[0001] Wiping articles made of natural chamois, a highly absorbent leather derived from
the hides of goat-like antelopes (e.g., from chamois) or other animals, are commonly
used in the polishing or drying of certain objects such as automobiles after washing.
The absorbent properties of natural chamois have also been emulated in "synthetic
chamois", and synthetic chamois articles or wiping articles are known and are commercially
available. These synthetic articles are formed, for example, by binding a nonwoven
web of fibers with a binder. The fibers may comprise, for example, polyvinyl alcohol
(PVA) -- based fibers bound together with a crosslinked PVA binder. Published PCT
Application WO 94/28223 describes highly absorbent wiping articles comprised of a
nonwoven web bonded with crosslinked PVA binder resins. Other known synthetic chamois
are made by bonding nonwoven fibers with an acrylic latex binder. Suitable acrylic
binders typically include functional groups to render both the binder and the finished
wiping article hydrophilic. Although these acrylic based wiping articles are comparatively
inexpensive to make, they often experience undesirably high drag when used in many
wiping applications.
[0002] Binders made with chemically crosslinked PVA provide some distinct advantages when
incorporated in a synthetic wipe. For example, PVA binders increase and improve the
properties of a dry wipe by providing a non-linting wipe surface, good mechanical
strength, and desired hydrophilic properties. Moreover, PVA binders may be cured in
the presence of colorants to generate colored wiping articles.
[0003] In the manufacture of synthetic chamois or wiping articles, coloration of the wipe
is generally desired for aesthetic reasons as well as for practical or functional
reasons. Certain colors, for example, are effective in hiding stains on the surface
of the wipe. Additionally, some countries have developed color coding systems for
consumer items, including wiping articles, wherein the color of the article designates
an intended area of use such as red for use in bathrooms, green for use in kitchens,
and the like. In the coloration of these articles, the use of pigments is generally
preferred over dyes because pigments offer greater resistance to fading in the presence
of cleaning chemicals.
[0004] Commercially available PVA based wiping articles are currently colored in pastel
shades achieved either by the addition of pigment or as a result of acid discoloration
during manufacture. The use of pigments to provide more vividly colored PVA based
wiping articles, however, has generally been unsuccessful because these wiping articles
have consistently experienced pigment loss, referred to as "color bleed", when the
wipe is exposed to water, especially in the presence of soaps or detergents.. The
color bleed phenomenon is attributed to the loss of certain pigment particles that
are not adequately retained by the binder resin, but are readily released during the
wringing or soaking of the wipe, especially in soapy water. The noticeable loss of
pigment from these articles is aesthetically undesirable, and the pigment lost from
the article may damage (e.g., stain) the surface being wiped. Although the color bleed
problem may be avoided by extensive washing of the wiping article prior to its packaging
and use, this additional preparation is costly and may damage the wipe. Consequently,
there is a need to solve the problem of color bleed in PVA based wiping articles by
providing a means for the retention of pigments in the wipe without prewashing the
article prior to use.
[0005] It is desirable to provide a solution to the foregoing problem and fill a longfelt
need by providing PVA based wiping articles with bright vivid colors. It is desirable
to provide these wiping articles by a coloration process utilizing pigments, resulting
in an article that does not experience noticeable color bleed when exposed to water,
including water containing soaps or detergents. It is also desirable to provide a
method for the manufacture of these wiping articles.
[0006] The present invention provides vividly colored absorbent articles particularly useful
as wiping articles and a method for their manufacture. The articles provide excellent
wiping performance, but experience no significant color bleed during use, even when
exposed to soapy water or the like.
[0007] In one aspect, this invention is an absorbent article comprising a substrate comprised
of organic fibers having a plurality of pendant hydroxyl groups; a binder coated on
at least a portion of the fibers, the binder comprising a crosslinked polyvinyl alcohol
and a hydrophobic polymer; and pigment distributed within the binder. Preferably,
the substrate is a nonwoven web of organic fibers selected from the group of rayon
and polyvinyl alcohol. The polyvinyl alcohol (PVA) polymer may be derived from partially
or completely hydrolyzed homopolymers and copolymers of vinyl acetate. Preferably,
the PVA polymer is a silanol modified PVA. The hydrophobic polymer is derived from
a hydrophobic latex emulsion. Preferably, the hydrophobic polymer is a self-crosslinking
polymer. The pigment is preferably an organic pigment.
[0008] As used herein, the term "absorbent" refers to the ability of a material to absorb
a liquid (e.g., water) and to retain the liquid until it is forced out; it also refers
to the ability of a material to wet out quickly when exposed to a liquid. "Substrate"
refers to a woven, knitted, or nonwoven material. "Fiber" refers to a threadlike structure
(In referring to the fibers of webs used to make the articles herein, "linear density"
or "fineness" refers to the weight in grams for a given length of a single fiber.).
"Crosslinking" refers to chemical reactions of monomers, prepolymers, or polymers
(present, for example, in the binder precursor) in which linkages are formed between
polymer chains. "Self-crosslinking" refers to a polymer derived from reactants (e.g.,
monomers), a prepolymer or a polymer that is capable of undergoing a crosslinking
reaction without the addition of crosslinking agents. "Pigment" refers to an insoluble
material (i.e., a coloring agent) suspended in a medium.
[0009] In another aspect, this invention is a method of making an absorbent article, the
method by providing a substrate comprising organic fibers having a plurality of pendant
hydroxyl groups; coating at least a portion of the fibers with a mixture of a pigment
and a binder precursor, the binder precursor comprising polyvinyl alcohol and a hydrophobic
latex emulsion; and curing the binder precursor to provide an absorbent article.
[0010] In yet another aspect, this invention is an absorbent article comprising a substrate
having first and second major surfaces, the substrate comprising organic fibers having
a plurality of pendant hydroxyl groups, wherein at least one of the first and second
major surfaces is coated with a mixture of a binder comprising a crosslinked polyvinyl
alcohol and a hydrophobic polymer and pigment distributed within the binder.
[0011] In describing the details of the preferred embodiment, reference is made to the various
Figures, wherein:
Figure 1 is a perspective view of a wiping article made in accordance with the invention;
Figure 2 is a cross-section along the lines 2-2 of the article of Figure 1; and
Figure 3 is a schematic diagram of a preferred method of making articles of the invention.
[0012] The articles of this invention preferably are comprised of substrates comprising
organic fibers having a plurality of pendant hydroxyl groups, wherein at least a portion
of the fibers are coated with a mixture of pigment and binder. A mixture of PVA and
hydrophobic latex emulsion forms a binder precursor which is cured to form the binder
of the invention. The PVA crosslinks due to the presence of a crosslinking agent.
The hydrophobic latex emulsion is preferably a self-crosslinking latex, which means
that a crosslinking agent is not needed. Surprisingly, the combination of the crosslinked
PVA and the hydrophobic polymer derived from the hydrophobic latex emulsion produces
a binder that will retain pigment within the finished wiping article, maintain the
color of the finished article, and prevent color bleed.
[0013] The substrate of this invention may be a woven or nonwoven material. Woven materials
include fabrics made by weaving and knitting. Nonwoven materials typically are referred
to as mats or webs and are formed by techniques including stitchbonding, air laying,
carding, spin bonding, melt blowing, and wet laying.
[0014] Preferably, the substrate of this invention is a nonwoven web. More preferably, the
nonwoven web has entangled fibers. Entangled fibers are produced by methods such as
hydroentangling and needletacking.
[0015] The substrate typically will have a thickness ranging from about 0.25 to 2.54 mm
(10 to 100 mils), preferably 0.76 to 1.78 mm (30 to 70 mils), more preferably 1.02
to 1.52 mm (40 to 60 mils). The weight per unit area of the substrate preferably ranges
from about 50 g/m
2 up to about 250 g/m
2. Woven or knitted webs can be produced to a desired thickness and basis weight. Nonwoven
webs can be produced by some techniques in very thin, lightweight layers. Preferred
thicknesses and basis weights for nonwoven webs may be achieved either by carding
and crosslapping operations or by air laying followed by fiber entanglement (e.g.,
hydroentanglement, needletacking and the like). Carded and crosslapped webs may also
be entangled. Carded and crosslapped webs are preferred for use in the articles of
the present invention.
[0016] Referring to the drawings, Figure 1 illustrates an absorbent wiping article 10 according
to the invention. Article 10 includes a nonwoven web made of a plurality of fibers
12 at least a portion of which are coated with a mixture of pigment and binder, as
is further described herein. As seen in Figure 2, the article 10 (illustrated in exaggerated
thickness) includes first and second major surfaces 14 and 16, respectively. Each
of surfaces 14 and 16 comprise a combination of calendered and fused binder coated
organic fibers. More nonwoven web makes up the middle portion 18 of the article 10.
Those skilled in the art will appreciate that an article can be prepared wherein only
one of the major surfaces (i.e., surface 14) is coated with binder. The uncoated surface
(i.e., surface 16) can be laminated, for example, to another article or a substrate
such as a sponge, urethane foam, or the like.
[0017] The nonwoven web may be made from any of a variety of hydrophilic fibers, and may
include a portion (e.g., less than about 50 percent) of hydrophobic fibers. Hydrophobic
fibers include polyolefin fibers such as polyester, polypropylene, and polyamide fibers.
Suitable hydrophilic fibers for use herein may be selected from the following fiber
types: cellulosic-type fibers such as PVA (including hydrolyzed copolymers of vinyl
esters, particularly hydrolyzed copolymers of vinyl acetate), cotton, viscose rayon,
cuprammonium rayon and the like; as well as thermoplastics such as polyesters, polypropylene,
polyethylene, nylons and the like. The preferred cellulosic-type fibers are rayon
and polyvinyl alcohol (PVA) and are commercially available as staple fibers. Suitable
rayon fibers are viscose rayon staple fibers commercially available from Courtaulds
Fibers Inc. of Axis, AL, under the designations 18552 and T2222. Other suitable rayon
fibers are commercially available from Courtaulds Fibers, Inc. under the trade designation
"Lyocell" and "Tencel". Suitable PVA fibers include those available under the trade
designations VPB 152 and VPB 174 from Kuraray Co. of Tokyo, Japan.
[0018] Nonwoven webs containing 100 percent PVA fibers, 100 percent rayon fibers, and blends
of PVA fibers and rayon fibers in the ratio of about 1:100 to about 100:1 are considered
within the scope of the invention, and those nonwoven webs having PVA:rayon within
the ratio of about 30:70 to about 70:30 are particularly preferred in this invention,
because resulting articles exhibit good hydrophilicity and strength, and are soft
to the touch.
