U.S. patent application number 11/726588 was filed with the patent office on 2008-09-25 for softening compositions for treating tissues which retain high rate of absorbency.
Invention is credited to Kou-Chang Liu.
Application Number | 20080230196 11/726588 |
Document ID | / |
Family ID | 39643835 |
Filed Date | 2008-09-25 |
United States Patent
Application |
20080230196 |
Kind Code |
A1 |
Liu; Kou-Chang |
September 25, 2008 |
Softening compositions for treating tissues which retain high rate
of absorbency
Abstract
A softening composition, particularly useful for topical
treatment of tissues, comprises a polysiloxane, a fatty alkyl
derivative and glycerin. The softening composition provides good
softness to the tissue and enables the tissue to retain a high
degree of absorbency.
Inventors: |
Liu; Kou-Chang; (Appleton,
WI) |
Correspondence
Address: |
KIMBERLY-CLARK WORLDWIDE, INC.;Catherine E. Wolf
401 NORTH LAKE STREET
NEENAH
WI
54956
US
|
Family ID: |
39643835 |
Appl. No.: |
11/726588 |
Filed: |
March 22, 2007 |
Current U.S.
Class: |
162/179 ;
162/181.6; 252/8.63 |
Current CPC
Class: |
D21H 19/824 20130101;
D21H 19/82 20130101; D21H 19/32 20130101; D21H 19/14 20130101; D21H
27/005 20130101; D21H 19/20 20130101; D21H 21/22 20130101 |
Class at
Publication: |
162/179 ;
162/181.6; 252/8.63 |
International
Class: |
D21H 17/13 20060101
D21H017/13 |
Claims
1. A tissue softening composition comprising, based on the total
amount of actives in the composition, from about 5 to about 40
weight percent polysiloxane, from about 10 to about 50 weight
percent of an fatty alkyl derivative, from about 20 to about 80
weight percent glycerin.
2. The composition of claim 1 wherein the amount of polysiloxane is
from about 5 to about 30 weight percent.
3. The composition of claim 1 wherein the amount of polysiloxane is
from about 5 to about 20 weight percent.
4. The composition of claim 1 wherein the amount of fatty alkyl
derivative is from about 20 to about 50 weight percent.
5. The composition of claim 1 wherein the amount of fatty alkyl
derivative is from about 30 to about 50 weight percent.
6. The composition of claim 1 wherein the amount of glycerin is
from about 25 to about 80 weight percent.
7. The composition of claim 1 wherein the amount of glycerin is
from about 30 to about 80 weight percent.
8. The composition of claim 1 wherein the amount of glycerin is
from about 30 to about 70 weight percent.
9. The composition of claim 1 wherein the amount of polysiloxane is
from about 5 to about 20 weight percent, the amount of fatty alkyl
derivative is from about 20 to about 50 weight percent and the
amount of glycerin is from about 40 to about 70 weight percent.
10. A tissue sheet containing from about 0.2 to about 20 dry weight
percent, based on the dry weight of the tissue sheet, of a
topically applied softening composition, said softening composition
comprising, based on the total amount of actives in the
composition, from about 5 to about 50 weight percent polysiloxane,
from about 10 to about 50 weight percent of a fatty alkyl
derivative and from about 20 to about 80 weight percent
glycerin.
11. The tissue sheet of claim 10 wherein the amount of the
softening composition is from about 0.5 to about 5 dry weight
percent.
12. The tissue sheet of claim 10 wherein the amount of the
softening composition is from about 1 to about 2 dry weight
percent.
13. The tissue sheet of claim 10 having a Wet Out Time of about 20
seconds or less.
14. The tissue sheet of claim 10 having a Wet Out Time of from
about 3 to about 15 seconds.
15. The tissue sheet of claim 10 having a Wet Out Time of from
about 3 to about 10 seconds.
16. The tissue sheet of claim 10 wherein the amount of the
softening composition is from about 1 to about 2 dry weight
percent, wherein the amount of polysiloxane in the softening
composition is from about 5 to about 20 weight percent, the amount
of fatty alkyl derivative in the softening composition is from
about 30 to about 50 weight percent and the amount of glycerin in
the softening composition is from about 40 to about 70 weight
percent, said tissue sheet having a Wet Out Time of from about 3 to
about 10 seconds.
17. The tissue sheet of claim 16 having a geometric mean tensile
strength of from about 600 to about 1200 grams per 3 inches.
18. The tissue sheet of claim 16 having a geometric mean tensile
strength of from about 700 to about 1000 grams per 3 inches.
19. The tissue sheet of claim 16 having a geometric mean tensile
strength of from about 700 to about 900 grams per 3 inches.
