Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
  • B01J13/02—Making microcapsules or microballoons
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
  • B01J13/02—Making microcapsules or microballoons
  • B01J13/06—Making microcapsules or microballoons by phase separation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
  • B01J13/02—Making microcapsules or microballoons
  • B01J13/06—Making microcapsules or microballoons by phase separation
  • B01J13/14—Polymerisation; cross-linking
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
  • Y10T428/2984—Microcapsule with fluid core [includes liposome]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
  • Y10T428/2984—Microcapsule with fluid core [includes liposome]
  • Y10T428/2985—Solid-walled microcapsule from synthetic polymer
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
  • Y10T428/2989—Microcapsule with solid core [includes liposome]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
  • Y10T428/2991—Coated

Definitions

• This invention relates to microencapsulated particles.
• This invention relates to microencapsulated particles.
• this invention relates to microencapsulated particles that are useful in electroluminescent applications. This invention also relates to a process for the microencapsulation of these particles.
• this invention is applicable to the microencapsulation of polymer (or
• polymeric light-emitting diodes also referred to as PLEDs
• OLEDs organic light-emitting diodes
• PLEDs are thin film displays that are created by sandwiching an
• PLEDs enable full spectrum color
• OLEDs are display devices that sandwich carbon-based films
• the organic films consist of a hole-injection layer, a hole-transport layer, an emissive layer and an electron-transport layer.
• the injected positive and negative charges recombine in the emissive layer and create electoluminescent light.
• Microencapsulated particles are known in the prior art. Bayless et al. U.S. Patent
• liquid manufacturing vehicle wherein the capsules contain water or aqueous solutions.
• This patent discloses a splecific process for manufacturing minute capsules wherein the
• capsule wall material is poly (ethylene-vinyl acetate) that is hydrolyzed to a narrowly
• Bayless U.S. Patent 4,107,071 (1978) discloses microcapsules having a capsule
• Phosphor particles are used in a variety of applications, such as flat panel displays
• light emission by phosphor particles may be stimulated by applications of heat
• thermoluminescence light
• photoluminescence high energy radiation
• high energy radiation e.g., x-rays or
• the present invention provides microencapsulated particles
• present invention also provides a process for the microencapsulation of these particles.
• microencapsulated particles of this specification As will be seen in greater detail below, the microencapsulated particles of this specification
• an object of this invention is to provide microencapsulated particles.
• Another object of this invention is to provide microencapsulated particles having
• Another object of this invention is to provide microencapsulated particles having
• Another object of this invention is to provide microencapsulated phosphor
• Another object of this invention is to provide microencapsulated polymer light-
• Another object of this invention is to provide microencapsulated organic light- emitting diodes.
• Still another object ot mis invention is to provide microencapsulated phosphor particles having improved impermeability to moisture.
• Still another object of this invention is to provide microencapsulated phosphor
• Still another object of this invention is to provide a process for the microencapsulation of particles.
• Still another object of this invention is to provide a process for the
• Still another object of this invention is to provide a process for the
• Yet still another object of this invention is to provide a process for the
• Yet still another object of this invention is to provide a process for the microencapsulation of polymer light-emitting diodes.
• Yet still another object of this invention is to provide a process for the microencapsulation of organic light-emitting diodes.
• Yet still another object of this invention is to provide a process for the
• Yet still another object of this invention is to provide a process for the
• FIG. l BRIEF DESCRIPTION OF THE DRAWINGS
• Fig. 1 is a chart showing the effect of exposure (measured in hours) on brightness
• electroluminescent lamps containing phosphors that have not been encapsulated containing phosphors that have not been encapsulated.
• the electroluminescent lamps produced no halos or glare and could be seen
• Fig. 2 is a graphical representation of the relation between capsule quality and
• quality capsules can be prepared with the quality improving as 43 percent hydrolysis is approached.
• the capsule quality is excellent for this invention, and the capsules are particularly suited for containing phosphors, polar
• capsule quality is at a maximum for the present invention.
