Note: Descriptions are shown in the official language in which they were submitted.
1 3343~0
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NONWOVEN WIPE IMPREGNATING COMPOSITION
! ~ACKGROUND OF THE INVENTION
1. Fleld of the Inventlon
The invention relates to nonwoven wet wipes and
more specifically to nonwoven wipes impregnated with an aqueous
non-alcoholic composition in which the preservative system
for the impregnated wipe comprises potassium sorbate, citric
acid, disodium ethylenediaminetetraacetate and a cationic
agent selected from polyhe~amethylene biguanide hydrochloride
and poly[oxyethylene~dimethyllminio)ethylene(dimethyliminio)eth-
ylene dichloridel.2. Information Disclosure Statement
Various forms of nonwoven impregnated wipes are
available and have been suggested for performing a wide variety
of tasks, euch as for cleaning hard surfaces, cleansing the
hande and other areas of the body and delivering active ingred-
ients to variou~ surfaces, both animate and inAni ste.
In the case of nonwoven impregnated wipes adapted
for cleaning hard and skin surfaces, the impregnant generally
i8 aqueous based. Such wipes are marketed ready for use either
in individual packet form or in bulk form in suitable dispeneers
from which individual wipes can be withdrawn as needed. What-
ever the form of packaging, the wipes are etored for ~ubstantial
periods of time prior to use and therefore need to be protected
against microbial contamination and deterioration to which
they are readily susceptible. One common method to achieve
this is to incorporate a suitable chemical preservative system
in the liquid composition employed to impregnate the nonwoven
wipe.
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Preservative systems which have been employed in
a number of aqueous impregnating compositions for nonwoven
wipes have included ethyl alcohol which is well known for
its antiseptic effect. One ~uch preservative system which
S has provided excellent results comprises sorbic acid, citric
acid and ethyl alcohol. However, the ethyl alcohol generally
is employed in such preservative systems at concentrations
above five weight-percent of the impregnating composition.
PrQsently there is a trend to formulate impregnating
compositions for nonwoven wipes which avoid~ the use of ethyl
alcohol because manufacturers of wet/moist wipes perceive
that many consumers would prefer alcohol-free wipes, particular-
ly those which are primarily intended for use in personal
hygiene, especially baby wash cloths for which there is a
lS sub~tantial market. However, a problem arises in eliminating
ethyl alcohol from sorbic acid - citric acid - ethyl alcohol
preservative systems for nonwoven wipes in that the combination
containing only sorbic acid and citric acid does not always
provide adequate protection against microbial contamination
and deterioration.
U.S. Patent 4,732,797 discloses a liquid preserving
composition for a fibrous wiper consisting essentially of
a mixture of citric acid and sorbic acid as the preservative
component, water and optionally ingredients selected from
skin moisturizers and fragrances.
_3_ ~ 3 3 4 3 2 0
Wlper~ having incorporated thereln a cationlc antimi-
crobial agent have been descrlbed, for example, in U.S. Patents
3,264,1a~, 4,615,937 and 4,67~,704, di~cus~ed herelnbelow.
U.S. Patent 3,264,188 discloses a sanitary lmpregnated
skin wlper for proctologlcal use comprising a facial grade
creped tls~uQ having di~per~ed therethrough a mineral oil
and an emulslfier ~uch as triethanolamine oleate, which wlper
may include a bacterlostatic agent, benzalkonium chlorlde
being a preferred bacteriostatic agent.
U.S. Patent 4,615,937 disclose~ an antimicrobially
active nonwoven web wherein the antimicrobial agent i8 substan-
tive both to the fibers and the binder in the web and preferab-
ly i8 an organo-sllicon quaternary ammonium salt.
U.S. Patent 4,678,704 dlscloses an impregnated fabric
material comprising a fabric ~ub~trate, which may be woven
or nonwoven, to which haa been bonded an active cationic impreg-
nant and an anionic indicator dye in combination with a further
cationic component. Nonionic fiurfactants, chelating agents
and fragrances may also be included in the impregnated fabric.
