U.S. patent number RE32,763 [Application Number 06/901,249] was granted by the patent office on 1988-10-11 for cast detergent-containing article and method of making and using.
This patent grant is currently assigned to Ecolab Inc.. Invention is credited to James L. Copeland, Peter J. Fernholtz, Richard C. Penttila.
United States Patent |
RE32,763 |
Fernholtz , et al. |
October 11, 1988 |
**Please see images for:
( Certificate of Correction ) ** |
Cast detergent-containing article and method of making and
using
Abstract
Solid cast detergent-containing articles are produced for use in
automatic washing machines. A liquid detergent composition is cast
into a mold where it is allowed to solidify. The solid cast
detergent, surrounded on all but its upper surface by the mold, is
used in automatic washing machines having a dispensing device
designed to dispense a liquid aqueous detergent formed from the
solid cast detergent using an impinging liquid spray. The liquid
aqueous detergent flows out of the dispensing device generally
simultaneously with its formation in the dispenser. The cast
detergent composition includes an alkaline hydratable chemical and
optionally further includes one or more preformed cores or plugs
comprising an available chlorine source, a defoamer, or the
like.
Inventors: |
Fernholtz; Peter J.
(Burnsville, MN), Copeland; James L. (Burnsville, MN),
Penttila; Richard C. (East Bethel, MN) |
Assignee: |
Ecolab Inc. (St. Paul,
MN)
|
Family
ID: |
27414427 |
Appl.
No.: |
06/901,249 |
Filed: |
August 27, 1986 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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234940 |
Feb 17, 1981 |
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123956 |
Feb 25, 1980 |
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875784 |
Feb 7, 1978 |
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Reissue of: |
509916 |
Jul 1, 1983 |
04569780 |
Feb 11, 1986 |
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Current U.S.
Class: |
510/225;
134/25.1; 134/29; 134/36; 134/57D; 137/268; 206/524.5; 239/310;
422/261; 422/263; 422/264; 422/278; 510/231; 510/380; 510/438;
510/439; 510/445 |
Current CPC
Class: |
A47L
15/4436 (20130101); B01F 1/0027 (20130101); C11D
17/0052 (20130101); Y10T 137/4891 (20150401) |
Current International
Class: |
A47L
15/44 (20060101); C11D 17/00 (20060101); B08B
003/04 (); C11D 007/06 (); C11D 011/00 (); C11D
017/04 () |
Field of
Search: |
;134/36,25.1,29,57D
;252/90,92,93,99,103,134,135,156,174,DIG.16 ;137/268 ;206/524.5
;239/310 ;422/261,263,264,278 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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715310 |
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Jan 1967 |
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CA |
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0003769 |
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Sep 1979 |
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EP |
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687075 |
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Feb 1953 |
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GB |
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Other References
Fuchs, Polkowski, Cargano, "Agglomerated Automatic Dishwasher
Detergents", Chemical Times and Trends, pp. 37-42 (Oct. 1977).
.
"WARHEAD-Chlorinated Brick Detergents", Model C-14, Warhead Brick
Dispenser. .
"KLENZADE Detergent Bricks", Formulas KDB-3 and KDB-4 (1958). .
"Ecolab-Detergent Concentrated Tank for Use with the Solu-Matic Z4
and Powdered Detergents", Model C-8. .
"Ecolab Detergent Concentrated Tank for Use with the Solu-Matic Z4
and Powdered Detergents", Model C-33. .
"Ecolab Detergent Control and Application Equipment", Models C-11
and C-15. .
"Ecolab Detergent Control and Application Equipment", Model C-11.
.
"Ecolab Detergent Control and Application Equipment", Model
C-4..
|
Primary Examiner: Albrecht; Dennis
Attorney, Agent or Firm: Merchant, Gould, Smith, Edell,
Welter & Schmidt
Parent Case Text
This application is a divisional of Ser. No. 234,940, filed Feb.
17, 1981, which is a continuation-in-part of copending application
Ser. No. 123,956, filed Feb. 25, 1980, now abandoned, which is a
continuation-in-part of application Ser. No. 875,784, filed Feb. 7,
1978, now abandoned. This application also contains subject matter
disclosed in copending application Ser. No. 966,620, filed Feb. 5,
1978, now abandoned.
Claims
What is claimed is:
1. A process for forming a three-dimensional, uniform solidi ,
casti, detergent .Iadd.for ware and hard surface washing
.Iaddend.within a receptacle-shaped mold which comprises:
(a) heating .[.about 20-75 parts by weight of a 40-75 weight
percent.]. .Iadd.an .Iaddend.aqueous solution of an alkali metal
hydroxide .[.to about 55.degree. to 95.degree. C..].;
(b) distributing an effective amount of a hardness sequestering
agent and .[.about 15-40 parts by weight of an.]. .Iadd.additional
solid .Iaddend.alkaline hydratable chemical in said aqueous
solution;
(c) thickening said solution, and mixing said solution during said
thickening to form a castable uniform dispersion;
(d) pouring said uniform dispersion into said receptacle-shaped
mold and at least partly filling said mold; and
(e) allowing said thickened dispersion to solidify in said mold to
a uniform, solid cast detergent wherein at least one surface of the
cast detergent is exposed by the receptacle-shaped mold .Iadd.and
wherein the alkali metal hydroxide and the hardness sequestering
agent are present in amounts sufficient to render the cast
detergent solid at room temperature by virtue of water of
hydration. .Iaddend.
2. The process of claim 1 wherein said alkali metal hydroxide is
sodium hydroxide.
3. The process of claim 2 wherein said hardness sequestering agent
is added to the aqueous solution maintained at a temperature of
55.degree.-.[.70.]..Iadd.85.Iaddend..degree. C. and the hardness
sequestering agent is sodium tripolyphosphate.
4. The process of claim 1 further comprising, following step (d)
and prior to step (e), the step of inserting in said thickened
solution in said mold at least one preformed plug composition.
5. The process of claim 4 wherein at least one preformed plug
composition comprises a source of available chlorine.
6. The process of claim 1 wherein the .Iadd.additional solid
.Iaddend.alkaline hydratable chemical is selected from the group
consisting of anhydrous sodium hydroxide, and combinations of
sodium hydroxide and a sodium condensed phosphate.
7. The process of claim 6 wherein the said alkaline hydratable
chemical is a combination of anhydrous sodium hydroxide and
anhydrous sodium tripolyphosphate.
8. The process of claim 1 wherein the said hydratable material
added is selected from the group consisting of sodium or potassium
.[.trimetaphosphate.]. .Iadd.tripolyphosphate.Iaddend..
9. A solid, cast detergent-containing article produced by the
process of claim 1 comprising:
(a) said solid cast detergent.Iadd.; .Iaddend.and
(b) the mold into which said solid cast detergent was cast, wherein
said mold acts as a container for said cast detergent.
10. A process for forming a three-dimensional, uniform.Iadd.,
.Iaddend.solid.Iadd., .Iaddend.cast detergent .Iadd.for ware and
other hard surface washing .Iaddend.within a receptacle-shaped mold
which comprises:
(a) heating .[.about 20-75 parts by weight of a 40-75 weight
percent.]. .Iadd.an .Iaddend.aqueous solution of an alkali metal
hydroxide to about 55.degree. C. to .Badd..[.95.]..Baddend.
.Iadd.85.Iaddend..degree. C.;
(b) distributing an effective amount of a hardness sequestering
agent and .[.about 15 to 40 parts by weight of an.].
.Iadd.additional solid .Iaddend.alkaline hydratable chemical in
said aqueous solution;
(c) thickening said solution with a polyelectrolyte polymer, to
form a castable uniform dispersion;
(d) pouring said uniform dispersion into said receptacle-shaped
mold and at least partly filling said mold; and
(e) allowing the castable thickened dispersion to solidify in said
mold to a uniform cast detergent, wherein at least one surface of
the cast detergent is exposed by said mold .Iadd.wherein the alkali
metal hydroxide and the hardness sequestering agent are present in
amounts sufficient to render the cast detergent solid at room
temperature by virtue of water of hydration.Iaddend..
11. The process of claim 10 wherein said alkali metal hydroxide is
sodium hydroxide.
12. The process of claim .[.10.]. .Iadd.11 .Iaddend.wherein said
hardness sequestering agent is added to the aqueous solution
maintained at a temperature of
55.degree.-.Badd..[.70.]..Baddend..Iadd.85.Iaddend..degree. C. and
said hardness sequestering agent is sodium tripolyphosphate.
.[.
13. The process of claim 10 further comprising, following step (d)
and prior to step (e), the step of inserting into the castable
thickened solution in said mold at least one preformed plug
composition..].
14. The process of claim 13 wherein at least one .[.of.]. preformed
plug composition comprises a source of available chlorine.
15. The process of claim 10 wherein the said alkaline hydratable
chemical is selected from the group consisting of anhydrous sodium
hydroxide, and combinations of sodium hydroxide and a sodium
condensed phosphate.
16. The process of claim 15 wherein the said alkaline hydratable
chemical is a combination of an anhydrous sodium hydroxide and
anhydrous sodium tripolyphosphate.
17. The process of claim 10 wherein the said hydratable material
added is selected from the group consisting of sodium or potassium
.[.trimetaphosphate.]. .Iadd.tripolyphosphate.Iaddend..
18. A solid, cast detergent-containing article produced by the
process of claim 10 comprising:
(a) solid cast detergent; and
(b) the mold wherein the mold acts as a container for said cast
detergent.
19. A method of making an article of commerce incorporating a
.Iadd.warewashing .Iaddend.detergent composition which
comprises:
(a) forming a castable liquid detergent composition at a
temperature of up to .Badd..[.95.]..Baddend.
.Iadd.85.Iaddend..degree. C. which comprises:
(1) at least 30% by weight of an alkaline hydratable chemical
consisting essentially of alkali metal hydroxide;
(2) an effective amount of a hardness sequestering agent; and
(3) .[.more than 15 parts by weight, per 100 parts by weight of
said alkaline hydratable chemical, of.]. water of hydration, at
least a portion of said water of hydration being associated with
said alkali metal hydroxide .Iadd.wherein the alkali metal
hydroxide and the hardness sequestering agent are present in an
amount sufficient to render the cast detergent a solid at room
temperature by virtue of water of hydration.Iaddend.;
(b) cooling and agitating the liquid composition at a rate such
that the liquid composition thickens without segregation of
components forming a thickened liquid dispersion;
(c) pouring the thickened liquid dispersion into a
receptacle-shaped mold; and
(d) solidifying said liquid dispersion to form a uniform solid
.Iadd.warewashing .Iaddend.detergent composition.
20. The method of claim 19 wherein the mold in which the
composition .[.was.]. .Iadd.is .Iaddend.cast and solidified is a
container for the detergent.
21. The method of claim 20 wherein the article further comprises a
cover attached to the container.
22. The method of claim 19 wherein the article comprises at least
one preformed core .[.surrounded by and in contact with the
detergent on at least one side of the core.]..