• the present invention relates to microencapsuIated particles, especially
• microencapsulated phosphor particles which are manufactured y a process that
• nonpolar solvent for the polymer wherein the solvent is not a solvent for particles of the
• microencapsulated phosphors of the present invention comprise a core formed
• the sheath comprises a hydrolyzed, cross-linked polymer that is sufficiently impermeable to moisture (especially water) to protect the phosphor from deteriorating exposure to moisture, but the cross-linked polymer is sufficiently permissive to the transmission of illuminating energy to activate the phosphor to a
• microencapsulates of the present invention are especially
• phosphor particles are mixed with a film-
• the mixture is agitated to dissolve the polymer in the liquid vehicle
• particles are recovered from solution, washed and then dried if necessary.
• the polymer Upon recovery of the phosphor capsules from the process, preferably the polymer
• sheaths are contacted with a halogenated hydrocarbon to cause the polymer sheaths to
• Preferred halogenated hydrocarbons are l,l,2-trichloro-l,2,2-trifluoroethane and dibromotetrafluoroethane.
• the polymer should be substantially dielectric, preferably with a dielectric
• a preferred polymer is a hydrolyzable, cross-linkable ethylene-vinyl acetate copolymer.
• the polymer should be pyrolyzable.
• a preferred film-forming polymer for use in the present invention is a poly
• a preferred liquid vehicle for dissolving the polymer is toluene.
• the polymeric capsule wall material can be any film-forming polymeric material
• the capsule wall material preferably is partially
• material can be within the relatively broad range of about 38 to about 55 percent, preferably within the range of about 44 to about 46 percent.
• the amount of ethylene groups present is also important and can
• the mol ratio of ethylene groups to the sum of ethylene groups, vinyl alcohol groups and vinyl acetate groups can be about 0.6 to about 0.88;
• the partially-hydrolyzed poly (ethylene-vinyl acetate) suitable for practicing the
• present invention has a molecular weight of about 50,000 and a melt index (using a 2160
• the molecular weight of the copolymer is not overly critical, except
• cellulose acylated cellulose (e.g., cellulose acetate butyrate) and the like.
• Typical illustrative water-immiscible liquids which can serve as liquid vehicles for
• the present process are solvents for the polymeric wall material and include the liquid
• aromatic hydrocarbons such as toluene, xylene, benzene, chlorobenzene and the like.
• liquid halogenated hydrocarbons such as trichloroethylene, tetrachloroethylene, carbon tetrachloride, methyl chloride and the like.
• solvents such as cyclohexanol, methyl isobutyl ketone, l-methyl-2-pyrrolidone, butanol and the like.
• the phosphor particles utilized in the present invention are in micro- particulate form, generally in the range of from about 1 to about 100 microns in cross-
• inventions have a core comprised of a phosphor particle encapsulated by a protective wall
• microencapsulates are useful for illuminating road signs, intersections, house numbers, instrument panels, aircraft
• the microencapsulates may
• Typical phosphors include oxygen-dominated phosphors such as:
• diamond-lattice phosphors such as sulfides, selenides and tellurides of zinc, cadmium
• mercury e.g., ZnS:AgCl; ZnS:CuCl; ZnS:MnCl and ZnS activated by other
• activators such as Mn(II), P, As, Sb, V, Fe and Ti, with coactivators such as the halogens,
• Al, Ga and In, and ZnS activated by combinations of the rare earths with either Ag or Cu;
• suifides e.g. CaS, SrS, etc., containing europium, cerium, copper, manganese, samarium,
• organic phosphors such as stilbene, naphthalene,
• electroluminescence which is defined as the direct conversion of electrical energy into
• a second phase of copper sulfide is preferred as a core material.
• the emission of the electroluminescent process is similar to the photoluminescence observed under ultraviolet
• Flexible electroluminescent lamps with a thickness of less than 1/32 in. have
• the excitation is attributed to carrier injection in a p-n junction.
• the microencapsules will typically be supported in a matrix in which the media of
• the matrix surrounding the phosphor particles should have a dielectric constant in the
• microencapsules in the supporting matrix to the resultant electromagnetic wave energy
• microencapsulated phosphors of this invention can also be deposited on a
• This method of depositing phosphor particles may be
• copolymer as well as other alternative polymers, is suitable for this purpose.