Example~ of the cationic materials which are di~closed are
quaternary ammonlum compounds, bisguanides and polymeric blsguan-
ide ~uch aB polyhexamethylene bisguanide hydrochloride.
U.S. Patent 4,587,266 discloses the UBe of polyhexa-
methylene biguanide hydrochlorides as antimicrobial agent~
in combinatlon with certaln amlne oxlde~ in aqueous antlmicrobl-
al compositions. The polyhexamethylene biguanide hydrochlor-
ides are ldentified as being commercially available from ICI
Americas Inc. under the trademark Cosmocll CQ.
_4_ 1 334320
A currently commercially available personal cleansing
wipe product lists its ~ey ingredients and their functions
as follows:
KEY INGREDIENT FUNCTION
5 Demineralized Water Moisturizes tender skin
Propylene Glycol
PEG-75 Lanolin* . Softens skin
Cocoamphodiacetate Cleans and soothes skin
Polysorbate 20
10 Methylparaben Maintains product purity
2-Bromo-2-nitropropane-1,3-diol and freshness
Propylparaben
Fragrance Plea8ant non-irritating scent
*a polyethylene glycol derivative of lanolin with an average
Of 75 moles of ethylene oxide
SU~IMARY OF THE INVENTION
In order to enhance the antimicrobial effect of
the combination of sorbic acid and citric acid in a preservative
system for moist nonwoven wipes, various types of commercially
available cationic biocides were investigated for inclusion
in the preservative system because of their well known substan-
tivity for nonwoven fabrics. Unfortunately, the inclusion
of the cationic biocides resulted in an undesirable slippery
feel being imparted to the impregnated nonwoven wipe, especially
those wipes the fiber content of which contains a significant
portion of rayon or rayon-polyester blends. However, it was
surprisingly found that incorporation of either of two specific
cationic biocides greatly minimized the slippery feel of the
wet wipe.
~ ~5~ 1 3 3 4 3 2 0
Thus in one aspect of the invention there is provided
'an aqueous composition for impregnating a nonwoven wipe compris-
ing from about 0.02 to about 0.25 weight-percent of potassium
sorbate, from about 0.05 to about 0.20 weight-percent of citric
5 acld, from about 0.02 to about 0.20 w~ight-percent o disodium
ethylenedlaminetetraacetate, from about 0.03 to about 0.24
weight-percent of a cationic biocide selected from the group
consisting of (a) polyhexamethylene biguanide hydrochloride
and tb) poly[oxyethylene(dimethyliminio)ethylene(dimethyl-
iminio)ethylene dichloride]; and the remainder to 100 weight-per-
cent water, wherein the pH of the composition is from about
3.5 to about 4.5.
In another aspect of the invention there is provided
a moistened wipe comprising a flexible absorbent nonwoven
substrate impregnated with the aqueous composition defined
hereinabove.
DETAILED DESCRIPTION OF THE INVENTION
INCLUDING THE PREFERRED EMBODIMENTS
The aqueous composition of the invention is employed
as an impregnant for flexible absorbent nonwoven fabric~ in
the manufacture of moist wipes useful for cleaning and/or
delivering active agents to animate or inanimate surfaces.
The aqueous composition is comprised of water having dissolved
therein a preservative system specifically adapted to prevent
microbial deterioration of the moist wipe, which is readily
susceptible to microbial deterioration in the absence of a
suitable preservative. The preservative system is comprised
~............... _...... .... . . . .
1 334320
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of pot~s~ium ~orbate, di~odium ethylenediaminetetraacetate
(dlsodlum ~DTA), a catlonlc blocide selected from two speciflc
agent~ de~crlbed more fully hereinbelow and citric ~cid.
The potas~ium sorbate is employed in the aqueous
compo~itlon at a concentratlon of from about ~.~2 to about
~.25 percent by weight of the aqueous composition. The antimi-
crobial effect contributed by the ~orbate i~ due primarily
to sorbic acid to which the sorbate is converted in ~itu at
the pll level employed in the aqueou~ composition as discussed
hereinbelow.
The difiodium ethylenediaminetetraacetate enhances
the effect of the preservative ~ystem. It 18 employed at
a concentration of from about o.n2 to about 0.20 percent by
weight of tlle compo~ition.