23. The method of claim 22 wherein the preformed core comprises a
material selected from the group consisting of a defoamer and a
solid, available chlorine-containing component.
24. The method of claim 23 comprising a plurality of preformed
cores, at least one of which comprises a solid, available
chlorine-containing component.
25. The method of claim 23 wherein the preformed core has been
coated with .[.an inert barrier.]. .Iadd.a .Iaddend.film.
26. The method of claim .[.18.]. .Iadd.19 .Iaddend.wherein said
castable liquid detergent composition comprises:
(a) at least about 30% by weight of an alkaline hydratable chemical
consisting essentially of an alkali metal hydroxide;
(b) effective hardness-sequestering amount of an alkali metal
condensed phosphate;
(c) .[.more than 5% by weight of.]. water of hydration in both
discrete and continuous states of hydration, at least a portion of
said water of hydration being associated with said alkali metal
hydroxide;
(d) .[.up to 15% by weight of a.]. .Iadd.an effective hardness
sequestering amount of an organic .Iaddend.polyelectrolyte; and
(e) up to 5% by weight of an additive selected from the group
consisting of a defoamer and a solid, .[.avaliable.].
.Iadd.available .Iaddend.chlorine-containing component.
27. The method of claim 18 wherein said castable liquid detergent
composition further comprises a sodium silicate. .[.28. A method
for forming an article of commerce incorporating a uniform, cast
detergent composition which comprises:
(a) forming a castable liquid detergent composition at a
temperature of up to 95.degree. C. which comprises:
(1) at least 30% by weight of an alkaline hydratable chemical
consisting essentially of alkali metal hydroxide;
(2) an effective amount of a hardness-sequestering agent;
(3) an effective thickening amount of a polyacrylate; and
(4) more than 15 parts by weight, per 100 parts by weight of said
alkaline hydratable chemical of water of hydration, at least a
portion of said water of hydration being associated with said
alkali metal hydroxide;
(b) cooling the liquid composition to afford a thickened uniform
dispersion; and
(c) casting the uniform dispersion in a receptacle-shaped mold to
yield a solid, uniform detergent composition..]. .[.29. The method
of claim 26 wherein the mold in which the composition was cast and
solidified is a container for the detergent..]. .[.30. The method
of claim 29 wherein the article further comprises a cover attached
to the container..]. .[.31. The method of claim 28 wherein the
article comprises at least one preformed core surrounded by and in
contact with the detergent on at least one side of the core..].
.[.32. The method of claim 31 wherein the preformed core comprises
a material selected from the group consisting of a defoamer and a
solid, available chlorine-containing component..]. .[.33. The
method of claim 32 comprising a plurality of preformed cores, at
least one of which comprises a solid, available chlorine-containing
component..]. .[.34. The method of claim 33 wherein the preformed
core has been coated with an inert barrier film..]. .[.35. The
method of claim 28 wherein said castable liquid detergent
composition comprises:
(a) at least about 30% by weight of an alkaline hydratable chemical
consisting essentially of an alkali metal hydroxide;
(b) an effective hardness-sequestering amount of an alkali metal
condensed phosphate;
(c) more than 5% by weight of water of hydration in both discrete
and continuous states of hydration, at least a portion of said
water of hydration being associated with said alkali metal
hydroxide;
(d) up to about 15% by weight of a polyacrylate; and
(e) up to 5% by weight of an additive selected from the group
consisting of a defoamer and a solid, available chlorine-containing
component..]. .[.36. The method of claim 28 wherein said castable
liquid detergent composition further comprises a sodium
silicate..].
Description
FIELD OF THE INVENTION
This invention relates .Iadd.to .Iaddend.a novel solid cast
detergent-containing article which is particularly useful in
institutional dishwashing machines and industrial washing machines.
Another aspect of this invention relates to a method for producing
the detergent-containing article. Another aspect of this invention
relates to a method for using the detergent-containing article.
Still another aspect of this invention relates to a method for
isolating reactive and incompatible components within a solid cast
detergent to minimize interaction between them during manufacture,
storage, or dispensing.
DESCRIPTION OF THE PRIOR ART
Conventional institutional and industrial spray washing machines
employ liquid or powdered detergents which are generally added to
the wash tank by means of an automatic dispenser system. All forms
of such detergents, whether liquid or solid, have stability
problems and other problems associated with their manufacture,
dispensing, or use. These problems have been discussed extensively
in prior art publications and patent literature, and it is not
practical to do anything more than summarize these discussions. In
the early days of the development of solid detergents, when these
detergent products were relatively low in performance compared to
the products of today, the problems were less severe. However, the
advent of high performance products, stimulated in part by
increased aesthetic and sanitary standards and a demand for shorter
wash times has generally been characterized by the development of
more complex detergent compositions which are more hazardous to the
user, less stable, and more difficult to dissolve in a
satisfactorily uniform manner.
For example, higher performance solid detergents generally means
higher alkalinity (e.g. greater concentrations of sodium
hydroxide)--higher even to the point of posing safety hazards to
the user. Historically, detergents used for warewashing have been
relatively low in alkalinity. The extensive use of aluminum trays
and utensils, the presence of soft metals in wash pump impellers
and other factors generally prevented the use of high alkalinity
detergents. Recently, however, there has been a trend toward the
use of high alkalinity, higher performance products. This trend has
been partially the result of the increased usage of stainless steel
and corrosion resistant plastics in the production of utensils. In
addition, the aforementioned increased standards and shorter wash
times required by the increased volume of business in eating
establishments have created a demand for these higher performance
products. The safety hazard of highly alkaline warewashing
detergents can be high enough to justify extraordinary means for
minimizing contact between the user and the detergent
composition.
In addition to alkali metal hydroxides (e.g. sodium hydroxide),
chemicals used in high performance products, particularly for hard
surface cleaning (e.g. warewashing) include phosphates, silicates,
chlorine containing-compounds, defoamers and organic
polyelectrolyte polymers. See U.S. Pat. No. 3,166,513, issued Jan.
19, 1965 (Mizuno et al). U.S. Pat. No. 3,535,285, issued Oct. 20,
1970 (Sabatelli et al), U.S. Pat. No. 3,579,455, issued May 18,
1971 (Sabatelli et al), U.S. Pat. No. 3,700,599, issued Oct. 24,
1972 (Mizuno et al), and U.S. Pat. No. 3,899,436, issued Aug. 12,
1975 (Copeland et al). The alkali metal hydroxides in these
compositions are very effective in removing most stubborn food
soils, but a source of available chlorine is usually included to
control food strains, such as tea and coffee stains. The defoamer
is usually included to control foam created by a proteinaceous soil
and saponified fats. The use of chlorinated cyanurates as a source
of available chlorine in detergents used to clean hard surfaces is
disclosed in U.S. Pat. No. 3,166,513, issued Jan. 19, 1965 (Mizuno
et al), U.S. Pat. No. 3,933,670, issued Jan. 20, 1976 (Brill et
al), U.S. Pat. No. 3,936,386, issued Feb. 3, 1976 (Corliss et al).
These patents also describe various means for obtaining storage
stable chlorine bearing detergents. The use of defoamers in
detergent compositions is disclosed by U.S. Pat. No. 3,048,548,
issued Aug. 7, 1962 (Martin et al), U.S. Pat. No. 3,334,147, issued
Aug. 1, 1967 (Brunelle et al), and U.S. Pat. No. 3,442,242, issued
May 13, 1969 (Rue et al).
One problem associated with detergents containing both an active
chlorine source and an organic defoamer has been a substantial loss
of available chlorine in a relatively short period of time. This
problem is described in a number of the above references and in the
article by R. Fuchs, J. Polkowski, and Carfagno, "Agglomerated
Automatic Dishwasher Detergents". Chemical Times and Trends, pages
37-42 (October, 1977). One solution to this problem has been to
absorb the organic defoamer onto an inorganic carrier particle,
thus "encapsulating" the defoamer, see U.S. Pat. No. 3,306,858,
issued Feb. 28, 1967 (Oberle). While a chlorine stability problem
is present in low alkalinity detergents containing defoamers, the
problem is more acute with high alkalinity detergents because many
defoamers and chlorine-containing compounds are not stable in the
presence of highly alkaline chemicals such as sodium hydroxide.
In addition to the chlorine stability problem, several additional
problems have existed with high performance powdered detergent
compositions which have been used in institutional and industrial
washing machines. One of these problems has been caused by
differential solubility of the detergent components. Not all of the
components of standard detergents dissolve at the same rate or have
the same equilibrium solubilities. For example, a fine, soluble
particle such as sodium dichloroisocyanurate dihydrate, a common
source of available chlorine, may dissolve more rapidly than some
hardness sequestrants of surfactants, i.e. common detergent
component. Thus, when a dispenser is charged with a powdered
detergent containing both of these components, the first effluent
from the dispenser will usually be overrich in available chlorine
while the last effluent before the dispenser is recharged will
usually be poor in available chlorine.
Another type of differential solubility problem exists with many
common defoamers. Many defoamers have an oily consistency and are
sparingly water soluble. When detergents containing these defoamers
are dispensed from a conventional water-in-reservoir dispenser, the
oily defoamer floats to the top and feeds the wash tank in an
erratic fashion.
Another problem may exist with a powdered detergent if its
components are of different particle sizes and densities.
Variations in particle size and density between components may lead
to segregation during manufacturing, shipping, and handling. Even
when uniform distribution can be achieved during manufacturing,
handling and shipping may cause segregation. Segregation leads to
non-uniformity in the composition of the detergent when it is
withdrawn from the container. Agglomeration of the components has
been used to minimize the segregation problem. However, the use of
agglomeration usually requires recycling of any particles which are
too large or too small, which can be a significant percentage of
the product.
As noted previously, it is desirable for safety and convenience to
minimize contact between the user and the high-performance or
highly alkaline detergent composition, and such lessened contact
can be one of the many benefits of automatic dispensing. In the
case of liquid detergents, it is relatively easy to provide an
automatic dispensing system and method. For example, liquid
detergents can simply be pumped into the wash tank or reservoir
directly from their shipping containers.
Solid detergents (which can be in briquette, or, most typically, in
powdered form) present much more complicated automatic dispensing
problems. Several approaches have been devised for .[.attaching.].
.Iadd.attacking .Iaddend.these problems--that is, for utilizing
solid phase detergents without losing the benefits of automatic
dispensing. In one approach, detergents used in large conveyor type
machines are dispensed directly from their shipping containers by
means of a dispensing system similar to that described in U.S. Pat.
No. 3,595,438, issued July 27, 1971 (Daley et al). The shipping
container is inverted and placed over a detergent dispenser
reservoir and a water spray is used to dissolve the detergent from
the drum as needed. A system for dissolving powdered detergent from
a five to ten gallon capacity shipping pail is also known, see U.S.
