U.S. patent application number 10/156256 was filed with the patent office on 2003-04-17 for wet-laid absorbent pulp sheet suitable for immediate conversion into an absorbent product.
This patent application is currently assigned to Rayonier Inc.. Invention is credited to Byers, Erin M., Crow, Anne B..
Application Number | 20030070776 10/156256 |
Document ID | / |
Family ID | 24000538 |
Filed Date | 2003-04-17 |
United States Patent
Application |
20030070776 |
Kind Code |
A1 |
Crow, Anne B. ; et
al. |
April 17, 2003 |
Wet-laid absorbent pulp sheet suitable for immediate conversion
into an absorbent product
Abstract
Wet-laid absorbent pulp sheets suitable for immediate conversion
into absorbent products prepared from pulp treated with a cold
caustic solution to produce a cold caustic extracted pulp.
Inventors: |
Crow, Anne B.; (Olympia,
WA) ; Byers, Erin M.; (Stamford, CT) |
Correspondence
Address: |
William J. Spatz, Esq.
Kramer Levin Naftalis & Frankel LLP
919 Third Avenue
New York
NY
10022
US
|
Assignee: |
Rayonier Inc.
|
Family ID: |
24000538 |
Appl. No.: |
10/156256 |
Filed: |
May 28, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10156256 |
May 28, 2002 |
|
|
|
08503043 |
Jul 17, 1995 |
|
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Current U.S.
Class: |
162/9 ; 162/100;
162/13; 162/157.6; 162/90 |
Current CPC
Class: |
A61F 13/53 20130101;
D21C 9/004 20130101; C08L 1/00 20130101; C08L 1/00 20130101; A61F
13/00 20130101; A61L 15/28 20130101; A61F 2013/15406 20130101; A61F
13/537 20130101; A61F 2013/15463 20130101; A61L 15/28 20130101;
A61L 15/28 20130101 |
Class at
Publication: |
162/9 ; 162/90;
162/13; 162/100; 162/157.6 |
International
Class: |
D21C 003/02; D21H
011/16; D21H 011/18 |
Claims
What is claimed is:
1. In a method for improving properties for absorptive devices, the
improvement comprising: treating pulp with a cold caustic solution
to produce a cold caustic extracted pulp, wet laying said cold
caustic extracted pulp to obtain a wet-laid cold caustic extracted
pulp sheet; forming a dry pulp sheet suitable for incorporation in
an absorption intensive device from said wet-laid cold caustic
extracted pulp sheet; and cutting said dry pulp sheet into a shape
suitable for incorporation into said absorption intensive
device.
2. A process for improving the properties of absorption intensive
pulp material comprising: treating a pulp with a cold caustic
solution; wet laying said pulp on a wire screen to form a pulp
sheet; recovering said pulp sheet in a dry pulp form; and
incorporating said dry pulp form in an absorption intensive
device.
3. In a process for improving absorption intensive devices, the
improvement comprises: forming a wet-laid sheet of a cold caustic
extracted pulp; recovering a dried sheet from said wet-laid sheet;
and incorporating said dried sheet in an absorption intensive
device.
4. The method of claim 1, wherein said pulp is kraft pulp.
5. The method of claim 1, wherein said pulp is sulfite pulp.
6. The process of claim 2, wherein said pulp is kraft pulp.
7. The process of claim 2, wherein said pulp is sulfite pulp.
8. The method of claim 3, wherein said pulp is kraft pulp.
9. The process of claim 3, wherein said pulp is sulfite pulp.
10. An absorptive device prepared by the method of claim 1.
11. An absorption intensive pulp material prepared by the method of
claim 2.
12. An absorption intensive device prepared by the method of claim
3.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to absorbent pulps; more specifically
this invention relates to wet-laid pulp sheets which are
convertible to an end product without the added steps of
disintegrating a pulp sheet to make a fluff pulp and then
air-laying the pulp to make a sheet that is then cut up into
appropriate sizes to obtain the desired product. Still further,
this invention relates to the method of preparing a wet laid pulp
sheet from cold caustic extracted pulp.
[0003] 2. Description of the Related Art
[0004] In the production of absorbent devices such as baby diapers,
incontinence and catamenial devices and wound dressings, (i.e.,
absorption intensive devices), conventionally these products are
made by first making a pulp sheet of a dense, board-like nature.