20. A tissue sheet containing a topically applied softening
composition, said softening composition comprising, on a weight
percent basis, from about 20 to about 30 weight percent
polysiloxane and from about from about 20 to about 40 weight
percent glycerin.
21. The tissue sheet of claim 20 wherein the weight ratio of
polysiloxane:glycerin is from about 0.5 to about 1.4.
Description
BACKGROUND OF THE INVENTION
[0001] The use of polysiloxanes for treating tissues is well known
in the tissue industry. Polysiloxanes provide surface softness by
providing a slick feel to the tissue. Inherently, however,
polysiloxanes are relatively water repellant, such that the rate of
absorbency for the treated tissue is lessened. In addition,
polysiloxanes are relatively expensive. Consequently there is a
continual need for improved tissue softening compositions that not
only provide softness, but retain a satisfactory absorbent rate and
are cost effective.
SUMMARY OF THE INVENTION
[0002] Tissue softening compositions have been discovered which
cost effectively provide softness while retaining a good absorbent
rate (as measured by the Wet Out Time test, hereinafter
described).
[0003] Hence, in one aspect, the invention resides in a softening
composition particularly useful for topically treating tissues, the
composition comprising a polysiloxane, a fatty alkyl derivative and
glycerin. (For purposes herein, these three ingredients are
sometimes referred to as "actives".) Optional ingredients include
formulation aids and/or skin beneficial agents. More specifically,
the softening composition can contain, based on the total amount of
actives in the composition, from about 5 to about 40 weight percent
polysiloxane, from about 10 to about 50 weight percent of a fatty
alkyl derivative, from about 20 to about 80 weight percent
glycerin, and from 0 to about 10 weight percent formulation aids
and/or skin beneficial agents.
[0004] In another aspect, the invention resides in a tissue sheet
containing a topically applied softening composition, said
softening composition comprising, based on the total amount of
actives in the composition, from about 5 to about 40 weight percent
polysiloxane, from about 10 to about 50 weight percent of a fatty
alkyl derivative, from about 20 to about 80 weight percent glycerin
and from 0 to about 10 weight percent formulation aids and/or skin
beneficial agents.
[0005] In another aspect, the invention resides in a tissue sheet
containing a topically applied softening composition, said
softening composition comprising, on a weight percent basis, from
about 20 to about 30 weight percent polysiloxane and from about 20
to about 40 weight percent glycerin. More specifically, the weight
ratio of polysiloxane:glycerin can be from about 0.5 to about
1.4.
[0006] The amount of the softening composition actives in the
tissue can be, based on the dry weight of the tissue, from about
0.2 to about 20 weight percent, more specifically from about 0.2 to
about 10 weight percent, more specifically from about 0.5 to about
5 weight percent, and still more specifically from about 1 to about
3 weight percent.
[0007] The softening composition can be applied to the tissue sheet
in the form of a neat blend, an aqueous solution or an aqueous
emulsion. When applied as an aqueous solution or an aqueous
emulsion, the concentration of the softening composition in the
aqueous solution or aqueous emulsion can be from about 35 to about
80 weight percent, more specifically from about 40 to about 70
weight percent and still more specifically from about 45 to about
70 weight percent. Suitable methods of applying the softening
composition to the sheet, either directly or indirectly, include
printing or spraying.
[0008] The Wet Out Time for tissue sheets treated with the
softening compositions of this invention can be about 20 seconds or
less, more specifically about 15 seconds or less, more specifically
from about 3 to about 15 seconds and still more specifically from
about 3 to about 10 seconds.
[0009] The amount of polysiloxane in the softening composition,
based on the total amount of actives in the composition, can be
from about 5 to about 40 weight percent, more specifically from
about 5 to about 30 weight percent and still more specifically from
about 5 to about 20 weight percent.
