U.S. patent number 3,615,976 [Application Number 04/708,097] was granted by the patent office on 1971-10-26 for method of producing a high bulk macro-crepe product.
This patent grant is currently assigned to Kimberly-Clark Corporation. Invention is credited to Dan D. Endres, Frank M. Lewis, Jr..
United States Patent |
3,615,976 |
Endres , et al. |
October 26, 1971 |
**Please see images for:
( Certificate of Correction ) ** |
METHOD OF PRODUCING A HIGH BULK MACRO-CREPE PRODUCT
Abstract
The production of a high bulk cellulosic wadding product which
involves the dampening, preferably to a well wet stage, of creped
padding secured by adhesive in well spaced zones to a drawn
synthetic fiber web. The drawn fiber is substantially unaffected by
the dampening while release of crepe distends the tissue between
adhesive zones providing a macrocrepe structure on the creped
tissue, the bulked nature of the tissue being retained upon
subsequent drying. The process most suitably is carried out on an
assembly of cross-laid composites of the tissue and fiber. The
product is characterized particularly by bulk, strength and
softness and has utility in applications such as that of
facecloths.
Inventors: |
Endres; Dan D. (Neenah, WI),
Lewis, Jr.; Frank M. (Neenah, WI) |
Assignee: |
Kimberly-Clark Corporation
(Neenah, WI)
|
Family
ID: |
24844365 |
Appl.
No.: |
04/708,097 |
Filed: |
February 26, 1968 |
Current U.S.
Class: |
156/83; 156/178;
156/179; 156/182; 156/183; 156/277; 156/292; 428/113; 428/198;
428/361; 428/393; 428/394; 428/152 |
Current CPC
Class: |
D04H
3/04 (20130101); D04H 1/593 (20130101); Y10T
428/2967 (20150115); Y10T 428/24124 (20150115); Y10T
428/24826 (20150115); Y10T 428/24446 (20150115); Y10T
428/2965 (20150115); Y10T 428/2907 (20150115) |
Current International
Class: |
D04H
13/00 (20060101); B32b 031/00 () |
Field of
Search: |
;156/83,178,179,182,183,221,229,277,280,292,59
;161/122,128,129,141,148 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Quarforth; Carl D.
Assistant Examiner: Gittes; F. M.
Claims
We claim:
1. The process of making a bulky web product which comprises
printing wet strengthened creped and substantially unstretched and
unironed wadding having a crepe ratio of at least 1.5:1 up to about
3.0:1 with an adhesive pattern which is disposed in spaced zones on
the wadding and encompasses at least some valleys as well as peak
areas of the crepe, laminating a thin web of drawn synthetic fibers
to said adhesively patterned wadding to provide the fibers on the
wadding in parallel aligned relation and substantially completely
over the wadding surface, calendering the drawn synthetic fibers to
the creped, unstretched and unironed wadding to smooth the crepe
and to embed the fibers in the adhesive and secure the fibers to
the wadding only with the adhesive of the mentioned pattern so that
a composite of the wadding and fibers is formed, subsequently
dampening the crepe wadding to the extent that the moisture content
of the wadding is at least 30 percent by weight based on the dry
weight of the fiber of the wadding to cause a release of the crepe
structure and distending of the wadding between adhesive zones, and
drying the composite while maintaining the distended structure to
provide a macrocreped bulky web product.
2. The process according to claim 1 in which, prior to dampening of
the composite, two composites are cross-laid into a unitary
assembly with the fibers in inner contacting layers and extending
perpendicularly to each other, and the composites are then dampened
in the form of the assembly to distend the outer wadding layers of
the assembly.
3. The process according to claim 1 in which the creped wadding is
subjected to a steaming to effect the dampening and distending of
the wadding.
4. The process according to claim 1 in which the creped wadding
during the distending process has a moisture content in excess of
100 percent by weight based on the dry weight of the wadding.
