Note: Descriptions are shown in the official language in which they were submitted.
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CLEANSING ARTICLES WITH CONTROLLED DETERGENT RELEASE
AND METHOD FOR THEIR MANUFACTURE
The present invention relates to cleansing and scouring articles comprising a
porous pad which includes a controlled detergent release composition and to a
method for the manufacture of such articles including the preparation of a
coatable
polymer/detergent blend and the application of such a blend to a porous pad.
to Scouring and cleansing articles, e.g., for home cleaning applications are
well
known. Commercially available articles are often sold with soap or detergent
incorporated within the article. Solid soap and detergent compositions are
commonly incorporated within steel wool and other common cleansing and
scouring articles. Although soaps possess the desirable properties of being
slow to
15 dissolve in water and having a sustained presence within the articles over
a period
of extended use, soaps typically lack one or more of the properties of good
foaming, good detergency and good grease cutting ability. Moreover, the
processing and manufacture of these soap containing articles requires the
undesirable use of heat and/or solvents in order to adequately blend the raw
2o materials as well as to incorporate the blended soap compositions into the
cleansing
article.
In order to overcome these shortcomings in the use of soaps, synthetic
detergents have been used in at least some commercial scouring articles
primarily
because of their improved grease cutting ability and superior foaming ability.
25 Detergents, however, are readily soluble in water and this solubility has
contributed
to the shortened useful life for scouring articles containing such detergents.
In
general, cleansing or scouring articles treated with detergents tend to lose
their
detergent loadings after only a few short uses or even after a single extended
use.
In light of the foregoing, it would be desirable to provide a cleansing
article with a
3o good grease cutting detergent that will dissolve readily in water but will
release
slowly from the article over an extended period of time and over a number of
uses.
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Scouring and cleansing articles made from steel wool are also well known.
Commercially available steel wool pads include the aforementioned soaps and,
consequently have exhibited the above discussed problems of poor foaming,
detergency and grease cutting ability. Additionally, steel wool articles tend
to rust
when exposed to moisture, and the steel fibers of the pad have sharp ends
which can
penetrate the skin on the hand of the user. Accordingly, it is also desirable
to
provide the aforementioned improved detergent in a form which will release in
a
controlled manner after exposure to moisture and which is provided on a porous
pad which will not rust or exhibit other undesirable characteristics of steel
wool.
~o Past attempts to extend the useful life of the soap or detergent within
such
scouring or cleansing articles have had only limited success. These attempts
have
varied in their approaches but have included, for example, encapsulating the
soap
within a pouch-Iike portion of the article or by blending the soap or
detergent with
insoluble polymers or with binders such as cellulose and derivatives thereof.
These
attempts have generally been less than satisfactory for several reasons.
Encapsulation of the soap within the article r equires a high loading of the
soap,
thereby increasing the cost to manufacture the article while also retaining
the
aforementioned shortcomings of soaps in general. The use of binders has either
failed to significantly extend the useful life of the detergent or has made
the
2o detergent less available because ef the nature of the binder material
employed.
-2-
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60.557-5520
< EP-A-0 153 146 relates to an article suitable for wiping
surfaces including a substrate which can carry the detergent
that is delivered to the surface during wiping.
GB-A-1 522 759 relates to surface-active agent- and
detergent-containing compositions comprising a crosslinked,
water- and solvent insoluble polymeric network and a
surface-active agent entrapped within said network.
US-A-4 126 563 describes a composition for treating fabric
to impart desired properties thereto comprising a water
soluble film forming adhesive and at least one adjuvant.
JP-A-2 047 397 relates to paper containing soap in its fiber
tissues.
US-A-4 014 808 describes a detergent formulation useful in
aqueous working solution for the treatment of soiled floor
surfaces.
US-A-4 421 526 relates to polyurethane foam cleaning pads
having abrasive or detergent dispersed within the cellular
structure of the pad.
US-A-5 238 587 relates to a laundry-cleaning sheet
comprising a gelled solvent-based dry-cleaning composition.
EP-A-0 211 664 relates to an abrasive article suitable for
cleaning surfaces without scratching. >
-2a-
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60.557-5520
Accordingly, there is a long felt and unfulfilled need in the art to provide a
scouring or other cleansing article which includes a controlled detergent
release
composition and to provide a method for the manufacture thereof. There is also
a
need to provide such a controlled detergent release article having a pad
constructed
of a material which will not oxidize after exposure to water and which can
withstand a number of uses without depleting its detergent loading. It would
be
especially desirable to provide in such an article a slow or controlled
detergent
release composition which renders the detergent readily available for its
intended
cleansing function, providing excellent detergency and foaming over an
improved
1o useful life for the article.
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Brief Description of the Invention
The present invention provides a controlled
detergent release composition and a scouring or cleansing
article including such a controlled detergent release
composition, the article being generally useful, for
example, in home cleaning applications. The cleansing
article of the invention exhibits improved properties when
compared with articles in the prior art, including enhanced
detergency and grease cutting properties over an extended
useful life.
According to one aspect of the present invention,
there is provided a cleansing article comprising: a porous
pad; and a water soluble, water swellable controlled
detergent release composition incorporated within said pad,
said composition comprising polyacrylamide having detergent
blended therein to provide a weight ratio of polymer
solids: detergent solids between about 1:9 and about 1:100
and, said polyacrylamide having a weight average molecular
weight of at least 1 million, said polyacrylamide and said
detergent blended within said composition to allow for the
controlled release of said detergent when said composition
is exposed to water.
According to another aspect of the present
invention, there is provided a cleansing article, comprising:
a pad comprising a lofty nonwoven, open, three-dimensional
network of fibers; and a water soluble, water swellable
controlled detergent release composition coated on said
fibers, said composition comprising a polyacrylamide having
a detergent therein to provide a weight ratio of polymer
solids: detergent solids between about 1:9 and about 1:100
and, said polyacrylamide having a weight average molecular
weight within the range from about 1 million to about
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60.557-5520
15 million, wherein said polyacrylamide and said detergent
are blended within said composition to allow for controlled
release of said detergent when said composition is exposed
to water.
According to yet another aspect of the present
invention, there is provided a process for manufacture of a
cleansing article, the process comprising: preparing a water
soluble, water swellable, coatable composition comprising
polyacrylamide having a weight average molecular weight of
at least 1 million, detergent and a liquid vehicle, to
provide a weight ratio of polymer solids: detergent solids
between about 1:9 and about 1:100 and, said coatable
composition on drying forms a controlled detergent release
composition to allow for controlled release of said
detergent when said composition is exposed to water;
applying said coatable composition to a porous pad; and
drying said coatable composition to provide said controlled
detergent release composition within said porous pad.
-3a-
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60.557-5520
In one aspect of the invention, the cleansing article comprises a porous pad
and a controlled detergent release composition incorporated within said pad
comprising poiyacrylamide having detergent blended therein. The polyacrylamide
provides a polymeric matrix within the composition to temporarily retain the
detergent within the article and to slowly release it during use.
