Bacteriostatic and fungistatic additive in masterbatch for application in plastics, and method for producing same

Abstract

Disclosed is an additive of ZnO / Ag° with a bacteriostatic and fungistatic action in the production of plastic items based on resins such as polypropylene, polyethylene, polystyrene, high-impact polystyrene, polyurethanes, etc., especially for producing automotive products, electrical appliances, products for washing, for storing and conducting water, for packaging, etc. The additive is prepared by mixing nanometric silver concentrates and pre-treated zinc oxide with a polymer resin compatible with the target application as a vehicle, obtaining pellets of the additive in a ratio of between 10:90 and 90:10 in weight of ZnO / Ag° : vehicle. The additive is biologically effective at a ratio in the final product of between 0.01 and 0.5 wt. % of polymer mixture and does not have any negative effects on other properties of the polymer, such as the whiteness thereof.

Description

TECHNICAL FIELD[0001]This invention refers to additives used in the plastics industry, particularly refers to an additive concentrate in the form of masterbatch with bacteriostatic and fungistatic activity manufactured by mixing a concentrate of nanoparticles of zinc oxide and a concentrate of metallic silver nanoparticles and a method for its manufactures.BACKGROUND OF THE INVENTION[0002]People have been concerned for a long time to protect themselves from germs that can cause disease, infections and growth of bacteria and moulds. The manufacture of articles with antimicrobial additives helps to increase the protection against these microbes. Many products containing antimicrobial additives exist, including soaps, lotions and disinfectants and environment refreshing products. These products are used to clean surfaces that may have germs on them, which offers some protection benefits but do not prevent microbes to settle back. In the field of health care, medical devices and dental ...

AI Technical Summary

Benefits of technology

The present invention relates to a method of creating an additive with bacteriostatic and fungistatic activity for use in plastic article manufacture while maintaining the desired properties of the material. The method involves using metallic silver and zinc oxide to provide an active surface with the additive, which can then be used in plastic processing techniques such as coextrusion, coinjection, and rotomolding for the production of plastic articles. The non-migration of particles in the additive ensures the desired properties of the material are not compromised.

Problems solved by technology

These products are used to clean surfaces that may have germs on them, which offers some protection benefits but do not prevent microbes to settle back.

The antimicrobial silver compound in contact with the polymeric article may interact with it producing undesirable effects, such as darkening due to reduction to metallic silver.

Furthermore, it is recognized that zeolite powders tend to agglomerate and are inferior in dispersibility when mixed with resins.

The difficulty to find such materials commercially lies mainly in the high cost of the quantities of metal and / or metal compounds necessary to achieve the desired purpose, particularly in the case of silver, as these substances should be included in the plastic in powder form, in which case the lower limit of efficiency of metal / metal compound is often established set in the order of 1% by weight of the plastic, being used however higher amounts to make it more effective.

Certain polymeric materials, for example polyvinyl chloride, are susceptible to biological attack, especially from fungi.

From the above examples, it can be seen that no efficient and inexpensive method, is already available to enable the production of plastic articles with antimicrobial properties, especially fungistatic and bacteriostatic, producing no adverse side effects.

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