U.S. patent application number 12/581336 was filed with the patent office on 2010-10-21 for solid composition for treating water.
This patent application is currently assigned to CHEMTURA CORPORATION. Invention is credited to Michael J. Engram, David F. Purdy, Nidhi Rawat.
Application Number | 20100264361 12/581336 |
Document ID | / |
Family ID | 39312384 |
Filed Date | 2010-10-21 |
United States Patent
Application |
20100264361 |
Kind Code |
A1 |
Rawat; Nidhi ; et
al. |
October 21, 2010 |
SOLID COMPOSITION FOR TREATING WATER
Abstract
Solid water treatment compositions are provided comprising (a) a
halogen-containing source; (b) a boron-containing source; and (c) a
polyphosphate-containing source. Methods for their use are also
provided.
Inventors: |
Rawat; Nidhi; (Duluth,
GA) ; Purdy; David F.; (Decatur, GA) ; Engram;
Michael J.; (Dacula, GA) |
Correspondence
Address: |
Jaimes Sher;CHEMTURA CORPORATION
199 Benson Rd.
Middlebury
CT
06749
US
|
Assignee: |
CHEMTURA CORPORATION
Middlebury
CT
|
Family ID: |
39312384 |
Appl. No.: |
12/581336 |
Filed: |
October 19, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
11975574 |
Oct 18, 2007 |
7625496 |
|
|
12581336 |
|
|
|
|
60856422 |
Nov 3, 2006 |
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Current U.S.
Class: |
252/175 |
Current CPC
Class: |
C02F 1/76 20130101; C02F
1/50 20130101; C02F 2103/42 20130101; C02F 2103/023 20130101 |
Class at
Publication: |
252/175 |
International
Class: |
C02F 5/10 20060101
C02F005/10 |
Claims
1. A solid water treatment composition comprising (a) a
halogen-containing source; (b) a boron-containing source; and (c) a
polyphosphate-containing source.
2. The solid water treatment composition of claim 1, wherein the
halogen-containing source comprises one or more of a halogenated
triazinetrione, halogenated hydantoin, calcium hypochlorite and
lithium hypochlorite.
3. The solid water treatment composition of claim 1, wherein the
halogen-containing source comprises one or more of a
trichloro-s-triazinetrione, sodium dichloro-s-triazinetrione and
potassium dichloro-s-triazinetrione.
4. The solid water treatment composition of claim 1, wherein the
halogen-containing source comprises trichloro-s-triazinetrione.
5. The solid water treatment composition of claim 1, wherein the
boron-containing source comprises one or more of boric acid or
boric oxide.
6. The solid water treatment composition of claim 1, wherein the
polyphosphate-containing source comprises one or more of sodium
hexametaphosphate, sodium polyphosphate, sodium tripolyphosphate
and sodium pyrophosphate.
7. The solid water treatment composition of claim 1, wherein the
halogen-containing source comprises trichloro-s-triazinetrione, the
boron-containing source comprises boric acid and the
polyphosphate-containing source comprises sodium
hexametaphosphate.
8. The solid water treatment composition of claim 1, wherein the
halogen-containing source is present in the composition in an
amount of about 65 to about 98 weight percent, based on the total
weight of the composition.
9. The solid water treatment composition of claim 1, wherein the
halogen-containing source is present in the composition in an
amount of about 85 to about 95 weight percent, based on the total
weight of the composition.
10. The solid water treatment composition of claim 1, wherein the
boron-containing source is present in the composition in an amount
of about 0.2 to about 2.5 weight percent, based on the total weight
of the composition.
11. The solid water treatment composition of claim 1, wherein the
boron-containing source is present in the composition in an amount
of about 0.5 to about 1.5 weight percent, based on the total weight
of the composition.
12. The solid water treatment composition of claim 1, wherein the
polyphosphate-containing source is present in the composition in an
amount of about 1 to about 10 weight percent, based on the total
weight of the composition.
13. The solid water treatment composition of claim 1, wherein the
polyphosphate-containing source is present in the composition in an
amount of about 4 to about 7 weight percent, based on the total
weight of the composition.
