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Method for molding capsules

  • US 4,591,475 A
  • Filed: 04/29/1983
  • Issued: 05/27/1986
  • Est. Priority Date: 03/26/1982
  • Status: Expired due to Term
First Claim
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1. The method of manufacturing a shaped product from a hydrophilic polymer and water mixture having no phase separation of the water from the hydrophilic polymer-water mixture at a water content of between about 5 and 25% by weight of the hydrophilic polymer and having a certain glass transition temperature range, comprising the steps of:

  • (a) mixing the polymer with water in a predetermined amount between about 5 and 25% by weight of the hydrophilic polymer;

    (b) heating the hydrophilic polymer with said water while maintaining said predetermined water content to form a melt;

    (c) further heating the hydrophilic polymer melt and water to a temperature to dissolve the melt in the water and achieve a homogeneous dispersion on a molecular level while maintaining said predetermined water content;

    (d) injecting the dissolved hydrophilic polymer melt into a mold cavity while maintaining said predetermined water content;

    (e) cooling the hydrophilic polymer melt in said mold to form a molded product at a temperature below the glass transition temperature range of the hydrophilic polymer while maintaining said predetermined water content; and

    (f) ejecting the molded product of said hydrophilic polymer from said mold.

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