Note: Descriptions are shown in the official language in which they were submitted.
CA 0224~628 1998-08-20
6806/DQ
DISPOSABLE PREMOISTENED WIPE HAV~NG OPACITY AGENT
FELD OF THE rNVENTION
The present invention relates to disposable premoistened wipes, and more
particularly to a disposable premoistened wipe incl~l~ing an opacifying agent.
BACKGROUND OF THE rNVENTION
Premoistened wipes are well known in the art. Such wipes are also referred to
as "wet wipes" and "towelettes." Premoistened wipes include a substrate, such as a
nonwoven web of fibers, which is wetted with a liquid composition prior to use.
Such premoistened wipes can be used for removal of a substance from a
surface or object which is animate or in~nim~te. For instance, premoistened wipes
can be used for human clean~ing and wiping, such as for anal cle~n~ing perineal
cle~n~ing genital cle~ ing and face and hand cle~n~ing
Premoistened wipes known in the art can include a substrate in the form of an
airlaid nonwoven web of fibers. The substrate can be formed by air laying a blend of
natural and synthetic fibers to form a fibrous web, spraying water on the web, and
then embossing the web. A latex binder can then be applied to the web, followed by
curing of the latex binder in an oven. The nonwoven web is then premoistened with
an aqueous liquid composition. An example of such a premoistened web is
cGl.lmel~ially available as "Palllpe~s Baby Fresh" brand baby wipes marketed by The
Procter & Gamble Company of Cin~inn~ti~ Ohio.
The following patents di~close methods or appa~al-ls for forming webs: U.S.
Patent 3,862,472 issued Jan. 28, 1975 to Norton et al.; U.S. Patent 3,918,126,
issued Nov. 11, 1975 to Wood; U.S. Patent 3,982,302 issued Sept. 28, 1976 to
Vaalburg; U.S. Patent 4,004,323 issued Jan. 25, 1977 to Gotchel et al.; U.S. Patent
4,014,635 issued March 29, 1977 to Kroyer; U.S. Patent 4,064,600 issued Dec. 27,1977 to Gotchel et al.; U.S. Patent 4,074,393 issued Feb. 21, 1978 to Hicklin et al.;
CA 02245628 1998-08-20
U.S. Patent 4,097,965 issued July 4, 1978 to Gotchel et al.; U.S. patent 4,130,915
issued Dec. 26, 1978 to Gotchel et al.; U.S. Patent 4,144,619 issued March 20,
1979 to ~Vhite et al.; U.S. Patent 4,176,426 issued Dec. 4, 1979; U.S. Patent
4,207,367 issued June 10, 1980 to Baker; U.S. Patent 4,315,347 issued Feb. 16,
1982 to Austin et al.; U.S. Patent 4,640,810 issued Feb. 3,1987 to Laursen et al..
One object of the present invention is to provide a premoistened wipe having
improved opacity.
Another object of the present invention is to increase the opacity of a
premoistened wipe having a substrate comprising at least 50 percent by weight
cellulosic fibers.
Another object of the present invention is to provide a method for
incorporating an opacifying agent in a nonwoven web of fibers.
SUMMARY OF THE INVENTION
Applicant has recognized that one problem with premoistened wipes is that the
liquid composition with which the substrate is i...p. egl-~ted can reduce the opacity of
the wipe. Reduction of opacity on wetting is undesirable because end users of
premoistened wipes may perceive a relatively low opacity as indicating a thin, or low
quality wipe.
Reduction in opacity due to wetting is especially a problem in those cases
where the wipe substrate comprises a s~lbst~nti~l amount of cellulosic fibers. The
wet opacity of the wipe substrate could be improved by red~lc.ing the amount of
cellulosic fibers in the substrate, and in their place substituting relatively fine denier
synthetic fibers. However, such a substitution is undesirable from a cost standpoint.
Further, it can be desirable from an ecological standpoint to use natural fibers, such
as cellulosic fibers, so that at least portions of the substrate are more biodegradeable
relative to all synthetic compositions.
The present invention provides a premoistened wipe having improved wet
opacity. Accoldillg to one aspect of the invention, a premoistened wipe is provided
comprising an airlaid substrate imp~llaled with an aqueous liquid composition,
wherein the premoistened wipe has an average normalized wet opacity of at least
about 66, more preferably at least about 68, still more prererably at least about 70,
and even more pler~l~bly at least about 71. The average normalized wet opacity is
CA 0224~628 1998-08-20
determined based on measured values of opacity of the premoistened wipe, liquid
loading of the premoistened wipe, and basis weight of the dry substrate, as described
below.
The premoistened wipe of the present invention can have an average liquid
loading of at least 1.0 grams, more preferably at least about 1.5 grams, still more
preferably at least about 2.0 grams, and even more preferably at least about 2.5grams per gram of dry substrate. In one embodiment, the premoistened wipe has anaverage liquid loading of at least about 3.0 grams of liquid composition per gram of
dry substrate.
Further, the substrate can have a dry density of less than about 0.10 grams
per cubic centimeter, and more preferably less than about 0.075 grams per cubic
centimeter. Accordingly, the present invention provides a relatively high opacity
with the use of a relatively high liquid loading and a relatively low density substrate.
