The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 10, 2003
Filed:
Jul. 30, 2001
Hans-Ulrich Petereit, Darmstadt, DE;
Thomas Beckert, Darmstadt, DE;
Manfred Assmus, Bickenbach, DE;
Werner Hoess, Heusenstamm, DE;
Wolfgang Fuchs, Alsbach, DE;
Hartmut Schikowsky, Darmstadt, DE;
Roehm GmbH & Co. KG, Darmstadt, DE;
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 the mold cavity has a temperature which lies at least 10° C. below the glass transition temperature of the (meth)acrylate copolymer, cooling of the melt mixture and removal of the obtained molded article from the mold.