EP0249685A2
Expired / Lapsed
EP
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Process of making dispersions of polymer encapsulated colorants or pigments
Assignee: Rotring International & Co Kg Te Hamburg Bo GmbH
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Filing: 1987-03-17
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Granted: —
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Expires: 2007-03-17
Abstract
Abstract A process for modifying colorants which comprise an active ingredient of solid primary particles in the submicron range by an encapsulation with polymer starting materials that are not substantially altered during the process. Writing fluids, textile colorlants and cosmetic inks are disclosed wherein the intrinsic physical qualities of a solid active material are modified to create a stable aqueous dispersion with performance and rheology characteristic of the polymer, and not of the active ingredient.
Inventors
- 👤 Fortunato J. Micale
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 19:27
CPC Classifications
C; C09; C09D; C09D5/00; A; A61; A61K; A61K8/00; A61K8/02; A61K8/11; A61Q; A61Q1/00; A61Q1/02; A61Q1/10; B; B01; B01J; B01J13/00; B01J13/02; C09B; C09B67/00; C09B67/0001; C09B67/0004; C09B67/0008; C09B67/0013; C09B67/0071; C09B67/0084; C09B67/0091; C09D11/00; C09D11/16; C09D17/00; C09D17/001; D; D06; D06P; D06P1/00; D06P1/0004; D06P1/0016; D06P1/44; A61K2800/00; A61K2800/40; A61K2800/41; A61K2800/412; A61K2800/42; A61K2800/43
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
194 words
A process for producing a colorant or pigment particularly useful in writing fluids, textile colorants and cosmetics comprising a stable aqueous suspension of submicron sized particles of polymer encapsulated active ingredient, wherein a polymer matrix surrounds a core of solid active ingredient, said process comprising the steps of A. mixing together an organic solvent, a polymer soluble in said solvent but substantially insoluble in water and an active ingredient which substantially is insoluble in water to form a homogeneous mixture, wherein said solvent is characterized by a vapor pressure higher than water and said mixing is continued until said active ingredient has dispersed in said solvent without appreciable agglomeration; and B. adding said solvent/polymer/active ingredient mixture to water, in a concentration range of 1.0% to 50.0% by weight, and dispersing until an emulsion results wherein solvent/polymer/active ingredient comprises a discontinuous phase, having a size less than 4 microns with water as the continuous phase, wherein said dispersing step is done under conditions where interfacial tension between the organic solvent and the water is less than approximately 10 dynes/cm; and C. removing substantially all of said solvent to obtain an aqueous suspension of said particles.
Claim 2
Dependent Claim
194 words
A process for producing a colorant or pigment particularly useful in writing fluids, textile colorants and cosmetics comprising a stable aqueous suspension of submicron sized particles of polymer encapsulated active ingredient, wherein a polymer matrix surrounds a core of solid active ingredient, said process comprising the steps of A. mixing together an organic solvent, a polymer soluble in said solvent but substantially insoluble in water and an active ingredient which substantially is insoluble in water to form a homogeneous mixture, wherein said solvent is characterized by a vapor pressure higher than water and said mixing is continued until said active ingredient has dispersed in said solvent without appreciable agglomeration; and B. adding said solvent/polymer/active ingredient mixture to water, in a concentration range of 1.0% to 50.0% by weight, and dispersing until an emulsion results wherein solvent/polymer/active ingredient comprises a discontinuous phase, having a size less than 4 microns with water as the continuous phase, wherein said dispersing step is done under conditions where interfacial tension between the organic solvent and the water is less than approximately 10 dynes/cm; and C. removing substantially all of said solvent to obtain an aqueous suspension of said particles.
Claim 3
Dependent Claim
32 words
The process according to claim 1, wherein, in said mixing step, the polymer is soluble to less than 5% in water, and the solvent is soluble to less than 20% in water.
Claim 4
Dependent Claim
81 words
The process according to claims 1 or 2, wherein in said mixing step, the active ingredient comprises solid primary elements having an element average diameter range of between 0.01 to 1.0 microns, and at least one primary element is encapsulated as a core within each polymer matrix wherein, further, the concentration ratio, by weight, of polymer to encapsulated material for each submicron sized particle is between 0.1 and 10.0, and each particle density is controlled by the pigment to polymer ratio.
Claim 5
Dependent Claim
52 words
The process according to claims 1 to 3, wherein said dispersing step further comprises the addition of a surfactant, in the range between 0.1% and 20%, by weight, of active ingredient material, and the concentration ratio, by weight, of polymer to encapsulated active material for each particle is between 0.1 and 10.0.
