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| United States Patent |
4,380,501 |
| Wojtowicz , et al. |
April 19, 1983 |
Gas scavenger agents for containers of solid chloroisocyanurates
Abstract
Chlorine-containing gases which may be formed in containers of solid
chloroisocyanurates such as trichloroisocyanuric are adsorbed and decomposed by
a gas scavenging agent consisting essentially of an alkaline earth metal
sulfate, an alkali metal bicarbonate, and carbon. The gas scavenging agent is
preferably contained in a gas permeable package which is enclosed in the
container. The scavenging agent adsorbs mositure, adsorbs and decomposes
nitrogen trichloride, removes chlorine, and neutralizes hydrogen chloride gases
formed. Harmful build-up of noxious gases and the reduction of gas pressures
within containers for solid chloroisocyanurates is achieved.
| Inventors: |
Wojtowicz; John A. (Cheshire, CT);
Gergo; Andree M. B. (East Haven, CT) |
| Assignee: |
Olin Corporation (New Haven, CT) |
| Appl. No.: |
262574 |
| Filed: |
May 11, 1981 |
| Current U.S. Class: |
252/186.24; 8/109;
252/181.4; 252/181.5; 252/186.35 |
| Intern'l Class: |
C11D 003/48; C11D 003/24; C11D
003/395 |
| Field of Search: |
252/90,95,181.4,181.5,187 C 423/210
8/109 |
References Cited [Referenced
By]
U.S. Patent Documents
| 3061549 |
Oct., 1962 |
Dickey |
252/90. |
| 3183057 |
May., 1965 |
Marks et al. |
21/58. |
| 3431206 |
Mar., 1969 |
Hilton et al. |
252/187. |
| 3454699 |
Jul., 1969 |
Symes |
252/187. |
| 4149988 |
Apr., 1979 |
Brennan et al. |
252/187. |
Primary
Examiner: Kight, III; John
Assistant Examiner: Nutter; Nathan M.
Attorney, Agent or Firm: Haglind; James B., Clements; Donald F.
Claims
What is claimed is:
1. In a container of a solid
chloroisocyanurate composition, the improvement which comprises enclosing
therein a gas scavenging agent consisting essentially of a mixture of an
alkaline earth metal sulfate, an alkali metal bicarbonate, and carbon.
2. The container of claim 1 in which said solid chloroisocyanurate is
selected from the group consisting of trichloroisocyanuric acid,
dichloroisocyanuric acid, alkali metal salts of dichloroisocyanuric acid,
alkaline earth metal salts of dichloroisocyanuric acid, and mixtures thereof.
3. The container of claim 2 in which said gas scavenging composition is
contained in a sealed, gas permeable package.
4. The container of claim
3 in which said mixture comprises at least 5 percent by weight of each of said
alkaline earth metal sulfate, said alkali metal bicarbonate, and said carbon.
5. The container of claim 4 in which said alkali metal bicarbonate is
anhydrous sodium bicarbonate.
6. The container of claim 5 in which said
alkaline earth metal sulfate is selected from the group consisting of calcium
sulfate and magnesium sulfate and lower hydrates thereof.
7. The
container of claim 6 in which said carbon is activated carbon.
8. The
container of claim 7 in which said solid chloroisocyanurate is
trichloroisocyanuric acid.
9. The container of claim 8 in which the
amount of said gas scavenging agent is from about 0.5 to about 10 percent by
weight of said solid chloroisocyanurate.
10. The container of claim 9 in
which compressed form of said solid chloroisocyanurate is selected from the
group consisting of tablets, rings, briquets, and sticks.
11. The
container of claim 10 in which said alkaline earth metal sulfate is magnesium
sulfate.
12. The container of claim 11 in which said mixture comprises
at least 10 percent by weight of each of said alkaline earth metal sulfate, said
alkali metal bicarbonate, and said carbon.
13. The container of claim 2
in which said carbon is coated with a metal salt selected from the group
consisting of copper salts, cobalt salts, nickel salts, chromium salts, and
mixtures thereof.
14. A gas scavenging agent for scavenging gases
containing nitrogen trichloride which consists essentially of a gas permeable
package enclosing a mixture of an alkaline earth metal sulfate, an alkali metal
bicarbonate, and carbon.
