U.S. patent application number 10/999660 was filed with the patent office on 2005-04-07 for polymeric binders having specific peel and cure properties and useful in making creped webs.
Invention is credited to Goldstein, Joel Erwin, Pangrazi, Ronald Joseph.
Application Number | 20050074624 10/999660 |
Document ID | / |
Family ID | 21824122 |
Filed Date | 2005-04-07 |
United States Patent
Application |
20050074624 |
Kind Code |
A1 |
Goldstein, Joel Erwin ; et
al. |
April 7, 2005 |
Polymeric binders having specific peel and cure properties and
useful in making creped webs
Abstract
This invention is directed to APE-free polymer binders formed by
emulsion polymerization and having specific peel and cure
properties. The APE-free polymeric binders have a peel value, when
adhered to a heated metal surface, of 35% to 200% of the peel value
shown by a standard APE-based polymer binder control (i.e.,
AIRFLEX.RTM. 105 vinyl acetate-ethylene polymer emulsion) and
exhibit a cure profile such that at least 55% cure is achieved
within 30 seconds at a temperature required for cure. Wet tensile
strength is used as a measure of cure. The peel value is determined
by a modified release and adhesion test. Binders having the peel
and cure properties described herein can be considered for use in
crepe processes, especially DRC processes.
Inventors: |
Goldstein, Joel Erwin;
(Allentown, PA) ; Pangrazi, Ronald Joseph;
(Fleetwood, PA) |
Correspondence
Address: |
AIR PRODUCTS AND CHEMICALS, INC.
PATENT DEPARTMENT
7201 HAMILTON BOULEVARD
ALLENTOWN
PA
181951501
|
Family ID: |
21824122 |
Appl. No.: |
10/999660 |
Filed: |
November 30, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10999660 |
Nov 30, 2004 |
|
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10025114 |
Dec 19, 2001 |
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6824635 |
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Current U.S.
Class: |
428/522 |
Current CPC
Class: |
Y10T 428/24446 20150115;
Y10T 428/31935 20150401; C08F 2/24 20130101 |
Class at
Publication: |
428/522 |
International
Class: |
B32B 027/30 |
Claims
What is claimed is:
1. An alkylphenol ethoxylate-free polymer binder, said polymer
binder formed by emulsion polymerization and having a peel value of
35% to 200% of a standard alkylphenol ethoxylate-based vinyl
acetate-ethylene polymer emulsion control and a cure profile in
which 55% cure is achieved within 30 seconds of being exposed to a
temperature required for cure, said polymer binder effective as a
binder in a crepe process; wherein the peel value is measured
according to the following procedure: (a) attaching a
2-inch.times.6-inch.times.{fraction (1/32)}-inch stainless steel
plate to a movable heated (350.degree. F.; 177.degree. C.) inclined
(45.degree.) metal platform; (b) allowing the stainless steel plate
to equilibrate to the temperature of the platform (2 minutes; (c)
applying approximately 0.42 g of the alkylphenol ethoxylate-free
polymer binder to a 11/2-inch.times.6-inch piece of bleached,
mercerized cotton poplin; (d) attaching the jaws of a Testing
Machine, Inc. gram tensile measuring apparatus to one of the long
ends of the cotton poplin; (e) pressing the coated side of the
coated cotton poplin onto the heated stainless steel plate with a
3-pound lab roller by rolling the lab roller back and forth over
the substrate for 10 seconds; (f) after 30 seconds, moving the
stainless steel plate away from the tensile measuring device (to
which the cotton poplin is attached) at a rate of 12 inches/minute
(30.48 cm/minute); (g) recording the amount of force needed to
remove the cotton from the stainless steel plate; and (h) comparing
the force in (g) to the force needed to remove cotton poplin using
an AIRFLEX 105 VAE emulsion control.
2. The polymer binder of claim 1 wherein said crepe process is a
double recrepe process.
3. The polymer binder of claim 2 wherein the peel value is 50 to
125% of control binder.