[0010] Polysiloxanes useful for purposes of this invention can have
one or more pendant functional groups such as amine, quaternium,
aldehyde, epoxy, hydroxy, alkoxyl, polyether and carboxylic acid
and its derivatives, such as amides and esters. Particularly
suitable polysiloxanes have the following general structure:
##STR00001##
wherein: [0011] "m" is from 10 to 100,000; [0012] "n" is from 1 to
10,000; [0013] "p" is from 0 to 1,000; [0014] "A" and "B" are
independently a hydroxyl, C.sub.1 to C.sub.20 or R.sub.2; [0015]
R.sub.1, R.sub.2 and R.sub.3 are distributed in random or block
fashion; [0016] R.sub.1 is a C.sub.1 to C.sub.8 radical, which can
be straight chain, branched or cyclic; [0017] R.sub.2 is a C.sub.1
to C.sub.8 radical, which can be straight chain, branched or
cyclic, or of the structure:
##STR00002##
[0018] wherein
[0019] R.sub.4 and R.sub.5 are independently a C.sub.2 to C.sub.8
alkylene diradical, which can be straight chain or branched,
substituted, or unsubstituted;
[0020] X is an oxygen or N--R.sub.8;
[0021] R.sub.6, R.sub.7 and R.sub.8 are independently hydrogen, a
substituted or unsubstituted C.sub.1 or C.sub.2, a substituted or
unsubstituted straight chain or branched or cyclic C.sub.3 to
C.sub.20 alky radical, or an acyl radical, such as an acetyl
radical; and
[0022] "s" is 0 or 1;
R.sub.3 is of the structure:
R.sub.9--Y--[C.sub.2H.sub.4O].sub.r--[C.sub.3H.sub.6O].sub.q--R.sub.10
[0023] wherein
[0024] Y is an oxygen or N--R.sub.11;
[0025] R.sub.9 is a C.sub.2 to C.sub.8 alkylene diradical, which
can be straight chain or branched, substituted or
unsubstituted;
[0026] R.sub.10 and R.sub.11 are independently hydrogen, a
substituted or unsubstituted C.sub.1 or C.sub.2, a substituted or
unsubstituted, straight chain or branched or cyclic C.sub.3 to
C.sub.20 alkyl radical;
[0027] "r" is from 1 to 100,000; and
[0028] "q" is from 0 to 100,000.
When R.sub.2.dbd.R.sub.1, "A" and "B" can also be a nitrogen
quarternium.
[0029] Examples of suitable commercially available polysiloxanes
include AF-2340, AF-2130, AF-23, HAF-1130, EAF-3000, EAF-340,
EAF-15, AF-2740, WR-1100, WR-1300 and Wetsoft CTW from
Kelmar/Wacker; DC-8822, DC-8566, DC-8211, DC-SF8417, DC-2-8630,
DC-NSF, DC-8413, DC-SSF, DC-8166 from Dow Corning; SF-69, SF-99
SF-1023 from GE Silicones and Tegopren 6924, Tegopren 7990, Tego
IS4111 from Goldschmidt/Degussa.
[0030] The amount of fatty alkyl derivative in the softening
composition, based on the total amount of actives in the
composition, can be from about 10 to about 50 weight percent, more
specifically from about 20 to about 50 weight percent and still
more specifically from about 30 to about 50 weight percent.
[0031] Fatty alkyl derivatives particularly suitable for purposes
of this invention can have the following general structure:
R.sub.14-G
wherein:
[0032] R.sub.14 is a C.sub.8 to C.sub.40 alkyl radical, which can
be substituted or unsubstituted, primary, secondary or tertiary;
straight chain, branched or cyclic; and
[0033] "G" is hydroxy, amine, sulfonate, sulfate, phosphate, acid
or acid derivative, or -Q-[C.sub.2H.sub.4O
].sub.l--[C.sub.3H.sub.6O].sub.j--[C.sub.tH.sub.2tO].sub.v--R.sub.13
radical;
[0034] wherein
[0035] "Q" is an oxygen radical, an NH radical or
N--[C.sub.2H.sub.4O}.sub.l--[C.sub.3H.sub.6O].sub.j--[C.sub.tH.sub.2tO].s-
ub.v--R.sub.13 radical;
[0036] R.sub.13 is a hydrogen, a substituted or unsubstituted
C.sub.1 to C.sub.6 alkyl radical, a straight chain or branched
C.sub.1 to C.sub.6 alkyl radical, or a cyclic C.sub.1 to C.sub.6
alkyl radical;
[0037] "i", "j" and "v" are independently from 0 to 100,000, where
the oxide moieties are distributed along the polymer backbone
randomly or as blocks;
[0038] "i+j+v" is equal to or greater than 10; and
[0039] "t" is from 4 to 10.
[0040] Examples of suitable fatty alkyl derivatives are 9-EO
ethoxylated tridecylalcohol; Ceteth-10; Ceteth-12 (12-EO
ethoxylated cetyl alcohol); Ceteth-20; Pluraface A-38, Macol CSA 20
and Macol LA 12 from BASF; Armeen 16D, Armeen 18D, Armeen HTD,
Armeen 2C, Armeen M2HT, Armeeh 380, Ethomeen 18/15 Armid O,
Witconate 90, Witconate AOK, and Witcolate C from Akzo Nobel and
Tergitol 15-S-9, Tergitol 15-S-7, Tergitol 15-S-12, Tergitol TMN-6,
Tergitol TMN-10, Tergitol XH, Tergitol XDLW, and Tergitol RW-50
from Dow Chemical.
