Injection molding method for (meth)acrylate copolymers having tertiary ammonium groups

US6576255B1 · kind B1 · utility

Assignee

• ROEHM GMBH & CO. KG · DE

Inventors

• Hans-Ulrich Petereit · Darmstadt, DE
• Thomas Beckert · Darmstadt, DE
• Manfred Assmus · Emmelshausen, DE
• Werner Hoess · Griesheim, DE
• Wolfgang Fuchs · Echterdingen, DE
• Hartmut Schikowsky · Darmstadt, DE

Key dates

• Filing date: Jul 30, 2001
• Grant date: Jun 10, 2003
• Expiry date: Jul 31, 2021

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61J3/071
• WIPO field: Pharmaceuticals
• WIPO sector: Chemistry

Abstract

The invention relates to a process for making molded articles by means of injection molding with the process steps of a) melting of a (meth)acrylate copolymer, which is composed of 30 to 80 wt % of radical-polymerized C1 to C4 alkyl esters of acrylic or methacrylic acid and 70 to 20 wt % of (meth)acrylate monomers with a tertiary ammonium group in the alkyl residue, wherein the (meth)acrylate copolymer is present in a mixture with 1 to 70 wt % of a plasticizer and a desiccant in the ratio of 1:1 to 1:20 and also with 0.05 to 5 wt % of a release agent, and further standard additives or adjuvants and if necessary even a pharmaceutical active principle can also be present in the mixture, and before the mixture is melted it has a content of more than 0.5 wt % of low-boiling constituents with a vapor pressure of at least 1.9 bar at 120° C., b) degassing of the mixture in the thermoplastic condition at temperatures of at least 120° C., whereby the content of low-boiling constituents with a vapor pressure of at least 1.9 bar at 120° C. is lowered to at most 0.5 wt % and c) injection of the melted and degassed mixture into the mold cavity of an injection-molding die, wherein th…