Typically, these sheets are made by wet-laying the pulp and with
the aid of vacuum suction, and drying, making a rolled up bale of
pulp. Such rolled-up bales of pulp are then sent to the customer
who disintegrates the stiff, board-like sheet with a special device
to make a "fluff" pulp.
[0005] To reduce the power required for the disintegration, (i.e.,
fluffing) manufacturers of pulp will sometimes include additives.
These additives do, however, affect the cost and pulp properties as
used in the ultimate product.
[0006] After the disintegration, the fluff pulp is then air-laid
either directly on an appropriately sized wire screen; or, more
typically, the pulp is air-laid on a tissue sheet on a wire and
then an air-laid sheet is formed. Subsequently, the air-laid sheet
is cut up into the desired product shape such as a baby diaper and
like. As it is evident from the above description, not only are a
number of additional steps required to form the air-laid sheet, but
considerable capital investment is needed to reconstitute, in the
necessary form, and then to cut up such sheet.
[0007] Hence, it has been a desideratum to form immediately, i.e.,
wet-lay such sheet on a paper machine. However, the inherent
properties of pulp have made it unacceptable, if not impossible to
form an acceptable product of sufficient caliper (and other
properties) for the desired density or of sufficient lightness for
the caliper obtained. To obtain the desired absorption, insult (or
re-wetting), and liquid retention properties, softness, pad
integrity, etc., a number of additives are employed directly during
the pulp making stage, or more typically the product is made of
layers of pulp of different properties such as a core layer
including super absorbent polymer (SAP) and an acquisition layer
which has the desirable properties for acquisition and
re-wetting.
[0008] To eliminate the multiple steps in product formation, a
number of approaches have been proposed and implemented. For
example, machines have been designed to form "pads" or other
devices from pulp products in a female mold or cavity. Such
machines are typically large diameter devices of a number of
cavities around the circumference of a large drum or a belt. Such
operations are very capital intensive, and somewhat cumbersome and
slower than typical pulp forming machines employing wire screen
technology.
BRIEF DESCRIPTION OF THE INVENTION
[0009] It has now been found that by employing a properly prepared
pulp of characteristics which are desirable in the ultimate
consumer product, a wet-laid sheet may be formed which not only has
desirable properties but also may be rolled up, sent to the
converter and then immediately cut up without the costly and
capital intensive re-manufacture of a fluff pulp and an air-laid
sheet. Such wet-laid sheets are now made possible by the novel
combination of properties derived from the pulp disclosed in U.S.
application Ser. No. 08/370,571, filed Jan. 18, 1995 for COLD
CAUSTIC EXTRACTION OF PULPS FOR ABSORBENT PRODUCTS, METHOD OF THEIR
PREPARATION, AND PRODUCTS IMPROVED THEREBY by Phyllis Leithem et
al. The disclosure of the above application is incorporated by
reference herein. Processing of such sheet, either entirely made of
the pulp disclosed in the above application or by combining such
pulp in a wet-laid state with other pulps in appropriate
proportions to obtain the desired end uses eliminates a number of
steps and makes absorbent pulps of the cold caustic extracted type
more competitive with other types of pulp.
[0010] Not only are kraft pulps useful, but also sulfite pulps.
Sheets of appropriate caliper (bulk) and density are obtainable by
appropriate combinations of pulps of different characteristics, in
wet laid sheets which heretofore was not possible. Such added
benefits are to be considered especially because the disintegration
and air-laying steps have been entirely eliminated.
DETAILED DESCRIPTION OF THE INVENTION EXAMPLES AND EMBODIMENTS
THEREOF
EXAMPLE I
Kraft Pulp
[0011] To demonstrate that cold alkali extracted pulps would be
soft enough and absorbent enough to be used in the form of a wet
laid pulp sheet (i.e., no pressure applied to the formed fibrous
sheet to decrease moisture content) directly in an absorbent
product, eliminating the fluffing step entirely, a bleached
Southern pine conventional kraft pulp was cold caustic extracted
(CCE) with 15 and 18% NaOH, in accordance with the disclosure in
Ser. No. 08/370,571 and then wet laid to form sheets at 500 and
1000 g/m.sup.2 basis weight (BW). Some of the sheets were air-dried
and others were dried under heated conditions in a tunnel dryer
(47.degree. C.). Normal, 650 g/m.sup.2 standard BW sheets that were
pressed at 850 psi prior to drying were also prepared for
comparative purposes. Caliper and density measurements were made,
and these results are summarized in Tables I-1,2,3.