Pat. No. 4,020,865, issued May 3, 1977 (Moffat et al). In short,
the solid powdered detergent in the shipping container is not in a
form which normally would be introduced directly into the wash tank
of the washing machine, and it is generally preferred in the art to
convert the powder into a liquid, e.g. by dissolving the powder
with water in a special apparatus designed to carry out the
dissolving step.
The dissolving apparatus need not be physically remote from the
washing machine. Indeed, it is common practice to mount
dissolving/dispensing devices directly above--or on the side wall
of--the wash tank of the machine. One typically used type of
machine-mounted dispenser is the so-called water-in-reservoir type.
(The water-in-reservoir approach is not limited to machine-mounted
dispensers, however; in machine-mounted applications, the
water-in-reservoir dispenser is generally used in single tank
warewashing machines.) Typically, the water-in-reservoir type of
dispenser makes up a concentrated solution of detergent from the
powder in the reservoir by means of swirling action or agitation
provided by incoming water. The concentrated solution is delivered
directly to the wash tank by gravity or through a delivery tube.
The concentration of the detergent in the wash tank can be
maintained at a present level by means of a conductivity sensing
controller similar to that described in U.S. Pat. No. 3,680,070,
issued July 25, 1972 (Nystuen).
Various other types of devices will dissolve and dispense powdered
detergents and can be mounted directly on the washing machine. For
example, U.S. Pat. No. 4,063,663, issued Dec. 20, 1977 (Larson et
al) described a type of dispenser in which the powdered detergent
is placed over a conical or hemispherical screen and an aqueous
spray from beneath the screen is used to dissolve the detergent.
The concentrated solution produced by the spray is collected and
directed to the wash tank. The dispenser differs from the
water-in-reservoir type in that there is no water standing in the
powder dispenser and the bulk of the powder remains dry. Otherwise,
this type of dispenser operates in a manner similar to the
water-in-reservoir type.
Among the other types of powdered detergent dispensers are small
dispensers which hold from four to six pounds of detergent. The
hopper of such dispensers can be filled from detergent-containing
drums by means of a scoop or by the use of small individual (i.e.
two pound) pouches of detergent. Dispensing systems for washing
systems consisting of multiple hoppers which are filled with
different chemicals or mixtures of chemicals are also known.
Dispensing system for dispensing briquettes of detergent are also
known in the art. See U.S. Pat. Nos. 2,382,163, 2,382,164,
2,382,165 all issued Aug. 14, 1945 to MacMahon and U.S. Pat. No.
2,412,819, issued Dec. 17, 1946 (MacMahon). The detergent
briquettes are dispensed from a modified water-in-reservoir round,
pot-shaped dispenser. The briquettes (usually three) are held in a
mesh basket which forms a slot about 11/4 inches wide across the
diameter of the pot. The dissolving action is provided by a stream
of water directed against the lower-most briquette and from the
swirling action of water around the submerged portion of the
lowermost briquette. Like the water-in-dispenser type devices,
water is left standing in the reservoir. This type of system has
the advantage of making it visually possible to determine when the
detergent dispenser reservoir needs replenishing.
The MacMahon patents also disclose detergent briquette compositions
and methods of manufacturing the briquettes. The briquette
compositions and the methods of manufacture which are disclosed
appear to require the presence of a silicate and trisodium
polyphosphate or sodium carbonate. Detergent bars of cakes
comprising a significant level of an organic detergent and
tripolyphosphates are also known. See U.S. Pat. No. 3,639,286,
issued Feb. 1, 1972 (Ballestra et al). Compressed tablets
containing detergents are also known, see U.S. Pat. No. 2,738,323,
issued Mar. 14, 1956 (Tepas, Jr.) and U.S. Pat. No. 3,417,024,
issued Dec. 7, 1968 (Goldwasser).
In the field of dispensing solid detergent .[.to.]. .Iadd.into
.Iaddend.conventional institutional and industrial washing machines
for spray cleaning of hard surfaces (e.g. warewashing), the
briquette detergent approach does not appear to have attained the
same degree of commercial success as powdered detergents.
When one leaves behind the field of high performance or highly
alkaline detergents, one finds that a variety of dispensers and
containers for ordinary soap, compressed detergent, powder, or the
like have been disclosed. See, for example, U.S. Pat. Nos.
2,686,080 (Wood), issued Aug. 10, 1954 and 2,920,417 (Wertheimer),
issued January, 1960.
SUMMARY OF THE INVENTION
It has now been found that the chlorine stability, differential
solubility, segregation, and safety problems described above can be
minimized by forming a solid cast detergent in a disposable mold
and dispensing or using the detergent directly from the mold/cast
detergent combination. That is, the combination of the cast
detergent and the disposable mold in which it was formed provides
an article of commerce capable of dispensing dissolved solids from
substantially only one surface--the surface which was the free or
unsupported surface in the mold. This detergent article can be
designed or structured to further minimize chlorine stability and
differential solubility problems, e.g. by including the chlorine
source and/or the defoamer as preformed plugs or cores encased in
the cast detergent composition.
Thus, the present invention involves a process for forming and a
method for using a three-dimensional, solid cast detergent
composition containing an alkaline hydratable solid component, at
least one other solid component, and a receptacle-shaped mold
surrounding and containing the detergent composition on all but one
surface. The detergent composition is normally formed by mixing and
heating the components in an aqueous solution, thickening the
solution and preferably also cooling it, pouring the solution into
a mold, and allowing the mixture to solidify, it being understood
that the solidification can involve one or more physico-chemical
mechanisms, including "freezing", precipitation from solution, etc.
The aforementioned preformed plugs or cores of additional
components can be inserted in the mixture after it has been added
to a mold and before it has solidified.
The cast detergent composition is preferably left in the disposable
mold in which it was cast. Alternatively, the cast detergent can be
demolded and inserted in an inexpensive container or receptacle
which has substantially the same configuration as the mold, since
in either case the cast detergent is surrounded on all but one
surface, as described previously. The thus-surrounded cast
detergent isused by placing its exposed surface in a drainable
position (preferably fixed) within a detergent dispensing
apparatus. A fixed drainable position is one in which the
aforementioned unsurrounded, exposed surface is fixed with respect
to the horizontal and a potential impinging spray of liquid such
that the unsurrounded, exposed surface permits gravity flow
therefrom, either because of an inclination from the horizontal by
a few degrees (e.g. by 10.degree.-90.degree. ) or by inclination
beyond 90.degree., i.e. partial or total inversion up to and
including a totally inverted or downward-facing position. A spray
of liquid impinging on the drainable (inclined or inverted)
surface, suitably controlled in duration, provides a draining
action or gravity flow of liquid detergent which drains downward
off of the drainable surface to the washing machine into which the
detegent is to be dispensed. Control over the duration of
impingement (hence the duration of downward flow) has the effect of
controlling the concentration of detergent in the washing machine.
The dispensing apparatus is not a water-in-reservoir type, since it
dispenses the flow of liquid detergent about as fast as this flow
is formed by the spraying action.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial cut-away side view of a disposable mold
containing the cast detergent of this invention.
FIG. 2 is a cross-sectional view of a disposable mold containing
the cast detergent of this invention. The cast detergent includes a
preformed plug or core comprised of an additional ingredient or
ingredients.
FIG. 3 is a plan view of the article illustrated in FIG. 2.
FIG. 4 illustrates the article of FIGS. 2 and 3 placed in an
apparatus for dispensing the detergent composition.
FIG. 5 is a graph comparing the chlorine recovery for a cast
detergent prepared according to this invention versus a
conventional powdered detergent.
FIG. 6 is a view in perspective of a solid detergent dispenser
constructed according to the principles of this invention.
FIG. 7 is an exploded view in perspective of one embodiment of the
cartridge-type receptacle member for holding a charge of solid
block detergent, as disclosed in FIG. 6.
FIG. 8 is a view in front elevation with portions thereof broken
away, of the solid detergent dispenser disclosed in FIG. 1.
FIG. 9 is a sectional view of the solid detergent dispenser
disclosed in FIG. 9, taken generally along the line 9--9 of FIG.
8.
DETAILED .[.DESCTIPTION.]. .Iadd.DESCRIPTION .Iaddend.
Raw Materials
One necessary component for producing cast detergent compositions
of the present invention is a hydratable chemical. The term
"hydratable chemical" as used herein includes chemicals forming
both discrete and continuous states of hydration and thus means a
chemical which is capable of absorbing or combining with water
(e.g. 0.2-20 moles of water per mole of chemical) to form either
type or state of hydration. The hydratable chemical will normally
be alkaline, that is, a one weight-percent aqueous solution of the
chemical will have a pH of greater than 7.0 at 23.degree. C. Since
the detergent compositions used in this invention are highly
alkaline, it is preferred that the hydratable component of the
composition be alkaline in nature. Hydratable chemicals useful in
the practice of this invention include alkali metal hydroxides,
such as sodium hydroxide and potassium hydroxide; silicates, such
as sodium metasilicate; phosphates, particularly phosphates of the
formula M--PO.sub.3 M).sub.n OM or the corresponding cyclic
compounds ##STR1## wherein M is an alkali metal and n is a number
ranging from 1 to about 60, typically less than 10 for cyclic
phosphates, typical examples of such phosphates being sodium or
potassium orthophosphate and alkaline condensed phosphates (i.e.
polyphosphates) such as sodium or potassium pyrophosphate, sodium
tripolyphosphate, sodium hexametaphosphate, etc.; carbonates such
as sodium or potassium carbonate; borates, such as sodium borate;
etc. Combinations of two hydratable chemicals, for example, sodium
hydroxide and sodium tripolyphosphate, and combinations of alkaline
condensed phosphates with organic sequestering agents and/or alkali
metal hydroxides have been found to work particularly well in the
practice of this invention.
A second necessary component of the detergent compositions of this
invention is water. Water is used to form a uniform medium
(solution or dispersion) containing the detergent components; the
uniform medium being cast into a mold and solidifying by a
solidification mechanism described previously. Water may be added
as a separate ingredient or in combination with one of the other
components, for example as an aqueous solution of 50% sodium
hydroxide.
To obtain the advantages of this invention, at least two solid
components are needed. If only one solid component were used,
differential solubility and segregation problems would not exist
and there would be few advantages to forming a cast composition.
The advantages of a cast detergent composition over a conventional
powdered detergent composition are described more fully
hereinafter.