Claim 6
Dependent Claim
68 words
The process according to claims 1 to 4, wherein, in said mixing step, the concentration, by weight, of active material to solvent is between 0.1% and 20%, said polymer has a viscosity of less than 200-centipoise when dissolved in said solvent and said dispersing step is done ultrasonically, until substantially each droplet of dicontinuous phase comprises a submicron sized polymer matrix encapsulating active material as a solid core.
Claim 7
Dependent Claim
50 words
The process of claims 1 to 5 wherein said polymer is a system of epoxy resin and a curing agent, said dispersing step conditions are created by a surfactant that is cationic, and said curing agent migrates through the aqeuous suspension to cure the surface of each dispersed polymer particle.
Claim 8
Dependent Claim
32 words
The process of claims 1 to 6 wherein said solvent removal step further comprises applying heat to cure said polymer and remove some or all of the water of said aqueous suspension.
Claim 9
Dependent Claim
35 words
The process according to claims 1 to 7 wherein, in said mixing step, said polymer is selected from the group consisting of polyvinyl butyral, vinyl acetal polymers, butyrals, styrene/-maleic anhydride copolymers, and alkylated vinylpyrrolidone copolymers.
Claim 10
Dependent Claim
45 words
The process according to claims 1 to 8 wherein, in said mixing step, the polymer has a viscosity of less than 200 centipoise when dissolved in a solvent which is selected from the group consisting of ethyl acetate, methyl isobutyl ketone, methylene chloride, and tetrachloroethylene.
Claim 11
Dependent Claim
38 words
The process according to claims 4 to 9, wherein said surfactant is selected from the group consisting of quaternary ammonium salts, ethoxylated alkyl phenols, ethoxylated alcohols, ethoxylated fatty esters, sulfosuccinate derivatives, alkyl aryl sulfonates, sorbitan derivatives and lecithin.
Claim 12
Dependent Claim
98 words
A process according to claims 1 to 10 for producing a writing fluid comprising a low viscosity aqueous suspension of submicron sized particles of polymer encapsulated pigment, characterized by employing a film-forming polymer and a pigment comprising submicron sized primary particles, wherein said solvent is characterized by a vapor pressure higher than water and said mixing is continued until said pigment has been dispersed homogeneously as primary particles in said solvent and adding said solvent/polymer/ pigment mixture to water and dispersing until an emulsion results wherein solvent/polymer/pigment droplets with an average diameter less than 2 microns are formed.
Claim 13
Dependent Claim
95 words
The process according to claim 11, wherein, in said mixing step, the polymer is soluble to less than 5% in water, the solvent is soluble to less than 20% in water, and the amounts of polymer/pigment in said mixing step have a combined average density of approximately 1.0 g/cm 3 ; wherein further the concentrations of polymer and pigment are chosen so that substantially all of said pigment remains in the discontinuous liquid phase during said dispersing step, and each particle further has a density in the range of 0.9 to 1.1 g/cm 3 .
Claim 14
Dependent Claim
149 words
A process according to claims 1 to 10 for forming a textile colorant which comprises creating a polymer matrix that surrounds a core of solid colorant wherein A. said polymer is thermoplastic and to less than 5% soluble in water, and said dispersing step further comprises the addition of a surfactant, in the range between 0.1% and 20%, by weight, of colorant, and the concentration ratio, by weight, of polymer to encapsulated colorant for each submicron sized particle is between 0.1 and 10.0, or B. said polymer is a thermosetting system of epoxy resin which requires a curing agent, said dispersing step comprises adding a cationic surfactant, and said curing agent is added in a continuous aqueous phase, in order to contact the dispersed polymer particle surfaces, whereby upon applying heat to particles that have been applied to a textile surface, the particles will thermoset upon said textile surface.
Claim 15
Dependent Claim
40 words
The process according to claim 13 wherein a cationic surfactant is used in said dispersing step and a water soluble curing agent is applied to said particles from a separate bath, after said particles have been applied to a substrate.
Claim 16
Dependent Claim
77 words
A process according to claims 1 to 10 for encapsulating submicron sized pigment particles for use in cosmetics wherein said cosmetic carrier comprises the aqeuous phase resulting from said solvent removal step, said polymer is non-film forming, said solvent is selected from the group consisting of methylene chloride and ethyl acetate, and said aqueous mixture comprises a dispersion of submicron polymer particles containing one or more primary pigment particles non-pigmented polymer particles, and optionally unencapsulated pigment particles.
Claim 17
Dependent Claim
40 words
The process according to claim 15 wherein said solvent is selected from the group consisting of methylene chloride and ethyl acetate, and said pigment is selected from the group consisting of oxides of iron, and pigments approved for cosmetic use.
References Cited (Backward Citations)
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