Massive bodies containing free halogen source for producing highly converted thickened solutions of chlorine dioxide

Abstract

A massive body, e.g., a tablet, for producing a thickened solution of chlorine dioxide when the massive body is added to liquid water is disclosed. The massive body comprises a metal chlorite, an acid source and a thickener (incorporated directly into the massive body or added as a component separate from the massive body) and optionally a source of free halogen. The concentration of free chlorine in the solution will be: (a) less than the concentration of chlorine dioxide in said solution on a weight basis and the ratio of the concentration of chlorine dioxide to the sum of the concentrations of chlorine dioxide and chlorite anion in said solution is at least 0.25:1 by weight; or (b) equal to or greater than the concentration of chlorine dioxide in said solution on a weight basis and the ratio of the concentration of chlorine dioxide to the sum of the concentrations of chlorine dioxide and chlorite anion in said solution is at least 0.50:1 by weight.

Description

REFERENCE TO RELATED APPLICATION [0001] This application is a continuation-in-part of pending application Ser. No. 10 / 744,481 filed Dec. 23, 2003, which is a continuation of U.S. application Ser. No. 10 / 173,224, filed Jun. 17, 2002, now U.S. Pat. No. 6,699,404, which is a continuation-in-part of U.S. application Ser. No. 09 / 496,803 filed Feb. 2, 2000 now U.S. Pat. No. 6,432,322.BACKGROUND OF THE INVENTION [0002] Free molecular chlorine dioxide in solution is an effective agent for the control of microorganisms and biological film deposits. The most common way to produce such solutions of free chlorine dioxide is to use an expensive and complicated chemical generator (see for example U.S. Pat. No. 5,009,875). In most cases, solutions of chlorine dioxide are produced as unthickened, low viscosity liquid solutions that may be too fluid to adhere to and be effective on some substrates; particularly vertical substrates. [0003] British patent 608,068 teaches the use of organic acid anhydr...

AI Technical Summary

Problems solved by technology

As a result of the low conversion ratio produced by the compositions of this British patent, and the dangers inherent in compositions combining sodium chlorite and organic chemicals, the compositions of this British patent have received little commercial interest.

It is relatively expensive (due to the cost of the membrane and of assembly), and the rate of chlorine dioxide delivery can be too slow for certain applications.

Also, the device may float on the surface of the water / solution (due to entrapped air or chlorine dioxide gas), and this can result in the loss of some chlorine dioxide to the gas phase.

Removal of the spent membrane from the chlorine dioxide solution may, at times, be considered inconvenient.

Thus, it cannot be ascertained whether the inventor was attempting to, or indeed ever did, obtain an aqueous solution of chlorine dioxide when his briquette was contacted with water.

The conversion efficiency reported in the patent for the tablets is, for the most part, low.

Despite being effective for many different purposes, the unthickened, low viscosity and liquid consistency of many of these solutions limit the potential uses of the solution and often require concerted effort from a user to ensure the solution is being applied in an effective manner.

Furthermore, the limitations of using unthickened, low viscosity chlorine dioxide solutions are apparent when the solution is used in cleaning, sanitizing or disinfecting a surface or substrate, e.g. medical instruments.

However, this method of application also presents the problem where the liquid solution could splatter or drip on unintended areas and be ineffective on the desired area.

The spraying of unthickened, gaseous or liquid chlorine dioxide may also be insubstantial and require the user to make repeated spray-applications.