[0041] The amount of glycerin in the softening composition can be,
based on the total amount of actives in the composition, from about
20 to about 80 weight percent, more specifically from about 25 to
about 80 weight percent, more specifically from about 30 to about
80 weight percent and still more specifically from about 40 to
about 70 weight percent.
[0042] Suitable formulation aids include, without limitation,
emulsifiers, co-solvent, anti-foaming agents and preservatives.
Suitable skin beneficial agents include, without limitation, aloe,
vitamin-E, chamomile and .alpha.-hydroxy acids.
[0043] The "Wet Out Time" of a tissue sheet treated in accordance
with the present invention is determined by cutting 20 sheets of
the tissue sheet sample into 2.5 inch squares. The number of sheets
of the tissue sheet sample used in the test is independent of the
number of plies per sheet of the tissue sheet sample. The 20 square
sheets of the tissue sheet sample are stacked together and stapled
at each corner to form a pad of the tissue sheet sample. The pad of
the tissue sheet sample is held close to the surface of a constant
temperature distilled water bath (23.degree. C..+-.2.degree. C.),
which is the appropriate size and depth to ensure the saturated pad
of the tissue sheet sample does not contact the bottom of the water
bath container and the top surface of the distilled water of the
water bath at the same time, and dropped flat onto the surface of
the distilled water, with staple points on the pad of the tissue
sheet sample facing down. The time necessary for the pad of the
tissue sheet sample to become completely saturated, measured in
seconds, is the Wet Out Time for the tissue sheet sample and
represents the absorbent rate of the tissue sheet sample. Increases
in the Wet Out Time represent a decrease in absorbent rate of the
tissue sheet sample.
[0044] For purposes herein, the term "tissue" means a paper sheet
having a bulk of about 2 cm.sup.3 or greater/ gram, more
specifically about 2.5 cm.sup.3 or greater/ gram and still more
specifically about 3 cm.sup.3 or greater/gram. Such sheets are
particularly useful for facial tissue, bath tissue and paper towels
and can be made by any method well known to those skilled in the
tissue arts. The bulk is calculated as the quotient of the caliper
(hereinafter defined), expressed in microns, divided by the basis
weight, expressed in grams per square meter. The resulting bulk is
expressed as cubic centimeters per gram. The term "caliper" as used
herein is the thickness of a single tissue sheet, and may either be
measured as the thickness of a single tissue sheet or as the
thickness of a stack of ten tissue sheets and dividing the ten
tissue sheet thickness by ten, where each sheet within the stack is
placed with the same side up. Caliper is expressed in microns and
can be measured in accordance with TAPPI test methods T402
"Standard Conditioning and Testing Atmosphere For Paper, Board,
Pulp Handsheets and Related Products" and T411 om-89 "Thickness
(caliper) of Paper, Paperboard, and Combined Board" optionally with
Note 3 for stacked tissue sheets. The micrometer used for carrying
out T411 om-89 is a Bulk Micrometer (TMI Model 49-72-00,
Amityville, N.Y.) or equivalent having an anvil diameter of 4 1/16
inches (103.2 millimeters) and an anvil pressure of 220
grams/square inch (3.3 g kilo Pascals).
[0045] As used herein, the term "dry" weight percent in reference
to a composition or tissue sheet containing a composition means
that the amount of free water or other volatile components in the
composition or tissue product are ignored. Stated differently, the
"dry" weight percent is intended to represent the amount of "active
components" in the composition. Therefore, for tissue sheets, all
recited dry weight percent amounts refer to tissue sheets that have
been aged for at least three (3) weeks and therefore have
equilibrated with ambient conditions. The dry weight percent
amounts can be determined by chemical extraction and analysis of
the extract or, if the conditioned basis weight of the tissue sheet
prior to treatment is known, by subtracting the conditioned basis
weight of the untreated tissue from the conditioned basis weight of
the treated tissue and dividing the difference by the conditioned
basis weight of the treated tissue and multiplying by 100.