The premoistened wipe can have a substrate comprising a nonwoven web of
fibers. The nonwoven web can have a dry basis weight of at least 40 grams/squaremeter, and the basis weight can be between about 40 and about 80 grams/square
meter. The nonwoven web can comprise at least about 50 percent, and in one
embodiment at least about 70 percent by dry weight cellulosic fibers. The nonwoven
web can also include staple length synthetic fibers having a denier greater than about
1.0 gram/9000 meter of fiber length.
In one embodiment, the premoistened wipe includçs a plurality of embossed
regions dispersed throughout a background region of the nonwoven web, wherein
the embossed regions are relatively less opaque than the background region.
According to another aspect of the present invention, a prçmoistçned wipe is
provided having an airlaid nonwoven web ill.pregn~ted with an aqueous liquid
composition, wherein the nonwoven web inrl~ldçs an opacifying agent. The
opacifying agent can have an index of refraction greater than that of water (about
1.33), and more p-ere-ably has an index of refraction greater than that of cellulose
(about 1.53). In one embodiment of the present invention, the opacifying agent has
an index of refraction greater than about 1.40, more preferably greater than about
1.60, and even more preferably greater than about 2.00.
In one embodiment, the opacifying agent comprises a white pigment. In a
prere--ed embodiment, the opacifying agent conlp.;ges tit~rlium dioxide. The
CA 0224~628 1998-08-20
nonwoven web can comprise between about 0.3 percent and about 1.0 percent by
dry weight titanium dioxide.
According to another aspect of the present invention, a method for forming a
nonwoven web is provided. The method includes the steps of forming an airlaid web
of fibers; and adding an opacifying agent comprising titanium dioxide to the airlaid
web of fibers. The method can include the step of forming an airlaid web of fibers
comprising at least 50 percent, and more particularly at least 70 percent, by dry
weight cellulosic fibers.
In one embodiment, the method comprises the steps of wetting the web,
followed by embossing the web, followed by applying an adhesive binder
composition to the web, wherein the binder comprises titanium dioxide.
Surprisingly, the addition of the opacifying agent to the binder according to
the present invention improves the wet opacity of the background region of the
premoistened wipe, yet the difference in opacity between embossed regions and the
background region is not lost. Accordingly, the present invention provides the
benefit of improved wet opacity while m~int~ining the visual /lictinctiveness of an
embossed pattern.
BRIEF DESCRIPTION OF THE DRAWINGS
While the Specification concludes with claims particularly pointing out and
~i.ctinctly rl~imin~ the present invention, it is believed that the same will be better
understood by the following Specification taken in conjunction with the associated
drawings in which like components are given the same reference numeral, and:
Figure 1 is a photograph of a digital image of two premoistened wipes
positioned on a black background. The wipe designated by numeral 20 in Figure 1
comprises tit~nium dioxide acco.ding to the present invention, while the wipe
dçcign~ted by numeral 21 does not include titanium dioxide.
Figure 2 is a photograph, with back lighting of an enlarged portion of a
prçmoi.ct~ned wipe according to the present invention and having embossed regions
which are relatively less opaque than a background region.
Figure 3 is a scl..,.,.alic illustration of a premoiseened wipe having embossed
regions.
CA 0224~628 1998-08-20
Figure 4 is a schematic illustration of a process for forming an airlaid web of
fibers according to the present invention.
Figure 5 is an enlarged schematic illustration of the airlaying apparatus shown
in Figure 4.
DETAILED DESCRIPTION OF THE INVENTION
The premoistened wipe of the present invention comprises a substrate wetted
with a liquid composition. The premoistened wipe has an average normalized wet
opacity of at least about 66, more prefel ~bly at least about 68, still more preferably at
least about 70, and even more preferably at least about 71.
The term "liquid composition" includes any composition inclu~ling a liquid
phase, including but not limited to emulsions having a liquid phase.
The average normalized wet opacity is calculated based on measured values of
opacity of the premoistened wipe, liquid loading of the premoistened wipe, and basis
weight of the dry substrate. The procedure for measuring the opacity, and the
method of calculating the average normalized wet opacity, are described below in"Test Methods."
In a p[erel,ed embodiment of the present invention, the premoistened wipe
comprises a nonwoven substrate, the substrate inchl~ing an opacifying agent. Theopacifying agent can have an index of refraction greater than that of water (about
1.33), and more preferably has an index of refraction greater than that of cellulose
(about 1.53). In one embodiment of the present invention, the opacifying agent has
an index of refraction greater than about 1.40, more preferably greater than about
1.60, and even more preferably greater than about 2.00.
In one embodiment~ the opacifying agent comprises a white pigment. In a
p-efe"ed embodiment, the opacifying agent comprises tit~nillm dioxide. The
nonwoven web can comprise tit~nhlm dioxide, ~n~t~ç, tit~nillrn dioxide, rutile, or a
colllbinalion thereof.
The nonwoven web can comprise at least about 0.3 percent, and more
preferably at least about 0.5 percent by dry weight titanium dioxide. The nonwoven
web can comprise between about 0.3 percent and about 1.0 percent by dry weight
tit~n;~m dioxide.