In addition to those components previously described, other
conventional detergent components and fillers can be included. For
example, it is common to include a source of available chlorine and
a defoamer. Many chlorine sources can be used including chlorinated
isocyanurates, such as sodium dichloroisocyanurate dihydrate, and
hypochlorites, such as calcium and lithium hypochlorite. As more
fully hereinafter described, when an available chlorine containing
component is included in the composition of this invention it is
preferably incorporated in the composition as a preformed plug or
core. Defoamers are also normally included in a detergent
compositions. Typically, a "defoamer" is a chemical compound with a
hydrophobe/hydrophile balance suitable to reducing the stability of
protein foam. The hydrophobicity can be provided by an oleophilic
portion of the molecule (e.g. an aromatic alkyl or aralkyl group;
an oxypropylene unit or oxypropylene chain, or other oxyalkylene
functional groups other than oxyethylene, e.g. tetramethylene
oxide). The hydrophilicity can be provided with oxyethylene units
or chains or blocks and/or ester groups (e.g. organophosphate
esters), salt-type groups, or salt-forming groups. Typically,
defoamers are nonionic organic surface-active polymers having
hydrophobic groups or blocks or chains and hydrophilic
ester-groups, blocks, units, or chains, but anionic, cationic, and
amphoteric defoamers are known. For a disclosure of nonionic
defoaming surfactants, see U.S. Pat. No. 3,048,548, issued Aug. 7,
1962 (Martin et al), U.S. Pat. No. 3,334,147, issued Aug. 1, 1967
(Brunelle et al), and U.S. Pat. No. 3,442,242, issued May 13, 1969
(Rue et al). Phosphate esters are also suitable, e.g. esters of the
formula RO--PO.sub.3 M).sub.n R, wherein n is as defined previously
and R is an organic group or M (as defined previously), at least
one R being an organic group such as oxyalkylene chain. If a
defoamer is included it may be included as a preformed plug or
core, as more fully described hereinafter. If it is included as a
preformed core or plug it must be a solid, or be capable of being
combined with other components to form a solid, at room
temperature. Wax-like materials can be used to further isolate the
chlorine source or defoamer in the core from the surrounding cast
article.
THE DETERGENT COMPOSITION
The hydratable chemical or combination of hydratable chemicals will
normally comprise at least 30%, and preferably 60%, by weight of
the cast detergent composition. The water of hydration will
normally comprise more than 5 weight-% (e.g. 10-35 weight-%) of the
cast detergent composition. Stated another way, the water of
hydration can comprise more than about 15 parts by weight per 100
parts by weight (15 phr), e.g. 25-90 phr, of the hydratable
chemical or combination of chemicals. Performance-improving
additives such as available chlorine producing components and
defoamers will normally comprise minor amounts of the composition,
that is, less than 5%. As will be explained subsequently, the cast
detergent composition can also contain a polyelectrolyte.
Typical three-component compositions of this invention can be
formulated from (1) a phosphate or other hardness-precipitating or
hardness sequestering agent, (2) an alkali metal hydroxide, and (3)
water. Typical four or five component compositions would further
include a defoamer and/or a neutral inorganic salt (alkali metal
halides, sulfates, etc.) and/or a chlorine source and/or a
thickening agent, thixotrope, suspending agent or organic chelating
or sequestering agent, or the like.
Typical detergent compositions of this invention employ a condensed
alkali metal phosphate for the sequestering of hardness (Mg++and
Ca++ions). However, organic chelating or sequestering agents
(citric acid, polyelectrolytes such as the polyacrylates of
molecular weight 1000-3000, etc.) have been used as alternatives to
or in combination with the condensed phosphates; see, for example,
U.S. Pat. No. 3,535,285, issued Oct. 20, 1970 (Sabatelli et al),
U.S. Pat. No. 3,579,455, issued May 18, 1971 (Sabatelli et al),
U.S. Pat. No. 3,700,599, issued Oct. 24, 1972 (Mizuno et al), and
U.S. Pat. No. 3,899,436, issued Aug. 12, 1975 (Copeland et al). As
is known in the art, polyacrylates (particularly alkali metal salts
of polyacrylic acid and its copolymers) can function as thickeners
in aqueous systems. Cast detergent compositions of this invention
can contain up to 15% by weight of polyelectrolytes, as the sole
sequestering agent or in combination with alkali metal condensed
phosphates.
One embodiment of the solid, cast detergent-containing article of
this invention is generally shown by 1 in FIGS. 1 through 3. The
article includes .Iadd.a .Iaddend.disposable container or mold 3
into which base detergent 2 was cast or allowed to solidify. During
shipping, article 1 will normally include lid or cover 5. Lid or
cover 5 can be made of the same or similar material as used to make
mold 3. As will be explained subsequently, this material is
ordinarily alkaline-resistant, non-breakable, and inexpensive.
Expensive corrosion-resistant metals or plastics can be used, if
provision can be made for their recycling, but "disposable"
materials would normally be preferred for most institutional uses.
As illustrated in FIG. 2, the cast detergent composition is
surrounded by and in contact with mold 3 on all but the upper
surface of the solid cast detergent. A cross-section of the solid
cast detergent 2 can be more than a centimeter thick (e.g. 2-20 cm
thick). The area of the upper surface can easily exceed 100
cm.sup.2, e.g. 125 cm.sup.2 to 1000 cm.sup.2 or more. Unlike
compressed detergent tablets, it has been found that cast detergent
blocks can be made very large-almost any desired size.
In one embodiment of this invention, cast detergent base 2 will
include one or more preformed plugs or cores 6, as illustrated in
FIGS. 2 and 3. At least one preformed plug will normally comprise a
chlorine source. When a plurality of preformed plugs are used they
will normally comprise different, incompatible ingredients. For
example, one plug could comprise a chlorine source while a separate
plug could comprise a defoamer. By incorporating a chlorine source
in one preformed plug and a defoamer in a separate preformed plug,
degradation of the chlorine source, and the resultant loss of
available chlorine, which often occurs when chlorine sources and
defoamers come in contact, can be minimized. Thus, by incorporating
preformed plugs of incompatible ingredients in the solid, cast
detergent composition of this invention, the stability problems
associated with many conventional powdered detergents can be
minimized. To minimize reactivity between the base detergent and
any material added as preformed cores, the core material may be
optionally encased in a film or material which would not react with
the core material or the detergent base. This coating could be
comprised of a natural wax, a synthetic wax, a phosphate ester, or
the like.
Some active chlorine sources such as calcium hypochlorite have been
found to react very slowly at the plug-base detergent interface and
would not normally need to be encased in a film or the like.
However, other chlorine sources such as sodium dichloroisocyanurate
dihydrate have been found to be more reactive, in which case a
protective film would be beneficial.
Mold or container 3 can be made of any alkali-resistant material
which can withstand moderately elevated temperatures, e.g.
150.degree. F., and which can be formed into and hold the desired
shape. Since the mold is generally intended to be "disposable"
(i.e. not intended for re-use as a mold), inexpensive materials are
preferred such as thermoplastics, resin-impregnated heavy paper or
cardboard, and the like. Inexpensive but fragile material such as
glass or ceramics are less preferred due to handling or shipping
problems, relatively flexible materials being preferred. Molds made
of plastic (e.g. inexpensive thermoplastics) have been found to be
particularly useful.
The solid, cast detergent-containing article of FIGS. 1-3 can be
used as illustrated in FIG. 4. FIG. 4 illustrates detergent
dispensing apparatus 10 which can be part of a conventional
institutional or industrial washing machine (not shown). Article 1,
including base detergent 2, preformed core 6, and container 3 is
placed in a totally downward-facing or totally inverted position
over spray means 12 which is connected to a water source 14,
whereby the exposed surface of detergent 2 becomes a drainable
surface. When water source 14 is turned on, spray means 12 causes
water to impinge on the exposed surface of detergent 2 and core 6.
The detergent and the core dissolve, creating a gravity flow of
liquid aqueous detergent which flows downwardly through pipe 13 to
the wash tank or washing zone of the washing machine (not shown).
Detergent base 2 and preformed core 6 can be formulated to dissolve
at substantially the same rate and thus supply the tank with a
consistent ratio of ingredients.
By controlling the spray time the amount of detergent, and thereby
the concentration of detergent, in the wash can be controlled. In
other words, the liquid aqueous detergent formed as a result of the
impingement of the spray on the exposed surface of detergent 2
flows by gravity into pipe 13 generally simultaneously with its
formation within dispensing apparatus 10. Standing water or aqueous
liquid is not permitted to accumulate within dispensing apparatus
10.
Referring to FIGS. 6 through 9 there is generally disclosed at 20 a
detergent dispenser for solid detergent compositions of the
block-type, generally constructed according to the principles of
this invention. That embodiment of the dispenser 20 illustrated in
these Figures is one of the type suitable for servicing relatively
smaller wash applications, wherein the detergent dispenser is
generally mounted directly to the washing machine or immediately
adjacent thereto, such that the concentrated detergent solution
formed by the dispenser apparatus will flow by gravity into the
wash tank of the washing machine proper (not illustrated).
The dispenser 20 has a housing portion 21, constructed of any
suitable material capable of withstanding exposure to highly
caustic detergent solutions, and is preferably configured of
stainless steel or molded plastic material. The housing 21 has a
generally planar back wall 21a suitable for direct engagement with
and mounting to a vertical mounting surface or wall (not shown).
The back wall 21a includes a plurality of mounting slots 22 formed
therethrough, to enable fixed mounting of the housing 21 to a solid
vertical surface such as a vertical wall of a washing machine or a
vertical wall disposed adjacent a washing machine.
The housing 21 defines a substantially enclosed inner cavity 30.
For ease of reference and distinguishing the various portions of
the inner housing cavity 30, referring to FIG. 9, the upper portion
of the inner cavity will be referred to as the spray region 30a of
the cavity, and the lower portion of the inner cavity 30 will be
referred to as the collector or discharge region 30b thereof, it
being understood that gravity flow prevents detergent liquid from
standing or accumulating in the collector or discharge region
30b.
The upper portion of the housing 21 defines a mouth or access port
32 opening into the inner cavity 30. Discharge region 30b includes
a hose clamp extension 35 (FIGS. 8 and 9) which defines a
passageway or discharge port 34 (FIG. 8) through the housing 21 for
concentrated detergent solution collected or accumulated within the
discharge region 30b of the inner cavity 30 of the housing 21. The
hose clamp extension 35 has a plurality of annular ribs configured
for engaging the inner walls of a connecting conduit or hose (not
illustrated), for directing fluid flow from the discharge port 34
(FIG. 8).
An upper front wall 21b of the housing 21 projects downwardly from
the access port 32 at an inclined angle to the horizontal. In the
embodiment of the invention illustrated in FIGS. 6-9, the upper
front wall 21b forms an angle of approximately 60 degrees with the
horizontal. The upper front wall 21b terminates at and is
continuous with a first lower wall 21c of the housing 21, which is
also slightly inclined with respect to the horizontal and lies in a
plane generally parallel to that of the upper front wall 21b. The
lower front wall 21d terminates at and is continuous with a bottom
wall 21e (FIG. 9) of the housing. In FIG. 9, the bottom wall 21e is
generally planar, however the bottom wall 21e could assume many
different configurations (such as ramp-shaped or funnel-shaped),
and is generally configured so as to direct downward any detergent
solution formed within cavity 30 by the impingement action of the
liquid spray from nozzle 61 (FIG. 9) on surface 100a of cast solid
block detergent 100 (FIG. 9) into discharge port 34.
