Encapsulation process and capsules produced thereby
AssigneeStauffer Chemical Company
InventorHerbert B. Scher
Life of this patent
Estimating the term…
Abstract
Encapsulation process to prepare encapsulated water-immiscible material employing an organic polyisocyanate intermediate to form a polyurea capsule enclosure around a water-immiscible material dispersed in an aqueous continuous phase comprising the steps of heating the dispersion or adding a catalyst, and optionally adjusting the pH to a value between 0 and 14.
Claims106
A process of encapsulating water-immiscible material within discrete capsules of polyurea without addition of a second reactant, whereby hydrolysis of an isocyanate monomer to form an amine takes place which in turn reacts with another isocyanate monomer to form polyurea, which comprises the steps:
- (a) providing, at room temperature, a dispersion of (i) a water-immiscible phase comprising the water-immiscible material to be encapsulated and an organic polyisocyanate in (ii) an aqueous phase comprising a solution of water, a surfactant and a protective colloid;
- and
- (b) heating and maintaining said dispersion in a temperature range of about 40.degree. C. to about 90.degree. C.;
- whereupon said water-immiscible material is encapsulated within discrete polyurea capsular enclosures directly usable without further separation or purification.
A process of encapsulating water-immiscible material within discrete capsules of polyurea without addition of a second reactant, whereby hydrolysis of an isocyanate monomer to form an amine takes place which in turn reacts with another isocyanate monomer to form polyurea, which comprises the steps:
- (a) providing in an aqueous phase at room temperature a solution comprising water, a surfactant and a protective colloid;
- (b) adding to said aqueous phase a water-immiscible phase comprising the water-immiscible material to be encapsulated and an organic polyisocyanate;
- (c) dispersing at room temperature said water-immiscible phase in said aqueous phase;
- (d) heating and maintaining the dispersed water-immiscible phase and aqueous phase in a temperature range of about 40.degree. C. to about 90.degree. C.;
- whereupon said water-immiscible material is encapsulated within discrete polyurea capsular enclosures directly usable without further separation or purification.
A process of encapsulating water-immiscible material within discrete capsules of polyurea without addition of a second reactant, whereby hydrolysis of an isocyanate monomer to form an amine takes place which in turn reacts with another isocyanate monomer to form polyurea, which comprises the steps:
- (a) providing in an aqueous phase at room temperature a solution comprising water and a surfactant;
- (b) adding to said aqueous phase a water-immiscible phase comprising a water-immiscible material to be encapsulated and an organic polyisocyanate;
- (c) dispersing at room temperature said water-immiscible phase in said aqueous phase to form a dispersion of droplets of the water-immiscible phase in said aqueous phase;
- (d) adding to said dispersion a protective colloid;
- (e) heating and maintaining said dispersion in a temperature range of about 40.degree. C. to about 90.degree. C. with mild agitation;
- whereupon said water-immiscible material is encapsulated within discrete polyurea capsular enclosures directly usable without further separation or purification.
A process of encapsulating water-immiscible material within discrete capsules of polyurea without addition of a second reactant, whereby hydrolysis of an isocyanate monomer to form an amine takes place which in turn reacts with another isocyanate monomer to form polyurea, which comprises the steps:
- (a) providing, at room temperature, a dispersion comprising (i) a water-immiscible phase comprising the water-immiscible material to be encapsulated and an organic polyisocyanate in (ii) an aqueous phase comprising a solution of water, a surfactant and a protective colloid, which dispersion contains a catalyst capable of increasing the rate of reaction of said organic polyisocyanate to form said polyurea;
- and
- (b) maintaining said dispersion at room temperature whereupon said water-immiscible material is encapsulated within discrete polyurea capsular enclosures directly usable without further separation or purification.
A process for encapsulating water-immiscible material within discrete capsules of polyurea without addition of a second reactant, whereby hydrolysis of an isocyanate monomer to form an amine takes place which in turn reacts with another isocyanate monomer to form polyurea, which comprises the steps:
- (a) providing, at room temperature, in an aqueous phase a solution comprising water and a surfactant;
- (b) adding to said aqueous phase, at room temperature, a water-immiscible phase comprising organic polyisocyanate, a water-immiscible material to be encapsulated, and a catalyst capable of increasing the rate of reaction of said organic polyisocyanate to form polyurea;
- (c) dispersing said water-immiscible phase in said aqueous phase to establish droplets of the water-immiscible phase in the aqueous phase;
- (d) maintaining the dispersion at room temperature;
- and
- (e) adding to the dispersion a protective colloid;
- whereupon said water-immiscible material is encapsulated within discrete polyurea capsular enclosures directly usable without further separation or purification.
The process of claim 104 wherein said catalyst is selected from the group consisting of a basic organic tertiary amine catalyst and an alkyl tin acetate catalyst.
Dependencies are inferred from the claim text.