1TABLE I-1 Cold Caustic Extraction Conditions Condition Sample A-1
Sample B-1 Alkali used NaOH NaOH Solution strength, % 15 18
Temperature, .degree. C. 25 25 Time, H:M 0:10 0:10 Consistency, %
3.0 3.0 in 100 ml. of water
[0012]
2TABLE I-2 Caliper and Density of Pulp Sheets Prepared from A-1
Sample No: C-1 D-1 E-1 F-1 Standard, Wet Laid Wet Laid Wet Laid,
650 g/m.sup.2-BW, 1000 g/m.sup.2- 1000 g/m.sup.2- 500 g/m.sup.2-
Tunnel BW, Tunnel BW, Air BW, Tunnel Dried Dried Dried Dried
Caliper, 1.9 14.8 14.5 7.4 mm: Density, 0.34 0.07 0.07 0.07
g/cm.sup.2:
[0013]
3TABLE I-3 Caliper and Density of Pulp Sheets Prepared from B-1
Sample No. G-1 H-1 I-1 J-1 K-1 Standard, Wet Laid, Wet Laid, Wet
Laid, Wet 650 g/m.sup.2-BW 1000 g/m.sup.2-BW 1000 g/m.sup.2-BW 500
g/m.sup.2-BW Laid, Tunnel Tunnel Air Tunnel 500 g/m.sup.2 Air Dried
Dried Dried Dried Dried Caliper, 1.4 14.2 14.3 6.9 6.8 mm: Density,
0.46 0.07 0.07 0.07 0.07 g/cm.sup.2:
[0014] It is noted that density was not affected by the type of
drying or by changes in the basis weight. It appears that the
density is primarily a function of the pressing. The density of the
wet-laid sheets is about two-thirds that of the new "ultrathin"
diaper fluff cores now produced by Kimberly Clark and about
one-half that of typical diaper fluff core test pads (at equivalent
basis weights). The type of drying did not affect the caliper or
density of the sheet.
[0015] The various sheets prepared (C-1 to K-1) from the cold
caustic extracted pulps (A-1 and B-1) were evaluated "as-is" (by
cutting them up into appropriate sizes) along with normal fluff
Rayfloc-J.RTM. (a commercial fluff grade bleached kraft south pine
pulp produced at Jesup, Ga. by Rayonier Inc.) in a variety of
absorption tests. A number of comparisons were also made with three
types of a product made in a conventional manner, improved by one
layer and also by chemical cross-linking and layering of
cross-linked material with an acquisition layer and including a
material with a superabsorbent polymer core. The various tests
carried out and their results are presented and discussed
below.
Evaluation and Results
[0016] Pad Integrity is a measure of the strength of an absorbent
core. The pad integrity value is measured as the maximum force
required to push a 13/4" piston through the pad. Normal pad
integrity fluff pads have a basis weight of 500 g/m.sup.2 and a
density near 0.05 g/cm". Samples F-1, J-1 and K-1 had a basis
weight comparable to routine Rayfloc-J fluff sheet previously
identified above. The novel samples showed an increase in pad
integrity of approximately 40%. All the novel samples had higher
pad integrity values than routinely measured for Rayfloc-J.RTM.
fluff. Pad integrity test results are listed in Table I-4.
[0017] GATS (Gravimetric Absorbency Testing System) testing
measures the absorbency characteristics of an absorbent core. The
GATS test was performed with M/K Mark II GATS test equipment. The
test measures the quantity of deionized water absorbed into the
test sample through a 2 mm diameter hole. The test is controlled so
that there is no pressure head on the liquid. When the pad is
saturated, it is adjusted so that there is a one inch height
differential between the test piece (higher) and the liquid
reservoir (lower). This allows loosely retained liquid to drain
back into the test reservoir. The retention value is the amount of
liquid absorbed after draining is completed. The dry pad height is
measured as absorption begins and the wet pad height after draining
is completed.