In describing the articles and the controlled detergent release composition of
the invention, certain terms will be understood to have the specific meanings
set
forth herein. "Controlled detergent release composition" refers to a
composition
comprising polyacrylamide with detergent blended therein, which may be
to incorporated within a porous pad or other substrate to release its loading
of
detergent over a period of time when the article is exposed to water or
another
solvent at a release rate which is slower than the release rate for the same
type of
article which includes the same porous pad and the same detergent loading but
with
no polymer. "Cleansing article" refers to any article useful for any cleaning
application which includes a porous pad, poiyacrylamide and detergent
according to
the invention including but not limited to home, industrial, agricultural,
veterinary,
automotive, office or other applications. "Porous pad" refers to any substrate
which has at least one opening into which the controlled detergent release
composition may be inserted, incorporated or otherwise deployed within, it
being
2o understood that at least a portion of such composition may be deployed on
the
exterior surface of such substrate so long as it is available for controlled
detergent
release as the pad is being used in its intended environment (e.g., usually an
aqueous
environment). "Polymer/detergent blend" refers to a coatable composition
comprising poiyacrylamide, detergent and a liquid vehicle (e.g., water) which
can be
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applied to a porous pad or other substrate and which on drying forms a
controlled
detergent release composition.
The polyacrylamide is preferably blended with detergent to provide a weight
ratio of polymer solids:detergent solids between about 1:9 and about 1:100 and
more preferably between about 1:12 and about 1:30. The detergent may be
prepared from one or more anionic, cationic, amphoteric and nonionic
surfactants
and, the preferred polyacrylamide is preferably a high molecular weight
polymer
having a weight average molecular weight greater than 200,000. More
preferably,
the weight average molecular weight of the polyacrylamide is at least about
l0 1,000,000 and most preferably between about 1,000,000 and about 15,000,000.
The invention also provides a method for the manufacture of the foregoing
articles comprising preparing a coatable polymer/detergent blend comprising
polyacrylamide, detergent and a liquid vehicle which on drying forms a
controlled
detergent release composition applying said coatable blend to a porous pad,
and
drying said blend to provide said controlled detergent release composition.
The
controlled detergent release composition is substantially retained within the
pad for
subsequent use and thereafter slowly released when used.
Still another aspect of the invention provides a controlled detergent release
composition, comprising polyacrylamide including detergent blended therein.
2o As is set forth below, the articles of the invention are preferably
provided as
nonwoven scouring pads made of a multiplicity of thermoplastic organic fibers
which are bonded together by any number of known techniques, forming an open
lofty array of fibers which are coated with the controlled detergent release
composition. Articles of the invention exhibit improved detergent retention as
well
as improved detergency and foaming, as demonstrated in the test results set
forth
below.
In the present invention, the incorporation of an effective amount of
detergent within a water soluble, water swellable, polymer matrix consisting
of a
polyacrylamide polymer of a sufficiently high molecular weight will achieve
the
3o desirable effect of providing a controlled detergent release composition
effective in
the aforementioned porous pads. A polyacrylamide having a weight average
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molecular weight greater than 200,000 will adhere to the fibers of the pad to
provide a matrix which swells when wet, and which will release an effective
amount
of detergent during a cleaning application. Surprisingly, it has been found
that the
controlled detergent release composition provides unexpected improved
detergency
and foaming when compared with a similar scouring article treated with an
equivalent loading of detergent but excluding the polyacrylamide polymer.
Those skilled in the art will more fully understand the details of the present
invention upon further consideration of the remainder of the disclosure
including the
detailed description of the preferred embodiment and the appended claims.
l0 The controlled detergent release composition of the invention comprises a
water soluble and water swellable polyacrylamide polymer with a detergent
blended
therein. The composition is water soluble and may be prepared as an aqueous
polymer/detergent blend and thereafter coated over a porous pad or other
substrate.
The preparation and the application of the blend is preferably carried out at
room
15 temperature, although it is desirable to apply heat to dry the applied
blend within
the article.
The preferred polyacrylamide polymer is of a sufl-iciently high molecular
weight so that the polymer will remain adhered within the porous pad during
use,
swelling when moistened but dissolving only gradually with each use. The
polymer
2o releases an effective amount of detergent during each use of the cleansing
article.
Preferred polyacrylamides suitable for use in the invention are those which
when blended with detergent provide a viscous coatable composition which will
contain the detergent adherently within the porous pad and, when in use, swell
and
slowly dissolve to controllably release incremental useful amounts of its
detergent
25 loading. Such polyacrylamides are commercially available as free flowing
solid
powders that can be dispersed and dissolved in either hot or cold water. More
preferably, the polyacrylamide is a homopolymer of acrylamide which is
essentially
nonionic and which has an average molecular weight (weight average) exceeding
200,000 and, due to present commercial availability, more preferably has a
3o molecular weight of at least about 1,000,000 and most preferably between
about
1,000,000 and about 15,000,000. After incorporation into a polymer/detergent
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blend, the polyacrylamide can be crosslinked in a known manner. Preferably,
however, the polyacrylamide is not crosslinked because it has been found that
a
polyacrylamide which is not crosslinked will perform better than a crosslinked
polyacrylamide after incorporation into a porous pad. Commercially available
polyacrylamide polymers suitable for use in the present invention include
those
available under the trade designations "Cyanamer N-300 LMW ' available from
American Cyanamid Corporation of West Patterson, New Jersey; and
polyacrylamide cat. # 18, 127-7 available from Aldrich Chemical Corp. of
Milwaukee, Wisconsin. It will be understood that the invention is not limited
to any
to one of the specific foregoing polyacrylamide polymers, and those skilled in
the art
will appreciate that other commercial polyacrylamide polymers and polymer
blends
may be used in the controlled detergent release compositions described herein.
It is
contemplated that any and all high molecular weight (e.g. greater than
200,000)
polyacrylamideJdetergent blends incorporated within a scouring pad or other
15 substrate to provide a controlled release of detergent in a cleaning
application fall
within the broad teachings of the present invention.
As mentioned above, the polyacrylamide polymer is blended with a
detergent to provide a polymer/detergent blend which can then be applied to a
substrate such as a porous pad. It is contemplated that the detergents useful
in the
2o present invention are those which will readily dissolve in water and which
provide
excellent sudsing, cleaning and grease cutting properties in normal home
cleaning
applications. These properties are obtained in the finished scouring article
by
blending the detergent within the water soluble polyacrylamide polymer,
thereby
preserving the availability of the detergent over an extended period of time.
25 Surprisingly, the incorporation of detergent within a high molecular weight
polyacrylamide polymer has been found to enhance detergency when articles of
the
present invention are compared with similar cleansing articles which do not
include
a water swellable polyacrylamide polymer. The detergent used in articles of
the
invention may include one or more anionic, cationic, nonionic and amphoteric
3o surfactants as well as combinations of such surfactants. It is desired that
the
detergent is mild on the skin of the user, is non-toxic and remains in the
liquid state
CA 02205428 2006-03-02
60557-5520
at room temperature. It is preferred that in blends of one or more anionic,
nonionic,
cationic and/or amphoteric surfactants, a higher concentration of anionic
surfactants
is desired for enhanced foaming and detergency.
Anionic surfactants function as the primary surfactant in the controlled
detergent release compositions of the invention, imparting detergency to the
composition. Anionic surfactants are preferably added to the polymer/detergent
blend at concentrations ranging between about 5% and about 60% by weight of
the
dry solids. Anionic surfactants suitable for use herein include sodium or
ammonium
salts of sulfonated al)'yls, sulfonic acids, sulfated alkyl ethers, sulfated
fatty esters
1o and lauryl sulfates. Alkyl sulfates such as sodium lauryl sulfate and
ammonium
iauryl sulfate can be included within the detergent formulations of the
invention.