4. An alkylphenol ethoxylate-free polymer binder, said polymer
binder formed by emulsion polymerization and having a peel value of
35% to 200% of a standard alkylphenol ethoxylate-based vinyl
acetate-ethylene polymer emulsion control and a cure profile in
which 55% cure is achieved within 30 seconds of being exposed to a
temperature required for cure, said polymer binder effective as a
binder in a double recrepe process, wherein the peel value is
measured according to the following procedure: (a) attaching a
2-inch.times.6-inch.times.{fraction (1/32)}-inch stainless steel
plate to a movable heated (350.degree. F.; 177.degree. C.) inclined
(45.degree.) metal platform; (b) allowing the stainless steel plate
to equilibrate to the temperature of the platform (2 minutes; (c)
applying approximately 0.42 g of the alkylphenol ethoxylate-free
polymer binder to a 11/2-inch.times.6-inch piece of bleached,
mercerized cotton poplin; (d) attaching the jaws of a Testing
Machine, Inc. gram tensile measuring apparatus to one of the long
ends of the cotton poplin; (e) pressing the coated side of the
coated cotton poplin onto the heated stainless steel plate with a
3-pound lab roller by rolling the lab roller back and forth over
the substrate for 10 seconds; (f) after 30 seconds, moving the
stainless steel plate away from the tensile measuring device (to
which the cotton poplin is attached) at a rate of 12 inches/minute
(30.48 cm/minute); (g) recording the amount of force needed to
remove the cotton from the stainless steel plate; and (h) comparing
the force in (g) to the force needed to remove cotton poplin using
an AIRFLEX 105 VAE emulsion control.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 10/025,114, filed on Dec. 19, 2001.
BACKGROUND OF THE INVENTION
[0002] Crepe processes, especially double recrepe (DRC) processes,
have been used to produce paper products, such as paper towels and
wipes, with specific properties. The DRC process involves creping a
base sheet or nonwoven web on a drum, printing a polymeric binder
on one side of the sheet, flash drying the binder, creping the base
sheet on a drum again, printing a polymeric binder on the other
side of the base sheet, flash drying the binder, and then creping
the base sheet a third time. The base sheet is printed while
traveling through gravure nip rolls. Various crepe processes and
binding materials used in the processes are known. Examples of such
processes are disclosed in U.S. Pat. No. 3,879,257, U.S. Pat. No.
3,903,342, U.S. Pat. No. 4,057,669, U.S. Pat. No. 5,674,590, and
U.S. Pat. No. 5,776,306.
[0003] In order for the base sheet or web to adhere adequately to
the creping drum, polymeric binders used in creping processes are
typically emulsion polymers containing surfactants that are based
on alkylphenol ethoxylates (APEs). Known emulsion polymeric
binders, that are free of alkylphenol ethoxylates, have not been
effective in creping processes, especially DRC processes, because
they do not provide the necessary adhesion to creping drums,
produce an unacceptable amount of foam, are too low in viscosity,
decompose at elevated temperatures, causing an unacceptable odor,
and/or are subject to felt filling.
[0004] Appropriate binders for making paper products using a crepe
process should be free of APE-based surfactants, adhere to a
creping drum, provide a high degree of softness and absorbency to
the finished product, and not felt-fill.
[0005] Heretofore, specific measurable properties for predicting
the effectiveness of binders for a crepe process have not been
reported.
BRIEF SUMMARY OF THE INVENTION
[0006] This invention is directed to APE-free polymer binders
formed by emulsion polymerization techniques and having a specific
peel value and a specific cure profile. Binders having the peel
value and cure profile described herein can be considered for use
in crepe processes, especially DRC processes. According to this
invention, the APE-free polymeric binders have a peel value, when
adhered to a heated metal surface, of 35% to 200% of the peel value
shown by a standard APE-based polymer binder control (i.e.,
AIRFLEX.RTM. 105 vinyl acetate-ethylene (VAE) polymer emulsion) and
exhibit a cure profile such that at least 55% cure is achieved
within 30 seconds at a temperature required for cure. Wet tensile
strength is used to determine the cure profile. The peel value is
determined by a modified release and adhesion test.
[0007] Binders having the properties described above are excellent
candidates for use in crepe, especially DRC, processes. When used
in making paper products, they should adhere to the creping drum
providing a high degree of softness and absorbency to the finished
paper product and not felt-fill; thus reducing production breaks,
while ensuring that the desired finished product is
manufactured.
