Industries and Applications for AGXX

Polymers are used in a wide variety of applications. Due to the large number of applications, the polymers must also have a wide variety of capabilities to function properly in the respective applications. For example, antimicrobial efficacy is also elementary in many areas to protect the material from microorganisms. Polymer applications that benefit greatly from antimicrobial capabilities include food conveyor belts, wound dressings, mattresses, films and many more.

AGXX represents the optimal technology for polymer applications, as the antimicrobial technology provides the material with sustainable antimicrobial properties.

Due to its innovative mechanism of action, AGXX shows excellent efficacy in water-absorbent polymers such as polyamide 6 types and polyurethanes. Its efficacy has been proven by tests conducted by Heraeus' partners.

In addition to polyamides, AGXX was incorporated into PU flexible foam at different concentrations. After incorporation, antimicrobial efficacy tests and material tests were conducted with the equipped flexible foams. The antimicrobial particles can be easily incorporated into the foam and distributed homogeneously without affecting the foam structure of the polyurethane. To investigate the antimicrobial activity of the material, standardized ASTM E2149 tests were carried out, whereby the foam bodies were incubated in bacterial suspensions for 24 hours and the germ reduction was determined hourly. Here, testing was performed against E. coli and S. aureus strains.

Microorganisms feel very comfortable on textiles. Everyone knows the unpleasant smell of laundry after sports. The trigger for this odor is not the sweat itself, but bacteria that decompose the sweat. While odor triggered by microorganisms causes discomfort for the wearer and those around him, the presence of microorganisms on textiles is also a huge social problem. Because most hospital infections are transmitted via textiles, so microorganisms on textiles pose an enormous threat to people's health. AGXX makes it possible to provide textiles with long-term antimicrobial properties, even after multiple washing cycles. Thus, AGXX can help to reduce the number of hospital infections and save human lives.

In addition to this advantage, AGXX can also provide a remedy against unpleasant odors in the private sphere and thus ensure that users simply feel more comfortable in their clothing.

Various tests have shown that AGXX can be used to provide textiles with antimicrobial properties without any problems. AGXX can already be successfully incorporated into textile coatings and textile fibers.

In the field of textile coatings, AGXX particles were incorporated into hydrophilic as well as slightly hydrophobic PU-based systems. After incorporation, all samples were subjected to several washing cycles and subsequently tested for their antimicrobial efficiency. Standardized ISO 22196 tests for antimicrobial efficacy were performed.

As a result, both AGXX-containing samples showed excellent antimicrobial efficiency against the S.aureus bacteria used (germ reduction >99.9%), compared to the AGXX-free references.

The processability of the AGXX-additivated finishes was smooth and the AGXX had no influence on the properties of the coatings, such as dirt and scuff resistance.

The tests shown were carried out at the German Institute for Textile & Fiber Research (DITF) and were part of a feasibility study. Based on the successful results, the application of AGXX in textiles is being developed and investigated together with the DITF in a project publicly funded by the German Federal Ministry of Economics and Climate Protection. So that further textile finishes, coatings and incorporation into synthetic textile fibers will be investigated as part of the funded joint project. Initial tests on the incorporation of AGXX particles into nylon fibers on a laboratory scale have already shown promising results in terms of processability. Earlier trials by technology partner Largentec also demonstrated flawless antimicrobial efficacy of AGXX-additivated nylon fibers in ISO 20743 tests. Heraeus is continuously working on particle optimization to enable optimal incorporation into textile fibers. In addition to investigating the antibacterial and antiviral effect and processability of AGXX, the joint project with the DITF is also addressing questions relating to reprocessing processes, functionality, and the influence of various sterilization methods.

To demonstrate the functionality of AGXX as a film preservative, tests were carried out according to ISO 22196 against S.aureus and E.Coli strains. For this purpose, AGXX was incorporated into a biocide-free interior paint and into a biocide-free polyurethane lacquer. In the interior paint, AGXX showed excellent antimicrobial efficacy against both bacterial strains, while in the polyurethane lacquer, the antimicrobial technology showed excellent efficacy against the S.aureus strains and slight antimicrobial efficacy against the E.coli strains.

The efficacy is related to the material properties of the system, especially the water absorption capacity of the material.

In addition to the antimicrobial efficacy of a preservative, it is fundamental that the added additive does not distort the color fastness even over a longer period. To demonstrate the preservation of color fastness despite AGXX, accelerated weathering tests (QUV tests according to ISO 16474-3) were carried out. For this purpose, the AGXX-containing samples were stored in a weathering facility for 500 hours and subjected to weekly color evaluation in comparison with the AGXX-free reference. With the result that hardly any visual differences could be detected between the antimicrobial color and the reference.

In addition to protecting the filter itself, AGXX has already been tested in a laboratory-scale test setup for water filtration applications. For this purpose, two laboratory columns with a length of 200 mm and a diameter of 3.8 mm were filled with activated carbon granules with an average particle size of approximately 350 μm. The first column contained only AGXX-free activated carbon granules. The second column was filled with a mixture of 99 % AGXX-free granules and 1 % AGXX-coated activated carbon granules of the same type. Both columns were connected to a pump that simultaneously passed 150ml of E.coli suspension containing 0.4 ∙ 10⁶ colony forming units (CFU) through both columns at a flow rate of 1ml/min. After every 15 ml, 1 ml of the filtrate was taken, plated on agar, and analyzed for the number of CFU. The analysis showed that the number of bacteria in the filtrate of the AGXX-free column increased continuously. In contrast, the filtrate passed through the column with 1 % AGXX-coated granules was completely germ-free throughout the filtration experiment. This experiment demonstrates the high antimicrobial efficacy of AGXX in water filtration.