Exemplary of suitable commercially available sodium iauryl sulfates are those
available under the trade designations "Rhodapon LS" from Rhone Poulenc of
Cranbury, New Jersey and "Sulfocherii SLS" from Chemron Corp. of Paso Robles,
15 California. Exemplary commercial ammonium lauryl sulfates include "Rhodapon
L-
22" from Rhone Poulenc and "SulfochemMALS" from Chemron Corp. Alkyl ether
sulfates such as sodium lauryl ether sulfate are useful in the present
invention and
include those available under the trade designations "Rhodapex ES" from Rhone
Poulenc; "Sulfochem ES-70" from Chemron Corp.; and "Witcolate ES-3" from
2o Witco Corp. of Connecticut. Suitable sulfonates include sodium
dodecylbenzene
TM
sulfonate available commercially under the trade designations "Rhodacal DDB-
40"
from Rhone Poulenc; "Witcolate 1240" (slurry) from Witco Corp.; and "BiosoftMD-
40" from Minnesota Solvents of Minneapolis, Minnesota.
Amphoteric surfactants are mild secondary foaming agents imparting
25 additional detergency as well as enhancing the blend's mildness on the
skin. As a
secondary foaming agent, amphoteric surfactants may be present at weight
percentages ranging from about 1 % to about 20% of the dry solids. Exemplary
of
amphoteric surfactants suitable for use in the invention include
cocamidopropyl
betaines such as those available commercially under the trade designations:
TM
30 "Mirataine CB" from Rhone Poulenc of Cranbury, New 3ersey. Another suitable
amphoteric detergent is Coco/oleoamidopropyl betaine available commercially
CA 02205428 2006-03-02
~0557~-5520
TM TM
under the trade designations: "Miranol COB" from Rhone Poulenc; "Chembetaine"
TM
from Chemron Corporation of Paso Robles, California; and "Emcol COB" from
Witco Corporation of Connecticut.
Nonionic surfactants may be included in the polymer/detergent blends of the
invention as low foaming surfactants used for viscosity building or as medium
foaming surfactants used for foam boosting. Preferably, nonionic surfactants
included in the invention are those which will not cause gelling or other
modifications of the polymer/detergent blend which could interfere with room
temperature coating of the blend on to the substrate. The nonionic surfactants
may
1o be present at weight percentages of the polymeridetergent blend between
about 1%
and about 5% of the dry solids. Among nonionic surfactants and foam
stabilizers
suitable for inclusion herein are monoethanolamides such as cocamide MEA,
available commercially under the trade designation "AlkamideMC212" from Rhone
TM
Poulenc; and, "Amidex ME" from Chemron Core. Diethanolamides such as
15 coconut diethanolamide is suitable for use herein and is commercially
available
fM
under the trade designation "Standamid SD" from Henkel Corp. of Ambler,
Pennsylvania. Various other ethoxylated amines and amides along with fatty
alkanolamides can be included as are known to those skilled in the art.
Cationic surfactants can be included within the polymer/detergent blend,
20 preferably at weight percentages of the dry solids between about 1% and
about
20% to act as an emulsion stabilizer and/or a viscosity builder. Amine oxides
are
the commonly used cationic surfactants such as lauramine oxide available under
the
trade designation "Rhodamox L" from Rhone Poulenc and "Chemoxide LM-30"
from Chemron Corporation; lauramidopropylamine oxide available as "RhodamoxTM
25 LO" from Rhone Poulenc; and, stearamide oxide available as "ChemoxideMST"
from
Chemron Corporation.
It is contemplated that other surfactants and blends thereof can be included
in the detergent in formulating the polymer/detergent blends of the present
invention. The invention is not to be limited in any way by the particular
detergent
3o formulation included within the polymer/detergent blends described herein
and the
foregoing discussion of specific surfactants and concentration ranges therefor
_g_
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should be understood to be exemplary and not limiting in any way. The
formulation
of a detergent blend is believed to be within the expertise of those skilled
in the art,
and any detergent included within a polymer/detergent blend in a manner
consistent
with the teachings of the present disclosure is to be construed as within the
scope of
the invention.
As mentioned, the polymerldetergent blends of the invention incorporate
therein a detergent formulated from one or more of the above described
surfactants
blended with a suitable polyacrylamide polymer to provide a polymer/detergent
blend which may be coated on a scouring pad or other substrate. The preferred
1o polymer/detergent blends are those which can be blended at room temperature
and,
when applied to the substrate and dried, provide a water swellable controlled
detergent release composition which slowly releases detergent when wet. More
preferred are those water swellable compositions which dissolve very slowly
over
time and which are capable of remaining affixed to the scouring article over a
15 number of uses. Such compositions will remain on the fibers of the scouring
article
after a single cleaning application and will re-dry thereon and subsequently
provide
the desired properties described above during repeated use of the scouring
article.
The controlled detergent release composition will provide excellent grease
cutting
properties with little skin irritation and will generally provide enhanced
detergency
2o when compared with the detergency of a comparable scouring article coated
with a
comparable loading of detergent but without the polyacrylamide.
The coatable polymer/detergent blend of the invention can be prepared, for
example, by blending an aqueous solution of polyacrylamide with an aqueous
solution of detergent such that the polyacrylamide comprises at least about 1%
by
25 weight of the total solids (dry weight) in the blend. More preferred are
those blends
having between about 1% and about 15% of the solids as polyacrylamide and,
most
preferred are those having between about 3% and about 10% of the solids as
polyacrylamide. When the solids of the polymerldetergent blend include at
least
about 3% polyacrylamide, the ei~ective life of the detergent in the scouring
or
3o cleansing pad is increased by a factor of about two or more over that of
similar
scouring articles which include only the detergent without the polymer. At
polymer
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levels above about 10% of the total dried solids, the higher polymer level
tends to
impart an undesirable slippery feel and may further complicate the processing
of the
blend. At the foregoing preferred ranges, the blend can easily be processed at
room
temperature with elevated temperatures required only for drying the blend
after it
has been applied to a porous pad or substrate.
It has been found that the weight ratio of detergent solids:polymer solids
within the polymer/detergent blend can be an important parameter in the
formulation of suitable blends for preparing cleansing articles according to
the
present invention. The weight ratios to formulate usable blends will include
to polymer solids:detergent solids ratios between about 1:9 and about 1:100
and
preferably between about 1:12 and about 1:30 and more preferably between about
1:13 and about 1:23. Within the above described preferred guidelines for
formulating the blend, the viscosity of the resulting blend prior to its
application will
typically be between about 3,000 and about 40,000 centipoise ("cps"), as
determined by a Brookfield viscometer at 25°C using a No. 4 spindle
rotated at 6 to
12 rpm, depending on the coating method being employed. The viscosity of the
blend is pH dependent and can be adjusted as needed by the addition of an
appropriate acid or base as well as by the use of an appropriate salt as a
viscosity
control agent. Citric acid and sodium hydroxide, for example, are a suitable
acid
2o and base, respectively, for achieving an adjustment to the viscosity by
changing the
pH. Such acids and bases can be used individually or in combination with a
salt
such as sodium chloride to achieve and thereafter maintain a suitable coating
viscosity. Other known acids, bases and salts may also be used and their
selection
and use is believed to be within the skill of those practicing in the field.
