U.S. patent number 3,868,205 [Application Number 05/341,464] was granted by the patent office on 1975-02-25 for embossed paper toweling and method of production.
This patent grant is currently assigned to Kimberly-Clark Corporation. Invention is credited to Gordon D. Thomas.
United States Patent |
3,868,205 |
Thomas |
February 25, 1975 |
EMBOSSED PAPER TOWELING AND METHOD OF PRODUCTION
Abstract
Absorbent paper sheets in multi-ply web form in which the outer
webs of the sheet are creped and consist of a series of ribs and
grooves. The webs have their ribs secured together by adhesive
dispersed in a pattern consisting of individual adhesive zones. The
adhesive zones are obtained by providing in embossing apparatus
cooperable rolls each having alternating ribs and grooves, the ribs
of one roll being provided with protuberances and the other with
recesses. The protuberances cover a relatively small area of the
total rib area and carry a web on the protuberances through an
adhesive applicator so that a relatively small area of the web
receives adhesive for attachment to a second web.
Inventors: |
Thomas; Gordon D. (Neenah,
WI) |
Assignee: |
Kimberly-Clark Corporation
(Neenah, WI)
|
Family
ID: |
23337684 |
Appl.
No.: |
05/341,464 |
Filed: |
March 15, 1973 |
Current U.S.
Class: |
425/363; 156/555;
425/500 |
Current CPC
Class: |
B31F
1/07 (20130101); D21H 27/40 (20130101); B31F
2201/0728 (20130101); Y10T 156/1741 (20150115); B31F
2201/0766 (20130101); B31F 2201/0761 (20130101); B31F
2201/0735 (20130101); B31F 2201/0787 (20130101); B31F
2201/0738 (20130101) |
Current International
Class: |
B31F
1/07 (20060101); B31F 1/00 (20060101); D21H
27/40 (20060101); D21H 27/30 (20060101); B44b
005/00 () |
Field of
Search: |
;156/209,462,472,471,469,292,219,210,205,555 ;264/286,282
;161/148,116,DIG.3,127 ;72/196 ;29/2B ;117/10
;118/44,200,221,224,225 ;425/296,403,369,363,336 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lesmes; George F.
Assistant Examiner: Silverman; Stanley S.
Attorney, Agent or Firm: Kimberly-Clark Corporation
Claims
I claim:
1. In embossing apparatus, a pair of cooperable embossing rolls
each having a series of ribs and grooves extending continuously
lengthwise of the rolls, the ribs being spaced apart
circumferentially by the said grooves disposed about the roll
periphery, the ribs of one roll each having a plurality of surface
land areas also extending longitudinally on the ribs and
projections of these ribs extending above the land areas and
separated longitudinally by the land areas and peripherally from
projections of adjacent ribs by the said grooves, the ribs of the
other roll having surface land areas extending longitudinally on
the ribs and recesses of the ribs lying below and separated by
these latter mentioned land areas for mating with the said
projections, and the projections of the one said roll in the
rotation of the cooperable embossing rolls being receivable in the
mating recesses of the other said roll, the said recesses being
shallow relative to the depth of the ribs.
2. Embossing apparatus as claimed in claim 1 in which the land
areas of the ribs of the one said roll are of greater length along
the ribs than the projections separated by the land areas and the
projections have a height of about 0.005 inch.
3. Embossing apparatus as claimed in claim 1 in which the
projections and recesses as viewed in plan are rectangular and the
projection and recess at each end of a rib is triangular.
4. Embossing apparatus as claimed in claim 1 in which the
projections and recesses are generally conical in shape and each
lies wholly within the width of the rib which accommodates it.
5. Embossing apparatus as claimed in claim 1 in which each of the
ribs of each roll have projections, recesses and land areas, the
land areas of each roll separating the projections and recesses of
that roll and the projections of each roll being receivable in the
recesses of the other.
Description
BACKGROUND OF THE INVENTION
This invention relates to multi-ply absorbent, soft paper products
useful as towels, napkins, wipes and the like. The invention is
also concerned with methods and apparatus for attaining such
absorbent paper products utilizing an efficient, suitable and
generally minimal amount of adhesive to secure attachment of creped
tissue webs to form a multi-ply sheet product.
