U.S. patent application number 10/835883 was filed with the patent office on 2005-11-03 for surface treated paper product.
This patent application is currently assigned to Kimberly-Clark Worldwide, Inc.. Invention is credited to Reddy, Kiran Kumar Karrem.
Application Number | 20050241789 10/835883 |
Document ID | / |
Family ID | 35185893 |
Filed Date | 2005-11-03 |
United States Patent
Application |
20050241789 |
Kind Code |
A1 |
Reddy, Kiran Kumar Karrem |
November 3, 2005 |
Surface treated paper product
Abstract
A soft tissue product includes a surface treatment composition
disposed on a treated portion that extends to the edges of the
product, but which leaves the corners of the product untreated. The
shape of the treated portion effectively ensures consumer benefit
while reducing the total amount of additive composition on the
product by placing the treatment composition in the portion of the
product that is most likely to come into contact with the skin of a
user.
Inventors: |
Reddy, Kiran Kumar Karrem;
(Roswell, GA) |
Correspondence
Address: |
KIMBERLY-CLARK WORLDWIDE, INC.
401 NORTH LAKE STREET
NEENAH
WI
54956
|
Assignee: |
Kimberly-Clark Worldwide,
Inc.
|
Family ID: |
35185893 |
Appl. No.: |
10/835883 |
Filed: |
April 30, 2004 |
Current U.S.
Class: |
162/134 ;
162/158; 162/172; 162/179 |
Current CPC
Class: |
D21H 27/02 20130101;
A47K 10/16 20130101; D21H 27/008 20130101 |
Class at
Publication: |
162/134 ;
162/158; 162/179; 162/172 |
International
Class: |
D21H 027/00; D21H
023/22; D21H 017/13; D21H 017/14; D21H 017/60 |
Claims
1. A tissue product comprising a substrate defining a major surface
having a rectangular planar surface area defining first and third
opposed edges, second and fourth opposed edges, and first, second,
third, and fourth corner portions, the tissue product further
comprising a treated portion comprising an additive composition
disposed on the major surface, wherein the treated portion
intersects the first, second, third, and fourth edges of the major
surface, and even further wherein the corner portions of the major
surface are untreated.
2. The tissue product of claim 1, wherein the treated portion has a
substantially parallelogram shape, the treated portion being
positioned on the major surface wherein the corners of the
parallelogram-shaped treated portion substantially bisect the edges
of the major surface.
3. The tissue product of claim 1, wherein the treated portion has a
substantially elliptical shape, the circumference of the
elliptical-shaped treated portion substantially bisecting the edges
of the major surface.
4. The tissue product of claim 1, wherein the additive composition
is applied at an add-on level of from about 0.01 to about 20
percent of the basis weight of the substrate.
5. The tissue product of claim 1, wherein the treated portion
comprises from about 100 to about 1,000,000 individual deposits of
treatment composition per square inch of the planar surface
area.
6. The tissue product of claim 1, wherein the treated portion
covers from about 50 to about 80 percent of the planar surface
area.
7. The tissue product of claim 1, wherein the treated portion is
divided into two parts separated by an intervening untreated
portion.
8. The tissue product of claim 7, wherein the intervening untreated
portion extends from the first edge of the major surface to the
third edge.
9. The tissue product of claim 8, wherein the two parts of the
treated portion each extends from the first edge of the major
surface to the third edge.
10. The tissue product of claim 8, wherein the tissue product is
folded along the intervening untreated portion.
11. The tissue product of claim 1, wherein the additive composition
comprises from about 30 to about 90 weight percent oil and from
about 10 to about 40 weight percent wax, said composition having a
melting point of from about 30.degree. C. to about 70.degree.
C.
12. The tissue product of claim 11, wherein the add-on level of the
additive composition is from about 3 to about 15 weight percent of
the basis weight of the substrate.
13. The tissue product of claim 11, wherein the additive
composition further comprises from about 5 to about 40 weight
percent fatty alcohol.
14. The tissue product of claim 11, wherein the amount of oil in
the composition is from about 40 to about 70 weight percent.