[0046] As used herein, the "geometric mean tensile strength" (GMT)
is the square root of the product of the dry machine direction
tensile strength multiplied by the dry cross-machine direction
tensile strength and is expressed as grams per 3 inches of sample
width. The machine direction tensile strength is the peak load per
3 inches of sample width when a sample is pulled to rupture in the
machine direction. Similarly, the cross-machine direction (CD)
tensile strength is the peak load per 3 inches of sample width when
a sample is pulled to rupture in the cross-machine direction. More
specifically, samples for tensile strength testing are prepared by
cutting a 3 inches (76.2 mm) wide by 5 inches (127 mm) long strip
in either the machine direction (MD) or cross-machine direction
(CD) orientation using a JDC Precision Sample Cutter (Thwing-Albert
Instrument Company, Philadelphia, Pa., Model No. JDC 3-10, Serial
No. 37333). The instrument used for measuring tensile strengths is
an MTS Systems Sintech 11S, Serial No. 6233. The data acquisition
software is MTS TestWorks.RTM. for Windows Ver. 3.10 (MTS Systems
Corp., Research Triangle Park, N.C.). The load cell is selected
from either a 50 Newton or 100 Newton maximum, depending on the
strength of the sample being tested, such that the majority of peak
load values fall between 10-90% of the load cell's full scale
value. The gauge length between jaws is 4.+-.0.04 inches
(101.6.+-.1 mm). The jaws are operated using pneumatic-action and
are rubber coated. The minimum grip face width is 3 inches (76.2
mm), and the approximate height of a jaw is 0.5 inches (12.7 mm).
The crosshead speed is 10.+-.0.4 inches/min (254.+-.1 mm/min), and
the break sensitivity is set at 65%. The sample is placed in the
jaws of the instrument, centered both vertically and horizontally.
The test is then started and ends when the specimen breaks. The
peak load is recorded as either the "MD tensile strength" or the
"CD tensile strength" of the specimen depending on direction of the
sample being tested. At least six (6) representative specimens are
tested for each product or sheet, taken "as is", and the arithmetic
average of all individual specimen tests is either the MD or CD
tensile strength for the product or sheet.
[0047] The geometric mean tensile strength of the products of this
invention can be, without limitation, from about 600 to about 1200
grams per 3 inches, more particularly from about 700 to about 1000
grams per 3 inches and still more specifically from about 700 to
about 900 grams per 3 inches.
[0048] In the interests of brevity and conciseness, any ranges of
values set forth in this specification are to be construed as
written description support for claims reciting any sub-ranges
having endpoints which are whole number values within the specified
range in question. By way of a hypothetical illustrative example, a
disclosure in this specification of a range of from 1 to 5 shall be
considered to support claims to any of the following sub-ranges:
1-4; 1-3; 1-2; 2-5; 2-4; 2-3; 3-5; 3-4 and 4-5.
BRIEF DESCRIPTION OF THE DRAWINGS
[0049] FIG. 1 is a plot of the results of Example 1 from Table 2,
illustrating the softness as a function of the glycerin percentage
in the formulation containing polysiloxane and glycerin. As shown,
softness peaks at about 35 weight percent glycerin and then falls
off significantly as the percentage of glycerin is increased.
[0050] FIG. 2 is a plot of the results of Example 3 from Table 6,
illustrating the softness as a function of strength for various
glycerin amounts in the formulation containing polysiloxane, fatty
alkyl derivative and glycerin. As shown, softness peaks at about 33
weight percent glycerin.
EXAMPLES
[0051] For purposes of the following examples, tissue basesheets
for use in accordance with this invention were either wet-pressed
creped tissue sheets or uncreped throughdried tissue sheets. The
wet-pressed tissue sheets were converted into three-ply facial
tissue treated products and the uncreped throughdried tissue sheets
were converted into single-ply bath tissue treated products for
testing. After the tissue products were made, they were tested for
geometric mean tensile strength, wettability (Wet Out Time,
described above) and softness. The tissue sheets were made as
described below.
Wet-Pressed Tissue Sheets
[0052] In general, these tissue basesheets were produced using a
conventional wet-pressed tissue making process well known in the
art. More particularly, an aqueous suspension of papermaking fibers
was issued from a layered headbox onto a forming fabric. The
furnish consisted of 70 weight percent hardwood (eucalyptus) fibers
and 30 weight percent softwood fibers. A vacuum box beneath forming
fabric was adapted to remove water from the fiber furnish to assist
in forming a web. The newly formed web was transferred to a felt
with aid of a pick up roll. While supported by the felt, the tissue
web was lightly pressed onto the surface of a Yankee dryer using a
press roll. The dried web was creped from the surface of the Yankee
dryer and the resulting single-ply tissue basesheet was wound onto
a parent roll. Thereafter, the basesheets from three like parent
rolls were unwound and converted into a three-ply basesheet for
subsequent application of the various softening compositions. The
finished basis weight of the three-ply basesheet was about 22.7
pounds per 2880 square feet.
