CA1230280A

CA1230280A - Method and tablet for sanitizing toilets

Info

Publication number: CA1230280A
Application number: CA000462502A
Authority: CA
Inventors: George D. Nelson; Steve Vazopolos
Original assignee: Monsanto Co
Current assignee: Monsanto Co
Priority date: 1983-09-06
Filing date: 1984-09-05
Publication date: 1987-12-15
Also published as: AU3274084A; AU559310B2; JPS6079100A; JPH0524960B2; BE900498A; NZ209469A

Abstract

METHOD AND TABLET FOR SANITIZING TOILETS
ABSTRACT
Disclosed is a tablet for disinfecting flush toilets comprising from about 20% to about 90% alkali metal salt of dichloroisocyanuric acid and at least about 5% of either sodium bromide or potassium bromide.
Also disclosed is a method of using the tablet.

Description

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METHOD AND TABLET FOR SAN TIZING_TOILETS
FIELD OF THE INVENTION
This invention relates to sanitizing and disinfecting flush toilets. More particularly, this invention relates -to automatic toilet bowl cleaners.
BACKGROUND
A number of different compositions and methods for disinfecting flush toilets have been proposed. These include various hypochlorite and lo chloramine compounds, that can be dispensed from a single-compartment dispenser, such as is described in US. Patent 4,318,891, or from a two-compartment dispenser such as is described in US. Patent 3,618,143 or 4,208,746. The disinfecting composition can be employed as granules, but is more commonly employed as a tablet.
In order to act effectively in automatic toilet bowl cleaners, the disinfectant tablet must have a number of properties. The tablet should produce a disinfectant concentration from Abbott 2 to about 30 parts per million, preferably from about 5 to about 20 parts per million, per flush. The tablet must not produce objectionable chloramine or other objectionable odors. The tablets must retain their integrity throughout the useful life of the toilet bowl cleaner and must not crumble or disintegrate so as to plug the various holes and passages in the dispenser, through which water is circulated as the toilet -tank fills and drains.
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The most commonly used disinfectant tablet materials are calcium hypochlorite and trichloroiso-cyan uric acid. Each of these substances has major drawbacks. Calcium hypochlorite contains insoluble components that can plug the holes in the dispenser, and also contributes to water hardness and scale format lion by adding calcium ions to the water. Trichloroiso-cyan uric acid is a strong acid and can produce objection-able chloramine odors under some circumstances.
A disinfectant tablet that produces an appropriate concentration of disinfectant, with the requisite lifetime and tablet integrity and without the negative properties discussed above would be an advance-mint in the art.
SUMMARY OF THE INVENTION
The invention provides a tablet for disinfect-in a flush toilet with from about 20% by weight to about 90% by weight of an alkali metal salt of dichloro-isocyanuric acid and at least about I by weight of bromide salt selected from the group consisting of sodium bromide and potassium bromide. The preferred alkali metal salts of dichloroisocyanuric acid are sodium and potassium, with sodium being preferred.
Particularly preferred is sodium dichloroisocyanuric acid dehydrate. The tablet may, optionally, contain trichloroisocyanuric acid, but, the amount of available chlorine in the tablet should be less than about 70%, or additional measures must be taken to avoid production of objectionable quantities of chloramine odors. The tablet may also contain one or more mold release agents or other tabulating aids to assist in forming the tablets The tablet may also contain an inert filler.
A particularly preferred embodiment is a tablet with from about 50% by weight to about 75% by weight of sodium dichloroisocyanuric acid dehydrate, from about I
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5% by weight to about 15% by weight of potassium brow mode, from about 10~ to about 40% sodium chloride, and from about 1% to about 5% mold release agent or agents.
Another particularly preferred embodiment is a tablet with from about 20% by weight to about 52% by weight sodium dichloroisocyanuric acid dehydrate, from about 18% by weight to about 47% by weight potassium bromide, from about 0% by weight to about 60% by weight sodium chloride, and from about 1% by weight to about 5% by weight mold release agent, where the ratio of sodium dichloroisocyanuric acid dehydrate to potassium bromide is substantially stoichiometric. This invention also provides a method for disinfecting a flush toilet by placing a tablet as described above in contact with all or a portion of the water provided to flush the toilet, particularly where the water is contained in a tank that is part of the toilet.

