Soft absorbent tissue

Details Soft absorbent tissue Soft absorbent tissue

2001-02-20

2002-08-13

Dawson, Robert (Department: 1712)

Paper making and fiber liberation

Processes and products

Non-fiber additive

C106S287110, C162S112000, C162S118000, C162S127000, C428S447000, C428S452000, C442S118000, C528S038000

Reexamination Certificate

active

06432270

ABSTRACT:

BACKGROUND OF THE INVENTION
In the field of soft tissues, such as facial tissue and bath tissue, it is well known that the application of polysiloxanes to the surface of the tissue can impart an improved surface feel to the tissue. However, polysiloxanes are also known to impart hydrophobicity to the treated tissue. Hence it is difficult to find a proper balance between softness and absorbency, both of which are desirable attributes for tissue, particularly bath tissue.
SUMMARY OF THE INVENTION
It has now been discovered that the softness of a tissue can be improved with minimal negative impact on the absorbency or wettability of the tissue by treating one or both outer surfaces of the tissue with a particular group of hydrophilically-modified amino-functional polydiorganosiloxanes. More specifically, suitable polysiloxane structures have one or more pendant groups which contain a terminal amine and at least one ethylene oxide moiety. The terminal amine group and the ethylene oxide moieties can be parts of the same pendant group or different pendant groups. A general structure is as follows:
wherein:
X is hydrogen, hydroxy, amino, C
1
-C
8
straight chain, branched, cyclic, unsubstituted or hydrophilically substituted alkyl or alkoxyl radical;
m=20-100,000;
p=1-5000;
q=0-5000;
R
1
=a C
1
-C
6
, straight chain, branched or cyclic alkyl radical;
R
2
=a C
1
-C
10
straight chain or branched, substituted or unsubstituted alkylene diradical;
R
3
=—R
5
—(CH
2
-CH
2
—O)
r
—(CH
2
-CH—O)
s
—Z
wherein
R
5
is an unsubstituted or a hydrophilically substituted C
1
-C
10
alkylene diradical;
r=1-10,000;
s=0-10,000; and
Z=hydrogen, C
1
-C
24
alkyl group, or a G-group, where G is selected from the following: —R
6
COOR
7
; —CONR
8
R
9
; —SO
3
R
8
; and PO R
8
R
9
, where R
6
is a substituted or unsubstituted C
1
-C
6
alkylene diradical; R
7
, R
8
, and R
9
are independently a hydrogen radical or a substituted or unsubstituted C
1
-C
8
alkyl radical; and
wherein
R
10
, R
11
, and R
12
are independently an unsubstituted or a hydrophilically substituted C
1
-C
8
alkylene diradical;
t=0-10,000;
u=0-10,000;
w=0-10,000; and
R
13
, R
14
and R
15
are independently a hydrogen radical, an unsubstituted or a hydroxyl, carboxyl or other functionally substituted C
1
-C
10
straight chain, branched, or cyclic alkyl radical.
Representative species within the foregoing general structure include the following (the values of “m”, “p” and “q” are as defined above; the terms “EO” and “PO” are shorthanded representations of “ethylene oxide” and “propylene oxide” moieties, respectively):
The hydrophilically-modified amino-functional polydiorganosiloxanes described above can be applied to the tissue web alone or in conjunction with other chemicals, such as bonders or debonders. They can be applied to the tissue web, particularly an uncreped throughdried web, by spraying or printing. Rotogravure printing of an aqueous emulsion is particularly effective. Add-on amounts can be from about 0.5 to about 15 dry weight percent, based on the weight of the tissue, more specifically from about 1 to about 10 dry weight percent, still more specifically from about 1 to about 5 weight percent, still more specifically from about 2 to about 5 weight percent. The distribution of the deposits of the hydrophilically-modified amino-functional polydiorganosiloxanes is substantially uniform over the printed surface of the tissue, even though the surface of the tissue, such as in the case of uncreped throughdried tissues, may be highly textured and three-dimensional. The printing does limit the deposits to the high points of the textured tissue sheets, thereby ensuring a soft hand feel.
The Wet Out Time (hereinafter defined) for tissues of this invention can be about seconds or less, more specifically about 8 seconds or less, still more specifically about seconds or less, still more specifically about 5 seconds or less, still more specifically from about 4 to about 6 seconds. As used herein, “Wet Out Time” is related to absorbency and is the time it takes for a given sample to completely wet out when placed in water. More specifically, the Wet Out Time is determined by cutting 20 sheets of the tissue sample into 2.5 inch squares. The number of sheets used in the test is independent of the number of plies per sheet of product. The 20 square sheets are stacked together and stapled at each corner to form a pad. The pad is held close to the surface of a constant temperature distilled water bath (23+/−2° C.), which is the appropriate size and depth to ensure the saturated specimen does not contact the bottom of the container and the top surface of the water at the same time, and dropped flat onto the water surface, staple points down. The time taken for the pad to become completely saturated, measured in seconds, is the Wet Out Time for the sample and represents the absorbent rate of the tissue. Increases in the Wet Out Time represent a decrease in absorbent rate.
The “Differential Wet Out Time” is the difference between the Wet Out Times of a tissue sample treated with a hydrophilically-modified amino-functional polydiorganosiloxane and a control tissue sample which has not been treated. The Differential Wet Out Time, for purposes of this invention, can be about 5 seconds or less, more specifically about 4 seconds or less, still more specifically about 3 seconds or less, still more specifically about 2 seconds or less, and still more specifically about 1 second or less.
The ratio of the Wet Out Time, expressed in seconds, to the add-on amount of the hydrophilically-modified amino-functional polydiorganosiloxane in the tissue, expressed as dry weight percent of the weight of the tissue, can be about 3 seconds per weight percent or less, more specifically about 2 seconds per weight percent or less, still more specifically from about 1 to about 3 seconds per weight percent.
The ratio of the Differential Wet Out Time to the add-on amount of the hydrophilically-modified amino-functional polydiorganosiloxane can be about 2 seconds per weight percent or less, more specifically about 1 second per weight percent or less, still more specifically about 0.5 second per weight percent or less.
Tissue sheets useful for purposes of this invention can be creped or uncreped. Such tissue sheets can be used for facial tissues or bath tissues. They can have one, two, three or more plies. The basis weight of the tissue product can be from about 25 to about 50 grams per square meter. If used for bath tissue, a single ply tissue having a basis weight of from about 30-40 grams per square meter is particularly suitable.