[0019] The fibers used to make the foregoing webs typically have linear densities ranging
from about 0.5 to about 10 denier (about 0.06 to about 11 dtex), although higher denier
fibers may also be employed. ("Denier" is a unit of linear density or fineness indicating
the weight in grams for 9000 meter length of fiber while "dtex" or "decitex" is another
unit for linear density indicating the weight in grams for a 10,000 meter length of
fiber.) Fibers having linear densities from about 0.5 to 3 denier (0.06 to about 3.33
dtex) are preferred. Fibers having a length ranging from about 0.5 to about 10 cm
may be employed as a starting material for the nonwoven web, and fiber lengths ranging
from about 2 to about 8 cm are preferred.
[0020] The nonwoven web suitable for use in the articles of the invention may be made according
to well known methods including air-laying, carding, stitch-bonding, wet laying or
melt blowing and spunbonded techniques. A preferred nonwoven web is an open, lofty,
three-dimensional air-laid nonwoven material described by Hoover, et al. in U.S. Patent
No. 2,958,593, incorporated herein by reference. An air laid web may readily be formed
on commercially available equipment such as a "Rando Webber" machine (commercially
available from Rando Machine Company, New York) or by other conventional means. (See,
for example, Turbak, A. in "Nonwovens: An Advanced Tutorial", Tappi Press, Atlanta,
Georgia, 1989).
[0021] A major portion of the fibers of the substrate are bonded together with a binder
formed by curing the binder precursor. Curing refers to crosslinking reactions in
the binder precursor that result in an insoluble binder. Binders suitable in the practice
of the present invention comprise a crosslinked PVA and a hydrophobic polymer derived
from a hydrophobic latex emulsion. This hydrophobic polymer may also be crosslinked.
Preferably, the polymer derived from a hydrophobic latex emulsion is chemically bonded
(e.g., by crosslinking) to the PVA in the cured binder. Preferably the binder precursor
is comprised of a mixture of dissolved PVA, crosslinking agent, and hydrophobic latex
emulsion.
[0022] The PVA polymer may be derived from partially or completely hydrolyzed homopolymers
and copolymers of vinyl acetate. PVA polymers having varying degrees of hydrolysis,
molecular weights, and comonomers are known and are commercially available, for example,
from E.I. DuPont de Nemours Co., Inc. (Wilmington, DE) under the tradename "Elvanol",
from Air Products and Chemicals, Inc. (Allentown, PA) under the tradename "Airvol",
from Kuraray Chemical KK (Tokyo, Japan) as K, C, HL, and HL series under the trade
designations "KL-118, KL-318, KL-506, KM-118, C-118, C-506, C-318, HL-12E, HL-1203,
HL-75, HL-1108, R-1130, R-2105 and R-2130" functional polymer. All of these commercial
compositions are suitable for use in formulating the binder precusor.
[0023] A preferred PVA is a partially or completely hydrolyzed homopolymer or copolymer
derived from the copolymerization of first and second monomers. The first monomer
may be selected from the group consisting of monomers within the general formula (I)
![](https://data.epo.org/publication-server/image?imagePath=2002/44/DOC/EPNWB1/EP97935260NWB1/imgb0001)
wherein X is Si(OR
4OR
5OR
6); and
the second monomer is selected from the group comprising monomers within the general
formula (II)
![](https://data.epo.org/publication-server/image?imagePath=2002/44/DOC/EPNWB1/EP97935260NWB1/imgb0002)
wherein Y is O(CO)R
7; and R
1, R
2, R
3, R
4, R
5, R
6 and R
7 are independently selected from the group consisting of hydrogen and organic radicals
having from 1 to about 10 carbon atoms.
[0024] Silanol modified PVA is particularly preferred in the binder of the invention. Suitable
silanol modified PVA may be made by the copolymerization of any one of a number of
ethylenically unsaturated monomers having hydrolyzable groups with an alkoxysilane-substituted
ethylenically unsaturated monomer. Non-limiting examples of ethylenically unsaturated
monomers having hydrolyzable groups are vinyl acetate, acetoxyethyl acrylate, acetoxyethyl
methacrylate, and various propyl acrylate and methacrylate esters. Examples of alkoxysilane-substituted
ethylenically unsaturated monomers include vinyl trialkoxysilanes such as vinyl trimethoxysilane,
vinyl triethoxysilane, vinyl tripropoxysilane, vinyl tributoxysilane and the like.
Vinyl trimethoxysilane is preferred.
[0025] One particularly preferred silanol-modified PVA may be produced from the copolymerization
of vinyl acetate and vinyl trimethoxysilane, followed by the direct hydrolysis of
the copolymer in alkaline solution (see below). A suitable commercially available
silanol-modified PVA is that known under the trade designation "R1130" (Kuraray Chemical
KK, Japan), believed to contain from about 0.5 to about 1.0 mole percent of the silyl
groups as vinylsilane units, exhibit a degree of polymerization of about 1700, and
the degree of hydrolysis of the vinyl acetate units being about 99 percent or higher.
[0026] In the binder precursor, the PVA is mixed with a suitable crosslinking agent compatible
with the PVA. Suitable crosslinking agents include any of a variety of known crosslinking
agents including, for example, aldehydes, diisocyanates, polyacrylic acid, and various
metal complexes such as chelates of aluminum, titanium, silicon, zirconium and the
like. A variety of PVA crosslinkers are described, for example, in
Polyvinyl Alcohol - Developments, C.A. Finch, Ed., John Wiley and Sons, New York, 1992, pp 272-277, 282-285, incorporated
by reference herein. The selection of a suitable crosslinking agent is generally within
the skill of those practicing in the field. However, in the selection of a suitable
crosslinking for the articles of the invention, consideration should be given to the
desired end color of the article. Where vivid colors are desired, crosslinkers requiring
strongly acidic catalysts are generally not desirable. Consequently, formaldehyde
and other mono- and di-aldehydes are generally not preferred crosslinkers, especially
at a low pH.
[0027] Preferably the PVA is crosslinked via secondary hydroxyl groups on the PVA backbone
using chelating organic titanates as the crosslinking agent. The resultant binder
will theoretically further react with hydroxyl groups on the fibers when cured at
elevated temperatures. Particularly preferred are "dual" crosslinked PVA polymers
wherein an amorphous metal oxide is also used as a crosslinking agent to coordinate
with the silanol groups on the PVA backbone while the aforementioned titanates coordinate
with secondary hydroxyl groups, as mentioned. A particularly useful amorphous metal
oxide is commercially available under the trade designation "Nalco 8676" (Nalco Chemical,
Naperville, IL), an amorphous alumina sol with an average particle size less than
about 30 angstroms.
[0028] Particularly preferred PVA polymers are those utilizing the aforementioned amorphous
metal oxide and a chelating organic titanate crosslinking agent comprising either
dihydroxybis(ammonium lactato)titanium (commercially available under the trade designation
"Tyzor LA" from E. I. DuPont de Nemours & Co., Inc., Wilmington, DE) or titanium orthoesters
(commercially available under the trade designation "Tyzor 131" from E. I. DuPont
de Nemours & Co., Inc.).
[0029] The theoretical crosslink density for a suitable PVA polymer may range from 1 to
about 40 mole percent based on moles of ethylenically unsaturated monomer.
[0030] As earlier described the binder comprises a polymer derived from a latex emulsion
in the binder precursor. The inclusion of the latex emulsion in the binder precursor
has been shown to play an important role in the retention of pigment within the finished
article to avoid color bleed when the finished articles are subsequently exposed to
soapy water, for example. Surprisingly, retention of pigment within the binder is
accomplished by the use of a polymer derived from a hydrophobic latex emulsion without
sacrificing the desired absorbency of the finished article.
[0031] Without being bound by any particular theory, it is believed that color bleed may
result primarily from the loss of the smallest particles of pigment (typically less
than about 0.1 micrometer). During the manufacture of articles comprising a PVA binder,
binder precursors with low solids content (e.g., less than 15 percent in water) are
normally employed. In that binder precursor, the small pigment particles are believed
to lose their associated surfactant, causing particle agglomeration. The resulting
particle agglomerates are too large to be retained within the cured binder. As a consequence,
color bleed results when the agglomerated pigment particles are redispersed into water
when the finished article is rinsed with soap and water. Known procedures for mixing
pigment have been ineffective in reducing the color bleed phenomenon. The presence
of a self-crosslinking hydrophobic latex emulsion has been found to facilitate the
association of pigment particles with the latex emulsion. In turn, the pigment particles
are readily incorporated into the binder of the finished article, greatly reducing
color bleed. Moreover, this great reduction in color bleed is accomplished by the
use of relatively small amounts hydrophobic polymer.
[0032] The preferred hydrophobic latex emulsion is one which, when cured, provides a polymer
that is associated with the PVA and/or the fibers of the substrate in a manner that
resists removal upon exposure to moist or wet conditions, (e.g., exposure to soapy
water). Preferably, the latex emulsion is capable of being crosslinked to form a water
insoluble crosslinked polymer that is highly resistant to being washed from the finished
article. More preferably, the latex emulsion is self-crosslinking and, most preferably,
the latex emulsion is both self-crosslinking and capable of covalently bonding with
the PVA. To establish if a latex emulsion is hydrophobic, a latex emulsion is coated
onto a surface to form a film, then dried and cured. The wetting tension of a surface
is related to the hydrophobicity of a surface. This can be measured by using the surface
tension of water; or, more specifically, by measuring the angle formed by a drop of
water in contact with a surface. For purposes of this invention, a latex is considered
hydrophobic if, on a cured film of the latex emulsion, the advancing contact angle
of water is greater than about 45°.
[0033] The latex emulsion may be present in the binder precursor in amounts ranging from
about 0.05 percent up to about 20 percent by weight (based on dry solids). Concentrations
above about 20 percent by weight of the latex emulsion in the binder precursor are
thought to adversely affect the absorbency of the finished article. Concentrations
less than about 0.05 percent are not effective for retaining the pigment in the binder.
Preferably, the latex emulsion is present in the binder precursor in an amount from
about 1 percent to about 15 percent by weight (based on dry solids). More preferably,
the latex emulsion is present in an amount of about 3 percent to about 10 percent
by weight (based on dry solids). So that the hydrophobic polymer will not detract
from the softness of the finished article, especially when wet, the hydrophobic polymer
should have a glass transition temperature (T
g) of less than about 5° C, preferably less than about 0° C, and more preferably less
than about -15° C.