15. The tissue product of claim 11, wherein the amount of wax in
the composition is from about 10 to about 30 weight percent.
16. The tissue product of claim 1, wherein the additive composition
comprises a silicone compound.
17. The tissue product of claim 16, wherein the add-on level is
from about 0.5 to about 3 weight percent of the basis weight of the
substrate.
18. A hand towel comprising the tissue product of claim 1.
19. A facial tissue comprising the tissue product of claim 1.
20. A multi-ply tissue product comprising first and second outer
plies and an inner ply, wherein the outer plies comprise the tissue
product of claim 1.
21. A method of making a tissue product comprising the steps of:
providing a tissue web and an additive composition; applying the
additive composition to the tissue web; and recovering the tissue
product of claim 1.
22. A tissue product comprising a substrate defining a major
surface having a rectangular planar surface area defining first and
third opposed edges, second and fourth opposed edges, and first,
second, third, and fourth corner portions, the tissue product
further comprising a treated portion comprising an additive
composition disposed on the major surface, wherein the treated
portion extends from the first edge of the major surface to the
third edge, further wherein the treated portion extends from the
second edge of the major surface to the fourth edge, and even
further wherein the corner portions of the major surface are
untreated.
23. A tissue product comprising a substrate defining a major
surface having a rectangular planar surface area, the tissue
product further comprising a treated portion comprising an additive
composition disposed on the major surface, the treated portion
having a substantially parallelogram shape, the treated portion
being positioned on the major surface wherein the corners of the
parallelogram-shaped treated portion substantially bisect the sides
of the major surface.
Description
BACKGROUND OF THE INVENTION
[0001] Absorbent tissue products such as facial tissue, bath
tissue, hand towels, and so forth have been used to absorb fluids
on the skin and leave the skin dry. Frequent use of these products
may, however, tend to irritate or abrade the skin. In particular,
during frequent hand-drying, the skin can become so irritated as to
appear red and be sore to the touch. To reduce skin irritation,
tissue products have included additives applied to the tissue
surfaces to reduce or eliminate irritated skin during heavy use
periods. The additives can enhance sheet softness perceptions by
reducing the stiffness of the sheet, making it more drapeable, or
by providing lubricity, helping the sheet glide across the surface
of the skin. The additives may also be deposited on the skin.
[0002] The general approach in the industry has been that the
greater the quantity of additive on the tissue, the greater the
benefit. Contributing to this approach is the fact that particular
additives may be absorbed into the tissue, leaving less additive on
the surface to provide the intended benefit. One major drawback to
the "more is better" philosophy is cost. Additives to address skin
irritation can represent a significant portion of the cost of a
tissue sheet. Additionally, application of the additives to the
entire surface of a tissue sheet can result in waste when the user
does not utilize the entire sheet.
[0003] Thus, there is a need for an additive-treated tissue product
adapted to maximize the effectiveness and efficiency of the
additive and to enhance sheet softness and/or reduce skin
irritation and redness.
SUMMARY OF THE INVENTION
[0004] In one aspect of the invention, a tissue product includes a
substrate defining a major surface having a rectangular planar
surface area defining first and third opposed edges, second and
fourth opposed edges, and first, second, third, and fourth corner
portions. The tissue product further includes a treated portion
including an additive composition disposed on the major surface
wherein the treated portion intersects the first, second, third,
and fourth edges of the major surface, and even further wherein the
corner portions of the major surface are untreated. In one
embodiment, the treated portion has a substantially parallelogram
shape and is positioned on the major surface wherein the corners of
the parallelogram-shaped treated portion substantially bisect the
edges of the major surface. In another embodiment, the treated
portion has a substantially elliptical shape and the circumference
of the elliptical-shaped treated portion substantially bisects the
edges of the major surface.
[0005] In one embodiment, the treated portion may be divided into
more than one part, for example, two, three, or four parts, with
the parts being separated by one or more intervening untreated
portions. When the tissue product includes two treated parts on one
surface, the intervening untreated portion desirably extends from
one edge of the major surface to the opposed or opposite edge.