The back wall 21a extends between the bottom wall 21e and an upper
wall, generally designated at 21f, which extends to and defines one
edge of the access port 32. When viewed in cross-section as in FIG.
9, that region of the inner cavity 30 generally located between the
upper front wall 21b, the first lower wall 21c and the back wall
21a and the upper wall 21f comprises the upper spray region 30a;
whereas that region of the inner cavity 30 generally located
between the lower front wall 21d and the back wall 21a, and
extending down to the bottom wall 21e generally comprises the
discharge region 30b.
The housing 21 further has a pair of oppositely disposed side walls
21g, each configured to define a flange or land region 24 extending
into the inner cavity 30 in generally parallel spaced relationship
to one another. The land regions 24 are disposed to extend from the
access port 32 downwardly to the bottom wall 21e, and cooperatively
form with the front wall 21b oppositely disposed channels or races
within the inner cavity 30 for slidably retainably engaging a
cartridge member 40.
One embodiment of a cartridge member 40 suitable for removable
insertion within the access port 32 of the dispenser 21 is
illustrated in more detail in FIG. 7. Referring to FIG. 7, the
cartridge 40 is basically a receptacle or container-shaped member
suitable for retainably holding in fixed position relative thereto
a cast solid block of solid detergent composition. The cartridge
member 40 generally comprises a bottom surface 41, a lower
peripheral side wall portion 42, an intermediate ledge region 43
and an upper peripheral side wall portion 44. The lower peripheral
side wall portions 42 extend between the bottom surface 41 and the
intermediate ledge region 43, with all except one surface of the
lower peripheral side walls (that surface designated as 42a) being
disposed generally perpendicular to the bottom surface 41. The
non-perpendicular lower peripheral side wall portion 42a is
configured to define an angle with the bottom surface 41
corresponding to the included angle defined between the upper front
wall 21b and the first lower wall 21c of the dispenser housing 21
(see FIG. 9). The fourth side of the upper peripheral side wall 44a
forms an included angle with the general plane of the intermediate
ledge region 43 substantially equal to that of the included angle
formed between the lower front wall 21d and the bottom wall 21e of
the dispenser housing 21 (see FIG. 10).
The 43a portion of the intermediate ledge region is somewhat wider
(as measured between corresponding upper and lower peripheral side
wall portions) than the width of the intermediate ledge region 43
of the other portions of the cartridge member 40. A plurality of
raised land areas or mounting surfaces 45 project upwardly from the
intermediate ledge region 43a, the upper surfaces respectively
thereof lying generally in a common plane.
The lower peripheral side walls 42 and 42a cooperatively define
with the bottom surface 41 a first receptacle-shaped container 46
for retainably holding a geometrically shaped volume or mass of
cast solid detergent composition 100 (see FIG. 9). The elongated
intermediate ledge region 43a defines the bottom surface of a
second receptacle-shaped container, generally designated .[.at.].
.Iadd.as .Iaddend.47 (see FIGS. 7 and 9). A screen or mesh member
50 is configured for mounting to the intermediate ledge region 43
(other than at the extended intermediate ledge region 43a) and to
the raised mounting surfaces 45, in spaced relationship to the
underlying extended intermediate ledge region 43a, so as to overlie
respectively the first and second receptable-shaped container
regions 46 and 47. In the preferred embodiment of the invention,
the first receptacle-shaped container 46 retainably holds a solid
block of detergent composition which was cast directly into the
receptacle-shaped container portion 46 of the cartridge member 40,
the container portion 46 physically forms the mold in which the
solid cast detergent 100 (FIG. 100) is manufactured. The retainably
held charge of solid detergent 100 within the container portion 46
of the cartridge member 40 defines a broad, generally planar upper
surface 100a (FIG. 9) lying generally in the same plane as the
intermediate ledge region 43 or slightly there below. The upper
detergent surface 100a is inclined from the horizontal (hence
"drainable") and is disposed for exposure to spray from a nozzle
means, hereinafter described in more detail.
The screen member 50 has a first generally planar portion 50a (FIG.
7), a second generally planar portion 50b and an interconnecting
wall portion 50c. The first screen portion 50a is sized to fit
between the opposing upper peripheral side walls 44 and is
configured for mounting to the three contiguous portions of the
intermediate ledge regions 43, exclusive of ledge region 43a, for
substantially overlying the first receptacle-shaped container
portion 46 of the cartridge member 40. The second portion 50b of
the screen member 50 lies in a plane generally parallel to and
spaced above that of the first screen portion 50a, and is
configured for mounting to the plurality of raised mounting
surfaces 45 so as to substantially overlie the extended
intermediate ledge region 43a and the second receptacle-shaped
container region 47 of the cartridge member 40. The interconnecting
wall portion 50c of the screen member 50 forms included angles with
the first and second 50a and 50b portions of the screen member 50,
substantially the same as those included angles which the lower
peripheral side wall portion 42a forms with the bottom surface 41
and with the intermediate ledge region 43a of the cartridge member
40. When mounted to the cartridge member 40, the interconnecting
wall portion 50c of the screen member 50 forms included angles with
the first and second 50a and 50b poritons of the screen member 50,
substantially the same as those included angles which the lower
peripheral side wall portion 42a forms with the bottom surface 41
and with the intermediate ledge region 43a of the cartidge member
40. When mounted to the cartridge member 40, the interconnecting
wall portion 50c of the screen member 50 lies generally co-planar
with the lower peripheral side wall portion 42a, and operatively
forms an extension thereof, to define with the extended
intermediate ledge region 43a and the upper peripheral side wall
portion 44a and those oppositely disposed portions of the upper
peripheral side wall 44 lying contiguous with the extended
intermediate ledge region 43a, the second receptacle-shaped
container 47.
The cartridge member 40 may be constructed of any suitable material
that is capable of withstanding exposure to highly caustic
detergent solutions, and is preferably configured of molded plastic
material such as polyethlene or polypropylene. The cartridge member
can be supplied with solid block detergent and sold as an article
of commerce, wherein the entire cartridge member 40 or portions
thereof can be discarded after the detergent charge retainably held
thereby has been exhausted. When the cartridge member is a
disposable item, the screen member 50 would be permanently welded
or bonded to the intermediate ledge region 43 and the plurality of
raised land areas 45.
Alternatively, the cartridge member 40 could be a re-usable item,
possibly constructed of stainless steel, wherein the screen member
50 could be detachably secured to the underlying cartridge member
40 so as to enable re-charging of the solid block detergent
retainably held by the various receptacles of the cartridge member.
The screen member 50 may be of any suitable material capable of
withstanding exposure to highly caustic detergent solutions, and is
in the preferred embodiment, preferably constructed of a plastic
material. The mesh size of the screen member 50 is configured so as
to be small enough to prevent solid particles of the solid block
detergent held by the receptacle-shaped containers of the cartridge
member 40 from passing therethrough, yet must be large enough so as
to permit relatively unobstructed passage therethrough of a
pressurized spray pattern directed at the undelying exposed
surfaces of the solid block detergent. In general, the mesh size of
the screen member 50 should be no larger than the largest dimension
of the discharge port 34, so as to prevent any solid chunks or
pieces of the solid block detergent which would pass therethrough
from clogging the free flow of concentrated detergent solution
through the discharge port 34.
The first receptacle-shaped container 46 of the cartridge member 40
can be configured to hold the solid cast detergent composition of
this invention. The second receptacle-shaped container 47 can, if
desired, be configured for retainably holding a long narrow block
of a second solid block detergent composition (not shown).
Preferably, however, container 47 is configured to hold a plurality
of pillow-shaped pieces, briquettes, tablets or pellets of
detergent ingredients such as a chlorine source or a defoamer of
the type described herein, particularly in those cases wherein a
defoamer and/or chlorine-releasing agent plug has not been inserted
into the cast detergent 100. The briquette or tablet form of the
detergent ingredients retainably held by the second
receptacle-shaped container 47, is illustrated at 103 in FIG. 9. It
is to be understood that, in the event that a chlorine-releasing
and/or defoamer plug or plugs were inserted in cast detergent 100,
container 47 could be left empty.
In the embodiment of the detergent dispenser disclosed in FIGS.
6-9, the height and width of the cartridge member 40) are sized for
cooperative insertion within the access port 32 of the housing 21,
as illustrated in FIG. 6, whereby cartridge member 40 can be placed
in a fixed pre-determined position with respect to the housing, (as
indicated in FIG. 9). When disposed in such fixed, pre-determined
resting position, upper detergent surface 100a (the only surface of
cast solid detergent 100 which is not surrounded by the walls of
cartridge member 40) is exposed to any spray which may emerge from
spray-forming nozzle 61. Referring to FIGS. 9 and 6, a conduit
member 60 is secured to the upper wall 21f of the housing 21 and
projects therethrough into the upper spray region 30a of the inner
cavity 30. The spray-forming nozzle 61 is threaded or otherwise
properly secured to that end of the conduit 60 extending into the
inner cavity 30 and is disposed therein, so as to project a spray
pattern of pre-determined shape at substanially the entire
respective exposed solid detergent block surfaces of the detergent
within the various receptacle chambers of the cartridge member 40.
The nozzle 61 is oriented, relative to the "fixed" position of the
cartridge member 40 within the inner cavity 30, such that the
longitudinal spray axis 62 from the nozzle is disposed generally
perpendicular to the broad "drainable" exposed upper surface 100a
of the solid block detergent volume 100. The spray nozzle may be of
any suitable configuration and construction for projecting a
pressurized spray of aqueous liquid (preferably water) received
through the conduit 60, in a pre-determined pattern, configured to
directly impinge upon substantially the entire exposed surfaces of
the solid block detergent retainably held by the cartridge member
40. In that embodiment of the invention disclosed in the Figures,
the particular spray nozzle produces a "square" spray pattern (as
viewed in a plane generally perpendicular to the longitudinal spray
axis 62) for directing the spray pattern ejected therefrom at
substantially the entire drainable exposed surface 100a as well as
at the exposed surface or surfaces of the solid block detergent
retainably held by the second receptable-shaped container 47. The
water supply conduit 60 passes through a siphon breaker 63 (FIG. 6)
and is connected, in operation, to a suitable pressurized source of
water (not shown), generally ranging between 5 and 70 psi.
A safety switch configuration is mounted within the housing 21 for
sensing the operative position of the cartridge member 40 within
the inner cavity 30, including a reed switch member 70, mounted in
a fixed position by means of a mounting bracket 71 (see FIG. 9).
Side wall portion 44a of the cartridge 40 contains an encapsulated
magnet 72 (FIGS. 7 and 9). The positions of magnet 72 and the reed
switch 70 are such that the reed switch 70 is activated by the
magnetic flux of the magnet 72 only when the cartridge member 40
has been fully accepted into the inner cavity 30 of the dispenser
21 in its pre-determined fixed position (as illustrated in FIG. 9),
whereby the access port 32 of the housing 21 is substantially
closed by the positioned cartridge member 40. As the magnet 72 is
withdrawn out of activating proximity with the reed switch 70, the
reed switch changes its energization state, providing an
appropriate energizing (or de-energizing) signal to a valve (not
shown) to block pressurized fluid flow through the conduit 60 to
the nozzle 61.