DESCRIPTION OFT INVENTION
This invention produces the balance of proper-ties for a good toilet bowl disinfectant by combining either sodium or potassium bromide with an alkali metal salt of dichloroisocyanurate, such as sodium dichloro-isocyanurate or potassium dichloroisocyanurate. Trip chloroisocyanurate can be used as part of this invention, however, the amount of available chlorine in the forum-lotion should be below about 70% to minimize the posse-ability of generation of objectionable chloramine odors, which can be produced by trichloroisocyanurate.
Chloramine odors can also be minimized by other methods, such as addition of an alkaline component to maintain the pi of the water strongly alkaline, preferably above about pi 9. Trace levels of chloramine can be accept-able as they are often identified as a "chlorine odor"
that is associated with cleanliness, however, high I
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levels of chloramine odor are considered to be very objectionable. This possibility of generation of objectionable chloramine odors represents a serious drawback to use of compositions containing trichloro-isocyanurate as the only active ingredient.
Similarly, the use of alkali metal salts ofdichloroisocyanurate as the only active ingredient in toilet bowl disinfection applications has serious draw-backs. These salts are substantially more soluble than trichloroisocyanurate, and as a result tablets do not - last long enough to be commercially acceptable.
However, the problems associated with use of alkali metal dichloroisocyanurates can be eliminated by addition of sodium bromide or, more preferably, potassium bromide to the composition. The bromide salt must comprise at least about I by weight of the composition, preferably at least about 10~. The brow mine salt accomplishes this modification in the properties of the composition by a reaction between the alkali metal salt of dichloroisocyanuric acid and the bromide salt to replace some or all of the chlorines by bromides. The properties of the composition continue to improve as the proportion of bromide salt is increased, with optimum properties observed when the bromide salt and alkali metal salt of dichloroisocyanuric acid are present in substantially stoichiometric amounts.
The bromide salt can be present in greater than stoichiQmetric amounts because it also acts as a filler.
But, because the bromide salt is more expensive than alternative fillers, there is an economic incentive to use the minimum quantity of the bromide salt that will produce the desired results.
The alkali metal salt of dichloroisocyanurate can be either sodium or potassium dichloroisocyanurate, with sodium being preferred. Most preferred is sodium .~2~3C~'~ !30 I AYE
dichloroisocyanuric acid dehydrate. The alkali metal salt of dichloroisocyanuric acid is used from about 20%
to about 90%~ or more preferably from about 50% to about 75% by weight of the tablet.
It is also possible to include trichloroiso-cyan uric acid in the formulation. In order to avoid objectionable chloramine odors, the amount of avail-able chlorine in the tablet should be less than about 70%, or other muzzlers should be taken to avoid generation of chloramine odors. The term "available chlorine" is a commonly used term meaning the amount of active chlorine by weight in the composition, come pared with the amount of active chlorine by weight in chlorine gas, expressed as a percent. As used herein "available chlorine" also includes active chlorine that is replaced by bromide, since bromide atoms replace chlorine atoms on a one for one basis.
It is also possible for the formulation to include a filler. The filler is an inert substance that can be used to assist in tablettability of the composition, to adjust concentration of the components, to reduce cost, or for other reasons. The filler can be used in any concentration, provided the composition contains the required amount of alkali metal salt of dichloroisocyanuric acid, and provided the composition contains at least about 5% of the bromide salt. The filler is preferably present from about 10% to about 40%. The most common filler is Nail.
In addition to the components of the formula-lion described above, the formulation may also contain other ingredients, such as tabulating aids, e.g., mold release agents, binders, etc.; corrosion inhibitors, scale inhibitors, and other components known to one skilled in the art. Preferred mold release agents are boric acid and monoglyceryl Stewart. It is preferred that one or more mold release agents be present from about 1% to about 5% or more. Tablets are formed in the usual manner.