[0018] GATS test results are shown in Tables I-5 and I-6. Each
sample was cut to a square weighing 1 gram (fluff samples are
prepared in a 2 inch diameter cylinder and weigh 1 gram). The
steady state absorption rates of the unpressed wet-laid sheets were
greater than what was observed for fluffed Rayfloc-J.RTM.. All the
wet-laid sheets reached their absorption capacity in about 20
seconds. This is approximately twice as fast as a conventionally
made fluffed pad. The retention for the unpressed sheets (all
samples except C-1 and G-1) was approximately 40% of that of a
fluffed pad. The pressed sheets (samples C-1 and G-1) had even
lower liquid retention. The GATS test also measures the change in
pad height as liquid is being absorbed (Table I-6). The novel
unpressed sheets maintained approximately 70% of their height,
compared to about 45% for conventional fluff pads. The pressed
sheets swell with absorption and increase about 130% in
caliper.
[0019] The acquisition layer test was done with the unfluffed wet
laid pulp sheets. This test is also done on absorbent products to
evaluate their performance. This test simulates the performance of
the sheet as an absorbent core. The sample is cut to 7 cm.times.17
cm and placed on a stack of 7 blotter sheets. For this example, the
blotter sheets would simulate a layer of a superabsorbent polymer
(SAP) under the pad. A piece of non-woven cover stock is placed on
top of the sample. A 50 ml "insult" of synthetic urine is
introduced to the pad via 2" diameter tube centered over the
sample. The time for the synthetic urine to completely penetrate
the cover stock is recorded. A stack of five blotter sheets is
placed on the sample 90 seconds after the synthetic urine is
absorbed. A weight applying 1 psi of pressure to the sample is
placed on the blotter stock. After 120 seconds the weight and
blotter sheets are removed. The amount of synthetic urine absorbed
by the blotter sheets is the rewet value.
[0020] Product test results for three designs of Proctor &
Gamble diapers are included with the test results in Table I-7. The
Pampers Uni.RTM. (made in Thailand) is a simple one-piece fluff
core with 13% superabsorbent polymer (SAP). The Pampers.RTM. (made
in Japan) is a two-piece fluff core with 21% SAP in the lower pad.
The Pampers UltraThin.RTM. (made in the United States) has an upper
layer of curly acquisition fiber and a lower layer of fluff and 35%
superabsorbent. Lower absorption times are preferable as are lower
rewet times. The unpressed cores (all samples except C-1 and G-1)
had absorption times comparable to the Japanese Pampers.RTM. but
worse than the Pampers Ultrathin.RTM.. The rewet of the lower basis
weight (samples F-1, J-1 and K-1) wet laid pulp sheets was
equivalent to the Japanese Pampers.RTM. and the Pampers
Ultrathin.RTM.. All the unpressed cores outperformed the Pampers
Uni.RTM. diaper. The pressed pulp sheets (samples C-1 and G-1) had
very low absorption times.
4TABLE I-4 PAD INTEGRITY RESULTS Pad Basis Integrity Density Weight
Sample Number (N) (g/cm.sup.3) (g/cm.sup.3) Pressing C-1 31.8 0.34
650 850 psi D-1 22.6 0.07 1000 None E-1 20.1 0.07 1000 None F-1
11.1 0.07 500 None G-1 40.0 0.46 650 850 psi H-1 26.3 0.07 1000
None I-1 23.9 0.07 1000 None J-1 10.6 0.07 500 None K-1 10.9 0.07
500 None Rayfloc-J .RTM. 7.7 0.05 500 N/A
[0021]
5TABLE I-5 GATS ABSORBENCY TEST RESULTS Absorption Absorption
Liquid Rate Time Retention Sample No. (ml/sec) (sec) (g/g) C-1 0.19
21.4 4.44 D-1 0.63 22.8 9.27 E-1 0.66 21.7 9.77 F-1 0.55 20.1 9.69
G-1 0.14 20.0 3.52 H-1 0.79 16.4 8.48 I-1 0.67 17.6 8.07 J-1 0.71
20.6 9.23 K-1 0.56 21.3 8.85 Rayfloc-J .RTM. 0.40 45.2 14.4
[0022]
6TABLE I-6 GATS PAD HEIGHT TEST RESULTS Dry Pat Wet Pad Sample No.
