Note: Descriptions are shown in the official language in which they were submitted.
132~909
IMPROVED HAND GR WIPER TOWEL
Technical Field
This invention relates to an improved paper towel.
More particularly, this invention relates to a more
absorbent hand or wiper towel and a process ~or its
manufacture.
Background
Disposable paper towels are commonly manufactured and
wid~ly used. A primary function of these towels is
absorbing liquid. Paper towels possess varying degreec of
certain qualities which make them suitable for different
tasks. Some of these qualities are softness, absorbent
capacity, absorbent rate, and strength. The absorbent
capacity is the maximum amount of liquid a paper towel can
absorb, and the absorbent rate is the speed with which the
paper towel can absorb liquid. The strength of paper a
towel is generally the tensile strength of the paper towel
which is a measure of the stress required to pull the
paper towel apart.
Hand or wiper towels are a particular type of paper
towel and are often used in washrooms for drying hands and
for cleaning up liquid spills. These towels are also used
for wiping surfaces clean with a solvent such as in
washing windows or counter tops. Accordingly, towels must
'3~'
r
2 1 ~ 2 ~
absorb relatively laJge ~uantities of liquid veIy quickly and
poss~ss enough strength so ~hat ~hey do not bre~k apart when
subjected to stress even when ~e towe]s are saturated wi~
liquid. Purther, it is also desirable ~or hand or wiper towels
s to be soft, pa~ticularly when ~e towels are used for drying
h~nds so d~at they are comfo~able to the user's skin and
when wiping finished surfaces~ such as ~e~k tops or
aut~mobile exte~iors, so ~at the towels do not ~cratch ~e
finished ~aces.
0 Prior art hand or wiper towels which ar~ made
from cellulosic fibers are no~n~lly strong even when
saturated with liquid, but orten lack desirable levels of
absor~nt capaci~r, absorbent rate, and softness. These prior
art towels are generally made wi~ ~l conventional wet
fonning process wherein the beginning fumish contains
chemical bonding agents to bind ~e celllllosic fibers together
and p~otnote the ~trength of dle towel. The fu~nish is
deposited on a ~aveling foraminou~ belt ~ere~y fo~ning a
web of moist cellulosic ~Ibers on top of ~e for~minous belt.
~0 The mois~ ~Ibrous web is transfened to an ab~orben~ carrier
belt and ~en pressed by one or a selies of rollers to remove
water from the ~Ibrous web al~d to compact d~e ~ e
- web t~ ther promote the stFen8th of the towel. The
pressed flbto~s web is transferred to ~ ouhr surfa~e of a
2S rotat~ng steam-heat~d dryer where~y part of the remain~ng
water ig evaporated ~rom the flb~ous web. The ~Ibrous web
is ~en "creped" by a blade positioned adja~ent th¢ out~r
surface of ~e d~er whioh scrapes the partially~ ed fibrous
web from ~e outer surface of ~be dryer. Tho creped ~Ibrous
wcb is ~en conveyed over a selies of steam-heated d~ye~s to
evaporate the 20-S0% moistur~ rema~ning in dle web af~er
creping. The creping enhances the absorbent capacity and
abso~ t ra~ of ~e towel
The conventional p~Ç8S for malcing ~oft paper
towels is similar to the conventional process for m~iking ~nd
.
_ 3 _ ~ 13249~g
or wiper towels; however, creping of the fibrous web is
done when moisture content has been reduced to 10% or
less. An adhesive solution is also applied to the outer
surface of the "Yankee" creping dryer so that the fibrous
web adheres tightly to the surface of the dryer. The
creped fibrous web requires no further drying in this
process. The resulting soft towels possess high levels of
absorbent capacity and absorbent rate; however, these soft
towels are also very weak and tend to break apart when
saturated with liquid. Accordingly, soft paper towels are
not an adequate substitute for hand or wiper paper towels.
According to one aspect of the present invention
there is provided a towel having an absorbent capacity of
at least 385%, and an absorbent rate of about 8 seconds or
less, the towel being prepared by forming a furnish of
cellulosic fibers, water, and a chemical debonder,
depositing the furnish on a first travelling foraminous
belt thereby providing a web on top of the travelling
foraminous belt, subjecting the fibrous web to
non-compressive drying to remove the water from the
fibrous web, and removing the dried fibrous web from the
travelling foraminous belt without creping the fibrous web.
