DuPont Oxone®
Monopersulfate Compound Applications

• Denture Cleansers
• Paper Recycling
• Printed Circuit Board Etching
• Laundry Bleach
• Shrinkproofing Wool
• Environmental Applications

The high oxidation potential of Oxone® is useful in a wide variety of products and processes, especially those in which the convenience of a solid product is required. Oxone® can be blended with many additives; however, all ingredients used with Oxone® must be anhydrous or must hold hydrated water tightly; stability testing of each blend is essential.

Since Oxone® is acidic, it is usually blended with sufficient alkaline salts to buffer it to near-neutral or slightly alkaline pH when compounded into cleaners.

Denture Cleansers
Denture cleanser formulations containing at least 25% Oxone® provide excellent decolorization of food and other organic stains. Formulations usually include sodium perborate monohydrate, sodium carbonate and/or bicarbonate, and may also include citric acid, EDTA or DTPA chelants, flavor/fragrance, and food color. Cleansers are often tabletted, but may be delivered in granulated form as sachets. The long shelf life of these products requires moisture barrier packaging materials such as a metal or plastic tube or a heat-sealed wrap of flexible reverse printed polyester laminated to foil which is extrusion coated with a sealant layer of Surlyn® ionomer resin.

Paper Recycling
Oxone® is a convenient and effective processing aid for repulping internal broke or a secondary fiber furnish*. Paper products containing polyimine/polyamide wet strength resins can be effectively repulped to make the same grade paper. Oxone® use has been demonstrated on a variety of sanitary, food, packaging, and specialty papers containing wet strength resin and made from different furnishes.

Unlike chlorine-based repulping agents, Oxone® does not produce absorbable organic halogens (AOX) or other chlorinated organics. It also does not degrade the fiber or darken mechanical pulp. It is easier to handle and does not require any additional storage or delivery equipment. Under optimum conditions, Oxone® reacts rapidly, thereby reducing the repulping time and increasing the productivity of the pulper. It is effective under commonly found pulping conditions.

Oxone® can also be used to repulp certain colored papers, including decolorization of dyes. Dye destruction generally requires use of an additional reactant which is added to the repulper separately.

Oxone® can be delivered to the repulper either in specially designed repulpable bags or by using an automated system fed from a bulk bag of Oxone®. Either method can provide accurate dosing to the repulper and minimizes handling by operating personnel.

* Pankaj C. Kapadia, "A Non-Chlorine Repulping Aide", 1992 TAPPI Papermaker's Conference Book of Papers.

Printed Circuit Board Etching
Oxone® is used as a microetchant for cleaning and preparing copper printed wiring board surfaces. The superior etching performance of Oxone® is useful in plated-through-hole production in pattern and panel plating, inner layer bonding, and prior to photoresist or solder mask application. This microetchant is used in both dip and spray cleaning of inner layer copper surfaces, and results in a sharply defined etch with greatly expanded surface area to assist in pre-lamination, pre-oxide, and pre-plating operations. Etch rates from 0.25 - 2.5 µm/min (10 - 100 µin/min) can be obtained by varying the Oxone® concentration, acid concentration, and temperature.

Oxone® offers advantages over other mild etch solutions in etch rate control, consistency of etch rate over a long period of time, and in waste treatment.

Wool Shrinkproofing
Oxone® is used as an oxidizer for the treatment of wool to prepare it for the application of shrinkproofing resins. In this application, Oxone® disrupts the surface of the wool and oxidizes cystine linkages in the cuticle to give it anionic character which is ideal for attracting polyacrylic and polyamide resins, with less damage to the wool than chlorine processing, and without the environmental damage associated with chlorine use.

Laundry Bleach
Oxone® is an effective low-temperature non-chlorine laundry bleach when formulated to provide at least 25 ppm of active oxygen in the wash water. Conventional anhydrous alkalis and fillers can be used to attain a pH of 9 - 10, and to control dose. Oxone® can be used with colors; however, care must be taken to completely dissolve Oxone® before contact with damp fabrics to avoid dye damage.

Environmental

Oxidation of Reduced Sulfur
Oxone® can be used to oxidize hydrogen sulfide (H₂S) in waste streams. This provides a convenient method of de-odorizing a waste stream (or stack via scrubbing) without the necessity of on-site manufacture or handling of hazardous chemicals such as Caro's acid. Other reduced sulfur compounds, such as mercaptans, sulfides, disulfides, and sulfites may also be oxidized. Analytical testing must be used to determine the effect on the waste stream.

Oxidation of Cyanide
Cyanide in waste streams from metal plating or mining operations can be oxidized rapidly using Oxone®. For dilute or small volume waste streams, an Oxone® -based waste treatment process can be convenient and economical.