DETAILED DESCRIPTION OF THE INVENTION
[0008] Any APE-free polymer prepared according to well known
emulsion polymerization techniques and manifesting the requisite
cure profile and peel value is suitable in this invention.
[0009] APE-free polymer emulsions can be formed by polymerizing one
or more ethylenically unsaturated monomers and optionally one or
more crosslinking monomers, under emulsion polymerization
conditions, in the presence of a combination of a specific anionic
surfactant and a specific nonionic surfactant, wherein said anionic
surfactant is a sodium laureth sulfate having 1 to 12 moles of
ethylene oxide, said nonionic surfactant is a secondary alcohol
ethoxylate containing 7 to 30 moles of ethylene oxide or an
ethoxylated branched primary alcohol containing 3 to 30 moles of
ethylene oxide, said primary or secondary alcohol containing 7 to
18 carbons
[0010] Ethylenically unsaturated monomers that can be used in the
preparation of the polymer emulsions of this invention include, but
are not limited to, vinyl esters, such as vinyl acetate, ethylene,
styrene, butadiene, C.sub.1-8 alkyl esters of acrylic and
methacrylic acid, such as methyl (meth)acrylate, ethyl
(meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate,
2-ethylhexyl (meth)acrylate, diacrylates, unsaturated carboxylic
acid, such as acrylic, methacrylic, crotonic, itaconic, and maleic
acid, acrylonitrile, and vinyl esters of C.sub.2-10 alcohols.
[0011] The polymer can contain up to 10% of one or more
crosslinking monomers. Examples of crosslinking monomers are
N-(C.sub.1-4) alkylol (meth)acrylamide, such as N-methylol
acrylamide, i-butoxy methylacrylamide, acrylamidoglycolic acid,
acrylamidobutyraldehyde, and the dialkyl acetal of
acrylamidobutyraldehyde in which the alkyl can have 1 to 4 carbons.
Any of the crosslinking monomers can be used alone, together, or in
combination with acrylamide.
[0012] Polymer emulsions comprising 50 to 90 wt % (preferably 70 to
85 wt %) vinyl acetate, 5 to 44 wt % (preferably 10 to 30 wt %)
ethylene, and 1 to 10 wt % (preferably 3 to 8 wt %) one or more
crosslinking monomer, based on the total weight of monomers, can be
formed using the surfactant package described herein.
[0013] The emulsion polymerization may be conducted in a stage or
sequential manner and can be initiated by thermal initiators or by
a redox system. A thermal initiator is typically used at
temperatures at or above about 70.degree. C. and redox systems are
preferred at temperatures below about 70.degree. C. The amount of
thermal initiator used in the process is 0.1 to 3 wt %, preferably
more than about 0.5 wt %, based on total monomers. Thermal
initiators are well known in the emulsion polymer art and include,
for example, ammonium persulfate, sodium persulfate, and the like.
The amount of oxidizing and reducing agent in the redox system is
about 0.1 to 3 wt %. Any suitable redox system known in the art can
be used; for example, the reducing agent can be a bisulfite, a
sulfoxylate, ascorbic acid, erythorbic acid, and the like. Examples
of oxidizing agent are hydrogen peroxide, organic peroxides, such
as t-butyl peroxide or t-butyl hydroperoxide, persulfates, and the
like.
[0014] Effective emulsion polymerization reaction temperatures
range from about 50 and 100.degree. C.; preferably, 75 to
90.degree. C., depending on whether the initiator is a thermal or
redox system.
[0015] The specific combination of anionic and nonionic surfactants
for the emulsion polymerization process has been shown to produce
crosslinking polymer emulsions that are effective as binders in a
creping process, especially a DRC process. The anionic surfactant
is a sodium laureth sulfate having 1 to 12, preferably 2 to 5,
moles of ethylene oxide. An example of an appropriate anionic
surfactant is Disponil FES 32 IS (sodium laureth sulfate containing
4 moles of ethylene oxide), supplied by Cognis as a 30% aqueous
solution. The nonionic surfactant is a secondary alcohol
ethoxylate, such as 2-pentadecanol ethoxylate, containing 7 to 30
moles, preferably 12 to 20 moles, of ethylene oxide or an
ethoxylated branched primary alcohol, such as tridecanol
ethoxylate, containing 3 to 30 moles, preferably 9 to 20 moles, of
ethylene oxide. The primary or secondary alcohol can contain 7 to
18, preferably 9 to 14 carbons. An example of an appropriate
nonionic surfactant is Tergitol 15-S-20 (a secondary alcohol
ethoxylate containing 20 moles of ethylene oxide), supplied by Dow
as an 80% aqueous solution.