It is further contemplated that the substrate to be coated with the
polymer/detergent blend can include any of a wide variety of articles
including,
without limitation, those made of materials including sponge, paper, fabric,
plastic
fiber, plastic ribbon, metal fiber, metal ribbon, and composite structures
incorporating one or more of the foregoing materials. Exemplary of materials
made
of metal fibers is steel wool. Preferably, the substrate is a porous pad made
of
woven cloth or of nonwoven fabrics of varying density, fiber size and
thickness. All
-io-
CA 02205428 2006-03-02
60.557-5.520
such substrates are contemplated as within the scope of the invention and, the
foregoing list is intended to be illustrative and not limiting in any way.
Additionally,
the size and the shape of the article employed can also be varied over the
broad
range of sizes and shapes which are convenient and/or desirable to the users
or
consumers of the invention. Those skilled in the art will appreciate that the
criteria
for establishing comfort and ease of use will vary depending on the
contemplated
cleaning application for the finished product. The typical size of such
articles will
be sufficient, in general, to fit comfortably within the hand of the user with
sizes
varying over reasonable ranges to accommodate different hand sizes as well as
1o different cleaning applications. Some practical applications for the
articles of the
invention include kitchen scouring and cleansing wipes as well as floor
scrubbing
pads, for example.
The preferred substrate for the cleansing articles of the invention is a low
density, lofty, open, porous, nonwoven pad which can be used in a variety of
cleaning applications but, most typically, is used as a kitchen scouring pad.
Such a
nonwoven pad comprises a multiplicity of crimped or undulated, thermoplastic
organic filaments which are bonded together either at the opposite ends of the
article or by fiber to fiber bonding with a suitable adhesive material or by
thermal
bonding, for example. Nonwoven pads suitable for use in the invention include
2o those commercially available under the trade designation "Scotch-Brite"
available
from Minnesota Mining and Manufacturing Company of St. Paul, Minnesota.
Included within the preferred nonwoven articles used herein are those nonwoven
pads disclosed in United States Letters Patent Nos. 4,991,362 and 5,025,596.
As these patents
disclose, such pads comprise fibers having first and second ends and, the
fibers
within a single pad are arranged within the pad so that the first ends of the
fiber are
collectively bound together at one end of the pad while the second ends are
collectively bound together at the opposite end of the pad.
Although the nonwoven pads to be used in the invention are, in general, of
3o sufficient coarseness for effective use in scouring applications, the
abrasiveness of
the pad can be enhanced by adhering abrasive particles to the fibers of the
pads in a
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manner which increases the scouring ability of the article in certain uses.
The
application of such abrasive particles directly to the scouring pad is well
known in
the art. Additionally, it is contemplated that abrasive particles can be
included
within the polymer/detergent blend of the invention and thereby incorporated
within
the cleansing articles by the application of the blend to the nonwoven pads.
It is contemplated that all of the foregoing nonwoven pads are within the
scope of the invention as well as other substrates which are capable of
accepting the
coating of the polymer/detergent blend. The foregoing nonwoven articles can be
used as individual pads consisting solely of the nonwoven portion coated with
the
1o controlled detergent release composition or, the pad can comprise a
nonwoven
portion in conjunction with a wiping article or the like such as a nonwoven
which
has been laminated to another article such as a sponge, for example. Those
skilled
in the art will understand that the invention is not intended to be limited by
the type
of substrate selected for supporting the controlled detergent release
composition.
15 In the manufacture of the cleansing article, polyacrylamide powder may be
dispersed and dissolved in water to make an aqueous polymer solution which may
then blended with an aqueous detergent solution of one or more surfactants
under
moderate shear. The polyacrylamide will preferably comprise essentially all of
the
solids within the polymer solution and the total solids content of the polymer
2o solution will preferably be between about 3% and about 10% by weight. The
detergent solution may be prepared by dissolving surfactant in deionized water
to
give a solution wherein surfactant concentration is initially between about 1%
and
about 50% by weight prior to mixing with the polymer solution. The
polymer/detergent blend preferably comprises between about 20% and about 80%
25 of the detergent solution and between about 10% and about 60% of the
polymer
solution. It has been noted that the actual concentration of detergent in the
polymer/detergent blend does not appear to be critical as long as the
aforementioned preferred polymer solids:detergent solids weight ratio, after
drying,
is achieved in the final controlled detergent release composition within the
cleansing
3o article. Alternatively, the preparation of separate polymer and detergent
solutions
can be avoided, and the above ingredients can be blended together in a single
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solution so that the concentrations of the components provide a preferred
polymer
solids:detergent solids ratio.
Blending and application of the detergent/polymer blend is preferably carried
out at room temperature. However, polymer/detergent blends can be formulated
at
elevated temperatures as required.
Coloring agents, pearlizing agents, perfumes, fragrance oils, preservatives,
pigments and the like may be added to the blend as well as additional abrasive
particles to increase the scouring ability of the finished article. These
additional
ingredients are well known in the art and will not be further described. As
to mentioned, the polymer/detergent blend will typically have a viscosity
between
about 3,000 and about 40,000 centipoise which can be adjusted by the addition
of
an appropriate acid, base or salt. Acids such as citric acid have been used
with
acceptable results as well as bases such as sodium hydroxide, for example.
Suitable
salts include sodium chloride and sodium carbonate. The viscosity of the blend
will
be pH sensitive and any adjustment of the viscosity is normally made by taking
into
account the method by which the blend is to be applied to the substrate.
The blend may be applied to the substrate by one or more of a number of
known coating techniques such as roll coating, spray coating, immersion
coating,
injection coating and the like. The loading of the blend on the substrate will
vary
2o according to the intended use for the finished article. For household use
in kitchen
scouring or dishwashing pads, for example, an adequate coating is roughly
between
about 0.039 g/cm3 and about 0.052 g/cm3 which translates to between about 3.0
and about 4.0 grams (dry weight) for a conventional lofty nonwoven abrasive
pad
measuring approximately 5.1 cm (2 inches) by 7.6 cm (3 inches) with an
approximate thickness of about 2.0 cm (0.8 inch) and having a total volume of
about 77 cm3. Once the blend is applied to the substrate, the article is dried
in a
known manner to remove solvent. Heating in a conventional forced air oven at a
temperature of between about 200°F (93°C) and about 300°F
(149°C) for between 5
and 45 minutes is usually su~cient to evaporate the excess water and to fully
dry
3o the blend into a coating which is firmly adhered to the fibers of the
nonwoven
article. Drying may, of course, be accomplished by any other known means such
as
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by infrared heating or microwave heating, for example. Those skilled in the
art will
also appreciate that the drying conditions can be varied significantly
depending on
the equipment used, the total solids concentration in the polymer/detergent
blend
and the like.
The cleansing articles of the present invention provide a means for the ,
controlled release of detergent during cleaning operations, providing
excellent
grease cutting ability and good sudsing properties while extending the
effective life
of the detergent significantly. The manner in which the inventive articles are
manufactured and their improved performance features are further illustrated
in the
to following examples.