5. The process according to claim 1 in which the crepe ratio of the
wadding and the dampening of the wadding between adhesive zones is
such that the wadding distends so that the wadding length between
adhesive zones is at least twice that of the straight line distance
between adhesive zones.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to a composite product of cellulosic wadding
and drawn synthetic fibers and is more particularly concerned with
an improvement in bulked webs and a process of producing the
same.
The Invention
The bulked web contemplated herein exhibits a utility in
applications requiring a degree of surface rugosity as well as
softness, bulk and strength. Such characteristics provide the web
with utility as toweling, washcloths and for wipe material
generally, although it may have application in other areas such as
drape and curtain material.
A particular object of the present invention is the attainment of a
well relaxed cellulosic creped surface material having in the dry
state a very large macrocrepe structure which is quite independent
of the original crepe from which it is formed but dependent upon
other controllable factors such as adhesive disposition and
including a relationship of the adhesive pattern to the crepe ratio
of the cellulosic wadding. The invention will be more fully
understood by reference to the following detailed description and
accompanying drawings wherein:
FIG. 1 is a flow chart of the primary steps of a preferred
embodiment of the invention;
FIG. 2 is an exaggerated view in cross section of one embodiment of
the composite material prior to the distending process;
FIG. 3 is similar to that of FIG. 2 but following the distention
process; and
FIG. 4 is an assembly of crosslaid composites of the structure such
as that illustrated in FIG. 3.
Referring more particularly to the drawings and initially to FIG.
2, numeral 1 generally designates a composite of creped tissue in
the form of cellulosic wadding and a web of drawn fibers which
extends transversely to the hills and valleys of the wadding. The
wadding is designated by the numeral 2 and the web of drawn fibers
by the numeral 4. The drawn web is tensioned and the fibers may be
in close side-by-side contacting relation in known manner. The
numeral 3 designates a zone of adhesive and, as will be noted from
FIG. 2, such zones are well spaced along the length of the
composite. The creped cellulosic wadding for the purposes of this
invention should have a crepe ratio of at least 1.5:1. By this is
meant that a tissue with a crepe ratio of 1.5:1 may be extended to
one and a half times its length if all crepe were removed. Further,
care is taken that the wadding retains substantially all of its
crepe through lamination with the drawn web; this differs from many
wadding operations which are followed by mechanical crepe removal
by stretching and ironing to achieve a less stretchy and somewhat
more soft product. In contrast to the creped wadding, the web of
synthetic fibers supported on the creped wadding has a stretch of
only about 10 percent or less and may be considered as
nonshrinking. In accordance with this invention in the practice of
the process, the fact that the synthetic fibers have very little or
zero shrinkage is an important consideration in the development of
the bulk characteristic by relative distention between the
synthetic fibers and the wadding webs.
As indicated in FIG. 1, the creped wadding designated at 2 (FIG. 2)
printed with an adhesive pattern as indicated at 3 (FIGS. 2 to 4
inclusive) and laminated to the drawn fiber web by means of the
adhesive pattern may be hot calendered to the smooth surface of the
composite and to intimately secure the fibers in the adhesive. In
the practice of the invention the hot calendering may be practiced
on the structure illustrated in FIG. 2. In such event the adhesive
may envelop both hills and valleys of the crepe to a limited
extent. Specifically, the zone occupied by the adhesive is
preferably quite limited although it may be sufficient that in the
calendering operation adhesive binds several hills, for example, of
adjacent crepes together. This is not a necessary characteristic of
the procedure or product but results from the fact that in the
application of adhesive some may, and usually will, occupy
positions on the side hills rather than being confined simply to
the peaks of the crepe. Rugosity is apparently somewhat enhanced by
such disposition of the adhesive.
Following the calendering operation (FIG. 1) to smooth the
composite structure and provide for securing of the fibers by
embedment in the adhesive, commonly it is preferable to cross-lay
two such composites. Most suitably, cross-laying is effected by
positioning the fibers of two composites at right angles to each
other and in contact with each other so that the outer surfaces are
creped wadding. More suitably, the composites are simply pressed
together to cause the adhesive already present to penetrate between
layers and to secure the two composites together. Alternatively if
desired, additional adhesive might be provided to retain the
composites together. In any event, it is preferable, in accordance
with the practice of this invention, to first form an assembly of
at least two composites.