The catlonic bioclde i~ selected from polyhexamethyl-
ene biguanlde hydrochloride and poly[oxyethylene(dimethylimin-
io)ethylene~dimethyliminlo)ethylene dlchloridel. Polyhexameth-
ylene biguanide hydrochloride is a known biocide with a wide
spectrum of antimicrobial activity and i8 commercially available
as a 20~ w/w aqueou~ solution from ICI Americas Inc., W~lmington,
Delaware under the trademark COSMOCIL CQ. It can be represented
by the general formula:
flCL.N112(Cf{2)3~--(C~2)3-N~-Cj-N~I-C-NH-(CH2)3- -~CH2)3-NH-C-NH-CN
NH NH.f3CL n NH
in which n has an average value such that the molecular weight
iB 1000-1400. Poly[oxyethylen~dimethyliminio)ethylene~dimeth-
yliminio)ethylene dichloridel is a known broad ~pectrum microbio
1 334320
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clde and i8 commercially available a~ a 60~ aqueous concentrate
from auc~man Laboratories, Inc., Memphis, Tenne~see under
,the tradename WSCP. It ha~ a repeat unit structure as follow~:
CH3 Cl- CH3 Cl-
--O-cH2-cH2-N+-cH2-c~ +-C1~2-CH2
C~l~ CH3 - n
ln which n ha~ an ~verago v~lue ~uch that the molecular weight
1B 3000-4000.
~ho ¢atlonlc blocide~ are mployed at a concentration of rom
about 0.03 to about 0.24 percent ~y welght (act~ve basi~) of
the aquoou~ ¢ompoaition.
The pH of the aqueous conlpoBition should be in the
range of from about 3.5 to about 4.5 and preferably from about
4.0 to about 4.3. As disclosed hereinbefore, the antimicrobial
activity derived from the use of potas~ium ~orbate i~ due
primarily to undis~ociated sorbic acid which iu formed ln
filtu in the pH range of 3.5 to 4.S. Citric acid is employed
in the aqueous compo~ition as a p~l ad~uster in an amount that
ensures that the pH of the aqueous composition will fall in
the range of from about 3.5 to about 4.5. -A pH in this range
can be obtained when citric acid i~ employed at a concentration
of from about O.OS to about 0.20 percent by weight of the
aqueou~ compo~ition.
Depending on the particular u~e intended for a w$pe
impregnated with the aqueous compo~ition of the invention,
optional ingredients may be included in the aqueou~ compo~ition.
Thus a wipe intended for cleansing the ~kin may
include skin moisturizers/humectant~ ~uch as propylene glycol,
1 334320
glycerin and sorbitol; skin softeners/emollients such as ethoxy-
lated lanolin, ethoxylated glucose, silicone oils, mineral
oil and fatty acid esters; botanical extracts such as witch
hazel extract, aloe vera gel and chamomile extract; and perfumes
and fragrances. The concentrations of such optional ingredients
will, based on the weight of the final composition, fall in
the ranges of 0.2 to 10 weight-percent for skin moisturi2ers
and humectants, 0.02 to 5 weight-percent for skin softeners
and emollient~, 0.01 to 50 weight-percent for botanical extracts
and 0.01 to 2 weight-percent for perfumeQ and fragrances.
Surfactants and cleanser optionally may also be
included in the aqueous compositions of the invention. The
surfactant may be an amphoteric, such as cocoamphodiacetate
which is commercially available from several sources or a
nonionic, such as a polyethylene glycol ether of glycerol
cocoate, polyoxyethylene polyoxypropylene block polymers,
or a polymer of dimethylsiloxane with polyoxyethylene and/or
polyoxypropylene side chains, all commercially available.
The surfactant will generally be employed at a concentration
of 0.02 to 10 percent by weight based on the weight of the
aqueous composition.
The substrate employed in the moistened wipe of
the invention is a fibrous flexible absorbent nonwoven sheet
material consisting es~entially of cellulosic fibers or blends
of cellulosic fibers such as rayon and cotton fibers or blends
of such cellulosic fiber6 with one or more synthetic fibers
such as polypropylene, polyethylene, polyester and nylon fibers.