Surprisingly, the towel prepared by the process of
the present invention, which does not involve a creping
step, possesses high levels of absorbent capacity,
absorbent rate, strength and softness.
According to one embodiment of the invention, the
first foraminous belt travels at a first velocity, and
there is included the further step of transferring the
fibrous web from the first travelling foraminous belt to a
second foraminous belt, the second foraminous belt
travelling at a second velocity up to about 10% slower
than the first velocity, thereby providing a series of
transverse folds in the fibrous web prior to subjecting
the fibrous web to non-compressive drying.
Another aspect of the invention resides in a towel
- 4 - 132490~
having an absorbent capacity of at least about ~00~, an
absorbent rate of about 6 seconds or less, a dry tensile
strength of at least 1800 grams, and a wet tensile
strength of at least about 380 grams.
Such a towel is prepared by a process comprising the
following steps performed in sequence, forming a furnish
of cellulosic fibers, water and a chemical debonder,
depositing the furnish on a first travelling foraminous
belt thereby forming a fibrous web on top of the
travelling foraminous belt, subjecting the fibrous web to
non-compressive drying to remove the water from the
fibrous web, removing the dried fibrous web from the
travelling foraminous belt without creping, and then
embossing the dried fibrous web.
Alternatively, such a towel can be prepared by a
process comprising the following steps performed in
sequence, forming a furnish of cellulosic fibers, water
and chemical debonder, depositing the furnish on a first
foraminous belt, the first foraminous belt travelling at a
first velocity, thereby forming a fibrous web on top of
the first foraminous belt, transferring the fibrous web
from the first travelling foraminous belt to a second
foraminous belt, the second foraminous belt, travelling at
a second velocity up to about 10~ slower than the velocity
of the first foraminous belt, thereby providing a series
of transverse folds in the fibrous web, subjecting the
fibrous web to non-compressive drying to remove the water
from the fibrous web, removing the dried fibrous web from
the second travelling foraminous belt without creping, and
then embossing the dried fibrous web.
Even more particularly, the towel of the present
invention is prepared by a process wherein the cellulosic
fibers in the furnish comprise secondary cellulosic
fibers. The high levels of absorbent capacity, absorbent
rate, strenqth, and softness are also achieved usinq the
secondary cellulosic fibers. This aspect of the present
invention is particularly advantageous because the cost of
B
~ 3 2 ~ 9 ~ 9
secondary cellulosic fibers is substantially less than the
cost of virgin cellulosic fibers.
Still more particularly, the towel of the present
invention is prepared by a process further comprising the
step of embossing the dried fibrous web after removing the
dried fibrous web from the travelling foraminous belt.
The embossing increases the absorbent capacity, absorbent
rate, and softness of the web, but tends to reduce the
strength of the web. Towels of the present invention
prepared by the process including the embossing step have
an absorbent capacity of at least about 400%, an absorbent
rate of at least about 6 seconds or less, a tensile
strength of at least about 1800 grams to about 2700 grams,
and a wet tensile strength of at least about 380 grams to
~5 about 680 grams.
Still more particularly, the towel of the present
invention is prepared by a process which includes the
steps of: (1) forming a furnish of cellulosic fibers,
water, and a chemical debonder; (2) depositing the furnish
on a first travelling foraminous belt, thereby forming a
fibrous web on top of the first foraminous belt; (3)-
transferring the fibrous web from the first travelling
foraminous belt to a second foraminous belt travelling at
a velocity from about 5 to 10% slower than the velocity of
the first foraminous belt, thereby providing a series of
transverse folds in the fibrous web; (4) subjecting the
fibrous web to non-compressive drying to remove water from
the fibrous web; and (5) removing the dried fibrous web
from the second travelling foraminous
~32490~
belt. The towel made from ~is p~icular process exhibi~s
even greatcr levels of stxength and softnes~ because of the
sene~ of folds in dle toweIs. The folds increase the streng~
of the towels by providing a degree of stretch, ~ereby
reducing the tendency of ~e towel to ~e~r when subjected to
str~ss. The folds in ~e towels increase the so~ness of the
towels by increasing ~e ~ickness of ~e l:oweL
Therefore, an object of ~e present invention is
to provide a~ improved hand or wip~r towel.
lo Ano~her obje~t of the pre~;ent invention is to
provide a hand or wiper towel with high levels of absorbent
capacit~, abso~ent rate, streng~, and sofmess.