14. The solid water treatment composition of claim 1, in the form
of a tablet, puck or a stick.
15. The solid water treatment composition of claim 1, wherein the
halogen-containing source is present in the composition in an
amount of about 85 to about 95 weight percent, the boron-containing
source is present in the composition in an amount of about 0.2 to
about 2.5 weight percent, and the polyphosphate-containing source
is present in the composition in an amount of about 1 to about 10
weight percent, based on the total weight of the composition.
16-25. (canceled)
26. A solid water treatment composition comprising (a) about 65 to
about 98 weight percent of a N-halogenated compound; (b) a
boron-containing source; and (c) a polyphosphate-containing
source.
27. The solid water treatment composition of claim 26, wherein the
N-halogenated compound comprises one or more of a halogenated
triazinetrione or a halogenated hydantoin.
28. The solid water treatment composition of claim 27, wherein the
N-halogenated compound comprises one or more of a
trichloro-s-triazinetrione, sodium dichloro-s-triazinetrione and
potassium dichloro-s-triazinetrione.
29. The solid water treatment composition of claim 28, wherein the
N-halogenated compound comprises trichloro-s-triazinetrione.
30. The solid water treatment composition of claim 26, wherein the
boron-containing source comprises one or more of boric acid or
boric oxide.
31. The solid water treatment composition of claim 26, wherein the
polyphosphate-containing source comprises one or more of sodium
hexametaphosphate, sodium polyphosphate, sodium tripolyphosphate
and sodium pyrophosphate.
32. The solid water treatment composition of claim 26, wherein the
N-halogenated compound comprises trichloro-s-triazinetrione, the
boron-containing source comprises boric acid and the
polyphosphate-containing source comprises sodium
hexametaphosphate.
33. The solid water treatment composition of claim 26, wherein the
N-halogenated compound is present in the composition in an amount
of about 85 to about 95 weight percent, the boron-containing source
is present in the composition in an amount of about 0.2 to about
2.5 weight percent, and the polyphosphate-containing source is
present in the composition in an amount of about 1 to about 10
weight percent, based on the total weight of the composition.
34. A solid water treatment composition comprising (a) about 65 to
about 98 weight percent of trichloro-s-triazinetrione, (b) a
boron-containing source; and (c) a polyphosphate-containing
source.
35. The solid water treatment composition of claim 34, wherein the
boron-containing source comprises one or more of boric acid or
boric oxide.
36. The solid water treatment composition of claim 34, wherein the
polyphosphate-containing source comprises one or more of sodium
hexametaphosphate, sodium polyphosphate, sodium tripolyphosphate
and sodium pyrophosphate.
37. The solid water treatment composition of claim 34, wherein the
boron-containing source comprises boric acid and the
polyphosphate-containing source comprises sodium
hexametaphosphate.
38. The solid water treatment composition of claim 34, wherein the
trichloro-s-triazinetrione is present in the composition in an
amount of about 85 to about 95 weight percent, the boron-containing
source is present in the composition in an amount of about 0.2 to
about 2.5 weight percent, and the polyphosphate-containing source
is present in the composition in an amount of about 1 to about 10
weight percent, based on the total weight of the composition.
39. A solid water treatment composition comprising from about 65 to
about 98 weight percent trichloro-s-triazinetrione, from about 0.2
to about 2.5 weight percent boric acid, and from about 1 to about
10 weight percent sodium hexametaphosphate, based on the total
weight of the composition.
40. The solid water treatment composition of claim 39, wherein the
trichloro-s-triazinetrione is present in an amount of about 85 to
about 95 weight percent.
41. The solid water treatment composition of claim 39, wherein the
boric acid is present in an amount of about 0.5 to about 1.5 weight
percent.
42. The solid water treatment composition of claim 39, wherein the
sodium hexametaphosphate is present in an amount of about 4 to
about 7 weight percent.
Description
PRIORITY
[0001] This application claims the benefit under 35 U.S.C.