(mm) (mm) Wet:Dry (%) C-1 2.09 2.72 130 D-1 10.96 7.46 68 E-1 11.36
7.36 67 F-1 6.20 4.68 75 G-1 1.79 2.36 132 H-1 10.68 7.44 70 I-1
10.70 7.46 70 J-1 6.11 4.65 76 K-1 5.83 4.40 75 Rayfloc-J .RTM.
14.87 6.67 45
[0023]
7TABLE I-7 ACQUISITION LAYER/PERFORMANCE TEST RESULTS Time(sec)
Rewet(g) SAMPLE 1st 2nd 3rd 1st 2nd 3rd C-1 27.4 103.0 153.2 4.16
4.45 11.30 D-1 6.4 25.6 37.8 9.08 16.60 18.68 E-1 0.8 32.8 93.8
8.48 16.48 17.26 F-1 3.2 41.3 69.4 2.52 8.98 21.43 G-1 42.1 128.2
178.0 3.36 8.39 8.32 H-1 1.2 12.4 24.0 7.31 15.00 16.56 I-1 0.9
28.6 37.8 6.96 18.91 13.72 J-1 3.7 40.2 83.6 2.14 7.15 20.22 K-1
3.4 34.4 74.1 8.12 6.84 21.50 Pampers Uni .RTM. 4.6 46.4 66.5 22.01
30.11 38.48 Pampers .RTM. (Japan) 8.5 46.6 63.1 8.79 13.43 21.29
Pampers 8.0 23.6 30.9 1.94 15.11 21.71 Ultrathin .RTM. (USA)
[0024] The overall absorbency results presented above are
outstanding as they indicate that the cold caustic extracted,
wet-laid, pulp sheet is an excellent candidate material for
absorbent cores. This material can outperform multi-layer, SAP
containing devices. This material exhibits excellent absorption and
pad integrity. Performance of the novel sheets is equivalent to
diapers without a special acquisition layer fiber. It does not
appear that the solution strength of the caustic used in the CCE
stage (15% or 18% studied here) or the type of drying (air or
tunnel dried) has much effect on the absorbent or strength
properties. Moreover, less wet pad collapse is observed in the
wet-laid pulp sheet compared to fluff pads.
EXAMPLE II
Sulfite Pulp
[0025] Two series of cold caustic extracted (CCE)
Ethenier-F-UHV.RTM. (Ultrahigh Viscosity Sulfite Southern Pine pulp
produced by Rayonier Inc.) wet laid pulp sheets were tested in a
manner similar to Example I for use as an absorbent core without
fluffing. The first series was treated with an 18% cold caustic
extraction (CCE) and the second was treated with a 15% CCE. Each
series contained samples at 650 g/m.sup.2 (basis weight) that were
conventionally pressed, and 1000 g/m.sup.2 and 500 g/m.sup.2 sheets
that were not pressed. Some of the unpressed sheets were air dried
and others were dried in a tunnel drier.
[0026] Table II-1 summarizes the properties of the wet laid sheets.
Density and caliper results are listed in Table II-2. The density
was not affected by the type of drying or by changes in the basis
weight. It appears that the density is primarily a function of the
pressing. These results are similar to those observed with
Porosanier-J-HP.RTM. (mercerized kraft Southern Pine pulp produced
by Rayonier Inc.).
Evaluation and Results
[0027] Pad integrity test results are listed in Table II-3. Pad
integrity is a measure of the strength of an absorbent core. Normal
pad integrity fluff pads have a basis weight of 500 g/m.sup.2 and a
density near 0.05 g/cm.sup.3. CCE samples at a basis weight
comparable to Rayfloc-J.RTM. fluff showed an increase in pad
integrity of approximately 6%. The CCE samples were slightly higher
in density than Rayfloc-J.RTM.. Pad integrity for the CCE wet laid
sheets appears to be proportional to the basis weight, as the
higher basis weight sheets were higher in pad integrity. Pressed
sheets had greater pad integrity values.
[0028] GATS (Gravimetric Absorbency Testing System) testing
measures the absorbency characteristics of an absorbent core. GATS
test results are shown in Tables II-4 and II-5. Each sample was cut
to a square weighing 1 gram (fluff samples are prepared in a 2-inch
diameter cylinder and weigh 1 gram). The steady state absorption
rates of the unpressed wet-laid sheets were greater than what was
observed for Porosanier-J-HP.RTM. and Rayfloc-J.RTM.. All the
wet-laid sheets reached their absorption capacity in about 20
seconds. This is approximately twice as fast as fluffed pads. The
retention for the unpressed sheets was approximately 60% of that of
fluffed pads. The pressed sheets had even lower liquid
retention.