Additionally, when the tissue product includes two treated parts on
one surface, the two parts of the treated portion desirably each
extend from one edge of the major surface to the opposed or
opposite edge. The tissue product may be folded, and when the
tissue product includes two treated parts on one surface the tissue
product is, when folded, desirably folded along the intervening
untreated portion.
[0006] The additive composition desirably may be applied at an
add-on level of from about 0.01 to about 20 percent of the basis
weight of the substrate. Desirably, the treated portion covers from
about 50 to about 80 percent of the planar surface area of the
tissue product. In one embodiment, the treated portion includes
from about 100 to about 1,000,000 individual deposits of treatment
composition per square inch of the planar surface area.
[0007] In one embodiment, the additive composition includes from
about 30 to about 90 weight percent oil and from about 10 to about
40 weight percent wax, said composition having a melting point of
from about 30.degree. C. to about 70.degree. C. Desirably, the
amount of oil in the composition is from about 40 to about 70
weight percent and the amount of wax in the composition is from
about 10 to about 30 weight percent. The add-on level of this
additive composition is desirably from about 3 to about 15 weight
percent of the basis weight of the substrate. The additive
composition may further include from about 5 to about 40 weight
percent fatty alcohol.
[0008] In another embodiment, the additive composition includes a
silicone compound. The add-on level is desirably from about 0.5 to
about 3 weight percent of the basis weight of the substrate.
[0009] The tissue product of the invention may be suitable for use,
for example, as facial tissue, bath tissue, hand towels, napkins,
multi-ply tissue products, and so forth.
[0010] In one aspect of the invention, a method of making a tissue
product includes the steps of: providing a tissue web and an
additive composition; applying the additive composition to the
tissue web; and recovering the tissue product of claim 1. In one
embodiment, the additive composition is applied to the tissue web
using a rotogravure process.
[0011] In another aspect of the invention, a tissue product
includes a substrate defining a major surface having a rectangular
planar surface area defining first and third opposed edges, second
and fourth opposed edges, and first, second, third, and fourth
corner portions. The tissue product further includes a treated
portion that includes an additive composition disposed on the major
surface, wherein the treated portion extends from the first edge of
the major surface to the third edge, and further wherein the
treated portion extends from the second edge of the major surface
to the fourth edge, and even further wherein the corner portions of
the major surface are untreated.
[0012] In a further aspect of the invention, a tissue product
includes a substrate defining a major surface having a rectangular
planar surface area. The tissue product further includes a treated
portion that includes an additive composition disposed on the major
surface. The treated portion has a substantially parallelogram
shape and is positioned on the major surface wherein the corners of
the parallelogram-shaped treated portion substantially bisect the
sides of the major surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] A full and enabling disclosure of this invention, including
the best mode shown to one of ordinary skill in the art, is set
forth in this specification.
[0014] FIG. 1 representatively shows a tissue product according to
the present invention.
[0015] FIG. 2 representatively shows an alternate embodiment of a
tissue product according to the present invention.
[0016] FIG. 3 is a schematic process flow diagram for a method of
making a tissue base sheet in which an additive composition is
applied to a creped tissue sheet during manufacture using a heated
rotogravure printer.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Reference now will be made to the embodiments of the
invention, one or more examples of which are set forth below. Each
embodiment is provided by way of explanation of the invention, not
as a limitation of the invention. In fact, it will be apparent to
those skilled in the art that various modifications and variations
can be made in this invention without departing from the scope or
spirit of the invention. For example, features illustrated or
described as part of one embodiment can be used on another
embodiment to yield a still further embodiment. Thus, it is
intended that the present invention cover such modifications and
variations as come within the scope of the appended claims and
their equivalents. Other objects, features and aspects of the
present invention are disclosed in or are obvious from the
following detailed description
[0018] It has now been discovered that, surprisingly, tissue
products containing an additive adapted to reduce skin irritation
and redness can be manufactured with substantially lower total
add-on amounts while maintaining the overall effectiveness of the
additive. Applicants have discovered that application of additive
to the surface of a tissue product to form a treated portion that
receives more contact with the skin of a user during the use of the
tissue product can be used effectively to provide consumer benefit
while minimizing the total amount of additive on the tissue. It is
theorized that consumers do not use the entire surface area of
tissue products. For example, in studies conducted on hand drying,
it has been shown that the corners of rectangular towels are used
to a much lesser extent than the central portion of the hand
towels. Therefore, concentrating the additive in the portion of the
paper product that is more extensively utilized will maximize the
benefit to the user for a given amount of additive applied to the
tissue product. Alternatively, similar performance is achieved at a
lower cost.