[0016] The amount of active surfactant, based on total polymer, can
be 1 to 5 wt % (preferably 1.5 to 2 wt %) for the anionic
surfactant and 0.25 to 5 wt % (preferably 0.5 to 1.5%) for the
nonionic surfactant. The weight ratio of anionic to nonionic
surfactant can range from 4:1 to 1.5:1. A weight ratio of 65:35
(anionic:nonionic surfactant) has been found to give a latex that
provides appropriate adhesion to creping drums, has a moderate
viscosity with little foam generation, results in less off-gassing
than APE-based latexes, and has an accelerated sedimentation of no
greater than 1%.
[0017] The peel value of prospective polymeric binders for use in
crepe processes, especially DRC processes can be measured using the
following adhesion and release procedure:
[0018] A 2-inch.times.6-inch.times.{fraction (1/32)}-inch stainless
steel plate was attached to a movable heated (350.degree. F.;
177.degree. C.) inclined (45.degree.) metal platform and allowed to
equilibrate to the temperature of the platform (2 minutes.)
Approximately 0.42 g of the polymer emulsion is applied to a
11/2-inch.times.6-inch piece of bleached, mercerized cotton poplin.
The jaws of a Testing Machine, Inc. gram tensile measuring
apparatus are attached to one of the long ends of the cotton
poplin. The coated side of the coated cotton poplin is then pressed
onto the heated stainless steel plate with a 3-pound lab roller by
rolling the lab roller back and forth over the substrate for 10
seconds. After 30 seconds, the stainless steel plate is moved away
from the tensile measuring device (to which the substrate is
attached) at a rate of 12 inches/minute (30.48 cm/minute). The
amount of force needed to remove the cotton from the stainless
steel plate is recorded and compared to AIRFLEX 105 VAE emulsion
control.
[0019] The AIRFLEX 105 polymer emulsion can be prepared in small
batches as follows: Initially charge a one-gallon, stirred,
stainless steel reaction vessel with 883.5 g of deionized water,
305 g of Polystep OP-3S surfactant mixture (20% active) of
octylphenol ethoxylate (3 moles) and sodium sulfate salt of
octylphenol ethoxylate (3 moles), supplied by Stefan, 0.91 g of
sodium citrate, 3.5 g of 50% aqueous citric acid, 2.3 g of 5%
aqueous ferric ammonium sulfate, and 312.0 g of vinyl acetate.
While stirring, introduce 240.0 g of ethylene below the surface of
the liquid in the reaction vessel in order that the interpolymers
have a vinyl acetate:ethylene ratio of about 80:20. Heat the
reaction vessel to 50.degree. C. Upon equilibration, add the
following four aqueous solutions intermittently to the reaction
vessel over the course of the reaction (on a delay basis); 15%
sodium formaldehyde sulfoxylate (SFS), 3.0% t-butylhydroperoxide
(t-bhp), 1246.0 g of vinyl acetate and 324.0 g of a 30% aqueous
solution of N-methylol acrylamide (NMA). After three hours,
terminate the vinyl acetate delay. Complete the NMA delay after
four hours, and continue the other two delays for another 30
minutes. Terminate the reaction by cooling.
[0020] The cure profile is determined by measuring wet tensile
strength. The following procedure can be followed:
[0021] A 2-inch.times.6-inch unbonded DRC basesheet at about 65 gsm
basis is coated with a binder and the binder is cured at
320.degree. F. (160.degree. C.) for 30 seconds and for 180 seconds.
The cup of a Finch Wet Strength apparatus from Thwing-Albert,
Philadelphia, is filled with an aqueous solution containing
approximately 1% active Aerosol OT-75 wetting surfactant (from
Cytex Industries). The cured coated basesheet is then placed around
the bar on the Finch cup attachment and the two long ends of the
sample are clamped to the top jaw. The Finch cup holder is pulled
over the middle of the coated basesheet and the coated basesheet is
allowed to soak in the aqueous surfactant solution for 15 seconds.