• microencapsulates that contain phosphor particles can be produced by
• immiscible liquid vehicle capable of dissolving the polymeric material but not the
• the phosphor is in the form of phosphor particles
• the phosphor material can be microencapsulated in liquid form, and this is a
• the produced mixture is agitated to disperse the phosphor particles as individual minute core-forming entities throughout the liquid vehicle to form an agitated system in which the liquid vehicle constitutes the major
• the polymeric film-forming material is then dissolved in the
• phase separation is induced within the agitated system to separate
• sheaths is cross-linked to form protective walls around the phosphor cores.
• protective walls may be contacted with a halogenated hydrocarbon for a time period
• a preferred process for microencapsulating phosphor particles such as zinc
• sulfide doped with copper includes subjecting the phosphor particles to a coacervative
• microencapsulation process which is of the liquid-liquid phase separation type, utilizing an organic liquid vehicle and a partially hydrolyzed ethylene-vinyl acetate copolymer as
• the film-forming wall material The film-like polymer wall of the microencapsule
• microencapsule entities are then treated with a finely divided silica gel to improve their
• phase separation may be induced in
• phase separation-inducing material typically by introducing into the mixture a phase separation-inducing material.
• a phase separation-inducing material typically by introducing into the mixture a phase separation-inducing material.
• phosphor particles than for the film-forming polymer may be dissolved in the liquid
• non-polymeric material that is not a solvent for the film-forming
• polymer or the phosphor particles may be utilized as the phase separation-inducing
• phase separation may be induced, with or without
• phase separation-inducing material may be introduced into the
• phase separation-inducing material may be initially mixed with
• Suitable phase separation-inducing materials for the present invention are
• phase separation-inducing material is incompatible with the polymeric film-
• phase separation-inducing materials of this type are
• polymeric materials such as silicone oils, e.g., polydimethyl siloxane, and the like; poly-
• olefins e.g., polybutadiene having a molecular weight of about 8,000 to about 10,000; polybutene having a molecular weight of about 330 to about 780; unhydrolyzed ethylene-
• phase separation-inducing material that can be utilized to initially
• microcapsule wall or sheath is a non-polymeric liquid that is a non-solvent for
• phase separation-inducing materials of the non-solvent type are illustrated.
• the vegetable oils e.g., the semi-drying oils such as cottonseed oil or corn oil
• the semi-drying oils such as cottonseed oil or corn oil
• drying oils such as linseed oil, soybean oil and the like.
• non-solvent type are mineral oils, halogenated mineral oils, liquid saturated alicyclic hydrocarbons such as cyclohexane, cycloheptane, and the like, liquid, saturated straight-
• chain aliphatic hydrocarbons such as n-hexane, n-heptane and the like.
• the film-forming polymeric material the phase separation-inducing material
• phase separation-inducing material at an elevated temperature of about 30°C or
• the order of addition can be reversed.
• the film-forming polymeric material and the phase separation-inducing material can be combined with the liquid vehicle simultaneously.
• phase separation-inducing material depend on the particular materials that are used and
• the film-forming polymer constitutes about 0.5 to about 5
• separation inducing material constitutes about 0.5 to about 25 percent (preferably about 8
• entities constitute about 2 to about 30 percent (preferably about 15 to about 20 percent) of
• phase ratio of the phosphor core to the protective polymeric wall or sheath typically in the range of from about 3:1 to about 20:1,
• phase-separation can be induced within the system by first forming
• solution temperature is lowered by at least about 10°C. to effect the microencapsule wall formation around the phosphor- cores dispersed in the solution.
• solubility of the polymeric material in the liquid vehicle decreases with
• phase separation is induced by elevating the temperature of the
• phase separation inducing techniques can also be used.
• the present invention include the diisocyanates or polyisocyanates, e.g., toluene
• diisocyanate with or without a catalyst present.