CA 0224~628 1998-08-20
Other suitable opacifying agents include, but are not limited to clay, calcium
carbonate, zinc oxide, and diatomaceous silica.
The premoistened wipe has an average liquid loading of at least 1.0 grams,
more preferably at least about 1.5 grams, still more preferably at least about 2.0
grams, and even more preferably at least about 2.5 grams per gram of dry substrate.
In one embodiment, the premoistened wipe has an average liquid loading of at least
about 3.0 grams of liquid composition per gram of dry substrate.
The substrate can have a dry density of less than about 0.10 grams per cubic
centimeter, and more particularly, the substrate can have a dry density of less than
about 0.075 grams per cubic centimet~r. Accordingly, the present invention provides
a desirable level of opacity in a premoistened wipe having a relatively high liquid
loading level and a relatively low density.
The dry substrate can be wetted with an aqueous liquid composition (at least
50 percent by weight water). The liquid composition can include a number of
ingredients in addition to water, includin~ but not limited to preservatives,
surfA.,~tAnt.~, emollients, moisturizers (incl~ ing but not limited to hllmect~nts and skin
conditioning agents), fragrances, and fragrance solubilizers, as well as other
ingredients. The liquid composition is preferably at least 85 percent by weight water.
The dry substrate can be premoistened with about 1.5 grams to about 4.5 grams ofthe liquid composition per gram of the dry substrate, and in one embodiment,
between about 2.5 and 3.5 grams of liquid composition per gram of dry substrate.
Preferably, the substrate is premoistened with a liquid composition
comprising at least 85 percent by weight water and an effective amount of a
surfactant, an effective amount of an emollient, an effective amount of preservative,
an effective amount of a hll-~.e~ilA.)~ an effective amount of a fragrance, and an
effective amount of a fragrance solubilizer.
In one embodiment, the liquid composition includes at least about 95 percent
by weight water. The liquid composition can also include about 0.5-5.0 percent by
weight Propylene Glycol, which can serve as an emollient and hul.,c~,lanl, about 0.1-
3.0 percent by weight PEG-75 T.~Anolin, which can serve as an emollient; about 0.1-
3.0 percent by weight Coco~rnphodi~cet~te, which can serve as a surfactant for
cle~An~ing the skin; about 0.1-3.0 percent by weight Polysorbate 20, which can serve
as a surfactant for cleAr~ . the skin and as an emulsifier for solubilizing fragrance
co,npone"t~, about 0.01-0.3 percent by weight Methylparaben, which can serve as a
CA 0224~628 1998-08-20
preservative; about 0.005-0.10 percent by weight Propylparaben, which can serve as
a preservative; about 0.005-0.10 percent by weight 2-Bromo-2-Nitropropane-1, 3-
Diol, which can serve as a preservative; and about 0.02-1.0 percent by weight of a
fragrance component.
Other liquid compositions with which the substrate can be moistened are
described in the following patent doc~ nts which are incorporated herein by
reference: U.S. Patent 4,941,995 issued July 17, 1990 to Richards et al.; U.S. Patent
4,904,524 issued February 27, 1990 to Yoh; U.S. Patent 4,772,501 issued
September 20, 1988 to Johnson et al..
The substrate can comprise fibers and/or filamentary material, and can be
formed from woven materials, nonwoven materials, paper webs, or the like.
Particularly prèÇe. l ed materials are nonwoven webs having fibers or filaments
distributed randomly as in "airlaying" or certain "wet laying" processes, or with a
degree of orientation, as in certain "wet laying" and "carding" processes.
The fibers or filaments of the substrate can be natural, or of natural origin (e.g.
cellulosic fibers such as wood pulp fibers, cotton, and rayon fibers) or synthetic (e.g.
polyolefins, polyamides or polyesters), or combinations of natural and syntheticfibers.
In one embodiment ofthe present invention, the substrate comprises at least 50
percent by dry fiber weight cellulosic fibers. More particularly, the substrate can
comprise at least 70 percent by dry weight cellulosic fibers. The substrate can also
comprise synthetic fibers having a denier greater than about 1.0 grams per 9000
meters of fiber length, and the fibers having staple length of less than 1.0 inch.
Accordingly, the present invention provides a desirable level of wet opacity in a
prçn ~ictçned wipe having a substrate comprising a relatively high level of cellulosic
fibers. Further, a desirable level of wet opacity is achieved without the use ofrelatively fine, relatively low denier synthetic fibers.
Moreover, the present invention can provide a desirable level of wet opacity
using relatively high density synthetic fibers. Generally, for a given denier and a
given basis weight, a web formed from synthetic fibers made of a relatively highdensity material will include less of the synthetic fibers per unit area than will a web
formed from synthetic fibers made of a relatively lower density material.
Accordingly, the use of synthetic fibers having a relatively high density would be
CA 0224~628 1998-08-20
expected to result in a relatively low opacity as compared to the opacity achievable
with synthetic fibers having a relatively low density.
