Note: Descriptions are shown in the official language in which they were submitted.
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WATE;R TREATM~NT BLEND IN SOLID FOE~M
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Compositions which release chlorine into aqueous
~ media have been ~ound to be generally useful, such as
; for pr~paring a sterilizing solution~ For example it
-~ has been taugh~ in U.S. Patent No. 4,134,0Z4 to
sterilize an article at a temperature below that of
boiling water with a sterilizing solution having active
chlorine. A variety o~ ingredients havP been proposed
for such a sterilizing solution. These ingredients
include hypochlorite salts, toluene
sulfochloroamide compounds, chlorine dioxide,
chlorinated hydantoin, and trichloroisocyanuric acid and
;~ salts thereof.
Chloxine-containing compositions may also be
utili~ed for treatment o~ specific media, e.g.,
swimming pools. In such use, compounds can be provided
in a dispenser and the chemicals for water treatment
thereby dispensed to the swimming pool.
Suitable chlorine donor chemicals that have been
disclosed, e.gO, in British Patent NOr 1,327,763,
include the chlorocyanuric acids, calcium hypochlorite
and the halogenated hydantoins. It has also been known
to provide a chemical dispenser of disinfecting agent
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for a toilet tank. As disclosed in U.S. Patent No.
4,709,423 such a dispenser for providing a disinfactant
solution may contain a disinfectant such as halogenated
hydantoin, trichloroisocyanuric acid, and inorganic
hypochlorite salts, e.g., the salts of calcium, lithium
and magnesium.
Compositions providing available chlorine may also
be useful in dishwasher detergent compositions. Thus
there has been disclosed in U.S. Patent No. 4,284,524 a
cleaning composition for automatic dishwashers, which
composition can contain available chlorine at a level of
from about 0.5 to about 3 percent. To provide the
available chlorine, there may be used chlorinat:ed
trisodium phosphate as well as other materials such as
chloroisocyanurates, chlorinated hydantoin, toluene
sulfodichloroamides, hypochlorite salts, chlorinated
melamine, chlorinated succinimide, or N-chloroacetyl
urea and the like.
It has usually been proposed to provide various
blends or mixtuxes of ingredients for thesa specific
treating composition. For example U.S. Patent No.
4,709,423 recommends a mixture of trichloroisocyanuric
acid plus cyanuric acid. British Patent No. 1,327,763
recommends a mixture containing cyanuric acid or salt
thereo~. U~S. Patent No~ 3, 629,408 discloses a
combination of hypochlorite salt with a chlorinated
glycoluril.
It would however still be desirable to provide a
disinfectant composition that combines a great variety
of desirable charactaristics, e.g., economy of
manufacture, enhanced disinfectant quality and
controlled dissolve rate.
SUMMARY OF THE~ E~
There has now been devised a water treatment
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composition, in solid form, having much sought after
disinfection characteristics for aqueous media. If
desired, the composition will provide prolonged,
controlled dissolve rate to such media. Moreover, the
composition can exhibit viricidal properties in use,
combined with extended shelf stability before use. The
composition furthermore has suitable low toxicity in
handlingt stoxage and use.
In one aspect, the present invention is directed to
a new composition of matter comprising a solid
composition in the form of particles blended together of
one or more alkali metal or alkaline earth metal
hypochlorite with one or more N-halogenated
dialkylhydantoin. A particularly preferred blend is
calcium hypochlorite with 1-bromo-3-chloro-5,5-
dimethylhydantoin.
In anothex aspect the invention is directed to the
method of treating an a~ueous media to provide available
chlorine to such media.
2 0 DESCRIPTION OF THE PREFERRED EMBODIMI~NTS
The composition of the present inv~ntion can be
used for treating a variety of fluid media. For example
in water txeatment, it may be used generally to provide
available chlorine to media containing biologically
active components such as bacteria and viruses, e.g., it
may be utilized for treating aqueous sewage rnedia, plant
effluent, cooling towers, lagoons and secondary water
recovery. The composition can also be used for
specialty water treatment, e.g., in swimming pools. In
general, the composition w.ill be utilized ~or providing
available chlorine to media for bleaching, steri.lizing
and disin~ecting appllcations.
The composition will provide available chlorine to
the media to be treated. It is to be understood that
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the composition might not only dispense available
chlorine, but may also provide bromine. Whether the
composition provides chlorine or bromine or both, for
purposes of convenience, unless otherwise expressly
detailed, this will be referred to hereinafter simply as
available chlorine. It will thereby be understood that
when the word "halogen" is used herein, such will refer
to chlorine, bromine, or bo-th.
The available chlorine is expressed as the amount,
as a percentage, of the halogen, i.e., chlorine or
bromine or both, that is available based upon the total
of such halogens present in the solid composition. This
availability may be determined by titration of an
aqueous solution of the composition, such as with sodium
thiosulphate. This available chlorine may therefore
also be referred to as titratible chlorine. Although
providing a high degree of available chlorine, the
composition of the present invention has a most
desirable low toxicity. Yet it will nevertheless
provide excellent disinfection as well as viricidal
characteristics while providing for bacteriological
stabilization of aqueous media.