Examples
Test Procedures
Four test methods were employed in evaluating the relative performance of
the scouring articles made in the following Examples. These test methods were:
1. "Squeeze Test": In this test, a scouring article is passed through a
pair of air driven soft nip rolls which are 25.4 centimeters (10 inches) in
diameter and rotating at about 45 to 47 rpm, applying a pressure to the
article of between about 1.83 kg/cm2 and 2.18 kg/cm2 (between 26 and 31
psi) while a water stream is run over the rolls. The article is repeatedly
2o passed through the rolls until detergent foam is no longer detected by
visual
inspection. Toward the end of the test, the pad is also squeezed by hand to
remove excess water and the pad is again passed through the rolls until foam
from the detergent is no longer detected. The dry weight of the article is
recorded before and after the completion of the test to determine the
amount of material extracted from the article. The water passing over the
rolls was city water (St. Paul, Minnesota) run from the tap at a temperature
of about 36 to 38°C (97 to 1000 at a flow rate of about 20 to 25
milliliters
per second. All pads tested were run through the rolls, counting the number
of passes until detergent foam was no longer observed.
2. Soap Foam Life Test: A scouring article is placed within a 3.8 liter
(one gallon) glass jar filled with 1.9 liters (0.5 gallon) of tap water at a
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temperature of about 36 to 39°C (97 to 102°F). The jar is sealed
with'a
screw cap and the jar is placed on its side on a flat bed shaker (available
from Eberbach Corporation of Ann Arbor, Michigan) with the longitudinal
axis of the jar parallel to the line of movement. The jar and its contents are
agitated on the shaker which produces a reciprocating motion of 3.81 cm
(1.5 inches) for 60 seconds at a speed of 180 cycles per minute followed by
30 seconds at 280 cycles per minute. The jar was then removed from the
shaker and the level of the measurable foam was recorded as centimeters of
foam per one cycle. The pad was removed from the jar and set aside while
to the jar is rinsed and replenished with fresh water. The same procedure is
then followed until no measurable foam (e.g. less than 0.125 inch or 3.2
mm) is observed. For each of the pads tested, the total number of cycles
and the cumulative centimeters of foam were recorded and the cycles per
article were also normalized for the detergent loadings and reported as
cycles per gram of detergent.
3. "Oil Challenge Test": A more rigorous variation of the above Soap
Foam Life Test, referred to as the "Oil Challenge Test", was also performed
for at least some of the sample scouring articles. The test requires the
addition of a 1 milliliter aliquot of fresh cooking oil (vegetable oil was
used)
2o to the fresh water in the jar during each test cycle. This test is
otherwise
identical to the Soap Foam Life Test. The cumulative centimeters of foam
and the total number of cycles per article were recorded and the cycles per
article were also normalized for the detergent loadings and reported as
cycles per gram of detergent.
4. "Soap Solubility Test" In this test, the dry weight of the pad is
recorded and the pad is then placed within the cage of a cage type mixing
blade (Model HS-1 available from the Jiffy Mixer Company of Tustin,
California). The cage and the pad are placed in 3.8 liters (1 gallon) of tap
water within a 19 liter (5 gallon) polyethylene pail with the water
3o temperature at about 41 to 42°C (106 to 108°F). The cage is
centered within
the water solution in the pail and the mixer is turned on so that the cage and
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6.0557-.5520
the pad stir the water solution at 135 rpm for selected periods of 15
seconds, 30 seconds, 1 minute or 5 minutes. The pad is removed from the
water solution using forceps and placed on end on a rack for one minute to
ensure no further dripping from the pad. The pad is then dried to a constant
weight at 115°C (240°F) and the weight is recorded. Detergent
remaining
within the pad is subsequently rinsed from the pad through a series of slow
cycles in the flat bed shaker, described above, at a temperature of 38 to
42°C (100 to 108°F). The pad is dried to a constant weight and
the weight
percentage of detergent dissolved from the pad at each of the time periods is
1o calculated and reported.
Unless otherwise specified, the water used in all of the testing was tap water
supplied by the city of St. Paul, Minnesota. The water is of moderate hardness
at
about 85.6 to 102.7 milligrams per liter hardness (based on calcium carbonate,
for
example). During the testing, to avoid inconsistent data, all pads were
thoroughly
dried after coating and prior to measurement to allow the pads to equilibrate
to
room temperature conditions and to thoroughly dry the water soluble polymer.
Thorough drying of the pads is critical because the presence of excess water
in the
pads will lead to premature swelling of the polymer along with at least some
dissolution of the detergent, thereby adversely affecting the results of the
testing.
2o Ingredients
Ingredients used in the formulation of the scouring articles described in the
following Examples are identified by their chemical names and, when possible,
by
their trade designations. The trade designations shall be understood to have
the
following meanings.
TM
"Sulfochem ES-70" is the trade designation for a sodium lauryl ether
sulfate, an anionic surfactant, available from Chemron Corporation of Paso
Robles, California.
tM
"Amidex CME" is the trade designation for Cocamide MEAy a
superamide foam stabilizer also available from Chemron Corporation.
"CyanamefMN-300 LMW ' is the trade designation for a
polyacrylamide polymer having an average molecular weight (weight
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average) of around 5-6 million and available from American Cyanamid
Corporation.
TM
"Cyanamer P-21" is the trade designation for a polyacrylamide
polymer that is 90% nonionic with 10% anionic acrylate functionality,
having an average molecular weight (weight average) of around 200,000
and available from American Cyanamid Corporation.
"Polyacrylamide cat.#18,127-7" is the catalog designation of a
poiyacrylamide polymer having an average molecular weight of around 5-6
million and available from the Aldrich Corporation of Milwaukee,
Wisconsin.
TM
"Witcolate ES-3" is the trade designation for sodium lauryl ether
sulfate, available from Witco Corporation of New Jersey.
TM
"Emcol COB" is a trade designation for coco/oleamidopropyl
betaine available from Witco Corp.
"RhodamoX L" is a trade designation for lauramine oxide, available
from Rhone Poulenc of Cranbury, New Jersey.
TM
"Rhodamox LO" is a trade designation for lauramidopropylamine
oxide, available from Rhone Poulenc.
"AlkamideMC212" is a trade designation for cocamide MEA available
2o from Rhone Poulenc.
TM
"Biosoft D-40" is a trade designation for sodium dodecylbenzene
sulfonate available from Minnesota Solvents of Minneapolis, Minnesota.
TM
"Euperlan PK-771" is a trade designation for ethylene glycol
distearate available from Henkel Corporation of Ambler, Pennsylvania, and
used herein as a pearlizing agent.
Unless indicated otherwise, all concentrations listed in the following
Examples are given as weight percentages, and all of the nonwoven articles
used to
make the scouring pads in the Examples were of the type disclosed in the
aforementioned U.S. Patents 4,991,362 and 5,025,596, each pad measuring
3o approximately 5.1 cm wide by 7.6 cm in Length with a thickness of about 2
cm and
an approximate volume of 77 cm'. Viscosity determinations were made using a
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Brookfield viscometer at 25°C using a no. 4 spindle rotating at 12
rpm. The
polymer/detergent blends were roll coated onto the substrates to provide a
cleansing article with a loading of the controlled detergent release
composition as
indicated below.
Ex~m_ple I
A scouring article is made by first preparing a polymer/detergent blend to
have the following weight percentages in the dry solids of the blend: 63.96%
TM
Sodium lauryl ether (3) sulfate (Witcolate ES-3); 9.14% coco/oleamidopropyl
betaine (Emcol COB); 13.70% lauramidopropylamine oxide (RhodamoX LO); 4.57
to % Urea; 6.57% sodium chloride; 0.46% titanium dioxide pigment; 0.05
preservative ( commercially available under the trade designation "Actamer VI"
from Gray Products of Aurora, Ontario, Canada); 0.18% citric acid; and 1.37%
poiyacrylamide powder (Cyanamer N-300 LMW). The surfactants are blended
together first and dissolved in deionized water at room temperature to make a
detergent solution. The polymer powder is then blended into the detergent
solution
under low shear by hand mixing or using an electric mixer operated at a mixing
speed around 130 rpm until the polymer is thoroughly dissolved and the blend
is
homogenous. The liquid composition after the addition of the polymer will be
approximately 38% solids with approximately 4.3% of the solids as
polyacrylamide.