The present invention can provide a desirable level of wet opacity in a
premoistened wipe having a substrate including synthetic fibers having a densitygreater than 1.0 gram per cubic centimeter. In particular, the present invention can
provide a desirable level of wet opacity in a premoistened wipe comprising polyester
fibers, polyester fibers having a density of about 1.38 grams per cubic centimeter. In
comparison, polypropylene fibers have a density between about 0.90 and about 0.96
grams per cubic centimeter.
According to one pl e~ l ed embodiment of the present invention, the
premoistened wipe comprises an airlaid nonwoven web comprising at least about 70percent by dry weight cellulosic fibers, less than 20 percent by weight synthetic
fibers, and at least 5 percent by dry weight of an adhesive binder. In one pr~rell~d
embodiment, the opacifying agent is added to the adhesive binder.
A premoistened wipe according to the present invention can comprise an
airlaid nonwoven web comprising, based on dry substrate weight, between about 70percent and about 80 percent by weight cellulosic fibers, between about 10 percent
and about 15 percent by weight polyester fibers, and between about 10 percent and
about 20 percent by weight adhesive binder. The adhesive binder can comprise a
latex (styrene butadiene) adhesive. The adhesive binder can include an opacifying
agent such as titanium dioxide in the amount equal to at least about 2 percent, more
preferably at least about 4 percent of the latex solids weight, and still more preferably
at least about 5 percent of the latex solids weight.
Figure 1 is a photograph of a digital image of a premoistened wipe dçsign~ted
by the numeral 20, the wipe 20 comprising tit~nil~m dioxide according to the present
invention. Figure 1 also shows a second premoistened wipe d~ci~?ted by numeral
21, the wipe 21 having generally the same fiber composition, basis weight, liquid
loading as the wipe 20, but the wipe 21 not including tit~ni~m dioxide. The wipes
in Figure 1 are embossed and have a background and visually disting~ h~ble
embossed regions which are relatively less opaque than the background.
The image in Figure 1 was prepared by placing the premoistened wipes on a
AGFA Arcus II Color Scanner and covered with a piece of exposed x-ray film. The
x-ray film provides a uniform opaque black background for the samples. The samples
were sc~ ed using the AGFA FotoLook v2.09 plugin for Adobe Photoshop 4.0
CA 0224~628 1998-08-20
running on a Dell Dimension ~S-266 personal computer. The FotoLook plugin was
set to scan in 8 bit gray scale at 300dpi and the grayscale calibration was set to
Automatic. The resulting image was read directly into Photoshop and saved as a
TIFF format image. The Adjust tool in Photoshop was used to increase the contrast
and reduce the brightness prior to printing.
Figure 2 is a photograph of a premoistened wipe 20 according to the present
invention, the photograph made with back lighting. Figure 2 illustrates embossedregions which are relatively less opaque than the background region.
Figure 3 is a schematic illustration of a wipe according to the present
invention, the wipe is dçsign~ted generally by numeral 20, the background is
design~ted generally by numeral 30, and the embossed regions are de~i~n~ted
generally by reference numeral 40.
Method of Making Nonwoven Web:
The premoistened wipe of the present invention can have an airlaid nonwoven
web made according to the following method.
A source of pulp fibers, such as pulp drylap in roll form, is provided. A
separate source of synthetic fibers, such as bales of polyester fibers, is provided.
The rolled pulp is unwound, and pulp fibers are individu~ ed by a series of
h~n mermills, as is known in the art. The individu~li7ed pulp fibers are consolidated
to form a mat of pulp fibers. The mat is humidified to have a moisture level of
b~;l..cen about 11 and 13 percent (11 to 13 grams of water per 100 grams of dry
fiber). The pulp mat is d~sign~ted 100 in Figure 4, and is shown being carried on a
conveyor 110 toward a web airlaying apparalLls 300.
Separately, the baled synthetic fibers are individ~ ed to provide a mat of
synthetic fibers. The fibers can be individu~li7ed in any suitable manner known in the
art, such as by progressively opening fiber bundles in stages. Referring to Figures 4
and 5, the mat of synthetic fibers is design~ted 200 in Figure 4, and is shown being
carried on a conveyor 210 toward the web airlaying appa~alus 300.
The mat 100 enters the web airlaying apparatus 300 through a nosebar 120,
roller 130 arrangement, and the mat 200 enters the apparatus 300 through a nosebar
CA 0224S628 1998-08-20
220 and roller 230 arrangement. The nosebar/roller arrangements provide even
metering of the mats.
The airlaying appa,dllls 300 includes a housing 310 and a rotating element 320
disposed within the housing 310. The apparatus 300 also includes a source of
pressurized air, the pressurized air being designated 360 in Figure 4. The rotating
element has a toothed surface which aids in carrying the fibers from the mats 100 and
200 and injecting the fibers from the mats 100 and 200 into the pressurized air 360
so that the fibers are entrained in and generally unformily mixed by the air 360.
A vacuum device 400 is associated with an air pervious forming screen 410.
The vacuum device 400 draws the mixed fibers provided by the airlaying apparatus300 onto the forming screen 410 to provide an airlaid web 500 comprising the pulp
fibers and the polyester fibers, the web having a basis weight of about 50-60 grams
per square meter.