.sctn.119 to U.S. Provisional Application No. 60/856,422, filed on
Nov. 3, 2006, and entitled "SOLID COMPOSITION FOR TREATING WATER",
the contents of which are incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention generally relates to a solid
composition for treating water, e.g., swimming pools, hot tubs,
spas, toilets, etc.
[0004] 2. Description of the Related Art
[0005] In order to insure that the water in, for example, a pool or
spa, is safe, it must be properly sanitized to prevent any health
problems arising due to such contaminants as, for example, algae,
bacteria, or any other pathogens which may be in the water. Thus,
it is the goal of any owner or operator of recreational water
bodies, swimming pools, spas, hot tubs or the like to provide water
which is safe and properly sanitized. To this end, the owner or
operator may choose from a wide variety of biocidal chemical
systems to ensure that a biocidally effective amount of a
water-treating agent is present in the water body on a continuous
basis.
[0006] The more commonly used biocidal agents are
halogen-containing biocides. The halogen is typically chlorine and
can be in a number of different forms, e.g., chlorine gas, alkali
metal hypochlorites, alkaline earth metal hypochlorites,
halogenated hydantoins and chlorinated isocyanuric acid analogues.
Representative examples of such halogen-containing biocides include
sodium hypochlorite (liquid bleach), calcium hypochlorite, lithium
hypochlorite, chlorinated isocyanurates, etc. When any of these
materials interact with water, they undergo hydrolysis to form free
chlorine consisting predominantly of hypochlorous acid (HOCl),
which is the sanitizing agent, and hypochlorite ion.
[0007] Chloroisocyanuric acids (also known as chloroisocyanurates)
are stabilized organic chlorine compounds. Examples of such
chlorine compounds are sodium or potassium
dichloro-s-triazinetrione (commonly known as dichlor) and
trichloro-s-triazintrione (commonly known as trichlor, or TCCA).
Both dichlor and trichlor are used for treating water bodies. When
rapid chlorine delivery is desired, dichlor is commonly used due to
its greater solubility whereas trichlor is commonly used when a
slow and sustained release of chlorine delivery is desired for a
longer period of time due to its lower solubility. Generally,
trichlor is compressed into a tablet form for ease of application
and use which further slows and prolongs the release of chlorine to
the water source.
[0008] It is common practice to blend other performance enhancing
chemicals with the halogen-containing biocides to provide
multifunctionality to the compositions which is highly desirable
for use in water treatment applications. Examples of such
performance enhancing chemicals include algicides, algistats,
flocculants, scale inhibitors, water softeners, dissolution control
aids, chelants, tabletting aids, binders, colorants, and
fragrances.
[0009] It is well known to combine a boron source material such as
boric acid or borax with trichlor along with other additives such
as a non-halogen oxygen donor material or glycoluril. See, e.g.,
U.S. Pat. Nos. 5,478,482; 5,514,287 and 5,670,059. The addition of
a boron source to a chlorine source such as trichlor has typically
been used by the industry for the purpose of providing algistatic
properties in addition to lowering the cost of the composition.
However, one problem associated with this combination is that the
compressed solid composition has a propensity to dissolve at a
faster rate than trichlor itself. See, e.g., U.S. Pat. No.
5,648,314. This rapid dissolution of the chlorine source such as
trichlor is generally undesirable and inconvenient since users are
then required to add the compositions more frequently to maintain
the desired level of residual chlorine in the water. Another
problem associated with this combination is that boron sources are
known to promote the chlorine off-gassing in a trichlor
formulation.
[0010] Trichlor is also known to be formulated with dissolution
aids to increase the speed of dissolution. Examples of such
dissolution aids include salts such as alkali metal and alkaline
earth metal carbonate salts, including sodium carbonate, sodium
bicarbonate, potassium carbonate and calcium carbonate as disclosed
in U.S. Pat. No. 4,389,318. U.S. Pat. No. 6,426,317 teaches the use
of alkali metal salt of 1,3,5-triazine-2,4,6-triones as a
dissolution accelerant for trichlor.
[0011] Another performance enhancing additive that is commonly
added to a trichlor composition is polyphosphates. It is also well
known that the addition of a polyphosphate softens the water and
helps minimize the scale build up on pipes and heat exchangers.