.
1 334320
Such blend~ may also include wood pulp fibers. Binder~ gener-
ally are employed to bind together the fiber~ thus en~uring
that the finished nonwoven ~heet has adequate wet strength.
Such binders are, for example, acrylic polymerfi, ethylene
vinyl acetate polymers, vinyl acetate copolymers and ~tyrene
butadiene polymer~. Such nonwoven materials and processes
for their manufacture are well known in the art. Proce~ses
for manufa¢turing ~uch nonwoven ~heet material~ include carding,
air laying, w~ter entanglement, thermal bonding and wet laying.
The moi~tened wipe of the invention can be prepared
by applying the aqueous composition according to the invention
to the flexible absorbent nonwoven sub~trate by a variety
of well known methods such as by spraying, padding, printing
and gravity application. Preferably the loading of the aqueous
compo~ition i~ from about two times (200~) to about S times
~500~) the wei~ht of the nonwoven ~ub~trate, and more prefer-
ably about three and one-half time~ (350%) the weight of the
nonwoven substrate.
The aqueous composition of the invention can be
prepared conveniently by the following procedure:
All optional ingredients, except the plant extract~,
to be included in the composition are combined and mixed until
a clear mixture is obtained. The re~ulting mix iB added with
effiaient stirring to approximately 95~ of the formula amount
of water and to thi~ i5 added with ~tirring, individually
and in the order listed, the plant extract, if any, the disodium
ethylenediaminetetraacetate, the cationic biocide and the
pota~sium ~orbate. Citric acid is then added to the ~tirred
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batch in an amount sufficient to adjust the pH to 3.5 to 4.5.
The remainder of the formula amount of water i8 then added
with stirring.
Although the major amount of water employed in the
composition is deionized water, it will be appreciated that
minor amounts of water are or may be derived from certain
commercially available ingredients which are in some cases
supplied as aqueous solutions or concentrates.
The moistened wipe of the invention may be used
to clean, or deliver active ingredients such as sunscreens,
insect repellants, etc., to animate and/or inanimate surfaces.
Thus they may be used to clean the hands or other skin area~
of the body or as baby wipes during diaper change as well
as for cleaning various hard surfaces such as kitchen counter
lS tops, toilet bowls, sinks, etc.
The moistened wipes of the invention should be packag-
ed in a manner which will maintain them in a moist condition.
A variety of well known packaging methods are available. For
example, they may be individually packaged in moisture impervi-
ous envelopes or packaged in bulk form in canisters provided
with suitable dispensing opening~. When packaged in bulk
~orm they may be provided as separate sheets, e.g., in inter-
leaved form, or in the form of interconnected sheets from
which individual sheets readily may be separated. In the
latter case, reference is made to U.S. Pat. No. 4,017,002.
The invention i8 further illustrated by the following
examples without, however, being limited thereto.
D.N. 5341
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EXAMPLE 1
An aqueous composition according to the invention
was formulated, using the general procedure described herein-
above, as follows:
5 Ingredient ~ by Weight
Propylene Glycol 0.500
PEG-60 Lanolin (50% solution)a 0.10~
Miranol~C2M Conc. NP-PG (3~ active)b 0.100
Perfume 0.475
Aloe Vera Gel ~l:10)C 0.010
Cosmocil CQ (20% active)d 0.700
Potassium Sorbate 0.140
Disodium EDTA Dihydrate 0.100
Citric Acid 0.100
Deionized Water 97.775
100. 000
pH 4.1
a) CTFA Adopted Name;commercially available from Croda, Inc.,
New York, New York under the trademark SOLAN-50% ~50~ active)
b) 3~% aqueous ~olution ~containing a small amount of propylene
glycol) commercially available from Miranol Inc., Dayton, New
Jersey;active is cocoamphodiacetate that conforms generally
to the formula;
Rco-N~cH2cH2~l-c~2cH2ocH2co2Na
CH2COONa
c) Commercially available from Dr. Madis Laboratories, Inc.,
South Hacken~ack, New Jersey as Veragel~ Liquid 1:10
d) Polyhexamethylene biguanide hydrochloride; commercially
available from ICI ~mericas Inc. (See general formula of
active disclosed hereinbefore)
The aqueous composition of Example 1 exhibited excel-
lent preservative activity in a 4 week challenge te~t again~t
Staphylococcus aureus, Psuedomona~ product isolate, yeast
product isolate and Aspergillus niger.