Description
This invention relates to improved packaging for chloroisocyanurate
compositions used as dry sanitizing and disinfecting agents.
Chloroisocyanurates such as trichloroisocyanuric acid have a degree of
instability which, for example, in the presence of moisture or heat results in
their decomposition. This decomposition includes the evolution of highly noxious
and otherwise objectionable gases such as nitrogen trichloride, chlorine, and
mixtures thereof. U.S. Pat. No. 3,183,057 issued to H. C. Marks, R. R. Joiner
and G. U. Glasgow teaches the generation of these gases from dry solid N-chloro
compounds by their reaction with acidic and alkaline reagents in the presence of
moisture. The reagents are enclosed in a moisture permeable envelope which
allows sufficient moisture to initiate and sustain the reaction to evolve the
gases. Water soluble acids and alkaline reagents are employed as reactants
together with dichloroisocyanuric acid or trichloroisocyanuric acid. The
envelope may contain as simple carriers or diluents inert substances such as
calcium sulfate or magnesium sulfate.
It is frequently desirable,
however, to produce packages for chloroisocyanurates in which the evolution of
the pungent, nauseating chlorine-containing gases is inhibited by, for example,
a deodorizing agent.
U.S. Pat. No. 2,897,154 issued to R. L. Low teaches
the use of silver compounds such as silver nitrate, silver phosphate, silver
oxide, or silver carbonates, as well as mercuric nitrate. These salts are
expensive to employ, and in addition, the use of mercuric nitrate may impose a
pollution problem.
Materials such as mixtures of manganese dioxide and
cupric oxide, activated alumina, activated carbon, zeolites, bentonite, alkali
metal silicates, alkali metal hydroxides, potassium, rubidium or cesium
carbonates, or alkaline earth oxides are described as suitable deodorants in
U.S. Pat. No. 3,061,549 issued to M. L. Dickey.
U.S. Pat. No. 4,146,578
issued Mar. 27, 1979, to J. P. Brennan, J. M. Casberg, and C. H. Putnam teaches
decomposition inhibitors for solid chloroisocyanurates containing an alkaline
earth metal sulfate or mixtures of an alkaline earth metal sulfate with an
alkali metal bicarbonate or an alkali metal sulfite.
Further research
into the mechanisms of the decomposition of solid chloroisocyanurates has shown
that in addition to absorbing vapors formed during any decomposition of the
solid chloroisocyanurates, it is desirable to convert these noxious gaseous
decomposition products into innocuous gases.
Therefore there is need for
an improved composition to inhibit and neutralize gases formed within containers
of solid chloroisocyanurates.
It is an object of the present invention
to provide a gas scavenger agent which is effective in preventing the
accumulation of noxious gases in packages containing solid chloroisocyanurates.
An additional object of the present invention is to provide a gas
scavenger agent which adsorbs and decomposes noxious gases such as nitrogen
trichloride formed in packages containing solid chloroisocyanurates.
A
further object of the present invention is to provide a scavenger agent which
rapidly neutralizes acidic gases formed during decomposition of solid
chloroisocyanurates.
These and other objects of the present invention
are accomplished in a container of a solid chloroisocyanurate composition, the
improvement which comprises enclosing therein a gas scavenging agent consisting
essentially of an alkaline earth metal sulfate, an alkali metal bicarbonate, and
carbon.
More in detail, solid chloroisocyanurate compositions include
those containing trichloroisocyanuric acid, dichloroisocyanuric acid, salts of
dichloroisocyanuric acid such as alkali metal dichloroisocyanurates and alkaline
earth metal dichloroisocyanurates as well as complexes and mixtures thereof.
Preferred solid chloroisocyanurate compositions are trichloroisocyanuric acid
and alkali metal dichloroisocyanurates, with trichloroisocyanuric acid being
particularly preferred. The solid chloroisocyanurates can be in any suitable
form including granular or compressed forms such as tablets, rings, briquets,
sticks, etc.
Solid chloroisocyanurate compositions are shipped and sold
in a variety of containers including drums, bottles, cans, boxes, etc. The
containers are closed, but are not completely sealed to allow escape of gases
formed by any decomposition which might take place and prevent a buildup of gas
pressure within the container.
