Process of producing microcapsules and product thereof

a microcapsule and production process technology, applied in the field of making microcapsules, can solve the problems of poor batch-to-batch reproducibility, poor microcapsule generation efficiency, and poor quality of microcapsules, and achieve excellent high temperature resistance to premature release of encapsulated materials, good manufacturability, and excellent resistance to low pressure.

Inactive Publication Date: 2005-07-28
EASTMAN KODAK CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0015] (4) curing the encapsulating material associated with the microparticles to form the microcapsules. It further provides microcapsules made by the above process and an imaging material comprising said microcapsules. The microcapsules produced by the process of the invention have a narrow size distribution, wherein the size is controlled not by the amount of shear, but rather by the type and amount of stabilizers utilized. The process is capable of producing microcapsules which are very robust and have excellent resistance to low pressure during normal storage and handling process, and which have excellent high temperature resistance to premature release of encapsulated materials. The process has good manufactuability with excellent batch to batch reproducibility.

Problems solved by technology

It is well known in the art that microcapsules generated by the above process have a broad size distribution and poor batch-to-batch reproducibility.
If the oxygen re-infiltrates the light sensitive composition, the photographic speed of the media is very poor.
Microcapsules need to be resistant to low pressure during normal storage and handling process, otherwise premature release of the core material will occur.

Method used

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  • Process of producing microcapsules and product thereof
  • Process of producing microcapsules and product thereof
  • Process of producing microcapsules and product thereof

Examples

Experimental program
Comparison scheme
Effect test

example 3

n)

[0112] The organic phase and aqueous phase (Versa TL 502 / TL130: 100 / 0) were mixed using a propeller mixer at 1000 rpm for 10 minutes at room temperature to form a premix. The premix was then passed through a homogenizer (Microfluidizer) once at a pressure greater than 6000 psi. The resultant mixture was heated in a 60° C. bath for 10 minutes before a melamine formaldehyde prepolymer solution was added. The prepolymer was formed by reacting 3.9 grams of melamine and 6.5 grams of 37% formaldehyde solution in 44 grams of water (pH>8). The pH was adjusted to pH 6 with H3PO4 and the reaction mixture was heated to 70 C for 2 hours while mixing at 1500 rpm. A solution of 2.5 grams of urea in 7 grams of water was then added to the reaction mixture and reaction was allowed to continue at 70° C. for 40 minutes. The stirring was adjusted to 500 rpm. The pH was adjusted to 9 using a 10% NaOH solution.

[0113] A drop of microcapsule solution was place on a cover glass and its photomicrograph wa...

example 4

n)

[0114] The organic phase and aqueous phase (Versa TL 502 / TL130: 30 / 70) were mixed using a propeller mixer at 1000 rpm for 10 minutes at room temperature to form a premix. The premix was then passed through a homogenizer once at a pressure greater than 6000 psi. The resultant mixture was heated in a 60° C. bath for 10 minutes before a melamine formaldehyde prepolymer solution was added. The prepolymer was formed by reacting 3.9 grams of melamine and 6.5 grams of 37% formaldehyde solution in 44 grams of water (pH>8). The pH was adjusted to pH 6 with H3PO4 and the reaction mixture was heated to 70 C for 2 hours while mixing at 1500 rpm. A solution of 2.5 grams of urea in 7 grams of water was then added to the reaction mixture and reaction was allowed to continue at 70° C. for 40 minutes. The stirring was adjusted to 500 rpm. The pH was adjusted to 9 using a 10% NaOH solution.

[0115] A drop of microcapsule solution was place on a cover glass and its photomicrograph was taken. The micr...

example 5 (

Invention)

[0116] The organic phase and aqueous phase (Versa TL 502 / TL130: 20 / 80) were mixed using a propeller mixer at 1000 rpm for 10 minutes at room temperature to form a premix. The premix was then passed through a homogenizer once at a pressure greater than 6000 psi. The resultant mixture was heated in a 60° C. bath for 10 minutes before a melamine formaldehyde prepolymer solution was added. The prepolymer was formed by reacting 3.9 grams of melamine and 6.5 grams of 37% formaldehyde solution in 44 grams of water (pH>8). The pH was adjusted to pH 6 with H3PO4 and the reaction mixture was heated to 70 C for 2 hours while mixing at 1500 rpm. A solution of 2.5 grams of urea in 7 grams of water was then added to the reaction mixture and reaction was allowed to continue at 70° C. for 40 minutes. The stirring was adjusted to 500 rpm. The pH was adjusted to 9 using a 10% NaOH solution.

[0117] A drop of microcapsule solution was place on a cover glass and its photomicrograph was taken. ...

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Abstract

This invention relates to a process for preparing microcapsules containing a hydrophobic liquid core material, the process comprising: (1) mixing an organic liquid phase which comprises the hydrophobic liquid core material with an aqueous phase comprising a stabilizer to form a premix; (2) homogenizing the premix by forcing the premix under pressure through a high pressure passage into a low pressure area to produce a microparticle dispersion, said microparticles having a mean size of greater than 1.0 micron, (3) adding an encapsulating material prior to step (4); and (4) curing the encapsulating material associated with the microparticles to form the microcapsules.

Description

FIELD OF THE INVENTION [0001] This invention relates to a method of making microcapsules containing a hydrophobic core material. It more specifically relates to a light sensitive and heat or pressure developable imaging element comprising an image forming unit comprising photosensitive microcapsules. BACKGROUND OF INVENTION [0002] Microencapsulation is the envelopment of an active agent or a core material within a solid coating. The active or core material can be in the form of a solid particle, a liquid droplet, or a gas bubble. The solid coating used to form the capsule may be, for example, an organic polymer, a wax, or an inorganic oxide. A capsule is characterized in general by parameters such as particle size and distribution, particle geometry, active contents and distribution, release mechanism, and storage stability. [0003] Many encapsulation processes have been reported in the literature; only a few, however, have been commercialized. These include interfacial and in-situ p...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): B01J13/02B01J13/04G03F7/00
CPCG03F7/002B01J13/04
Inventor WANG, YONGCAIHODERLEIN, PAUL M.SMITH, DENNIS E.ROCHESTER, PETER D.
Owner EASTMAN KODAK CO
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