See, e.g., U.S. Pat. No. 3,488,420.
[0012] However, there are drawbacks to using many of these
additives. Most of these functional additives are highly water
soluble and tend to make such trichlor compressed solid
compositions dissolve faster than that made from trichlor alone.
Trichlor products also give off chlorine gas and in combination
with some of these additives also impart chemical instability in
the final formulation which is of concern for sale on a commercial
level.
[0013] A need therefore exists for improved solid water treatment
compositions containing a halogen-containing source such as a
chlorine source for treatment of water without affecting
dissolution while reducing halogen off-gassing, e.g., chlorine
off-gassing.
SUMMARY OF THE INVENTION
[0014] In accordance with one embodiment of the present invention,
a solid water treatment composition is provided comprising (a) a
halogen-containing source; (b) a boron-containing source; and (c) a
polyphosphate-containing source.
[0015] In accordance with a second embodiment of the present
invention, a process for preparing a solid water treatment
composition is provided comprising (a) dry blending (i) a
halogen-containing source; (ii) a boron-containing source; and
(iii) a polyphosphate-containing source; (b) granulating the blend
into granules; and (c) tableting the granules.
[0016] In accordance with a third embodiment of the present
invention, a process for preparing a solid water treatment
composition is provided comprising (a) dry blending (i) a
halogen-containing source; and (ii) a polyphosphate-containing
source; (b) granulating the blend into granules; (c) blending the
granules with a boron-containing source; and (d) tableting the
blended granules.
[0017] In accordance with a fourth embodiment of the present
invention, a method for controlling microbial growth in a water
system is provided comprising adding to the water system a solid
water treatment composition comprising (a) a halogen-containing
source; (b) a boron-containing source; and (c) a
polyphosphate-containing source.
[0018] In accordance with a fifth embodiment of the present
invention, a method for reducing the halogen off-gassing rate in a
solid water treatment halogen-containing composition is provided
comprising forming a solid water treatment halogen-containing
composition comprising (a) a halogen-containing source; (b) a
boron-containing source and (c) a polyphosphate-containing
source.
[0019] The solid water treatment compositions of the present
invention containing a halogen-containing source, a
boron-containing source and a polyphosphate-containing source
advantageously possess a dissolution rate relatively similar to
solid water treatment compositions containing a halogen-containing
source alone. Additionally, the solid water treatment compositions
of the present invention significantly reduce the halogen
off-gassing, e.g., chlorine off-gassing, during use. In this
manner, a longer lifespan of the solid water treatment compositions
during use can be achieved while also reducing halogen off-gassing.
This is particularly advantageous as chlorine off-gassing can lead
to label fading, bleaching of bottles, pails and lids, and the
degradation of cardboard. Furthermore, the odor associated with
halogen off-gassing is unpleasant to the end-use consumer and
absorbent sachets are typically co-packed with the end-use product
to help mitigate this effect at an additional cost of material and
labor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a bar graph showing the dissolution rates of a
trichlor tablet, trichlor and sodium hexametaphosphate (SHMP)
tablet and a tablet according to an embodiment of the present
invention.
[0021] FIG. 2 is a bar graph showing the dissolution rates of boric
acid on a trichlor tablet.
[0022] FIG. 3 is a bar graph showing the dissolution rates of boron
compounds on a trichlor tablet.