Once the cartridge member 40 is properly inserted at its fixed
pre-determined position within the inner cavity 30, the masses or
volumes of cast detergent or detergent ingredients retainably held
by one or more of the various receptacles within the cartridge 40
are dissolved at a pre-determined rate, by the pressurized
impinging flow of aqueous liquid from the nozzle 61. A pressurized
source of water is provided to the nozzle 61 as commanded by
appropriate control means within the washing machine proper which
the detergent dispenser services. For example, for a "demand"
system, an electronic control network such as described in the
previously cited U.S. Pat. No. 3,680,070 to Nystuen could be used
to selectively provide pressurized water to the nozzle 61. Control
over the duration of the impinging flow controls the amount of
detergent dispensed from surface 100a and ultimately the
concentration of detergent in the wash tank of the washing machine
(not shown).
Once pressurized fluid flow is applied to the nozzle 61, the nozzle
generates a pressurized spray pattern of pre-determined
configuration, which is uniformly directed across substantially the
entire upper exposed surface 100a of the solid detergent block 100,
as well as against any exposed surfaces of the solid detergent
ingredients 102 or 103 contained within the second
receptacle-shaped container 47. The spray pattern passes through
the mesh of the screen member 50 and impinges directly upon the
exposed surfaces of the retainably held solid detergent blocks,
dissolving by means of the hydraulic action of the spray itself, a
portion of the solid detergent blocks, at their respective exposed
surfaces. After striking the exposed surface 100a of the detergent
block 100, the spray (now converted into an aqueous liquid
detergent), drains or flows by gravity down the exposed surface
100a, dissolving by errosive action, further detergent at the
exposed upper surface 100a. (The inclination from the horizontal of
surface 100a facilitates gravity flow.) Upon reaching the
interconnecting wall portion 50c of the screen member 50, the
concentrated aqueous liquid detergent cascades over and through the
solid chlorine source or defoamer pellets or tablets 103 held
within the second receptacle-shaped container 47, to release a
predetermined proportionate amount of chlorine or defoamer
components therefrom--all of which passes (or drains) in solution
as concentrated detergent solution to the lower collector or
discharge aqueous liquid detergent solution does not accumulate in
region 30b but passes by gravity through the discharge port 34
(FIG. 8) within hose clamp extension 35 (FIGS. 8 and 9) into
appropriate conduit means or directly into an underlying wash tank
or ware-washing zone. Besides the errosive action of solution
passing from the upper exposed surface 100a of the detergent mass
100, the volume of solid ingredients within the second
.[.receptable-shaped .]. .Iadd.receptacle-shaped .Iaddend.container
47 is further directly dissolved by hydraulic action from the spray
projected from the nozzle 61.
This invention applies to dispenser configurations wherein the
nozzle 61 is mounted below the exposed detergent surface, and the
detergent surface is placed at an angle beyond 90.degree. (i.e.
rotated through 90.degree. up to 180.degree., which would be an
inverted position in which surface 100a faced downward). In the
embodiment of FIGS. 6-9, it is generally preferable to position the
nozzle 61 in a position overlying the solid detergent block to be
dissolved, and to place the exposed surface or surfaces of the
solid block detergent at an angle with respect to the hozizontal
(preferably between 10.degree. and 90.degree.), to supplement the
hydraulic dissolution with the errosive dissolution caused by the
solution flowing down the exposed surface(s). In a preferred
embodiment of the invention disclosed in the Figures, it has been
found that as inclination of the exposed detergent surface 100a of
approximately 60.degree. with the horizontal provides adequate
dwell time for the downwardly flowing water, while maintaining a
sufficiently small response time for the dispenser (i.e. that
elapsed time after which the pressurized spray is projected from
the nozzle 61 to the time in which the majority of the concentrated
detergent solution produced thereby has drained downwardly from the
discharge port 34).
The first lower wall 21c of the dispenser 21, as well as the upper
and lower peripheral side wall portions 44a and 42a of the
cartridge member 40 are inclined slightly with respect to the
horizontal (when the dispenser and enclosed cartridge member 40 are
mounted in operative position), to insure drainage of any liquid
solution (either the projected spray or resultant concentrated
solution) therefrom. Any liquid coming in contact with these
surfaces is directed toward the collector region 30b of the cavity
30.
Thus, the formation of an aqueous liquid detergent due to the flow
of liquid over surface 100a and/or pellets 103 is generally
simultaneous with the resulting downward or gravity flow, which
quickly reaches extension 35 and prevents standing water build-up.
Whenever the charge of solid detergent contained within the various
receptacles of the cartridge member 40 are depleted, the cartridge
is rapidly replaced by slidably removing the spent cartridge from
the inner cavity 30, through the access port 32, and simply
replacing the spent cartridge with a fully charged cartridge member
40. As previously discussed, the disposable cartridge could be
physically re-charged before replacement thereof into the housing
21. In such a re-usable cartridge application, it would be
desirable to wrap the highly caustic detergent block being placed
within the cartridge with a water soluble covering such as
polyvinyl-alcohol to protect the hands of the person handling the
solid detergent block used to charge the cartridge. Alternatively,
the cartridge member 40 could be replaced by an appropriate
retaining means forming an integral part of the housing 21 and
having appropriate receptacle retaining means for retainably
holding charges of solid block detergent in the required
pre-determined position with respect to the nozzle spray
pattern.
METHOD OF MANUFACTURING
Cast Detergent
While the following process is described with reference to specific
components, it should be understood that other components and
similar processes can be used to form a detergent solution which
can be cast into a mold and will solidify upon hydration of its
hydratable component. A particularly useful detergent composition
of this invention is formed by heating about 20-75 parts by weight
of a 40-75 weight percent aqueous solution of an alkali metal
hydroxide, e.g. sodium hydroxide, to a temperature above about
55.degree. C., preferably 65.degree.-85.degree. C. Temperatures
approaching 95.degree. C. can also be used; see Examples 9 and 9A
which follow. Which other alkali metal hydroxides may be used,
sodium hydroxide has been found to be particularly useful and the
following method of manufacturing will be described with respect to
it. Aqueous solutions of 50 weight percent sodium hydroxide are
readily commercially available. Solutions containing higher weight
percents of sodium hydroxide are also available (e.g. 73%) or can
be produced by adding a desired amount of anhydrous sodium
hydroxide to a 50 weight percent solution of sodium hydroxide. An
aqueous solution of sodium hydroxide can also be prepared by mixing
water and anhydrous sodium hydroxide in the desired ratio.
After the aqueous solution of sodium hydroxide reaches a
temperature above 55.degree. C., preferably above 65.degree. C.,
anhydrous sodium hydroxide can be added, as illustrated in several
of the Examples which follow, the prefered amount being about 8 to
about 40 parts by weight, i.e. about 8 to about 40% of the weight
of the total cast detergent composition. A lower temperture range
(e.g. 55.degree.-70.degree. C.) may also be used in the process,
e.g. during alkali metal condensed polyphosphate addition.
Typically, about 15 to about 40 parts by weight of anhydrous alkali
metal condensed polyphosphate are added to the solution. It is not
necessary to completely dissolve the alkali metal condensed
polyphosphate, since it can be suspended in the composition. After
the polyphosphate and/or optional fillers or components (the
polyphosphate is a preferred ingredient), are added, the mixture
can be cooled. Continuous mixing can be used during any dissolving.
Cooling, and thickening steps. The cooled and thickened mixture is
poured into a receptacle-shaped mold to a level at least part way
up the side molding surfaces. As the mixture continues to cool it
will solidify to form a cast composition. Solidification is
believed to be substantially due to to cooling. (This invention is
not bound by any theory, however.) After is has solidified, the
cast detergent is surrounded by and in contact with the mold on all
sides except for its upper surface which remains exposed.
After the base detergent has been poured into the mold, but before
it has solidified, preformed cores or plugs such as plug 6 in FIGS.
2 and 3 may be added. When a plug is added, the base detergent is
allowed to solidify around it and retain it in place. While any
shape or size plug could be used, it is normally preferred that the
plug extend to the entire depth of the base detergent as
illustrated in FIG. 2. The plug should extend the depth of the
solidified detergent so that a constant ratio of components can be
maintained while the base detergent and the plug are disolved
during use.
An alternative method of including a separately formed plug or
plugs could consist of using a mold comprising one or more smaller
molds positioned within the larger mold. The large mold would be
filled with the cast detergent base while the smaller mold or molds
would contain separate compositions such as a source of available
chlorine or a defoamer. The compositions could be cast into the
smaller mold or preformed as a plug and "pressed" into the mold.
The present invention will be further understood by reference to
the following specific Examples which are illustrative of the
composition, form and method of producing the solid, cast
detergent-containing article of this invention. It is to be
understood that many variations of composition, form and method of
producing the cast detergent would be apparent to those skilled in
the art. The following Examples, wherein parts and percentages are
by weight unless otherwise indicated, are only illustrative.
EXAMPLE 1
An 8.8 pound batch (approximately 4000 grams) of a solid cast
detergent of this invention was prepared using the following
procedure.
Fifty-five parts by weight of a 50 weight percent aqueous solution
of sodium hydroxide were added to a laboratory mixer provided with
a stirring means and a heating means. The 50% sodium hydroxide
solution was heated to approximately 55.degree.-60.degree. C. Nine
parts by weight of anhydrous sodium hydroxide were added to the
solution. The solution was stirred until the anhydrous sodium
hydroxide was completely dissolved. The addition of the anhydrous
sodium hydroxide had the effect of forming an approximate 57 weight
percent aqueous solution of sodium hydroxide.
Thirty-six parts of anhydrous sodium tripolyphosphate were added to
the solution and the solution was mixed. The tripolyphosphate did
not completely dissolve but was held in suspension by mixing.
Mixing was continued without heating until the solution began to
thicken, which was approximately 10-15 minutes after the addition
of the tripolyphosphate.
After the mixture had thickened but while it was still pourable,
six pounds (about 2700 grams) were poured into a receptacle-shaped
mold such as mold 3 in FIGS. 1-3, consisting of a slightly tapered
cylindrical plastic container measuring about 61/2 inches (about
16.5 cm) at the major diameter (the open end) and about 51/2 inches
(about 14 cm) at the minor diameter and about 41/2 inches (about
11.5 cm) in depth. The mixture was allowed to harden in the mold
which took approximately 5 minutes.
The composition of the final cast product (in weight-%) was
approximately:
______________________________________ 36.5% sodium hydroxide 27.5%
water 36.0% sodium tripolyphosphate 100.0%
______________________________________
While this product can be used as a detergent without additional
additives, additional components can be included as illustrated in
the following Examples.