REFERENCES:
patent: 4409267 (1983-10-01), Ichinohe et al.
patent: 4614675 (1986-09-01), Ona et al.
patent: 4938832 (1990-07-01), Schmalz
patent: 4963432 (1990-10-01), Fuggini et al.
patent: 5059282 (1991-10-01), Ampulski et al.
patent: 5078747 (1992-01-01), Kästele et al.
patent: 5098979 (1992-03-01), O'Lenick, Jr.
patent: 5164046 (1992-11-01), Ampulski et al.
patent: 5215626 (1993-06-01), Ampulski et al.
patent: 5246546 (1993-09-01), Ampulski
patent: 5281658 (1994-01-01), Ona et al.
patent: 5385643 (1995-01-01), Ampulski
patent: 5389204 (1995-02-01), Ampulski
patent: 5399612 (1995-03-01), Calhoun
patent: 5409620 (1995-04-01), Kosal et al.
patent: 5518775 (1996-05-01), Kosal et al.
patent: 5538595 (1996-07-01), Trokhan et al.
patent: 5552020 (1996-09-01), Smith et al.
patent: 5567347 (1996-10-01), Kosal et al.
patent: 5573637 (1996-11-01), Ampulski et al.
patent: 5575891 (1996-11-01), Trokhan et al.
patent: 5629088 (1997-05-01), Ogawa et al.
patent: RE35621 (1997-10-01), Schmalz
patent: 5707434 (1998-01-01), Halloran et al.
patent: 5707435 (1998-01-01), Halloran
patent: 5716704 (1998-02-01), Ogawa et al.
patent: 5725736 (1998-03-01), Schroeder et al.
patent: 5807956 (1998-09-01), Czech
patent: 5814188 (1998-09-01), Vinson et al.
patent: 5925469 (1999-07-01), Gee
patent: 5944273 (1999-08-01), Lin et al.
patent: 5981681 (1999-11-01), C

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