[0019] FIG. 1 representatively shows a tissue product 100 that
includes a substrate 102 that defines a major surface 104.
Desirably, the major surface 104 has a substantially rectangular
planar surface area. The major surface 104 defines a plurality of
edges 106, 108, 110, 112. The first edge 106 is opposed by the
third edge 110. The second edge 108 is opposed by the fourth edge
112. The tissue product further includes a treated portion 114 that
includes an additive composition disposed on the major surface 104.
The treated portion 114 approaches and/or intersects the edges 106,
108, 110, 112. The tissue product 100 further includes corner
portions 116, 118, 120, 122 that remain untreated by the additive
composition. The additive composition is disposed on the treated
portion 114 at an add-on level that may range from about 0.01
percent to about 40 percent of the basis weight of the substrate.
The treated portion 114 may have any of a variety of contiguous
shapes. For example, the treated portion 114 may be shaped
generally as a diamond or parallelogram as depicted in FIG. 1.
Alternatively, the treated portion 114 may be shaped generally as a
circle, ellipse, oval, and so forth. In a further embodiment, the
treated portion 114 may have an irregular shape that extends to the
edges of the of the tissue product 100 and allows the corner
portions 116, 118, 120, 122 to remain untreated.
[0020] Alternate embodiments include tissue products having a
treated portion that is separated into two or more parts. FIG. 2
representatively shows a tissue product 200 that includes a
substrate 202 that defines a major surface 204. Desirably, the
major surface 204 has a substantially rectangular planar surface
area. The major surface 204 defines a plurality of edges 206, 208,
210, 212. The first edge 206 is opposed by the third edge 210. The
second edge 208 is opposed by the fourth edge 212. The tissue
product further includes a treated portion 214 that includes an
additive composition disposed on the major surface 204. The treated
portion 214 includes two sections 214A, 214B. The first section
214A approaches and/or intersects the first, second, and third
edges 206, 208, 210. The second section 214B approaches and/or
intersects the second, third, and fourth edges 208, 210, 212. The
tissue product 200 further includes corner portions 216, 218, 220,
222 that remain untreated by the additive composition. Optionally,
the tissue product 200 may further include a fold 224. Desirably,
the fold 224 is placed between the first section 214A and the
second section 214B. It is also contemplated that the tissue
product may include multiple folds, some of which may extend
through the treated portion of the tissue product, depending upon
the desired configuration or intended use.
[0021] The tissue product of this invention can be one-ply,
two-ply, three-ply or more. In all cases, the additive composition
is desirably applied to the outer surface(s) of the product. The
composition can be applied after the plies are brought together or
prior to bringing the plies together. The individual plies can be
layered or non-layered (homogeneous). In one embodiment, a
three-ply tissue product may treated wherein the outer surfaces of
the outer plies may include a treated portion as described above
that includes a first composition for which transfer of the first
composition to the skin of the user is desirable, such as, for
example, a softener, lotion, and so forth. The middle ply may be
treated with a second composition for which transfer of the second
composition may not be desirable, such as, for example, an
antiviral composition, an antibacterial composition, and so
forth.
[0022] The add-on amounts, and the number, size, shape, and
position of the treated portions, can be selected to maximize the
overall benefit provided to the consumer while minimizing the total
add-on amount. The term "add-on level" refers to the basis weight
of additive composition in the treated portion, and is typically
measured as a percentage of the substrate basis weight. The treated
portion may be present on one or both surfaces of the tissue. The
add-on level in the treated portion is desirably set as the level
of the selected additive that provides a high degree of
satisfaction on the part of the consumer. The actual basis weight
values for the selected additive may need to be determined by
comparing the consumer benefits obtained from a series of test
tissue products that differ from one another only in the additive
add-on amount, each having a uniform application of the additive
deposited on one surface or both surfaces.