[0034] Examples of suitable hydrophobic latex emulsions for use in this invention include,
but are not limited to, those based on acrylates such as copolymers of butyl acrylate,
ethyl acrylate, acrylic acid, methacrylic acid, methyl methacrylate, acrylonitrile,
styrene, N-methylolacrylamide, etc.; polyurethanes; polyesters; and polyamides. Commercially
available latex emulsions useful in the invention include acrylate emulsions available
under the trade designations "Rohamere 132", "Rohamere 1878", "Rohamere 1900-D", "Rohamere
1970-D", "Rohamere 3045", "Rohamere 31-130", "Rohamere 4096D", "Rohamere 587", "Rohamere
84116", "Rohamere 8437", "Rohamere 8464", "Rohamere 8478", "Rohamere 8662" and "Rohamere
87219", all available from Rohm Tech Inc. (Maiden, MA). A variety of acrylic latex
emulsions having suitable physical characteristics for the practice of this invention
are commercially available under the trade designation "Rhoplex" from Rohm and Haas
Co. of Philadelphia, PA. Vinyl acetate/ethylene latex emulsions having suitable physical
characteristics are available under the trade designation "Airflex" and polyvinyl
acetate homopolymers are available under the trade designation "Vinac", both from
Air Products and Chemicals, Inc. of Allentown, PA. Preferred hydrophobic latices include
styrene -butyl acrylate available under the trade designation "Hycar T-278" from B.F.
Goodrich Co. of Akron, OH, and acrylic latices available under the trade designations
"Rhoplex E-2744" and "Rhoplex NW-1845" from Rohm and Haas Co. It will be appreciated
that other suitable hydrophobic latex emulsions can be used in the preparation of
the binder precursor.
[0035] The binder precursor comprises a solution, preferably aqueous, of dissolved PVA,
crosslinking agent and hydrophobic latex emulsion. The binder precursor may be from
about 1 percent to about 60 percent solids by weight, preferably from about 2 percent
to about 20 percent solids by weight. The binder precursor is typically prepared by
first dissolving the PVA in water, adding crosslinking agents and then adding a hydrophobic
latex with stirring.
[0036] Crosslinking of the PVA as well as of the latex emulsion should be avoided until
curing conditions (i.e., high temperatures) are present. When titanate crosslinking
agents are utilized, organic acids such as citric acid may be added to the binder
precursor to help stabilize the titanates (e.g., dihydroxybis(ammonium lactato) titanium)
in aqueous compositions until the binder precursors are exposed to crosslinking and
curing conditions. If acid activated crosslinking agents are employed (for example,
aldehydes, or aminoplast resins), then it may be desirable to incorporate a latent
acid such as diammonium phosphate into the binder precursor.
[0037] Pigments are mixed with the binder precursor. Pigments that are useful in the present
invention include inorganic and organic pigments. Inorganic pigment generally refers
to a finely divided metallic oxides or sulfides. Inorganic pigments are not soluble.
They may be highly colored for use as coloring agents or, for example, white, for
use as an opacifying agent. Organic pigment generally refers to highly colored materials
which are carbon-based, rather than metal-based. For the purposes of this invention,
an organic compound is a pigment when it imparts a desired color to the article and
is not soluble in the solvents used while making or using the articles of this invention.
[0038] Preferably, pigments are added to the binder precursor as aqueous dispersions of
finely divided particles. The particles typically range in size from sub-micrometer
to about 10 micrometers. The dispersions facilitate distribution of pigment within
the binder. Suitable aqueous dispersions of organic pigments are available from commercial
sources. These include textile and graphic arts pigment grades from companies including
Sun Chemical Co. (Fort Lee, NJ), Heucotech Ltd. (Fairless Hills, PA), Catawba Char-Lab
(Charlotte, NC), Organic Dyestuffs Co. (Charlotte, NC), Penn Color ( Doylestown, PA),
and BASF Corp. (Wyandotte, MI). Pigments also may be prepared according to methods
well known in the art.
[0039] Suitable pigments include, but are not limited to, organic pigments, for example,
azo pigments such as soluble or insoluble azo pigments or condensed azo pigments,
phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, perylene-perynone
pigments, dioxazine pigments, vat dye pigments and basic dye pigments, and inorganic
pigments such as carbon black, titanium oxide, chrome yellow, cadmium yellow, cadmium
red, red iron oxide, iron black, zinc flower, Prussian blue and ultramarine. In general,
organic pigments are preferred, because they do not contain heavy metals, such as
chromium, lead, tin and/or barium.
[0040] In addition to the above-mentioned components, it may also be desirable to add optional
ingredients to the binder precursor. Such optional ingredients include softeners (such
as ethers and alcohols), fragrances, fillers (such as for example silica, alumina,
and titanium dioxide particles), and bactericidal agents (e.g., quaternary ammonium
salts). The inclusion of these ingredients and their relative proportions within the
binder precursor will vary depending on the chemical identity of the ingredient and
its intended function as will be readily appreciated by those practicing in the field.
[0041] In the method of this invention, a substrate having the desired thickness and weight
per unit area is provided. At least a portion of the substrate is coated with a mixture
of binder precursor and pigment, dried, and heated to cure the binder precursor to
form binder and pigment on at least a portion of the substrate.
[0042] Turning now to Figure 3, a method of producing a preferred substrate, a nonwoven
web, (as illustrated in Figures 1 and 2) is shown schematically. In the preparation
of a nonwoven web, staple fibers are fed via hopper 20 (or other means) into carding
station 22. A moving conveyer transports carded web 26 from carding station 22, typically
to a crosslapper, not shown, to form a layered web having fibers oriented at various
angles relative to the machine direction of carded web 26. Carded web 26 then passes
through needle tacking station 28 to entangle the fibers, thus strengthening and consolidating
the web, and resulting in needle tacked web 30. Entanglement of the web may alternatively
be achieved by means other than needle tacking, such as by hydroentanglement.
[0043] Needle tacked web 30 may optionally pass through calender station 32 to achieve a
desired thickness, providing calendered web 34 that preferably is not more than about
1.52 mm (60 mils) thick. Calendered web 34 then passes through an immersion bath 36
where a mixture of pigment and binder precursor 37 is applied. Web 34 passes under
rollers 38 and emerges as coated web 40. Coating of the web with binder precursor
may be accomplished by immersion coating methods as well as by other coating methods
known in the art including roll coating, spray coating, gravure coating, transfer
coating and the like. During coating, at least a portion of the fibers are coated,
and preferably the web is coated on at least one of its first and second major surfaces
with a mixture of pigment and binder precursor. In the preparation of articles to
be used as hand wiping articles or the like, the web is typically coated on both of
its major surfaces. The coating weight (i.e., dry binder add-on weight) is reported
as a percentage of the weight of the finished wiping article. The coating weight ranges
from about 1 percent to about 95 percent, preferably from about 10 percent to about
60 percent, more preferably 20 percent to 40 percent.
[0044] Coated web 40 passes through drying station 42 to form dried web 44. While resident
in drying station 42, the web is typically and preferably exposed to an elevated temperature
to remove water from the binder precursor and form dried web 44. Drying may be accomplished
using heated rollers (i.e., "hot can"), a forced air oven, a radiant panel or other
known means. Preferably, drying is uniform throughout the thickness of the web. Depending
on the composition of the binder precursor, the type of crosslinking agent used, the
amount of water present and the like, web 44 may be suitable for use without further
curing.
[0045] Typically and preferably, it is desirable to first dry and then cure the binder precursor.
This two stage process is.accomplished by first drying the web as discussed above.
Dried web 44 is then passed through final curing station 46, which is maintained at
a temperature higher than the temperature of drying station 42. In the curing station,
exposure to the elevated temperature cures the binder to form dried and cured web
48. Drying and curing of the binder precursor may be accomplished by exposing dried
web 44 to more than two different temperatures by, for example, performing the drying
and the curing steps in an oven having more than two heating zones. Additionally,
in drying and curing the binder precursor, both major surfaces of the uncured web
preferably are simultaneously exposed to a heat source. Alternatively, although less
preferred, the first and second major surfaces of the coated web may be exposed in
sequence to the heat source.
[0046] Web 48 may then be passed through another set of calender rollers 50, which may used
to emboss a pattern and fuse the surfaces of the article. Web 52 generally has a thickness
of no more than 1.52 mm (60 mils), and a weight ranging from about 50 g/m
2 to about 250 g/m
2. Calendering of the binder coated web at temperatures from about 5 to about 40°C
below the melting point of the fiber may reduce the likelihood of lint attaching to
the surface of the articles and will generally provide a smooth surface. Embossing
of a textured pattern onto the wiping article may be performed simultaneously with
calendering, or in a subsequent step.
[0047] Web 52 may then pass through an optional second needling station 54 to perforate
the web for decorative or other purposes, after which the web is slit and wound onto
take-up roll 56.
[0048] Alternatively, web 52 may pass through a hot water (i.e., from about 60 to about
80°C) bath (not shown), and calendared and dried by means of heated rollers as described
above, to produced a soft "hand" or feel before being slit and wound up onto take-up
roll 56. Another way to achieve a soft feel in final packaged form and to aid in processing
is to apply a small amount of water or fungicide solution to the article immediately
prior to packaging. The cured article may be laminated or otherwise affixed to another
substrate, if desired, such as a sponge, a urethane foam backing or the like. It may
be desirable in the applications to use cured articles having a binder on only one
of the major surfaces, thus providing an untreated major surface (i.e., a surface
free of cured binder) for the application of adhesives or the like.
[0049] The articles of this invention are particularly useful as "synthetic chamois" due
to their absorbency and durability. These synthetic wiping articles are useful for
cleaning various surfaces. The presence of pigment in the article produces an aesthetically
pleasing and functional absorbent wiping article for consumer use. Preferably, the
articles are highly colored, producing readily recognizable colored articles which
are used for cleaning certain areas (e.g., green for use in kitchens). The articles
prepared according to this invention exhibit minimal color bleed due to pigment being
lost from the article during use.
[0050] The examples illustrate the preparation of webs coated with a binder and a pigment
suitable for use as absorbent articles.
MATERIALS DESCRIPTION
[0051] In the Examples, certain materials were used which are identified according to the
following abbreviations and trade designations.
PREPARATIVE PROCEDURES
[0052] The following preparative procedures were used in the preparation of the articles
identified in the Examples.