While the app~ s 300 is shown for providing the airlaid web 500, it will be
understood that other airlaying techniques can be used to provide an airlaid web 500,
as are known in the art. The following patents are incorporated herein by reference
for the purpose of disclosing airlaying methods and/or appa.~ s: U.S. Patent
3,862,472 issued Jan. 28, 1975 to Norton et al.; U.S. Patent 3,918,126, issued Nov.
11, 1975 to Wood; U.S. Patent 3,982,302 issued Sept. 28, 1976 to Vaalburg; U.S.
Patent 4,004,323 issued Jan. 25, 1977 to Gotchel et al.; U.S. Patent 4,014,635
issued March 29, 1977 to Kroyer; U.S. Patent 4,064,600 issued Dec. 27, 1977 to
Gotchel et al.; U.S. Patent 4,074,393 issued Feb. 21, 1978 to Hicklin et al.; U.S.
Patent 4,097,965 issued July 4, 1978 to Gotchel et al.; U.S. patent 4,130,915 issued
Dec. 26, 1978 to Gotchel et al.; U.S. Patent 4,144,619 issued March 20, 1979 to
White et al.; U.S. Patent 4,176,426 issued Dec. 4, 1979; U.S. Patent 4,207,367
issued June 10, 1980 to Baker; U.S. Patent 4,315,347 issued Feb. 16, 1982 to
Austin et al.; U.S. Patent 4,640,B10 issued Feb. 3, 1987 to Laursen et al., and Re.
31,775 reissued Dec. 25, 1984.
The airlaid web 500 is carried through a nip formed between rolls 610 and 620
to provide low level consolidation of the web 500. A vacuum l,~r roll 640 is
then used to transfer the web 500 from the forming wire 410 to a conveyor 710.
The web 500 is wetted while being carried on conveyor 710. A plurality of
nozzles desigr~ted 730 direct water on to the upper surface of the web 500 to
provide wetting of the web 500. The amount of water added should be adjusted to
CA 0224~628 1998-08-20
an effective level in order to preserve the clarity of the emboss pattern. Preferably, at
least about 0.25 gram per gram of fiber weight, more preferably at least about 0.28
gram per gram of fiber weight should be added to the web of fibers. Applicant has
found that for the above described mixture of cellulosic and polyester fibers, awetting level of less than about 0.22 gram/ gram can result in loss of clarity of the
web emboss pattern when an opacifying agent is used. Without being limited by
theory, it is believed that wetting in an amount of at least 0.25 gram per gram and
more preferably at least about 0.28 gram per gram of fiber weight helps to ensure
clarity of the web emboss pattern when an opacifying agent is added to the web.
The wetted web 500 is next carried through an embossing nip formed between
a rubber anvil roll 740 and a steel pattern roll 742. The rubber anvil roll 740 has a
P&J hardness of about 17.5. The steel pattern roll can have a land area
(corresponding to the embossments formed in the web) which is between about 12
and about 20 percent of the surface of the pattern roll. The nip load should be
adjusted to an effective level for m~int~inine clarity ofthe emboss pattern. For a land
area of about 12 percent, it is believed that the emboss nip should provide a nip
loading of at least about 300 pli, corresponding to a nip pressure of at least about
2500 psi, and more preferably a nip loading of at least about 360 pli corresponding to
a nip pressure of at least about 3000 psi. It has been found that below a nip loading
of about 250 pli and nip pressure of about 2300 psi, clarity of emboss pattern suffers
when an opacifying agent is added to the web.
The embossed web is llansrelled from the anvil roll 740 to a conveyor 810A,
followed by llansrer to a conveyor 810B. The embossed web 510 is then transferred
to a conveyor 812 to have a first face of the embossed web 510 (the face of the web
positioned against roll 742 during embossing) facing outwardly. The first face of the
embossed web 510 is sprayed with a binder adhesive composition co~ g the
opacifying agent. The binder adhesive is provided by a plurality of nozzles indicated
by I ~r~;r."~ce numeral 820 in Figure 4.
The web 510 is then ll ~--sre. l ed to a conveyor 814 such that the second face of
the embossed web faces outwardly. A second plurality of nozzles indicated by
reference numeral 830 is used to spray an binder adhesive co.~ ;n;~g the opacifying
agent onto the second face of the embossed web. In a prerelled embodiment, the
opacifying agent co...p-;ses t ~- ~m dioxide, and the binder adhesive composition
comprises latex and at least about 2 grams, more preferably at least about 4 grams,
CA 0224~628 1998-08-20
- 12
and even more preferably at least about 5 grams of titanium dioxide solids per 100
grams of latex adhesive solids.
The embossed web 510 is then carried through drying ovens 900 to dry the
web and to cure the binder adhesive.
EXAMPLE:
According to one exemplary embodiment, a premoistened wipe according to
the present invention comprises an airlaid nonwoven web wetted with an aqueous
liquid composition comprising about 97 percent by weight water. The balance of
the liquid composition comprises Propylene Glycol, PEG-75 Lanolin,
Cocoampho~ .et~te, Polysorbate 20, Methylparaben, Propylparaben, 2-Bromo-2-
Nitropropane-l, 3-Diol, and fragrance.