[0023] FIG. 4 is a bar graph showing the off-gassing rate of a
trichlor tablet and a tablet according to an embodiment of the
present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] The present invention provides solid water treatment
compositions and methods for the treatment of a variety of water
systems. For example, the solid water treatment compositions and
methods of the present invention are useful for the treatment of
such as water systems as cooling towers, evaporative condensers,
swimming pools, hot tubs, spas and toilets. The solid compositions
are readily adapted for use in these and other environments. In one
embodiment, a solid water treatment composition contains at least
(a) a halogen-containing source; (b) a boron-containing source; and
(c) a polyphosphate-containing source. The solid water treatment
compositions can be in any suitable solid form, e.g., tablet,
powder, or a stick
[0025] The halogen-containing source is any compatible halogen
material useful in solid form. Suitable halogens include chlorine
or bromine, and may be any solid-form material which provides the
halogen in the form of hypohalite ions, i.e., hypochlorite or
hypobromite ions, or as hypohalous acid. For example, the halogen
containing source may include various chlorine compounds including
chlorinated hydantoins, calcium hypochlorite, lithium hypochlorite,
sodium dichloro-s-triazinetrione, potassium
dichloro-s-triazinetrione, trichloro-s-triazinetrione and the like
and mixtures thereof. Suitable bromine compounds include brominated
hydantoins. Representative examples of halogenated hydantoins
include 1-bromo-3-chloro-5,5-dimethylhydantoin (BCDMH),
1,3-dichloro-5,5-dimethylhydantion (DCDMH),
1,3-dichloro-5-ethyl-5-methylhydantoin,
1,3-dibromo-5,5-dimethylhydantion (DBDMH) and the like and mixtures
thereof.
[0026] In one embodiment, the halogen-containing source is dichlor,
trichlor and mixtures thereof. In another embodiment, the
halogen-containing source is trichlor. In one embodiment, the
halogen-containing source is a N-halogenated compound such as
halogenated triazinetrione and halogenated hydantoin as discussed
above and the like and mixtures thereof.
[0027] The boron-containing source is any suitable boron compound
or mixture thereof. For example, the boron-containing source can be
boric acid, boric oxide (anhydrous boric acid), compounds having
the formula MnB.sub.xO.sub.y.ZH.sub.2.alpha., wherein M is any
alkali earth or metal/non-metallic cation, e.g., sodium, potassium,
calcium, magnesium and ammonium, n is 1 to 3, x is any whole number
from 2 to 10, y is (3x/2)+1, and z is 1 to 14, and the like and
mixtures thereof. Representative examples of compounds having the
formula MnB.sub.xO.sub.y.ZH.sub.2O include disodium tetraborate
decahydrate, disodium tetraborate pentahydrate, disodium
tetraborate tetrahydrate, disodium octaborate tetrahydrate, sodium
pentaborate pentahydrate, sodium metaborate tetrahydrate, sodium
metaborate bihydrate, dipotassium tetraborate tetrahydrate,
potassium pentaborate tetrahydrate, diammonium tetraborate
tetrahydrate, ammonium pentaborate tetrahydrate and the like and
mixtures thereof.
[0028] The polyphosphate-containing source is any suitable
polyphosphate compound or mixture thereof. Representative examples
of polyphosphates include alkali metal polyphosphates such as
sodium hexametaphosphate. In one embodiment, the
polyphosphate-containing source is one or more of sodium
hexametaphosphate, sodium polyphosphate, sodium tripolyphosphate or
sodium pyrophosphate.
[0029] In general, the solid water treatment compositions of the
present invention will contain from about 65 to about 98 weight
percent and preferably from about 85 to about 95 weight percent of
the halogen-containing source, from about 0.2 to about 2.5 weight
percent and preferably from about 0.5 to about 1.5 weight percent
of the boron-containing source and from about 1 to about 10 weight
percent and preferably from about 4 to about 7 weight percent of
the polyphosphate-containing source, based on the total weight of
the composition.
[0030] The solid water treatment compositions of the present
invention can also contain one or more conventional additives as
known in the art. Suitable additives and the amounts to use may be
readily determined by one skilled in the art. Examples of such
additives include, but are not limited to, a clarifier, algaecide,
algistat, tableting aids, coloring agents, dyes, fragrances and the
like and mixtures thereof.
[0031] The solid water treatment compositions can be formed into
any suitable solid form, e.g., tablets, pack or a stick. Tablets
containing the compositions according to the present invention may
be produced by any standard tabletting technique, e.g. by wet
granulation, dry granulation or direct compression. Blending and
granulating of the tablet constituents during the preparation of a
tablet composition may be accomplished by any method which causes
the composition to become blended. Once the tablet compositions are
prepared, they may be formed into various shapes. In a preferred
embodiment, the tablet compositions are pressed into a shape. This
process may involve placing the tablet composition into a form and
applying pressure so as to cause the composition to assume the
shape of the surface of the form with which the composition is in
contact. Examples of presses which can be used to compress the
tablet compositions of the present invention include hydraulic
presses such as a Carver Press and the like or mechanical presses
such as a Baldwin press and the like.