PROCEDURE A (SUBSTRATE PREPARATION)
[0053] The nonwoven web was prepared from 50 percent rayon fibers (3.0 d x 6.3 cm, T2222,
Courtaulds Fibers Inc. (Axis, AL) and 50 percent polyvinyl alcohol fibers (1.7 d x
5.3 cm, VPB174, Kuraray Co. KK (Tokyo, Japan)). The nonwoven web was prepared by carding
and crosslapping and was needlepunched to provide a web with a basis wt. of 162.9
g/m
2 (4.8 oz / yd
2) and a thickness of 1.45 mm (57 mils). For the following examples the web was coated
as pieces of dimension 30.5 cm x 38.1 cm (12 inches by 15 inches). In the production
of a nonwoven web, there is orientation of the fibers depending upon how it is produced;
thus reference is made to the "machine", or down web, direction, in contrast to the
"cross web" direction, which is orthogonal to the machine direction.
PROCEDURE B (PVA SOLUTION)
[0054] A coating solution was made by heating 9.3 parts polyvinyl alcohol ("R1130" from
Kuraray Co. KK) to boiling in 90.7 parts deionized water to dissolve the PVA. Amorphous
alumina sol (0.44 parts, "Nalco 8676" from Nalco Chemical Co.) was added to the PVA
solution followed by the addition of 4.4 parts titanate ("Tyzor 131, commercially
available from E.I. DuPont de Nemours, Co., Inc., of Wilmington, DE). The resultant
solution was cooled and then diluted with deionized water to achieve a solids content
of 3.6 weight percent when dried at 121°C (250°F).
PROCEDURE C (BINDER PRECURSOR AND WIPING ARTICLES)
[0055] Latex emulsion and pigment were added to the PVA solution in proportions described
in the examples, along with additional deionized water as indicated in the examples.
The PVA solution and the latex emulsion form the binder precursor. The mixture of
pigment and binder precursor was poured onto the substrate and evenly distributed
by hand to make a coated substrate. Then the coated substrate was air dried at 65.6
°C (150° F) until dry and heat cured at 149 °C (300° F) for 10 minutes. The amount
of the dried and cured polymer (i.e., binder) on the substrate was about 18 weight
percent.
TEST METHODS
[0056] The following Test Methods were employed in evaluating the wiping articles of the
Examples.
COLOR BLEED
[0057] Color bleed was determined by first taking a sample of material to be evaluated and
placing it in 2 liters of water and allowed to soak for 60 seconds. The sample was
then wrung out by hand and the rinse water was collected in a dishpan. The soak and
wringing steps were repeated twenty times for each material sample tested. Thereafter,
the color hue and intensity of the rinse solution and the dishpan surface were observed
and recorded, and the visible absorption spectrum of the rinse water was measured
and recorded using a 10 cm path length cell on a UV-visible spectrophotometer.
[0058] The rinse solution was then discarded from the dishpan and replaced with 2 liters
of fresh water. The sample was wrung out completely and 2 g of detergent (available
under the trade designation "Liquinox" from Alconox, Inc. of New York, New York) was
placed on the sample and rubbed in lightly over the majority of sample surface. The
thus treated sample was placed in the fresh water. The sample was then wrung out by
hand with the detergent/water mixture returned to the dishpan. The sample was again
soaked and wrung out a second time and the visible absorption spectrum of the rinse
water was measured using a 10 cm path length cell, as previously described.
TENSILE STRENGTH
[0059] Samples were prepared for testing by wetting them in water and wringing them out
once with a mechanical wringer. Samples were die cut to 2.54 x 15.24 cm (1 x 6 inch).
[0060] Tensile strength measurements were made using a tensile tester (Instron Model "TM",
obtained from Instron Corp. of Canton, MA), using a procedure modified from that of
the test method described in ASTM D 5035-95, "Standard Test Method for Breaking Force
and Elongation of Textile Fabrics (Strip Method)". The sample thickness also was recorded.
A constant rate of extension was employed, and jaws were clamp-type. Rate of jaw separation
was 25.4 cm/min (10 inches/min). The sample was placed into the jaws, set at a 2.5
cm (1 inch) gap, and the cycle was started. The tensile strength (i.e., load) and
the elongation at break were measured. The tensile strength is an indication of the
stiffness of the sample. Elongation at break is a measure of a load which is applied
and increased until the sample breaks. Measurements were done on the samples in machine
direction and the cross web direction, as mechanical properties may vary depending
upon the direction of orientation.
BLEACH STABILITY
[0061] Wiping articles were immersed for 8 hours in a mixture of 286 g of 5.25 weight percent
chlorine bleach (household strength chlorine bleach, commercially available under
the trade designation "Clorox" from The Clorox Co. of Oakland, CA) in 14 liters of
tap water. When the samples were removed from the bleach solution, they were visually
evaluated for color fading.
ELMENDORF TEAR TEST
[0062] Samples were prepared for tear testing by soaking them for 5 minutes in tepid water
and then mechanically wringing them.
[0063] Elmendorf tear tests were conducted on 6.35 x 27.94 cm (2.5 x 11 inch) die-cut, notched
(20 mm) samples, using an Elmendorf Tear Tester model number 60-32, from Thwing-Albert
Co., with a 6.4 kg pendulum. The procedure was modified from that of the test method
described in ASTM D 1424-96, "Standard Test Method for Tearing Strength of Fabrics
by Falling-Pendulum Type (Elmendorf) Apparatus". An average of four measurements is
reported. Samples were tested in both the machine direction and the transverse direction.
The tear tests are indicative of the durability of the absorbent articles of this
invention.
ABSORPTION TESTING
[0064] Water absorption was determined by first soaking a sample for 15 minutes in tepid
water in a dishpan or other container. The sample was then mechanically wrung to remove
most of the water. While still damp, 15.2 cm x 20.3 cm (6 inch x 8 inch) square portions
of the material were cut. The cut samples were again placed in a dishpan of tepid
water and allowed to soak for 15 minutes. A screen was placed under one of the cut
samples in the dishpan. After 30 seconds, the screen and the cut sample were lifted
from the dishpan, and the sample was removed from the screen with tweezers and immediately
placed onto a weighing pan with a quick smooth motion. This operation requires some
technique by the analysts and should be practiced until a reproducibility of ± 1 gram
is regularly achieved. The balance reading was recorded in grams as Total H
2O Absorbed / No Drip (A). This procedure was repeated for the remaining cut samples.
[0065] The thus-treated cut samples were soaked in a dishpan of tepid water for 5 minutes.
Thereafter, the samples were removed from the water with tweezers and then hung by
one corner using a spring clamp attached to a ring stand. After 60 seconds, each sample
was transferred onto the weighing pan with one quick smooth motion. The balance reading
in grams was recorded as Total H
2O Absorbed w/ Drip (B). This procedure was repeated for the remaining cut samples.
[0066] The cut samples were again placed in a dishpan of tepid water for 5 minutes. Thereafter,
each sample was removed from the water and passed through a mechanical wringer at
single thickness. The sample was transferred onto the weighing pan with one quick
smooth motion, and the balance reading in grams was recorded as Damp Weight (C). This
procedure was repeated for the remaining cut samples.
[0067] The cut samples were then placed into a vented forced air oven maintained at 49°C
(120°F) for at least 12 hours. Up to six samples were removed from the oven at a time
and their weight in grams was measured immediately and recorded as Dry Weight (D).
This procedure was repeated for the remaining cut samples.
[0068] The Percent Water Loss, Absorption and Effective Absorption were then calculated
according to the following formulas:
Percent Water Loss = 100 ∗ (A - B) / B;
Absorption (g water / dry weight) =(A - D) / D;
Effective Absorption (g water absorbed / m2) = 32.292 ∗ (A - C).
ABRASION TESTING
[0069] The hydrophobic latex emulsion which is present in the binder precursor dries and
cures to form a polymer which generally is expected to have poorer abrasion resistance
than that of PVA polymer alone. To illustrate the effect of added latex emulsion on
abrasion resistance, abrasion testing was performed using a Taber Abraser Model 503
equipped with H22 Calibrade wheels with 500 g weights. Samples were prepared for abrasion
testing by saturating them in tepid water and mechanically wringing the samples 4
times to remove all excess water. Destruction was recorded at the point where a visible
hole (0.3 cm (1/8 inch) diameter) in the sample appeared.
EXAMPLES
[0070] The features and advantages of the articles of the invention are further illustrated
in the following non-limiting examples.
COMPARATIVE EXAMPLE A
[0071] A red wiping article using the substrate described above in PROCEDURE A. It was coated
with 139 g of PVA solution (prepared as described in PROCEDURE B) mixed with 0.6 g
of an organic red pigment (commercially available as "Orcobrite Red BRYN 6002" from
Organic Dye Stuffs of Charlotte, NC) and 61 g deionized water. The coated sample was
dried and cured as described in PROCEDURE C.
COMPARATIVE EXAMPLE B
[0072] A blue wiping article was prepared using the substrate described above in PROCEDURE
A. It was coated with 139 g of PVA solution (prepared as described in PROCEDURE B)
mixed with 0.5 g of an organic blue pigment (commercially available as "Orcobrite
Blue 3GN 2010") and 61 g deionized water. The coated sample was dried and cured as
described in PROCEDURE C.
COMPARATIVE EXAMPLE C
[0073] A green wiping article was prepared using the substrate described above in PROCEDURE
A. It was coated with 139 g of PVA solution (prepared as described in PROCEDURE B)
mixed with 0.3 g of an organic green pigment (commercially available as "Orcobrite
Green YN 9") and 61 g deionized water. The coated sample was dried and cured as described
in PROCEDURE C.
EXAMPLE 1
[0074] This example demonstrates the preparation of a red wiping article. The sample was
prepared using the fiber web described in PROCEDURE A. It was coated with a binder
precursor mixture prepared from 132 g PVA solution (as described in PROCEDURE B),
0.45 g of a latex emulsion ("Hycar T-278"), 0.6 g of an organic red pigment ("Orcobrite
Red BRYN 6002") and 67 g deionized water. The coated sample was dried and cured as
described in PROCEDURE C. The resultant wiping article contained 5 percent of the
polymer derived from the latex emulsion ("Hycar T-278") in the binder based on dry
solids.
EXAMPLE 2
[0075] This example demonstrates the preparation of a red wiping article. The sample was
prepared using the fiber web described in PROCEDURE A. It was coated with a binder
precursor mixture prepared from 125 g PVA solution (as described in PROCEDURE B),
0.91 g of a latex emulsion ("Hycar T-278"), 0.6 g of an organic red pigment ("Orcobrite
Red BRYN 6002") and 74 g deionized water. The coated sample was dried and cured as
described in PROCEDURE C. The resultant wiping article contained 10 percent of a polymer
derived from the latex emulsion ("Hycar T-278") in the binder based on dry solids.
