyvalent isothiocyanate, a polyvalent isocyanate adduct, a polyvalent isothiocyanate adduct, a cyanoacrylate, an isocyanato acrylate, and a mixture of a polyvalent isocyanate and a sulfonated polyvalent isocyanate, said aqueous phase containing at least one water soluble chain extender which also has a high affinity toward said oily liquid, said chain extender selected from the group consisting of melamine, methylol derivatives of melamine, ethylenediamine, diethylenetriamine, triethylenetetraamine, sorbitol, glycerine, N,N,N',N'-tetrakis (2-hydroxyethyl) ethylenediamine, lysine, glutamine, glactosamine, 2-amino-2-ethyl-1,3-propanediol, 2-)2-amino-ethylamino) ethanol, 1-(aminoethyl)-4-hyeroxybenzyl alcohol, 1,3-diamino-2-hydroxy propane wherein said chain extender reacts with said pre-wall former upon dispersion of said hydrophobic oily liquid in said continuous aqueous phase to form a thick, non-permeable pre-wall surrounding the oil droplets; and adding aqueous solutions of melamine and formaldehyde or an aqueous solution of a prepolymer thereof to said dispersion to form a melamine-formaldehyde condensate which enwraps the pre-wall coated oily particles forming said dispersion to form microcapsules.

Claim 15

A method for forming melamine-formaldehyde microcapsules which comprises: dispersing a hydrophobic oily liquid containing a pre-wall former in a continuous aqueous phase to form a dispersion, wherein said pre-wall former is selected from the group consisting of a polyvalent isocyanate, a polyvalent isothiocyanate, a polyvalent isocyanate adduct, a polyvalent isothiocyanate adduct, a cyanoacrylate, an isocyanato acrylate, and a mixture of a polyvalent isocyanate and a sulfonated polyvalent isocyanate, said aqueous phase containing at least one water soluble chain extender which also has a high affinity toward said oily liquid, said chain extender selected from the group consisting of melamine, methylol derivatives of melamine, ethylenediamine, diethylenetriamine, triethylenetetraamine, sorbitol, glycerine, N,N,N',N'-tetrakis (2-hydroxyethyl) ethylenediamine, lysine, glutamine, glactosamine, 2-amino-2-ethyl-1,3-propanediol, 2-)2-amino-ethylamino) ethanol, 1-(aminoethyl)-4-hyeroxybenzyl alcohol, 1,3-diamino-2-hydroxy propane wherein said chain extender reacts with said pre-wall former upon dispersion of said hydrophobic oily liquid in said continuous aqueous phase to form a thick, non-permeable pre-wall surrounding the oil droplets; and adding aqueous solutions of melamine and formaldehyde or an aqueous solution of a prepolymer thereof to said dispersion to form a melamine-formaldehyde condensate which enwraps the pre-wall coated oily particles forming said dispersion to form microcapsules.