Dry solid chloroisocyanurates are
sensitive to moisture and heat and in their presence decomposition may take
place resulting in the formation of noxious gases including chlorine, nitrogen
trichloride, and often hydrogen chloride. While the exact mechanism of noxious
gas formation within the containers of solid chloroisocyanurates is unknown, and
not wishing to be bound by theory, it is believed that moisture present in the
product or entering the container hydrolyzes the chloroisocyanurate to initially
form hypochlorous acid. Hypochlorous acid reacts with additional
chloroisocyanurate to produce nitrogen trichloride. Subsequent decomposition of
nitrogen trichloride forms chlorine. Carbon dioxide gas is also formed during
the decomposition of solid chloroisocyanurates. While not reactive with the
compounds, its presence increases the gas pressure within the container.
Hydrogen chloride is believed to be formed by the reaction of chlorine present
with certain packaging materials, for example, polyolefins.
The novel
gas scavenging composition of the present invention interacts with these
decomposition products to decompose nitrogen trichloride to chlorine and
nitrogen gases, absorb the chlorine formed, and neutralize any hydrogen chloride
which is formed.
The gas scavenging composition of the present invention
consists essentially of a mixture of an alkaline earth metal sulfate, an alkali
metal bicarbonate, and carbon. Each of these ingredients is employed in a
particulate form of the solid.
Suitable alkaline earth metal sulfates
used in the gas scavenging compositions include calcium sulfate or magnesium
sulfate. Magnesium sulfate is a preferred embodiment because of its superior
moisture absorbing properties. Where the gas scavenging composition is contained
in a gas permeable package, the particle size of the alkaline earth metal
sulfate is selected to be sufficiently large to prevent leakage through or
plugging of the pores of the package material. When the composition is
distributed loosely throughout the container of the solid chloroisocyanurate,
suitable particle sizes are those, for example, in the range of from about 40 to
about 4000, and preferably from about 70 to about 2000 microns. The anhydrous
form of the alkaline earth metal sulfate is preferred, however, lower hydrates
such as magnesium sulfate monohydrate may be used to provide coarser particles.
Alkali metal bicarbonates which can be employed in the gas scavenging
compositions include sodium bicarbonate or potassium bicarbonate, with sodium
bicarbonate being a preferred embodiment. Alkali metal bicarbonates remove and
inactivate chlorine and hydrogen chloride gases. Suitable particle sizes for the
anhydrous bicarbonate particles include those in the range of from about 40 to
about 300 and preferably from about 80 to about 200 microns.
The third
ingredient of the gas scavenging composition, carbon, is employed as
substantially anhydrous porous particles which may be either unactivated or
activated, with activated carbon particles being preferred. Carbon granules
employed are those having substantial amounts of internal and external surface
area which adsorb chlorine and carbon dioxide and promote the decomposition of
nitrogen trichloride. The granules may have any suitable particle sizes, for
example, those in the range of from about 100 to about 2000 microns, and
preferably from about 200 to about 1700 microns.
The carbon particles
may be coated or impregnated with metal salts such as those of copper, nickel,
cobalt, and chromium including, for example, the chlorides, sulfates, nitrates,
oxides, or hydroxides of these metals. Preferred as coatings or impregnants are
metal salts of cobalt, nickel, or copper which are more soluble in water such as
cobalt chlorides, cobalt sulfates, cobalt nitrates, nickel chlorides, nickel
sulfates, nickel nitrates, copper chlorides, copper sulfates, copper nitrates,
and mixtures thereof with cobalt chlorides, nickel chlorides, copper chlorides,
and mixtures thereof being particularly preferred.
The gas scavenging
compositions of the present invention may include a wide range of component
ratios to effectively remove and inactivate noxious chlorine-containing gases.
Suitably the gas scavenging compositions contain at least 5 percent by weight of
each of the components. Preferably, the alkaline earth metal sulfate, the alkali
metal bicarbonate, and carbon are each present in at least 10 percent by weight.
More preferably, the gas scavenging composition of the present invention
contains at least 20 percent by weight of each of the three components. For
example, where the solid chloroisocyanurate is trichloroisocyanuric acid, the
gas scavenging composition may contain preferably at least 10 percent by weight
of carbon and the alkaline earth metal sulfate and the alkali metal bicarbonate
each in amounts in the range of from about 10 to about 80 percent by weight.