~ fur~er objeet of ~e present invention is to
provide a hand or wiper towel at a reduce~ cost.
O~er objects, features, and advant~ges will
become apparent from reading ~e following specifications
in conjun~tion wilh ~e accompany~g drawings.
Brief Description oP Drawing~
~ig~ 1 is a perspective view of ~e process line
for pr~ducing a preferred embodimcnt of the prescnt
invention; and
;~ Fig. 2 i~ an enlarged soctio~al Yiew of the point
of transfer between ~e fo~ning belt and the through d~yer
belt in a proce~s line for producing another pre~erred
embodiment of ~e present inYention.
Detailed Oescription of the Prefer~ed Embodiments
Turnillg first to Pig 1, there i~ illustrated a
process line 10 for producing a pIeferred embodimeIIt of ~e
prcsent inverltion. The process line b~:gins witl~ a papcr-
making filmisb 12 comprising a mi~ture of secondary
cellulosic fiber, water, and a ~hemical debonder which is
deposited fr~m a conventional head bo~ ~not shown) ~rough
a r.o~zle 14 on top of a for~minous wirG ~orming belt 16 as
6 132~9~9
shown in Fig. 1. The fonning belt 16 tlavels around a pad~
de~lned by a series of guide rollers. l~e forming belt 16
travels fr~m an upper guide ~oller 20, posi~i~ned below and
proximate ~ ~e head box nozzle 14, horizon~ally and away
from dle head box no~zle to ano~her upper guide roller 22,
passes over ~e upper ~uide ~oller 22 and di~gonally ~nd
downw~rdly to a lower guide roller ~, passes under ~e
lower guide roIler 24 and diagon~lly and upwardly toward
~e nozzle 14 to a lower g~ide roller 2~i, passes over lower
guide ~ller 26 and diagonally and downwardly to lower
guide roller 28, passes under lower guide Iolle~ 28, and
tums upwardly and slightly inwardly to a guide roller 32,
passes behind the ~uide roller 3~ and upwardly and
out~1vardly retu~n~ to upper guide roller 7Ø
A ~acuum form1ng box 34 positioned benea~
the fom~ing belt 16 proxunate the opening 36 of ~e head box
no~zle 14 ~ediately extracts wa~er from ~e moist fibrous
web 38 deposited on top of the fomn~g belt by ~e head bo~c
nozzle. Ih¢ partially dewater~d ~;brous web 38 i~ earried by
the forming belt 16 in the counterclockwise di~ection, as
shown in ~ig. 1, towards the upper guide roller 22. The
fibrous web 38 a~ it moves away from the vacuum fo~ng
box 34 pre~er~bly comprises from aboul: 19% to abol~t 30%
cellulosic fiber by weight. An edge vacuum 40 positioned
2S below the folming belt 16 pro~imate to d~e upper guide
roller 22 is an aid to trimming the edges of d~e ~tbrous web
38.
The ~Ibrous web 38 passes over the upper guide
roller 22 and downwardly between ~e fc~rming belt 16 and a
~rough~ er bclt 42.
The ~rough-dryer belt 42 tl~vels around a pa~
deffned by a series of guide rollers. The through-dryer belt
42 travels ~rom a ~uidc roller 44 po~itioned above and
vertically of&et f~om guide roller 22 downwardly towards
~e fo~ning belt 16, contacts ~e ~Ibrous web 38, and fhen
~32;4~
downwardly and diagonally away from ~uide roller 24 to
guide roller 46, passeg under guide roller 46 and ~un~s
horizontally away from the forming belt 16 towards a
through-d~er guide roller 48, passes under the through~
s drycr guide roller 48 ~nd turns upwardly and over a
dlrough~dryer 50 and downwardly to another ~rough~ryer
guide roller 5~, passes under d~rough-dryer guide roller S5
and tu2ns horizontally away from the ~rough-dryer 50
towardg a lower guide roller 54, passe~: under lower guide
0 roller 54, and tums upwardl~ to an uppor guide roller 56,
passe~ over the upper guide roller 56 and turns slightly
downwar~ly to an upper guids~ roller 58, passes under the
upper guid~ roller 5~, and turns slightly upwardly in the
d~rection of ~e forming belt 16 to an ul~per guide rolle~ 60,
passes over upper guide roller 60 and tu1ns downwa~dly to ~
guide roller 62, passes unde~-guide roller 62 and turns
substantiall~ holizontally away ~rom fvrming belt 16 to a
guide roller ~4~ passes around guide r~ller 64 and turns
: horizontally in the direction of ~e fclrming ~elt 16 an~
returns to guide roller 44.