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It is preferred that all of the components of the formulation be fully hydrated, to avoid hydration after tabulating, which can be detrimental to tablet integrity.
The tablet of this invention can either be used alone to provide only disinfection, or can be used as part of a two tablet system to provide more complete cleaning. The second tablet in a two tablet system may contain a detergent, a surfactant, a perfume, a corrosion inhibitor, a scale inhibitor and a dye, and possibly other ingredients. It is preferred that this invention be used as part of a two tablet system.
It is preferred that this invention be used in a dispenser so that the tablet is immersed or par-tidally immersed in water within an enclosure in which the reaction between the bromide salt and the alkali metal salt of dichloroisocyanurate can occur. Part-ocularly preferred are dispensers similar to those described in US. 3,618,143 or US. 4,208,747 However, this invention can be used with other dispensers either in the tank or as part of an "under the rim" toilet bowl cleaner.

The following Examples are intended to thus-irate this invention and are not intended in any way to limit its scope. In the Examples, as well as the discussion above, all parts and percentages are by weight unless otherwise specified.

In each of Examples 1 - 6, 1.75 inch (3.8 cm.) tablets were prepared in a hydraulic press at 9100 -9800 psi (62,700 - 67,500 spa) of pressure, using 33 g of each of the following formulations:
Example 1 - 94% trichloroisocyanurate, 5%
sodium bromide, 1% boric acid, and 0.5~ monoglyceryl Stewart.

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Example 2 - 62% trichloroisocyanurate, 32%
potassium dichloroisocyanuric acid, 5% sodium bromide, 1% boric acid, and 0.5~ monoqlyceryl Stewart.
Example 3 - 33% trichloroisocyanurate, 33%
potassium dichloroisocyanuric acid 33% potassium brow mode, 1% boric acid, and 0 5% monoglyceryl Stewart.
Example 4 - 48% sodium dichloroisocyanuric acid dehydrate, 48% sodium chloride, 2% potassium bromide, 1% boric acid, and 0.5% monoglyceryl Stewart.
Example 5 - 56% sodium dichloroisocyanuric acid dehydrate, 37% sodium chloride, 5% potassium bromide, 1% boric acid, and 0.5% monoglyceryl Stewart Example 6 - 64% sodium dichloroisocyanuric acid dehydrate, 32% sodium chloride, 2% potassium bromide, 1% boric acid, and 0.5% monoglyceryl Stewart.
All of the compositions formed good tablets.
Each of the tablets was placed in a dispenser similar to that described in US. 4,208,747. The dispenser was placed in a container of water and periodically was raised out of the water to simulate flushing action in a toilet.
The amount of disinfecting halogen (chlorine and bromide) was determined amperometrically. From these data, the concentration of halogen (expressed as parts per million chlorine) dispensed to an average toilet was estimated. This procedure was repeated for each of the Examples so that the lifetime of each of the tablets could be estimated. The results, along with the available chlorine for each of the formulations are included in Table I.

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TABLE I
En. % Available Halogen Concentration Estimated Tablet No. Chlorine Range in Toilet (Pam Life (Days) Chlorine) .. _ . . .. .
1 84.2 1.4 - 5 30-~
2 74.4 2~0 4 30+

3 42.9 0.8 - 4 30

4 26.8 4.2 -12 4 31.0 2.0 - 8 30 6 35.8 8.0 -15 7 Examples 1 and 2 both produced objectionable chloramine odor. Each of the tablets maintained its integrity throughout the test with no problems with clogging of the passage in the dispenser. Each of Examples 4 and 6, which contained only 2% potassium bromide resulted in very short lifetimes, showing the volubility of the sodium dichloroisocyanuric acid dehydrate. Example 5, with 5% potassium bromide showed a marked increase in lifetime, demonstrating the remarkable effect of this invention. Both Examples 3 and 5, within the scope of this invention produced very good results with adequate disinfectant concentration, good lifetime, good tablet integrity, and no objection-able chloramine odor.
Examples 7 - 10 In Examples 7 - 10, 50 g tablets of similar diameter to those of Examples 1 - 6 were prepared in a similar manner, using the following formulations;
Example 7 - 56% sodium dichloroisocyanuric acid dehydrate, 37% sodium chloride, 5% potassium bromide, 1% boric acid, and 1% monoglyceryl Stewart.
Example 8 - 61% sodium dichloroisocyanuric acid dehydrate, 30~ sodium chloride, 5% potassium brow mud 1% boric acid, and 1% monoglyceryl Stewart.
Example 9 - 51% sodium dichloroisocyanuric acid dehydrate, 47% potassium bromide, 1% boric acid, and 1% monoglyceryl Stewart.