It is known to provide embossed webs and to laminate them into the
form of a sheet by adhesive attachment on a commercial basis. This
may be done by any of several methods. One common method is to
apply adhesive to the embossment surfaces of one of the webs of a
sheet product and uniting at the embossment surfaces of the other
web. In this instance for a two-ply web, each web is separately
embossed and remains in contact with their respective separate
embossing rolls. Adhesive is applied in a thin layer to the
embossment surfaces of one of the webs with commercially available
adhesive applicating equipment and both webs are joined at their
embossment surfaces in the nip formed by the mated steel embossing
rolls. This method provides a high bulk product having good quality
ply attachment and works satisfactorily with discrete peg types of
embossing patterns. With other types of embossing patterns,
particularly gross patterns consisting of continuous line or
embossed line patterns, this method results in application of
adhesive to the entire land area of the sheet embossments, even
though adhesive attachment may be obtained at a small portion of
the total embossed land area, by utilizing for embossing, roll
patterns which are in crossing relationship. The result is the use
of more total adhesive than necessary for ply attachment purposes,
which increases the product cost and also stiffens the product
structure.
The present invention is an improvement on prior art practices in
that adhesive is applied in well spaced adhesive zones, and the
adhesive zones define embossments which are superposed on more
gross embossments of the web product. This is accomplished by
securing the webs together in a combining nip formed by a pair of
cooperable embossing rolls having particular characteristics. The
embossing rolls for the purpose each have a series of alternating
ribs and grooves disposed about its periphery; the ribs of one roll
have land areas and projections extending above the land areas
separated by the land areas, and the ribs of the other roll have
land areas and recesses lying below and separated by these last
mentioned land areas of the second roll. The projections of one
roll in the rotation of the rolls is receivable in mating recesses
of the other said roll. In a further embodiment each of the rolls
may have projections which cooperate with the recesses of the other
roll.
The projections of the embossing roll support a web for the receipt
of adhesive only in the zone of the projection. Since such
projections may be conveniently formed by etching, grinding or the
like to a very small size, the adhesive application in an adhesive
zone may be quite readily limited. Such leads to good flexibility
in the webs and final sheet and is conserving of adhesive.
Another advantage for the above embossing and combining method is
that it results in a product having an esthetically pleasing
appearance. The use of continuous line types of embossing patterns
produces a product having the same appearance on both sides. With
some types of line patterns, the product may lack attractiveness
because of the gross nature of the embossments. By providing the
continuous lines embossments of one web with spaced projections and
the other with spaced recesses, a more textured or woven type
appearance is obtained in the product. The laminated product still
has the same general appearance on both sides. However, the
embossment line recesses on one of the webs prior to lamination
become slightly raised projections as received in the finished
product. Similarly, the embossment line raised projections of the
other web become slight recesses after lamination in the finished
product. These projections and recesses being confined to the
continuous line embossments area tend to break up the continuity of
the embossments and result in a more pleasing pattern appearance.
In fact, the product attains somewhat of a woven fabric
appearance.
The invention will be more fully understood by reference to the
following detailed description and accompanying drawings
wherein:
FIG. 1 is an enlarged and fragmentary view in side elevation
illustrating the relationship of the combining rolls of the
apparatus with the creped tissue sheets of the sheet material at
the combining nip;
FIG. 2 is a fragmentary view in perspective of the combining rolls
only illustrating the cooperative relationship of the spirally
contoured rolls and their male and female segments;
FIG. 3 is a view in side elevation of embossing apparatus useful in
the production of a preferred embodiment of the sheet material and
illustrating particularly a four-roll stack having rolls similar to
those illustrated in FIGS. 1 and 2;
FIGS. 4 and 5 are respectively fragmentary views on a somewhat
enlarged scale of the combining rolls of FIG. 3;
FIG. 6 is a perspective view of the sheet material with the upper
web stripped back from the lower web to reveal the adhesive pattern
of the sheet;
FIGS. 7 and 8 are views schematically illustrating useful adhesive
patterns in the practice of the invention, the view in FIG. 7 being
similar to that of the structure shown in FIG. 6;
FIG. 9 is a view similar to that of FIG. 3 but illustrating a roll
arrangement for the production of a three-ply sheet product;
FIGS. 10 and 11 are respectively enlarged fragmentary views of the
upper and lower combining rolls of the structure of FIG. 9;
FIG. 12 is a view in perspective of a three-ply sheet (with the
arrow indicating the direction of travel to the product through the
combining rolls of FIG. 9) having the upper and central plies
partially turned back to reveal the adhesive patterns;
FIG. 13 is a schematic view in plan illustrating more specifically
the adhesive patterns of the structure of FIG. 12;
FIGS. 14 and 15 are fragmentary views of a further embodiment of
the invention illustrating cooperating upper and lower combining
rolls having a different form of mating segments; and
FIG. 16 is a fragmentary view in section of a product passing
through the type of combining rolls illustrated in FIGS. 14 and
15.