[0032] In one embodiment, the solid water treatment compositions of
the present invention is prepared by (a) dry blending (i) a
halogen-containing source; (ii) a boron-containing source and (iii)
a polyphosphate-containing source; (b) granulating the blend into
granules; and (c) tableting the granules.
[0033] In another embodiment, the solid water treatment
compositions of the present invention is prepared by (a) dry
blending (i) a halogen-containing source; and (ii) a
polyphosphate-containing source; (b) granulating the blend into
granules; (c) blending the granules with a boron-containing source;
and (d) tableting the blended granules.
[0034] In the water treatment method of this invention the one or
more solid water compositions as described above are inserted into
the water body to be treated whereby the tablet dissolves over
time.
[0035] The following examples are provided to enable one skilled in
the art to practice the invention and are merely illustrative of
the invention. The examples should not be read as limiting the
scope of the invention as defined in the features and
advantages.
[0036] The general procedure for all examples was as follows.
Tablets weighing about 6 ounces (oz.) and 8 oz. were manufactured
on either a laboratory or commercial press, e.g., a hydraulic press
such as a carver press or a mechanical press such as a Baldwin
press. The compression time and pressure were controlled to yield
tablets that had crush strengths similar to commercial trichlor
products with similar dimensions and mass. All tablets were made
having a 3'' diameter.
Comparative Example A
[0037] Trichlor tablets were prepared by compressing trichlor in
granular form into 8 oz. tablets on a commercial press.
[0038] Dissolution tests were then carried out to determine the
dissolution rate of the control tablet of this example. The test
results are set forth below in Table 1 and in FIG. 1. The
dissolution test was carried out as follows.
[0039] Dissolution
[0040] Tablet dissolution rates were monitored in a 5,000 gallon
(19,000 L) pool equipped with two skimmers that are typically used
in swimming pools. Flow rates through the skimmers were maintained
at 20 gallons/minute (76 L/min), unless otherwise noted. The pump
run time was 10 hours/day to maintain water flow through the
skimmers. The pool temperature was maintained at 85.degree. F. (or
26.7.degree. C.). In one study, the skimmer basket was charged with
one tablet each of Comparative Example A, Example 1 and Comparative
Example B. In another study, the skimmer basket was charged with
one tablet each of Comparative Examples C-E. In another study, the
skimmer basket was charged with one tablet each of Comparative
Example F-H.
[0041] The initial tablet weight was determined before placing the
tablet in the skimmer. The skimmer basket was removed every 24
hours from the skimmer and the tablet was gently patted dry and
weighed. Also, the skimmer basket was periodically rotated every 24
hours by 180 degrees to expose the tablets to the similar water
flow conditions in the skimmer. Throughout the course of the study,
the pool water was maintained at a pH of 7.2 to 7.8, total
alkalinity of 100 to 175 ppm, and calcium hardness of 175 to 300
ppm.
TABLE-US-00001 TABLE I Dissolution of Trichlor (8 oz. Tablet)
Tablet Weight, g 0 hr 24 hrs 48 hrs 72 hrs 96 hrs Study 1 230.00
162.46 94.29 33.66 9.19 Study 2 235.56 174.69 107.72 50.23 4.80
Study 3 234.69 148.66 79.62 34.20 9.66 Avg. 233.42 161.94 93.88
39.36 7.88
Example 1
[0042] A compressed tablet was prepared from trichlor (94 wt. %),
sodium hexametaphosphate (SHMP) (6 wt. %), boric acid (BA) (0.75
wt. %) and pigment (Orcolite Blue) (0.2 wt. %). First, trichlor and
SHMP were blended together and then compressed and comminuted to
provide co-compacted granules. The co-compacted granules were
blended with BA and pigment in a V-blender and then subsequently
compressed into 8 oz. tablets on a commercial press. Note that the
total amount of ingredients in this composition exceeded 100% on
weight basis.