[0053] The softening composition was simultaneously appied to both
surfaces of the three-ply basesheet by rotogravure printing. The
gravure rolls were electronically engraved, chrome over copper
rolls supplied by Southern Graphics Systems, located at Louisville,
Ky. The rolls had a line screen of 360 cells per lineal inch and a
volume of 1.5 Billion Cubic Microns (BCM) per square inch of roll
surface. Typical cell dimensions for this roll were 65 microns in
length, 110 microns in width, and 13 microns in depth. The rubber
backing offset applicator rolls were a 75 Shore A durometer cast
polyurethane supplied by American Roller Company, located at Union
Grove, Wis. The process was set up to a condition having 0.375 inch
interference between the gravure rolls and the rubber backing rolls
and 0.003 inch clearance between the facing rubber backing rolls.
The simultaneous offset/offset gravure printer was run at a speed
of 2000 feet per minute. This process yielded a solids add-on level
of about 1.0 weight percent based on the dry weight of the finished
tissue product. (0.5 dry weight percent on each side of the
product.
Uncreped Throughdried Tissue Sheets
[0054] Single-ply, three-layered uncreped throughdried bath tissue
basesheets were made generally in accordance with the following
procedure using eucalyptus pulp fibers for the outer layers and
softwood pulp fibers for the inner layer. Prior to pulping, a
quaternary ammonium oleylimidazoline softening agent (Prosoft
TQ-1003 from Hercules, Inc.) was added at a dosage of 4.1 kg/Mton
of active chemical per metric ton of pulp fiber to the eucalyptus
furnish. After allowing 20 minutes of mixing time, the furnish was
dewatered using a belt press to approximately 32% consistency. The
filtrate from the dewatering process was either sewered or used as
pulper make-up water for subsequent pulp fiber batches but not sent
forward in the stock preparation or tissue making process. The
thickened pulp fiber containing the debonder was subsequently
redispersed in water and used as the outer layer furnishes in the
tissue making process. The softwood pulp fibers were pulped for 30
minutes at 4 percent consistency and diluted to about 3.2 percent
consistency after pulping, while the debonded eucalyptus pulp
fibers were diluted to about 2 percent consistency. The overall
layered tissue sheet weight was split about 30%/about 40%/about 30%
among the eucalyptus/refined softwood/eucalyptus pulp fiber layers.
The center layer was refined to levels required to achieve target
strength values, while the outer layers provided the surface
softness and bulk.
[0055] A three-layered headbox was used to form the wet tissue
sheet with the refined northern softwood kraft stock in the two
center layers of the head box to produce a single center layer for
the three-layered tissue product described. Turbulence-generating
inserts recessed about 3 inches (75 millimeters) from the slice and
layer dividers extending about 1 inch (25.4 millimeters) beyond the
slice were employed. The net slice opening was about 0.9 inch (23
millimeters) and water flows in all four headbox layers were
comparable. The consistency of the stock fed to the headbox was
about 0.09 weight percent. The resulting three-layered tissue sheet
was formed on a twin wire, suction form roll, former with forming
fabrics being Lindsay 2164 and Asten 867A fabrics, respectively.
The speed of the forming fabrics was 11.9 meters per second. The
newly-formed tissue sheet was then dewatered to a consistency of
about 20 to about 27 percent using vacuum suction from below the
forming fabric before being transferred to the transfer fabric,
which was traveling at about 9.1 meters per second (30% rush
transfer). The transfer fabric was an Appleton Wire T807-1. A
vacuum shoe pulling about 6-15 inches (150-380 millimeters) of
mercury vacuum was used to transfer the tissue sheet to the
transfer fabric. The tissue sheet was then transferred to a
throughdrying fabric (Lindsay Wire T1205-1). The throughdrying
fabric was traveling at a speed of about 9.1 meters per second. The
tissue sheet was carried over a Honeycomb throughdryer operating at
a temperature of about 350.degree. F. (175.degree. C.) and dried to
final dryness of about 94-98 percent consistency. The resulting
uncreped tissue sheet was then wound into a parent roll.
[0056] The parent roll was then unwound and the tissue sheet was
calendered twice. At the first station the tissue sheet was
calendered between a steel roll and a rubber covered roll having a
4 P&J hardness. The calender loading was about 90 pounds per
lineal inch (pli). At the second calendering station, the tissue
sheet was calendered between a steel roll and a rubber covered roll
having a 40 P&J hardness. The calender loading was about 140
pli. The thickness of the rubber covers was about 0.725 inch (1.84
centimeters).
[0057] The calendered single-ply tissue sheet was then fed into the
rubber-rubber nip of the rotogravure coater to apply the softness
composition to both sides of the tissue sheet. The gravure rolls
were electronically engraved, chrome over copper rolls supplied by
Specialty Systems, Inc., located at Louisville, Ky. The rolls had a
line screen of 200 cells per lineal inch and a volume of 6.0
Billion Cubic Microns (BCM) per square inch of roll surface.