The coated basesheet is then pulled away from the bar until the
basesheet breaks. The force required to break the basesheet is
recorded. If the wet tensile strength of the bound basesheet cured
for 30 seconds is at least 75% the wet strength of the 180-second
cured bound basesheet, the binder will not felt-fill due to
insufficient cure. For purposes of evaluating binders for use in a
crepe process, at least 55%, of the ultimate wet tensile strength
is achieved within 30 seconds at the cure temperature.
[0022] Polymer binders that show a peel value of 35% to 200%
(preferably 50% to 125%) of AIRFLEX 105 VAE emulsion control and a
cure profile in which at least 55% of the ultimate wet strength is
achieved in 30 seconds at the cure temperature, are considered
important candidates as binders for a crepe process, especially a
DRC process.
[0023] To be used in a crepe process, especially a DRC process, the
polymer emulsions identified by the peel and cure tests described
above, should have a viscosity of 5 to 80 cps at about 30% solids,
and should be capable of being thickened to 100 cps with a
thickener, such as a hydroxyethyl cellulose-based thickener.
Viscosity is measured using a Brookfield viscometer, Model LVT,
spindle #3 at 60 rpm. The emulsion polymers of this invention
should also be stable at temperatures up to about 550.degree. F.
(288.degree. C.). The polymer emulsions should produce a minimal
amount of foam when pumped and beaten during a DRC process.
[0024] Binders identified by this invention can be used in crepe
processes well known in the art. Examples of crepe processes are
described in the publications listed in the "Background of the
Invention" section of the specification. Nonwoven webs typically
used in a crepe process are wood pulp (alone or blended with
natural or synthetic fibers) processed by a dry (air-laid, carded,
rando) or wet-laid process.
[0025] The amount of binder applied to the web can vary over a wide
range; for example, about 5 to 40%; preferably 10 to 35% of the
finished product. When the products are wiper products, it is
desirable to keep the amount to a minimum.
[0026] The invention will be further clarified by a consideration
of the following examples, which are intended to be purely
exemplary of the use of the invention.
EXAMPLE
[0027] Emulsion polymerization of vinyl acetate, ethylene, and
N-methylol acrylamide was carried out in presence of various
surfactant systems in a one-gallon stirred, stainless steel
reaction vessel equipped with a jacket. In Run 1, reaction vessel
was charged initially with 883.5 g of deionized water, 126.75 g of
Disponil FES 32 IS, 25.625 g of Tergitol 15-S-20, 0.91 g of sodium
citrate, 3.5 g of 50% aqueous citric acid, 2.3 g of 5% aqueous
ferric ammonium sulfate and 312.0 g of vinyl acetate. While
stirring, 240.0 g of ethylene was introduced below the surface of
the liquid in the reaction vessel in order that the interpolymers
would have a vinyl acetate:ethylene ratio of about 80:20. The
reaction vessel was heated to 50.degree. C. Upon equilibration, the
following four aqueous solutions were intermittently added to the
reaction vessel over the course of the reaction (on a delay basis);
15% sodium formaldehyde sulfoxylate (SFS), 3.0%
t-butylhydroperoxide (t-bhp), 1246.0 g of vinyl acetate and 324.0 g
of a 30% aqueous solution of N-methylol acrylamide (NMA). After
three hours, the vinyl acetate delay was terminated. After four
hours the NMA delay was complete and the other two delays continued
for another 30 minutes. The reaction was terminated by cooling.
[0028] Using the same emulsion recipe as Run 1, several surfactant
packages were examined. The viscosity, emulsion stability,
accelerated sedimentation, peel (% of AIRFLEX 105 VAE emulsion
control), and 30-second wet tensile strength (% of ultimate wet
tensile strength) were measured.
[0029] Viscosity was measured using a Brookfield viscometer, Model
LVT, spindle #3 @ 60 rpm and 77.degree. F. (25.degree. C.), at
about 24 hours after preparation to allow for cooling and the
finishing of any residual-free monomer.
[0030] Emulsion stability was measured by measuring the viscosity
at 4 intervals: after forming the polymer emulsion; after 3 days in
a 120.degree. F. oven; after 1 week in a 120.degree. F. oven; and
after 2 weeks in a 120.degree. F. oven.