EXAMPLE 2
A product with the same composition as that described in Example 1,
with the exception that 1 part by weight of the 50% sodium
hydroxide was replaced with 1 part by weight of a defoamer, was
produced. The defoamer was added following the addition of the
sodium tripolyphosphate and was kept uniformly dispersed by
continuous mixing until the mixture was poured in the mold. At the
time it was poured the mixture was sufficiently viscous so that a
uniform dispersion was maintained.
The composition of the final cast product (in weight-%) was
approximately:
______________________________________ 36% sodium hydroxide 27%
water 36% sodium tripolyphosphate 1% defoamer 100%
______________________________________
EXAMPLE 3
A mixture was prepared according to the procedure described in
Example 1. 53.57 parts of 50% sodium hydroxide, 8.77 parts of
anhydrous sodium hydroxide, and 35.06 parts of anhydrous sodium
tripolyphosphate were used. The mixture was then poured into the
mold described in Example 1. Before the mixture completely
solidified 2-6 parts of a preformed circular "plug" measuring about
1 inch in diameter (about 2.5 cm) and about 31/2 (about 9 cm) in
length, comprising a source of available chlorine, was placed
approximately in the center of the mold. The length of the plug was
such that it extended from the bottom of the mold to the surface of
the mixture. The mixture was then allowed to harden around the
plug.
Th composition of the solidified cast detergent (in weight-%)
was:
______________________________________ 35.5% sodium hydroxide 26.8%
water 36.1% sodium tripolyphosphate 2.6% chlorine plug 100.0%
______________________________________
The available chlorine containing plug was prepared by forming a
composition consisting of:
______________________________________ 59.7 parts calcium
hypochlorite - 65% available chlorine (HTH .TM. from
Olin-Mathieson) 14.4 parts Veegum .RTM. WG (from R. T. Vanderbitt
Company, Inc.) 25.9 parts dendritic sodium chloride 100.00
______________________________________
"Veegum" is a trademark for inorganic suspending agents.
After the three ingredients were mixed, plugs measuring about 1
inch (about 1 inch (about 2.5 cm) in diameter and about 31/2 inches
(about 9 cm) in length, were made by filling an appropriate size
cylindrical die with the composition and subjecting the die to
about 2,000 psi in a hydraulic press.
Plugs containing available chlorine were produced following the
same procedure from the two following compositions:
______________________________________ A. 100 parts Lithium
Hypochlorite 35% available chlorine B. 51.4 parts sodium
dichloroisocyanurate dihydrate 14.4 parts Veegum .RTM. WG 34.2
parts dendritic sodium chloride 100.0 parts total
______________________________________
Plugs produced from the these formulas were also found to perform
satisfactorily in the article of this invention.
EXAMPLE 4
This Example was designed to illustrate how plug 6 of FIGS. 2 and 3
could be further isolated from the base detergent. One plug was
made from each of the following formulas by compression molding at
about 2000 psi mold pressure.
______________________________________ 41.0 g (59.9%) calcium
hypochlorite - 65% available chlorine 10.0 g (14.3%) Veegum .RTM.
WG 18.0 g (25.8%) dendritic salt 69.9 g (100%) 41.5 g (59.7%)
sodium dichloroisocyanurate dihydrate 10.0 g (14.4%) Veegum .RTM.
WG 18.0 g (25.9%) dendritic salt 69.5 g (100%)
______________________________________
Both plugs were dipped in melted paraffin wax which was held at
just about its melting point of 56.5.degree. C. so that a very thin
coating of paraffin wax was formed on the sides and one end of the
plug. The wax allowed to cool and harden. The plugs were then
inserted into the cast detergent base of Example 2 following the
procedure of Example 3. No visual indication of any reaction at the
plug-detergent base interface was noted with either of these
plugs.
EXAMPLE 5
A mixture was prepared following the procedure described in Example
2. 52.57 parts of 50% sodium hydoxide, 8.77 parts of anhydrous
sodium hydroxide, 35.06 parts of anhydrous sodium tripolyphosphate
and 1 part defoamer were used. The mixture was then poured into the
mold described in Example 1. Before the mixture completely
solidified, 2.6 parts of a chlorine containing plug similar to
those described in Example 3 was added as described in Example
3.
The composition of the solidified cast detergent was:
______________________________________ 35.0% sodium hydroxide 26.3%
water 35.1% sodium tripolyphosphate 1.0% defoamer 2.6% chlorine
plug 100.0% ______________________________________
EXAMPLE 6
A solid cast detergent of the same formula as that described in
Example 5 was produced. However, instead of mixing the defoamer
with the base detergent is was added in the form of a plug. Thus,
two plugs were used, one comprising a defoamer and the other
comprising a source of available chlorine. The two plugs were
placed near the center of the mold after the detergent was added,
but before it solidified.
The composition of the solidified cast detergent was:
______________________________________ 35.0% sodium hydroxide 26.3%
water 35.1% sodium tripolyphosphate 1.0% defoamer plug 2.6%
chlorine plug 100.0% ______________________________________
The defoamer plug was prepared by heating together 60 parts of a
viscous (at room temperature) polyoxyalkylene glycol and 40 parts
of a solid mixture of mono-and di-alkyl phosphate esters until the
phosphate esters melted and then mixing until the mixture was
uniform. The solution was then poured into a cylindrical mold and
allowed to cool and form a solid plug at room temperature.
Similar plugs were produced following essentially the same
procedure using: 50 parts of a polyethylene glycol, 25 parts of a
polyoxyalkylene glycol, and 25 parts of a mixture of mono- and
di-alkyl phosphate esters.
EXAMPLE 7
A solid cast detergent was produced using the same formula and
procedure as described in Example 2 except that the 1 part of
defoamer was added as a plug similar to those described in Example
6.
EXAMPLE 8
Approximately 6 pounds of a solid cast detergent of the invention
were prepared using the following procedure. 40 parts of anhydrous
sodium metasilicate and 39 parts of a 10 weight percent aqueous
solution of sodium hypochlorite were added to a laboratory mixer
provided with a stirring means and a heating means. The solution
was heated to approximately 55.degree.-60.degree. C. Twenty parts
of anhydrous sodium tripolyphosphate were added to the solution and
the solution mixed without heating until it began to thicken. After
the mixture had thickened but while it was still pourable it was
poured into a mold consisting of the dimensions described in
Example 1. Before the mixture completely solidified, 1 part of a
defoamer plug similar to those described in Example 6 was added
following the previously described procedure.
The composition of the solidified cast detergent was
approximately:
______________________________________ 40% sodium metasilicate 35%
water 20% sodium tripolyphosphate 4% sodium hypochlorite 1%
defoamer plug 100% ______________________________________
EXAMPLE 9
This Example was designed to illustrate that the sodium
tripolyphosphate component of the previous Examples can be formed
in-situ by reating sodium trimetaphosphate with sodium hydroxide
via the following reaction: ##STR2##
Approximately 2200 ml of 50% aqueous sodium hydroxide was added to
a stainless steel, jacketed beaker equipped with a "Lightning"
stirrer. Following the addition the temperature was 70.degree. F.
(21.degree. C). Next 1440 g of powdered trimetaphosphate was added
slowly. As the temperature of the mixture approached 100.degree. F.
(38.degree. C.), cooling was applied. The remainder of the
trimetaphosphate was added incrementally until the entire 1440
grams has been added. During the addition a maximum temperature pf
200.degree. F. (93.degree. C.) was reached.
Upon sitting for several minutes the mixture formed a solid which
could have been cast into a mold and used as the solid, cast
detergent of this invention.
EXAMPLE 9A
This Example illustrates that chlorinated trisodium phosphate may
be used as the chlorine source. A solid cast detergent having the
following composition was prepared:
______________________________________ 36.0% caustic soda 27.0%
water 36.0% sodium tripolyphosphate 1.0% defoamer 100.0%
______________________________________
The above mixture was prepared using the procedure as described for
Example 2. The mixture was poured (about 2360 g) into the mold
which has a removable 2 inch diameter cylinder placed in the
center. After the mixture had solidified, the 2 inch diameter
cylinder was removed leaving a hollow cylindrical cavity. This
hollow cavity was filled with about 340 grams of molten chlorinated
trisodium phosphate. The chlorinated trisodium phosphate solidified
upon cooling below its melting point. Some reaction occurred at the
interface of the plug. It is believed that this reaction may be
reduced significantly allowing the cast detergent to cool
thoroughly before the chlorinated trisodium phosphate was poured
and/or coating the cavity surface with an inert barrier such as,
for example, paraffin wax or mixed mono and dialkyl esters of
polyphosphoric acid or like materials.
EXAMPLE 10
This Example was designed to illustrate the production of a
non-phosphate solid, cast detergent. Forty parts of 50% aqueous
sodium hydroxide was heated to 150.degree. F. (65.5.degree. C.) in
a jacketed stainless steel beaker equipped with a stirrer. Twenty
parts of anhydrous sodium hydroxide were added and the mixture was
stirred until a molten solution was formed. Twenty-five parts of
liquid silicate (RU silicate from Philadelphia Quartz) having an
SiO.sub.2 /Na.sub.2 O ratio of 2.54 was added and resulted in the
temperature of the mixture increasing to about 200.degree. F.
(93.degree. C.). The mixture was cooled to about 150.degree. F.
(65.degree. C.) and 15 parts of sodium polyacrylate were added
slowly while stirring continued.
The mixture was poured into a plastic container where it solidified
upon cooling.
EXAMPLE 11
The purpose of this Example is to compare the consistency of
available chlorine recovery from a cast detergent-containing
article produced according to the instant invention and a
conventional, prior art, powdered detergent. The prior art formula
used consisted of a mixture of sodium tripolyphosphate, sodium
dichloroisocyanurate (a chlorine source). Sodium metasilicate, and
sodium hydroxide. Sodium dichloroisocyanurate comprised
approximately 2.8% of the formula. The cast detergent-containing
article used was produced by the process and using the formula
described in Example 5. The chlorine source was present in the form
of a plug situated approximately in the center of the cast base
detergent. The cast detergent containing article was dispensed from
an apparatus similar to the one illustrated in FIG. 4. The prior
art formula was dispensed from a water-in-reservoir dispenser of
the type illustrated in FIG. 1 of U.S. Pat. No. 3,680,070, issued
July 25, 1972 (Nystuen).
Samples of the effluent from the dispensers were collected
periodically and titrated for alkalinity to the phenolphthalein end
point with hydrochloric acid and titrated for available chlorine
with sodium thiosulfate using the conventional iodometric
titration. The influent water temperature to both dispensers was
about 71.degree. C. (160.degree. F.).
The amount of detergent present in the effluent was determined by
the alkalinity of the effluent. The "Chlorine recovered-percent of
theoretical" (CRPT) was then calculated from the formula: ##EQU1##
The results are illustrated in FIG. 5. FIG. 5 shows that the solid
cast detergent of this invention provides very uniform chlorine
recovery when compared to a prior art formulation. It is theorized
that the differential solubility of the components of the prior art
powdered detergent is responsible for the more erratic chlorine
recovery shown by the prior art detergent.