2o The viscosity of the final Liquid composition will be between 4,000 and
10,000 cps.
The polyacrylamide:detergent weight ratio in the dried solids is about 1:22.
The
polymer\detergent blend is roll coated on a nonwoven article at a wet loading
of
between about 8.2 and 9.0 grams per pad. The pad is oven dried to a constant
weight at a temperature between about 93 and about 149°C (200°F
and 300°F).
Example 2
Three scouring articles were prepared with polyacrylamide/detergent blends
according to the teachings of the invention. The detergent was first prepared
as an
aqueous solution of 49.63% deionized water, 15.25 % sodium lauryl ether
sulfate
(Sulfochem ES-70), 9.31% cocamide NLEA (Amidex CME) and 25.81% sodium
dodecylbenzene sulfonate (an anionic surfactant obtained from Chemron
Corporation). The total solids in the detergent solution was 36% by weight.
The
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polymer was prepared as a solution of polyacrylamide polymer (Cyanamer N-300
LMW) dissolved in deionized water with the concentration of the poiyacrylamide
at
8.00% by weight with no other ingredients in the solution. The solutions of
detergent and of polymer were blended under stirring at slow speed
(approximating
hand mixing), at room temperature, for approximately 25 minutes to prepare a
polymer/detergent blend consisting of 68.25% of the detergent solution and
31.75%
of the polyacrylamide solution. The fcnal % solids of the polymer/detergent
blend
was approximately 27.2%, with 9.3 % of these solids being poiyacrylamide. The
resulting blend was stringy and viscous (approximately 35,000 cps). The blend
was
roll-coated at room temperature onto three non-woven pads. The pads were dried
to constant weight in a forced air oven heated to about 115.5°C (240').
The
polyacrylamide/detergent weight ratio in the dried solids was about 1:9.75.
The
average dry loading of the controlled detergent release composition for the
two
pads that were squeeze tested was 0.054 glcm3. The loading for the third pad
z5 which was soap Iife tested was 0.046 g/cm3. The comparative test data is
set forth
in Example 7.
Example 3
Three more scouring articles were prepared following the procedures and
using the ingredients set forth in Example 2 except that the polymer/detergent
blend
2o included 72.50% of the detergent solution and 27.50% of the polyacrylamide
solution. The final % solids of the polymer/detergent composition was
approximately 28.4 %, with 7.7 % of these solids being polyacrylamide polymer.
This mixture was very stringy and viscous (approximately 28,000 cps). The
polyacrylamide/detergent weight ratio in the dried solids was about 1:12. The
25 average dry loading for the two pads which were squeeze tested was 0.059
g/cm3
and the loading for the third pad which was soap foam life tested was 0.048
g/cm3.
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Example 4
Three scouring pads were prepared following the procedures and using the
ingredients set forth in Example 2 except that the polymer/detergent blend
included
79.84% of the detergent solution and 20.16% of the polyacrylamide solution.
The
final % solids of the polymer/detergent blend was approximately 30.3%, with
5.3
of these solids being polyacrylamide polymer. This mixture was homogenous and
viscous (approximately 26,000 cps). The polyacrylamide/detergent weight ratio
in
the dried solids was about 1:17.95. The average dry loading for the two pads
that
were squeeze tested was 0.068 g/cm3. The loading for the third pad which was
l0 soap life tested was 0.061 g/cm3.
Example 5
Four scouring pads were prepared following the procedures and using the
ingredients set forth in Example 2 except that the aqueous polymer solution
was
prepared as 6.00% polyacrylamide (Aldrich cat.# 18, 127-7) and the
polymer/detergent blend included 69.68% of the detergent solution and 30.32%
of
the polyacrylamide solution. The final % solids of the polymer/detergent blend
was
approximately 26.9%, with 6.8 % of these solids being polyacrylamide polymer.
This mixture blended easily, resulting in a uniform mixture with a viscosity
of
approximately 12,000 cps. The polyacrylamide/detergent weight ratio in the
dried
solids was about 1:14.8. The average dry loading was 0.044 g/cm3 for the two
pads
that were squeeze tested as well as for the pads that were soap foam life
tested.
Example 6
Three "control" samples were prepared by roll coating a detergent solution
onto nonwoven pads as in the Examples 2-5. The detergent solution was
identical
to that used in the foregoing examples. No polyacrylamide solution was used
for
the controls. The average dry loading for the two control pads that were
squeeze
tested was 0.066 g/cm3; and 0.069 g/cm3 for the pad that was soap life tested.
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Example 7
Squeeze tests and Soap Foam Life tests were conducted for pads of the
Examples 2-6. The data from these tests were averaged and the averages are
summarized in Table 1.
Table 1
SQUEEZE SOAP
TEST' FOAM
LIFE
TEST
Pads Loading Total SqueezesLoading Total Total Cycles
of (g/cm') squeezesper (g/cm3) cycles cm per
Example gram of foam gram
detergent detergent
2 0.054 141 34 0.046 5 26.9 1.4
3 0.059 182 41 0.048 5 28.4 1.3
4 0.068 190 37 0.061 8 56.9 1.7
0.04 202 59 0.044 5 27.9 1.5
6 (control)0.066 94 19 0.069 3 29.5 0.6
1. 'W a Squesze'fest data is an average for two pads per Example.
2. The Soap Foam Life test data of Example 5 es an average for two pads. The
other data for this test was collecltd for one pad
for cash remaining example.
The squeezes per gram of detergent and the cycles per gram detergent for
1o Examples 2-6 illustrates that the polyacrylamide significantly increases
the effective
life of the detergent within the scouring pads of the invention. The number of
squeezes per gram of dry soap and the cycles per gram detergent are
significantly
increased upon incorporation of the polymer, reflecting enhanced detergency
and
foaming at lower levels of surfactant. Similarly, the effects of viscosity and
adequate mixing to achieve a smooth and homogeneous mixture, is reflected in
the
better performance of the pads of Examples 4 and 5.
The following examples will describe formulations in which both polymer
and detergent are well-dissolved in one another.
Example 8
Three scouring articles were prepared with a polyacrylamideldetergent
blend. The detergent was first prepared as an aqueous solution by dissolving
in
TM
deionized water a solids blend of 68.95% sodium lauryl ether sulfate
(Witcolate ES-
TM
3), 9.85% coco/oleamidopropyl betaine (Emcol COB), 14.77% lauramido
TM
propylamine oxide (Rhodamox LO), 4.92% tallowamine ethoxylate nonionic and
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1.51% sodium chloride. The total solids in the detergent solution was 36% by
weight. The polyacrylamide was a low molecular weight polymer (Cyanamer P-21)
which was added directly to the detergent solution slowly, stirring at slow
speed
(approximating hand mixing) at room temperature until homogenous. The
resulting
polymer/detergent blend was 95.01% of the detergent solution and 4.99%
polyacrylamide. The final % solids of the poiymer/detergent blend (dry weight)
was
approximately 37.4%, with 15.5 % of these solids being polyacrylamide. This
resulting mixture was homogeneous and the final viscosity was between 4,000
and
10,000 cps. The resulting polymer:detergent composition was then roll-coated
at
to room temperature on nonwoven articles. The pads were dried to a constant
weight
in a forced air oven heated to about 115.5°C (240°F). The
polymer/detergent
weight ratio in the dried solids was 1:6.5. The average dry loading of the
controlled
detergent release composition for the three pads was 0.052 g/cm'.