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Example 10 - 73% sodium dichloroisocyanuric acid dehydrate, 10% sodium chloride, 15% potassium bromide, 1% boric acid, and 1% monoglyceryl Stewart.
In Example 9, the amount of potassium bromide is approximately the stoichiometric amount required to convert all of the sodium dichloroisocyanuric acid to potassium dibromoisocyanuric acid. Each of the tablets was placed in a dispenser similar to that used in Examples 1 - 6 and place din the tank of a standard flush toilet that was rigged to slush approximately hourly.
Water samples were taken periodically and analyzed as in Examples 1 - 6, and tablet life was determined. The results are reported in Table II.
TABLE II
_ Example Halogen Concentration Tablet Life Number Range (Pam Chlorine Flushes 7 2 - 8 >300 Each of Examples 7 - 10 performed well and did not clog the passages in the dispenser. Assuming approximately 10 flushes per day, each of the tablets would be expected to last about 30 days or more.
In addition to altering the composition of the tablets, it is also possible to fine tune the performance of a tablet by altering its size or shape, or by alter-in the tabulating pressure, or other tabulating changes known to one skilled in the art One skilled in the art will understand and appreciate that various changes or alterations can be made in the Examples above, without departing from the spirit or scope of this invention.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A tablet suitable for disinfecting flush toilets comprising: from about 20% by weight to about 90% by weight of an alkali metal salt of dichloroiso-cyanuric acid and at least about 5% by weight of bromine salt selected from the group consisting of sodium bro-mide and potassium bromide.

2. A tablet of Claim 1, further comprising a mold release agent.

3. A tablet of Claim 1, further comprising trichloroisocyanuric acid.

4. A tablet of Claim 1 further comprising an inert filler.

5. A tablet of Claim 1 in which the alkali metal salt of dichloroisocyanuric acid is sodium di-chloroisocyanuric acid dihydrate.

6. A tablet of Claim 1 in which the bromine salt is potassium bromide.

7. A tablet suitable for disinfecting a flush toilet, comprising a. from about 50% by weight to about 75% by weight of sodium dichloroisocyanuric acid dihydrate;
b. from about 5% by weight to about 15% by weight potassium bromide;
c. from about 10% by weight to about 40% by weight sodium chloride; and d. from about 1% by weight to about 5% by weight mold release agent.

8. A tablet suitable for disinfecting a flush toilet, comprising from about 20% by weight to about 52% by weight sodium dichloroisocyanuric acid dihydrate, from about 18% by weight to about 47% by weight potassium bromide, from about 0% by weight to about 60% by weight sodium chloride, and from about 1% by weight to about 5% by weight mold release agent, in which the ratio of sodium dichloroisocyanuric acid dihydrate to potassium bromide is substantially stoichiometric.

9. A method or disinfecting a flush toilet, comprising placing the tablet of Claim 1 in contact with water provided to flush the toilet.

10. The method of Claim 9 wherein the water provided to flush the toilet is contained in a tank.

11. A method for disinfecting a flush toilet, comprising placing the tablet of Claim 7 in contact with water provided to flush the toilet.

12. The method of Claim 11 wherein the water provided to flush the toilet is contained in a tank.

13. A method for disinfecting a flush toilet, comprising placing the tablet of Claim 8 in contact with water provided to flush the toilet.

14. The method of Claim 13 wherein the water provided to flush the toilet is contained in a tank.