The nonwoven web comprises about 73.S percent by dry weight cellulosic
fibers (Southern softwood Kraft having an average fiber length of about 2.6 mm);about 10.5 percent by dry weight polyester fibers having a denier of about 1.35 and a
staple length of about 0.85 inch; and about 16 percent by dry weight adhesive binder
solids, the adhesive binder solids including titanium dioxide. The basis weight of the
substrate is about 64 grams per square meter. and the density of the substrate prior
to lotionizing (wetting) with the liquid composition is about 0.054 grams per cubic
clontimeter,
The airlaid web is wetted and embossed prior to application of the adhesive
binder. The airlaid web is wetted with about 0.28 grams of water per gram of dryfiber weight prior to embossing. The wetted web is then embossed with a patterning
roll having a land area of about 12 percent, and with a nip loading of about 360 pli
and a nip pressure of about 3000 psi. The binder adhesive is then sprayed on theboth surfaces of the web in an amount sufficient to provide a dry nonwoven web
having about 16 percent by dry weight binder adhesive solids. The web has a basis
weight of about 63.6 grams per square meter.
The adhesive binder solids comprise primarily latex (styrene-but~diene) solids.
The adhesive binder solids also include Cymel 303 (m~l~mine formaldehyde)
(available from American Cyanamid of Wayne, NJ) in the amount of about 6 percentby weight of the latex solids; Aerosol GPG (dioctyl sulfos~lcin~te) (available from
American Cyanamid) in the amount of about 4.3 percent by weight of the latex
solids; ammonium chloride in the amount of about 1.35 percent by weight of the
CA 0224~628 1998-08-20
latex solids; and titanium dioxide in the amount of about 5 percent by weight of the
latex solids.
The adhesive binder is made according to the following procedure. About
22,500 pounds of Rovene 5550 (49 percent solids styrene butadiene) latex adhesive
available from Mallard Creek Polymers of Charlotte, N.C. is introduced into an
adhesive mix tank. Separately, about 716 pounds of a slurry of water and titanium
dioxide solids (about 77 percent by weight titanium dioxide solids) is provided. The
slurry is conll"crcially available from the Kemira Pigment~, Inc. of Savannah, GA
under the cornmercial design~tion UDR-606. The titanium dioxide slurry and about5000 pounds of cold water are mixed together in a mix tank for 30 min~ltes, and then
added to the Rovene 5550 in the adhesive mix tank. This mixture of cold water,
titanium dioxide slurry, and Rovene 5550 is constantly agitated in the adhesive mix
tank.
Separately, 5000 pounds of hot water are introduced into a chemical mix tank.
About 677 pounds of Aerosel GPG (70 percent solids) and about 668 pounds of
Cymel 303 (99 percent solids) are added to the hot water, and this mixture is agit~ted
for 45 minutes. After 45 minutes, the mixture of hot water, Aerosel GPG, and
Cyrnel 303 is added to the latex/titanium dioxide mixture in the adhesive mix tank
and the mixture in the adhesive rnix tank is constantly ~git~ted
Then, 5000 pounds of cold water and about 150 pounds of ammonium
chloride are added to the chemical mix tank and the mixture in the chemical mix tank
is agitated for 45 minl~tçs The mixture in the chemical mix tank is then added to the
mixture in the adhesive mix tank, and the resulting liquid adhesive binder mixture in
the adhesive mix tank is agitated for one hour before application to the web.
Prior to application to the web, the liquid adhesive binder mixture is diluted
with water to bclv~eell about 21 percent and about 25 percent total solids.
The web is premoistened with an aqueous liquid composition COlllpl ising about
97% by weight water.
The resl-lting premoistened wipe has an average liquid loading of 3.08 grams
per gram (Saturation percclllage of 308 percent), and an average normalized opacity
of 72.2.
CA 0224~628 1998-08-20
TEST METHODS:
BASIS WEIGHT:
The basis weight of the substrate is the weight of the dry substrate per unit
area, and can be expressed in grams per square meter of dry substrate.
CALIPER:
The caliper of the dry substrate is measured with a circular load foot having anarea of about 2 square inches and which provides a conrllling pressure of about 95
grams per square inch. The caliper is measured prior to lotionizing the dry substrate
with the liquid composition.
DENSITY:
The density of the dry substrate is obtained by dividing the basis weight by thecaliper, using consistent units. The density is measured prior to lotionizing the dry
substrate with the liquid composition.
OPACITY:
The average normalized opacity is determined using the following procedure.
Opacity measule",enls are made using a Technidyne Model BNL-3 Opacimeter
m~nuf~ct~lred by the Technidyne Col~,oralion of New Albany, Tntli~n~ which
opaçim~otçr conforms to TAPPI Test Method T425 om-9 1. The opacimçter provides
an opacity reading which is a nondimensional ratio of the amount of light reflected
from a sample when the sample is backed by a black body to the amount of light
reflected from the sample when the sample is backed by a white body.
The opacimeter includes a standard black bacl~ing a standard white backing,
an ins~ndeccçnt light source, an infrared absorbing filter, a photocell, and an
integrating cavity.
The opacimeter is allowed to warrn up for at least 20 minl1tçc and is calibratedwith opal glass opacity standards.