Example 9
Six scouring articles were prepared following the procedures and using the
ingredients set forth in Example 8 except that the polymer used was a higher
molecular weight poiyacrytamide (Cyanamer N300 LMW). The polyacrylamide
was prepared as a solution of polyacrylamide powder dissolved in deionized
water
at a concentration of 8% poiyacrylamide (by weight) with no other ingredients
in
2o the polymer solution. The polymer/detergent blend was 83.23% of the
detergent
solution and 16.77% of the polyacrylamide solution. The final percent solids
of the
polymer/detergent composition was approximately 3 I .3% with 4.3 % of the
solids
being the polyacrylamide polymer. The poiymer/detergent weight ratio in the
dried
solids was I :22.5. The average dry loading for the three pads that were
squeeze
tested was 0.053 g/cm~. The dry loading for the pad that was soap foam life
tested
was 0.042 g/cm3; and the average dry loading for the two pads that were oil
challenge tested was 0.041 g/cm'. Comparative test data are tabulated in
Example
13.
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Example 10
Five scouring articles were prepared following the procedures and using the
ingredients set forth in Example 8 except that the polymer used was a higher
molecular weight poiyacrylamide (Cyanamer N300 LMW). The polyacrylamide
was prepared as a solution of polyacrylamide powder dissolved in deionized
water
at a concentration of 8% polyacrylamide (by weight) with no other ingredients
in
the polymer solution, The polymer/detergent blend was 75.37% of the detergent
solution and 24.63% of the polyacrylamide solution. The final percent solids
of the
poiymer/detergent composition was approximately 29% with 6.8% of the solids
1o being the polyacrylamide polymer. The poiymer/detergent weight ratio in the
dried
solids was 1:13.78. The average dry loading for the three pads that were
squeeze
tested was 0.052 glcm3, 0.042 g/cm3 for the pad that was soap foam life tested
and
0.045 g/cm3 for the pad that was oil challenge tested. Test data are tabulated
in
Example 13.
Example 11
Ten scouring articles were prepared foIfowing the procedures and using the
ingredients set forth in Example 8 except that the polymer used was a higher
molecular weight poiyacrylamide (Cyanamer N300 LMW). The poiyacrylamide
was prepared as a solution of polyacrylamide powder dissolved in deionized
water
2o at a concentration of 8% polyacrylamide (by weight) with no other
ingredients in
the polymer solution. The poiymer/detergent blend was 80.27% of the detergent
solution and 19.73% of the polyacryiamide solution. The final percent solids
of the
poiymer/detergent composition was approximately 30.5% with 5.2% of the solids
being the poiyacrylamide polymer. The poiymer/detergent weight ratio in the
dried
solids was 1:18.3. The four pads that were squeeze tested had an average dry
loading of 0.042 g/cm3. The average dry loading for the three pads that were
soap
foam life tested was 0.040 g/cm~ ; and 0.040 g/cm3 for the remaining three
pads that
were oil challenge tested. Test data are tabulated in Example 13.
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Examnle 12
An additional seven "control" pads were made according to the procedure
and the ingredients used in Example 8. However, the control pads were made
only '
with the detergent solution of Example 8 and in the absence of any
polyacrylamide .
The average dry loading for the three pads that were squeeze tested was 0.063
g/cm3. The average dry loading for the two pads that were soap foam life
tested
was 0.058 g/cm3 and the average for the two oil challenge tested pads was
0.056
g/cm3. These pads were used as the controls in the testing set forth in the
following
Example 13.
l0 Examnle 13
The pads of Examples 8-11 were comparatively tested against the control
pads of Example 12 to screen the effect of the lower molecular weight
polyacrylamide of Example 8 on the performance of the article and to
simultaneously compare the performance of the lower molecular weight
polyacrylamide with the higher molecular weight polymer of Examples 9-11.
Testing of the foregoing articles consisted of squeeze testing of all the
articles as
well as soap foam life testing and oil challenge testing of the articles of
Examples 9-
12. The squeeze test data is summarized in Table 2 and, the soap foam life and
oil
challenge data is summarized in Table 3.
Table 2
SQUEEZE TEST'
Pad of ExampleTotal number Squeezes per Detergent loading
of gram of (g/cm3)
squeezes detergent
8 93 23 0.052
9 222 55 0.053
10 256 64 0.052
11 257 79.5 0.042
12 (control) 181 37 0.063
1. The squeeze test data tbr l;xampies x, y, to ano 11 ~s an average for wee
pans per cxamp~e, t ne ua~a ror me pay ~.
Example 11 is an average for four pads.
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Table 3
SOAP ~ OIL
FOAM CHALLENGEZ
LIFE
TEST'
Pad Total Total CyclesAverage Total Total Cycles Avg.
of cycles cm per dry cyclescm of per dry
Example of foamgram loading foam gram loading
detergent(g/cm3) detergent(g/cm3)
8 no data no
data
9 10 44.2 3.1 0.042 6 27.7 1.9 0.041
12 49.5 3.8 0.042 5 25.1 1.4 0.045
11 9 26.3 2.9 0.040 5 18.3 1.6 0.040
12 9 36.3 2 0.058 5 24.6 1.1 0.056
(control)
1. The data for the soap foam hfe test is an average for 3 pads from Example
11 and two pads from Example 12. The data for
Examples 9 and 10 was collected using one pad from each Example.
2. The data for the oil challenge test is an average for 2 pads from Example
9; 3 pads from Example 11; 2 pads from Example
5 12; and one pad from Example 10.
The performance testing set forth in Table 3 demonstrates that the lower
mnlerr,~~;lar ::'elgla polya~ j'lamlde fail8 to pr:duCe the d°celred
result lit t he
polymer/detergent blend of extending the effective life of the detergent
within the
to scouring pad. The tallowamine ethoxylate nonionic surfactant produced a
more
stable foam in the controls with foaming being significantly reduced upon the
addition of the low molecular weight polyacrylamide. It is believed that the
molecular weight of the polyacrylamide used in Example 8 was not high enough
to
slow the dissolution of the polymer in water, but was effective in tying up
the
detergent and thereby decreasing the overall detergency of the formulation.
The
use of the higher molecular weight polyacrylamide in the pads of Examples 9-12
was effective in extending the useful life of these pads, as is shown by the
Squeeze
Test data of Table 2. As shown in Table 3, the substitution of the higher
molecular
weight polymer in the polymer/detergent blend, at various polyacrylamide
2o concentrations, enhances foaming and improves the detergency of the blend,
allowing a lower loading of the blend on the scouring article than would
otherwise
be required in the absence of the polymer.
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Example 14
An aqueous detergent blend was first formulated by blending the ingredients
listed below:
TM
Sodium lauryl ether sulfate (lVitcolate68.95%
ES-3)
TM
Coco/oleamidopropyl betaine (Emcol 9.85%
COB)
TM
Lauramidopropylamine Oxide (Rhodamox 14.77%
LO)
Sodium Sulfate 4.92%
Titanium Dioxide 0.29%
Citric Acid 1.22%
to The detergent solution was 35% solids. An aqueous polyacrylamide
solution was prepared at 6% polyacrylamide (Cyanamer N-300 LMW) in deionized
water. The resulting polyacrylamide solution was thoroughly blended into the
detergent by blending 20.62% of the poiyacrylamide solution and 79.38%
detergent
solution until the poiyacrylamide was dissolved and the blend was homogenous.