[0029] The GATS test also measures the change in pad height as
liquid is being absorbed. The results are shown in Table II-5. The
unpressed sheets maintained approximately 70% of their height,
compared to about 45% for fluff pads. Because the unpressed sheets
have less wet collapse, their absorption rate is higher than
regular fluff pads. The pressed sheets swell with absorption and
increase in caliper about 170%.
[0030] The acquisition layer test was done with the unfluffed wet
laid pulp sheets. This test is also done on absorbent products to
evaluate their performance. This test stimulates the performance of
the sheet as an absorbent core. Product test results for three
designs of Proctor & Gamble diapers are included with the test
results in Table II-6. The Pampers Uni.RTM., Japanese Pampers.RTM.,
and Pampers UltraThin.RTM. were again used for comparison (as in
Example I).
[0031] Lower absorption times are better as are lower rewet times.
For an absorbent core, rewet is as important as fast liquid
absorption. The unpressed cores had absorption times comparable to
the Japanese Pampers.RTM. and the Pampers Ultrathin.RTM.. The rewet
of the lower basis weight wet laid pulp sheets were slightly worse
than the Japanese Pampers.RTM. and the Pampers Ultrathin.RTM.,
however, the thinner pads transferred some urine to the under layer
of blotter stock, which may account for the lower rewets observed
in these sheets. All the unpressed cores outperformed the Pampers
Uni.RTM. diaper.
[0032] Unpressed CCE Ethenier-F-HV.RTM. (a sulfite chemical
Southern Pine pulp produced by Rayonier Inc.) pulpsheets according
to the invention exhibit excellent absorption and pad integrity.
Their performance is equivalent to diapers without a special
acquisition layer fiber. There also appears to be less wet pad
collapse in the wet-laid pulp sheets compared to fluff pads.
8TABLE II-1 WET LAID PULPSHEET PROPERTIES CAUSTIC BASIS SAMPLE
TREATMENT WEIGHT DRYING NO. (%) (g/m.sup.2) PRESSING TYPE A-2* 18
650 850 psi Tunnel B-2 18 1000 None Tunnel C-2 18 1000 None Air D-2
18 500 None Tunnel E-2 18 500 None Air F-2* 15 650 850 psi Tunnel
G-2 15 1000 None Air H-2 15 1000 None Tunnel I-2 15 500 None Air
J-2 15 500 None Tunnel *--Standard sheet.
[0033]
9TABLE II-2 CALIPER AND DENSITY OF PULP SHEETS BASIS WEIGHT CALIPER
DENSITY SAMPLE NO. (g/m.sup.2) (mm) (g/cm.sup.3) A-2* 650 2.3 0.28
B-2 1000 13.3 0.08 C-2 1000 14.0 0.07 D-2 500 7.4 0.07 E-2 500 7.0
0.07 F-2* 650 2.4 0.27 G-2 1000 13.6 0.07 H-2 1000 15.1 0.07 I-2
500 8.4 0.06 J-2 500 7.6 0.07 Test Fluff Pad Typical 500 14.2 0.03
Properties to 0.04 Pampers Uni .RTM.-13% SAP 490 10.7 0.06 Pampers
.RTM. (Japan)-21% SAP 840 9.3 0.07 Pampers UltraThin .RTM. (USA)**-
670 8.1 0.10 35% SAP *--Standard sheet. **--Includes curly fiber
acquisition layer.
[0034]
10TABLE II-3 PAD INTEGRITY RESULTS PAD BASIS INTEGRITY DENSITY
WEIGHT SAMPLE NO. (N) (g/cm.sup.3) (g/m.sup.2) PRESSING A-2* 37.9
0.28 650 850 psi B-2 19.5 0.08 1000 None C-2 24.1 0.07 1000 None
D-2 7.9 0.07 500 None E-2 9.0 0.07 500 None F-2* 27.1 0.27 650 850
psi G-2 20.8 0.07 1000 None H-2 21.0 0.07 1000 None I-2 8.1 0.06
500 None J-2 7.5 0.07 500 None Rayfloc-J .RTM. 7.7 0.05 500 N/A
*--Standard sheet.