EXAMPLE 12
This Example was designed to determine the effect of segregation
during the manufacture of a conventional, prior art, powdered
detergent. Since there should be no segregation with the solid cast
detergent of this invention, (since all the components are
physically locked in place) any significant segregation with a
powdered detergent would represent a disadvantage of the powdered
detergent.
The conventional powdered detergent used was the same as that
described in Example 11. This powdered detergent is commonly
packaged in two-pound packages. Seven two-pound packages from the
same production batch were selected at random for analysis. Ideally
each of the packages should contain the same percentage of each of
the four ingredients.
The contents of each of the packages were weighed and the entire
contents dissolved in an appropriate quantity of water in a 30
gallon drum to give a 1% weight/volume solution. This eliminated
any variation due to the possibility of different amounts of
detergent being present in different packages. A 100 ml sample was
withdrawn from each drum and titrated for available chlorine with
sodium thiosulfate using the standard iodometric titration. The
results were as follows:
______________________________________ Sample No. Percent Available
Chlorine ______________________________________ 1 1.63 2 2.00 3
1.53 4 1.56 5 1.54 6 1.96 7 1.65
______________________________________
As indicated, the percentage of available chlorine varied from 1.53
to 2.00. This variation is in part due to segregation during mixing
and packaging of the powdered detergent. This segregation is
probably one factor leading to the variation in chlorine delivery
illustrated in FIG. 5.
EXAMPLE 13
This Example was designed to compare the chlorine stability of cast
detergents of this invention containing a chlorine source directly
in the base detergent with cast detergents of this invention which
incorporate a chlorine source as a core or plug, such as those
described in Exampe 3. Three different chlorine sources were used:
sodium dichloroisocyanurate dihydrate (NaDCC2H.sub.2 O), lithium
hypochlorite (LiOCl), and calcium hypochlorite (Ca[OCl].sub.2). All
of the compositions were produced following the procedure of
Example 1 with the chlorine source being added directly to the
mixture following the addition of the sodium tripolyphosphate in
one case and the chlorine being added as a plug in the other. In
the third case the chlorine source plug was dipped in a paraffin
wax (m.p. 52.5.degree. F.) and in a fourth case the chlorine source
plug was dipped in mono and dialkyl ester of polyphosphoric acid, a
wax-like solid (m.p. 150.degree.-160.degree. F.). The formula used
and the available chlorine remaining after various storage times at
room temperature are shown in Table I.
As indicated by Table I, when the chlorine source is added directly
as a component of the cast detergent most of the chlorine is lost
within 24 hours. .[.However, when the chlorine source is added
directly as a component of the cast detergent most of the chlorine
is lost within 24 hours..]. However, when the chlorine source is
incorporated into the cast detergent as a preformed core or plug,
excellent chlorine stability results with Ca(OCl).sub.2 and lithium
hypochlorite but not with NaDCC2H.sub.2 O. When the chlorine source
plug was coated with a film of paraffin wax or a waxy mono and
dialkyl ester of polyphosphoric acid the best stabilities were
obtained.
TABLE I
__________________________________________________________________________
CHLORINE STABILITY Components* Ca(OCl).sub.2 LiOCl NaDCC--2H.sub.2
O Ca(OCl).sub.2 LiOCl NaDCC--2H.sub.2 O
__________________________________________________________________________
CHLORINE SOURCE ADDED DIRECTLY TO DETERGENT CHLORINE SOURCE ADDED
AS PLUG NaOH - 50% 52.4 51.0 52.2 52.57 52.57 52.57 NaOH Anhyd 9.0
9.0 9.0 8.77 8.77 8.77 STP 36.0 36.0 36.0 35.06 35.06 35.06
Defoamer 1.0 1.0 1.0 1.00 1.00 1.00 Ca(OCl).sub.2 1.6 -- -- 2.60 --
-- NaDCC--2H.sub.2 O -- -- 1.8 -- -- 2.60 Li(OCl) - 35% -- 3.0 --
-- 3.33 -- Percent Available 3.5 17.4 3.5 -- -- -- Chlorine
remaining after 24 hours Percent Available -- -- -- -- -- --
Chlorine remaining after 2 days Percent Available -- -- -- -- 60
1.5 Chlorine remaining after 15 days Percent Available -- -- -- 98
-- -- Chlorine remaining after 29 days CHLORINE SOURCE ADDED AS
PLUG CHLORINE SOURCE ADDED AS PLUG BUT COATED WITH PARAFFIN BUT
COATED WITH PE-053 NaOH - 50% 52.57 52.57 52.57 52.57 52.57 52.57
NaOH Anhyd 8.77 8.77 8.77 8.77 8.77 8.77 STP 35.06 35.06 35.06
35.06 35.06 35.06 Defoamer 1.00 1.00 1.00 1.00 1.00 1.00
CA(OCl).sub.2 2.60 -- -- 2.60 -- -- NaDCC--2H.sub.2 O -- -- 2.60 --
-- 2.60 Li(OCl) - 35% -- 3.33 -- -- 3.33 -- Percent Available -- --
-- -- -- -- Chlorine remaining after 24 hours Percent Available --
-- -- -- -- -- Chlorine remaining after 29 days Percent Available
100 99 100 -- -- -- Chlorine remaining after 15 days Percent
Available -- -- -- 100 99 100 Chlorine remianing after 2 days
__________________________________________________________________________
*Components shown in parts by weight. These products essentially
same as Product of Example 5.
EXAMPLE 14
The purpose of this Example was to compare the uniformity of
delivery of defoamer from: (A) a conventional powdered detergent
(Score.TM., a commerical product of Economics Laboratory, Inc.);
(B) a cast detergent (product of Example 5); and (C) a cast
detergent incorporating the defoamer as a core or plug (product of
Example 6). All three of the formulations contained 1% by weight of
defoamer. The (A) conventional detergent and (B) the product of
Example 5 contained the same defoamer; (C) the product of Example 6
contained the blend of two defoamers described in Example 6 (the
blend was used to obtain a solid product which could be molded into
a plug).
All tests were conducted in a Hobart C-44 (trademark) single tank
dishwashing machine. A C-11 Dispenser (trademark of Economics
Laboratory, Inc.), a water-in-reservoir type dispenser, was used to
dispense product (A) (the conventional powdered detergent). The
Hobart C-44 (trademark) machine was equipped with a dispenser
simular to that illustrated in FIG. 4 for dispensing the solid cast
detergent products (B) (product of Example 5) and (C) (product of
Example 6). Both dispensers were contolled by a conductivity base
controller of the type described in U.S. Pat. No. 3,680,070, issued
July 25, 1972 (Nystuen). The controller was set to maintain a 0.2%
concentration of detergent in the wash tank. The water temperature
was about 140.degree. F. (65.degree. C.) for all of the tests.
Defoamers are included in detergents for spray-wash machines to
control foam created by food soils. Foam in a wash tank leads to
entrapment of air in the wash solution being recirculated through
the machine and results in a reduction in mass and kinetic energy
which leads to poor soil removal. Excess foam in a wash tank causes
a loss in water pressure which can be measured by a manometer
connected to the wash manifold upstream from the water pump. Egg is
a common foam-causing food soil and was selected for use in this
test.
The C-11 Dispenser optimally holds about four pounds of powdered
detergent and thus four pounds of conventional detergent (A) were
used in the test. Products (B) and (C) were approximately six
pounds each and were of the configuration described in Example 1
and illustrated in FIGS. 1-4.
The pressure (in inches of water) was recorded when the dispenser
was freshly charged, when about one-half of the detergent had been
dispensed, and when about four-fifths of the detergent had been
dispensed. Manometer readings were taken on the freshly charged
detergent: (1) with water alone, (2) after the detergent was added,
(3) five minutes after 115 grams of egg were added, and (4) five
minutes after an additional 100 grams of egg were added.
Between the "Freshly Charged" test and the "Detergent 1/2 Spent"
test, the fill valve was opened to deliver 2 gallons of water per
minute for dilution to simulate normal dilution of the wash tank by
rinse water which is diverted to the wash tank to freshen the wash
water. The conductivity controller dispensed detergent as required
to maintain a 0.2% concentration of detergent in the wash tank.
When about one-half of the detergent originally in the dispensers
was left, manometer readings were taken and the two egg additions
described above repeataed with readings being taken five minutes
after each addition. The same procedure was repeated after about
one-fifth of the detergent originally present was left in the
dispensers (four-fifths spent).
The "Detergent 1/2 Spent" test was somewhat more severe than the
"Freshly Charged" test and, likewise, the "Detergent 4/5 Spent"
test was somewhat more severe than the "Detergent 1/2 Spent" test,
due to the cumulative concentration of egg soil resulting because
the wash tank was not drained between tests.
The results of these tests are summarized in Table II.
TABLE II
__________________________________________________________________________
FRESHLY CHARGED DETERGENT 1/2 SPENT DETERGENT 4/5 SPENT Wash
Pressure % Wash Pressure % Wash Pressure % (inches of water) Loss
(inches of water) Loss (inches of water) Loss
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(A) Conventional Powdered Detergent Water alone: 43 -- -- -- -- --
Detergent added: 43 -- 42.5 -- 41.0 5.0 5 minutes after 115 g. 38
12 26.0 40 25.0 42 egg added: 5 minutes after additional 28 35 22.0
48 * -- 100 g. egg added: (B) Defoamer in Cast Detergent (Product
of Example 5) Water added: 42 -- -- -- -- -- Detergent added: 42 --
43 -- 42.5 -- 5 minutes after 115 g. 42 0 43 0 41.0 3.0 egg added:
5 minutes after additional: 42 0 30 30 29.0 32 100 g. egg added (C)
Defoamer as Plug in Cast Detergent (Product of Example 6) Water
alone: 42.5 -- -- -- -- -- Detergent added: 42.5 -- 42 -- 42.5 -- 5
minutes after 115 g. 42.5 0 42 0 41.0 0 egg added: 5 minutes after
additional 42.5 0 42 0 41.0 3.5 100 g. egg added:
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*Test was stopped due to excessive foam to avoid damage to pump and
motor
The data in Table II indicates that Product (C) (the product of
Example 6 with the defoamer included as a plug) had the highest and
most consistent wash pressures and that Product (B) (the product of
Example 5 with the defoamer included in the cast detergent) had
higher and more consistent wash pressures than Product (A) (the
conventional powdered detergent). The higher and more consistent
wash pressures indicate more uniform defoamer delivery.
It was noted that the defoamer incorporated in the powdered
detergent (A) floated to the top and formed an oily film in the
water-in-reservoir dispenser. It is believed that this resulted in
slug-feeding of the defoamer instead of uniform delivery. In
contrast, with the solid cast detergent of this invention, both the
detergent and defoamer are dispensed simultaneously which helps
assure uniform dispensing of the defoamer.
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