Referring now more in detail to the drawings, the numeral 10 (FIGS.
1-3 inclusive) designates an upper metallic combining roll which
cooperates with a similar lower metallic combining roll 11. The
composite sheet which issues from the nip between the combining
rolls 10,11 is formed of an upper creped paper tissue web 12 and a
lower creped paper tissue web 13. The upper web 12, as it
approaches the nip between the combining rolls, is provided with an
adhesive pattern as is most clearly indicated at 14 in FIGS. 1 and
6.
The upper combining roll 10 is provided with spirally extending
ribs 15 (FIG. 2) spaced apart by grooves 16. The ribs 15 are
generally rectangular in cross-section, extend at 45.degree. to the
direction of sheet travel through the rolls 10,11, and are provided
over their length with a series of protuberances 17 which extend
above land areas 18 separating the protuberances. The protuberances
17, as is most clearly shown in FIGS. 2 and 4, have a generally
rectangular configuration as viewed in plan except at the roll ends
where the protuberances terminate the roll and have a triangular
configuration as indicated at 17a. The land areas 18 are of greater
length in the embodiment illustrated than the projections 17.
The lower combining roll 11 has ribs 19 which are generally
rectangular in cross-section and separated by grooves 20 (FIG. 5).
The ribs 19 over their length are provided with a series of
recesses 21 also rectangular as viewed in plan spaced apart by land
areas 22 of greater length than the recesses. The ribs 19 extend
also at 45.degree. to the direction of sheet travel. The roll ends,
as indicated in FIG. 2, are terminated in the area of the ribs 19
by recessed portions of triangular shape 21a.
The rolls 10,11 rotate in the direction indicated by the arrows
(FIG. 2). The ribs 15,19 extend transversely to each other and,
suitably, the ribs have a width of between about 0.015 and 0.050
inch. The grooves 16 and 20 preferably have a somewhat greater
length in a direction perpendicular to adjacent ribs and are of
about 0.015 to about 0.125 inch. The ribs, while generally
rectangular in cross-section, suitably have slightly angled sides
to facilitate web movement into the grooves.
Referring now particularly to FIGS. 4 and 5, the projections 17 are
designed in the operation of the rolls in the manner illustrated in
FIG. 3 to enter into the recesses 21. The recesses are specifically
made quite shallow to minimize distortion at the recess edges of
webs forced into the recesses by the action of the projections 17.
The projections and recesses need, for example, be only about 0.005
inch. Two plies of the web material each of thickness of about
0.001 inch are slightly compressed by the action of the combining
rolls in the manner illustrated in FIG. 1 to insure of good
adhesive contact of the webs 12,13.
As will be clear from a consideration of FIGS. 4 and 5, the
protuberance b of roll 10, for example, mates with the recess b' of
roll 11; similarly, the triangular protuberance c cooperates with
the triangular recess c'.
The webs 12,13 (FIG. 3) are directed to the combining rolls 10,11
respectively over rolls 23,24. In the formation of a two-ply sheet
the adhesive is applied to the upper traveling web 12 as
illustrated in FIG. 3. The liquid adhesive material designated at
25 is fed by a fountain roll 26 to a metering roll 27 in thin film
form and transferred to roll 28. The roll 28 engages the traveling
web on the combining roll 10 only at the protuberances 17,17 a so
that only a minor area of adhesive relative to the web area is
added to the traveling web 12 (FIG. 6). The pattern of the adhesive
in a preferred embodiment is clearly shown in FIG. 6. The lower web
13 in FIG. 6 also shows the presence of adhesive in the stripped
back zone for the reason that some adhesive will adhere to the
lower ply 13 when the strip back action is effected. Most
importantly, however, the adhesive is only applied in well spaced
areas where pressure application by the protuberances 17 on
material in the recess 21 is effected and all adhesive employed
serves in a bonding action.