The assembly formed as described is subjected to a dampening
operation. This is for the purpose of increasing the moisture
content particularly of the creped wadding. The dampening operation
will be simply the sprinkling of water on to the wadding of the
assembly. Alternatively, the treatment may be with saturated steam
or with immersion in an aqueous bath. In any event, the moisture
content of the creped wadding should be raised to at least 30
percent based on the dry fiber weight of the wadding. Preferably,
the moisture content is raised to 50 -200 percent based on the dry
weight of the fiber of the creped cellulosic wadding. Importantly,
in these treatments the drawn fibers of the inner webs do not
undergo any material length change. However, the creped cellulosic
wadding distends, losing, in some instances, very nearly all of its
fine initial crepe. When the moisture is supplied to the creped
cellulosic wadding of the assembly in liquid form rather than vapor
form, the time for distending of the wadding between adjacent
adhesive zones is materially shortened. When the moisture content
is obtained by saturated steam or high humidity in the air, the
time for effecting the distending is materially increased and, in
some instances, the relaxation of the crepe between the adhesive
zones will be quite incomplete. Thus, by selection of the mode of
distending the creped wadding, the extent of the release of the
crepe and, consequently, the bulk of the product may be controlled.
We prefer to provide the moisture content of the cellulosic wadding
with steam to about 100 percent to 200 percent so that both
moisture content and temperature tend to aid the distending of the
wadding.
Following the wadding expansion, commonly to the extent that the
length of wadding between adhesive zones is about twice that of the
straight line distance between adhesive zones, the wadding is
dried. Drying is effected simply by passing through any
conventional heating means and may be over rollers if desired. This
is for the reason that there is little adhesive between the creped
wadding itself and the fibers of the drawn webs. Upon drying, the
product attains, in the case of the assembly, a structure such as
that illustrated in FIG. 4. There the section view of the assembly
designated generally by the numeral 1 shows the creped wadding
designated as 2' in the expanded state as secured at well spaced
zones 3 to the crosslaid drawn fibers 4.
In some instances it may be desirable to simply expand the crepe in
the form of composite as designated in FIGS. 2 and 3 rather than in
the form of the assembly. In this instance the product will have on
one side a drawn web of fibers secured to a materially expanded
wadding 2' by the adhesive indicated at 3 in FIG. 3. Two such
expanded composites may be combined to provide the assembly of FIG.
4 if desired. It will be noted that there is, in fact, a distending
or lengthening of the creped wadding between adhesive zones in the
practice of the invention and that such is controlled to provide
the materially bulky sheet noted. There is, in effect, a large
macrocrepe structure which is dependent on the crepe ratio
remaining in the sheet in contrast to the original crepe ratio, the
distance between adhesive zones and, to some extent, the nature of
the adhesive printing pattern, but it is largely independent of the
original crepe. By this latter is meant that the original crepe
structure may vary widely in the number of crepes per inch without
materially affecting, it has been found, the nature and bulk of the
final distended product.
The large macrocrepe remaining in the material is desirable when
employed with the cellulosic creped wadding as it provides for a
combination of softness and rugosity having particular utility in
the area of absorbent wipe materials in the nature of toweling,
facecloths and the like.
We prefer to employ in the practice of the invention creped wadding
having a crepe ratio of between about 1.5:1 and 3:1 and
substantially unstretched and unironed; a smaller crepe ratio tends
to provide too little bulk and a larger crepe ratio tends to
provide an excessive loosening of material between usually spaced
adhesive zones; tissue webs of about 4 to 12 pounds per 2,880 sq.
ft. basis weight before creping serve the purpose well. We also
prefer to provide creped wadding of a relatively fine crepe
structure as such tends to have a better and more regular adhesion
to the strength member and gives a more abrasion resistant surface.
The nature of the wadding which is employed also is a factor in the
speed at which the process would be practiced since higher weights
of wadding tend to hold more fluid and, therefore, require longer
drying times. I therefore prefer to employ for toweling material,
facecloths and the like wadding having a basis weight of between
about 7 and 14 pounds per 2,880 sq. ft.