The viscosity of the liquid poiyacrylamide/detergent blend was approximately
4,300
cps. Incorporation of the polymer solution into the detergent solution gave a
composition that was 29% solids with 4.26 % of those solids as poiyacrylamide.
The composition was then roll coated onto ten nonwoven articles and oven dried
at
a temperature of about 115.5 °C (240 °F) to a constant weight.
The average dry
loading of the controlled detergent release composition on the pads was 0.042
g/cm3 for two of the pads that were subsequently squeeze tested. Eight of the
pads
were used in the soap life and the oil challenge testing having an average
loading of
0.045 g/cm3. Comparative testing is set forth in Example 16. The
polymerldetergent weight ratio in the finished dried product was 1:22.
Ex~mnle 15
Seven control samples were made according to Example 14 using the same
detergent blend (without added polyacrylamide). The average dry loading for
the
controls was 0.065 g/cm3 for the three pads which were subsequently squeeze
tested and 0.055 g/cm3 for the four pads used in the soap foam life and oil
challenge
3o testing of Example 16.
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605.57-5520
Example 16
Comparative testing of the samples of Examples 14 and 15 was conducted
and is summarized in Tables 4 and 5. In addition to the samples of Examples 14
and 15, additional commercially available scouring pads were included in the
TM
testing. "SOS" is a commercially available steel wool scouring pad
manufactured
TM
by Clorox Corporation of Oakland, California. "Never Rust" is trade
designation
for a commercially available scouring pad manufactured and sold by the
Minnesota
Mining and Manufacturing Company of St. Paul, Minnesota as part of its "Scotch
TM TM
Brite" line of products. The soap loading for both the "Never Rust" and for
the
TM
to "SOS" pads was determined by initially weighing the pads and comparing the
initial
weights to a final weight taken after the detergent or soap was completely
rinsed
from the pad. The loading for the two "Never Rust'Mpads was between 0.040
g/cm3
TM
and 0.052 g/cm3 ; and for the "SOS" pads was between about 0.058 and 0.084
g/cm3 assuming equivalent pad volume of 77cm3.
Table 4
SQUEEZE
TEST'
PAD Total number Squeezes per Average dry
of gram loading
squeezes detergent (or (g/cm3)
soap)
"SOS"T"~ 133 24 0.072
Example 257 79 0.042
14
Example 206 41 0.065
I S
"Never Rust"T"'84 27 0.040
i. i ne aua for txampte t4 ~s an average for two pans: ttute peas for txample
t~: twcive pads for the "tvcver Rust" pads; and
trn "SOS" pads.
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CA 02205428 2006-03-02
60557-520
Table S
SOAP FOAM OIL CHALLENGE
LIFE
TEST
PAD Total Cycles Total Total Cycles Total
per cm per cm
number gram foam number gram foam
of of
cycles detergent cycles detergent
"SOS"TM 1 0.2 6.35 1 0.2 6.35
Example 12 3.4 43.4 7 2.0 23.1
14'
Example S 1.2 37.1 6 1.4 28.2
15~
"Never 6 1.5 21.6 3 0.76 16.5
TM
Ru st"
1. Eight pads of Example 14 were used . four for the soap foam life test and
tour for the oil challenge (avg. dry loading 0.045
glan'). The reported results are an average.
2. Four pads of Example 15 were used, one in the soap foam life test and three
in the oil challenge (avg. dry loading 0.055
glom'). The reported results are an avenge.
The data in Tables 4 and 5 illustrate the improved performance of pads
made according to the teachings of the present invention. Of the pads tested
in
Example 16, the pad of Example 14 clearly showed the best performance, giving
1o test values (when corrected for the loading of detergent in the various
articles being
tested), nearly twice those of the control samples or the commercial pads. The
results indicate the superior detergency and foaming of the polymer/detergent
blends of the invention.
Ex:Imnle 17
15 Soap solubility testing was conducted for 12 additional pads made according
TM
to Example 14 and for several control pads consisting of 14 "Never Rust" pads
and
TM
13 "SOS" pads (described above in Example 16). Additionally, 12 calcium
stearate
pads were prepared using the same detergent formulation as in Example 14 but
in
the absence of the polyacrylamide polymer. In the calcium stearate pads, a
2o detergent and fatty acid mixture was prepared by mixing 85% of the
detergent
solution of Example 14 with 1 S% calcium stearate soap with the resulting
mixture
giving a pad having a detergent/soap coating that was expected to be
intermediate
in performance between the poiymer/detergent pads of the invention and a fatty
acid
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CA 02205428 2006-03-02
605,57-520
TM
soap product, such as the "SOS" pad. The pads were rigorously tested to
compare
the solubility in water of the various soap and detergent formulations. The
solubility testing was conducted at an elevated temperature (42°C) and
the data is
set forth in Table 6. Several of each type of pad tested were run for each of
the
indicated time periods and the data is an average for the total number of pads
tested. The actual number of each type of pad tested is shown in parentheses
adjacent the tabulated data.
Table 6
SOAP SOLUBILITY
TESTING
PAD % dissolved % dissolved % dissolved % dissolved
@ @ @ @
15 seconds 30 seconds 60 seconds 5 minutes
"Never Rust"TM74.2 (S) 89.5 (3) 95.4 (3) 99 (3)
"SOS"TM 44.6 (3) 60 (3) 70.2 (3) 92.1 (4)
Example 66.2 (3) 66 (3) 79.9 (3) 95.4 (3)
14
Ca Stearate55.5 (3) 75.1 (3) 81 (3) 94.8 (3)
1o The data set forth in Table 6 indicate a desired decrease in the rate of
water
solubility (without regard to the foaming or detergency) of the
polymer/detergent
TM
blend of the invention compared with the polymer-free "Never Rust" pads as
well as
the calcium stearate control pads. The test method, however, does not take
into
TM
account surface area effects relevant in the comparison with the "SOS" pads.
The
TM
"SOS" pads each have a very low surface area coating of soap which, in turn,
slows
the solubility of the soap in water. The roll coating of the other pads tested
provides a high surface area coating, allowing for faster dissolution of the
soap or
detergent in water. Despite these differences, the rate of dissolution of the
poiymer/detergent blend of the invention satisfactorily approaches the
dissolution
z0 rate of a fatty acid soap. Moreover, those skilled in the art will
appreciate that the
fatty acid soaps are typically less effective in certain applications (e.g.
dishwashing)
than are synthetic detergents such as those employed in the present invention.
As is
shown in the various examples, the invention provides a poiymer/detergent
formulation which is desirably less soluble in water than conventional
detergent
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CA 02205428 1997-OS-15
WO 96/18718 PCT/US95/14708
formulations and which provides better detergency and foaming than either the
conventional detergents (e.g. without a polyacrylamide binder) or the fatty
acid
soaps.
Although the preferred embodiments of the invention have been discussed
and described in detail, those skilled in the art will appreciate that changes
and
modifications to the described embodiments can be made without departing from
the true spirit and scope of the invention, as defined in the following
claims.
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