The hypochlorite, which may also be referred to
herein as the hypochlorite salt, will be an alkali metal
or alkaline earth metal hypochlorite. The metal of the
salt will most often be sodium, potassium, lithium,
calcium or magnesium. Mixtures of these salts may also
be used, such as mixtures includin~ alkali metal plus
alkaline earth metal salts, e.g., lithium hypochlorite
mixed with calcium hypochlorite. Preferably for economy
of the composition as well as efficiency of available
chlorine, the hypochlorite salt will simply be calcium
hypochlorite. In the blended, solid composition the
hypochlorite salt can be expected to provide from about
65 to 75 percent available chlorine, or about 55 to 75
percent available chlorine in the composition.
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The hydantoin used will be an N-halogenated
dialkylhydantoin. The halogen for this hydantoin will
be one or more of chlorine or bromine. For example,
there may be used 1-bromo-3-chloro-5,5-dimethylhydantoin
(which may be referred to hereina:Eter simply as
"BCDMH"). Advantageously for economy, the alkyl of the
dialkylhydantoin will be either or both of methyl or
ethyl. For example there may be supplied as the
hydantoin 1,3-dichloro-5-ethyl-5-rnethylhydantoin. The
hydantoin used can be expected to provide from 4~ to 72
percent available chlorine or about 0.5 to 18 percent
available chlorine in the composition as either bromine
or chlorine or both. In addition to the hydantoins
mentioned above, other suitable compounds that may be
used include 1,3-dibromo-5,5-dimethylhydantoi.n and 1,3-
dichloro-5,5-dimethylhydantoin. Additionally, mixtures
of hydantoins may be utilized in the composition. For
example a mixture containing a minor amount of 1,3-
dichloro-5-ethyl-5-methylhydantoin may be useful where
the major portion of the mixture is supplied by 1,3-
dichloro-5,5 dimethylhydantoin~ It is to be understood
that for economy the hydantoins that will be used will
most always be the commercially available materials that
can range from about 90 to more than 99 percent active
ingredient, with a balance typically of incidental
inerts. Preferably for efficient dispensing of
available chlorine, the hydantoin used will be BCDMH.
The hypochlorite salt may be available in powder or
flake form. However, other particulate, solid form,
e.g., granules, can be particularly serviceable,
especially where such are comminuted prior to use.
Usually, for blending with the hydantoin, the
hypochlorite salt will be a free-flowing particulate
having particle size within the range from about 12 to
about 100 mesh. Hypochlorite salt more finely divided
than about 100 mesh can lead to problems such as dusting
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when blending with the hydantoin. Salt particles of
greater size than abou~ 12 mesh will most always detract
from obtaining a uniform blend of the solid
particulates. Preferably, for best blending the
hypochlorite salt will be a granular material having a
particle size within the range of from about 16 mesh ko
about 40 mesh.
The hydantoins are usually commercially available
as dry, free-flowing solids in powder or granular or
flake form. Typically, as with the hypochlorite salts,
the hydantoin will be in granular form and will have
particle slæe from about 12 to 100 mesh. For initiating
preparation of the composition, as with the hypochlorite
salt, it is preferred to start with a hydantoin in
granular form, e.g., to avoid dusting during blending.
- In preparing the composition, there will be used
from 75 to 99 weight percent of the hypochlorite salt
and from 1 to 25 weight percent of the hydantoin, basis
100 weight percent of these ingredients. UsP of less
than about 75 weight percent of the hypochlorite salt
will be insufficient for providing desixeable available
chlorine. On the other hand, less than about 0.9 weight
percent of hydantoin will be insufficient to provide
beneficial effect from the hydantoin. These materials
in finely divided form, e.g., as granules, can then be
brought together by any mixing means, preferably by
mechanical mixing means which are typically utilized for
forming blends of dry ingredients. These may include,
for example, stirring and tumbling means or the like.
It is advantageous that mixing be carried out in such a
manner that the particle size of the ingredients being
mixed is not appreciably altered during the mixing of
the dry materials. A preferred dry blending operation
is accomplished with a ribbon blender. Particularly
where the blending is initiated with ingredients in very
finely divided form, and the blending operation is to
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form granules of the ingredients in mixture, the~e may
be utili~ed a granulating operation, e.g., roller
compacting of a moistened ingredient mix followed by
granulating. By any manner of blending there will
result a solid, particulate composition which will
typically have a highly desirable shPlf stahility on
storage, e.g., as a packaged blend of particulate
solids. In use, the particles may for example be simply
mixed with a liquid medium for desired treatment, or the
liquid can flow by, e.g., through or over, the solid,
water treatment blend particles.
It is to be understood that there may be present in
the composition additional ingredients, such as binding
agents, surface active agents, and the like.
For a representative composition there was blended
together a commercial grade, granular calcium
hypochlorite having a particle size between 16-40 mesh
and containing 72-75 percent available chLorine. With
this calcium hypochlorite there was blended a
commercially available, 1-bromo-3-chloro-5,5-
dimethylhydantoin ~BCDMH). This commercial BCDMH was
93.5 percent active ingredient, with a balance of
incidental inerts, having about 59 percent available
chlorine and was a granular material having particle
size between 12-40 mesh. The blending was done for
about 10 minutes in a double spiral blade ribbon
blender. The resulting blend was a white granular solid
and contained 5 weight percent BCDMH and 95 we:ight
percent calcium hypochlorite, the water having been
essentially volatilized during the blending operation.
This solid granular composition was 70 percent minimum
active halogen, expressed as available chlorine. The pH
of a 1 percent solution of this solid, granular mixture,
as determined by dissolving 1 gram of the blend in 100
milliliters of deionized water, was 9.15 at 20 C.
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