Typical cell dimensions for this roll were 140 microns in width and
33 microns in depth using a 130 degree engraving stylus. The rubber
backing offset applicator rolls were a 75 Shore A durometer cast
polyurethane supplied by American Roller Company, located at Union
Grove, Wis. The process was set up to a condition having 0.375 inch
interference between the gravure rolls and the rubber backing rolls
and 0.003 inch clearance between the facing rubber backing rolls.
The simultaneous offset/offset gravure printer was run at a speed
of 500 feet per minute using gravure roll speed adjustment
(differential) to meter the polysiloxane emulsion to obtain the
desired addition rate. The gravure roll speed differential used for
this example was 500 feet per minute. This process yielded an
add-on level of 2.0 weight percent total solids add-on based on the
weight of the tissue. The tissue sheet was then converted into bath
tissue rolls.
[0058] The softness and stiffness of the tissue products were
determined by a trained in-hand ranking panel, which provides a
basic assessment of the softness and stiffness characteristics of a
tissue product. The ranking panel is trained to provide holistic
assessments as close as possible to those that a typical consumer
might provide. In carrying out the test for the three-ply tissue
products, three different assessments are made: "Softness",
"Softness-on-Face" and "Stiffness". The Softness test involves
evaluating the velvety, silky or fuzzy feel of the tissue sample
when rubbed between the thumb and fingers. The Softness-on-Face
test involves rubbing the tissue sample against the face, including
the area between the nose and lips. The Stiffness test involves
gathering a flat sample into one's hand and moving the sample
around in the palm of the hand by drawing the fingers toward the
palm and evaluating the amount of pointed, rigid or cracked edges
or peaks felt. Rank data generated for each sample code by the
panel are analyzed using a proportional hazards regression model.
This model assumes computationally that the panelist proceeds
through the ranking procedure from most of the attribute being
assessed to least of the attribute. The softness and stiffness test
results are presented in the tables below as log odds values. The
log odds are the natural logarithm of the risk ratios that are
estimated for each code from the proportional hazards regression
model. Larger log odds indicate the attribute of interest is
perceived with greater intensity.
Example 1
[0059] Tissue softening formulations containing various amounts of
a polysiloxane (AF-2340) and glycerin were prepared. AF-2340 is an
aqueous emulsion of an aminopolysiloxane which contains about 35
weight percent of an aminopolysiloxane fluid and formulation aids.
The relative weight percent amounts of the polysiloxane emulsion
(AF2340) and the glycerin in the various formulations are set forth
in Table 1. Uncreped throughdried tissue product samples were
prepared as described above by gravure coating the formulations
onto both surfaces of a single-ply tissue basesheet. A total
actives add-on of 2 dry weight percent (1 dry weight percent on
each side) was evenly coated on both sides of the basesheet. The
treated basesheets were then converted into bath tissue rolls and
tested for softness and absorbency. The results of the testing are
set forth in Table 2 and plotted in FIG. 1.
TABLE-US-00001 TABLE 1 Polysiloxane emulison (AF2340) Glycerin
(weight (weight Water and other formulation Formulation percent)
percent) aids balance to 100% 1 100% 0% '' 2 80% 20% '' 3 60% 40%
'' 4 40% 60% '' 5 20% 80% '' 6 0% 80% ''
TABLE-US-00002 TABLE 2 GMT WOT Softness* Stiffness** Formulation
(grams) (seconds) (Log odds) (Log odds) 1 713 19.9 BC (0.0000) CD
(0.0000) 2 701 25.6 AB (0.2510) D (0.1421) 3 695 26.0 AB (0.2709)
DE (0.2677) 4 714 22.6 C (-0.1609) C (0.2630) 5 744 24.8 D
(-0.6376) B (1.0242) 6 760 4.0 E (-3.7391) A (2.4454) *"A'' is
significantly softer than "B'', but only directionally softer than
"AB''. "AB'' is softer than "C'', etc. Higher positive numbers
correlate with greater softness. Larger negative numbers correlate
with lower soffness. Hence higher numbers are more desirable.
**"A'' is significantly stiffer than "B'', but only directionally
stiffer than "AB''. "AB is stiffer than "C'', etc. Higher positive
numbers correlate with greater stiffness. Larger negative numbers
correlate with lower sstiffness. Since stiffness is generally
undesirable for a soft product, lower numbers are more
desirable.