A ~acuum pickup 66 pulls the ~brous web 38
towards the through-dryer belt 42 and away from fonning
bclt 16 as ~e ~lbrous web passes between dle throu~h dryer
belt and ~e folming belt . The fibrous ~eb 38 ~dheres to ~e
through-dryer bell 4~ and is camed by ~e through-dryer
belt downwardly below lower guide roller 46 towards ~e
through-dryer S0. Yacuum boxes 68 positioned above and
;~ proximate to the ~rough-drger belt 42 between ~e lower
guide roller 46 and the through-dryor guide roller 48
fur~er extlact water from t~e moist fi6rous web 38. The
fibrous web 38 preferably compnses between about 25% ~nd
35~o filber by welght after passing beneath the vacuum bo~es
6~.
: ~ Thc through-dryer 50 ge~erally compr~ses an
oute~ rotatable perforated cylinder Sl and an outer hood S2
13~4909
for ncceiving ~e hot air blown ~rough ~e perfora~ons 53,
the ~Ibrous web ~8, and ~e through-dryer belt 42 as is
known to ~se skilled in the a~. The ~ough-dryer belt 42
car~es ~e fibrou~ web 38 over ~e upper portion of ~e
through-dryer outer cylinder 50. Th~ heated air fo~ced
~rou~h ~e perforations 53 in the outer cylinde~ Sl of ~e
through-dlyer 50, lemoves the remaining water ~om the
fibr~us web 3~. The tempe~atur~ of the air for~ed ~ougll
the ~Ibrou~ web 38 by the ~rou~h-dryer is preferably a~out
0 30~ to 350- P.
l~e through-dryer belt 42 ca~ies the dried
fibrous web 3~ below the throu~ll-dr~re~ guide roller SS
toward~ the lower ~guide roller ~4. The slried fibrous web 38
is pulled from ~e through~dlyer belt ~t lower ~uide roller
54 ~y a takeup roller 70. The dried fi~rous web 38 passes
from the ~rough-dryer belt 42 ~o a ~ip between a pair of
embossing rollers 72. The dried ~nd e~lbo~sed ti~rous web
38 then pasges from the nip betweel) ~c ~,mbossing rollers 7
to ~e takeup roller 70 whe~e ~e flbrous ~b is wound înto a
~o pr~duct ~oll 74.
1~ an even more preferred embodiment of dle
present ~nve~tio~, ~e pr~cess line 10 previously de~cribed is
- modified so that the through dryer belt 42 tra~els at a
velocity from about S to 10% slov~ver ~n dls velocity of ~e
as folming belt 16. Ag a result, ~e moist fibrou~ w~b 38
arrives at ~c point of transfer 7~ betw~en tlhe formin~g belt
16 and ~e t~rough-dryer belt 42 at a faster rate than the
fibrous wcb is carried away by thc ~ough-dryer belt . As
dle moist flbrous web 38 buiIds up at the point of t~nsfer 76~
dle moist fab~io tends to bend into a sçries of transverse folds
78 as shown in Fig. 2. The folds provide for ~ degrec of
stretch in ~e fibrous web ~ereby ~ncreasing the overall
strength of the filbrou~ w~b, and because ~e folds stack on
~op of one ano~er, ~e ~Ibrolls web bccorncs dlicker and ~us
3~ ~oftcl.