Moistened wipes in accordance with the invention
were prepared by impregnating a flexible absorbent nonwoven
substrate with 350% of its weight of the aqueous composition
of Example 1. A gravity application procedure was employed
a~ followss
D.N. 5341
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The aqueous composition of Example 1 (196g) was
placed in a cylindrical canister and a coreless roll of flexible
absorbent nonwoven fabric (56g) comprised of 40 dry wipes
(5.75" x ~.0") was placed in the cani~ter with one end immersed
in the liquid. The canister was capped with a plastic cap
and wa~ then inverted and maintained in the inverted position
for a minimum of three days to ensure complete absorbtion
and uniform distribution of the aqueous composition into the
coreles~ roll of fabric. The canister then was inverted to
the upright po~ition.
The flexible absorbent nonwoven fabric employed
in the foregoing procedure for making the moist wipes was
a 70/30 blend of rayon and polyester flbers which was processed
into uniform web form by a carding machine. The web then
lS was saturated with an aqueous dilution of an acrylic binder
(available commercially from Rohm and Haas Company, Inc.,
Philadelphia, Pennsylvania under the trademark Rhoplex NW-1402),
the amount of binder being such as to provide 20~ w/w of the
finished nonwoven fabric. The treated web was then dried
and hea~ed to 300F to cure the binder. The finished nonwoven
fabric, having a basis weight of 40g/sq. yd., was then slit
and cut into the desired dimension.
The moistened wipes 80 obtained were quite acceptable
with respect to ~lippery feel and were completely protected
against contamination by the molds Aspergillus niger and Eupeni-
cillium levitum in a 6 months challenge test.
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EXAMPLE 2
An aqueous composition according to the invention
was prepared identical to the composition of Example 1 except
that poly[oxyethylene(dimethyliminio)ethylene(dimethyliminio)ethy-
lene dichloridel (commercially available under the tradenameWSCP from ~uckman Laboratories Inc. - see description hereinbe-
fore) was employed on a weight for weight active basis in~tead
of Coemocil CQ.
Moistened wipes were.prepared employing the aqueou~
composition of Example 2 as impregnant using the identical
substrate and gravity application procedure described hereinbe^
fore for the preparation of the moistened wipes impregnated
with the composition of Example 1. These wipes also were
quite acceptable with respect to slippery feel.
Seven aqueous compositions were prepared which were
identical to the aqueous compo~ition of Example 1 with the
exception that on a weight for weight active basis one of
the following seven commercially available biocides was employ-
ed instead of Cosmocil CQ:
Composition A: N-alkyl~50% C14, 40% C12, 10% C16,) dimethyl
benzyl ammonium chloride
Compos~ on B: Cetyl pyridinium chloride
Compos_ _on C: Didecyl dimethyl ammonium chloride
Compos_ _on D~ {ydroxyethyl-l-benzyl-2-alkyl~coco)imidazolini-
um chlor de
Composition E: Diisobutylphenoxyethoxyethyl dimethyl benzyl
ammonium chloride
Composition F: Poly(dimethyl butenyl ammonium chloride)lq,
~-bis-triethanolammonium chloride
Composition G: Quaternium-33 which conforin~ to the formula:
1 334320
. -14-
CH2CH3
RCO-NH-(CH2)3 - N- CH3 CH3CH20S03
_ CH3
where RCO- represent~ the lanolin acid radical.
Moistened wipes were prepared employing Compoeition
A to G above as impregnant using the identical substratQ and
gravlty procedure deecribed hereinbefore for the preparation
of the moistened wipes impregnated with the composition of
Example 1. In each case the moistened wipes obtained had
an unacceptable slippery feel which rendered them unsuitable
for marketing.