[0023] The number, size, shape and position of the treated portions
on a particular tissue are selected so as to obtain the same or
substantially the same consumer benefit as would be obtainable from
a tissue having an additive applied to the entire surface. It
should be readily appreciated that a wide variety of configurations
of the shape and position of the treated portion may be possible.
The specific size of the treated portion will depend upon the
desired effect of the composition and the specific composition.
[0024] Another aspect of the invention relates to a method of
making the tissue products described above. The method comprises
the steps of: providing a tissue web and an additive composition;
applying the additive composition to the tissue web in the treated
portion at the appropriate add-on rate; and recovering from the
rotogravure process a tissue product having the additive
composition disposed in a treated portion.
[0025] One particularly beneficial method is to uniformly apply the
composition to the surface of the tissue web within each of the
zones by rotogravure printing, either direct or indirect (offset),
because it is a very exact printing process and offers maximum
control of the composition distribution and transfer rate. However,
other application methods, such as flexographic printing, spraying,
extruding, and the like can also be used. Typical of gravure
printing, the additive composition in the treated portion may
actually be present in a large number of small, spaced apart
deposits on the tissue surface. These deposits are desirably
uniformly positioned within each section of the treated portion but
only cover part of the surface in each section. When viewed by the
naked eye, the large number of small spaced-apart deposits appears
to cover the entire surface, but in fact do not. The actual surface
area coverage of the deposits can be from about 40 to about 80
percent, more specifically from about 50 to about 75 percent. For
purposes of the present invention, the surface area of the treated
portion includes the complete area circumscribed by the pattern of
deposits, and not just the actual surface area coverage of the
deposits.
[0026] Gravure printing is ideally suited to such an application by
providing, for example, from about 10 to about 1000 deposits per
lineal inch of surface, or from about 100 to about 1,000,000
deposits per square inch. Each deposit results from an individual
cell on a printing roll, so that the density of the deposits
corresponds to the density of the cells.
[0027] Gravure printing encompasses several well known engraving
techniques, such as mechanical engraving, acid-etch engraving,
electronic engraving and ceramic laser engraving. A suitable
electronic engraved example for a primary delivery zone is about
200 deposits per lineal inch of surface, or about 40,000 deposits
per square inch. By providing such a large number of small
deposits, the uniformity of the deposit distribution is very high.
Also, because of the large number of small deposits applied to the
surface of the tissue, the deposits more readily re-solidify on the
surface of the tissue where they are most effective in benefiting
the user. As a consequence, a relatively low amount of the
composition can be used to cover a large area.
[0028] The add-on rate is also determined by the volume of the
gravure roll engraving. Typically, this is expressed in terms of
the volume of the cells per square inch of engraved area. The
volume in the primary delivery regions will deliver more additive
composition than the volume in the supplementary delivery regions.
The range of liquid cell volume for a primary delivery region,
described in terms of cubic billion microns (CBM) per square inch,
is suitably from about 0.5 to about 15 CBM per square inch, more
specifically from about 1 to about 10 CBM per square inch, and
still more specifically from about 1.5 to about 8 CBM per square
inch. The range of liquid cell volume for a supplementary delivery
region is suitably from 0.1 to about 10 CBM per square inch, more
specifically from about 0.5 to about 8 CBM per square inch, and
still more specifically from about 0.75 to about 6 CBM per square
inch.
[0029] The additive composition or compositions can be applied to
one or both outer surfaces of a tissue. The additive composition
can be water-based or oil-based. Suitable water-based compositions
include, but are not limited to, emulsions and water-dispersible
compositions which can contain, for example, debonders (cationic,
anionic or nonionic surfactants), or polyhydroxy compounds such as
glycerin or propylene glycol. The basesheet could be treated with a
bi-component system comprising a debonder and a polyhydroxy
compound. Both components can be added separately or mixed together
prior to being applied to the basesheet. In particular embodiments,
the treated portions on the opposite sides of the tissue could
comprise different additive compositions.
