Low-viscosity radiation-curable composition for making an earpiece

A biocompatible, low-viscosity, radiation-curable composition, for producing antimicrobial medical products, in particular earpieces, by means of positive-negative-positive production methods or stereolithography, containing:

• a) 20-75 wt. % of one or a plurality of monomeric/oligomeric urethane(meth)acrylates having an acrylate functionality of <4, viscosity <30 Pa s, and molecular weight <3500;
• b) 5-45 weight % of a monomeric or oligomeric dimethacrylate of bisphenol A or bisphenol F and or of a monomeric aliphatic or cycloaliphatic di(meth)acrylate having a viscosity <6 Pa s;
• c) 2.5-25 weight % of a cross-linking monomeric or oligomeric component, wherein the component contains 4 methacrylate and/or acrylate functionalities;
• d) 0-15 wt. % of one or a plurality of monofunctional (meth)acrylates;
• e) 0.01-5 wt. % of one or a combination of antimicrobial additives selected from the group consisting of antimicrobially active glass fillers and silver particles;
• f) 0.5-6 wt. % of one or a plurality of photoinitiators whose absorption is in the wavelength range of an ND:YVO4 laser beam used or of an actinic radiation source used to promote free radical formation;
• g) 0-0.5 wt. % of one or a plurality of anaerobic inhibitors;
• h) 0-10 wt. % fillers;
• I) 0-5 wt. % coloring agents;
• and
• j) 0-5 wt. % conventional additives selected from the group consisting of ultraviolet stabilizers and flow agents, the proportion of components a) through j) together equaling 100 wt. %.