The opacity values are determined for premoistened s&"")les. The sample is
placed on the opacimçtçr so that the opacity measu, ~ ent~ are taken in the
CA 0224~628 1998-08-20
background (nonembossed) portion of the premoistened wipe, if possible. If it is not
possible to avoid embossed portions while taking the measurements, the opacity
measurements should be taken in the portion of the substrate having the least amount
of embossing. The sample is first backed with the standard white backing, to provide
an instrument reading of 100. The white backing is then replaced with the black
backing, and the instrument meter provides the contrast ratio. This contrast ratio,
expressed as a percentage between 1-100 percent, is the opacity value for the
sample.
Sampling: The opacity values are determined for premoistened samples. In
order to account for differences in lotion loading within a package of premoistened
wipes, at least ten samples from two separate packages (e. g., tub, bottle, refill pack)
are measured to provide a total of at least 20 opacity measurements (10 from each of
two packages.) The average of these measurements provides the "average opacity
value."
If the premoistened wipes are packaged in recognizable groups, at least one
sample should be measured from each recognizable group within the package. For
instance, premoistened wipes pack~eçd in tub type containers may be grouped in
identifi~ble "clips" col-~sl)onding to grouping of the wipes during converting and
p?~c~ging By way of example, if a tub of wipes has 16 clips of 6 wipes (96 total),
then at least one wipe from each of the 16 clips should be measured. If a tub ofwipes has 10 clips of 8 wipes (80 wipes total), then at least one wipe from each of
the 10 clips should be measured.
For each of the samples measured for opacity, the wet sample weight and dry
sample weight is also measured so that the liquid loading (grams liquid
composition/gram dry substrate) can be determined. The dry sample weight can be
determined by weighing the sample prior to adding the liquid composition to the
substrate, or alternatively, by evaporating the liquid composition from the substrate.
The average of the liquid loading values for the samples provides the "average liquid
loading"
Normalized Opacity:
The average normalized opacity is determined from the average measured
opacity according to the following equation:
CA 0224~628 1998-08-20
A~O = AO +(AULL/0.27)+(0.544)$(63.6-B W)
where:
ANO is the Average Normalized wet opacity, a number between 1 and 100
AO is the Average wet opacity, a number between 1 and 100.
ALL is the Average liquid loading ( grams liquid/grams dry substrate)
BW is the basis weight in grams per square meter
For example, for an average saturation of 308 percent, a basis weight of 63.6 grams
per square meter, and an average opacity of 60.8, the average liquid loading is 3.08
and the average normalized wet opacity is
60.8 +(3.08/0.27)+(0.544)*(63.6-63.6)= 72.2.
COMPARATIVE DATA:
Tables 1, 2,3,4, and 5 list comparative opacity data. Table 1 provides data
for a premoistened wipes made according to the present invention, the premoistened
wipes comprising a substrate having an average basis weight of 63.6 grams per
square meter, the substrate comprising about 73.5 percent by dry weight cellulosic
fibers, about 10.5 percent by dry weight polyester fibers, and about 16 percent by dry
weight adhesive binder, and the adhesive binder composition comprising titiqnil~m
dioxide solids in the amount of about 5 percent of the weight of the latex solids in the
adhesive binder composition.
Table 2 provides data for premoistened wipes not inclu-lin~ titanium dioxide,
but otherwise having generally the same basis weight and fiber composition as the
wipes in Table 1. These premoistened wipes are commercially available as "Pa"lper~
Baby Fresh" brand baby wipes commercially available from The Procter and Gamble
Co.
Table 3 provides data for a premoistened wipes made according to the present
invention, the premoistened wipes comprising a substrate having a dry basis weight
of 713 grams per square meter, and the substrate con~p,is;ng about 73.5 percent by
dry weight cellulosic fibers, about 10.5 percent by dry weight polyester fibers, and
CA 0224~628 1998-08-20
about 16 percent by dry weight adhesive binder, and the adhesive binder composition
comprising titanium dioxide solids in the amount of about 5 percent of the weight of
the latex solids in the adhesive binder composition.
Table 4 provides data for premoistened wipes not including titanium dioxide,
but otherwise having generally the same basis weight and fiber composition as the
~vipes in Table 3.
Table 5 provides data for a commercially available premoistened wipe which
comprises a nonwoven web of meltblown polypropylene fibers and cellulosic fibers.
The tables include data for samples taken from two tub type p~el~ge~. The
average saturation listed in the tables is the average liquid loading multiplied by 100
and expressed as a percent.