[0030] In particular embodiments, the tissue products are made by
applying, on the surface(s) of the tissue, large numbers of
individual deposits of a melted moisturizing/protective additive
composition comprising a wax and an oil, and thereafter
re-solidifying the composition to form a distribution, of solid
deposits on the surface(s) of the tissue. Because the composition
is a solid at room temperature and rapidly solidifies after
deposition, it has less tendency to penetrate and migrate into the
sheet. Compared to tissues treated with liquid formulations, this
leaves a greater percentage of the added composition on the surface
of the tissue where it can contact and/or transfer to the user's
skin to provide a benefit. Furthermore, a lower add-on amount can
be used in the treated portion to deliver the same benefit at lower
cost because of the efficient placement of the composition
substantially at the surface of the product.
[0031] The additive composition may comprise solidified deposits of
a composition comprising from about 30 to about 90 weight percent
oil, and from about 10 to about 40 weight percent wax, desirably
also containing from about 5 to about 40 weight percent fatty
alcohol, said composition having a melting point of from about
30.degree. C. to about 70.degree. C., more specifically from about
40.degree. C. to about 60.degree. C. For purposes herein, "melting
point" is the temperature at which the majority of the melting
occurs, it being recognized that melting actually occurs over a
range of temperatures.
[0032] The amount of oil in the composition can be from about 30 to
about 90 weight percent, more specifically from about 40 to about
70 weight percent, and still more specifically from about 45 to
about 60 weight percent. Suitable oils include, but are not limited
to, the following classes of oils: petroleum or mineral oils, such
as mineral oil and petrolatum; animal oils, such as mink oil and
lanolin oil; plant oils, such as aloe extract, sunflower oil and
avocado oil; and silicone oils, such as dimethicone and alkyl
methyl silicones.
[0033] The amount of wax in the composition can be from about 10 to
about 40 weight percent, more specifically from about 10 to about
30 weight percent, and still more specifically from about 15 to
about 25 weight percent. Suitable waxes include, but are not
limited to the following classes: natural waxes, such as beeswax
and carnauba wax; petroleum waxes, such as paraffin and ceresine
wax; silicone waxes, such as alkyl methyl siloxanes; or synthetic
waxes, such as synthetic beeswax and synthetic sperm wax.
[0034] The amount of fatty alcohol in the composition, if present,
can be from about 5 to about 40 weight percent, and more
specifically from about 10 to about 30 weight percent. Suitable
fatty alcohols include alcohols having a carbon chain length of
C14-C30, including acetyl alcohol, stearyl alcohol, behenyl
alcohol, and dodecyl alcohol.
[0035] In order to better enhance the benefits to consumers,
additional ingredients can be used. The classes of ingredients and
their corresponding benefits include, without limitation, C10 or
greater fatty alcohols (lubricity, body, opacity); fatty esters
(lubricity, feel modification); vitamins (topical medicinal
benefits); dimethicone (skin protection); powders (lubricity, oil
absorption, skin protection); preservatives and antioxidants
(product integrity); ethoxylated fatty alcohols; (wettability,
process aids); fragrance (consumer appeal); lanolin derivatives
(skin moisturization), colorants, optical brighteners, sunscreens,
alpha hydroxy acids, natural herbal extracts, and the like.
[0036] The above additive composition may be applied to one or both
outer surfaces of the tissue by heating the composition to a
temperature above the melting point of the composition, for
instance a melting point of from about 30.degree. C. to about
70.degree. C., thereby causing the composition to melt. The
additive is then uniformly applied within the treated portion at
the predetermined add-on amount by uniformly applying the melted
composition to one or both surfaces of a tissue web in spaced-apart
deposits. Thereafter, the deposits of the melted composition are
re-solidified. Re-solidification of the deposits can occur almost
instantaneously, without the need for external cooling means such
as chill rolls, if the composition is heated to a temperature only
slightly above or at the melting point of the composition. However,
external cooling means such as chill rolls, either before or after
the application of the melt, can be used if desired to accelerate
re-solidification. Such instantaneous re-solidification tends to
impede penetration of the composition into the tissue and retain it
on the surface of the tissue, which is advantageous. For example,
the temperature of the melted composition can advantageously be
above the melting point about 10.degree. C. or less, more
specifically about 5.degree. C. or less, and still more
specifically about 2.degree. C. or less. As the temperature of the
melted composition approaches the melting point, the viscosity of
the melted composition generally increases, which further enhances
the tendency of the melted composition to be retained on the
surface.