[0043] The tablets were then subjected to the dissolution test
discussed above. The test results are set forth below in Table II
and FIG. 1.
TABLE-US-00002 TABLE II Dissolution of Trichlor with SHMP and BA (8
oz. Tablet) Tablet Weight, g 0 hr 24 hrs 48 hrs 72 hrs 96 hrs Study
1 219.33 147.92 92.51 47.83 26.29 Study 2 222.24 162.38 98.03 56.53
24.99 Study 3 227.35 132.18 74.74 42.75 23.12 Avg. 222.97 147.49
88.43 49.04 24.80
[0044] As the dissolution data show, the tablet of the present
invention has a dissolution rate similar to the trichlor tablet of
Comparative Example A.
[0045] The test results of Table II are unexpected and contrary to
what has been reported thus far in the prior art that trichlor
compositions with a variety of water soluble additives increase the
dissolution rate of trichlor tablets. The tablet of Example 1
containing trichlor, sodium hexametaphosphate and boric acid
possessed similar dissolution characteristics to the tablet of
Comparative Example A containing trichlor alone.
Comparative Example B
[0046] A solid compressed tablet was prepared with trichlor (94 wt.
%) and SHMP (6 wt. %). Using the general procedure described above,
the tablet ingredients were blended, compressed and comminuted to
provide co-compacted granules that are tableted into 8 oz. tablets
on a laboratory press. The blend was compressed into 8 oz. tablets
on a commercial press.
[0047] The dissolution rate of these tablets was determined as
described above. The test results are set forth below in Table III
and FIG. 1.
TABLE-US-00003 TABLE III Dissolution of Trichlor with SHMP (8 oz.
Tablet) Tablet Weight, g 0 hr 24 hrs 48 hrs 72 hrs 96 hrs Study 1
228.42 143.39 80.56 23.28 1.78 Study 2 232.1 158.33 94.01 28.18
0.00 Study 3 227.1 138.37 64.93 21.21 1.52 Avg. 229.18 146.70 79.83
24.22 1.10
[0048] As the dissolution data show, the tablet of Comparative
Example B containing trichlor and SHMP has a faster dissolution
rate than the tablet of Comparative Example A containing trichlor
alone. This finding is in contrast to the results reported in U.S.
Pat. No. 3,488,420 which shows the addition of sodium
hexametaphosphate to trichlor results in a tablet with a much
slower rate of dissolution.
[0049] Also, a comparison of the tablet of Comparative Example B
with the tablet of Example 1 showed that addition of boric acid to
the granular composition of trichlor and sodium hexametaphosphate
tablet decreased the rate of dissolution of the tablet (FIG.
1).
Comparative Examples C-E
[0050] This example shows the effect of boric acid on the
dissolution of a tablet containing trichlor. For these experiments,
three 6 oz. tablets of the following compositions were made in the
laboratory.
Comparative Example C
[0051] Trichlor tablet: Trichlor alone (100 wt. %) in granular form
was compressed into a tablet on a laboratory press.
Comparative Example D
[0052] Trichlor (95 wt. %)+BA (5 wt. %) tablet: The materials were
blended and compressed into a tablet on a laboratory press.
Comparative Example E
[0053] Trichlor (95 wt. %)+BA (5 wt. %) tablet: The materials were
blended, compressed and comminuted to provide co-compacted
granules. The co-compacted granules were subsequently compressed
into a tablet on a laboratory press.
[0054] The dissolution rate of these tablets was determined as
described above except the flow rate was 32 gpm. The test results
for Comparative Examples C-E are set forth below in Table IV and
FIG. 2.