Table 1: Basis Weight 63.6 gsm With TiO2
tub #1 tub #2
opacity sat% norm opopacity sat%normop
top 67.8 187% 74.72 69.6 187% 76.52
2 66.4 207% 74.08 64.2 207% 71.88
3 67.0 207% 74.68 64.7 228% 73.14
4 62.2 224% 70.49 61.5 224% 69.79
61.8 244% 70.85 64.2 240% 73.09
6 60.3 248% 69.50 61.3 261 %70.95
7 61.9 265% 71.71 61.1 257% 70.60
8 63.2 277% 73.46 61.4 302% 72.57
9 60.6 289% 71.32 58.6 302% 69.77
58.5 318% 70.28 56.1 310% 67.58
11 56.2 359% 69.50 59.8 351% 72.79
12 64.1 380% 78.16 59.7 359% 73.00
13 56.8 396% 71.46 55.1 416% 70.52
14 56.9 429% 72.78 57.8 429% 73.68
54.3 425% 70.03 60.8 445% 77.28
bottom55.1 420% 70.67 57.7 461% 74.79
average wet opacity 60.8
average saturation 308%
average basis weight 63.6
average normalized wet opacity 72.2
CA 02245628 1998-08-20
Table 2: Basis Weight 63.6 gsm Without TiO2
tub #1 tub #2
opacity sat% norm opopacity sat%nomm op
top 56.7 195% 63.93 56.3 199%63.68
2 58.8 199% 66.18 59.9 207%67.58
3 55.7 216% 63.68 54.5 179%61.12
4 57.5 240% 66.39 60.1 216%68.08
53.4 203% 60.93 59.0 248%68.20
6 56.3 228% 64.74 52.1 277%62.36
7 52.1 248% 61.30 52.2 277%62.46
8 56.0 281 % 66.41 53.9 289%64.62
9 58.6 314% 70.23 53.2 220%61.34
53.5 334% 65.89 53.2 355%66.35
11 54.7 359% 68.00 52.7 343%65.39
12 49.9 380% 63.96 54.1 375%68.00
13 47.4 375% 61.30 53.8 396%68.46
14 48.8 420% 64.37 47.4 416%62.82
55.3 412% 70.57 51.7 457%68.64
bottom48.7 441 % 65.03 48.7 449%65.34
average wet opacity 53.9
average saturation 305%
average basis weight 63.6
average norrnalized wet opacity 65.2
CA 0224~628 1998-08-20
Table 3. Basis Weight 71.3 gsm With TiO2
tub #1 tub #2
opacity sat% norm opopacity sat%norrn op
top 64.6 192% 67.52 65.5 181 %68.02
2 66.2 203% 69.53 64.2 210%67.80
3 64.0 214% 67.73 66.7 214%70.43
4 64.5 236% 69.04 61.6 228%65.87
S 64.9 228% 69.17 59.4 218%63.27
6 66.5 232% 70.91 65.3 269%71.06
7 66.3 276% 72.33 56.9 221 %60.90
8 68.3 276% 74.33 63.4 287%69.84
9 58.4 323% 66.19 61.9 309%69.15
67.3 345% 75.90 61.6 298%68.44
11 56.1 353% 64.97 57.0 345%65.60
12 61.5 378% 71.31 57.9 371%67.44
13 58.2 393% 68.56 57.1 389%67.32
14 58.5 455% 71.15 58.8 422%70.24
57.0 429% 68.71 52.1 407%63.00
bottom58.8 440% 70.91 52.2 440%64.31
average wet opacity 61.3
average saturation 306%
average basis weight 71.3
average norrnalized wet opacity 68.5
CA 0224~628 1998-08-20
Table 4: Basis Weight 71.3 gsm Without TiO2
tub #1 tub #2
opacity sat% norm opopacity sat%norm op
top 62.8 199% 65.99 58.8 199% 61.99
2 59.2 199% 62.39 62.5 218% 66.37
3 63.0 221 % 67.00 65.2 236% 69.74
4 56.1 221% 60.10 62.6 239% 67.28
62.8 228% 67.07 61.4 265% 67.02
6 64.1 250% 69.18 57.4 243% 62.21
7 60.5 265% 66.12 59.2 269% 64.96
8 61.5 294% 68.21 59.6 294% 66.31
9 59.5 312% 66.88 63.2 294% 69.91
58.3 316% 65.82 56.4 353% 65.27
11 59.1 371% 68.64 52.3 353% 61.17
12 54.6 367% 64.01 57.9 382% 67.85
13 56.4 389% 66.62 52.5 393% 62.86
14 50.6 400% 61.23 52.2 404% 62.96
53.2 411 % 64.23 51.2 429% 62.91
bottom53.4 436% 65.38 52.7 411 %63.73
average wet opacity 58.1
average saturation 308%
average basis weight 71.3
average normalized wet opacity 65.4
CA 0224~628 1998-08-20
21
Table 5: CG,.. er-,ially Available Product
Basis Weight 77.2 gsm
tub #1 tub #2
opacity sat% norrn op opacity sat%norm op
top 64.8 235~h 66.09 74.5 224%75.40
2 70.9 235% 72.19 73.4 235%74.69
3 73.5 245% 75.18 65.7 242%67.25
4 71.1 259% 73.30 62.7 252%64.64
66.9 266% 69.36 68.8 266%71.26
6 65.5 277% 68.35 61.1 284%64.21
7 67.2 294% 70.70 67.4 298%71.03
8 65.7 301% 69.46 65.1 319%69.52
9 S9.0 319% 63.42 66.7 330%71.51
bottom62.9 340% 68.10 65.4 368%71.64
average wet opacity 66.9
average saturation 279%
average basis weight 77.2
average norrnalized wet opacity 69.9