[0037] Surface additive compositions of the foregoing type
comprising a wax and an oil are disclosed in International Patent
Application PCT/US96/01243 published Aug. 15, 1996 and identified
as WO 96/24722; and International Patent Application PCT/US96/01297
published Aug. 15, 1996 and identified as WO 96/24723; the
disclosures of which are incorporated herein by reference.
[0038] The total tissue add-on amount of the additive composition
can be from about 0.01 to about 40 weight percent, more
specifically from about 0.3 to about 15 weight percent, and still
more specifically from about 0.5 to about 10 weight percent, based
on the weight of the tissue. The add-on amount will depend upon the
desired effect of the composition on the product attributes and the
specific composition. Generally, though, with respect to an
additive composition of the foregoing type comprising a wax and an
oil, the add-on amount is suitably from about 1 to about 35 weight
percent, more specifically from about 3 to about 15 weight percent,
and still more specifically from about 4 to about 10 weight
percent, based on the weight of the tissue.
[0039] The additive composition may alternatively comprise a
silicone compound. Suitable silicone compounds are those silicone
compounds which provide a smooth, lubricated surface feel,
desirably without smearing glass. Desirably the silicone compounds
are present in an aqueous emulsion and/or solution for ease in
handling and processing. A wide variety of such silicone compounds
are known in the art. Specific suitable silicone compositions
include, without limitation, polydimethyl siloxanes; mixtures of
polydimethyl siloxanes and alkylene oxide-modified polydimethyl
siloxanes; organomodified polysiloxanes; mixtures of cyclic- and
non-cyclic-modified dimethyl siloxane; and the like. Number average
molecular weights are generally about 10,000 or greater. Also
suitable are aqueous mixtures of tetraethoxy silane, dimethyl
diethoxy silane, and ethylene oxide/dimethyl siloxane copolymer. A
desired composition contains about 5 weight percent tetraethoxy
silane, about 5 weight percent dimethyl diethoxy silane, and about
2 weight percent ethylene oxide/dimethyl siloxane copolymer in
water. In such silane mixtures, the ethylene oxide-dimethyl
siloxane acts as a coupling agent to bind the silicone to the
tissue sheet surface, thus retarding residue build-up on the
contact surface and thereby reducing the greasy feeling associated
with some lubricants.
[0040] Surface additive compositions of the foregoing type
comprising a silicone compound are disclosed in U.S. Pat. No.
4,950,545 issued Aug. 21, 1990 and U.S. Pat. No. 5,227,242 issued
Jul. 13, 1993, both to Walter et al.; the disclosures of which are
incorporated herein by reference.
[0041] The total amount of silicone solids in the tissue sheet can
be from about 0.1 to about 5 weight percent, based on the finished
basis weight of the tissue sheet. Desirably the amount of the
silicone compound is from about 0.5 to about 3 weight percent and
most desirably from about 0.7 to about 2 weight percent. Amounts
below 0.1 weight percent alone provide little benefit to the tissue
in terms of softness improvement. Amounts above 5 weight percent
may become economically unattractive.
[0042] The add-on amount of an additive composition comprising a
silicone compound is suitably from about 0.1 to about 5 weight
percent, more specifically from about 0.5 to about 3 weight
percent, and still more specifically from about 0.7 to about 2
weight percent, based on the weight of the tissue.
[0043] The silicone compound can be incorporated into the facial
tissue by any suitable means, including printing, spraying, dipping
and the like. The silicone compound can be incorporated into the
tissue sheet at any point in the tissue manufacturing process.