When the solid chloroisocyanurate is an alkali metal salt of dichloroisocyanuric
acid such as sodium dichloroisocyanurate dihydrate, the portion of alkaline
earth metal sulfate can be reduced and preferred component weight ratios include
those in which the alkaline earth metal sulfate is at least 10 percent by weight
and the alkali metal bicarbonate and carbon are each present in amounts in the
range of from about 10 to about 80 percent by weight. The cumulative total
being, of course, no greater than 100 percent.
The novel gas scavenging
compositions of the present invention may be admixed directly with the solid
chloroisocyanurate, for example, by introducing the compositions into the
container. Where this method is used the solid chloroisocyanurate is preferably
in a compressed form such as that of a tablet, stick, or briquet.
In a
preferred embodiment, the gas scavenging composition is enclosed in a gas
permeable package which is deposited in the container of solid
chloroisocyanurate. The package is suitably made of any chlorine-resistant
material and whose permeability permits the admission of Cl.sub.2, NCl.sub.3,
CO.sub.2, and N.sub.2 gases and moisture vapor while preventing leakage of the
particulate components of the scavenging composition. Suitable materials
include, for example, polyolefins such as polyethylene and polypropylene,
polyesters, and polyvinyl chloride in film or fabric form.
Considerable
savings on materials result where the gas scavenging compositions are enclosed
in a package as only about 50 percent as much is required as where the gas
scavenging composition is directly admixed with the solid chloroisocyanurate.
Any amounts of the gas scavenging compositions may be employed which
will effectively remove moisture and render innocuous noxious gases which may be
formed. For example, commercially produced trichloroisocyanuric acid has a
moisture content of about 0.2 percent and preferably less than 0.1 percent by
weight of water. Suitable amounts of the gas scavenging compositions admixed
with commercial trichloroisocyanuric acid include those in the range of from
about 0.5 to about 10, preferably from about 0.8 to about 6, and more preferably
from about 1 to about 4 percent by weight of said trichloroisocyanuric acid.
Packages of the gas scavenging compositions of the present invention may
also be used in containers of products including solid chloroisocyanurates as a
component. For example, containers of detergent mixtures, sanitizing
compositions, cleansing agents, and bleaching compositions in which solid
chloroisocyanurates are used as a source of available chlorine are protected
from damage and the release of noxious chlorine-containing gases by the
inclusion of a package of the novel gas scavenging compositions of the present
invention.
Suitable packages of these compositions may also be used in
air filtering or purifying equipment which is employed in areas in which
chlorine-containing gases such as nitrogen trichloride are produced.
The
novel gas scavenging compositions of the present invention when enclosed in
containers of solid chloroisocyanurates effectively inhibit the accumulation or
release of moisture in the container. Chlorine-containing gases such as chlorine
are adsorbed while nitrogen trichloride is both adsorbed and decomposed.
Further, the gas scavenging compositions neutralize acidic gases such as
hydrogen chloride which may be formed. Containers for solid chloroisocyanurates
enclosing the gas scavenging compositions can be sealed more tightly as the
accumulation of gases in the container and hence the internal gas pressure is
significantly reduced. A tighter seal reduces the amount of moisture vapor and
atmospheric gases which can enter the container. If the container's seal is
defective, the gas scavenging compositions will prevent excessive decomposition
of the solid chloroisocyanurates contained within.
Employing the novel
gas scavenging composition prevents embrittlement of the container itself as
well as inhibiting bleaching of container components such as caps and labels.
The novel gas scavenging compositions of the present invention are
further illustrated by the following examples without any intention of being
limited thereby. All percentages are by weight unless otherwise specified.
