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US 4,542,042 AGranted
Process for preparing free-flowing ethylcellulose microcapsules
AssigneeTanabe Seiyaku Co., Ltd.
InventorsMasayoshi Samejima, Goichi Hirata, Takashi Ishibashi
Life of this patent
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Abstract
A process for preparing free-flowing microcapsules by taking advantage of the phase-separation of ethylcellulose in cyclohexane is disclosed. In this process, a hydrocarbon compound which is soluble in cyclohexane and have a molecular weight of 150 to 3,000 and a solubility parameter (.delta., at 25.degree. C.) of 7 to 10 (cal/cm.sup.3).sup.1/2 is used as the phase-separation-inducing agent.
Claims19
A method of preparing free-flowing microcapsules which comprises
- (i) dispersing particles of a core material in a cyclohexane solution containing ethylcellulose and a hydrocarbon compound, said hydrocarbon compound being soluble in cyclohexane and present in an amount of 0.1 to 20 grams per 100 ml of cyclohexane, said hydrocarbon compound further having a molecular weight of 150 to 3,000 and a solubility parameter (.delta., at 25.degree. C.) of 7 to 10 (cal/cm.sup.3).sup.1/2, to form a dispersion,
- (ii) cooling said dispersion until ethylcellulose separates out from said dispersion to form coating walls on said particles of said core material to form microcapsules.
A method of preparing free-flowing microcapsules which comprises
- (i) dispersing particles of a core material in a cyclohexane solution containing ethylcellulose and a hydrocarbon compound, said hydrocarbon compound being soluble in cyclohexane and present in an amount of 0.1 to 20 grams per 100 ml of cyclohexane, said hydrocarbon compound further having a molecular weight of 150 to 3,000 and a solubility parameter (.delta., at 25.degree. C.) of 7 to 10 (cal/cm.sup.3).sup.1/2, to form a dispersion.
- (ii) cooling said dispersion until ethylcellulose separates out from said dispersion to form coating walls on said particles of said core material to form microcapsules, and then
- (iii) recovering said microcapsules from said dispersion.
Dependencies are inferred from the claim text.