EXAMPLE 3
[0076] This example demonstrates the preparation of a red wiping article. The sample was
prepared using the fiber web described in PROCEDURE A. It was coated with a binder
precursor mixture prepared from 118 g PVA solution (as described in PROCEDURE B),
1.36 g of latex emulsion ("Hycar T-278"), 0.6 g of an organic red pigment ("Orcobrite
Red BRYN 6002") and 80 g deionized water. The coated sample was dried and cured as
described in PROCEDURE C. The resultant wipe contained 15 percent of polymer derived
from the latex emulsion ("Hycar T-278") in the binder based on dry solids.
EXAMPLE 4
[0077] This example demonstrates the preparation of a blue wiping article. The sample was
prepared using the fiber web described in PROCEDURE A. . It was coated with a binder
precursor mixture prepared from 125 g PVA solution (as described in PROCEDURE B),
0.91 g of latex emulsion ("Hycar T-278"), 0.5 g of an organic blue pigment ("Orcobrite
Blue 3GN 2010") and 74 g deionized water. The coated sample was dried and cured as
described in PROCEDURE C. The resultant wipe contained 10 percent of polymer derived
from the latex emulsion ("Hycar T-278") in the binder based on dry solids.
EXAMPLE 5
[0078] This example demonstrates the preparation of a green wiping article. The sample was
prepared using the fiber web described in PROCEDURE A. It was coated with a binder
precursor mixture prepared from 125 g PVA solution (as described in PROCEDURE B),
0.91 g of latex emulsion ("Hycar T-278"), 0.3 g of an organic green pigment ("Orcobrite
Green YN 9") and 74 g deionized water. The coated sample was dried and cured as described
in PROCEDURE C. The resultant wipe contained 10 percent of polymer derived from the
latex emulsion ("Hycar T-278") in the binder based on dry solids.
[0079] The detailed results of analytical testing of performance changes are given below
in Table 1.
COMPARATIVE EXAMPLES A-C AND EXAMPLES 1-5
Tensile Test Results:
[0080] Tensile strength measurements were made as described in the test method for TENSILE
STRENGTH, above. The. tensile strength and elongation at break were measured in the
machine (Direction 1) and cross web (Direction 2) direction of the sample. No significant
deterioration of tensile properties was observed, indicating that there was little
detrimental effect caused by the incorporation of a hydrophobic latex emulsion ("Hycar
T-278").
Table 1
Tensile Testing |
Example |
Orientat ion |
Load at Peak Maximum (lb/in) |
Standard Deviation |
% Elongation at Peak Maximum |
Standard Deviation |
C. Ex. A |
Direction 1 |
29.8 |
1.9 |
60 |
2 |
" |
Direction 2 |
38.1 |
2.5 |
75 |
3 |
1 |
Direction 1 |
35.5 |
0.7 |
68 |
4 |
" |
Direction 2 |
38.4 |
1.2 |
76 |
3 |
2 |
Direction 1 |
30.6 |
1.4 |
70 |
4 |
" |
Direction 2 |
37.3 |
1.8 |
75 |
3 |
3 |
Direction 1 |
32.9 |
1.2 |
63 |
8 |
" |
Direction 2 |
41.2 |
2.5 |
78 |
4 |
Bleach Stability:
[0081] Wiping articles made according to Comparative Example A and Example 2 were tested
for bleach stability according to the above Bleach Stability Test Method. When the
samples were removed from the bleach solution, the immersed sample from Comparative
Example A had faded in color level compared to non-immersed wiping articles from Comparative
Example A, while the immersed sample from Example 2 remained vividly red, with less
apparent color fading. No negative effects were observed on bleach stability using
the latex additive.
[0082] Tensile Testing was conducted on these samples, both before and after exposure to
the bleach solution. The data are reported in Table 2.
Table 2
Tensile Test
(Bleached Samples) |
Sample |
Orientation |
Load at Peak Maximum (lb/in) |
Standard Deviation |
% Tensile Load Loss |
Before bleach |
|
|
|
|
Comparative
Example A |
Direction 1 |
29.8 |
1.9 |
|
|
Direction 2 |
38.1 |
2.5 |
|
2 |
Direction 1 |
30.6 |
1.4 |
|
|
Direction 2 |
37.3 |
1.8 |
|
8 hrs in 2% bleach |
|
|
|
|
Comparative
Example A |
Direction 1 |
13.1 |
1.0 |
56 |
|
Direction 2 |
15.2 |
1.0 |
61 |
2 |
Direction 1 |
17.3 |
0.9 |
43 |
|
Direction 2 |
21.4 |
2.3 |
43 |
Tear Test Results:
[0083] Tear tests were conducted for the articles of Comparative Example A and Examples
1-3 as described in the ELMENDORF TEAR TEST, above. The data are set forth in Table
3. The data indicate that there is no deleterious effect on the tear resistance of
the samples due to the presence of a polymer derived from a hydrophobic latex emulsion.
Table 3
Tear Test |
Example |
Orientation |
Average |
Standard Deviation |
Comparative Example A |
Direction 1 |
68 |
15 |
|
Direction 2 |
89 |
7 |
Comparative Example A |
Direction 1 |
76 |
15 |
|
Direction 2 |
80 |
11 |
1 |
Direction 1 |
76 |
11 |
|
Direction 2 |
73 |
14 |
2 |
Direction 1 |
69 |
10 |
|
Direction 2 |
67 |
11 |
2 |
Direction 1 |
74 |
18 |
|
Direction 2 |
76 |
16 |
3 |
Direction 1 |
74 |
14 |
|
Direction 2 |
88 |
8 |
Absorption Testing:
[0084] Absorption testing according to the above ABSORPTION TESTING Method indicated no
significant effect on absorption due to the presence of a polymer derived from a hydrophobic
latex emulsion. The data are reported in Table 4.
Table 4
Water Absorption |
Example |
% Water Loss |
Absorption (g water / g dry sample) |
Effective Absorption (g water absorbed / ft2) |
Comparative Example A |
16.54 |
6.42 |
90.57 |
Comparative Example A |
16.16 |
5.79 |
84.00 |
Example 1 |
14.34 |
6.23 |
90.90 |
Example 2 |
17.42 |
6.39 |
97.95 |
Example 2 |
14.57 |
6.14 |
87.69 |
Example 3 |
17.60 |
6.41 |
87.96 |
Abrasion Testing
[0085] Samples were abraded according to the Abrasion Testing Method with destruction of
the sample recorded at the point where a visible hole (0.32 cm (1/8 inch) diameter)
appeared. The data are set forth in Table 5. The data indicate that there is no deleterious
effect on the abrasion resistance of the samples due to the presence of a polymer
derived from a hydrophobic latex emulsion.
Table 5
Abrasion Test |
Example |
Cycles to Destruction |
Comparative Example A |
1228 |
1 |
1126 |
2 |
1419 |
2 |
1677 |
3 |
1668 |
Color Bleed
[0086] Wiping articles were subjected to the color bleed test as follows. In the case of
red, blue, and green wiping articles of the Comparative Examples A, B and C, heavy
color bleed was observed with wringing in water, and severe color bleed was observed
on wringing with detergent. In contrast, at most a faint color could be detected after
wringing with detergent in the case of the wiping articles with 10 percent or more
added latex. The results with 5 percent addition of the "Hycar T-278" latex were intermediate
to the 0 and 10 percent levels.
[0087] The data are set forth in Table 6 at the wavelength of maximum color absorption for
each sample.
Table 6
Color Bleed |
Example |
Wavelength (nm) |
Absorption After Water Rinse |
Absorption After Soap Rinse |
percent Reduction In Color Bleed |
Comparative Example A |
525 |
0.4062 |
1.0285 |
NA |
1 |
525 |
0.0377 |
0.1759 |
91 |
2 |
525 |
0.0149 |
0.0875 |
83 |
3 |
525 |
0.0093 |
0.1008 |
90 |
Comparative Example B |
625 |
0.5034 |
0.8764 |
NA |
4 |
625 |
0.0110 |
0.0374 |
96 |
Comparative Example C |
650 |
0.2986 |
1.0900 |
NA |
5 |
650 |
0.0318 |
0.0932 |
91 |
COMPARATIVE EXAMPLE D
[0088] A red wiping article was prepared using the substrate described above in PROCEDURE
A. It was coated with 152 g of PVA solution prepared as described in PROCEDURE B mixed
with 0.3 g of an organic red pigment (commercially available as "Orcobrite Red BRYN
6002") and 61 g deionized water. The coated sample was dried and cured as described
in PROCEDURE C. The binder content of the resultant cured wiping article was 14 percent
(based on dry solids).
EXAMPLE 6
[0089] A red wiping article was prepared using the fiber web as described in PROCEDURE A.
It was coated with a binder precursor mixture prepared from 137 g PVA solution (as
described in PROCEDURE B), 1.2 g of latex emulsion ("Rhoplex NW-1845", a non-crosslinking
latex), 0.63 g of an organic red pigment ("Orcobrite Red BRYN 6002") and 61 g deionized
water. The coated sample was dried and cured as described in PROCEDURE C. The binder
content of the resultant cured wipe was 15 percent.
EXAMPLE 7
[0090] A red wiping article was prepared using the fiber web described in PROCEDURE A. It
was coated with a binder precursor mixture prepared from 137 g PVA solution (as described
in PROCEDURE B), 1.2 g of latex emulsion ("Rhoplex ST-954", an acrylic self-crosslinking
emulsion), 0.63 g of an organic red pigment ("Orcobrite Red BRYN 6002") and 61 g deionized
water. The coated sample was dried and cured as described in PROCEDURE C. The binder
content of the resultant cured wipe was 15 percent.
EXAMPLE 8
[0091] A red wiping article was prepared using the fiber web described in PROCEDURE A. It
was coated with a binder precursor mixture prepared from 137 g PVA solution (as described
in PROCEDURE B), 1.2 g of a styrene-butadiene self-crosslinking latex emulsion ("Unocal
4170"), 0.64 g of an organic red pigment ("Orcobrite Red BRYN 6002") and 61 g deionized
water. The coated sample was dried and cured as described in PROCEDURE C. The binder
content of the resultant cured wipe was 15 percent.