Desirably the silicone compound is printed onto a dried tissue
sheet between the base sheet manufacturing process and the final
tissue product converting process. Printing provides precise
control of the add-on amount of the silicone compound and places
the silicone compound on the surface of the tissue in the treated
portion.
[0044] For purposes herein, "tissue sheet" is a single ply sheet
suitable for facial tissue, bath tissue, towels, napkins, or the
like having a density of from about 0.04 grams per cubic centimeter
to about 0.3 grams per cubic centimeter and a basis weight of from
about 4 to about 40 pounds per 2880 square feet. Tensile strengths
in the machine direction are in the range of from about 100 to
about 5,000 grams per inch of width. Tensile strengths in the
cross-machine direction are in the range of from about 50 to about
2500 grams per inch of width. Cellulosic tissue sheets of
paper-making fibers are desirable, although synthetic fibers can be
present in significant amounts.
[0045] The tissue sheet can be made in any suitable manner. In this
regard, a variety of conventional papermaking apparatus may be used
in the application of this invention, as they are known by persons
of skill in the art. Conventional operations may be used with
respect to the stock preparation, headbox, forming fabrics, web
transfers, and through-air drying. For example, paper products
utilized in the present invention can be made utilizing adhesive
creping, wet creping, double creping, embossing, wet-pressing,
air-pressing, through- air drying, creped through-air drying,
uncreped through-air drying, as well as other steps known in the
paper art. By way of illustration, various tissue making processes
are disclosed in U.S. Pat. No. 5,607,551 issued Mar. 4, 1997 to
Farrington and U.S. Pat. No. 5,667,636 issued Sep. 16, 1997 to
Engel et al., which are incorporated herein by reference.
[0046] Referring to FIG. 3, a representative method of carrying out
this invention is shown. FIG. 3 illustrates a tissue sheet 301
approaching a Yankee dryer 302 and being dislodged from the dryer
with a creping blade 303. The dried creped tissue sheet 304 is
passed to a heated rotogravure printing station comprising a
backing roll 306 and an engraved roll 307, at which point the
melted additive composition is applied to one surface of the tissue
sheet. The treated tissue sheet is then wound into a roll 308 for
subsequent converting operations.
[0047] During the printing operation, the melted composition to be
applied to the tissue sheet is supplied by a heated supply tank 310
and pumped to a heated doctor application head 311 by a suitable
metering pump. It is desirable to maintain constant temperature in
the process. Accordingly, the melted composition may be continually
circulated between the supply tank and the application head while
maintaining an adequate amount in the reservoir. The heated doctor
applicator head supplies the melted composition to the engraved
roll 307, the surface of which contains a plurality of small cells
that form the pattern to be printed on the final tissue product. As
previously noted, the configuration and add-on rates of the cells
are selected to provide the transfer volume necessary to achieve
the desired tactile effect.
[0048] In operation the engraved roll 307 is loaded to the backing
roll 306 to force the tissue web or sheet into contact with the
engraved roll. The backing roll can be any material that meets the
process requirements such as natural rubber, synthetic rubber or
other compressible surfaces. Loading pressures can vary from
approximately 5-50 pounds per lineal inch (roll to roll
interference) to a gravure roll/backing roll gap of 0.008" (no roll
to roll contact).
[0049] In a further embodiment, the tissue sheet to be printed with
the melted composition may be supplied from a parent roll. In such
an off-line process, the printing operation is carried out
independently of the tissue sheet manufacturing process. The sheet
to be printed with the melted composition can be a single ply or it
can be multiple plies. The resulting sheet is then wound into a
roll for further converting operations. Even further, the additive
may be printed on both sides of the tissue sheet using two printing
stations in sequence. Two-sided printing is desirable when the
effect of the composition is desired on both sides and/or the
tissue sheet consists of two or more plies.
[0050] It is understood by one of ordinary skill in the art that
the present discussion is a description of exemplary embodiments
only, and is not intended as limiting the broader aspects of the
present invention, which broader aspects are embodied in the
exemplary constructions. The invention is shown by example in the
appended claims.
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