EXAMPLE 1
A mixture was prepared of commercial grade anhydrous
magnesium sulfate, commercial grade anhydrous sodium bicarbonate, and activated
carbon particles having a particle size in the range of 14 to 40 mesh. The
carbon particles had been immersed in an aqueous solution of a mixture of
CuCl.sub.2, NiCl.sub.2, and CoCl.sub.2 and dried. The dried carbon particles
contained 0.4 percent each of CuCl.sub.2, NiCl.sub.2, and CoCl.sub.2. The
mixture (28 grams) containing 18 percent by weight of magnesium sulfate, 64
percent by weight of sodium carbonate, and 18 percent by weight of carbon
particles was added to a small glass beaker. The beaker was placed in an upright
position near the top of a plastic container holding 1816 grams of
trichloroisocyanuric acid tablets. The plastic container was sealed with a
bright orange screw cap having a polyethylene foam liner. The plastic container
enclosing the beaker of gas scavenger agent was placed in a room whose
atmosphere was controlled at a temperature of 110.degree. F. and 55 percent
relative humidity. Samples of gas decomposition products were taken periodically
by piercing the upper part of the container with a hypodermic needle,
withdrawing a 1 cc sample of gas, and resealing the opening. The gas sample was
analyzed by gas chromatography for nitrogen trichloride and chlorine. A visual
inspection was also made of the orange bottle cap to ascertain evidence of
bleaching. Bleaching of the top of the orange cap was found to have occurred
after a period of 235 days. Analytical results are given in TABLE I below.
COMPARATIVE EXAMPLES A-E
The procedure of EXAMPLE 1 was repeated
using as scavenging agents 28 grams of each of the following: anhydrous sodium
bicarbonate; anhydrous magnesium sulfate; a mixture of sodium bicarbonate and
magnesium sulfate in equal amounts; activated carbon containing 0.4 percent each
of CuCl.sub.2, NiCl.sub.2, and CoCl.sub.2 ; and anhydrous activated carbon. The
carbon particles had a particle size in the range of 14 to 40 mesh. A glass
beaker of each of these scavenging agents was placed inside a plastic container
identical to that of EXAMPLE 1 holding 1816 grams of trichloroisocyanuric acid
tablets and sealed with an orange plastic top having a poly foam liner. A
plastic container of trichloroisocyanuric acid tablets having no scavenging
agent was used as the control. Each of these plastic containers was placed in
the controlled atmosphere room in which the identical conditions of temperature
(110.degree. F.) and humidity (55% RH) employed in EXAMPLE 1 were maintained.
Gases formed by decomposition of the trichloroisocyanuric acid tablets were
analyzed periodically by the method of EXAMPLE 1. A visual observation was also
made of the bleaching of the orange cap. The results for COMPARATIVE EXAMPLES
A-E are reproduced in TABLE 1 below.
TABLE I
__________________________________________________________________________
GAS SCAVENGERS FOR CONTAINERS OF TRICHLOROISOCYANURIC ACID TABLETS
GAS ANALYSIS (%)
14 Days 28 Days
56 Days
83 Days
EXAMPLE (28 grams)
Cl.sub.2
NCl.sub.3
Total
Total
Total
Total
Cap Bleached (Days)
__________________________________________________________________________
1. MgSO.sub.4 /NaHCO.sub.3 /C
0.01
0.01
0.02
0.01 0.00 0.00 235
5:18:5
Control 3.44
0.87
4.31
3.05 0.88 0.83 7
Comparative Example A
0.15
1.38
1.53
0.48 0.08 6.71 14
NaHCO.sub.3
Comparative Example B
0.43
0.00
0.43
0.33 0.14 0.14 70
MgSO.sub.4
Comparative Example C
0.03
0.21
0.24
0.27 0.06 0.49 70
NaHCO.sub.3 /MgSO.sub.4
14:14
Comparative Example D
0.01
0.00
0.01
0.01 0.15 3.70 70
Carbon (treated)
Comparative Example E
0.01
0.00
0.01
0.35 3.81 -- 56
carbon (untreated)
__________________________________________________________________________
As shown in TABLE 1 above, the novel gas scavenger agent of the
present invention is highly efficient in controlling the amounts of NCl.sub.3
and Cl.sub.2 found in the head gas samples from the containers so that only
minimal amounts are present. In contrast, the control and COMPARATIVE EXAMPLES
permit considerable amounts of the chlorine-containing gases to accumulate
resulting in bleaching of package components such as the container cap as well
as embrittlement and weakening of the polyethylene containers themselves. The
gas scavenging composition of the present invention is surprisingly superior to
the individual components of the mixture as shown by the results of EXAMPLE 1
when contrasted with that of COMPARATIVE EXAMPLES A-E.