COMPARATIVE EXAMPLE D and EXAMPLES 6-8
[0092] The articles of Examples 6, 7, 8 and Comparative Example D were evaluated for color
bleed according to the above Color Bleed Test Method. The observed color bleed of
Examples 6, 7 and 8 was significantly less than that for Comparative Example D.
1. An absorbent article comprising:
(a) a substrate comprised of organic fibers having a plurality of pendant hydroxyl
groups;
(b) a binder coated on at least a portion of the fibers, the binder comprising a crosslinked
polyvinyl alcohol and a hydrophobic polymer derived from a hydrophobic latex emulsion;
and
(c ) pigment distributed within the binder.
2. The absorbent article of Claim 1, wherein the substrate comprises a nonwoven web.
3. The absorbent article of Claim 2, wherein the nonwoven web has a weight per unit area
ranging from about 50 g/m2 to about 250 g/m2.
4. The absorbent article of Claim 1, wherein the organic fibers comprise materials selected
from the group of polyvinyl alcohol and rayon.
5. The absorbent article of Claim 4, wherein the ratio of polyvinyl alcohol fibers to
rayon fibers ranges from 30:70 to 70:30.
6. The absorbent article of Claim 1, wherein the polyvinyl alcohol is a silanol-modified
polyvinyl alcohol.
7. The absorbent article of Claim 6, wherein the silanol-modified polyvinyl alcohol is
crosslinked with a metal complex selected from the group of aluminum, titanium, silicon,
and zirconium chelates and combinations of the foregoing.
8. The absorbent article of Claim 1, wherein the hydrophobic polymer is derived from
a self-crosslinking latex emulsion.
9. The absorbent article of Claim 1, wherein the hydrophobic polymer is derived from
a hydrophobic latex emulsion based on materials selected from the group of acrylate,
acrylic acid, methacrylic acid, acrylonitrile, styrene, N-methylolacrylamide, polyurethane,
polyester, and polyamide.
10. The absorbent article of Claim 9, wherein the acrylate is selected from the group
of butyl acrylate, ethyl acrylate, and methyl methacrylate.
11. The absorbent article of Claim 1, wherein the hydrophobic polymer has a glass transition
temperature of less than 0°C.
12. The absorbent article of Claim 1 wherein the hydrophobic polymer has a glass transition
temperature of less than -15°C.
13. The absorbent article of Claim 1 wherein the hydrophobic polymer is present in the
range of 1 to 15 weight percent of the binder.
14. The absorbent article of Claim 1, wherein the pigment is an organic pigment.
15. The absorbent article of Claim 1, wherein the polyvinyl alcohol is a hydrolyzed, crosslinked
homopolymer or copolymer derived from the copolymerization of first and second monomers,
the first monomer consisting of monomers within the general formula (I)
![](https://data.epo.org/publication-server/image?imagePath=2002/44/DOC/EPNWB1/EP97935260NWB1/imgb0003)
wherein X is Si(OR
4OR
5OR
6); and
the second monomer consisting of monomers within the general formula (II)
![](https://data.epo.org/publication-server/image?imagePath=2002/44/DOC/EPNWB1/EP97935260NWB1/imgb0004)
wherein Y is O(CO)R
7; and R
1, R
2, R
3, R
4, R
5, R
6 and R
7 are independently selected from the group consisting of hydrogen and organic radicals
having from 1 to about 10 carbon atoms.
16. The absorbent article of Claim 15, wherein the polyvinyl alcohol is crosslinked with
a crosslinking agent selected from the group of aldehydes, diisocyanates, polyacrylic
acid, metal complexes, and combinations of the foregoing.
17. The absorbent article of Claim 16, wherein the metal complexes are selected from the
group of aluminum, titanium, silicon, and zironium chelates and combinations of the
foregoing.
18. The absorbent article of Claim 15, wherein the polyvinyl alcohol is crosslinked via
secondary hydroxyl groups on the polymer backbone using organic titanates as the crosslinking
agent, and silanol groups on the polymer backbone are crosslinked using metal oxides
as another crosslinking agent.
19. A method of making an absorbent article, the method comprising:
(a) providing a substrate comprising organic fibers having a plurality of pendant
hydroxyl groups;
(b) coating at least a portion of the fibers with a mixture of a pigment and a binder
precursor, the binder precursor comprising polyvinyl alcohol and a hydrophobic latex
emulsion; and
(c) curing the binder precursor to provide an absorbent article.
20. The method of claim 19 wherein the providing step (a) further comprises providing
the substrate in the form of a carded and crosslapped nonwoven web.
21. The method of claim 19 wherein the providing step (a) further comprises providing
the substrate in the form of a nonwoven web having first and second major surfaces,
and entangling the organic fibers within the nonwoven web by needletacking.
22. The method of claim 21, wherein the nonwoven web has a weight per unit area ranging
from about 50 g/m2 to about 250 g/m2.
23. The method of claim 19 wherein the coating step (b) comprises coating at least one
of the first and second major surfaces of the nonwoven web with the binder precursor.
24. The method of claim 19, wherein the organic fibers comprise materials selected from
the group of polyvinyl alcohol and rayon.
25. The method of claim 24, wherein the ratio of polyvinyl alcohol fibers to rayon fibers
ranges from 30:70 to 70:30.
26. The method of claim 19, wherein the hydrophobic latex emulsion comprises a self-crosslinking
polymer.
27. The method of claim 19, wherein the hydrophobic latex emulsion is based on materials
selected from the group of acrylate, acrylic acid, methacrylic acid, acrylonitrile,
styrene, N-methylolacrylamide, polyurethane, polyester, and polyamide.
28. The method of claim 27 wherein the acrylate is selected from the group of butyl acrylate,
ethyl acrylate, and methyl methacrylate.
29. The method of claim 19, wherein the hydrophobic latex emulsion is present in the range
of 1 to 15 weight percent of the binder.
30. The method of claim 19, wherein the pigment is an organic pigment.
31. The method of claim 19, wherein the polyvinyl alcohol in the binder precursor is a
homopolymer or copolymer derived from the copolymerization of first and second monomers,
the first monomer consisting of monomers within the general formula (I)
![](https://data.epo.org/publication-server/image?imagePath=2002/44/DOC/EPNWB1/EP97935260NWB1/imgb0005)
wherein X is Si(OR
4OR
5OR
6); and
the second monomer consisting of monomers within the general formula (II)
![](https://data.epo.org/publication-server/image?imagePath=2002/44/DOC/EPNWB1/EP97935260NWB1/imgb0006)
wherein Y is O(CO)R
7; and R
1, R
2, R
3, R
4, R
5, R
6 and R
7 are independently selected from the group consisting of hydrogen and organic radicals
having from 1 to about 10 carbon atoms.
32. The method of claim 31, wherein the binder precursor further comprises a crossllinking
agent compatible with the polyvinyl alcohol, the crosslinking agent selected from
the group of aldehydes, diisocyanates, polyacrylic acid, metal complexes, and combinations
of the foregoing.
33. The method of claim 32, wherein the metal complexes are selected from the group of
aluminum, titanium, silicon, and zirconium chelates and combinations of the foregoing.
34. The method of claim 31, wherein curing step (c ) comprises a crosslinking reaction
wherein the polyvinyl alcohol is crosslinked via secondary hydroxyl groups on the
polymer backbone using organic titanates as the crosslinking agent, and silanol groups
on the polymer backbone are crosslinked using metal oxides as another crosslinking
agent.
35. The absorbent article of claim 1 comprising a substrate having first and second major
surfaces, the substrate comprising organic fibers having a plurality of pendant hydroxyl
groups, wherein at least one of the first and second major surfaces is coated with
a mixture comprising
the binder and
pigment distributed within the binder.
36. The absorbent article of Claim 35, wherein the substrate comprises a nonwoven web.
37. The absorbent article of Claim 36, wherein the nonwoven web has a weight per unit
area ranging from about 50 g/m2 to about 250 g/m2.
38. The absorbent article of Claim 36, wherein the organic fibers comprise materials selected
from the group of polyvinyl alcohol and rayon.
39. The absorbent article of Claim 36, wherein the polyvinyl alcohol is a silanol-modified
polyvinyl alcohol.
40. The absorbent article of Claim 39, wherein the silanol-modified polyvinyl alcohol
is crosslinked with a metal complex selected from the group of aluminum, titanium,
silicon, and zirconium chelates and combinations of the foregoing.
41. The absorbent article of Claim 36, wherein the hydrophobic polymer is derived from
a hydrophobic latex emulsion based on materials selected from the group of acrylate,
acrylic acid, methacrylic acid, acrylonitrile, styrene, N-methylolacrylamide, polyurethane,
polyester, and polyamide.
42. The absorbent article of Claim 36, wherein the hydrophobic polymer is present in the
range of 1 to 15 weight percent of the binder.
43. The absorbent article of Claim 36, wherein the pigment is an organic pigment.
1. Absorbierender Gegenstand, umfassend:
(a) ein Substrat, bestehend aus organischen Fasern mit einer Vielzahl anhängender
Hydroxylgruppen;
(b) ein Bindemittel, das auf mindestens einen Teil der Fasern beschichtet ist, wobei
das Bindemittel einen vernetzten Polyvinylalkohol und ein hydrophobes Polymer umfasst,
das aus einer hydrophoben Latexemulsion stammt; und
(c) im Bindemittel verteiltes Pigment.
2. Absorbierender Gegenstand nach Anspruch 1, wobei das Substrat ein Faservliesgewebe
umfasst.
3. Absorbierender Gegenstand nach Anspruch 2, wobei das Faservliesgewebe ein Gewicht
pro Einheitsfläche von etwa 50 g/m2 bis etwa 250 g/m2 hat.
4. Absorbierender Gegenstand nach Anspruch 1, wobei die organischen Fasern Materialien
umfassen, die aus Polyvinylalkohol und Reyon ausgewählt sind.
5. Absorbierender Gegenstand nach Anspruch 4, wobei das Verhältnis von Polyvinylalkohol-Fasern
zu Reyon-Fasern im Bereich von 30:70 bis 70:30 liegt.
6. Absorbierender Gegenstand nach Anspruch 1, wobei der Polyvinylalkohol ein silanolmodifizierter
Polyvinylalkohol ist.
7. Absorbierender Gegenstand nach Anspruch 6, wobei der silanolmodifizierte Polyvinylalkohol
mit einem Metallkomplex vernetzt ist, der aus Aluminium-, Titan-, Silicium- und Zirkonchelaten
und Kombinationen der Vorstehenden ausgewählt ist.