A suitable adhesive for the practice of the invention is a
plastisol. One useful plastisol is 100 parts of polyvinyl chloride
dispersed in 60 parts by weight of diisodecyl phthalate. This
material is readily formed to a viscosity of 3,000 centipoises
Brookfield as measured with a No. 4 spindle at 20 r.p.m. and may be
applied by conventional roll applicator means. Other adhesives,
however, preferably those which are water-insoluble, may be
employed and they include polyvinyl resins, plasticized or
unplasticized, such as polyvinyl acetate, and the acrylic resins
such as the alkyl acrylates.
Additionally, it is preferable that the creped wadding have a wet
strength treatment and it is preferred to employ conventional wet
strength resin materials such as melamine formaldehyde, urea
formaldehyde, or condensation products of polyamide epichlorohydrin
and the like. Tappi Monograph 13 entitled "Wet strength in Paper
and Paperboard" describes such resins.
It has been noted that the striated web or drawn tensioned web
should exhibit little extension or shrinkage in the practice of the
procedure. Generally, we prefer to employ synthetic fibers of a
length of about one-half to 3 inches or longer and a denier in the
range of 0.5 to 3 as such fibers will lie in closely parallel and
aligned relation and provide a material strength to the product
when formed of fibers of rayon to provide webs having a square yard
weight between about 3 and 20 grams. The webs may be drawn at
speeds of 520 f.p.m. without altering the physical structure of the
web and while maintaining the fibers in a highly aligned condition
(at least 80 percent aligned). Useful staple length fibers include
the rayon mentioned, polyesters, acrylonitriles, polyamides,
polypropylene and other synthetics. Importantly, the fibers chosen
should remain dimensionally stable under conditions of temperature
up to about 300.degree. F. and in the presence of considerable
moisture. A conventional pattern of adhesive places the adhesive
zones spaced at a distance of about three thirty-seconds inch.
Also, 50 crepes per inch would be considered a relatively fine
crepe within the concept of the invention while 10 crepes per inch
would be considered relatively coarse. The calender pressure
exerted should be relatively high to insure of web smoothness and
compaction of the fibers into the adhesive. The adhesive in the
selected pattern should cover at least about 10 percent but not
more than about 30 percent of the area of the composite in order to
provide for adequate bulking of the web.
In specific application a crepe cellulosic wadding sheet of a
thickness of 0.025 inch and wet strengthened by
polyamide-polyamine-epichlorohydrin having a crepe ratio of 2.1:1
and about 40 crepes per inch is printed with an adhesive pattern of
conventional nature; such is commonly termed a brick pattern and is
constituted by adhesive in spaced apart rectangular zones separated
by nonadhesive areas. The adhesive is applied over 16.7 percent of
the wadding area and to some extent coats both the hills and
valleys of the fine crepe structure; the adhesive is applied by
roll applicator means and is composed of a plastisol of about 100
parts of polyvinyl chloride and 60 parts by weight of diisodecyl
phthalate. This adhesively treated crepe wadding is laminated to a
drawn fiber web of rayon of a square yard weight of about 5.0
grams. The fibers have a denier of 1.5 and are parallel aligned to
the extent of about 85 percent and in close contacting relation.
The lamination step is followed by a hot calendering action which
smooths the composite and simultaneously secures the fibers to the
wadding. Cross-laying of such composite is conventional as already
described. The resulting assembly was thoroughly wetted with water
and then dried at a temperature of 80.degree. C. Upon drying, the
creped wadding had bulked up and the overall thickness of the two
ply composite was 0.051 inch. Prior to the bulking process the
composite had a bulk of 0.019 inch. Thus, the bulk increase was
about 2.7 times.
The strength and elongation characteristics of the web are
determined largely by the tensioned aligned fibers which cover the
creped wadding; the wadding determines the important absorbency,
wet feel and other characteristics important on facecloth and
similar applications.
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.
* * * * *