132490~
vention is further illustrated ~y the
following example u~hi~h is illustrative of a preferred
embodiment desi~ned to teach ~ose of o~din~ry skill in ~e
art how to practice ~is in~ention.
s
Example 1
An initial paper-making furnish is prepared
comprising 0.15% by weight of secon~lary cellulogic ~Iber
and ~.85% water, The seeonda~y cellulosic ~Iber used in
lo ~e fun~ish comprises a mixture of 80% cup stoclc ~Iber and
20% deinked wastepaper. 20 wet lbs. of Berocel 584
debonder, a ~urfa~tant manufactured by Berolchemie AG,
per t~n of dry seconda~r cellulosic ~ber is added to the
initial furnish mixture. 11.4 dry Ibs. o~ K~mene 557 H wet
lS s~rength resin, a polyamide epichlorohydrin resin
manufactured by ~ercules and 500 ml. of Stero~ D~, a
rewettin~ agellt m~nufactured by Mons~nto, ar~ also added
to each dry ton of the initial fumish resulting i~ a ~u~nish
with a CanadiaI~ Standard Freeness of 410 cc.
~0 The fînal fumish is deposited from a head box
through a 114 i~. wid~ opening onto ~ g4 M Appleton
forming web, manufactured by Appleton Wire. The
folming belt travels at a velocity of 40 ft. p~r minute. The
deposited fumish forms a web of cellulosic ~Ibers with a dry
:; 25 basis weiBht of 46 grams per sq. me~r on top of ~c forming
:: belt.
Immedhtely after the fîbrou~ web is forMed on
top of ~e forming bclt, the ~Ibrous web passes over a
folming box vacllum which oper~tes at a pnssure of 8 ~n. H8
below a~nospheric pressure and extracts water from the
fibrous web. The ~Ibrous web ~en passes over an ed~e
:~ vacuum which operates at a vacuwn of 11-15 in. Hg below
atmospheric pn~sure and ~urther trims ~e edges of the
~Ibrou~ web.
The i~lb~us web i8 ~en tr~nsferred to a 31 A
''` 10
1324909
Albany tllrough-dryer belt, manuf~ctured by Albany
International, with ~e aid of a ~acuuln pickup which
produces a v~cuum of 11-15 in. Hg below atmospheric
pressur~. The through~dlyer belt also travels at a velo~ity of
40 ft. per minute. The consistency of thl~ partially dewatered
fibro~s web after the transfer to the througll-dryer belt
contains 19% b~ weight of dry cellulosit: fiber.
The through-dryer belt carries the par~ially
dewatered ~lbrous web over a pair of vacuurn boxes each
producing a vacuum of 14 i~. Hg below atm~spheric
pressure and fur~her dewaters the fibrous web. The
through-dryer ~elt then carnes ~e fibrous web around the
upper portion of a c~lindrical through~dryer. The ~Ibrous
web plior to transfer to a~e d~rou~h-dJyer comprises 26% to
27% by weight of cellulosic fiber. l~e ~rou~h~yer forces
air at a temperature of 33S' F throu~h ~e fibrous web and
removes the r~main~ng water from ~. fibro~s web. The
dried ~lbrou~ web is pulled di~ectly from t~he ~rough-dryer
belt for u~ ~s a hand or wiper towel.
A towel produced according to the
speci~lcations in ~xample 1 was subjected to a se~ies of tosts
to det~nnine ~e a~sorbency and s~eng~ of the towe~ ~nd is
- ~ndicated in Table 1 as Bxampl~ 1 base towel. The base towel
from Example 1 w~s also subjected to post-treatrnent
embossing ~ollowed ~y ~e same series of tests. A pOniOn of
the E~tample 1 bas¢ towel was em~ossed with Kimberly
Clar~ Embossing PattcrD 1 (Northen~ E~ngra~ing Pattern
No. 1804) and anothet portion of ~e E~;ample 1 base towel
was em~ossed wi~ Kimberly Clark Pattern 2 (Nor~ern
Engravirlg Pattorn No. 1557). Tho resulls of tests performcd
on ~c embossed ~owels i8 also shown ~n Table 1. nlrec prior
art hand c~r wiper towels, the Scott 180, the Po~t Howard
202, and the Cr~wn Zellerbach 820, wcrc also subjected to
the sam8 tests as ~e Bx~rnple 1 basc tow~l. ~e results of d~c
3S tests perfonn~d on ~he p~ior art towcls a~e also shown in
~32~90~
Table 1 for ~omparative pUlpOSÇS.