• a catalyst particularly preferred is a toluene
• cross-linking agents are the diacid halides such as malonyl
• alkali alkoxides such as the sodium, potassium, lithium and cesium methoxides, ethoxides,
• the cross-linking or hardening agent can be dissolved
• diacid halides when using the diacid halides can be about 5 to about 15 minutes, and when using the diisocyanates can be about 5 to about 15 hours, depending on reaction conditions.
• the microencapsule sheath can also be hardened or cross-linked by exposing the sheath to high energy ionizing radiation such as accelerated electrons, X-rays, gamma rays, alpha particles, neutrons and the like.
• high energy ionizing radiation such as accelerated electrons, X-rays, gamma rays, alpha particles, neutrons and the like.
• Permeability of the protective wall of the microencapsules is dependent to a
• Cross-linking of the polymer may also be accomplished in differing manners.
• cross-linking agent is added to the system, with preferred cross-linking
• agents being diisocyanates, polyisocyanates, diacid halides, difunctional hydrides and
• cross-linking can be induced by applying radiation to the
• Microencapsules of various sizes can be manufactured when practicing the present
• microencapsules is about 1 micron to about 15,000 microns in average diameter
• microencapsules can be manufactured to contain varying amounts of phosphor core
• the core material constitutes about 50 to about 97 percent of the total weight of each microencapsule.
• HEVA vinyl acetate copolymer
• the solution is allowed to cool to a dispersion temperature of about 30°C to
• phase separating inducer such as cottonseed oil
• phase-separation temperature in the range from about
• phase separation inducer can also be added earlier, before the phosphor cores.
• the wall-forming HEVA copolymer material separates out as another discontinuous phase, i.e., a third phase, that preferentially wets the phosphor cores and forms a sheath or capsule wall.
• This third phase is a relatively
• concentrated solution or gel of the polymeric material is more viscous than the continuous phase, and in addition, is of sufficiently high viscosity to maintain a
• the produced mixture is further cooled to a temperature in the range of
• microencapsules are recovered, washed and dried. Then, if desired, the microcapsules are contacted with a halogenated hydrocarbon,
• microencapsules are dried, and preferably treated with a
• silica gel in the form of micron-size particles to prevent aggregation of the microencapsules.
• HEVA hydrolyzed ethylene-vinyl acetate copolymer
• variable speed stirring motor The HEVA copolymer is dissolved in the toluene by
• particles having average diameters in the range of about 10 microns to about 40 microns,
• the stirrer increased to 480 rpm to disperse the phosphor particles substantially uniformly throughout the toluene solution.
• cottonseed oil is added to the stirrer
• the produced mixture is further cooled to about
• the suspension is repeated three more times, and the microncapsules are then filtered off
• Syloid/microencapsule mixture is passed through a 500 micron sieve and then through a
• Example 1 The process of Example 1 is successfully repeated using 900 grams of blue
• phosphor particles having average diameters in the range of about 10 microns to about 40
• Example 1 The process of Example 1 is successfully repeated using 600 grams of yellow
• phosphor particles having average diameters in the range of about 10 microns to about 40
• Example 1 The process of Example 1 is successfully repeated using the hydrolyzed ethylene-

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Dispersion Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Manufacturing Of Micro-Capsules (AREA)
• Luminescent Compositions (AREA)
• Electroluminescent Light Sources (AREA)
• Medicinal Preparation (AREA)

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• 2002
  • 2002-11-14 US US10/298,419 patent/US6833191B2/en not_active Expired - Fee Related
  • 2002-11-19 JP JP2003545471A patent/JP2005509518A/ja active Pending
  • 2002-11-19 KR KR1020047007686A patent/KR100940137B1/ko not_active Expired - Fee Related
  • 2002-11-19 AU AU2002352819A patent/AU2002352819A1/en not_active Abandoned
  • 2002-11-19 CN CNB02827279XA patent/CN100333895C/zh not_active Expired - Fee Related
  • 2002-11-19 WO PCT/US2002/037246 patent/WO2003043813A1/en not_active Ceased
  • 2002-11-20 TW TW091133825A patent/TW590797B/zh not_active IP Right Cessation
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• 2007
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• 2008
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