8. Absorbierender Gegenstand nach Anspruch 1, wobei das hydrophobe Polymer aus einer
selbstvernetzenden Latexemulsion stammt.
9. Absorbierender Gegenstand nach Anspruch 1, wobei das hydrophobe Polymer aus einer
hydrophoben Latexemulsion stammt, die auf Materialien basiert, ausgewählt aus Acrylat,
Acrylsäure, Methacrylsäure, Acrylnitril, Styrol, N-Methylolacrylamid, Polyurethan,
Polyester und Polyamid.
10. Absorbierender Gegenstand nach Anspruch 9, wobei das Acrylat aus Butylacrylat, Ethylacrylat
und Methylmethacrylat ausgewählt ist.
11. Absorbierender Gegenstand nach Anspruch 1, wobei das hydrophobe Polymer eine Glasübergangstemperatur
von weniger als 0°C hat.
12. Absorbierender Gegenstand nach Anspruch 1, wobei das hydrophobe Polymer eine Glasübergangstemperatur
von weniger als -15°C hat.
13. Absorbierender Gegenstand nach Anspruch 1, wobei das hydrophobe Polymer im Bereich
von 1 bis 15 Gew% des Bindemittels vorliegt.
14. Absorbierender Gegenstand nach Anspruch 1, wobei das Pigment ein organisches Pigment
ist.
15. Absorbierender Gegenstand nach Anspruch 1, wobei der Polyvinylalkohol ein hydrolysiertes,
vernetztes Homopolymer oder Copolymer ist, das aus der Copolymerisation von ersten
und zweiten Monomeren stammt, wobei das erste Monomer aus Monomeren der allgemeinen
Formel (I) besteht
![](https://data.epo.org/publication-server/image?imagePath=2002/44/DOC/EPNWB1/EP97935260NWB1/imgb0007)
wobei X die Bedeutung Si(OR
4OR
5OR
6) hat; und
das zweite Monomer aus Monomeren der allgemeinen Formel (II) besteht
![](https://data.epo.org/publication-server/image?imagePath=2002/44/DOC/EPNWB1/EP97935260NWB1/imgb0008)
wobei Y die Bedeutung O(CO)R
7 hat und R
1, R
2, R
3, R
4, R
5, R
6 und R
7 unabhängig aus einem Wasserstoffatom und organischen Resten mit 1 bis etwa 10 Kohlenstoffatomen
ausgewählt sind.
16. Absorbierender Gegenstand nach Anspruch 15, wobei der Polyvinylalkohol mit einem Vernetzungsmittel
vernetzt wird, das aus Aldehyden, Diisocyanaten, Polyacrylsäure, Metallkomplexen und
Kombinationen der Vorstehenden ausgewählt ist.
17. Absorbierender Gegenstand nach Anspruch 16, wobei die Metallkomplexe aus Aluminium-,
Titan-, Silicium- und Zirkonchelaten und Kombinationen der Vorstehenden ausgewählt
sind.
18. Absorbierender Gegenstand nach Anspruch 15, wobei der Polyvinylalkohol über sekundäre
Hydroxylgruppen am Polymergrundgerüst unter Verwendung von organischen Titanaten als
Vernetzungsmittel vernetzt ist und Silanolgruppen am Polymergrundgerüst unter Verwendung
von Metalloxiden als weiterem Vernetzungsmittel vernetzt sind.
19. Verfahren zur Herstellung eines absorbierenden Gegenstandes, wobei das Verfahren umfasst:
(a) Bereitstellen eines Substrates, das organische Fasern mit einer Vielzahl von anhängenden
Hydroxylgruppen umfasst;
(b) Beschichten mindestens eines Teils der Fasern mit einem Gemisch aus einem Pigment
und einer Bindemittel-Vorstufe, wobei die Bindemittel-Vorstufe Polyvinylalkohol und
eine hydrophobe Latexemulsion umfasst; und
(c) Härten der Bindemittel-Vorstufe um einen absorbierenden Gegenstand bereitzustellen.
20. Verfahren nach Anspruch 19, wobei der Bereitstellungsschritt (a) ferner die Bereitstellung
des Substrats in Form eines kardierten und kreuzgelegten Faservliesgewebes umfasst.
21. Verfahren nach Anspruch 19, wobei der Bereitstellungsschritt (a) ferner die Bereitstellung
des Substrats in Form eines Faservliesgewebes mit ersten und zweiten Hauptoberflächen
sowie das Verstricken der organischen Fasern mit dem Faservliesgewebe mittels Nadelheften
umfasst.
22. Verfahren nach Anspruch 21, wobei das Faservliesgewebe ein Gewicht pro Einheitsfläche
von etwa 50 g/m2 bis etwa 250 g/m2 hat.
23. Verfahren nach Anspruch 19, wobei der Beschichtungsschritt (b) das Beschichten von
mindestens einer der ersten und zweiten Hauptoberflächen des Faservliesgewebes mit
der Bindemittel-Vorstufe umfasst.
24. Verfahren nach Anspruch 19, wobei die organischen Fasern Materialien umfassen, die
aus Polyvinylalkohol und Reyon ausgewählt sind.
25. Verfahren nach Anspruch 24, wobei das Verhältnis von Polyvinylalkohol-Fasern zu Reyon-Fasern
im Bereich von 30:70 bis 70:30 liegt.
26. Verfahren nach Anspruch 19, wobei die hydrophobe Latexemulsion ein selbstvernetzendes
Polymer umfasst.
27. Verfahren nach Anspruch 19, wobei die hydrophobe Latexemulsion auf Materialien basiert,
die aus Acrylat, Acrylsäure, Methacrylsäure, Acrylnitril, Styrol, N-Methylolacrylamid,
Polyurethan, Polyester und Polyamid ausgewählt sind.
28. Verfahren nach Anspruch 27, wobei das Acrylat aus Butylacrylat, Ethylacrylat und Methylmethacrylat
ausgewählt ist.
29. Verfahren nach Anspruch 19, wobei die hydrophobe Latexemulsion im Bereich von 1 bis
15 Gew% des Bindemittels vorliegt.
30. Verfahren nach Anspruch 19, wobei das Pigment ein organisches Pigment ist.
31. Verfahren nach Anspruch 19, wobei der Polyvinylalkohol in der Bindemittel-Vorstufe
ein Homopolymer oder Copolymer ist, das aus der Copolymerisation von ersten und zweiten
Monomeren stammt, wobei das erste Monomer aus Monomeren der allgemeinen Formel (I)
besteht
![](https://data.epo.org/publication-server/image?imagePath=2002/44/DOC/EPNWB1/EP97935260NWB1/imgb0009)
wobei X die Bedeutung Si(OR
4OR
5OR
6) hat; und
das zweite Monomer aus Monomeren der allgemeinen Formel (II) besteht
![](https://data.epo.org/publication-server/image?imagePath=2002/44/DOC/EPNWB1/EP97935260NWB1/imgb0010)
wobei Y die Bedeutung O(CO)R
7 hat und R
1, R
2, R
3, R
4, R
5, R
6 und R
7 unabhängig einem Wasserstoffatom und organischen Resten mit 1 bis etwa 10 Kohlenstoffatomen
ausgewählt sind.
32. Verfahren nach Anspruch 31, wobei die Bindemittel-Vorstufe ferner ein Vernetzungsmittel
umfasst, das mit dem Polyvinylalkohol verträglich ist, und das Vernetzungsmittel aus
Aldehyden, Diisocyanaten, Polyacrylsäure, Metallkomplexen und Kombinationen der Vorstehenden
ausgewählt ist.
33. Verfahren nach Anspruch 32, wobei die Metallkomplexe aus Aluminium-, Titan-, Silicium-
und Zirkonchelaten und Kombinationen der Vorstehenden ausgewählt sind.
34. Verfahren nach Anspruch 31, wobei der Härtungsschritt (c) eine Vernetzungsreaktion
umfasst, wobei der Polyvinylalkohol über sekundäre Hydroxylgruppen am Polymergrundgerüst
unter Verwendung von organischen Titanaten als Vernetzungsmittel vernetzt wird und
Silanolgruppen am Polymergrundgerüst unter Verwendung von Metalloxiden als weiterem
Vernetzungsmittel vernetzt werden.
35. Absorbierender Gegenstand nach Anspruch 1, umfassend ein Substrat mit ersten und zweiten
Hauptoberflächen, wobei das Substrat organische Fasern mit einer Vielzahl anhängender
Hydroxylgruppen umfasst, wobei mindestens eine der ersten und zweiten Hauptoberflächen
mit einem Gemisch beschichtet ist, umfassend das Bindemittel und
im Bindemittel verteiltes Pigment.
36. Absorbierender Gegenstand nach Anspruch 35, wobei das Substrat ein Faservliesgewebe
umfasst.
37. Absorbierender Gegenstand nach Anspruch 36, wobei das Faservliesgewebe ein Gewicht
pro Einheitsfläche von etwa 50 g/m2 bis etwa 250 g/m2 hat.
38. Absorbierender Gegenstand nach Anspruch 36, wobei die organischen Fasern Materialien
umfassen, die aus Polyvinylalkohol und Reyon ausgewählt sind.
39. Absorbierender Gegenstand nach Anspruch 36, wobei der Polyvinylalkohol ein silanolmodifizierter
Polyvinylalkohol ist.
40. Absorbierender Gegenstand nach Anspruch 39, wobei der silanolmodifizierte Polyvinylalkohol
mit einem Metallkomplex vernetzt ist, der aus Aluminium-, Titan-, Silicium- und Zirkonchelaten
und Kombinationen der Vorstehenden ausgewählt sind.
41. Absorbierender Gegenstand nach Anspruch 36, wobei das hydrophobe Polymer aus einer
hydrophoben Latexemulsion stammt, die auf Materialien basiert, ausgewählt aus der
Gruppe mit Acrylat, Acrylsäure, Methacrylsäure, Acrylnitril, Styrol, N-Methylolacrylamid,
Polyurethan, Polyester und Polyamid.
42. Absorbierender Gegenstand nach Anspruch 36, wobei das hydrophobe Polymer im Bereich
von 1 bis 15 Gew% des Bindemittels vorliegt.
43. Absorbierender Gegenstand nach Anspruch 36, wobei das Pigment ein organisches Pigment
ist.
1. Article absorbant comprenant :
(a) un substrat composé de fibres organiques ayant une pluralité de groupes hydroxyles
pendants ;
(b) un liant déposé sur au moins une partie des fibres, le liant comprenant un poly(alcool
de vinyle) réticulé et un polymère hydrophobe dérivé d'une émulsion de latex hydrophobe
; et
(c) un pigment réparti à l'intérieur du liant.