[0031] Accelerated sedimentation was measured by taking a sample of
product and diluting it in half with water, spinning it in a
centrifuge for five minutes at a predetermined setting, e.g., 2800
rpm.+-.100, and measuring the amount of precipitate forced to the
bottom of the tube. When a one-gallon reactor is used, an
accelerated sedimentation higher than 1% is considered
unsatisfactory. However in a plant-size operation, up to about 3%
is acceptable.
[0032] The peel value and the wet tensile strength of each of the
binders were determined as described above.
[0033] The results of the tests are presented in the table
below:
1TABLE Ratio of Peel 30-second Anionic Value wet tensile Anionic
Nonionic to % Viscosity, Accelerated (% (% of Run surfactant
surfactant Nonionic Solids cps Sedimentation, % control) ultimate)
1 Disponil Tergitol 1.86 52.9 660 1.0 100 79.4 FES 32 IS 15-S-20 2
B-330S Tergitol 1.86 53.2 532 4.0 47 70.0 15-S-20 3 Rhodapex
Tergitol 1.86 53.2 632 2.5 73 no data ES 15-S-20 4 FES 993 Tergitol
1.86 53.1 160 8.0 57 60.9 15-S-20 5 Steol 4N Tergitol 1.86 53.1 348
2.0 48 66.6 15-S-20 6 Texapon Tergitol 1.86 53.2 152 6.0 75 92.9
NSO 15-S-20 7 Disponil Disponil 1.86 53.3 600 3.0 175 78.4 FES 32
IS 3065 8 Disponil Disponil 1.86 53.3 490 4.0 200 72.6 FES 32 IS
1080 9 Disponil TD-3 1.86 53.0 318 2.0 110 no data FES 32 IS 10
DOSS Tergitol 1.86 57.0 86 1.0 135 47.3 15-S-20 11 DOSS Tergitol 1
53.4 372 0.5 100 34.2 15-S-20 12 DOSS Tergitol 3 53.1 54 1.0 35
35.7 15-S-20 13 DOSS Tergitol 0.33 53.3 116 0.5 130 43.7 15-S-20 14
DOSS Tergitol 0.67 60.3 474 1.5 105 84.8 15-S-20 15 Tergitol
Tergitol 2 55.8 600 10 68 72.1 15-S-3 15-S-20 sulfate 16 DOSS
Tergitol 0.67 60.5 228 3.5 90 61.4 15-S-3 17 EST-30 Makon 2 54.2
810 1.5 67 78.7 TD-3 Disponil FES 32 IS = sodium laureth sulfate
containing 4 moles of ethylene oxide, supplied by Cognis Tergitol
15-S-20 = a secondary alcohol ethoxylate containing 20 moles of
ethylene oxide, supplied by Dow B-330S = sodium laureth sulfate (3
moles) supplied by Stepan Rhodapex ES = sodium laureth sulfate (3
moles) supplied by Rhodia FES 993 = sodium laureth sulfate (1 mole)
supplied by Cognis Steol 4N = sodium laureth sulfate (4 moles)
supplied by Stepan Texacon NSO = sodium laureth sulfate (2 moles)
supplied by Cognis Doss = dioctyl sulfosuccinate Tergitol 15-S-3
Sulfate = secondary alcohol ethoxylate sulfate (3 moles) supplied
by Dow EST-30 = sodium trideceth sulfate (3 moles) supplied by
Rhodia Disponil 3065 = lauryl alcohol ethoxylate (30 moles)
supplied by Cognis Disponil 1080 = lauryl alcohol ethoxylate (10
moles) supplied by Cognis Makon TD-3 = tridecyl alcohol ethoxylate
(3 moles) supplied by Stepan
[0034] The peel value and wet tensile data show that the binders of
Runs 1-2, 4-8, and 14-17 can be considered for use as binders in
crepe processes, especially DRC processes. The binders of Runs
10-13 would be inappropriate for consideration as potential binders
in crepe processes because the 30-second wet tensile strength is
less than 55% of the ultimate wet tensile strength of the binder.
Without cure data, Runs 3 and 9 are questionable for use in a crepe
process.
* * * * *