EXAMPLE 2
A mixture of anhydrous commercial grade magnesium sulfate, anhydrous
commercial grade sodium bicarbonate and activated carbon was prepared in a
weight ratio of 41 percent of MgSO.sub.4 to 41 percent of NaHCO.sub.3 to 18
percent of C. The mixture (56 grams) was added directly to a plastic container
holding 1816 grams of trichloroisocyanuric acid (TCCA) tablets. An identical
container holding 4 pounds of TCCA tablets, but having no gas scavenging
composition was used as the control. While stored in a controlled atmosphere
maintained at 100.degree. F. and a relative humidity of 85 percent, gases
produced by decomposition of the TCCA were analyzed periodically by the method
of EXAMPLE 1. Gas analysis results are recorded in TABLE 2. After a period of
203 days, the orange color in the top of the cap of the container of EXAMPLE 1
was found to be bleached out. The top of the cap of the container used as the
control had been bleached in only 14 days.
EXAMPLES 3-4
Using
the mixture of EXAMPLE 2, two gas permeable polypropylene scrim packets were
each filled with 28 grams. The packets were heat sealed along the top edge and
each placed in a plastic container of TCCA tablets (1816 grams). The packet of
EXAMPLE 3 was placed near the top of the container of TCCA tablets. In EXAMPLE
4, the packet was placed at the bottom of the container. As the control, an
identical container of TCCA tablets enclosing a polypropylene scrim packet, but
without a gas scavenging composition was used. Gases formed by decomposition of
the TCCA tablets were measured periodically using the method of EXAMPLE 1. Gas
analysis results are recorded in TABLE 2 below.
TABLE II
__________________________________________________________________________
GAS SCAVENGERS FOR CONTAINERS OF TRICHLOROISOCYANURIC ACID TABLETS
GAS ANALYSIS (%) Cl.sub.2 + NCl.sub.3
Days Cap Bleached
Example No. Initial
16 34 51 105
118 150
164
183
203
(Days)
__________________________________________________________________________
2. MgSO.sub.4 /NaHCO.sub.3 /C (56 g.)
-- 0.00
0.00
0.00
0.02
1.74
2.98
4.23
7.33
203
41%41%18%
Control 17.15
6.47
2.42
4.9
2.83
2.54
2.56 16
3. MgSO.sub.4 /NaHCO.sub.3 /C (28 g.)
-- 0.00
0.00
14.6
10.75
6.21 118
41%41%18%
(polypropylene packet
at top of container)
4. MgSO.sub.4 /NaHCO.sub.3 /C (28 g.)
-- -- 0.00
trace
7.69
3.83 150
41%41%18%
(polypropylene packet
at bottom of container)
5. Control 16.10
-- 3.10
5.3
2.98
1.93 16
(polypropylene packet
only)
__________________________________________________________________________
EXAMPLES 5-7
Three mixtures of anhydrous magnesium
sulfate, anhydrous sodium bicarbonate and activated carbon were prepared having
various weight ratios of the components. The weight ratios of MgSO.sub.4
/NaHCO.sub.3 /C were 33%:33%:33%; 18%:64%:18%; and 41%:41%18%. Polypropylene
scrim packets were filled with 7 grams, 14 grams and 28 grams of each of the
mixtures, sealed and enclosed in polyethylene containers holding 1816 grams of
TCCA tablets. The containers were stored in a controlled atmosphere maintained
at 100.degree. F. and 85 percent relative humidity. Using the method of EXAMPLE
1, head gas analyses determined the percentage of NCl.sub.3 and Cl.sub.2 present
after 14 days. The results are as follows:
______________________________________
Wt. Ratio of
MgSO.sub.4 NaHCO.sub.3 /C (%)
Example Wt. of Mixture
33:33:33 18:64:18
41:41:18
No. (grams) Gas Analysis (% NCl.sub.3 + Cl.sub.2)
______________________________________
5 7 16.9 13.3 12.2
6 14 14.7 7.0 0.5
7 28 0.02 0.10 0.03
______________________________________
* * * * *