2. Article absorbant selon la revendication 1, dans lequel le substrat comprend une toile
non tissée.
3. Article absorbant selon la revendication 2, dans lequel la toile non tissée possède
un grammage compris entre environ 50 g/m2 et environ 250 g/m2.
4. Article absorbant selon la revendication 1, dans lequel les fibres organiques comprennent
des matières choisies dans le groupe formé par le poly(alcool de vinyle) et la rayonne.
5. Article absorbant selon la revendication 4, dans lequel le rapport des fibres de poly(alcool
de vinyle) aux fibres de rayonne est compris entre 30:70 et 70:30.
6. Article absorbant selon la revendication 1, dans lequel le poly(alcool de vinyle)
est un poly(alcool de vinyle) modifié par un silanol.
7. Article absorbant selon la revendication 6, dans lequel le poly(alcool de vinyle)
modifié par un silanol est réticulé avec un complexe métallique choisi dans le groupe
formé par les chélates d'aluminium, de titane, de silicium et de zirconium et les
combinaisons des précédents.
8. Article absorbant selon la revendication 1, dans lequel le polymère hydrophobe est
dérivé d'une émulsion de latex auto-réticulante.
9. Article absorbant selon la revendication 1, dans lequel le polymère hydrophobe est
dérivé d'une émulsion de latex hydrophobe basée sur des matières choisies dans le
groupe formé par l'acrylate, l'acide acrylique, l'acide méthacrylique, l'acrylonitrile,
le styrène, le N-méthylolacrylamide, le polyuréthanne, le polyester et le polyamide.
10. Article absorbant selon la revendication 9, dans lequel l'acrylate est choisi dans
le groupe formé par l'acrylate de butyle, l'acrylate d'éthyle et le méthacrylate de
méthyle.
11. Article absorbant selon la revendication 1, dans lequel le polymère hydrophobe possède
une température de transition vitreuse inférieure à 0°C.
12. Article absorbant selon la revendication 1, dans lequel le polymère hydrophobe possède
une température de transition vitreuse inférieure à -15°C.
13. Article absorbant selon la revendication 1, dans lequel le polymère hydrophobe est
présent dans la gamme de 1 à 15 pour cent en poids du liant.
14. Article absorbant selon la revendication 1, dans lequel le pigment est un pigment
organique.
15. Article absorbant selon la revendication 1, dans lequel le poly(alcool de vinyle)
est un homopolymère ou copolymère réticulé hydrolysé dérivé de la copolymérisation
des premier et deuxième monomères, le premier monomère étant composé de monomères
inclus dans la formule générale (I)
![](https://data.epo.org/publication-server/image?imagePath=2002/44/DOC/EPNWB1/EP97935260NWB1/imgb0011)
dans laquelle X est Si(OR
4OR
5OR
6) ; et
le deuxième monomère étant composé de monomères inclus dans la formule générale (II)
![](https://data.epo.org/publication-server/image?imagePath=2002/44/DOC/EPNWB1/EP97935260NWB1/imgb0012)
dans laquelle Y est O(CO)R
7 ; et R
1, R
2, R
3, R
4, R
5, R
6 et R
7 sont, indépendamment les uns des autres, choisis dans le groupe formé par l'hydrogène
et les radicaux organiques ayant de 1 à environ 10 atomes de carbone.
16. Article absorbant selon la revendication 15, dans lequel le poly(alcool de vinyle)
est réticulé avec un agent de réticulation choisi dans le groupe formé par les aldéhydes,
les diisocyanates, le poly(acide acrylique), les complexes métalliques et les combinaisons
des précédents.
17. Article absorbant selon la revendication 16, dans lequel les complexes métalliques
sont choisis dans le groupe formé par les chélates d'aluminium, de titane, de silicium
et de zirconium et les combinaison des précédents.
18. Article absorbant selon la revendication 15, dans lequel le poly(alcool de vinyle)
est réticulé par l'intermédiaire de groupes hydroxyle secondaires sur le squelette
polymère en utilisant les titanates organiques en tant qu'agent de réticulation, et
les groupes silanol sur le squelette polymère sont réticulés en utilisant des oxydes
métalliques en tant qu'autre agent de réticulation.
19. Procédé pour fabriquer un article absorbant, le procédé consistant à :
(a) fournir un substrat composé de fibres organiques ayant une pluralité de groupes
hydroxyles pendants ;
(b) revêtir au moins une partie des fibres d'un mélange de pigment et de précurseur
liant, le précurseur liant comprenant un poly(alcool de vinyle) et une émulsion de
latex hydrophobe ; et
(c) durcir le précurseur liant pour obtenir un article absorbant.
20. Procédé selon la revendication 19, dans lequel l'étape de fourniture (a) consiste
de plus à fournir le substrat sous forme d'une toile non tissée cardée et chevauchée.
21. Procédé selon la revendication 19, dans lequel l'étape de fourniture (a) consiste
de plus à fournir le substrat sous forme d'une toile non tissée ayant des première
et deuxième surfaces principales et enserrant les fibres organiques à l'intérieur
de la toile non tissée par faufilure à l'aiguille.
22. Procédé selon la revendication 21, dans lequel la toile non tissée possède un grammage
compris entre environ 50 g/m2 et environ 250 g/m2.
23. Procédé selon la revendication 19, dans lequel l'étape de revêtement (b) consiste
à revêtir au moins une des première et deuxième surfaces principales de la toile non
tissée avec le précurseur liant.
24. Procédé selon la revendication 19, dans lequel les fibres organiques comprennent des
matières choisies dans le groupe formé par le poly(alcool de vinyle) et la rayonne.
25. Procédé selon la revendication 24, dans lequel le rapport des fibres de poly(alcool
de vinyle) aux fibres de rayonne est compris entre 30:70 et 70:30.
26. Procédé selon la revendication 19, dans lequel l'émulsion de latex hydrophobe comprend
un polymère auto-réticulant.
27. Procédé selon la revendication 19, dans lequel l'émulsion de latex hydrophobe est
basée sur des matières choisies dans le groupe formé par l'acrylate, l'acide acrylique,
l'acide méthacrylique, l'acrylonitrile, le styrène, le N-méthylolacrylamide, le polyuréthanne,
le polyester et le polyamide.
28. Procédé selon la revendication 27, dans lequel l'acrylate est choisi dans le groupe
formé par l'acrylate de butyle, l'acrylate d'éthyle et le méthacrylate de méthyle.
29. Procédé selon la revendication 19, dans lequel l'émulsion de latex hydrophobe est
présente dans la gamme de 1 à 15 pour cent en poids du liant.
30. Procédé selon la revendication 19, dans lequel le pigment est un pigment organique.
31. Procédé selon la revendication 19, dans lequel le poly(alcool de vinyle) dans le précurseur
liant est un homopolymère ou copolymère dérivé de la copolymérisation des premier
et deuxième monomères, le premier monomère étant composé de monomères inclus dans
la formule générale (I)
![](https://data.epo.org/publication-server/image?imagePath=2002/44/DOC/EPNWB1/EP97935260NWB1/imgb0013)
dans laquelle X est Si(OR
4OR
5OR
6) ; et
le deuxième monomère étant composé de monomères inclus dans la formule générale (II)
![](https://data.epo.org/publication-server/image?imagePath=2002/44/DOC/EPNWB1/EP97935260NWB1/imgb0014)
dans laquelle Y est O(CO)R
7; et R
1, R
2, R
3, R
4, R
5, R
6 et R
7 sont, indépendamment les uns des autres, choisis dans le groupe formé par l'hydrogène
et les radicaux organiques ayant de 1 à environ 10 atomes de carbone.
32. Procédé selon la revendication 31, dans lequel le précurseur liant comprend de plus
un agent de réticulation compatible avec le poly(alcool de vinyle), l'agent de réticulation
choisi dans le groupe formé par les aldéhydes, les diisocyanates, le poly(acide acrylique),
les complexes métalliques et les combinaison des précédents.
33. Procédé selon la revendication 32, dans lequel les complexes métalliques sont choisis
dans le groupe formé par les chélates d'aluminium, de titane, de silicium et de zirconium
et les combinaison des précédents.
34. Procédé selon la revendication 31, dans lequel l'étape de durcissement (C) comprend
une réaction de réticulation dans laquelle le poly(alcool de vinyle) est réticulé
par l'intermédiaire de groupes hydroxyle secondaires sur le squelette polymère en
utilisant les titanates organiques en tant qu'agent de réticulation, et les groupes
silanol sur le squelette polymère sont réticulés en utilisant des oxydes métalliques
en tant qu'autre agent de réticulation.
35. Article absorbant selon la revendication 1, comprenant un substrat ayant des première
et deuxième surfaces principales, le substrat comprenant des fibres organiques ayant
une pluralité de groupes hydroxyles pendants, dans lesquels au moins une des première
et deuxième surfaces principales est revêtue d'un mélange comprenant le liant et le
pigment réparti à l'intérieur du liant.
36. Article absorbant selon la revendication 35, dans lequel le substrat comprend une
toile non tissée.
37. Article absorbant selon la revendication 36, dans lequel la toile non tissée possède
un grammage compris entre environ 50 g/m2 et environ 250 g/m2.
38. Article absorbant selon la revendication 36, dans lequel les fibres organiques comprennent
des matières choisies dans le groupe formé par le poly(alcool de vinyle) et la rayonne.
39. Article absorbant selon la revendication 36, dans lequel le poly(alcool de vinyle)
est un poly(alcool de vinyle) modifié par un silanol.
40. Article absorbant selon la revendication 39, dans lequel le poly(alcool de vinyle)
modifié par un silanol est réticulé avec un complexe métallique choisi dans le groupe
formé par les chélates d'aluminium, de titane, de silicium et de zirconium et les
combinaisons des précédents.
41. Article absorbant selon la revendication 36, dans lequel le polymère hydrophobe est
dérivé d'une émulsion de latex hydrophobe basée sur des matières choisies dans le
groupe formé par l'acrylate, l'acide acrylique, l'acide méthacrylique, l'acrylonitrile,
le styrène, le N-méthylolacrylamide, le polyuréthanne, le polyester et le polyamide.
42. Article absorbant selon la revendication 36, dans lequel le polymère hydrophobe est
présent dans la gamme de 1 à 15 pour cent en poids du liant.
43. Article absorbant selon la revendication 36, dans lequel le pigment est un pigment
organique.