[0035]
11TABLE II-4 GATS ABSORBENCY TEST RESULTS ABSORPTION RATE
ABSORPTION LIQUID SAMPLE NO. (mL/sec) TIME (sec) RETENTION (g/g)
A-2* 0.20 17.9 3.51 B-2 0.57 21.2 8.41 C-2 0.61 19.0 7.89 D-2 0.72
19.8 9.86 E-2 0.60 22.9 10.0 F-2* 0.09 20.3 2.98 G-2 0.60 18.5 8.74
H-2 0.53 22.7 8.93 I-2 0.58 25.1 10.4 J-2 0.55 23.9 10.1 Rayfloc-J
.RTM. 0.40 45.4 14.4 *--Standard sheet.
[0036]
12TABLE II-5 GATS PAD HEIGHT TEST RESULTS DRY PAD WET PAD SAMPLE
NO. (mm) (mm) WET:DRY (%) A-2* 1.30 2.08 166 B-2 9.93 6.98 70 C-2
11.38 7.75 68 D-2 5.85 4.45 76 E-2 6.00 4.55 76 F-2* 0.86 1.71 189
G-2 10.11 7.19 71 H-2 8.10 5.86 72 I-2 4.70 3.45 73 J-2 5.18 4.00
76 Rayfloc-J .RTM. 14.87 6.67 45 *--Standard sheet.
[0037]
13TABLE II-6 ACQUISITION LAYER/PERFORMANCE TEST RESULTS TIME(sec)
REWET(g) SAMPLE NO. 1st 2nd 3rd 1st 2nd 3rd A-2* 20.3 78.8 125.4
4.31 5.93 15.08 B-2 0.4 7.4 21.4 8.50 13.11 19.91 C-2 0.5 7.1 35.4
9.11 14.91 16.29 D-2 1.7 26.2 44.5 3.86 13.32 19.84 E-2 1.8 27.7
49.4 5.02 9.11 21.53 F-2* 21.6 87.4 132.9 5.03 5.44 13.53 G-2 0.6
11.5 18.5 8.04 15.30 22.07 H-2 0.4 9.7 17.9 10.77 16.27 19.00 I-2
1.3 14.7 25.1 7.64 12.49 13.48 J-2 1.5 19.5 37.2 8.47 12.71 24.07
Pampers Uni .RTM. 4.6 46.4 66.5 22.01 30.11 38.48 Pampers .RTM. 8.5
46.6 63.1 3.79 13.43 21.29 (Japan) Pampers 8.0 23.6 30.9 1.94 15.11
21.71 UltraThin .RTM. (USA)** *Standard sheet. **Includes curly
fiber acquisition layer.
EXAMPLE III
[0038] A composite of CCE pulp and conventional fluff pulp is
formed by mixing the pulps in a 50/50 CCE to conventional pulp
ratio. The resultant composite would exhibit properties approximate
to the average of the properties for the individual CCE and
conventional pulps. For example, the values for absorption rate,
absorption time and liquid retention of the composite pulp would be
expected to be between the corresponding values for the individual
pulp materials. Intermediate results would be achieved with a
mixture of CCE pulp with amount of CCE pulp being as low as 10% by
weight. Such composites would be useful for designing materials
with specific properties for use in adsorptive devices.
[0039] From this it follows that property-wise, the method as
described herein and the products obtained accordingly have
substantial advantages over the conventionally produced products,
i.e., products obtained by disintegration (fluffing) and air-laying
the fluffed pulp. The strength of the material, measured in terms
of pad integrity, is at least equal to and often exceeds that of
conventionally produced products of the same basis weight. As the
pad integrity is often improved, the present product is stronger
despite its softness.
[0040] Based on the extensive data concerning absorption rates and
absorption capacity, the disclosed method produces pulps for the
disclosed devices of much improved properties with absorption rates
that have been improved from about 37% to 98% based on comparable
conventionally produced product.
[0041] Although the above discussion has been with respect to pulp
made of cold caustic extracted kraft or sulfite pulps, the
equivalent property definition provides a ready vehicle for
evaluating properties for absorption intensive applications. By
combining lesser quality pulps with the novel pulps to achieve
results achieved by the prior art more expensive pulps, one is
provided with an economically viable alternative to fashion
outstanding products for intense absorption purposes.
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