Essentially as illustrated in FIG. 7, the sheet may have an area of
about 9 percent of the total to which adhesive has been applied. If
a more flexible sheet is desired, the adhesive may be reduced and
FIG. 8 illustrates a pattern which is generally sinusoidal and
suitable for this latter purpose. The adhesive is shown at the
cross-over points of the sinusoidal embossments of overlying webs.
In the arrangement of FIG. 8 the area having adhesive is about 4
percent of the total area of one sheet.
In order to produce a three-ply product, it is desirable to apply
the adhesive to each of the outer plies of the three-ply web in
much the same manner as adhesive has been described as applied to
the two-ply web of FIG. 6. Thus, as illustrated in FIG. 9, the
creped paper web 13' which is combined at the nip between rolls 10'
and 11' with the creped paper web 12' is itself adhesively treated.
For this purpose a flexographic adhesive printer similar to that
described in connection with FIG. 3 is provided; this mechanism
includes the pond of adhesive 25', fountain roll 26', metering roll
27', and transfer roll 28'. The middle ply of the three-ply web
product is indicated at 30 (FIG. 9) and receives adhesive from each
of the outer plies as may be clearly seen from FIG. 12. This middle
ply may be a strengthening web such as a scrim, an uncreped web or
a creped web similar to the outer webs.
The adhesive pattern of the structure of FIG. 12 is, however, quite
different than that previously mentioned in connection with FIGS. 6
through 8. The different adhesive pattern is obtained by the
provision of engraved rolls such as indicated in FIGS. 10 and 11.
The roll 10' has a series of spirally extending lands and grooves
and the lands are configurated as follows. The land portion
designated by each numeral 31 provides projections similar to those
mentioned in connection with roll 10. An end projection of
triangular form is shown at 31a. Each projection 31 lies adjacent a
planar portion 32 of the land and a recess 33 of a land also lies
adjacent each land portion 32. In the upper roll 10', then, each
land has three levels. Thus, each projection 31 of a land is
bounded by a planar portion of the land and each recess is also
bounded by a planar portion of a land except at roll ends; the
projection and recesses at the roll ends alternate around the roll
periphery.
The lower roll 11' (FIG. 11) is provided with lands which have
either recesses or projections. The numeral 34 designates the land
areas of each rib. The recesses from the level 34 are designated at
35 and 35a while projections from level 34 are indicated at 36 and
36a. As is clearly seen from the drawings, the projections of roll
10' cooperate with the recesses of roll 11' in a manner similar to
that described in connection with FIGS. 4 and 5. The recess at f,
for example, cooperates with the projection f' of roll 11'. By this
arrangement the projections of roll 10' and the projections 36 of
roll 11' receive the adhesive as the sheet 12' and 13' travel to
the combining nip (FIG. 9). Much less adhesive is required while
yet permitting the attainment of well adhered plies. The adhesive
pattern as applied to the upper sheet 12' is illustrated at 40
(FIG. 12) and that retained by the middle ply upon separation is
indicated at 40'. Similarly, the adhesive zone applied to the lower
ply 13' is indicated at 41 and that retained by the middle ply on
separation is illustrated at 41'.
FIG. 13 schematically sets forth the adhesive arrangement for a ply
of the structure of FIG. 12 and, as is clearly shown, each outer
sheet has adhesive on it to the extent of about only 4 - 5 percent
of its surface area.
A further embodiment of the invention is illustrated by the FIGS.
14 through 16 inclusive. The numeral 42 (FIG. 14) designates an
upper combining roll of a pair, the lower roll being indicated by
the numeral 43. The upper roll has a series of ribs 44 separated by
grooves 45 while the lower roll has a series of ribs 46 separated
by grooves 47. Projections 48, generally conical in shape, well
spaced along the length of the ribs 44, mate with generally conical
depressions 49 spaced along the length of the ribs 46. As will be
obvious from the foregoing, the function of the projections 48 in
the furnishing of a two-ply sheet is to support the upper web as it
receives the adhesive in the forming of the two-ply structure in
the same manner as has been described in connection with FIGS. 1
through 7. However, in this instance the individual adhesive zones
may be small in diameter though preferably the recesses or
depressions 49 should be maintained shallow to avoid web distortion
in the adhesive areas.