TABLE-US-00004 TABLE IV Effect of Boric Acid on Trichlor
Dissolution (6 oz. Tablet) Tablet Weight, g Comp. Ex. 0 hr 24 hrs
48 hrs 72 hrs Comp. Ex. C 170.56 137.97 50.50 1.70 Comp. Ex. D
170.47 117.08 15.30 0.00 Comp. Ex. E 170.67 117.43 14.85 0.00
[0055] As the dissolution data show, the tablets of Comparative
Examples D and E containing trichlor and boric acid exhibited a
significant increase in the dissolution rate compared to the tablet
of Comparative C containing trichlor alone. The data further showed
that there is no effect on tablet dissolution when either a
blending processing method or co-compaction processing method is
used in preparing the tablets of Comparative Examples D and E.
Comparative Examples F-H
[0056] This example compares the effect of different boron
compounds on the dissolution of a tablet containing trichlor. For
these experiments, three 8 oz. tablets of the following
compositions were made in the laboratory:
Comparative Example F
[0057] Trichlor (100 wt. %) tablet: Trichlor in granular form was
compressed into tablet on a laboratory press.
Comparative Example G
[0058] Trichlor (95 wt. %)+BA (5 wt. %) tablet: The materials were
blended and compressed into a tablet on a laboratory press.
Comparative Example H
[0059] Trichlor (95 wt. %)+borax (5 wt. %) tablet: The materials
were blended, compressed and comminuted to provide co-compacted
granules. The co-compacted granules were subsequently compressed
into a tablet on a laboratory press.
[0060] The dissolution rate of these tablets was determined as
described above except the pump flow rate was 33 gpm. The test
results for Comparative Examples F-H are set forth below in Table V
and FIG. 3.
TABLE-US-00005 TABLE V Effect of Boron Compounds on Trichlor
Dissolution (8 oz. Tablet) Tablet Weight, g Comp. Ex. 0 hr 24 hrs
48 hrs Comp. Ex. F 227.79 174.53 124.37 Comp. Ex. G 227.31 147.45
86.79 Comp. Ex. H 228.01 137.39 71.61
[0061] As the dissolution data show, the addition of a boron
compound to trichlor increased the dissolution of the tablet
(Comparative Examples G and H) as compared to the tablet containing
trichlor alone (Comparative Example F).
Comparative Example I
[0062] Trichlor tablets (8 oz.) were prepared in substantially the
same manner as in Comparative Example A.
Example 2
[0063] A solid compressed tablet was prepared from trichlor (95 wt.
%), SHMP (4 wt. %) and BA (1 wt. %). First, trichlor and SHMP were
blended together and then compressed and comminuted to provide
co-compacted granules. The co-compacted granules were blended with
BA in a V-blender and then subsequently compressed into 8 oz.
tablets on a commercial press.
Example 3
[0064] This example illustrates that the solid water compositions
of the present invention reduce off-gassing. Chlorine off-gassing
was determined for 37 commercial production lots of the tablets of
Comparative Example 1 and 12 tablets of Example 2. The chlorine
off-gassing of the tablets of Comparative Example I and the tablets
of Example 2 were predicted by heating a 20 g sample in a sealed
ampoule at 60.degree. C..+-.2.degree. C. for 2 hours and
determining the chlorine content in the sample headspace by gas
chromatography. The results are set forth below in Table VI and
FIG. 4.
TABLE-US-00006 TABLE VI Comp. Ex./Ex. Chlorine off-gassing, % Std.
Dev. Comp. Ex. I 1.1047 0.2224 Example 2 0.5730 0.1502
[0065] As the data show, a significant decrease in chlorine
off-gassing can be obtained by using the tablet of Example 2
(within the scope of the present invention) as compared to the
tablet of Comparative Example I (outside the scope of the present
invention), i.e., 0.57% versus 1.10%. The difference in the
chlorine off-gassing is a decrease of 48% which is an order of
magnitude greater than would be expected from the relatively small
decrease in trichlor concentration by the addition of SHMP (4 wt.
%) and BA (1%).
[0066] While the invention has been illustrated and described in
detail in the foregoing description, the same is to be considered
illustrative and not restrictive in character, it being understood
that only the preferred embodiment has been shown and described and
that all changes and modifications that come within the spirit of
the invention are desired to be protected.
* * * * *