[0060] The results, as further illustrated in FIG. 1, show that
AF-2340 polysilxane is an excellent tissue softening chemical,
while glycerin is significantly less effective. Furthermore,
Formulation 2 (containing 20 weight percent glycerin and 80 weight
percent polysiloxane emulsion (28 dry weight percent polysiloxane))
and Formulation 3 (containing 40 weight percent glycerin and 60
weight percent polysiloxane emulsion (21 dry weight percent
polysiloxane)) unexpectedly provided the treated tissues with
softer handfeel than those treated by either glycerin or
polysiloxane alone, illustrating a synergistic effect when the
polysiloxane:glycerin weight ratio is from about 0.5 to 1.4 and the
absolute level of glycerin is from about 20 to about 40 weight
percent.
Example 2
[0061] Tissue softening formulations were prepared based on a
polysiloxane (AF-23), a fatty alkyl derivative (Tergitol 15-S-9)
and glycerin. AF-23 is an aminopolysiloxane from Wacker Chemical
and Tergitol 15-S-9 is a fatty alkyl derivative from Dow Chemical.
The relative weight percent amounts of the polysiloxane, the fatty
alkyl derivative and glycerin in the formulations are set forth in
Table 3. (Note that the weight percentage amounts are for the
formulation, which contains water, as opposed to the relative
amounts of the actives that will ultimately be present on the
treated tissue.) Facial tissue product samples were prepared as
described above by gravure coating the various formulations on both
sides of a three-ply, wet-pressed, creped tissue basesheet. A total
actives add-on of 1 dry weight percent (0.5 dry weight percent on
each side) was evenly coated on both sides of the basesheet. The
treated basesheets were then converted into folded facial tissue
products and tested for softness and absorbency. The test results
are set forth in Table 4.
TABLE-US-00003 TABLE 3 Fatty Alkyl Polysiloxane Derivative Glycerin
Water and other (weight (weight (weight formulation aids
Formulation percent) percent) percent) balance to 100% 1 (Control)
35% 0% 0% '' 2 (Invention) 6% 18% 20% '' 3 (Invention) 9% 15% 20%
''
TABLE-US-00004 TABLE 4 Softness WOT on Face Softness Stiffness
Formulation GMT (grams) (seconds) (Log odds) (Log odds) (Log odds)
1 (control) 895 14.7 B E (-1.4762) BCD (0.0754) (-0.6321) 2
(Invention) 969 6.2 A (0.1515) CD (-0.4977) D (-.00354) 3
(Invention) 958 8.7 A (0.0928) A (0.8301) D (-0.0953)
[0062] The results illustrate that although AF-2340 polysilxane is
an excellent tissue softening chemical, the compositions of this
invention (Formulations 2 and 3) are more effective while also
providing improved wettability (lower Wet Out Times).
Example 3
[0063] Tissue softening formulations containing various amounts of
a polysiloxane (AF-2340), a fatty alkyl derivative (Tergitol
15-S-9) and glycerin were prepared. AF-2340 is an aqueous emulsion
of an aminopolysiloxane which contains about 35 weight percent of
an aminopolysiloxane fluid (AF-23) and formulation aids. The
amounts of the polysiloxane, the fatty alkyl derivative and
glycerin in the formulations are set forth in Table 5. Tissue
samples were prepared as described above by gravure coating the
formulations on a 1-ply uncreped throughdried tissue basesheet. A
total actives add-on of 2 dry weight percent (1 dry weight percent
on each side) was evenly coated on both sides of the basesheet. The
treated basesheets were then converted into rolled bath tissue and
tested for softness and absorbency. The test results are set forth
in Table 6 and further illustrated in FIG. 2.
TABLE-US-00005 TABLE 5 Fatty Alkyl Polysiloxane Derivative Glycerin
Water and other (weight (weight (weight formulation aids
Formulation percent) percent) percent) balance to 100% 1 (Control)
7.5% 22.5% 0% '' 2 (Invention) 6.25% 18.7% 16.7% '' 3 (Invention)
5.0% 15.0% 33.3% '' 4 (Invention) 3.8% 11.2% 50% ''
TABLE-US-00006 TABLE 6 GMT WOT Softness Stiffness Formulation
(grams) (seconds) (Log odds) (Log odds) 1 (Control) 617 4.4 CD
(0.5805) A (0.0000) 2 (Invention) 678 4.3 BC (0.9033) DE (-0.9016)
3 (Invention) 701 4.3 AB (1.2924) AB (-0.1403)) 4 (Invention) 740
4.8 BC (0.8915) ABCD (-0.5289)
[0064] These results further illustrate that softness compositions
of this invention containing a blend of polysiloxane, a fatty alkyl
derivative and glycerin at a proper ratio can provide treated
tissue products with excellent softness, handfeel, good wettability
and strength.
[0065] It will be appreciated that the foregoing description and
examples, given for purposes of illustration, is not to be
construed as limiting the scope of the invention, which is defined
by the following claims and all equivalents thereto.
* * * * *