The basis wei~h~ of ~e towels shown in Table 1
was de~m~ed according to ASTM D3776-g and is shown
in units of pounds of dry towel per 2,~80 sq. ft. of towel.
S The water capacity of the towel~ in Tabl~ 1 wa~ mea~u~ed
accordin~ to federal specification UU T-595C ~nd is showrl
as ~e percent of ~e weight of ~e towel which ~e towel can
absorb in wei~ht of water. The ~ater ~&te of the towels in
Table 1 was measured according to TAPPI (Te~hnical
As~ociation of ~e Pulp and Paper Industry~ T432 SU~72.
~e wa~er rate is shown in Table 1 as ~e number of seconds
for a 4" x 4" towel to become satura~:d wi~ water. The
thiek~ess of the towel is mea6u~ed a¢cording to TAPPI
T411-68 and is shown in inches ill Tflble 1. The ~ens;le
s~reng~s of ~e towel~ shown in Table 1 a~e mea~ured
according to ~STM r~ 7-6 and r)1~82. The ten~ile
strength is ~e amount of stress re~,ui~ed to pull a 3~ len~dl
of towel apart. The tensi~e streng~s shown iII Table 1 are
expressed in ~rarns. The tensil~ s~eng~s of d~y towels were
measured in both ~e machine direction and ~e ~ross
di~ection. The tensile strengdls of th~ ~owels saturated with
water wer~ measu~ed in ~e cross direction.
: `
~, .
~32~909
T~BI~
Fort C~wn ~xqrnple Embossed~mbossed
How~ Ze~le~h ~ase Basc TowelBRse Towel
Scott 180 20~ 820 Towel K-C Pa~ 1K-C Pat. 2
Basis Weight,27 27 2~ 27 27 27
#/2880~2
Abso~bant 284 270 2~S 385 3~ 505
Capacity, 9rO
Absorb~nt Rate, 35 58 6~ R 6 4
Swo~d~
~liCkllGSS, 0.0~420,00430.00460.0077 0,00~Q()0~3
~ches
Tcnsile Slren~
MD D~y, g 7480 ~ 690 10890 6078 ~679
G~ ~r g 3460 3470 2640 S738 2421 1889
CDWetg 1163 ~S0 8~0 1481 6~3 387
~3 13249~9
A~ shown in Table 1, the 13x~mple 1 b~s~ towel
possesses a superior absorbent c~paGity to o~er halld or
wiper ~owel~ which comprise ~ sam~: or about the ~an e
basis weight as ~e ~3xample 1 base towel. The ab~orbent
capaci~ of th~ Example 1 base towel as sh~wn in Table 1 is
gO% greater than any of ~e prior art towels also sh~-~rn. The
Example 1 ba~e towel also possesses a superior level of
absorbent rate ~han the prior ar~ towels shown dlerein. The
abso~ t late of ~e Example 1 base towel is at leas~ 4 times
0 faster than any of the prior art towels shown 1n Table 1. The
Example 1 base towel also possesses a greater ~ickness than
~hose prior a~t towels shown in Table 1 and ~us is a so~ter
towel. Fur~er, ~e tensile strengd~ of the E~xample 1 baso
towel is superior to the tensile st~engd~s of the pnor ar~
t~wels shown m Table 1.
The embossed ~xample 1 base towels possess
eve~ higher levels of absor~ent capaei~ and abgor~ent rate
as shown in Table 1. The tensile strengths of the embossed
;Eixample 1 base towels are reduced somewhat by the
embossing bllt remain comparabl~ to ~ tensile streng~s of
~e prior art towels shown in Table 1.
In su~y, ~e d~ n Ta~le 1 show that hand
or wiper towels which are prefe~ed embodiments of ~e
:~ ~ pr~sent invention pos~ess superlor levels of absorbent
capaci~, ab~orbcnt rate, ~oftness and st~ngth to o~er p~ior
a~t h~d or wiper towels o~ ~e sam8 or about the same basis
weightO
It should be understood that the for~going
relates only to preferr~d embodiments of ~he present
in~ention, and that numerous changes and modifi~ations may
be made without depatting from ~e spirit and scope of ~e
in~entdon a~ d~med in ~e followmg claims.
'~ ,