Very pertinent to the practice of this invention is the saving in
adhesive which makes for an economical product. Further, the fact
that much of the area of the sheets does not require adhesive
provides for minimal stiffness of the product. Additionally, the
adhesive zones may be spaced well apart on any given land area of
the product.
EXAMPLE 1
A toweling material was produced by directing base webs to the
equipment arrangement of FIG. 1. Such webs suitably have a dryer
basis weight of about 9-12 pounds per 2,880 square feet and a
stretch at break in the range of 20-35 percent. The adhesive
supplied to the upper web was polyvinyl alcohol. Other adhesives
may, of course, be employed. The spiral pattern of the rolls had
lands about 0.030 inch wide and extended continuously at a
45.degree. angle with respect to the axis of the roll. The depth of
the ribs and the distance between ribs was about 0.070 inch.
Engraving the lands into recesses and projections reduced the land
area of the sheet containing adhesive from 30 to 9 percent. This
reduces the amount of adhesive applied by a factor of over 3 to 1.
Resulting laminated product produced by this method had good bulk
characteristics, embossing pattern definition and acceptable ply
attachment for towel use. Ply attachment values of 10 gms. per 4
inches and up were possible, depending on the amount of adhesive
applied and the combining nip pressure between the two engraved
steel embossing rolls. Ply attachment was determined by cutting a
four inch wide sample by about a 6-inch length, separating the two
outer webs on a portion of the sample, and then placing those
4-inch wide separated web portions in an Instron tester to measure
the force required for ply separation.
EXAMPLE 2
Two and three-ply towel weight samples were prepared using the
above spiral rib embossing pattern, prior to and after engraving
the cross-over points. For the two-ply samples and the outer
surface plies of the three-ply samples, a creped tissue web having
a dryer basis weight of 10-11 pounds per 2,880 square feet and a
stretch at break of about 32 percent was employed. For the center
web in the three-ply samples, a creped tissue web having a dryer
basis weight of about 6-7 pounds per 2,880 square feet and a
stretch at break of about 100 percent. The following shows test
results on these samples.
______________________________________ Engraved Cross- Straight Rib
over Points 2 ply 3 ply 2 ply 3 ply
______________________________________ Finished Basis Weight --
(lbs/2880 sq. ft.) 26.7 41.8 23.8 38.8 Dry Tensile Strength --
(gms./3") MD 4417 4860 3500 4117 CD 1491 2958 1950 2533 % MD
Stretch 10 16 19 18 Handle-O-Meter -- MD 10.1 19.1 6.3 11.5 CD 14.9
20.5 10.4 17.6 ______________________________________
The Handle-O-Meter values show the improved limpness for the
samples produced when the cross-over points were engraved, which is
the result of reducing the adhesive coverage on a large portion of
the continuous spiral rib lands.
The Handle-O-Meter values were obtained by using a common
Thwing-Albert Handle-O-Meter test. For test purposes to obtain the
Handle-O-Meter value in the machine direction, 21/2 inches wide
.times. 6 inches long samples were used, and for cross direction
samples were 21/2 inches wide .times. 31/2 inches long. The
Handle-O-Meter values give an indication of sheet stiffness and
lower values indicate better handle and less stiffness.
In most instances the application of adhesive to the extent of
about 5 percent of the sheet area is suitable if the projections of
the roll which receive the adhesive are well and uniformly spaced.
The pattern and base tissue weight chosen for the final product
influence the amount of adhesive applied to the sheet. With heavier
weight sheets and more gross patterns usually a greater amount of
area of the sheet is occupied by adhesive to insure of good
laminate characteristics. The situations found particularly useful
are those in which 10 to 50 percent of the rib surface area is
constituted by projections for receipt of adhesive.
For a three ply sheet where the projections and recesses alternate
on one land of each roll, the same principles are applicable but 5
percent to 25 percent of the rib surface area will be projections
but, of course, adhesive is then applied to both outer sheets.
As many apparently widely different embodiments of this invention
may be made without departing from the spirit and scope thereof, it
is to be understood that I do not limit myself to the specific
embodiments thereof except as defined in the appended claims.
* * * * *